Measuring Sulfur Isotope Ratios from Solid Samples with the Sample Analysis at Mars Instrument and the Effects of Dead Time Corrections

The Sample Analysis at Mars (SAM) instrument suite comprises the largest science payload on the Mars Science Laboratory (MSL) "Curiosity" rover. SAM will perform chemical and isotopic analysis of volatile compounds from atmospheric and solid samples to address questions pertaining to habitability and geochemical processes on Mars. Sulfur is a key element of interest in this regard, as sulfur compounds have been detected on the Martian surface by both in situ and remote sensing techniques. Their chemical and isotopic composition can belp constrain environmental conditions and mechanisms at the time of formation. A previous study examined the capability of the SAM quadrupole mass spectrometer (QMS) to determine sulfur isotope ratios of SO2 gas from a statistical perspective. Here we discuss the development of a method for determining sulfur isotope ratios with the QMS by sampling SO2 generated from heating of solid sulfate samples in SAM's pyrolysis oven. This analysis, which was performed with the SAM breadboard system, also required development of a novel treatment of the QMS dead time to accommodate the characteristics of an aging detector

An analysis of recent stroke cases in South Africa: Trend, seasonality and predictors

Background. South Africa (SA) is experiencing an epidemiological transition as a result of sociodemographic and lifestyle changes. This process is leading to an increase in non-communicable diseases, which in turn may result in an upswing of stroke cases. Stroke is among the top 10 leading causes of disability in SA, and accounts for ~25 000 deaths annually and 95 000 years lived with disability (YLD). This huge burden of stroke hampers socioeconomic development as a result of YLD. Objectives. To investigate the seasonality and trend of stroke cases in SA, and determine the risk factors associated with stroke. Methods. Using recent hospital-based data (January 2014 - December 2017 inclusive) from SA private and public hospitals (33% private and 67% public), a sample of 14 645 suspected stroke cases was drawn. Associations between suspected stroke cases and potential predictors were assessed using χ2 tests and bivariate analysis. Time series analysis tools for trend and seasonality components included both time domain and frequency domain techniques. A Poisson generalised linear model was used, as there was no over-dispersion inherent in the data. Multiple logistic regression analysis was used to assess the effect of several predictors on stroke cases. Results. Of the 14 645 suspected cases of stroke, 51.5% were confirmed. Seasonality analysis gave an approximate seasonal change of 120 cases, the highest seasonal peak occurring in mid-winter and the lowest dip in mid-summer. Both upward trend and seasonality parameters were found to be statistically significant. Predictors significantly associated with an increased likelihood of stroke were heart problems (odds ratio (OR) 8.86; 95% confidence interval (CI) 8.23 - 9.55; p<0.0001), diabetes (OR 14.53; 95% CI 13.36 - 15.79; p<0.0001), female sex (OR 18.23; 95% CI 16.75 - 19.85; p<0.0001), age 59 - 77 years (OR 1.37; 95% CI 1.24 - 1.50; p<0.0001) and 78 - 98 years (OR 1.25; 95% CI 1.16 - 1.35; p<0.0001) and white ethnic group (OR 2.00; 95% CI 1.86 - 2.15; p<0.0001), compared with the respective reference groups. The prevalence ratios of stroke cases as measured by Poisson regression were in agreement with logistic regression results. Conclusions. The increasing trend of stroke in SA should be arrested urgently, taking into account both the associated risk factors and seasonality.Statistic

Exact diagonalization of the S=1/2 Heisenberg antiferromagnet on finite bcc lattices to estimate properties on the infinite lattice

Here we generate finite bipartite body-centred cubic lattices up to 32 vertices. We have studied the spin one half Heisenberg antiferromagnet by diagonalizing its Hamiltonian on each of the finite lattices and hence computing its ground state properties. By extrapolation of these data we obtain estimates of the T = 0 properties on the infinite bcc lattice. Our estimate of the T = 0 energy agrees to five parts in ten thousand with third order spin wave and series expansion method estimates, while our estimate of the staggered magnetization agrees with the spin wave estimate to within a quarter of one percent.Comment: 16 pages, LaTeX, 1 ps figure, to appear in J.Phys.

Calibration of the Neutral Mass Spectrometer for the Lunar Atmosphere and Dust Environment Explorer

Science objectives of the LADEE Mission are to (1) determine the composition, and time variability of the tenuous lunar atmosphere and (2) to characterize the dust environment and its variability. These studies will extend the in-situ characterization of the environment that were carried out decades ago with the Apollo missions and a variety of ground based studies. The focused LADEE measurements will enable a more complete understanding of dust and gas sources and sinks. Sources of gas include UV photo-stimulated desorption, sputtering by plasma and micrometeorites, as well as thermal release of species such as argon from the cold service or venting from the lunar interior. Sinks include recondensation on the surface and escape through a variety of mechanisms. The LADEE science payload consists of an Ultraviolet Spectrometer, a Neutral Mass Spectrometer, and a Dust Detector. The LADEE orbit will include multiple passes at or below 50 km altitude and will target repeated sampling at the sunrise terminator where exospheric density will be highest for some thermally released species. The science mission will be implemented in approximately three months to allow measurements to be made over a period of one or more lunations In addition to the science mission NASA will use this mission to demonstrate optical communication technology away from low Earth orbit

Calibration of the Quadrupole Mass Spectrometer of the Sample Analysis at Mars Instrument Suite

The SAM suite of instruments on the "Curiosity" Rover of the Mars Science Laboratory (MSL) is designed to provide chemical and isotopic analysis of organic and inorganic volatiles for both atmospheric and solid samples. The mission of the MSL investigations is to advance beyond the successful search for aqueous transformation in surface environments at Mars toward a quantitative assessment of habitability and preservation through a series of chemical and geological measurements. The SAM suite was delivered in December 2010 (Figure 1) to the Jet Propulsion Laboratory for integration into the Curiosity Rover. We previously outlined the range of SAM solid and gas calibrations implemented or planned and here we discuss a specific set of calibration experiments to establish the response of the SAM Quadrupole Mass Spectrometer (QMS) to the four most abundant gases in the Martian atmosphere CO2, N2, Ar, and O2, A full SAM instrument description and calibration report is presently in preparation

Can virtual International exchanges improve primary health care?

Aims/Objectives/background: Globalisation has a significant impact on our health through an increasingly interconnected world and, even before the COVID pandemic, there were calls in the medical literature for all doctors to have up-to-date training in important global health issues. Traditionally doctors developed skills in international medicine through medical electives overseas but these often precluded qualified doctors with work and family commitment, and have been limited by COVID for the foreseeable future. An alternative, innovative approach may be through ‘virtual international exchanges’. Content: A systematic literature review on ‘virtual international exchange’ (VIE) and ‘collaborative online international learning’ for health care professionals was undertaken to determine the potential benefits of developing virtual international exchanges for local GPs and GP trainees. We summarise the literature and discuss key themes that emerged, such as the ability of virtual exchanges to foster cross cultural understanding; improve communications skills; enhance learning of clinical topics; and prepare clinicians to work in multicultural environments. Relevance/Impact: Virtual international exchanges offer an innovative means to develop cross cultural understanding, foster sustainable links between primary healthcare clinicians and promote good practice internationally. Outcomes/Discussion: International exchanges for NHS doctors have often been available for the privileged few with many qualified GPs not being able to travel overseas due to work and family commitments. COVID has made them unlikely for anyone for the forthcoming future. We aim to pilot VIE for GPs locally and further research is needed to establish how they can best promote excellence in primary healthcare internationally

Improving Empathy in Healthcare Consultations-a Secondary Analysis of Interventions.

A recent systematic review of randomised trials suggested that empathic communication improves patient health outcomes. However, the methods for training healthcare practitioners (medical professionals; HCPs) in empathy and the empathic behaviours demonstrated within the trials were heterogeneous, making the evidence difficult to implement in routine clinical practice. In this secondary analysis of seven trials in the review, we aimed to identify (1) the methods used to train HCPs, (2) the empathy behaviours they were trained to perform and (3) behaviour change techniques (BCTs) used to encourage the adoption of those behaviours. This detailed understanding of interventions is necessary to inform implementation in clinical practice. We conducted a content analysis of intervention descriptions, using an inductive approach to identify training methods and empathy behaviours and a deductive approach to describe the BCTs used. The most commonly used methods to train HCPs to enhance empathy were face-to-face training (n = 5), role-playing (n = 3) and videos (self or model; n = 3). Duration of training was varied, with both long and short training having high effect sizes. The most frequently targeted empathy behaviours were providing explanations of treatment (n = 5), providing non-specific empathic responses (e.g. expressing understanding) and displaying a friendly manner and using non-verbal behaviours (e.g. nodding, leaning forward, n = 4). The BCT most used to encourage HCPs to adopt empathy behaviours was "Instruction on how to perform behaviour" (e.g. a video demonstration, n = 5), followed by "Credible source" (e.g. delivered by a psychologist, n = 4) and "Behavioural practice" (n = 3 e.g. role-playing). We compared the effect sizes of studies but could not extrapolate meaningful conclusions due to high levels of variation in training methods, empathy skills and BCTs. Moreover, the methods used to train HCPs were often poorly described which limits study replication and clinical implementation. This analysis of empathy training can inform future research, intervention reporting standards and clinical practice