220 research outputs found

    A value-added approach to determine the relationships of mentoring to novice teacher classroom effectiveness.

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    The purpose of the study was to determine the relationship between scores of the new teachers' classroom effectiveness with numerical indexes of mentor support, mentor infrastructure, and workplace ecology. In addition, this study sought to determine the effect of various demographics (i.e., gender, age, race, degree, teaching level, and certification route) on the Classroom Effectiveness Index (CEI) scores of first-year teachers, and to determine the differences, if any, between the Classroom Effectiveness Index scores of first-year teachers who remained on campus, switched campuses, or left the district. This study is primarily correlational in nature - looking for relationships between quantifiable variables. The subjects are 68 first-year teachers. The mandatory mentoring program the subjects were involved in consisted of a paid, veteran teacher who worked on the same campus as the first-year teacher and assisted in instructional or behavioral needs. This study measured the impact of the first-year teachers' mentoring experiences to the Classroom Effectiveness Index scores and teacher retention. The findings suggest that the Classroom Effectiveness Index scores might not be an appropriate tool for uncovering which aspects of mentoring contribute to student achievement and retention. Adding the value-added measurement tool to the categories of mentor support (MS), mentor infrastructure (MI), and workplace ecology (WE), rendered no statistically significant results. Therefore, further research is necessary to continue to define the effective characteristics of mentoring and its impact on classroom effectiveness and retention

    Association of Frequent Aspirin Use With Ovarian Cancer Risk According to Genetic Susceptibility

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    IMPORTANCE: Frequent aspirin use is associated with reduced ovarian cancer risk, but it is unknown whether genetic factors modify this association. Understanding effect modifiers is important given that any use of aspirin for ovarian cancer chemoprevention will likely need to focus on specific higher-risk subgroups. OBJECTIVE: To evaluate whether the association between frequent aspirin use and ovarian cancer is modified by a polygenic score (PGS) for nonmucinous ovarian cancer. DESIGN, SETTING, AND PARTICIPANTS: We pooled individual-level data from 8 population-based case-control studies from the Ovarian Cancer Association Consortium conducted in the US, UK, and Australia between 1995 and 2009. We included case patients and control participants with both genetic data and data on frequent aspirin use. Case patients with mucinous ovarian cancer were excluded. Data were analyzed between November 1, 2021, and July 31, 2022. EXPOSURES: Frequent aspirin use, defined as daily or almost daily use for 6 months or longer. MAIN OUTCOMES AND MEASURES: The main outcome was nonmucinous epithelial ovarian cancer. We used logistic regression to estimate odds ratios (ORs) and 95% CIs and likelihood ratio tests to investigate effect modification by the PGS. RESULTS: There were 4476 case patients with nonmucinous ovarian cancer and 6659 control participants included in this analysis. At study enrollment, the median (IQR) age was 58 (50-66) years for case patients and 57 (49-65) years for control participants. Case patients and control participants self-reported that they were Black (122 [3%] vs 218 [3%]), White (3995 [89%] vs 5851 [88%]), or of other race and ethnicity (348 [8%] vs 580 [9%]; race and ethnicity were unknown for 11 [0%] vs 10 [0%]). There were 575 case patients (13%) and 1030 control participants (15%) who reported frequent aspirin use. The 13% reduction in ovarian cancer risk associated with frequent aspirin use (OR, 0.87 [95% CI, 0.76-0.99]) was not modified by the PGS. Consistent ORs were observed among individuals with a PGS less than (0.85 [0.70-1.02]) and greater than (0.86 [0.74-1.01]) the median. Results were similar by histotype. CONCLUSIONS AND RELEVANCE: The findings of this study suggest that genetic susceptibility to ovarian cancer based on currently identified common genetic variants does not appear to modify the protective association between frequent aspirin use and ovarian cancer risk. Future work should continue to explore the role of aspirin use for ovarian cancer prevention among individuals who are at higher risk for ovarian cancer

    Maternal iron deficiency perturbs embryonic cardiovascular development in mice.

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    Congenital heart disease (CHD) is the most common class of human birth defects, with a prevalence of 0.9% of births. However, two-thirds of cases have an unknown cause, and many of these are thought to be caused by in utero exposure to environmental teratogens. Here we identify a potential teratogen causing CHD in mice: maternal iron deficiency (ID). We show that maternal ID in mice causes severe cardiovascular defects in the offspring. These defects likely arise from increased retinoic acid signalling in ID embryos. The defects can be prevented by iron administration in early pregnancy. It has also been proposed that teratogen exposure may potentiate the effects of genetic predisposition to CHD through gene-environment interaction. Here we show that maternal ID increases the severity of heart and craniofacial defects in a mouse model of Down syndrome. It will be important to understand if the effects of maternal ID seen here in mice may have clinical implications for women

    Prospective Associations of Coronary Heart Disease Loci in African Americans Using the MetaboChip: The PAGE Study

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    Background: Coronary heart disease (CHD) is a leading cause of morbidity and mortality in African Americans. However, there is a paucity of studies assessing genetic determinants of CHD in African Americans. We examined the association of published variants in CHD loci with incident CHD, attempted to fine map these loci, and characterize novel variants influencing CHD risk in African Americans. Methods and Results: Up to 8,201 African Americans (including 546 first CHD events) were genotyped using the MetaboChip array in the Atherosclerosis Risk in Communities (ARIC) study and Women's Health Initiative (WHI). We tested associations using Cox proportional hazard models in sex- and study-stratified analyses and combined results using meta-analysis. Among 44 validated CHD loci available in the array, we replicated and fine-mapped the SORT1 locus, and showed same direction of effects as reported in studies of individuals of European ancestry for SNPs in 22 additional published loci. We also identified a SNP achieving array wide significance (MYC: rs2070583, allele frequency 0.02, P = 8.1×10−8), but the association did not replicate in an additional 8,059 African Americans (577 events) from the WHI, HealthABC and GeneSTAR studies, and in a meta-analysis of 5 cohort studies of European ancestry (24,024 individuals including 1,570 cases of MI and 2,406 cases of CHD) from the CHARGE Consortium. Conclusions: Our findings suggest that some CHD loci previously identified in individuals of European ancestry may be relevant to incident CHD in African Americans

    Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

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    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology

    Keeping the Board in the Dark: CEO Compensation and Entrenchment

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    We study a model in which a CEO can entrench himself by hiding information from the board that would allow the board to conclude that he should be replaced. Assuming that even diligent monitoring by the board cannot fully overcome the information asymmetry visà- vis the CEO, we ask if there is a role for CEO compensation to mitigate the inefficiency. Our analysis points to a novel argument for high-powered, non-linear CEO compensation such as bonus pay or stock options. By shifting the CEO’s compensation into states where the firm’s value is highest, a high-powered compensation scheme makes it as unattractive as possible for the CEO to entrench himself when he expects that the firm’s future value under his management and strategy is low. This, in turn, minimizes the severance pay needed to induce the CEO not to entrench himself, thereby minimizing the CEO’s informational rents. Amongst other things, our model suggests how deregulation and technological changes in the 1980s and 1990s might have contributed to the rise in CEO pay and turnover over the same period

    A comprehensive gene-environment interaction analysis in Ovarian Cancer using genome-wide significant common variants.

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    As a follow-up to genome-wide association analysis of common variants associated with ovarian carcinoma (cancer), our study considers seven well-known ovarian cancer risk factors and their interactions with 28 genome-wide significant common genetic variants. The interaction analyses were based on data from 9971 ovarian cancer cases and 15,566 controls from 17 case-control studies. Likelihood ratio and Wald tests for multiplicative interaction and for relative excess risk due to additive interaction were used. The top multiplicative interaction was noted between oral contraceptive pill (OCP) use (ever vs. never) and rs13255292 (p value = 3.48 × 10-4 ). Among women with the TT genotype for this variant, the odds ratio for OCP use was 0.53 (95% CI = 0.46-0.60) compared to 0.71 (95%CI = 0.66-0.77) for women with the CC genotype. When stratified by duration of OCP use, women with 1-5 years of OCP use exhibited differential protective benefit across genotypes. However, no interaction on either the multiplicative or additive scale was found to be statistically significant after multiple testing correction. The results suggest that OCP use may offer increased benefit for women who are carriers of the T allele in rs13255292. On the other hand, for women carrying the C allele in this variant, longer (5+ years) use of OCP may reduce the impact of carrying the risk allele of this SNP. Replication of this finding is needed. The study presents a comprehensive analytic framework for conducting gene-environment analysis in ovarian cancer
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