1,177 research outputs found

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

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    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

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    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

    Forced Smoking Abstinence: Not Enough for Smoking Cessation

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    Importance: Millions of Americans are forced to quit smoking as they enter tobacco-free prisons and jails, but most return to smoking within days of release. Interventions are needed to sustain tobacco abstinence after release from incarceration. Objective: To evaluate the extent to which the WISE intervention (Working Inside for Smoking Elimination), based on motivational interviewing (MI) and cognitive behavioral therapy (CBT), decreases relapse to smoking after release from a smoke-free prison. Design: Participants were recruited approximately 8 weeks prior to their release from a smoke-free prison and randomized to 6 weekly sessions of either education videos (control) or the WISE intervention. Setting: A tobacco-free prison in the United States. Participants: A total of 262 inmates (35% female). Main Outcome Measure: Continued smoking abstinence was defined as 7-days point-prevelance abstinence validated by urine cotinine measurement. Results: At the 3-week follow-up, 25% of the participants in the WISE intervention (31 of 122) and 7% of the control participants (9 of 125) continued to be tobacco-abstinent (odds ration [OR], 4.4; 95% CI, 2.0-9.7). In addition to the intervention, Hispanic ethnicity, a plan to remain abstinent, and being incarcerated for more than 6 months were all associated with increased likelihood of remaining abstinent. In the logistical regression analysis, participants randomized to the WISE intervention were 6.6 times more likely to remain tobacco abstinent at the 3-week follow up than those randomized to the control condition (95% CI, 2.5-17.0). Nonsmokers at the 3-week follow-up had an additional follow-up 3 months after release, and overall 12% of the participants in the WISER intervention (14 of 122) and 2% of the control participants (3 of 125) were tobacco free at 3 months, as confirmed by urine cotinine measurement (OR, 5.3; 95% CI, 1.4-23.8). Conclusions and Relevance: Forced tobacco abstinence alone during incarceration has little impact on postrelease smoking status. A behavioral intervention provided prior to release greatly improves cotinine-confirmed smoking cessation in the community. Trial Registration: clinicaltrials.gov Identifier: NCT0112258

    Changes in Depression and Stress after Release from a Tobacco-Free Prison in the United States

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    Prior research has found high levels of depression and stress among persons who are incarcerated in the United States (U.S.). However, little is known about changes in depression and stress levels among inmates post-incarceration. The aim of this study was to examine changes in levels of depression and stress during and after incarceration in a tobacco-free facility. Questionnaires that included valid and reliable measures of depression and stress were completed by 208 male and female inmates approximately eight weeks before and three weeks after release from a northeastern U.S. prison. Although most inmates improved after prison, 30.8% had a worsening in levels of depression between baseline and the three-week follow-up. In addition, 29.8% had a worsening in levels of stress after release than during incarceration. While it is not surprising that the majority of inmates reported lower levels of depression and stress post-incarceration, a sizable minority had an increase in symptoms, suggesting that environmental stressors may be worse in the community than in prison for some inmates. Further research is needed to address depression and stress levels during and after incarceration in order for inmates to have a healthier transition back into the community and to prevent repeat incarcerations

    NACHOS, a CubeSat-Based High-Resolution UV-Visible Hyperspectral Imager for Remote Sensing of Trace Gases: System Overview, Science Objectives, and Preliminary Results

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    The Nano-satellite Atmospheric Chemistry Hyperspectral Observation System (NACHOS) is a high-throughput (f/2.9), high spectral resolution (1.3 nm optical, 0.57 nm sampling) hyperspectral imager covering the 300-500 nm spectral region with 350 spectral bands. The combined 1.5U instrument payload and 1.5U spacecraft bus comprise a 3U CubeSat. Spectroscopically similar to NASA’s Ozone Monitoring Instrument (OMI), which provides wide-field coverage at ~20 km spatial resolution, NACHOS offers complementary targeted measurements at far higher spatial resolution of ~0.4 km/pixel from 500 km altitude over its 15 ̊ across-track field of view. NACHOS incorporates highly streamlined onboard gas-retrieval algorithms, alleviating the need to routinely downlink massive hyperspectral data cubes. This paper discusses the instrument design, requirements leading to it, preliminary results, and science goals, including monitoring NO2 as a proxy for anthropogenic greenhouse gases, low-level degassing of SO2 and halogen oxides at pre-eruptive volcanoes, and formaldehyde from wildfires. Aiming for an eventual many-satellite constellation providing both high spatial resolution and frequent target revisits, the current NACHOS project is launching two CubeSats, the first already launched to the International Space Station aboard the NG-17 Cygnus vehicle on February 19, 2022 and awaiting deployment to its final orbit in June, and the second launching June 29, 2022

    A proposal for a coordinated effort for the determination of brainwide neuroanatomical connectivity in model organisms at a mesoscopic scale

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    In this era of complete genomes, our knowledge of neuroanatomical circuitry remains surprisingly sparse. Such knowledge is however critical both for basic and clinical research into brain function. Here we advocate for a concerted effort to fill this gap, through systematic, experimental mapping of neural circuits at a mesoscopic scale of resolution suitable for comprehensive, brain-wide coverage, using injections of tracers or viral vectors. We detail the scientific and medical rationale and briefly review existing knowledge and experimental techniques. We define a set of desiderata, including brain-wide coverage; validated and extensible experimental techniques suitable for standardization and automation; centralized, open access data repository; compatibility with existing resources, and tractability with current informatics technology. We discuss a hypothetical but tractable plan for mouse, additional efforts for the macaque, and technique development for human. We estimate that the mouse connectivity project could be completed within five years with a comparatively modest budget.Comment: 41 page

    Multi-site genetic analysis of diffusion images and voxelwise heritability analysis : a pilot project of the ENIGMA–DTI working group

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    The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium was set up to analyze brain measures and genotypes from multiple sites across the world to improve the power to detect genetic variants that influence the brain. Diffusion tensor imaging (DTI) yields quantitative measures sensitive to brain development and degeneration, and some common genetic variants may be associated with white matter integrity or connectivity. DTI measures, such as the fractional anisotropy (FA) of water diffusion, may be useful for identifying genetic variants that influence brain microstructure. However, genome-wide association studies (GWAS) require large populations to obtain sufficient power to detect and replicate significant effects, motivating a multi-site consortium effort. As part of an ENIGMA–DTI working group, we analyzed high-resolution FA images from multiple imaging sites across North America, Australia, and Europe, to address the challenge of harmonizing imaging data collected at multiple sites. Four hundred images of healthy adults aged 18–85 from four sites were used to create a template and corresponding skeletonized FA image as a common reference space. Using twin and pedigree samples of different ethnicities, we used our common template to evaluate the heritability of tract-derived FA measures. We show that our template is reliable for integrating multiple datasets by combining results through meta-analysis and unifying the data through exploratory mega-analyses. Our results may help prioritize regions of the FA map that are consistently influenced by additive genetic factors for future genetic discovery studies. Protocols and templates are publicly available at (http://enigma.loni.ucla.edu/ongoing/dti-working-group/)

    Mapping interactions between the RNA chaperone FinO and its RNA targets

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    Bacterial conjugation is regulated by two-component repression comprising the antisense RNA FinP, and its protein co-factor FinO. FinO mediates base-pairing of FinP to the 5′-untranslated region (UTR) of traJ mRNA, which leads to translational inhibition of the transcriptional activator TraJ and subsequent down regulation of conjugation genes. Yet, little is known about how FinO binds to its RNA targets or how this interaction facilitates FinP and traJ mRNA pairing. Here, we use solution methods to determine how FinO binds specifically to its minimal high affinity target, FinP stem–loop II (SLII), and its complement SLIIc from traJ mRNA. Ribonuclease footprinting reveals that FinO contacts the base of the stem and the 3′ single-stranded tails of these RNAs. The phosphorylation or oxidation of the 3′-nucleotide blocks FinO binding, suggesting FinO binds the 3′-hydroxyl of its RNA targets. The collective results allow the generation of an energy-minimized model of the FinO–SLII complex, consistent with small-angle X-ray scattering data. The repression complex model was constrained using previously reported cross-linking data and newly developed footprinting results. Together, these data lead us to propose a model of how FinO mediates FinP/traJ mRNA pairing to down regulate bacterial conjugation

    НАПРАВЛЕНИЯ СОВЕРШЕНСТВОВАНИЯ ОБРУДОВАНИЯ ДЛЯ ФЛОТАЦИОННОГО ОБОГАЩЕНИЯ ТОНКОДИСПЕРСНыХ МАТЕРИАЛОВ

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    Проблема и ее связь с научными и практическими задачами. В связи с тем, что в поступающем на обогатительные фабрики сырье содержится до 30% ма-териала крупностью менее 1 мм, роль процесса флотации существенно возрас-тает. Этому способствует и возможность создания достаточно простых замкну-тых водно-шламовых схем, включающих флотацию в качестве основного эле-мента очистки оборотных вод. Многими исследованиями, которые проводились ранее и продолжают выполняться и в настоящее время, установлены направле-ния совершенствования этого достаточно сложного физико-химического про-цесс
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