Дисертації з теми "Possums"
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1
Osugi, Mizuho. "Measuring Auditory Thresholds in Brushtail Possums (Trichosurus Vulpecula)." The University of Waikato, 2008. http://hdl.handle.net/10289/2422.
Анотація:
A total of 9 brushtail possums (Trichosurus vulpecula) were trained to perform a two-manipulanda, conditional discrimination task. The possums learned to press a right lever in the presence of a tone (80 dB(A)) during tone-on trials, and a left lever in the absence of the tone on tone-off trials. Overall sessions of 11 conditions contained tone frequency between 100 Hz and 35 kHz were tested. Each condition contained training and then probe sessions. In training sessions, the possums were presented with tone-on and tone-off trials, pseudo-randomly. Once the possums responded with over 90% accuracy for five consecutive sessions, then probe sessions were introduced. Probe sessions were similar to the training sessions, except that the tone intensity for tone-on trials was reduced by 8 dB(A) across blocks of 20 trials until their response accuracy in a block fall below 60% or reached 24 dB(A). Data were analysed using overall percentages correct and log d analysis. Both measures indicated that overall response accuracy decreased for all possum as tone intensity reduced. Based on these data analyses, threshold values were calculated using the criterions at 75% correct and a log d of 0.48. The threshold values for each possum and across all possums were plotted as a function of the tone frequency to produce an audiogram. A curvilinear regression was fitted for each threshold values. The functions of both measures were very similar. Both audiograms showed that the possums could hear the tones between 100 Hz and 35 kHz, and were most sensitive to tones between 15 and 20 kHz. This experiment involved many difficulties with producing and measuring tones especially outside of human hearing range. Due to these difficulties, several problems and concerns were raised during the experiment, these were discussed in this study and also recommendations for future research were then presented.
2
Eymann, Jutta. "Management of urban common brushtail possums (Trichosurus vulpecula)." Doctoral thesis, Australia : Macquarie University, 2007. http://hdl.handle.net/1959.14/6.
Анотація:
Thesis by publication -- 8 co-authored articles.Thesis (PhD)--Macquarie University, Division of Environmental and Life Sciences, Department of Biological Sciences.
Includes bibliographical references.
Preface -- Management issues of urban common brushtail possums (Trichosurus vulpecula): a loved or hated neighbour -- Effects of deslorelin implants on reproduction in the common brushtail possum (Trichosurus vulpecula) -- Brushtail possums (Trichosurus vulpecula) in metropolotan Sydney: population biology and response to contraceptive implants -- Strategic survey for Toxoplasma gondii and Neospora caninum in the common brushtail possum (Trichosurus vulpecula) from urban Sydney, Australia -- Leptospirosis serology in the common brushtail possum (Trichosurus vulpecula) from urban Sydney, Australia -- Conclusions.
The common brushtail possum (Trichosurus vulpecula) is indeed a common inhabitant of many Australian citites, and one of the few marsupials that has adapted well to the urban environment. Their close proximity to people provides a great opportunity to experience native wildlife in the backyard, however, their utilization of house roofs, bold behaviour and appetite for garden plants often leads to conflict with householders. Population numbers are sufficiently high to require ongoing management to minimise negative impacts for humans and brushtail possums alike in a socially acceptable manner. The aim of this thesis was to identify current management issues and address the need for improved and novel management strategies. The potential of slow-release implants, containing the GnRH agonist deslorelin, as a contraceptive agent for brushtail possums was tested on a captive population. Males appeared resistant to treatment, but deslorelin was found to inhibit reproduction in female brushtail possums for at least one breeding season, making it a promising tool to control fertility in some wild populations. A further aim was to trial deslorelin implants on a wild urban population, to collect more information about the urban biology of this species and to point out issues which have previously not been addressed. Close proximity and interaction of urban brushtail possums with humans and their domestic animals can increase the risk of disease exposure and transmission and influence the health of wild populations. Serosurveys showed that animals were readily exposed to Leptospira spp. and Toxoplasma gondii. This thesis also provides the first data on brushtail possum dispersal in urban areas, knowledge which is highly relevant to the development of management strategies such as fertility control. The findings from this research broaden our knowledge about urban brushtail possums and should assist wildlife authorities in developing alternative or improved management procedures.
Mode of access: World Wide Web.
xxv, 287 p. ill., maps
3
Rivas, Ryan. "Good Fences and Dead Possums and Other Short Stories." Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/797.
Анотація:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucfBachelors
English
Arts and Sciences
Creative Writing
4
Morgan, D. R. "Maximising the effectiveness of aerial 1080 control of possums (Trichosurus vulpecula)." Diss., Connect to this title online, 2004. http://theses.lincoln.ac.nz/public/adt-NZLIU20060911.123107/index.html.
5
Morgan, David R. "Maximising the effectiveness of aerial 1080 control of possums (Trichosurus vulpecula)." Lincoln University, 2004. http://hdl.handle.net/10182/20.
Анотація:
Aerial control using 1080 (sodium monofluoroacetate) baits is widely used in New Zealand for the control of introduced brushtail possums (Trichosurus vulpecula), with the aim of protecting national conservation and agricultural values from these damaging pests. This thesis integrates research, completed over 25 years, that was motivated by growing recognition in the 1970s of the extent of possum impacts and the need to improve the effectiveness and efficiency of the control operation. Field research assessed the palatability of three types of cereal-based pellet baits and carrot baits in different regions, habitat types and seasons. Palatability was assessed by the consumption of the different bait types presented independently of each other on 15-30 plots, with rotation of bait types at plots on successive nights to provide equal exposure to each bait type. There was regional variation in possums' bait preferences, possibly reflecting genotypic differences, whereas seasonal variation was less evident. Carrot bait was preferred or equally preferred to cereal bait in 14 out of 20 field trials. The proportion of possums eating baits was then investigated by, firstly, developing a technique for tracing bait acceptance using rhodamine B, a UV-fluorescent dye. In four field trials, more than 95% of possums accepted three types of dye-marked bait, eliminating bait refusal as a major reason for low kills in winter control operations. In a fifth trial, conducted in summer, only 68% of possums accepted bait suggesting that seasonal availability of favoured foods may influence bait acceptance. Since possums must encounter baits before deciding whether to eat them, field studies were undertaken to assess the coverage achieved in normal aerial baiting operations. Large gaps, up to 400 m in width, were often found between baiting swaths; these could allow some possums to survive. A controlled field experiment, using acceptance of rhodamine-dyed bait as a measure of effectiveness, showed that bait distribution was least accurate where flight paths were not marked. Where gaps of 100 m between flight paths were deliberately created, bait acceptance was slower and less than where coverage was complete. Sowing baits at 3 kg/ha was as effective as at 10 kg/ha, indicating the potential for substantially reducing operational costs by using machinery capable of faultlessly distributing baits at low rates. Navigational guidance systems were evaluated and found to improve the accuracy of bait distribution. During 1993-1997, when a lower sowing rate of 5 kg/ha was adopted operationally by regional managers, control effectiveness was unchanged but annual savings of around $9 million accrued. Because of the lack of suitable sowing machinery, a bucket was developed to permit faultless distribution of baits at lower rates, demonstrating the possibility of yet further cost-savings. The possibility of seasonal food availability affecting bait acceptance was investigated in three different forest habitats. Dyed baits were aerially distributed on 100 ha at each site in each season over two years. In each trial, fat-based condition indices of possums were calculated and the abundance of possum-preferred plant foods described. Bait acceptance was consistently high (85-100%) in the 24 trials, and was not influenced by either condition or availability of preferred foods. It seems likely that seasonal variation in operational effectiveness is caused by either the availability of sharply seasonal, scarce foods that possums may feed on intensively for brief periods, or by warmer temperatures that render 1080 less effective. The influence of 1080 on acceptance of (rhodamine-dyed) baits was investigated in a field trial. Examination of possums for dye-marking showed that 25% of possums refused to eat either a lethal quantity of bait or any bait at all, compared with 98% of possums eating non-toxic bait. This indicated that 1080 is aversive to possums, which is a potential major reason for their surviving control operations. Pen trials were therefore conducted to further examine the problem and to seek solutions. Toxic carrot baits were rejected by 27.5% of possums, equally by smell and taste aversion, whereas toxic cereal pellets were rejected by 34%, mainly by taste aversion. Orange and cinnamon were shown to be among the most preferred of 42 flavours tested and, when applied to toxic baits, 1080 was effectively masked. Bait refusal was reduced to ≤7%, the same as that recorded for possums presented with flavoured non-toxic baits. For long-term control of possum populations, aerial 1080 baiting can be used sequentially with other poisoning methods. However, the compatibility of these methods is dependent on the likelihood of possums developing bait shyness if sublethally dosed. Studies were therefore conducted to characterise and compare the four main toxicants used (1080, cyanide, cholecalciferol and brodifacoum) for induction and mitigation of bait shyness. Shyness was induced in approximately 80% of possums sublethally dosed with cyanide, 60% with 1080, 20% with cholecalciferol, and 0% with brodifacoum. Cyanide and 1080 shyness were found to persist in many possums for at least 12 and 24 months, respectively. Use of alternative bait types, and of baits containing an alternative slow-acting toxin (brodifacoum) were shown to be effective ways of overcoming shyness. This, and other related research, is reviewed to provide operational specifications that maximise the likelihood that all targeted possums will (i) encounter bait, (ii) eat it, and (iii) die. The likely future use of aerial 1080 baiting is described and the technological, economic, environmental and social constraints on its sustainability are discussed. Finally, the uptake of the research by possum managers is considered, and areas identified in the thesis where information is incomplete are summarised as prioritised topics for further research.
6
Roberts, Karen K. Biological Earth & Environmental Sciences Faculty of Science UNSW. "Oligo-Miocene pseudocheirid diversity and the early evolution of ringtail possums (Marsupialia)." Awarded By:University of New South Wales. Biological, Earth & Environmental Sciences, 2008. http://handle.unsw.edu.au/1959.4/41517.
Анотація:
The marsupial family Pseudocheiridae is currently known from seventeen species of six genera in Australia and New Guinea. These small to medium-sized arboreal animals are nocturnal and folivorous. Extinct pseudocheirids are recognised from several mid to late Cenozoic fossil localities across Australia and New Guinea. The single largest collection of pseudocheirid fossils has been recovered from the Oligo-Miocene freshwater carbonates of the Riversleigh World Heritage Area in northwest Queensland. This collection, which includes the first pseudocheirid cranial fossils, forms the basis of this investigation. Three new extinct pseudocheirid genera together containing four species are identified and described. Six new species of Paljara, Marlu and Pildra are also described from Riversleigh. Two of the new Marlu species are reported from South Australia??s Leaf Locality. From Riversleigh, Marlu kutjamarpensis is identified and additional material of Paljara tirarensae and P. nancyhawardae documented. New species attributed to Marlu and Pildra necessitate revision of those genera. Cranial material is identified for three of the new species. The rostrum of archaic pseudocheirids is shorter than in extant forms but cranial morphology is similar overall. Phylogenetic relationships of all extinct pseudocheirids are analysed. They include all new and previously described species, most of which have never been examined in a parsimony-based analysis. Two hypotheses of pseudocheirid evolution are presented: a paired lineage hypothesis and a single lineage hypothesis. Both hypotheses demonstrate that species of Paljara are not the most plesiomorphic pseudocheirids, Marlu praecursor does not cluster with other species of Marlu, the new genus Gawinga is most closely related to Paljara and there are no representatives of the extant genus Pseudochirops in any pre-Pliocene locality. All extant pseudocheirids cluster to form a crown clade sister to a stem lineage of Pseudokoala and Marlu species. Pseudocheirids are found in all Oligo-Miocene faunal zones of Riversleigh. Species of Paljara and Marlu are most frequently recovered from Faunal Zone B and C deposits respectively. Four pseudocheirid species biostratigraphically correlate the Kutjamarpu local fauna of the Leaf Locality with Faunal Zones B and C of Riversleigh, suggesting an early to middle Miocene age for both deposits. Modern pseudocheirids first evolved no later than the late Miocene from a descendant of the Marlu + Pseudokoala lineage when all other Oligo-Miocene pseudocheirids became extinct. At least three pseudocheirid lineages dispersed to New Guinea approximately five million years ago, but ecological barriers probably prevented subsequent migrations between the two landmasses.
7
Anthony, Clare. "How dependent are honey possums, Tarsipes rostratus, on their key winter food-plants?" Thesis, Anthony, Clare (1996) How dependent are honey possums, Tarsipes rostratus, on their key winter food-plants? Honours thesis, Murdoch University, 1996. https://researchrepository.murdoch.edu.au/id/eprint/40780/.
Анотація:
The study aimed to examine the dependence of the honey possum, Tarsipes rostratus on the winter-flowering plants Banksia baueri, Dryandra plumosa and D. cuneata. Sampling of honey possum populations was carried out in six paired Grids in the Fitzgerald River National Park. The capture rate and various other population parameters was measured before and after the removal of flowers of these species in the Treatment Grids and then compared with populations in the Control Grids.
Throughout the study, the flowering pattern of plants visited by honey possums was examined. Different plant species in the Proteaceae and Myrtaceae families had highly seasonal flowering patterns and there were several species in flower in each sampling month, suggesting that a continuous nectar supply was available to Tarsipes throughout the year. A peak in flowering occurred during the winter and spring months. Banksia baueri flowered most prolifically in July and the flowering intensity of D. cuneata ' increased through the winter to reach a peak in the early spring in most areas. The flowering of D. plumosa showed much less seasonal variation and flowered continuously for the duration of the study.
During the winter, the population density of Tarsipes was limited by the supply of nectar and pollen and, during the manipulation, numbers were lower than expected and did not rise to their usual winter peak. The removal of B. baueri flowers had the greatest effect whereas removal of D. plumosa had the least effect. These changes in population size occurred as a result of the movement of individuals, particularly males, out of the cut Grids to areas with a greater abundance of nectar and pollen. Movement between Grids was negligible suggesting that honey possums that moved out of the Treatment Grids only moved short distances to the nearest flowering plants.
Flower removal did not appear to influence dramatically the structure of honey possum populations. During the manipulation, the proportion of females in the Treatment populations increased as a result of the movement of males out of the area. However, the populations that remained in these Grids did not differ greatly in structure from those in the Control Grids. There was no change in the number of females with pouch young and, hence, the age structure of the populations remained the same. There was also no difference in the proportion of recaptures in each Grid. Flower removal also appeared not to have a deleterious effect upon the body condition of individuals.
Tarsipes visited flowers from a wide range of species in the Proteaceae and Myrtaceae families and their diet was highly seasonal. When the food supply was reduced in the winter, honey possums did not feed on flowers from any new species of plant. Rather, they appeared to feed more intensively on species that were already a component of their diet. This applied particularly to Calothamnus gracilis and, to a lesser extent, D. nivea, B. gardneri var. hiemlis and B. coccinea.
Finally, no significant relationship was found between the distribution of captures within each Grid and the distribution of B. baueri, D. plumosa and D. cuneata plants, suggesting that honey possums forage at random for nectar within their habitat.
8
Herron, Fiona Michelle. "A study of digesta passage in rabbits and ringtail possums using markers and models." University of Sydney. Biology, 2002. http://hdl.handle.net/2123/483.
Анотація:
The common ringtail possum (Pseudocheirus peregrinus), a member of the family Pseudocheiridae, is an arboreal folivorous marsupial that feeds predominantly on Eucalyptus foliage. Contrary to the expectation that small body size would inhibit utilisation of a diet containing such high levels of lignified fibre because of relatively low gut volume to body mass ratios and relatively high mass-specific metabolic rates and nutrient requirements (Hume 1999), the ringtail possum is able to survive solely on a diet of Eucalyptus foliage. The rabbit (Oryctolagus cuniculus) is a terrestrial herbivore and is a member of the family Leporidae that feeds predominantly on grasses. The rabbit was proposed as a digesta flow model for the ringtail possum since both are caecotrophic (periodically re-ingest caecal contents) and both are proposed to exhibit a colonic separation mechanism (CSM) where fluids and small, easily digested particles are preferentially returned to the caecum. The rabbit is of value for the modelling process since it is more accessible for experimental manipulation than the ringtail possum. This study investigated a proposal to use digesta passage through the gastrointestinal tract (GIT) of the rabbit as a model of digesta passage for the ringtail possum on the basis that both are caecotrophic caecum fermenters. A number of potential problems were identified with this proposal and investigation of these problems formed the basis for the research described in this thesis. Two main areas were identified as being potentially problematic: 1) fundamental flaws with the particulate markers used in digesta rate of passage studies; and 2) differences in animal behaviour and natural diet between the two subject species which suggested different digestive strategies and hence different patterns of digesta flow through the GIT. The proposed digesta passage markers were lanthanide metals (Dy, Tm, Eu and Yb) attached to either fibrous particles (1200 - 600�m) or formalin-fixed rumen bacteria (20 � 0.2�m). These markers were shown to not be of the assumed size classes and the extent of lanthanide metal binding differed between the four metals used. An effect due to method of dosing was also observed. The findings of marker inconsistencies caused major limitation to model development and further research is necessary to clarify these markers. The proposal to use digesta flow in the rabbit GIT as a model for digesta flow in the ringtail possum was shown to be idealistic due to the differences in anatomy and behaviour observed between the two herbivores. Laboratory observations, time series analysis and compartmental modelling confirmed the differences between the animals. This study showed: 1) the GIT of the rabbit was more complex both anatomically and functionally than that of the ringtail possum; 2) behaviour affecting digesta passage of the rabbit and ringtail were different and; 3) compartmental models confirmed the anatomical and behavioural findings. Digesta passage in the rabbit could not be modelled mathematically using data on digesta passage due to complexities of the system. In contrast, a basic model was constructed for digesta passage in the ringtail possum. On the basis of these findings, the research hypothesis "that digesta passage in rabbits is similar to that in ringtail possums" was rejected.
9
Ricci, Mario. "The marsupial sperm tail cytoskeleton : a morphological and biochemical study /." Title page, table of contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phr4911.pdf.
10
Dundas, Shannon. "Utilisation of Phytophthora cinnamomi affected habitats by honey possums (Tarsipes rostratus) in the Cape Riche area, Western Australia." Thesis, Dundas, Shannon (2008) Utilisation of Phytophthora cinnamomi affected habitats by honey possums (Tarsipes rostratus) in the Cape Riche area, Western Australia. Honours thesis, Murdoch University, 2008. https://researchrepository.murdoch.edu.au/id/eprint/15328/.
Анотація:
This study investigated how the presence of the plant pathogen Phytophthora cinnamomi in vegetation assemblages impacts on habitat utilisation by the honey possum (Tarsipes rostratus). The study took place in coastal heathlands at Cape Riche, Western Australia, between January 2007 and November 2007. Honey possums were radio tracked through an area affected with P. cinnamomi as well as healthy areas to determine the extent to which habitat utilisation is impacted on. This will then allow for a more robust prediction of how further spread of P. cinnamomi is likely to impact on honey possums in the future. The presence of P. cinnamomi was confirmed by plating samples of dying plants. The areas of P. cinnamomi at the study site are extensive but patchy with ‘islands’ of healthy vegetation assemblages still remaining. A comparison of microclimate at the study site showed that unaffected areas had a larger range of temperatures than affected areas which may be due to differences in wind which is restricted (having a buffering effect) due to dense vegetation in unaffected sites. In affected areas, a greater proportion of the time was recorded where temperature was below 5C compared with unaffected areas. This could potentially impact on honey possums, which go into torpor during cool weather, and at temperatures below 5C, have a higher metabolic rate to maintain their body temperature. This means they need to forage for more nectar and pollen during cooler weather in affected areas where foodplants are less abundant. The number of honey possums captured was correlated to season (2=13.1, p<0.0005) with the largest number of honey possums captured during the summer field trip when more plants were flowering.
Honey possum preferred foodplants were identified from pollen collected from captured honey possums. A total of 20 different pollen species were identified from samples, nine of which were identified as important honey possum preferred foodplants as they were found in more significant amounts. Based on pollen, Banksia plumosa subsp. plumosa was identified as the preferred foodplant at the Cape Riche study site followed by Adenanthos cuneatus. Both are common throughout the study area and flower all year.
Banksia plumosa subsp. plumosa is susceptible to P. cinnamomi and was only found in unaffected areas whereas Adenanthos cuneatus was found to less susceptible and was prevalent throughout P. cinnamomi affected areas. Honey possums fed on a diverse range of plant species (determined by pollen) during all seasons, except autumn when B. plumosa subsp. plumosa was the most prevalent pollen species collected from honey possums.
A total of 18 honey possums (body mass 5.9 – 16g) were radio tracked for up to 9 days using radio transmitters weighing 0.36g and 0.9g (Holohil Systems Ltd, Canada). Radio tracked honey possums demonstrated a particular preference for Banksia plumosa subsp. plumosa which they utilised for food, shelter and as a daytime refuge. Comparison of vegetation structure indicated that sites selected by radio tracked honey possums had significantly denser vegetation between 40-140 cm in height compared with randomly selected sites. Significant differences were identified between Phytophthora cinnamomi affected and unaffected locations with vegetation at affected locations being sparser and shorter than that at unaffected sites.
This study clearly showed that honey possums are influenced by the presence of P. cinnamomi affected vegetation at Cape Riche. The presence of P. cinnamomi at the study area results in large areas which are generally lacking in susceptible Proteaceous species such as Banksia and food resources tend to be sparse through these areas. Honey possums are capable of moving relatively large distances with estimated distances ranging from 4m to 1400m over a period of 30 minutes to 9 days. In areas affected with P. cinnamomi some honey possums fed on less susceptible plant species. Other honey possums moved long distances to healthy unaffected areas with higher densities of preferred foodplants. Further spread of P. cinnamomi is likely to have a serious impact on honey possums as healthy areas become affected and food resources become too limited to sustain honey possum populations.
11
Hardaker, Bethany Jane. "A study of short-term remembering in the possum : using a delayed-matching-to-sample procedure /." The University of Waikato, 2006. http://hdl.handle.net/10289/2354.
Анотація:
In Experiment one 7 Brushtail possums were trained, using food, to perform a Delayed-Matching-To-Sample procedure using still and flickering light stimuli, over a 0, 1 and 2 second delay. A criterion of 80 percent correct for 5 consecutive days was set for the requirement to probe test. Probe session delays were 0, 0.5, 1, 2, 4, and 8 seconds. Performance was analysed using the measure of discrimination log d. Log d = 1 at the possums training delay and dropped back to log d = 0 at the longer inexperienced delays. The possums performance at this task was only adequate, so in case the stimuli were causing discrimination difficulties they were changed for the following experiment to horizontal and vertical light stimuli. Experiment two used the horizontal and vertical light stimuli to further test DMTS in possums. The possum's responding stayed at 50 percent correct, or chance, so the task was changed to a Simultaneous-Choice procedure. However, this did not have any effect on improving their results with responding accuracy remaining at 50 percent correct. Experiment three involved a conditional discrimination procedure, which was implemented to find out whether the possums could in fact discriminate between a horizontal and vertical light. All the possums in this experiment reached 80 percent correct overall and at responding to either a horizontal or vertical light. These results are enough to conclude that it was not the stimuli used in the previous two experiments which that had been causing the difficulties but the task itself. It is not known exactly why the possums were so unsuccessful in performing a DMTS or MTS task. More research into DMTS in possums in greatly needed and would offer a better understanding of the results of this study.
12
Caley, Peter, and n/a. "Inference on the host status of feral ferrets (Mustela furo) in New Zealand for Mycobacterium bovis infection." University of Canberra. Resource, Environment & Heritage Studies, 2001. http://erl.canberra.edu.au./public/adt-AUC20050621.140940.
Анотація:
This thesis is about making inference on the host status of feral ferrets in New
Zealand for Mycobacterium bovis, the aetiological agent of bovine tuberculosis. The
central question addressed is whether the rate of intra-specific transmission of M. bovis
among ferrets is sufficient for the disease to persist in ferret populations in the absence
of external, non-ferret sources of infection (inter-specific transmission). The question is
tackled in three parts�firstly using model selection to identify suitable models for
estimating the force of M. bovis infection in ferret populations; secondly applying
statistical hypothesis testing to the results of planned manipulative field experiments to
test the relationship between M. bovis infection in brushtail possums and that in ferrets;
and thirdly using modelling to estimate intra-specific disease transmission rates and the
basic reproductive rate (Ro) of M. bovis infection in ferrets.
The model selection approach clearly identified the hypothesis of oral infection
related to diet was, as modelled by a constant force of infection from the age of
weaning, the best approximation of how M. bovis infection was transmitted to ferrets.
No other form of transmission (e.g., during fighting, mating, or routine social
interaction) was supported in comparison. The force of infection (λ) ranged from 0.14
yr-1 to 5.77 yr-1, and was significantly higher (2.2 times) in male than female ferrets.
Statistical hypothesis testing revealed transmission of M. bovis to ferrets
occurred from both brushtail possums and ferrets. The force of M. bovis infection in
ferrets was reduced by 88% (λ=0.3 yr-1 vs. λ=2.5 yr-1) at sites with reductions in the
population density of sympatric brushtail possum populations. A smaller decline in the
force of infection resulting from the lethal cross-sectional sampling of the ferret
populations was also demonstrated.
The modelling approach estimated the basic reproductive rate (Ro) of M. bovis
infection in ferrets in New Zealand to vary from 0.17 at the lowest population density
(0.5 km-2) recorded to 1.6 at the highest population density (3.4 km-2) recorded. The
estimates of Ro were moderately imprecise, with a coefficient of variation of 76%.
Despite this imprecision, the Ro for M. bovis infection in ferrets was significantly less
than unity for all North Island sites surveyed. Hence it is inferred ferrets are spillover
hosts (0
13
Ruschke, Alexander. "POSSuMUS." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-177710.
Анотація:
The development of a modular designed large scale scintillation detector with a two-dimensional position
sensitivity is presented in this thesis. This novel POsition Sensitive Scintillating MUon SiPM
Detector is named POSSuMUS.
The POSSuMUS detector is capable to determine the particle’s position in two space dimensions with
a fast trigger capability. Each module is constructed from two trapezoidal shaped plastic scintillators
to form one rectangular shaped detector module. Both trapezoids are optically insulated against each
other. In both trapezoids the scintillation light is collected by plastic fibers and guided towards silicon
photomultipliers (SiPMs). SiPMs are light sensors which are capable to detect even smallest amounts
of light. By combining several detector modules, position sensitive areas from 100 cm2 to few m2
are achievable with few readout channels. Therefore, POSSuMUS provides a cost effective detector
concept.
The position sensitivity along the trapezoidal geometry of one detector module is achieved by the
path length dependent amount of detected light for crossing particles. The ratio of the light yields
in both trapezoids is calculated. This value corresponds to the position of the particle traversing the
detector. A spatial resolution in the order of several mm is foreseen. The position sensitivity along the
scintillator module is determined by the propagation time of light to the SiPMs located on opposite
sides of the detector. A spatial resolution of few cm is expected for this direction.
The POSSuMUS detector is applicable as large area trigger detector with a two dimensional position
information of crossing particles. This is suitable in detector tests of large area precesion detectors or
for measuring the small angle scattering of cosmic muons.
At the beginning of this thesis, the determination of important SiPM characteristics like the breakdown
voltage is presented. In the course of this work the detector principle is proven by the test of the
first prototype detector with straight tracks during an experiment at CERN. In particular, a position
sensitivity in both directions is demonstrated. After this experiment the detector development focuses
on the enhancement of the amount of detected light per event. Here several studies with results are
presented.
The gained knowledge is realized in a second prototype detector, whereby the results of straight and
inclined tracks are presented. A position sensitivity due to the trapezoidal geometry is obtained, with
a spatial resolution of up to 13 mm.
This thesis concludes with an outlook on the ongoing developments and to the future use of the POSSuMUS detector.
14
Mella, Valentina S. A. "Physiological and behavioural responses of Australian and exotic prey to the scent of native and introduced predators." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/350.
Анотація:
This study examined the physiological and behavioural effects of a stress-inducing stimulus (predator odour) on potential prey species (Australian native and exotic). The aim was to determine if differences in the response of prey were related to the scent of evolutionary known predators compared to unfamiliar or short-term introduced ones. In laboratory experiments, responses were always restricted to changes in respiratory variables, with brushtail possums (Trichosurus vulpecula), rabbits (Oryctolagus cuniculus) and tammar wallabies (Macropus eugenii) showing no variation in metabolic rate after exposure to predator odours.Brushtail possums showed strong changes in ventilatory rate only when faced with the scent of an historical predator, increasing respiratory frequency (ratio after/before exposure = 4.55 ± 1.007) and decreasing tidal volume (ratio after/before exposure = 0.38 ± 0.113 ) in response to stale dingo urine. The changes were short-lived, lasting for only one minute of exposure. For this reason, it is unclear if the response observed could be considered as a fear reaction. However, there was no habituation after three exposures and this may indicate that possums were initially displaying an investigative approach to a predator scent and then relaxing once assessment was completed.The effect of predator and novel odours on the ventilation of rabbits appeared to be in general mediated by anxiety, as shown by the responses elicited by both predator and control scents. However, stronger reactions were observed in response to feral cat and quoll odours for both respiratory frequency (ratio after/before exposure to feral cat = 4.39 ± 0.721 and to quoll = 3.75 ± 0.486) and tidal volume (ratio after/before exposure to feral cat = 0.47 ± 0.065 and to quoll = 0.64 ± 0.129). This could be due to different intensity of the olfactory stimuli. Nevertheless, the effects of noxious odours on rabbits clearly demonstrate that they become highly vigilant at any sudden change in their environment.Tammar wallabies appeared to possess a mechanism for the recognition of predator odours as ventilatory responses were restricted to particular predator scents. After investigation, fox and cat odour provoked a stronger and more prolonged change in respiratory frequency (ratio after/before exposure to fox = 3.58 ± 0.918 and to feral cat = 2.44 ± 0.272) and tidal volume (ratio after/before exposure to fox = 0.84 ± 0.110 and to feral cat = 0.98 ± 0.155) compared to the other scents, suggesting that wallabies may have perceived these species as more immediate threats.For wild, free-living brushtail possums and southern brown bandicoots (Isodoon obesulus), there was no pattern of avoidance of historical or introduced predator odours, with no difference in number of animals captured in predator and control scented traps. This may indicate that predator odour avoidance has not evolved in these species and that they have poor possibilities of escaping potential predators. However it may also be explained by the long-term predator-free environment in which the study was conducted, and suggests loss of anti-predator behaviour in populations without predation risk.Wild, free-ranging western grey kangaroos (Macropus fuliginosus) reacted to the odour of both historical (dingo) and novel (fox) predators by reducing number of feeding events (5.2±2.08 for fox and 5.9±1.33 for dingo) and time spent foraging (17.7±7.2 sec for fox and 22.2±4.6 sec for dingo) when predator scents were present and by escaping areas tainted with predator odours (41.4±17.5 sec for fox and 33.8±13 sec for dingo). Clearly these results suggest that kangaroos are scared of predator odours. However, a close investigation of predator scents was necessary before a response could be elicited and feeding areas were not completely abandoned.It is still unclear if small Australian prey, such as southern brown bandicoots and brushtail possums, respond to olfactory cue of predation in the wild, as different results were obtained in the studies conducted in the laboratory and in free populations. However, this research showed that medium and large-sized macropods respond to both native, long-term and introduced predator odours. This indicates that at least some Australian prey species can recognise the odour of potential predators, although responses usually occur after a period of investigation, and do not always result in avoidance behaviour. Differential responses appear to be based on the perceived risk. Use of predator odour is unlikely to be an effective mechanism of deterring herbivores from preferred feeding locations.
15
Everaardt, Annika. "The impact of fire on the honey possum Tarsipes rostratus in the Fitzgerald River National Park, Western Australia." Thesis, Everaardt, Annika (2003) The impact of fire on the honey possum Tarsipes rostratus in the Fitzgerald River National Park, Western Australia. PhD thesis, Murdoch University, 2003. https://researchrepository.murdoch.edu.au/id/eprint/66/.
Анотація:
The honey possum Tarsipes rostratus is a tiny (7 - 12 g) highly specialised flower-feeding marsupial endemic to the south-western corner of Australia. The impact of fire on this small mammal was studied, over a 19-year period, in the Fitzgerald River National Park, a large (330,000 ha) area of relatively undisturbed heathland/shrubland, rich in the proteaceous and myrtaceous plants upon which the honey possum appears to rely for food. The honey possum is the most abundant and widespread mammal in this Park.
Capture rates of honey possums were significantly related to the years since the vegetation was last burnt, annual rainfall in the preceding (but not the current) year, the season when trapping occurred, and the trapping grid operated. Capture rates declined markedly after fire and remained low (less than one third of those in long unburnt vegetation) for about 4 - 5 years following a fire. Rates of capture then increased steadily over the next 20 - 25 years, with maximal abundance recorded about 30 years after fire. Thereafter, there appeared to be a slight decline in capture rates, but even in the vegetation unburnt for longest (> 50 years since fire), honey possum abundance was substantial and relatively stable. In contrast to these changes in abundance, the structure of the honey possum population, with 79 % adults and 57 % males, appeared little influenced by fire history, annual rainfall, season or grid.
The increase in the rates of capture of honey possums following fire paralleled the pattern of availability of cover in the vertical and, to a lesser extent, horizontal plane. Indeed, projective foliage cover took around 20 years after fire to reach levels similar to those available in areas unburnt for even longer. The trend in capture rates was also congruent with the maturation of the most frequently visited foodplants of honey possums, particularly Banksia nutans (summer flowering) and B. baueri (winter flowering). Areas long unburnt still contained shelter and foodplants adequate for honey possums even 50 years or more after fire, with only slight evidence of senescence.
Pollen loads indicated that honey possums caught in burnt areas, where their preferred foodplants were absent, continued to feed on these favoured foodplants (Banksia and Dryandra spp.) at nearby unburnt areas. In addition, they also fed, in both burnt and long unburnt areas, upon a suite of other plant species that regenerated more rapidly from lignotubers and epicormic buds, as well as from seeds (e.g. Eucalyptus and Calothamnus spp.). Thus, honey possums appeared to persist with their preferences for feeding from a limited number of flowering plants despite some of these species not being available in recently burnt areas for many years. Nearby patches of unburnt vegetation can clearly be important refuges, feeding grounds and shelter for the few honey possums that visit recently burnt areas, and appear to be the source of honey possum colonists in the years following a fire.
Capture rates were also greater following years when rainfall was higher than average. Indeed, rainfall had as great an influence upon capture rates as time since fire. Capture rates were also consistently higher over winter, and to a lesser extent over summer, than in either autumn or spring. Individual grids, even those close together in apparently similar vegetation with a similar fire history, still differed significantly overall in their capture rates of honey possums. This last finding has implications for the use of chronosequences in the study of post-fire changes in biota.
Although not the primary focus of the study, data on the limited suite of other, far less abundant, small mammals present indicated that house mouse Mus musculus domesticus numbers peak soon after fire (about two years after fire), grey-bellied dunnart Sminthopsis griseoventer numbers somewhat later (about eight years after fire) and that southern bush rats Rattus fuscipes fiuscipes, like honey possums, are later successional species. Most species were present in vegetation over a range of post-fire ages, with data consistent with models based on sequential changes in relative abundance.
Like many Australian mammals, the range of the honey possum has contracted substantially over the last 200 years and the coastal heathlands of the south-west are its last stronghold. In terms of its conservation, this study indicates that, if possible, management burns in these heathlands should be separated by intervals of at least 20 years between successive burns, and preferably even longer. If burns are required more frequently to meet other management priorities, it is highly preferable that they are small and patchy, rather than large scale. Such practices may help ensure the long-term survival of this unique, highly specialised and endemic marsupial.
16
Everaardt, Annika. "The impact of fire on the honey possum Tarsipes rostratus in the Fitzgerald River National Park, Western Australia." Everaardt, Annika (2003) The impact of fire on the honey possum Tarsipes rostratus in the Fitzgerald River National Park, Western Australia. PhD thesis, Murdoch University, 2003. http://researchrepository.murdoch.edu.au/66/.
Анотація:
The honey possum Tarsipes rostratus is a tiny (7 - 12 g) highly specialised flower-feeding marsupial endemic to the south-western corner of Australia. The impact of fire on this small mammal was studied, over a 19-year period, in the Fitzgerald River National Park, a large (330,000 ha) area of relatively undisturbed heathland/shrubland, rich in the proteaceous and myrtaceous plants upon which the honey possum appears to rely for food. The honey possum is the most abundant and widespread mammal in this Park.
Capture rates of honey possums were significantly related to the years since the vegetation was last burnt, annual rainfall in the preceding (but not the current) year, the season when trapping occurred, and the trapping grid operated. Capture rates declined markedly after fire and remained low (less than one third of those in long unburnt vegetation) for about 4 - 5 years following a fire. Rates of capture then increased steadily over the next 20 - 25 years, with maximal abundance recorded about 30 years after fire. Thereafter, there appeared to be a slight decline in capture rates, but even in the vegetation unburnt for longest (> 50 years since fire), honey possum abundance was substantial and relatively stable. In contrast to these changes in abundance, the structure of the honey possum population, with 79 % adults and 57 % males, appeared little influenced by fire history, annual rainfall, season or grid.
The increase in the rates of capture of honey possums following fire paralleled the pattern of availability of cover in the vertical and, to a lesser extent, horizontal plane. Indeed, projective foliage cover took around 20 years after fire to reach levels similar to those available in areas unburnt for even longer. The trend in capture rates was also congruent with the maturation of the most frequently visited foodplants of honey possums, particularly Banksia nutans (summer flowering) and B. baueri (winter flowering). Areas long unburnt still contained shelter and foodplants adequate for honey possums even 50 years or more after fire, with only slight evidence of senescence.
Pollen loads indicated that honey possums caught in burnt areas, where their preferred foodplants were absent, continued to feed on these favoured foodplants (Banksia and Dryandra spp.) at nearby unburnt areas. In addition, they also fed, in both burnt and long unburnt areas, upon a suite of other plant species that regenerated more rapidly from lignotubers and epicormic buds, as well as from seeds (e.g. Eucalyptus and Calothamnus spp.). Thus, honey possums appeared to persist with their preferences for feeding from a limited number of flowering plants despite some of these species not being available in recently burnt areas for many years. Nearby patches of unburnt vegetation can clearly be important refuges, feeding grounds and shelter for the few honey possums that visit recently burnt areas, and appear to be the source of honey possum colonists in the years following a fire.
Capture rates were also greater following years when rainfall was higher than average. Indeed, rainfall had as great an influence upon capture rates as time since fire. Capture rates were also consistently higher over winter, and to a lesser extent over summer, than in either autumn or spring. Individual grids, even those close together in apparently similar vegetation with a similar fire history, still differed significantly overall in their capture rates of honey possums. This last finding has implications for the use of chronosequences in the study of post-fire changes in biota.
Although not the primary focus of the study, data on the limited suite of other, far less abundant, small mammals present indicated that house mouse Mus musculus domesticus numbers peak soon after fire (about two years after fire), grey-bellied dunnart Sminthopsis griseoventer numbers somewhat later (about eight years after fire) and that southern bush rats Rattus fuscipes fiuscipes, like honey possums, are later successional species. Most species were present in vegetation over a range of post-fire ages, with data consistent with models based on sequential changes in relative abundance.
Like many Australian mammals, the range of the honey possum has contracted substantially over the last 200 years and the coastal heathlands of the south-west are its last stronghold. In terms of its conservation, this study indicates that, if possible, management burns in these heathlands should be separated by intervals of at least 20 years between successive burns, and preferably even longer. If burns are required more frequently to meet other management priorities, it is highly preferable that they are small and patchy, rather than large scale. Such practices may help ensure the long-term survival of this unique, highly specialised and endemic marsupial.
17
Bryant, Kate Alexandra. "The mating system and reproduction in the honey possum, Tarsipes rostratus: a life-history and genetical perspective." Thesis, Bryant, Kate Alexandra (2004) The mating system and reproduction in the honey possum, Tarsipes rostratus: a life-history and genetical perspective. PhD thesis, Murdoch University, 2004. https://researchrepository.murdoch.edu.au/id/eprint/490/.
Анотація:
The honey possum Tarsipes rostratus, a marsupial endemic to South-Western Australia, feeds exclusively upon nectar and pollen. It is one of the smallest marsupials, with adult females (8-12g) significantly larger than adult males (6-9g). Honey possum males have the longest sperm (356 mcg) recorded for any mammaland the testes represent 4.2% body weight, amongst the largest recorded formammal species. These features suggest that sperm competition is an importantpart of the mating system. This study used a combination of field based studies,DNA analysis and histological examination of the female reproductive tract toinvestigate the life history, multiple paternity and reproduction of the honey possum innatural populations in the Fitzgerald River National Park (FRNP), on the south coastof Western Australia.
This study drew upon earlier work on the honey possum in the FRNP in order to describe its life-history. The honey possum is short-lived (1-2 years), and attains sexual maturity whilst still growing. All four teats are occupied after birth, but the litter is reduced to 2 or 3 young during pouch life. The young have a relatively slow rate of growth. Breeding occurs continuously throughout the year, but is affected by the flowering phenologies of its foodplants. The greatest proportion of females with pouch-young occurs in winter; there are fewest pouch-young in autumn, a time of year when there is a dearth of flowers. Honey possums are essentially solitary animals, with no structured social unit, and male and female home ranges overlap. In captivity they are largely tolerant of one another, but larger females are behaviorally dominant to smaller females and to males.
The densities and structure of the honey possum populations in the FRNP were analyzed from trapping data collected over 19 years. Population densities fluctuated significantly from season to season throughout the year, with changes in the flowering food resources available. There were also year-to-year differences in the intensity of those fluctuations, and these were significantly associated with rainfall in the previous year, and probably mediated through a lag effect in the flowering of the honey possum's foodplants. The greatest densities of animals occurred over winter. In years following high rainfall, mean winter densities reached 88 individuals per hectare. The lowest densities occurred in spring, and in years following low rainfall mean spring densities fell to 8 individuals per hectare. Even at these lowest densities, there is still the potential for interaction between males and females. A succession from high to low, then back to high densities was seen during the three years of the present study (2000-2002) and this shadowed a similar succession of changes in rainfall.
The proportion of females with pouch-young was significantly affected by the season, and by rainfall in the previous year. Years following low rainfall had a lower proportion of females in a condition to breed. The autumn dip in breeding that occurred in all years was exacerbated following dry years. Of those females that did breed in 2001, a time of low resources, there was no difference in the size of the litter compared to 2000 and 2002, times of higher resource availability. The sex-ratio of pouch young was at parity, but there was a slight bias towards males among both juveniles (56%) and adults (58%). This was probably due to the greater movements shown by males. Sex ratios were not affected by changes in rainfall and density. Male-biased dispersal was detected using genetic data and the movement patterns of males showed that they moved greater distances than females during their normal activity.
Analysis of four microsatellite loci revealed extremely high levels of variation, with 28 to 50 alleles per locus and a mean expected heterozygosity of 0.95. These are amongst the highest seen in any microsatellite study of vertebrates. There was multiple paternity in 86% litters, using a minimum number of sires per litter method, and in 95% litters, using an estimated number of sires method based upon the relatedness of litter males. This indicates that multiple mating is frequent in female honey possums and is evidence for sperm competition. The estimated number of sires in a litter was often three or four. In 41% of cases, the number of sires was less than the number of young in the litter, indicating that some males were more successful at siring offspring than others. Nevertheless, no more than two offspring in a litter were known to have been sired by the same male. Despite marked fluctuations in density from high in 2000, to low in 2001, then high again in 2002, the level of multiple paternity remained equally high in all years.
Embryonic diapause and female reproduction was investigated in the honey possum. All adult females examined, both with and without pouch-young, were either close to oestrus, had ovulated or were carrying conceptuses. The honey possum has a postpartum oestrus and it was evident that this occurs approximately 2-4 days after birth. Cleavage and formation of the unilaminar blastocyst appears to occur rapidly over approximately 5 days. Embryonic diapause proceeded in a two phase manner similar to other small possum species. The unilaminar blastocyst expanded rapidly at first; and then, from about 18-20 days after birth, the diameter of the blastocyst remained constant at approximately 1.2-1.8mm. No growth or development beyond the unilaminar stage was observed during pouch-life. The first signs of reactivation occurred during lactation, after pouch exit, and expansion of the blastocyst only occurred in one post-lactational female. The development of the corpus luteum appeared different to patterns described for other marsupials, but its formation coincided with the formation of the unilaminar blastocyst. The diameter of the corpus luteum remained constant throughout diapause. The histology of the reproductive tract was generally similar to other marsupials. There were no sperm storage crypts in the female reproductive tract.
The length of pouch-life in the honey possum was 55-65 days, and the interval between litters of the same size varied between 65 and 100 days. Embryonic diapause may reduce the time between production of successive litters in the honey possum, but lifetime reproductive potential is reasonably low. Females had up to four litters over the period that they were captured. Thus, each litter represents a substantial proportion (25%) of a female's lifetime reproductive output. Reproductive amortization occurred, with 61% loss overall, due to overproduction of ova, loss of conceptuses and reduction of the litter during lactation.
The behavioural dominance of females suggests that multiple mating is an active strategy, and this presumably allows the genetic quality of their offspring to be maximized. Males that succeed in sperm competition may be of better intrinsic quality. Overproduction of conceptuses by females presents the opportunity for them to select those fertilized by intrinsically viable males or genetically compatible males. Sexually active males are present all year round. Females were not synchronous in their sexual receptivity, and this would lead to a skewed operational sex ratio, with more reproductive males than oestrous females. Since adult males are significantly smaller than adult females and possess no ornaments or armaments, it is unlikely that males overtly fight for access to females. Rather, males appear to monitor the reproductive status of females through smell, and probably compete in their ability to locate oestrous females. The risk and intensity of sperm competition is high, sexual selection for a large investment in spermatogenesis is evident and competition after copulation is probably an important factor in the mating system. It is likely that males, as well as females mate multiply, and the mating system is promiscuous.
18
Bryant, Kate Alexandra. "The mating system and reproduction in the honey possum, Tarsipes rostratus : a life-history and genetical perspective /." Bryant, Kate Alexandra (2004) The mating system and reproduction in the honey possum, Tarsipes rostratus: a life-history and genetical perspective. PhD thesis, Murdoch University, 2004. http://researchrepository.murdoch.edu.au/490/.
Анотація:
The honey possum Tarsipes rostratus, a marsupial endemic to South-Western Australia, feeds exclusively upon nectar and pollen. It is one of the smallest marsupials, with adult females (8-12g) significantly larger than adult males (6-9g). Honey possum males have the longest sperm (356 mcg) recorded for any mammaland the testes represent 4.2% body weight, amongst the largest recorded formammal species. These features suggest that sperm competition is an importantpart of the mating system. This study used a combination of field based studies,DNA analysis and histological examination of the female reproductive tract toinvestigate the life history, multiple paternity and reproduction of the honey possum innatural populations in the Fitzgerald River National Park (FRNP), on the south coastof Western Australia.
This study drew upon earlier work on the honey possum in the FRNP in order to describe its life-history. The honey possum is short-lived (1-2 years), and attains sexual maturity whilst still growing. All four teats are occupied after birth, but the litter is reduced to 2 or 3 young during pouch life. The young have a relatively slow rate of growth. Breeding occurs continuously throughout the year, but is affected by the flowering phenologies of its foodplants. The greatest proportion of females with pouch-young occurs in winter; there are fewest pouch-young in autumn, a time of year when there is a dearth of flowers. Honey possums are essentially solitary animals, with no structured social unit, and male and female home ranges overlap. In captivity they are largely tolerant of one another, but larger females are behaviorally dominant to smaller females and to males.
The densities and structure of the honey possum populations in the FRNP were analyzed from trapping data collected over 19 years. Population densities fluctuated significantly from season to season throughout the year, with changes in the flowering food resources available. There were also year-to-year differences in the intensity of those fluctuations, and these were significantly associated with rainfall in the previous year, and probably mediated through a lag effect in the flowering of the honey possum's foodplants. The greatest densities of animals occurred over winter. In years following high rainfall, mean winter densities reached 88 individuals per hectare. The lowest densities occurred in spring, and in years following low rainfall mean spring densities fell to 8 individuals per hectare. Even at these lowest densities, there is still the potential for interaction between males and females. A succession from high to low, then back to high densities was seen during the three years of the present study (2000-2002) and this shadowed a similar succession of changes in rainfall.
The proportion of females with pouch-young was significantly affected by the season, and by rainfall in the previous year. Years following low rainfall had a lower proportion of females in a condition to breed. The autumn dip in breeding that occurred in all years was exacerbated following dry years. Of those females that did breed in 2001, a time of low resources, there was no difference in the size of the litter compared to 2000 and 2002, times of higher resource availability. The sex-ratio of pouch young was at parity, but there was a slight bias towards males among both juveniles (56%) and adults (58%). This was probably due to the greater movements shown by males. Sex ratios were not affected by changes in rainfall and density. Male-biased dispersal was detected using genetic data and the movement patterns of males showed that they moved greater distances than females during their normal activity.
Analysis of four microsatellite loci revealed extremely high levels of variation, with 28 to 50 alleles per locus and a mean expected heterozygosity of 0.95. These are amongst the highest seen in any microsatellite study of vertebrates. There was multiple paternity in 86% litters, using a minimum number of sires per litter method, and in 95% litters, using an estimated number of sires method based upon the relatedness of litter males. This indicates that multiple mating is frequent in female honey possums and is evidence for sperm competition. The estimated number of sires in a litter was often three or four. In 41% of cases, the number of sires was less than the number of young in the litter, indicating that some males were more successful at siring offspring than others. Nevertheless, no more than two offspring in a litter were known to have been sired by the same male. Despite marked fluctuations in density from high in 2000, to low in 2001, then high again in 2002, the level of multiple paternity remained equally high in all years.
Embryonic diapause and female reproduction was investigated in the honey possum. All adult females examined, both with and without pouch-young, were either close to oestrus, had ovulated or were carrying conceptuses. The honey possum has a postpartum oestrus and it was evident that this occurs approximately 2-4 days after birth. Cleavage and formation of the unilaminar blastocyst appears to occur rapidly over approximately 5 days. Embryonic diapause proceeded in a two phase manner similar to other small possum species. The unilaminar blastocyst expanded rapidly at first; and then, from about 18-20 days after birth, the diameter of the blastocyst remained constant at approximately 1.2-1.8mm. No growth or development beyond the unilaminar stage was observed during pouch-life. The first signs of reactivation occurred during lactation, after pouch exit, and expansion of the blastocyst only occurred in one post-lactational female. The development of the corpus luteum appeared different to patterns described for other marsupials, but its formation coincided with the formation of the unilaminar blastocyst. The diameter of the corpus luteum remained constant throughout diapause. The histology of the reproductive tract was generally similar to other marsupials. There were no sperm storage crypts in the female reproductive tract.
The length of pouch-life in the honey possum was 55-65 days, and the interval between litters of the same size varied between 65 and 100 days. Embryonic diapause may reduce the time between production of successive litters in the honey possum, but lifetime reproductive potential is reasonably low. Females had up to four litters over the period that they were captured. Thus, each litter represents a substantial proportion (25%) of a female's lifetime reproductive output. Reproductive amortization occurred, with 61% loss overall, due to overproduction of ova, loss of conceptuses and reduction of the litter during lactation.
The behavioural dominance of females suggests that multiple mating is an active strategy, and this presumably allows the genetic quality of their offspring to be maximized. Males that succeed in sperm competition may be of better intrinsic quality. Overproduction of conceptuses by females presents the opportunity for them to select those fertilized by intrinsically viable males or genetically compatible males. Sexually active males are present all year round. Females were not synchronous in their sexual receptivity, and this would lead to a skewed operational sex ratio, with more reproductive males than oestrous females. Since adult males are significantly smaller than adult females and possess no ornaments or armaments, it is unlikely that males overtly fight for access to females. Rather, males appear to monitor the reproductive status of females through smell, and probably compete in their ability to locate oestrous females. The risk and intensity of sperm competition is high, sexual selection for a large investment in spermatogenesis is evident and competition after copulation is probably an important factor in the mating system. It is likely that males, as well as females mate multiply, and the mating system is promiscuous.
19
Wallis, John Craig. "3-hydroxycineole, possum metabolites of 1,8-cineole /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19352.pdf.
20
Sekkel, Marie Claire. "A construção de um ambiente inclusivo na educação infantil: relato e reflexão sobre uma experiência." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/47/47131/tde-09122013-082848/.
Анотація:
Esta tese estuda as determinações presentes no processo de inclusão de crianças com necessidades educacionais especiais, a partir da experiência desenvolvida na Creche Oeste, que pertence à Coordenadoria de Assistência Social da Universidade de São Paulo - COSEAS/USP. Enfoca o processo de inclusão do ponto de vista dos educadores/funcionários e das crianças. Foi utilizada a abordagem etnográfica, para a qual serviram como fonte vários registros institucionais, conversas informais, e depoimentos individuais e grupais, colhidos junto aos educadores/funcionários e estagiários que participaram do processo. Os relatos evidenciam o medo, que está presente e contribui para a manutenção de preconceitos e estereótipos. Esse medo é grande, e não pode ser enfrentado de forma isolada; é necessário criar um ambiente inclusivo, a partir de princípios democráticos, os quais precisam ser discutidos e consentidos nas situações concretas, ao longo do processo de (re)construção do projeto educacional. Este trabalho enfatiza a necessidade de abertura à experiência, essencial a uma educação que tem como objetivo as finalidades humanas.não possui
21
Mauro, Patricia Izar. "Análise da estrutura social de um grupo de macacos-prego (Cebus apella) em condições de semi-cativeiro." Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-04122013-140542/.
Анотація:
Considera-se que a estrutura social de grupos selvagens de Cebus apella é caracterizada por hierarquia de dominância linear que determinaria uma organização espacial rígida dos membros do grupo em função da exploração de recursos alimentares e da vigilância do grupo. Um grupo da espécie, mantido em semi-cativeiro, cuja composição variou entre 40 e 47 indivíduos. foi estudado a fim de descrever sua estrutura social, e verificar a coesão entre os membros de um grupo formado artificialmente e o grau de alteração que as condições de manutenção, com alimento abundante e ausência de predadores, poderiam estar provocando sobre a organização social. Foi possível descrever relações de dominância e organização espacial semelhantes às descritas para grupos naturais apenas para o período de fornecimento de alimentação no cocho. Durante o restante do dia a pressão de competição por alimento sobre a estrutura social do grupo estava relaxada e foram observadas intensas relações afiliativas entre os indivíduos. As relações sociais estabelecidas pelos diferentes membros do grupo podem ser entendidas como estratégias para aquisição de aliados, aumento de potencial reprodutivo e aquisição de competência social, de acordo com sexo, idade e posição hierárquica dos indivíduos envolvidos.Wild groups of Cebus apella are distinguished by a linear dominance hierarchy which determines a non-random spatial organization of the group members, in terms of the exploitation of ood resources and the advantages of group vigilance. A semi-captive artificialy formed group of this species, with a composition varying between 40 and 47 individuais, was studied to describe the social structure, investigate the cohesion of the group members,and verify possible consequences resulting ftom captive conditions, involving abundant food and an absence of predators, on its social organization. Dominance relationships and spatial organization were similar to that described for wild groups only at the moment when food was supplied. During the rest of the day the significance of food competition for the social structure of the group was relaxed, and strong affiliative relationships were observed. The relationships estabilished between different group members could be understood as strategies for the acquisition of allies, enhancing reproductive opportunities and the development of social skills, according to sex, age and dominance status of the individuais involVed.
22
Ottoni, Eduardo Benedicto. "Dos limites de contar ao contar sem limites: um estudo sobre o desenvolvimento da competência número e da noção de infinitude na criança." Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-09102013-145145/.
Анотація:
Observamos o desenvolvimento, em crianças de 3 a 12 anos, de comportamentos relacionados à compreensão do número. Foram analisados parâmetros relativos ao desempenho em tarefas de contagem, traduzidos em valores-limite de proficiência no contar, erros de contagem e de correspondência 1-a-1, uso de resposta cardinal e conservação do número. Outras perguntas verificaram os maiores nomes de números conhecidos, a compreensão da infinitude do número e o desempenho em tarefas de estimação de \"grandes quantidades\". Outros testes visaram explorar a compreensão de grandezas ou processos infinitos (Duração infinita, Ciclicidade, Subdivisão infinita e Limite) e as definições e exemplos fornecidos para o termo \"infinito\". As correlações entre as variáveis mostram que o desempenho no contar é um forte indicador do desempenho nos outros aspectos. Os resultados favorecem o ponto-de-vista das teorias sobre compreensão do número \"baseadas no contar\". Duas transições importantes foram observadas: a primeira referente ao contar além de 20 (domínio da base 10), a segunda relativa ao contar até mais de mil (domínio da \"superbase\" mil). A primeira se mostrou significativamente associada ao desaparecimento de erros de correspondência 1-a-1 e ao estabelecimento da resposta cardinal; a segunda, à consolidação da conservação, à compreensão de que os números naturais são infinitos e ao desenvolvimento da compreensão do conceito de infinitude.We observed the development (in children from 3 to 12 years old) of behaviors related to the understanding of number. The parameters analysed included the performance in counting tasks - translated into limit-values of proficiency -, counting and one-one correspondence errors, cardinal response usage, and number conservation. Other questions verified the largest number names known, the comprehension of the infinity of number and the performance in in tasks involving the estimation of \"large quantities\". Other tasks aimed to explore the understanding of infinite magnitudes or processes (Infinite Duration, Cyclicity, Infinite Subdivision, and Limit), as well as the definitions and examples provided for the word \"infinity\". The correlations between variables show that the counting performance is a strong predictor of performance in the other topics. Results favor the standpoint of \'based on counting\" theories on number comprehension. Two important transitions were observed: the first one refers to counting beyond 20 (understanding of base 10), the second one, to counting beyond one thousand (the \"superbase\" 1000). The former is significantly associated to the disappearance of one-one correspondence errors and to the establishment of cardinal response; the latter, to the consolidation of conservation, to the comprehension that natural numbers are infinite, and to the development of the concept of infinity.
23
Mauro, Patricia Izar. "Aspectos de Ecologia e Comportamento de um Grupo de Macacos-Prego (Cebus Apella) em Área de Mata Atlântica, São Paulo." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-19112013-151852/.
Анотація:
Visando analisar a relação entre variáveis ecológicas e comportamento de C. apella, foi estudado um grupo da espécie no Parque Estadual Intervales, SP, de abril de 1995 a dezembro de 1997. Foram registrados: parâmetros climáticos e de oferta de frutos maduros no habitat, o comportamento dos animais em resposta à presença de observadores humanos, dieta e dispersão de sementes pelos animais através da análise de amostras fecais, padrões de comportamento locomotor - tamanho da área de uso, variação mensal do tamanho da área explorada e frequência de visitas a sub-áreas da área de uso. Os animais do grupo estudado não se habituaram à presença de observadores humanos, apresentando respostas de fuga e alarme durante os trinta e três meses de pesquisa, o que foi creditado à associação entre variabilidade individual de temperamento, aprendizagem anterior e características topográficas da área. A dieta dos animais constituiu-se principalmente de polpa de frutos maduros e em meses com menor oferta de frutos, bromélias furam o principal recurso alternativo. O tamanho da área de uso do grupo fui relacionado à massa de frutos maduros disponível no habitat. Em meses com menor oferta de frutos os animais expandiram ou diminuíram o tamanho da área explorada de acordo com a distribuição dos recursos alimentares alternativos. A frequência de utilização de sub-áreas não se relacionou com parâmetros de oferta de frutos. Os animais foram considerados dispersores importantes de espécies de plantas cujos frutos foram utilizados na dieta, mas a dispersão foi limitada pelo diâmetro das sementes. A reação a observadores humanos e os padrões de comportamento locomotor observados indicam a variabilidade comportamental da espécie, adaptando-se às características do habitat.Analyses lhe relationships between ecological variables and behaviour of a C. apella group, in Parque Estadual Intervalos, SP, from April. 1995 to December, 1997. Data were recorded from climatic parameters, and fruit availability in lhe habitat, animals´ response to human observers, animals\' diet and seed dispersion examined trough faecal sample analysis, patterns of ranging behaviour, home range, monthly variation of home range use, and frequency of use of home range sub-areas. The study group did not habituate to human observers after thirty-three months of research. This pattern of response is probably related to individual variability of temperament, past learning, and habitat features. The animais fed mostly on mature fruits pulp, and fed heavily on bromeliads in months with minor mature fruit offer. Home range size was related to fruit mass availability. In months with less fruit, the study group expanded or reduced home range size according to lhe pattern of distribution of alternative food sources. The frequency at which lhe animais used different sub-areas of home range was not related to fruit offer. C. apella can be considered an important seed disperser of plant species they fed in; but seed dispersion is constrained by seed diameter. The patterns of reaction to human observers and of ranging behaviour indicate behavioural variability of C. apella, according to habitat features.
24
Massola, Gustavo Martineli. "Sistema Penitenciário: Reforma ou Reprodução. Um Estudo da APAC São José dos Campos." Universidade de São Paulo, 2001. http://www.teses.usp.br/teses/disponiveis/47/47134/tde-07112013-141242/.
Анотація:
Este trabalho tem por objetivo descrever e analisar as práticas estabelecidas por uma instituição penal reformada dirigida por uma ONG: a APAC (Associação de Proteção e Assistência aos Condenados) de São José dos Campos- São Paulo, a fim de se estabelecer seu papel institucional frente ao restante do sistema penal e buscar uma explicação para seu recente fechamento pelo Judiciário. Para tanto, foi desenvolvida uma pesquisa etnográfica em suas dependências. Além disso, foram coletados documentos produzidos pela própria instituição e foram realizadas oito entrevistas, sendo seis com voluntários e duas com egressos da instituição. As razões para o fechamento parecem estar ligadas ao valor econômico que foi atribuído às transferências dos presos da comarca para a APAC, o que reduziu o poder institucional sobre os presos.Describes and analyses lhe practices established by a \"reformed\" penal institution: APAC (Association for Protection and Assistance of lhe Prisoners) from São José dos Campos - São Paulo, in order to examine its institutional role in face of the Brazilian penal system and also in order to explain its closure. This study made use of the etbnographic method and we also collected documents produced by lhe institution. Besides, we took eight interviews (six from volunteer workers and two from ex-convicts). The convicts transference to the institution became economically valuable in late years, what seems to explain its closure.
25
Clarke, Judith Rebekah. "Translocation outcomes for the Western Ringtail Possum (Pseudocheirus occidentalis) in the presence of the Common Brushtail Possum (Trichosurus vulpecula): health, survivorship and habitat use." Thesis, Clarke, Judith Rebekah (2011) Translocation outcomes for the Western Ringtail Possum (Pseudocheirus occidentalis) in the presence of the Common Brushtail Possum (Trichosurus vulpecula): health, survivorship and habitat use. PhD thesis, Murdoch University, 2011. https://researchrepository.murdoch.edu.au/id/eprint/5119/.
Анотація:
The western ringtail possum, Pseudocheirus occidentalis, is classified as threatened, both nationally and internationally. Land clearing for building development threatens the last major coastal population stronghold in and around the town of Busselton in the south-west of Western Australia (WA). Translocation of displaced P. occidentalis from this locality into nearby conservation estates commenced in 1991, in the presence of fox control, with the aim of re-establishing populations of the species within suitable habitat outside its current range. Initial successes (1991-1998) were followed by a major population decline at one site for unclear reasons. The aim of this project was to determine which factors presently limit translocation success for P. occidentalis and thereby provide direction for future management of the species.
Displaced and rehabilitated P. occidentalis were translocated into three sites, two of which were baited for fox control. Survival was monitored weekly, causes of mortality were ascertained and attributes of habitat use were mapped and analysed. Each individual P. occidentalis underwent comprehensive health and disease screening under isoflurane anaesthesia prior to translocation and whenever recaptured for re-collaring. Health, survivorship and habitat use of resident common brushtail possums, Trichosurus vulpecula, were similarly studied at each site. Pilot spotlight surveys using line transect methods were performed at the end of the study to provide provisional data on population densities.
Health screening revealed no evidence that infectious disease currently limits translocation success for P. occidentalis. Possums of both species were negative for toxoplasmosis, leptospirosis, salmonellosis and chlamydiosis. Cryptococcal antigen was detected in one individual T. vulpecula but was not of pathological significance. Endoparasite levels were negatively correlated with body condition. Differences between pre- and post-translocation haematological values were found, suggesting that habitat quality or nutrient intake were lower at the translocation sites than at the sites of origin.
Mortality rates of translocated P. occidentalis were high. The majority of P. occidentalis deaths were attributed to predation, with foxes, cats, pythons and raptors all implicated. Some P. occidentalis died in poor body condition from apparent hypothermia/hypoglycaemia, with moderate to heavy parasite burdens present at necropsy. Most T. vulpecula mortality was attributable to fox predation. Survivorship analyses were carried out using information-theoretic techniques to investigate which, if any, of a suite of hypothesised factors most influenced post-translocation survival of P. occidentalis. The most highly ranked models were those that included pre-release white blood cell counts and/or numbers of T. vulpecula at the release site. Survivorship of P. occidentalis was negatively correlated with each of these factors, and the two together acted in a synergistic fashion. Effects of fox control on P. occidentalis survivorship were equivocal. The average annual survival rate of established P. occidentalis was less than half that of resident T. vulpecula.
Post-translocation dispersal distances varied among individual P. occidentalis. Mean home range sizes of translocated P. occidentalis were larger than those reported for other coastal populations. Individual home ranges overlapped one another, both within and between possum species. Vegetation dominated by peppermint (Agonis flexuosa) was utilised by translocated P. occidentalis where available, and habitat partitioning between the two possum species was observed in some areas. A greater range of diurnal rest site types were utilised by P. occidentalis than T. vulpecula. Spotlight surveys revealed presence of low density P. occidentalis populations, including juveniles, at two sites but numbers remained negligible in the site at which the post-1998 decline had occurred.
Complex interactions involving health, predation, habitat quality and inter-specific competition influence the success or otherwise of wildlife translocation programs. The results of this project suggest that all these factors, particularly predation, affected translocation outcomes for P. occidentalis during the period of study. Complete exclusion of exotic predators (foxes and cats) from the translocation sites may be necessary in future, especially given the numbers of native predators (pythons and raptors) present. In addition to heavy predation pressure, the small size and apparently low carrying capacity of the translocation sites for P. occidentalis, along with high numbers of resident T. vulpecula, currently appears to limit P. occidentalis survival and population growth.
While, in the short term, the most efficient use of funds and the best option for the species in its current coastal strongholds might be to put greater effort into conserving P. occidentalis in its natural environment, there could also be value in carrying out further experiments to determine whether or not translocation success can be improved through use of particular management actions. The principles of adaptive management apply both to management of P. occidentalis in its natural environment and to conduction of translocation programs. Possible experimental approaches are outlined and recommendations for further research proposed.
26
de, Zwart Eykolina Jacoba. "Possum resource selection in a fragmented landscape, Cass, New Zealand." Thesis, University of Canterbury. Forestry, 2002. http://hdl.handle.net/10092/8566.
Анотація:
This study presents the results of an investigation to determine the resources utilised by possums in a spatially heterogeneous landscape in the Canterbury high country. The study area comprised a mosaic of forest, scrub, shrubland, grassland and swamp at the University of Canterbury field station at Cass, inland Canterbury.
The vegetation communities at Cass were originally divided into seven different categories based on species composition. These areas are referred to as the swamp, grassland, shrubland, scrub1, scrub 2, native forest, and exotic forest. Communities were classified using two multivariate techniques; TWINSPAN and Detrended correspondence analysis. A vegetation map of Cass was produced using ground survey and aerial maps, and displayed the extent and coverage of vegetation communities. These vegetation communities reflect the influence of burning and farming. The study area comprises c. 195 ha.
The overall possum density was low, with approximately one possum per hectare. This result may be due to resources that possums need for survival, being deficient in the area.
Possum movements were investigated by radio-collaring six female possums and six male possums at Cass. These possums were radio-tracked six times during a period of ten months, with each radio-tracking session undertaken for a period of three consecutive nights. The data collected were used to derive individual home ranges using Minimum Convex Polygon and Kernel home range estimates. There was no statistically significant difference between female and male home ranges at Cass. No seasonal difference in possum home range was detected, although other possum home range studies have found seasonal differences. There were too few den site location areas to enable accurate information concerning seasonal variation of den sites. Possums had relatively large home ranges, which probably result from a low possum density in the areas, as well as spatial heterogeneity of key resources. Nine possums showed some degree of home range overlap, but there did not appear to be any difference between females and males with respect to this. Sixty percent of the possums studied exhibited bimodal home ranging behaviour. Bimodal behaviour almost certainly results from the spatial heterogeneity of key resources, with possums having to travel long distances in order to use all the resources.
Possum diet was assessed using a point sampling technique, which identifyied all ingested stomach material greater than 3mm, at four times through 2001. There was no statistical difference between female and male diet, or between juvenile and adult diet. Thirty-eight different food items were consumed by possums over the study period, with four dominant food items that comprised of 50% of their diet (Aristotelia fruticosa, fungi, Podocarpus nivalis, and Blechnum penna-marina).
Due to the spatial heterogeneity of vegetation communities at the Cass study area, possums utilised the different habitats non-randomly, preferring the scrub and forest communities.
Possum management is not currently needed at Cass, although in the future, if possum density increases than management options should be reassessed in order to minimise possum impact.
27
Horner, Briony. "The importance of Banksia marginata and Banksia ornata as a food source for Cercartetus concinnus (the western pygmy-possum) and Cercartetus lepidus (the little pygmy-possum) /." Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09AEVH/09aevhh816.pdf.
28
Sessions, Laura A. "Monitoring leaf loss and possum impact on New Zealand beech mistletoes." Thesis, University of Canterbury. Botany, 1999. http://hdl.handle.net/10092/6874.
Анотація:
Numerous anecdotal reports have suggested that possums are the primary cause of mistletoe decline throughout New Zealand, but little quantitative data has been collected to support this claim. The primary goal of this study was to quantitatively assess the annual amount of lea floss due to possum herbivory, insect herbivory, and leaf abscission on two populations of each of three endemic mistletoe species (Alepis flavida, Peraxilla colensoi, and P. tetrapetala) in four South Island beech forests (Craigieburn, Lake Ohau, Eglinton Valley, and Waipori Gorge). In all six populations, from February 1997 to February 1998, abscission accounted for by far the most leaf loss (range 10-84%, mean 33%), while insects and possums contributed to the mean loss of less than 3% of total leaf area across all six populations. Although possums and insects overall removed similar amounts of plant biomass, possum browse was significantly more heterogeneous than insect browse both on branches within a plant (possum c.v.=2.63, insect c.v.=1.94) and between plants in a population (possum c.v.=2.74, insect c.v.=1.17). Moreover, insects damaged all study plants but removed less than 9% of leaf area per plant, while possums only browsed 32% of the study plants but severely defoliated some plants. Mean leaf loss was significantly greater on plants browsed by possums (62%) than on unbrowsed plants (36%). Thus, while insect damage probably constitutes a predictable stress for most plants, possum browse is unpredictable and may cause a small increase in mortality of affected mistletoes, which could cause a slow decline at the population level for plants with long life-spans and slow reproductive rates.
The second goal of this study was to compare the effectiveness of three commonly used methods of monitoring mistletoes: leaf mapping, visual estimates of plant health (i.e. percent browse scores, foliage density scores, and volume measurements), and photographs. Leaf maps provided the most detailed description of leaf loss but are too laborious to be used on a national scale. Visual estimates were subjective, did not correlate to quantitative leaf map data, and failed to detect the loss of branches. Foliage loss estimated from an examination of repeated photographs corresponded extremely well to leaf loss estimates from leaf maps. A monitoring protocol is suggested that includes photographing mistletoes every winter and visually estimating possum browse each winter and summer.
29
Chen, Li-Wen. "What skills do star fund managers possess?" Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/7812.
Анотація:
Kosowski, Timmermann, Wermers, and White (2006) find that certain growth-oriented fund managers have substantial skill but do not stipulate the particular skills that they possess. I use novel style timing models to examine in detail the timing skills of 3,181 US equity mutual funds classified as having a growth investment objective by Standard & Poor’s, over the period from 1993 to 2006. To control for idiosyncratic variation in mutual fund returns, the bootstrap method of Kosowski et al. is used to analyze the significance of alpha and timing coefficient estimates. To exclude the possibility that the observed timing ability is due to good luck, synthetic funds are examined as in Busse (1999). The results indicate that growth-oriented fund managers who earn abnormal returns demonstrate substantial growth timing skill, i.e. successful timing activity across the value/growth continuum. This observed growth timing ability accounts for at least 45% of abnormal returns and is persistent; the top 10% of funds which demonstrate growth timing ability in the past three years also demonstrate the best growth timing ability in the following year. Successful growth timing is confined to those managers who invest primarily in growth stocks. However, there is little evidence of successful market timing (i.e. forecasting future market states and weighting equity exposure accordingly), size timing (i.e. adjusting exposure between small and large capitalization stocks) or momentum timing (i.e. switching between momentum investing and contrarian investing strategies). The models employed clearly distinguish between growth timing and market timing skills, thereby avoiding a common misidentification problem.
30
God, Jason Matthew. "Red raspberries possess anticarcinogenic and immunostimulatory potential." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1252424290/.
31
Head, Nicholas. "The impacts of possum herbivory and possum control on threatened palatable species (Pittosporum patulum, Alepis flavida and Peraxilla tetrapetala) in the Lake Ohau Catchment, South Island, New Zealand." Lincoln University, 2005. http://hdl.handle.net/10182/1957.
Анотація:
The impacts of possum herbivory were assessed on 713 individual plants of the nationally endangered Pittosporum patulum and 115 individual plants of the threatened ('Gradual Decline') mistletoes (Alepis flavida & Peraxilla tetrapetala) over three years in the Temple and Huxley river valleys in the Ohau catchment, South Island New Zealand. Statistical models were used to test the influence of several explanatory variables on the probability of survival and growth rates of these rare palatable plants. Increasing defoliation levels were the most significant predictors of mortality for both P. patulum and mistletoe, and reduced growth rates in P. patulum. Mortality of P. patulum increased with plant size although smaller plants were also affected by mortality. P. patulum mortality was greater for non-forest habitats, and growth rates were greatest on warm aspects. Mistletoe mortality increased with warm aspect, steeper slopes and at lower altitudes. Plant survival and growth increased in the Temple valley following possum control. Although indicative of a positive treatment effect, other factors may have also influenced this result. Possums are the major herbivore responsible for the widespread decline of P. patulum and beech forest mistletoes throughout New Zealand, although the autecology of P. patulum predisposes it toward extinction more so than mistletoe. Monitoring in conjunction with possum control operations provide good opportunities for understanding the impacts of possums on palatable plants and ecosystems. Assessing defoliation levels on indicator species like P. patulum and mistletoes can serve as a guide for managers to assess ecosystem stress from herbivory.
32
McDowell, Arlene, and n/a. "Oral delivery of bioactive compounds to the common brushtail possum (Trichosurus vulpecula)." University of Otago. School of Pharmacy, 2005. http://adt.otago.ac.nz./public/adt-NZDU20070306.151503.
Анотація:
The common brushtail possum (Trichosurus vulpecula) is the most significant vertebrate pest in New Zealand as an ecological threat to the indigenous biodiversity and an economic threat as a vector for bovine tuberculosis. Biological control is considered to be the most accepted management strategy to reduce the population, specifically by impairing fertility. Successful development of a biocontrol agent (most likely a protein or peptide macromolecule) requires identification of a compound that is species-specific and potent. The challenge is also to deliver the bioactive to this free-ranging, widespread, feral animal and ensure sufficient bioavailability. Macromolecules have low oral bioavailability, thus new formulation strategies are required to enhance stability and absorption in the gastrointestinal tract (GIT) of T. vulpecula. Oral administration of the bioactive contained within a non-toxic bait is the most practical delivery strategy.
Essential to designing an oral delivery system is to quantify the transit time of different sized delivery systems. The gastrointestinal transit in T. vulpecula was investigated (n = 72) by gamma scintigraphy. Technetium-labelled (99mTc) anion exchange resin particles (75 - 125 (mu)m or 500 - 700 (mu)m) or solution (99mTc-DTPA) was administered orally. After 3, 6, 12, 24 or 32 h, distribution of radioactivity in excised GITs was determined. Transit profiles were similar for each formulation. For delivery to the hindgut, bioactives need protection for 12 h though the upper GIT. Particulate formulations may be retained in the caecum for up to 32 h. Transit time was not different between animals dosed in the evening or the morning. Furthermore, GIT morphology is different between specimens in this study from southern New Zealand and Australian specimens. This may reflect improved diet quality in New Zealand.
A model protein (insulin) was incorporated into poly(ethyl 2-cyanoacrylate) (PECA) nanoparticles prepared by interfacial polymerisation of water-in-oil microemulsions. The mean size of nanoparticles was 220 nm with a mean entrapment efficiency of 78%, determined using reverse phase HPLC. In vitro release of insulin from PECA nanoparticles in phosphate buffer (0.067 M, pH 7.4) at 37°C was triphasic and not all entrapped insulin was released.
Following in vitro incubation of nanoparticles with enzyme solutions prepared from the GIT of T. vulpecula, lumen enzymes were more aggressive towards insulin compared to mucosal enzymes and the hindgut lumen was the GIT region with the lowest degradation.
For the first time in a marsupial species, the in vivo pharmacokinetics of insulin-loaded, PECA nanoparticles were investigated following i.v. and intra-caecal administration and measured by radioimmunoassay. The low cross reactivity of human and endogenous brushtail possum insulin means that T. vulpecula is a suitable non-diabetic model to study pharmacokinetics of insulin. The i.v. pharmacokinetics of insulin solution and insulin-loaded nanoparticles were similar. On intracaecal dosing, co-administration of a permeation enhancer (EDTA) resulted in a small increase in plasma insulin concentration compared to insulin-loaded nanoparticles alone.
In conclusion, transit time to the caecum of T. vulpecula following oral delivery was 12 h for fluid and particulate formulations < 1 mm diameter and was independent of the time of day the dose was given. T. vulpecula is a potential non-diabetic model for the study of insulin pharmacokinetics. This thesis demonstrates the potential application of oral peptide and protein delivery technology in the area of wildlife management.
33
Ruschke, Alexander [Verfasser], and Otmar [Akademischer Betreuer] Biebel. "POSSuMUS : a position sensitive scintillating muon SiPM detector / Alexander Ruschke. Betreuer: Otmar Biebel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1065610440/34.
34
Owen, Hamish John. "Mistletoe and the brushtailed possum in silver beech forest, South Westland, New Zealand." Thesis, University of Canterbury. Forestry, 1993. http://hdl.handle.net/10092/7027.
Анотація:
The distribution of mistletoe in South Westland silver beech forest was investigated. Stand structure and densities of Peraxilla colensoi (pirita) were assessed along six altitudinal transects. Host size and forest structure were both found to be important factors influencing density and distribution of mistletoe. Generally large beech trees were favoured as mistletoe hosts. There was also significant variation in mistletoe density between forest types.
In a different study the leaf area removed by possums and insects from a population of mistletoe plants was quantified over a nine month period. Insects browsed all plants, and on average consumed around 4% of each mistletoe's leaf area. The overall consumption of mistletoe leaf area by possums was around 2%, but possum browse was not evenly spread over the population. Of the forty plants sampled, seven were attacked by possums with one plant being heavily browsed. By the end of the monitoring period the leaf area retained by possum browsed plants was significantly lower than that of unbrowsed plants. If individual mistletoes continue to be selectively browsed then defoliation and death of some mistletoe plants seems a likely outcome.
Possum diet was assessed by means of gut sample analysis and compared to estimates of food availability within silver beech forest. Possums utilised a wide range of food types but two or three species were dominant at any particular time of the year. Seral species such as wineberry, pohuehue, fuchsia, and lawyer were generally the most important foods. Mistletoe was not an important food item, contributing less than 1% of annual possum diet.
35
Rosa, Andréia Cunha da. "Capacidade absortiva de empresas que possuem interação com universidades." Universidade do Vale do Rio dos Sinos, 2013. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3432.
Анотація:
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Andréia Cunha da Rosa.pdf: 9303233 bytes, checksum: 2bfd02a2657b04794c759e9692f60724 (MD5)Made available in DSpace on 2015-05-05T18:20:49Z (GMT). No. of bitstreams: 1 Andréia Cunha da Rosa.pdf: 9303233 bytes, checksum: 2bfd02a2657b04794c759e9692f60724 (MD5) Previous issue date: 2013-07-30
UNISINOS - Universidade do Vale do Rio dos Sinos
A literatura acadêmica tem destacado importantes contribuições da interação universidade-empresa para o desempenho inovativo das firmas, regiões e países. Entretanto, a literatura aponta, também, alguns determinantes para que essa relação aconteça. Dentre estes determinantes, é apontada a capacidade absortiva das empresas, o que as possibilita adquirir, assimilar, transformar e comercializar os novos conhecimentos adquiridos a partir da relação com as universidades. Tendo em vista a necessidade de uma maior assimilação, distribuição e utilização dos conhecimentos externos relevantes para as empresas, o presente estudo procurou analisar quais são as características da capacidade absortiva das empresas que possuem interação com Universidades. Neste sentido, tal estudo buscou verificar as características e intensidade da capacidade absortiva de empresas que possuem interação com as áreas de Engenharia Mecânica e, de Engenharia de Materiais e Metalúrgica das Universidades gaúchas. Para atingir esse objetivo, foi desenvolvido uma estrutura com indicadores de mensuração da capacidade absortiva. Essa estrutura foi incluída no questionário aplicado em uma survey com empresas inseridas na base do diretório de grupos de pesquisa do CNPq, referente ao censo de 2010, que indicavam algum tipo de interação com as referidas áreas. Para a análise dos resultados foram utilizados métodos estatísticos, tais como, análise de clusters, a fim de agrupar as empresas de acordo com a semelhança do grau de capacidade absortiva. Os principais resultados referem-se à importância da capacidade absortiva para o alcance dos objetivos estabelecidos na interação universidade-empresa, bem como para o seu desempenho inovativo.
The academic literature has highlighted important contributions of university-industry interaction for the innovative performance of firms, regions and countries. However, the literature also points to a number of determinants that relationship happen. Among these determinants, is pointed absorptive capacity of companies, that enables acquire, assimilate, transform and commercialize new knowledge gained from the relationship with universities. Given the need for greater assimilation, distribution and use of external knowledge relevant to business, this study sought to examine what are the characteristics of the absorptive capacity of firms that have interaction with universities. In this sense, this study analyzes characteristics and intensity of the absorptive capacity of firms that have interaction with the Engineering and Mechanics of Materials and Metallurgical Engineering University of Rio Grande do Sul. To achieve this goal, we developed a framework with indicators to measure the absorptive capacity. This structure was included in the questionnaire in a survey of businesses located within the directory of research groups from CNPq, referring to the 2010 census, indicating some interaction with those areas. For the analysis of the results were used statistical methods such as cluster analysis to group firms according to the similarity degree of absorptive capacity. The main results refer to the importance of absorptive capacity to achieve the objectives established in the university-industry interaction, as well as for its innovative performance.
36
Kamenetsky, Margarita. "Mammalian cells possess multiple, distinctly regulated cAMP signaling cascades /." Access full-text from WCMC :, 2006. http://proquest.umi.com/pqdweb?did=1276395511&sid=11&Fmt=2&clientId=8424&RQT=309&VName=PQD.
37
Foulkes, Jeffery Neil, and N/A. "The ecology and management of the common brushtail possum Trichosurus vulpecula in Central Australia." University of Canberra. Applied Science, 2001. http://erl.canberra.edu.au./public/adt-AUC20050411.101222.
Анотація:
This study investigates the ecology of one of the best known Australian marsupials,
the Common Brushtail Possum Trichosurus vulpecula, in central Australia. Trichosurus
vulpecula is one of few medium-sized mammal species that persist in arid Australia today.
Its distribution within the arid zone has declined markedly since European settlement. Two
populations, one within the East MacDonnell Ranges along the Hale River and the other on
Irving Creek, a River Red Gum creek in the Petermann Ranges, were studied in the southern
Northern Territory. Others locations in the region were visited opportunistically. Trie
central Australian Trichosurus is not distinct genetically from populations elsewhere in
Australia.
The diet of T. vulpecula consisted of a range of leaves, flowers and fruits of perennial
dicotyledonous species as well as some ephemeral herbs. Grasses were absent from the diet.
Variation in the diet reflected seasonal availability in flowers and fruits. The species
preferentially consumed at each site had significantly higher moisture content and dry matter
digestibility than species not consumed. Preferred species included Amyema maidenii leaves
(a mistletoe), Acacia spp. flowers and fruits, Santalum lanceolatum leaves (a shrub),
Marsdenia australis leaves (a vine), Solarium quadriloculatum fruit (shrub) and Euphorbia
spp. leaves (herb). Small amounts of invertebrate material were consumed throughout the
year. Other non-plant material consumed included honeycomb and unfledged birds eg.
Budgerigars. There were no significant differences in the diet between the sexes.
Trichosurus vulpecula were found in six main habitats: Acacia aneura/Callitris
glaucophylla on rocky hills; E. camaldulensis sandy creek-lines; mixed Acacia rocky hills,
Rocky Eucalyptus creek-lines; Degraded drainage lines; and Wet gullies. Logistic regression
modelling revealed a significant correlation between mistletoe species richness, higher levels
of soil nitrogen and the presence of T. vulpecula. In habitats occupied by T. vulpecula
species richness of mistletoes was associated with the absence of fire and the presence of
reliable ground water supplies.
Trichosurus vulpecula were highly mobile with mean home ranges at Hale River of
44.21 � 22.76 ha and considerably higher than those recorded in previous studies in
Australia. Mean home ranges at Irving Creek were much smaller, at 4.99 � 1.46 ha and
VII
similar to that recorded in other studies in Australia. At both sites, males had larger home
ranges and there was a high degree of overlap with other males and females. At the Hale
River study site, T. vulpecula predominantly denned in caves or cavities in rocks, whereas at
Irving Creek all den sites were in large Eucalyptus camaldulensis on the drainage line. Adult
and pouch young sex ratios were at parity. During this study, T. vulpecula was found to
breed continuously, with births recorded in almost all months. Growth of the young were
more rapid than previously recorded for Trichosurus in Australia. This is interpreted as an
adaptation for living in an arid environment, enabling the young to achieve independence
before quality food supplies diminish.
No single exotic predator or competitor was solely responsible for the decline of T.
vulpecula in arid Australia, implying an interactive impact. Prey switching by dingoes from
rabbits to T. vulpecula, macropods and echidnas followed the crash of rabbit populations at
Hale River. Predation by dingoes on T. vulpecula was only recorded once, at the Irving
Creek study site, where numbers of rabbits remained stable throughout the study. The
impact of exotic herbivores occurred through habitat degradation rather than competition.
Evaluation of the ecological data collected during this study generally supports
current models of decline and extinction in medium-sized mammals in arid Australia,
integrating the effects of predators, competitors, drought and fire. However, the importance
of each factor on populations of T. vulpecula was found to vary depending on their location
in the landscape. This study suggests two separate models to explain the decline of T.
vulpecula in arid Australia after the arrival of Europeans. The first operates in the riparian
lowlands and the second on the rocky ranges. In both models, prior to European settlement,
T. vulpecula occupied refuge habitats characterised by readily available moisture for plant
growth (run on areas and/or shallow water tables) and soils with higher soil nutrient
concentrations. The impact of fires on these refugia was minimal, as Aboriginal burning
practices protected them with mosaic burning generally preventing large-scale fires from
developing. Following European settlement, the forces impacting on populations were
different in the riparian lowlands from those affecting rocky ranges.
In the riparian lowlands, the effects of rabbits and livestock together with predation
were found to have the major impact on T. vulpecula populations. Fire was not a significant
factor in these areas.
In the rocky ranges, fire was the most significant factor affecting T. vulpecula
populations. Introduced herbivores did not degrade these habitats as they did in the riparian
lowlands because the rugged and steep nature of the ranges acted as a physical barrier.
Similarly, predator numbers were lower because of the relative difficulty in moving over
rough ground and the generally lower relative abundance of preferred prey such as rabbits.
An adaptive management strategy needs to be implemented to determine the
effects of different management regimes on T. vulpecula population viability. The key
elements of a management strategy in the riparian lowlands involves the manipulation and
monitoring of predators, rabbits and livestock numbers. In the rocky ranges, the key
management strategy involves the implementation of a patch burning to prevent fires entering
habitats occupied by T. vulpecula. Importantly, any management strategies should involve
Aboriginal people. Trichosurus vulpecula is an important part of Aboriginal culture. Its
decline is of great concern to many people and several of the remaining populations and
potential reintroduction locations are on Aboriginal land. Because of their relationship with
the land and the animals, people have both the knowledge of the animal and the skills (such
as patch burning) to provide information to managers which will assist with management.
To achieve these management directions a coordinated national education programme
is required to inform and convince the Australian community that conservation of T. vulpecula
is deserving of attention in arid and semi-arid Australia. This is particularly important given
the perception that T. vulpecula is a common species throughout Australia, despite its massive
decline in arid Australia since European settlement.
38
Cheung, Him-chun Horace, and 張謙俊. "The impact of POSSUM score on long-term outcome of patients with colorectal cancer." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45160752.
39
Moro, Marcelo Freire. "Estrutura e bioinvasÃo de um fragmento de cerrado sobre os tabuleiros prÃ-litorÃneos na zona urbana de Fortaleza, CearÃ." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9320.
Анотація:
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorO crescimento urbano promove a destruiÃÃo e fragmentaÃÃo de ecossistemas, alÃm da introduÃÃo de grande nÃmero de espÃcies exÃticas. Parte destas espÃcies exÃticas tornamse invasoras e podem gerar impactos para a biodiversidade nativa. Fragmentos de vegetaÃÃo nas zonas urbanas sofrem invasÃes biolÃgicas, que se acumulam com o passar do tempo e modificam a estrutura e a composiÃÃo dos ecossistemas. Estudos sobre bioinvasÃo mostram que as bordas sÃo o habitat preferencial para a colonizaÃÃo por espÃcies adaptadas a distÃrbios. Assim, o objetivo deste trabalho foi verificar se as bordas de um fragmento de vegetaÃÃo localizado em uma matriz urbana sÃo mais susceptÃveis à bioinvasÃo do que o seu interior. Um fragmento de vegetaÃÃo savÃnica (cerrado) localizado sobre os tabuleiros prÃlitorÃneos na cidade de Fortaleza, CearÃ, foi selecionado para este estudo. Parcelas em transecto (Belt transect) foram estabelecidas no sentido borda-interior do fragmento de vegetaÃÃo, onde todos os indivÃduos lenhosos (exceto cipÃs) com PNS igual ou superior a 9cm foram inventariados. Coletas assistemÃticas das espÃcies tambÃm foram realizadas a fim de elaborar a lista florÃstica da Ãrea. Foram registradas 143 espÃcies vegetais no fragmento de cerrado, pertencentes a 58 famÃlias. Fabaceae foi a famÃlia de maior riqueza (27 espÃcies), seguida de Rubiaceae (oito espÃcies), Poaceae (oito espÃcies â trÃs exÃticas), Convolvulaceae (sete espÃcies), Malvaceae (seis espÃcies) e Myrtaceae (seis espÃcies â uma exÃtica). A densidade da comunidade foi de 1218 ind./ha e a Ãrea basal 7,34 m2/ha. A altura mÃdia das espÃcies amostradas foi 2,53 m  1,29 m (64% dos indivÃduos tem menos de 3 m) e o diÃmetro mÃdio foi 6,68 cm  5,67 cm (64% dos indivÃduos tem menos de 6 cm). A flora do fragmento de cerrado estudado consiste na associaÃÃo de espÃcies tÃpicas do cerrado do Brasil central com espÃcies comuns nos tabuleiros prÃ-litorÃneos, mas que nÃo ocorrem nos cerrados centrais. A densidade e a Ãrea basal da comunidade estudada foi baixa, mas dentro da amplitude registrada para o cerrado sensu stricto. Dos 1218 indivÃduos lenhosos amostrados, quais apenas quatro (pertencentes a duas espÃcies) sÃo exÃticos. A densidade e a frequÃncia de exÃticas lenhosas foi baixa (quatro indivÃduos em duas parcelas), de modo a nÃo permitir distinÃÃo quanto à intensidade da bioinvasÃo no ambiente de borda versus interior. Dada a singularidade da Ãrea estudada, que se constitui uma mancha de cerrado sobre os tabuleiros prÃ-litorÃneos na zona urbana de Fortaleza, CearÃ, recomenda-se que o fragmento de vegetaÃÃo seja convertido em uma UC municipal.
40
Machado, Adriana Marcondes. "Inventando uma intervenção na escola pública." Universidade de São Paulo, 1991. http://www.teses.usp.br/teses/disponiveis/47/47134/tde-03122013-150122/.
Анотація:
Este trabalho se inicia com uma cena que aconteceu durante uma intervenção realizada com um grupo de crianças, alunos de uma classe especial em uma Escola Estadual. O objetivo desta intervenção foi modificar as relações, muitas vezes cristalizadas, que essas crianças mantinham na classe especial. Após o relato desta experiência e de algumas versões das crianças em relação ao fato de serem consideradas alunos especiais, são feitas reflexões sobre a intervenção realizada. Utilizando um pensamento e uma prática acategóricos, a diferença é afirmada como positividade e tendência e não como anormalidade. Valorizou-se o funcionamento de diversas relações para buscar fortalecer tendências que um processo de cristalização das relações enfraquece.This paper begins with a scene that happened during an intervention with a group of students from a special education class in a State Public School. The objective of the intervention was to promote changes in the relationships, many of them criatalized, that the children had within the apecial class. After reporting this experience and the childrenoa versions regarding the fact that they are considered apecial studena, reflections were made concerning the intervention. Based on a non-cathegorical philosophy and practice, the difference ia affirmed as positivity and tendency, not as anormal ty. We aimed at enhancing other relationships that would conteract the process of cristalization.
41
Stewart, Hafiz. "Patterns of distribution and abundance of the Western Pygmy-Possum Cercartetus concinnus, in Ngarkat Conservation Park /." Adelaide, 1995. http://web4.library.adelaide.edu.au/theses/09SB/09sbs8488.pdf.
42
Roggelin, Matthias Johannes [Verfasser]. "Untersuchung und Adaption des POSSUM Score Systems für operative Eingriffe an der Niere / Matthias Johannes Roggelin." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2011. http://d-nb.info/1012216896/34.
43
Miller, John Douglas. "Buck-horned snakes and possum women: Non-white folkore, antebellum *Southern literature, and interracial cultural exchange." W&M ScholarWorks, 2010. https://scholarworks.wm.edu/etd/1539623556.
Анотація:
The antebellum American South was a site of continual human mobility and social fluidity. This cultivated a pattern of cultural exchange between black, indigenous, and white Southerners, especially in the Old Southwest, making the region a cultural borderland as well as a geographical one. This environment resulted in the creolization of many aspects of life in the region. to date, the literature of the Old South has yet to be studied in this context. This project traces the diffusion of African-American and Native American culture in white-authored Southern texts.;For instance, textual evidence in Old Southwestern Humor reveals a pattern of adaptations of folklore belonging to African-Americans. Johnson Jones Hooper's Some Adventures of Simon Suggs (1845) in particular reflects the presence of plots and motifs that originated in African trickster tales. Not all white Southern authors were menable to creolization, though. Novelists like William Gilmore Simms drew from but resisted the complete integration of non-white folklore in his historical romances. Native Americans and their culture frequently appear in his The Yemassee (1835), for instance, but always in a separate sphere.;The differences associated with the creolization of Old Southwestern Humor and the lack thereof in Southern historical romances reflect a distinction in Southern attitudes toward westward expansion and its social implications. In particular, the degree to which these authors did or did not resist creolization reflects their opinion about patterns of antebellum emigration and the backwoods social fluidity that contributed to the phenomenon of cultural exchange. Older conservatives like Simms, for instance, perceived the Old Southwest as a threat due to its rowdiness, materialism, and permeable social class. Novels by these authors displaced this milieu into the colonial past at an historical moment at which it became stabilized. The consequent elimination of Native Americans by whites in these texts marked a symbolic victory for order and stasis.;The texts of younger emigres to the South like Hooper reflect an alternate perspective. their embrace of the creative opportunities made possible by the social instability of the Old Southwest corresponds to their enthusiasm for the economic and social promise afforded by this recently settled region. In other words, the authors' openness to creolization mirrors a tolerance of the chaos born of mobility and a lack of structure. Suggs's antisocial exploits are adapted from African-American trickster tales whose characteristic disdain for authority and subversiveness contribute to Hooper's satire of traditional attitudes, including paternalism, which sought to limit this social flux.;These texts' competing viewpoints of the frontier allow scholars to get a sense of the diversity of social and political thought in the region---there was no monolithic Mind of the Old South. Additionally, acknowledging that these texts are a product of the multicultural environment reveals the contributions of Africans and Native Americans to Southern literature at its formative stage.
44
Silveira, Alexandre. "Redes neurais atratoras com padrões que possuem atividade em grafos aleatórios." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/164875.
Анотація:
Com o avanço das técnicas analíticas, tem sido possível estudadar redes neurais atratoras onde cada unidade de processamento é conectada com um número finito de vizinhos, sendo que esse número independe do tamanho do sistema. Aplicamos essas técnicas ao estudo de redes atratoras com padrões que possuem uma quebra de simetria sobre o número de bits ativos e quiscentes. O objetivo deste trabalho é estudar a capacidade da rede neural em armazenar padrões com atividade não nula, uma vez que a conectividade por neurônio é finita. Inicialmente, apresentamos os modelos predecessores de redes atratoras, como o modelo de Hopfield e os modelos de Amit, Gutfreund e Sompolinsky. Em tais modelos, o aprendizado é definido através de modificações sinápticas, inspiradas nas ideias de Hebb. Mostramos como é estimada a capacidade da rede. Mencionamos a introdução de uma função de energia para o sistema, que permite uma ligação com estudo de sistemas magnéticos através da mecânica estatística. Apresentamos também regras de aprendizado para lidar com padrões com atividade não nula. Num segundo momento, aplicamos o método de réplicas, utilizado para tratar sistemas desordenados, ao problema da rede atratora com conectividade e atividade dos padrões finitas. Utilizamos o formalismo de funções de ordem e fazemos uso do conceito de sub-redes, que permite particionar o grafo de acordo com os padrões a serem armazenados em cada neurônio. Obtemos, assim, uma função de ordem por sub-rede que contém toda informação sobre o estado do sistema. Aplicando o ansatz de simetria de réplicas, é possível derivar distribuições autoconsistentes dos campos locais para cada sub-rede. Tais distribuições passam a fornecer toda informação necessária para calcularmos os observáveis relevantes. As distribuições são calculadas numericamente a partir do método da dinâmica de populações. Em seguida, traçamos diagramas de fases para três regras de aprendizado. A partir desses, estimamos a capacidade, temperatura e atividade críticas. Observa-se a presença de fases de vidro de spin, transições decontínuas e pontos tricríticos.With the advance of analytical tools it has been possible to study attractor neural networks in which each processing unit is connected to a finite number of neighbours. Being that, the number of neighbours is independent of the size of the system. We apply these tools to the study of attractor networks in which the patterns have a broken symmetry with respect to the number of active and inactive bits. The objetive of this work is to study the capacity of the neural network to store patterns with activity different from zero, being that the conectivity per neuron is finite. First, we present the predecessor models of attractor networks like the Hopfield and Amit, Gutfreund e Sompolinsky ones. In such models the learning is defined through sinaptic modifications, inspired by Hebb’s ideas. We show how to estimate the storage capacity of the network. We mention the introduction of a energy function for the system, which allows a link with the study of magnetic systems through statistical machanics. We present learning rules to deal with patterns which have non zero activity. In the second part, we apply the replic method, utilized to deal with disordered systems to the problem of an attractor neural network with finite conectivity and activity. We utilized the formalism of order functions and the concept of sublattices, this concept allows to partition the graph according with the patterns to be stored in each neuron. This way, we obtain an order function per sublattice which contain all the information about the state of the system. Applying the replica symmetry ansatz it is possible to derive self-consistent distributions of the local fields per sublattice. Such distributions start to provide all the necessary information to calculate the relevant observables. These distributions are calculated numerically using the population dynamics method. Then, we draw phase diagrams for three learning rules. Using these, we estimate the storage capacity, the temperature and the critical activity. We observe the presence of spin glass phases, discontinuos phase transiotions and tricritical points.
45
Sasaki, Naoya. "Alpha-fetoprotein-producing pancreatic cancer cells possess cancer stem cell characteristics." Kyoto University, 2012. http://hdl.handle.net/2433/157414.
46
SHI, Hangyuan. "Will analysts learn from other analysts who possess superior private information." Digital Commons @ Lingnan University, 2016. https://commons.ln.edu.hk/fin_etd/15.
Анотація:
Based on a valuable testing venue in China where listed companies are required to disclose corporate site visit records of financial analyst to the public, this study examines whether analysts will learn from visiting analysts' forecasts that contain superior private information. I find that visiting forecasts tend to attract more analysts to issue forecasts in their aftermath than the prior forecasts issued by the same analysts but without conducting corporate site visit (non-visiting forecasts). The following effect is weaker when the visiting forecasts are more informative. In addition, other analysts’ forecasts following the visiting forecasts tend to move closer to the visiting forecasts than the forecasts following the non-visiting forecasts, with the effects being stronger for more informative visiting forecasts. Furthermore, followers experience a greater improvement in their forecast accuracy than the non-followers. This effect is also stronger when the visiting forecasts are more informative. Last but not the least, I find a decline in analyst forecast dispersion, an increase in common information, and an improvement in forecast accuracy in the period subsequent to the issuance of visiting analysts’ forecasts but no such effect for non-visiting forecasts. Collectively, the results suggest that analysts have incentive to learn from the forecasts that contain superior information and such learning activities tend to improve the information environment of the visiting firms.
47
Figueira, Fábio Gomes. "Involuções cujo conjunto de pontos fixos possui duas componentes." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306336.
Анотація:
Orientadores: Pedro Luiz Queiroz Pergher, Claudina Izepe RodriguesTese (doutorado) - Universidade Estadual de Campiinas, Instituto de Matematica, Estatistica e Computação Científica
Made available in DSpace on 2018-08-04T01:39:11Z (GMT). No. of bitstreams: 1 Figueira_FabioGomes_D.pdf: 601498 bytes, checksum: 0eb9b4953feb322f765ac36c21c7262a (MD5) Previous issue date: 2004
Doutorado
Matematica
Doutor em Matemática
48
com, aeveraardt@hotmail, and Annika Everaardt. "The impact of fire on the honey possum Tarsipes rostratus in the Fitzgerald River National Park, Western Australia." Murdoch University, 2003. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040611.105120.
Анотація:
The honey possum Tarsipes rostratus is a tiny (7 - 12 g) highly specialised flower-feeding marsupial endemic to the south-western corner of Australia. The impact of fire on this small mammal was studied, over a 19-year period, in the Fitzgerald River National Park, a large (330,000 ha) area of relatively undisturbed heathland/shrubland, rich in the proteaceous and myrtaceous plants upon which the honey possum appears to rely for food. The honey possum is the most abundant and widespread mammal in this Park.
Capture rates of honey possums were significantly related to the years since the vegetation was last burnt, annual rainfall in the preceding (but not the current) year, the season when trapping occurred, and the trapping grid operated. Capture rates declined markedly after fire and remained low (less than one third of those in long unburnt vegetation) for about 4 - 5 years following a fire. Rates of capture then increased steadily over the next 20 - 25 years, with maximal abundance recorded about 30 years after fire. Thereafter, there appeared to be a slight decline in capture rates, but even in the vegetation unburnt for longest (> 50 years since fire), honey possum abundance was substantial and relatively stable. In contrast to these changes in abundance, the structure of the honey possum population, with 79 % adults and 57 % males, appeared little influenced by fire history, annual rainfall, season or grid.
The increase in the rates of capture of honey possums following fire paralleled the pattern of availability of cover in the vertical and, to a lesser extent, horizontal plane. Indeed, projective foliage cover took around 20 years after fire to reach levels similar to those available in areas unburnt for even longer. The trend in capture rates was also congruent with the maturation of the most frequently visited foodplants of honey possums, particularly Banksia nutans (summer flowering) and B. baueri (winter flowering). Areas long unburnt still contained shelter and foodplants adequate for honey possums even 50 years or more after fire, with only slight evidence of senescence.
Pollen loads indicated that honey possums caught in burnt areas, where their preferred foodplants were absent, continued to feed on these favoured foodplants (Banksia and Dryandra spp.) at nearby unburnt areas. In addition, they also fed, in both burnt and long unburnt areas, upon a suite of other plant species that regenerated more rapidly from lignotubers and epicormic buds, as well as from seeds (e.g. Eucalyptus and Calothamnus spp.). Thus, honey possums appeared to persist with their preferences for feeding from a limited number of flowering plants despite some of these species not being available in recently burnt areas for many years. Nearby patches of unburnt vegetation can clearly be important refuges, feeding grounds and shelter for the few honey possums that visit recently burnt areas, and appear to be the source of honey possum colonists in the years following a fire.
Capture rates were also greater following years when rainfall was higher than average. Indeed, rainfall had as great an influence upon capture rates as time since fire. Capture rates were also consistently higher over winter, and to a lesser extent over summer, than in either autumn or spring. Individual grids, even those close together in apparently similar vegetation with a similar fire history, still differed significantly overall in their capture rates of honey possums. This last finding has implications for the use of chronosequences in the study of post-fire changes in biota.
Although not the primary focus of the study, data on the limited suite of other, far less abundant, small mammals present indicated that house mouse Mus musculus domesticus numbers peak soon after fire (about two years after fire), grey-bellied dunnart Sminthopsis griseoventer numbers somewhat later (about eight years after fire) and that southern bush rats Rattus fuscipes fiuscipes, like honey possums, are later successional species. Most species were present in vegetation over a range of post-fire ages, with data consistent with models based on sequential changes in relative abundance.
Like many Australian mammals, the range of the honey possum has contracted substantially over the last 200 years and the coastal heathlands of the south-west are its last stronghold. In terms of its conservation, this study indicates that, if possible, management burns in these heathlands should be separated by intervals of at least 20 years between successive burns, and preferably even longer. If burns are required more frequently to meet other management priorities, it is highly preferable that they are small and patchy, rather than large scale. Such practices may help ensure the long-term survival of this unique, highly specialised and endemic marsupial.
49
au, k. bryant@murdoch edu, and Kate Alexandra Bryant. "The mating system and reproduction in the honey possum, Tarsipes rostratus: a life-history and genetical perspective." Murdoch University, 2004. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20050505.140613.
Анотація:
The honey possum Tarsipes rostratus, a marsupial endemic to South-Western Australia, feeds exclusively upon nectar and pollen. It is one of the smallest marsupials, with adult females (8-12g) significantly larger than adult males (6-9g). Honey possum males have the longest sperm (356µm) recorded for any mammaland the testes represent 4.2% body weight, amongst the largest recorded formammal species. These features suggest that sperm competition is an importantpart of the mating system. This study used a combination of field based studies,DNA analysis and histological examination of the female reproductive tract toinvestigate the life history, multiple paternity and reproduction of the honey possum innatural populations in the Fitzgerald River National Park (FRNP), on the south coastof Western Australia.
This study drew upon earlier work on the honey possum in the FRNP in order to describe its life-history. The honey possum is short-lived (1-2 years), and attains sexual maturity whilst still growing. All four teats are occupied after birth, but the litter is reduced to 2 or 3 young during pouch life. The young have a relatively slow rate of
growth. Breeding occurs continuously throughout the year, but is affected by the flowering phenologies of its foodplants. The greatest proportion of females with
pouch-young occurs in winter; there are fewest pouch-young in autumn, a time of year when there is a dearth of flowers. Honey possums are essentially solitary animals, with no structured social unit, and male and female home ranges overlap. In captivity they are largely tolerant of one another, but larger females are behaviorally dominant to smaller females and to males.
The densities and structure of the honey possum populations in the FRNP were analyzed from trapping data collected over 19 years. Population densities fluctuated
significantly from season to season throughout the year, with changes in the flowering food resources available. There were also year-to-year differences in the intensity of those fluctuations, and these were significantly associated with rainfall in the previous year, and probably mediated through a lag effect in the flowering of the honey possums foodplants. The greatest densities of animals occurred over winter. In years following high rainfall, mean winter densities reached 88 individuals per
hectare. The lowest densities occurred in spring, and in years following low rainfall mean spring densities fell to 8 individuals per hectare. Even at these lowest densities, there is still the potential for interaction between males and females. A succession from high to low, then back to high densities was seen during the three years of the present study (2000-2002) and this shadowed a similar succession of changes in rainfall.
The proportion of females with pouch-young was significantly affected by the season, and by rainfall in the previous year. Years following low rainfall had a lower
proportion of females in a condition to breed. The autumn dip in breeding that occurred in all years was exacerbated following dry years. Of those females that did breed in 2001, a time of low resources, there was no difference in the size of the litter compared to 2000 and 2002, times of higher resource availability. The sex-ratio of pouch young was at parity, but there was a slight bias towards males among both juveniles (56%) and adults (58%). This was probably due to the greater movements shown by males. Sex ratios were not affected by changes in rainfall and density. Male-biased dispersal was detected using genetic data and the movement patterns of males showed that they moved greater distances than females during their normal
activity.
Analysis of four microsatellite loci revealed extremely high levels of variation, with 28 to 50 alleles per locus and a mean expected heterozygosity of 0.95. These are
amongst the highest seen in any microsatellite study of vertebrates. There was multiple paternity in 86% litters, using a minimum number of sires per litter method,
and in 95% litters, using an estimated number of sires method based upon the relatedness of litter males. This indicates that multiple mating is frequent in female
honey possums and is evidence for sperm competition. The estimated number of sires in a litter was often three or four. In 41% of cases, the number of sires was less
than the number of young in the litter, indicating that some males were more successful at siring offspring than others. Nevertheless, no more than two offspring in a litter were known to have been sired by the same male. Despite marked fluctuations in density from high in 2000, to low in 2001, then high again in 2002, the level of multiple paternity remained equally high in all years.
Embryonic diapause and female reproduction was investigated in the honey possum. All adult females examined, both with and without pouch-young, were either close to oestrus, had ovulated or were carrying conceptuses. The honey possum has a postpartum
oestrus and it was evident that this occurs approximately 2-4 days after birth. Cleavage and formation of the unilaminar blastocyst appears to occur rapidly over
approximately 5 days. Embryonic diapause proceeded in a two phase manner similar to other small possum species. The unilaminar blastocyst expanded rapidly at first; and then, from about 18-20 days after birth, the diameter of the blastocyst remained constant at approximately 1.2-1.8mm. No growth or development beyond the unilaminar stage was observed during pouch-life. The first signs of reactivation occurred during lactation, after pouch exit, and expansion of the blastocyst only occurred in one post-lactational female. The development of the corpus luteum
appeared different to patterns described for other marsupials, but its formation
coincided with the formation of the unilaminar blastocyst. The diameter of the corpus luteum remained constant throughout diapause. The histology of the reproductive
tract was generally similar to other marsupials. There were no sperm storage crypts in the female reproductive tract.
The length of pouch-life in the honey possum was 55-65 days, and the interval between litters of the same size varied between 65 and 100 days. Embryonic diapause may reduce the time between production of successive litters in the honey possum, but lifetime reproductive potential is reasonably low. Females had up to four litters over the period that they were captured. Thus, each litter represents a substantial proportion (25%) of a females lifetime reproductive output. Reproductive amortization occurred, with 61% loss overall, due to overproduction of ova, loss of conceptuses and reduction of the litter during lactation.
The behavioural dominance of females suggests that multiple mating is an active strategy, and this presumably allows the genetic quality of their offspring to be maximized. Males that succeed in sperm competition may be of better intrinsic quality. Overproduction of conceptuses by females presents the opportunity for them to select those fertilized by intrinsically viable males or genetically compatible males. Sexually active males are present all year round. Females were not synchronous in
their sexual receptivity, and this would lead to a skewed operational sex ratio, with more reproductive males than oestrous females. Since adult males are significantly
smaller than adult females and possess no ornaments or armaments, it is unlikely that males overtly fight for access to females. Rather, males appear to monitor the
reproductive status of females through smell, and probably compete in their ability to locate oestrous females. The risk and intensity of sperm competition is high, sexual
selection for a large investment in spermatogenesis is evident and competition after copulation is probably an important factor in the mating system. It is likely that males, as well as females mate multiply, and the mating system is promiscuous.
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Ramalho, Jaqueline Vilar. "Crianças em situação de abrigamento que possuem vínculos familiares: busca de significados." Universidade Católica de Pernambuco, 2008. http://www.unicap.br/tede//tde_busca/arquivo.php?codArquivo=310.
Анотація:
Esta pesquisa teve como objetivo geral: analisar os significados que crianças em situação de abrigamento que possuem vínculos familiares atribuem a esta situação e como objetivos específicos: conhecer o percurso trilhado por essas crianças até a situação de abrigamento; pesquisar como crianças em situação de abrigamento percebem o ambiente familiar estando excluídos temporariamente do mesmo e investigar o que significou o período de abrigamento na vida dessas crianças. A metodologia foi de natureza qualitativa. A coleta de dados se iniciou com as observações que nos subsidiaram no rapport com as crianças. Os instrumentos utilizados foram o Teste do Desenho da Família, as Fábulas de Düss e os prontuários ou pastas de encaminhamento existentes na instituição. No sentido de complementar os dados colhidos nos prontuários, entrevistamos profissionais da equipe da instituição de abrigamento. Seis crianças de ambos os sexos e com idade entre sete a nove anos participaram da pesquisa. Dentre os motivos de abrigamento obtivemos: abandono do lar pela mãe, negligência e gestação materna. No Teste do Desenho da Família todas apresentaram os seguintes aspectos: dificuldade para desenhar a própria família, agressividade observada através da eliminação de personagens, instabilidade e fragilidade nos desenhos (decerto, devemos considerar as circunstâncias de desenvolvimento das mesmas); cinco apresentaram dificuldades em se inserir no desenho; três não representaram os pais; duas acrescentaram outros familiares, sinalizando necessidade de afeto ou muita convivência com os mesmos, acréscimo de simbolismos; uma não representou a mãe e outra acrescentou pessoa da instituição. Nas Fábulas de Düss as respostas que apresentaram maior freqüência foram: duas crianças representaram agressividade e hostilidade diante da cena primária, assim como Complexo de Édipo vivido de forma angustiante, congruentes às histórias de vida de cada uma delas. Dessa forma, nossos dados apontaram um significado de família ambivalente e sem coesão, salientando fragilidade em sua dinâmica. Quanto ao abrigamento, em sua maioria (cinco), as crianças o relataram como tendo um significado positivo em suas vidas, afirmaram gostar de lá, embora isso não às levasse a rejeitar suas famíliasThe general objective of this research was: analyze the meanings given by children under shelter with family ties and as specific objectives: knowing the path taken by these children until they got under shelter through charts and interviews with the staff; research how the children under shelter realize the family environment being secluded temporarily from it and investigate the impact of sheltering in the lives of these children. The methodology was of a qualitative nature. The data collection began with information subsidized in rapport with the children. The instruments used were the Drawing the Family Test, Duss fables and charts or follow up folders existent in the institution. In order do complement the data obtained from the charts, we interviewed professionals from the staff of the sheltering institution. Six children, boys and girls between seven and nine years of age, participated in the research. Among the reasons for sheltering one can find: abandoning of the home by the mother, neglect and motherhood administration. In the Draw the Family Test, all presented the following aspects: difficulty in drawing their own family, aggression noticed by the elimination of characters, they reflected instability and fragility in the drawings (clearly, we must consider the circumstances of development of the children); five presented difficult of inserting themselves in the drawing; three did not represent the parents; two added other relatives, indicating the need of affection or too much dwelling with them, the adding of symbols; one did not represent the mother and another one added a member of the institution. In Dusss fables the most frequent answers, two children, the same that demonstrated aggression and hostility in face of the first scenery as well as the Complex of Edipo having the same storyline as their real lives. Therefore, the data pointed to a meaning of family ambivalence and no cohesion, highlighting the fragility in their dynamic. As to the sheltering, the majority (five) the children related that they had a positive meaning towards their lives, stated that they liked being in the institution, although this feeling didnt drive them to rejecting their families