Representation of hypersonic glide vehicles as fluctuating radar targets

The monostatic RCS of a generic Hypersonic Glide Vehicle (HGV) is presented at S-band and is derived using a Physical Optics (PO) based simulation approach. Target RCS histograms are then produced and used to generate a custom statistical distribution which is subsequently compared against the conventional Swerling models associated with representation of target fluctuation when using the Radar Range Equation (RRE). The accuracy of the Swerling models for this particular target type and frequency band is subsequently discussed

Suicidal ideation among Bangladeshi medical students: a cause for concern?

Suicidal ideation among medical students has become a growing concern, yet it remains a neglected public mental health issue in Bangladesh. This brief paper examines the extant literature on suicide behaviors among Bangladeshi medical students. Data from Bangladesh regarding suicide behaviors among medical students is scarce but of concern. In comparison to university students, the prevalence of medical students' suicidal ideation is significantly higher in Bangladesh. Moreover, medical students' suicide rates globally are reportedly higher than those of the general population (up to 3-5 times higher). During the COVID-19 pandemic, the prevalence rates of suicide behaviors appeared to increase even further. Suggestions are provided for ways to reduce the prevalence of suicide behaviors among Bangladeshi medical students

Editorial: A good sleep: the role of factors in psychosocial health

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Rubisco and carbon-concentrating mechanism co-evolution across chlorophyte and streptophyte green algae.

Green algae expressing a carbon-concentrating mechanism (CCM) are usually associated with a Rubisco-containing micro-compartment, the pyrenoid. A link between the small subunit (SSU) of Rubisco and pyrenoid formation in Chlamydomonas reinhardtii has previously suggested that specific RbcS residues could explain pyrenoid occurrence in green algae. A phylogeny of RbcS was used to compare the protein sequence and CCM distribution across the green algae and positive selection in RbcS was estimated. For six streptophyte algae, Rubisco catalytic properties, affinity for CO2 uptake (K0.5 ), carbon isotope discrimination (δ13 C) and pyrenoid morphology were compared. The length of the βA-βB loop in RbcS provided a phylogenetic marker discriminating chlorophyte from streptophyte green algae. Rubisco kinetic properties in streptophyte algae have responded to the extent of inducible CCM activity, as indicated by changes in inorganic carbon uptake affinity, δ13 C and pyrenoid ultrastructure between high and low CO2 conditions for growth. We conclude that the Rubisco catalytic properties found in streptophyte algae have coevolved and reflect the strength of any CCM or degree of pyrenoid leakiness, and limitations to inorganic carbon in the aquatic habitat, whereas Rubisco in extant land plants reflects more recent selective pressures associated with improved diffusive supply of the terrestrial environment.NE/L002507/1, BB/M007693/1, BB/I024518/1 (NERC, BBSRC and NSF). A Cambridge Trust Vice Chancellor’s award and Lucy Cavendish College, Cambridge, for supporting the PhD scholarship of MMMG. DJO and ECS acknowledge support from (BBSRC; grant number BB/I024488/1)

Suicidal behaviors and associated factors among medical students in Africa: a systematic review and meta-analysis

Background: Suicide behaviors are common among medical students, and the prevalence rates might vary across various regions. Even though various systematic reviews have been conducted to assess suicidal behaviors among medical students in general, no review has ever assessed or carried out a sub-analysis to show the burden of suicidal behaviors among African medical students which was fulfilled in the present study. Method: A systematic review and meta-analysis of prevalence studies among African medical students from PubMed, Scopus, PsycINFO, African Journals Online, and Google Scholar databases. A total of 204 publications were identified. The studies' selection, data extraction, and methodological evaluation were performed, and meta-analysis was performed based on the random effects model. Results: Data were obtained from 14 eligible studies, including 8585 medical students in Africa. The pooled prevalence of lifetime suicidal behaviors was 18.7% for suicidal ideation (95% CI: 14.1%-23.3; I 2 = 94.37%; p < 0.001), 3.8% for suicidal plans (95% CI: 2.7%-4.8%; I 2 = 0.03%; p < 0.001), and 5.5% for suicide attempts (95% CI: 3.8%-7.2%; I 2 = 89.47%; p < 0.001). The factors associated with suicidal ideations were female gender, use of alcohol, depression, and use of khat. Only depression was associated with suicide attempts. Limitations: The review involved few studies, and not all African regions were represented. Conclusion: Suicidal behaviors, particularly suicide attempts, are high among medical students in Africa. However, very few studies are done in the region to clearly quantify the burden and its associated factors

Prevalence of depression in Uganda: a systematic review and meta-analysis

Background: Depression is one of the most studied mental health disorders, with varying prevalence rates reported across study populations in Uganda. A systematic review and meta-analysis was carried out to determine the pooled prevalence of depression and the prevalence of depression across different study populations in the country. Methods: Papers for the review were retrieved from PubMed, Scopus, PsycINFO, African Journal OnLine, and Google Scholar databases. All included papers were observational studies regarding depression prevalence in Uganda, published before September 2021. The Joanna Briggs Institute Checklist for Prevalence Studies was used to evaluate the risk of bias and quality of the included papers, and depression pooled prevalence was determined using a random-effects meta-analysis. Results: A total of 127 studies comprising 123,859 individuals were identified. Most studies were conducted among individuals living with HIV (n = 43; 33.9%), and the most frequently used instrument for assessing depression was the Depression sub-section of the Hopkins Symptom Checklist (n = 34). The pooled prevalence of depression was 30.2% (95% confidence interval [CI]: 26.7–34.1, I2 = 99.80, p<0.001). The prevalence of depression was higher during the COVID-19 pandemic than during the pre-pandemic period (48.1% vs. 29.3%, p = 0.021). Refugees had the highest prevalence of depression (67.6%; eight studies), followed by war victims (36.0%; 12 studies), individuals living with HIV (28.2%; 43 studies), postpartum or pregnant mothers (26.9%; seven studies), university students (26.9%; four studies), children and adolescents (23.6%; 10 studies), and caregivers of patients (18.5%; six studies). Limitation: Significantly high levels of heterogeneity among the studies included. Conclusion: Almost one in three individuals in Uganda has depression, with the refugee population being disproportionately affected. Targeted models for depression screening and management across various populations across the country are recommended

Fear of COVID-19 and its association with mental health-related factors: systematic review and meta-analysis

Background: The severity of COVID-19 remains high worldwide. Therefore, millions of individuals are likely to suffer from fear of COVID-19 and related mental health factors. Aims: The present systematic review and meta-analysis aimed to synthesize empirical evidence to understand fear of COVID-19 and its associations with mental health-related problems during this pandemic period. Method: Relevant studies were searched for on five databases (Scopus, ProQuest, EMBASE, PubMed Central, and ISI Web of Knowledge), using relevant terms (COVID-19-related fear, anxiety, depression, mental health-related factors, mental well-being and sleep problems). All studies were included for analyses irrespective of their methodological quality, and the impact of quality on pooled effect size was examined by subgroup analysis. Results: The meta-analysis pooled data from 91 studies comprising 88 320 participants (mean age 38.88 years; 60.66% females) from 36 countries. The pooled estimated mean of fear of COVID-19 was 13.11 (out of 35), using the Fear of COVID-19 Scale. The associations between fear of COVID-19 and mental health-related factors were mostly moderate (Fisher's z = 0.56 for mental health-related factors; 0.54 for anxiety; 0.42 for stress; 0.40 for depression; 0.29 for sleep problems and –0.24 for mental well-being). Methodological quality did not affect these associations. Conclusions: Fear of COVID-19 has associations with various mental health-related factors. Therefore, programmes for reducing fear of COVID-19 and improving mental health are needed

Measuring health-related quality of life in chronic headache: A comparative evaluation of the Chronic Headache Quality of Life Questionnaire and Headache Impact Test (HIT-6).

OBJECTIVE: To compare the quality and acceptability of a new headache-specific patient-reported measure, the Chronic Headache Quality of Life Questionnaire (CHQLQ) with the six-item Headache Impact Test (HIT-6), in people meeting an epidemiological definition of chronic headaches. METHODS: Participants in the feasibility stage of the Chronic Headache Education and Self-management Study (CHESS) (n = 130) completed measures three times during a 12-week prospective cohort study. Data quality, measurement acceptability, reliability, validity, responsiveness to change, and score interpretation were determined. Semi-structured cognitive interviews explored measurement relevance, acceptability, clarity, and comprehensiveness. RESULTS: Both measures were well completed with few missing items. The CHQLQ's inclusion of emotional wellbeing items increased its relevance to participant's experience of chronic headache. End effects were present at item level only for both measures. Structural assessment supported the three and one-factor solutions of the CHQLQ and HIT-6, respectively. Both the CHQLQ (range 0.87 to 0.94) and HIT-6 (0.90) were internally consistent, with acceptable temporal stability over 2 weeks (CHQLQ range 0.74 to 0.80; HIT-6 0.86). Both measures responded to change in headache-specific health at 12 weeks (CHQLQ smallest detectable change (improvement) range 3 to 5; HIT-6 2.1). CONCLUSIONS: While both measures are structurally valid, internally consistent, temporally stable, and responsive to change, the CHQLQ has greater relevance to the patient experience of chronic headache.Trial registration number: ISRCTN79708100. Registered 16th December 2015, http://www.isrctn.com/ISRCTN79708100

Measuring health-related quality of life in chronic headache:a comparative evaluation of the Chronic Headache Quality of Life Questionnaire and Headache Impact Test (HIT-6)

Objective: To compare the quality and acceptability of a new headache-specific patient-reported measure the Chronic Headache Quality of Life Questionnaire (CHQLQ), with the Headache Impact Test–6 item (HIT-6), in people meeting an epidemiological definition of chronic headaches.Methods: Participants in the feasibility stage of the Chronic Headache Education and Self-management Study (CHESS) (N=130) completed measures three times during a 12-week prospective cohort study. Data quality, measurement acceptability, reliability, validity, responsiveness to change, and score interpretation were determined. Semi-structured cognitive interviews explored measurement relevance, acceptability, clarity, and comprehensiveness.Results: Both measures were well completed with few missing items. The CHQLQ’s inclusion of emotional wellbeing items increased its relevance to participant’s experience of chronic headache. End effects were present at item level only for both measures. Structural assessment supported the three and one-factor solutions of the CHQLQ and HIT-6, respectively. Both the CHQLQ (range 0.87 to 0.94) and HIT-6 (0.90) were internally consistent, with acceptable temporal stability over 2-weeks (CHQLQ range 0.74 to 0.80; HIT-6 0.86). Both measures responded to change in headache-specific health at 12-weeks (CHQLQ smallest detectable change (improvement) range 3 to 5; HIT-6 2.1). Conclusions: While both measures are structurally valid, internally consistent, temporally stable and responsive to change, the CHQLQ has greater relevance to the patient experience of chronic headache. <br/

Stratospheric Ozone Changes From Explosive Tropical Volcanoes: Modeling and Ice Core Constraints

Major tropical volcanic eruptions have emitted large quantities of stratospheric sulphate and are potential sources of stratospheric chlorine although this is less well constrained by observations. This study combines model and ice core analysis to investigate past changes in total column ozone. Historic eruptions are good analogues for future eruptions as stratospheric chlorine levels have been decreasing since the year 2000. We perturb the pre-industrial atmosphere of a chemistry-climate model with high and low emissions of sulphate and chlorine. The sign of the resulting Antarctic ozone change is highly sensitive to the background stratospheric chlorine loading. In the first year, the response is dynamical, with ozone increases over Antarctica. In the high HCl (2 Tg emission) experiment, the injected chlorine is slowly transported to the polar regions with subsequent chemical ozone depletion. These model results are then compared to measurements of the stable nitrogen isotopic ratio, δ15N(NO−3), from a low snow accumulation Antarctic ice core from Dronning Maud Land (recovered in 2016-17). We expect ozone depletion to lead to increased surface ultraviolet (UV) radiation, enhanced air-snow nitrate photo-chemistry and enrichment in δ15N(NO−3) in the ice core. We focus on the possible ozone depletion event that followed the largest volcanic eruption in the past 1000 years, Samalas in 1257. The characteristic sulphate signal from this volcano is present in the ice-core but the variability in δ15N(NO−3) dominates any signal arising from changes in UV from ozone depletion. Prolonged complete ozone removal following this eruption is unlikely to have occurred over Antarctica.National Environment Research Council (NERC) Standard Grant (NE/N011813/1