Significant experimental, computational, and theoretical work has identified rich structure within the coordinated activity of interconnected neural populations. An emerging challenge now is to ...uncover the nature of the associated computations, how they are implemented, and what role they play in driving behavior. We term this computation through neural population dynamics. If successful, this framework will reveal general motifs of neural population activity and quantitatively describe how neural population dynamics implement computations necessary for driving goal-directed behavior. Here, we start with a mathematical primer on dynamical systems theory and analytical tools necessary to apply this perspective to experimental data. Next, we highlight some recent discoveries resulting from successful application of dynamical systems. We focus on studies spanning motor control, timing, decision-making, and working memory. Finally, we briefly discuss promising recent lines of investigation and future directions for the computation through neural population dynamics framework.
The unprecedented rate of extinction calls for efficient use of genetics to help conserve biodiversity. Several recent genomic and simulation-based studies have argued that the field of conservation ...biology has placed too much focus on conserving genome-wide genetic variation, and that the field should instead focus on managing the subset of functional genetic variation that is thought to affect fitness. Here, we critically evaluate the feasibility and likely benefits of this approach in conservation. We find that population genetics theory and empirical results show that conserving genome-wide genetic variation is generally the best approach to prevent inbreeding depression and loss of adaptive potential from driving populations toward extinction. Focusing conservation efforts on presumably functional genetic variation will only be feasible occasionally, often misleading, and counterproductive when prioritized over genome-wide genetic variation. Given the increasing rate of habitat loss and other environmental changes, failure to recognize the detrimental effects of lost genome-wide genetic variation on long-term population viability will only worsen the biodiversity crisis.
ABSTRACT In this work, the population dynamics and reproductive aspects of two sympatric Hyalella species in a river spring were analyzed in the northwestern state of Rio Grande do Sul, Brazil. The ...samplings were performed by one person, for ten minutes and using a hand net for one-year period (March 2018 to April 2019) and transported to the laboratory. All individuals sampled were sexed, measured, and separated by cephalothorax length (CC) size classes. Hyalella gauchensis Streck & Castiglioni, 2017 was 22.7 times more frequent and showed significantly greater mean cephalothorax when compared to Hyalella longipropodus Limberger, Graichen & Castiglioni, 2021. Males had a larger body size (CC) than females, although they occur in smaller numbers in both species. The total frequency distribution in CC size classes was bimodal in males and juveniles, and polimodal in females of H. gauchensis. In H. longipropodus the distribution as bimodal in males, females and juveniles. Both H. gauchensis and H. longipropodus had their breeding season and recruitment during the colder seasons of the year (fall and winter, respectively). However, there was a seasonal temporal separation of the intensity peaks between the two species, which could indicate different strategies and/or evolutionary adaptations for their coexistence.
RESUMO Neste trabalho foram analisadas a biologia populacional e aspectos reprodutivos de duas espécies simpátricas de Hyalella em uma nascente encontrada na região noroeste do estado do Rio Grande do Sul, Brasil. As amostragens foram realizadas por uma pessoa durante dez minutos com puçá no período de um ano (Março/2018 a Abril/2019) e transportadas ao laboratório. Todos os indivíduos amostrados foram sexados, mensurados e separados por classes de tamanho de comprimento do cefalotórax (CC). Hyalella gauchensis Streck & Castiglioni, 2017 foi 22,7 vezes mais frequente e apresentou comprimento do cefalotórax médio significativamente superior a Hyalella longipropodus Limberger, Graichen & Castiglioni, 2021. Machos apresentaram maior tamanho corpóreo (CC) que as fêmeas, embora ocorram em menor número em ambas as espécies. A distribuição de frequência total em classes de tamanho de CC foi bimodal em machos e juvenis e polimodal em fêmeas de H. gauchensis. Em H. longipropodus a distribuição foi bimodal em machos, fêmeas e juvenis. Tanto H. gauchensis quanto H. longipropodus tiveram seu pico reprodutivo e de recrutamento durante as estações mais frias do ano (outono e inverno, respectivamente), entretanto, houve separação temporal sazonal dos picos de intensidade entre as duas espécies, o que poderia indicar diferentes estratégias e/ou adaptações evolutivas para a coexistência das mesmas.
The Coronavirus Disease 2019 (COVID-19) pandemic has changed many social, economic, environmental and healthcare determinants of health. We applied an ensemble of 16 Bayesian models to vital ...statistics data to estimate the all-cause mortality effect of the pandemic for 21 industrialized countries. From mid-February through May 2020, 206,000 (95% credible interval, 178,100-231,000) more people died in these countries than would have had the pandemic not occurred. The number of excess deaths, excess deaths per 100,000 people and relative increase in deaths were similar between men and women in most countries. England and Wales and Spain experienced the largest effect: ~100 excess deaths per 100,000 people, equivalent to a 37% (30-44%) relative increase in England and Wales and 38% (31-45%) in Spain. Bulgaria, New Zealand, Slovakia, Australia, Czechia, Hungary, Poland, Norway, Denmark and Finland experienced mortality changes that ranged from possible small declines to increases of 5% or less in either sex. The heterogeneous mortality effects of the COVID-19 pandemic reflect differences in how well countries have managed the pandemic and the resilience and preparedness of the health and social care system.
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