5,251 research outputs found

    Toward a descriptive model of galactic cosmic rays in the heliosphere

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    Researchers review the elements that enter into phenomenological models of the composition, energy spectra, and the spatial and temporal variations of galactic cosmic rays, including the so-called anomalous cosmic ray component. Starting from an existing model, designed to describe the behavior of cosmic rays in the near-Earth environment, researchers suggest possible updates and improvements to this model, and then propose a quantitative approach for extending such a model into other regions of the heliosphere

    Growth and Nutritional Quality of Lemnaceae Viewed Comparatively in an Ecological and Evolutionary Context

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    This review focuses on recently characterized traits of the aquatic floating plant Lemna with an emphasis on its capacity to combine rapid growth with the accumulation of high levels of the essential human micronutrient zeaxanthin due to an unusual pigment composition not seen in other fast-growing plants. In addition, Lemna’s response to elevated CO2 was evaluated in the context of the source–sink balance between plant sugar production and consumption. These and other traits of Lemnaceae are compared with those of other floating aquatic plants as well as terrestrial plants adapted to different environments. It was concluded that the unique features of aquatic plants reflect adaptations to the freshwater environment, including rapid growth, high productivity, and exceptionally strong accumulation of high-quality vegetative storage protein and human antioxidant micronutrients. It was further concluded that the insensitivity of growth rate to environmental conditions and plant source–sink imbalance may allow duckweeds to take advantage of elevated atmospheric CO2 levels via particularly strong stimulation of biomass production and only minor declines in the growth of new tissue. It is proposed that declines in nutritional quality under elevated CO2 (due to regulatory adjustments in photosynthetic metabolism) may be mitigated by plant–microbe interaction, for which duckweeds have a high propensity.This work was funded by the Translational Research Institute for Space Health through Cooperative Agreement NNX16AO69A, the National Science Foundation award number IOS-1907338, and the University of Colorado

    Automated ligand fitting by core-fragment fitting and extension into density

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    An automated ligand-fitting procedure has been developed and tested on 9327 ligands and (F o − F c)exp(iϕc) difference density from macromolecular structures in the Protein Data Bank

    A Survey of Employee Perceptions of Information Privacy in Organizations

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    In this study of employees in five multinational corporations, assessment was made of (a) employees\u27 beliefs regarding the types of personal information stored their companies, (b) the accuracy of those perceptions, (c) reactions to various internal and external uses of this personal information, and (d) evaluations of the companies\u27 information handling policies and practices

    Detecting Discrimination in Small Business Lending

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    With limited financial sophistication, entrepreneurial consumers approach the financial marketplace more like retail financial consumers than business customers. However, the assumption of both legislators and regulators is that business-borrowers are more financially savvy than consumer-borrowers, and thus do not require as broad-reaching protections. This gap between marketplace policy protections and the lived reality of the vast majority of small business entrepreneurs sets the stage for entrepreneurial consumers to fall through the regulatory cracks and sets the stage for possible exploitation and abuse. This situation is potentially exacerbated for minority entrepreneurs who belong to protected classes that are generally more vulnerable to exploitation in the marketplace including the small business lending marketplace. In this paper, we highlight the current state of this policy gap in the marketplace relative to minority entrepreneurial consumers and present a matched-paired mystery shopping study that demonstrates the critical need for reliable, primary data to inform regulatory agencies as they work to implement available protections to ensure equal access to credit within the small business lending marketplace

    Hydrophobic residues at position 10 of α-conotoxin PnIA influence subtype selectivity between α7 and α3β2 neuronal nicotinic acetylcholine receptors

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    Neuronal nicotinic acetylcholine receptors (nAChRs) are a diverse class of ligand-gated ion channels involved in neurological conditions such as neuropathic pain and Alzheimer's disease. α-Conotoxin [A10L]PnIA is a potent and selective antagonist of the mammalian α7 nAChR with a key binding interaction at position 10. We now describe a molecular analysis of the receptor-ligand interactions that determine the role of position 10 in determining potency and selectivity for the α7 and α3β2 nAChR subtypes. Using electrophysiological and radioligand binding methods on a suite of [A10L]PnIA analogs we observed that hydrophobic residues in position 10 maintained potency at both subtypes whereas charged or polar residues abolished α7 binding. Molecular docking revealed dominant hydrophobic interactions with several α7 and α3β2 receptor residues via a hydrophobic funnel. Incorporation of norleucine (Nle) caused the largest (8-fold) increase in affinity for the α7 subtype (Ki = 44 nM) though selectivity reverted to α3β2 (IC50 = 0.7 nM). It appears that the placement of a single methyl group determines selectivity between α7 and α3β2 nAChRs via different molecular determinants

    Minimum Information about a Neuroscience Investigation (MINI) Electrophysiology

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    This module represents the formalized opinion of the authors and the CARMEN consortium, which identifies the minimum information required to report the use of electrophysiology in a neuroscience study, for submission to the CARMEN system (www.carmen.org.uk).
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