324139 research outputs found
Sort by
The role of age in the relationship between brain structure and cognition: moderator or confound?
Get PDFUnderstanding how differences in brain structure relate to differences in cognition across the lifespan is essential for addressing age-related cognitive decline. Since age is strongly associated with both brain structure and cognition, predictive models often risk simply capturing age effects. To mitigate this risk, deconfounding is typically applied to remove the effects of age. Here, beyond treating age as a confound, we treat it as a moderator by estimating brain-cognition associations separately across age groups. This captures age-stratified changes in how brain structure and cognitive performance are statistically connected. For this view to hold, variations in brain structure linked to differences in cognitive performance in older subjects (eg related to disease) would differ from those in younger subjects. Using structural brain imaging data from the UK Biobank we found an asymmetry in generalisability: models trained on younger subjects successfully predicted cognition in older subjects, but models trained on older subjects failed to generalize to younger individuals. These findings reveal a trade-off between model specificity and generalisability, suggesting the optimal approach—whether age-specific or pooled—depends on the research or clinical goal for the target population
A randomized assessment of the impact of ‘Those Nerdy Girls’ newsletters on adult vaccination outcomes
Get PDFAdult vaccine-preventable infectious diseases contribute substantial burden each year, and vaccine uptake remains suboptimal. As digital health communication grows, digital newsletters may represent a scalable, low-cost tool to promote vaccination. We conducted a randomized prospective study to evaluate the impact of digital newsletters on subscribers’ knowledge, attitudes, and behaviors regarding four adult vaccines: respiratory syncytial virus (RSV), influenza, shingles, and COVID-19. Between November 2023 and January 2024, half of subscribers to the Those Nerdy Girls (TNG) Substack newsletter received additional vaccine-focused newsletters, while the other half received only the standard twice-weekly newsletters. Pre- and post-intervention online surveys assessed vaccine knowledge, attitudes, and behaviors among adult subscribers who consented to participate. Across 1,327 pre-intervention and 1,208 post-intervention participants, knowledge gains were observed for RSV and shingles vaccines in the intervention group compared with controls, while knowledge of influenza and COVID-19 vaccines did not improve. Attitudes toward vaccination were generally positive at baseline and showed no significant intervention effects across vaccine types. Likelihood of vaccination increased for influenza, COVID-19, and RSV overall during the study period, but only influenza vaccination showed a significantly greater increase in the intervention group relative to controls. No significant effects were found for shingles vaccination. These results indicated that digital newsletters can improve knowledge and, in some contexts, support uptake, but knowledge gains did not consistently translate into changes in attitudes or behaviors. Findings highlighted the limitations of knowledge-deficit models for adult vaccination promotion. Digital newsletters should be considered as one component of broader public health strategies, particularly when paired with approaches that address logistical access, trust, and social norms
Global Hydroclimatic Controls on Multithread River Dynamics
Get PDFPlain Language Summary: Earth's largest rivers typically split flow into many interconnected pathways, called threads. Multithread rivers change their planform shape in response to variations in water flow and sediment delivery. However, studying these rivers has been difficult due to limited long‐term observations and analytical tools to accurately characterize their evolution. We analyzed 38 years of satellite images alongside river flow data from 97 multithread rivers worldwide. We found that increased dimensionless discharge values—defined as the ratio of long‐term average discharge to bankfull capacity of a river to carry flow—are associated with an increase in the number of active threads, emergence of one or more threads that carry majority of flow, and a slowdown of river evolution. This result highlights that flow variability, when viewed through the lens of channel morphology, is the dominant control on multithread river dynamics. We also find that multithread rivers in cold climates evolve more slowly compared to their counterparts in other climate zones likely due to the influence of permafrost. With climate change increasing flow variability, we predict that multithread rivers will increase their thread count and become more dynamic globally, potentially impacting livelihoods and ecosystems in river corridors
Toward Social (Non)Recognition through Political Rhetoric: The Stigmatized Cases of India, the Federal Republic of Germany, and Iran
Get PDFExisting literature treats the corrected identity of stigmatized states as i) nonstigmatized, ii) a parolee whose past crimes are not forgotten, and iii) a legitimate identity that fails to get reintegrated with the group of the stigmatizers. However, there remains little focus in studying how noncompliant states arrive at each of these identity dynamics of social (non)recognition from the stigmatizers. In addressing this gap, this article argues that corrective identity typologies are dependent on the ways in which the stigmatized convinces the stigmatizer of the former’s new identity. To do so, and using the empirical cases of India, the Federal Republic of Germany, and Iran, this article develops a political rhetoric typology employed by the stigmatized in terms of forensic rhetoric (using a track record of past compliant acts in wanting justice for oneself), compliant rhetoric (acceptance of previous incongruent acts and practices), and stasis rhetoric (contestation practices over long periods of time). Alongside rooting this typology in the anxious relationship between the stigmatized and the stigmatizer, this article contributes to the scholarship on stigma management and the literature on political rhetoric
Takotsubo Syndrome Presenting as ST-Elevation Myocardial Infarction With Concomitant Persistent High-Grade AV Block Requiring Cardiac Resynchronisation Therapy Pacemaker
Get PDFTakotsubo syndrome (TTS), also known as stress-induced cardiomyopathy or apical ballooning syndrome, is increasingly recognised as an acute myocardial ischemic syndrome primarily involving transient microvascular dysfunction rather than epicardial coronary occlusion and characterised by transient left ventricular dysfunction. Patients are predominantly postmenopausal women and may clinically mimic acute coronary syndrome, including ST-elevation myocardial infarction (STEMI) as well as non-ST-elevation myocardial infarction (NSTEMI). While TTS may coexist with obstructive coronary artery disease (CAD), the hallmark feature is a mismatch between the severity of wall motion abnormalities and the distribution of any coronary lesions. We present a postmenopausal lady who presented as a presumed STEMI but was eventually diagnosed to have takotsubo cardiomyopathy. She developed a persistent high-grade AV block with poor ejection fraction and was subsequently implanted with a cardiac resynchronisation therapy pacemaker (CRT-P)
Distributionally robust adversarial attacks with mirrored loss
Get PDFWe approach the problems of constructing adversarial attacks under a distributionally robust, data-driven adversarial attack to binary classification by minimizing the probability of accurate classification as a proxy of maximizing misclassification, a metric we term mirrored loss. We show that a relaxation of this reformulation results in a convex adversarial problem for linear binary classifiers, that allows for a tractable problem formulation. In addition, we extend the approach, of minimizing a mirrored loss function, to non-convex settings, such as Convolutional Neural Networks (CNNs), for multi-class classification. Through experiments on the MNIST dataset, we demonstrate that our method outperforms other adversarial attacks by achieving higher misclassification rates with lower data distortion even in the non-convex case. These findings suggest that our approach provides a more effective and efficient adversarial attack framework, with potential applications beyond binary classification
Methodological quality of studies designed to create twin-specific neonatal anthropometric charts: a systematic review
No full textBackground: Twin foetuses show a physiologically slower growth rate in the third trimester compared to singletons. Therefore, it has been suggested that the anthropometric evaluation of twins at birth should be performed using twin-specific charts. To be reliable, anthropometric charts need to fulfil certain methodological criteria. Objective: To systematically review studies which developed neonatal twin-specific anthropometric charts and assess their methodological quality. Data sources: A comprehensive search was conducted across Cinahl, Embase, Global Index Medicus, Pubmed, Scopus, Web of Science, Google Scholar, and relevant preprint repositories, followed by a predefined snowballing search. Study selection and data extraction: Two reviewers independently screened studies for eligibility, selecting those which developed crosssectional anthropometric charts for twins at birth, published since January 1990. Papers were excluded if they did not use anthropometric measurements at birth to construct charts. Two reviewers independently extracted data and performed quality assessment with a 16-item grading system. Results: Sixty-eight studies were included. All but one constructed reference, not standard, charts. Most studies did not meet the quality criteria: only 9% were prospectively designed, 34% reliably estimated 3 gestational age, 19% reported standardized instruments, 28% described measurement techniques, and 26% did not stratify centiles by sex. Conclusions: This review reveals considerable methodological limitations in existing twin-specific neonatal anthropometric charts
Using a causal effect network approach to quantify the impact of ENSO teleconnections on summer monsoon precipitation over the Himalayas and key regional circulations
Get PDFWe perform a causal analysis to quantify the direct causal links on intraseasonal time‐scales associated with the influence of El Niño–Southern Oscillation (ENSO) teleconnections on summer monsoon Himalayan precipitation (SMHP) and two key coupled regional circulations, which are the monsoon Hadley circulation (MHC) and the component of the regional Walker circulation (RWC) over the Himalayas. This is achieved by using a causal effect network (CEN) approach to show graphically the direction and strength of linkages between four monthly climate indices representing ENSO, SMHP, RWC, and MHC from 1940 to 2022 with a time lag of one month. Depending on the complexity of the CENs constructed, the results show causal effect (CE) values as follows: (i) ENSO to SMHP of − 0.33 to − 0.44 (i.e., a one standard deviation increase in ENSO causes a decrease in SMHP of between − 0.33 and − 0.44 standard deviations with a lag of one month), (ii) ENSO to MHC of − 0.12 to − 0.15, and (iii) ENSO to RWC of − 0.17 to − 0.20. These are interpreted as an increase in ENSO (analogous to the El Niño phase) causing a substantial decrease in Himalayan precipitation, as well as weakening the key regional circulations. Further results showed CE values from MHC to SMHP of 0.32 to 0.43 and from RWC to SMHP of 0.30 to 0.37. These are interpreted as a strengthening of both the regional Walker circulation and the monsoon Hadley circulation causing a substantial increase in Himalayan precipitation. Finally, the approach was used to clarify the coupled interactions between RWC and MHC, which showed a CE value of 0.14 to 0.17 from RWC to MHC and from MHC to RWC. This suggests positive feedback between the two regional circulations
Comparing Cross‐Sectional and Longitudinal Study Designs for Accurate Viral Dynamics Estimation: Insights From the NBA Cohort Data
Get PDFViral load data provide critical insights into host‐pathogen interactions and guide clinical and public health decisions. Because frequent testing is often infeasible, viral dynamics models are used to reconstruct infection trajectories, but optimal sampling strategies remain unclear. We compared two approaches for collecting SARS‐CoV‐2 viral load data: cross‐sectional sampling (one measurement at symptom onset) and longitudinal sampling (every 3 days after onset) under constraints on the total number of tests and tests per individual. A viral dynamics model was first fitted to data from the National Basketball Association cohort, and the estimated parameters were treated as ground truth. Synthetic data were then generated under each sampling design, refitted, and evaluated for accuracy in estimating viral load over 30 days, peak viral load, peak time, and viral shedding duration. Longitudinal sampling consistently yielded lower root mean squared error and narrower one standard deviation interval than cross‐sectional sampling. Peak timing and viral shedding duration were unbiased under both designs, but cross‐sectional designs underestimated peak viral load and produced wider one standard deviation intervals. Coverage of viral load estimates was markedly higher for longitudinal designs (> 0.90) compared with cross‐sectional ones (~0.10). Accuracy and coverage exceeded 0.96 even with just two tests per individual, with little additional benefit from more tests. In conclusion, longitudinal sampling—despite limited data—substantially improves accuracy and precision of viral load estimation compared with cross‐sectional designs. These findings highlight efficient strategies for study design and resource allocation in infectious disease research
Social inequalities in patient outcomes after total hip replacement surgery for osteoarthritis in England: A population-based cohort study of the National Joint Registry
Get PDFBackground: Reducing health inequalities is of national importance. Total hip replacement (THR) is a commonly used elective surgical procedure. Few studies have examined area-level inequalities for a wide range of outcomes following THR. The aim of this study is to compare area-level socioeconomic differences in outcomes following primary THR surgery for osteoarthritis in England. Methods and findings: This is a population-based prospective cohort study of the National Joint Registry (NJR). Data from the NJR were linked to national mortality, Hospital Episode Statistics and Patient Reported Outcome Measures (PROMs) databases for England from 2007 to 2017 with follow-up to 2023 for outcomes, for patients aged 50 years and over with osteoarthritis. Outcomes of 90-day mortality; 5-year revision rate; 6-month health complications; 1-year rehospitalisation and reoperation for orthopaedic indications; and patient-reported Oxford Hip Score (OHS), post-THR surgery were examined by area-level Index of Multiple Deprivation quintiles. Modified Poisson regression was adjusted for patient age, sex, body mass index, pre-operative physical state and comorbidity. Among 448,184 patients with primary THR, mean age was 70 years (standard deviation: 9 years) and 61% were women. Patients from the most deprived group were more likely to die within 90 days of the operation compared to the least deprived group (adjusted rate ratio, RR: 1.25 (95% confidence interval (CI) [1.07, 1.46]); adjusted risk difference, RD: 9 (95% CI [2, 16]) per 10,000. Similarly, those from the most deprived group were more likely to experience complications (RR: 1.26 (95% CI [1.21, 1.32]); RD: 1.14% (95% CI [0.92, 1.36])); be rehospitalised (RR: 1.16 (95% CI [1.14, 1.19]; RD: 2.78% (95% CI [2.39, 3.17])) or reoperated (RR: 1.23 (95% CI [1.13, 1.33]); RD: 0.31% (95% CI [0.19, 0.44])) and report poorer OHS (adjusted score: −2.97 (95% CI [−3.10, −2.84]) N = 200,522). There was no variation by deprivation level for THR revision rates at 5 years (RR: 1.02 (95% CI [0.94, 1.10]); RD: 0.02% (95% CI [−0.10, 0.15])). The main study limitations are the lack of complete PROMs data, and the exclusion of self-funded patients or those with private insurance for THR procedures in independent hospitals. Conclusions: Inequalities in several outcomes after THR are present in England by area-level deprivation. These findings are useful to inform shared decision-making for patients deciding whether to undergo hip replacement and to benchmark the effectiveness of policies which aim to reduce health inequalities following THR