Yet another breakdown point notion: EFSBP - illustrated at scale-shape models

The breakdown point in its different variants is one of the central notions to quantify the global robustness of a procedure. We propose a simple supplementary variant which is useful in situations where we have no obvious or only partial equivariance: Extending the Donoho and Huber(1983) Finite Sample Breakdown Point, we propose the Expected Finite Sample Breakdown Point to produce less configuration-dependent values while still preserving the finite sample aspect of the former definition. We apply this notion for joint estimation of scale and shape (with only scale-equivariance available), exemplified for generalized Pareto, generalized extreme value, Weibull, and Gamma distributions. In these settings, we are interested in highly-robust, easy-to-compute initial estimators; to this end we study Pickands-type and Location-Dispersion-type estimators and compute their respective breakdown points.Comment: 21 pages, 4 figure

A fast Metropolis-Hastings method for generating random correlation matrices

We propose a novel Metropolis-Hastings algorithm to sample uniformly from the space of correlation matrices. Existing methods in the literature are based on elaborated representations of a correlation matrix, or on complex parametrizations of it. By contrast, our method is intuitive and simple, based the classical Cholesky factorization of a positive definite matrix and Markov chain Monte Carlo theory. We perform a detailed convergence analysis of the resulting Markov chain, and show how it benefits from fast convergence, both theoretically and empirically. Furthermore, in numerical experiments our algorithm is shown to be significantly faster than the current alternative approaches, thanks to its simple yet principled approach.Comment: 8 pages, 3 figures, 2018 conferenc

Risk scores for predicting HIV incidence among adult heterosexual populations in sub-Saharan Africa: a systematic review and meta-analysis.

This is the final version. Available on open access from Wiley via the DOI in this record. Data availability statement: All data extracted for this systematic review are contained in the manuscript and supporting information.INTRODUCTION: Several HIV risk scores have been developed to identify individuals for prioritized HIV prevention in sub-Saharan Africa. We systematically reviewed HIV risk scores to: (1) identify factors that consistently predicted incident HIV infection, (2) review inclusion of community-level HIV risk in predictive models and (3) examine predictive performance. METHODS: We searched nine databases from inception until 15 February 2021 for studies developing and/or validating HIV risk scores among the heterosexual adult population in sub-Saharan Africa. Studies not prospectively observing seroconversion or recruiting only key populations were excluded. Record screening, data extraction and critical appraisal were conducted in duplicate. We used random-effects meta-analysis to summarize hazard ratios and the area under the receiver-operating characteristic curve (AUC-ROC). RESULTS: From 1563 initial search records, we identified 14 risk scores in 13 studies. Seven studies were among sexually active women using contraceptives enrolled in randomized-controlled trials, three among adolescent girls and young women (AGYW) and three among cohorts enrolling both men and women. Consistently identified HIV prognostic factors among women were younger age (pooled adjusted hazard ratio: 1.62 [95% confidence interval: 1.17, 2.23], compared to above 25), single/not cohabiting with primary partners (2.33 [1.73, 3.13]) and having sexually transmitted infections (STIs) at baseline (HSV-2: 1.67 [1.34, 2.09]; curable STIs: 1.45 [1.17; 1.79]). Among AGYW, only STIs were consistently associated with higher incidence, but studies were limited (n = 3). Community-level HIV prevalence or unsuppressed viral load strongly predicted incidence but was only considered in 3 of 11 multi-site studies. The AUC-ROC ranged from 0.56 to 0.79 on the model development sets. Only the VOICE score was externally validated by multiple studies, with pooled AUC-ROC 0.626 [0.588, 0.663] (I2 : 64.02%). CONCLUSIONS: Younger age, non-cohabiting and recent STIs were consistently identified as predicting future HIV infection. Both community HIV burden and individual factors should be considered to quantify HIV risk. However, HIV risk scores had only low-to-moderate discriminatory ability and uncertain generalizability, limiting their programmatic utility. Further evidence on the relative value of specific risk factors, studies populations not restricted to "at-risk" individuals and data outside South Africa will improve the evidence base for risk differentiation in HIV prevention programmes. PROSPERO NUMBER: CRD42021236367.Bill and Melinda Gates FoundationMedical Research Council (MRC)UNAIDSUK Foreign, Commonwealth & Development Office (FCDO

Subthreshold depression as a risk indicator for major depressive disorder: a systematic review of prospective studies.

Objective: In order to examine whether the incidence of major depressive disorder (MDD) is increased in subjects with subthreshold depression, or sD (clinically relevant depressive symptoms, without meeting criteria for a full-blown MDD), we conducted a review of prospective studies examining the incidence of MDD in subjects with sD. Method: A systematic literature search was conducted. For all studies, the relative risk of developing MDD was calculated, based on person-years. Results: Twenty studies (23 comparisons) were found, based on community samples, general medical patients and high-risk subjects. Most comparisons showed that subjects with sD had a consistently larger chance of developing MDD. The studies differed considerably in the definition of sD, the recency (occurrence of the last sD) and the in-/ exclusion of lifetime MDD. Conclusion: The incidence of MDD in subjects with sD is larger than in subjects without sD. Otherwise, the concept of sD is too broad to be used. In future studies, some consensus should be reached regarding the definition of sD

Neuronal circuitry for pain processing in the dorsal horn

Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region

Cimetidine in colorectal cancer – are the effects immunological or adhesion-mediated?

British Journal of Cancer (2002) 86, 159–160. DOI: 10.1038/sj/bjc/6600097 www.bjcancer.co

The Effects of Stress at Work and at Home on Inflammation and Endothelial Dysfunction

This study examined whether stress at work and at home may be related to dysregulation of inflammation and endothelial function, two important contributors to the development of cardiovascular disease. In order to explore potential biological mechanisms linking stress with cardiovascular health, we investigated cross-sectional associations between stress at work and at home with an inflammation score (n's range from 406–433) and with two endothelial biomarkers (intercellular and vascular adhesion molecules, sICAM-1 and sVCAM-1; n's range from 205–235) in a cohort of healthy US male health professionals. No associations were found between stress at work or at home and inflammation. Men with high or medium levels of stress at work had significantly higher levels of sVCAM-1 (13% increase) and marginally higher levels of sICAM-1 (9% increase), relative to those reporting low stress at work, independent of health behaviors. Men with high levels of stress at home had marginally higher levels of both sVCAM-1 and sICAM-1 than those with low stress at home. While lack of findings related to inflammation are somewhat surprising, if replicated in future studies, these findings may suggest that endothelial dysfunction is an important biological mechanism linking stress at work with cardiovascular health outcomes in men