586 research outputs found

    Foraging Behavior of Swainson\u27s Thrushes (Catharus ustulatus) During Spring Migration through Arkansas

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    Foraging behavior of Swainson’s Thrushes on spring migration was studied in western Arkansas in the spring of 2013 and 2014. Observations were made in two forested field sites, one of them urban and the other suburban. The former had a significantly higher woody stem area (cm2) than the latter. For each foraging observation, the following three parameters were noted: Foraging Stratum (Ground, Shrub, Sapling, Sub canopy, and Canopy); Foraging Substrate (Ground/Litter, Herb, Foliage, Bark, and Air); and Foraging Maneuver (Glean, Probe, Dive/Glean, Hover, Jump Hover, and Hawking). We tested the hypotheses that these foraging variables differed significantly between the urban and suburban sites, and between the two years. These hypotheses were rejected for all three parameters. The consolidated data from both the sites and years revealed that a significantly higher proportion (67%) of the observations were on the Ground stratum, compared to the Shrub (13.7%) and Sapling strata (13%). Similarly, a significantly higher proportion (66%) of the foraging substrate used was Ground/Litter, followed by Foliage (16.7%) and Bark (15.8%). Gleaning was the most common foraging maneuver used (71.5%), and was significantly higher than Probing (12.3%) and Dive Gleaning (8.4%)

    A New Extension of the Binomial Error Model for Responses to Items of Varying Difficulty in Educational Testing and Attitude Surveys

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    We put forward a new item response model which is an extension of the binomial error model first introduced by Keats and Lord. Like the binomial error model, the basic latent variable can be interpreted as a probability of responding in a certain way to an arbitrarily specified item. For a set of dichotomous items, this model gives predictions that are similar to other single parameter IRT models (such as the Rasch model) but has certain advantages in more complex cases. The first is that in specifying a flexible two-parameter Beta distribution for the latent variable, it is easy to formulate models for randomized experiments in which there is no reason to believe that either the latent variable or its distribution vary over randomly composed experimental groups. Second, the elementary response function is such that extensions to more complex cases (e.g., polychotomous responses, unfolding scales) are straightforward. Third, the probability metric of the latent trait allows tractable extensions to cover a wide variety of stochastic response processes

    Steps to Growing Up Healthy: a Pediatric Primary Care Based Obesity Prevention Program for Young Children

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    Background Leading medical organizations have called on primary care pediatricians to take a central role in the prevention of childhood obesity. Weight counseling typically has not been incorporated into routine pediatric practice due to time and training constraints. Brief interventions with simple behavior change messages are needed to reach high-risk children, particularly Latino and Black children who are disproportionately affected by obesity and related comorbidities. Steps to Growing Up Healthy (Added Value) is a randomized controlled trial testing the efficacy of brief motivational counseling (BMC) delivered by primary care clinicians and the added value of supplementing BMC with monthly contact by community health workers (CHW) in the prevention/reversal of obesity in Latino and Black children ages 2-4 years old. Methods/Design Mother-child dyads (targeted n=150) are recruited for this 12-month randomized trial at an inner-city pediatric primary care clinic and randomized to: 1) BMC delivered by clinicians and nurses at well, sick, and WIC visits with the goal of reducing obesogenic behaviors (BMC); 2) BMC plus monthly phone calls by a CHW (BMC+Phone); or 3) BMC plus monthly home visits by a CHW (BMC+Home). During BMC, the medical team facilitates the selection of a specific goal (i.e., reduce sugar sweetened beverage consumption) that is meaningful to the mother and teaches the mother simple behavioral strategies. Monthly contacts with CHWs are designed to identify and overcome barriers to goal progress. Dyads are assessed at baseline and 12 months and the primary outcome is change in the child’s BMI percentile. We hypothesize that BMC+Phone and BMC+Home will produce greater reductions in BMI percentiles than BMC alone and that BMC+Home will produce greater reductions in BMI percentiles than BMC+Phone. Discussion Steps to Growing Up Healthy will provide important information about whether a brief primary care-based intervention that utilizes a motivational interviewing and goal setting approach can be incorporated into routine care and is sufficient to prevent/reverse obesity in young children. The study will also explore whether monthly contact with a community health worker bridges the gap between the clinic and the community and is an effective strategy for promoting obesity prevention in high-risk families

    Mediator role of presence of meaning and self-esteem in the relationship of social support and death anxiety

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    IntroductionDeath anxiety has increased following the COVID-19 pandemic. Although terror management theory has suggested social support, presence of meaning and self-esteem functioned as death anxiety buffers, few existing works have explored the mechanism of how social support, presence of meaning, and self-esteem buffer death anxiety. To identify these mechanisms is the aim of this study.MethodsOur cross-sectional study was conducted with 1167 people in China from 19 May 2020 to 1 June 2020 during the COVID-19 outbreak. The average age of participants was 26 years. Data were by questionnaire, including demographic information, the Templer's Death anxiety scale, the multidimensional scale of perceived social support, the presence of meaning scale, and the Rosenberg self-esteem scale.ResultsResults using structural equation modeling showed presence of meaning and self-esteem fully mediated the relationship between social support and death anxiety, respectively and sequentially. The proposed model showed good fit of indices: χ2 = 243.384, df = 58, p < 0.001; CFI = 0.968, TLI = 0.954, RMSEA = 0.052, SRMR = 0.044.DiscussionThis study demonstrates significant mediator roles of presence of meaning and self-esteem in the relationship of social support and death anxiety. Multi-component interventions are needed to manage death anxiety by targeting increasing social support, presence of meaning and self-esteem and increasing presence of meaning and self-esteem when social support is diminished in the pandemic

    Imagining and reimagining the future of special and inclusive education

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    “Reimagination” is required to create a new vision of education that better serves individuals with disabilities. Imagination is a way of conceiving possibilities and probabilities. The future of special education is imagined within the limits of possibility and probability of “appropriate” education for children with special educational needs and disabilities. Education is reimagined for full inclusion without special education and an alternative reimagination of inclusive special education. Particular attention is given to the administrative structure of public education and to the training of teachers for the imagined approaches to special education. The importance of imagining special and inclusive education being based on science and rationality and the limitations of proposed approaches to including students with disabilities in education are explained

    Phenylbutyric Acid Rescues Endoplasmic Reticulum Stress-Induced Suppression of APP Proteolysis and Prevents Apoptosis in Neuronal Cells

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    BACKGROUND: The familial and sporadic forms of Alzheimer's disease (AD) have an identical pathology with a severe disparity in the time of onset [1]. The pathological similarity suggests that epigenetic processes may phenocopy the Familial Alzheimer's disease (FAD) mutations within sporadic AD. Numerous groups have demonstrated that FAD mutations in presenilin result in 'loss of function' of gamma-secretase mediated APP cleavage [2], [3], [4], [5]. Accordingly, ER stress is prominent within the pathologically impacted brain regions in AD patients [6] and is reported to inhibit APP trafficking through the secretory pathway [7], [8]. As the maturation of APP and the cleaving secretases requires trafficking through the secretory pathway [9], [10], [11], we hypothesized that ER stress may block trafficking requisite for normal levels of APP cleavage and that the small molecular chaperone 4-phenylbutyrate (PBA) may rescue the proteolytic deficit. METHODOLOGY/PRINCIPAL FINDINGS: The APP-Gal4VP16/Gal4-reporter screen was stably incorporated into neuroblastoma cells in order to assay gamma-secretase mediated APP proteolysis under normal and pharmacologically induced ER stress conditions. Three unrelated pharmacological agents (tunicamycin, thapsigargin and brefeldin A) all repressed APP proteolysis in parallel with activation of unfolded protein response (UPR) signaling-a biochemical marker of ER stress. Co-treatment of the gamma-secretase reporter cells with PBA blocked the repressive effects of tunicamycin and thapsigargin upon APP proteolysis, UPR activation, and apoptosis. In unstressed cells, PBA stimulated gamma-secretase mediated cleavage of APP by 8-10 fold, in the absence of any significant effects upon amyloid production, by promoting APP trafficking through the secretory pathway and the stimulation of the non-pathogenic alpha/gamma-cleavage. CONCLUSIONS/SIGNIFICANCE: ER stress represses gamma-secretase mediated APP proteolysis, which replicates some of the proteolytic deficits associated with the FAD mutations. The small molecular chaperone PBA can reverse ER stress induced effects upon APP proteolysis, trafficking and cellular viability. Pharmaceutical agents, such as PBA, that stimulate alpha/gamma-cleavage of APP by modifying intracellular trafficking should be explored as AD therapeutics

    Liger for Next Generation Keck AO: Filter Wheel and Pupil Design

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    Liger is a next-generation near-infrared imager and integral field spectrograph (IFS) for the W.M. Keck Observatory designed to take advantage of the Keck All-Sky Precision Adaptive Optics (KAPA) upgrade. Liger will operate at spectral resolving powers between R\sim4,000 - 10,000 over a wavelength range of 0.8-2.4μ\mum. Liger takes advantage of a sequential imager and spectrograph design that allows for simultaneous observations between the two channels using the same filter wheel and cold pupil stop. We present the design for the filter wheels and pupil mask and their location and tolerances in the optical design. The filter mechanism is a multi-wheel design drawing from the heritage of the current Keck/OSIRIS imager single wheel design. The Liger multi-wheel configuration is designed to allow future upgrades to the number and range of filters throughout the life of the instrument. The pupil mechanism is designed to be similarly upgradeable with the option to add multiple pupil mask options. A smaller wheel mechanism allows the user to select the desired pupil mask with open slots being designed in for future upgrade capabilities. An ideal pupil would match the shape of the image formed of the primary and would track its rotation. For different pupil shapes without tracking we model the additional exposure time needed to achieve the same signal to noise of an ideal pupil and determine that a set of fixed masks of different shapes provides a mechanically simpler system with little compromise in performance.Comment: 9 pages, 7 figures, 1 tabl

    Liger for Next Generation Keck Adaptive Optics: Opto-Mechanical Dewar for Imaging Camera and Slicer

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    Liger is a next generation adaptive optics (AO) fed integral field spectrograph (IFS) and imager for the W. M. Keck Observatory. This new instrument is being designed to take advantage of the upgraded AO system provided by Keck All-Sky Precision Adaptive-optics (KAPA). Liger will provide higher spectral resolving power (R\sim4,000-10,000), wider wavelength coverage (\sim0.8-2.4 μ\mum), and larger fields of view than any current IFS. We present the design and analysis for a custom-made dewar chamber for characterizing the Liger opto-mechanical system. This dewar chamber is designed to test and assemble the Liger imaging camera and slicer IFS components while being adaptable for future experiments. The vacuum chamber will operate below 10510^{-5} Torr with a cold shield that will be kept below 90 K. The dewar test chamber will be mounted to an optical vibration isolation platform and further isolated from the cryogenic and vacuum systems with bellows. The cold head and vacuums will be mounted to a custom cart that will also house the electronics and computer that interface with the experiment. This test chamber will provide an efficient means of calibrating and characterizing the Liger instrument and performing future experiments.Comment: 8 pages, 6 figure

    Time-Resolved Infrared Spectroscopy Reveals the pH-Independence of the First Electron Transfer Step in the [FeFe] Hydrogenase Catalytic Cycle.

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    [FeFe] hydrogenases are highly active catalysts for hydrogen conversion. Their active site has two components: a [4Fe-4S] electron relay covalently attached to the H2 binding site and a diiron cluster ligated by CO, CN-, and 2-azapropane-1,3-dithiolate (ADT) ligands. Reduction of the [4Fe-4S] site was proposed to be coupled with protonation of one of its cysteine ligands. Here, we used time-resolved infrared (TRIR) spectroscopy on the [FeFe] hydrogenase from Chlamydomonas reinhardtii (CrHydA1) containing a propane-1,3-dithiolate (PDT) ligand instead of the native ADT ligand. The PDT modification does not affect the electron transfer step to [4Fe-4S]H but prevents the enzyme from proceeding further through the catalytic cycle. We show that the rate of the first electron transfer step is independent of the pH, supporting a simple electron transfer rather than a proton-coupled event. These results have important implications for our understanding of the catalytic mechanism of [FeFe] hydrogenases and highlight the utility of TRIR
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