1,730 research outputs found

    Public Policy, Women, and Confinement: A Plea for Reasonableness

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    This veteran correctional administrator reviews the explosion of numbers of female offenders confined in the United States today. The article explores the myriad causes and effects of this shift in public policy and notes the negative impact of today\u27s policy outcomes on individual offenders, correctional systems, and our society. The author argues for a modification of policy to a more rational approach to judicial sentencing

    Resolving structural variability in network models and the brain

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    Large-scale white matter pathways crisscrossing the cortex create a complex pattern of connectivity that underlies human cognitive function. Generative mechanisms for this architecture have been difficult to identify in part because little is known about mechanistic drivers of structured networks. Here we contrast network properties derived from diffusion spectrum imaging data of the human brain with 13 synthetic network models chosen to probe the roles of physical network embedding and temporal network growth. We characterize both the empirical and synthetic networks using familiar diagnostics presented in statistical form, as scatter plots and distributions, to reveal the full range of variability of each measure across scales in the network. We focus on the degree distribution, degree assortativity, hierarchy, topological Rentian scaling, and topological fractal scaling---in addition to several summary statistics, including the mean clustering coefficient, shortest path length, and network diameter. The models are investigated in a progressive, branching sequence, aimed at capturing different elements thought to be important in the brain, and range from simple random and regular networks, to models that incorporate specific growth rules and constraints. We find that synthetic models that constrain the network nodes to be embedded in anatomical brain regions tend to produce distributions that are similar to those extracted from the brain. We also find that network models hardcoded to display one network property do not in general also display a second, suggesting that multiple neurobiological mechanisms might be at play in the development of human brain network architecture. Together, the network models that we develop and employ provide a potentially useful starting point for the statistical inference of brain network structure from neuroimaging data.Comment: 24 pages, 11 figures, 1 table, supplementary material

    Robust Detection of Dynamic Community Structure in Networks

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    We describe techniques for the robust detection of community structure in some classes of time-dependent networks. Specifically, we consider the use of statistical null models for facilitating the principled identification of structural modules in semi-decomposable systems. Null models play an important role both in the optimization of quality functions such as modularity and in the subsequent assessment of the statistical validity of identified community structure. We examine the sensitivity of such methods to model parameters and show how comparisons to null models can help identify system scales. By considering a large number of optimizations, we quantify the variance of network diagnostics over optimizations (`optimization variance') and over randomizations of network structure (`randomization variance'). Because the modularity quality function typically has a large number of nearly-degenerate local optima for networks constructed using real data, we develop a method to construct representative partitions that uses a null model to correct for statistical noise in sets of partitions. To illustrate our results, we employ ensembles of time-dependent networks extracted from both nonlinear oscillators and empirical neuroscience data.Comment: 18 pages, 11 figure

    Latent profile analysis of accelerometer-measured sleep, physical activity, and sedentary time and differences in health characteristics in adult women.

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    ObjectivesIndependently, physical activity (PA), sedentary behavior (SB), and sleep are related to the development and progression of chronic diseases. Less is known about how rest-activity behaviors cluster within individuals and how rest-activity behavior profiles relate to health. In this study we aimed to investigate if adult women cluster into profiles based on how they accumulate rest-activity behavior (including accelerometer-measured PA, SB, and sleep), and if participant characteristics and health outcomes differ by profile membership.MethodsA convenience sample of 372 women (mean age 55.38 + 10.16) were recruited from four US cities. Participants wore ActiGraph GT3X+ accelerometers on the hip and wrist for a week. Total daily minutes in moderate-to-vigorous PA (MVPA) and percentage of wear-time spent in SB was estimated from the hip device. Total sleep time (hours/minutes) and sleep efficiency (% of in bed time asleep) were estimated from the wrist device. Latent profile analysis (LPA) was performed to identify clusters of participants based on accumulation of the four rest-activity variables. Adjusted ANOVAs were conducted to explore differences in demographic characteristics and health outcomes across profiles.ResultsRest-activity variables clustered to form five behavior profiles: Moderately Active Poor Sleepers (7%), Highly Actives (9%), Inactives (41%), Moderately Actives (28%), and Actives (15%). The Moderately Active Poor Sleepers (profile 1) had the lowest proportion of whites (35% vs 78-91%, p < .001) and college graduates (28% vs 68-90%, p = .004). Health outcomes did not vary significantly across all rest-activity profiles.ConclusionsIn this sample, women clustered within daily rest-activity behavior profiles. Identifying 24-hour behavior profiles can inform intervention population targets and innovative behavioral goals of multiple health behavior interventions

    Stress-Energy Tensor for the Massless Spin 1/2 Field in Static Black Hole Spacetimes

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    The stress-energy tensor for the massless spin 1/2 field is numerically computed outside and on the event horizons of both charged and uncharged static non-rotating black holes, corresponding to the Schwarzschild, Reissner-Nordstrom and extreme Reissner-Nordstr\"om solutions of Einstein's equations. The field is assumed to be in a thermal state at the black hole temperature. Comparison is made between the numerical results and previous analytic approximations for the stress-energy tensor in these spacetimes. For the Schwarzschild (charge zero) solution, it is shown that the stress-energy differs even in sign from the analytic approximation. For the Reissner-Nordstrom and extreme Reissner-Nordstrom solutions, divergences predicted by the analytic approximations are shown not to exist.Comment: 5 pages, 4 figures, additional discussio

    President\u27s Note

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    <p>Black lines indicate best linear fit to the data (dashed) and model (solid) networks. In panel <i>(B)</i>, the parameter values used for the affinity model are the following: , , and .</p

    A poke in the eye: Inhibiting HIV-1 protease through its flap-recognition pocket

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    A novel mechanism of inhibiting HIV-1 protease (HIVp) is presented. Using computational solvent mapping to identify complementary interactions and the Multiple Protein Structure method to incorporate protein flexibility, we generated a receptor-based pharmacophore model of the flexible flap region of the semiopen, apo state of HIVp. Complementary interactions were consistently observed at the base of the flap, only within a cleft with a specific structural role. In the closed, bound state of HIVp, each flap tip docks against the opposite monomer, occupying this cleft. This flap-recognition site is filled by the protein and cannot be identified using traditional approaches based on bound, closed structures. Virtual screening and dynamics simulations show how small molecules can be identified to complement this cleft. Subsequent experimental testing confirms inhibitory activity of this new class of inhibitor. This may be the first new inhibitor class for HIVp since dimerization inhibitors were introduced 17 years ago. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 643–652, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at [email protected] Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58588/1/20993_ftp.pd

    Herbivorous Fish Populations Respond Positively to a Shipwreck Removal and Associated Alteration of Benthic Habitat

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    Shipwrecks can have significant localized effects when grounded on shallow coral reefs. These effects are not limited to the immediate physical damage, but can have wide-spread and lasting impacts due to alteration of the chemical makeup of the surrounding water column. This can subsequently impact the growth of benthic organisms, often leading to phase shifts and high levels of mortality of corals in the vicinity of the wreck. At Palmyra atoll, the grounding of a longline fishing vessel on the shallow reef terrace is associated with a phase shift to the corallimorph, Rhodactis howesii. In 2013, a wreck removal effort initiated by the US Department of Fish and Wildlife resulted in the successful extraction and disposal of the wreckage, after which the density and percent cover of R. howesii in the immediate vicinity of the wreck site dropped precipitously. Here, we document the response of the fish community to the wreck removal and localized decline in R. howesii. We show that the biomass of scarid parrotfishes and acanthurid surgeonfishes and unicornfishes (primarily herbivores) increased after the removal of the wreck, while biomass of chaetodontid butterflyfishes (primarily invertivores, many species are known to feed on coelenterate polyps) declined over the study period. The density of small scarids and acanthurids also increased, but only after a few years post removal. Overall these results indicate that Palmyra’s unfished herbivore population has rapidly responded to the removal of the wreck and associated decrease in corallimorph cover, can maintain high levels of grazing where space is made available for colonization of early successional algae species, and may have the potential to facilitate reef recovery

    Aquatic biosurvey of the Lovell River on UNH land

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    We assessed the physical, chemical and biological conditions at two sites along the Lovell River on University of New Hampshire (UNH) -owned conservation land. The discharge was 4.4 m3 s-1 at Site 1 and 5.7 m3 s -1 downstream at Site 2. Canopy coverage ranged from 8-25%. Canopy was dominated by Eastern Hemlock (79-84%). Much of the stream was strewn with large boulders and the substrate consisted of rocks of highly variable sizes ( 3-549 cm dia.). Specific conductivity (22.1-23.3 µS), pH (6.4) and temperature (7.9-8.3 °C) varied little between sites. Macro-invertebrate bio-indices indicated either excellent water quality with no apparent organic pollution (3.0/10) or good water quality with possible slight organic pollution (4.4/10)

    Morphometric characteristics of pyloric gastric glands at experimental acute gastritis and after administration of ‘Platex-Placental’ medication on the background of experimental acute gastritis

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    В роботі встановлена динаміка змін середніх метричних показників воротарних залоз шлунка при гострому експериментальному гастриті, після введення препарату «Платекс-плацентарний» (кріоконсервована тканина плаценти) та після введення препарату «Платекс-плацентарний» на тлі гострого експериментального гастриту. Виявлена позитивна динаміка дії препарату «Платекс-плацентарний» на швидкість перебігу та перебудову захисних властивостей воротарних залоз у відповідь на гострий запальний процес.; В работе установлена динамика изменений средних показателей привратниковых желез желудка при остром экспериментальном гастрите, после введения препарата «Платекс-плацентарный» (криоконсервированная ткань плаценты) и после введения препарата «Платекс-плацентарный» на фоне острого экспериментального гастрита. Выявлена положительная динамика действия препарата «Платекс-плацентарный» на скорость протекания и перестройку защитных свойств привратниковых желез в ответ на острый воспалительный процесс.; The study descrides the dynamics of changes in average indices of pyloric gastric glands at experimental acute gastritis, after administration of ‘Platex-Placental’ medication, and after administration of ‘Platex-Placental’ medication on a background of experimental acute gastritis. The positive outcomes were found after administration of ‘Platex-Placental’ medication in terms of inflammation course as well as reorganization of defence peculiarities of pyloric glands as a response to an acute inflammation
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