129 research outputs found

    Foraging Ecology and Population Dynamics of Collared Pikas in Southwestern Yukon

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    Sentencing Guidelines and Judicial Discretion: Quasi-experimental Evidence from Human Calculation Errors

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    There is a debate about whether advisory non-binding sentencing guidelines affect the sentences outcomes of individuals convicted in jurisdictions with this sentencing framework. Identifying the impact of sentencing guidelines is a difficult empirical problem because court actors may have preferences for sentencing severity that are correlated with the preferences that are outlined in the guidelines. But, in Maryland, ten percent of the recommended sentences computed in the guideline worksheets contain calculation errors. We use this unique source of quasi-experimental variation to quantify the extent to which sentencing guidelines influence policy outcomes. Among drug offenses, we find that the direct impact of the guidelines is roughly œ the size of the overall correlation between recommendations and outcomes. For violent offenses, we find the same œ discount for sentence recommendations that are higher than they should have been, but more responsiveness to recommendations that are too low. We find no evidence that the guidelines themselves directly affect discretion for property offenders, perhaps because judges generally have substantial experience with property cases and therefore do not rely on the errant information. Sentences are more sensitive to both accurate and inaccurate recommendations for crimes that occur less frequently and have more complicated sentencing. This suggests that when the court has more experience, the recommendations have less influence. More tentative findings suggest that, further down the decision chain, parole boards counteract the remaining influence of the guidelines.

    Evidence for Selective Caching by Arctic Ground Squirrels Living in Alpine Meadows in the Yukon

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    Male arctic ground squirrels (Spermophilus parryii) rely on food they cached the previous year for the energy they need to compete for mates each spring. We collected cheek-pouch contents of arctic ground squirrels trapped during three summers (2000–02) as an indication of what squirrels cached. Among adults, both males and females carried material in their cheek pouches, but males did so more frequently than females (4.4% vs. 0.6% of captures). Males carried material later in the summer than females, and also carried different material (seeds and rhizomes as opposed to nesting material). These differences probably reflect different purposes of cheek-pouch contents—females carried material for immediate use, whereas males carried food for caching. Only 24 of over 100 species of vascular plants growing at our alpine study site were carried, and presumably cached, by male arctic ground squirrels. The seeds or rhizomes of one species, Polygonum viviparum, were found in over 90% of cheek-pouch contents examined, even though that species grew at relatively low density and was no more common than another species in the same genus (Polygonum bistorta) that was never found in cheek-pouch contents. Collectively, this evidence indicates that males are highly selective in what species they cache. Many of the species carried by arctic ground squirrels in this study have also been found in Pleistocene fossil caches from central Yukon, indicating that food preferences of this species may have remained stable over time.Les spermophiles arctiques mĂąles (Spermophilus parryii) dĂ©pendent de la nourriture qu’ils ont cachĂ©e l’annĂ©e prĂ©cĂ©dente pour obtenir l’énergie dont ils ont besoin pour se trouver une compagne d’accouplement au printemps. On a recueilli le contenu des abajoues de spermophiles arctiques capturĂ©s pendant trois Ă©tĂ©s (de 2000 Ă  2002) pour obtenir un aperçu de ce qu’ils emmagasinaient. Les spermophiles adultes, tant mĂąles que femelles, transportaient des matĂ©riaux dans leurs abajoues, mais c’était plus souvent le cas chez les mĂąles que chez les femelles (4,4 % par rapport Ă  0,6 % des spermophiles capturĂ©s). Les mĂąles transportaient des matĂ©riaux plus tard pendant l’étĂ© que les femelles, sans compter que ces matĂ©riaux Ă©taient diffĂ©rents (des graines et des rhizomes par opposition Ă  des matĂ©riaux destinĂ©s Ă  la nidification). Ces diffĂ©rences sont probablement le reflet de la raison d’ĂȘtre diffĂ©rente du contenu des abajoues — les femelles transportaient des matĂ©riaux dont elles allaient se servir immĂ©diatement, tandis que les mĂąles transportaient des aliments qu’ils allaient mettre en rĂ©serve. Sur la centaine d’espĂšces de plantes vasculaires poussant au site alpin que nous avons Ă©tudiĂ©, seulement 24 d’entre elles Ă©taient prĂ©sentes. Ces plantes avaient probablement Ă©tĂ© mises en rĂ©serve par les spermophiles arctiques mĂąles. Les graines ou les rhizomes d’une espĂšce, soit le Polygonum viviparum, ont Ă©tĂ© trouvĂ©s dans plus de 90 % du contenu des abajoues examinĂ©, mĂȘme si ces espĂšces poussaient selon des densitĂ©s relativement faibles et qu’elles n’étaient pas plus courantes qu’une autre espĂšce du mĂȘme genre (Polygonum bistorta) qui ne se retrouvait jamais dans le contenu des abajoues. Dans l’ensemble, cela indique que les mĂąles font preuve d’une grande sĂ©lectivitĂ© quant aux espĂšces qu’ils mettent en rĂ©serve. Grand nombre des espĂšces transportĂ©es par les spermophiles arctiques visĂ©s par cette Ă©tude ont Ă©galement Ă©tĂ© retrouvĂ©es dans les caches fossiles du PlĂ©istocĂšne du centre du Yukon, ce qui laisse croire que les prĂ©fĂ©rences alimentaires de cette espĂšce n’ont guĂšre changĂ© au fil du temps

    Morphological change in Newfoundland caribou: Effects of abundance and climate

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    The demographic and environmental influences on large mammal morphology are central questions in ecology. We investigated the effects of population abundance and climate on body size and number of male antler points for the La Poile and Middle Ridge caribou (Rangifer tarandus, L. 1758) herds, Newfoundland, Canada. Across 40 years and 20-fold changes in abundance, adult males and females exhibited diminished stature as indicated by jawbone size (diastema and total mandible length) and the number of antler points at the time of harvest. Associations between jawbone size and population abundance at birth were consistently negative for both herds, both sexes, and all age classes. Large-scale climate patterns, as measured by the North Atlantic Oscillation in the winter prior to birth, were also negatively associated with jawbone size. Declines in male antler size, as measured by the number of antler points, were not well predicted by either abundance or climate, suggesting other factors (e.g., current, rather than latent, foraging conditions) may be involved. We conclude that these morphological changes indicate competition for food resources

    Prehospital resuscitation with hypertonic saline-dextran modulates inflammatory, coagulation and endothelial activation marker profiles in severe traumatic brain injured patients

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    <p>Abstract</p> <p>Background</p> <p>Traumatic brain injury (TBI) initiates interrelated inflammatory and coagulation cascades characterized by wide-spread cellular activation, induction of leukocyte and endothelial cell adhesion molecules and release of soluble pro/antiinflammatory cytokines and thrombotic mediators. Resuscitative care is focused on optimizing cerebral perfusion and reducing secondary injury processes. Hypertonic saline is an effective osmotherapeutic agent for the treatment of intracranial hypertension and has immunomodulatory properties that may confer neuroprotection. This study examined the impact of hypertonic fluids on inflammatory/coagulation cascades in isolated head injury.</p> <p>Methods</p> <p>Using a prospective, randomized controlled trial we investigated the impact of prehospital resuscitation of severe TBI (GCS < 8) patients using 7.5% hypertonic saline in combination with 6% dextran-70 (HSD) <it>vs </it>0.9% normal saline (NS), on selected cellular and soluble inflammatory/coagulation markers. Serial blood samples were drawn from 65 patients (30 HSD, 35 NS) at the time of hospital admission and at 12, 24, and 48-h post-resuscitation. Flow cytometry was used to analyze leukocyte cell-surface adhesion (CD62L, CD11b) and degranulation (CD63, CD66b) molecules. Circulating concentrations of soluble (s)L- and sE-selectins (sL-, sE-selectins), vascular and intercellular adhesion molecules (sVCAM-1, sICAM-1), pro/antiinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL-10)], tissue factor (sTF), thrombomodulin (sTM) and D-dimers (D-D) were assessed by enzyme immunoassay. Twenty-five healthy subjects were studied as a control group.</p> <p>Results</p> <p>TBI provoked marked alterations in a majority of the inflammatory/coagulation markers assessed in all patients. Relative to control, NS patients showed up to a 2-fold higher surface expression of CD62L, CD11b and CD66b on polymorphonuclear neutrophils (PMNs) and monocytes that persisted for 48-h. HSD blunted the expression of these cell-surface activation/adhesion molecules at all time-points to levels approaching control values. Admission concentrations of endothelial-derived sVCAM-1 and sE-selectin were generally reduced in HSD patients. Circulating sL-selectin levels were significantly elevated at 12 and 48, but not 24 h post-resuscitation with HSD. TNF-α and IL-10 levels were elevated above control throughout the study period in all patients, but were reduced in HSD patients. Plasma sTF and D-D levels were also significantly lower in HSD patients, whereas sTM levels remained at control levels.</p> <p>Conclusions</p> <p>These findings support an important modulatory role of HSD resuscitation in attenuating the upregulation of leukocyte/endothelial cell proinflammatory/prothrombotic mediators, which may help ameliorate secondary brain injury after TBI.</p> <p>Trial registration</p> <p>NCT00878631.</p

    The European general data protection regulation:Challenges and considerations for iPSC researchers and biobanks

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    Increasingly, human induced pluripotent stem cells (iPSC) and their associated genetic and clinical information are being used in a wide range of applications, with large biobanks being established to support and increase their scientific use. The new European General Data Protection Regulations, which comes into effect in 2018, will have implications for biobanks that generate, store and allow research access to iPSC. This paper describes some of the challenges that iPSC biobanks face and suggests some points for the development of appropriate governance structures to address these new requirements. These suggestions also have implications for iPSC research in general

    Lessons Learned During the Implementation of a Cold Gas Propulsion System for the SunRISE Mission

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    The SunRISE mission utilizes a two-phase cold gas propulsion system, which provides several advantages over other cold gas systems but experienced challenges during assembly and testing. Since 2020, Georgia Tech Research Corporation (GTRC), Utah State University Space Dynamics Laboratory (SDL), and the Jet Propulsion Laboratory (FPL) have implemented several improvements to the SunRISE propulsion system. The SunRISE propulsion system leverages an additively manufactured monolithic structure, commercial off-the-shelf (COTS) valves and transducers, and the benign working fluid R-236fa to provide a suitable propulsion system for the SunRise mission. While the GTRC propulsion system had been developed for other missions, the multi-organizational team found and corrected several previously undetected design issues, including filters with highly variable flow performance, solenoid valve drive circuit issues, and inconsistencies in the tank additive manufacturing process that impacted manufacturing yield, thrust consistency, and quality of seals. Leaks in metallic fittings were also identified, and process improvements were put in place to mitigate them. Solenoid valve stiction was the last issue which was mitigated through valve screening and drive circuit adjustments. In this paper, we present lessons learned from the SunRISE propulsion system effort to aid future teams in identifying and addressing similar issues

    Microbial communities mediating algal detritus turnover under anaerobic conditions

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    Background Algae encompass a wide array of photosynthetic organisms that are ubiquitously distributed in aquatic and terrestrial habitats. Algal species often bloom in aquatic ecosystems, providing a significant autochthonous carbon input to the deeper anoxic layers in stratified water bodies. In addition, various algal species have been touted as promising candidates for anaerobic biogas production from biomass. Surprisingly, in spite of its ecological and economic relevance, the microbial community involved in algal detritus turnover under anaerobic conditions remains largely unexplored. Results Here, we characterized the microbial communities mediating the degradation of Chlorella vulgaris (Chlorophyta), Chara sp. strain IWP1 (Charophyceae), and kelp Ascophyllum nodosum (phylum Phaeophyceae), using sediments from an anaerobic spring (Zodlteone spring, OK; ZDT), sludge from a secondary digester in a local wastewater treatment plant (Stillwater, OK; WWT), and deeper anoxic layers from a seasonally stratified lake (Grand Lake O’ the Cherokees, OK; GL) as inoculum sources. Within all enrichments, the majority of algal biomass was metabolized within 13–16 weeks, and the process was accompanied by an increase in cell numbers and a decrease in community diversity. Community surveys based on the V4 region of the 16S rRNA gene identified different lineages belonging to the phyla Bacteroidetes, Proteobacteria (alpha, delta, gamma, and epsilon classes), Spirochaetes, and Firmicutes that were selectively abundant under various substrate and inoculum conditions. Within all kelp enrichments, the microbial communities structures at the conclusion of the experiment were highly similar regardless of the enrichment source, and were dominated by the genus Clostridium, or family Veillonellaceae within the Firmicutes. In all other enrichments the final microbial community was dependent on the inoculum source, rather than the type of algae utilized as substrate. Lineages enriched included the uncultured groups VadinBC27 and WCHB1-69 within the Bacteroidetes, genus Spirochaeta and the uncultured group SHA-4 within Spirochaetes, Ruminococcaceae, Lachnospiraceae, Yongiibacter, Geosporobacter, and Acidaminobacter within the Firmicutes, and genera Kluyvera, Pantoea, Edwardsiella and Aeromonas, and Buttiauxella within the Gamma-Proteobaceteria order Enterobacteriales. Conclusions Our results represent the first systematic survey of microbial communities mediating turnover of algal biomass under anaerobic conditions, and highlights the diversity of lineages putatively involved in the degradation process
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