18 research outputs found

    Transient amplifiers of selection and reducers of fixation for death-Birth updating on graphs

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    The spatial structure of an evolving population affects which mutations become fixed. Some structures amplify selection, increasing the likelihood that beneficial mutations become fixed while deleterious mutations do not. Other structures suppress selection, reducing the effect of fitness differences and increasing the role of random chance. This phenomenon can be modeled by representing spatial structure as a graph, with individuals occupying vertices. Births and deaths occur stochastically, according to a specified update rule. We study death-Birth updating: An individual is chosen to die and then its neighbors compete to reproduce into the vacant spot. Previous numerical experiments suggested that amplifiers of selection for this process are either rare or nonexistent. We introduce a perturbative method for this problem for weak selection regime, meaning that mutations have small fitness effects. We show that fixation probability under weak selection can be calculated in terms of the coalescence times of random walks. This result leads naturally to a new definition of effective population size. Using this and other methods, we uncover the first known examples of transient amplifiers of selection (graphs that amplify selection for a particular range of fitness values) for the death-Birth process. We also exhibit new families of "reducers of fixation", which decrease the fixation probability of all mutations, whether beneficial or deleterious.Comment: 51 pages, 5 figure

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

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    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    Alberta Gambling Research Institute Conference 2018: Current Issues in Gambling Research

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    The Alberta Gambling Research Institute's 17th Annual Conference "Current Issues in Gambling Research" took place April 12-14, 2018 @ The Banff Centre, Banff, Alberta, Canada. Opening reception the evening of April 12, 2018

    Critical Issues in Gambling Research: Alberta Gambling Research Institute's 14th Annual Conference

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    The Alberta Gambling Research Institute and the University of Lethbridge co-sponsored the fourteenth in a series of special interest conferences in the area of gambling studies. The conference theme was "Critical Issues in Gambling Research." The conference took place Friday, March 27, & Saturday, March 28, 2015 at the Banff Centre.Alberta Gambling Research Institut

    A longitudinal examination of mothers’ and fathers’ social information processing biases and harsh discipline in nine countries

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    This study examined whether parents’ social information processing was related to their subsequent reports of their harsh discipline. Interviews were conducted with mothers (n = 1,277) and fathers (n = 1,030) of children in 1,297 families in nine countries (China, Colombia, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States), initially when children were 7 to 9 years old and again 1 year later. Structural equation models showed that parents’ positive evaluations of aggressive responses to hypothetical childrearing vignettes at Time 1 predicted parents’ self-reported harsh physical and nonphysical discipline at Time 2. This link was consistent across mothers and fathers, and across the nine countries, providing support for the universality of the link between positive evaluations of harsh discipline and parents’ aggressive behavior toward children. The results suggest that international efforts to eliminate violence toward children could target parents’ beliefs about the acceptability and advisability of using harsh physical and nonphysical forms of discipline

    Polymer-Based Versus Polymer-Free Stents in High Bleeding Risk Patients: Final 2-Year Results From Onyx ONE

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    © 2022 American College of Cardiology FoundationBackground: Resolute Onyx polymer-based zotarolimus-eluting stents (ZES) were noninferior in safety and effectiveness to BioFreedom polymer-free biolimus A9-coated stents (DCS) in high-bleeding-risk (HBR) patients treated with 1-month dual antiplatelet therapy (DAPT) followed by single antiplatelet therapy (SAPT) at 1 year. Objectives: This study reports the final 2-year results of the randomized Onyx ONE trial. Methods: The Onyx ONE (A Randomized Controlled Trial With Resolute Onyx in One Month Dual Antiplatelet Therapy (DAPT) for High-Bleeding Risk Patients) trial randomly assigned HBR patients to treatment with ZES or DCS. Following 1-month DAPT, event-free patients received SAPT (either aspirin or a P2Y12 inhibitor at physician discretion). The primary safety endpoint, a composite of cardiac death, myocardial infarction, or stent thrombosis at 1 year, was determined at 1 year. Rates of primary and secondary endpoints were calculated after final follow-up at 2 years. Results: A total of 1,003 patients were randomly allocated to ZES and 993 patients to DCS. Follow-up was complete in 980 (97.7%) ZES patients and 962 (96.9%) DCS patients at 2 years. The primary safety endpoint occurred in 208 (21.2%) patients in the ZES group and 199 (20.7%) patients in the DCS group (risk difference: 0.5%; 95% CI: −3.1% to 4.2%; P = 0.78) at 2 years without significant differences in individual components of the composite endpoint. The secondary effectiveness endpoint occurred in 217 (22.1%) patients in the ZES group and 202 (21.0%) patients in the DCS group (risk difference: 1.1%; 95% CI: −2.5% to 4.8%; P = 0.54). Conclusions: Among patients at HBR treated with 1-month DAPT followed by SAPT, the Resolute Onyx polymer-based ZES had similar 2-year outcomes for the primary safety and secondary effectiveness endpoint compared with the BioFreedom polymer-free DCS. (A Randomized Controlled Trial With Resolute Onyx in One Month Dual Antiplatelet Therapy [DAPT] for High-Bleeding Risk Patients [Onyx ONE]; NCT03344653)N

    Polymer-Based Versus Polymer-Free Stents in High Bleeding Risk Patients: Final 2-Year Results From Onyx ONE.

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    BACKGROUND Resolute Onyx polymer-based zotarolimus-eluting stents (ZES) were noninferior in safety and effectiveness to BioFreedom polymer-free biolimus A9-coated stents (DCS) in high-bleeding-risk (HBR) patients treated with 1-month dual antiplatelet therapy (DAPT) followed by single antiplatelet therapy (SAPT) at 1 year. OBJECTIVES This study reports the final 2-year results of the randomized Onyx ONE trial. METHODS The Onyx ONE (A Randomized Controlled Trial With Resolute Onyx in One Month Dual Antiplatelet Therapy (DAPT) for High-Bleeding Risk Patients) trial randomly assigned HBR patients to treatment with ZES or DCS. Following 1-month DAPT, event-free patients received SAPT (either aspirin or a P2Y12 inhibitor at physician discretion). The primary safety endpoint, a composite of cardiac death, myocardial infarction, or stent thrombosis at 1 year, was determined at 1 year. Rates of primary and secondary endpoints were calculated after final follow-up at 2 years. RESULTS A total of 1,003 patients were randomly allocated to ZES and 993 patients to DCS. Follow-up was complete in 980 (97.7%) ZES patients and 962 (96.9%) DCS patients at 2 years. The primary safety endpoint occurred in 208 (21.2%) patients in the ZES group and 199 (20.7%) patients in the DCS group (risk difference: 0.5%; 95% CI: -3.1% to 4.2%; P = 0.78) at 2 years without significant differences in individual components of the composite endpoint. The secondary effectiveness endpoint occurred in 217 (22.1%) patients in the ZES group and 202 (21.0%) patients in the DCS group (risk difference: 1.1%; 95% CI: -2.5% to 4.8%; P = 0.54). CONCLUSIONS Among patients at HBR treated with 1-month DAPT followed by SAPT, the Resolute Onyx polymer-based ZES had similar 2-year outcomes for the primary safety and secondary effectiveness endpoint compared with the BioFreedom polymer-free DCS. (A Randomized Controlled Trial With Resolute Onyx in One Month Dual Antiplatelet Therapy [DAPT] for High-Bleeding Risk Patients [Onyx ONE]; NCT03344653)

    Respiratory support in patients with severe COVID-19 in the International Severe Acute Respiratory and Emerging Infection (ISARIC) COVID-19 study: a prospective, multinational, observational study

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    Background: Up to 30% of hospitalised patients with COVID-19 require advanced respiratory support, including high-flow nasal cannulas (HFNC), non-invasive mechanical ventilation (NIV), or invasive mechanical ventilation (IMV). We aimed to describe the clinical characteristics, outcomes and risk factors for failing non-invasive respiratory support in patients treated with severe COVID-19 during the first two years of the pandemic in high-income countries (HICs) and low middle-income countries (LMICs). Methods: This is a multinational, multicentre, prospective cohort study embedded in the ISARIC-WHO COVID-19 Clinical Characterisation Protocol. Patients with laboratory-confirmed SARS-CoV-2 infection who required hospital admission were recruited prospectively. Patients treated with HFNC, NIV, or IMV within the first 24 h of hospital admission were included in this study. Descriptive statistics, random forest, and logistic regression analyses were used to describe clinical characteristics and compare clinical outcomes among patients treated with the different types of advanced respiratory support. Results: A total of 66,565 patients were included in this study. Overall, 82.6% of patients were treated in HIC, and 40.6% were admitted to the hospital during the first pandemic wave. During the first 24 h after hospital admission, patients in HICs were more frequently treated with HFNC (48.0%), followed by NIV (38.6%) and IMV (13.4%). In contrast, patients admitted in lower- and middle-income countries (LMICs) were less frequently treated with HFNC (16.1%) and the majority received IMV (59.1%). The failure rate of non-invasive respiratory support (i.e. HFNC or NIV) was 15.5%, of which 71.2% were from HIC and 28.8% from LMIC. The variables most strongly associated with non-invasive ventilation failure, defined as progression to IMV, were high leukocyte counts at hospital admission (OR [95%CI]; 5.86 [4.83-7.10]), treatment in an LMIC (OR [95%CI]; 2.04 [1.97-2.11]), and tachypnoea at hospital admission (OR [95%CI]; 1.16 [1.14-1.18]). Patients who failed HFNC/NIV had a higher 28-day fatality ratio (OR [95%CI]; 1.27 [1.25-1.30]). Conclusions: In the present international cohort, the most frequently used advanced respiratory support was the HFNC. However, IMV was used more often in LMIC. Higher leucocyte count, tachypnoea, and treatment in LMIC were risk factors for HFNC/NIV failure. HFNC/NIV failure was related to worse clinical outcomes, such as 28-day mortality. Trial registration This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable
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