Background: Turbulence is the leading cause of injury in commercial aviation, and the burden is expected to grow as climate change strengthens the wind shears that generate it. Many such injuries, mostly fractures among cabin crew, follow a potentially preventable sequence in which a hazard is not detected early enough for occupants to be secured. Detection depends on airborne radar and remote-sensing instruments whose design is validated by simulation of electromagnetic wave propagation, and the fidelity of that simulation depends on how faithfully the unbounded atmosphere is represented on a finite grid. This theoretical viewpoint proposes that a specific tool for that truncation, the perfectly matched layer, may be indirectly relevant to passenger and crew safety, and sets out the argument with the underlying mathematics made explicit and accessible. Methods: We present a self-contained account of the perfectly matched layer as a complex coordinate stretching of the governing wave equations. Using analytic continuation into complex coordinates, we derive its frequency-independent attenuation and the stability, discretization and angular limits that bound its accuracy. The work is theoretical: no human-subject data, clinical outcomes, new simulations or operational aviation-system validation are reported. Results: The framework shows why the layer is reflectionless in the continuous limit, why its absorption is frequency independent, and precisely where it degrades. These are the properties that govern the accuracy of the sensor simulations on which radar-based turbulence detection partly rests. We also outline a staged pathway for validation against numerical benchmarks, realistic atmospheric data and existing detection methods. Conclusion: Improved boundary treatment is not a clinical intervention, but may contribute upstream to more reliable hazard detection; any reduction in injuries remains an untested hypothesis. We frame the idea, state its limits honestly, including the radar-invisibility of clear-air turbulence, and invite collaboration between the wave-simulation and aviation-medicine communities.
Background: Hepatitis B virus (HBV) remains an important occupational health concern for healthcare workers, including nursing and midwifery students who may be exposed to blood and body fluids during clinical training. This study aims to assess the associations of attitude, HBV testing and socioeconomic conditions with hepatitis B vaccination among nursing and midwifery students at the University for Development Studies (UDS), Ghana. Methods: An analytical cross-sectional study was conducted among nursing and midwifery students at UDS, Tamale, in June 2023. Of 350 students approached, 306 completed a structured questionnaire. Data were analyzed using partial least squares structural equation modelling (PLS-SEM) in SmartPLS 4.3.1 and complementary ordinary least-squares regression in SPSS. The measurement model was assessed using indicator loadings, Cronbach's alpha, composite reliability, average variance extracted (AVE), and the Fornell-Larcker criterion. Results: Of the 306 respondents, 85.0% had ever tested for HBV, 79.4% reported receiving at least one vaccine dose, and 62.7% reported completing three doses. The PLS-SEM model showed positive associations of attitude (β=0.353, p<0.001), HBV testing (β=0.301, p<0.001), and socioeconomic conditions (β=0.291, p<0.001) with the HBV vaccination construct and explained 76.2% of its variance (R²=0.762). In the complementary regression analysis, the main-effects model explained 72.5% of the variance in vaccination (R²=0.725). Adding interaction terms increased R² to 0.728 (ΔR²=0.003); both HBV testing×socioeconomic conditions (β=0.213, p<0.001) and attitude×HBV testing (β=0.311, p<0.001) were positively associated with vaccination. Conclusion: Attitude, HBV testing and socioeconomic conditions were positively associated with hepatitis B vaccination among the participating students. Interventions that improve access to HBV testing and vaccination and strengthen occupational-risk awareness may support higher vaccination uptake. Because of the cross-sectional design, these associations should not be interpreted as causal effects.
Background: Multiple congenital anomalies are an important cause of perinatal morbidity and mortality, particularly when abnormalities involve several organ systems. Antenatal ultrasonography is essential for early recognition of major structural abnormalities and for appropriate parental counseling. Case presentation: A 33-year-old woman was referred at 34 weeks of gestation for detailed fetal ultrasonography because of a previous intrauterine fetal demise associated with an undiagnosed congenital anomaly. The current pregnancy was complicated by severe polyhydramnios. Ultrasound demonstrated discordant fetal biometry, a large umbilical vein varix, non-visualization of the stomach, collapsed bowel loops, hepatomegaly, a small thoracic cavity, leftward displacement of the heart, clubfoot, and generalized fetal skin edema. The fetal brain and spine appeared normal, whereas facial assessment was limited by fetal position. The combination of severe polyhydramnios and multiple structural abnormalities raised strong suspicion of a severe multisystem congenital anomaly with a poor prognosis. Following delivery, esophageal atresia and severe pulmonary hypoplasia were confirmed, and the neonate died within a few minutes of birth. Conclusion: This case highlights the importance of systematic antenatal anomaly assessment, particularly in pregnancies complicated by severe polyhydramnios and a previous pregnancy affected by congenital anomalies. Early detailed ultrasound examination may facilitate recognition of lethal abnormalities, multidisciplinary counseling, and appropriate pregnancy and perinatal management.
Background: Men with chronic obstructive pulmonary disease (COPD) may underreport mood disturbance and instead present with somatic symptoms. This study aimed to examine the social patterning of sleep disturbance and fatigue as item-level depressive symptoms and their associations with disease burden among men with spirometry-defined COPD. Methods: Data were obtained from 982 men (mean age = 62 years) in the 2007–2012 U.S. National Health and Nutrition Examination Survey; 58% were Non-Hispanic White, 21% Non-Hispanic Black, 9% Mexican American, 7% Other Hispanic and 5% other/multiracial. Logistic regression assessed associations of race/ethnicity, socioeconomic position, lung function, smoking, and multimorbidity with each symptom. Results: Older age was associated with lower odds of sleep disturbance, whereas multimorbidity was associated with higher odds (adjusted OR = 1.62, 95% CI [1.09, 2.42]). Fatigue was associated with socioeconomic position, with higher odds among participants in PIR Category 0 compared with Category 3 (adjusted OR = 2.39, 95% CI [1.51, 3.78]), FEV₁/FVC (adjusted OR = 0.11, 95% CI [0.02, 0.81]), smoking status (overall p = .024), and multimorbidity (OR = 1.52, 95% CI [1.05, 2.20]). Race/ethnicity was associated with fatigue (overall p = .001), but not sleep disturbance (overall p = .071). Conclusion: Sleep disturbance and fatigue showed distinct patterns of association with socioeconomic position and clinical characteristics among men with COPD. Future assessment of these individual depressive symptoms may complement broader depression screening and inform gender-sensitive clinical interventions.
Background: This study examines the prevalence and social patterning of sleep disturbance and fatigue as item-level depressive symptoms among women with chronic obstructive pulmonary disease (COPD). Methods: Data was drawn from 564 women aged 40-79 years (mean age = 62) with spirometry defined COPD in the 2007–2012 U.S. National Health and Nutrition Examination Survey. Logistic regression evaluated associations between age, race/ethnicity, socioeconomic position, smoking, lung function, multi-morbidity, and symptom outcomes. The adjusted regression analyses included 486 participants with complete data. Results: Sleep disturbance was associated with younger age relative to the sample range (40–79 years) (OR = 0.98, 95% CI [0.96, 0.99]) and lower socioeconomic position (aOR = 2.04, 95% CI [1.25, 3.31]), p = .004). Fatigue was associated with younger age (OR = 0.96, 95% CI [0.95, 0.98]), p < .001), lower socioeconomic position (aOR = 2.31, 95% CI [1.40, 3.81], p = .001), and multi-morbidity (≥2 chronic conditions versus 0-1; aOR = 2.16, 95% CI [1.31, 3.58], p = .003). Race/ethnicity, smoking, and lung function were not independently associated with either outcome. Conclusion: Findings suggest that socioeconomic disadvantage and multimorbidity may be important considerations when assessing fatigue and sleep disturbance among women with COPD, supporting a more intersectional approach to symptom assessment and pulmonary rehabilitation.
