11,361 research outputs found
The Yagita invariant of symplectic groups of large rank
Fix a prime , and let be any subring of the complex numbers that is
either integrally closed or contains a primitive th root of 1. For each
we compute the Yagita invariant at the prime for the symplectic
group .Comment: Minor changes compared to first versio
Identifying innovative and effective practice in e-assessment: findings from seventeen UK case studies
The aim of this JISC funded project was to extend the understanding of what e-assessment meant to users and producers in the HE and FE sectors. A case study methodology was employed to identify and report upon best and current practice within this field of inquiry. This approach facilitated the identification of both the enabling factors and barriers associated with e-assessment.
The variety of applications of e-assessment studied and their innovation and general effectiveness indicate the potential of e-assessment to significantly enhance the learning environment and the outcomes for students, in a wide range of disciplines and applications
The negative educational gradients in Romanian fertility
In Western countries, rates of second and third births typically increase with educational attainment, a feature that usually disappears if unobserved heterogeneity is brought into the event-history analysis. By contrast, in a country like Romania, second and third birth rates have been found to decline when moving across groups with increasing education, and the decline becomes greater if unobserved heterogeneity is added to the analysis. The present paper demonstrates this pattern, and shows that, because this feature is retained in the presence of control variables, such as age at first birth and period effects, the selectivity is not produced by a failure to account for the control variables.educational attainment, fertility, relative risks, Romania, unobserved heterogeneity
Economic system dynamics
We provide the reader with a qualitative summary of the main ideas from econophysics and finance theory, starting with a thorough criticism of the standard ideas taught in typical economics textbooks. The emphasis is on the Galilean or physicists' approach to market synamics, as opposed to the standard nonempirical postulatory one.Utility; equilibrium; supply and demand curves; business cycles; market dynamics
Individual variation in pup vocalizations and absence of behavioral signs of maternal vocal recognition in Weddell seals (Leptonychotes weddellii)
Individually stereotyped vocalizations often play an important role in relocation
of offspring in gregarious breeders. In phocids, mothers often alternate between foraging at sea and attending their pup. Pup calls are individually distinctive in various
phocid species. However, experimental evidence for maternal recognition is rare.
In this study, we recorded Weddell seal (Leptonychotes weddellii) pup vocalizations
at two whelping patches in Atka Bay, Antarctica, and explored individual vocal
variation based on eight vocal parameters. Overall, 58% of calls were correctly classified according to individual. For males (n = 12) and females (n = 9), respectively,
nine and seven individuals were correctly identified based on vocal parameters. To
investigate whether mothers respond differently to calls of familiar vs. unfamiliar
pups, we conducted playback experiments with 21 mothers. Maternal responses
did not differ between playbacks of own, familiar, and unfamiliar pup calls. We
suggest that Weddell seal pup calls may need to contain only a critical amount
of individually distinct information because mothers and pups use a combination
of sensory modalities for identification. However, it cannot be excluded that pup
developmental factors and differing environmental factors between colonies affect
pup acoustic behavior and the role of acoustic cues in the relocation process
Between-Year Survival and Rank Transitions in Male Black-Capped Chickadees (\u3cem\u3ePoecile Atricapillus\u3c/em\u3e): A Multistate Modeling Approach
In dominance-structured animal societies, variation in individual fitness is often related to social status. Like many passerine birds, Black-capped Chickadees (Poecile atricapillus) have a short average adult life-expectancy (Ø2 years); however, the maximum recorded life span is \u3e5× as long. Enhanced annual survival could contribute to greater lifetime reproductive success for male Black-capped Chickadees with high social rank. We used multistate capture–mark–recapture models to estimate annual survival of male Black-capped Chickadees in Ontario using resighting and recapture data collected from 1997 to 2002. Our goal was to evaluate support for an influence of rank on annual survival and estimate its effect size for a food-supplemented study site. We also statistically modeled the probability of between-year rank transitions. Model selection based on Akaike’s information criterion provided support for an effect of rank on survival. However, multimodel inference revealed that the size of the effect was rather small. Over the six study years, model-averaged estimates of the survival benefit of high versus low rank ranged from 5.0 to 7.3%. As expected, survival was strongly year-dependent, with model-averaged estimates of annual survival probability varying between 0.36 and 0.73. Age was an important predictor of the probability of rank transitions. Low-ranked second-year birds were less likely than older low-ranked birds to advance to high rank between years; likewise, high-ranked after-second-year birds were less likely to drop in rank. Other studies have found larger effects of rank on survival than we observed here. Future research should consider how interactions between social and environmental factors influence annual survival
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