3,512 research outputs found

    A snake of a different color: physiological color change in Arizona black rattlesnakes

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    Coloration may serve a variety of behavioral (e.g., crypsis, communication) and physiological (e.g., thermoregulation, protection) functions for terrestrial ectotherms. However, optimal coloration for a given function may vary over environments (spatial or temporal) or conflict with other functions. Physiological color change (rapid change due to movement of pigment granules within chromatophores) may be an adaptation to resolve conflicting selective pressures on coloration. The proximate factors related to physiological color change are well known in many animals, but few studies have investigated the ecological or evolutionary implications of this behavior. Here, we present alternative hypotheses for physiological color change and discuss biotic and abiotic factors that may have led to the maintenance and/or loss of this behavior among populations of Arizona black rattlesnakes (_Crotalus cerberus_). We discuss what is known about this behavior and propose to investigate the function and evolution of coloration and color change in _C. cerberus_

    Optimizing the integration of advanced practitioners in a department of surgery: An operational improvement model

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    Physician assistants (PAs) and nurse practitioners (NPs) have established themselves as key members of the healthcare team to supplement practicing physicians in patient care. PAs and NPs are collectively referred to as “advanced providers” (APs) and work not only in primary care but in general surgery and surgical subspecialties. Studies have addressed AP integration into the profession of medicine and have examined cost and efficacy of APs, attitudes about APs among residents, and educational impact of APs, but very little literature exists that describes a formalized approach to AP integration into a department of surgery, specifically with AP/resident integration. The purpose of this paper is to describe an initiative for developing an operational improvement model for APs working with residents on surgical inpatient services in a large academic health center. The model consists of four components and each component is described in detail from discovery state towards continuous improvement. Formal professional development opportunities for APs as well as appointing a Clinical Director for Surgical APs have positively impacted AP integration into the department of surgery

    Teacher Allies: An Exploration of the Professional Experiences of Teachers Who Support LGBTQ Students

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    This dissertation is a year-long qualitative exploration of the experiences and perspectives of classroom teachers who identify as allies or supporters for lesbian, gay, bisexual, transgender, queer and questioning (LGBTQ) public school students. Nine teachers representing five secondary schools in Central New York participated in three semi-structured interviews and approximately fifteen hours of classroom observation. Questions driving this research focused on (1) how teacher allies make meaning of LGBTQ students\u27 needs and their roles in addressing those needs; (2) how participants integrate ally work into the larger context of their professional practice; and (3) participants\u27 management of stigma or resistance around their ally work. Findings illuminate how educators engage in the work of supporting LGBTQ students without directly speaking about or acknowledging how gender and sexuality are relevant to experiences of teaching and learning. Educators instead framed the needs of LGBTQ students and the possibilities for improving their school experiences within broader frameworks of supporting diversity, teaching tolerance, safe schools, and anti-bullying. It will be argued that these frameworks provide rhetorical and instructional tools for talking about and implementing strategies that aim to encompass the needs of all students but do not require educators to consider how or why heterosexual, gender conforming identities are privileged and LGBTQ identities are marginalized in school environments

    Step Model for Managing Chronic, Non-Malignant Pain in Primary Care

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    Oftentimes, primary care providers lack the knowledge, confidence, and time to monitor chronic pain patients closely resulting in possible inappropriate prescribing of opioids. Purpose: The project aim was to improve primary care provider knowledge and confidence in managing chronic pain patients in the primary care setting using a step model that was developed based on the Centers for Disease Control (CDC) guidelines as well as online education modules produced by the CDC. Methods: The project design was a quantitative pretest-posttest design. The primary outcome was to provide training on the CDC guidelines for prescribing opioids for chronic pain as well as implementation of a step model for primary care providers increasing their knowledge and confidence in management of chronic, non-malignant (CNMP) pain patients. Outcomes and Results: There were seven questions on the pre- and posttest that were analyzed using Wilcoxon Signed Ranks Test. Of the seven questions, five were statistically significant. The project data showed that the education module and step model increased knowledge and confidence in managing CNMP and prescribing opioid medication for this population (n=7). It also demonstrated a lack of education related to management of CNMP and opioid medications highlighting the need for increased education on chronic pain management and opioid therapy for physicians in the sample population as evidenced by statistically significant improvement between the pretest and posttest scores

    First Amendment and Private Property: A Sign for Free Speech, The

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    Freedom of speech is one of the best known of all the constitutional rights protected by the Bill of Rights. Freedom of speech has received special attention from the courts for at least three reasons: (1) it is essential to the political process that is the foundation of our democracy;3 (2) it is fundamentally important to the discovery of truth in the free marketplace of ideas;4 and (3) it is an end in itself in a free country. In furtherance of a substantial interest, however, the freedom of speech falls subject to the police power of the state. In City of Ladue v. Gilleo, the Court was confronted with the task of balancing two competing interests: (1) the well-established authority of the State to regulate in furtherance of an aesthetic purpose; and (2) the right of a citizen to express her private political viewpoints while on her private property

    Discovery of Sex-Specific Regions in a Salamander Genome

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    Biological Aspects: Salamander (Ambystoma mexicanum) has a gigantic genome: ~32,000,000,000 bases (10X of size of human genome) Sex is determined by a pair of morphologically identical chromosomes: ZZ in male ZW in female Object: Find (if there are any) genomic differences between chromosomes W and Z Workflow: Sequencing and de novo assembly of the reference salamander genome Alignment of short sequences from male and female genomes to the reference Coverage analysi

    Path-specific causal decomposition analysis with multiple correlated mediator variables

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    A causal decomposition analysis allows researchers to determine whether the difference in a health outcome between two groups can be attributed to a difference in each group's distribution of one or more modifiable mediator variables. With this knowledge, researchers and policymakers can focus on designing interventions that target these mediator variables. Existing methods for causal decomposition analysis either focus on one mediator variable or assume that each mediator variable is conditionally independent given the group label and the mediator-outcome confounders. In this paper, we propose a flexible causal decomposition analysis method that can accommodate multiple correlated and interacting mediator variables, which are frequently seen in studies of health behaviors and studies of environmental pollutants. We extend a Monte Carlo-based causal decomposition analysis method to this setting by using a multivariate mediator model that can accommodate any combination of binary and continuous mediator variables. Furthermore, we state the causal assumptions needed to identify both joint and path-specific decomposition effects through each mediator variable. To illustrate the reduction in bias and confidence interval width of the decomposition effects under our proposed method, we perform a simulation study. We also apply our approach to examine whether differences in smoking status and dietary inflammation score explain any of the Black-White differences in incident diabetes using data from a national cohort study

    Diffusion Tensor Imaging Predictors of Episodic Memory Decline in Healthy Elders at Genetic Risk for Alzheimer’s Disease

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    Objectives: White matter (WM) integrity within the mesial temporal lobe (MTL) is important for episodic memory (EM) functioning. The current study investigated the ability of diffusion tensor imaging (DTI) in MTL WM tracts to predict 3-year changes in EM performance in healthy elders at disproportionately higher genetic risk for Alzheimer’s disease (AD). Methods: Fifty-one cognitively intact elders (52% with family history (FH) of dementia and 33% possessing an Apolipoprotein E ε4 allelle) were administered the Rey Auditory Verbal Learning Test (RAVLT) at study entry and at 3-year follow-up. DTI scanning, conducted at study entry, examined fractional anisotropy and mean, radial and axial diffusion within three MTL WM tracts: uncinate fasciculus (UNC), cingulate-hippocampal (CHG), and fornix-stria terminalis (FxS). Correlations were performed between residualized change scores computed from RAVLT trials 1–5, immediate recall, and delayed recall scores and baseline DTI measures; MTL gray matter (GM) and WM volumes; demographics; and AD genetic and metabolic risk factors. Results: Higher MTL mean and axial diffusivity at baseline significantly predicted 3-year changes in EM, whereas baseline MTL GM and WM volumes, FH, and metabolic risk factors did not. Both ε4 status and DTI correlated with change in immediate recall. Conclusions: Longitudinal EM changes in cognitively intact, healthy elders can be predicted by disruption of the MTL WM microstructure. These results are derived from a sample with a disproportionately higher genetic risk for AD, suggesting that the observed WM disruption in MTL pathways may be related to early neuropathological changes associated with the preclinical stage of AD. (JINS, 2016, 22, 1005–1015

    Interactive Effects of Physical Activity and APOE-ε4 On White Matter Tract Diffusivity in Healthy Elders

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    Older adult apolipoprotein-E epsilon 4 (APOE-ε4) allele carriers vary considerably in the expression of clinical symptoms of Alzheimer\u27s disease (AD), suggesting that lifestyle or other factors may offer protection from AD-related neurodegeneration. We recently reported that physically active APOE-ε4 allele carriers exhibit a stable cognitive trajectory and protection from hippocampal atrophy over 18 months compared to sedentary ε4 allele carriers. The aim of this study was to examine the interactions between genetic risk for AD and physical activity (PA) on white matter (WM) tract integrity, using diffusion tensor imaging (DTI) MRI, in this cohort of healthy older adults (ages of 65 to 89). Four groups were compared based on the presence or absence of an APOE-ε4 allele (High Risk; Low Risk) and self-reported frequency and intensity of leisure time physical activity (PA) (High PA; Low PA). As predicted, greater levels of PA were associated with greater fractional anisotropy (FA) and lower radial diffusivity in healthy older adults who did not possess the APOE-ε4 allele. However, the effects of PA were reversed in older adults who were at increased genetic risk for AD, resulting in significant interactions between PA and genetic risk in several WM tracts. In the High Risk-Low PA participants, who had exhibited episodic memory decline over the previous 18-months, radial diffusivity was lower and fractional anisotropy was higher, compared to the High Risk-High PA participants. In WM tracts that subserve learning and memory processes, radial diffusivity (DR) was negatively correlated with episodic memory performance in physically inactive APOE-ε4 carriers, whereas DR was positively correlated with episodic memory performance in physically active APOE-ε4 carriers and the two Low Risk groups. The common model of demyelination-induced increase in radial diffusivity cannot directly explain these results. Rather, we hypothesize that PA may protect APOE-ε4 allele carriers from selective neurodegeneration of individual fiber populations at locations of crossing fibers within projection and association WM fiber tracts

    Using Physiologically-Based Pharmacokinetic Models to Incorporate Chemical and Non-Chemical Stressors into Cumulative Risk Assessment: A Case Study of Pesticide Exposures

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    Cumulative risk assessment has been proposed as an approach to evaluate the health risks associated with simultaneous exposure to multiple chemical and non-chemical stressors. Physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) models can allow for the inclusion and evaluation of multiple stressors, including non-chemical stressors, but studies have not leveraged PBPK/PD models to jointly consider these disparate exposures in a cumulative risk context. In this study, we focused on exposures to organophosphate (OP) pesticides for children in urban low-income environments, where these children would be simultaneously exposed to other pesticides (including pyrethroids) and non-chemical stressors that may modify the effects of these exposures (including diet). We developed a methodological framework to evaluate chemical and non-chemical stressor impacts on OPs, utilizing an existing PBPK/PD model for chlorpyrifos. We evaluated population-specific stressors that would influence OP doses or acetylcholinesterase (AChE) inhibition, the relevant PD outcome. We incorporated the impact of simultaneous exposure to pyrethroids and dietary factors on OP dose through the compartments of metabolism and PD outcome within the PBPK model, and simulated combinations of stressors across multiple exposure ranges and potential body weights. Our analyses demonstrated that both chemical and non-chemical stressors can influence the health implications of OP exposures, with up to 5-fold variability in AChE inhibition across combinations of stressor values for a given OP dose. We demonstrate an approach for modeling OP risks in the presence of other population-specific environmental stressors, providing insight about co-exposures and variability factors that most impact OP health risks and contribute to children’s cumulative health risk from pesticides. More generally, this framework can be used to inform cumulative risk assessment for any compound impacted by chemical and non-chemical stressors through metabolism or PD outcomes
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