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Artykuły w czasopismach na temat "Introduced birds"
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Baker, Jack, Kerinne J. Harvey i Kris French. "Threats from introduced birds to native birds". Emu - Austral Ornithology 114, nr 1 (marzec 2014): 1–12. http://dx.doi.org/10.1071/mu12122.
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White, Douglas W., i Edmund W. Stiles. "Bird dispersal of fruits of species introduced into eastern North America". Canadian Journal of Botany 70, nr 8 (1.08.1992): 1689–96. http://dx.doi.org/10.1139/b92-208.
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We compared bird use of fruits of introduced and native plant species to explore the roles of coevolution, ecological fitting, and chance in shaping seed dispersal interactions. Of 45 bird-dispersed species recorded at three sites in central New Jersey, 15 (33%) were nonnative. In fall samples from seed traps and fecal droppings, introduced species accounted for 0.4–14% of fruit biomass overall and 3 – 30% of the biomass of low-quality fruits. Although absolute fruit use declined from fall to winter, relative use of introduced species increased seasonally to as high as half of winter fruit biomass. Heavy use of non-native fruits appears recent; introductions accounted for only 2% of plant species occurrences in fall and winter records of stomach contents for nine passerine species in New England and mid-Atlantic states between 1881 and 1950. Introduced fruits with fall maturation, low-quality pulp, and high durability now rival native species in fruit diets of birds in late fall and winter. The success of introductions demonstrates coadaptation through ecological fitting of preadapted partners; nevertheless, the predominant use of introduced fruits after peak bird migration suggests that introduced fruits may be less well matched to local dispersal opportunities than native ones. Key words: birds, coevolution, fruits, introductions.
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Sjöberg, Göran. "Genetic characteristics of introduced birds and mammals". Wildlife Biology 2, nr 1 (styczeń 1996): 159–64. http://dx.doi.org/10.2981/wlb.1996.014.
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Navas, Jorge. "Exotic birds introduced and naturalized in Argentina". Revista del Museo Argentino de Ciencias Naturales 4 (2002): 191–202. http://dx.doi.org/10.22179/revmacn.4.12.
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Blackburn, Tim M., i Richard P. Duncan. "Determinants of establishment success in introduced birds". Nature 414, nr 6860 (listopad 2001): 195–97. http://dx.doi.org/10.1038/35102557.
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Briskie, James V. "Introduced Birds as Model Systems for the Conservation of Endangered Native Birds". Auk 123, nr 4 (październik 2006): 949–57. http://dx.doi.org/10.2307/25150210.
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Briskie, James V. "INTRODUCED BIRDS AS MODEL SYSTEMS FOR THE CONSERVATION OF ENDANGERED NATIVE BIRDS". Auk 123, nr 4 (2006): 949. http://dx.doi.org/10.1642/0004-8038(2006)123[949:ibamsf]2.0.co;2.
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Briskie, James V. "Introduced Birds as Model Systems for the Conservation of Endangered Native Birds". Auk 123, nr 4 (1.10.2006): 949–57. http://dx.doi.org/10.1093/auk/123.4.949.
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Blackburn, Tim M., i Phillip Cassey. "Are introduced and re-introduced species comparable? A case study of birds". Animal Conservation 7, nr 4 (listopad 2004): 427–33. http://dx.doi.org/10.1017/s1367943004001647.
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Ayre, Bronwyn M., David G. Roberts, Ryan D. Phillips, Stephen D. Hopper i Siegfried L. Krauss. "Effectiveness of native nectar-feeding birds and the introduced Apis mellifera as pollinators of the kangaroo paw, Anigozanthos manglesii (Haemodoraceae)". Australian Journal of Botany 68, nr 1 (2020): 14. http://dx.doi.org/10.1071/bt19097.
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Plants pollinated by vertebrates are often visited by native and exotic insects foraging for pollen and nectar. We compared flower visitation rates, foraging behaviour, and the contribution to reproduction of nectar-feeding birds and the introduced honeybee Apis mellifera in four populations of the bird-pollinated Anigozanthos manglesii (Haemodoraceae). The behaviour of floral visitors was quantified with direct observations and motion-triggered and hand-held cameras. Pollinator access to flowers was manipulated by enclosure in netting to either exclude all visitors or to exclude vertebrate visitors only. Apis mellifera was the only insect observed visiting flowers, and the most frequent flower visitor, but primarily acted as a pollen thief. Although birds visited A. manglesii plants only once per week on average, they were 3.5 times more likely to contact the anther or stigma as foraging honeybees. Exclusion of birds resulted in 67% fewer fruits and 81% fewer seeds than flowers left open and unmanipulated. Unnetted flowers that were open to bird and insect pollinators showed pollen-limitation and a large variation in reproductive output within and between sites. Although honeybees have been shown to pollinate other Australian plants, compared to birds, they are highly inefficient pollinators of A. manglesii.
Rozprawy doktorskie na temat "Introduced birds"
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Allen, Sophy Elizabeth. "The effect of population bottleneck size on parasitic load and immunocompetence of introduced birds in New Zealand". Thesis, University of Canterbury. Biological Sciences, 2008. http://hdl.handle.net/10092/1951.
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I investigated parasitic infection and immunocompetence in populations of introduced bird species in New Zealand (NZ) that had experienced a range of population bottlenecks (11-808 individuals), and compared these parameters to non-bottlenecked conspecifics in the United Kingdom (UK). My aims were two-fold; firstly to assess if population bottlenecks are linked to increased parasite loads and/or decreased immunocompetence, and secondly, to assess at what severity of bottleneck these effects become evident. I found that ectoparasite load (chewing lice, Order: Phthiraptera, Sub-Orders: Amblycera & Ischnocera) was significantly higher in the more severely bottlenecked species in NZ than in the UK, whilst this difference became non-significant at more moderate bottlenecks. The difference was mainly driven by the Sub-Order Amblycera. The prevalence of avian malaria (Plasmodium spp.) was significantly negatively correlated to bottleneck size within NZ, after controlling for body mass. Total leucocyte and differential lymphocyte counts were elevated in the less bottlenecked species that were infected with malaria, whilst the populations at the more severe end of the bottleneck spectrum did not exhibit such a response. Furthermore, heterophil/lymphocyte (HL) ratio (a parameter used as an indicator of environmental and/or immunological stress), was significantly raised in the more bottlenecked species when compared to their UK counterparts, and this difference was correlated with the size of the bottleneck. Immunocompetence was further assessed by the experimental challenge of six introduced birds species in NZ with the mitogen phytohaemagglutinin (PHA). Immune response to PHA was significantly correlated to bottleneck size, but in the opposite direction to that predicted; immune response was greater in the more bottlenecked species. However, this may be an indication of increased investment in immunity, due to increased parasite and pathogen pressure or differential investment in varying components of the immune system. Finally, the immune response to PHA was compared in nestlings of two species that had experienced very different bottlenecks (70 vs. 653). After controlling for ectoparasitic infestation, I found no difference between the two species; however, this finding may be confounded by interspecific competition. Overall, my findings suggest that more severe population bottlenecks may result in increased susceptibility to pathogens, and impact on the immune system. This has a number of implications for the development of conservation protocols, and future avenues of research are suggested.
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Cassey, Phillip, i n/a. "Comparative Analyses of Successful Establishment Among Introduced Land Birds". Griffith University. Australian School of Environmental Studies, 2002. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030915.094001.
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Humankind has redistributed a large number of species outside their native geographic ranges. Although the majority of introduction attempts fail to establish populations, the cumulative negative effect of successful non-native species has been and will continue to be large. Historical records of land bird introductions provide one of the richest sources of data for testing hypotheses regarding the factors that affect the successful establishment of non-native populations. However, despite comprehensive summaries of global avian introductions dating back two decades only very recent studies have examined the successful establishment of non-native bird species worldwide. It is clear that a non-random pattern exists in the types of land bird species that have been chosen by humans to be introduced outside their native range. Out of the 44 avian families from which species have been chosen for introduction almost 70% of introduction attempts have been from just five families (Phasianidae, Passeridae, Fringillidae, Columbidae, Psittacidae). Notably, these families include game species, insectivorous song birds, and species from the pet trade. It has been hypothesised that the fate of introduced species may be determined in part by heritable characteristics that are shared by closely related taxa. In my analyses, I have used current comparative methods to demonstrate that intrinsic eco-physiological characteristics are significant predictors of the worldwide success of introduced land bird species. The results of my analyses contribute to a greater ecological understanding of the traits that correlate with the successful establishment of non-native species. Notably, the three major conclusions that I have drawn from this thesis are: 1. Non-random patterns of successful establishment exist for introduced land bird taxa that have experienced a repeated number of introduction attempts. This result supports the idea that introduced species have an inherent likelihood of either succeeding or failing to establish non-native populations. 2. Eco-physiological traits are important correlates for determining the variability in introduction outcome for non-native land bird species. With reliable information on introduction attempts and taxa-specific traits predictive models are possible that quantify the outcome of repeated introduction attempts across non-native species. 3. Islands are not universally less resistant than mainland regions to the successful establishment of non-native species. This perception is a reflection of the greater number of introduction attempts to islands rather than an effect of biotic resistance. Any differences in the success of introduction attempts can be attributed largely to differences in the proportion of introductions that have been made across biogeographic regions. I have highlighted that data are accessible for global analyses of the variability in the successful establishment of non-native species. Although establishment success is not a deterministic process, the characteristics of an introduced species can influence the probability of its succeeding. I have shown that with adequate eco-physiological information, and for introduced land bird species at least, this probability can be predicted. These results refute previous suggestions that the stochastic component of species introductions will always overshadow any emerging patterns of successful establishment among non-native populations.
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Pedersen, Simen. "Effects of native and introduced cervids on small mammals and birds". Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15935.
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Cervids are a widespread family of ungulates, native to the Americas, Europe and Asia and introduced to Australia. Densities of cervids have increased in North America, Europe and Japan during the last couple of decades, due to changes in land use, reduced hunting, lack of large carnivores and changes in management practices. Where they occur at high densities, native and introduced cervids may have profound effects on vegetation, causing knock-on effects on other taxa. Cervids are in some instances managed towards changing the local distribution through supplemental feeding. These supplemental feeding stations are causing localized areas of high cervid abundance in the landscape, and may have effects on plants and animal species. In this thesis I investigate how high cervid densities and the practice of supplemental feeding impact birds and small mammals through effects on; 1) food resources, and 2) habitat structure. Utilizing a simulated moose (Alces alces) browsing experiment, I tested how varying moose densities and varying site productivity affects vole preference for bilberry. I found that voles preferred unbrowsed bilberry at low productivity sites, while they preferred lightly browsed bilberry at high productivity sites, I was however unable to explain the preference pattern with the chemical composition of the bilberry. However, moose do impact vole food preferences and this could, depending on the productivity of the site, potentially affect food selection and population dynamics over large geographical areas. Moose browsing pressure and nutrient input gradually decline with distance from supplemental winter feeding stations. I utilized this gradient to test how moose activity affects reproduction in pied flycatchers (Ficedula hypoleuca) and great tits (Parus major). The two species showed contrasting responses to moose feeding stations, great tits preferred to nest away from feeding stations where they showed higher feeding frequency and also produced more fledglings compared to close to feeding stations. Pied flycatchers on the other hand preferred to nest close to feeding stations where they had higher feeding frequency and fledgling mass was higher compared to further away. Hence, for both species moose browsing is affecting food availability that subsequently affects reproductive performance. Moose supplemental feeding stations also changed the habitat for small mammals from dwarf shrub dominated to grass and forb dominated. This did not have any effect on reproductive performance of the small mammals, but it did affect species composition along a gradient from the feeding stations. There was higher abundance of Microtus spp. and common shrews (Sorex araneus) close to feeding stations, while bank voles (Myodes glareoleus) had higher abundance away from feeding stations, the latter however was not statistically significant. Small mammals in Australian coastal heath were generally negatively associated with introduced rusa deer (Cervus timorensis), however one species responded positively to historical densities of rusa deer. It was however not possible to confirm these effects as being due to changes in habitat structure for the small mammals. However they may be explained by qualitative changes in the vegetation or alternatively by direct effects of deer through trampling or predation. Cervids and their management have an impact on other fauna, however the effects vary depending on small mammal and bird species. The effects of cervids also depend on the habitat requirements and foraging preferences of the small mammals and birds. Effects may be mediated through both food resources and habitat structure and are dependent on site productivity and cervid density.
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Burrows, Ben Robert. "Do Severe Genetic Bottlenecks Lead to Greater Reproductive Failure?" Thesis, University of Canterbury. Biological Sciences, 2006. http://hdl.handle.net/10092/1344.
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It is generally accepted that populations which experience severe bottlenecks have a reduction in fitness. One of the most frequently reported fitness costs is increased hatching failure in bottlenecked populations of birds. The mechanism responsible for increased hatching failure is unknown. Research on other animals suggest that reduced population numbers cause unavoidable inbreeding that in turn leads to abnormalities in the gametes. In this thesis I examine some of the possible causes for increased hatching failure in severely bottlenecked populations of introduced birds in New Zealand. I look at three traits identified as a cause for infertility or hatching failure previously and determine whether there is a link with the size of a population s bottleneck. It is possible that reduced numbers of sperm reaching the site of fertilisation is a primary cause of hatching failure. I examined the perivitelline membrane of various species of introduced birds and counted the total number of sperm present to compare to how many would be expected in non-bottlenecked species. Although there was no relationship between the size of the bottleneck and the number of sperm present, all species had lower than expected sperm counts. In many species of mammals, a reduction in the quality of sperm is attributed to inbreeding depression bought about by genetic bottlenecks. I next compared the level of sperm abnormalities, variation in midpiece size sperm, and sperm motility with the size of the bottleneck each species passed through when introduced to New Zealand. There was no significant correlation between either the variation in midpiece size or sperm motility with bottleneck size. However, there was a trend for species that passed through more severe bottlenecks to have a slightly higher level of midpiece size and lower motility. Finally, I examined whether there was a link between abnormalities in the eggshell and the size of the respective bottleneck. There was no significant change in eggshell thickness or any change in the number of pores associated bottleneck size. However, there was a decreased number of round pores in severely bottlenecked species, although the consequences of this are unknown. My findings do not directly link a single cause for increased hatching failure in bottlenecked species of birds, but they do highlight the need for monitoring of reproductive traits in endangered species that have experienced a population bottleneck.
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Debruyne, Christine Anne. "Fluctuating asymmetry and body morphology in relation to population bottlenecks of introduced birds in New Zealand". Thesis, University of Canterbury. Biological Sciences, 2008. http://hdl.handle.net/10092/3326.
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The introduction of exotic bird species to New Zealand (NZ) from the United Kingdom (UK) over 100 years ago unintentionally created an ideal study system to examine potential changes in developmental stability due to bottleneck effects. In this study I measured fluctuating asymmetry (FA; random deviations from symmetry between bilaterally symmetrical traits) in 13 species of introduced birds in NZ. FA has been used for conservation purposes as an early warning system of increased developmental instability (DI; the inability to cope with random genetic or environmental perturbations during development). I evaluated DI using FA in several anatomical external and internal morphological traits, and compared differences in body morphology between introduced and source populations in relation to the bottleneck size. I also examined FA in nestlings in two closely related introduced species that passed through two different-sized population bottlenecks. Differences in FA in relation to bottleneck severity were only observed in external traits. FA in external traits in some NZ populations differed from their UK counterparts, but it was in the opposite direction than predicted. FA in external traits varied significantly across NZ populations of introduced species - the most severe bottlenecks species exhibited higher levels of FA than species that passed through larger bottlenecks. There were no patterns in FA and bottleneck size for skeletal traits, most likely due to differences in environmental and genetic stressors resulting in species- and characterspecific FA relationships. Nestling FA was the same for both species, despite the large difference in bottleneck size. FA did decrease over the nestling period, although not at the same rate for each trait, most likely due to the differing costs of development, functional importance, and other environmental stressors that might influence FA in each trait differently. Overall changes in body morphology occurred in four species introduced to NZ, and all species exhibited some changes in trait morphology but were not related to bottleneck size. Finally, the proportion of deformities (deviations from normal phenotype) was higher in NZ than in UK suggesting passing through a bottleneck increased the probability of abnormalities. Although the associations between FA, body morphology and bottleneck severity are complex, my results confirm that measures of morphology have the potential of being useful indicators of DI in the management of endangered species.
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Taylor, Sabrina S., i n/a. "The genetic and conservation consequences of species translocations in New Zealand saddlebacks and robins". University of Otago. Department of Zoology, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070118.101358.
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Species translocations result in demographic bottlenecks that may produce inbreeding depression and reduce genetic variation through random sampling and drift, an outcome that could decrease long-term fitness and adaptive potential of many New Zealand species. Despite considerable evidence for costs associated with inbreeding and reduced genetic variation, some species have recovered from a small number of individuals and are thriving, perhaps via high growth rates, differential survival of heterozygous individuals or inbreeding avoidance. I examined the genetic consequences of species translocations in saddlebacks (Philesturnus carunculatus) with additional data provided for robins (Petroica australis) where possible. I first assessed whether contemporary genetic variation represented historical levels or a decline following demographic bottlenecks. I then examined whether sequential demographic bottlenecks caused sequential genetic bottlenecks and reviewed whether populations founded with a small number of birds were likely to go extinct. This analysis was followed by an investigation of two mechanisms that may maintain or reduce fitness costs, differential survival of heterozygous individuals and mate choice to avoid genetically similar individuals.
Evidence from museum specimens suggests that low levels of genetic variation in contemporary saddlebacks is no different to historical genetic variation in the only source population, Big South Cape Island. An ancient founding event to Big South Cape Island is probably the cause of severe genetic bottlenecking rather than the demographic bottleneck caused by rats in the 1960s. In robins, genetic variation decreased slightly between museum and contemporary samples suggesting that recent population declines and habitat fragmentation have caused reductions in current levels of genetic variation.
Serial demographic bottlenecks caused by sequential translocations of saddlebacks did not appear to decrease genetic variation. Loss of genetic variation due to random sampling was probably minimized because the low level of genetic variation remaining in the species was probably represented in the number of birds translocated to new islands. Models assessing future loss of genetic variation via drift showed that high growth rates combined with high carrying capacity on large islands would probably maintain existing genetic variation. In contrast, low carrying capacity on small islands would probably result in considerable loss of genetic variation over time. Saddleback populations on small islands may require occasional immigrants to maintain long-term genetic variation.
Saddleback and robin populations established with a small number of founders did not have an increased risk of failure, suggesting that inbreeding was not substantial enough to prevent populations from growing and recovering. However, modelling showed that translocated saddleback and robin populations grow exponentially even when egg failure rates (a measure of inbreeding depression) are extremely high. Although inbreeding depression may be considerable, populations may be judged healthy simply because they show strong growth rates. Discounting the problem of inbreeding depression may be premature especially under novel circumstances such as environmental change or disease.
Finally, two mechanisms proposed to avoid or delay the costs of inbreeding depression and loss of genetic variation do not appear to be important in saddlebacks or robins. Heterozygosity was not related to survivorship in saddlebacks that successfully founded new populations, and neither saddlebacks nor robins chose genetically dissimilar mates to avoid inbreeding.
In conclusion, most saddleback populations should not require genetic management, although populations on small islands will probably need occasional immigrants. In robins, large, unfragmented populations should be protected where possible.
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Wilkin-Slaney, Katherine. "Becoming - Pakeha questioning the use of native birds in representation as a means of exploring New Zealand post-settler identity in visual art : an exegesis submitted to Auckland University of Technology for the degree of Master of Art and Design, 2008 /". Click here to access this resource online, 2008. http://hdl.handle.net/10292/723.
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The depiction of birds by artists such as Don Binney, Bill Hammond, Michael Parekowhai and Grant Whibley has served as metaphors in the conceptual systems of post-settler New Zealanders’ expression of identity. This project investigated unease in New Zealand post-settler identity and its dislocation from the past by considering works depicting native birds. Is depicting native - rather than introduced birds, an incongruous and romantic settler iconography in identity, leading to a re-telling of our place in this land at the expense of not only the rightful indigenous place of Maori, but of our own cultural becoming? By exploring the painting of birds as metaphors of New Zealand post-settler identity, the project aimed to contribute to the complex issues surrounding the entwined and entangled post-settler relationships of both the past and present. This painting project investigated these issues through the medium of oil paint, culminating in a body of artwork presented in an exhibition with an accompanying exegesis representing 20% of the work.
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Michel, Pascale, i n/a. "Habitat selection in translocated bird populations : the case study of Stewart Island robin and South Island saddleback in New Zealand". University of Otago. Department of Zoology, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070118.143501.
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The choice of a place to live and reproduce is crucial for species� survival in providing them with adequate resources and shelter from predators or climatic conditions. Determining habitat suitability in endangered species is important for the success of translocation as a conservation tool. In addition, understanding mechanisms (source/sink system versus ecological traps) that drive habitat selection in translocated animals may be critical to population viability. In New Zealand, where ecosystems are highly vulnerable to extinction, habitat restoration on predator-free off-shore islands is an important recovery tool. Therefore, there is a need to understand the relationship between the establishment of the translocated populations and the characteristics of their new environment.
Previous research indicated that re-introduced populations of Stewart Island robin (Petroica australis rakiura - Toutouwai) and South Island saddleback (Philesternus carunculatus carunculatus - Tieke) on Ulva Island (Stewart Island), New Zealand, showed preferences for coastal habitats that were characterized by low-lying dense vegetation and open ground cover. In this study, we further investigated territorial establishment in these two populations since re-introduction and looked at how birds utilised the landscape. I hypothesised that sites colonised soon after re-introduction were of high quality and later on, birds moved into unsuitable habitats. I defined habitat quality at a micro-scale in terms of vegetation structure, nest characteristics and food availability. I modeled bird presence and nesting success in relation to habitat components to determine factors in the environment that influenced breeding site selection and contributed to successful nesting in these two species. I discussed results in comparison to similar bird-habitat models developed for the South Island saddleback population on Motuara Island (Marlborough Sounds) and examined explanatory variables in each model.
Translocated birds in the three studied populations first established territories in coastal scrub, and in the following years moved into larger coastal forest stands. Although vegetation structure was the primary variable explaining site selection in these populations, vegetation composition should still be considered important as it dictated the suitability of nesting substrate and the availability of food items. There was no evidence that first-colonised areas were more suitable habitats, and I concluded that these cases could not be used as examples of ecological traps. Instead, results suggested that with increased density robins and saddlebacks on Ulva have more recently settled in sites less suitable to nesting and foraging, thus underlying a source/sink structure. However, the sparse distribution of food items on Motuara contributed to a lack of territorial behavior and environmental effect on breeding success; therefore a source/sink system could not be confirmed in this population. I recommended that future translocation sites give preference to mixed-size stands with broadleaved species that are characterised by dense canopy below 4 m height and with suitable cavities in live trees. Lastly, due to robins� and saddlebacks� attraction to conspecifics and their territorial behavior, resources evenly distributed across the landscape could also increase their survival and reproductive success.
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Impson, F. A. C. "Biological control of Acacia cyclops in South Africa : the role of an introduced seed-feeding weevil, Melanterius servulus (Coleoptera: Curculionidae), together with indigenous seed-sucking bugs and birds". Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/6272.
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Includes bibliographical references (leaves 78-94).Acacia cyclops A. Cunn ex G. Don, or rooikrans (Fabaceae), of Australian origin, is an invasive environmental weed in South Africa where it threatens the unique vegetation of the Cape Floral Kingdom. The invasiveness of the plant in South Africa is, in part, due to its high annual seed-yields, together with the suitable climatic and edaphic factors found here. This study investigated the role of a seed-feeding weevil, Melanterius servulus, which was first introduced into South Africa during 1991, as a biological control agent of A. cyclops seeds, together with the combined effects of indigenous seed-sucking bugs and birds. The weevils utilise filled green pods of A. cyclops for adult feeding, oviposition and larval development and completely destroy seeds during these activities. Examination of the reproductive phenology of A. cyclops showed that seeds are produced annually, during summer and that the presence of filled green pods on the plants coincides with the period of reproductive activity of the weevils. Melanterius servulus populations have established readily at all the original release sites, and within four years of release, damage levels to seeds commonly reached 90%. The weevils have dispersed at an average rate of approximately 2 km per year. Since becoming established in South Africa. the seeds of A. cyclops have been utilised by a variety of generalist vertebrate and invertebrate organisms. Indigenous polyphagous alydid bugs feed on the mature seeds, rendering a portion of the crop inviable when damage levels are high (more than five feeding-punctures per seed). Several bird species are attracted to and feed on the fleshy aril that surrounds theseeds of A. cyclops. Passage of the seeds through the gut of birds enhances germination rates. There is a synergetic relationship between alydids and birds because seeds with low levels of alydid feeding (one to four punctures per seed) germinated more readily after passage through birds than seeds that were not eaten by birds.
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MacFarlane, Archie. "Frugivorous mutualisms in a native New Zealand forest : the good the bad and the ugly". Thesis, University of Canterbury. Biological Sciences, 2012. http://hdl.handle.net/10092/7636.
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Widespread anthropogenic invasions have prompted concerns that naturalized organisms could threaten biodiversity. In particular, invasive weeds can negatively affect native biota through a variety of means, including disrupting mutualisms. This thesis was designed to observe and test dispersal mutualisms in a native forest during autumn when the majority of plant species are fruiting.
In this thesis I examined whether the invasive plant barberry (Berberis glaucocarpa) was influencing the behaviour of a native frugivore bellbird (Anthornis melanura) and a range of dispersal related services in a native forest, Kowhai Bush near Kaikoura. To test these 18 banded bellbirds were followed through autumn 2011. These observe bellbirds were split between control and test bird. Barberry fruit was removed from the test bird territories. I recorded whether bellbirds changed their territory sizes, foraging and daily behaviours. During 52 hours of observations, bellbirds were never observed feeding on barberry fruit. No significant changes to bellbird behaviour or territories were observed after the removal of barberry fruit. Bellbird diet overall was dominated by invertebrates (83% of foraging observations), with smaller contributions from fruit (16%, nearly all on Coprosma robusta), nectar and honeydew. Since bellbirds did not eat barberry fruit, removal of this weed is unlikely to negatively affect bellbirds during autumn.
Which other bird species were dispersing barberry was recorded. I recorded 242 hours of videotape footage on 24 fruiting plants. A total of 101 foraging events were recorded of 4 different bird species: silvereyes (Zosterops lateralis) 42 visits, blackbirds (Turdus merula) 27 visits, song thrush (Turdus philomelos) 29, and starlings (Sturnus vulgaris) 3 visits. The species differed in the mean length of time they spent in plants, so the overall contribution to barberry fruit removal was 32.6% silvereyes, 24.3% blackbirds, 42.9% song thrush and 0.1% starlings.
To find out the relative contribution of exotic and native birds to dispersal of fruits in Kowhai Bush, I mist-netted 221 birds of 10 species and identified any seeds in the 183 faeces they deposited. A total of 21 plant species were observed fruiting in Kowhai Bush during this time. A total of 11 different plant species were identified from 1092 seeds. Birds were further observed feeding on 3 other plant species which were not observed in faecal samples. This left 7 plants with unobserved dispersal vectors. There were likely four main dispersers, bellbirds, silvereyes, song thrush and blackbirds and five minor, brown creeper (Mohoua novaeseelandiae), tui (Prosthemadera novaeseelandiae), fantails (Rhipidura fuliginosa), dunnock (Prunella modularis) and starlings. However there was considerable variability between these bird species dispersal abilities. Introduced birds’ song thrush and blackbirds were observed dispersing naturalized plant seeds at higher than expected rates in comparison to native frugivores bellbirds and silvereyes. I also measured the gape sizes on mist netted birds and on samples of fruit from Kowhai Bush. Both silvereyes and bellbirds were found to be eating fruit larger than their gape, but despite this two native (Hedycarya arborea and Ripogonum scandens) and three exotic plants (Vitis vinifera, Taxus baccata and Crataegus monogyna) had large fruit that were probably mainly dispersed by song thrush and blackbirds. Hence, introduced birds were important seed dispersers for large fleshy fruited seeds in Kowhai Bush. Demonstrating that interactions among native and exotic flesh fruited plants and frugivores is important within forest communities.
Książki na temat "Introduced birds"
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L, Lockwood Julie, i Cassey Phillip, red. Avian invasions: The ecology and evolution of exotic birds. Oxford: Oxford University Press, 2009.
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Nankinov, Dimitŭr Nikolov. Chuzhdite vidove ptit︠s︡i v Evropa. Sofii︠a︡: [s.n.], 2006.
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Andreotti, A. Mammiferi e uccelli esotici in Italia: Analisi del fenomeno, impatto sulla biodiversità, e linee guida gestionali. Italy]: Ministero dell'ambiente, Servizio conservazione natura, 2001.
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Robert, Gillmor, red. Naturalized birds of the world. Harlow, Essex, England: Longman Scientific & Technical, 1987.
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New Zealand. Department of Conservation, red. New Zealand's introduced birds of town and country. Auckland, N.Z: Penguin Books in association with Dept. of Conservation, 1997.
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Xiao xin yi yi: Qian zai wei xie Taiwan de wai lai niao lei tu jian. Nantou Xian: Xing zheng yuan nong ye wei yuan hui te you sheng wu yan jiu bao yu zhong xin, 2011.
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1951-, Barnett Stephen, red. The Penguin guide to New Zealand wildlife: Native and introduced birds, mammals, reptiles, and amphibians. Auckland, N.Z: Penguin Books, 2002.
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Spilsbury, Richard. Invasive species in the air. New York: PowerKids Press, 2015.
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Kanasaka, Kiyonori. Isabella Bird and Japan. Tłumacz Nicholas Pertwee. GB Folkestone: Amsterdam University Press, 2017. http://dx.doi.org/10.5117/9781898823513.
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This book places Bird's visit to Japan in the context of her worldwide life of travel and gives an introduction to the woman herself. Supported by detailed maps, it also offers a highly illuminating view of Japan and its people in the early years of the 'New Japan' following the Meiji Restoration of 1868, as well as providing a valuable new critique on what is often considered as Bird's most important work. The central focus of the book is a detailed exploration of Bird's journeys and the careful planning that went into them with the support of the British Minister, Sir Harry Parkes, seen as the prime mover, who facilitated her extensive travels through his negotiations with the Japanese authorities. Furthermore, the author dismisses the widely-held notion that Bird ventured into the field on her own, revealing instead the crucial part played by Ito, her young servant-interpreter, without whose constant presence she would have achieved nothing. Written by Japan's leading scholar on Isabella Bird, the book also addresses the vexed question of the hitherto universally-held view that her travels in Japan in 1878 only involved the northern part of Honshu and Hokkaido. This mistaken impression, the author argues, derives from the fact that the abridged editions of Unbeaten Tracks in Japan that appeared after the 1880 two-volume original work entirely omit her visit to the Kansai, which took in Osaka, Kyoto, Kobe and the Ise Shrines. Bird herself tells us that she wrote her book in the form of letters to her sister Henrietta but here the author proposes the intriguing theory that these letters were never actually sent. Many well-known figures, Japanese and foreign, are introduced as having influenced Bird's journey indirectly, and this forms a fascinating sub-text.
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Cassey, Phillip, Tim M. Blackburn i Julie L. Lockwood. Avian Invasions: The Ecology and Evolution of Exotic Birds. Oxford University Press, 2009.
Znajdź pełny tekst źródłaCzęści książek na temat "Introduced birds"
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Nummi, Petri. "Introduced Semiaquatic Birds and Mammals in Europe". W Invasive Aquatic Species of Europe. Distribution, Impacts and Management, 162–72. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-015-9956-6_18.
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Callaghan, Corey T., i Daniel M. Brooks. "Using citizen science to study exotic and invasive birds." W Invasive birds: global trends and impacts, 363–68. Wallingford: CABI, 2020. http://dx.doi.org/10.1079/9781789242065.0363.
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Abstract This chapter describes the current usage of citizen science to increase the current knowledge of exotic and invasive bird populations. Citizen science projects aimed at studying and tracking exotic birds are divided into two categories: those that are part of a broad-scale biodiversity collection scheme, and those that are species focused. Some of the current literature that integrates citizen science data and the effects, management and implications of introduced birds are summarized, and select examples that highlight the potential of citizen science aimed at gathering various types of information about exotic birds are included. A vision for the future of citizen science aimed at studying exotic birds is also discussed.
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Debussche, M., i P. Isenmann. "Introduced and cultivated fleshy-fruited plants: consequences of a mutualistic Mediterranean plant-bird system". W Biological Invasions in Europe and the Mediterranean Basin, 399–416. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-1876-4_26.
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Wang, Liang, i Jianxin Zhao. "Distributed Computing". W Architecture of Advanced Numerical Analysis Systems, 243–79. Berkeley, CA: Apress, 2022. http://dx.doi.org/10.1007/978-1-4842-8853-5_10.
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AbstractDistributed computing has been playing a significant role in current smart applications in various fields. In this chapter, we first briefly give a bird’s-eye view of this topic, introducing various programming paradigms. Next, we introduce Actor, an OCaml-based distributed computing engine, and how it works together with Owl. We then focus on one key element in distributed computing: the synchronization. We introduce four different types of synchronization methods or “barriers” that are commonly used in current systems. Next, we elaborate how these barriers are designed and provide illustrations from the theoretical perspective. Finally, we use evaluations to show the performance trade-offs in using different barriers.
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Fukui, Hideo. "Real Estate and the Legal System of Japan". W New Frontiers in Regional Science: Asian Perspectives, 3–7. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8848-8_1.
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AbstractIn Part I, entitled Real Estate and the Legal System, we analyze owner-unknown land issues, land acquisitions, and real estate auctions.The use and value of real estate such as land and buildings are significantly affected by public laws and regulations related to urban planning and construction, the environment, and taxation; for example, contract laws such as the Act on Land and Building Leases; private laws regulating torts, collateral enforcement, and so on; tax laws that regulate transfer taxes, ownership taxes, and transaction taxes; and regulations surrounding land use and urban infrastructure development. This paper discusses, therefore, the relationships between these laws and real estate, identifies problems in the laws associated with real estate in Japan, and proposes improvements.First, in recent years, owner-unknown land issues have become a serious concern in Japan. The Japanese registry does not always reflect the actual rightful owner, primarily because such registration is only a perfection requirement in civil law and registration involves a great deal of time and money. For example, because a large extent of land is registered to owners from nearly 100 years ago, it has changed hands many times through inheritance, which means that today, it is extremely difficult to determine the actual owner (inheritor) without spending a great deal of time and money. However, if the profits to be obtained from the land do not justify such expense, the land remains unused as “owner-unknown land.”Buying and selling land under Japanese civil law requires an agreement from all landowners including in the case of shared ownerships; therefore, even if the land has high returns, if it is “owner-unknown land,” it cannot be used effectively. With a focus on unknown-owner land, in this section, four writers provide multifaceted perspectives on the causes thereof, the defects in the current system, and the possible solutions.Eminent domain, the system which allows the acquisition of land against the land owner’s will for public projects, is widely institutionalized in many countries. It works to mitigate the owner-unknown land issues as far as lands are acquired by public projects.Further, real estate auctions are often held when liens are placed on land and/or residences for housing loan defaults. The Japanese civil auction system, which was institutionalized at the end of the nineteenth century, stipulates that a tenancy that is behind on a mortgage may resist a purchase unconditionally as long as the mortgage default period is within 3 years (short-term lease protection system/former Civil Code Article 395). This system was intended to avoid the unstable use of mortgaged properties and to promote the effective use of real estate; however, because the majority of users and the beneficiaries of this system were in fact anti-social groups, it was used to demand money unjustly from debtors and buyers, thus preventing the effective use of the mortgaged properties.When the protection of short-term leases was abolished in 2004, these types of interferences are said to have decreased drastically. However, successful bids for auctioned real estate properties continue to be lower than in general transactions. Therefore, here, we provide a quantitative analysis of these situations and propose further auction system improvements.Below, we introduce the outlines of each theory in Part I.
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"Introduced Birds". W The Birds of Kaua'i, 60–90. University of Hawaii Press, 1999. http://dx.doi.org/10.1515/9780824844400-007.
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"Introduced Fowl". W Field Guide to the Birds of the Dominican Republic and Haiti, 52–53. Princeton University Press, 2022. http://dx.doi.org/10.1515/9780691233772-022.
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"Introduced Fowl". W Field Guide to the Birds of the Dominican Republic and Haiti, 52–53. Princeton University Press, 2022. http://dx.doi.org/10.2307/j.ctv2382dqx.24.
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Scott, Graham. "Evolution of birds". W Essential Ornithology, 1–20. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198804741.003.0001.
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This chapter explores the evolutionary history of birds. It considers the dinosaur origins of birds and the evolution of the modern bird lineages. The development of the modern bird from its prehistoric, reptilian ancestors is analysed by discussion of important fossil specimens, particularly that of Archaeopteryx, and the development of both morphological and biomolecular phylogenies. Evolution by natural selection is explained, as are processes of evolutionary adaptation and speciation. The conservation implications of hybridization are considered and the classification and nomenclature of birds is introduced. Throughout the chapter examples of current research are presented alongside established classic studies to engage the reader and provide a route into the relevant scientific literature.
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Long, J. L., i P. R. Mawson. "Species of introduced birds in mediterranean Australia". W Biogeography of Mediterranean Invasions, 365–76. Cambridge University Press, 1991. http://dx.doi.org/10.1017/cbo9780511525544.028.
Pełny tekst źródłaStreszczenia konferencji na temat "Introduced birds"
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Zhang, Xiaoqing, Weijing Zhang i Jun Chen. "Experimental Study on Hydrodynamic Characteristics of Hydrofoil of the Birds Embedded in Marine Seismic Streamers". W ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-20199.
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A “bird” is a device usually being used to control the depth and position of marine seismic streamers. Exact position of the streamers can effectively promote the precision, reduce the measured times and save the costs for marine seismic exploitation. So the “birds” have important significance to marine oil exploitation. A Hydrodynamic characters test concerning a new embedded bird has been introduced in this paper. And some useful hydrodynamic character-data of the hydrofoil are obtained, such as lift-attack angle diagram, resistance-attack angle diagram, torque-attack angle diagram. These data and diagrams are more helpful for studying on the embedded bird, including the control method and control strategy etc. Above all, the results of the test have significant reference value for the control of birds and marine seismic streamers.
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Grindheim, Jan Vidar, Inge Revhaug, Ken Welker, Peder Solheim i Egil Pedersen. "Validation of Seismic Streamer Simulator and Sea Current Estimator Using Full Scale Data". W ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77163.
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Survey optimization and cost reductions are ongoing challenges for the marine seismic petroleum exploration industry. The present research intends to improve seismic streamer steering as well as to reduce time on line-changes, where the streamer spread is turned 180 degrees. Sea current estimation and prediction of future streamer state are important aspects of improved streamer steering, which will increase survey efficiency and quality. A seismic streamer simulator has been validated against full scale proprietary data from two seismic survey line-changes. The streamer spread has 12 cables of slightly more than 4 km length each, with 13 control birds for each streamer. Interpolated Acoustic Doppler Current Profiler (ADCP) measured sea current is introduced at the streamer nodes. Two streamer tension cells are installed at each streamer, giving validation of simulated tension. Secondly, a sea current estimation algorithm has been validated against the interpolated ADCP current data for the two line-changes.
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Shafer, Michael W., Robert MacCurdy i Ephrahim Garcia. "Testing of Vibrational Energy Harvesting on Flying Birds". W ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/smasis2013-3063.
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Discrete animal-mounted sensors and tags have a wide range of potential applications for researching wild animals and their environments. The devices could be used to monitor location, metabolic output, or used as environmental monitoring sentinels. These applications are made possible by recent decreases in the size, mass, and power consumption of modern microelectronics. Despite these performance increases, for extended deployments these systems need to generate power in-situ. In this work, we explore a device that was recently deployed to test the concept of vibrational piezoelectric energy harvesting on flying birds. We explain the development of the device and introduce test results conducted on flying pigeons (Columba livia). The 12 g testing device consisted of a miniature data acquisition system and a piezoelectric energy harvester. The system recorded both the harvested power and the in-flight accelerations of the bird. The energy harvester included a wireless receiver, battery and linear servo. By remotely actuating the linear servo, we were able to arrest the energy harvester for portions of the flight. In doing so, we will be able to compare flight accelerations of a bird with a simple proof mass and with a dynamic mass without having to stop the flight of the bird. The comparison of these two cases allows for the assessment of the feasibility of employing vibrational energy harvesting on a flying bird. We present the initial results of this testing with regard to the harvested power and the in-flight acceleration profiles.
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Blower, Christopher J., i Adam M. Wickenheiser. "The Validation of a Generalized Aerodynamic Model for a Multi-Body Bio-Inspired Wing". W ASME 2013 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/smasis2013-3075.
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Bio-inspiration has introduced new and innovative flow control methods in gust alleviation, maneuverability and stability improvement for morphing aircraft wings. The bio-inspired wing model under consideration imitates the techniques used by birds to manipulate localized air flow through the installation of feather-like panels across the airfoil’s upper and lower surface, replacing the traditional wing’s surface and trailing edge flap. Each flap is designed to rotate into both the airfoil profile and inbound air flow, using a single degree of freedom about their individual hinge points located at 20%, 40%, 60% and 80% of the chord. This wing morphing technique offers flap configurations typically unattainable by traditional aircraft and enables some advantageous maneuvers, including reduced turning radii and aero-braking. Due to the number of potential configurations, a generalized adaptive panel method (APM) has been developed to model the pressure distribution using a series of constant-strength doublets along the airfoil surface. To accommodate for the wake regions generated by the unconventional wing profiles, viscous Computational Fluid Dynamics (CFD) simulations are performed to characterize these regions and identify their outer boundaries. The wake profile geometries are integrated into the APM, and are used to accurately model the aerodynamic influence of the wake. To calculate the drag generated by each configuration, Thwaites’ laminar and Head’s turbulent boundary layer methods are implemented to enable identification of flow transition and separation along the airfoil surface. The integration of these aerodynamic techniques allows the flight characteristics, including the pressure, friction, lift, drag, and moment coefficients, of each morphing airfoil configuration to be calculated. The computed aerodynamic coefficients are validated using experimental data from a 4′×1′×1′ test section in a low speed suction wind tunnel operating over a Reynolds Number range of 150,000–450,000.
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Terao, Yutaka, i Shunji Sunahara. "Application of a Wave Devouring Propulsion System to Ocean Engineering". W ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83122.
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A WDPS (wave devouring propulsion system) is a device that generates thrust directly from wave power and, at the same time, generates large damping forces. This phenomena is same as the thrust generation by the oscillating hydrofoil which are commonly used as the animal propulsion system such as the sea mammals or birds or fish propulsion. Relative flow acting on the hydrofoil generates thrust and damping force respectively. It is quite simple and consists of hydrofoils positioned in front of the bow. If the WDPS is installed in a ship hull, it can drive the hull (even against waves). One example is shown in Photo 1-1, the small WDPS vessel named Mermaid II, which succeeded in a historical trans-Pacific voyage from Hawaii to Japan (about 7800 km) in 2008 using only wave power. It proves that the WDPS may have some potential in the field of ocean engineering. In this paper we will propose two WDPS applications. One potential application is a midsized floating-type ocean wind turbine generator, which is composed of a single wind turbine on a catamaran hull with a set one-point mooring system. For this application, a new hull form and WDPS are developed based on Mermaid II. The hull needs to be stabilized because the ocean wind energy absorption efficiency is affected by the hull’s motion. Additionally, the mooring forces acting on the hull need to be reduced to keep the construction and power generation costs down. Therefore, the WDPS is installed in front of the hull to reduce/overcome the wave drifting force and the wind drag force. Another anticipated function of the WDPS is motion stabilization, particularly for pitch and roll motions. A suitable hull form is determined from wave tank experiments and is discussed herein. The other proposal is a multi-function WDPS that functions as both a wave energy absorption device and a wave thruster. Many hydrofoil-type wave energy conversion systems with forward propulsion have been proposed, but no advanced speed-type systems with a multi-function WDPS. A newly designed forced heave-pitch oscillator is also introduced, and tests are performed in the wave tank. The optimum hydrofoil control method in waves is discussed, and the thrust control is also tested and discussed.
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Behkam, Bahareh, Amrinder S. Nain, Cristina H. Amon i Metin Sitti. "Design and Numerical Modeling of an On-Board Chemical Release Module for Motion Control of Bacteria-Propelled Swimming Micro-Robots". W ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68032.
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On/off motion control of bacteria-propelled synthetic bodies was previously achieved using a chemical switching technique. A chemical agent (CuSO4) directly binds to the rotor of the flagellar motor inhibiting it. When desired, a second chemical agent (EDTA) is introduced, which binds to the CuSO4 molecules, freeing the motor and allowing the bacteria to resume its motion [1]. To facilitate localized delivery of the control agents and reduce the diffusion time, we propose an on-board chemical release scheme for the first time. The proposed microfluidic motion control module contains two sets of optomechanically responsive nanocomposite paraffin wax micro-valves which can be independently actuated. To demonstrate the feasibility of the concept, a transient two-dimensional mass transfer numerical model is developed and the transient concentration profiles of the diffused chemicals at different locations on the robot body is studied. The results of this work provide crucial information required to determine the number, size, and location of the required micro-valves.
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Hasnain, Zohaib, James E. Hubbard, Joseph Calogero, Mary I. Frecker i Aimy A. Wissa. "Understanding the Relationship Between Pitch Agility and Propulsive Aerodynamic Forces in Bio-Inspired Flapping Wing Vehicles". W ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/smasis2015-8835.
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Ornithopters, or flapping wing mechanical birds, represent a unique category of aerial vehicles that fill a need for small-scale, agile, long range, and payload-capable flight vehicles. This study focuses on understanding the relationship between the propulsive aerodynamic forces and pitch agility in these flapping wing vehicles. Using analytical methods, the aerodynamic moment acting upon a wing undergoing elastic flapping was calculated. A method to determine the pitch stiffness of the vehicle was then derived using a preexisting stability analysis. This method was used to demonstrate that pitch agility in flapping wing birds is intricately tied to the flapping cycle with different parts of the cycle creating stabilizing and destabilizing effects. The results indicated that pitch agility, and propulsive force generation, have a dependency on the shape of the wing, and that deformations such as bend and sweep are capable of making the vehicle more agile. Contact-aided compliant mechanisms with nonlinear stiffness were designed and inserted into the wing of an ornithopter to induce controlled morphing. These elements have varying stiffness during the upstroke and downstroke parts of the cycle which introduces an asymmetry between the two halves of the flapping cycle. The resulting flapping motion exhibited a two fold increase in horizontal propulsive force over the baseline case. A motion tracking system was used to capture the free flight response of the ornithopter in steady level flight. This information was then used to calculate the pitch stiffness of the ornithopter with a rigid spar, and, one with a nonlinear compliant element inserted into the spar to induce a desired shape change. The results revealed that an upstroke in which the aerodynamic forces are similar in magnitude to that of the downstroke, may be necessary to make the vehicle more agile, and, that there is a compromise between vehicle agility and flight propulsive forces.
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Liu, Rui, Huilin Peng, Yong Chen i Dell Zhang. "HyperNews: Simultaneous News Recommendation and Active-Time Prediction via a Double-Task Deep Neural Network". W Twenty-Ninth International Joint Conference on Artificial Intelligence and Seventeenth Pacific Rim International Conference on Artificial Intelligence {IJCAI-PRICAI-20}. California: International Joint Conferences on Artificial Intelligence Organization, 2020. http://dx.doi.org/10.24963/ijcai.2020/482.
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Personalized news recommendation can help users stay on top of the current affairs without being overwhelmed by the endless torrents of online news. However, the freshness or timeliness of news has been largely ignored by current news recommendation systems. In this paper, we propose a novel approach dubbed HyperNews which explicitly models the effect of timeliness on news recommendation. Furthermore, we introduce an auxiliary task of predicting the so-called "active-time" that users spend on each news article. Our key finding is that it is beneficial to address the problem of news recommendation together with the related problem of active-time prediction in a multi-task learning framework. Specifically, we train a double-task deep neural network (with a built-in timeliness module) to carry out news recommendation and active-time prediction simultaneously. To the best of our knowledge, such a "kill-two-birds-with-one-stone" solution has seldom been tried in the field of news recommendation before. Our extensive experiments on real-life news datasets have not only confirmed the mutual reinforcement of news recommendation and active-time prediction but also demonstrated significant performance improvements over state-of-the-art news recommendation techniques.
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Gokhale, Tejas. "Vision beyond Pixels: Visual Reasoning via Blocksworld Abstractions". W Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. California: International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/907.
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Deep neural networks trained in an end-to-end fashion have brought about exceptional advances in computer vision, especially in computational perception. We go beyond perception and seek to enable vision modules to reason about perceived visual entities such as scenes, objects and actions. We introduce a challenging visual reasoning task, Image-Based Event Sequencing (IES) and compile the first IES dataset, Blocksworld Image Reasoning Dataset (BIRD). Motivated by the blocksworld concept, we propose a modular approach supported by literature in cognitive psychology and children's development. We decompose the problem into two stages - visual perception and event sequencing, and show that our approach can be extended to natural images without re-training.
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Grindheim, Jan Vidar, Ken E. Welker i Inge Revhaug. "Application for Improved Awareness of Cable Geometry During Seismic Survey Operation". W ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-95038.
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Abstract Seismic surveys for petroleum exploration employ a number of towed cable streamers of lengths in the order of 3∼12 km. Accurate positioning is important both for navigation and control of the streamer spread and for seismic data processing. In the present study, a numerical streamer model based on a Finite Element Method is implemented both as an Extended Kalman filter and an Ensemble Kalman filter. The streamer model includes features such as tailbuoy, locally estimated sea current introduced at each node, control bird inputs, cable stretch and tension. The filter implementations are intended to blend the streamer model with observations such as acoustic range measurements and satellite navigation positioning. The implementations have been compared and validated employing full scale data for two line changes. The purpose is to investigate the filters’ performance during periods with poor or missing observations.
Raporty organizacyjne na temat "Introduced birds"
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Perk, Simon, Egbert Mundt, Alexander Panshin, Irit Davidson, Irina Shkoda, Ameera AlTori i Maricarmen Garcia. Characterization and Control Strategies of Low Pathogenic Avian Influenza Virus H9N2. United States Department of Agriculture, listopad 2012. http://dx.doi.org/10.32747/2012.7697117.bard.
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The avian influenza virus, subtype H9N2 subtype, defined as having a low pathogenicity, causes extensive economical losses in commercial flocks, probably due to management and synergism with other pathogens. AIV H9N2 was first identified in Israel in the year 2000, and since then it became endemic and widespread in Israel. Control by vaccination of commercial flocks with an inactivated vaccine has been introduced since 2007. In face of the continuous H9N2 outbreaks, and the application of the vaccination policy, we aimed in the present study to provide a method of differentiating naturally infected from vaccinated animals (DIVA). The aim of the assay would be detect only antibodies created by a de-novo infection, since the inactivated vaccine virus is not reproducing, and might provide a simple tool for mass detection of novel infections of commercial flocks. To fulfill the overall aim, the project was designed to include four operational objectives: 1. Evaluation of the genetic evolution of AIV in Israel; 2. Assessment of the diagnostic value of an NS1 ELISA; 3. NS1 ELISA as evaluation criteria for measuring the efficacy of vaccination against H9N2 AIV; 4. Development of an AIV H9 subtype specific ELISA systems. Major conclusion and implications drawn from the project were: 1. A continuous genetic change occurred in the collection of H9N2 isolates, and new introductions were identified. It was shown thatthe differences between the HA proteins of viruses used for vaccine productionand local fieldisolatesincreasedin parallelwith the durationand intensity ofvaccine use, therefore, developing a differential assay for the vaccine and the wild type viruses was the project main aim. 2. To assess the diagnostic value of an NS1 ELISA we first performed experimental infection trials using representative viruses of all introductions, and used the sera and recombinant NS1 antigens of the same viruses in homologous and heterologous NS1 ELISA combination. The NS1 ELISA was evidently reactive in all combinations, and did not discriminate significantly between different groups. 3. However, several major drawbacks of the NS1 ELISA were recognized: a) The evaluation of the vaccination effect in challenged birds, showed that the level of the NS1 antibodies dropped due to the vaccination-dependent virus level drop; b) the applicability of the NS1-ELISA was verified on sera of commercial flocks and found to be unusable due to physico-chemical composition of the sera and the recombinant antigen, c) commercial sera showed non-reactivity that might be caused by many factors, including vaccination, uncertainty regarding the infection time, and possibly low antigen avidity, d) NS1 elevated antibody levels for less than 2 months in SPF chicks. Due to the above mentioned reasons we do not recommend the application of the DIVA NS1 ELISA assay for monitoring and differentiation AIV H9N2 naturally-infected from vaccinated commercial birds.
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Balat, Jorge, Juan Esteban Carranza, Juan David Martin i Álvaro Riascos. El efecto de cambios en la regulación del mercado mayorista de electricidad en Colombia en un modelo estructural de subastas complejas. Banco de la República, październik 2022. http://dx.doi.org/10.32468/be.1211.
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We investigate the effects of a change in the regulation of the spot market for electricity in Colombia that took place in 2009. Specifically, the regulation switched from an auction mechanism with simple bids to one with complex bids to allow generators to separately bid on variable and quasi-fixed components. This greater flexibility was introduced to reduce production inefficiencies that arise from non-convexities in the cost structures of thermal generators. In this paper, we estimate and compute a structural model to quantify the effects of this change on allocation efficiency along with the effects on the wholesale price of electricity in Colombia. Consistently with previous reduced form evidence, we show that the production efficiency increased under the new dispatch mechanism, but prices increased.
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Marks, David R. Mute Swans. U.S. Department of Agriculture, Animal and Plant Health Inspection Service, luty 2018. http://dx.doi.org/10.32747/2018.7208745.ws.
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Mute swans (Cygnus olor) are an invasive species originally brought to the United States in the late 19th and early 20th centuries for ornamental ponds and lakes, zoos and aviculture collections. Original populations were located in northeastern states along the Hudson Valley but have since expanded to several Midwestern states and portions of the western U.S. and Canada. Mute swan damage includes competing with native waterfowl, destroying native plants, spreading disease, and colliding with aircraft. They are also considered a nuisance in some areas due to their abundant fecal droppings and aggressiveness towards people. Some have questioned the status of mute swans as an introduced species, but multiple reviews by scientists and the U.S. Fish and Wildlife Service clearly support the conclusion that mute swans are not native to North America. The Migratory Bird Treaty Act, therefore, does not protect mute swans, and management authority falls under jurisdiction of the states and Tribes.