Cold, Northern Winters: The Importance of Temperature to Overwinter Mortality of Age-0 White Crappies

Survival during the first winter of life can influence the recruitment of many fishes. We used field sampling and laboratory experiments to explore the mechanisms underlying first winter growth and survival of white crappie Pomoxis annularis, which exhibits variable recruitment. We sampled age-0 white crappies from four Ohio reservoirs before winter to evaluate whether large individuals had a greater energy density (kJ/g) than small ones and whether mean energy density differed among reservoirs. Energy density increased with fish size in all reservoirs, suggesting that small fish could die earlier if energy stores become limiting during winter. Mean energy density varied among reservoirs as well, suggesting that prewinter energy reserves could influence recruitment variability across reservoirs through their effects on winter starvation. Our laboratory experiment evaluated how fish size (small or large), feeding level (starved or fed), and winter severity (mild or severe) interact to influence the growth and survival of age-0 white crappies. The two winter severity treatments represented two extremes for Ohio winters (i.e., mild and severe). We calculated daily individual growth rates for all fish, energy density for a subset of fish, and percent survival across treatments. Winter severity strongly influenced survival: only 47% of all white crappies survived the severe winter, whereas 97% survived the mild winter. In the severe winter, neither size nor feeding level influenced mortality. Bomb calorimetry revealed energy density to be similar among fish that died and those that survived the severe winter, suggesting that energy depletion did not cause mortality. Rather, osmoregulatory failure may have occurred during exposure to temperatures colder than 4°C for at least 1 week. Thus, the availability of warm (≥4°C), oxygenated water during winter may be critical to the survival of age-0 white crappies. In the northern portion of their range, winter temperatures may account for some of the recruitment variability common to white crappie populations.This research was funded by Federal Aid in Sport Fish Restoration Project F-69-P, administered jointly by U.S. Fish and Wildlife Service and Ohio Department of Natural Resources, Division of Wildlife, and the Department of Evolution, Ecology, and Organismal Biology at the Ohio State University

On Zurek's derivation of the Born rule

Recently, W. H. Zurek presented a novel derivation of the Born rule based on a mechanism termed environment-assisted invariance, or "envariance" [W. H. Zurek, Phys. Rev. Lett. 90(2), 120404 (2003)]. We review this approach and identify fundamental assumptions that have implicitly entered into it, emphasizing issues that any such derivation is likely to face.Comment: 8 pages; v2: minor clarifications added; v3: reference to Zurek's quant-ph/0405161 added. To appear in Foundations of Physics (Cushing Volume

Common Alzheimer's disease risk variant within the CLU gene affects white matter microstructure in young adults

There is a strong genetic risk for late-onset Alzheimer's disease (AD), but so far few gene variants have been identified that reliably contribute to that risk. A newly confirmed genetic risk allele C of the clusterin (CLU) gene variant rs11136000 is carried by similar to 88% of Caucasians. The C allele confers a 1.16 greater odds of developing late-onset AD than the T allele. AD patients have reductions in regional white matter integrity. We evaluated whether the CLU risk variant was similarly associated with lower white matter integrity in healthy young humans. Evidence of early brain differences would offer a target for intervention decades before symptom onset. We scanned 398 healthy young adults (mean age, 23.6 +/- 2.2 years) with diffusion tensor imaging, a variation of magnetic resonance imaging sensitive to white matter integrity in the living brain. We assessed genetic associations using mixed-model regression at each point in the brain to map the profile of these associations with white matter integrity. Each Callele copy of the CLU variant was associated with lower fractional anisotropy-a widely accepted measure of white matter integrity-in multiple brain regions, including several known to degenerate in AD. These regions included the splenium of the corpus callosum, the fornix, cingulum, and superior and inferior longitudinal fasciculi in both brain hemispheres. Young healthy carriers of the CLU gene risk variant showed a distinct profile of lower white matter integrity that may increase vulnerability to developing AD later in life

Numerical solution to a singular integro-differential equation from bridged crack theory

Models for completely or partially bridged cracks are derived from classical models of static elasticity. The problem of the elastic frictionless half-plane yields a singular integro-differential equation. This thesis addresses a derivation of a convergent numerical method for solving such an equation. Constructed numerical solution concurs the results of prior experimental and numerical analysis on the topic.California State University, Northridge. Department of Mathematics.Includes bibliographical references (leaf 26

By-with-through : raisons d’être et limites de l’approche opérationnelle américaine dans le cadre de la lutte contre le groupe État islamique en Irak et en Syrie

Ce Cahier du CÉRIUM examine l’approche « by-with-through » employée par les États- Unis dans le cadre de la lutte contre l’État islamique en Irak et en Syrie à partir de 2014. Ce modèle privilégiant le soutien à des forces locales chargées de la majeure partie des combats à un déploiement massif de troupes nationales semble répondre aux échecs des interventions américaines au Moyen-Orient et en Asie centrale du début des années 2000. L’article introduit ce mode d’action à faible empreinte, son application lors de l’engagement contre l’EI, et les raisons pouvant expliquer son usage par les États-Unis. L’analyse se penche ensuite sur les limites inhérentes à cette manière indirecte de mener la guerre ; que ce soit d’un point de vue éthique ou opérationnel. La conclusion ouvre finalement une réflexion sur l’avenir du modèle dans le cadre d’un système international tendant de plus en plus vers la bipolarité.This CÉRIUM report examines the “by-with-through” approach employed by the United States in the fight against the Islamic State in Iraq and Syria starting in 2014. This model, prioritizing support to local forces in charge of the bulk of ground combat over a massive deployment of national troops, appears to be a response to the failures of American interventions in the Middle East and Central Asia in the early 2000s. The article introduces this “light footprint” mode of action, its application in the battle against ISIS, and explores the reasons that may explain its use by the United States. The analysis then delves into the inherent limitations of this indirect way of conducting warfare, whether from an ethical or operational standpoint. The conclusion finally opens a reflection on the future of this model in the context of an international system increasingly tending toward bipolarity

The legend about sailing ship effects – Is it true or false? The example of cleaner propulsion technologies diffusion in the automotive industry

The global automotive industry is faced with major technological change in the field of propulsion systems. Due to low carbon emission regulations and a rising societal demand for sustainability, original equipment manufacturers (OEMs) are forced to innovate either in the conventional technology or in the technological alternatives such as electric drives or fuel cells. However, OEMs are only marginally switching to electromobility so far, but rather incrementally innovating traditional technologies. This behaviour can be described as sailing ship effect which contains the reaction of an old technology to a new technology by fostering innovation in the old technology. Firstly, the present study contributes to the discussion in literature on the sailing ship effect by combining its underlying ideas and consequences with the rationales of path dependence to demonstrate that such a behaviour may be individually economical rational. Based on these considerations, we respond to the call for further empirical investigation of the sailing ship effect. We show patent-based evidence that there has been a temporary sailing ship effect in the automotive industry concerning traditional and emerging propulsion systems and discuss implications for corporate technology strategy and policy

Dimensionality reduction beyond neural subspaces with slice tensor component analysis

Recent work has argued that large-scale neural recordings are often well described by patterns of coactivation across neurons. Yet the view that neural variability is constrained to a fixed, low-dimensional subspace may overlook higher-dimensional structure, including stereotyped neural sequences or slowly evolving latent spaces. Here we argue that task-relevant variability in neural data can also cofluctuate over trials or time, defining distinct ‘covariability classes’ that may co-occur within the same dataset. To demix these covariability classes, we develop sliceTCA (slice tensor component analysis), a new unsupervised dimensionality reduction method for neural data tensors. In three example datasets, including motor cortical activity during a classic reaching task in primates and recent multiregion recordings in mice, we show that sliceTCA can capture more task-relevant structure in neural data using fewer components than traditional methods. Overall, our theoretical framework extends the classic view of low-dimensional population activity by incorporating additional classes of latent variables capturing higher-dimensional structure