We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Patients with posttraumatic stress disorder (PTSD) exhibit smaller regional brain volumes in commonly reported regions including the amygdala and hippocampus, regions associated with fear and memory processing. In the current study, we have conducted a voxel-based morphometry (VBM) meta-analysis using whole-brain statistical maps with neuroimaging data from the ENIGMA-PGC PTSD working group.
Methods
T1-weighted structural neuroimaging scans from 36 cohorts (PTSD n = 1309; controls n = 2198) were processed using a standardized VBM pipeline (ENIGMA-VBM tool). We meta-analyzed the resulting statistical maps for voxel-wise differences in gray matter (GM) and white matter (WM) volumes between PTSD patients and controls, performed subgroup analyses considering the trauma exposure of the controls, and examined associations between regional brain volumes and clinical variables including PTSD (CAPS-4/5, PCL-5) and depression severity (BDI-II, PHQ-9).
Results
PTSD patients exhibited smaller GM volumes across the frontal and temporal lobes, and cerebellum, with the most significant effect in the left cerebellum (Hedges’ g = 0.22, pcorrected = .001), and smaller cerebellar WM volume (peak Hedges’ g = 0.14, pcorrected = .008). We observed similar regional differences when comparing patients to trauma-exposed controls, suggesting these structural abnormalities may be specific to PTSD. Regression analyses revealed PTSD severity was negatively associated with GM volumes within the cerebellum (pcorrected = .003), while depression severity was negatively associated with GM volumes within the cerebellum and superior frontal gyrus in patients (pcorrected = .001).
Conclusions
PTSD patients exhibited widespread, regional differences in brain volumes where greater regional deficits appeared to reflect more severe symptoms. Our findings add to the growing literature implicating the cerebellum in PTSD psychopathology.
To assess whether universal masking during the COVID-19 pandemic reduced neonatal acquisition of S. aureus.
Study design:
We performed a retrospective cohort study of neonates admitted to a level three regional NICU for three years before and after implementation of universal masking for the COVID-19 pandemic. Multivariable proportional hazards regression models evaluated the effect of masking on time-to-acquisition of methicillin-resistant and methicillin-sensitive S. aureus (MRSA and MSSA) while adjusting for fixed and time-varying neonatal characteristics.
Results:
We analyzed 2,728 neonates, 1,446 pre-pandemic and 1,282 post-pandemic; 84.9% were inborn, with mean gestational age of 34 weeks and 6 days (SD = 4.2) and mean birthweight of 2,500 grams (SD = 975). The mean number of screening cultures per neonate was 3.07 (SD = 3.31). When adjusting for covariates, universal masking was associated with decreased acquisition of MRSA (hazard ratio =0.43 (95% CI: 0.19–0.99), p = 0.04) but not MSSA (HR = 1.27 (95% CI: 00.87–1.85), p = 0.21). Among covariates, airway devices and maternal S. aureus status were associated with S. aureus acquisition.
Conclusions:
Universal masking decreased the rate of NICU MRSA acquisition by 60% while MSSA acquisition was unchanged. Masking may reduce MRSA spread via colonized healthcare personnel while MSSA may be more likely to be acquired from parental skin-to-skin contact and was thus unaffected by masking.
We present the first radio–continuum detection of the circumstellar shell around the well-known WN8 type Wolf-Rayet star WR16 at 943.5 MHz using the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey. At this frequency, the shell has a measured flux density of 72.2$\pm$7.2 mJy. Using previous Australia Telescope Compact Array (ATCA) measurements at 2.4, 4.8, and 8.64 GHz, as well as the Evolutionary Map of the Universe (EMU) observations of the star itself, we determine a spectral index of $\alpha\,=\,+0.74\pm0.02$, indicating thermal emission. We propose that the shell and star both exhibit thermal emission, supported by the its appearance in near-infrared and H$\alpha$ observations. The latest Gaia parallax is used to determine a distance of 2.28$\pm$0.09 kpc. This star is well known for its surrounding circular nebulosity, and using the distance and an angular diameter of $8.^{\prime}42$, we determine the shell size to be 5.57$\pm$0.22 pc. We use the Gaia proper motion (PM) of WR16 to determine peculiar velocities of the star as $V_{\alpha}(pec) =$ –45.3$\pm$5.4 km s$^{-1}$ and $V_{\delta}(pec) =$ 22.8$\pm$4.7 km s$^{-1}$, which indicates that the star is moving in a north-west direction, and translates to a peculiar tangential velocity to be 50.7$\pm$6.9 km s$^{-1}$. We also use these proper motion (PM) to determine the shell’s origin, estimate an age of $\sim 9500\pm 1300$ yr, and determine its average expansion velocity to be $280\pm40$ km s$^{-1}$. This average expansion velocity suggests that the previous transitional phase is a Luminous Blue Variable (LBV) phase, rather than a Red Super Giant (RSG) phase. We also use the measured flux at 943.5 MHz to determine a mass-loss rate of $1.753\times 10^{-5}\,{\rm M}_\odot\,$yr$^{-1}$, and use this to determine a lower-limit on ionising photons of $N_{UV} \gt 1.406\times 10^{47}\,\textit{s}^{-1}$.
This study evaluated the impact of four cover crop species and their termination timings on cover crop biomass, weed control, and corn yield. A field experiment was arranged in a split-plot design in which cover crop species (wheat, cereal rye, hairy vetch, and rapeseed) were the main plot factor, and termination timings [4, 2, 1, and 0 wk before planting corn (WBP)] was the subplot factor. In both years (2021 and 2022), hairy vetch produced the most biomass (5,021 kg ha–1) among cover crop species, followed by cereal rye (4,387 kg ha–1), wheat (3,876 kg ha–1), and rapeseed (2,575 kg ha–1). Regression analysis of cover crop biomass with accumulated growing degree days (AGDDs) indicated that for every 100 AGDD increase, the biomass of cereal rye, wheat, hairy vetch, and rapeseed increased by 880, 670, 780, and 620 kg ha–1, respectively. The density of grass and small-seeded broadleaf (SSB) weeds at 4 wk after preemergence herbicide (WAPR) application varied significantly across termination timings. The grass and SSB weed densities were 56% and 36% less at 0 WBP compared with 2 WBP, and 67% and 61% less compared with 4 WBP. The sole use of a roller-crimper did not affect the termination of rapeseed at 0 WBP and resulted in the least corn yield (3,046 kg ha–1), whereas several different combinations of cover crops and termination timings resulted in greater corn yield. In conclusion, allowing cover crops to grow longer in the spring offers more biomass for weed suppression and impacts corn yield.
Distinguishing early domesticates from their wild progenitors presents a significant obstacle for understanding human-mediated effects in the past. The origin of dogs is particularly controversial because potential early dog remains often lack corroborating evidence that can provide secure links between proposed dog remains and human activity. The Tumat Puppies, two permafrost-preserved Late Pleistocene canids, have been hypothesized to have been littermates and early domesticates due to a physical association with putatively butchered mammoth bones. Through a combination of osteometry, stable isotope analysis, plant macrofossil analysis, and genomic and metagenomic analyses, this study exploits the unique properties of the naturally mummified Tumat Puppies to examine their familial relationship and to determine whether dietary information links them to human activities. The multifaceted analysis reveals that the 14,965–14,046 cal yr BP Tumat Puppies were littermates who inhabited a dry and relatively mild environment with heterogeneous vegetation and consumed a diverse diet, including woolly rhinoceros in their final days. However, because there is no evidence of mammoth consumption, these data do not establish a link between the canids and ancient humans.
Recent changes to US research funding are having far-reaching consequences that imperil the integrity of science and the provision of care to vulnerable populations. Resisting these changes, the BJPsych Portfolio reaffirms its commitment to publishing mental science and advancing psychiatric knowledge that improves the mental health of one and all.
Edited by
David Mabey, London School of Hygiene and Tropical Medicine,Martin W. Weber, World Health Organization,Moffat Nyirenda, London School of Hygiene and Tropical Medicine,Dorothy Yeboah-Manu, Noguchi Memorial Institute for Medical Research, University of Ghana,Jackson Orem, Uganda Cancer Institute, Kampala,Laura Benjamin, University College London,Michael Marks, London School of Hygiene and Tropical Medicine,Nicholas A. Feasey, Liverpool School of Tropical Medicine
Since the beginning of the HIV epidemic, Kaposi’s sarcoma (KS) and aggressive B-cell non-Hodgkin lymphoma (NHL) have been recognized features of acquired immunodeficiency syndrome (AIDS). Over ensuing years, epidemiological studies in people living with HIV (PLWH) demonstrated this population is at increased risk for a variety of other cancers (Yarchoan & Uldrick 2018). For the estimated 26 million PLWH in sub-Saharan Africa (SSA), cancer is a leading cause of morbidity and mortality (Sengayi et al. 2016).
Dementia affects millions globally, with a subset of cases potentially reversible. This study evaluates the incidence, clinical markers and treatment outcomes of reversible dementias (ReDem).
Method:
This retrospective study included 370 ReDem cases from 1810 dementia patients. The ReDem cohort was split into potentially reversible dementias (PRD) and dual etiology (DE) groups. PRD encompassed secondary, potentially treatable dementia conditions, while DE included primary degenerative dementia (DD) with ≥1 uncontrolled comorbidity or new disease that worsened symptoms.
Results:
ReDem cases comprised 20.4% (n = 370 out of 1810) of dementia patients, with ReDem patients being younger (mean 56.2 vs. 61.9 years, p < 0.001) and exhibiting shorter illness durations than DD patients (p < 0.001). Key red flags, including young age (<45 years) at onset (DD = 8.6% vs. ReDem = 18.1%), fluctuation in symptoms (DD = 3.4% vs. ReDem = 11.6%), rapid cognitive decline (DD = 6.9% vs. ReDem = 18.4), high-risk exposures (DD = 0.1% vs. ReDem = 0.8%), high-risk behavior (DD = 0.1% vs. ReDem = 2.4%) and incongruent neuropsychological findings(DD = 1.0% vs. 12.7%), were significantly more frequent in ReDem cases (p < 0.05). Odds increased with each red flag present (≥1: OR = 5.94; ≥2: OR = 20.69; ≥3: OR = 25.14, p < 0.05). Reversible etiologies included immune (20.0%), neuroinfectious (6.6%), psychiatric (7.6%), nutritional/metabolic (10.5%), neurosurgical (14.6%) and other causes (12.2%). Of the 41% (152/370) followed, 19 expired, 63.9% (85/133) reported subjective improvement, and 31.6% (42/133) showed clinical dementia rating improvement.
Discussion and Conclusion:
This large-scale study underscores the importance of comprehensive diagnostic evaluations for ReDem. Identifying and treating reversible conditions and comorbidities in DD can improve patient outcomes, emphasizing the need for thorough evaluations in memory clinics and targeted interventions in dementia care.
The stars of the Milky Way carry the chemical history of our Galaxy in their atmospheres as they journey through its vast expanse. Like barcodes, we can extract the chemical fingerprints of stars from high-resolution spectroscopy. The fourth data release (DR4) of the Galactic Archaeology with HERMES (GALAH) Survey, based on a decade of observations, provides the chemical abundances of up to 32 elements for 917 588 stars that also have exquisite astrometric data from the Gaia satellite. For the first time, these elements include life-essential nitrogen to complement carbon, and oxygen as well as more measurements of rare-earth elements critical to modern-life electronics, offering unparalleled insights into the chemical composition of the Milky Way. For this release, we use neural networks to simultaneously fit stellar parameters and abundances across the whole wavelength range, leveraging synthetic grids computed with Spectroscopy Made Easy. These grids account for atomic line formation in non-local thermodynamic equilibrium for 14 elements. In a two-iteration process, we first fit stellar labels to all 1 085 520 spectra, then co-add repeated observations and refine these labels using astrometric data from Gaia and 2MASS photometry, improving the accuracy and precision of stellar parameters and abundances. Our validation thoroughly assesses the reliability of spectroscopic measurements and highlights key caveats. GALAH DR4 represents yet another milestone in Galactic archaeology, combining detailed chemical compositions from multiple nucleosynthetic channels with kinematic information and age estimates. The resulting dataset, covering nearly a million stars, opens new avenues for understanding not only the chemical and dynamical history of the Milky Way but also the broader questions of the origin of elements and the evolution of planets, stars, and galaxies.
Adolescent and parental perceptions of the Fontan Udenafil Exercise Longitudinal Assessment Randomised Controlled Trial (FUEL) and its open-label extension were examined, to identify factors affecting future research participation.
Methods:
A validated survey was administered at two time points to adolescents (12–19 years) and their parents to assess likes/dislikes of study participation, research team, study burden and benefits. A 5-point Likert scale (strongly disagree [−2] to strongly agree [ + 2]) was used, and scores were averaged. Regression models explored potential predictors. Open-ended questions queried the most/least appealing aspects of participation and considerations for future research.
Results:
Among 250 FUEL participants at 14 centres, 179 adolescent and 183 parent surveys were completed at T1 (6 months after randomisation). Perceptions of research participation were generally positive: 1.35 ± 0.45 for adolescents; 1.56 ± 0.38 (p < 0.001) for parents. There were no significant differences between females vs. males. Themes from open-ended responses included liking to help others and themselves, liking the study team, and disliking study burden. Adolescents liked the compensation and disliked study-related testing. At T2 (end of open-label extension study), 121 adolescents and 114 parents responded. Perception scores remained high at 1.39 ± 0.51 for adolescents and 1.58 ± 0.37 for parents (p = 0.001). There were no significant gender differences in perceptions between adolescents, but mothers had slightly better perceptions than fathers (p = 0.004).
Conclusions:
Perceptions of research were positive and slightly better for parents. Study teams and compensation were key contributors to positive perceptions. Study burden and testing were viewed less favourably. Future studies should consider families’ preferences and potential barriers to participation.
An important component of post-release monitoring of biological control of invasive plants is the tracking of species interactions. During post-release monitoring following the initial releases of the weevil Ceutorhynchus scrobicollis Nerenscheimer and Wagner (Coleoptera: Curculionidae) on garlic mustard, Alliaria petiolata (Marschall von Bieberstein) Cavara and Grande (Brassicaceae), in Ontario, Canada, we identified the presence of larvae of the tumbling flower beetle, Mordellina ancilla Leconte (Coleoptera: Mordellidae), in garlic mustard stems. This study documents the life history of M. ancilla on garlic mustard to assess for potential interactions between M. ancilla and C. scrobicollis as a biological control agent. Garlic mustard stems were sampled at eight sites across southern Ontario and throughout the course of one year to record the prevalence of this association and to observe its life cycle on the plant. We found M. ancilla to be a widespread stem-borer of late second–year and dead garlic mustard plants across sampling locations. This is the first host record for M. ancilla on garlic mustard. The observed life cycle of M. ancilla indicates that it is unlikely to negatively impact the growth and reproduction of garlic mustard and that it is unlikely to affect the use of C. scrobicollis as a biological control agent.
It remains unclear which individuals with subthreshold depression benefit most from psychological intervention, and what long-term effects this has on symptom deterioration, response and remission.
Aims
To synthesise psychological intervention benefits in adults with subthreshold depression up to 2 years, and explore participant-level effect-modifiers.
Method
Randomised trials comparing psychological intervention with inactive control were identified via systematic search. Authors were contacted to obtain individual participant data (IPD), analysed using Bayesian one-stage meta-analysis. Treatment–covariate interactions were added to examine moderators. Hierarchical-additive models were used to explore treatment benefits conditional on baseline Patient Health Questionnaire 9 (PHQ-9) values.
Results
IPD of 10 671 individuals (50 studies) could be included. We found significant effects on depressive symptom severity up to 12 months (standardised mean-difference [s.m.d.] = −0.48 to −0.27). Effects could not be ascertained up to 24 months (s.m.d. = −0.18). Similar findings emerged for 50% symptom reduction (relative risk = 1.27–2.79), reliable improvement (relative risk = 1.38–3.17), deterioration (relative risk = 0.67–0.54) and close-to-symptom-free status (relative risk = 1.41–2.80). Among participant-level moderators, only initial depression and anxiety severity were highly credible (P > 0.99). Predicted treatment benefits decreased with lower symptom severity but remained minimally important even for very mild symptoms (s.m.d. = −0.33 for PHQ-9 = 5).
Conclusions
Psychological intervention reduces the symptom burden in individuals with subthreshold depression up to 1 year, and protects against symptom deterioration. Benefits up to 2 years are less certain. We find strong support for intervention in subthreshold depression, particularly with PHQ-9 scores ≥ 10. For very mild symptoms, scalable treatments could be an attractive option.
Inadequate recruitment and retention impede clinical trial goals. Emerging decentralized clinical trials (DCTs) leveraging digital health technologies (DHTs) for remote recruitment and data collection aim to address barriers to participation in traditional trials. The ACTIV-6 trial is a DCT using DHTs, but participants’ experiences of such trials remain largely unknown. This study explored participants’ perspectives of the ACTIV-6 DCT that tested outpatient COVID-19 therapeutics.
Methods:
Participants in the ACTIV-6 study were recruited via email to share their day-to-day trial experiences during 1-hour virtual focus groups. Two human factors researchers guided group discussions through a semi-structured script that probed expectations and perceptions of study activities. Qualitative data analysis was conducted using a grounded theory approach with open coding to identify key themes.
Results:
Twenty-eight ACTIV-6 study participants aged 30+ years completed a virtual focus group including 1–4 participants each. Analysis yielded three major themes: perceptions of the DCT experience, study activity engagement, and trust. Participants perceived the use of remote DCT procedures supported by DHTs as an acceptable and efficient method of organizing and tracking study activities, communicating with study personnel, and managing study medications at home. Use of social media was effective in supporting geographically dispersed participant recruitment but also raised issues with trust and study legitimacy.
Conclusions:
While participants in this qualitative study viewed the DCT-with-DHT approach as reasonably efficient and engaging, they also identified challenges to address. Understanding facilitators and barriers to DCT participation and DHT interaction can help improve future research design.
Objectives/Goals: Despite the acknowledgment of post-Ebola syndrome (PES), young EVD survivors have received little attention. The mechanistic drivers and long-term consequences of PES and EVD early in life are unknown. We aim to define PES presentations in pediatric EVD survivors and propose potential mechanistic factors contributing to PES in young people. Methods/Study Population: Here we focus on physical health outcomes in an ongoing cohort study assessing mental and physical health in pediatric EVD survivors (age Results/Anticipated Results: 671 participants were enrolled between 2021 and 2022 (Infected: n = 226, Affected: n = 207, and Control: n = 238). Groups were similar in sex distribution (52.7%, 54.0%, and 53.8% female, respectively) and mean age, although the Infected group was slightly older (14.6 y) than the Affected (13.5 y) and Control groups (14.1 y), a difference unlikely to be clinically significant. Notably, the EVD Infected group exhibited a higher burden of symptoms, with significant findings in cardiac, MSK, ophthalmologic, and “ear, nose, and throat” systems. Principal component analysis showed differential patterns of sequelae across the groups, primarily defined by MSK. Discussion/Significance of Impact: PES is heterogeneous in pediatric EVD survivors. EVD Affected children exhibit a similar yet distinct pattern of clinical sequelae indicating ecological factors impact sequelae and raising questions about the mechanistic drivers of PES in children. Potential mechanisms include inflammation or accelerated aging and immune dysfunction.
Spectra have been obtained with the multi-fibre instrument 2dF on the Anglo-Australian Telescope of 89 candidate main sequence stars in the globular cluster M55 (NGC 6809). Radial velocities and Gaia proper motions confirm 72 candidates as cluster members. Among these stars one stands out as having a substantially stronger G-band (CH) than the rest of the member sample. The star is a dwarf carbon star that most likely acquired the high carbon abundance ([C/Fe] $\approx$ 1.2 $\pm$ 0.2) via mass transfer from a $\sim$1$-$3 M$_{\odot}$ binary companion (now a white dwarf) during its AGB phase of evolution. Interestingly, M55 also contains a CH-star that lies on the cluster red giant branch – the low central concentration/low density of this cluster presumably allows the survival of binaries that would otherwise be disrupted in denser systems. The existence of carbon stars in six other globular clusters is consistent with this hypothesis, while the origin of the carbon-enhanced star in M15 (NGC 7078) is attributed to a merger process similar to that proposed for the origin of the carbon-rich R stars.
Polar ring galaxies (PRGs) are a unique class of galaxies characterised by a ring of gas and stars orbiting nearly orthogonal to the main body. This study delves into the evolutionary trajectory of PRGs using the exemplary trio of NGC 3718, NGC 2685, and NGC 4262. We investigate the distinct features of PRGs by analysing their ring and host components to reveal their unique characteristics through spectral energy distribution (SED) fitting. Using CIGALE, we performed SED fitting to independently analyse the ring and host spatially resolved regions, marking the first decomposed SED analysis for PRGs, which examines stellar populations using high-resolution observations from AstroSat UVIT at a resolved scale. The UV-optical surface profiles provide an initial idea that distinct patterns in the galaxies, with differences in FUV and NUV, suggest three distinct stages of ring evolution in the selected galaxies. The study of resolved-scale stellar regions reveals that the ring regions are generally younger than their host galaxies, with the age disparity progressively decreasing along the evolutionary sequence from NGC 3718 to NGC 4262. Star formation rates (SFR) also exhibit a consistent pattern, with higher SFR in the ring of NGC 3718 compared to the others, and a progressive decrease through NGC 2685 and NGC 4262. Finally, the representation of the galaxies in the HI gas fraction versus the NUV–$\text r$ plane supports the idea that they are in three different evolutionary stages of PRG evolution, with NGC 3718 in the initial stage, NGC 2685 in the intermediate stage, and NGC 4262 representing the final stage. This study concludes that PRGs undergo various evolutionary stages, as evidenced by the observed features in the ring and host components. NGC 3718, NGC 2685, and NGC 4262 represent different stages of this evolution, highlighting the dynamic nature of PRGs and emphasising the importance of studying their evolutionary processes to gain insights into galactic formation and evolution.
This is a unique case of microbubbles incidentally found on echocardiogram in a child with unpalliated CHD. The microbubbles were found in both the venous and arterial circulations and spontaneously resolved. A detailed evaluation was done to identify the source of air in the circulation. The child did have concurrent necrotising enterocolitis, and it was felt that the bubbles were secondary to this and intestinal translocation of air.
We present a chemo-dynamical study conducted with 2dF$+$AAOmega of $\sim 6\,000$Gaia DR3 non-variable candidate metal-poor stars that lie in the direction of the Galactic plane. Our spectral analysis reveals 15 new extremely metal-poor (EMP) stars, with the lowest metallicity at $\left[\text{Fe/H}\right] = -4.0 \pm 0.2$ dex. Two of the EMP stars are also carbon enhanced, with the largest enhancement of $\left[\text{C/Fe}\right] = 1.3 \pm 0.1$ occurring in a dwarf. Using our $\left[\text{C/Fe}\right]$ results, we demonstrate that the number of carbon-depleted stars decreases with lower metallicities, and the fraction of carbon-enhanced stars increases, in agreement with previous studies. Our dynamical analysis reveals that the fraction of prograde and retrograde disk stars, defined as $z_{\mathrm{max}} \lt 3$ kpc, with $J_{\phi}/J_{\mathrm{tot}} \gt 0.75$ and $J_{\phi}/J_{\mathrm{tot}} \lt -0.75$, respectively, changes as metallicities decrease. Disk stars on retrograde orbits make up $\sim 10$% of all the stars in our sample with metallicities below $-2.1$ dex. Interestingly, the portion of retrograde disk stars compared with the number of kinematically classified halo stars is approximately constant at $4.6$% for all metallicities below $-1.5$ dex. We also see that $J_{\phi}$ increases from $380 \pm 50$ to $1320 \pm 90$ km s$^{-1}$ kpc across metallicity range $-1.5$ to $-1.1$, consistent with the spin-up of the Galactic disk. Over the metallicity range $-3.0 \lt \left[\text{Fe/H}\right] \lt -2.0$, the slopes of the metallicity distribution functions for the prograde and retrograde disk stars are similar and comparable to that for the halo population. However, detailed chemical analyses based on high-resolution spectra are needed to distinguish the accreted versus in situ contributions. Finally, we show that our spectroscopic parameters reveal serious systematics in the metallicities published in recent studies that apply various machine learning techniques to Gaia XP spectra.
This research tackles the challenge of enhancing the engineering properties of kaolinite-rich clay through innovative and sustainable treatment approaches. The main aim was to investigate the effects of nano-materials such as calcium carbonate and silica on the plasticity, strength, compressibility, and microstructural behavior of kaolin. The experimental process involved blending kaolin with varying concentrations (0.5–2% by dry weight) of calcium carbonate and silica. Standard laboratory tests, such as Atterberg limits, unconfined compressive strength (UCS), and one-dimensional consolidation tests, were performed to evaluate changes in plasticity, mechanical strength, and compressibility. Microstructural analyses using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) provided insights into the structural and surface modifications of the treated clay. The findings demonstrated a notable reduction in the plasticity index of kaolin as the nano-material content increased, with the optimal dosage identified at ~1% for both nano-materials. At this dosage, the UCS of the treated clay increased threefold, attributed to the formation of a nano-crystalline gel and improved particle interactions. Consolidation tests revealed a significant decrease in the compression index, while the hydraulic conductivity remained similar to that of untreated kaolin. Microstructural analysis confirmed the development of an aggregated-flocculated structure, enhanced pore connectivity, and increased surface area in the clay nano-composite. In summary, the incorporation of calcium carbonate and silica particles significantly enhanced the engineering characteristics of kaolinite-rich clay, highlighting their promise as sustainable alternatives for clay improvement. These results pave the way for broader applications of nano-materials in geotechnical engineering.
There is an urgent need to understand explanatory factors of poor mental health before (pre-) and during (peri-) the COVID-19 pandemic in university students, especially those from underrepresented and minority groups.
Aims
To examine potential differences and explanatory factors for psychological distress, clinical risk and impact of problems on academic outcomes pre- and peri-pandemic in university students.
Method
A repeated cross-sectional design was used with routine data between August 2018 and July 2022 at the registration stage from a student counselling and mental health service at a UK university. Wilcoxon signed-rank tests were used to examine pre- and peri-pandemic differences in outcomes. Unadjusted and adjusted linear regression models were conducted to assess potential explanatory factors for poor outcomes.
Results
A total of 9517 university students had completed sociodemographic and outcome data and were included in analysis. Psychological distress and impact of problems on academic outcomes were not significantly different between pre- and peri-pandemic groups. Clinical risk was significantly higher in the pre-pandemic than peri-pandemic group. Potential explanatory factors for poorer outcomes included being younger, female or non-binary/genderqueer, sexual minority, from a minority ethnic group, having home fee status and having a disability registration.
Conclusions
Poor student mental health profiles and related explanatory factors may not have changed drastically between pre- and peri-pandemic. Longitudinal methods and intersectional approaches should be used in future research. Further understanding of how universities and student mental health services can most efficiently and effectively support the mental health of university students is crucially warranted.