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exoALMA. XVII. Characterizing the Gas Dynamics around Dust Asymmetries
Get PDFThe key planet-formation processes in protoplanetary disks remain an active matter of research. One promising
mechanism to radially and azimuthally trap millimeter-emitting dust grains, enabling them to concentrate and grow
into planetesimals, is anticyclonic vortices. While dust observations have revealed crescent structures in several
disks, observations of their kinematic signatures are still lacking. Studying the gas dynamics is, however, essential
to confirm the presence of a vortex and understand its dust trapping properties. In this work, we make use of the
high-resolution and sensitivity observations conducted by the exoALMA large program to search for such
signatures in the ¹²CO and ¹³CO molecular line emission of four disks with azimuthal dust asymmetries:
HD 135344B, HD 143006, HD 34282, and MWC 758. To assess the vortex features, we constructed an analytical
vortex model and performed hydrodynamical simulations. For the latter, we assumed two scenarios: a vortex
triggered at the edge of a dead zone and of a gap created by a massive embedded planet. These models reveal a
complex kinematical morphology of the vortex. When compared to the data, we find that none of the sources show
a distinctive vortex signature around the dust crescents in the kinematics. HD 135344B exhibits a prominent
feature similar to the predictions from the simulations, thus making this the most promising target for sensitive
follow-up studies at higher resolution and in particular with less abundant molecules at higher resolution and
sensitivity to trace closer to the disk midplane
Experience and acceptability of a guided self-help intervention for anxiety for individuals with Huntington’s disease (GUIDE-HD trial): A qualitative study
Get PDFPeople with Huntington’s disease (HD) commonly experience anxiety, yet access to psychological interventions remains limited. Guided self-help is a low-cost, scalable, evidence-based approach with the potential to improve access to psychological support. This qualitative study aimed to explore participants’ experience of GUIDE-HD, a remote guided self-help intervention designed to address anxiety in people with HD based on cognitive behavioural therapy and acceptance and commitment therapy, by examining: (i) the acceptability of the intervention, (ii) any perceived benefits or challenges, and (iii) ways to enhance its relevance and accessibility for people with HD (pwHD). Qualitative individual semi-structured interviews were conducted with nine pwHD and three carers and analysed using framework analysis. Three overarching themes emerged: (1) A therapeutic journey for people with and affected by HD; (2) Mechanisms of benefit; (3) Experiencing various gains. Participants valued the intervention’s relevance, structure, accessibility, personalization and facilitation. Reported gains extended beyond reduced anxiety to increased acceptance of the realities of living with and managing the condition and better relationships. While a number of limitations should be considered, such as the sample size and its predominant female representation, the GUIDE-HD intervention was acceptable and showed promise as a tailored psychological approach for pwHD
Centuries of compounding human influence on Amazonian forests
Get PDFRecent evidence suggests that the ecological footprints of pre-Columbian Indigenous peoples in Amazonia persist in modern forests. Ecological impacts resulting from European colonization c. 1550 CE and the Amazonian Rubber Boom c. 1850 to 1920 CE are largely unexplored but could be important additive influences on forest structure and tree species composition. Using environmental niche models, we show the highest probabilities of pre-Columbian and colonial occupation sites, and hence human-induced ecological influences, occurred in forests along rivers. In many areas, the predicted pre-Columbian and colonial distributions overlap spatially with the potential for superimposed ecological influences. Environmental gradients are known to structure Amazonian vegetation composition, but they are also strong predictors of past human influence, both spatially and temporally. Our comparisons of model outputs with relative abundances of Amazonian tree species suggest that pre-Columbian and colonial-period ecological legacies are associated with modern forest composition
Collaborative research networks as a strategy to synthesize knowledge of Amazonian biodiversity
Get PDFThe Amazon region is critical for maintaining global biodiversity and mitigating climate change; however, it faces escalating threats from deforestation and habitat degradation. Addressing these threats requires evidence-based strategies grounded in investments in science, technology, innovation and collaborative research. The Brazilian National Institute of Science and Technology (INCT) programme plays a central role in advancing scientific and technological progress by establishing collaborative research networks across diverse fields and regions. In this context, we present the INCT in Synthesis of Amazonian Biodiversity (INCT-SynBiAm) as a case study, illustrating how research networks can promote diversity in academia and enhance our understanding of biodiversity in hyperdiverse tropical regions. The SynBiAm network integrates 47 academic and non-academic institutions from Brazil and abroad. Its key objectives are to establish and expand a collaborative initiative for research synthesis in Amazonia, deepen our understanding of biodiversity patterns, threats and drivers in forest and freshwater ecosystems, inform environmental and educational practices and policies, and train future educators, decision-makers and scientists committed to the Amazon’s conservation and sustainability. We outline the INCT programme and demonstrate how the INCT-SynBiAm network can achieve these goals, providing a model for future collaborative initiatives aimed at addressing socio-ecological challenges in tropical regions
Combining Machine-Learning Assessment of Multiple MRI Pathologies and Clinical Phenotypes for Predicting Joint Replacement in Knee Osteoarthritis: Data From the Osteoarthritis Initiative
No full textObjective
Artificial intelligence offers opportunities for timesaving assessments of multiple pathologies in large magnetic resonance imaging (MRI) data sets in knee osteoarthritis (KOA). This study evaluated their prevalence within pre-defined clinical phenotypes and their predictive value for knee replacement (KR).
Design
Baseline MRIs (n = 8,667) from the Osteoarthritis Initiative were analyzed using a machine-learning (ML) algorithm. The presence of pathologies (menisci, anterior cruciate, medial collateral ligaments, cartilage, etc.) was assessed in previously identified phenotypic clusters (a post-traumatic, metabolic, and age-defined phenotype). The value of both, cluster allocation and joint pathology for KR prediction was evaluated using supervised ML models and time-dependent receiver operating characteristic curves.
Results
Compared to the population average, the metabolic cluster had a higher prevalence of cartilage lesions, while the post-traumatic one had more medial meniscal damage. Random forest models showed the best prediction (area under the curve 0.837, test set at 2 years). The top predictors for KR were meniscal position (relative to the border of the tibial plateau), severe joint effusion, medial femorotibial cartilage lesions, and metabolic phenotype. These features defined patients at high risk of KR with an estimated KR rate at 5 years of 10% vs 3% in the high- and low-risk groups based on a predictive risk score including all analyzed structures.
Conclusions
This ML-enabled assessment of multiple MRI pathologies in a large KOA data set highlights the importance of meniscal pathologies and markers of inflammation, in addition to cartilage assessments and clinical information for patient stratification and improved prediction of KOA progression to KR
Global, Regional, and National Burden of Cardiovascular Diseases and Risk Factors in 204 Countries and Territories, 1990-2023
Get PDFBackground: Cardiovascular diseases (CVDs) are the leading cause of mortality and are among the foremost causes of disability globally. CVD burden has continued to increase in most countries since 1990, with trends driven by changing exposures to harmful risk factors, population growth, and population aging. Objectives: We report estimates of global, national, and subnational CVD burden, including 18 subdiseases and 12 associated modifiable risk factors. We analyzed change in CVD burden from 1990 to 2023 and identified drivers of change including population growth, population aging, and risk factor exposure. Methods: The Global Burden of Disease (GBD) 2023 study, a multinational collaborative research study, quantified burden due to 375 diseases including CVD burden and identified drivers of change from 1990 to 2023 using all available data and statistical models. GBD 2023 estimated the population-level burden of diseases in 204 countries and territories from 1990 to 2023. Results: CVDs were the leading cause of disability-adjusted life years (DALYs) and deaths estimated in the GBD. As of 2023, there were 437 million (95% UI: 401 to 465 million) CVD DALYs globally, a 1.4-fold increase from the number in 1990 of 320 million (292 to 344 million). Ischemic heart disease, intracerebral hemorrhage, ischemic stroke, and hypertensive heart disease were the leading cardiovascular causes of DALYs in 2023 globally. As of 2023, age-standardized CVD DALY rates were highest in low and low-middle Socio-demographic Index (SDI) settings and lowest in high SDI settings. The number of CVD deaths increased globally from 13.1 million (95% UI: 12.2 to 14.0 million) in 1990 to 19.2 million (95% UI: 17.4 to 20.4 million) in 2023. The number of prevalent cases of CVD more than doubled since 1990, with 311 million (95% UI: 294 to 333 million) prevalent cases of CVD in 1990 and 626 million (95% UI: 591 to 672 million) prevalent cases in 2023 globally. A total of 79.6% (95% UI: 75.7% to 82.5%) of CVD burden is attributable to modifiable risk factors 347 million [95% UI: 318 to 373 million] DALYs in 2023). Globally, high systolic blood pressure, dietary risks, high low-density lipoprotein cholesterol, and air pollution were the modifiable risks responsible for most attributable CVD burden in 2023. Since 1990, changes in exposure to modifiable risk factors have had mixed effects on CVD burden, with increases in high body mass index, high fasting plasma glucose, and low physical activity leading to higher burden, while reductions in tobacco usage have mitigated some of these increases. Population growth and population aging were the main drivers of the increasing burden since 1990, adding 128 million (95% UI: 115 to 139 million) and 139 million (95% UI: 126 to 151 million) CVD DALYs to the increase in CVD burden since 1990. Conclusions: CVD remains the leading cause of disease burden and death worldwide with the greatest burden in low, low-middle, and middle SDI regions. Large variation exists in CVD burden even for countries at similar levels of development, a gap explained substantially by known, modifiable risk factors that are inadequately controlled. The decades-long increase in CVD burden was the result of population growth, population aging, and increased exposure to a subset of risk factors led by metabolic risks. Countries will need to adopt effective health system and public health strategies if they are to progress in achieving global goals to reduce the burden of CVD
Role of recruitment bias in stepped-wedge cluster randomised controlled trials:a systematic review
Get PDFObjectives Increased popularity of stepped-wedge cluster randomised trials (SW-CRT) highlights the importance of understanding and appropriate mitigation of sources of bias within this trial design. While current evidence suggests that ‘conventional’ cluster randomised controlled trials (RCTs) are at a higher risk of recruitment bias than individually randomised trials, this review aims to estimate the risk of recruitment bias in SW-CRTs. Design Systematic review with search conducted on four databases. Risk of bias (RoB) was assessed using subdomain 1a (randomisation process) and 1b (timing of identification or recruitment of participants) of the Cochrane RoB tool 2.0 (extension for cluster RCTs). Data sources MEDLINE, Embase, CINAHL, Cochrane Library were searched on 9 February 2024. Eligibility criteria for selecting studies SW-CRTs published in 2023 were included. Data extraction and synthesis Two independent reviewers screened and extracted all eligible papers. RoB was assessed with the Cochrane RoB tool. Results Overall, 808 papers were screened, and 64 studies were included in the review. Most studies were deemed to have a high RoB (n=35, 55%), some concerns were noticed in 20 studies (31%), and 9 (14%) were considered to have a low RoB. The description of the randomisation process in the included papers was sometimes poorly reported (in 15 studies (23%) problems with the randomisation process were identified), and 21 studies (33%) had issues with sampling strategy (recruiting participants after randomisation by unmasked staff). Conclusions The review revealed that SW-CRTs are prone to recruitment bias, but the risks are comparable to cluster RCTs. When SW-CRTs are unable to recruit prior to randomisation, mitigation strategies could be implemented to reduce bias. A separate tool for RoB assessment in SW-CRTs is required to address the complexities of this trial design
Search for single production of vector-like quarks decaying into W(ℓν)b in pp collisions at √s=13 TeV with the ATLAS detector
Get PDFN2 fixation is linked to the ability to encroach in African savanna trees
Get PDF1. Encroachment is a globally ubiquitous phenomenon, characterised by increasing indigenous tree densities in savanna and grassland. Encroachment has been attributed to rising atmospheric CO2 concentrations fertilising tree growth and shifting the competitive balance between trees and grasses. However, only a subset of savanna tree species are currently described as encroachers, raising the hypothesis that CO2 responsiveness differs among species. Within southern African savannas, encroachment is driven primarily by nitrogen (N2)-fixing species, implying the CO2 response may be mediated via traits that enhance plant-available N.
2. Using an open-topped chamber system, we experimentally manipulated atmospheric CO2 concentrations and soil moisture for 12 savanna tree species (six encroachers and six non-encroachers) under ambient (a)CO2 (~397.9 ppm) or elevated (e)CO2 (~545.1 ppm) treatments and water limited or well-watered soil moisture treatments. We measured N-dynamics traits including nodule mass fraction (NMF), leaf δ15N, stem δ15N, and percentage of N derived from fixation (%Ndfa).
3. We found that encroachers and non-encroachers differ in short-term N-dynamics but share similar long-term N allocation strategies. Encroachers exhibited lower leaf δ15N, indicating greater utilisation of N2 fixation products to meet immediate short-term protein synthesis. Long-term N allocation strategies (NMF, stem δ15N, and %Ndfa) were similar between encroachers and non-encroachers, with plants fixing more N2 under the eCO2 and well-watered treatment. In encroachers, leaf and stem δ¹⁵N were unrelated, in contrast to the positive relationship in non-encroachers, pointing to distinct tissue-level N allocation, possibly reflecting differential N utilisation and retention.
4. We demonstrate the significance of N2 fixation in mediating the CO2 responsiveness of encroaching savanna trees. N2 fixation increases plant-available N, likely enabling encroachers to meet immediate N demands even under water limitation and increasing CO2. The potential feedback loop, where eCO2 enhances photosynthesis, facilitating greater C allocation for N2 fixation, helps to explain the ecological success of the subset of species driving encroachment under increased atmospheric CO2
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