Relationship of a big five personality questionnaire to the symptoms of affective disorders

Online assessments allow cost-effective, large-scale screening for psychiatric vulnerability (e.g., university undergraduates or military recruits). However, conventional psychiatric questionnaires may worsen mental health outcomes due to overmedicalizing normal emotional reactions. Personality questionnaires designed for occupational applications could circumvent this problem as they utilise non-clinical wording and it is well-established that personality traits influence susceptibility to psychiatric illness. Here we present a brief, free-to-use occupational personality questionnaire, and test its sensitivity to symptoms of Bipolar Disorder (BD) and Major Depressive Disorder (MDD) in an online sample. Our study used a cross-sectional, self-report design to assess the relationship between self-reported symptoms of affective disorders and scores on the personality dimensions of openness, conscientiousness, extraversion, agreeableness and neuroticism. We used SEM to compare affective symptoms in 8,470 individuals (mean age 25.6 ± 7.0 years; 4,717 male) with scores on an online adaption of the TSDI, a public-domain ‘Big Five’ personality questionnaire. ROC curve analyses assessed cut off scores for the best predictors of overall vulnerability to affective disorders (represented by a composite screening score). Neuroticism was the most robust predictor of QIDS-16 depression symptoms and MDQ Hypomania symptoms (β = 0.68 and 0.39 respectively, p < .0001). Extraversion was the most robust predictor of HCL-16 Hypomania symptoms (β = 0.34, p < .0001). ROC curve analyses suggest if the TSDI was used for screening in this sample, neuroticism cut offs of approximately 58 for men and 70 for women would provide the most useful classification of overall vulnerability to affective disorders

Differential effects of exercise on tibial shaft marrow density in young female athletes

Context:Increased mechanical loading can promote the preferential differentiation of bone marrow mesenchymal stem cells to osteoblastogenesis, but it is not known whether long-term bone strength-enhancing exercise in humans can reduce marrow adiposity.Objective:Our objective was to examine whether bone marrow density (MaD), as an estimate of marrow adiposity 1) differs between young female athletes with contrasting loading histories and bone strengths and 2) is an independent predictor of bone strength at the weight-bearing tibia.Design:Mid-tibial MaD, cortical area (CoA), total area, medullary area, strength strain index (SSI), and cortical volumetric bone mineral density (vBMD) (total, endocortical, midcortical, and pericortical) was assessed using peripheral quantitative computed tomography in 179 female athletes involved in both impact and nonimpact loading sports and 41 controls aged 17&ndash;40 years.Results:As we have previously reported CoA, total area, and SSI were 16% to 24% greater in the impact group compared with the controls (all P &lt; .001) and 12% to 18% greater than in the nonimpact group (all P &lt; .001). The impact group also had 0.5% higher MaD than the nonimpact and control groups (both P &lt; .05). Regression analysis further showed that midtibial MaD was significantly associated with SSI, CoA, endocortical vBMD, and pericortical vBMD (P &lt; .05) in all women combined, after adjusting for age, bone length, loading groups, medullary area, muscle cross-sectional area, and percent fat.Conclusion:In young female athletes, tibial bone MaD was associated with loading history and was an independent predictor of tibial bone strength. These findings suggest that an exercise-induced increase in bone strength may be mediated via reduced bone marrow adiposity and consequently increased osteoblastogenesis.<br /

Maximum-likelihood estimation of lithospheric flexural rigidity, initial-loading fraction, and load correlation, under isotropy

Topography and gravity are geophysical fields whose joint statistical structure derives from interface-loading processes modulated by the underlying mechanics of isostatic and flexural compensation in the shallow lithosphere. Under this dual statistical-mechanistic viewpoint an estimation problem can be formulated where the knowns are topography and gravity and the principal unknown the elastic flexural rigidity of the lithosphere. In the guise of an equivalent "effective elastic thickness", this important, geographically varying, structural parameter has been the subject of many interpretative studies, but precisely how well it is known or how best it can be found from the data, abundant nonetheless, has remained contentious and unresolved throughout the last few decades of dedicated study. The popular methods whereby admittance or coherence, both spectral measures of the relation between gravity and topography, are inverted for the flexural rigidity, have revealed themselves to have insufficient power to independently constrain both it and the additional unknown initial-loading fraction and load-correlation fac- tors, respectively. Solving this extremely ill-posed inversion problem leads to non-uniqueness and is further complicated by practical considerations such as the choice of regularizing data tapers to render the analysis sufficiently selective both in the spatial and spectral domains. Here, we rewrite the problem in a form amenable to maximum-likelihood estimation theory, which we show yields unbiased, minimum-variance estimates of flexural rigidity, initial-loading frac- tion and load correlation, each of those separably resolved with little a posteriori correlation between their estimates. We are also able to separately characterize the isotropic spectral shape of the initial loading processes.Comment: 41 pages, 13 figures, accepted for publication by Geophysical Journal Internationa

The Natural History of Trachoma Infection and Disease in a Gambian Cohort with Frequent Follow-Up

Trachoma is an infectious disease of the eye that causes blindness in many of the poorest parts of the world. In this paper, we use a novel statistical approach to estimate the characteristics of this disease among people living in The Gambia who were examined every 2 weeks over a 6-month period. We found that the typical duration of infection with Chlamydia trachomatis and of clinically active disease were significantly longer than previously estimated. We tested different hypotheses about the natural history of trachoma that explain the relationship between infection and disease observed in the field. We also confirmed that disease lasts significantly longer among young children under 5 years old compared with older children and adults, even after accounting for high rates of re-infection in this age group, consistent with the development of immunity with age. The long duration of infection, especially among younger children, contributes to the persistence and gradual return of trachoma after community-wide treatment with azithromycin. This implies the need for high treatment coverage if infection is to be eliminated from a community, even where the return of infection after treatment is seen to be slow