5,715 research outputs found
Analysis of cell performance and thermal regeneration of a lithium-tin cell having an immobilized fused-salt electrolyte
Cell performance and thermal regeneration of a thermally regenerative cell uses lithium and tin and a fused-salt electrolyte. The emf of the Li-Sn cell, as a function of cathode-alloy composition, is shown to resemble that of the Na-Bi cell
Analysis of secondary cells with lithium anodes and immobilized fused-salt electrolytes
Secondary cells with liquid lithium anodes, liquid bismuth or tellurium cathodes, and fused lithium halide electrolytes immobilized as rigid pastes operate between 380 and 485 degrees. Applications include power sources in space, military vehicle propulsion and special commercial vehicle propulsion
Area-level socioeconomic disadvantage and suicidal behaviour in Europe: a systematic review
The relationship between adverse individual socio-economic circumstances and suicidal behaviour is well established. However, the impact of adverse collective circumstances - such as the socio-economic context where people live - is less well understood.
This systematic review explores the extent to which area-level socioeconomic disadvantage is associated with inequalities in suicidal behaviour and self-harm in Europe. We performed a systematic review (in MEDLINE, Embase, PsycINFO, EconLit and Social Sciences Citation Index) from 2005 to 2015. Observational studies were included if they were based in Europe and had a primary suicidal behaviour and self-harm outcome, compared at least two areas, included an area-level measure of socio-economic disadvantage and were published in the English language.
The review followed The Joanna Briggs Institute guidelines for quality appraisal. We identified 27 studies (30 papers) from 14 different European countries. There was a significant association (in 25/27 studies, all of which were rated as of medium or high quality) between socioeconomic disadvantage and suicidal behaviour (and self-harm), particularly for men, and this was a consistent finding across a variety of European countries. Socio-economic disadvantage was found to have an independent effect in several studies whilst others found evidence of mediating contextual and compositional factors. There is strong evidence of an association between suicidal behaviours (and self-harm) and area-level socio-economic disadvantage in Europe, particularly for men. Suicide prevention strategies should take this into account.
Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over time
BACKGROUND How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large cohort study of middle-aged UK women. METHODS At recruitment, Million Women Study participants completed a baseline questionnaire including questions on frequency of strenuous and of any physical activity. About 3 years later 589,896 women also completed a follow-up questionnaire reporting the hours they spent on a range of specific activities. Time spent on each activity was used to estimate the associated excess metabolic equivalent hours (MET-hours) and this value was compared across categories of physical activity reported at recruitment. Additionally, 18,655 women completed the baseline questionnaire twice, at intervals of up to 4 years; repeatability over time was assessed using the weighted kappa coefficient (κweighted) and absolute percentage agreement. RESULTS The average number of hours per week women reported doing specific activities was 14.0 for housework, 4.5 for walking, 3.0 for gardening, 0.2 for cycling, and 1.4 for all strenuous activity. Time spent and the estimated excess MET-hours associated with each activity increased with increasing frequency of any or strenuous physical activity reported at baseline (tests for trend, P < 0.003), although the associations for housework were by far the weakest (Spearman correlations, 0.01 and -0.03 respectively for housework, and 0.11-0.37 for all other activities). Repeatability of responses to physical activity questions on the baseline questionnaire declined significantly over time. For strenuous activity, absolute agreement was 64% (κweighted = 0.71) for questionnaires administered less than 6 months apart, and 52% (κweighted = 0.51) for questionnaires more than 2 years apart. Corresponding values for any physical activity were 57% (κweighted = 0.67) and 47% (κweighted = 0.58). CONCLUSIONS In this cohort, responses to simple questions on the frequency of any physical activity and of strenuous activity asked at baseline were associated with hours spent on specific activities and the associated estimated excess MET-hours expended, reported 3 years later. The weakest associations were with housework. Agreement for identical questions asked on two occasions about the frequency of physical activity decreased over time.This work was supported by public funds from Cancer
Research UK and the UK Medical Research Council
Composite endpoints for malaria case-management: not simplifying the picture?
Rapid diagnostic tests (RDTs) for infection with Plasmodium spp. offer two main potential advantages related to malaria treatment: 1) ensuring that individuals with malaria are promptly treated with an effective artemisinin-based combination therapy, and 2) ensuring that individuals without malaria do not receive an anti-malarial they do not need (and instead receive a more appropriate treatment). Some studies of the impact of RDTs on malaria case management have combined these two different successes into a binary outcome describing 'correct management'. However combining correct management of positives and negatives into a single summary measure can be misleading. The problems, which are analogous to those encountered in the evaluation of diagnostic tests, can largely be avoided if data for patients with and without malaria are presented and analysed separately. Where a combined metric is necessary, then one of the established approaches to summarise the performance of diagnostic tests could be considered, although these are not without their limitations. Two graphical approaches to help understand case management performance are illustrated
Self-replication and evolution of DNA crystals
Is it possible to create a simple physical system that is capable of replicating itself? Can such a system evolve interesting behaviors, thus allowing it to adapt to a wide range of environments? This paper presents a design for such a replicator constructed exclusively from synthetic DNA. The basis for the replicator is crystal growth: information is stored in the spatial arrangement of monomers and copied from layer to layer by templating. Replication is achieved by fragmentation of crystals, which produces new crystals that carry the same information. Crystal replication avoids intrinsic problems associated with template-directed mechanisms for replication of one-dimensional polymers. A key innovation of our work is that by using programmable DNA tiles as the crystal monomers, we can design crystal growth processes that apply interesting selective pressures to the evolving sequences. While evolution requires that copying occur with high accuracy, we show how to adapt error-correction techniques from algorithmic self-assembly to lower the replication error rate as much as is required
The Commission and Its Report: Public Education, Advocacy and Lobbying
Mr. Harris: The question concerning the justification of commissions of inquiry has been raised in the preceding discussions. If their sole justification is having the bulk of their recommendations implemented, the institution probably would have died out long ago. Nevertheless, it must be of considerable concern to commissioners that the record has not been good in terms of implementation and one of the questions that perhaps will determine how successful commissions are in this respect has to do with what happens when the report is delivered and thereafter. These questions will be largely the subject of the panel that we are about to present. You will not be treated to profound, scholarly papers on policy analysis or anything like that in this panel. There will be practical comments and suggestions
Linear law for the logarithms of the Riemann periods at simple critical zeta zeros
Each simple zero 1/2 + iγn of the Riemann zeta function on the critical line with γn > 0 is a center for the flow s˙ = ξ(s) of the Riemann xi function with an associated period Tn. It is shown that, as γn →∞, log Tn ≥ π/4 γn + O(log γn).
Numerical evaluation leads to the conjecture that this inequality can be replaced by an equality. Assuming the Riemann Hypothesis and a zeta zero separation conjecture γn+1 − γn≥ γn-θ for some exponent θ > 0, we obtain the upper bound log Tn ≤ γn2 + θ Assuming a weakened form of a conjecture of Gonek, giving a bound for the reciprocal of the derivative of zeta at each zero, we obtain the expected upper bound for the periods so, conditionally, log Tn = π/ 4 γn +O(log γn). Indeed, this linear relationship is equivalent to the given weakened conjecture, which implies the zero separation conjecture, provided the exponent is sufficiently large. The frequencies corresponding to the periods relate to natural eigenvalues for the Hilbert–Polya conjecture. They may provide a goal for those seeking a self-adjoint operator related to the Riemann hypothesis
Phase and Intensity Distributions of Individual Pulses of PSR B0950+08
The distribution of the intensities of individual pulses of PSR B0950+08 as a
function of the longitudes at which they appear is analyzed. The flux density
of the pulsar at 111 MHz varies strongly from day to day (by up to a factor of
13) due to the passage of the radiation through the interstellar plasma
(interstellar scintillation). The intensities of individual pulses can exceed
the amplitude of the mean pulse profile, obtained by accumulating 770 pulses,
by more than an order of magnitude. The intensity distribution along the mean
profile is very different for weak and strong pulses. The differential
distribution function for the intensities is a power law with index n = -1.1 +-
0.06 up to peak flux densities for individual pulses of the order of 160 Jy
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