Edgeworth Expansions for the Distribution Function of the Hill Estimator

We establish Edgeworth expansions for the distribution function of the centered and normalized Hill estimator for the positive extreme value index.estimation;variation;statistical distribution

A systematic review of tuberculosis detection and prevention studies in prisons

Many studies have demonstrated that prisons are hotspots of tuberculosis disease and transmission. Despite this, it remains unclear which interventions are most effective at controlling tuberculosis in prisons. The objective was to determine the study designs used to investigate tuberculosis control in prisons, and the efficacy of interventions undertaken. This systematic review included published studies which had the aim of reducing TB incidence or prevalence, or increasing the number of people screened for active pulmonary tuberculosis in incarcerated populations. 2,429 records were identified, 178 full-text articles were screened, and 17 studies included. The majority of reports were before/after or prospective non-comparative studies. The median study duration was 23 months (range 5-144). The most common intervention was the introduction of active case finding (10/17 studies) but the timing and methods varied. Comparable pre- and post intervention outcome values were infrequently reported; therefore, it was not possible to quantify the efficacy of interventions. Data from studies of tuberculosis control in prisons is limited by a lack of: controlled interventions, reporting of pre-intervention methods, and comparable pre- and post-intervention outcomes. Prospective comparative trials of adequate duration to determine trends in incidence are necessary to understand which interventions are effective in prisons

Mind the message: Referral letter quality at a South African medical outpatient department

Background. Some patients need referral within the health system to achieve optimal care, and referral letters are an important part of this process. Healthcare practitioners often complain that referral letters lack information, are inaccurate, or direct patients to the wrong place. Poor communication affects patient experience and outcomes, has budgetary and service planning implications, and impacts on staff relationships and morale.Objectives. To investigate the quality and appropriateness of referral letters received by the medical outpatient department of a regional hospital in Eastern Cape Province, South Africa.Methods. Letters were collected by departmental staff as patients arrived at the clinic. Each letter was independently analysed by two healthcare workers for content and appropriateness, using defined criteria.Results. Of 100 letters collected between March and May 2017, 85 were suitable for analysis. Patient and clinician identifiers were present in >85%, but key clinical information was missing in 87%, and 48% did not state a reason for referral. It was possible to make triage decisions based on the letter in only 35% of cases. Nineteen percent of referrals were classified as inappropriate.Conclusions. Most letters lacked important clinical information, probably because of a combination of factors: gaps in clinical knowledge of referring clinicians who service a population with a high burden of disease and complex pathology; under-resourced peripheral healthcare clinics; inadequate staff-to-patient ratios; and time constraints. A suggested focus for improvement is education at undergraduate and postgraduate level, which should emphasise preparation for community service, specifically highlighting techniques for preparing good-quality referrals

Sex classification using the human sacrum: Geometric morphometrics versus conventional approaches

The human pelvis shows marked sexual dimorphism that stems from the conflicting selective pressures of bipedal locomotion and parturition. The sacrum is thought to reflect this dimorphism as it makes up a significant portion of the pelvic girdle. However, reported sexual classification accuracies vary considerably depending on the method and reference sample (54%-98%). We aim to explore this inconsistency by quantifying sexual dimorphism and sex classification accuracies in a geographically heterogeneous sample by comparing 3D geometric morphometrics with the more commonly employed linear metric and qualitative assessments. Our sample included 164 modern humans from Africa, Europe, Asia, and America. The geometric morphometric analysis was based on 44 landmarks and 56 semilandmarks. Linear dimensions included sacral width, corpus depth and width, and the corresponding indices. The qualitative inspection relied on traditional macroscopic features such as proportions between the corpus of the first sacral vertebrae and the alae, and sagittal and coronal curvature of the sacrum. Classification accuracy was determined using linear discriminant function analysis for the entire sample and for the largest subsamples (i.e., Europeans and Africans). Male and female sacral shapes extensively overlapped in the geometric morphometric investigation, leading to a classification accuracy of 72%. Anteroposterior corpus depth was the most powerful discriminating linear parameter (83%), followed by the corpus-area index (78%). Qualitative inspection yielded lower accuracies (64–76%). Classification accuracy was higher for the Central European subsample and diminished with increasing geographical heterogeneity of the subgroups. Although the sacrum forms an integral part of the birth canal, our results suggest that its sex-related variation is surprisingly low. Morphological variation thus seems to be driven also by other factors, including body size, and sacrum shape is therefore likely under stronger biomechanical rather than obstetric selection