Means and covariance functions for geostatistical compositional data: an axiomatic approach

This work focuses on the characterization of the central tendency of a sample of compositional data. It provides new results about theoretical properties of means and covariance functions for compositional data, with an axiomatic perspective. Original results that shed new light on the geostatistical modeling of compositional data are presented. As a first result, it is shown that the weighted arithmetic mean is the only central tendency characteristic satisfying a small set of axioms, namely continuity, reflexivity and marginal stability. Moreover, this set of axioms also implies that the weights must be identical for all parts of the composition. This result has deep consequences on the spatial multivariate covariance modeling of compositional data. In a geostatistical setting, it is shown as a second result that the proportional model of covariance functions (i.e., the product of a covariance matrix and a single correlation function) is the only model that provides identical kriging weights for all components of the compositional data. As a consequence of these two results, the proportional model of covariance function is the only covariance model compatible with reflexivity and marginal stability

Socio-economic variations in anticipated adverse reactions to testing HPV positive: Implications for the introduction of primary HPV-based cervical screening

Some cervical cancer screening programmes are replacing cytology with human papillomavirus (HPV) DNA testing as the primary screening test. Concerns have been previously raised around the potential psychosocial impact of testing positive for HPV. We analysed socio-economic variations in anticipated adverse reactions to testing positive for HPV in women of screening age in the general population. A questionnaire was mailed to a random sample of 5553 women aged 20-64 in 2010, selected through primary care in Ireland. This included questions on: socio-economics; HPV knowledge; and women's anticipated adverse psychosocial responses to testing HPV positive (shame, anxiety, stigma and worry). Multivariable linear regression was used to identify socio-economic factors significantly associated with each anticipated adverse reaction. The response rate was 62% (n = 3470). In multivariate analyses, having only attained primary level education were significantly associated with higher mean scores for all four adverse outcomes. Religion was significantly associated with all four adverse outcomes. Age was associated with anxiety and worry; younger women (<30 years) had the highest mean scores. Being married/cohabiting was significantly associated with significantly lower shame and worry scores. Not working was significantly associated with higher mean anxiety and worry scores. Our large population-based survey found significant socio-economic variations in anticipated adverse reactions to testing HPV positive. In order to minimise possible negative impacts on screening uptake and alleviate potential adverse psychological effects of HPV-based screening on women, screening programmes may need to develop specific messages around HPV infection and HPV screening that target certain subgroups of women

Terrestrial exposure of a fresh Martian meteorite causes rapid changes in hydrogen isotopes and water concentrations

Determining the hydrogen isotopic compositions and H2O contents of meteorites and their components is important for addressing key cosmochemical questions about the abundance and source(s) of water in planetary bodies. However, deconvolving the effects of terrestrial contamination from the indigenous hydrogen isotopic compositions of these extraterrestrial materials is not trivial, because chondrites and some achondrites show only small deviations from terrestrial values such that even minor contamination can mask the indigenous values. Here we assess the effects of terrestrial weathering and contamination on the hydrogen isotope ratios and H2O contents of meteoritic minerals through monitored terrestrial weathering of Tissint, a recent Martian fall. Our findings reveal the rapidity with which this weathering affects nominally anhydrous phases in extraterrestrial materials, which illustrates the necessity of sampling the interiors of even relatively fresh meteorite falls and underlines the importance of sample return missions

Trends in, and predictors of, anxiety and specific worries following colposcopy: a 12-month longitudinal study

Objective Little is known about which women are at greatest risk of adverse psychological after-effects following colposcopy. This study examined time trends in, and identified predictors of, anxiety and specific worries over 12 months. Methods Women attending two hospital-based colposcopy clinics for abnormal cervical cytology were invited to complete psychosocial questionnaires at 4, 8 and 12 months following colposcopy. General anxiety and screening-specific worries (about cervical cancer, having sex and future fertility) were measured. Generalised estimating equations were used to assess associations between socio-demographic, lifestyle and clinical variables and risk of psychological outcomes. Results Of 584 women initially recruited, 429, 343 and 303 completed questionnaires at 4, 8 and 12 months, respectively. Screening-specific worries declined significantly over time but were still relatively high at 12 months: 23%, 39% and 18% for worries about cervical cancer, fertility and having sex, respectively. Anxiety remained stable (20%) over time. Risks of cervical cancer worry and anxiety were both almost double in women without private health insurance (cervical cancer worry: OR = 1.80, 95% CI 1.25–2.61; anxiety: OR = 1.84, 95% CI 1.20–2.84). Younger women (<40 years) had higher risk of fertility worries. Non-Irish women had higher risk of anxiety (OR = 2.13, 95% CI 1.13–4.01). Conclusions Screening-specific worries declined over time but anxiety remained stable. Notable proportions of women still reported adverse outcomes 12 months following colposcopy, with predictors varying between outcomes. Women in socio-demographically vulnerable groups were at greatest risk of adverse psychological outcomes. This information could inform development of interventions to alleviate psychological distress post-colposcopy. Copyright © 2015 John Wiley & Sons, Ltd

"It's a can of worms": understanding primary care practitioners' behaviours in relation to HPV using the Theoretical Domains Framework

Background: The relationship between infection with high-risk human papillomavirus (HPV) and cervical cancer is transforming cervical cancer prevention. HPV tests and vaccinations have recently become available. In Ireland, as elsewhere, primary care practitioners play a key role in prevention. ATHENS (A Trial of HPV Education and Support) aims to develop a theorybased intervention to support primary care practitioners in their HPV-related practice. This study, the first step in the intervention development process, aimed to: identify HPV-related clinical behaviours that the intervention will target; clarify general practitioners’ (GPs’) and practice nurses’ roles and responsibilities; and determine factors that potentially influence clinical behaviour. A secondary objective was to informally assess the utility of the Theoretical Domains Framework (TDF) in understanding clinical behaviours in an area with an evolving evidence-base. Methods: In-depth semi-structured telephone interviews were conducted with GPs and practice nurses. The topic guide, which contained open questions and HPV-related clinical scenarios, was developed through literature review and clinical experience. Interview transcripts were content-analysed using the TDF as the coding framework. Results: 19 GPs and 14 practice nurses were interviewed. The major HPV-related clinical behaviours were: initiating a discussion about HPV infection with female patients; offering/recommending HPV vaccination to appropriate patients; and answering patients’ questions about HPV testing. While the responsibility for taking smears was considered a female role, both male and female practitioners dealt with HPV-related issues. All 12 theoretical domains arose in relation to HPV infection; the domains judged to be most important were: knowledge, emotion, social influences, beliefs about capabilities and beliefs about consequences. Eleven domains emerged in relation to HPV vaccination, with beliefs about consequences, social influences, knowledge and environmental context and resources judged to be the most important. Nine domains were relevant to HPV testing, with knowledge and beliefs about capabilities judged to be the most important. Conclusions: The findings confirm the need for an intervention to support primary care practitioners around HPV and suggest it should target a range of theoretical domains. The TDF proved valuable in analysing qualitative data collected using a topic guide not specifically designed to capture TDF domains and understanding clinical behaviours in an area with an evolving evidence-base

The Effect of Financial Incentives on Patient Decisions to Undergo Low‐value Head Computed Tomography Scans

BackgroundExcessive diagnostic testing and defensive medicine contribute to billions of dollars in avoidable costs in the United States annually. Our objective was to determine the influence of financial incentives, accompanied with information regarding test risk and benefit, on patient preference for diagnostic testing.MethodsWe conducted a cross‐sectional survey of patients at the University of Michigan emergency department (ED). Each participant was presented with a hypothetical scenario involving an ED visit following minor traumatic brain injury. Participants were given information regarding potential benefit (detecting brain hemorrhage) and risk (developing cancer) of head computed tomography scan, as well as an incentive of $0 or$100 to forego testing. We used 0.1 and 1% for test benefit and risk, and values for risk, benefit, and financial incentive varied across participants. Our primary outcome was patient preference to undergo testing. We also collected demographic and numeracy information. We then used logistic regression to estimate odds ratios (ORs), which were adjusted for multiple potential confounders. Our sample size was designed to find at least 300 events (preference for testing) to allow for inclusion of up to 30 covariates in fully adjusted models. We had 85% to 90% power to detect a 10% absolute difference in testing rate across groups, assuming a 95% significance level.ResultsWe surveyed 913 patients. Increasing test benefit from 0.1% to 1% significantly increased test acceptance (adjusted OR [AOR] = 1.6, 95% confidence interval [CI] = 1.2 to 2.1) and increasing test risk from 0.1% to 1% significantly decreased test acceptance (AOR = 0.70, 95% CI = 0.52 to 0.93). Finally, a $100 incentive to forego low‐value testing significantly reduced test acceptance (AOR = 0.6; 95% CI = 0.4 to 0.8).ConclusionsProviding financial incentives to forego testing significantly decreased patient preference for testing, even when accounting for test benefit and risk. This work is preliminary and hypothetical and requires confirmation in larger patient cohorts facing these actual decisions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151851/1/acem13823_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151851/2/acem13823-sup-0001-DataSupplementS1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151851/3/acem13823.pd

Radiative Transfer for Exoplanet Atmospheres

Remote sensing of the atmospheres of distant worlds motivates a firm understanding of radiative transfer. In this review, we provide a pedagogical cookbook that describes the principal ingredients needed to perform a radiative transfer calculation and predict the spectrum of an exoplanet atmosphere, including solving the radiative transfer equation, calculating opacities (and chemistry), iterating for radiative equilibrium (or not), and adapting the output of the calculations to the astronomical observations. A review of the state of the art is performed, focusing on selected milestone papers. Outstanding issues, including the need to understand aerosols or clouds and elucidating the assumptions and caveats behind inversion methods, are discussed. A checklist is provided to assist referees/reviewers in their scrutiny of works involving radiative transfer. A table summarizing the methodology employed by past studies is provided.Comment: 7 pages, no figures, 1 table. Filled in missing information in references, main text unchange

Injury rates and injury risk factors among federal bureau of investigation new agent trainees

<p>Abstract</p> <p>Background</p> <p>A one-year prospective examination of injury rates and injury risk factors was conducted in Federal Bureau of Investigation (FBI) new agent training.</p> <p>Methods</p> <p>Injury incidents were obtained from medical records and injury compensation forms. Potential injury risk factors were acquired from a lifestyle questionnaire and existing data at the FBI Academy.</p> <p>Results</p> <p>A total of 426 men and 105 women participated in the project. Thirty-five percent of men and 42% of women experienced one or more injuries during training. The injury incidence rate was 2.5 and 3.2 injuries/1,000 person-days for men and women, respectively (risk ratio (women/men) = 1.3, 95% confidence interval = 0.9-1.7). The activities most commonly associated with injuries (% of total) were defensive tactics training (58%), physical fitness training (20%), physical fitness testing (5%), and firearms training (3%). Among the men, higher injury risk was associated with older age, slower 300-meter sprint time, slower 1.5-mile run time, lower total points on the physical fitness test (PFT), lower self-rated physical activity, lower frequency of aerobic exercise, a prior upper or lower limb injury, and prior foot or knee pain that limited activity. Among the women higher injury risk was associated with slower 300-meter sprint time, slower 1.5-mile run time, lower total points on the PFT, and prior back pain that limited activity.</p> <p>Conclusion</p> <p>The results of this investigation supported those of a previous retrospective investigation emphasizing that lower fitness and self-reported pain limiting activity were associated with higher injury risk among FBI new agents.</p

Estimation of proteinuria as a predictor of complications of pre-eclampsia: a systematic review

Background Proteinuria is one of the essential criteria for the clinical diagnosis of pre-eclampsia. Increasing levels of proteinuria is considered to be associated with adverse maternal and fetal outcomes. We aim to determine the accuracy with which the amount of proteinuria predicts maternal and fetal complications in women with pre-eclampsia by systematic quantitative review of test accuracy studies. Methods We conducted electronic searches in MEDLINE (1951 to 2007), EMBASE (1980 to 2007), the Cochrane Library (2007) and the MEDION database to identify relevant articles and hand-search of selected specialist journals and reference lists of articles. There were no language restrictions for any of these searches. Two reviewers independently selected those articles in which the accuracy of proteinuria estimate was evaluated to predict maternal and fetal complications of pre-eclampsia. Data were extracted on study characteristics, quality and accuracy to construct 2 × 2 tables with maternal and fetal complications as reference standards. Results Sixteen primary articles with a total of 6749 women met the selection criteria with levels of proteinuria estimated by urine dipstick, 24-hour urine proteinuria or urine protein:creatinine ratio as a predictor of complications of pre-eclampsia. All 10 studies predicting maternal outcomes showed that proteinuria is a poor predictor of maternal complications in women with pre-eclampsia. Seventeen studies used laboratory analysis and eight studies bedside analysis to assess the accuracy of proteinuria in predicting fetal and neonatal complications. Summary likelihood ratios of positive and negative tests for the threshold level of 5 g/24 h were 2.0 (95% CI 1.5, 2.7) and 0.53 (95% CI 0.27, 1) for stillbirths, 1.5 (95% CI 0.94, 2.4) and 0.73 (95% CI 0.39, 1.4) for neonatal deaths and 1.5 (95% 1, 2) and 0.78 (95% 0.64, 0.95) for Neonatal Intensive Care Unit admission. Conclusion Measure of proteinuria is a poor predictor of either maternal or fetal complications in women with pre-eclampsia