Nonparametric Bounds and Sensitivity Analysis of Treatment Effects

This paper considers conducting inference about the effect of a treatment (or exposure) on an outcome of interest. In the ideal setting where treatment is assigned randomly, under certain assumptions the treatment effect is identifiable from the observable data and inference is straightforward. However, in other settings such as observational studies or randomized trials with noncompliance, the treatment effect is no longer identifiable without relying on untestable assumptions. Nonetheless, the observable data often do provide some information about the effect of treatment, that is, the parameter of interest is partially identifiable. Two approaches are often employed in this setting: (i) bounds are derived for the treatment effect under minimal assumptions, or (ii) additional untestable assumptions are invoked that render the treatment effect identifiable and then sensitivity analysis is conducted to assess how inference about the treatment effect changes as the untestable assumptions are varied. Approaches (i) and (ii) are considered in various settings, including assessing principal strata effects, direct and indirect effects and effects of time-varying exposures. Methods for drawing formal inference about partially identified parameters are also discussed.Comment: Published in at http://dx.doi.org/10.1214/14-STS499 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

The Influence of Easing COVID-19 Restrictions on the Physical Activity Intentions and Perceived Barriers to Physical Activity in UK Older Adults

COVID-19 has had profound effects on physical activity behaviours of older adults, and understanding this impact is essential to driving public health policies to promote healthy ageing. The present study aimed to determine; (1) intended physical activity behaviours of older adults following the easing of UK COVID-19 restrictions; (2) the relationship between self-reported physical activity and intended physical activity behaviour; (3) perceived barriers to achieving the intended physical activity goal. Ninety-six participants (74.8 ± 4.4 years; 52 female) from a longitudinal study examining the impact of COVID-19 on physical activity were recruited. Participants outlined their future physical activity intentions and completed the COM-B Self Evaluation Questionnaire. Participants were split into groups based on their intention to ‘Maintain’ (n = 29), ‘Increase’ (n = 38) or ‘Return’ (n = 29) to pre-COVID-19 physical activity. Self-reported physical activity undulated over the pandemic but was mostly equivalent between groups. Intended physical activity behaviour was independent of self-report physical activity. Capability and motivation factors were the most frequently cited barriers to the intended physical activity behaviour, with a greater number of capability barriers in the ‘Return’ group. Such barriers should be considered in the COVID-19 recovery public health physical activity strategy for promoting healthy ageing

Factors Influencing Pika Foraging Behavior in the North Cascades National Park Service Complex, Washington

The American pika (Ochotona princeps) is a small lagomorph restricted to talus slopes at higher elevations or latitudes throughout mountainous regions in western North America. Pikas respond to seasonal fluctuations in food availability by haying, i.e., storing, vegetation for use during winter, and are considered a climate change indicator species because of their sensitivity to heat and restricted habitat requirements. Prior to 2009, no data existed on pika populations or foraging behavior in the North Cascades National Park Service Complex (NOCA) in Washington. To help address these data needs, we collected behavioral data on 95 foraging pikas throughout NOCA during summer 2009 and 2010 to better understand abiotic and biotic factors affecting foraging behavior and potential impacts of climate change on pikas. We calculated the proportion of time pikas spent grazing and haying, and developed competing hypotheses for each behavior expressed as logistic regression models consisting of climate, vegetation, elevation, date, and year covariates. We selected top models for both behaviors using information-theoretic techniques, and found that time spent grazing decreased while haying behavior increased through summer. Pikas spent more time haying as elevation increased while time spent grazing was negatively correlated with elevation, suggesting possible constraints in time available for foraging at higher elevations. Time spent grazing was also negatively correlated with temperature, a result likely in response to thermoregulation limitations of pikas. These results demonstrate how multiple factors may affect pika foraging behavior, thereby providing an opportunity to assist resource managers in future decisions regarding pika conservation

Youth multilingualism and discourses of disability: An intersectional approach

Magister Artium - MADisability, as a topic of investigation, is considerably overlooked in the discipline of sociolinguistics. This thesis aims to bridge the gap between disability and sociolinguistics studies, as I critically explore the role language and multilingualism plays in the way we understand and construct the discourses of disability. Based on a year-long ethnographic study at what is defined as a “special needs school”, I offer a first-hand description of being a researcher with a disability through personal anecdotes. In these anecdotes, I account for my own positionality to highlight the importance of reflectivity and positionality when doing ethnographic fieldwork. Aside from these personal anecdotes, I also capture everyday interactions among young disabled people. In order to analyse these disabled youth multilingual interactions, I applied the notions of stylization, enregisterment and embodied intersectionality. In these examinations, we are able to see how multilingualism is used to negotiate a position of being seen as disabled. By looking at these personal anecdotes and everyday interactions as whole, the study provides a more comprehensive view of the way we talk and represent disability. I conclude this thesis by offering a new direction for disability and youth multilingualism studies, a direction that emphasises the importance of positionality when doing research on the agency of disabled people

Prevailing Academic View on Compliance Flexibility under § 111 of the Clean Air Act

No colons in abstractsource category, existing sources, state implementation plan, new sources, tradable performance standards

Improved chemistry restraints for crystallographic refinement by integrating the Amber force field into Phenix.

The refinement of biomolecular crystallographic models relies on geometric restraints to help to address the paucity of experimental data typical in these experiments. Limitations in these restraints can degrade the quality of the resulting atomic models. Here, an integration of the full all-atom Amber molecular-dynamics force field into Phenix crystallographic refinement is presented, which enables more complete modeling of biomolecular chemistry. The advantages of the force field include a carefully derived set of torsion-angle potentials, an extensive and flexible set of atom types, Lennard-Jones treatment of nonbonded interactions and a full treatment of crystalline electrostatics. The new combined method was tested against conventional geometry restraints for over 22 000 protein structures. Structures refined with the new method show substantially improved model quality. On average, Ramachandran and rotamer scores are somewhat better, clashscores and MolProbity scores are significantly improved, and the modeling of electrostatics leads to structures that exhibit more, and more correct, hydrogen bonds than those refined using traditional geometry restraints. In general it is found that model improvements are greatest at lower resolutions, prompting plans to add the Amber target function to real-space refinement for use in electron cryo-microscopy. This work opens the door to the future development of more advanced applications such as Amber-based ensemble refinement, quantum-mechanical representation of active sites and improved geometric restraints for simulated annealing

Modeling And Experimental Determination Of Physical Properties Of Ge x -Ga y -Se 1-x-y Chalcogenide Glasses I: Structure And Mechanical Properties

A series of ten GexGaySe1-x-y glasses within the topological constraint regime of = 2.3 to 2.8 were processed for physical property testing to compare measured to calculated property values enabling further understanding of structure-related mechanical property evolution. Average bond energies were calculated for each glass to elucidate structure and property relationships. Raman analysis was performed to correlate the topological constraint theory to experimentally determined structural units. Young\u27s modulus and Vickers hardness, respectively, were shown to increase with increasing coordination number from 14.42 GPa and 911 MPa at = 2.4 to 29.44 GPa and 2295 MPa at = 2.8. Poisson\u27s ratio decreased linearly with increasing coordination number from 0.2996 at = 2.4 for Ge0.15Ga0.05Se0.85 to 0.2477 at = 2.8 for Ge0.25Ga0.15Se0.60 . These properties indicate a strong dependence on the topological network of the glass, in which continued crosslinking and interconnectivity lead to a direct increase or decrease of the respective mechanical property. It was found that theoretical values were in good agreement with measured experiment values, elucidating the impact of the energy required to propagate a crack tip or alter bond lengths and atom positions

Microglia in aging and Alzheimer’s disease: A comparative species review

Microglia are the primary immune cells of the central nervous system that help nourish and support neurons, clear debris, and respond to foreign stimuli. Greatly impacted by their environment, microglia go through rapid changes in cell shape, gene expression, and functional behavior during states of infection, trauma, and neurodegeneration. Aging also has a profound effect on microglia, leading to chronic inflammation and an increase in the brain’s susceptibility to neurodegenerative processes that occur in Alzheimer’s disease. Despite the scientific community’s growing knowledge in the field of neuroinflammation, the overall success rate of drug treatment for age-related and neurodegenerative diseases remains incredibly low. Potential reasons for the lack of translation from animal models to the clinic include the use of a single species model, an assumption of similarity in humans, and ignoring contradictory data or information from other species. To aid in the selection of validated and predictive animal models and to bridge the translational gap, this review evaluates similarities and differences among species in microglial activation and density, morphology and phenotype, cytokine expression, phagocytosis, and production of oxidative species in aging and Alzheimer’s disease

NCRC 2020 Home Mortgage Report: Examining Shifts During COVID-19

In this report:The private mortgage lending market continued to inadequately serve most households of color.The gap in homeownership rates between Black and White families remained near a 120-year high point.Refinance lending exploded during the pandemic and disproportionately flowed to non-Hispanic White, Asian Indian and Chinese borrowers.Over decades, the private mortgage market and laws intended to expand access to credit have failed to achieve equitable home ownership rates or increase family wealth in communities of color.Policy makers, community leaders and lenders themselves should rally around bold new approaches, race-specific goals and performance requirements