Investigation of heaterless hollow cathode breakdown

The development of long life high powered (>50A) hollow cathodes is of importance to meet the demand of increasingly powerful Gridded Ion engines and Hall Effect thrusters. High power cathodes typically operate at greater temperature ranges, which poses a significant challenge to maintain heater reliability. The heater component commonly used to raise the insert to emissive temperatures, has inherent reliability issues from thermal fatigue caused by thermal cycling with large temperature variations. A self-heating hollow cathode allows for potentially higher reliability through design simplicity of removing the heater component, and in addition there can be savings in mass, volume, ignition time and power. This study characterizes the initiation of the start-up process for a heaterless hollow cathode. As such the study analyses conditions of the initiation as a function of detailed geometrical and physical parameters. The Paschen curve can be seen to give a qualitative explanation for the breakdown voltage variance. The quantitative variations between the empirical results and Paschen curve are discussed in relation to non-uniform pressure simulations

A nonparametric urn-based approach to interacting failing systems with an application to credit risk modeling

In this paper we propose a new nonparametric approach to interacting failing systems (FS), that is systems whose probability of failure is not negligible in a fixed time horizon, a typical example being firms and financial bonds. The main purpose when studying a FS is to calculate the probability of default and the distribution of the number of failures that may occur during the observation period. A model used to study a failing system is defined default model. In particular, we present a general recursive model constructed by the means of inter- acting urns. After introducing the theoretical model and its properties we show a first application to credit risk modeling, showing how to assess the idiosyncratic probability of default of an obligor and the joint probability of failure of a set of obligors in a portfolio of risks, that are divided into reliability classes

Think of your art-eries: Arts participation, behavioural cardiovascular risk factors and mental well-being in deprived communities in London

Objectives: To investigate the association of participation in arts and cultural activities with health behaviours and mental well-being in low-income populations in London. Study design: Cross-sectional, community-based observational study. Methods: Data were taken from the cross-sectional baseline survey of the Well London cluster randomized trial, conducted during 2008 in 40 of the most deprived census lower super output areas in London (selected using the English Indices of Multiple Deprivation). Multiple imputation was used to account for missing data in the Well London survey. Descriptive statistics and regression analyses were used to examine the association between participation in arts and cultural activities and physical activity (meeting target of five sessions of at least 30 min of moderate-intensity physical activity per week), healthy eating (meeting target of at least five portions of fruit or vegetables per day) and mental well-being (Hope Scale score; feeling anxious or depressed). Results: This study found that levels of arts and cultural engagement in low-income groups in London are >75%, but this is well below the national average for England. Individuals who were more socially disadvantaged (unemployed, living in rented social housing, low educational attainment, low disposable income) were less likely to participate in arts or cultural activities. Arts participation was strongly associated with healthy eating, physical activity and positive mental well-being, with no evidence of confounding by socioeconomic or sociodemographic factors. Neither positive mental well-being nor social capital appeared to mediate the relationship between arts participation and health behaviours. Conclusion: This study suggests that arts and cultural activities are independently associated with health behaviours and mental well-being. Further qualitative and prospective intervention studies are needed to elucidate the nature of the relationship between health behaviours, mental well-being and arts participation. If arts activities are to be recommended for health improvement, social inequalities in access to arts and cultural activities must be addressed in order to prevent further reinforcement of health inequalities

The role of social capital in participatory arts for wellbeing: findings from a qualitative systematic review

Background Social capital is often cited as shaping impacts of participatory arts, although the concept has not been systematically mapped in arts, health and wellbeing contexts. In wider health inequalities research, complex, differential, and sometimes negative impacts of social capital have been recognised. Methods This paper maps of social capital concepts in qualitative research as part of the UK What Works for Wellbeing evidence review programme on culture, sport and wellbeing. Results Studies often cite positive impacts of bonding and, to a lesser extent, bridging social capital. However, reported challenges suggest the need for a critical approach. Forms of linking social capital, such as reframing and political engagement to address social divisions, are less often cited but may be important in participatory arts and wellbeing. Conclusions Future research should further specify dimensions of social capital as well as their nuanced effects in arts, and wellbeing contexts.Economic & Social Research Council grant number ES/N003721/1, as part of the evidence review programme for the UK What Works Centre for Wellbeing

Broadband Laser Ranging for Explosive Experiments

Author Institution: National Security Technologies, LLC Special Technologies Laboratory; Lawrence Livermore National Laboratory; Los Alamos National LaboratorySlides presented at the 2016 Photonic Doppler Velocimetry (PDV) unclassified program, Bankhead Theater, Livermore, California, June 7 - 9, 2016. Plenary Talk 3, June 9, 2016

The role of social capital in participatory arts for wellbeing: findings from a qualitative systematic review

BACKGROUND:Social capital is often cited as shaping impacts of participatory arts, although the concept has not been systematically mapped in arts, health and wellbeing contexts. In wider health inequalities research, complex, differential, and sometimes negative impacts of social capital have been recognised. METHODS:This paper maps of social capital concepts in qualitative research as part of the UK What Works for Wellbeing evidence review programme on culture, sport and wellbeing. RESULTS:Studies often cite positive impacts of bonding and, to a lesser extent, bridging social capital. However, reported challenges suggest the need for a critical approach. Forms of linking social capital, such as reframing and political engagement to address social divisions, are less often cited but may be important in participatory arts and wellbeing. CONCLUSIONS:Future research should further specify dimensions of social capital as well as their nuanced effects in arts, and wellbeing contexts

A key role for STIM1 in store operated calcium channel activation in airway smooth muscle

BACKGROUND: Control of cytosolic calcium plays a key role in airway myocyte function. Changes in intracellular Ca(2+ )stores can modulate contractile responses, modulate proliferation and regulate synthetic activity. Influx of Ca(2+ )in non excitable smooth muscle is believed to be predominantly through store operated channels (SOC) or receptor operated channels (ROC). Whereas agonists can activate both SOC and ROC in a range of smooth muscle types, the specific trigger for SOC activation is depletion of the sarcoplasmic reticulum Ca(2+ )stores. The mechanism underlying SOC activation following depletion of intracellular Ca(2+ )stores in smooth muscle has not been identified. METHODS: To investigate the roles of the STIM homologues in SOC activation in airway myocytes, specific siRNA sequences were utilised to target and selectively suppress both STIM1 and STIM2. Quantitative real time PCR was employed to assess the efficiency and the specificity of the siRNA mediated knockdown of mRNA. Activation of SOC was investigated by both whole cell patch clamp electrophysiology and a fluorescence based calcium assay. RESULTS: Transfection of 20 nM siRNA specific for STIM1 or 2 resulted in robust decreases (>70%) of the relevant mRNA. siRNA targeted at STIM1 resulted in a reduction of SOC associated Ca(2+ )influx in response to store depletion by cyclopiazonic acid (60%) or histamine but not bradykinin. siRNA to STIM2 had no effect on these responses. In addition STIM1 suppression resulted in a more or less complete abrogation of SOC associated inward currents assessed by whole cell patch clamp. CONCLUSION: Here we show that STIM1 acts as a key signal for SOC activation following intracellular Ca(2+ )store depletion or following agonist stimulation with histamine in human airway myocytes. These are the first data demonstrating a role for STIM1 in a physiologically relevant, non-transformed endogenous expression cell model

Genetic information: important but not "exceptional"

Much legislation dealing with the uses of genetic information could be criticised for exceptionalising genetic information over other types of information personal to the individual. This paper contends that genetic exceptionalism clouds the issues, and precludes any real debate about the appropriate uses of genetic information. An alternative to “genetically exceptionalist” legislation is to “legislate for fairness”. This paper explores the “legislating for fairness” approach, and concludes that it demonstrates a fundamental misunderstanding of both how legislation is drafted, and how it is interpreted. The uncomfortable conclusion is this: policy-makers and legislators must tackle head-on the difficult policy questions concerning what should and should not be done with genetic information. Only by confronting this crucial issue will they achieve a workable legislative solution to the problems caused by genetic information

Metabolic Signatures of Lung Cancer in Biofluids: NMR-Based Metabonomics of Blood Plasma

In this work, the variations in the metabolic profile of blood plasma from lung cancer patients and healthy controls were investigated through NMR-based metabonomics, to assess the potential of this approach for lung cancer screening and diagnosis. PLS-DA modeling of CPMG spectra from plasma, subjected to Monte Carlo Cross Validation, allowed cancer patients to be discriminated from controls with sensitivity and specificity levels of about 90%. Relatively lower HDL and higher VLDL + LDL in the patients' plasma, together with increased lactate and pyruvate and decreased levels of glucose, citrate, formate, acetate, several amino acids (alanine, glutamine, histidine, tyrosine, valine), and methanol, could be detected. These changes were found to be present at initial disease stages and could be related to known cancer biochemical hallmarks, such as enhanced glycolysis, glutaminolysis, and gluconeogenesis, together with suppressed Krebs cycle and reduced lipid catabolism, thus supporting the hypothesis of a systemic metabolic signature for lung cancer. Despite the possible confounding influence of age, smoking habits, and other uncontrolled factors, these results indicate that NMR-based metabonomics of blood plasma can be useful as a screening tool to identify suspicious cases for subsequent, more specific radiological tests, thus contributing to improved disease management.ERDF - Competitive Factors Thematic Operational ProgrammeFCT/PTDC/ QUI/68017/2006FCOMP-01-0124-FEDER-007439SFRH/BD/ 63430/2009National UNESCO Committee - L'Oréal Medals of Honor for Women in Science 200Portuguese National NMR Network - RNRM