Year 3 Research Articles

Weak Gravitational Lensing around Low Surface Brightness Galaxies in the DES Year 3 Data

We present galaxy-galaxy lensing measurements using a sample of low surface brightness galaxies (LSBGs) drawn from the Dark Energy Survey Year 3 (Y3) data as lenses. LSBGs are diffuse galaxies with a surface brightness dimmer than the ambient night sky. These dark-matter-dominated objects are intriguing due to potentially unusual formation channels that lead to their diffuse stellar component. Given the faintness of LSBGs, using standard observational techniques to characterize their total masses proves challenging. Weak gravitational lensing, which is less sensitive to the stellar component of galaxies, could be a promising avenue to estimate the masses of LSBGs. Our LSBG sample consists of 23,790 galaxies separated into red and blue color types at g−i≥0.60 and g−i<0.60, respectively. Combined with the DES Y3 shear catalog, we measure the tangential shear around these LSBGs and find signal-to-noise ratios of 6.67 for the red sample, 2.17 for the blue sample, and 5.30 for the full sample. We use the clustering redshifts method to obtain redshift distributions for the red and blue LSBG samples. Assuming all red LSBGs are satellites, we fit a simple model to the measurements and estimate the host halo mass of these LSBGs to be . We place a 95% upper bound on the subhalo mass at . By contrast, we assume the blue LSBGs are centrals, and place a 95% upper bound on the halo mass at log(Mhost/M⊙)<11.84. We find that the stellar-to-halo mass ratio of the LSBG samples is consistent with that of the general galaxy population. This work illustrates the viability of using weak gravitational lensing to constrain the halo masses of LSBGs.

Dark Energy Survey Deep Field photometric redshift performance and training incompleteness assessment

Context. The determination of accurate photometric redshifts (photo-zs) in large imaging galaxy surveys is key for cosmological studies. One of the most common approaches is machine learning techniques. These methods require a spectroscopic or reference sample to train the algorithms. Attention has to be paid to the quality and properties of these samples since they are key factors in the estimation of reliable photo-zs. Aims. The goal of this work is to calculate the photo-zs for the Year 3 (Y3) Dark Energy Survey (DES) Deep Fields catalogue using the Directional Neighborhood Fitting (DNF) machine learning algorithm. Moreover, we want to develop techniques to assess the incompleteness of the training sample and metrics to study how incompleteness affects the quality of photometric redshifts. Finally, we are interested in comparing the performance obtained by DNF on the Y3 DES Deep Fields catalogue with that of the EAzY template fitting approach. Methods. We emulated – at a brighter magnitude – the training incompleteness with a spectroscopic sample whose redshifts are known to have a measurable view of the problem. We used a principal component analysis to graphically assess the incompleteness and relate it with the performance parameters provided by DNF. Finally, we applied the results on the incompleteness to the photo-z computation on the Y3 DES Deep Fields with DNF and estimated its performance. Results. The photo-zs of the galaxies in the DES deep fields were computed with the DNF algorithm and added to the Y3 DES Deep Fields catalogue. We have developed some techniques to evaluate the performance in the absence of “true” redshift and to assess the completeness. We have studied the tradeoff in the training sample between the highest spectroscopic redshift quality versus completeness. We found some advantages in relaxing the highest-quality spectroscopic redshift requirements at fainter magnitudes in favour of completeness. The results achieved by DNF on the Y3 Deep Fields are competitive with the ones provided by EAzY, showing notable stability at high redshifts. It should be noted that the good results obtained by DNF in the estimation of photo-zs in deep field catalogues make DNF suitable for the future Legacy Survey of Space and Time (LSST) and Euclid data, which will have similar depths to the Y3 DES Deep Fields.

Abstract PO2-04-01: Predictors of exceptional response to first line HER2-targeted therapy for metastatic breast cancer

Abstract Background HER2-targeted therapies have transformed the trajectory of HER2-positive (HER2+) metastatic breast cancer (MBC), with a subgroup of responders remaining on first line (1L) therapy for many years (yrs). Despite these promising outcomes, the paradigm remains palliative, with some patients (pts) receiving therapy indefinitely. Opportunities to interrupt therapy are controversial and anecdotal in the setting of a limited understanding of long-term responders and lack of predictive biomarkers. Methods We identified prevalent pts with HER2+ MBC seen and consented at Dana-Farber Cancer Institute between 2010 and 2023, regardless of the original date of MBC diagnosis. Exceptional responders (ExRes) were pts without evidence of progressive disease (PD) 3 yrs from initiation of 1L therapy for MBC. Conventional responders (ConRes) were pts who experienced PD within 3 yrs of 1L treatment initiation. We compared clinicopathological characteristics and treatment patterns between ExRes and ConRes using Chi-square or Wilcoxon test. We analyzed median time to treatment switch due to PD (TTS-PD) – i.e., time from metastatic diagnosis to 1L treatment end due to PD - and overall survival, via the Kaplan-Meier method and with a landmark analysis at year 3 (Y3). Our primary aim was to identify predictors of exceptional response to 1L anti-HER2 therapy. Results Of 635 pts with HER2+ MBC, we identified 147 ExRes and 370 ConRes and excluded 118 pts due to follow up ≤ 3 yrs and no PD events. Median follow up was 7.1 yrs (IQR 5.5-11.0) for ExRes and 7.1 yrs (IQR 4.0-11.4) for ConRes. Median age at MBC diagnosis was 50.7 yrs (range 21.9-91.9) for ExRes and 49.8 yrs (26.9-82.3) for ConRes. ExRes presented more often with de novo MBC than ConRes (52.1 vs 30.6%, p< 0.0001). On metastatic samples, more ExRes than ConRes had HER2 3+ tumors by immunohistochemistry (IHC) (93.7 vs 81.0%, p=0.002), whereas the proportion of ER-positive disease was similar between the two groups (45.6 vs 53.4%, p=0.1). Most pts received (neo)adjuvant anti-HER2 agents in both groups (62.5 vs 72.7%, p=0.1). More ExRes than ConRes (55.8 vs 42.7% p=0.007) received 1L chemotherapy (CT) plus trastuzumab (H)/pertuzumab (P). Alternative 1L treatments were CT plus H (26.5 vs 25.7%), H +/- P +/- endocrine therapy (8.2 vs 10.5%), T-DM1 (2 vs 9.2%), tyrosine kinase inhibitors-based regimens (7.5 vs 10.8%). For pts with recurrent MBC, disease-free interval was longer for ExRes than ConRes (median 4.7 vs 3.4 yrs, p=0.01). Visceral involvement at MBC relapse was similar for ExRes and ConRes (78.2 vs 77.8%, p=0.9). Brain metastases at any timepoint were less frequent among ExRes than ConRes (42.9 vs 55.1%, p=0.01). Among ExRes, 70 (47.6%) pts experienced PD after Y3, with a median TTS-PD of 4.6 (4.1-5.1) yrs. In a landmark analysis at Y3, the 2-year TTS-PD was 68.5% (95% CI: 59.8%-75.7%) (5 yrs from treatment start), and 4-year overall survival was 86.5% (95% CI: 78.1%-91.9%) (7 yrs from treatment start). ConRes received a median of 5 (1-19) treatment regimens for MBC, with a median 1L TTS-PD of 12 (10.8-13) mo. A total of 89 (60.5%) ExRes and 214 (57.8%) ConRes underwent tumor sequencing. Data comparing genomic features between ExRes and ConRes will be presented. Conclusions In this prospective cohort, 28% of pts with HER2+ MBC had exceptional response to 1L anti-HER2 therapy. Consistent with prior data, ExRes present more frequently with de novo disease and HER2 IHC 3+ tumors. In our cohort, ExRes had a median follow-up of 7.1 years and 52.4% never experienced PD. Although a significant proportion of pts with HER2+ MBC derive long-term benefit from anti-HER2 therapy, the treatment paradigm remains palliative, and it is unknown whether biomarkers may reliably predict exceptional response and guide future treatment. Ongoing work will explore whether genomic features vary between ExRes and ConRes. Citation Format: Stefania Morganti, Tianyu Li, Katheryn Santos, Melissa Hughes, Nolan Priedigkeit, Yvonne Li, Marla Lipsyc-Sharf, Gregory Kirkner, Janet Files, Julie Kasparian, Elizabeth Grant, Gunjan Gupta, Giuseppe Curigliano, Sara Tolaney, Andrew Cherniack, Nabihah Tayob, Nancy Lin, Heather Parsons. Predictors of exceptional response to first line HER2-targeted therapy for metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-04-01.

Detection of the significant impact of source clustering on higher order statistics with DES Year 3 weak gravitational lensing data

ABSTRACT We measure the impact of source galaxy clustering on higher order summary statistics of weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not trace the underlying density field, we show that this effect can exceed measurement uncertainties for common higher order statistics for certain analysis choices. We evaluate the impact on different weak lensing observables, finding that third moments and wavelet phase harmonics are more affected than peak count statistics. Using Dark Energy Survey (DES) Year 3 (Y3) data, we construct null tests for the source-clustering-free case, finding a p-value of p = 4 × 10−3 (2.6σ) using third-order map moments and p = 3 × 10−11 (6.5σ) using wavelet phase harmonics. The impact of source clustering on cosmological inference can be either included in the model or minimized through ad hoc procedures (e.g. scale cuts). We verify that the procedures adopted in existing DES Y3 cosmological analyses were sufficient to render this effect negligible. Failing to account for source clustering can significantly impact cosmological inference from higher order gravitational lensing statistics, e.g. higher order N-point functions, wavelet-moment observables, and deep learning or field-level summary statistics of weak lensing maps.

Comprehensive transcriptional analysis of pig facial skin development.

Skin development is a complex process that is influenced by many factors. Pig skin is used as an ideal material for xenografts because it is more anatomically and physiologically similar to human skin. It has been shown that the skin development of different pig breeds is different, and some Chinese pig breeds have the characteristics of skin thickness and facial skin folds, but the specific regulatory mechanism of this skin development is not yet clear. In this study, the facial skin of Chenghua sows in the four developmental stages of postnatal Day 3 (D3) , Day 90 (D90) , Day 180 (D180), and Year 3 (Y3) were used as experimental materials, and RNA sequencing (RNA-seq) analysis was used to explore the changes in RNA expression in skin development at the four developmental stages, determine the differentially expressed messenger RNAs (mRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), and perform functional analysis of related genes by Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. A pairwise comparison of the four developmental stages identified several differentially expressed genes (DEGs) and found that the number of differentially expressed RNAs (DE RNAs) increased with increasing developmental time intervals. Elastin (ELN) is an important component of the skin. Its content affects the relaxation of the epidermis and dermal connection, and its expression is continuously downregulated during the four developmental stages. The functions of DEGs at different developmental stages were examined by performing GO and KEGG analyses, and the GO terms and enrichment pathways of mRNAs, lncRNAs, miRNAs, and circRNAs highly overlapped, among which the PPAR signaling pathway, a classical pathway for skin development, was enriched by DEGs of D3 vs. D180, D90 vs. D180 and D180 vs. Y3. In addition, we constructed lncRNA-miRNA-mRNA and circRNA-miRNA interaction networks and found genes that may be associated with skin development, but their interactions need further study. We identified a number of genes associated with skin development, performed functional analyses on some important DEGs and constructed interaction networks that facilitate further studies of skin development.

A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis

ABSTRACT Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this work, we demonstrate a general framework for detecting and modelling the impact of PSF systematics on the cosmic shear 2PCF and mitigating its impact on cosmological analysis. Our framework can detect PSF leakage and modelling error from all spin-2 quantities contributed by the PSF second and higher moments, rather than just the second moments, using the cross-correlations between galaxy shapes and PSF moments. We interpret null tests using the HSC Year 3 (Y3) catalogs with this formalism and find that leakage from the spin-2 combination of PSF fourth moments is the leading contributor to additive shear systematics, with total contamination that is an order-of-magnitude higher than that contributed by PSF second moments alone. We conducted a mock cosmic shear analysis for HSC Y3 and find that, if uncorrected, PSF systematics can bias the cosmological parameters Ωm and S8 by ∼0.3σ. The traditional second moment-based model can only correct for a 0.1σ bias, leaving the contamination largely uncorrected. We conclude it is necessary to model both PSF second and fourth moment contaminations for HSC Y3 cosmic shear analysis. We also reanalyse the HSC Y1 cosmic shear analysis with our updated systematics model and identify a 0.07σ bias on Ωm when using the more restricted second moment model from the original analysis. We demonstrate how to self-consistently use the method in both real space and Fourier space, assess shear systematics in tomographic bins, and test for PSF model overfitting.

The Effect of Clonal Hematopoiesis of Indeterminate Potential (CHIP) and Aspirin on Clinical Outcomes in the Healthy Elderly: A Sub-Study of the Aspirin in Reducing Events in the Elderly (ASPREE) Randomized Controlled Trial

Background Clonal hematopoiesis of indeterminate potential (CHIP) increases with age and is a risk factor for blood cancer, cardiovascular disease (CVD) and other diseases. Recent experimental evidence suggests a causal link between CHIP and CVD, however it is not known whether individuals with CHIP are more likely to benefit from preventive interventions for CVD, such as low-dose aspirin. ASPREE was a double-blind, randomized, placebo-controlled trial comparing 100mg aspirin with placebo on disability-free survival (DFS, composed of death, dementia and physical disability) in initially healthy participants aged ≥70y (≥65y for US minorities of Black and Hispanic background). We measured CHIP in serial blood samples of 11,298 ASPREE participants at baseline and/or year 3 (Y3), and assessed incidence of CHIP and its association with various clinical outcomes. We also examined whether randomization to aspirin had a differential effect on clinical outcomes according to the presence of CHIP at study entry. Methods CHIP was measured in 19 CHIP-associated genes using a custom targeted amplicon-based NGS assay, designed to have a sensitivity of 0.5-2% variant allele fraction (VAF). CHIP was defined as a VAF ≥ 2%. We evaluated the association of CHIP at baseline and Y3, defined as a categorical variable (VAF< 2%, VAF 2-10%, VAF >10%), with clinical outcomes, including DFS, all-cause mortality, cancer and major adverse cardiovascular events (MACE, composed of fatal coronary heart disease, non-fatal myocardial infarction and ischemic stroke) using Y3-landmark Cox proportional hazards models. Risk factors for incident CHIP at Y3 were identified using multivariable logistic regression. Treatment heterogeneity of aspirin was assessed in CHIP subgroups overall and by the most common genes. Results CHIP was present in 3,345/9,926 (34%) participants at baseline and in 3,685/9,812 (39%) at Y3. Of the 5,612 participants without CHIP at baseline who had a Y3 sample, 1,195 (25%) developed CHIP by Y3 (incidence 7% per year). Risk factors for incident CHIP included cancer history (odds ratio [OR] (95% CI) 1.20 [1.02-1.41] P=0.031), and family history of blood cancer (OR 1.50 [1.16-1.93] P=0.002). With regards to clinical outcomes, the presence of CHIP at >10% VAF at baseline (but not VAF 2-10%) was associated with increased all-cause mortality (adjusted [aHR] [95% CI] 1.53 [1.23-1.90] P<0.001). This increased risk appeared to be driven by increased cancer-related mortality (baseline aHR 1.62, [1.19-2.22] p=0.002) more than cardiovascular-related mortality (baseline aHR 1.34 [0.84-2.12] p=0.21). CHIP at >10% at baseline and Y3 was also associated with increased risk of blood cancer (HR 2.48 [1.59-3.88] and 3.24 [1.98-5.30], both P<0.001) and other cancers at Y3 (HR 1.31 [1.02-1.68] P=0.033). After adjustment for potential confounders, this association remained significant for blood cancers (aHR 2.29 [1.44-3.62] p<0.001) but not non-blood cancers (aHR 1.21 [0.98 -1.48] P=0.07). There was no evidence of an association between CHIP at 2-10% and >10% with MACE (aHR 0.91 [0.74-1.11] P=0.34 and aHR 0.73 [0.50-1.07] P=0.11, respectively). There was no evidence of a differential effect of aspirin on DFS according to presence of CHIP at study entry (CHIP HR 0.91 [0.77-1.07], no-CHIP HR 0.88 [0.70-1.10], test for heterogeneity P=0.83) or on MACE (CHIP HR 1.23 [0.85-1.80], no-CHIP HR 0.80 [0.62-1.03] heterogeneity P=0.06) - Figure 1. There was no subgroup difference for the effect of aspirin on incident cancer or cancer-related mortality. Participants with detectable JAK2V617F (VAF > 0.5%, n=123) had worse outcomes if randomized to aspirin, including the primary outcome of DFS (Fig 1). There was no differential effect of aspirin in the JAK2V617F subgroup for MACE (Fig 1). Conclusions This is the largest primary CVD prevention trial to evaluate the intervention effect according to presence of CHIP in healthy elderly. We found CHIP at >10% VAF was associated with increased all-cause mortality, which appeared to be driven largely by increased cancer-related mortality. There was no evidence that participants with CHIP were more likely to benefit from aspirin, including for MACE. Furthermore, aspirin appeared to reduce DFS for individuals with JAK2V617F mutation, although sub-group numbers were small. Our results suggest aspirin should not be used for primary prevention in older individuals with CHIP, including JAK2V617F. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

SEVERE COPD EXACERBATIONS IN THE UNITED STATES: EVALUATION OF RISK AMONG MEDICARE PATIENTS WITH MODERATE OR NO BASELINE EXACERBATIONS

SEVERE COPD EXACERBATIONS IN THE UNITED STATES: EVALUATION OF RISK AMONG MEDICARE PATIENTS WITH MODERATE OR NO BASELINE EXACERBATIONS

FP.34 Clinical outcome study of dysferlinopathy: correlation between MRI fat fraction in lower limbs and clinical outcome assessments over a 3-year period

The Jain Foundation COS of dysferlinopathy is an international study in genetically confirmed dysferlinopathy patients, with the aim to identify relevant outcome measures to facilitate trial readiness. Due to its wide range of clinical phenotypes and rates of disease progression, an objective marker to quantify disease progression would be ideal. We assessed the application of quantitative magnetic resonance imaging (MRI) as a prognostic tool for these patients. Our aim is to establish whether there is a correlation between fat fraction (FF) in thigh and/or lower leg muscles and clinical outcome assessments (COA) when comparing baseline (BL) values and changes from BL to year 1 (Y1) and to year 3 (Y3). We selected 84 patients from COS1 who had a Dixon MRI of the lower limbs (LL) and at least one of the following COA: time to rise from floor (RFF), time to climb / descend 4 steps (4SC/4SD), time up and go (TUG), time to walk 10m (10MWT), 6 min walk test (6MWT) and North Star Assessment for limb girdle type muscular dystrophy (NSAD) score. Spearman correlation (rs) was performed using SPSS statistics, p value 0.05. We found a significant correlation at BL between LL FF values and all COA, with the highest rs between thigh FF and NSAD (-.675) and 6MWT (-.665). We didn't find any correlations between changes in FF between BL and Y1 and changes in COA during that same period, but we did observe a significant correlation with changes in TUG (.445) and 4SC (.41) between BL and Y3. We observed a significant correlation between changes in thigh FF between BL and Y3 and changes in TUG (.706), RFF (.607), 4SC (.545) and NSAD[HR1] (-.374). No correlations were found when analysing changes in lower legs FF and COA. Our results show that changes in FF of the thigh muscles over one year could predict functional changes at a later stage, in a three-year period, suggesting that MRI could be used to identify dysferlinopathy patients at risk of more severe disease progression in routine clinical care.

Dark Energy Survey Year 3 results: Imprints of cosmic voids and superclusters in the Planck CMB lensing map

ABSTRACT The CMB lensing signal from cosmic voids and superclusters probes the growth of structure in the low-redshift cosmic web. In this analysis, we cross-correlated the Planck CMB lensing map with voids detected in the Dark Energy Survey Year 3 (Y3) data set (∼5000 deg2), expanding on previous measurements that used Y1 catalogues (∼1300 deg2). Given the increased statistical power compared to Y1 data, we report a 6.6σ detection of negative CMB convergence (κ) imprints using approximately 3600 voids detected from a redMaGiC luminous red galaxy sample. However, the measured signal is lower than expected from the MICE N-body simulation that is based on the ΛCDM model (parameters Ωm = 0.25, σ8 = 0.8), and the discrepancy is associated mostly with the void centre region. Considering the full void lensing profile, we fit an amplitude $A_{\kappa }=\kappa _{{\rm DES}}/\kappa _{{\rm MICE}}$ to a simulation-based template with fixed shape and found a moderate 2σ deviation in the signal with Aκ ≈ 0.79 ± 0.12. We also examined the WebSky simulation that is based on a Planck 2018 ΛCDM cosmology, but the results were even less consistent given the slightly higher matter density fluctuations than in MICE. We then identified superclusters in the DES and the MICE catalogues, and detected their imprints at the 8.4σ level; again with a lower-than-expected Aκ = 0.84 ± 0.10 amplitude. The combination of voids and superclusters yields a 10.3σ detection with an Aκ = 0.82 ± 0.08 constraint on the CMB lensing amplitude, thus the overall signal is 2.3σ weaker than expected from MICE.

Dark Energy Survey Year 3 Results: Measuring the Survey Transfer Function with Balrog

Abstract We describe an updated calibration and diagnostic framework, Balrog, used to directly sample the selection and photometric biases of the Dark Energy Survey (DES) Year 3 (Y3) data set. We systematically inject onto the single-epoch images of a random 20% subset of the DES footprint an ensemble of nearly 30 million realistic galaxy models derived from DES Deep Field observations. These augmented images are analyzed in parallel with the original data to automatically inherit measurement systematics that are often too difficult to capture with generative models. The resulting object catalog is a Monte Carlo sampling of the DES transfer function and is used as a powerful diagnostic and calibration tool for a variety of DES Y3 science, particularly for the calibration of the photometric redshifts of distant “source” galaxies and magnification biases of nearer “lens” galaxies. The recovered Balrog injections are shown to closely match the photometric property distributions of the Y3 GOLD catalog, particularly in color, and capture the number density fluctuations from observing conditions of the real data within 1% for a typical galaxy sample. We find that Y3 colors are extremely well calibrated, typically within ∼1–8 mmag, but for a small subset of objects, we detect significant magnitude biases correlated with large overestimates of the injected object size due to proximity effects and blending. We discuss approaches to extend the current methodology to capture more aspects of the transfer function and reach full coverage of the survey footprint for future analyses.

Integrating evidence-based medicine skills into a medical school curriculum: a quantitative outcomes assessment

ObjectivesThis research project aims to determine the potential differential impact of two curricular approaches to teaching evidence-based medicine (EBM) on student performance on an EBM assignment administered during the first...

Impact of Victoria's first dedicated endocrine hypertension service on the pattern of primary aldosteronism diagnoses.

Primary aldosteronism (PA) accounts for 3.2-12.7% of hypertension in primary care but is often diagnosed late, if at all. A delayed or missed diagnosis leads to poor blood pressure control and greater cardiovascular risk. To analyse the impact of Victoria's first dedicated endocrine hypertension service (EHS) on the pattern of PA diagnosis. Socio-demographic and clinical data from all patients who attended the EHS since July 2016 (n = 267) was collected prospectively. Patients were divided into Year 1 (Y1), Year 2 (Y2) and Year 3 (Y3), based on their first visit. The proportion of primary care referrals increased (20% in Y1, 47% in Y2, 52% in Y3) with more referrals being made for treatment-naive hypertension (3% in Y1, 14% in Y2, 19% in Y3). Among PA patients, the median duration of hypertension prior to their first visit decreased (11 years in Y1, 10 years in Y2, 7 years in Y3), and the prevalence of end-organ damage decreased (44% in Y1, 42% in Y2, 33% in Y3). Targeted management of PA improved clinical and biochemical outcomes. The average blood pressure reduction following targeted management increased from 16/12 mmHg in Y1 to 23/12 mmHg in Y3. The EHS, with its strong component of general practitioner engagement, led to increased primary care referrals and PA detection earlier in the course of hypertension. Referred patients were on fewer antihypertensives and had less end-organ damage which simplified the diagnostic process, allowing targeted treatment to be commenced earlier and patient outcomes optimised.

Prevalence and Correlation Analysis of Soil-Transmitted Helminths Infections and Treatment Coverage for Preschool and School Aged Children in Kenya: Secondary Analysis of the National School Based Deworming Program Data.

Background: Soil-transmitted helminths (STH) are among the most common parasitic infections globally, disproportionately affecting children. Treatment of STH in Kenya is often targeted at preschool (PSAC) and school aged (SAC) children delivered through annual mass drug administration (MDA) in primary schools. Understanding group-specific prevalence and dynamics between treatment and coverage is critical for continued treatment success. This study aims to provide detailed information on group-specific infection prevalence and relative reductions (RR), and their relationships with treatment coverage over time. Additionally, it aims to quantify the correlation between the observed school level infection prevalence and treatment coverage.Methods: Secondary analysis of existing data collected between 2012 and 2018 by the monitoring and evaluation (M&E) program of the National School-Based Deworming (NSBD) program was used. The M&E program conducted surveys utilizing cross-sectional study design, at four survey time points, in a nationally-representative sample of schoolchildren across counties in Kenya. In each participating school, the program randomly sampled 108 children per school, of both groups. Infection prevalence was estimated using binomial regression, RR in prevalence using multivariable mixed effects model, statistical correlations using structural equation modeling, and change-point-analysis using the binary segmentation algorithm.Results: Overall, STH prevalence for PSAC was 33.7, 20.2, 19.0, and 17.9% during Year 1 (Y1), Year 3 (Y3), Year 5 (Y5), and Year 6 (Y6) surveys, respectively with an overall RR of 46.9% (p = 0.001) from Y1 to Y6. Similarly, overall STH prevalence for SAC was 33.6, 18.4, 14.7, and 12.5% during Y1, Y3, Y5, and Y6 surveys, respectively with an overall RR of 62.6% (p < 0.001). An overall (all time points) significant but very weak negative correlation was found between treatment coverage and undifferentiated STH prevalence (r = −0.144, p = 0.002) among PSAC but not in SAC. Further, we observed inter-county heterogeneity variation in infection prevalence, RR, as well as correlations.Conclusion: The analysis showed that after six rounds of MDA, prevalence of STH has significantly declined among both groups of children, however not to a point where it is not a public health problem (below 1%). The analysis, additionally established an overall significant but weak negative correlation between treatment coverage and prevalence, indicating that the current treatment coverage might not be sufficient to drive the overall STH prevalence to below 1%. These findings will allow STH control programs in Kenya to make decisions that will accelerate the attainment of STH elimination as a public health problem.

The role of training in student examiner rating performance in astudent-led mock OSCE.

IntroductionPeer assessments are increasingly prevalent in medical education, including student-led mock Objective Structured Clinical Examinations (OSCE). While there is some evidence to suggest that examiner training may improve OSCE assessments, few students undergo training before becoming examiners. We sought to evaluate an examiner training programme in the setting of a student-led mock OSCE.MethodsA year‑2 mock OSCE comprised of history taking (Hx) and physical examination (PE) stations was conducted involving 35 year‑3 (Y3) student examiners and 21 year‑5 (Y5) student examiners who acted as reference examiners. Twelve Y3 student-examiners attended an OSCE examiner training programme conducted by senior faculty. During the OSCE, Y3 and Y5 student examiners were randomly paired to grade the same candidates and scores were compared. Scores for checklist rating (CR) and global rating (GR) domains were assigned for both Hx and PE stations.ResultsThere was moderate to excellent correlation between Y3 and Y5 student examiners for both Hx (ICC 0.71–0.96) and PE stations (ICC 0.71–0.88) across all domains. For both Hx and PE stations, GR domain had poorer correlation than CR domains. Examiner training resulted in better correlations for PE but not Hx stations. Effect sizes were lower than the minimum detectible effect (MDE) sizes for all comparisons made.DiscussionY3 student examiners are effective substitutes for Y5 student examiners in a Y2 mock OSCE. Our findings suggest that examiner training may further improve marking behaviour especially for PE stations. Further studies with larger sample sizes are required to further evaluate the effects of dedicated examiner training.

SAT-558 A Dedicated Endocrine Hypertension Service Increases the Timely Diagnosis of Primary Aldosteronism

Background: Primary aldosteronism (PA) accounts for 3.2-12.7% of hypertension in primary care but is often diagnosed late, if at all. A delayed or missed diagnosis leads to poor blood pressure control and greater cardiovascular risk that could be averted with targeted treatment. An Endocrine Hypertension Service (EHS), encompassing an education program, streamlined diagnostic tests and dedicated PA clinic, was developed to address this issue. Aims: To analyse the impact of Victoria’s first dedicated EHS on the pattern of PA diagnoses. Methods: Socio-demographic and clinical data from all patients who attended the EHS since July 2016 (N=267) was collected prospectively. Patients were divided into Year 1 (Y1), Year 2 (Y2), and Year 3 (Y3), based on their first visit. Results: The proportion of referrals from primary care increased (20% in Y1 to 52% in Y3) with more referrals being made for treatment-naive hypertension (3% in Y1 to 19% in Y3). Patients with a hypertension diagnosis of 5 years or less at the time of referral to EHS increased from 34% in Y1 to 45% in Y3 whilst the percentage of patients with a hypertension diagnosis of more than 10 years decreased from 50% in Y1 to 35% in Y3. Consistent with an earlier presentation, the proportion of patients with end-organ damage at the time of referral decreased from 44% in Y1 to 29% in Y3. Almost a third of the PA patients had unilateral disease; all of those who underwent adrenalectomy had biochemical cure. Patients with bilateral PA were treated with spironolactone. Their systolic/diastolic blood pressure decreased by 15/12 mmHg in Y1, 17/13 mmHg in Y2 and 23/11 mmHg in Y3; while the mean number of antihypertensive medications decreased from 2.9 to 1.8 in Y1, 2.7 to 2.0 in Y2 and 2.2 to 1.6 in Y3 Conclusion: The EHS has facilitated an increase in referrals for PA screening from primary care, resulting in the earlier diagnosis of PA, when less complications are present, and optimised patient outcomes. A broader uptake of such a clinical service, integrated with education outreach, will bridge the gap between the reported high prevalence of PA and the actual low diagnostic rates.

Insights into student assessment outcomes in rural clinical campuses

BackgroundThere is an ongoing debate about the impact of studying medicine in rural vs. metropolitan campuses on student assessment outcomes. The UNSW Medicine Rural Clinical School has five main campuses; Albury-Wodonga, Coffs Harbour, Griffith, Port Macquarie and Wagga Wagga. Historical data of student assessment outcomes at these campuses raised concerns regarding potential biases in assessment undertaken, as well as the availability and quality of learning resources. The current study aims to identify the extent to which the location of examination (rural versus metropolitan) has an impact on student marks in OSCEs.MethodsAssessment data was employed for this study from 275 medical students who sat their final examinations in Years 3 and 6 of the undergraduate Medicine program at UNSW in 2018. The data consists of matched student assessment results from the Year 3 (Y3) MCQ examination and OSCE, and from the Year 6 (Y6) MCQ, OSCE and management viva examinations. The analysis used Univariate Analysis of Variance and linear regression models to identify the impact of site of learning and site of examination on assessment outcomes.ResultsThe results demonstrate that neither site of learning nor site of examination had any significant impact on OSCE or Management Viva assessment outcomes while potential confounders are controlled.ConclusionIt is suggested that some of the supposed disadvantages inherent at rural campuses are effectively mitigated by perceived advantages; more intensive interaction with patients, the general and medical communities at those sites, as well as effective e-learning resources and moderation of assessment grades.

Changes in physical activity, sedentary time, and risk of falling: The Women's Health Initiative Observational Study

Falling significantly affects quality of life, morbidity, and mortality among older adults. We sought to evaluate the prospective association between sedentary time, physical activity, and falling among post-menopausal women aged 50–79years recruited to the Women's Health Initiative Observational Study between 1993 and 1998 from 40 clinical centers across the United States. Baseline (B) and change in each of the following were evaluated at year 3 (Y3) and year 6 (Y6; baseline n=93,676; Y3 n=76,598; Y6 n=75,428): recreational physical activity (MET-h/wk), sitting, sleeping (min/day), and lean body mass by dual energy X-ray absorptiometry (subset N=6475). Falls per year (0, 1, 2, ≥3) were assessed annually by self-report questionnaire and then dichotomized as ≤1 and ≥2falls/year. Logistic regression models were adjusted for demographics, body mass index, fall history, tobacco and alcohol use, medical conditions, and medications. Higher baseline activity was associated with greater risk of falling at Y6 (18%; p for trend <0.0001). Increasing sedentary time minimally decreased falling (1% Y3; 2% Y6; p<0.05). Increasing activity up to ≥9MET-h/wk. (OR: 1.12, 95% CI: 1.03–1.22) or maintaining ≥9MET-h/wk. (OR: 1.20, 95% CI: 1.13–1.29) increased falling at Y3 and Y6 (p for trend <0.001). Adding lean body mass to the models attenuated these relationships. Physically active lifestyles increased falling among post-menopausal women. Additional fall prevention strategies, such as balance and resistance training, should be evaluated to assist post-menopausal women in reaching or maintaining levels of aerobic activity known to prevent and manage several chronic diseases.

Online dissection audio-visual resources for human anatomy: Undergraduate medical students' usage and learning outcomes.

In an attempt to improve undergraduate medical student preparation for and learning from dissection sessions, dissection audio-visual resources (DAVR) were developed. Data from e-learning management systems indicated DAVR were accessed by 28% ± 10 (mean ± SD for nine DAVR across three years) of students prior to the corresponding dissection sessions, representing at most 58% ± 20 of assigned dissectors. Approximately 50% of students accessed all available DAVR by the end of semester, while 10% accessed none. Ninety percent of survey respondents (response rate 58%) generally agreed that DAVR improved their preparation for and learning from dissection when used. Of several learning resources, only DAVR usage had a significant positive correlation (P = 0.002) with feeling prepared for dissection. Results on cadaveric anatomy practical examination questions in year 2 (Y2) and year 3 (Y3) cohorts were 3.9% (P < 0.001, effect size d = -0.32) and 0.3% lower, respectively, with DAVR available compared to previous years. However, there were positive correlations between students' cadaveric anatomy question scores with the number and total time of DAVR viewed (Y2, r = 0.171, 0.090, P = 0.002, n.s., respectively; and Y3, r = 0.257, 0.253, both P < 0.001). Students accessing all DAVR scored 7.2% and 11.8% higher than those accessing none (Y2, P = 0.015, d = 0.48; and Y3, P = 0.005, d = 0.77, respectively). Further development and promotion of DAVR are needed to improve engagement and learning outcomes of more students. Anat Sci Educ 9: 545-554. © 2016 American Association of Anatomists.

Population dynamics and production effects of sheep lice (Bovicola ovis Schrank) in extensively grazed flocks

An experiment was conducted to characterise population dynamics of lice and associated production loss in extensively grazed flocks infested at different times after shearing. Merino wethers were allocated to six groups of 31 sheep. In the first year (Y1), one sheep in each of two groups was infested with 2500 lice at 6 weeks after shearing (September), sheep in two groups were infested at 4 months (December) and two groups remained uninfested. In year 2 (Y2), infestations carried over from Y1, but a lousy sheep was added to each 6-week infestation mob. In year 3 (Y3), the infested mobs were treated and remained lice free, while lousy donor sheep were added to the two previously uninfested mobs. In Y1, lice appeared to die out in one 6-week-infestation group and were found on only two sheep before next shearing in the other. Lice persisted and spread in the two 4-month-infestation flocks, reaching mean counts (±s.e.) of 0.5 (±0.2) and 0.2 (±0.1) per part before shearing. In Y2 and Y3, lice persisted and increased in all infested flocks, reaching mean counts of 2.3 (±0.6), 8.5 (±1.5), 3.6 (±0.6) and 2.8 (±0.7) per part in Y2 and 1.0 (±0.2) and 1.2 (±0.4) per part in Y3. The count of 8.5 was in the flock with both a carry-over infestation and an infestor sheep. Exponential and logistic models were fitted to describe lice increase; differences in fleece derangement reflected louse numbers. Clean fleece weight was higher in flocks without lice in all years (0.12 kg/head in Y1; 0.22 kg/head in Y2 and Y3; P &lt; 0.05). Classer-assigned colour scores (although not measured colour), cott score and line into which the wool was classed also differed significantly (P &lt; 0.05) between infested and non-infested flocks and there was an indication that staple length was reduced in more heavily infested flocks. In spring-shorn flocks in environments with high solar radiation and no lice present at shearing, even if lice subsequently enter the mob, it appears unlikely that they will increase to levels where serious economic loss will be experienced before next shearing. The study also indicated that lice could persist in flocks at levels unlikely to be detected by most commercial wool producers for extended periods, possibly through one season, which may help to explain reports of new infestations with no apparent source.