6,813 research outputs found
A New 3D Potential-Density Basis Set
A set of bi-orthogonal potential-density basis functions is introduced to
model the density and its associated gravitational field of three dimensional
stellar systems. Radial components of our basis functions are weighted integral
forms of spherical Bessel functions. We discuss the properties of our basis
functions and demonstrate their shapes for the latitudinal Fourier number
.Comment: 2 pages. To appear in the proceedings of IAU Symposium 245,
"Formation and Evolution of Galaxy Bulges," M. Bureau, E. Athanassoula, and
B. Barbuy, ed
Socialism and the arts of use
https://stars.library.ucf.edu/prism/1223/thumbnail.jp
The Wild and the Tame
The Western belief that the world is divided into the human and the natural stems from the philosophy, first propounded by the ancient Greeks, notably Aristotle, that all living organisms could be placed in a Scale of Nature or Great Chain of Being with primeval slime at its base and Man at its summit. This belief, which is imbued in Christianity and in all aspects of western civilization, has led to a great divide with the wild on one side and the tame , that is all the animals and plants that are exploited by human, on the other
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Social evolution in mammals
Long-term, individual-based field studies, the application of genetic techniques and phylogenetic reconstructions have led to substantial advances in our understanding of the diversity and evolution of mammalian breeding systems and their consequences. They show how contrasts in ecology, life histories and phylogeny affect the distributions of breeding females and breeding males; how the distributions of both sexes affect the evolution of breeding systems and the composition and kinship structure of social groups; how contrasts in breeding systems and the social environment that individuals encounter affect the selection pressures operating on both sexes and the evolution of their behavior, physiology and morphology; and how these differences affect the demography and dynamics of populations and their responses to variation in density, climate and human impact.European Research Counci
Costs of mating competition limit male lifetime breeding success in polygynous mammals.
This is the accepted version of the paper. The final published version is available from the Royal Society at http://rspb.royalsocietypublishing.org/content/281/1786/20140418.abstract.Although differences in breeding lifespan are an important source of variation in male fitness, the factors affecting the breeding tenure of males have seldom been explored. Here, we use cross-species comparisons to investigate the correlates of breeding lifespan in male mammals. Our results show that male breeding lifespan depends on the extent of polygyny, which reflects the relative intensity of competition for access to females. Males have relatively short breeding tenure in species where individuals have the potential to monopolize mating with multiple females, and longer ones where individuals defend one female at a time. Male breeding tenure is also shorter in species in which females breed frequently than in those where females breed less frequently, suggesting that the costs of guarding females may contribute to limiting tenure length. As a consequence of these relationships, estimates of skew in male breeding success within seasons overestimate skew calculated across the lifetime and, in several polygynous species, variance in lifetime breeding success is not substantially higher in males than in females.The Leverhulme Trust, the Isaac Newton Trust, and the European Research Council provided the funding for this study
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The evolution of social monogamy in mammals.
The evolution of social monogamy has intrigued biologists for over a century. Here, we show that the ancestral condition for all mammalian groups is of solitary individuals and that social monogamy is derived almost exclusively from this social system. The evolution of social monogamy does not appear to have been associated with a high risk of male infanticide, and paternal care is a consequence rather than a cause of social monogamy. Social monogamy has evolved in nonhuman mammals where breeding females are intolerant of each other and female density is low, suggesting that it represents a mating strategy that has developed where males are unable to defend access to multiple females.The Leverhulme Trust, the Isaac Newton Trust, and the European Research Council provided the funding for this study.This version is the author accepted manuscript. The final published version can be found here: http://www.sciencemag.org/content/341/6145/526.ful
Maternal longevity and offspring sex in wild ungulates
In species with sexual size dimorphism, the offspring of the larger sex usually have greater energy requirements and may lead to greater fitness costs for parents. The effects of offspring sex on maternal longevity, however, have only been tested in humans. Human studies produced mixed results and considerable debate mainly owing to the difficulty of distinguishing the effects of sexual dimorphism from sociocultural factors. To advance this debate, we examined how the relative number of sons influenced maternal longevity in four species of free-living ungulates (Soay sheep Ovis aries ; bighorn sheep, Ovis canadensis ; red deer, Cervus elaphus ; mountain goat, Oreamnos americanus ), with high male-biased sexual size dimorphism but without complicating sociocultural variables. We found no evidence for a higher cumulative cost of sons than of daughters on maternal longevity. For a given number of offspring, most females with many sons in all four populations lived longer than females with few sons. The higher cost of sons over daughters on maternal lifespan reported by some human studies may be the exception rather than the rule in long-lived iteroparous species
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Kalahari vulture declines, through the eyes of meerkats<sup>§</sup>
Vulture populations are experiencing rapid declines across the globe. While the declines have been most precipitous in Asia, recent reports suggest African populations are likewise imminently threatened. As the factors underlying these general population trends are multifaceted and will vary in their relative intensity spatially, it is imperative that monitoring data across different vulture populations is assimilated if targeted conservation action is to prove most effective. In this study, we highlight a medium-term decline in the African White-backed Vulture population inhabiting the southern Kalahari, South Africa, using a long-term behavioural data set collected from a habituated population of meerkats . Meerkats emit an alarm call on sighting airborne vultures, which elicits a group-level response, such that the rates at which this behaviour is recorded in meerkats provides a high-resolution proxy for local vulture abundance. Although unconventional, this sampling method uncovered a steady decline over 17 years in White-backed Vulture numbers that mirrors the temporal decline recently documented in other southern African populations.
Tout autour du globe, les populations de vautours connaissent un dĂ©clin rapide. Alors que ce dĂ©clin sâest prĂ©cipitĂ© au sein des populations dâAsie, de rĂ©cents rapports suggĂšrent que les populations africaines sont au moins aussi menacĂ©es Ă court terme. Les facteurs qui influencent ces tendances dĂ©mographiques gĂ©nĂ©rales ont plusieurs facettes et varient de maniĂšre spatiale dans leur intensitĂ© relative. Par consĂ©quent, il est impĂ©ratif de collecter et regrouper des donnĂ©es de surveillance sur diffĂ©rentes populations pour mettre en place des stratĂ©gies de conservation efficaces et ciblĂ©es. Dans cette Ă©tude, je souligne le dĂ©clin Ă moyen terme dâune population de Vautour africain () vivant dans la partie sud du Kalahari, en Afrique du Sud, en utilisant un jeu de donnĂ©es comportementales de long terme, rĂ©coltĂ©es sur une population de suricates () habituĂ©s. Les suricates Ă©mettent une vocalisation dâalarme lorsquâils voient un vautour en vol, ce qui dĂ©clenche une rĂ©ponse anti-prĂ©dateur au sein du groupe. La frĂ©quence Ă laquelle ce comportement est observĂ© et relevĂ© chez les suricates reprĂ©sente un substitut fiable et de grande rĂ©solution pour attester de lâabondance locale de vautours. Bien que peu conventionnelle, cette mĂ©thode dâĂ©chantillonnage a mis en Ă©vidence une diminution constante du nombre de Vautours africains au cours de 17 derniĂšres annĂ©es, qui reflĂšte le dĂ©clin rĂ©cemment documentĂ© dans dâautres populations dâAfrique australe.This paper has relied on the longitudinal behavioural data of the Kalahari Meerkat Project, which is currently supported by the European Research Council (Research Grant no. 294494 to TCB since July 2012), the Mammal Research Institute at the University of Pretoria, and the University of Zurich. JBT is funded by a NERC Doctoral Training Program
Social complexity and kinship in animal societies
Studies of eusocial invertebrates regard complex societies as those where there is a clear division of labour and extensive cooperation between breeders and helpers. In contrast, studies of social mammals identify complex societies as those where differentiated social relationships influence access to resources and reproductive opportunities. We show here that, while traits associated with social complexity of the first kind occur in social mammals that live in groups composed of close relatives, traits associated with the complexity of social relationships occur where average kinship between female group members is low. These differences in the form of social complexity appear to be associated with variation in brain size and probably reflect contrasts in the extent of conflicts of interest between group members. Our results emphasise the limitations of any unitary concept of social complexity and show that variation in average kinship between group members has farâreaching consequences for animal societies.This project was funded by the European Research Commission (grant no. 294494âTHCB2011)
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