994 research outputs found

    On the Use of a Magnetometer to Determine the Angular Motion of a Spinning Body in Regular Precession

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    Magnetometer for determination of angular motion of spinning body in regular precessio

    Economic and Policy Factors Driving the Adoption of Institutional Woody Biomass Heating Systems in the United States

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    New biomass combustion technologies and adequate biomass supplies have empowered the United States (U.S.) to look beyond satisfying heating needs with traditional fossil-based fuels, but biomass heating is often overlooked by many commercial and institutional entities. This study uses county level Zero Inflated Negative Binomial (ZINB) cross sectional regression analyses to identify economic factors that are favorable to the adoption of decentralized woody biomass heating systems by institutions in the U.S. In addition, biomass policy efficacy with respect to decentralized biomass heating systems is analyzed and regression results are used to develop an expansion map that highlights counties in the U.S. that may be good targets for biomass heating. Across all three models higher heating degree days, population density, and available forest residues decrease the odds of a county not containing an institution using a decentralized biomass heating system, with forest residues being the best predictor. When predicting the likely count of institutions using biomass heating systems, heating degree days, commercial natural gas prices, median house value, available biomass from lands treated under the National Fire Plan, and the proportion of Forest Service land have statistically significant coefficients that are positive. An increase in each of these variables is positively associated with an increased likelihood of one or more institutions using biomass. State policies in support of biomass use were shown to have a negligible effect on the number of decentralized biomass heating systems, while procurement policies related to utility infrastructure and renewable products and fuels specifically have a negative association. It is worth noting that, though level of active management resulting in biomass production is not a policy variable per se, it has important policy dimensions. Both federal land management practices and resources allocated to fuel treatments under NFP are highly subject to public policy decisions, including budget allocations for forest restoration and fuels treatments. Future expansion in the use of decentralized biomass heating systems is predicted to be most successful in counties in the Northwest and Northeast, and to a lesser degree in counties in the states of Michigan, Colorado, and New Mexico

    Producing High Concentrations of Hydrogen in Palladium via Electrochemical Insertion from Aqueous and Solid Electrolytes

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    Metal hydrides are critical materials in numerous technologies including hydrogen storage, gas separation, and electrocatalysis. Here, using Pd-H as a model metal hydride, we perform electrochemical insertion studies of hydrogen via liquid and solid state electrolytes at 1 atm ambient pressure, and achieve H:Pd ratios near unity, the theoretical solubility limit. We show that the compositions achieved result from a dynamic balance between the rate of hydrogen insertion and evolution from the Pd lattice, the combined kinetics of which are sufficiently rapid that operando experiments are necessary to characterize instantaneous PdHx composition. We use simultaneous electrochemical insertion and X-ray diffraction measurements, combined with a new calibration of lattice parameter versus hydrogen concentration, to enable accurate quantification of the composition of electrochemically synthesized PdHx. Furthermore, we show that the achievable hydrogen concentration is severely limited by electrochemomechanical damage to the palladium and/or substrate. The understanding embodied in these results helps to establish new design rules for achieving high hydrogen concentrations in metal hydrides.Comment: 38 page

    Early primary care physician contact and health service utilisation in a large sample of recently released ex-prisoners in Australia: Prospective cohort study

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    Objective: To describe the association between ex-prisoner primary care physician contact within 1 month of prison release and health service utilisation in the 6 months following release. Design: A cohort from the Passports study with a mean follow-up of 219 (±44) days postrelease. Associations were assessed using a multivariate Andersen-Gill model, controlling for a range of other factors. Setting: Face-to-face, baseline interviews were conducted in a sample of prisoners within 6 weeks of expected release from seven prisons in Queensland, Australia, from 2008 to 2010, with telephone follow-up interviews 1, 3 and 6 months postrelease. Participants: From an original population-based sample of 1325 sentenced adult (≥18 years) prisoners, 478 participants were excluded due to not being released from prison during follow-up (n=7, 0.5%), loss to follow-up (n=257, 19.4%), or lacking exposure data (n=214, 16.2%). A total of 847 (63.9%) participants were included in the analyses. Exposure: Primary care physician contact within 1 month of follow-up as a dichotomous measure. Main outcome measures: Adjusted time-to-event hazard rates for hospital, mental health, alcohol and other drug and subsequent primary care physician service utilisations assessed as multiple failure time-interval data. Results: Primary care physician contact prevalence within 1 month of follow-up was 46.5%. One-month primary care physician contact was positively associated with hospital (adjusted HR (AHR)=2.07; 95% CI 1.39 to 3.09), mental health (AHR=1.65; 95% CI 1.24 to 2.19), alcohol and other drug (AHR=1.48; 95% CI 1.15 to 1.90) and subsequent primary care physician service utilisation (AHR=1.47; 95% CI 1.26 to 1.72) over 6 months of follow-up. Conclusions: Engagement with primary care physician services soon after prison release increases health service utilisation during the critical community transition period for ex-prisoners

    Analytical Method of Approximating the Motion of a Spinning Vehicle with Variable Mass and Inertia Properties Acted Upon by Several Disturbing Parameters

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    An analytical method has been developed which approximates the dispersion of a spinning symmetrical body in a vacuum, with time-varying mass and inertia characteristics, under the action of several external disturbances-initial pitching rate, thrust misalignment, and dynamic unbalance. The ratio of the roll inertia to the pitch or yaw inertia is assumed constant. Spin was found to be very effective in reducing the dispersion due to an initial pitch rate or thrust misalignment, but was completely Ineffective in reducing the dispersion of a dynamically unbalanced body

    Modeling 5 Years of Subglacial Lake Activity in the MacAyeal Ice Stream (Antarctica) Catchment Through Assimilation of ICESat Laser Altimetry

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    Subglacial lakes beneath Antarctica’s fast-moving ice streams are known to undergo ~1km3 volume changes on annual timescales. Focusing on the MacAyeal Ice Stream (MacIS) lake system, we create a simple model for the response of subglacial water distribution to lake discharge events through assimilation of lake volume changes estimated from Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry. We construct a steady-state water transport model in which known subglacial lakes are treated as either sinks or sources depending on the ICESat-derived filling or drainingrates. The modeled volume change rates of five large subglacial lakes in the downstream portion of MacIS are shown to be consistent with observed filling rates if the dynamics of all upstream lakes are considered. However, the variable filling rate of the northernmost lake suggests the presence of an undetected lake of similar size upstream. Overall, we show that, for this fast-flowing ice stream, most subglacial lakes receive \u3e90% of their water from distant distributed sources throughout the catchment, and we confirm that water is transported from regions of net basal melt to regions of net basal freezing. Our study provides a geophysically based means of validating subglacial water models in Antarctica and is a potential way to parameterize subglacial lake discharge events in large-scale ice-sheet models where adequate data are available

    The RCSB Protein Data Bank: views of structural biology for basic and applied research and education.

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    The RCSB Protein Data Bank (RCSB PDB, http://www.rcsb.org) provides access to 3D structures of biological macromolecules and is one of the leading resources in biology and biomedicine worldwide. Our efforts over the past 2 years focused on enabling a deeper understanding of structural biology and providing new structural views of biology that support both basic and applied research and education. Herein, we describe recently introduced data annotations including integration with external biological resources, such as gene and drug databases, new visualization tools and improved support for the mobile web. We also describe access to data files, web services and open access software components to enable software developers to more effectively mine the PDB archive and related annotations. Our efforts are aimed at expanding the role of 3D structure in understanding biology and medicine

    Phage-Encoded Cationic Antimicrobial Peptide Required for Lysis

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    Abstract: Most phages of Gram-negative bacteria hosts encode spanins for disruption of the outer membrane, which is the last step in host lysis. However, bioinformatic analysis indicates that ∼15% of these phages lack a spanin gene, suggesting they have an alternate way of disrupting the outer membrane (OM). Here, we show that the T7-like coliphage phiKT causes an explosive cell lysis associated with spanin activity despite not encoding spanins. A putative lysis cassette cloned from the phiKT late gene region includes the hypothetical novel gene 28 located between the holin and endolysin genes and supports inducible lysis in Escherichia coli K-12. Moreover, induction of an isogenic construct lacking gene 28 resulted in divalent cation-stabilized spherical cells rather than lysis, implicating gp28 in OM disruption. Additionally, gp28 was shown to complement the lysis defect of a spanin-null λ lysogen. Gene 28 encodes a 56-amino acid cationic protein with predicted amphipathic helical structure and is membrane-associated after lysis. Urea and KCl washes did not release gp28 from the particulate, suggesting a strong hydrophobic membrane interaction. Fluorescence microscopy supports membrane localization of the gp28 protein before lysis. The protein gp28 is similar in size, charge, predicted fold, and membrane association to the human cathelicidin antimicrobial peptide LL-37. Synthesized gp28 behaved similarly to LL-37 in standard assays mixing peptide and cells to measure bactericidal and inhibitory effects. Taken together, these results indicate that phiKT gp28 is a phage-encoded cationic antimicrobial peptide that disrupts bacterial outer membranes during host lysis and, thus, establishes a new class of phage lysis proteins, the disruptins. Importance: We provide evidence that phiKT produces an antimicrobial peptide for outer membrane disruption during lysis. This protein, designated a disruptin, is a new paradigm for phage lysis and has no similarities to other known lysis genes. Although many mechanisms have been proposed for the function of antimicrobial peptides, there is no consensus on the molecular basis of membrane disruption. Additionally, there is no established genetic system to support such studies. Therefore, the phiKT disruptin may represent the first genetically tractable antimicrobial peptide, facilitating mechanistic analyses
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