145 research outputs found

    The resultant on compact Riemann surfaces

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    We introduce a notion of resultant of two meromorphic functions on a compact Riemann surface and demonstrate its usefulness in several respects. For example, we exhibit several integral formulas for the resultant, relate it to potential theory and give explicit formulas for the algebraic dependence between two meromorphic functions on a compact Riemann surface. As a particular application, the exponential transform of a quadrature domain in the complex plane is expressed in terms of the resultant of two meromorphic functions on the Schottky double of the domain.Comment: 44 page

    Endocrine Therapy Nonadherence and Discontinuation in Black and White Women

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    Background: Differential use of endocrine therapy (ET) by race may contribute to breast cancer outcome disparities, but racial differences in ET behaviors are poorly understood. Methods: Women aged 20-74 years with a first primary, stage I-III, hormone receptor-positive (HR+) breast cancer were included. At 2 years postdiagnosis, we assessed nonadherence, defined as not taking ET every day or missing more than two pills in the past 14 days, discontinuation, and a composite measure of underuse, defined as either missing pills or discontinuing completely. Using logistic regression, we evaluated the relationship between race and nonadherence, discontinuation, and overall underuse in unadjusted, clinically adjusted, and socioeconomically adjusted models. Results: A total of 1280 women were included; 43.2% self-identified as black. Compared to white women, black women more often reported nonadherence (13.7% vs 5.2%) but not discontinuation (10.0% vs 10.7%). Black women also more often reported the following: hot flashes, night sweats, breast sensitivity, and joint pain; believing that their recurrence risk would not change if they stopped ET; forgetting to take ET; and cost-related barriers. In multivariable analysis, black race remained statistically significantly associated with nonadherence after adjusting for clinical characteristics (adjusted odds ratio = 2.72, 95% confidence interval = 1.75 to 4.24) and after adding socioeconomic to clinical characteristics (adjusted odds ratio = 2.44, 95% confidence interval = 1.50 to 3.97) but was not independently associated with discontinuation after adjustment. Low recurrence risk perception and lack of a shared decision making were strongly predictive of ET underuse across races. Conclusions: Our results highlight important racial differences in ET-Adherence behaviors, perceptions of benefits/harms, and shared decision making that may be targeted with culturally tailored interventions

    Innovations in suicide prevention research (INSPIRE): a protocol for a population-based case–control study

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    Background Suicide deaths have been increasing for the past 20 years in the USA resulting in 45 979 deaths in 2020, a 29% increase since 1999. Lack of data linkage between entities with potential to implement large suicide prevention initiatives (health insurers, health institutions and corrections) is a barrier to developing an integrated framework for suicide prevention. Objectives Data linkage between death records and several large administrative datasets to (1) estimate associations between risk factors and suicide outcomes, (2) develop predictive algorithms and (3) establish long-term data linkage workflow to ensure ongoing suicide surveillance. Methods We will combine six data sources from North Carolina, the 10th most populous state in the USA, from 2006 onward, including death certificate records, violent deaths reporting system, large private health insurance claims data, Medicaid claims data, University of North Carolina electronic health records and data on justice involved individuals released from incarceration. We will determine the incidence of death from suicide, suicide attempts and ideation in the four subpopulations to establish benchmarks. We will use a nested case–control design with incidence density-matched population-based controls to (1) identify short-term and long-term risk factors associated with suicide attempts and mortality and (2) develop machine learning-based predictive algorithms to identify individuals at risk of suicide deaths. Discussion We will address gaps from prior studies by establishing an in-depth linked suicide surveillance system integrating multiple large, comprehensive databases that permit establishment of benchmarks, identification of predictors, evaluation of prevention efforts and establishment of long-term surveillance workflow protocols

    The Science of Sungrazers, Sunskirters, and Other Near-Sun Comets

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    This review addresses our current understanding of comets that venture close to the Sun, and are hence exposed to much more extreme conditions than comets that are typically studied from Earth. The extreme solar heating and plasma environments that these objects encounter change many aspects of their behaviour, thus yielding valuable information on both the comets themselves that complements other data we have on primitive solar system bodies, as well as on the near-solar environment which they traverse. We propose clear definitions for these comets: We use the term near-Sun comets to encompass all objects that pass sunward of the perihelion distance of planet Mercury (0.307 AU). Sunskirters are defined as objects that pass within 33 solar radii of the Sun’s centre, equal to half of Mercury’s perihelion distance, and the commonly-used phrase sungrazers to be objects that reach perihelion within 3.45 solar radii, i.e. the fluid Roche limit. Finally, comets with orbits that intersect the solar photosphere are termed sundivers. We summarize past studies of these objects, as well as the instruments and facilities used to study them, including space-based platforms that have led to a recent revolution in the quantity and quality of relevant observations. Relevant comet populations are described, including the Kreutz, Marsden, Kracht, and Meyer groups, near-Sun asteroids, and a brief discussion of their origins. The importance of light curves and the clues they provide on cometary composition are emphasized, together with what information has been gleaned about nucleus parameters, including the sizes and masses of objects and their families, and their tensile strengths. The physical processes occurring at these objects are considered in some detail, including the disruption of nuclei, sublimation, and ionisation, and we consider the mass, momentum, and energy loss of comets in the corona and those that venture to lower altitudes. The different components of comae and tails are described, including dust, neutral and ionised gases, their chemical reactions, and their contributions to the near-Sun environment. Comet-solar wind interactions are discussed, including the use of comets as probes of solar wind and coronal conditions in their vicinities. We address the relevance of work on comets near the Sun to similar objects orbiting other stars, and conclude with a discussion of future directions for the field and the planned ground- and space-based facilities that will allow us to address those science topics

    Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration

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    Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non-statistical fluctuations, and suppression of particle production at high p_T. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted to Nuclear Physics A as a regular article; v3 has minor changes in response to referee comments. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Structured lifestyle education to support weight loss for people with schizophrenia, schizoaffective disorder and first episode psychosis: the STEPWISE RCT.

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    BACKGROUND: Obesity is twice as common in people with schizophrenia as in the general population. The National Institute for Health and Care Excellence guidance recommends that people with psychosis or schizophrenia, especially those taking antipsychotics, be offered a healthy eating and physical activity programme by their mental health care provider. There is insufficient evidence to inform how these lifestyle services should be commissioned. OBJECTIVES: To develop a lifestyle intervention for people with first episode psychosis or schizophrenia and to evaluate its clinical effectiveness, cost-effectiveness, delivery and acceptability. DESIGN: A two-arm, analyst-blind, parallel-group, randomised controlled trial, with a 1 : 1 allocation ratio, using web-based randomisation; a mixed-methods process evaluation, including qualitative case study methods and logic modelling; and a cost-utility analysis. SETTING: Ten community mental health trusts in England. PARTICIPANTS: People with first episode psychosis, schizophrenia or schizoaffective disorder. INTERVENTIONS: Intervention group: (1) four 2.5-hour group-based structured lifestyle self-management education sessions, 1 week apart; (2) multimodal fortnightly support contacts; (3) three 2.5-hour group booster sessions at 3-monthly intervals, post core sessions. Control group: usual care assessed through a longitudinal survey. All participants received standard written lifestyle information. MAIN OUTCOME MEASURES: The primary outcome was change in weight (kg) at 12 months post randomisation. The key secondary outcomes measured at 3 and 12 months included self-reported nutrition (measured with the Dietary Instrument for Nutrition Education questionnaire), objectively measured physical activity measured by accelerometry [GENEActiv (Activinsights, Kimbolton, UK)], biomedical measures, adverse events, patient-reported outcome measures and a health economic assessment. RESULTS: The trial recruited 414 participants (intervention arm: 208 participants; usual care: 206 participants) between 10 March 2015 and 31 March 2016. A total of 341 participants (81.6%) completed the trial. A total of 412 participants were analysed. After 12 months, weight change did not differ between the groups (mean difference 0.0 kg, 95% confidence interval -1.59 to 1.67 kg; p = 0.964); physical activity, dietary intake and biochemical measures were unchanged. Glycated haemoglobin, fasting glucose and lipid profile were unchanged by the intervention. Quality of life, psychiatric symptoms and illness perception did not change during the trial. There were three deaths, but none was related to the intervention. Most adverse events were expected and related to the psychiatric illness. The process evaluation showed that the intervention was acceptable, with participants valuing the opportunity to interact with others facing similar challenges. Session feedback indicated that 87.2% of participants agreed that the sessions had met their needs. Some indicated the desire for more ongoing support. Professionals felt that the intervention was under-resourced and questioned the long-term sustainability within current NHS settings. Professionals would have preferred greater access to participants' behaviour data to tailor the intervention better. The incremental cost-effectiveness ratio from the health-care perspective is £246,921 per quality-adjusted life-year (QALY) gained and the incremental cost-effectiveness ratio from the societal perspective is £367,543 per QALY gained. CONCLUSIONS: Despite the challenges of undertaking clinical research in this population, the trial successfully recruited and retained participants, indicating a high level of interest in weight management interventions; however, the STEPWISE intervention was neither clinically effective nor cost-effective. Further research will be required to define how overweight and obesity in people with schizophrenia should be managed. The trial results suggest that lifestyle programmes for people with schizophrenia may need greater resourcing than for other populations, and interventions that have been shown to be effective in other populations, such as people with diabetes mellitus, are not necessarily effective in people with schizophrenia. TRIAL REGISTRATION: Current Controlled Trials ISRCTN19447796. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 65. See the NIHR Journals Library website for further project information

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

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    Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies
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