Letteratura scientifica selezionata sul tema "Rare mamals"
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Articoli di riviste sul tema "Rare mamals"
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Harding, Lee E. "Rare mammals recorded in Borneo – Malaysia". Taprobanica 3, n. 2 (20 dicembre 2011): 107–9. http://dx.doi.org/10.47605/tapro.v3i2.56.
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Harding, Lee E. "Rare mammals recorded in Borneo – Malaysia". TAPROBANICA: The Journal of Asian Biodiversity 3, n. 2 (21 gennaio 2012): 107. http://dx.doi.org/10.4038/tapro.v3i2.3969.
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Ellis, Samuel, Daniel W. Franks, Stuart Nattrass, Michael A. Cant, Destiny L. Bradley, Deborah Giles, Kenneth C. Balcomb e Darren P. Croft. "Postreproductive lifespans are rare in mammals". Ecology and Evolution 8, n. 5 (31 gennaio 2018): 2482–94. http://dx.doi.org/10.1002/ece3.3856.
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Bykova, E. A., E. V. Vashetko, A. V. Esipov e M. A. Gritsyna. "RARE MAMMALS OF KASKADARYA PROVINCE OF UZBEKISTAN". Tambov University Reports. Series: Natural and Technical Sciences 22, n. 5-1 (2017): 846–49. http://dx.doi.org/10.20310/1810-0198-2017-22-5-846-849.
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Fancourt, Bronwyn A. "Making a killing: photographic evidence of predation of a Tasmanian pademelon (Thylogale billardierii) by a feral cat (Felis catus)". Australian Mammalogy 37, n. 1 (2015): 120. http://dx.doi.org/10.1071/am14044.
Testo completoAbstract (sommario):
Feral cats (Felis catus) have contributed to the extinction of numerous Australian mammals and are a major threat to many species of conservation significance. Small mammals are considered to be those at greatest risk of cat predation, with risk typically inferred from dietary studies. However, dietary studies may provide only weak inference as to the risk of cat predation for some species. The most compelling evidence of predation risk comes from direct observation of killing events; however, such observations are rare and photographic evidence is even rarer. I present photographic evidence of a feral cat killing and consuming an adult female Tasmanian pademelon (Thylogale billardierii). This observation provides direct evidence that feral cats can kill prey up to 4 kg in body mass, with potential implications for the conservation of medium-sized mammals.
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Starkov, A. I., e I. V. Moroldoev. "RARE MAMMALS IN THE NORTHERN SELENGA MID-MOUNTAINS". Proceedings of the Tigirek State Natural Reserve, n. 3 (2010): 276–80. http://dx.doi.org/10.53005/20767390_2010_3_276.
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Brain, Paul F. "Aggression in female mammals: Is it really rare?" Behavioral and Brain Sciences 22, n. 2 (aprile 1999): 218. http://dx.doi.org/10.1017/s0140525x9926181x.
Testo completoAbstract (sommario):
The view that female mammals are more docile appears to arise in part from imposing human values on animal studies. Many reports of sexual dimorphism in physical aggression favouring the male in laboratory rodents appear to select circumstances where that expectation is supported. Other situations that favour the expression of conflict in females have been (until recently) relatively little studied. Although female rodents generally do not show the “ritualised” forms of conflict that characterise male sexual competition, they can use notably damaging strategies (especially if they are of short duration). Such considerations might weigh in the selection of strategies by our own species.
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Heidt, Gary A., e Stephen R. Humphrey. "Rare and Endangered Biota of Florida. Volume I. Mammals". Journal of Wildlife Management 57, n. 4 (ottobre 1993): 937. http://dx.doi.org/10.2307/3809103.
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Harkins, Kristina M., Doug Keinath e Merav Ben-David. "It’s a trap: Optimizing detection of rare small mammals". PLOS ONE 14, n. 3 (5 marzo 2019): e0213201. http://dx.doi.org/10.1371/journal.pone.0213201.
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Scotts, DJ, e SA Craig. "Improved Hair-Sampling Tube for the Detection of Rare Mammals". Wildlife Research 15, n. 4 (1988): 469. http://dx.doi.org/10.1071/wr9880469.
Testo completoAbstract (sommario):
A modified hair-sampling tube constructed from readily available PVC fittings is described. The use of aluminium screens to protect the bait source means that the hair-sampling tube remains attractive for extended periods. The hair-sampling tube has proven useful as a survey tool in the detection of iess common mammal species.
Tesi sul tema "Rare mamals"
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Potts, Joanne M. "Estimating abundance of rare, small mammals : a case study of the Key Largo woodrat (Neotoma floridana smalli)". Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2068.
Testo completoAbstract (sommario):
Estimates of animal abundance or density are fundamental quantities in ecology and conservation, but for many species such as rare, small mammals, obtaining robust estimates is problematic. In this thesis, I combine elements of two standard abundance estimation methods, capture-recapture and distance sampling, to develop a method called trapping point transects (TPT). In TPT, a "detection function", g(r) (i.e. the probability of capturing an animal, given it is r m from a trap when the trap is set) is estimated using a subset of animals whose locations are known prior to traps being set. Generalised linear models are used to estimate the detection function, and the model can be extended to include random effects to allow for heterogeneity in capture probabilities. Standard point transect methods are modified to estimate abundance. Two abundance estimators are available. The first estimator is based on the reciprocal of the expected probability of detecting an animal, ^P, where the expectation is over r; whereas the second estimator is the expectation of the reciprocal of ^P. Performance of the TPT method under various sampling efforts and underlying true detection probabilities of individuals in the population was investigated in a simulation study. When underlying probability of detection was high (g(0) = 0:88) and between-individual variation was small, survey effort could be surprisingly low (c. 510 trap nights) to yield low bias (c. 4%) in the two estimators; but under certain situations, the second estimator can be extremely biased. Uncertainty and relative bias in population estimates increased with decreasing detectability and increasing between-individual variation. Abundance of the Key Largo woodrat (Neotoma floridana smalli), an endangered rodent with a restricted geographic range, was estimated using TPT. The TPT method compared well to other viable methods (capture-recapture and spatially-explicit capture-recapture), in terms of both field practicality and cost. The TPT method may generally be useful in estimating animal abundance in trapping studies and variants of the TPT method are presented.
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Jůnek, Tomáš. "Camera trap as a non-invasive tool in research on rare and elusive mammals". Doctoral thesis, Česká zemědělská univerzita v Praze, 2016. http://www.nusl.cz/ntk/nusl-259693.
Testo completoAbstract (sommario):
Knowledge of the richness of species that inhabit a particular area is an essential metric for both conservationists and practitioners. Relatively cost-efficient and easily standardized solution has occurred in last the decades with the massive digitalization of photography, the camera trap. Such an independent detector is bias-free in the probability of recording objects passing by and in most cases does not disturb animals. Recent discoveries of new mammal species are proof of this. Moreover, camera traps allow for insight into the otherwise hidden behaviour of even the most timid animals. My interest in photography, endangered animal species and nature conservation has led me to the decision to apply a novel method in practice. Me and my team have focused on three different use-confirmation of the accuracy of capture-recapture population estimates, temporal overlaps of invasive species with its prey and competitors, and first ever camera-trapping species inventory in the Niokolo-Koba National Park. Thanks to personal experiences and contacts from World biodiversity hotspots I was able to successfully employ an approach and carry out field studies. I hope that our results will contribute to the development of effective conservation strategies and the methodology itself.
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Keith, Mark. "Conservation assessment of South African mammals". Thesis, Connect to this title online, 2005. http://upetd.up.ac.za/thesis/available/etd-02142006-162024/.
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Schwarz, Lisa Kimberley. "Survival rate estimates of Florida manatees (Trichechus manatus latirostris) using carcass recovery data". Diss., Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/schwarz/SchwarzL1207.pdf.
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Watanabe, Brett Kaoru. "Differences in Basal Metabolic Rates, Heart Masses, and Hematocrits of Bats, Terrestrial Mammals, and Birds". Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/cmc_theses/836.
Testo completoAbstract (sommario):
Bats are the only mammals capable of powered flight. In flight, bats consume up to 20 times more oxygen per hour than under basal conditions. This is twice the increase reported for running mammals of the same body sizes. Birds are the only other group of vertebrate capable of powered flight. By plotting morphological and physiological parameters against body mass for bats, terrestrial mammals, and birds, we can observe to what extent these parameters permit high rates of oxygen delivery necessary for flight.
In this study we analyzed basal metabolic rate, heart mass, and hematocrit, and compared how differently they scale in the afore-mentioned groups. We found that larger heart masses are associated with the ability to fly; hematocrit values for birds change markedly with body size, while those for mammals and bats are nearly independent of body size; and that BMR scales differently in all three groups.
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Matvienko, V. "Ecology and distribution of rare mammal species in the south regions of Ukraine (on the example of the wolf)". Thesis, Видавництво СумДУ, 2012. http://essuir.sumdu.edu.ua/handle/123456789/26648.
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Palazy, Lucille. "La chasse aux trophées : menace ou alliée pour les espèces rares". Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10020/document.
Testo completoAbstract (sommario):
La chasse aux trophées, type de chasse récréative dont l'objectif premier est de prélever un trophée d'intérêt, est un sujet très controversé. Cette activité est potentiellement génératrice d'un effet Allee anthropogénique (EAA). Ce processus démographique stipule que la valorisation de la rareté d'une espèce peut stimuler son exploitation et mener à son extinction. L'objectif de ce travail a été de tester le risque d'EAA dans la chasse aux trophées. Nous avons mis en évidence que les espèces rares ont une forte valeur économique dans la chasse aux trophées, quelque soit la taille du trophée, ce qui témoigne d'une demande forte pour ces espèces. Nous avons également montré que le nombre d'importations/exportations de trophées et le nombre de trophées de chasse enregistrés par le Safari Club International s'accroît pour les espèces les plus rares lorsque l'indice de rareté de l'espèce augmente. La chasse aux trophées sur les espèces rares a été proposée comme outil pour financer leur conservation. Cependant, nos résultats valident le risque d'EAA pour ces espèces. De plus, les chasseurs ne semblent pas motivés en priorité par la participation à la conservation de la vie sauvage et le peu de données disponibles sur les populations, la chasse illégale, la corruption et le manque de contrôle rendent possible l'exploitation non durable de ces ressources à forte valeur économique. Néanmoins, la vie sauvage doit apporter des bénéfices économiques pour motiver sa préservation. Ainsi, la chasse aux trophées des espèces rares peut être utilisée pour financer leur conservation mais certaines mesures sont à prendre au préalable pour prévenir leur surexploitationTrophy hunting, which is a form of recreational hunting with the main objective of collecting a trophy of interest, is a controversial subject. This activity could potentially generate an anthropogenic Allee effect (AAE). This demographic process states that the valuation of rarity could drive rare species exploitation and even lead to their extinction. Our project aims at testing the potential for an AEE in trophy hunting. We demonstrate that rare species have a high financial value, regardless of the trophy size, indicating that there is a high demand for those species. We also show that the number of trophies traded internationally and the number of recorded trophies by the Safari Club International (one of the largest clubs for international trophy hunters in the USA) rises as the degree of rarity (as measured by a rarity index) increases. Trophy hunting of rare species has been proposed as a tool to fund their conservation. However, our results indicate that there is a risk of an AAE for rare species. Furthermore, the combined effects of trophy hunting, illegal hunting, corruption as well as the lack of population knowledge and of management controls have potential to result in the unsustainable exploitation of rare species of high financial value. Nonetheless, trophy hunting has potential to generate strong financial incentives that are necessary for wildlife preservation. Such incentives are only likely to be effective if strict measures are required and enforced to prevent overexploitation of rare trophy species
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Lengyel, Megan S. "Reproduction, Energy Budget, and the Sibling Effect in Nine-Banned Armadillo, Dasypus Novemcinctus". University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1304698954.
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Walker, Kevin R. "Climatic Dependence of Terrestrial Species Assemblage Structure". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23697.
Testo completoAbstract (sommario):
An important goal of ecological studies is to identify and explain patterns or variation in species assemblages. Ecologists have discovered that global variation in the number of species in an assemblage relates strongly to climate, area, and topographic variability in terrestrial environments. Is the same true for other characteristics of species assemblages?
The focus of this thesis is to determine whether species assemblage structure, defined primarily as the body mass frequency distributions and species abundance distributions relate in convergent ways to a set of a few environmental variables across broad spatial scales.
First, I found that for mammals and trees most of their geographic variation across North and South America in assemblage structure is statistically related to temperature, precipitation, and habitat heterogeneity (e.g. different vegetation types) in convergent ways.
I then examined bird assemblages across islands and continents. Despite the evolutionary and ecological differences between island and continental assemblages, I found that much of the variation in bird assemblage structure depends on temperature, precipitation, land area, and island isolation in congruent patterns in continent and island bird assemblages.
Frank Preston modeled species richness based on the total number of individuals and the number of individuals of the rarest species. Building on Preston’s model, Chapter 2 hypothesized that gradients of diversity correlate with gradients in the number of individuals of the rarest species, which in turn are driven by gradients in temperature and precipitation. This hypothesis assumes that species abundance distributions relate to temperature and precipitation in similar ways anywhere in the world. I found that both the number of individuals of the rarest species (m) and the proportion of species represented by a single individual in samples of species assemblages (Φ) were strongly related to climate. Moreover, global variation in species richness was more strongly related to these measures of rarity than to climate. I propose that variation in the shape of the log-normal species abundance distribution is responsible for global gradients of species richness: rare species (reflected in m and Φ) persist better in benign climates.
Even though body mass frequency distributions of assemblages show convergent patterns in relation to a set of a few environmental variables, the question remains as to what processes are responsible for creating the geographical variation in the body-size distribution of species. Several mechanisms (e.g. heat conservation and resource availability hypotheses) have been proposed to explain this variation. Chapter 5 tested and found no empirical support for the predictions derived from each of these mechanisms; I showed that species of all sizes occur across the entire temperature gradient.
In conclusion, assemblage structure among various taxonomic groups across broad spatial scales relate in similar ways to a set of a few environmental variables, primarily mean annual temperature and mean annual precipitation. While the exact mechanisms are still unknown, I hypothesize several to explain the patterns of convergent assembly.
Résumé
Un but important de l'écologie est d'identifier et d'expliquer la variation de premier ordre dans les caractéristiques des assemblages d'espèces. Un des patrons ayant déjà été identifié par les écologistes, c'est que la variation mondiale de la richesse en espèces est liée à la variation du climat, de l'aire et de la topographie. Est-ce que d'autres caractéristiques des assemblages d'espèces peuvent être reliées à ces mêmes variables?
Le but de cette thèse est de déterminer si la structure des assemblages d'espèces, ici définie comme la distribution des fréquences de masse corporelle ainsi que la distribution d'abondances des espèces, est reliée de manière convergente à un petit ensemble de variables environnementales, et ce, partout dans le monde.
D'abord, j'ai déterminé que, pour les mammifères et les arbres, la majorité de la variation géographique dans la structure des assemblages d'espèces est reliée statistiquement à température, précipitation, et l’hétérogénéité du couvert végétal , et ce, de manière convergente pour l'Amérique du Nord et du Sud.
Je me suis ensuite penché sur l'assemblage des oiseaux sur les îles et les continents. Malgré les larges différences évolutives et écologiques qui distinguent les îles des continents, je démontre que la majorité de la variation dans la structure des assemblages d'oiseaux dépend de la température, la précipitation, la superficie et l’isolation de façon congruente sur les îles et les continents.
Frank Preston a modélisé la richesse en espèces d'une localité, basée sur le nombre total d'individus ainsi que le nombre d'individus de l’espèce la plus rare. En s'appuyant sur les modèles de Preston, Chapître 3 propose une nouvelle hypothèse voulant que les gradients de diversité dépendent des gradients du nombre d'individus de l’espèce la plus rare. Celle-ci dépend des gradients de température et de précipitation. Cette hypothèse repose sur le postulat que la distribution d’abondances des espèces dépend de la température et la précipitation, et ce, de la même manière n’importe où au monde. J’ai mis en évidence que le nombre d’individus de l’espèce la plus rare (m), ainsi que la proportion d’espèces représentées par un individu unique () dans des échantillons locaux étaient fortement reliés au climat. D’ailleurs, la variation globale de la richesse en espèces était plus fortement reliée à ces indices de rareté qu’au climat. Je propose que la variation dans la forme de la distribution log-normale d’abondances d’individus soit responsable des gradients mondiaux de richesse en espèces. En d’autres mots, les espèces rares (indiquées par m et ) persistent mieux dans des climats bénins.
Malgré que la distribution des fréquences de masse corporelle des assemblages d'espèces soit liée de manière convergente à seulement quelques variables environnementales, la question demeure à savoir quels processus sont responsables des gradients géographiques de variation en masse corporelle des espèces. Plusieurs mécanismes ont été proposés pour expliquer cette variation. Dans Chapitre 5, j'ai testé les prédictions dérivées de chacun de ces mécanismes sans trouver de support empirique pour aucun. Je démontre aussi que des espèces de toutes tailles se retrouvent sur le gradient de température en entier.
En conclusion, la structure des assemblages d'espèces, pour différents groupes taxonomiques et à travers le monde, est liée de façon similaire à un petit nombre de variables environnementales. Bien que les mécanismes soient encore inconnus, j'en propose plusieurs pouvant expliquer ces patrons d'assemblages convergents.
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Dyer, Siobhan Margaret. "Population size, demography and spatial ecology of cheetahs in the Timbavati Private Nature Reserve, South Africa". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1002058.
Testo completoAbstract (sommario):
The cheetah (Acinonyx jubatus) has experienced a drastic decline in numbers over the last 20 years globally and is currently listed as vulnerable by the International Union for the Conservation of Nature (IUCN). In South Africa, there are only an estimated 763 free-ranging cheetahs and conflict with humans is arguably the most significant reason for this low number. The aim of my study was to determine the population size and demographic characteristics of the cheetah population within the Timbavati Private Nature Reserve (TPNR), South Africa, and to contribute to a better understanding of cheetah space use and habitat selection. The research was conducted on TPNR between November 2009 and June 2011 and I used a photographic survey to assess cheetah population size and demographic characteristics. Location data was obtained by collaring two adult male cheetahs with GPS/GSM collars and ad hoc sightings data from across the reserve for an adult female with cubs and three adolescent females. A relatively high minimum population density of 4.46 cheetahs/100km² was estimated, signifying a relatively healthy cheetah population. The sex ratio data indicated a higher male to female ratio and an average litter size of three cubs. The relatively high cub survival rate and density is promising in terms of the status of species within the area, as the data denote the success and potential persistence of the species. Cheetah home ranges varied between 20.97km² for the female with cubs and 659.65km² for the younger collared male. Season did not appear to be a determining factor in terms of home range sizes for the three social groups within the TPNR. However, the males did show a slight increase in their home range sizes during the dry season when resources where presumably more widespread. My results indicate that the cheetah is an adaptable species, flexible in behaviour and able to tolerate a variety of habitat types. Such knowledge is fundamental for planning and implementing the effective management and conservation of cheetahs in South Africa.
Libri sul tema "Rare mamals"
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institutas, Vilniaus Universitetas Ekologijos, a cura di. The common dormouse, Muscardinus avellanarius: Ecology, population structure and dynamics. Vilnius: Vilniaus universiteto Ekologijos institutas, 2008.
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Centre, World Conservation Monitoring, a cura di. Endangered mammals! Milwaukee: Gareth Stevens, 1996.
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Jayson, E. A. Rare and endangered mammals of Kerala. Peechi, India: Division of Wildlife Biology, Kerala Forest Research Institute, 1996.
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P, Inskipp T., Barzdo Jon e Nature ConservancyCouncil, a cura di. World checklist of threatened mammals. (Peterborough): Nature Conservancy Council, 1987.
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Central Tibetan Administration-in-Exile (India). Environment & Development Desk., a cura di. The endangered mammals of Tibet. Dharamsala: Environment and Development Desk, Dept. of Information and International Relations, Central Tibetan Administration, 2005.
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Oliver, William L. R. Threatened endemic mammals of the Atlantic forest region of south-east Brazil. Jersey, Channel Islands: Jersey Wildlife Preservation Trust, 1991.
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G, Burton Vivien, e Pearson Bruce, a cura di. The Collins guide to the rare mammals of the world. Lexington, Mass: S. Greene Press, 1988.
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H, Khan M. Monirul, Ahmed Rashiduzzaman, Joarder Nargis Banu, Islam Md Anwarul, Ameen Mahmud-ul, Nishat Ainun, International Union for Conservation of Nature and Natural Resources. e International Union for Conservation of Nature and Natural Resources. Bangladesh Country Office., a cura di. Red book of threatened mammals of Bangladesh. Dhaka: IUCN Bangladesh, 2000.
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Temple, Helen J. The status and distribution of European mammals. Gland, Switzerland: IUCN the World Conservation Union, 2007.
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Bille, Matthew A. Rumors of existence: Newly discovered, supposedly extinct, and unconfirmed inhabitants of the animal kingdom. Blaine, WA: Hancock House, 1995.
Cerca il testo completoCapitoli di libri sul tema "Rare mamals"
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Sterenczak, Katharina Anna, Ingo Nolte e Hugo Murua Escobar. "RAGE Splicing Variants in Mammals". In Methods in Molecular Biology, 265–76. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-62703-230-8_16.
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Weir, Caroline R. "Rare and Vagrant Cetacean Species in Europe". In Handbook of the Mammals of Europe, 1–39. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-319-65038-8_113-1.
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Naszlady, A., e L. Kiss. "Resonance Principle and the Heart Rate of Mammals". In IFMBE Proceedings, 540–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23508-5_140.
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Snow, Michael H. L. "Control of Embryonic Growth Rate and Fetal Size in Mammals". In Human Growth, 67–82. Boston, MA: Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-2101-9_4.
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Akamatsu, Tomonari, Yoshimi Hatakeyama, Takahito Kojima e Hideo Soeda. "The Rate with which a Harbor Porpoise Uses Echolocation at Night". In Marine Mammal Sensory Systems, 299–315. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3406-8_22.
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Eisermann, K., e W. Stöhr. "Diurnal Heart Rate Rhythms in Small Mammals: Species-Specific Patterns and Their Environmental Modulation". In Temporal Variations of the Cardiovascular System, 87–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-662-02748-6_3.
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"Rare Cetaceans". In Britain's Sea Mammals, 106–16. Princeton University Press, 2014. http://dx.doi.org/10.1515/9781400844968.106.
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"RARE AND ENDANGERED SPECIES". In California Mammals, 17–22. University of California Press, 2023. http://dx.doi.org/10.2307/jj.8500898.5.
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"RARE AND ENDANGERED SPECIES". In California Mammals, 17–22. University of California Press, 1988. http://dx.doi.org/10.1525/9780520315402-004.
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Searle, J. B. "Miniature mammals: life-history strategies and macroevolution". In Miniature Vertebrates The Implications of Small Body Size, 159–74. Oxford University PressOxford, 1996. http://dx.doi.org/10.1093/oso/9780198577874.003.0009.
Testo completoAbstract (sommario):
Abstract Most mammal species are smaller than 60 g. The smallest species are mainly shrews, myomorph rodents, and insectivorous bats. A bias in data availability has led most previous work on patterns of mammal life-history evolution to focus on unusually large species. We review the major findings of such comparative studies, beginning with allometries of key variables and moving on to patterns of correlations among residuals. Every date, weight, and rate scales tightly with adult size across mammal species: small mammals tend to live faster and die younger than large species. This fast-slow continuum is also apparent when body size is factored out. We discuss two very different optimality models, one aiming to understand the driving forces behind life-history variation, the other trying to explain the macroevolutionary pattern of body size among species. Our comparative analysis finds that, among small mammals, most of the variation in life histories is independent of body size, but that correlations among residuals are broadly similar to those in mammals as a whole: the slow-fast continuum is still present. The size independence of the variation shows that quite radical life-history changes are possible without any change in body size being necessary: mammals are not tightly constrained by allometry. Interestingly, mammals that are smaller than their relatives have relatively small litters of large offspring. Our findings lend at best qualified support to the models we discuss.
Atti di convegni sul tema "Rare mamals"
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Guzas, Emily L., Stephen E. Turner, Matthew Babina, Brandon Casper, Thomas N. Fetherston e Joseph M. Ambrico. "Validation of a Surrogate Model for Marine Mammal Lung Dynamics Under Underwater Explosive Impulse". In ASME 2019 Verification and Validation Symposium. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/vvs2019-5143.
Testo completoAbstract (sommario):
Abstract Primary blast injury (PBI), which relates gross blast-related trauma or traces of injury in air-filled tissues or those tissues adjacent to air-filled regions (rupture/lesions, contusions, hemorrhaging), has been documented in a number of marine mammal species after blast exposure [1, 2, 3]. However, very little is known about marine mammal susceptibility to PBI except in rare cases of opportunistic studies. As a result, traditional techniques rely on analyses using small-scale terrestrial mammals as surrogates for large-scale marine mammals. For an In-house Laboratory Independent Research (ILIR) project sponsored by the Office of Naval Research (ONR), researchers at the Naval Undersea Warfare Center, Division Newport (NUWCDIVNPT), have undertaken a broad 3-year effort to integrate computational fluid-structure interaction techniques with marine mammal anatomical structure. The intent is to numerically simulate the dynamic response of a marine mammal thoracic cavity and air-filled lungs to shock loading, to enhance understanding of marine mammal lungs to shock loading in the underwater environment. In the absence of appropriate test data from live marine mammals, a crucial part of this work involves code validation to test data for a suitable surrogate test problem. This research employs a surrogate of an air-filled spherical membrane structure subjected to shock loading as a first order approximation to understanding marine mammal lung response to underwater explosions (UNDEX). This approach incrementally improves upon the currently used one-dimensional spherical air bubble approximation to marine mammal lung response by providing an encapsulating boundary for the air. The encapsulating structure is membranous, with minimal simplified representation not accounting for marine mammal species-specific and individual animal differences in tissue composition, rib mechanics, and mechanical properties of interior lung tissue. NUWCDIVNPT partnered with the Naval Submarine Medical Research Laboratory (NSMRL) to design and execute a set of experiments to investigate the shock response of an air-filled rubber dodgeball in a shallow underwater environment. These tests took place in the 2.13 m (7-ft) diameter pressure tank at the University of Rhode Island, with test measurements including pressure data and digital image correlation (DIC) data captured with high-speed cameras in a stereo setup. The authors developed 3-dimensional computational models of the dodgeball experiments using Dynamic System Mechanics Advanced Simulation (DYSMAS), a Navy fluid-structure interaction code. DYSMAS models of a variety of different problems involving submerged pressure vessel structures responding to hydrostatic and/or UNDEX loading have been validated against test data [4]. Proper validation of fluid structure interaction simulations is quite challenging, requiring measurements in both the fluid and structure domains. This paper details the development of metrics for comparison between test measurements and simulation results, with a discussion of potential sources of uncertainty.
2
Sousa, André Maroccolo de, Ana Luíza Fleury Luciano, Sayra Rayane Tioto Labre, Anita Celia Naves da Silva, Miguel Pereira de Queiroz Júnior e Juarez Antônio de Sousa. "Mastite crônica granulomatosa: um relato de caso". In 45º Congresso da SGORJ XXIV Trocando Ideias. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/jbg-0368-1416-20211311052.
Testo completoAbstract (sommario):
Introdução: A mastite granulomatosa (MG) é uma doença inflamatória benigna e crônica da mama, sendo mais prevalente em mulheres na menacme. A etiologia da MG é desconhecida e ela é caracterizada por uma reação granulomatosa crônica composta de células epitelioides, células gigantes multinucleadas dos tipos corpo estranho e de Langhans. A doença manifesta-se clinicamente com fístulas, úlceras e mastalgia. Na mamografia, pode-se encontrar distorção arquitetural, assimetria focal e nódulos irregulares, e a ultrassonografia de mamas evidencia abcesso. O tratamento primário da MG - a biópsia excisional e, em casos de lesões extensas, a cirurgia - faz-se necessário, buscando sempre bons resultados estéticos. Relato do caso: Paciente F.L.R.C., 55 anos, apresentou tumor em mama esquerda, e foi realizada ressecção segmentar no ano 2019. O exame histopatológico revelou tratar-se de mastite granulomatosa. A paciente realizou tratamento adjuvante com antibióticos e prednisolona 40 mg/dia, porém retornou no ano de 2021 com quadro de tumor com consistência amolecida, ocupando a região de quadrante superior medial (QSM) da mama esquerda. Foi feita a ressecção cirúrgica completa da lesão, englobando toda a pele do QSM mama esquerda. Realizou-se retalho local para reconstrução mamaria, enxerto de aréola e mamilo esquerdo, associado a corticoide (prednisolona 40 mg/dia) com dosagens regressivas semanais. Conclusão: A mastite granulomatosa é uma doença rara da mama, crônica, sendo o diagnóstico histopatológico indispensável, visto que a clínica e os exames de imagem podem simular neoplasia maligna e abcesso, e as punções por agulha são inconclusivas. No caso da paciente em questão, a literatura sugere ressecção ampla das lesões, com margens livres. A terapia antimicrobiana é recomendada nesses casos em razão da alta probabilidade de infecção. Até o momento, não há protocolos de condutas específicas para uso de corticoides, contudo o tratamento preferencial é feito com prednisolona 40 mg/dia.
3
Altukhov, Alexey, R. Andrews, T. Gelatt e Vladimir Burkanov. "Does Steller sea lion (Eumetopias jubatus) pup weight explain differences in first-year survival rate in populations with different abundance trends?" In Marine mammals of the Holarctic. RPO “Marine Mammal Council”, 2020. http://dx.doi.org/10.35267/978-5-9904294-7-5-2020-1-33-41.
Testo completo
4
Carneiro Filho, Genilson Gomes, Flávia Maria de Souza Climaco, Afranio Coelho-Oliveira, Bianca Kurtz Fontoura, Maria Celia Resende Djahjah e Ana Helena Correia Carneiro. "Carcinoma primário em mama acessória axilar: relato de caso". In 44° Congresso da SGORJ - XXIII Trocando Ideias. Zeppelini Editorial e Comunicação, 2020. http://dx.doi.org/10.5327/jbg-0368-1416-2020130231.
Testo completoAbstract (sommario):
Introdução: A incidência de polimastia na população varia de 0,4 a 6,0%. O tecido glandular ectópico pode ser acometido por patologias benignas ou malignas. Entretanto, o carcinoma das mamas acessórias é raro, representando cerca de 0,3 a 0,6% de todos os cânceres de mama. Objetivo: Relatar um caso de carcinoma em mama acessória axilar, discutindo as características clínico-patológicas, as dificuldades do diagnóstico e as controvérsias em relação ao tratamento, em razão de sua raridade. Relato de Caso: Paciente de 61 anos, branca, apresenta queixa de nódulo em região axilar há um mês, com dor à palpação. Refere hipertensão arterial e hipotireoidismo. Menarca aos 12 anos. IIIG IIP IA. Amamentou por dez meses. Menopausa aos 52 anos. Nega reposição hormonal. Nega história familiar de neoplasias. Ao exame, apresenta mamas simétricas, flácidas e indolores. Ausência de retrações, abaulamentos ou nodulações. Presença de tecido glandular ectópico em região axilar direita, com nódulo de consistência endurecida, não aderido a planos profundos, medindo 2,0×3,0 cm, com lesão ulcerada não exsudativa. A mamografia demonstrou padrão de lipossubstituição, sem sinal de doença. BI-RADS I. A ultrassonografia detectou lesão nodular de alta densidade com limites imprecisos, espiculada, em mama acessória na região axilar direita. Mamas tópicas sem alterações. BI-RADS V. Realizada core biópsia com laudo de adenocarcinoma pouco diferenciado com padrão de crescimento difuso ou em fileiras, podendo corresponder a carcinoma lobular infiltrante ou a ductal infiltante ou ductal infiltrante com características lobulares. Imuno-histoquímica: CK7 positivo, CK20 negativo, antígeno carcinoembriônico positivo, RE positivo (90%), RP positivo (80%), KI67 positivo (50%), TTF-1 negativo, CERB B-2 negativo, E-CADERINA negativa. Indicada ressecção de mama acessória axilar e biópsia de linfonodo sentinela, sendo realizada injeção peritumoral de azul patente. O laudo histopatológico demonstrou carcinoma ductal infiltrante pouco diferenciado grau 3, com características lobulares, margens livres de neoplasia. Presença de metástase em um de dois linfonodos examinados. Realizada radioterapia adjuvante, quimioterapia e uso de anastrozol. Paciente permanece em acompanhamento, sem evidência de doença. Discussão: O carcinoma em mama acessória é raro e em 80% dos casos localiza-se na região axilar. O tipo histológico mais frequente é o carcinoma invasivo do tipo não especial (72%), seguido do lobular infiltrante. O diagnóstico, muitas vezes, é tardio, já que a mamografia pode não abordar adequadamente o tecido glandular. Incidências adicionais como a oblíqua e a craniocaudal forçada, assim como a ultrassonografia, permitem maior visualização do tecido ectópico. A ressecção da mama acessória com margens livres é o tratamento cirúrgico indicado. Não é necessária mastectomia, uma vez que a mama homolateral não está comprometida. A biópsia do linfonodo sentinela é uma alternativa viável na ausência de comprometimento ganglionar.
5
Zagrebelny, S. V., S. I. Kavry e D. O. Skorobogatov. "Estimation of the number, age and sex structure, and seasonal mortality rate of Pacific walruses, Odobenus rosmarus divergens, on the Cape Vankarem coastal haulout in 2017". In Marine mammals of the Holarctic. Marine Mammal Council, 2019. http://dx.doi.org/10.35267/978-5-9904294-0-6-2019-1-121-127.
Testo completo
6
Raimundo, Cecília Daher Ribeiro, Samara Carvalho Perfete, Raphaella dos Santos Maia Crud, Tereza Maria Pereira Fontes, Kátia Alvim Mendonça e Roberto Luiz Carvalhosa dos Santos. "Mastite granulomatosa idiopática". In 46º Congresso da SGORJ e Trocando Ideias XXV. Zeppelini Editorial e Comunicação, 2022. http://dx.doi.org/10.5327/jbg-0368-1416-2022132s1031.
Testo completoAbstract (sommario):
Introdução: A mastite granulomatosa idiopática é uma doença inflamatória benigna e rara da mama de etiologia desconhecida, não responsiva a antibioticoterapia convencional, mas que pode estar associada a alguns agentes etiológicos, como Staphylococcus aureus em 13% dos casos. Relato de caso: Paciente de 27 anos foi encaminhada ao hospital com quadro de mastite crônica (evolução de cinco meses), com formação de abscessos e drenagens espontâneas, sem resposta terapêutica com o uso de cefalexina. Havia tido três gestações e amamentado por poucos dias cada filho. Ao exame clínico das mamas em 21 de julho de 2021: ambas tinham mamilo invertido, a direita era maior que a esquerda e apresentava duas fístulas em fase de cicatrização em quadrante inferior lateral e área de flutuação com sinais logísticos medindo 6 cm na união dos quadrantes superiores da mama aumentada. O exame revelou múltiplos nódulos heterogêneos na mama direita, medindo o maior 3,3 × 1,4 cm e localizando-se no quadrante superior lateral. Observou-se ainda um nódulo de natureza mista (cístico e sólido) na união dos quadrantes mediais da mesma mama, medindo 9,2 × 0,9 cm. Foi realizada a drenagem do abscesso e o material foi enviado para cultura e antibiograma e exame citológico. No acompanhamento da paciente, ela não respondeu ao tratamento com clindamicina 600 mg associado a metronidazol. Diante do resultado da cultura inespecífica (estafilococos áureos) foi prescrita rifampicina por apresentar a menor concentração inibitória (MIC≤0,03). Nesse dia foi realizada core biopsy, solicitaram-se exames para a pesquisa de tuberculose e de Mycobacterium tuberculosis na secreção mamária. O resultado da core biopsy revelou ausência de malignidade. Ao exame clínico, a paciente começava a apresentar melhora, o que nos fez manter a rifampicina. Ela retornou com melhora clínica do quadro e todos os exames de pesquisa de tuberculose negativos. Após manter a medicação por quatro meses, retornou com resolução completa do quadro inflamatório, com cicatrização das fístulas e não percepção, à palpação, das nodulações na mama direita. Conclusão: A tuberculose mamária deve ser considerada no diagnóstico diferencial de qualquer caso de massa mamária dolorosa, mastite ou abscesso mamário que pareça refratário à terapia convencional, sobretudo em áreas endêmicas de tuberculose. Seu reconhecimento e diferenciação de uma patologia maligna da mama é absolutamente necessária. O diagnóstico baseia-se na suspeita clínica e nos achados histopatológicos. Em algumas situações a cultura específica para BK não detecta o bacilo, e a necessidade de terapia com antituberculínicos impõe-se. No caso de nossa paciente, houve regressão do processo infeccioso e das fístulas apenas com a rifampicina por quatro meses.
7
Plata, C. A., M. C. Quintero e J. M. Cordovez. "The effect of atmospheric CO2 on mammal's ventilatory rate". In 2013 Pan American Health Care Exchanges (PAHCE). IEEE, 2013. http://dx.doi.org/10.1109/pahce.2013.6568216.
Testo completo
8
Kamal, Ahmed. "Heart rate variability analysis before and during exposing to low pulsed microwaves in mammals". In 2007 IEEE 33rd Annual Northeast Bioengineering Conference. IEEE, 2007. http://dx.doi.org/10.1109/nebc.2007.4413311.
Testo completo
9
Pacheco, Aryane Ferraz Cardoso. "Apresentação clínica, técnicas diagnósticas e manejo terapêutico no tumor filoide". In 44° Congresso da SGORJ - XXIII Trocando Ideias. Zeppelini Editorial e Comunicação, 2020. http://dx.doi.org/10.5327/jbg-0368-1416-2020130210.
Testo completoAbstract (sommario):
Introdução: O tumor filoide da mama é uma neoplasia fibroepitelial rara, responsável por menos de 1% dos tumores de mama e incide geralmente em mulheres de 35 a 55 anos. Diferentes estudos o relacionam à rápida globalização, ao sedentarismo, às dietas inadequadas e ao consumo de tabaco e álcool. O tumor filoide pode ser classificado como benigno, limítrofe ou maligno, dependendo do grau de celularidade do estroma, atipia, contagem mitótica e a natureza das bordas do tumor. Objetivos: Relatar a apresentação clínica, as possíveis técnicas diagnósticas e o manejo terapêutico mais recente realizado em casos de tumor filoide e, assim, orientar a classe médica sobre a forma de abordar essa patologia. Material e Métodos: Revisão sistemática retrospectiva da literatura usando os principais bancos de dados on-line. Foram investigadas diferentes publicações sobre tumor filoide, com clínica, abordagem diagnóstica e manejo. Resultados e Conclusão: Os tumores filoides geralmente são indolores, manifestam-se como uma massa mamária lisa, móvel, com bordas bem definidas, de consistência firme. Seu crescimento é lento no início, mas acelera à medida que avança, e é rara a disseminação linfática. Seu diagnóstico pode ser por meio do exame clínico das mamas, quando a massa se torna perceptível ao exame físico. A abordagem inicial é feita por mamografia, mas não permite diferenciação de um fibroadenoma, por isso é feito o diagnóstico histopatológico por biópsia com agulha grossa. A alta celularidade estromal diferencia o tumor do fibroadenoma. O diagnóstico precoce favorece o estadiamento e o tratamento adequado com bom prognóstico. Atualmente, o manejo recomendado é o tratamento cirúrgico, realizando a ressecção do tumor com margens ≥10 mm, pois o tumor filoide não responde bem à terapia sistêmica. Recomenda-se um período de acompanhamento rigoroso, em razão do risco de recorrência.
10
Motta, Leonardo França, Kiara de Medeiros Braga Cruz Pessanha, Polyana de Paula Mendes Machado, Thaís Ribeiro Melo e Juliana Batista Siqueira. "Diagnóstico desafiador de tumor desmoide de mama: um relato de caso". In 44° Congresso da SGORJ - XXIII Trocando Ideias. Zeppelini Editorial e Comunicação, 2020. http://dx.doi.org/10.5327/jbg-0368-1416-2020130240.
Testo completoAbstract (sommario):
Introdução: Os tumores desmoides são tumores benignos, com proliferação fibroblástica do tecido conjuntivo do músculo, fáscia e aponeurose. Representam apenas 0,2% dos tumores de mama, acometendo mais comumente a faixa etária da adolescência até os 30 anos. Esses tumores são classificados de acordo com a localização em extra-abdominal, abdominal e intra-abdominal, sendo a forma intra-abdominal a mais prevalente. A expressão clínica desses tumores são compatíveis com algumas neoplasias, podendo apresentar-se como massas firmes, móveis e indolores, estando presente ou não a retração da mama e do mamilo ou edema cutânea. Na mamografia em geral, pode haver a mimetização de lesões malignas da mama, ou então encontramos um resultado inconclusivo, como BIRADS 0 (zero). Diante de tantas semelhanças com neoplasias malignas da mama, o diagnóstico do tumor desmoide se torna desafiador. Objetivo: Relatar o caso de uma paciente com difícil diagnóstico de um tumor raro de mama. Métodos: As informações foram obtidas por meio do acompanhamento da paciente, do diagnóstico histopatológico, da imagem fotográfica da lesão, além de revisão de prontuário e pesquisa bibliográfica nas bases de dados: Scientific Electronic Library Online (SciELO), PubMed, Google Scholar e Literatura Latino-americana e do Caribe em Ciências da Saúde (LILACS). Resultados: O.R.A.R., 58 anos, procurou o serviço de Mastologia em julho de 2018 em razão da tumoração de mama esquerda de crescimento rápido. Aventou-se a hipótese diagnóstica de tumor filoide. Solicitada mamografia BIRADS 0 e ultrassonografia de mama cujo resultado foi BIRADS IV. Prosseguiu a investigação com core biópsia, sendo o resultado histopatológico favorável para fibromatose mamária, necessitando, contudo, de diagnóstico diferencial com carcinoma metaplásico. A imuno-histoquímica direcionou para o diagnóstico de fibromatose desmoide. Diante do resultado, optou-se por prosseguir a investigação com mastectomia simples. O resultado do histopatológico foi compatível com neoplasia de células fusiformes, e a imuno-histoquímica, com tumor desmoide de mama. Após quatro meses da cirurgia, houve recidiva da lesão, que ocorreu de maneira rápida com evolução agressiva. Não havendo tecido para uma nova cirurgia, optou-se por tratamento hormonioterápico, radioterápico e quimioterápico, porém sem resposta, e a paciente veio a óbito. Conclusão: Os tumores desmoides, apesar de representarem apenas 0,2% dos tumores de mama e serem classificados como benignos, são localmente agressivos, possuindo alta recorrência local, mesmo após tratamento adequado com excisão completa. Importante, contudo, ressaltar que não cursam com metástases, necessitando repensar o diagnóstico em casos de disseminação à distância. Diante disso, é essencial que o diagnóstico seja preciso e rápido para que o tratamento seja eficaz, mantendo a paciente sob acompanhamento para identificação precoce de recidivas locais.
Rapporti di organizzazioni sul tema "Rare mamals"
1
Clevenger, Anthony P., e Adam T. Ford. A before-after-control-impact study of wildlife fencing along a highway in the Canadian Rocky Mountains. Nevada Department of Transportation, febbraio 2022. http://dx.doi.org/10.15788/ndot2022.02.
Testo completoAbstract (sommario):
Wildlife exclusion fencing has become a standard component of highway mitigation systems designing to reduce collisions with large mammals. Past work on the effectiveness of exclusion fencing has relied heavily on control-impact (i.e., space-for-time substitutions) and before-after study designs. These designs limit inference and may confound the effectiveness of mitigation with co-occurring process that also change the rate of collisions. We used a replicated before-after-control-impact study design to assess fencing effectiveness along the Trans-Canada Highway in the Rocky Mountains of Canada. We found that collisions declined for common ungulates species (elk, mule deer and white-tailed deer) by up to 96% but not for large carnivores. The weak response of carnivores is likely due to combination of fence intrusions and low sample sizes. When accounting for background changes in collision rates observed at control sites, naïve estimates of fencing effectiveness declined by 6% at one site to 90% and increased by 10% at another to a realized effectiveness of 82%. When factoring in the cost of ungulate collisions to society as a whole, fencing provided a net economic gain within 1 year of construction. Over a 10-year period, fencing would provide a net economic gain of >$500,000 per km in reduced collisions. In contrast, control site may take upwards of 90 years before the background rates of collisions decline to a break even point. Our study highlights the benefits of long-term monitoring of road mitigation projects and provides evidence of fencing effectiveness for reducing wildlife-vehicle collisions involving large mammals.
2
Funkenstein, Bruria, e Shaojun (Jim) Du. Interactions Between the GH-IGF axis and Myostatin in Regulating Muscle Growth in Sparus aurata. United States Department of Agriculture, marzo 2009. http://dx.doi.org/10.32747/2009.7696530.bard.
Testo completoAbstract (sommario):
Growth rate of cultured fish from hatching to commercial size is a major factor in the success of aquaculture. The normal stimulus for muscle growth in growing fish is not well understood and understanding the regulation of muscle growth in fish is of particular importance for aquaculture. Fish meat constitutes mostly of skeletal muscles and provides high value proteins in most people's diet. Unlike mammals, fish continue to grow throughout their lives, although the size fish attain, as adults, is species specific. Evidence indicates that muscle growth is regulated positively and negatively by a variety of growth and transcription factors that control both muscle cell proliferation and differentiation. In particular, growth hormone (GH), fibroblast growth factors (FGFs), insulin-like growth factors (IGFs) and transforming growth factor-13 (TGF-13) play critical roles in myogenesis during animal growth. An important advance in our understanding of muscle growth was provided by the recent discovery of the crucial functions of myostatin (MSTN) in controlling muscle growth. MSTN is a member of the TGF-13 superfamily and functions as a negative regulator of skeletal muscle growth in mammals. Studies in mammals also provided evidence for possible interactions between GH, IGFs, MSTN and the musclespecific transcription factor My oD with regards to muscle development and growth. The goal of our project was to try to clarify the role of MSTNs in Sparus aurata muscle growth and in particular determine the possible interaction between the GH-IGFaxis and MSTN in regulating muscle growth in fish. The steps to achieve this goal included: i) Determining possible relationship between changes in the expression of growth-related genes, MSTN and MyoD in muscle from slow and fast growing sea bream progeny of full-sib families and that of growth rate; ii) Testing the possible effect of over-expressing GH, IGF-I and IGF-Il on the expression of MSTN and MyoD in skeletal muscle both in vivo and in vitro; iii) Studying the regulation of the two S. aurata MSTN promoters and investigating the possible role of MyoD in this regulation. The major findings of our research can be summarized as follows: 1) Two MSTN promoters (saMSTN-1 and saMSTN-2) were isolated and characterized from S. aurata and were found to direct reporter gene activity in A204 cells. Studies were initiated to decipher the regulation of fish MSTN expression in vitro using the cloned promoters; 2) The gene coding for saMSTN-2 was cloned. Both the promoter and the first intron were found to be polymorphic. The first intron zygosity appears to be associated with growth rate; 3) Full length cDNA coding for S. aurata growth differentiation factor-l I (GDF-II), a closely related growth factor to MSTN, was cloned from S. aurata brain, and the mature peptide (C-terminal) was found to be highly conserved throughout evolution. GDF-II transcript was detected by RT -PCR analysis throughout development in S. aurata embryos and larvae, suggesting that this mRNA is the product of the embryonic genome. Transcripts for GDF-Il were detected by RT-PCR in brain, eye and spleen with highest level found in brain; 4) A novel member of the TGF-Bsuperfamily was partially cloned from S. aurata. It is highly homologous to an unidentified protein (TGF-B-like) from Tetraodon nigroviridisand is expressed in various tissues, including muscle; 5) Recombinant S. aurata GH was produced in bacteria, refolded and purified and was used in in vitro and in vivo experiments. Generally, the results of gene expression in response to GH administration in vivo depended on the nutritional state (starvation or feeding) and the time at which the fish were sacrificed after GH administration. In vitro, recombinantsaGH activated signal transduction in two fish cell lines: RTHI49 and SAFI; 6) A fibroblastic-like cell line from S. aurata (SAF-I) was characterized for its gene expression and was found to be a suitable experimental system for studies on GH-IGF and MSTN interactions; 7) The gene of the muscle-specific transcription factor Myogenin was cloned from S. aurata, its expression and promoter activity were characterized; 8) Three genes important to myofibrillogenesis were cloned from zebrafish: SmyDl, Hsp90al and skNAC. Our data suggests the existence of an interaction between the GH-IGFaxis and MSTN. This project yielded a great number of experimental tools, both DNA constructs and in vitro systems that will enable further studies on the regulation of MSTN expression and on the interactions between members of the GHIGFaxis and MSTN in regulating muscle growth in S. aurata.
3
El Halawani, Mohamed, e Israel Rozenboim. Temperature Stress and Turkey Reproduction. United States Department of Agriculture, maggio 2002. http://dx.doi.org/10.32747/2002.7570546.bard.
Testo completoAbstract (sommario):
High temperature stress is of major concern to turkey producers in Israel and the United States. The decline in the rate of egg production at high environmental temperature is well recognized, but the neuroendocrinological basis is not understood. Our objectives were: 1) to characterize the hypothalamo-hypophyseal axis involvement in the mechanism(s) underlying the detrimental effect of heat stress on reproduction, and 2) to establish procedures that alleviate the damaging effect of heat stress on reproduction. Heat stress (40oC, Israel; 32oC, U.S.) caused significant reduction in egg production, which was restored by VIP immunoneutralization. The decline in egg production did not appear to be entirely related to the expression of incubation behavior due to the rise in circulating PRL in stressed birds. Heat stress was found to increase circulating PRL in ovariectomized turkeys independent of the reproductive stage. Active immunization against VIP was shown for the first time to up-regulate LHb and FSHb subunit mRNA contents. These findings taken together with the results that the heat stress-induced decline in egg production may not be dependent upon the reproductive stage, lead to the suggestion that the detrimental effect of heat stress on reproductive performance may be in part mediated by VIP acting directly on the GnRH/gonadotropin system. Inhibin (INH) immunoneutralization has been shown to enhance FSH secretion and induces ovulation in mammals. It is hypothesized that immunization of heat-stressed turkeys against INH will increase levels of circulating FSH and the number of preovulating follicles which leads to improved reproductive performance. We have cloned and expressed turkey INH-a and INH-bA. Active immunization of turkey hens with rtINH-a increased pituitary FSH-b subunit mRNA and the number of non-graded preovulatory yellow follicles, but no significant increase in egg production was observed.
4
Gottlieb, Yuval, e Bradley A. Mullens. Might Bacterial Symbionts Influence Vectorial Capacity of Biting Midges for Ruminant Viruses? United States Department of Agriculture, settembre 2010. http://dx.doi.org/10.32747/2010.7699837.bard.
Testo completoAbstract (sommario):
- Original objectives and revision: The feasibility study performed in the last year was aimed at determining the symbiotic profiles of eight selected Culicoidesspecies in Israel and the USA by: Comparing bacterial communities among geographic populations of primary bluetongue virus (BTV) vectors. Comparing bacterial communities between adults of field-collected, mammal-feeding BTV vectors and non-vectors. Comparing bacterial communities within and between mammal feeders and bird feeders, with special attention to species with unique immature habitats. We made an effort to collect the eight species during the beginning of the project, however, due to the short available collection season, and the significant changes in habitats available for Israeli Culicoides, we initially determined the symbiotic profile of five species: two BTV vectors (C. sonorensis, C. imicola), one mammal feeders with unknown vectoring ability (C. schultzei), one bird feeder (C. crepuscularis), and one unique habitat species (C. cacticola). In addition, upon preliminary symbiont identification we focused our effort on relevant specific symbionts. Background: Biting midges (Culicoides, Diptera: Ceratopogonidae) are vectors of many major viral diseases affecting farm animals, including BT, which is listed among the most damaging by the World Organization for Animal Health (OIE) and has recently emerged in completely unexpected areas (Northern Europe). One of the strategies to reduce the vectorial capacity of insect vectors is by manipulating their specific symbionts either to affect the vector species or to influence performance of the disease agent within it. Despite significant efforts to elucidate the vectorial capacity of certain Culicoidesspecies, and the critical basis of variability in infection, almost no attention has been given to symbiotic interactions between the vector and its bacterial tenants. It is now established that bacterial symbionts have major influences on their host biology, and may interact with disease agents vectored by their hosts. - Major conclusions, solutions, achievements: During the feasibility project we have found two major bacterial symbionts in Israeli and American Culicoides. In Israel we discovered that C. imicola, a known vector of BT, and C. schultzeigp. a suspected vector of BT, carry the symbiotic bacterium Cardinium, a reproductive manipulator symbiont. In C. imicolathe infection rate was close to 50%, and in C. schultzeiit was lower, and restricted to one of two species within Schultzeigroup. In 3 American species (C. sonorensis, C. crepuscularis, C. cacticola) we found the bacterium Burkholderiasp. In all species tested we have also found other bacterial species in diverse quantities and frequencies. - Implications, both scientific and agricultural: Finding specific symbionts in Culicoidesvector species is the first step in developing symbiont based control (SBC) strategies. Both identified symbionts are known from other insects, and Cardiniumis also known as a reproductive manipulator that can cause cytoplasmic incompatibility, an important phenomenon that can be used for spreading desired traits in infected populations. The role of the symbionts in Culicoideshost can be target for manipulation to reduce the vectorial capacity of the host by either changing its fitness so that it is unable to serve as a vector, or by directly changing the symbiont in a way that will affect the performance of the disease agent in its vector. Since Burkholderiaperhaps can be cultured independently of the host, it is a promising candidate for the later option. Thus, we have now opened the door for studying the specific interactions between symbionts and vector species.
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Wackett, Lawrence, Raphi Mandelbaum e Michael Sadowsky. Bacterial Mineralization of Atrazine as a Model for Herbicide Biodegradation: Molecular and Applied Aspects. United States Department of Agriculture, gennaio 1999. http://dx.doi.org/10.32747/1999.7695835.bard.
Testo completoAbstract (sommario):
Atrazine is a broadly used herbicide in agriculture and it was used here as a model to study the biodegradation of herbicides. The bacterium Pseudomonas sp. ADP metabolizes atrazine to carbon dioxide and ammonia and chloride. The genes encoding atrazine catabolism to cyanuric acid were cloned and expressed in Escherichia coli. The genes were designated atzA, atzB and atzC. Each gene was sequenced. The enzyme activities were characterized. AtzA is atrazine chlorohydrolase which takes atrazine to hydroxyatrizine. AtzB is hydroxyatrazine N-ethylaminohydrolase which produces N-isopropylammelide and N-ethylamine. AtzC is N-isopropylammelide N-isopropylaminohydrolase which produces cyanuric acid and N-isopropylamine. Each product was isolated and characterized to confirm their identity by chromatography and mass spectrometry. Sequence analysis indicated that each of the hydrolytic enzymes AtzA, AtzB and AtzC share identity which the aminohydrolase protein superfamily. Atrazine chlorohydrolase was purified to homogeneity. It was shown to have a kcat of 11 s-1 and a KM of 150 uM. It was shown to require a metal ion, either Fe(II), Mn(II) or Co(II), for activity. The atzA, atzB and atzC genes were shown to reside on a broad-host range plasmid in Pseudomonas sp. ADP. Six other recently isolated atrazine-degrading bacteria obtained from Europe and the United States contained homologs to the atz genes identified in Pseudomonas sp. ADP. The identity of the sequences were very high, being greater than 98% in all pairwise comparisons. This indicates that many atrazine-degrading bacteria worldwide metabolize atrazine via a pathway that proceeds through hydroxyatrazine, a metabolite which is non-phytotoxic and non-toxic to mammals. Enzymes were immobilized and used for degradation of atrazine in aqueous phases. The in-depth understanding of the genomics and biochemistry of the atrazine mineralization pathway enabled us to study factors affecting the prevalence of atrazine degradation in various agricultural soils under conservative and new agricultural practices. Moreover, Pseudomonas sp. ADP and/or its enzymes were added to atrazine-contaminated soils, aquifers and industrial wastewater to increase the rate and extent of atrazine biodegradation above that of untreated environments. Our studies enhance the ability to control the fate of regularly introduced pesticides in agriculture, or to reduce the environmental impact of unintentional releases.
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Funkenstein, Bruria, e Cunming Duan. GH-IGF Axis in Sparus aurata: Possible Applications to Genetic Selection. United States Department of Agriculture, novembre 2000. http://dx.doi.org/10.32747/2000.7580665.bard.
Testo completoAbstract (sommario):
Many factors affect growth rate in fish: environmental, nutritional, genetics and endogenous (physiological) factors. Endogenous control of growth is very complex and many hormone systems are involved. Nevertheless, it is well accepted that growth hormone (GH) plays a major role in stimulating somatic growth. Although it is now clear that most, if not all, components of the GH-IGF axis exist in fish, we are still far from understanding how fish grow. In our project we used as the experimental system a marine fish, the gilthead sea bream (Sparus aurata), which inhabits lagoons along the Mediterranean and Atlantic coasts of Europe, and represents one of the most important fish species used in the mariculture industry in the Mediterranean region, including Israel. Production of Sparus is rapidly growing, however, in order for this production to stay competitive, the farming of this fish species has to intensify and become more efficient. One drawback, still, in Sparus extensive culture is that it grows relatively slow. In addition, it is now clear that growth and reproduction are physiological interrelated processes that affect each other. In particular sexual maturation (puberty) is known to be closely related to growth rate in fish as it is in mammals, indicating interactions between the somatotropic and gonadotropic axes. The goal of our project was to try to identify the rate-limiting components(s) in Sparus aurata GH-IGF system which might explain its slow growth by studying the ontogeny of growth-related genes: GH, GH receptor, IGF-I, IGF-II, IGF receptor, IGF-binding proteins (IGFBPs) and Pit-1 during early stages of development of Sparus aurata larvae from slow and fast growing lines. Our project was a continuation of a previous BARD project and could be divided into five major parts: i) obtaining additional tools to those obtained in the previous project that are necessary to carry out the developmental study; ii) the developmental expression of growth-related genes and their cellular localization; iii) tissue-specific expression and effect of GH on expression of growth-related genes; iv) possible relationship between GH gene structure, growth rate and genetic selection; v) the possible role of the IGF system in gonadal development. The major findings of our research can be summarized as follows: 1) The cDNAs (complete or partial) coding for Sparus IGFBP-2, GH receptor and Pit-1 were cloned. Sequence comparison reveals that the primary structure of IGFBP-2 protein is 43-49% identical to that of zebrafish and other vertebrates. Intensive efforts resulted in cloning a fragment of 138 nucleotides, coding for 46 amino acids in the proximal end of the intracellular domain of GH receptor. This is the first fish GH receptor cDNA that had been cloned to date. The cloned fragment will enable us to complete the GH - receptor cloning. 2) IGF-I, IGF-II, IGFBP-2, and IGF receptor transcripts were detected by RT-PCR method throughout development in unfertilized eggs, embryos, and larvae suggesting that these mRNAs are products of both the maternal and the embryonic genomes. Preliminary RT-PCR analysis suggest that GH receptor transcript is present in post-hatching larvae already on day 1. 3) IGF-1R transcripts were detected in all tissues tested by RT-PCR with highest levels in gill cartilage, skin, kidney, heart, pyloric caeca, and brain. Northern blot analysis detected IGF receptor only in gonads, brain and gill cartilage but not in muscle; GH increased slightly brain and gill cartilage IGF-1R mRNA levels. 4) IGFBP-2 transcript were detected only in liver and gonads, when analyzed by Northern blots; RT-PCR analysis revealed expression in all tissues studied, with the highest levels found in liver, skin, gonad and pyloric caeca. 5) Expression of IGF-I, IGF-II, IGF-1R and IGFBP-2 was analyzed during gonadal development. High levels of IGF-I and IGFBP-2 expression were found in bisexual young gonads, which decreased during gonadal development. Regardless of maturational stage, IGF-II levels were higher than those of IGF-L 6) The GH gene was cloned and its structure was characterized. It contains minisatellites of tandem repeats in the first and third introns that result in high level of genetic polymorphism. 7) Analysis of the presence of IGF-I and two types of IGF receptor by immunohistochemistry revealed tissue- and stage-specific expression during larval development. Immunohistochemistry also showed that IGF-I and its receptors are present in both testicular and ovarian cells. Although at this stage we are not able to pinpoint which is the rate-limiting step causing the slow growth of Sparus aurata, our project (together with the previous BARD) yielded a great number of experimental tools both DNA probes and antibodies that will enable further studies on the factors regulating growth in Sparus aurata. Our expression studies and cellular localization shed new light on the tissue and developmental expression of growth-related genes in fish.
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Gothilf, Yoav, Roger Cone, Berta Levavi-Sivan e Sheenan Harpaz. Genetic manipulations of MC4R for increased growth and feed efficiency in fish. United States Department of Agriculture, gennaio 2016. http://dx.doi.org/10.32747/2016.7600043.bard.
Testo completoAbstract (sommario):
The hypothalamic melanocortin system plays a central role in the regulation of food consumption and energy homeostasis in mammals. Accordingly, our working hypothesis in this project was that genetic editing of the mc4r gene, encoding Melanocortin Receptor 4 (MC4R), will enhance food consumption, feed efficiency and growth in fish. To test this hypothesis and to assess the utility of mc4r editing for the enhancement of feed efficiency and growth in fish, the following objectives were set: Test the effect of the mc4r-null allele on feeding behavior, growth, metabolism and survival in zebrafish. Generate mc4r-null alleles in tilapia and examine the consequences for growth and survival, feed efficiency and body composition. Generate and examine the effect of naturally-occurring mc4r alleles found in swordfish on feeding behavior, growth and survival in zebrafish. Define the MC4R-mediated and MC4R-independent effects of AgRP by crossing mc4r- null strains with fish lacking AgRP neurons or the agrpgene. Our results in zebrafish did not support our hypothesis. While knockout of the agrpgene or genetic ablation of hypothalamic AgRP neurons led to reduced food intake in zebrafish larvae, knockout (KO) of the mc4r gene not only did not increase the rate of food intake but even reduced it. Since Melanocortin Receptor 3 (MC3R) has also been proposed to be involved in hypothalamic control of food intake, we also tested the effectofmc3r gene KO. Again, contrary to our hypothesis, the rate of food intake decreased. The next step was to generate a double mutant lucking both functional MC3R and MC4R. Again, the double KO exhibited reduced food intake. Thus, the only manipulation within the melanocortin system that affected food intake in consistent with the expected role of the system was seen in zebrafish larvae upon agrpKO. Interestingly, despite the apparent reduced food intake in the larval stage, these fish grow to be of the same size as wildtype fish at the adult stage. Altogether, it seems that there is a compensatory mechanism that overrides the effect of genetic manipulations of the melanocortin system in zebrafish. Under Aim 3, we introduced the Xna1, XnB1l, and XnB2A mutations from the Xiphophorus MC4R alleles into the zebrafish MC4R gene. We hypothesized that these MC4R mutations would act as dominant negative alleles to increase growth by suppressing endogenous MC4R activity. When we examined the activity of the three mutant alleles, we were unable to document any inhibition of a co-transfected wild type MC4R allele, hence we did not introduce these alleles into zebrafish. Since teleost fish possess two agrpgenes we also tested the effect of KO of the agrp2 gene and ablation of the AgRP2 cells. We found that the AgRP2 system does not affect food consumption but may rather be involved in modulating the stress response. To try to apply genetic editing in farmed fish species we turned to tilapia. Injection of exogenous AgRP in adult tilapia induced significant changes in the expression of pituitary hormones. Genetic editing in tilapia is far more complicated than in zebrafish. Nevertheless, we managed to generate one mutant fish carrying a mutation in mc4r. That individual died before reaching sexual maturity. Thus, our attempt to generate an mc4r-mutant tilapia line was almost successful and indicate out non-obvious capability to generate mutant tilapia.