Quantum field theory predicts a nonlinear response of the vacuum to strong electromagnetic fields of macroscopic extent. This fundamental tenet has remained experimentally challenging and is yet to be tested in the laboratory. A particularly distinct signature of the resulting optical activity of the quantum vacuum is vacuum birefringence. This offers an excellent opportunity for a precision test of nonlinear quantum electrodynamics in an uncharted parameter regime. Recently, the operation of the high-intensity Relativistic Laser at the X-ray Free Electron Laser provided by the Helmholtz International Beamline for Extreme Fields has been inaugurated at the High Energy Density scientific instrument of the European X-ray Free Electron Laser. We make the case that this worldwide unique combination of an X-ray free-electron laser and an ultra-intense near-infrared laser together with recent advances in high-precision X-ray polarimetry, refinements of prospective discovery scenarios and progress in their accurate theoretical modelling have set the stage for performing an actual discovery experiment of quantum vacuum nonlinearity.

We examined the association between influenza vaccination policies at acute care hospitals and influenza vaccination coverage among healthcare personnel for the 2021–22 influenza season. Mandatory vaccination and masking for unvaccinated personnel were associated with increased odds of vaccination. Hospital employees had higher vaccination coverage than licensed independent practitioners.

Antibiotic utilization for respiratory conditions (AXR) is a new Healthcare Effectiveness Data & Information Set ® (HEDIS®) measure designed to complement disease-specific metrics to improve outpatient antibiotic prescribing. Unique challenges include ensuring clinicians understand the metric and establishing appropriate goals within different health systems and service lines. Successful implementation requires awareness of the metric’s limitations and may be enhanced by co-reporting with condition-specific antibiotic use metrics to prioritize local interventions.

Item factor analysis has a rich tradition in both the structural equation modeling and item response theory frameworks. The goal of this paper is to demonstrate a novel combination of various Markov chain Monte Carlo (MCMC) estimation routines to estimate parameters of a wide variety of confirmatory item factor analysis models. Further, I show that these methods can be implemented in a flexible way which requires minimal technical sophistication on the part of the end user. After providing an overview of item factor analysis and MCMC, results from several examples (simulated and real) will be discussed. The bulk of these examples focus on models that are problematic for current “gold-standard” estimators. The results demonstrate that it is possible to obtain accurate parameter estimates using MCMC in a relatively user-friendly package.

We develop simple noniterative estimators of the polyserial correlation coefficient. A general relationship between the polyserial correlation and the point polyserial correlation is exploited to give extensions of Pearson's, Brogden's, and Lord's biserial estimators to the multicategory setting. The small sample and asymptotic properties of these estimators are studied in some detail. A comparison with maximum likelihood estimates shows that Lord's polyserial estimator is fairly efficient across three probability models.

Female athletes are increasingly participating in sport during pregnancy and returning postpartum. However, similar to the Sex Data Gap in sport and exercise research(1), there is limited evidence to support athletes during this life stage(2) especially as it relates to nutrition. Therefore, as optimal nutrition is essential for long-term maternal and child health, the aim of this study was to investigate specific wants, needs and behaviours in relation to nutrition during pregnancy and postpartum return to sport in athletes.

King’s College London provided ethical approval (Ref: LRU/DP-23/24-41676) and the study was pre-registered (https://doi.org/10.17605/OSF.IO/NCSZK). An exploratory cross-sectional online survey is being conducted and dissemination is occurring during April and May 2024. Primary variables are assessed using researcher developed and validated measures and included pregnancy and postpartum nutritional support needs, supplement use, athlete level, performance changes and sociodemographic characteristics. Residents of the UK or ROI, ≥ 18 years old, trained and/or competed as an athlete prior to and/or during pregnancy within the last eight years are eligible. All data was summarised using IBM SPSS Statistics. Due to the exploratory nature of the survey, preliminary descriptive evidence is shown and comparisons between groups (e.g. athlete level, region, number of pregnancies) will be presented.

35 eligible athletes (UK: 24 (68.6%); ROI: 11 (31.4%)) from 14 team and individual sports have completed the survey. Average age of participants was 34.2±3.2 and 32 (91.4%) had ≥1 child. 9 participants (25.7%) were currently pregnant, and 7 (20%) had retired due to pregnancy. Only 9 participants (25.7%) received any nutrition advice during pregnancy, and, of the postpartum participants, one participant (3.8%) received nutrition advice during the postpartum period. During pregnancy, participants reported wanting to receive advice from NHS Midwives, Obstetricians and Gynaecologists (37.7%) and fellow athletes who’ve previously experienced pregnancy (21%).

Whereas postpartum advice was preferable from NHS Midwives, Obstetricians and Gynaecologists (37.1%), sports-specific nutritionist/dietitian (37.1%) and general

nutritionist/dietitian (37.1%). During pregnancy, 28 participants (80%) reported wanting athletespecific nutrition advice related training needs during pregnancy and 19 participants (54.3%) reported wanting more information about pregnancy-specific supplement intake (e.g. folic acid). Postpartum, 22 participants (62.9%) reported wanting athlete-specific nutrition advice related training needs during postpartum and returning to sport and 20 participants (57.1%) reported wanting more information about breast or mixed feeding. The top listed challenges to returning to sport postpartum were childcare provisions (94.3%), infant feeding practices (85.7%) and sleep (82.9%).

The preliminary findings revealed that pregnant/postpartum athletes want further advice in areas such as nutrition advice specific to being an athlete and training during pregnancy and postpartum, pregnancy supplement intake, and infant feeding practices. These areas require further investigation so pregnant and postpartum athlete needs can be better met.

While clinical research intends to improve health outcomes for all, access to research participation is often limited and inequitable. Geographic proximity is a recognized barrier, thus, systemic infrastructure solutions through federal programs including General Clinical Research Centers and Clinical and Translational Science Awards have sought to improve accessibility. Even with such support, academic medical centers often have limited clinical research-dedicated space apart from shared exam rooms in difficult-to-navigate hospitals or clinics. In 2019, the Duke University School of Medicine looked beyond its medical center campus to identify free-standing sites within Durham communities for participant study visits. Catalyzed by the COVID-19 pandemic, Duke Research at Pickett, a 22 000-square-foot building with a laboratory, 30 exam rooms, and on-site parking, opened in October 2020 to support vaccine and treatment trials. Upon the lifting of many COVID-19 restrictions, and in partnership with the Research Equity and Diversity Initiative (READI) Community Advisory Council, the building was transformed to encourage community gatherings, education, and training programs. To date, Duke Research at Pickett has hosted 2692 participants in 78 research trials and 14 community-engaged activities.

Restriction of energy intake is an effective strategy for achieving body mass loss(1). However, it leads to gastrointestinal appetite hormonal changes, which are expected to enhance hunger, reduce satiety, and possibly impair the ability to comply with prescribed intervention(2). Exercise interventions, on the other hand, did not modify gastrointestinal appetite hormones(3) and there is some evidence that postprandial appetite hormone responses after a low carbohydrate-high fat meal (LCHF) are more favorable than after high carbohydrate-low fat meal (HCLF) meal (4). This study investigated how energy-restricted diets based on LCHF and HCLF meals and combined with exercise affect body weight, and gastrointestinal appetite hormones and explored the relationship between body mass changes and changes in gastrointestinal appetite hormones.

Twenty-seven overweight and obese females (age: 35 ± 9.35 years, BMI: 31.64 ± 5.08 kg/m2) completed a randomized parallel design study and underwent a 4-week intervention consisting of brisk walking combined with either consumption of calorie-restricted HCLF or LCHF diet. Participants underwent a 5-hour experimental trial before and after the interventions, which included body weight measurements and fasting and postprandial blood sample collection for gastrointestinal appetite hormone measurements.

Both interventions significantly reduced body mass (HCLF group, −2.1 ± 1.7 Kg: LCHF group, -1.7 ± 1.7 Kg, P < 0.05 for both groups), but changes between the groups were not significant (P>0.05). Body mass changes were individual and ranged from -0.4 kg to −5.3 kg and from +1 kg to −4.4 kg in the HCLF and LCHF groups, respectively. The interventions had no impact on mean values of time- averaged postprandial concentrations of ghrelin, PYY, and GLP-1 but there was large individual variability in changes of these hormones. Results combined from both groups revealed that changes in ghrelin ranged from +549.3 to -407.7 pg/ml, in PYY from −132.5 to + 96.4 pg/ml and in GLP-1 from −6.6 to +19.5 pg/ml. Correlation, investigated on the data from both groups combined, between changes in body mass and changes in ghrelin (r = −0.18, P= 0.41), PYY (r = −0.04, P =0.87), and GLP-1 (r = 0.11, P = 0.64) were not significant.

In conclusion, the extent of body mass loss during interventions based on restricted energy intake diets combined with exercise is not related to the carbohydrate and fat content of the diet. Our findings also suggest that the success of body mass loss cannot be predicted by changes in postprandial concentrations of gastrointestinal appetite hormones.

Spray drying dilute suspensions of bentonitic montmorillonite produces a powder that shows totally random orientation of the crystallites within a sample large enough to diffract X-rays. The powder is collected by an electrostatic precipitator and can be handled in the normal mounting processes without introducing preferred orientation. Electron micrographs show this powder to be composed on a small scale of thin, crumpled, and rolled films. The extremely small montmorillonite crystallites that make up the film are oriented with [001] directions perpendicular to the film surface. Orientation within the plane of the film is random as shown by selected area electron diffraction. Crumpling and rolling of the film is sufficient to make the orientation of [001] directions random in three dimensions in a large sample when X-ray diffraction is registered.

The X-ray diffraction patterns all show diffraction maxima (both hk and 00l), and their relative intensities with respect to each other can be determined. The line broadening of the 06 and the 003 peaks was studied. The average crystallite size as calculated from the line broadening varied from six to eleven unit layers thick for four bentonitic montmorillonites. The average lateral dimension of crystallites varied from 140 Å to 250 Å. Ratios of lateral dimensions to thickness varied from 2.3 to 3.4.

Background: After a transient ischemic attack (TIA) or minor stroke, the long-term risk of subsequent stroke is uncertain. Methods: Electronic databases were searched for observational studies reporting subsequent stroke during a minimum follow-up of 1 year in patients with TIA or minor stroke. Unpublished data on number of stroke events and exact person-time at risk contributed by all patients during discrete time intervals of follow-up were requested from the authors of included studies. This information was used to calculate the incidence of stroke in individual studies, and results across studies were pooled using random-effects meta-analysis. Results: Fifteen independent cohorts involving 129794 patients were included in the analysis. The pooled incidence rate of subsequent stroke per 100 person-years was 6.4 events in the first year and 2.0 events in the second through tenth years, with cumulative incidences of 14% at 5 years and 21% at 10 years. Based on 10 studies with information available on fatal stroke, the pooled case fatality rate of subsequent stroke was 9.5% (95% CI, 5.9 – 13.8). Conclusions: One in five patients is expected to experience a subsequent stroke within 10 years after a TIA or minor stroke, with every tenth patient expected to die from their subsequent stroke.