Dopant-vacancy cluster formation in germanium

Recent experimental and theoretical studies revealed that dopants in germanium (Ge) cluster with lattice vacancies (V). The existence of these larger clusters has been recently predicted and is important as they can contribute to the low activation of dopants in Ge. With the use of electronic structure calculations we study the binding energies of clusters formed with the association of dopant atoms and vacancies. As an example of the kinetics of such clusters the diffusion of two phosporous-vacancy (P2V) clusters via the ring mechanism of diffusion in predicted. These P2 clusters are important as they can act as precursors for the formation of the larger P3V and P4V clusters. The present study provides information on the structure of clusters and is consistent with recent experimental results, which indicate that the formation of clusters in heavily doped Ge is possible. In agreement with experiment, we predict that the diffusion of P V pairs is retarded by the addition of a further P atom

Test-retest reliability of the Italian version of the M-BACK questionnaire to assess the barriers, attitudes, confidence, and knowledge of mental health staff regarding metabolic health of psychiatric patients

OBJECTIVES:The Metabolic-Barriers, Attitudes, Confidence, and Knowledge Questionnaire (M-BACK) was developed to determine the barriers, attitudes, confidence, and knowledge of mental health practitioners regarding the metabolic health of patients in order to determine the efficacy of targeted training interventions. This study aimed to validate the Italian version of M-BACK questionnaire (M-BACK-IT) and to determine the test-retest reliability. METHODS:The M-BACK questionnaire was translated into Italian and back-translated using an established protocol. In order to determine the test-retest reliability of the instrument, mental health professionals were recruited from a private psychiatric hospital located in northeast Italy and completed the questionnaire on two separate occasions, seven days apart. Intraclass correlation coefficients (ICC) were calculated for the total score, as well as each of the four M-BACK domains. RESULTS:Thirty mental health professionals (4 psychiatrists, 9 psychologists, 12 nurses, and 5 exercise specialists) completed the M-BACK-IT. ICCs ranged from 0.58 to 0.94. CONCLUSIONS:The test-retest reliability of the M-BACK-IT demonstrated comparable results to the English version. The M-BACK-IT is a reliable measure to assess key elements of practitioners' perceptions of the barriers, their knowledge, attitudes, and confidence regarding metabolic monitoring and intervention in people with mental illness

Mechanisms of arsenic clustering in silicon

A model of arsenic clustering in silicon is proposed and analyzed. The main feature of the proposed model is the assumption that negatively charged arsenic complexes play a dominant role in the clustering process. To confirm this assumption, electron density and concentration of impurity atoms incorporated into the clusters are calculated as functions of the total arsenic concentration. A number of the negatively charged clusters incorporating a point defect and one or more arsenic atoms are investigated. It is shown that for the doubly negatively charged clusters or for clusters incorporating more than one arsenic atom the electron density reaches a maximum value and then monotonically and slowly decreases as total arsenic concentration increases. In the case of doubly negatively charged cluster incorporating two arsenic atoms, the calculated electron density agrees well with the experimental data. Agreement with the experiment confirms the conclusion that two arsenic atoms participate in the cluster formation. Among all present models, the proposed model of clustering by formation of doubly negatively charged cluster incorporating two arsenic atoms gives the best fit to the experimental data and can be used in simulation of high concentration arsenic diffusion.Comment: 13 pages, 4 figures. Revised and shortened version of the paper has been published in Phys. Rev. B, Vol.74 (3), art. no. 035205 (2006

A Longitudinal Study of Head Circumference Trajectories in Autism and Autistic Traits

Increased head circumference is an established finding in autism spectrum disorder (ASD); however, it is unclear when this increase occurs, if it persists and whether it manifests across the whole ASD spectrum. Head circumference is a strong predictor of brain size and can therefore provide key insights into brain development in ASD. We used data from the Avon Longitudinal Study of Parents and Children to compare head circumference trajectories from birth to 15 years in children with an ASD diagnosis (N = 78, controls = 6,404) or elevated autistic traits as measured using the Social Communication Disorder Checklist (N = 639, controls = 6,230). Exploratory analyses were conducted in those with ASD and co-morbid cognitive learning needs (CLN). Children with an ASD diagnosis had larger head circumference from birth across childhood and adolescence compared to controls in univariable (B = 0.69, 95% confidence interval [CI]: 0.28-1.09, p = 0.001) and multivariable models (B = 0.38, 95% CI: 0.003-0.75, p = 0.048). Differences were more marked in those with co-morbid CLN. Children with elevated autistic traits had significantly smaller head circumference compared to controls. There was weak evidence of group differences when height was included as a covariate. Head circumference trajectories in ASD deviate from control children and persist until adolescence. Autistic traits were associated with smaller head circumference, suggesting distinct growth trajectories between clinical cases from those with non-clinical traits

Predictors of disengagement from Early Intervention in Psychosis services.

BACKGROUND: The effectiveness of Early Intervention in Psychosis (EIP) services for individuals with a first episode of psychosis (FEP) could be thwarted by high rates of early disengagement.AimsTo investigate which factors predict disengagement with EIP services. METHOD: Using data from a naturalistic cohort of 786 EIP clients in East Anglia (UK), we investigated the association between sociodemographic and clinical predictors and disengagement using univariable and multivariable Cox proportional hazards models. RESULTS: Over half (54.3%) of our sample were discharged before receiving 3 years of EIP care, with 92 (11.7%) participants discharged due to disengagement. Milder negative symptoms, more severe hallucinations, not receiving an FEP diagnosis, polysubstance use and being employed were associated with greater disengagement. CONCLUSIONS: Our findings highlight heterogeneous reasons for disengagement with EIP services. For some patients, early disengagement may hinder efforts to sustain positive long-term EIP outcomes. Efforts to identify true FEP cases and target patients with substance use problems and more severe positive symptoms may increase engagement.Declaration of interestNone

The role of loneliness in the association between chronic physical illness and depressive symptoms among older adults: A prospective cohort study

BACKGROUND: Chronic physical illness increases the risk of subsequent depressive symptoms, but we know little about the mechanisms underlying this association that interventions can target. We investigated whether loneliness might explain associations between chronic illness and subsequent depressive symptoms. METHODS: We used English Longitudinal Study of Ageing data, a prospective cohort of adults over 50. Our exposure was chronic illnesses (wave two) including arthritis, cancer, diabetes, cardiovascular disease, stroke, and chronic obstructive pulmonary disease. Loneliness scores were a mediator on the short University of California, Los Angeles Loneliness Scale at wave three. Depressive symptom scores (outcome) were measured using the Centre for Epidemiologic Studies Depression Scale (wave four). We examined associations of chronic physical illness with loneliness and depressive symptoms in univariable and multivariable regression models. RESULTS: Fully-adjusted models included 2436 participants with the depression outcome and 2052 participants with the loneliness outcome. Chronic physical illness was associated with 21 % (incident rate ratio = 1.21, 95%CI = 1.03–1.42) higher depression scores at follow-up. We found no evidence of an association between chronic physical illness and loneliness and therefore did not proceed to analyses of mediation. LIMITATIONS: More prevalent chronic illnesses could have driven our results, such as cardiovascular disease. CONCLUSIONS: Chronic physical illnesses increase the risk of depressive symptoms in older adults. However, we did not find any that chronic physical illnesses were associated with an increased risk of subsequent loneliness. Therefore, interventions targeting loneliness to reduce depression in older adults with chronic physical illness may be insufficient

Prevalence of purging at age 16 and associations with negative outcomes among girls in three community-based cohorts.

The comorbidity of purging behaviours, such as vomiting, inappropriate use of laxatives, diuretics or slimming medications, has been examined in literature. However, most studies do not include adolescents, individuals who purge in the absence of binge eating, or those purging at subclinical frequency. This study examines the prevalence of purging among 16-year-old girls across three countries and their association with substance use and psychological comorbidity

Family functioning but not social capital is associated with better mental health in adolescents affected by violence and displacement by armed conflict in Colombia

Background: The effect of the Colombian armed conflict on the mental health of adolescents is still poorly understood. Aims: Given social interventions are most likely to inform policy, we tested whether two potential intervention targets, family functioning and social capital, were associated with mental health in Colombian adolescents, and whether this was moderated by experience of violence and displacement. Methods: We examined the cross-sectional association between family functioning, cognitive social capital, structural social capital and 12-month prevalence of Composite International Diagnostic Interview (CIDI) diagnosed psychiatric disorder, using data on 12 to 17-year-old adolescents (N = 1,754) from the 2015 National Mental Health Survey of Colombia, a nationally representative epidemiological study. We tested whether associations survived cumulative adjustment for demographic confounders, experience of non-specific violence and harm and displacement by armed conflict. Results: Neither structural nor cognitive social capital were associated with better mental health. Better family functioning was associated with reduced risk of poor mental health in an unadjusted analysis (OR 0.90 [0.85–0.96]), and after cumulative adjustments for demographic confounders (OR 0.91 [0.86–0.97]), non-specific violence and harm (OR 0.91 [0.86–0.97]) and social capital variables (OR 0.91 [0.85–0.97]). In the final model, each additional point on the family APGAR scale was associated with a 9% reduced odds of any CIDI diagnosed disorder in the last 12 months. Conclusions: Better family functioning was associated with better mental health outcomes for all adolescents. This effect remained present in those affected by the armed conflict even after accounting for potential confounders

The association between loneliness and depressive symptoms among adults aged 50 years and older: a 12-year population-based cohort study

Background: Loneliness is experienced by a third of older adults in the UK and is a modifiable potential risk factor for depressive symptoms. It is unclear how the association between loneliness and depressive symptoms persists over time, and whether it is independent of related social constructs and genetic confounders. We aimed to investigate the association between loneliness and depressive symptoms, assessed on multiple occasions during 12 years of follow-up, in a large, nationally representative cohort of adults aged 50 years and older in England. / Methods: We did a longitudinal study using seven waves of data that were collected once every 2 years between 2004 and 2017, from adults aged 50 years and older in the English Longitudinal Study of Ageing (ELSA). The exposure was loneliness at baseline (wave two), measured with the short 1980 revision of the University of California, Los Angeles Loneliness Scale (R-UCLA). The primary outcome was a score indicating severity of depression measured at six subsequent timepoints (waves three to eight), using the eight-item version of the Centre for Epidemiologic Studies Depression Scale (CES-D). Analyses were linear multilevel regressions, before and after adjusting for social isolation, social support, polygenic risk scores, and other sociodemographic and health-related confounders. The secondary outcome was depression diagnosis, measured using a binary version of the CES-D. / Findings: 4211 (46%) of 9171 eligible participants had complete data on exposure, outcome, and confounders, and were included in our complete case sample. After all adjustments, a 1-point increase in loneliness score was associated with a 0·16 (95% CI 0·13–0·19) increase in depressive symptom severity score (averaged across all follow-ups). We estimated a population attributable fraction for depression associated with loneliness of 18% (95% CI 12–24) at 1 year of follow-up and 11% (3–19) at the final follow-up (wave eight), suggesting that 11–18% of cases of depression could potentially be prevented if loneliness were eliminated. Associations between loneliness and depressive symptoms remained after 12 years of follow-up, although effect sizes were smaller with longer follow-up. / Interpretation: Irrespective of other social experiences, higher loneliness scores at baseline were associated with higher depression symptom severity scores during 12 years of follow-up among adults aged 50 years and older. Interventions that reduce loneliness could prevent or reduce depression in older adults, which presents a growing public health problem worldwide. / Funding: National Institute on Aging and a consortium of UK Government departments coordinated by the National Institute for Health Research

Depression and self-harm from adolescence to young adulthood in sexual minorities compared to heterosexuals: a population-based cohort study

BACKGROUND: There are few population-based cohort studies of the emergence, development, and persistence of mental health problems in sexual minorities compared with heterosexuals. We compared trajectories of depressive symptoms in sexual-minority adolescents and heterosexual adolescents from when they were aged 10 years to 21 years, and examined self-harm at ages 16 years and 21 years. // METHODS: The study included 4828 adolescents born between April 1, 1991, and Dec 31, 1992, from the Avon Longitudinal Study of Parents and Children birth cohort (Bristol, UK) who reported their sexual orientation when aged 16 years. Depressive symptoms were assessed with the short Mood and Feelings Questionnaire (sMFQ) at seven timepoints between ages 10 years and 21 years. A self-harm questionnaire was completed at ages 16 years and 21 years. Analyses were linear multilevel models with growth curves (depressive symptoms), logistic multilevel models (self-harm in the previous year at ages 16 years and 21 years), and multinomial regression (lifetime self-harm with and without suicidal intent at age 21 years). // FINDINGS: At age 10 years, depressive symptoms were higher in sexual minorities (mean sMFQ 4·58 [SD 3·59]) than in heterosexuals (3·79 [3·36]) and increased with age to a larger extent. Depressive symptoms increased at each timepoint by 0·31 sMFQ points in hetereosexuals (95% CI 0·27–0·34), and by 0·49 sMFQ points in sexual minorities (0·40–0·59). Sexual-minority adolescents were more likely than heterosexual adolescents to report self-harm in the previous year at ages 16 years and 21 years (adjusted odds ratio 4·23, 95% CI 2·90–6·16), with no evidence that this estimate decreased with age (p=0·80). When aged 21 years, sexual minorities were 4·53 (95% CI 3·02 to 6·78) times more likely to report lifetime self-harm (ie, on at least one previous occasion) with suicidal intent than heterosexuals. // INTERPRETATION: Mental health disparities between heterosexuals and sexual minorities are present early in adolescence and increase throughout the school years, persisting to young adulthood. Prevention of these mental health problems and early intervention must be a priority. // FUNDING: Medical Research Council, Wellcome Trust