Sample records for black achievement gap
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The Black-White achievement gap: Do state policies matter?
Directory of Open Access Journals (Sweden)
Henry I. Braun
2006-03-01
Full Text Available A longstanding issue in American education is the gap in academic achievement between majority and minority students. The goal of this study is to accumulate and evaluate evidence on the relationship between state education policies and changes in the Black-White achievement gap, while addressing some of the methodological issues that have led to differences in interpretations of earlier findings. To that end, we consider the experiences of ten states that together enroll more than forty percent of the nation's Black students. We estimate the trajectories of Black student and White student achievement on the NAEP 8th grade mathematics assessment over the period 1992 to 2000, and examine the achievement gap at three levels of aggregation: the state as a whole, groups of schools (strata within a state defined by the SES level of the student population, and within schools within a stratum within a state. From 1992 to 2000, at every level of aggregation, mean achievement rose for both Black students and White students. However, for most states the achievement gaps were large and changed very little at every level of aggregation. The gaps are pervasive, profound and persistent. There is substantial heterogeneity among states in the types of policies they pursued, as well as the coherence and consistency of those policies during the period 1988-1998. We find that states' overall policy rankings (based on our review of the data correlate moderately with their record in improving Black student achievement but are somewhat less useful in predicting their record with respect to reducing the achievement gaps. States' rankings on commitment to teacher quality correlate almost as well as did the overall policy ranking. Thus, state reform efforts are a blunt tool, but a tool nonetheless. Our findings are consistent with the following recommendations: states' reform efforts should be built on broad-based support and buffered as much as possible from changes in
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The Achievement Gap: Factors That Influenced the Achievement of Successful Black Students
Morton, Kwame R., Sr.
2011-01-01
The academic underperformance of Black students when compared to their White peers has confounded educators nationwide. This discrepancy in academic performance commonly referred to as the achievement gap has become a national crisis which has led to one of the most significant educational reforms undertaken in the United States of America in the…
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The Dialectical Problematic of Resolving the Black-White Academic Achievement Gap and Climate Change
Mocombe, Paul C.
2018-01-01
In this article, I argue that resolving the Black-White academic achievement gap is incompatible with the emerging issues of global climate change. That is, solutions (equitable funding of schools and resources, school integration movements, and after-school and mentoring programs) for closing the gap in order so that Blacks in America and…
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School accountability and the black-white test score gap.
Gaddis, S Michael; Lauen, Douglas Lee
2014-03-01
Since at least the 1960s, researchers have closely examined the respective roles of families, neighborhoods, and schools in producing the black-white achievement gap. Although many researchers minimize the ability of schools to eliminate achievement gaps, the No Child Left Behind Act (NCLB) increased pressure on schools to do so by 2014. In this study, we examine the effects of NCLB's subgroup-specific accountability pressure on changes in black-white math and reading test score gaps using a school-level panel dataset on all North Carolina public elementary and middle schools between 2001 and 2009. Using difference-in-difference models with school fixed effects, we find that accountability pressure reduces black-white achievement gaps by raising mean black achievement without harming mean white achievement. We find no differential effects of accountability pressure based on the racial composition of schools, but schools with more affluent populations are the most successful at reducing the black-white math achievement gap. Thus, our findings suggest that school-based interventions have the potential to close test score gaps, but differences in school composition and resources play a significant role in the ability of schools to reduce racial inequality. Copyright © 2013 Elsevier Inc. All rights reserved.
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Structure of Black Male Students Academic Achievement in Science
Rascoe, Barbara
Educational policies and practices have been largely unsuccessful in closing the achievement gap between Black and White students "Schwartz, 2001". This achievement gap is especially problematic for Black students in science "Maton, Hrabrowski, - Schmitt, 2000. Given the fact that the Black-White achievement gap is still an enigma, the purpose of this article is to address the Black female-Black male academic achievement gap in science majors. Addressing barriers that Black male students may experience as college science and engineering majors, this article presents marketing strategies relative to politics, emotional intelligence, and issues with respect to how science teaching, and Black male students' responses to it, are different. Many Black male students may need to experience a paradigm shift, which structures and enhances their science achievement. Paradigm shifts are necessary because exceptional academic ability and motivation are not enough to get Black males from their first year in a science, technology, education, and mathematics "STEM" major to a bachelor's degree in science and engineering. The conclusions focus on the balance of truth-slippery slopes concerning the confluence of science teachers' further ado and Black male students' theories, methods, and values that position their academic achievement in science and engineering majors.
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School Segregation and Racial Academic Achievement Gaps
Directory of Open Access Journals (Sweden)
Sean F. Reardon
2016-09-01
Full Text Available Although it is clear that racial segregation is linked to academic achievement gaps, the mechanisms underlying this link have been debated since James Coleman published his eponymous 1966 report. In this paper, I examine sixteen distinct measures of segregation to determine which is most strongly associated with academic achievement gaps. I find clear evidence that one aspect of segregation in particular—the disparity in average school poverty rates between white and black students’ schools—is consistently the single most powerful correlate of achievement gaps, a pattern that holds in both bivariate and multivariate analyses. This implies that high-poverty schools are, on average, much less effective than lower-poverty schools and suggests that strategies that reduce the differential exposure of black, Hispanic, and white students to poor schoolmates may lead to meaningful reductions in academic achievement gaps.
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Black-White Achievement Gap and Family Wealth. National Poverty Center Working Paper Series #07-02
Yeung, W. Jean; Conley, Dalton
2006-01-01
This paper examines the extent to which family wealth affects the race-child achievement association for young children based on data from the Panel Study of Income Dynamics. We found little evidence that wealth mediates the black-white test scores gap. However, liquid assets, particularly holding in stocks and mutual funds, are positively…
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The Achievement Gap and the Discipline Gap: Two Sides of the Same Coin?
Gregory, Anne; Skiba, Russell J.; Noguera, Pedro A.
2010-01-01
The gap in achievement across racial and ethnic groups has been a focus of education research for decades, but the disproportionate suspension and expulsion of Black, Latino, and American Indian students has received less attention. This article synthesizes research on racial and ethnic patterns in school sanctions and considers how…
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Divergent Streams: Race-Gender Achievement Gaps at Selective Colleges and Universities
Massey, Douglas S.; Probasco, LiErin
2010-01-01
In this paper, we extend previous research on racial performance gaps at 28 selective US colleges and universities by examining differences in grade achievement and graduate rates across race-gender categories. Using data from the National Longitudinal Survey of Freshmen, we show that black males, black females, and Hispanic males attain significantly lower grades than other race-gender groups, and that black males are 35% less likely to graduate on-time than other race-gender groups. Analyse...
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Cultivating the Genius of Black Children: Strategies to Close the Achievement Gap in the Early Years
Sullivan, Debra Ren-Etta
2016-01-01
There has been much attention given to the opportunity gap between white and minority students, especially African American children. Using research and years of experience "Cultivating the Genius of Black Children" is able to break down the cultural influences on learning style and provides a practical approach to helping Black children…
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Mocombe, Paul C.
2015-01-01
This hermeneutical essay demonstrates why and how Pierre Bourdieu's social reproduction theory is neither an adequate explanation for understanding praxis nor the Black/White academic achievement gap in contemporary postindustrial economies like that of the United States and the United Kingdom. The underlining hypothesis of the work is that the…
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Divergent Streams: Race-Gender Achievement Gaps at Selective Colleges and Universities.
Massey, Douglas S; Probasco, Lierin
2010-03-01
In this paper, we extend previous research on racial performance gaps at 28 selective US colleges and universities by examining differences in grade achievement and graduate rates across race-gender categories. Using data from the National Longitudinal Survey of Freshmen, we show that black males, black females, and Hispanic males attain significantly lower grades than other race-gender groups, and that black males are 35% less likely to graduate on-time than other race-gender groups. Analyses consider an array of personal and institutional indicators of academic performance. Grades and graduation rates are improved by academic preparation (particularly high school GPA), scholarly effort, and, for graduation rates, membership in career-oriented or majority-white campus groups. Grade performance and graduation rates are undermined by a hostile racial climate on campus, family stress, and stereotype threat, all of which disproportionately affect minority students. We conclude with recommendations to college administrators for ways of selecting and supporting minority students to reduce differentials in academic achievement across race-gender groups.
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The theory-practice gap of black carbon mitigation technologies in rural China
Zhang, Weishi; Li, Aitong; Xu, Yuan; Liu, Junfeng
2018-02-01
Black carbon mitigation has received increasing attention for its potential contribution to both climate change mitigation and air pollution control. Although different bottom-up models concerned with unit mitigation costs of various technologies allow the assessment of alternative policies for optimized cost-effectiveness, the lack of adequate data often forced many reluctant explicit and implicit assumptions that deviate away from actual situations of rural residential energy consumption in developing countries, where most black carbon emissions occur. To gauge the theory-practice gap in black carbon mitigation - the unit cost differences that lie between what is estimated in the theory and what is practically achieved on the ground - this study conducted an extensive field survey and analysis of nine mitigation technologies in rural China, covering both northern and southern regions with different residential energy consumption patterns. With a special focus on two temporal characteristics of those technologies - lifetimes and annual utilization rates, this study quantitatively measured the unit cost gaps and explain the technical as well as sociopolitical mechanisms behind. Structural and behavioral barriers, which have affected the technologies' performance, are discussed together with policy implications to narrow those gaps.
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Racial residential segregation, socioeconomic disparities, and the White-Black survival gap
Duffy, Erin; Mendelsohn, Joshua; Escarce, José J.
2018-01-01
Objective To evaluate the association between racial residential segregation, a prominent manifestation of systemic racism, and the White-Black survival gap in a contemporary cohort of adults, and to assess the extent to which socioeconomic inequality explains this association. Design This was a cross sectional study of White and Black men and women aged 35–75 living in 102 large US Core Based Statistical Areas. The main outcome was the White-Black survival gap. We used 2009–2013 CDC mortality data for Black and White men and women to calculate age-, sex- and race adjusted White and Black mortality rates. We measured segregation using the Dissimilarity index, obtained from the Manhattan Institute. We used the 2009–2013 American Community Survey to define indicators of socioeconomic inequality. We estimated the CBSA-level White–Black gap in probability of survival using sequential linear regression models accounting for the CBSA dissimilarity index and race-specific socioeconomic indicators. Results Black men and women had a 14% and 9% lower probability of survival from age 35 to 75 than their white counterparts. Residential segregation was strongly associated with the survival gap, and this relationship was partly, but not fully, explained by socioeconomic inequality. At the lowest observed level of segregation, and with the Black socioeconomic status (SES) assumed to be at the White SES level scenario, the survival gap is essentially eliminated. Conclusion White-Black differences in survival remain wide notwithstanding public health efforts to improve life expectancy and initiatives to reduce health disparities. Eliminating racial residential segregation and bringing Black socioeconomic status (SES) to White SES levels would eliminate the White-Black survival gap. PMID:29474451
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Racial residential segregation, socioeconomic disparities, and the White-Black survival gap.
Directory of Open Access Journals (Sweden)
Ioana Popescu
Full Text Available To evaluate the association between racial residential segregation, a prominent manifestation of systemic racism, and the White-Black survival gap in a contemporary cohort of adults, and to assess the extent to which socioeconomic inequality explains this association.This was a cross sectional study of White and Black men and women aged 35-75 living in 102 large US Core Based Statistical Areas. The main outcome was the White-Black survival gap. We used 2009-2013 CDC mortality data for Black and White men and women to calculate age-, sex- and race adjusted White and Black mortality rates. We measured segregation using the Dissimilarity index, obtained from the Manhattan Institute. We used the 2009-2013 American Community Survey to define indicators of socioeconomic inequality. We estimated the CBSA-level White-Black gap in probability of survival using sequential linear regression models accounting for the CBSA dissimilarity index and race-specific socioeconomic indicators.Black men and women had a 14% and 9% lower probability of survival from age 35 to 75 than their white counterparts. Residential segregation was strongly associated with the survival gap, and this relationship was partly, but not fully, explained by socioeconomic inequality. At the lowest observed level of segregation, and with the Black socioeconomic status (SES assumed to be at the White SES level scenario, the survival gap is essentially eliminated.White-Black differences in survival remain wide notwithstanding public health efforts to improve life expectancy and initiatives to reduce health disparities. Eliminating racial residential segregation and bringing Black socioeconomic status (SES to White SES levels would eliminate the White-Black survival gap.
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Takahashi, Kazuaki; Takahashi, Kaori
2013-06-10
Japanese black bears, a large-bodied omnivore, frequently create small gaps in the tree crown during fruit foraging. However, there are no previous reports of black bear-created canopy gaps. To characterize physical canopy disturbance by black bears, we examined a number of parameters, including the species of trees in which canopy gaps were created, gap size, the horizontal and vertical distribution of gaps, and the size of branches broken to create gaps. The size of black bear-created canopy gaps was estimated using data from branches that had been broken and dropped on the ground. The disturbance regime was characterized by a highly biased distribution of small canopy gaps on ridges, a large total overall gap area, a wide range in gap height relative to canopy height, and diversity in gap size. Surprisingly, the annual rate of bear-created canopy gap formation reached 141.3 m2 ha-1 yr-1 on ridges, which were hot spots in terms of black bear activity. This rate was approximately 6.6 times that of tree-fall gap formation on ridges at this study site. Furthermore, this rate was approximately two to three times that of common tree-fall gap formation in Japanese forests, as reported in other studies. Our findings suggest that the ecological interaction between black bears and fruit-bearing trees may create a unique light regime, distinct from that created by tree falls, which increases the availability of light resources to plants below the canopy.
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The Politics of Achievement Gaps
DEFF Research Database (Denmark)
Valant, J.; Newark, D. A.
2016-01-01
on achievement gaps have received little attention from researchers, despite playing an important role in shaping policymakers’ behaviors. Drawing on randomized experiments with a nationally representative sample of adults, we explore the public’s beliefs about test score gaps and its support for gap...
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School Choice and the Achievement Gap
Jeynes, William H.
2014-01-01
The possibility is examined that school choice programs could be a means to reducing the achievement gap. Data based on meta-analytic research and the examination of nationwide data sets suggest that school choice programs that include private schools could reduce the achievement gap by 25%. The propounding of this possibility is based on research…
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Do Small Canopy Gaps Created by Japanese Black Bears Facilitate Fruiting of Fleshy-Fruited Plants?
Directory of Open Access Journals (Sweden)
Kazuaki Takahashi
Full Text Available Japanese black bears often break branches when climbing trees and feeding on fruit in canopies, thereby creating small canopy gaps. However, the role of black bear-created canopy gaps has not been evaluated in the context of multiple forest dynamics. Our hypothesis was that small canopy gaps created by black bears improve light conditions, which facilitates fruiting of adult fleshy-fruited plants located beneath the gaps, and also that this chain interaction depends on interactions among the size of gaps, improved light conditions, forest layers, and life form of plants. The rPPFD, size of black bear-created canopy gaps, and fruiting/non-fruiting of fleshy-fruited plants were investigated in five forest layers beneath black-bear-created canopy gaps and closed canopies of Mongolian oak (Quercus crispula. We found that light conditions improved beneath black bear-disturbed trees with canopy gaps of large size, and the effect of improvement of light conditions was reduced with descending forest layers. Fruiting of fleshy-fruited plants, especially woody lianas and trees, was facilitated by the improvement of light conditions accompanied by an increase in the size of black-bear-created gaps. Data from this study revealed that canopy disturbance by black bears was key for improving light conditions and accelerating fruiting of fleshy-fruited trees and woody lianas in the canopy layers in particular. Therefore, our hypothesis was mostly supported. Our results provide evidence that Japanese black bears have high potential as ecosystem engineers that increase the availability of resources (light and fruit in this study to other species by causing physical state changes in biotic materials (branches of Q. crispula in this study.
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Do Small Canopy Gaps Created by Japanese Black Bears Facilitate Fruiting of Fleshy-Fruited Plants?
Takahashi, Kazuaki; Takahashi, Kaori; Washitani, Izumi
2015-01-01
Japanese black bears often break branches when climbing trees and feeding on fruit in canopies, thereby creating small canopy gaps. However, the role of black bear-created canopy gaps has not been evaluated in the context of multiple forest dynamics. Our hypothesis was that small canopy gaps created by black bears improve light conditions, which facilitates fruiting of adult fleshy-fruited plants located beneath the gaps, and also that this chain interaction depends on interactions among the size of gaps, improved light conditions, forest layers, and life form of plants. The rPPFD, size of black bear-created canopy gaps, and fruiting/non-fruiting of fleshy-fruited plants were investigated in five forest layers beneath black-bear-created canopy gaps and closed canopies of Mongolian oak (Quercus crispula). We found that light conditions improved beneath black bear-disturbed trees with canopy gaps of large size, and the effect of improvement of light conditions was reduced with descending forest layers. Fruiting of fleshy-fruited plants, especially woody lianas and trees, was facilitated by the improvement of light conditions accompanied by an increase in the size of black-bear-created gaps. Data from this study revealed that canopy disturbance by black bears was key for improving light conditions and accelerating fruiting of fleshy-fruited trees and woody lianas in the canopy layers in particular. Therefore, our hypothesis was mostly supported. Our results provide evidence that Japanese black bears have high potential as ecosystem engineers that increase the availability of resources (light and fruit in this study) to other species by causing physical state changes in biotic materials (branches of Q. crispula in this study).
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School Desegregation and Black Achievement.
Cook, Thomas; And Others
Seven papers commissioned by the National Institute of Education in order to clarify the state of recent knowledge about the effects of school desegregation on the academic achievement of black students are contained in this report. The papers, which analyze 19 "core" empirical studies on this topic, include: (1) "What Have Black Children Gained…
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Quinn, David M.; Cooc, North
2015-01-01
Research on science achievement disparities by gender and race/ethnicity often neglects the beginning of the pipeline in the early grades. We address this limitation using nationally representative data following students from Grades 3 to 8. We find that the Black-White science test score gap (-1.07 SD in Grade 3) remains stable over these years,…
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Directory of Open Access Journals (Sweden)
Elisabeth Moores
2017-09-01
Full Text Available Ethnic minority groups have been shown to obtain poorer final year degree outcomes than their majority group counterparts in countries including the United States, the United Kingdom and The Netherlands. Obtaining a lower degree classification may limit future employment prospects of graduates as well as opportunities for higher level study. To further investigate this achievement gap, we analyzed performance levels across three academic years of study of 3,051 Black, Asian and White students from a United Kingdom University. Analyses of covariance investigated effects of ethnicity and work placement experience (internships on first, second and final year marks, whilst statistically controlling for a number of factors thought to influence achievement, including prior academic performance. Results demonstrated superior achievement of White students consistently across all years of study. Placement experience reduced, but did not eliminate, the size of the achievement gap exhibited by final year students. Sex, parental education and socioeconomic status had no significant main effects. Female students showed a more complex pattern of results than males, with Black females not showing the same final year uplift in marks as their Asian and White counterparts. Implications and possible explanations are discussed.
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Prince, Joan Marie
1999-12-01
Over the past years, progress in Black academic achievement, particularly in the area of science, has generally slowed or ceased. According to the 1994 NAEP assessment, twelfth-grade Black students are performing at the level of White eighth-grade students in the discipline of science (Department of Education, 1996). These students, in their last year of required schooling, are about to graduate, yet they lag at least four years behind their white counterparts in science achievement. Despite the establishment and implementation of numerous science intervention programs, Black students still suffer from a disparate gap in standardized test score achievement. The purpose of this research is to investigate teachers' perceptions of the effectiveness of an urban sciences intervention tool that was designed to assist in narrowing the Black-White science academic achievement gap. Specifically, what factors affect teachers' personal sense of instructional efficacy, and how does this translate into their outcome expectancy for student academic success? A multiple-case, replicative design, grounded in descriptive theory, was selected for the study. Multiple sources of evidence were queried to provide robust findings. These sources included a validated health sciences self-efficacy instrument, an interview protocol, a classroom observation, and a review of archival material that included case study participants' personnel files and meeting minutes. A cross-comparative analytic approach was selected for interpretation (Yin, 1994). Findings indicate that teachers attribute the success or failure of educational intervention tools in closing the Black-White test score gap to a variety of internal and external factors. These factors included a perceived lack of both monetary and personal support by the school leadership, as well as a perceived lack of parental involvement which impacted negatively on student achievement patterns. The case study participants displayed a depressed
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The Measured Black-White Wage Gap among Women Is Too Small.
Neal, Derek
2004-01-01
Existing work suggests that black-white gaps in potential wages are much larger among men than women and further that black-white differences in patterns of female labor supply are unimportant. However, panel data on wages and income sources demonstrate that the modal young black woman who does not engage in market work is a single mother…
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Martin, Nathan D.; Spenner, Kenneth I; Mustillo, Sarah A.
2017-01-01
In this study, we examined racial/ethnic differences in grade point average (GPA) among students at a highly selective, private university who were surveyed before matriculation and during the first, second and fourth college years, and assessed prominent explanations for the Black-White and Latino-White college achievement gap. We found that…
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Educational Achievement and Black-White Inequality. Statistical Analysis Report.
Jacobson, Jonathan; Olsen, Cara; Rice, Jennifer King; Sweetland, Stephen
This study explored relationships between black-white differences in educational achievement and black-white differences in various educational and economic outcomes. Three data sets examined the extent to which black-white differences in labor market outcomes, in educational attainment, and in mathematics and reading achievement were present for…
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Young, Jemimah L.; Young, Jamaal R.; Ford, Donna Y.
2017-01-01
The purpose of this study was to explore the differential effects of access to gifted education on the mathematics and science achievement of fourth-grade Black girls. This study utilized mean difference effect sizes to examine the magnitude of differences between groups. By convention, White girls were included as a comparison group. Girls…
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Rapidity gap survival in the black-disk regime
International Nuclear Information System (INIS)
Leonid Frankfurt; Charles Hyde; Mark Strikman; Christian Weiss
2007-01-01
We summarize how the approach to the black-disk regime (BDR) of strong interactions at TeV energies influences rapidity gap survival in exclusive hard diffraction pp -> p + H + p (H = dijet, Qbar Q, Higgs). Employing a recently developed partonic description of such processes, we discuss (a) the suppression of diffraction at small impact parameters by soft spectator interactions in the BDR; (b) further suppression by inelastic interactions of hard spectator partons in the BDR; (c) correlations between hard and soft interactions. Hard spectator interactions substantially reduce the rapidity gap survival probability at LHC energies compared to previously reported estimates
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The Widening Income Achievement Gap
Reardon, Sean F.
2013-01-01
Has the academic achievement gap between high-income and low-income students changed over the last few decades? If so, why? And what can schools do about it? Researcher Sean F. Reardon conducted a comprehensive analysis of research to answer these questions and came up with some striking findings. In this article, he shows that income-related…
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Explaining the black-white gap in cognitive test scores: Toward a theory of adverse impact.
Cottrell, Jonathan M; Newman, Daniel A; Roisman, Glenn I
2015-11-01
In understanding the causes of adverse impact, a key parameter is the Black-White difference in cognitive test scores. To advance theory on why Black-White cognitive ability/knowledge test score gaps exist, and on how these gaps develop over time, the current article proposes an inductive explanatory model derived from past empirical findings. According to this theoretical model, Black-White group mean differences in cognitive test scores arise from the following racially disparate conditions: family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors (maternal sensitivity, maternal warmth and acceptance, and safe physical environment), child birth order, and child birth weight. Results from a 5-wave longitudinal growth model estimated on children in the NICHD Study of Early Child Care and Youth Development from ages 4 through 15 years show significant Black-White cognitive test score gaps throughout early development that did not grow significantly over time (i.e., significant intercept differences, but not slope differences). Importantly, the racially disparate conditions listed above can account for the relation between race and cognitive test scores. We propose a parsimonious 3-Step Model that explains how cognitive test score gaps arise, in which race relates to maternal disadvantage, which in turn relates to parenting factors, which in turn relate to cognitive test scores. This model and results offer to fill a need for theory on the etiology of the Black-White ethnic group gap in cognitive test scores, and attempt to address a missing link in the theory of adverse impact. (c) 2015 APA, all rights reserved).
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Rapidity gap survival in the black-disk regime
International Nuclear Information System (INIS)
Leonid Frankfurt; Charles Hyde; Mark Strikman; Christian Weiss
2007-01-01
We summarize how the approach to the black-disk regime (BDR) of strong interactions at TeV energies influences rapidity gap survival in exclusive hard diffraction pp -> p + H + p (H = dijet, Qbar Q, Higgs). Employing a recently developed partonic description of such processes, we discuss (a) the suppression of diffraction at small impact parameters by soft spectator interactions in the BDR; (b) further suppression by inelastic interactions of hard spectator partons in the BDR; (c) effects of correlations between hard and soft interactions, as suggested by various models of proton structure (color fluctuations, spatial correlations of partons). Hard spectator interactions in the BDR substantially reduce the rapidity gap survival probability at LHC energies compared to previously reported estimates
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Solving the Achievement Gap: Overcoming the Structure of School Inequality
Yeh, Stuart S.
2017-01-01
This book examines the cause of the student achievement gap, suggesting that the prevailing emphasis on socioeconomic factors, sociocultural influences, and teacher quality is misplaced. The cause of the achievement gap is not differences in parenting styles, or the economic advantages of middle-class parents, or differences in the quality of…
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The Importance of Physical Activity in Closing the Achievement Gap
Burton, Laura J.; VanHeest, Jaci L.
2007-01-01
The most significant concern within the US educational community is the academic achievement gap. Investigation of the achievement gap reveals that minority students across all levels of education are not meeting the same academic measures as their non-Hispanic White peers. In addition, a disproportionate number of minority children are identified…
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Black Women in the Academy: The Secrets to Success and Achievement.
Gregory, Sheila T.
This book presents selected historical data focusing on three aspects in the lives of Black women: resilience of Black women and their families; strengths of the Black church and community; and formidable gains made by Black women in the workforce. The status and achievements of Black women professors and scholars in the academy are reviewed, with…
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Subgroup Achievement and Gap Trends: Hawaii
Center on Education Policy, 2010
2010-01-01
Hawaii showed improvement in reading and math in grade 8 at the basic, proficient, and advanced levels for Asian and white students, low income students, and boys and girls. Gains in math tended to be larger than in reading. Trends in closing achievement gaps were mixed. Comparable data were available from 2007 through 2009. (Contains 9 tables.)…
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School Counselors: Closing Achievement Gaps and Writing Results Reports
Hartline, Julie; Cobia, Debra
2012-01-01
Charged with closing the achievement gap for marginalized students, school counselors need to be able to identify gaps, develop interventions, evaluate effectiveness, and share results. This study examined 100 summary results reports submitted by school counselors after having received four days of training on the ASCA National Model. Findings…
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Valentino, Rachel
2018-01-01
Publicly funded pre-K is often touted as a means to narrow achievement gaps, but this goal is less likely to be achieved if poor and/or minority children do not, at a minimum, attend equal quality pre-K as their non-poor, non-minority peers. In this paper, I find large "quality gaps" in public pre-K between poor, minority students and…
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Kochanek, Kenneth D; Anderson, Robert N; Arias, Elizabeth
2015-11-01
Life expectancy at birth has increased steadily since 1900 to a record 78.8 years in 2013. But differences in life expectancy between the white and black populations still exist, despite a decrease in the life expectancy gap from 5.9 years in 1999 to 3.6 years in 2013. Differences in the change over time in the leading causes of death for the black and white populations have contributed to this decrease in the gap in life expectancy. Between 1999 and 2013, the decrease in the life expectancy gap between the black and white populations was mostly due to greater decreases in mortality from heart disease, cancer, HIV disease, unintentional injuries, and perinatal conditions among the black population. Similarly, the decrease in the gap between black and white male life expectancy was due to greater decreases in death rates for HIV disease, cancer, unintentional injuries, heart disease, and perinatal conditions in black males. For black females, greater decreases in diabetes death rates, combined with decreased rates for heart disease and HIV disease, were the major causes contributing to the decrease in the life expectancy gap with white females. The decrease in the gap in life expectancy between the white and black populations would have been larger than 3.6 years if not for increases in death rates for the black population for aortic aneurysm, Alzheimer’s disease, and maternal conditions. For black males, the causes that showed increases in death rates over white males were hypertension, aortic aneurysm, diabetes, Alzheimer’s disease, and kidney disease, while the causes that showed increases in death rates for black females were Alzheimer’s disease, maternal conditions, and atherosclerosis. This NCHS Data Brief is the second in a series of data briefs that explore the causes of death contributing to differences in life expectancy between detailed ethnic and racial populations in the United States. The first data brief focused on the racial differences in life
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Directory of Open Access Journals (Sweden)
Henry Braun
2010-09-01
Full Text Available This study examines trends in Black student achievement and in the Black-White achievement gap over the period 2000 to 2007, employing data from ten states drawn from the NAEP Grade 8 mathematics assessments. Results are obtained for three levels of aggregation: the state, school poverty stratum within the state, and schools within poverty stratum. In addition, information on the ten states’ education policies for the period 1998 to 2005 was compiled. States relative ranks on the overall strength of their reform efforts were compared to their relative ranks with respect to their success in improving Black student achievement and in reducing the Black- White achievement gap. This study constitutes an extension of earlier work that considered the same issues for the period 1992 to 2000 and, thus, offers a unique comparison between the pre-NCLB era and the present one. Although the ten states certainly differed in their outcomes, the general picture at all three levels of aggregation is quite clear: The achievement gaps are substantial and the introduction of federally mandated high stakes test-based accountability through No Child Left Behind has had a very modest impact on the rates of improvement for Black students and on the pace of reductions in the achievement gaps between Black students and White students. Moreover, there was only a weak association between states’ policy rankings and their rankings related to test results. It appears there is a need for both fresh thinking on education reform and a more concerted effort to collect comprehensive longitudinal information on states' education policies.
Este estudio examina las tendencias en el rendimiento académico de estudiantes negros y la brecha en el rendimiento de los estudiantes negros y blancos en el período 2000 a 2007, utilizando datos de las evaluaciones NAEP de Matemáticas para el octavo grado en diez estados. Se obtuvieron resultados para tres niveles de agregacio
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The Achievement Gap in Reading: Complex Causes, Persistent Issues, Possible Solutions
Horowitz, Rosalind, Ed.; Samuels, S. Jay, Ed.
2017-01-01
In this volume prominent scholars, experts in their respective fields and highly skilled in the research they conduct, address educational and reading research from varied perspectives and address what it will take to close the achievement gap--with specific attention to reading. The achievement gap is redefined as a level at which all groups can…
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Patterns of Change in U.S. Gender Achievement Gaps during Elementary and Middle School
Fahle, Erin
2016-01-01
Research on gender achievement gaps shows they exist, and are largest in the tails of the distribution, starting as early as Kindergarten and persisting through eighth grade. In mathematics, studies find small average gender achievement gaps and larger systematically male-favoring gaps among the highest achieving students. This paper seeks to…
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Test Format and the Variation of Gender Achievement Gaps within the United States
Reardon, Sean; Fahle, Erin; Kalogrides, Demetra; Podolsky, Anne; Zarate, Rosalia
2016-01-01
Prior research demonstrates the existence of gender achievement gaps and the variation in the magnitude of these gaps across states. This paper characterizes the extent to which the variation of gender achievement gaps on standardized tests across the United States can be explained by differing state accountability test formats. A comprehensive…
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School Personnel-Student Racial Congruence and the Achievement Gap
Moore, Allison B.; MacGregor, Cynthia; Cornelius-White, Jeffrey
2017-01-01
Purpose: This paper aims to examine the relationship between student achievement and racial congruence of school personnel and students to help educators and policy makers narrow the achievement gap. Design/methodology/approach: This quasi-experimental, correlational study used publicly available data from 158 elementary schools in the Houston…
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Teacher qualification and the achievement gap in early primary grades.
Directory of Open Access Journals (Sweden)
Donald Easton-Brooks
2009-08-01
Full Text Available Title I of the No Child Left Behind Act (P.L. 107-110, 115 Stat. 1245, 2002 holds schools accountable for reducing the academic achievement gap between the different ethnic groups and requires elementary school teachers to have at least a bachelors degree and a state certification. The purpose of this study was to examine the relationship of the qualification requirement of NCLB to the goal of reducing the academic achievement gap. The study found that students with a certified teacher for most of their early school experience scored higher in reading than students who did not have a certified teacher. In addition, certification was associated with slightly narrowing the academic gap between African American and European American students across early elementary grades.
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The Gender and Race Composition of Jobs and the Male/Female, White/Black Pay Gaps.
Tomaskovic-Devey, Donald
1993-01-01
Analysis of North Carolina survey data indicates that females' average hourly wages were 71% of males', and blacks' wages were 78% of whites'. Human capital factors (educational attainment and occupational experience) explained 31% and 3% of the racial and gender gaps, respectively. Job gender composition explained 56% of the gender gap; job…
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Tung, Rosann; Carlo, Vivian Dalila; Colón, Melissa; Del Razo, Jaime L.; Diamond, John B.; Raynor, Alethea Frazier; Graves, Daren; Kuttner, Paul J.; Miranda, Helena; St. Rose, Andresse
2015-01-01
Boston Public Schools (BPS) commissioned companion studies as part of its efforts to address achievement gaps for Black and Latino males. The first study revealed the increasing diversity of Black and Latino males and stark opportunity gaps throughout the system that contribute in large part to wide attainment gaps for these students. We…
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Anomalous Temperature Dependence of the Band Gap in Black Phosphorus
Villegas, Cesar E. P.; Rocha, A. R.; Marini, Andrea
2016-01-01
Black Phosphorus (BP) has gained renewed attention due to its singular anisotropic electronic and optical properties that might be exploited for a wide range of technological applications. In this respect, the thermal properties are particularly important both to predict its room temperature operation and to determine its thermoelectric potential. From this point of view, one of the most spectacular and poorly understood phenomena is, indeed, the BP temperature-induced band-gap opening: when ...
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Education in the United States: Is It a Black Problem?
Comeaux, Eddie; Jayakumar, Uma M.
2007-01-01
This review offers a critical analysis of John Ogbu's "Black American Students in an Affluent Suburb: A study of academic disengagement." In his study, Ogbu explains the Black-White achievement gap as one born from the cultural attitudes held by Black middle-class students toward academics. Despite Ogbu's intent to further the scholarly…
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The New Literacies of Online Research and Comprehension: Rethinking the Reading Achievement Gap
Leu, Donald J.; Forzani, Elena; Rhoads, Chris; Maykel, Cheryl; Kennedy, Clint; Timbrell, Nicole
2015-01-01
Is there an achievement gap for online reading ability based on income inequality that is separate from the achievement gap in traditional, offline reading? This possibility was examined between students in two pseudonymous school districts: West Town (economically advantaged) and East Town (economically challenged; N = 256). Performance-based…
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Aggression and violence and the achievement gap among urban minority youth.
Basch, Charles E
2011-10-01
To outline the prevalence and disparities of aggression and violence among school-aged urban minority youth, causal pathways through which aggression and violence adversely affects academic achievement, and proven or promising approaches for schools to address these problems. Literature review. Recent national data indicate that among students aged 12-18, approximately 628,200 violent crimes and 868,100 thefts occurred. Physical fighting was more commonly reported by Blacks and Hispanics (44.7% and 40.4%, respectively) than Whites (31.7%). In-school threats and injuries were nearly twice as prevalent in cities as in suburbs and towns or rural areas (10% vs 6% and 5%, respectively). Associations between exposure to and exhibition of aggression and violence and unfavorable educational outcomes are well documented. Causal pathways through which aggression and violence impede learning include cognition, school connectedness, and absenteeism. Disruptive classroom behavior is a well-recognized and significant impediment to teaching and learning. Compelling research has shown that various school-based programs can significantly reduce the nature and extent of aggressive and violent behaviors. Violence and aggressive behavior are highly and disproportionately prevalent among school-aged urban minority youth, have a negative impact on academic achievement by adversely affecting cognition, school connectedness, and absenteeism, and effective practices are available for schools to address this problem. Once the domain of criminal justice, aggression and violence are now recognized as an appropriate and important focus of the education and public health systems. Implementing evidence-based school policies and programs to reduce aggression and violence must be a high priority to help close the achievement gap. © 2011, American School Health Association.
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Self-Esteem and Achievement of At-Risk Adolescent Black Males.
Howerton, D. Lynn; And Others
The relationship between self-esteem and academic achievement of at-risk adolescent black males was studied for 42 students in grades 6, 7, and 8. The Coopersmith Self-Esteem Inventory (SEI) was used to provide global measures of self-esteem. School grades and scores from the Stanford Achievement Test battery were used to measure academic…
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Racial Differences in Access to High-Paying Jobs and the Wage Gap between Black and White Women.
Anderson, Deborah; Shapiro, David
1996-01-01
Data from black and white women ages 34-44 (1968-88) showed that differences in characteristics did not explain occupational segregation by race nor the racial wage gap. During the 1980s, the gap was influenced by widening differences in access to occupations and an increase in returns to education. (SK)
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Race and Color: Revisiting Perspectives in Black Education
Monroe, Carla R.
2016-01-01
Racial inequities, such as systematic disparities in school discipline and achievement outcomes, are a perennial characteristic of public education in the United States. Although attention to interracial chasms such as the Black-White achievement gap is common, limited efforts are devoted to understanding how and why colorism motivates imbalances…
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Directory of Open Access Journals (Sweden)
Quaylan Allen
2010-05-01
Full Text Available The literature on Black education has often neglected significant analysis of life in schools and the experience of racism among Black middle-class students in general and Black middle-class males specifically. Moreover, the achievement gap between this population and their White counterparts in many cases is greater than the gap that exists among working-class Blacks and Whites. This study begins to document the aforementioned by illuminating the racial microaggressions experienced by Black middle-class males while in school and how their families’ usage of social and cultural capital deflect the potential negative outcomes of school racism.
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Royle, Jonathan; Brown, Casey Graham
2014-01-01
This study included an analysis of principal perceptions of the achievement gap between African American and White students. School administrators from campuses with a substantial number of African American students within the subgroup were interviewed to explore their perceptions of the achievement gap. The study revealed factors within the…
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Single Black Working Mothers' Perceptions: The Journey to Achieve Leadership Positions
Raglin, Sherrell
2017-01-01
Single Black working mothers faced significant challenges in achieving high-level or senior-level leadership positions. The purpose of this qualitative narrative study was to collect, analyze and code the stories told by 10 participants to understand the perceptions and insights of the challenges and barriers single Black working mothers faced in…
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Income Segregation between School Districts and Inequality in Students' Achievement
Owens, Ann
2018-01-01
Large achievement gaps exist between high- and low-income students and between black and white students. This article explores one explanation for such gaps: income segregation between school districts, which creates inequality in the economic and social resources available in advantaged and disadvantaged students' school contexts. Drawing on…
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Becker, Bronwyn E.; Luthar, Suniya S.
2002-01-01
Despite concentrated efforts at improving inferior academic outcomes among disadvantaged students, a substantial achievement gap between the test scores of these students and others remains (Jencks & Phillips, 1998; National Center for Education Statistics, 2000a, 2000b; Valencia & Suzuki, 2000). Existing research used ecological models to document social–emotional factors at multiple levels of influence that undermine academic performance. This article integrates ideas from various perspecti...
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Decomposing Black-White Wage Gaps Across Distributions: Young U.S. Men and Women in 1990 vs. 2011
Richey, Jeremiah; Tromp, Nikolas
2016-01-01
We investigate changes in black-white wage gaps across wage distributions for young men and women in the U.S. between 1990 and 2011. Gaps are decomposed into composition and structural effects using a semi-parametric framework. Further, we investigate the roles of occupational choice and self-selection. We find a fall in the composition effect shrinks the wage gap at the lower end of the distribution for men and women. Conversely, an increase in the composition effect for men, and...
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Potential economic impacts of achieving good environmental status in Black Sea fisheries
Directory of Open Access Journals (Sweden)
Ian C. Goulding
2014-09-01
Full Text Available The Marine Strategy Framework Directive (MSFD mandates that European Union (EU member states achieve Good Environmental Status (GEnS based on an ecosystem-based approach to management. For commercial fisheries, the primary target under the MSFD is one of maximum sustainable yield. Of Black Sea riparian nations, only Romania and Bulgaria are EU member states. Focusing at the supranational level, we review institutions and instruments relevant to management of the Black Sea. The economic values of current fish catches are assessed, and the results of a recent analytical assessment of fish stocks are used to estimate potential future values based on maximum sustainable yields. In the Black Sea region, despite long-standing attempts to improve fisheries management, there remains a lack of effective regional cooperation. Evidence from the scenario analysis suggests that achieving GEnS would not have an undue negative impact on overall fishery sector incomes, and could, with appropriate investments in processing and marketing, deliver increased economic benefits for Black Sea countries. The ongoing policy debate between and within Black Sea coastal states needs to be extended to include recognition of the potential economic and social benefits of effective fisheries management. More work is required to assess returns on investment in interim management measures to deliver GEnS.
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Directory of Open Access Journals (Sweden)
Kevin M. Gorey
2009-12-01
Full Text Available This meta-analysis extends a previous review of the achievement effects of comprehensive school reform (CSR programs (Borman, Hewes, Overman, & Brown, 2003. That meta-analysis observed significant effects of well endowed and well-researched programs, but it did not account for race/ethnicity. This article synthesizes 34 cohort or quasi-experimental outcomes of studies that incorporated the policy-critical characteristic of race/ethnicity. Findings: compared with matched traditional schools, the black-white achievement gap narrowed significantly more among students in CSR schools. In addition, the aggregate effects were large, substantially to completely eliminating the achievement gap between African American and non-Hispanic white students in elementary and middle schools. Title I policies before or after the No Child Left Behind Act of 2001 seem to have had essentially no impact on the black-white achievement gap. Curricular and testing mandates along with the threat of sanctions without concomitant resource supports seem to have failed. This study suggests that educational achievement inequities need not be America’s destiny. It seems that they could be eliminated through concerted political will and ample resource commitments to evidence-based educational programs. Este meta-análisis extiende una revisión previa de los efectos de realización de programas de reforma escolar integral (RSI, (Borman, Hewes, Overman, & Brown, 2003. Esa meta-análisis observo efectos significativos de programas con buen financiamiento y debidamente investigados, pero no tomó en cuenta los factores raciales o étnicos. En este artículo se sintetizan 34 resultados de estudios de cohorte o cuasi-experimental que incorporaron la característica política esencial de raza/origen étnico. Resultados: en comparación con escuelas tradicionales, la brecha de rendimiento entre estudiantes blancos y negros se redujo significativamente mas en escuelas RSI. Adem
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Geographic Variation of District-Level Gender Achievement Gaps within the United States
Reardon, Sean; Fahle, Erin; Kalogrides, Demetra; Podolsky, Anne; Zarate, Rosalia
2016-01-01
Gender achievement gaps on national and state assessments have been a popular research topic over the last few decades. Many prior studies examine these gaps in different subjects (e.g., mathematics, reading, and science) and grades (typically kindergarten through eighth grade) for students living in various regions (typically states or countries)…
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Black Girls' Achievement in Middle Grades Mathematics: How Can Socializing Agents Help?
Young, Jemimah L.; Young, Jamaal Rashad; Capraro, Mary Margaret
2017-01-01
The middle grades mathematics classroom is full of transitions that students must overcome to become successful long-term learners of mathematics. This transition can be exorbitantly more tumultuous for Black girls who must overcome gender and racial mathematics achievement stereotypes. Mathematics identities and achievement socialization trends…
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Minding the Achievement Gap One Classroom at a Time
Pollock, Jane E.; Ford, Sharon; Black, Margaret M.
2012-01-01
Do teachers have the power to close achievement gaps? Here's a book that boldly claims they do and lays out a blueprint for how to do something now to help students who are falling short of standards. Regardless of the student population you need to address--English language learners, special education, or just the unmotivated and hard to…
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Directory of Open Access Journals (Sweden)
Madhabi Chatterji
2005-11-01
Full Text Available In light of the NCLB Act of 2001, this study estimated mathematics achievement gaps in different subgroups of kindergartners and first graders, and identified child- and school-level correlates and moderators of early mathematics achievement. A subset of 2300 students nested in 182 schools from the Early Childhood Longitudinal Study K-First Grade data set was analyzed with hierarchical linear models. Relative to school mean estimates at the end of kindergarten, significant mathematics achievement gaps were found in Hispanics, African Americans and high poverty students. At the end of Grade 1, mathematics gaps were significant in African American, high poverty, and female subgroups, but not in Hispanics. School-level correlates of Grade 1 Mathematics achievement were class size (with a small negative main effect, at-home reading time by parents (with a large positive main effect and school size (with a small positive main effect. Cross-level interactions in Grade 1 indicated that schools with larger class and school sizes had a negative effect on African American children's math scores; schools giving more instructional time to reading and math had a positive effect on high poverty students' scores, and schools with higher elementary teacher certification rates had a positive effect on boys' mathematics achievement.
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Linking Communalism to Achievement Correlates for Black and White Undergraduates
Tyler, Kenneth; Love, Keisha; Brown, Carrie; Roan-Belle, Clarissa; Thomas, Deneia; Garriott, Patton O.
2010-01-01
This study examined relationships between home-based communal activities and beliefs and student reports of various achievement correlates with 290 black and white undergraduates. MANOVA procedures examined differences in self-esteem, self-efficacy, identified motivation, motivation to know, and amotivation and scores on Home Communalism Measure…
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Becker, Bronwyn E; Luthar, Suniya S
2002-01-01
Despite concentrated efforts at improving inferior academic outcomes among disadvantaged students, a substantial achievement gap between the test scores of these students and others remains (Jencks & Phillips, 1998; National Center for Education Statistics, 2000a, 2000b; Valencia & Suzuki, 2000). Existing research used ecological models to document social-emotional factors at multiple levels of influence that undermine academic performance. This article integrates ideas from various perspectives in a comprehensive and interdisciplinary model that will inform policy makers, administrators, and schools about the social-emotional factors that act as both risk and protective factors for disadvantaged students' learning and opportunities for academic success. Four critical social-emotional components that influence achievement performance (academic and school attachment, teacher support, peer values, and mental health) are reviewed.
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WFH: closing the global gap--achieving optimal care.
Skinner, Mark W
2012-07-01
For 50 years, the World Federation of Hemophilia (WFH) has been working globally to close the gap in care and to achieve Treatment for All patients, men and women, with haemophilia and other inherited bleeding disorders, regardless of where they might live. The WFH estimates that more than one in 1000 men and women has a bleeding disorder equating to 6,900,000 worldwide. To close the gap in care between developed and developing nations a continued focus on the successful strategies deployed heretofore will be required. However, in response to the rapid advances in treatment and emerging therapeutic advances on the horizon it will also require fresh approaches and renewed strategic thinking. It is difficult to predict what each therapeutic advance on the horizon will mean for the future, but there is no doubt that we are in a golden age of research and development, which has the prospect of revolutionizing treatment once again. An improved understanding of "optimal" treatment is fundamental to the continued evolution of global care. The challenges of answering government and payer demands for evidence-based medicine, and cost justification for the introduction and enhancement of treatment, are ever-present and growing. To sustain and improve care it is critical to build the body of outcome data for individual patients, within haemophilia treatment centers (HTCs), nationally, regionally and globally. Emerging therapeutic advances (longer half-life therapies and gene transfer) should not be justified or brought to market based only on the notion that they will be economically more affordable, although that may be the case, but rather more importantly that they will be therapeutically more advantageous. Improvements in treatment adherence, reductions in bleeding frequency (including microhemorrhages), better management of trough levels, and improved health outcomes (including quality of life) should be the foremost considerations. As part of a new WFH strategic plan
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Narrowing the Achievement Gap: A Review of Research, Policies, and Issues. Report.
Hertert, Linda; Teague, Jackie
Student achievement tests consistently show that certain groups of children score far below children in other groups. The data document a strong association between poverty and students' academic success. The achievement gap begins early in children's lives as the result of physical, social, and emotional deprivations. California is attempting to…
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Closing the Social Class Achievement Gap for First-Generation Students in Undergraduate Biology
Harackiewicz, Judith M.; Canning, Elizabeth A.; Tibbetts, Yoi; Giffen, Cynthia J.; Blair, Seth S.; Rouse, Douglas I.; Hyde, Janet S.
2014-01-01
Many students start college intending to pursue a career in the biosciences, but too many abandon this goal because they struggle in introductory biology. Interventions have been developed to close achievement gaps for underrepresented minority students and women, but no prior research has attempted to close the gap for first-generation students,…
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Expanding METCO and Closing Achievement Gaps. White Paper No. 129
Apfelbaum, Katherine; Ardon, Ken
2015-01-01
School systems around the United States are heavily segregated by income and race. At the same time, an achievement gap between white and nonwhite students persists despite many efforts to close it. Against this background, in this white paper the authors explore the history and successes of the Metropolitan Council for Educational Opportunity…
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Why the racial gap in life expectancy is declining in the United States
Firebaugh, Glenn; Acciai, Francesco; Noah, Aggie J.; Prather, Christopher; Nau, Claudia
2014-01-01
BACKGROUND Blacks have lower life expectancy than whites in the United States. That disparity could be due to racial differences in the causes of death, with blacks being more likely to die of causes that affect the young, or it could be due to differences in the average ages of blacks and whites who die of the same cause. Prior studies fail to distinguish these two possibilities. OBJECTIVE In this study we determine how much of the 2000–10 reduction in the racial gap in life expectancy resulted from narrowing differences in the cause-specific mean age at death for blacks and whites, as opposed to changing cause-specific probabilities for blacks and whites. METHOD We introduce a method for separating the difference-in-probabilities and difference-inage components of group disparities in life expectancy. RESULTS Based on the new method, we find that 60% of the decline in the racial gap in life expectancy from 2000 to 2010 was attributable to reduction in the age component, largely because of declining differences in the age at which blacks and whites die of chronic diseases. CONCLUSION Our findings shed light on the sources of the declining racial gap in life expectancy in the United States, and help to identify where advances need to be made to achieve the goal of eliminating racial disparities in life expectancy. PMID:25580083
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Why the racial gap in life expectancy is declining in the United States
Directory of Open Access Journals (Sweden)
Glenn Firebaugh
2014-10-01
Full Text Available Background: Blacks have lower life expectancy than whites in the United States. That disparity could be due to racial differences in the causes of death, with blacks being more likely to die of causes that affect the young, or it could be due to differences in the average ages of blacks and whites who die of the same cause. Prior studies fail to distinguish these two possibilities. Objective: In this study we determine how much of the 2000-10 reduction in the racial gap in life expectancy resulted from narrowing differences in the cause-specific mean age at death for blacks and whites, as opposed to changing cause-specific probabilities for blacks and whites. Methods: We introduce a method for separating the difference-in-probabilities and difference-in-age components of group disparities in life expectancy. Results: Based on the new method, we find that 60Š of the decline in the racial gap in life expectancy from 2000 to 2010 was attributable to reduction in the age component, largely because of declining differences in the age at which blacks and whites die of chronic diseases. Conclusions: Our findings shed light on the sources of the declining racial gap in life expectancy in the United States, and help to identify where advances need to be made to achieve the goal of eliminating racial disparities in life expectancy.
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Friend Effects and Racial Disparities in Academic Achievement
Directory of Open Access Journals (Sweden)
Jennifer Flashman
2014-07-01
Full Text Available Racial disparities in achievement are a persistent fact of the US educational system. An often cited but rarely directly studied explanation for these disparities is that adolescents from different racial and ethnic backgrounds are exposed to different peers and have different friends. In this article I identify the impact of friends on racial and ethnic achievement disparities. Using data from Add Health and an instrumental variable approach, I show that the achievement characteristics of youths’ friends drive friend effects; adolescents with friends with higher grades are more likely to increase their grades compared to those with lower-achieving friends. Although these effects do not differ across race/ethnicity, given differences in friendship patterns, if black and Latino adolescents had friends with the achievement characteristics of white students, the GPA gap would be 17 to 19 percent smaller. Although modest, this effect represents an important and often overlooked source of difference among black and Latino youth.
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Thurlow, Martha L.; Wu, Yi-Chen; Lazarus, Sheryl S.; Ysseldyke, James E.
2016-01-01
Federal regulations indicate that the achievement gap must be closed between subgroups, including the gap between special education and non-special education students. We explored the ways in which achievement trends are influenced by three methods of reporting (cross-sectional, cohort-static, and cohort-dynamic). We also investigated (a) the ways…
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An Examination of Effective Practice: Moving Toward Elimination of Achievement Gaps in Science
Johnson, Carla C.
2009-06-01
This longitudinal study of middle school science teachers explored the relationship between effective science instruction, as defined by the National Science Education Standards (NRC in National science education standards. National Academy Press, Washington, DC, 1996), and student achievement in science. Eleven teachers participated in a three year study of teacher effectiveness, determined by the LSC Classroom Observation Protocol (Horizon Research, Inc. in Local Systemic Change Classroom Observation Protocol. May 1, 2002) and student achievement, which was assessed using the Discovery Inquiry Test in Science. Findings in this study revealed the positive impact that effective science teachers have on student learning, eliminating achievement gaps between White and Non-White students. Case studies of three teachers, both effective and ineffective explore the beliefs and experiences that influence teachers to change, or not to change practice. This study provides justification for teaching science effectively to narrow achievement gaps in science and provides insight to stakeholders in science education as to how to support teachers in becoming more effective, through addressing existing teacher beliefs and providing experiences that challenge those beliefs.
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The Relationship between Black Racial Identity and Academic Achievement in Urban Settings
Harper, Brian E.
2007-01-01
This article examines the relationship between Black racial identity and academic achievement in urban settings. Using Mary Shelley's Frankenstein (1918) as a comparative framework, the author describes current practices and suggests practical applications of empirical findings for practicing classroom teachers of African American students.…
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Sizes of Black Holes Throughout the Universe
Kohler, Susanna
2018-05-01
What is the distribution of sizes of black holes in our universe? Can black holes of any mass exist, or are there gaps in their possible sizes? The shape of this black-hole mass function has been debated for decades and the dawn of gravitational-wave astronomy has only spurred further questions.Mind the GapsThe starting point for the black-hole mass function lies in the initial mass function (IMF) for stellar black holes the beginning size distribution of black holes after they are born from stars. Instead of allowing for the formation of stellar black holes of any mass, theoretical models propose two gaps in the black-hole IMF:An upper mass gap at 50130 solar masses, due to the fact that stellar progenitors of black holes in this mass range are destroyed by pair-instability supernovae.A lower mass gap below 5 solar masses, which is argued to arise naturally from the mechanics of supernova explosions.Missing black-hole (BH) formation channels due to the existence of the lower gap (LG) and the upper gap (UG) in the initial mass function. a) The number of BHs at all scales are lowered because no BH can merge with BHs in the LG to form a larger BH. b) The missing channel responsible for the break at 10 solar masses, resulting from the LG. c) The missing channel responsible for the break at 60 solar masses, due to the interaction between the LG and the UG. [Christian et al. 2018]We can estimate the IMF for black holes by scaling a typical IMF for stars and then adding in these theorized gaps. But is this initial distribution of black-hole masses the same as the distribution that we observe in the universe today?The Influence of MergersBased on recent events, the answer appears to be no! Since the first detections of gravitational waves in September 2015, we now know that black holes can merge to form bigger black holes. An initial distribution of black-hole masses must therefore evolve over time, as mergers cause the depletion of low-mass black holes and an increase in
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Understanding Science Achievement Gaps by Race/Ethnicity and Gender in Kindergarten and First Grade
Curran, F. Chris; Kellogg, Ann T.
2016-01-01
Disparities in science achievement across race and gender have been well documented in secondary and postsecondary school; however, the science achievement gap in the early years of elementary school remains understudied. We present findings from the recently released Early Childhood Longitudinal Study, Kindergarten Class of 2010-2011 that…
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Gender Gap Linked to Differential Socialization for High-Achieving Senior Mathematics Students.
Campbell, James R.; Beaudry, Jeffrey S.
1998-01-01
Examined whether 11th-grade girls and boys enrolled in advanced mathematics courses nationwide were socialized in similar ways, using Campbell's differential socialization paradigm. Results uncovered a gender gap favoring boys. Self-imposed pressure and persistence had important direct effects on achievement. Self-concept had important direct…
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Jordt, Hannah; Eddy, Sarah L; Brazil, Riley; Lau, Ignatius; Mann, Chelsea; Brownell, Sara E; King, Katherine; Freeman, Scott
2017-01-01
Achievement gaps between underrepresented minority (URM) students and their white peers in college science, technology, engineering, and mathematics classrooms are persistent across many white-majority institutions of higher education. Attempts to reduce this phenomenon of underperformance through increasing classroom structure via active learning have been partially successful. In this study, we address the hypothesis that the achievement gap between white and URM students in an undergraduate biology course has a psychological and emotional component arising from stereotype threat. Specifically, we introduced a values affirmation exercise that counters stereotype threat by reinforcing a student's feelings of integrity and self-worth in three iterations of an intensive active-learning college biology course. On average, this exercise reduced the achievement gap between URM and white students who entered the course with the same incoming grade point average. This result suggests that achievement gaps resulting from the underperformance of URM students could be mitigated by providing students with a learning environment that removes psychological and emotional impediments of performance through short psychosocial interventions. © 2017 H. Jordt et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
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Closing achievement gaps with a utility-value intervention: Disentangling race and social class.
Harackiewicz, Judith M; Canning, Elizabeth A; Tibbetts, Yoi; Priniski, Stacy J; Hyde, Janet S
2016-11-01
Many college students abandon their goal of completing a degree in science, technology, engineering, or math (STEM) when confronted with challenging introductory-level science courses. In the U.S., this trend is more pronounced for underrepresented minority (URM) and first-generation (FG) students, and contributes to persisting racial and social-class achievement gaps in higher education. Previous intervention studies have focused exclusively on race or social class, but have not examined how the 2 may be confounded and interact. This research therefore investigates the independent and interactive effects of race and social class as moderators of an intervention designed to promote performance, measured by grade in the course. In a double-blind randomized experiment conducted over 4 semesters of an introductory biology course (N = 1,040), we tested the effectiveness of a utility-value intervention in which students wrote about the personal relevance of course material. The utility-value intervention was successful in reducing the achievement gap for FG-URM students by 61%: the performance gap for FG-URM students, relative to continuing generation (CG)-Majority students, was large in the control condition, .84 grade points (d = .98), and the treatment effect for FG-URM students was .51 grade points (d = 0.55). The UV intervention helped students from all groups find utility value in the course content, and mediation analyses showed that the process of writing about utility value was particularly powerful for FG-URM students. Results highlight the importance of intersectionality in examining the independent and interactive effects of race and social class when evaluating interventions to close achievement gaps and the mechanisms through which they may operate. (PsycINFO Database Record (c) 2016 APA, all rights reserved).
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Guo, Lan-Ping; Zhang, Yan; Zhu, Shou-Dong; Wang, Gui-Hua; Wang, Xiu; Zhang, Xiao-Bo; Chen, Mei-Lan; He, Ya-Li; Han, Bang-Xing; Chen, Nai-Fu; Huang, Lu-Qi
2014-04-01
This paper aims to summarize the achievements during the implementation process of good agricultural practice (GAP) in Chinese Materia Medica (CMM), and on basis of analyzing the existing problems of GAP, to propose further implementation of GAP in TCM growing. Since the launch of GAP in CMM growing ten years ago, it has acquired great achievements, including: (1) The promulgation of a series of measures for the administration of the GAP approval in the CMM growing; (2) The expanded planting area of CMM; (3) The increased awareness of standardized CMM growing among farmers and enterprises; (4) The establishment of GAP implementation bases for CMM growing; (5) The improvement of theory and methodology for CMM growing; (6) The development of a large group of experts and scholars in GAP approval for CMM production. The problems existing in the production include: (1) A deep understanding of GAP and its certification is still needed; (2) The distribution of the certification base is not reasonable; (3) The geo-economics effect and the backward farming practices are thought to be the bottlenecks in the standardization of CMM growing and the scale production of CMM; (4) Low comparative effectiveness limits the development of the GAP; (5) The base of breeding improved variety is blank; (6) The immature of the cultivation technique lead to the risk of production process; (7) The degradation of soil microbial and the continuous cropping obstacle restrict the sustainable development of the GAP base. To further promote the health and orderly GAP in the CMM growing, the authors propose: (1) To change the mode of production; (2) To establish a sound standard system so as to ensure quality products for fair prices; (3) To fully consider the geo-economic culture and vigorously promote the definite cultivating of traditional Chinese medicinal materials; (4) To strengthen the transformation and generalization of basic researches and achievements, in order to provide technical
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Whaley, Arthur L.; Noel, La Tonya
2012-01-01
Several theories suggest that African American culture facilitates academic achievement, but others suggest that identifying with Black culture contributes to the achievement gap by undermining the academic performance among youth. These opposing perspectives are labeled "cultural compatibility theories" and "cultural incompatibility theories,"…
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Cimpian, Joseph R.; Lubienski, Sarah T.; Timmer, Jennifer D.; Makowski, Martha B.; Miller, Emily K.
2016-01-01
Studies using data from the Early Childhood Longitudinal Study-Kindergarten Class of 1998-1999 (ECLS-K:1999) revealed gender gaps in mathematics achievement and teacher perceptions. However, recent evidence suggests that gender gaps have closed on state tests, raising the question of whether such gaps are absent in the ECLS-K:2011 cohort.…
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Shoraka, Mohammad; Arnold, Robert; Kim, Eun Sook; Salinitri, Geri; Kromrey, Jeffrey
2015-01-01
One of the most salient problems in education is the achievement gap. The researchers investigated the effects of parental education and parental occupations in science, technology, engineering, mathematics, or medical professions (STEMM) on the achievement gap in mathematics. Because students were nested within schools, two-level Hierarchical…
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Smith, James P.; Cage. Bob N.
2000-01-01
Studied the effects of 120 hours of chess instruction on the mathematics achievement of southern, rural, black secondary students. Analysis of covariance results show the treatment group (11 females, 9 males) scored significantly higher than the control group (10 females, 10 males) in mathematics achievement. Discusses results in terms of altering…
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Chowdhury, Chandra; Jahiruddin, Sheik; Datta, Ayan
2016-04-07
Phosphorene (Pn) is stabilized as a layered material like graphite, yet it possess a natural direct band gap (Eg = 2.0 eV). Interestingly, unlike graphene, Pn exhibits a much richer phase diagram which includes distorted forms like the stapler-clip (black Pn, α form) and chairlike (blue Pn, β form) structures. The existence of these phases is attributed to pseudo-Jahn-Teller (PJT) instability of planar hexagonal P6(6-) rings. In both cases, the condition for vibronic instability of the planar P6(6-) rings is satisfied. Doping with electron donors like tetrathiafulvalene and tetraamino-tetrathiafulvalene and electron acceptors like tetracyanoquinodimethane and tetracyanoethylene convert blue Pn into N-type and black Pn into efficient P-type semiconductors, respectively. Interestingly, pristine blue Pn, an indirect gap semiconductor, gets converted into a direct gap semiconductor on electron or hole doping. Because of comparatively smaller undulation in blue Pn (with respect to black Pn), the van der Waals interactions between the dopants and blue Pn is stronger. PJT distortions for two-dimensional phosphorus provides a unified understanding of structural features and chemical reactivity in its different phases.
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Patterson, Richard W.
2017-01-01
It is widely believed that the time children spend with parents significantly impacts human capital formation. If time varies significantly between black and white children, this may help explain the large racial gap in test scores and wages. In this study, I use data from the American Time Use Survey to examine the patterns in the time black and…
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Exploring racial differences in the obesity gender gap.
Seamans, Marissa J; Robinson, Whitney R; Thorpe, Roland J; Cole, Stephen R; LaVeist, Thomas A
2015-06-01
To investigate whether the gender gap in obesity prevalence is greater among U.S. blacks than whites in a study designed to account for racial differences in socioeconomic and environmental conditions. We estimated age-adjusted, race-stratified gender gaps in obesity (% female obese - % male obese, defined as body mass index ≥30 kg/m(2)) in the National Health Interview Survey 2003 and the Exploring Health Disparities in Integrated Communities-Southwest Baltimore 2003 study (EHDIC-SWB). EHDIC-SWB is a population-based survey of 1381 adults living in two urban, low-income, racially integrated census tracts with no race difference in income. In the National Health Interview Survey, the obesity gender gap was larger in blacks than whites as follows: 7.7 percentage points (ppts; 95% confidence interval (CI): 3.4-11.9) in blacks versus -1.5 ppts (95% CI: -2.8 to -0.2) in whites. In EHDIC-SWB, the gender gap was similarly large for blacks and whites as follows: 15.3 ppts (95% CI: 8.6-22.0) in blacks versus 14.0 ppts (95% CI: 7.1-20.9) in whites. In a racially integrated, low-income urban community, gender gaps in obesity prevalence were similar for blacks and whites. Copyright © 2015 Elsevier Inc. All rights reserved.
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Smeding, Annique; Darnon, Céline; Souchal, Carine; Toczek-Capelle, Marie-Christine; Butera, Fabrizio
2013-01-01
In spite of official intentions to reduce inequalities at University, students' socio-economic status (SES) is still a major determinant of academic success. The literature on the dual function of University suggests that University serves not only an educational function (i.e., to improve students' learning), but also a selection function (i.e., to compare people, and orient them towards different positions in society). Because current assessment practices focus on the selection more than on the educational function, their characteristics fit better with norms and values shared by dominant high-status groups and may favour high-SES students over low-SES students in terms of performances. A focus on the educational function (i.e., mastery goals), instead, may support low-SES students' achievement, but empirical evidence is currently lacking. The present research set out to provide such evidence and tested, in two field studies and a randomised field experiment, the hypothesis that focusing on University's educational function rather than on its selection function may reduce the SES achievement gap. Results showed that a focus on learning, mastery-oriented goals in the assessment process reduced the SES achievement gap at University. For the first time, empirical data support the idea that low-SES students can perform as well as high-SES students if they are led to understand assessment as part of the learning process, a way to reach mastery goals, rather than as a way to compare students to each other and select the best of them, resulting in performance goals. This research thus provides a theoretical framework to understand the differential effects of assessment on the achievement of high and low-SES students, and paves the way toward the implementation of novel, theory-driven interventions to reduce the SES-based achievement gap at University.
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Directory of Open Access Journals (Sweden)
Annique Smeding
Full Text Available In spite of official intentions to reduce inequalities at University, students' socio-economic status (SES is still a major determinant of academic success. The literature on the dual function of University suggests that University serves not only an educational function (i.e., to improve students' learning, but also a selection function (i.e., to compare people, and orient them towards different positions in society. Because current assessment practices focus on the selection more than on the educational function, their characteristics fit better with norms and values shared by dominant high-status groups and may favour high-SES students over low-SES students in terms of performances. A focus on the educational function (i.e., mastery goals, instead, may support low-SES students' achievement, but empirical evidence is currently lacking. The present research set out to provide such evidence and tested, in two field studies and a randomised field experiment, the hypothesis that focusing on University's educational function rather than on its selection function may reduce the SES achievement gap. Results showed that a focus on learning, mastery-oriented goals in the assessment process reduced the SES achievement gap at University. For the first time, empirical data support the idea that low-SES students can perform as well as high-SES students if they are led to understand assessment as part of the learning process, a way to reach mastery goals, rather than as a way to compare students to each other and select the best of them, resulting in performance goals. This research thus provides a theoretical framework to understand the differential effects of assessment on the achievement of high and low-SES students, and paves the way toward the implementation of novel, theory-driven interventions to reduce the SES-based achievement gap at University.
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Black phosphorus-based one-dimensional photonic crystals and microcavities.
Kriegel, Ilka; Toffanin, Stefano; Scotognella, Francesco
2016-11-10
The latest achievements in the fabrication of thin layers of black phosphorus (BP), toward the technological breakthrough of a phosphorene atomically thin layer, are paving the way for their use in electronics, optics, and optoelectronics. In this work, we have simulated the optical properties of one-dimensional photonic structures, i.e., photonic crystals and microcavities, in which few-layer BP is one of the components. The insertion of the 5-nm black phosphorous layers leads to a photonic band gap in the photonic crystals and a cavity mode in the microcavity that is interesting for light manipulation and emission enhancement.
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Robinson, Joseph Paul; Lubienski, Sarah Theule
2011-01-01
Using K-8 national longitudinal data, the authors investigate males' and females' achievement in math and reading, including when gender gaps first appear, whether the appearance of gaps depends on the metric used, and where on the achievement distribution gaps are most prevalent. Additionally, teachers' assessments of males and females are…
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Ding, Yi-min; Shi, Jun-jie; Zhang, Min; Zhu, Yao-hui; Wu, Meng; Wang, Hui; Cen, Yu-lang; Guo, Wen-hui; Pan, Shu-hang
2018-07-01
Within the framework of the spin-polarized density-functional theory, we have studied the electronic and magnetic properties of InSe/black-phosphorus (BP) heterostructure doped with 3d transition-metal (TM) atoms from Sc to Zn. The calculated binding energies show that TM-atom doping in the van der Waals (vdW) gap of InSe/BP heterostructure is energetically favorable. Our results indicate that magnetic moments are induced in the Sc-, Ti-, V-, Cr-, Mn- and Co-doped InSe/BP heterostructures due to the existence of non-bonding 3d electrons. The Ni-, Cu- and Zn-doped InSe/BP heterostructures still show nonmagnetic semiconductor characteristics. Furthermore, in the Fe-doped InSe/BP heterostructure, the half-metal property is found and a high spin polarization of 100% at the Fermi level is achieved. The Cr-doped InSe/BP has the largest magnetic moment of 4.9 μB. The Sc-, Ti-, V-, Cr- and Mn-doped InSe/BP heterostructures exhibit antiferromagnetic ground state. Moreover, the Fe- and Co-doped systems display a weak ferromagnetic and paramagnetic coupling, respectively. Our studies demonstrate that the TM doping in the vdW gap of InSe/BP heterostructure is an effective way to modify its electronic and magnetic properties.
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Karl Marx, Ludwig Wittgenstein, and Black Underachievement in the United States and United Kingdom
Tomlin, Carol; Wright, Cecile; Mocombe, Paul C.
2013-01-01
This article synthesizes Marxian conceptions of identity construction within capitalist relations of production with the Wittgensteinian notion of "language games" to offer a more appropriate relational framework within which scholars ought to understand the Black-White academic achievement gap in America, the United Kingdom, and…
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Daily online testing in large classes: boosting college performance while reducing achievement gaps.
Directory of Open Access Journals (Sweden)
James W Pennebaker
Full Text Available An in-class computer-based system, that included daily online testing, was introduced to two large university classes. We examined subsequent improvements in academic performance and reductions in the achievement gaps between lower- and upper-middle class students in academic performance. Students (N = 901 brought laptop computers to classes and took daily quizzes that provided immediate and personalized feedback. Student performance was compared with the same data for traditional classes taught previously by the same instructors (N = 935. Exam performance was approximately half a letter grade above previous semesters, based on comparisons of identical questions asked from earlier years. Students in the experimental classes performed better in other classes, both in the semester they took the course and in subsequent semester classes. The new system resulted in a 50% reduction in the achievement gap as measured by grades among students of different social classes. These findings suggest that frequent consequential quizzing should be used routinely in large lecture courses to improve performance in class and in other concurrent and subsequent courses.
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Low-mass black holes as the remnants of primordial black hole formation.
Greene, Jenny E
2012-01-01
Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.
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Garcia, Eugene E.; Lawton, Kerry; Diniz de Figueiredo, Eduardo H.
2010-01-01
This report reviews achievement gaps in both reading and math between ELL and non-ELL students in Arizona over the post-Proposition 203 period 2005-2009 and during the first year of implementation of the 4 hour ELD block, 2008-09. The study finds that Arizona has made little to no progress in closing the achievement gap between ELL and non-ELL…
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Do, D Phuong; Finch, Brian Karl; Basurto-Davila, Ricardo; Bird, Chloe; Escarce, Jose; Lurie, Nicole
2008-10-01
The persistence of the black health disadvantage has been a puzzling component of health in the United States in spite of general declines in rates of morbidity and mortality over the past century. Studies that have focused on well-established individual-level determinants of health such as socio-economic status and health behaviors have been unable to fully explain these disparities. Recent research has begun to focus on other factors such as racism, discrimination, and segregation. Variation in neighborhood context-socio-demographic composition, social aspects, and built environment-has been postulated as an additional explanation for racial disparities, but few attempts have been made to quantify its overall contribution to the black/white health gap. This analysis is an attempt to generate an estimate of place effects on explaining health disparities by utilizing data from the U.S. National Health Interview Survey (NHIS) (1989-1994), combined with a methodology for identifying residents of the same blocks both within and across NHIS survey cross-sections. Our results indicate that controlling for a single point-in-time measure of residential context results in a roughly 15-76% reduction of the black/white disparities in self-rated health that were previously unaccounted for by individual-level controls. The contribution of residential context toward explaining the black/white self-rated health gap varies by both age and gender such that contextual explanations of disparities decline with age and appear to be smaller among females.
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Robinson-Cimpian, Joseph P; Lubienski, Sarah Theule; Ganley, Colleen M; Copur-Gencturk, Yasemin
2014-04-01
A recent wave of research suggests that teachers overrate the performance of girls relative to boys and hold more positive attitudes toward girls' mathematics abilities. However, these prior estimates of teachers' supposed female bias are potentially misleading because these estimates (and teachers themselves) confound achievement with teachers' perceptions of behavior and effort. Using data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999 (ECLS-K), Study 1 demonstrates that teachers actually rate boys' mathematics proficiency higher than that of girls when conditioning on both teachers' ratings of behavior and approaches to learning as well as past and current test scores. In other words, on average girls are only perceived to be as mathematically competent as similarly achieving boys when the girls are also seen as working harder, behaving better, and being more eager to learn. Study 2 uses mediation analysis with an instrumental-variables approach, as well as a matching strategy, to explore the extent to which this conditional underrating of girls may explain the widening gender gap in mathematics in early elementary school. We find robust evidence suggesting that underrating girls' mathematics proficiency accounts for a substantial portion of the development of the mathematics achievement gap between similarly performing and behaving boys and girls in the early grades. PsycINFO Database Record (c) 2014 APA, all rights reserved.
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Voight, Adam; Hanson, Thomas; O'Malley, Meagan; Adekanye, Latifah
2015-12-01
This study used student and teacher survey data from over 400 middle schools in California to examine within-school racial disparities in students' experiences of school climate. It further examined the relationship between a school's racial climate gaps and achievement gaps and other school structures and norms that may help explain why some schools have larger or smaller racial disparities in student reports of climate than others. Multilevel regression results problematized the concept of a "school climate" by showing that, in an average middle school, Black and Hispanic students have less favorable experiences of safety, connectedness, relationships with adults, and opportunities for participation compared to White students. The results also show that certain racial school climate gaps vary in magnitude across middle schools, and in middle schools where these gaps are larger, the racial achievement gap is also larger. Finally, the socioeconomic status of students, student-teacher ratio, and geographic location help explain some cross-school variation in racial climate gaps. These findings have implications for how school climate in conceptualized, measured, and improved.
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Johnston, Daniel T; Furness, Robert W; Robbins, Alexandra M C; Tyler, Glen; Taggart, Mark A; Masden, Elizabeth A
2018-03-01
The black guillemot Cepphus grylle has been identified as a species likely to interact with marine renewable energy devices, specifically tidal turbines, with the potential to experience negative impacts. This likelihood is primarily based on the species being a diving seabird, and an inshore, benthic forager often associating with tidal streams. These behavioural properties may bring them into contact with turbine blades, or make them susceptible to alterations to tidal current speed, and/or changes in benthic habitat structure. We examine the knowledge currently available to assess the potential impacts of tidal stream turbines on black guillemot ecology, highlight knowledge gaps and make recommendations for future research. The key ecological aspects investigated include: foraging movements, diving behaviour, seasonal distribution, other sources of disturbance and colony recovery. Relating to foraging behaviour, between studies there is heterogeneity in black guillemot habitat use in relation to season, tide, diurnal cycles, and bathymetry. Currently, there is also little knowledge regarding the benthic habitats associated with foraging. With respect to diving behaviour, there is currently no available research regarding how black guillemots orientate and manoeuvre within the water column. Black guillemots are considered to be a non-migratory species, however little is known about their winter foraging range and habitat. The effect of human disturbance on breeding habitat and the metapopulation responses to potential mortalities are unknown. It is clear further understanding of black guillemot foraging habitat and behaviour is needed to provide renewable energy developers with the knowledge to sustainably locate tidal turbines and mitigate their impacts. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Teaching a lay theory before college narrows achievement gaps at scale.
Yeager, David S; Walton, Gregory M; Brady, Shannon T; Akcinar, Ezgi N; Paunesku, David; Keane, Laura; Kamentz, Donald; Ritter, Gretchen; Duckworth, Angela Lee; Urstein, Robert; Gomez, Eric M; Markus, Hazel Rose; Cohen, Geoffrey L; Dweck, Carol S
2016-06-14
Previous experiments have shown that college students benefit when they understand that challenges in the transition to college are common and improvable and, thus, that early struggles need not portend a permanent lack of belonging or potential. Could such an approach-called a lay theory intervention-be effective before college matriculation? Could this strategy reduce a portion of racial, ethnic, and socioeconomic achievement gaps for entire institutions? Three double-blind experiments tested this possibility. Ninety percent of first-year college students from three institutions were randomly assigned to complete single-session, online lay theory or control materials before matriculation (n > 9,500). The lay theory interventions raised first-year full-time college enrollment among students from socially and economically disadvantaged backgrounds exiting a high-performing charter high school network or entering a public flagship university (experiments 1 and 2) and, at a selective private university, raised disadvantaged students' cumulative first-year grade point average (experiment 3). These gains correspond to 31-40% reductions of the raw (unadjusted) institutional achievement gaps between students from disadvantaged and nondisadvantaged backgrounds at those institutions. Further, follow-up surveys suggest that the interventions improved disadvantaged students' overall college experiences, promoting use of student support services and the development of friendship networks and mentor relationships. This research therefore provides a basis for further tests of the generalizability of preparatory lay theories interventions and of their potential to reduce social inequality and improve other major life transitions.
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Jones, LaTonya S.
2011-01-01
Compared to other races, the college achievement gap is largest between Black men and women where females earn twice as many degrees as their male counterparts (National Center for Education Statistics, 2010, Status and trends in the education of racial and ethnic minorities). Many Black men attempt college and eventually drop out forfeiting their…
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Math Achievement Trajectories among Black Male Students in the Elementary- and Middle-School Years
Zilanawala, Afshin; Martin, Margary; Noguera, Pedro A.; Mincy, Ronald B.
2018-01-01
In this article, we analyze the variation in math achievement trajectories of Black male students to understand the different ways these students successfully or unsuccessfully navigate schools and the school characteristics that are associated with their trajectories. Using longitudinal student-level data from a large urban US city (n = 7,039),…
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Social and behavioral skills and the gender gap in early educational achievement.
Diprete, Thomas A; Jennings, Jennifer L
2012-01-01
Though many studies have suggested that social and behavioral skills play a central role in gender stratification processes, we know little about the extent to which these skills affect gender gaps in academic achievement. Analyzing data from the Early Child Longitudinal Study-Kindergarten Cohort, we demonstrate that social and behavioral skills have substantively important effects on academic outcomes from kindergarten through fifth grade. Gender differences in the acquisition of these skills, moreover, explain a considerable fraction of the gender gap in academic outcomes during early elementary school. Boys get roughly the same academic return to social and behavioral skills as their female peers, but girls begin school with more advanced social and behavioral skills and their skill advantage grows over time. While part of the effect may reflect an evaluation process that rewards students who better conform to school norms, our results imply that the acquisition of social and behavioral skills enhances learning as well. Our results call for a reconsideration of the family and school-level processes that produce gender gaps in social and behavioral skills and the advantages they confer for academic and later success. Copyright © 2011 Elsevier Inc. All rights reserved.
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Moving on Up: Urban to Suburban Translocation Experiences of High-Achieving Black American Students
Yu, Xiaoqi; Seeberg, Vilma; Malone, Larissa
2017-01-01
Minority suburbanization has been a fast growing demographic shift in the United States during the first decade of the 21st century. This article examines the tapestry of the suburbanization experience of a group of high-achieving Black American students and their families as told by them. Departing from the all too common, deficit orientation…
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Baker, Bruce D.; Farrie, Danielle; Sciarra, David G.
2016-01-01
Although there has been significant progress in the long term, achievement gaps among the nation's students persist.Many factors have contributed to the disparities in outcomes, and societal changes can explain progress, or lack thereof, over the past few decades.This is well documented in the 2010 Educational Testing Service (ETS) report…
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Igbinoba, Egheosa P.
Blacks are underrepresented amongst persons who earn college degrees in the United States and Black males attend and complete college at a lower rate than Black females (Toldson, Fry Brown, & Sutton, 2009). According to Toldson et al. (2009), this quandary may be attributed to Black males' apathy toward education in general, waning support and ideological challenges toward Pell Grants and affirmative action, cultural incompetency on the part of the 90% White, ethnic makeup of the U.S. teaching force, and the relatively high numbers of Black males who are held back in school. In spite of the dismal statistics regarding Black male academic achievement and matriculation, there are those Black males who do participate in postsecondary education. While many studies have highlighted reasons that Black males do not achieve success in attending and persisting through college, few have adopted the anti-deficit research framework suggested by Harper (2010), identifying reasons Black males do persist in higher education. Although science, technology, engineering, and mathematics careers are identified as those most imperative to the economic competitiveness of the United States, few studies have concentrated solely on engineering majors and fewer, if any, solely on Black male engineering majors at an historically Black college and university. The aim of this study was to address an apparent gap in the literature and invoke theories for recruitment, retention, and success of Black males in engineering degree programs by employing an anti-deficit achievement framework for research of students of color in science, technology, engineering, and mathematics. Data garnered from the study included insight into participants' definitions of success, precollege experiences, factors contributing to the persistence during undergraduate study, and perceptions of attending a historically Black college and university versus a primarily White institution.
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McGee, Ebony O.
2015-01-01
I introduce the construct of fragile and robust identities for the purpose of exploring the experiences that influenced the mathematical and racial identities of high-achieving Black college students in mathematics and engineering. These students maintained high levels of academic achievement in these fields while enduring marginalization,…
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Effects of Single-Sex and Coeducational Schooling on the Gender Gap in Educational Achievement
Gibb, Sheree J.; Fergusson, David M.; Horwood, L. John
2008-01-01
This study examined the effects of single-sex and coeducational schooling on the gender gap in educational achievement to age 25. Data were drawn from the Christchurch Health and Development Study, a longitudinal study of a birth cohort of 1265 individuals born in 1977 in Christchurch, New Zealand. After adjustment for a series of covariates…
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Moving to higher ground: Closing the high school science achievement gap
Mebane, Joyce Graham
The purpose of this study was to examine the perceptions of West High School constituents (students, parents, teachers, administrators, and guidance counselors) about the readiness and interest of African American students at West High School to take Advanced Placement (AP) and International Baccalaureate (IB) science courses as a strategy for closing the achievement gap. This case study utilized individual interviews and questionnaires for data collection. The participants were selected biology students and their parents, teachers, administrators, and guidance counselors at West High School. The results of the study indicated that just over half the students and teachers, most parents, and all guidance counselors thought African American students were prepared to take AP science courses. Only one of the three administrators thought the students were prepared to take AP science courses. Between one-half and two-thirds of the students, parents, teachers, and administrators thought students were interested in taking an AP science course. Only two of the guidance counselors thought there was interest among the African American students in taking AP science courses. The general consensus among the constituents about the readiness and interest of African American students at West High School to take IB science courses was that it is too early in the process to really make definitive statements. West is a prospective IB school and the program is new and not yet in place. Educators at the West High School community must find reasons to expect each student to succeed. Lower expectations often translate into lower academic demands and less rigor in courses. Lower academic demands and less rigor in courses translate into less than adequate performance by students. When teachers and administrators maintain high expectations, they encourage students to aim high rather than slide by with mediocre effort (Lumsden, 1997). As a result of the study, the following suggestions should
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Examining instruction, achievement, and equity with NAEP mathematics data.
Directory of Open Access Journals (Sweden)
Sarah Theule Lubienski
2006-06-01
Full Text Available The purpose of this article is two-fold. First, it reports on a study of the distribution of reform-oriented instructional practices among Black, White and Hispanic students, and the relationship between those practices and student achievement. The study identified many similarities in instruction across student groups, but there were some differences, such as Black and Hispanic students being assessed with multiple-choice tests significantly more often than were White students. Using hierarchical linear modeling, this study identified several significant positive—and no negative—relationships between reform-oriented practices and 4th-grade student achievement. Specifically, teacher emphasis on non-number mathematics strands, collaborative problem solving, and teacher knowledge of the NCTM Standards were positive predictors of achievement. An analysis of interaction effects indicated that the relationships between various instructional practices and achievement were roughly similar for White, Black and Hispanic students. The second purpose of this article is to make comparisons with another study that used the same NAEP data, but drew very different conclusions about the potential for particular instructional practices to alleviate inequities. A study published in EPAA by Wenglinsky (2004 concluded that school personnel can eliminate race-related gaps within their schools by changing their instructional practices. Similarities and differences between these two studies are discussed to illuminate how a researcher's framing, methods, and interpretations can heavily influence a study's conclusions. Ultimately, this article argues that the primary conclusion of Wenglinsky's study is unwarranted. Keywords: equity, hierarchical linear modeling; mathematics achievement; mathematics instruction; NAEP.
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Berger, Dan; Wild, Charles
2017-01-01
Teaching standards within the UK's higher education sector are under unprecedented scrutiny not only in terms of perceived "highly variable" standards of teaching but also in relation to the clear attainment gap between black, Asian and minority ethnic (BAME) students and their white counterparts. Gentle taps at the door to the higher…
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Directory of Open Access Journals (Sweden)
Lei Zhou
2017-02-01
Full Text Available Although our society is in rapid development, the psychological problems among in-school university students are increasingly obvious. According to this problem, this thesis applied the Psychological Gap Scale made by Caixia Ma with EPQ and AMS, and made random questionnaire survey among 400 students in a comprehensive university. The survey found out that the average scores of all psychological gap dimensions exceeded the critical value 3, showing most students in that university have psychological gap. Their personality stability, introversion and extroversion are all above the national norm level while their stubbornness is lower than it. Besides, the students’ motivation in pursuing success is stronger than their motivation in avoiding failure. In the last part, this thesis reached the conclusion that personality leaves a great impact in the students’ psychology through regression analysis model and study of the quantitative relations among personality, achievement and psychological gap.
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Annamma, Subini; Morrison, Deb; Jackson, Darrell
2014-01-01
The focus on the achievement gap has overshadowed ways in which school systems constrain student achievement through trends of racial disproportionality in areas such as school discipline, special education assignment, and juvenile justice. Using Critical Race Theory, we reframe these racial disparities as issues of institutionalized racism.…
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Casavantes, Edward Joseph
Two sets of data from the U.S. Commission on Civil Rights' Mexican American Education Study were selected for analysis in the areas of (1) comparative reading achievement rates of Mexican Americans and black students; and (2) differential in-grade retention rates of Anglo, Mexican American, and black students. Two separate issues were examined.…
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Closing the N-use efficiency gap to achieve food and environmental security.
Cui, Zhenling; Wang, Guiliang; Yue, Shanchao; Wu, Liang; Zhang, Weifeng; Zhang, Fusuo; Chen, Xinping
2014-05-20
To achieve food and environmental security, closing the gap between actual and attainable N-use efficiency should be as important as closing yield gaps. Using a meta-analysis of 205 published studies from 317 study sites, including 1332 observations from rice, wheat, and maize system in China, reactive N (Nr) losses, and total N2O emissions from N fertilization both increased exponentially with increasing N application rate. On the basis of the N loss response curves from the literature meta-analysis, the direct N2O emission, NH3 volatilization, N leaching, and N runoff, and total N2O emission (direct + indirect) were calculated using information from the survey of farmers. The PFP-N (kilogram of harvested product per kilogram of N applied (kg (kg of N)(-1))) for 6259 farmers were relative low with only 37, 23, and 32 kg (kg of N)(-1) for rice, wheat, and maize systems, respectively. In comparison, the PFP-N for highest yield and PFP-N group (refers to fields where the PFP-N was within the 80-100th percentile among those fields that achieved yields within the 80-100th percentile) averaged 62, 42, and 53 kg (kg of N)(-1) for rice, wheat, and maize systems, respectively. The corresponding grain yield would increase by 1.6-2.3 Mg ha(-1), while the N application rate would be reduced by 56-100 kg of N ha(-1) from average farmer field to highest yield and PFP-N group. In return, the Nr loss intensity (4-11 kg of N (Mg of grain)(-1)) and total N2O emission intensity (0.15-0.29 kg of N (Mg of grain)(-1)) would both be reduced significantly as compared to current agricultural practices. In many circumstances, closing the PFP-N gap in intensive cropping systems is compatible with increased crop productivity and reductions in both Nr losses and total N2O emissions.
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Jordt, Hannah; Eddy, Sarah L.; Brazil, Riley; Lau, Ignatius; Mann, Chelsea; Brownell, Sara E.; King, Katherine; Freeman, Scott
2017-01-01
Achievement gaps between underrepresented minority (URM) students and their white peers in college science, technology, engineering, and mathematics classrooms are persistent across many white-majority institutions of higher education. Attempts to reduce this phenomenon of underperformance through increasing classroom structure via active learning…
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Shafiq, M. Najeeb
2013-01-01
Using quantile regression analyses, this study examines gender gaps in mathematics, science, and reading in Azerbaijan, Indonesia, Jordan, the Kyrgyz Republic, Qatar, Tunisia, and Turkey among 15-year-old students. The analyses show that girls in Azerbaijan achieve as well as boys in mathematics and science and overachieve in reading. In Jordan,…
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Schwery, Denise; Hulac, David; Schweinle, Amy
2016-01-01
This literature review provides school psychologists with an understanding of the important issues related to the gender gap in mathematics achievement. The extant literature suggests that girls tend to receive lower scores than boys on standardized math tests, but in general these differences tend to be small. However, girls have better classroom…
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Photonic devices based on black phosphorus and related hybrid materials
International Nuclear Information System (INIS)
Vitiello, M.S.; Viti, L.
2016-01-01
Artificial semiconductor heterostructures played a pivotal role in modern electronic and photonic technologies, providing a highly effective means for the manipulation and control of carriers, from the visible to the far-infrared, leading to the development of highly efficient devices like sources, detectors and modulators. The discovery of graphene and the related fascinating capabilities have triggered an unprecedented interest in devices based on inorganic two-dimensional (2D) materials. Amongst them, black phosphorus (BP) recently showed an extraordinary potential in a variety of applications across micro-electronics and photonics. With an energy gap between the gapless graphene and the larger gap transition metal dichalcogenides, BP can form the basis for a new generation of high-performance photonic devices that could be specifically engineered to comply with different applications, like transparent saturable absorbers, fast photocounductive switches and low noise photodetectors, exploiting its peculiar electrical, thermal and optical anisotropy. This paper will review the latest achievements in black-phosphorus–based THz photonics and discuss future perspectives of this rapidly developing research field.
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Inattention and hyperactivity and the achievement gap among urban minority youth.
Basch, Charles E
2011-10-01
To outline the prevalence and disparities of inattention and hyperactivity among school-aged urban minority youth, causal pathways through which inattention and hyperactivity adversely affects academic achievement, and proven or promising approaches for schools to address these problems. Literature review. Approximately 4.6 million (8.4%) of American youth aged 6-17 have received a diagnosis of attention deficit/hyperactivity disorder (ADHD), and almost two thirds of these youth are reportedly under treatment with prescription medications. Urban minority youth are not only more likely to be affected but also less likely to receive accurate diagnosis and treatment. Causal pathways through which ADHD may affect academic achievement include sensory perceptions, cognition, school connectedness, absenteeism, and dropping out. In one study, youth with diagnosed ADHD were 2.7 times as likely to drop out (10.0% vs. 22.9%). A similar odds ratio for not graduating from high school was found in another prospective study, with an 8-year follow-up period (odds ratio = 2.4). There are many children who are below the clinical diagnostic threshold for ADHD but who exhibit signs and symptoms that interfere with learning. Evidence-based programs emphasizing functional academic and social outcomes are available. Inattention and hyperactivity are highly and disproportionately prevalent among school-aged urban minority youth, have a negative impact on academic achievement through their effects on sensory perceptions, cognition, school connectedness, absenteeism, and dropping out, and effective practices are available for schools to address these problems. This prevalent and complex syndrome has very powerful effects on academic achievement and educational attainment, and should be a high priority in efforts to help close the achievement gap. © 2011, American School Health Association.
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Qian, Xiaoyu; Nandakumar, Ratna; Glutting, Joseoph; Ford, Danielle; Fifield, Steve
2017-01-01
In this study, we investigated gender and minority achievement gaps on 8th-grade science items employing a multilevel item response methodology. Both gaps were wider on physics and earth science items than on biology and chemistry items. Larger gender gaps were found on items with specific topics favoring male students than other items, for…
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Few-layer black phosphorus nanoparticles.
Sofer, Zdenek; Bouša, Daniel; Luxa, Jan; Mazanek, Vlastimil; Pumera, Martin
2016-01-28
Herein, black phosphorus quantum dots and nanoparticles of a few layer thickness were prepared and characterized using STEM, AFM, dynamic light scattering, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and photoluminescence. Impact electrochemistry of the induvidual black phosphorus nanoparticles allows their size determination. The centrifugation of colloidal black phosphorus nanoparticles allowed separation of quantum dots with sizes up to 15 nm. These black phosphorus nanoparticles exhibit a large band gap and are expected to find a wide range of applications from semiconductors to biomolecule tags. The use of black phosphorus nanoparticles for vapour sensing was successfully demonstrated.
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Hope, Elan C.; Chavous, Tabbye M.; Jagers, Robert J.; Sellers, Robert M.
2013-01-01
Using a person-oriented approach, we explored patterns of self-esteem and achievement among 324 Black college students across the freshman college year and identified four academic identification profiles. Multivariate analyses revealed profile differences in academic and psychological outcomes at beginning and end of freshman year (academic…
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Reducing the gender achievement gap in college science: a classroom study of values affirmation.
Miyake, Akira; Kost-Smith, Lauren E; Finkelstein, Noah D; Pollock, Steven J; Cohen, Geoffrey L; Ito, Tiffany A
2010-11-26
In many science, technology, engineering, and mathematics disciplines, women are outperformed by men in test scores, jeopardizing their success in science-oriented courses and careers. The current study tested the effectiveness of a psychological intervention, called values affirmation, in reducing the gender achievement gap in a college-level introductory physics class. In this randomized double-blind study, 399 students either wrote about their most important values or not, twice at the beginning of the 15-week course. Values affirmation reduced the male-female performance and learning difference substantially and elevated women's modal grades from the C to B range. Benefits were strongest for women who tended to endorse the stereotype that men do better than women in physics. A brief psychological intervention may be a promising way to address the gender gap in science performance and learning.
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Lynch, Robert G.; Oakford, Patrick
2014-01-01
Our nation is currently experiencing growing levels of income and wealth inequality, which are contributing to longstanding racial and ethnic gaps in education outcomes and other areas. This report quantifies the economic benefits of closing one of the most harmful racial and ethnic gaps: the educational achievement gap that exists between black…
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Being Black and Brown in the 21st Century
Directory of Open Access Journals (Sweden)
Pierre W. Orelus
2012-11-01
Full Text Available Depending on one’s level of understanding and awareness about the plight of Black and Brown people, one might argue that they are better off today than they were 50 years ago or so, especially when one remembers the Jim Crow era during which Black and Brown people were ruthlessly brutalized, particularly by White supremacist groups such as the Klu Klux Kan. However, if one critically analyzed the achievement gap between students of color and their White counterparts, the decline in incomes, and other forms of educational and socioeconomic inequality that Black and Brown people, particularly poor students of color, have been experiencing for the last several decades or so, one would realize that substantially nothing has changed for them. In light of this view, this article explores the educational and socioeconomic conditions of People of Color, including those of linguistically and culturally diverse students. Specifically, it examines the ways and the degree to which lack of resources combined with institutional racism and the legacy of slavery continue to limit the life chances of Black and Brown people in the 21st century. The author ends this article making recommendations to counter inequality in schools and society at large that Black and Brown people have been facing.
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McCombs, Barbara L.
2000-01-01
Reviews the College Board's report, "Reaching the Top," which addresses educational underrepresentation of high-achieving minority students, examining how social sciences, psychology, and education research contribute to an understanding of the feasibility of the report's recommendations and noting implications of these recommendations…
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Gender Gaps in Achievement and Participation in Multiple Introductory Biology Classrooms
Brownell, Sara E.; Wenderoth, Mary Pat
2014-01-01
Although gender gaps have been a major concern in male-dominated science, technology, engineering, and mathematics disciplines such as physics and engineering, the numerical dominance of female students in biology has supported the assumption that gender disparities do not exist at the undergraduate level in life sciences. Using data from 23 large introductory biology classes for majors, we examine two measures of gender disparity in biology: academic achievement and participation in whole-class discussions. We found that females consistently underperform on exams compared with males with similar overall college grade point averages. In addition, although females on average represent 60% of the students in these courses, their voices make up less than 40% of those heard responding to instructor-posed questions to the class, one of the most common ways of engaging students in large lectures. Based on these data, we propose that, despite numerical dominance of females, gender disparities remain an issue in introductory biology classrooms. For student retention and achievement in biology to be truly merit based, we need to develop strategies to equalize the opportunities for students of different genders to practice the skills they need to excel. PMID:25185231
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Saw, Guan Kung
2016-01-01
Educational inequality is a highly debated yet empirically understudied topic in Malaysia. This paper examines the patterns and trends of academic achievement gaps by student social groups in Malaysia, drawing upon nationally representative data for the most recent four cohorts (1999, 2003, 2007, and 2011) of eighth-grade Malaysian students from…
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International Nuclear Information System (INIS)
Hod, Shahar
2015-01-01
It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ gap /τ emission = O(1), where τ gap is the average time gap between the emissions of successive Hawking quanta and τ emission is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)
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Energy Technology Data Exchange (ETDEWEB)
Hod, Shahar [The Ruppin Academic Center, Emek Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)
2015-07-15
It is shown that rapidly-rotating Kerr black holes are characterized by the dimensionless ratio τ{sub gap}/τ{sub emission} = O(1), where τ{sub gap} is the average time gap between the emissions of successive Hawking quanta and τ{sub emission} is the characteristic timescale required for an individual Hawking quantum to be emitted from the black hole. This relation implies that the Hawking cascade from rapidly-rotating black holes has an almost continuous character. Our results correct some inaccurate claims that recently appeared in the literature regarding the nature of the Hawking black-hole evaporation process. (orig.)
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Herman, Melissa R.
This paper describes the achievement patterns of a sample of 1,492 multiracial high school students and examines how their achievement fits into existing theoretical models that explain monoracial differences in achievement. These theoretical models include status attainment, parenting style, oppositional culture, and educational attitudes. The…
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Loop quantum gravity and black hole entropy quantization
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Using the spin networks and the asymptotic quasinormal mode frequencies of black holes given by loop quantum gravity,the minimum horizon area gap is obtained.Then the quantum area spectrum of black holes is derived and the black hole entropy is a realized quantization.The results show that the black hole entropy given by loop quantum gravity is in full accord with the Bekenstein-Hawking entropy with a suitable Immirzi.
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Mulugeta, Betselot; Williamson, Susan; Monks, Rob; Hack, Thomas; Beaver, Kinta
2017-08-01
Little is known about black African (BA) and black African-Caribbean (BAC) men's views towards cancer; yet culture and acculturation can contribute to the way in which people understand, explain and develop their attitudes towards cancer. Hence, cancer prevention and early detection strategies may not be sensitive to United Kingdom (UK)-based black men's views, affecting their awareness of risk factors and early detection services. This study explored the views of UK-based BA and BAC men towards cancer. In collaboration with black community organisations based in four major cities in the UK, 25 participants were recruited using convenience and theoretical sampling methods. Data were collected using 33 semi-structured interviews, and analysed using grounded theory analytic procedures. One core category (cancer through black eyes) and seven sub-categories emerged; 'cultural views', 'religious beliefs', 'avoiding Babylon', 'alienation', 'suspicious mind', 'advertisements and information influence very little', and 'gap in service provision (bridging the gap)'. Participants' views towards cancer were linked to socially constructed perspectives, linked with cultural and religious beliefs, and shaped by what being a black male means in society. Risk factors such as smoking and obesity had different meanings and symbolisation through black eyes. There were macro- and micro-level similarities and differences between BA and BAC men. Cancer services and related public-health campaigns aimed at black men need to understand cancer through black eyes. Public health campaigns based solely on the clinical meaning of cancer are incongruent with black men's understandings of cancer, and therefore ineffective at reducing health inequality. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Cobbs, Joyce Bernice
2014-01-01
The literature on minority student achievement indicates that Black students are underrepresented in advanced mathematics courses. Advanced mathematics courses offer students the opportunity to engage with challenging curricula, experience rigorous instruction, and interact with quality teachers. The middle school years are particularly…
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National Center for Education Statistics, 2011
2011-01-01
This report provides a detailed portrait of Hispanic and White academic achievement gaps and how students' performance has changed over time at both the national and state levels. The report presents achievement gaps using reading and mathematics assessment data from the National Assessment of Educational Progress (NAEP) for the 4th- and 8th-grade…
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Goddard, Roger D.; Skrla, Linda; Salloum, Serena J.
2017-01-01
Previous research demonstrates that collective efficacy positively predicts students' academic achievement (e.g., Bandura, 1993; Goddard et al., 2000). However, unaddressed by the current literature is whether collective efficacy also works to reduce inequity by closing achievement gaps. To learn about the operation of collective efficacy, we…
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Trajectories of Achievement within Race/Ethnicity: "Catching Up" in Achievement across Time
Davis-Kean, Pamela E.; Jager, Justin
2014-01-01
The achievement gap has long been the focus of educational research, policy, and intervention. The authors took a new approach to examining the achievement gap by examining achievement trajectories within each racial group. To identify these trajectories they used the Early Childhood Longitudinal Study-Kindergarten Cohort, which is a nationally…
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Employment gains and wage declines: the erosion of black women's relative wages since 1980.
Pettit, Becky; Ewert, Stephanie
2009-08-01
Public policy initiatives in the 1950s and 1960s, including Affirmative Action and Equal Employment Opportunity law, helped mitigate explicit discrimination in pay, and the expansion of higher education and training programs have advanced the employment fortunes of many American women. By the early 1980s, some scholars proclaimed near equity in pay between black and white women, particularly among young and highly skilled workers. More recent policy initiatives and labor market conditions have been arguably less progressive for black women's employment and earnings: through the 1980s, 1990s, and the first half of the 2000s, the wage gap between black and white women widened considerably. Using data from the Current Population Survey Merged Outgoing Rotation Group (CPS-MORG), this article documents the racial wage gap among women in the United States from 1979 to 2005. We investigate how demographic and labor market conditions influence employment and wage inequality among black and white women over the period. Although shifts in labor supply influence the magnitude of the black-white wage gap among women, structural disadvantages faced by black women help explain the growth in the racial wage gap.
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Tian, Bin; Tian, Bining; Smith, Bethany; Scott, M C; Hua, Ruinian; Lei, Qin; Tian, Yue
2018-04-11
Solar-driven water splitting using powdered catalysts is considered as the most economical means for hydrogen generation. However, four-electron-driven oxidation half-reaction showing slow kinetics, accompanying with insufficient light absorption and rapid carrier combination in photocatalysts leads to low solar-to-hydrogen energy conversion efficiency. Here, we report amorphous cobalt phosphide (Co-P)-supported black phosphorus nanosheets employed as photocatalysts can simultaneously address these issues. The nanosheets exhibit robust hydrogen evolution from pure water (pH = 6.8) without bias and hole scavengers, achieving an apparent quantum efficiency of 42.55% at 430 nm and energy conversion efficiency of over 5.4% at 353 K. This photocatalytic activity is attributed to extremely efficient utilization of solar energy (~75% of solar energy) by black phosphorus nanosheets and high-carrier separation efficiency by amorphous Co-P. The hybrid material design realizes efficient solar-to-chemical energy conversion in suspension, demonstrating the potential of black phosphorus-based materials as catalysts for solar hydrogen production.
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Basch, Charles E
2011-10-01
This article provides an introduction to the October 2011 special issue of the Journal of School Health on "Healthier Students Are Better Learners." Literature was reviewed and synthesized to identify health problems affecting school-aged youth that are highly prevalent, disproportionately affect urban minority youth, directly and indirectly causally affect academic achievement, and can be feasibly and effectively addressed through school health programs and services. Based on these criteria, 7 educationally relevant health disparities were selected as strategic priorities to help close the achievement gap: (1) vision, (2) asthma, (3) teen pregnancy, (4) aggression and violence, (5) physical activity, (6) breakfast, and (7) inattention and hyperactivity. Research clearly shows that these health problems influence students' motivation and ability to learn. Disparities among urban minority youth are outlined, along with the causal pathways through which each adversely affects academic achievement, including sensory perceptions, cognition, school connectedness, absenteeism, and dropping out. Evidence-based approaches that schools can implement to address these problems are presented. These health problems and the causal pathways they influence have interactive and a synergistic effect, which is why they must be addressed collectively using a coordinated approach. No matter how well teachers are prepared to teach, no matter what accountability measures are put in place, no matter what governing structures are established for schools, educational progress will be profoundly limited if students are not motivated and able to learn. Particular health problems play a major role in limiting the motivation and ability to learn of urban minority youth. This is why reducing these disparities through a coordinated approach warrants validation as a cohesive school improvement initiative to close the achievement gap. Local, state, and national policies for implementing this
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Energy Technology Data Exchange (ETDEWEB)
Lin, L. C.-C.; Pu, Hung-Yi; Hirotani, Kouichi; Matsushita, Satoki; Inoue, Makoto [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Kong, Albert K. H; Chang, Hsiang-Kuang [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Tam, Pak-Hin T., E-mail: lupin@asiaa.sinica.edu.tw, E-mail: hpu@perimeterinstitute.ca, E-mail: hirotani@tiara.sinica.edu.tw [School of Physics and Astronomy, Sun Yat-Sen University, Zhuhai 519082 (China)
2017-08-10
We search for the gamma-ray counterparts of stellar-mass black holes using the long-term Fermi archive to investigate the electrostatic acceleration of electrons and positrons in the vicinity of the event horizon. We achieve this by applying the pulsar outer-gap model to their magnetospheres. When a black hole transient (BHT) is in a low-hard or quiescent state, the radiatively inefficient accretion flow cannot emit enough MeV photons that are required to sustain the force-free magnetosphere in the polar funnel via two-photon collisions. In this charge-starved gap region, an electric field arises along the magnetic field lines to accelerate electrons and positrons into ultra-relativistic energies. These relativistic leptons emit copious Gamma-rays via the curvature and inverse-Compton (IC) processes. It is found that these gamma-ray emissions exhibit a flaring activity when the plasma accretion rate typically stays between 0.01% and 0.005% of the Eddington value for rapidly rotating, stellar-mass black holes. By analyzing the detection limit determined from archival Fermi /Large Area Telescope data, we find that the 7-year averaged duty cycle of such flaring activities should be less than 5% and 10% for XTE J1118+480 and 1A 0620-00, respectively, and that the detection limit is comparable to the theoretical prediction for V404 Cyg. It is predicted that the gap emission can be discriminated from the jet emission if we investigate the high-energy spectral behavior or observe nearby BHTs during deep quiescence simultaneously in infrared wavelength and very-high energies.
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Employment Gains and Wage Declines: The Erosion of Black Women’s Relative Wages Since 1980
PETTIT, BECKY; EWERT, STEPHANIE
2009-01-01
Public policy initiatives in the 1950s and 1960s, including Affirmative Action and Equal Employment Opportunity law, helped mitigate explicit discrimination in pay, and the expansion of higher education and training programs have advanced the employment fortunes of many American women. By the early 1980s, some scholars proclaimed near equity in pay between black and white women, particularly among young and highly skilled workers. More recent policy initiatives and labor market conditions have been arguably less progressive for black women’s employment and earnings: through the 1980s, 1990s, and the first half of the 2000s, the wage gap between black and white women widened considerably. Using data from the Current Population Survey Merged Outgoing Rotation Group (CPS-MORG), this article documents the racial wage gap among women in the United States from 1979 to 2005. We investigate how demographic and labor market conditions influence employment and wage inequality among black and white women over the period. Although shifts in labor supply influence the magnitude of the black-white wage gap among women, structural disadvantages faced by black women help explain the growth in the racial wage gap. PMID:19771940
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Basch, Charles E
2011-10-01
To discuss implications for educational policy and practice relevant to closing the achievement gap based on the literature review and synthesis presented in 7 articles of the October 2011 special issue of the Journal of School Health. Implications for closing the achievement gap are drawn from analyses of current literature. During the past several decades, school reform efforts to close the achievement gap have focused on various strategies, yielding very limited progress. Educationally relevant health disparities influence students' motivation and ability to learn, but reducing these disparities has been largely overlooked as an element of an overall strategy for closing the achievement gap. If these health problems are not addressed, the educational benefits of other school reform efforts will be jeopardized. Healthier students are better learners. School health programs and services that are evidence based, strategically planned to influence academic achievement, and effectively coordinated warrant validation as a cohesive school improvement initiative for closing the achievement gap. National, state, and local responsibilities for supporting school health are outlined, including shared strategies; leadership from the U.S. Department of Education; policy development; guidance, technical assistance, and professional development; accountability and data and software systems; and a research agenda. To date, the U.S. Department of Education has not provided leadership for integrating evidence-based, strategically planned, and effectively coordinated school health programs and services into the fundamental mission of schools. Now is an opportune time for change. © 2011, American School Health Association.
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Frisvold, David; Golberstein, Ezra
2013-12-01
This study assesses the effect of black-white differences in school quality on black-white differences in health in later life resulting from the racial convergence in school quality for cohorts born between 1910 and 1950 in southern states with segregated schools. Using data from the 1984-2007 National Health Interview Surveys linked to race-specific data on school quality, we find that reductions in the black-white gap in school quality led to modest reductions in the black-white gap in disability.
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Sperling, Rick; Zwahr-Castro, Jennifer; Cruz, Felicia; Montalvo, Jason
2017-01-01
Previous research has shown that people often engage in cultural-deficit thinking when reasoning about racial/ethnic achievement gaps. However, it is unclear whether culture-blaming explanations are best thought of as group-level internal attributions, expressions of prejudice against a lower status group, or self-serving bias. In this study,…
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The Effect of Black Peers on Black Test Scores
Armor, David J.; Duck, Stephanie
2007-01-01
Recent studies have used increasingly complex methodologies to estimate the effect of peer characteristics--race, poverty, and ability--on student achievement. A paper by Hanushek, Kain, and Rivkin using Texas state testing data has received particularly wide attention because it found a large negative effect of school percent black on black math…
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Bowleg, Lisa; English, Devin; Del Rio-Gonzalez, Ana Maria; Burkholder, Gary J; Teti, Michelle; Tschann, Jeanne M
2016-04-01
Although extensive research documents that Black people in the U.S. frequently experience social discrimination, most of this research aggregates these experiences primarily or exclusively by race. Consequently, empirical gaps exist about the psychosocial costs and benefits of Black men's experiences at the intersection of race and gender. Informed by intersectionality, a theoretical framework that highlights how multiple social identities intersect to reflect interlocking social-structural inequality, this study addresses these gaps with the qualitative development and quantitative test of the Black Men's Experiences Scale (BMES). The BMES assesses Black men's negative experiences with overt discrimination and microaggressions, as well their positive evaluations of what it means to be Black men. First, we conducted focus groups and individual interviews with Black men to develop the BMES. Next, we tested the BMES with 578 predominantly low-income urban Black men between the ages of 18 and 44. Exploratory factor analysis suggested a 12-item, 3-factor solution that explained 63.7% of the variance. We labeled the subscales: Overt Discrimination, Microaggressions, and Positives: Black Men . Confirmatory factor analysis supported the three-factor solution. As hypothesized, the BMES's subscales correlated with measures of racial discrimination, depression, resilience, and social class at the neighborhood-level. Preliminary evidence suggests that the BMES is a reliable and valid measure of Black men's experiences at the intersection of race and gender.
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Black hole entropy, curved space and monsters
International Nuclear Information System (INIS)
Hsu, Stephen D.H.; Reeb, David
2008-01-01
We investigate the microscopic origin of black hole entropy, in particular the gap between the maximum entropy of ordinary matter and that of black holes. Using curved space, we construct configurations with entropy greater than the area A of a black hole of equal mass. These configurations have pathological properties and we refer to them as monsters. When monsters are excluded we recover the entropy bound on ordinary matter S 3/4 . This bound implies that essentially all of the microstates of a semiclassical black hole are associated with the growth of a slightly smaller black hole which absorbs some additional energy. Our results suggest that the area entropy of black holes is the logarithm of the number of distinct ways in which one can form the black hole from ordinary matter and smaller black holes, but only after the exclusion of monster states
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Gender gaps in achievement and participation in multiple introductory biology classrooms.
Eddy, Sarah L; Brownell, Sara E; Wenderoth, Mary Pat
2014-01-01
Although gender gaps have been a major concern in male-dominated science, technology, engineering, and mathematics disciplines such as physics and engineering, the numerical dominance of female students in biology has supported the assumption that gender disparities do not exist at the undergraduate level in life sciences. Using data from 23 large introductory biology classes for majors, we examine two measures of gender disparity in biology: academic achievement and participation in whole-class discussions. We found that females consistently underperform on exams compared with males with similar overall college grade point averages. In addition, although females on average represent 60% of the students in these courses, their voices make up less than 40% of those heard responding to instructor-posed questions to the class, one of the most common ways of engaging students in large lectures. Based on these data, we propose that, despite numerical dominance of females, gender disparities remain an issue in introductory biology classrooms. For student retention and achievement in biology to be truly merit based, we need to develop strategies to equalize the opportunities for students of different genders to practice the skills they need to excel. © 2014 S. L. Eddy et al. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
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DEFF Research Database (Denmark)
Beermann, Jonas; Eriksen, René L.; Stær, Tobias Holmgaard
2014-01-01
Plasmonic black surfaces formed by two-dimensional arrays of ultra-sharp convex metal grooves, in which the incident radiation is converted into gap surface plasmon polaritons (GSPPs) and subsequently absorbed (via adiabatic nanofocusing), are fabricated and investigated experimentally for gold......%, averaged over the investigated wavelength range of 400-985 nm. The highest averaged absorption level (similar to 97%) is achieved with 250-nm-period arrays in palladium that also has the highest melting temperature(similar to 15526 degrees C), promising thereby potential applications for broadband...
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Home media and children's achievement and behavior.
Hofferth, Sandra L
2010-01-01
This study provides a national picture of the time American 6- to 12-year-olds spent playing video games, using the computer, and watching TV at home in 1997 and 2003, and the association of early use with their achievement and behavior as adolescents. Girls benefited from computer use more than boys, and Black children benefited more than White children. Greater computer use in middle childhood was associated with increased achievement for White and Black girls, and for Black but not White boys. Increased video game play was associated with an improved ability to solve applied problems for Black girls but lower verbal achievement for all girls. For boys, increased video game play was linked to increased aggressive behavior problems. © 2010 The Author. Child Development © 2010 Society for Research in Child Development, Inc.
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Jacobowitz, Tina
Science career preferences of junior high school-aged students, while not stable predictors of ultimate career choice, do serve to direct and maintain individuals along the paths to careers in science. In this study, factors relevant to science career preferences of black eighth grade students were investigated. This issue is of particular import to blacks since they are severely underrepresented in the scientific fields. The sample consisted of 113 males and 148 females in an inner city junior high school. The Science Career Preference Scale, the Peabody Picture Vocabulary Test, and the Self-Concept of Ability Scale (Form B-Science) were administered. Mathematics and science grades were obtained from class rating sheets. Treatment of the data involved multiple regression analysis according to a hierarchical model. Results showed that of all the independent variables, sex was the strongest predictor of science career preferences, accounting for 25% of the criterion variance. The findings suggest that early adolescent science career preferences are related more to interests that are consonant with sex-role considerations than realistic assessment of mathematics or science achievement.
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Grant, Gloria W.
The purpose of this study was to examine the effect of text materials with relevant language, illustrations, and content upon the reading achievement and reading preference (attitude) of black primary and intermediate grade inner-city students. The subjects for the study were 330 black students enrolled in three schools in a large urban area. A…
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Dey, Judy Goldberg; Hill, Catherine
2007-01-01
Women have made remarkable gains in education during the past three decades, yet these achievements have resulted in only modest improvements in pay equity. The gender pay gap has become a fixture of the U.S. workplace and is so ubiquitous that many simply view it as normal. "Behind the Pay Gap" examines the gender pay gap for college graduates.…
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Cobbs, Joyce Bernice
2015-01-01
The literature on minority student achievement indicates that Black students are underrepresented in advanced mathematics courses. Advanced mathematics courses offer students the opportunity to engage with challenging curricula, experience rigorous instruction, and interact with quality teachers. The middle school years are particularly significant for mathematics education since the courses students pursue during those years affect later access to rigorous mathematics coursework at the high ...
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Directory of Open Access Journals (Sweden)
Xuemeng Cao
2017-10-01
Full Text Available This article shows what achievements have been made by existing studies on graduate employability, and what gaps need to be filled in this field. It starts with a retrospective account of the changing concept of employability, followed by a presentation of the practices that have been used to support graduate employability enhancement in different countries. Moreover, this article gives a critical review of Chinese contexts of graduate labour market. Last but not least, limitations of existing studies are identified, which reflect an expectation for future research on graduate employability to meet the demand of an increasingly international dimension of higher education.
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Where are LIGO's Big Black Holes?
Fishbach, Maya; Holz, Daniel E.
2018-01-01
In LIGO's O1 and O2 observational runs, the detectors were sensitive to stellar mass binary black hole coalescences with component masses up to 100 M⊙, with binaries with primary masses above 40 M⊙ representing over 90% of the total accessible sensitive volume. Nonetheless, of the first 3.9 LIGO detections (GW150914, GW151226, GW170104, and LVT151012), the most massive binary detected was GW150914 with a primary component mass of ~ 36 M⊙ far below the detection mass limit. Furthermore, there are theoretical arguments in favor of an upper mass gap, predicting an absence of black holes in the mass range 50 constraints on the shape of the underlying mass distribution of LIGO's binary black holes. We fit a power-law distribution with an upper mass cutoff to real and simulated BBH mass measurements, finding that the first four detections favor shallow power law slopes α < 3 and an upper mass cutoff Mmax ~ 40 M⊙. We show that with ~10 additional LIGO BBH detections, fitting the BH mass distribution will provide strong evidence for an upper mass gap if one exists.
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Scalar-Tensor Black Holes Embedded in an Expanding Universe
Tretyakova, Daria; Latosh, Boris
2018-02-01
In this review we focus our attention on scalar-tensor gravity models and their empirical verification in terms of black hole and wormhole physics. We focus on a black hole, embedded in an expanding universe, describing both cosmological and astrophysical scales. We show that in scalar-tensor gravity it is quite common that the local geometry is isolated from the cosmological expansion, so that it does not backreact on the black hole metric. We try to extract common features of scalar-tensor black holes in an expanding universe and point out the gaps that must be filled.
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The renaissance of black phosphorus.
Ling, Xi; Wang, Han; Huang, Shengxi; Xia, Fengnian; Dresselhaus, Mildred S
2015-04-14
One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers, and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single-layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 eV to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field.
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Black holes and quantum processes in them
International Nuclear Information System (INIS)
Frolov, V.P.
1976-01-01
The latest achievements in the physics of black holes are reviewed. The problem of quantum production in a strong gravitational field of black holes is considered. Another parallel discovered during investigation of interactions between black holes and between black holes and surrounding media, is also drawn with thermodynamics. A gravitational field of rotating black holes is considered. Some cosmological aspects of evaporation of small black holes are discussed as well as possibilities to observe them
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Therapeutic Dimensions of the Black Aesthetic
Toldson, Ivory L.; Pasteur, Alfred B.
1976-01-01
The authors of this article see the black aesthetic largely in terms of the affective component. Emotional oneness which is foreign to the white world view is the means by which the black man can achieve optimal mental health and development. The therapeutic implications of the black aesthetic are outlined. (NG)
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Race, Socioeconomic Status, and Implicit Bias: Implications for Closing the Achievement Gap
Schlosser, Elizabeth Auretta Cox
This study accessed the relationship between race, socioeconomic status, age and the race implicit bias held by middle and high school science teachers in Mobile and Baldwin County Public School Systems. Seventy-nine participants were administered the race Implicit Association Test (race IAT), created by Greenwald, A. G., Nosek, B. A., & Banaji, M. R., (2003) and a demographic survey. Quantitative analysis using analysis of variances, ANOVA and t-tests were used in this study. An ANOVA was performed comparing the race IAT scores of African American science teachers and their Caucasian counterparts. A statically significant difference was found (F = .4.56, p = .01). An ANOVA was also performed using the race IAT scores comparing the age of the participants; the analysis yielded no statistical difference based on age. A t-test was performed comparing the race IAT scores of African American teachers who taught at either Title I or non-Title I schools; no statistical difference was found between groups (t = -17.985, p .001). This research examines the implications of the achievement gap among African American and Caucasian students in science.
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Closing the Racial Discipline Gap in Classrooms by Changing Teacher Practice
Gregory, Anne; Hafen, Christopher A.; Ruzek, Erik; Mikami, Amori Yee; Allen, Joseph P.; Pianta, Robert C.
2017-01-01
Black students are issued school discipline sanctions at rates higher than members of other racial and ethnic groups, underscoring the need for professional development that addresses this gap. In 86 secondary classrooms, a randomized controlled trial examined the effects of a 2-year teacher coaching program, My Teaching Partner Secondary (MTP-S). Results from the second year of coaching and the year after coaching was discontinued replicated previous findings from the first year of coaching—intervention teachers had no significant disparities in discipline referral between Black students and their classmates, compared to teachers in the control condition, for whom racial discipline gaps remained. Thus, MTP-S effects were replicated in the second year of coaching and maintained when coaching was withdrawn. Mediational analyses identified mechanisms for these effects; Black students had a low probability of receiving disciplinary referrals with teachers who increased skills to engage students in high-level analysis and inquiry. PMID:28190913
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Black Musicians Leading the Way.
Music Educators Journal, 1982
1982-01-01
Describes the careers and musical achievements of Blacks who were forerunners in jazz, blues, gospel, music, spirituals, band music, classical music, ragtime, and opera. The list was compiled to provide teachers with historical background information for "Black History Month." (AM)
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Evolution of the Black Hole Mass Function in Star Clusters from Multiple Mergers
Christian, Pierre; Mocz, Philip; Loeb, Abraham
2018-05-01
We investigate the effects of black hole (BH) mergers in star clusters on the black hole mass function (BHMF). As BHs are not produced in pair-instability supernovae, it is suggested that there is a dearth of high-mass stellar BHs. This dearth generates a gap in the upper end of the BHMF. Meanwhile, parameter fitting of X-ray binaries suggests the existence of a gap in the mass function under 5 solar masses. We show, through evolving a coagulation equation, that BH mergers can appreciably fill the upper mass gap, and that the lower mass gap generates potentially observable features at larger mass scales. We also explore the importance of ejections in such systems and whether dynamical clusters can be formation sites of intermediate-mass BH seeds.
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Andra Fakhrian
2016-01-01
Akeelah, a black American teenager, who faces many obstacles to achieve her purpose, to win the bee. Jibes, less attention from her mother, family, and even the roughness words are often heard by her until she becomes uncivilized. In the other side, Dylan-bourgeois with the bee’s tension are supported her pessimism to become unsure of her own ability. Moreover, a chronicle Gap Skin-Colors in America made people after she won the regional spelling bee. Thereof, Akeelah become...
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Stephens, Nicole M; Hamedani, MarYam G; Destin, Mesmin
2014-04-01
College students who do not have parents with 4-year degrees (first-generation students) earn lower grades and encounter more obstacles to success than do students who have at least one parent with a 4-year degree (continuing-generation students). In the study reported here, we tested a novel intervention designed to reduce this social-class achievement gap with a randomized controlled trial (N = 168). Using senior college students' real-life stories, we conducted a difference-education intervention with incoming students about how their diverse backgrounds can shape what they experience in college. Compared with a standard intervention that provided similar stories of college adjustment without highlighting students' different backgrounds, the difference-education intervention eliminated the social-class achievement gap by increasing first-generation students' tendency to seek out college resources (e.g., meeting with professors) and, in turn, improving their end-of-year grade point averages. The difference-education intervention also improved the college transition for all students on numerous psychosocial outcomes (e.g., mental health and engagement).
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Gender and Student Achievement in English Schools
Stephen Machin; Sandra McNally
2006-01-01
The widening gap between the average educational achievement of boys and girls has been the subject of much discussion. This gap is especially controversial for students taking national exams at the end of their compulsory education. However, the gender gap is also apparent at earlier and at later stages of education. In this paper, we analyse changes over time in the gender achievement gap at the different stages of compulsory education. We first use a combination of data sources to paint a ...
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Directory of Open Access Journals (Sweden)
Chaiyavat CHAIYASUT
Full Text Available Abstract The present study estimated the optimum germination conditions to achieve high content of Gamma-amino butyric acid (GABA and other phytochemicals in Thai black rice cultivar Kum Payao (BR. The Box–Behnken design of response surface methodology was employed to optimize the germination conditions. The changes in the GABA, phytochemical content, impact of salt, and temperature stress variation on phytochemical content, and stability of GABA were studied. The results showed that 12 h of soaking at pH 7, followed by 36 h of germination was the optimum condition to achieve maximum GABA content (0.2029 mg/g of germinated BR (GBR. The temperature (8 and 30 °C, and salt (50-200 mM NaCl content affected the phytochemicals of GBR, especially GABA, and anthocyanins. Obviously, the antioxidant capability, and enzyme (α-amylase and α-glucosidase inhibiting nature of BR was significantly (P < 0.001 increased after germination. The storage of GBR at 4 °C significantly, preserved the GABA content (∼80% for 45 days. Primarily, the current study revealed the changes in phytochemical content, and bioactivity of Thai black rice cr. Kum Payao during germination. More studies should be carried out on pharmacological benefits of GABA-rich GBR.
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THE MASS DISTRIBUTION OF STELLAR-MASS BLACK HOLES
International Nuclear Information System (INIS)
Farr, Will M.; Sravan, Niharika; Kalogera, Vicky; Cantrell, Andrew; Kreidberg, Laura; Bailyn, Charles D.; Mandel, Ilya
2011-01-01
We perform a Bayesian analysis of the mass distribution of stellar-mass black holes using the observed masses of 15 low-mass X-ray binary systems undergoing Roche lobe overflow and 5 high-mass, wind-fed X-ray binary systems. Using Markov Chain Monte Carlo calculations, we model the mass distribution both parametrically—as a power law, exponential, Gaussian, combination of two Gaussians, or log-normal distribution—and non-parametrically—as histograms with varying numbers of bins. We provide confidence bounds on the shape of the mass distribution in the context of each model and compare the models with each other by calculating their relative Bayesian evidence as supported by the measurements, taking into account the number of degrees of freedom of each model. The mass distribution of the low-mass systems is best fit by a power law, while the distribution of the combined sample is best fit by the exponential model. This difference indicates that the low-mass subsample is not consistent with being drawn from the distribution of the combined population. We examine the existence of a 'gap' between the most massive neutron stars and the least massive black holes by considering the value, M 1% , of the 1% quantile from each black hole mass distribution as the lower bound of black hole masses. Our analysis generates posterior distributions for M 1% ; the best model (the power law) fitted to the low-mass systems has a distribution of lower bounds with M 1% >4.3 M sun with 90% confidence, while the best model (the exponential) fitted to all 20 systems has M 1% >4.5 M sun with 90% confidence. We conclude that our sample of black hole masses provides strong evidence of a gap between the maximum neutron star mass and the lower bound on black hole masses. Our results on the low-mass sample are in qualitative agreement with those of Ozel et al., although our broad model selection analysis more reliably reveals the best-fit quantitative description of the underlying mass
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CASE STUDY: China — Bridging the Gap between Scientists and ...
International Development Research Centre (IDRC) Digital Library (Canada)
2011-01-05
Jan 5, 2011 ... CASE STUDY: China — Bridging the Gap between Scientists and ... the right inputs of water, fertilizer, and pesticides to maximize yields. ... Some are rare and unique to the area, such as black wax maize and mountain lily.
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Racial and Ethnic Infant Mortality Gaps and the Role of Socio-Economic Status
Elder, Todd E.; Goddeeris, John H.; Haider, Steven J.
2016-01-01
We assess the extent to which differences in socio-economic status are associated with racial and ethnic gaps in a fundamental measure of population health: the rate at which infants die. Using micro-level Vital Statistics data from 2000 to 2004, we examine mortality gaps of infants born to white, black, Mexican, Puerto Rican, Asian, and Native American mothers. We find that between-group mortality gaps are strongly and consistently (except for Mexican infants) associated with maternal marita...
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Zeisler, Kayla
2012-01-01
Research has shown that there is a gap in educational achievement between socioeconomic and racial groups in the public education system in the United States. This paper identifies the link between resources and academic achievement. Through examining educational resources, from in-school factors, such as facilities and teacher quality, to…
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Gender gap or program gap? Students' negotiations of study practice in a course in electromagnetism
Andersson, Staffan; Johansson, Anders
2016-12-01
[This paper is part of the Focused Collection on Gender in Physics.] This study of achievement differences, as reflected by course grades, on a third-semester electromagnetism course at a Swedish research university was motivated by instructor concerns about gender inequalities. Quantitative analysis showed a gender gap in course grades between female and male students for the period of fall 2007 to spring 2013. Dynamics behind this gap were explored through interpretative discourse analysis on interviews of 21 students who had recently passed the course. A recurring pattern was identified in the interviews. Students described studying electromagnetism as either studying to pass or studying to learn. Their choice of practice was influenced by the significance recognized in the course, which primarily was discussed in relation to program affiliation. Students stressed that perceived differences, in their study context, were larger between students affiliated with different programs than between male and female students on the same program. This was supported by quantitative analysis of course grades in relation to study programs, where the grade difference between female and male students on the same program in most cases were not statistically significant. The gender gap in grades for the whole course was related to different achievements on different programs. Programs further from the discipline of physics had lower mean grades and also enrolled a larger fraction of female students. Society-wide gender differences in interest and study choice are reflected in the grades on this single course. These results displace the achievement gap from the level of individuals to that of programs, and the gender gap from a difference in achievement to a difference in study choice. We discuss the implications of this shift of perspective in relation to gender differences for both research and teaching.
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Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik
2013-01-01
Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031
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Achieving biodiversity benefits with offsets: Research gaps, challenges, and needs.
Gelcich, Stefan; Vargas, Camila; Carreras, Maria Jose; Castilla, Juan Carlos; Donlan, C Josh
2017-03-01
Biodiversity offsets are becoming increasingly common across a portfolio of settings: national policy, voluntary programs, international lending, and corporate business structures. Given the diversity of ecological, political, and socio-economic systems where offsets may be applied, place-based information is likely to be most useful in designing and implementing offset programs, along with guiding principles that assure best practice. We reviewed the research on biodiversity offsets to explore gaps and needs. While the peer-reviewed literature on offsets is growing rapidly, it is heavily dominated by ecological theory, wetland ecosystems, and U.S.-based research. Given that majority of offset policies and programs are occurring in middle- and low-income countries, the research gaps we identified present a number of risks. They also present an opportunity to create regionally based learning platforms focused on pilot projects and institutional capacity building. Scientific research should diversify, both topically and geographically, in order to support the successful design, implementation, and monitoring of biodiversity offset programs.
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Home Media and Children’s Achievement and Behavior
Hofferth, Sandra L.
2010-01-01
This study provides a national picture of the time American 6–12 year olds spent playing video games, using the computer, and watching television at home in 1997 and 2003 and the association of early use with their achievement and behavior as adolescents. Girls benefited from computers more than boys and Black children’s achievement benefited more from greater computer use than did that of White children. Greater computer use in middle childhood was associated with increased achievement for White and Black girls and Black boys, but not White boys. Greater computer play was also associated with a lower risk of becoming socially isolated among girls. Computer use does not crowd out positive learning-related activities, whereas video game playing does. Consequently, increased video game play had both positive and negative associations with the achievement of girls but not boys. For boys, increased video game play was linked to increased aggressive behavior problems. PMID:20840243
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The achievement gap: Should we rely on SAT scores to tell us anything about it?
Directory of Open Access Journals (Sweden)
Dale Whittington
2004-04-01
Full Text Available Increasing numbers of students taking the SAT have declined to identify their race/ethnicity. I examined the impact of non-respondents on the validity of reported racial/ethnic differences and year-to-year changes in test performance. Using an analysis reported by Wainer (1988 and SAT data from 1996 to 2003, I confirmed Wainer’s findings that non-respondents prevent accurate estimations of group differences based on SAT data. I then explored the impact of College Board press release information on news reports about the achievement gap. I found frequent reports of racial/ethnic differences in SAT scores and year-to-year changes in scores but negligible consideration of non-respondents. Press releases and media reports should include information about non-respondents and their impact on accuracy of reported differences based on race/ethnicity.
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Closing the Minority Achievement Gap in Math
Holloway, John H.
2004-01-01
Minority students face numerous academic barriers for achievement in the classroom as well as outside the school. The National Council of Teachers of Mathematics (NCTM) suggests six principles for maintaining the standard of school mathematics.
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Bowleg, Lisa; English, Devin; del Rio-Gonzalez, Ana Maria; Burkholder, Gary J.; Teti, Michelle; Tschann, Jeanne M.
2016-01-01
Although extensive research documents that Black people in the U.S. frequently experience social discrimination, most of this research aggregates these experiences primarily or exclusively by race. Consequently, empirical gaps exist about the psychosocial costs and benefits of Black men?s experiences at the intersection of race and gender. Informed by intersectionality, a theoretical framework that highlights how multiple social identities intersect to reflect interlocking social-structural i...
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Black Self-Esteem and Desegregated Schools.
Drury, Darrel W.
1980-01-01
Discusses a study to determine attitudes among Black and White students in 194 southern high schools regarding desegregation. Data are presented on differences between schools; test-score achievement; and variations in self-esteem among students in predominantly White, Black, and racially mixed schools. Findings are interpreted in light of…
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Analogue Hawking radiation from astrophysical black-hole accretion
International Nuclear Information System (INIS)
Das, Tapas K
2004-01-01
We show that spherical accretion onto astrophysical black holes can be considered as a natural example of an analogue system. We provide, for the first time, an exact analytical scheme for calculating the analogue Hawking temperature and surface gravity for general relativistic accretion onto astrophysical black holes. Our calculation may bridge the gap between the theory of transonic astrophysical accretion and the theory of analogue Hawking radiation. We show that the domination of the analogue Hawking temperature over the actual Hawking temperature may be a real astrophysical phenomenon, though observational tests of this fact will at best be difficult and at worst might prove to be impossible. We also discuss the possibilities of the emergence of analogue white holes around astrophysical black holes. Our calculation is general enough to accommodate accreting black holes with any mass
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Mathematics Achievement by Immigrant Children
Directory of Open Access Journals (Sweden)
Gary G. Huang
2000-05-01
Full Text Available In this study, I examined academic achievement of immigrant children in the United States, Canada, England, Australia, and New Zealand. Analyzing data from the Third International Mathematics and Science Study (TIMSS, I gauged the performance gaps relating to the generation of immigration and the home language background. I found immigrant children's math and science achievement to be lower than the others only in England, the U.S., and Canada. Non-English language background was found in each country to relate to poor math and science learning and this disadvantage was stronger among native-born childrenpresumably children of indigenous groupsthan among immigrant children. I also examined the school variation in math performance gaps, using hierarchical linear modeling (HLM to each country's data. The patterns in which language- and generation-related math achievement gaps varied between schools are different in the five countries.
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Becoming Black Women: Intimate Stories and Intersectional Identities
Wilkins, Amy C.
2012-01-01
In this article, I argue that intimate stories are an important resource for the achievement of intersectional identities. Drawing on in-depth interviews with black college students at two predominantly white universities, I examine the stories black college women tell about interracial relationships between black men and white women. I argue that…
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Protective Factors as an Explanation for the "Paradox" of Black-White Differences in Heavy Drinking.
Mulia, Nina; Ye, Yu; Karriker-Jaffe, Katherine J; Zemore, Sarah E; Jones-Webb, Rhonda
2018-04-02
African Americans are generally known to have lower heavy drinking prevalence than Whites despite often greater individual and community risk factors. While it is supposed that their protective resources explain this "paradox," studies have not explicitly examined this. Assess the contribution of protective resources to Black-White differences in heavy drinking, and (secondarily) whether protective resources operate by reducing heavy drinking and/or increasing abstinence. Using data from the 2009-2010 U.S. National Alcohol Survey (N = 3,133 Whites and 1,040 Blacks ages 18+), we applied propensity score (PS) weighting to estimate racial differences in heavy drinking and abstinence under hypothetical conditions in which Whites are similar to Blacks in: (1) age and marital status; (2) socioeconomic position and unfair treatment; (3) neighborhood socioeconomic conditions and alcohol outlet density; and (4) protective resources (proscriptive religiosity, area-level religiosity, "drier" network drinking norms and patterns, and family social support). The Black-White gap in male and female drinkers' baseline heavy drinking increased after weighting adjustments for demographics. In women, this gap was reduced after weighting on disadvantage and eliminated after adjusting for protective resources. In men, adjustment for disadvantage increased the racial gap, and protective resources reduced it. Protective resources had a stronger effect on Black-White differences in men's abstinence than heavy drinking, but similar effects on these outcomes in women. Protective resources help explain Black-White differences in men's and particularly women's heavy drinking. Future research is needed to elucidate mechanisms of action and additional factors underlying racial differences in men's heavy drinking.
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Krentzman, Amy R.; Farkas, Kathleen J.; Townsend, Aloen L.
2012-01-01
This study addresses an unexplained finding in the alcoholism treatment field: despite the health and socioeconomic disparities that exist between blacks and whites at intake, blacks and whites achieve equivalent treatment outcomes. Using Project MATCH data, this study explores religiousness and spirituality as strengths in the African American community that may account in part for equivalent outcomes. Using binary logistic regression, this study found that as purpose in life increased, blacks were more likely to achieve sobriety than whites. This study provides evidence that purpose in life is a cultural strength and an advantage among blacks in achieving sobriety. PMID:22707846
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Adair, C.; Burt, Ramsay, 1953-
2016-01-01
British Dance: Black Routes re-examines the distinctive contributions made to British dance by dancers who are Black. Covering the period 1946 to the present, it presents a radical re-reading of dancers and their companies, placing their achievements within a broader historical, cultural and artistic context. The result of a two year research project, British Dance and the African Diaspora, led by editors Christy Adair and Ramsay Burt, the collection looks at artists working with contempor...
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Racial/Ethnic Test Score Gaps and the Urban Continuum
Gagnon, Douglas J.; Mattingly, Marybeth J.
2018-01-01
Research is just beginning to describe with precision determinants of racial and ethnic achievement gaps. Work by Reardon, Kalogrides, and Shores found that factors such as parental income, parental education, and segregation are the strongest predictors of achievement gaps. In this study we expand this line of inquiry to examine the role of…
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Where Are LIGO’s Big Black Holes?
Fishbach, Maya; Holz, Daniel E.
2017-12-01
In LIGO’s O1 and O2 observational runs, the detectors were sensitive to stellar-mass binary black hole (BBH) coalescences with component masses up to 100 {M}ȯ , with binaries with primary masses above 40 {M}ȯ representing ≳90% of the total accessible sensitive volume. Nonetheless, of the 5.9 detections (GW150914, LVT151012, GW151226, GW170104, GW170608, and GW170814) reported by LIGO-Virgo, the most massive binary detected was GW150914 with a primary component mass of ∼ 36 {M}ȯ , far below the detection mass limit. Furthermore, there are theoretical arguments in favor of an upper mass gap, predicting an absence of black holes in the mass range 50≲ M≲ 135 {M}ȯ . We argue that the absence of detected binary systems with component masses heavier than ∼ 40 {M}ȯ may be preliminary evidence for this upper mass gap. By allowing for the presence of a mass gap, we find weaker constraints on the shape of the underlying mass distribution of BBHs. We fit a power-law distribution with an upper mass cutoff to real and simulated BBH mass measurements, finding that the first 3.9 BBHs favor shallow power-law slopes α ≲ 3 and an upper mass cutoff {M}\\max ∼ 40 {M}ȯ . This inferred distribution is entirely consistent with the two recently reported detections, GW170608 and GW170814. We show that with ∼10 additional LIGO-Virgo BBH detections, fitting the BH mass distribution will provide strong evidence for an upper mass gap if one exists.
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Cunningham, Timothy J; Croft, Janet B; Liu, Yong; Lu, Hua; Eke, Paul I; Giles, Wayne H
2017-05-05
Although the overall life expectancy at birth has increased for both blacks and whites and the gap between these populations has narrowed, disparities in life expectancy and the leading causes of death for blacks compared with whites in the United States remain substantial. Understanding how factors that influence these disparities vary across the life span might enhance the targeting of appropriate interventions. Trends during 1999-2015 in mortality rates for the leading causes of death were examined by black and white race and age group. Multiple 2014 and 2015 national data sources were analyzed to compare blacks with whites in selected age groups by sociodemographic characteristics, self-reported health behaviors, health-related quality of life indicators, use of health services, and chronic conditions. During 1999-2015, age-adjusted death rates decreased significantly in both populations, with rates declining more sharply among blacks for most leading causes of death. Thus, the disparity gap in all-cause mortality rates narrowed from 33% in 1999 to 16% in 2015. However, during 2015, blacks still had higher death rates than whites for all-cause mortality in all groups aged blacks in age groups deaths among blacks (especially cardiovascular disease and cancer and their risk factors) across the life span and create equal opportunities for health.
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Closing the Knowledge Gap on Effective Professional Development
Guskey, Thomas R.
2009-01-01
Achievement gaps concern educators at all levels today. Educators recognize the threats these gaps pose to education quality and equity, and they are working hard to close them--but an equally threatening gap in education with consequences just as serious is largely ignored. It influences every educational-improvement effort and seriously…
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Culturally Responsive Social Skills Instruction for Adolescent Black Males
Robinson-Ervin, Porsha; Cartledge, Gwendolyn; Keyes, Starr
2011-01-01
The cultural disconnect between black males and the school environment has been correlated with poor academic achievement and high discipline rates for Black males. Instructional strategies that draw upon the learner?s cultural background hold promise as one means for intervention. This paper addresses the social skills needs of black adolescent…
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Vantieghem, Wendelien; Vermeersch, Hans; Van Houtte, Mieke
2014-01-01
Educational gender gap research tries to explain the differential achievement of boys and girls at secondary school, which manifests in many western countries. Several explanatory frameworks are used for this purpose, such as masculinities theory. In this review article, the history of educational gender gap research in Anglo-Saxon literature and…
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Challenging the Black Church Narrative: Race, Class, and Homosexual Attitudes.
Irizarry, Yasmiyn A; Perry, Ravi K
2018-01-01
In recent years, scholars have pointed to the Black church as the driving force behind Blacks' more conservative lesbian, gay, bisexual, and transgendered (LGBT) attitudes. Although evidence suggests a robust association between religiosity and LGBT attitudes, contemporary scholarship has not examined the role of class or the extent to which religiosity actually explains these trends. Using the 2004-2014 waves of the General Social Survey, we find that class moderates in the effect of race on negative LGBT attitudes, resulting in a noticeably larger gap between middle-class Blacks and Whites than in the top or the bottom of the class distribution. Although religiosity and moralization explain a portion of racial differences in homosexual attitudes across class groups, we find that neither fully accounts for the more conservative attitudes of the Black middle class. We conclude by discussing the shortcomings of these narratives for understanding Blacks' more conservative LGBT attitudes.
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Tough or Tender: (Dis)Similarities in White College Students' Perceptions of Black and White Women
Donovan, Roxanne A.
2011-01-01
Although intersectional theory and empirical evidence suggest that race impacts how women are perceived, there is a dearth of research on how the dominant culture stereotypes Black women compared to White women. The current study addresses this gap using an intersectional framework to investigate White college students' stereotypes of Black and…
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Posey-Maddox, Linn
2017-01-01
Few studies have explored the engagement of fathers in children's schooling. Understanding the role that black fathers, in particular, play in their children's education is both important and timely given the persistent opportunity gaps faced by many black students in the US and the influential role that black fathers can play in their children's…
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Black hole thermodynamics and time asymmetry
Energy Technology Data Exchange (ETDEWEB)
Davies, P C.W. [King' s Coll., London (UK). Dept. of Mathematics
1976-10-01
The role of the gravitational field as a source of entropy is discussed, first in connection with cosmology, then for black holes. A review is given of the need for an assumption of 'molecular' chaos or randomness at the initial cosmological singularity, in order to achieve consistency of statistical mechanics with the observed time asymmetry in the universe. It is argued that a simple randomness assumption cannot always be made, because several singularities may be casually connected. The situation is compared with that of quantum black and white holes confined in a closed box. The possibility of black-hole fluctuations is discussed, together with Hawking's conjecture that black and white holes are indistinguishable.
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Young, Gifted, and Black: Promoting High Achievement among African-American Students.
Perry, Theresa; Steele, Claude; Hilliard, Asa G., III
In three linked but separate essays, this book explores how African-American students experience school in a society that has historically devalued their intellectual abilities. It calls for a new understanding of the unique obstacles black students face in American schools and points to a variety of educational practices that can mitigate those…
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Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.
Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J
2014-11-28
Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet. Copyright © 2014, American Association for the Advancement of Science.
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Dirt on My Record: Rethinking Disciplinary Practices in an All-Black, All-Male Alternative Class
Nasir, Na'Ilah Suad; Ross, Kihana Miraya; McKinney de Royston, Maxine; Givens, Jarvis; Bryant, Jalessa N.
2013-01-01
In this empirical study, the authors draw on classroom observations and interviews with twenty-three Black male ninth graders in an urban district to focus on the nature of disciplinary practices in an all-Black, all-male manhood development class. While scholars have identified the "discipline gap" as a salient aspect of the experience…
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Black phosphorus saturable absorber for ultrashort pulse generation
Energy Technology Data Exchange (ETDEWEB)
Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, Wroclaw 50-370 (Poland); Macherzynski, W.; Paletko, P. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroclaw 50-372 (Poland)
2015-08-03
Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ∼300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics.
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Black-white differences in the economic value of improving health.
Murphy, Kevin M; Topel, Robert H
2005-01-01
This article examines how differences in longevity over time and across groups add to the typical measures of economic progress and intergroup differentials. We focus on gains for and differences between groups defined both by race (black and white) and by gender, relying on willingness to pay as our measure of the economic value of gains in longevity. Measured at birth, the gains for white males between 1968 and 1998 were about 245,000 dollars per person, while the gains for black males were far larger, about 390,000 dollars per person. The gains for women were somewhat smaller, with white females gaining about 150,000 dollars per person and black females gaining about 305,000 dollars per person. Our estimates suggest that differences in income explain about 1/3 to 1/2 of the current black-white gap in longevity.
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Public Perceptions of the Pay Gap
Hill, Catherine; Silva, Elena
2005-01-01
Women have made gains toward closing the gender pay gap during the past two decades. Much of the progress occurred during the 1980s, with smaller gains in the 1990s (Institute for Women's Policy Research 2004). Women's achievements in higher education are partly responsible for narrowing the pay gap in the 1980s and 1990s. As more women earned…
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Gender Gaps in Achievement and Participation in Multiple Introductory Biology Classrooms
Eddy, Sarah L.; Brownell, Sara E.; Wenderoth, Mary Pat
2014-01-01
Although gender gaps have been a major concern in male-dominated science, technology, engineering, and mathematics disciplines such as physics and engineering, the numerical dominance of female students in biology has supported the assumption that gender disparities do not exist at the undergraduate level in life sciences. Using data from 23 large…
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Comparing Novel Multi-Gap Resistive Plate Chamber Models
Stien, Haley; EIC PID Consortium Collaboration
2016-09-01
Investigating nuclear structure has led to the fundamental theory of Quantum Chromodynamics. An Electron Ion Collider (EIC) is a proposed accelerator that would further these investigations. In order to prepare for the EIC, there is an active detector research and development effort. One specific goal is to achieve better particle identification via improved Time of Flight (TOF) detectors. A promising option is the Multi-Gap Resistive Plate Chamber (mRPC). These detectors are similar to the more traditional RPCs, but their active gas gaps have dividers to form several thinner gas gaps. These very thin and accurately defined gas gaps improve the timing resolution of the chamber, so the goal is to build an mRPC with the thinnest gaps to achieve the best possible timing resolution. Two different construction techniques have been employed to make two mRPCs. The first technique is to physically separate the gas gaps with sheets of glass that are .2mm thick. The second technique is to 3D print the layered gas gaps. A comparison of these mRPCs and their performances will be discussed and the latest data presented. This research was supported by US DOE MENP Grant DE-FG02-03ER41243.
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Hidden Pair of Supermassive Black Holes
Kohler, Susanna
2015-08-01
Could a pair of supermassive black holes (SMBHs) be lurking at the center of the galaxy Mrk 231? A recent study finds that this may be the case and the unique spectrum of this galaxy could be the key to discovering more hidden binary SMBH systems.Where Are the Binary Supermassive Black Holes?Its believed that most, if not all, galaxies have an SMBH at their centers. As two galaxies merge, the two SMBHs should evolve into a closely-bound binary system before they eventually merge. Given the abundance of galaxy mergers, we would expect to see the kinematic and visual signatures of these binary SMBHs among observed active galactic nuclei yet such evidence for sub-parsec binary SMBH systems remains scarce and ambiguous. This has led researchers to wonder: is there another way that we might detect these elusive systems?A collaboration led by Chang-Shuo Yan (National Astronomical Observatories, Chinese Academy of Sciences) thinks that there is. The group suggests that these systems might have distinct signatures in their optical-to-UV spectra, and they identify a system that might be just such a candidate: Mrk 231.A Binary CandidateProposed model of Mrk 231. Two supermassive black holes, each with their own mini-disk, orbit each other in the center of a circumbinary disk. The secondary black hole has cleared gap in the circumbinary disk as a result of its orbit around the primary black hole. [Yan et al. 2015]Mrk 231 is a galaxy with a disturbed morphology and tidal tails strong clues that it might be in the final stages of a galactic merger. In addition to these signs, Mrk 231 also has an unusual spectrum for a quasar: its continuum emission displays an unexpected drop in the near-UV band.Yan and her collaborators propose that the odd behavior of Mrk 231s spectrum can be explained if the center of the galaxy houses a pair of SMBHs each with its own mini accretion disk surrounded by a circumbinary accretion disk. As the secondary SMBH orbits the primary SMBH (with a
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Liu, Xinke; Ang, Kah-Wee; Yu, Wenjie; He, Jiazhu; Feng, Xuewei; Liu, Qiang; Jiang, He; Dan Tang; Wen, Jiao; Lu, Youming; Liu, Wenjun; Cao, Peijiang; Han, Shun; Wu, Jing; Liu, Wenjun; Wang, Xi; Zhu, Deliang; He, Zhubing
2016-04-22
Black phosphorus (BP) has emerged as a promising two-dimensional (2D) material for next generation transistor applications due to its superior carrier transport properties. Among other issues, achieving reduced subthreshold swing and enhanced hole mobility simultaneously remains a challenge which requires careful optimization of the BP/gate oxide interface. Here, we report the realization of high performance BP transistors integrated with HfO2 high-k gate dielectric using a low temperature CMOS process. The fabricated devices were shown to demonstrate a near ideal subthreshold swing (SS) of ~69 mV/dec and a room temperature hole mobility of exceeding >400 cm(2)/Vs. These figure-of-merits are benchmarked to be the best-of-its-kind, which outperform previously reported BP transistors realized on traditional SiO2 gate dielectric. X-ray photoelectron spectroscopy (XPS) analysis further reveals the evidence of a more chemically stable BP when formed on HfO2 high-k as opposed to SiO2, which gives rise to a better interface quality that accounts for the SS and hole mobility improvement. These results unveil the potential of black phosphorus as an emerging channel material for future nanoelectronic device applications.
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DEFF Research Database (Denmark)
Langkjær, Michael Alexander
2012-01-01
Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as is hi...
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Topology, entropy, and Witten index of dilaton black holes
International Nuclear Information System (INIS)
Gibbons, G.W.; Kallosh, R.E.
1995-01-01
We have found that for extreme dilaton black holes an inner boundary must be introduced in addition to the outer boundary to give an integer value to the Euler number. The resulting manifolds have (if one identifies imaginary time) a topology S 1 xRxS 2 and Euler number χ=0 in contrast with the nonextreme case with χ=2. The entropy of extreme U(1) dilaton black holes is already known to be zero. We include a review of some recent ideas due to Hawking on the Reissner-Nordstroem case. By regarding all extreme black holes as having an inner boundary, we conclude that the entropy of all extreme black holes, including [U(1)] 2 black holes, vanishes. We discuss the relevance of this to the vanishing of quantum corrections and the idea that the functional integral for extreme holes gives a Witten index. We have studied also the topology of ''moduli space'' of multi-black-holes. The quantum mechanics on black hole moduli spaces is expected to be supersymmetric despite the fact that they are not hyper-Kaehler since the corresponding geometry has a torsion unlike the BPS monopole case. Finally, we describe the possibility of extreme black hole fission for states with an energy gap. The energy released, as a proportion of the initial rest mass, during the decay of an electromagnetic black hole is 300 times greater than that released by the fission of a 235 U nucleus
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Last hired, first fired? Black-white unemployment and the business cycle.
Couch, Kenneth A; Fairlie, Robert
2010-02-01
Studies have tested the claim that blacks are the last hired during periods of economic growth and the first fired in recessions by examining the movement of relative unemployment rates over the business cycle. Any conclusion drawn from this type of analysis must be viewed as tentative because cyclical movements in the underlying transitions into and out of unemployment are not examined. Using Current Population Survey data matched across adjacent months from 1989-2004, this article provides the first detailed examination of labor market transitions for prime-age black and white men to test the last hired, first fired hypothesis. Considerable evidence is presented that blacks are the first fired as the business cycle weakens. However no evidence is found that blacks are the last hired. Instead, blacks appear to be initially hired from the ranks of the unemployed early in the business cycle and later are drawn from nonparticipation. The narrowing of the racial unemployment gap near the peak of the business cycle is driven by a reduction in the rate of job loss for blacks rather than increases in hiring.
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International Nuclear Information System (INIS)
DREES, A.; AHRENS, L.; III FLILLER, R.; GASSNER, D.; MCINTYRE, G.T.; MICHNOFF, R.; TRBOJEVIC, D.
2002-01-01
During the RHIC Au-run in 2001 the 200 MHz storage cavity system was used for the first time. The rebucketing procedure caused significant beam debunching in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam could account for approximately 30%-40% of the total beam intensity. Some of it will be in the abort gap. In order to minimize the risk of magnet quenching due to uncontrolled beam losses at the time of a beam dump, a combination of a fast transverse kicker and copper collimators were used to clean the abort gap. This report gives an overview of the gap cleaning procedure and the achieved performance
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Study of energy determination of gamma-ray observed with an emulsion chamber with a large gap
International Nuclear Information System (INIS)
Inui, Tamiki; Otsuka, Taeko; Masaoka, Akiko
1982-01-01
The development of large size emulsion chambers has been made to study very high energy events. For this purpose, the chambers with exchangeable light sensitive layers are considered. The chambers have large gap for the exchange. In this case, it becomes hard to determine the energy of cascade shower. In this report, the authors describe on the experimental examples observed at Mt. Chacaltaya. The effect of a gap was investigated by these examples, and the simulation method by Okamoto and Shibata was applied to the chamber. The chamber used for the observation consisted of the top chamber of 11 c.u. and the bottom chamber of 15 c.u. There was a large gap of 170 cm between two chambers. Twelve showers in three families observed by this system were analyzed. The difference between the blackness in the top and bottom films was studied quantitatively. The blackness was calibrated for the electron density. Four methods of energy determination were studied. Among them, a method to employ the sum of the maximum blackness of a top film and that of a bottom one was used for the analysis. This method seemed to be more reliable than the old method. It was found by a simulation calculation that the recovery of shower in the bottom chamber was seen not only by hardrons but also by gamma-ray. (Kato, T.)
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Single particle studies of black liquor gasification under pressurized conditions
Energy Technology Data Exchange (ETDEWEB)
Whitty, K; Backman, R; Hupa, M; Backman, P; Ek, P; Hulden, S T; Kullberg, M; Sorvari, V
1997-10-01
The purpose of this project is to provide experimental data relevant to pressurized black liquor gasification concepts. Specifically, the following two goals will be achieved: Data on swelling, char yields and component release during pressurized pyrolysis of small samples of black liquor will be obtained. The reactivity and physical behavior of single black liquor droplets during simultaneous pyrolysis and gasification will be investigated. The structure and composition of black liquor char during formation and conversion will be studied. (orig.)
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Black hole spectra in holography: Consequences for equilibration of dual gauge theories
Directory of Open Access Journals (Sweden)
Alex Buchel
2015-07-01
Full Text Available For a closed system to equilibrate from a given initial condition there must exist an equilibrium state with the energy equal to the initial one. Equilibrium states of a strongly coupled gauge theory with a gravitational holographic dual are represented by black holes. We study the spectrum of black holes in Pilch–Warner geometry. These black holes are holographically dual to equilibrium states of strongly coupled SU(N N=2⁎ gauge theory plasma on S3 in the planar limit. We find that there is no energy gap in the black hole spectrum. Thus, there is a priori no obstruction for equilibration of arbitrary low-energy states in the theory via a small black hole gravitational collapse. The latter is contrasted with phenomenological examples of holography with dual four-dimensional CFTs having non-equal central charges in the stress–energy tensor trace anomaly.
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The theory of optical black hole lasers
Energy Technology Data Exchange (ETDEWEB)
Gaona-Reyes, José L., E-mail: jgaona@fis.cinvestav.mx; Bermudez, David, E-mail: dbermudez@fis.cinvestav.mx
2017-05-15
The event horizon of black holes and white holes can be achieved in the context of analogue gravity. It was proven for a sonic case that if these two horizons are close to each other their dynamics resemble a laser, a black hole laser, where the analogue of Hawking radiation is trapped and amplified. Optical analogues are also very successful and a similar system can be achieved there. In this work we develop the theory of optical black hole lasers and prove that the amplification is also possible. Then, we study the optical system by determining the forward propagation of modes, obtaining an approximation for the phase difference which governs the amplification, and performing numerical simulations of the pulse propagation of our system. - Highlights: • We develop the conditions to obtain the kinematics of the optical black hole laser. • We prove the amplification of Hawking radiation for the optical case. • We derive the forward propagation of modes and check the result of the backward case. • A model is proposed to calculate the phase difference and the amplification rate. • We perform numerical simulations of a pulse between two solitons forming a cavity.
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Rutkowski, David; Rutkowski, Leslie; Plucker, Jonathan A.
2012-01-01
A recent study in the USA documented the existence and growth of "excellence gaps" among students. These gaps are similar to the minimum competency achievement gaps that proliferate in policy discussions in many Western countries, but excellence gaps focus on the highest level of achievement rather than minimum competency. We extend this…
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Eikonal instability of Gauss-Bonnet-(anti-)-de Sitter black holes
Konoplya, R. A.; Zhidenko, A.
2017-05-01
Here we have shown that asymptotically anti-de Sitter (AdS) black holes in the Einstein-Gauss-Bonnet (GB) theory are unstable under linear perturbations of space-time in some region of parameters. This (eikonal) instability develops at high multipole numbers. We found the exact parametric regions of the eikonal instability and extended this consideration to asymptotically flat and de Sitter cases. The approach to the threshold of instability is driven by purely imaginary quasinormal modes, which are similar to those found recently in Grozdanov, Kaplis, and Starinets, [J. High Energy Phys. 07 (2016) 151, 10.1007/JHEP07(2016)151] for the higher curvature corrected black hole with the planar horizon. The found instability may indicate limits of holographic applicability of the GB-AdS backgrounds. Recently, through the analysis of critical behavior in AdS space-time in the presence of the Gauss-Bonnet term, it was shown [Deppe et al, Phys. Rev. Lett. 114, 071102 (2015), 10.1103/PhysRevLett.114.071102], that, if the total energy content of the AdS space-time is small, then no black holes can be formed with mass less than some critical value. A similar mass gap was also found when considering collapse of mass shells in asymptotically flat Gauss-Bonnet theories [Frolov, Phys. Rev. Lett. 115, 051102 (2015), 10.1103/PhysRevLett.115.051102]. The found instability of all sufficiently small Einstein-Gauss-Bonnet-AdS, dS and asymptotically flat black holes may explain the existing mass gaps in their formation.
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Recent advances on bioactivities of black rice.
Dias, Aécio L de S; Pachikian, Barbara; Larondelle, Yvan; Quetin-Leclercq, Joëlle
2017-11-01
Black rice has been consumed for centuries in Asian countries such as China, Korea or Japan. Nowadays, extracts and derivatives are considered as beneficial functional foods because of their high content in several bioactive molecules such as anthocyanins, other phenolics and terpenoids. The purpose of this review is to summarize and discuss recent developments on black rice bioactivities. Some sterols and triterpenoids with potential anticancer properties already tested in vitro and in vivo have been isolated and identified from bran extracts of black rice. Protection against osteoporosis has been suggested for the first time for black rice extracts. Because of its antioxidant and anti-inflammatory properties, black rice also protects liver and kidney from injuries. One clinical study reported the interest of black rice in case of alcohol withdrawal. Several advances have been recently achieved on the understanding of the potential biological effects of black rice and its derivatives. They further confirm that black rice should be considered as a promising source of health-promoting functional foods targeting a large set of noninfectious diseases. However, more clinical studies are needed to support the findings highlighted in this review.
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Devalued Black and Latino Racial Identities: A By-Product of STEM College Culture?
McGee, Ebony O.
2016-01-01
At some point most Black and Latino/a college students--even long-term high achievers--question their own abilities because of multiple forms of racial bias. The 38 high-achieving Black and Latino/a STEM study participants, who attended institutions with racially hostile academic spaces, deployed an arsenal of strategies (e.g., stereotype…
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The Gamma Gap and All-Cause Mortality
Juraschek, Stephen P.; Moliterno, Alison R.; Checkley, William; Miller, Edgar R.
2015-01-01
Background The difference between total serum protein and albumin, i.e. the gamma gap, is a frequently used clinical screening measure for both latent infection and malignancy. However, there are no studies defining a positive gamma gap. Further, whether it is an independent risk factor of mortality is unknown. Methods and Findings This study examined the association between gamma gap, all-cause mortality, and specific causes of death (cardiovascular, cancer, pulmonary, or other) in 12,260 participants of the National Health and Nutrition Examination Survey (NHANES) from 1999–2004. Participants had a comprehensive metabolic panel measured, which was linked with vital status data from the National Death Index. Cause of death was based on ICD10 codes from death certificates. Analyses were performed with Cox proportional hazards models adjusted for mortality risk factors. The mean (SE) age was 46 (0.3) years and the mean gamma gap was 3.0 (0.01) g/dl. The population was 52% women and 10% black. During a median follow-up period of 4.8 years (IQR: 3.3 to 6.2 years), there were 723 deaths. The unadjusted 5-year cumulative incidences across quartiles of the gamma gap (1.7–2.7, 2.8–3.0, 3.1–3.2, and 3.3–7.9 g/dl) were 5.7%, 4.2%, 5.5%, and 7.8%. After adjustment for risk factors, participants with a gamma gap of ≥3.1 g/dl had a 30% higher risk of death compared to participants with a gamma gap gap (per 1.0 g/dl) was most strongly associated with death from pulmonary causes (HR 2.22; 95%CI: 1.19, 4.17; P = 0.01). Conclusions The gamma gap is an independent risk factor for all-cause mortality at values as low as 3.1 g/dl (in contrast to the traditional definition of 4.0 g/dl), and is strongly associated with death from pulmonary causes. Future studies should examine the biologic pathways underlying these associations. PMID:26629820
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Interior structure of rotating black holes. III. Charged black holes
International Nuclear Information System (INIS)
Hamilton, Andrew J. S.
2011-01-01
This paper extends to the case of charged rotating black holes the conformally stationary, axisymmetric, conformally separable solutions presented for uncharged rotating black holes in a companion paper. In the present paper, the collisionless fluid accreted by the black hole may be charged. The charge of the black hole is determined self-consistently by the charge accretion rate. As in the uncharged case, hyper-relativistic counterstreaming between ingoing and outgoing streams drives inflation at (just above) the inner horizon, followed by collapse. If both ingoing and outgoing streams are charged, then conformal separability holds during early inflation, but fails as inflation develops. If conformal separability is imposed throughout inflation and collapse, then only one of the ingoing and outgoing streams can be charged: the other must be neutral. Conformal separability prescribes a hierarchy of boundary conditions on the ingoing and outgoing streams incident on the inner horizon. The dominant radial boundary conditions require that the incident ingoing and outgoing number densities be uniform with latitude, but the charge per particle must vary with latitude such that the incident charge densities vary in proportion to the radial electric field. The subdominant angular boundary conditions require specific forms of the incident number- and charge-weighted angular motions. If the streams fall freely from outside the horizon, then the prescribed angular conditions can be achieved by the charged stream, but not by the neutral stream. Thus, as in the case of an uncharged black hole, the neutral stream must be considered to be delivered ad hoc to just above the inner horizon.
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The Role of Fathers in the Lives of Black Women of Achievement.
Willie, Charles V.; Lane, Jolene A.
2001-01-01
Investigated fathers' roles in the lives of successful black women using life history case studies. Fathers were proud of and confident in their daughters, and most performed the role of mentor. Fathers gave daughters a sense of security that helped them succeed because they were not afraid to risk failure. Most fathers were interested in…
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Do male and female black-backed woodpeckers respond differently to gaps in habitat?
Jennifer Pierson; Fred W. Allendorf; Vicki Saab; Pierre Drapeau; Michael K. Schwartz
2010-01-01
We used population- and individual-based genetic approaches to assess barriers to movement in black-backed woodpeckers (Picoides arcticus), a fire-specialist that mainly occupies the boreal forest in North America. We tested if male and female woodpeckers exhibited the same movement patterns using both spatially implicit and explicit genetic analyses to define...
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Representation and Salary Gaps by Race-Ethnicity and Gender at Selective Public Universities
Li, Diyi; Koedel, Cory
2017-01-01
We use data from 2015-2016 to document faculty representation and wage gaps by race-ethnicity and gender in six fields at selective public universities. Consistent with widely available information, Black, Hispanic, and female professors are underrepresented and White and Asian professors are overrepresented in our data. Disadvantaged minority and…
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Energy Technology Data Exchange (ETDEWEB)
Ha, Kwang Soon, E-mail: tomo@kaeri.re.kr [Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Cheung, Fan-Bill [The Pennsylvania State University, University Park, PA 16802 (United States); Park, Rae Joon; Kim, Sang Baik [Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)
2012-12-15
Highlights: Black-Right-Pointing-Pointer Two-phase natural circulation flow induced in insulation gap was investigated. Black-Right-Pointing-Pointer Half-scaled non-heating experiments were performed to evaluate flow behavior. Black-Right-Pointing-Pointer The loop-integrated momentum equation was formulated and solved asymptotically. Black-Right-Pointing-Pointer First-order approximate solution was obtained and agreed with experimental data. - Abstract: The process of two-phase natural circulation flow induced in the annular gap between the reactor vessel and the insulation under external reactor vessel cooling conditions was investigated experimentally and analytically in this study. HERMES-HALF experiments were performed to observe and quantify the induced two-phase natural circulation flow in the annular gap. A half-scaled non-heating experimental facility was designed by utilizing the results of a scaling analysis to simulate the APR1400 reactor and its insulation system. The behavior of the boiling-induced two-phase natural circulation flow in the annular gap was observed, and the liquid mass flow rates driven by the natural circulation loop and the void fraction distribution were measured. Direct flow visualization revealed that choking would occur under certain flow conditions in the minimum gap region near the shear keys. Specifically, large recirculation flows were observed in the minimum gap region for large air injection rates and small outlet areas. Under such conditions, the injected air could not pass through the minimum gap region, resulting in the occurrence of choking near the minimum gap with a periodical air back flow being generated. Therefore, a design modification of the minimum gap region needs to be done to facilitate steam venting and to prevent choking from occurring. To complement the HERMES-HALF experimental effort, an analytical study of the dependence of the induced natural circulation mass flow rate on the inlet area and the
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Size and strain tunable band alignment of black-blue phosphorene lateral heterostructures.
Li, Yan; Ma, Fei
2017-05-17
Single-element lateral heterostructures composed of black and blue phosphorene are not only free from lattice mismatch but also exhibit rich physical properties related to the seamlessly stitched interfaces, providing the building blocks for designing atomically thin devices. Using first-principles calculations, we investigate the influence of interface structure, size effect and strain engineering on the electronic structure, effective masses and band alignment of black-blue phosphorene lateral heterostructures. The lateral heterostructure with an octatomic-ring interface presents a strong metallic feature due to the interface states, while a metal-semiconductor transition takes place in the system with a hexatomic-ring interface upon hydrogen passivation. Following a reciprocal scaling law, the band gap is tuned in a wide energy range by synchronously increasing the widths of black and blue phosphorene or by only widening that of black phosphorene. Moreover, type-II band alignment is observed in the width ranges of 2.0-3.1 nm and 3.7-4.2 nm, out of which it is type-I. However, the band gap and effective masses show small changes if only the width of blue phosphorene is altered. When the lateral heterostructure is tensile loaded, the effective mass ratio of hole to electron is enlarged by an order of magnitude at a strain of 4% along the zigzag direction. Meanwhile, the band alignment undergoes a crossover from type-I to type-II at a strain of 2%, facilitating efficient electron-hole separation for light detection and harvesting.
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Virtual gap dielectric wall accelerator
Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A
2013-11-05
A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.
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A new type of artificial structure to achieve broadband omnidirectional acoustic absorption
Zheng, L.-Y.; Wu, Y.; Zhang, X.-L.; Ni, X.; Chen, Z.-G.; Lu, M.-H.; Chen, Y.-F.
2013-01-01
We present a design for a two-dimensional omnidirectional acoustic absorber that can achieve 98.6% absorption of acoustic waves in water, forming an effective acoustic black hole. This artificial black hole consists of an absorptive core coated
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Stacking dependence of carrier transport properties in multilayered black phosphorous
Sengupta, A.; Audiffred, M.; Heine, T.; Niehaus, T. A.
2016-02-01
We present the effect of different stacking orders on carrier transport properties of multi-layer black phosphorous. We consider three different stacking orders AAA, ABA and ACA, with increasing number of layers (from 2 to 6 layers). We employ a hierarchical approach in density functional theory (DFT), with structural simulations performed with generalized gradient approximation (GGA) and the bandstructure, carrier effective masses and optical properties evaluated with the meta-generalized gradient approximation (MGGA). The carrier transmission in the various black phosphorous sheets was carried out with the non-equilibrium green’s function (NEGF) approach. The results show that ACA stacking has the highest electron and hole transmission probabilities. The results show tunability for a wide range of band-gaps, carrier effective masses and transmission with a great promise for lattice engineering (stacking order and layers) in black phosphorous.
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Mattison, Erica; Aber, Mark S
2007-09-01
This study investigated the relationship between school racial climate and students' self-reports of academic and discipline outcomes, including whether racial climate mediated and/or moderated the relationship between race and outcomes. Using the Racial Climate Survey-High School Version (M. Aber et al., unpublished), data were gathered from African American (n = 382) and European American students (n = 1456) regarding their perceptions of racial climate. About 18% of the respondents were low-income and approximately 50% were male. Positive perceptions of the racial climate were associated with higher student achievement and fewer discipline problems. Further, race moderated the relationship between racial climate and both achievement and discipline outcomes. Finally, racial differences in students' grades and discipline outcomes were associated with differences in perceptions of racial climate. Results suggest careful attention should be given to the racial climate of secondary schools, particularly for adolescents who perceive schools as unfair.
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Incarceration and Black-White inequality in Homeownership: A state-level analysis.
Schneider, Daniel; Turney, Kristin
2015-09-01
Rising incarceration rates in the United States, as well as the concentration of incarceration among already marginalized individuals, has led some scholars to suggest that incarceration increases economic inequality among American men. But little is known about the consequences of incarceration for wealth, about incarceration's contribution to Black-White disparities in wealth, or about the broader effects of incarceration on communities. In this article, we use state-level panel data (from 1985 to 2005) to examine the relationship between incarceration rates and the Black-White gap in homeownership, a distinct and important measure of wealth. Results, which are robust to an array of model specifications and robustness checks, show that incarceration rates diminish homeownership rates among Blacks and, in doing so, widen Black-White inequalities in homeownership. Therefore, the findings suggest that the consequences of incarceration extend beyond the offender and may increase inequality in household wealth. Copyright © 2015 Elsevier Inc. All rights reserved.
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Regular black holes in Einstein-Gauss-Bonnet gravity
Ghosh, Sushant G.; Singh, Dharm Veer; Maharaj, Sunil D.
2018-05-01
Einstein-Gauss-Bonnet theory, a natural generalization of general relativity to a higher dimension, admits a static spherically symmetric black hole which was obtained by Boulware and Deser. This black hole is similar to its general relativity counterpart with a curvature singularity at r =0 . We present an exact 5D regular black hole metric, with parameter (k >0 ), that interpolates between the Boulware-Deser black hole (k =0 ) and the Wiltshire charged black hole (r ≫k ). Owing to the appearance of the exponential correction factor (e-k /r2), responsible for regularizing the metric, the thermodynamical quantities are modified, and it is demonstrated that the Hawking-Page phase transition is achievable. The heat capacity diverges at a critical radius r =rC, where incidentally the temperature is maximum. Thus, we have a regular black hole with Cauchy and event horizons, and evaporation leads to a thermodynamically stable double-horizon black hole remnant with vanishing temperature. The entropy does not satisfy the usual exact horizon area result of general relativity.
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Cause-specific contributions to black-white differences in male mortality from 1960 to 1995
Directory of Open Access Journals (Sweden)
2004-04-01
Full Text Available Between 1960 and 1995 the black-white difference in male life expectancy in the United States increased from 6.7 years to 8.2 years. To provide insights into why mortality trends have been more adverse for black men than for white men, we investigate which causes of death were principally responsible for changes in the black-white difference in male mortality at ages 15-64 between 1960 and 1995. We find that black-white differences in male mortality varied substantially during this period. The gap increased in the 1960s, declined in the 1970s, and widened in the 1980s-early 1990s. Our findings reveal considerable variation in black-white disparities by cause of death and by age, as well as changes in the relative importance of various causes of death to the black-white male mortality disparity over time. The results suggest that consequences of black-white differences in socioeconomic status, access to quality health care, living conditions, and residential segregation vary by cause of death.
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Trayvon Martin: Racial Profiling, Black Male Stigma, and Social Work Practice.
Teasley, Martell Lee; Schiele, Jerome H; Adams, Charles; Okilwa, Nathern S
2018-01-01
To address a critical gap in the social work literature, this article examines the deleterious effects of racial profiling as it pertains to police targeting of male African Americans. The authors use the Trayvon Martin court case to exemplify how racial profiling and black male stigma help perpetuate social inequality and injustice for black men. A racism-centered perspective is examined historically and contemporarily as a theoretical approach to understanding the role that race plays in social injustice through racial profiling. Implications for social work research design and practice aimed at increasing the social work knowledge base on racial profiling are discussed. The authors call for attention and advocacy by major social work organizations in the reduction of black male stigma and racial profiling. © 2017 National Association of Social Workers.
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Unfolding the Intra-organisational Perception Gap in Decision-Making
DEFF Research Database (Denmark)
Zhao, Shasha; Papanastassiou, Marina; Bassiakos, Yiannis
2018-01-01
of a perception gap in terms of decision-making between headquarters and subsidiaries. We argue that future research needs to carefully consider and account for the perception gap and point out the importance of the role of MNE managers in removing such barriers in order to achieve effective decision-making....
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Black holes in loop quantum gravity.
Perez, Alejandro
2017-12-01
This is a review of results on black hole physics in the context of loop quantum gravity. The key feature underlying these results is the discreteness of geometric quantities at the Planck scale predicted by this approach to quantum gravity. Quantum discreteness follows directly from the canonical quantization prescription when applied to the action of general relativity that is suitable for the coupling of gravity with gauge fields, and especially with fermions. Planckian discreteness and causal considerations provide the basic structure for the understanding of the thermal properties of black holes close to equilibrium. Discreteness also provides a fresh new look at more (at the moment) speculative issues, such as those concerning the fate of information in black hole evaporation. The hypothesis of discreteness leads, also, to interesting phenomenology with possible observational consequences. The theory of loop quantum gravity is a developing program; this review reports its achievements and open questions in a pedagogical manner, with an emphasis on quantum aspects of black hole physics.
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Maternal Child-Rearing Patterns and Children's Scholastic Achievement in Different Groups.
Logan, Richard D.
The purpose of this study was to examine the general proposition that different maternal child-rearing pattern-types (permissive or restrictive) are associated with high scholastic achievement in elementary school children from four different class-culture groupings (black middle-class, black working-class, white middle-class, and white…
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Sumter, Jeremiah, Jr.
2016-01-01
Research and history has demonstrated the overwhelming disparity and gap of mathematical achievement between African Americans and their White counterparts. According to the National Assessment of Educational Progress (NAEP), the achievement gap on a national level is prevalent. The USA jurisdiction has Black 8th grade math students results at 12%…
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Closing the mycetoma knowledge gap.
van de Sande, Wendy; Fahal, Ahmed; Ahmed, Sarah Abdalla; Serrano, Julian Alberto; Bonifaz, Alexandro; Zijlstra, Ed
2018-04-01
On 28th May 2016, mycetoma was recognized as a neglected tropical disease by the World Health Organization. This was the result of a 4-year journey starting in February 2013 with a meeting of global mycetoma experts. Knowledge gaps were identified and included the incidence, prevalence, and mapping of mycetoma; the mode of transmission; the development of methods for early diagnosis; and better treatment. In this review, we review the road to recognition, the ISHAM working group meeting in Argentina, and we address the progress made in closing the knowledge gaps since 2013. Progress included adding another 9000 patients to the literature, which allowed us to update the prevalence map on mycetoma. Furthermore, based on molecular phylogeny, species names were corrected and four novel mycetoma causative agents were identified. By mapping mycetoma causative agents an association with Acacia trees was found. For early diagnosis, three different isothermal amplification techniques were developed, and novel antigens were discovered. To develop better treatment strategies for mycetoma patients, in vitro susceptibility tests for the coelomycete agents of black grain mycetoma were developed, and the first randomized clinical trial for eumycetoma started early 2017.
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International Nuclear Information System (INIS)
Goektepe, G.
2002-01-01
The catastrophic degradation of the Black Sea in a period of four decade has been the major concern of the Black Sea countries and international communities since Bucharest Convention signed in 1992. The Black Sea Region has became a challenging international arena for political scientific and socio-economic activities. Intensive international programmes and establishment of governmental and Non Governmental Organizational structures of the 1990s including Black Sea Economic Cooperation (BSEC), Black Sea Environmental Programme(BSEP), Environmental Programme for the Danube River Basin, Marine Environmental Assessment of the Black Sea Region Technical Cooperation Programme by the IAEA and establishment of the Black Sea Commission Permanent Secretariat are some of the major international efforts of the past decade that emphasizes the multi-nationality and large dimension of the Black Sea environmental management issues. The environmental degradation of the Black Sea is briefly reviewed based on the BSEP reports and data available for land based pollution sources. The environmental risk of marine vessel accidents are indicated and environmental safety concern is emphasized under the current conditions of intense energy transportation projects in the Black Sea and Caspian regions. The international policy actions, co-operation issues and scientific programmes of the past decade are overviewed with emphasis on the international achievements. Concluding remarks include the vital importance of continuation of the international commitments and sharing the political, scientific and socio-economic responsibility on the transboundary environmental pollution, rehabilitation and the safety issues of the Black Sea
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Aerodynamic performance of winglets covering the tip gap inlet in a turbine cascade
Energy Technology Data Exchange (ETDEWEB)
Lee, Sang Woo, E-mail: swlee@kumoh.ac.kr [Department of Mechanical Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Kim, Seon Ung; Kim, Kyoung Hoon [Department of Mechanical Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of)
2012-04-15
Highlights: Black-Right-Pointing-Pointer We test aerodynamics of PS and LEPS winglets for three winglet widths. Black-Right-Pointing-Pointer PS winglet reduces tip leakage loss but increases loss in the passage vortex region. Black-Right-Pointing-Pointer Mass-averaged loss reductions by PS and LEPS winglets are marginal. Black-Right-Pointing-Pointer The loss reductions are much smaller than that by a cavity squealer tip. - Abstract: The aerodynamic performance of two different kinds of winglets covering the tip gap inlet of a plane tip, a 'pressure-side' (PS) winglet and a 'leading-edge and pressure-side' (LEPS) winglet, has been investigated in a turbine cascade. For a tip gap height-to-chord ratio of h/c = 2.0%, their width-to-pitch ratio is changed to be w/p = 2.64, 5.28, and 10.55%. The PS winglet reduces aerodynamic loss in the tip leakage vortex region as well as in an area downstream of the winglet-pressure surface corner, whereas it increases aerodynamic loss in the central area of the passage vortex region. The additional leading-edge winglet portion of the LEPS winglet reduces aerodynamic loss considerably on the casing wall side of the passage vortex region but delivers a noticeable aerodynamic loss increase on its mid-span side. These local trends are deepened with increasing w/p. However, the mass-averaged aerodynamic loss reductions by installing the PS and LEPS winglets in comparison with the baseline no winglet data are only marginal even for w/p = 10.55% and found much smaller than that by employing a cavity squealer tip.
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The Gamma Gap and All-Cause Mortality.
Directory of Open Access Journals (Sweden)
Stephen P Juraschek
Full Text Available The difference between total serum protein and albumin, i.e. the gamma gap, is a frequently used clinical screening measure for both latent infection and malignancy. However, there are no studies defining a positive gamma gap. Further, whether it is an independent risk factor of mortality is unknown.This study examined the association between gamma gap, all-cause mortality, and specific causes of death (cardiovascular, cancer, pulmonary, or other in 12,260 participants of the National Health and Nutrition Examination Survey (NHANES from 1999-2004. Participants had a comprehensive metabolic panel measured, which was linked with vital status data from the National Death Index. Cause of death was based on ICD10 codes from death certificates. Analyses were performed with Cox proportional hazards models adjusted for mortality risk factors. The mean (SE age was 46 (0.3 years and the mean gamma gap was 3.0 (0.01 g/dl. The population was 52% women and 10% black. During a median follow-up period of 4.8 years (IQR: 3.3 to 6.2 years, there were 723 deaths. The unadjusted 5-year cumulative incidences across quartiles of the gamma gap (1.7-2.7, 2.8-3.0, 3.1-3.2, and 3.3-7.9 g/dl were 5.7%, 4.2%, 5.5%, and 7.8%. After adjustment for risk factors, participants with a gamma gap of ≥3.1 g/dl had a 30% higher risk of death compared to participants with a gamma gap <3.1 g/dl (HR: 1.30; 95%CI: 1.08, 1.55; P = 0.006. Gamma gap (per 1.0 g/dl was most strongly associated with death from pulmonary causes (HR 2.22; 95%CI: 1.19, 4.17; P = 0.01.The gamma gap is an independent risk factor for all-cause mortality at values as low as 3.1 g/dl (in contrast to the traditional definition of 4.0 g/dl, and is strongly associated with death from pulmonary causes. Future studies should examine the biologic pathways underlying these associations.
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Closing the Gaps. Research Brief
Johnston, Howard
2011-01-01
Achievement gaps between groups of students (minority and white, rich and poor, English speakers and English language learners) are complex and intractable. Increasingly, they are being seen as a result of disparities between opportunities for learning available to different groups. By changing the opportunity structures of schools and…
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Directory of Open Access Journals (Sweden)
Amadu J. Kaba
2005-04-01
Full Text Available This research argues that despite all of the obstacles that African Americans have confronted in the history of the United States, they have made substantial progress in higher education attainment from the 1970s to the beginning of the 21st century. It reveals that the rise in attainment of college and university degrees has resulted in a substantial increase in living standards and that African Americans are making important economic, social and political contributions to the United States. I present several reasons why black males are not performing as well as black females in higher education attainment. Analyses are also presented regarding the current and future implications of the growing gap between black males and black females.
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Gap Filling of Daily Sea Levels by Artificial Neural Networks
Directory of Open Access Journals (Sweden)
Lyubka Pashova
2013-06-01
Full Text Available In the recent years, intelligent methods as artificial neural networks are successfully applied for data analysis from different fields of the geosciences. One of the encountered practical problems is the availability of gaps in the time series that prevent their comprehensive usage for the scientific and practical purposes. The article briefly describes two types of the artificial neural network (ANN architectures - Feed-Forward Backpropagation (FFBP and recurrent Echo state network (ESN. In some cases, the ANN can be used as an alternative on the traditional methods, to fill in missing values in the time series. We have been conducted several experiments to fill the missing values of daily sea levels spanning a 5-years period using both ANN architectures. A multiple linear regression for the same purpose has been also applied. The sea level data are derived from the records of the tide gauge Burgas, which is located on the western Black Sea coast. The achieved results have shown that the performance of ANN models is better than that of the classical one and they are very promising for the real-time interpolation of missing data in the time series.
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Black holes as mirrors: quantum information in random subsystems
International Nuclear Information System (INIS)
Hayden, Patrick; Preskill, John
2007-01-01
We study information retrieval from evaporating black holes, assuming that the internal dynamics of a black hole is unitary and rapidly mixing, and assuming that the retriever has unlimited control over the emitted Hawking radiation. If the evaporation of the black hole has already proceeded past the ''half-way'' point, where half of the initial entropy has been radiated away, then additional quantum information deposited in the black hole is revealed in the Hawking radiation very rapidly. Information deposited prior to the half-way point remains concealed until the half-way point, and then emerges quickly. These conclusions hold because typical local quantum circuits are efficient encoders for quantum error-correcting codes that nearly achieve the capacity of the quantum erasure channel. Our estimate of a black hole's information retention time, based on speculative dynamical assumptions, is just barely compatible with the black hole complementarity hypothesis
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Quantifying yield gaps in wheat production in Russia
International Nuclear Information System (INIS)
Schierhorn, Florian; Prishchepov, Alexander V; Koch, Friedrich J; Müller, Daniel; Faramarzi, Monireh
2014-01-01
Crop yields must increase substantially to meet the increasing demands for agricultural products. Crop yield increases are particularly important for Russia because low crop yields prevail across Russia’s widespread and fertile land resources. However, reliable data are lacking regarding the spatial distribution of potential yields in Russia, which can be used to determine yield gaps. We used a crop growth model to determine the yield potentials and yield gaps of winter and spring wheat at the provincial level across European Russia. We modeled the annual yield potentials from 1995 to 2006 with optimal nitrogen supplies for both rainfed and irrigated conditions. Overall, the results suggest yield gaps of 1.51–2.10 t ha −1 , or 44–52% of the yield potential under rainfed conditions. Under irrigated conditions, yield gaps of 3.14–3.30 t ha −1 , or 62–63% of the yield potential, were observed. However, recurring droughts cause large fluctuations in yield potentials under rainfed conditions, even when the nitrogen supply is optimal, particularly in the highly fertile black soil areas of southern European Russia. The highest yield gaps (up to 4 t ha −1 ) under irrigated conditions were detected in the steppe areas in southeastern European Russia along the border of Kazakhstan. Improving the nutrient and water supply and using crop breeds that are adapted to the frequent drought conditions are important for reducing yield gaps in European Russia. Our regional assessment helps inform policy and agricultural investors and prioritize research that aims to increase crop production in this important region for global agricultural markets. (letter)
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Looking for the invisible universe - Black matter, black energy, black holes
International Nuclear Information System (INIS)
Elbaz, David
2016-01-01
As the discovery of the expansion of the universe and of black holes put the study of cosmology into question again because it now refers to invisible things such as black holes, black energy and black matter, the author proposes an other view on the universe within such a context. He first discusses these three enigmas of black matter, black energy and black holes. In a second part, he addresses, discusses and comments five illusions: the Uranian illusion (questions of the existence of an anti-world, of black matter temperature), the Mercurian illusion (quantum gravity, the string theory), the Martian illusion (a patchwork universe, the illusion of the infinite), the cosmic Maya (the John Wheeler's cup, the holographic universe), and the narcissistic illusion
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Recent Trends in Income, Racial, and Ethnic School Readiness Gaps at Kindergarten Entry
Directory of Open Access Journals (Sweden)
Sean F. Reardon
2016-07-01
Full Text Available Academic achievement gaps between high- and low-income students born in the 1990s were much larger than between cohorts born two decades earlier. Racial/ethnic achievement gaps declined during the same period. To determine whether these two trends have continued in more recent cohorts, we examine trends in several dimensions of school readiness, including academic achievement, self-control, externalizing behavior, and a measure of students’ approaches to learning, for cohorts born from the early 1990s to the 2000–2010 midperiod. We use data from nationally representative samples of kindergarteners (ages 5–6 in 1998 ( n = 20,220, 2006 ( n = 6,600, and 2010 ( n = 16,980 to estimate trends in racial/ethnic and income school readiness gaps. We find that readiness gaps narrowed modestly from 1998 to 2010, particularly between high- and low-income students and between White and Hispanic students.
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Formulation and properties of ADN/GAP propellants
Energy Technology Data Exchange (ETDEWEB)
Menke, Klaus; Heintz, Thomas; Schweikert, Wenka; Keicher, Thomas; Krause, Horst [Fraunhofer-Institut fuer Chemische Technologie ICT, Pfinztal (Germany)
2009-06-15
In this contribution two ways are described, how it is possible to achieve perfectly cured and processible propellants with prilled ADN, low amounts of HMX 5{mu}m mps and a binder system based on GAP diole and GAP triole oligomers with and without TMETN as a nitrate ester plasticizer. It was shown how it will be possible to suppress the strongly gas forming reaction between ADN and reactive isocyanates by a mixture of stabilizers. In this way it was possible to create minimum smoke ADN/HMX/GAP/TMETN propellants cured with the triisocyanate N100. In the second part an unconventional binder system based on the 1.3 dipolar cycloaddition reaction of azido groups with acetylene compounds forming 1,2,3-triazole heterocyclic rings has been applied for ADN/GAP and AP/GAP propellants. Together with small parts of HMX formulations with ADN/HMX/GAP and the corresponding AP/HMX/GAP exhibit high thermodynamic performance, are easily processible, and cure successfully at 60 C. Their basic properties consisting of burning behavior and mechanical properties, at ambient temperature, chemical stability, and sensitivity have been investigated and are compared to each other. (Abstract Copyright [2009], Wiley Periodicals, Inc.)
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Black males' self-perceptions of academic ability and gifted potential in advanced science classes
Rascoe, Barbara; Monroe Atwater, Mary
2005-10-01
The purpose of this research effort was to examine Black male students' self-perceptions of academic ability and gifted potential in science. The purposeful sample consisted of nine Black males between the ages of 14 and 18 years. Four categories of self-perceptions of academic ability and gifted potential emerged from the data. These included: (a) gifted high achievers; (b) gifted could do better high achievers; (c) gifted could do better situational nonachievers; and (d) gifted could do better underachievers. Science teachers' influences that referenced participants' academic achievement pointed to validation. Participants' perceptions regarding how science teachers' influenced their academic performance focused on science teachers' content knowledge. Power dynamics germane to Black male participants' value or worth that directed their efforts in science learning environments are discussed. Implications are posited for science teaching, science education programs, and future research. This research endeavor was based on two premises. The first premise is that Black males' self-perceptions of academic ability affect their science academic achievement. The second premise is that, given parental, peer, and community influences, science teachers have considerable influence on students' self-perceptions of academic ability. However, the focus of this research was not on parental influences, peer influences, or any potential influences that participants' communities may have on their academic achievement.
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Asthma and the Achievement Gap among Urban Minority Youth
Basch, Charles E.
2011-01-01
Objectives: To outline the prevalence and disparities of asthma among school-aged urban minority youth, causal pathways through which poorly controlled asthma adversely affects academic achievement, and proven or promising approaches for schools to address these problems. Methods: Literature review. Results: Asthma is the most common chronic…
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Black hole based quantum computing in labs and in the sky
Energy Technology Data Exchange (ETDEWEB)
Dvali, Gia [Arnold Sommerfeld Center for Theoretical Physics, Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY (United States); Panchenko, Mischa [Arnold Sommerfeld Center for Theoretical Physics, Department fuer Physik, Ludwig-Maximilians-Universitaet Muenchen (Germany)
2016-08-15
Analyzing some well established facts, we give a model-independent parameterization of black hole quantum computing in terms of a set of macro and micro quantities and their relations. These include the relations between the extraordinarily-small energy gap of black hole qubits and important time-scales of information-processing, such as, scrambling time and Page's time. We then show, confirming and extending previous results, that other systems of nature with identical quantum informatics features are attractive Bose-Einstein systems at the critical point of quantum phase transition. Here we establish a complete isomorphy between the quantum computational properties of these two systems. In particular, we show that the quantum hair of a critical condensate is strikingly similar to the quantum hair of a black hole. Irrespectively whether one takes the similarity between the two systems as a remarkable coincidence or as a sign of a deeper underlying connection, the following is evident. Black holes are not unique in their way of quantum information processing and we can manufacture black hole based quantum computers in labs by taking advantage of quantum criticality. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Black hole based quantum computing in labs and in the sky
International Nuclear Information System (INIS)
Dvali, Gia; Panchenko, Mischa
2016-01-01
Analyzing some well established facts, we give a model-independent parameterization of black hole quantum computing in terms of a set of macro and micro quantities and their relations. These include the relations between the extraordinarily-small energy gap of black hole qubits and important time-scales of information-processing, such as, scrambling time and Page's time. We then show, confirming and extending previous results, that other systems of nature with identical quantum informatics features are attractive Bose-Einstein systems at the critical point of quantum phase transition. Here we establish a complete isomorphy between the quantum computational properties of these two systems. In particular, we show that the quantum hair of a critical condensate is strikingly similar to the quantum hair of a black hole. Irrespectively whether one takes the similarity between the two systems as a remarkable coincidence or as a sign of a deeper underlying connection, the following is evident. Black holes are not unique in their way of quantum information processing and we can manufacture black hole based quantum computers in labs by taking advantage of quantum criticality. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Configurational entropy of anti-de Sitter black holes
International Nuclear Information System (INIS)
Braga, Nelson R.F.; Rocha, Roldão da
2017-01-01
Recent studies indicate that the configurational entropy is an useful tool to investigate the stability and (or) the relative dominance of states for diverse physical systems. Recent examples comprise the connection between the variation of this quantity and the relative fraction of light mesons and glueballs observed in hadronic processes. Here we develop a technique for defining a configurational entropy for an AdS-Schwarzschild black hole. The achieved result corroborates consistency with the Hawking–Page phase transition. Namely, the dominance of the black hole configurational entropy will be shown to increase with the temperature. In order to verify the consistency of the new procedure developed here, we also consider the case of black holes in flat space-time. For such a black hole, it is known that evaporation leads to instability. The configurational entropy obtained for the flat space case is thoroughly consistent with the physical expectation. In fact, we show that the smaller the black holes, the more unstable they are. So, the configurational entropy furnishes a reliable measure for stability of black holes.
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Configurational entropy of anti-de Sitter black holes
Energy Technology Data Exchange (ETDEWEB)
Braga, Nelson R.F., E-mail: braga@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RJ 21941-972 (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC – UFABC, 09210-580, Santo André (Brazil)
2017-04-10
Recent studies indicate that the configurational entropy is an useful tool to investigate the stability and (or) the relative dominance of states for diverse physical systems. Recent examples comprise the connection between the variation of this quantity and the relative fraction of light mesons and glueballs observed in hadronic processes. Here we develop a technique for defining a configurational entropy for an AdS-Schwarzschild black hole. The achieved result corroborates consistency with the Hawking–Page phase transition. Namely, the dominance of the black hole configurational entropy will be shown to increase with the temperature. In order to verify the consistency of the new procedure developed here, we also consider the case of black holes in flat space-time. For such a black hole, it is known that evaporation leads to instability. The configurational entropy obtained for the flat space case is thoroughly consistent with the physical expectation. In fact, we show that the smaller the black holes, the more unstable they are. So, the configurational entropy furnishes a reliable measure for stability of black holes.
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Dark matter influence on black objects thermodynamics
Rogatko, Marek; Wojnar, Aneta
2018-05-01
Physical process version of the first law of black hole thermodynamics in Einstein-Maxwell dark matter gravity was derived. The dark matter sector is mimicked by the additional U(1)-gauge field coupled to the ordinary Maxwell one. By considering any cross section of the black hole event horizon to the future of the bifurcation surface, the equilibrium state version of the first law of black hole mechanics was achieved. The considerations were generalized to the case of Einstein-Yang-Mills dark matter gravity theory. The main conclusion is that the influence of dark matter is crucial in the formation process of black objects. This fact may constitute the explanation of the recent observations of the enormous mass of the super luminous quasars formed in a relatively short time after Big Bang. We also pay attention to the compact binaries thermodynamics, when dark matter sector enters the game.
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Full-waveform inversion: Filling the gaps
Beydoun, Wafik B.; Alkhalifah, Tariq Ali
2015-01-01
After receiving an outstanding response to its inaugural workshop in 2013, SEG once again achieved great success with its 2015 SEG Middle East Workshop, “Full-waveform inversion: Filling the gaps,” which took place 30 March–1 April 2015 in Abu Dhabi
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The Crisis in Black and Black.
Hutchinson, Earl Ofari
These essays explore why the historic conflict between blacks and whites in the United States has become a crisis that divides many African Americans. The changing racial dynamic is not marked by conflicts. between the black middle class and the poor, black men and women, the black intellectual elite and rappers, black politicians and the urban…
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Black GE based on crystalline/amorphous core/shell nanoneedle arrays
Javey, Ali; Chueh, Yu-Lun; Fan, Zhiyong
2014-03-04
Direct growth of black Ge on low-temperature substrates, including plastics and rubber is reported. The material is based on highly dense, crystalline/amorphous core/shell Ge nanoneedle arrays with ultrasharp tips (.about.4 nm) enabled by the Ni catalyzed vapor-solid-solid growth process. Ge nanoneedle arrays exhibit remarkable optical properties. Specifically, minimal optical reflectance (<1%) is observed, even for high angles of incidence (.about.75.degree.) and for relatively short nanoneedle lengths (.about.1 .mu.m). Furthermore, the material exhibits high optical absorption efficiency with an effective band gap of .about.1 eV. The reported black Ge can have important practical implications for efficient photovoltaic and photodetector applications on nonconventional substrates.
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Royle, Jonathan
2013-01-01
The consistent underperformance of African American students casts a disparaging shadow on the success of American public schools. Research was necessary to understand the reason for such a difference in scores. Parents, teachers, and administrators must understand the reason for the gap in order to determine the strategies and support systems…
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The Achievement Gap between Science Classrooms and Historic Inequalities
Howie, Sarah; Scherman, Vanessa
2008-01-01
In the past politics deprived many African children (in particular) in South Africa the opportunity of achieving quality education. This was most especially true in subjects such as mathematics and science. In this research the science teacher-level data from Third International Mathematics and Science Study 1999 (TIMSS'99) were analysed with a…
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Interaction of the Bragg gap with polaritonic gap in opal photonic crystals
Nayer, Eradat; Sivachenko, Andrey Yu; Li, Sergey; Raikh, Mikhail E.; Valy Vardeny, Z.
2001-03-01
Photonic crystals (PC) are a class of artificial structures with a periodic dielectric function. PCs can be a laboratory for testing fundamental processes involving interactions of radiation with matter in novel conditions. We have studied the optical properties of opal PCs that are infiltrated with highly polarizable media such as j-aggregates of cyanine dyes. Opals are self- assembled structures of silica (SiO_2) spheres. We report our studies on clarifying the relationship between a polaritonic gap and a photonic stop band (Bragg gap) when they resonantly coexist in the same structure. Infiltration of opal with polarizable molecules combines the polaritonic and Bragg diffractive effects. Both effects exist independently when the Bragg (at ω=ω_B) and polaritonic (at ω=ω_T) resonances are well separated in frequency. A completely different situation occurs when ωT =ω_B. Such a condition was achieved in opals that were infiltrated with J-aggregates of cyanine dyes that have large Rabi frequency. Our measurements show some dramatic changes in the shape of the reflectivity plateaus, which are due to the interplay between the photonic band gap and the polaritonic gap. The experimental results on reflectivity and its dependence on the light propagation angle and concentration of the cyanie dyes are in agreement with the theoretical calculations. (The work was supported in part by Army Research office DAAD19-00-1-0406.)
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Black Sea Energy Security - Present and Future
Directory of Open Access Journals (Sweden)
Florinel Iftode
2011-05-01
Full Text Available We chose this theme to highlight the need for continuous and sustained human society to secure energy resources needed to survive, needs reflected in an increasingly in recent years in the strategies adopted at both states, as at the level of international organizations. Achieving security and stability in the wider Black Sea area has been among the priorities of each country's interests in this region. In this context, state and non-state actors were being called to come up with new solutions to achieve those interests. Certainly not in all cases the negotiations were completed or not yet found a generally accepted formula for others to apply, but most of them show off their values. The main environmental threats to security environment in the Black Sea region are represented by ethnic conflicts and territorial secessionism. A significant contribution to the security environment of the Black Sea region has the phenomenon of globalization, which in this region is manifested by a steady increase in traffic and volume of shipping passage of communication, which largely affects the security in the region. Globalization and the need for energy resources in the Black Sea was an important area not only as energy transport route, but as a potential supplier of material energy (oil and natural gas. Black Sea Basin can be stabilized and secured only by the will and input from all States and interested international organizations in pragmatic and effective institutional frameworks, meant to promote and protect the common interests of countries decided to participate in actions aimed at ensuring a stable environment security.
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Gender Gap or Program Gap? Students' Negotiations of Study Practice in a Course in Electromagnetism
Andersson, Staffan; Johansson, Anders
2016-01-01
This study of achievement differences, as reflected by course grades, on a third-semester electromagnetism course at a Swedish research university was motivated by instructor concerns about gender inequalities. Quantitative analysis showed a gender gap in course grades between female and male students for the period of fall 2007 to spring 2013.…
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Rodriguez, Carl L; Amaro-Seoane, Pau; Chatterjee, Sourav; Rasio, Frederic A
2018-04-13
We present models of realistic globular clusters with post-Newtonian dynamics for black holes. By modeling the relativistic accelerations and gravitational-wave emission in isolated binaries and during three- and four-body encounters, we find that nearly half of all binary black hole mergers occur inside the cluster, with about 10% of those mergers entering the LIGO/Virgo band with eccentricities greater than 0.1. In-cluster mergers lead to the birth of a second generation of black holes with larger masses and high spins, which, depending on the black hole natal spins, can sometimes be retained in the cluster and merge again. As a result, globular clusters can produce merging binaries with detectable spins regardless of the birth spins of black holes formed from massive stars. These second-generation black holes would also populate any upper mass gap created by pair-instability supernovae.
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Rodriguez, Carl L.; Amaro-Seoane, Pau; Chatterjee, Sourav; Rasio, Frederic A.
2018-04-01
We present models of realistic globular clusters with post-Newtonian dynamics for black holes. By modeling the relativistic accelerations and gravitational-wave emission in isolated binaries and during three- and four-body encounters, we find that nearly half of all binary black hole mergers occur inside the cluster, with about 10% of those mergers entering the LIGO/Virgo band with eccentricities greater than 0.1. In-cluster mergers lead to the birth of a second generation of black holes with larger masses and high spins, which, depending on the black hole natal spins, can sometimes be retained in the cluster and merge again. As a result, globular clusters can produce merging binaries with detectable spins regardless of the birth spins of black holes formed from massive stars. These second-generation black holes would also populate any upper mass gap created by pair-instability supernovae.
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Surface-enhanced Raman scattering sensing on black silicon
International Nuclear Information System (INIS)
Gervinskas, Gediminas; Seniutinas, Gediminas; Hartley, Jennifer S.; Stoddart, Paul R.; Juodkazis, Saulius; Kandasamy, Sasikaran; Fahim, Narges F.
2013-01-01
Reactive ion etching was used to fabricate black-Si over the entire surface area of 4-inch Si wafers. After 20 min of the plasma treatment, surface reflection well below 2% was achieved over the 300-1000 nm spectral range. The spikes of the black-Si substrates were coated by gold, resulting in an island film for surface-enhanced Raman scattering (SERS) sensing. A detection limit of 1 x 10 -6 M (at count rate > 10 2 s -1 . mW -1 ) was achieved for rhodamine 6G in aqueous solution when drop cast onto a ∝ 100-nm-thick Au coating. The sensitivity increases for thicker coatings. A mixed mobile-on-immobile platform for SERS sensing is introduced by using dog-bone Au nanoparticles on the Au/black-Si substrate. The SERS intensity shows a non-linear dependence on the solid angle (numerical aperture of excitation/collection optics) for a thick gold coating that exhibits a 10 times higher enhancement. This shows promise for augmented sensitivity in SERS applications. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Lee, Courtland C.
This series of five interrelated modules is an update and revision of "Saving the Native Son: Empowerment Strategies for Young Black Males (1996)." It offers specific strategies for empowering young African American males to help them achieve optimal educational and social success. Empowerment is a developmental process by which people who are…
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Energy Technology Data Exchange (ETDEWEB)
NONE
2002-02-01
instance, the UK's research councils have yet to put any real money behind these ideas. Black holes are best described by the general theory of relativity. However, general relativity is a classical theory of gravity, and although its predictions have been verified in many experiments, a quantum theory of gravity remains one of the holy grails of physics. One of the first physicists to make real progress in this quest to reconcile general relativity and quantum mechanics was Stephen Hawking. In 1974 Hawking calculated what would happen if a quantum fluctuation occurred near an event horizon. He concluded that the black hole would radiate, and that the amount of radiation would be inversely proportional to the mass of the black hole. However, black holes tend to be very heavy, so their output of Hawking radiation would be too low to detect experimentally. One intriguing exception could be much smaller primordial black holes created in the big bang: these should radiate observable amounts of gamma rays, but they have not been detected yet. This whole body of work - in which thermodynamic concepts such as temperature and entropy are also associated with the black hole - is Hawking's major achievement in physics. The detection of Hawking radiation is the ultimate goal of experiments on artificial black holes, although a lot of theoretical and experimental work has to be done first. The successful experiment is likely to involve a flowing Bose-Einstein condensate or a medium in which the speed of light can be reduced to zero. After years of groundwork, physicists have recently made rapid progress in both these fields. Meanwhile, the recent observation of neutrons in discrete quantum states in a gravitational potential shows that quantum gravity effects can be seen in the laboratory. All that is needed now is an act of faith. (U.K.)
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The gender gap reloaded: are school characteristics linked to labor market performance?
Konstantopoulos, Spyros; Constant, Amelie
2008-06-01
This study examines the wage gender gap of young adults in the 1970s, 1980s, and 2000 in the US. Using quantile regression we estimate the gender gap across the entire wage distribution. We also study the importance of high school characteristics in predicting future labor market performance. We conduct analyses for three major racial/ethnic groups in the US: Whites, Blacks, and Hispanics, employing data from two rich longitudinal studies: NLS and NELS. Our results indicate that while some school characteristics are positive and significant predictors of future wages for Whites, they are less so for the two minority groups. We find significant wage gender disparities favoring men across all three surveys in the 1970s, 1980s, and 2000. The wage gender gap is more pronounced in higher paid jobs (90th quantile) for all groups, indicating the presence of a persistent and alarming "glass ceiling."
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Boen, Courtney
2016-12-01
Research links Black-White health disparities to racial differences in socioeconomic status (SES), but understanding of the role of SES in racial health gaps has been restricted by reliance on static measures of health and socioeconomic well-being that mask the dynamic quality of these processes and ignore the racialized nature of the SES-health connection. Utilizing twenty-three years of longitudinal data from the Panel Study of Income Dynamics (1984-2007), this study uses multilevel growth curve models to examine how multiple dimensions of socioeconomic well-being-including long-term economic history and differential returns to SES-contribute to the life course patterning of Black-White health disparities across two critical markers of well-being: body mass index (N = 9057) and self-rated health (N = 11,329). Findings indicate that long-term SES exerts a significant influence on both body mass index and self-rated health, net of point-in-time measures, and that Black-White health gaps are smallest in models that adjust for both long-term and current SES. I also find that Blacks and Whites receive differential health returns to increases in SES, which suggests that other factors-such as neighborhood segregation and exposure racial discrimination-may restrict Blacks from converting increases in SES into health improvements in the same way as Whites. Together, these processes contribute to the life course patterning of Black-White health gaps and raise concerns about previous misestimation of the role of SES in racial health disparities. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Ridgeway, Monica Lynn
As a critical race ethnography, this dissertation attempts to foreground the richness of Black urban youth culture during and around science classroom instruction. Ironically, during an era of much diversity rhetoric in the United States, the culture of urban Black youth is rarely reflected in mainstream public school culture. I attempt to explicate such a worldview compassionately and authentically for both insiders and outsiders of the lived experiences of Black America. Education in the United States can be damning for Black youth who do not fit the mainstream mold, and several authors have provided detailed critique of mechanisms that shape, direct, and marginalize outliers to the successful academic cultural model. The U.S. through this lens is experiencing an opportunity gap, not an achievement gap--one which equitable educational experience can best be viewed through the richness of critical ethnographic methods. This methodical approach allowed me as a researcher to listen to marginalized voices and to incorporate lived interactions with youth, their parents, and community stakeholders all committed to provide support for the today's youth. As a Black female science educator, I explore the evidence for reform impact as I examine in school experiences and science teaching of culturally relevant pedagogies for urban, working-class and poor families of color in grades six-eight who participated in a Western New York academic enrichment program. Findings suggest that skepticism of reform efforts and new pedagogical approaches existed for all stakeholders aforementioned, but that students were the most amenable and responsive to alternative educational approaches. Specific recommendations for engaging students in inquiry processes are given for teachers, institutions, parents and students on the basis of videotaped lessons, interviews, and instructional artifacts. Implications include the recommendations that educators working with youth of color need to be
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Black Sea Governorate during World War I: A Historiographical Survey
Directory of Open Access Journals (Sweden)
Lyubov G. Polyakova
2015-06-01
Full Text Available This survey article addresses the historiography of World War I in the territory of Black Sea Governorate. The author singles out three chronological periods, ante-revolutionary, Soviet, and present-day Russian, and discusses distinctive characteristics in the study of the history of each of the periods. Thus, for instance, a distinctive trait in the study of World War I during the Soviet period was a permanent search in it for preconditions for the socialist revolution, which led to the artificial politicization of events and phenomena. The author comes to the conclusion that the historiography of World War I in the territory of Black Sea Governorate has considerable gaps, while the topic itself is yet to become the subject of comprehensive study. Up until the present day the following topics have remained virtually unstudied: the activity of the hospital framework across Black Sea Governorate, the identification of distinctive characteristics of combating alcoholism during the war, and the activity of charity societies.
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Accretion onto a noncommutative geometry inspired black hole
Energy Technology Data Exchange (ETDEWEB)
Kumar, Rahul [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); Jamia Millia Islamia, Multidisciplinary Centre for Advanced Research and Studies (MCARS), New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Durban (South Africa)
2017-09-15
The spherically symmetric accretion onto a noncommutative (NC) inspired Schwarzschild black hole is treated for a polytropic fluid. The critical accretion rate M, sonic speed a{sub s} and other flow parameters are generalized for the NC inspired static black hole and compared with the results obtained for the standard Schwarzschild black holes. Also explicit expressions for gas compression ratios and temperature profiles below the accretion radius and at the event horizon are derived. This analysis is a generalization of Michel's solution to the NC geometry. Owing to the NC corrected black hole, the accretion flow parameters also have been modified. It turns out that M ∼ M{sup 2} is still achievable but r{sub s} seems to be substantially decreased due to the NC effects. They in turn do affect the accretion process. (orig.)
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What Works Clearinghouse, 2014
2014-01-01
For the 2014 study, "Closing the Social-Class Achievement Gap: A Difference-Education Intervention Improves First-Generation Students' Academic Performance and All Students' College Transition," researchers investigated the impact of attending a moderated panel on incoming freshmen's adjustment to college. The panel featured…
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Lessons from a Black Woman Administrator: "I'm Still Here"
Dowdy, Joanne Kilgour; Hamilton, Awilda
2012-01-01
This case study presents the findings from a qualitative research project about a Black woman scholar, the first non-White female to serve as chair of a department and the associate dean of the college in its 100 year history. The study focuses on the experiences of a Black woman scholar as a chairperson and the learning she achieved during her…
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Holographic fermionic spectrum from Born–Infeld AdS black hole
Directory of Open Access Journals (Sweden)
Jian-Pin Wu
2016-07-01
Full Text Available In this letter, we systematically explore the holographic (non-relativistic fermionic spectrum without/with dipole coupling dual to Born–Infeld anti-de Sitter (BI-AdS black hole. For the relativistic fermionic fixed point, this holographic fermionic system exhibits non-Fermi liquid behavior. Also, with the increase of BI parameter γ, the non-Fermi liquid becomes even “more non-Fermi”. When the dipole coupling term is included, we find that the BI term makes it a lot tougher to form the gap. While for the non-relativistic fermionic system with large dipole coupling in BI-AdS background, with the increase of BI parameter, the gap comes into being again.
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Flat-space holography and stress tensor of Kerr black hole
Energy Technology Data Exchange (ETDEWEB)
Baghchesaraei, Omid, E-mail: omidbaghchesaraei@gmail.com [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Fareghbal, Reza, E-mail: r_fareghbal@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Izadi, Yousef, E-mail: yizadi2015@fau.edu [Department of Physics, Florida Atlantic University, Boca Raton, FL 33431 (United States)
2016-09-10
We propose a stress tensor for the Kerr black hole written in the Boyer–Lindquist coordinate. To achieve this, we use the dictionary of the Flat/CCFT correspondence and take the flat-space limit from the quasi-local stress tensor of the four-dimensional Kerr–AdS black hole. The proposed stress tensor yields the correct values for the mass and angular momentum of the Kerr black hole at spatial infinity. We also calculate some components of the energy momentum tensor of the three dimensional CCFT and show that they are consistent with the holographic calculation of the Kerr black hole. The calculation we present in this paper is another confirmation for the Flat/CCFT proposal.
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Higher cardiovascular disease prevalence and mortality among younger blacks compared to whites.
Jolly, Stacey; Vittinghoff, Eric; Chattopadhyay, Arpita; Bibbins-Domingo, Kirsten
2010-09-01
Blacks have higher rates of cardiovascular disease than whites. The age at which these differential rates emerge has not been fully examined. We examined cardiovascular disease prevalence and mortality among black and white adults across the adult age spectrum and explored potential mediators of these differential disease prevalence rates. We conducted a cross-sectional analysis of National Health and Nutrition Examination Survey data from 1999-2006. We estimated age-adjusted and age-specific prevalence ratios (PR) for cardiovascular disease (heart failure, stroke, or myocardial infarction) for blacks versus whites in adults aged 35 years and older and examined potential explanatory factors. From the National Compressed Mortality File 5-year aggregate file of 1999-2003, we determined age-specific cardiovascular disease mortality rates. In young adulthood, cardiovascular disease prevalence was higher in blacks than whites (35-44 years PR 1.9; 95% confidence interval [CI], 1.1-3.4). The black-white PR decreased with each decade of advancing age (P for trend=.04), leading to a narrowing of the racial gap at older ages (65-74 years PR 1.2; 95% CI, 0.8-1.6; > or =75 years PR 1.0; 95% CI, 0.7-1.4). Clinical and socioeconomic factors mediated some, but not all, of the excess cardiovascular disease prevalence among young to middle-aged blacks. Over a quarter (28%) of all cardiovascular disease deaths among blacks occurred in those aged <65 years, compared with 13% among whites. Reducing black/white disparities in cardiovascular disease will require a focus on young and middle-aged blacks.
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First law of black ring thermodynamics in higher dimensional Chern-Simons gravity
International Nuclear Information System (INIS)
Rogatko, Marek
2007-01-01
The physical process version and the equilibrium state version of the first law of black ring thermodynamics in n-dimensional Einstein gravity with Chern-Simons term were derived. This theory constitutes the simplest generalization of the five-dimensional one admitting a stationary black ring solution. The equilibrium state version of the first law of black ring mechanics was achieved by choosing any cross section of the event horizon to the future of the bifurcation surface
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Band Gap Modulated by Electronic Superlattice in Blue Phosphorene.
Zhuang, Jincheng; Liu, Chen; Gao, Qian; Liu, Yani; Feng, Haifeng; Xu, Xun; Wang, Jiaou; Zhao, Jijun; Dou, Shi Xue; Hu, Zhenpeng; Du, Yi
2018-05-22
Exploring stable two-dimensional materials with appropriate band gaps and high carrier mobility is highly desirable due to the potential applications in optoelectronic devices. Here, the electronic structures of phosphorene on a Au(111) substrate are investigated by scanning tunneling spectroscopy, angle-resolved photoemission spectroscopy (ARPES), and density functional theory (DFT) calculations. The substrate-induced phosphorene superstructure gives a superlattice potential, leading to a strong band folding effect of the sp band of Au(111) on the band structure. The band gap could be clearly identified in the ARPES results after examining the folded sp band. The value of the energy gap (∼1.1 eV) and the high charge carrier mobility comparable to that of black phosphorus, which is engineered by the tensile strain, are revealed by the combination of ARPES results and DFT calculations. Furthermore, the phosphorene layer on the Au(111) surface displays high surface inertness, leading to the absence of multilayer phosphorene. All these results suggest that the phosphorene on Au(111) could be a promising candidate, not only for fundamental research but also for nanoelectronic and optoelectronic applications.
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Retinal detachment in black South Africans
African Journals Online (AJOL)
low incidence of retinal detachment in black patients is not known. ... a retinal break. Predisposing factors include peripheral retinal degenerations, myopia, aphakia and trauma. Delay in presentation increases the difficulty in achieving adequate surgical ... On examination, note was taken of the visual acuity in both eyes, the ...
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BOOK REVIEW: Introduction to Black Hole Physics Introduction to Black Hole Physics
Tanaka, Takahiro
2012-07-01
expected in the near future. Such hot topics are presented in Section 10: 'Black Holes and All That Jazz'. I would also consider the historical overview of the research on black holes given in Section 1 to be very interesting. Overall, I strongly recognised the intention of the authors not to go into too much detail; in this sense, I would say that the book has the aspect of a showcase of the frontiers of black hole physics. There are many topics which are very interesting but mathematically a little complicated; however, those subjects are appropriately treated so that the reader will not be overloaded with mathematical complexity. For example, in the discussion of black hole perturbation, only scalar field perturbation is discussed. The authors might have discussed gravitational wave perturbation, but this is much more complicated and the essential physics is mostly included in the simplest example of the scalar field. If I were one of the authors, I would consider adding more detailed explanations about several such advanced topics. However, the authors well know that such a challenge just presents a barrier to young students who are going to read this book, and really it is only an introduction to this interesting research field. This style might be the result of the long experience from the lectures over 30 years: the explanations of the subjects that the authors describe in detail are very carefully presented, avoiding logical gaps. In the preface, the authors state that they tried hard to answer students' questions as much as possible; I think that the authors' method in this respect is very successful.
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Inequality in education and quotas for black students in universities
Directory of Open Access Journals (Sweden)
Eunice R. Durham
Full Text Available This article discusses the proposed definition of quotas for black students in universities in view of the widespread inequalities in the Brazilian educational system. The author defends that the proposed measure would lead to limitations and distortions, for it is based on rigid, artificial categories, in sharp contrast with the country's ethnic heterogeneity, and fails to consider key factors in the schooling experience of afro-descendants. The study of statistical series has shown that in spite of the progress made, there is still a great educational gap dividing white students from black and mulatto students. This led the author to conclude that public initiatives geared to reinforcing basic skills would constitute a more effective affirmative action than the establishment of quotas.
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Blum, Susan D.
2017-01-01
Claiming to rely on "science," many well-intentioned "experts" offer advice on how to "close the gap"--word gap, language gap, achievement gap--between disadvantaged and advantaged children. Based on both research and personal experience, this advice promises magic solutions to apparently complex and intractable…
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MIGRATION TRAPS IN DISKS AROUND SUPERMASSIVE BLACK HOLES
International Nuclear Information System (INIS)
Bellovary, Jillian M.; Low, Mordecai-Mark Mac; McKernan, Barry; Ford, K. E. Saavik
2016-01-01
Accretion disks around supermassive black holes (SMBHs) in active galactic nuclei (AGNs) contain stars, stellar mass black holes, and other stellar remnants, which perturb the disk gas gravitationally. The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks. We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients, applied to two different analytic, steady-state disk models of SMBH accretion disks. We find that there are radii in such disks where the gas torque changes sign, trapping migrating objects. Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative, around 20–300R g , where R g = 2GM/c 2 is the Schwarzschild radius. At these traps, massive objects in the AGN disk can accumulate, collide, scatter, and accrete. Intermediate mass black hole formation is likely in these disk locations, which may lead to preferential gap and cavity creation at these radii. Our model thus has significant implications for SMBH growth as well as gravitational wave source populations
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Congress of the U.S., Washington, DC. House Committee on Education and the Workforce.
A field hearing of the United States House of Representatives' Committee on Education and the Workforce, entitled "Closing the Achievement Gap by Improving Reading Instruction," was held at Lancaster Elementary School in Orlando, Florida, on November 13, 2001. The hearing begins with welcoming statements by the committee chairman and one…
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International Nuclear Information System (INIS)
Boslough, J.
1985-01-01
This book is about the life and work of Stephen Hawking. It traces the development of his theories about the universe and particularly black holes, in a biographical context. Hawking's lecture 'Is the end in sight for theoretical physics' is presented as an appendix. In this, he discusses the possibility of achieving a complete, consistent and unified theory of the physical interactions which would describe all possible observations. (U.K.)
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Impact of Bayesian Priors on the Characterization of Binary Black Hole Coalescences.
Vitale, Salvatore; Gerosa, Davide; Haster, Carl-Johan; Chatziioannou, Katerina; Zimmerman, Aaron
2017-12-22
In a regime where data are only mildly informative, prior choices can play a significant role in Bayesian statistical inference, potentially affecting the inferred physics. We show this is indeed the case for some of the parameters inferred from current gravitational-wave measurements of binary black hole coalescences. We reanalyze the first detections performed by the twin LIGO interferometers using alternative (and astrophysically motivated) prior assumptions. We find different prior distributions can introduce deviations in the resulting posteriors that impact the physical interpretation of these systems. For instance, (i) limits on the 90% credible interval on the effective black hole spin χ_{eff} are subject to variations of ∼10% if a prior with black hole spins mostly aligned to the binary's angular momentum is considered instead of the standard choice of isotropic spin directions, and (ii) under priors motivated by the initial stellar mass function, we infer tighter constraints on the black hole masses, and in particular, we find no support for any of the inferred masses within the putative mass gap M≲5 M_{⊙}.
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Directory of Open Access Journals (Sweden)
Amin Dehyadegari
2017-05-01
Full Text Available It has been argued that charged Anti-de Sitter (AdS black holes have similar thermodynamic behavior as the Van der Waals fluid system, provided one treats the cosmological constant as a thermodynamic variable (pressure in an extended phase space. In this paper, we disclose the deep connection between charged AdS black holes and Van der Waals fluid system from an alternative point of view. We consider the mass of an AdS black hole as a function of square of the charge Q2 instead of the standard Q, i.e. M=M(S,Q2,P. We first justify such a change of view mathematically and then ask if a phase transition can occur as a function of Q2 for fixed P. Therefore, we write the equation of state as Q2=Q2(T,Ψ where Ψ (conjugate of Q2 is the inverse of the specific volume, Ψ=1/v. This allows us to complete the analogy of charged AdS black holes with Van der Waals fluid system and derive the phase transition as well as critical exponents of the system. We identify a thermodynamic instability in this new picture with real analogy to Van der Waals fluid with physically relevant Maxwell construction. We therefore study the critical behavior of isotherms in Q2–Ψ diagram and deduce all the critical exponents of the system and determine that the system exhibits a small–large black hole phase transition at the critical point (Tc,Qc2,Ψc. This alternative view is important as one can imagine such a change for a given single black hole i.e. acquiring charge which induces the phase transition. Finally, we disclose the microscopic properties of charged AdS black holes by using thermodynamic geometry. Interestingly, we find that scalar curvature has a gap between small and large black holes, and this gap becomes exceedingly large as one moves away from the critical point along the transition line. Therefore, we are able to attribute the sudden enlargement of the black hole to the strong repulsive nature of the internal constituents at the phase transition.
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Band-gap engineering of functional perovskites through quantum confinement and tunneling
DEFF Research Database (Denmark)
Castelli, Ivano Eligio; Pandey, Mohnish; Thygesen, Kristian Sommer
2015-01-01
An optimal band gap that allows for a high solar-to-fuel energy conversion efficiency is one of the key factors to achieve sustainability. We investigate computationally the band gaps and optical spectra of functional perovskites composed of layers of the two cubic perovskite semiconductors BaSnO3...... and BaTaO2N. Starting from an indirect gap of around 3.3 eV for BaSnO3 and a direct gap of 1.8 eV for BaTaO2N, different layerings can be used to design a direct gap of the functional perovskite between 2.3 and 1.2 eV. The variations of the band gap can be understood in terms of quantum confinement...
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Surface-enhanced Raman scattering sensing on black silicon
Energy Technology Data Exchange (ETDEWEB)
Gervinskas, Gediminas; Seniutinas, Gediminas; Hartley, Jennifer S.; Stoddart, Paul R.; Juodkazis, Saulius [Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC (Australia); The Australian National Fabrication Facility-ANFF, Victoria node, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC (Australia); Kandasamy, Sasikaran [Melbourne Centre for Nanofabrication, Clayton, VIC (Australia); Fahim, Narges F. [Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC (Australia)
2013-12-15
Reactive ion etching was used to fabricate black-Si over the entire surface area of 4-inch Si wafers. After 20 min of the plasma treatment, surface reflection well below 2% was achieved over the 300-1000 nm spectral range. The spikes of the black-Si substrates were coated by gold, resulting in an island film for surface-enhanced Raman scattering (SERS) sensing. A detection limit of 1 x 10{sup -6} M (at count rate > 10{sup 2} s{sup -1}. mW{sup -1}) was achieved for rhodamine 6G in aqueous solution when drop cast onto a {proportional_to} 100-nm-thick Au coating. The sensitivity increases for thicker coatings. A mixed mobile-on-immobile platform for SERS sensing is introduced by using dog-bone Au nanoparticles on the Au/black-Si substrate. The SERS intensity shows a non-linear dependence on the solid angle (numerical aperture of excitation/collection optics) for a thick gold coating that exhibits a 10 times higher enhancement. This shows promise for augmented sensitivity in SERS applications. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Income-Based Disparities in Early Elementary School Science Achievement
Curran, F. Chris
2017-01-01
This study documents gaps in kindergarten and first-grade science achievement by family income and explores the degree to which such gaps can be accounted for by student race/ethnicity, out-of-school activities, parental education, and school fixed effects. In doing so, it expands on prior research that documents disparate rates of science…
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Ismailidis, P; Kuster, M S; Jost, B; Giesinger, K; Behrend, H
2017-06-01
Increased range of motion (ROM) while maintaining joint stability is the goal of modern total knee arthroplasty (TKA). A biomechanical study has shown that small increases in flexion gap result in decreased tibiofemoral force beyond 90° flexion. The purpose of this paper was to investigate clinical implications of controlled increased flexion gap. Four hundred and four TKAs were allocated into one of two groups and analysed retrospectively. In the first group (n = 352), flexion gap exceeded extension gap by 2.5 mm, while in the second group (n = 52) flexion gap was equal to the extension gap. The procedures were performed from 2008 to 2012. The patients were reviewed 12 months postoperatively. Objective clinical results were assessed for ROM, mediolateral and sagittal stability. Patient-reported outcome measures were the WOMAC score and the Forgotten Joint Score (FJS-12). After categorizing postoperative flexion into three groups (poor < 90°, satisfactory 91°-119°, good ≥ 120°) significantly more patients in group 1 achieved satisfactory or good ROM (p = 0.006). Group 1 also showed a significantly higher mean FJS-12 (group 1: 73, group 2: 61, p = 0.02). The mean WOMAC score was 11 in the first and 14 in the second group (n.s.). Increase in flexion gap did not influence knee stability. The clinical relevance of this study is that a controlled flexion gap increase of 2.5 mm may have a positive effect on postoperative flexion and patient satisfaction after TKA. Neither knee stability in the coronal and sagittal planes nor complications were influenced by a controlled increase in flexion gap. III.
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Impurity-induced anisotropic semiconductor-semimetal transition in monolayer biased black phosphorus
Bui, D. H.; Yarmohammadi, Mohsen
2018-07-01
Taking into account the electron-impurity interaction within the continuum approximation of tight-binding model, the Born approximation, and the Green's function method, the main features of anisotropic electronic phase transition are investigated in monolayer biased black phosphorus (BP). To this end, we concentrated on the disordered electronic density of states (DOS), which gives useful information for electro-optical devices. Increasing the impurity concentration in both unbiased and biased impurity-infected single-layer BP, in addition to the decrease of the band gap, independent of the direction, leads to the midgap states and an extra Van Hove singularity inside and outside of the band gap, respectively. Furthermore, strong impurity scattering potentials lead to a semiconductor-semimetal transition and one more Van Hove singularity in x-direction of unbiased BP and surprisingly, this transition does not occur in biased BP. We found that there is no phase transition in y-direction. Since real applications require structures with modulated band gaps, we have studied the influence of different bias voltages on the disordered DOS in both directions, resulting in the increase of the band gap.
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New York: Expanding Time, Increasing Opportunities for Achievement
Miller, Tiffany D.
2014-01-01
New York is poised to take an important step to improve student achievement by expanding learning time for students attending high-poverty, low-performing schools. Recent district- and state-level investments in expanded learning time--a promising strategy to close achievement and opportunity gaps--will give students more time to learn core…
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Closing Yield Gaps: How Sustainable Can We Be?
Directory of Open Access Journals (Sweden)
Prajal Pradhan
Full Text Available Global food production needs to be increased by 60-110% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24% and 80% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P2O5, and K2O to attain the potential yields. Globally, N-fertilizer application needs to increase by 45-73%, P2O5-fertilizer by 22-46%, and K2O-fertilizer by 2-3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends
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Student achievement in science: A longitudinal look at individual and school differences
Martinez, Alina
The importance of science in today's technological society necessitates continued attention to students' experiences in science and specifically their achievement in science. There is a need to look at gender and race/ethnicity simultaneously when studying students' experiences in science and to explore factors related to higher achievement among students. Using data from the Longitudinal Study of American Youth, this study contributes to existing literature on student achievement in science by simultaneously exploring the effects of race/ethnicity and gender. Capitalizing on the availability of yearly science achievement scores, I present trajectories of student achievement from 7th to 12th grade. This study also includes an exploration of school effects. Overall, student achievement in science increases from 7th to 12th grade, although some leveling is seen in later grades. Growth in achievement differs by both gender and race/ethnicity, but racial/ethnic differences are larger than gender differences. Hispanic, Black, Asian, and White males score higher, on average, throughout the secondary grades than their female counterparts. Achievement scores of Asian students are consistently higher than White students, who in turn score higher than Hispanic and finally Black students. Both background and science-related factors help explain variation in achievement status and growth in achievement. Parental education is positively associated with achievement status among all groups except Black students for whom there is no effect of parental education. Science related resources in the home are positively associated with student achievement and the effect of these resources increases in later grades. Student achievement in science is also positively related to student course taking and attitude toward science. Furthermore, both the negative effect of viewing science as a male domain, which exists for males and females, and the positive effect of parental support for
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Black Silicon Solar Cells with Black Ribbons
DEFF Research Database (Denmark)
Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io
2016-01-01
We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...
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Achieving Energy Efficient Ship Operations Under Third Party Management
DEFF Research Database (Denmark)
Taudal Poulsen, René; Sornn-Friese, Henrik
2015-01-01
Profitable energy saving measures are often not fully implemented in shipping, causing energy efficiency gaps. The paper identifies energy efficiency gaps in ship operations, and explores their causes. Lack of information on energy efficiency, lack of energy training at sea and onshore and lack...... of time to produce and provide reliable energy efficiency information cause energy efficiency gaps. The paper brings together the energy efficiency and ship management literatures, demonstrating how ship management models influence energy efficiency in ship operations. Achieving energy efficiency in ship...
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Jimenez, Evelyn
2013-01-01
This capstone project applied Clark and Estes' (2008) gap analysis framework to identify performance gaps, develop perceived root causes, validate the causes, and formulate research-based solutions to present to Trojan High School. The purpose was to examine ways to increase the academic achievement of ELL students, specifically Latinos, by…
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How to Recover a Qubit That Has Fallen into a Black Hole.
Chatwin-Davies, Aidan; Jermyn, Adam S; Carroll, Sean M
2015-12-31
We demonstrate an algorithm for the retrieval of a qubit, encoded in spin angular momentum, that has been dropped into a no-firewall black hole. Retrieval is achieved analogously to quantum teleportation by collecting Hawking radiation and performing measurements on the black hole. Importantly, these methods require only the ability to perform measurements from outside the event horizon.
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From Bystander to Upstander Teacher for Gifted Black Students Accused of Acting White
Grantham, Tarek C.; Biddle, Winfred H.
2014-01-01
Gifted Black students experience many barriers that contribute to their under-representation in gifted and advanced programs. One of the greatest negative influences comes from peer accusations of acting White that undermine gifted and high-achieving Black students' academic motivation and their interest in challenging courses and programs.…
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Immigrant Students’ Achievements in Croatia, Serbia and Slovenia in Context
Directory of Open Access Journals (Sweden)
Nika Šušterič
2011-01-01
Full Text Available Achievement gaps between immigrant and native students indicate failure to assure educational equity in the majority of countries assessed by the Programme for International Student Assessment in 2009 (PISA, 2009. The present article explains disparate achievement results in Europe, first testing the hypothesis of old and new democracies. In further contextualisation of the achievement results, the analysis seeks explanations beyond the common education system explanatory model. Specifically, the article considers results from Croatia, Serbia and Slovenia, highlighting the significance of language distance between native and immigrant students as well as migration regimes as important factors in creating or reducing the achievement gap between native and immigrant students. Evidence has been found that immigrant students score worse in countries with guest labour immigration regimes than in the countries with large scale forced immigration of people of the same ethnic (linguistic origin.
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Eternal and evanescent black holes and accelerating mirror analogs
Good, Michael R. R.; Linder, Eric V.
2018-03-01
The analogy between black hole radiation and accelerating mirror radiation (the dynamical Casimir effect) is particularly strong for mirror trajectories giving rise to a constant thermal flux of particles. We present new ways to achieve such thermal plateaus, and customize their finite, semi-infinite, and eternal presence, corresponding to forming/collapsing, complete-evaporation/remnants, and eternal black holes. We find simple expressions for the energy flux in terms of the mirror rapidity as a function of proper time and null time.
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Acoustic black holes: recent developments in the theory and applications.
Krylov, Victor
2014-08-01
Acoustic black holes are relatively new physical objects that have been introduced and investigated mainly during the last decade. They can absorb almost 100% of the incident wave energy, and this makes them very attractive for such traditional engineering applications as vibration damping in different engineering structures and sound absorption in gases and liquids. They also could be useful for some ultrasonic devices using Lamb wave propagation to provide anechoic termination for such waves. So far, acoustic black holes have been investigated mainly for flexural waves in thin plates, for which the required gradual changes in local wave velocity with distance can be easily achieved by changing the plates' local thickness. The present paper provides a brief review of the theory of acoustic black holes, including their comparison with optic black holes introduced about five years ago. Review is also given of the recent experimental work carried out at Loughborough University on damping structural vibrations using the acoustic black hole effect. This is followed by the discussion on potential applications of the acoustic black hole effect for sound absorption in air.
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Gravitational properties of monopole spacetimes near the black hole threshold
International Nuclear Information System (INIS)
Lue, Arthur; Weinberg, Erick J.
2000-01-01
Although nonsingular spacetimes and those containing black holes are qualitatively quite different, there are continuous families of configurations that connect the two. In this paper we use self-gravitating monopole solutions as tools for investigating the transition between these two types of spacetimes. We show how causally distinct regions emerge as the black hole limit is achieved, even though the measurements made by an external observer vary continuously. We find that near-critical solutions have a naturally defined entropy, despite the absence of a true horizon, and that this has a clear connection with the Hawking-Bekenstein entropy. We find that certain classes of near-critical solutions display naked black hole behavior, although they are not truly black holes at all. Finally, we present a numerical simulation illustrating how an incident pulse of matter can induce the dynamical collapse of a monopole into an extremal black hole. We discuss the implications of this process for the third law of black hole thermodynamics. (c) 2000 The American Physical Society
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Terrier Black Brant VC design characteristics and program status. [rocket development
Payne, B. R.; Mayo, E. E.
1979-01-01
In the present paper, the design analysis of the Terrier-Black Brant VC, representing the latest addition to the Black Brant rocket family, is discussed, including the aerodynamic, structural, thermal, and operational aspects. An appreciable increase in apogee, as compared to the BBVC and Nike/BBVC, is achieved without any modifications to the well-proven BBV motor or degradation of the thermal or dynamic flight environment.
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Opening complete band gaps in two dimensional locally resonant phononic crystals
Zhou, Xiaoling; Wang, Longqi
2018-05-01
Locally resonant phononic crystals (LRPCs) which have low frequency band gaps attract a growing attention in both scientific and engineering field recently. Wide complete locally resonant band gaps are the goal for researchers. In this paper, complete band gaps are achieved by carefully designing the geometrical properties of the inclusions in two dimensional LRPCs. The band structures and mechanisms of different types of models are investigated by the finite element method. The translational vibration patterns in both the in-plane and out-of-plane directions contribute to the full band gaps. The frequency response of the finite periodic structures demonstrate the attenuation effects in the complete band gaps. Moreover, it is found that the complete band gaps can be further widened and lowered by increasing the height of the inclusions. The tunable properties by changing the geometrical parameters provide a good way to open wide locally resonant band gaps.
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Blockmans, S.
2015-01-01
Russia’s annexation of Crimea and its destabilization of Eastern Ukraine have radically altered the European security order, with the Black Sea region becoming an acutely contested geostrategic zone. Russia’s strategic interests in the Black Sea region, especially in terms of energy and military
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Leu, Donald J.; Forzani, Elena; Kennedy, Clint
2015-01-01
A recent study in "Reading Research Quarterly" provided evidence that an online reading achievement gap, based on income inequality, exists that is separate and independent from the well-known achievement gap in offline reading. This column briefly reviews the evidence and provides an initial set of instructional suggestions that may be…
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Teen Pregnancy and the Achievement Gap among Urban Minority Youth
Basch, Charles E.
2011-01-01
Objectives: To outline the prevalence and disparities of teen pregnancy among school-aged urban minority youth, causal pathways through which nonmarital teen births adversely affects academic achievement, and proven or promising approaches for schools to address this problem. Methods: Literature review. Results: In 2006, the birth rate among 15-…
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Do Interim Assessments Reduce the Race and SES Achievement Gaps?
Konstantopoulos, Spyros; Li, Wei; Miller, Shazia R.; van der Ploeg, Arie
2017-01-01
The authors examined differential effects of interim assessments on minority and low socioeconomic status students' achievement in Grades K-6. They conducted a large-scale cluster randomized experiment in 2009-2010 to evaluate the impact of Indiana's policy initiative introducing interim assessments statewide. The authors used 2-level models to…
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Black holes are neither particle accelerators nor dark matter probes.
McWilliams, Sean T
2013-01-04
It has been suggested that maximally spinning black holes can serve as particle accelerators, reaching arbitrarily high center-of-mass energies. Despite several objections regarding the practical achievability of such high energies, and demonstrations past and present that such large energies could never reach a distant observer, interest in this problem has remained substantial. We show that, unfortunately, a maximally spinning black hole can never serve as a probe of high energy collisions, even in principle and despite the correctness of the original diverging energy calculation. Black holes can indeed facilitate dark matter annihilation, but the most energetic photons can carry little more than the rest energy of the dark matter particles to a distant observer, and those photons are actually generated relatively far from the black hole where relativistic effects are negligible. Therefore, any strong gravitational potential could probe dark matter equally well, and an appeal to black holes for facilitating such collisions is unnecessary.
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International Nuclear Information System (INIS)
Feast, M.W.
1981-01-01
This article deals with two questions, namely whether it is possible for black holes to exist, and if the answer is yes, whether we have found any yet. In deciding whether black holes can exist or not the central role in the shaping of our universe played by the forse of gravity is discussed, and in deciding whether we are likely to find black holes in the universe the author looks at the way stars evolve, as well as white dwarfs and neutron stars. He also discusses the problem how to detect a black hole, possible black holes, a southern black hole, massive black holes, as well as why black holes are studied
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MIGRATION TRAPS IN DISKS AROUND SUPERMASSIVE BLACK HOLES
Energy Technology Data Exchange (ETDEWEB)
Bellovary, Jillian M.; Low, Mordecai-Mark Mac; McKernan, Barry; Ford, K. E. Saavik [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, NY 10024 (United States)
2016-03-10
Accretion disks around supermassive black holes (SMBHs) in active galactic nuclei (AGNs) contain stars, stellar mass black holes, and other stellar remnants, which perturb the disk gas gravitationally. The resulting density perturbations exert torques on the embedded masses causing them to migrate through the disk in a manner analogous to planets in protoplanetary disks. We determine the strength and direction of these torques using an empirical analytic description dependent on local disk gradients, applied to two different analytic, steady-state disk models of SMBH accretion disks. We find that there are radii in such disks where the gas torque changes sign, trapping migrating objects. Our analysis shows that major migration traps generally occur where the disk surface density gradient changes sign from positive to negative, around 20–300R{sub g}, where R{sub g} = 2GM/c{sup 2} is the Schwarzschild radius. At these traps, massive objects in the AGN disk can accumulate, collide, scatter, and accrete. Intermediate mass black hole formation is likely in these disk locations, which may lead to preferential gap and cavity creation at these radii. Our model thus has significant implications for SMBH growth as well as gravitational wave source populations.
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Wide gap Chern Mott insulating phases achieved by design
Guo, Hongli; Gangopadhyay, Shruba; Köksal, Okan; Pentcheva, Rossitza; Pickett, Warren E.
2017-12-01
Quantum anomalous Hall insulators, which display robust boundary charge and spin currents categorized in terms of a bulk topological invariant known as the Chern number (Thouless et al Phys. Rev. Lett. 49, 405-408 (1982)), provide the quantum Hall anomalous effect without an applied magnetic field. Chern insulators are attracting interest both as a novel electronic phase and for their novel and potentially useful boundary charge and spin currents. Honeycomb lattice systems such as we discuss here, occupied by heavy transition-metal ions, have been proposed as Chern insulators, but finding a concrete example has been challenging due to an assortment of broken symmetry phases that thwart the topological character. Building on accumulated knowledge of the behavior of the 3d series, we tune spin-orbit and interaction strength together with strain to design two Chern insulator systems with bandgaps up to 130 meV and Chern numbers C = -1 and C = 2. We find, in this class, that a trade-off between larger spin-orbit coupling and strong interactions leads to a larger gap, whereas the stronger spin-orbit coupling correlates with the larger magnitude of the Hall conductivity. Symmetry lowering in the course of structural relaxation hampers obtaining quantum anomalous Hall character, as pointed out previously; there is only mild structural symmetry breaking of the bilayer in these robust Chern phases. Recent growth of insulating, magnetic phases in closely related materials with this orientation supports the likelihood that synthesis and exploitation will follow.
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Patterns of Black Excellence. Ethics and Public Policy Reprint 5.
Sowell, Thomas
The history of the advancement of blacks in the United States is almost a laboratory study of human achievement. But the story of how millions of people developed from the depths of slavery--acquired work skills, personal discipline, human ideals, and the whole complex of knowledge and values required for achievement in a modern society--is a…
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Black silicon with black bus-bar strings
DEFF Research Database (Denmark)
Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io
2016-01-01
We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...
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Nonthermal production of dark matter from primordial black holes
Allahverdi, Rouzbeh; Dent, James; Osinski, Jacek
2018-03-01
We present a scenario for nonthermal production of dark matter from evaporation of primordial black holes. A period of very early matter domination leads to formation of black holes with a maximum mass of ≃2 ×108 g , whose subsequent evaporation prior to big bang nucleosynthesis can produce all of the dark matter in the Universe. We show that the correct relic abundance can be obtained in this way for thermally underproduced dark matter in the 100 GeV-10 TeV mass range. To achieve this, the scalar power spectrum at small scales relevant for black hole formation should be enhanced by a factor of O (105) relative to the scales accessible by the cosmic microwave background experiments.
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The prototype GAPS (pGAPS) experiment
International Nuclear Information System (INIS)
Mognet, S.A.I.; Aramaki, T.; Bando, N.; Boggs, S.E.; Doetinchem, P. von; Fuke, H.; Gahbauer, F.H.; Hailey, C.J.; Koglin, J.E.; Madden, N.; Mori, K.; Okazaki, S.; Ong, R.A.; Perez, K.M.; Tajiri, G.; Yoshida, T.; Zweerink, J.
2014-01-01
The General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS (pGAPS) experiment was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6 h, with over 3 h at float altitude (∼33km). Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded
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Electrocoagulation treatment of black liquor from paper industry.
Zaied, M; Bellakhal, N
2009-04-30
The procedure of electrocoagulation is an effective, fast and economic technique for treatment of black liquor resulting from paper industry. The effect of electrolysis time, current density, type of electrode material and initial pH were studied in an attempt to achieve a higher removal capacity. Under the optimal experimental conditions (initial pH 7, t=50 min and J=14 mA cm(-2)), the treatment of black liquor by electrocoagulation has led to a removal capacity of 98% of COD, 92% of polyphenols and 99% of color intensity with a good repeatability (R.S.D.industrial interest of this electrochemical process.
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Collins, Kristina Henry
2018-01-01
What is Black student's science, technology, engineering, and mathematics (STEM) identity? The author addresses this question through a synthesis of the literature that includes studies that explore Black student identity. Background information regarding STEM achievement and persistence followed by empirical studies that explore STEM attitudes…
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International Nuclear Information System (INIS)
Emparan, Roberto; Reall, Harvey S
2006-01-01
A black ring is a five-dimensional black hole with an event horizon of topology S 1 x S 2 . We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)
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Bowleg, Lisa; Teti, Michelle; Massie, Jenné S; Patel, Aditi; Malebranche, David J; Tschann, Jeanne M
2011-05-01
Research documents the link between traditional ideologies of masculinity and sexual risk among multi-ethnic male adolescents and White male college students, but similar research with Black heterosexual men is scarce. This exploratory study addressed this gap through six focus groups with 41 Black, low- to middle-income heterosexual men aged 19 to 51 years in Philadelphia, PA. Analyses highlighted two explicit ideologies of masculinity: that Black men should have sex with multiple women, often concurrently, and that Black men should not be gay or bisexual. Analyses also identified two implicit masculinity ideologies: the perception that Black heterosexual men cannot decline sex, even risky sex, and that women should be responsible for condom use. The study's implications for HIV prevention with Black heterosexual men are discussed. © 2011 Taylor & Francis
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"Black Like Me": Reframing Blackness for Decolonial Politics
Dei, George J. Sefa
2018-01-01
From a particular vantage point, as an African-born scholar with a politics to affirm my Black subjectivity and Indigeneity in a diasporic context, my article engages a (re)theorization of Blackness for decolonial politics. Building on existing works of how Black scholars, themselves, have theorized Blackness, and recognizing the fluid,…
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Graded band-gap engineering for increased efficiency in CZTS solar cells
Ferhati, H.; Djeffal, F.
2018-02-01
In this paper, we propose a potential high efficiency Cu2ZnSn(S,Se)4/CdS (CZTS) solar cell design based on graded band-gap engineering that can offer the benefits of improved absorption behavior and reduced recombination effects. Moreover, a new hybrid approach based on analytical modeling and Particle Swarm Optimization (PSO) is proposed to determinate the optimal band-gap profile of the amended CZTS absorber layer to achieve further efficiency enhancement. It is found that the proposed design exhibits superior performance, where a high efficiency of 16.9% is recorded for the optimized solar cell with a relative improvement of 92%, compared with the reference cell efficiency of 8.8%. Likewise, the optimized CZTS solar cell with a graded band-gap enables achieving a higher open circuit voltage of 889 mV, a short-circuit current of 28.5 mA and a fill factor of 66%. Therefore, the optimized CZTS-based solar cell with graded-band gap paradigm pinpoints a new path toward recording high-efficiency thin-film solar cells through enhancing carrier collection and reducing the recombination rate.
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Sustainability Tools Inventory - Initial Gaps Analysis | Science ...
This report identifies a suite of tools that address a comprehensive set of community sustainability concerns. The objective is to discover whether "gaps" exist in the tool suite’s analytic capabilities. These tools address activities that significantly influence resource consumption, waste generation, and hazard generation including air pollution and greenhouse gases. In addition, the tools have been evaluated using four screening criteria: relevance to community decision making, tools in an appropriate developmental stage, tools that may be transferrable to situations useful for communities, and tools with requiring skill levels appropriate to communities. This document provides an initial gap analysis in the area of community sustainability decision support tools. It provides a reference to communities for existing decision support tools, and a set of gaps for those wishing to develop additional needed tools to help communities to achieve sustainability. It contributes to SHC 1.61.4
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Ethnicity and Gender Gaps in Early Childhood
Hansen, Kirstine; Jones, Elizabeth M.
2011-01-01
Gender differences in academic performance and achievement have been of policy concern for decades--both interest in lower performance by girls in the areas of mathematics and science and, more recently, in boys' underperformance in most other academic areas. Much previous research has focused on gender gaps, while overlooking other factors that…
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Global Gaps in Clean Energy RD and D
Energy Technology Data Exchange (ETDEWEB)
NONE
2010-07-01
This report seeks to inform decision makers seeking to prioritise RD&D investments in a time of financial uncertainty. It is an update of the December 2009 IEA report Global Gaps in Clean Energy Research, Development and Demonstration, which examined whether rates of LCET investment were sufficient to achieve shared global energy and environmental goals (IEA,2009). It discusses the impact of the green stimulus spending announcements, and provides private sector perspectives on priorities for government RD&D spending. Finally, it includes a revised assessment of the gaps in public RD&D, together with suggestions for possible areas for expanded international collaboration on specific LCETs. The conclusion re-affirms the first Global Gaps study finding that governments and industry need to dramatically increase their spending on RD&D for LCETs.
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Quintessence background for 5D Einstein-Gauss-Bonnet black holes
Ghosh, Sushant G.; Amir, Muhammed; Maharaj, Sunil D.
2017-08-01
As we know that the Lovelock theory is an extension of the general relativity to the higher-dimensions, in this theory the first- and the second-order terms correspond to general relativity and the Einstein-Gauss-Bonnet gravity, respectively. We obtain a 5D black hole solution in Einstein-Gauss-Bonnet gravity surrounded by the quintessence matter, and we also analyze their thermodynamical properties. Owing to the quintessence corrected black hole, the thermodynamic quantities have also been corrected except for the black hole entropy, and a phase transition is achievable. The phase transition for the thermodynamic stability is characterized by a discontinuity in the specific heat at r=r_C, with the stable (unstable) branch for r ) r_C.
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Influence of carbon black distribution on performance of oxide cathodes for Li ion batteries
International Nuclear Information System (INIS)
Dominko, Robert; Gaberscek, Miran; Drofenik, Jernej; Bele, Marjan; Jamnik, Janez
2003-01-01
The influence of carbon black content and carbon black distribution on performance of oxide-based cathodes, such as LiCoO 2 and LiMn 2 O 4 , is investigated. The electronic conductivity of oxide material/carbon black composites is compared with electrochemical characteristics of the same composites. Uniformity of carbon black distribution in cathode composites is achieved using novel coating technology in cathode preparation. In this technology, the active particles are first pretreated in a gelatin solution. The adsorbed gelatin then controls the deposition of carbon black so that carbon black particles are uniformly distributed in the final composite. The influence of various parameters, such as pH of gelatin, amount of gelatin and concentration of carbon black on the uniformity of carbon black distribution is investigated. It is shown that the conventional technology of cathode preparation yields quite non-uniform distribution of carbon black in cathode material. At the end, we demonstrate that uniformity of carbon black distribution has a crucial impact on reversible capacity, especially at high current densities
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The prototype GAPS (pGAPS) experiment
Energy Technology Data Exchange (ETDEWEB)
Mognet, S.A.I., E-mail: mognet@astro.ucla.edu [University of California, Los Angeles, CA 90095 (United States); Aramaki, T. [Columbia University, New York, NY 10027 (United States); Bando, N. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Boggs, S.E.; Doetinchem, P. von [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Fuke, H. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Gahbauer, F.H.; Hailey, C.J.; Koglin, J.E.; Madden, N. [Columbia University, New York, NY 10027 (United States); Mori, K.; Okazaki, S. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Ong, R.A. [University of California, Los Angeles, CA 90095 (United States); Perez, K.M.; Tajiri, G. [Columbia University, New York, NY 10027 (United States); Yoshida, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Zweerink, J. [University of California, Los Angeles, CA 90095 (United States)
2014-01-21
The General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS (pGAPS) experiment was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6 h, with over 3 h at float altitude (∼33km). Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded.
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Winter Responses of Forest Birds to Habitat Corridors and Gaps
Directory of Open Access Journals (Sweden)
Colleen Cassady St. Clair
1998-12-01
Full Text Available Forest fragmentation and habitat loss may disrupt the movement or dispersal of forest-dwelling birds. Despite much interest in the severity of these effects and ways of mitigating them, little is known about actual movement patterns in different habitat types. We studied the movement of wintering resident birds, lured by playbacks of mobbing calls, to compare the willingness of forest birds to travel various distances in continuous forest, along narrow corridors (fencerows, and across gaps in forest cover. We also quantified the willingness of Black-capped Chickadees (Poecile atricapillus to cross gaps when alternative forested detour routes were available. All species were less likely to respond to the calls as distance increased to 200 m, although White-breasted Nuthatches (Sitta carolinensis and Hairy Woodpeckers (Picoides villosus were generally less likely to respond than chickadees and Downy Woodpeckers (P. pubescens. Chickadees were as likely to travel in corridors as in continuous forest, but were less likely to cross gaps as the gap distance increased. The other species were less willing to travel in corridors and gaps relative to forest, and the differences among habitats also increased with distance. For chickadees, gap-crossing decisions in the presence of forested detours varied over the range of distances that we tested, and were primarily influenced by detour efficiency (the length of the shortcut relative to the available detour. Over short distances, birds used forested detours, regardless of their efficiency. As absolute distances increased, birds tended to employ larger shortcuts in the open when detour efficiency was low or initial distance in the open was high, but they limited their distance from the nearest forest edge to 25 m. Thus, chickadees were unwilling to cross gaps of > 50 m when they had forested alternatives, yet they sometimes crossed gaps as large as 200 m when no such choice existed. Our results suggest that
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The Weak Gravity Conjecture and the axionic black hole paradox
Hebecker, Arthur; Soler, Pablo
2017-09-01
In theories with a perturbatively massless 2-form (dual to an axion), a paradox may arise in the process of black hole evaporation. Schwarzschild black holes can support a non-trivial Wilson-line-type field, the integral of the 2-form around their horizon. After such an `axionic black hole' evaporates, the Wilson line must be supported by the corresponding 3-form field strength in the region formerly occupied by the black hole. In the limit of small axion decay-constant f, the energy required for this field configuration is too large. Thus, energy cannot be conserved in the process of black hole evaporation. The natural resolution of this paradox is through the presence of light strings, which allow the black hole to "shed" its axionic hair sufficiently early. This gives rise to a new Weak-Gravity-type argument in the 2-form context: small coupling, in this case f , enforces the presence of light strings or a low cutoff. We also discuss how this argument may be modified in situations where the weak coupling regime is achieved in the low-energy effective theory through an appropriate gauging of a model with a vector field and two 2-forms.
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CONTINUOUS ABORT GAP CLEANING AT RHIC
International Nuclear Information System (INIS)
DREES, A.; FLILLER, R.III.; FU, W.; MICHNOFF, R.
2004-01-01
Since the RHIC Au-Au run in the year 2001 the 200 MHz cavity system was used at storage and a 28 MHz system during injection and acceleration. The rebucketing procedure potentially causes a higher debunching rate of heavy ion beams in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam can easily account for more than 50% of the total beam intensity. This effect is even stronger with the achieved high intensities of the RHIC Au-Au run in 2004. A beam abort at the presence of a lot of debunched beam bears the risk of magnet quenching and experimental detector damage due to uncontrolled beam losses. Thus it is desirable to avoid any accumulation of debunched beam from the beginning of each store, in particular to anticipate cases of unscheduled beam aborts due to a system failure. A combination of a fast transverse kickers and the new 2-stage copper collimator system are used to clean the abort gap continuously throughout the store with a repetition rate of 1 Hz. This report gives. an overview of the new gap cleaning procedure and the achieved performance
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Contoured-gap coaxial guns for imploding plasma liner experiments
Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.
2014-10-01
Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.
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CIRCUMBINARY MAGNETOHYDRODYNAMIC ACCRETION INTO INSPIRALING BINARY BLACK HOLES
Energy Technology Data Exchange (ETDEWEB)
Noble, Scott C.; Mundim, Bruno C.; Nakano, Hiroyuki; Campanelli, Manuela; Zlochower, Yosef [Center for Computational Relativity and Gravitation, Rochester Institute of Technology, Rochester, NY 14623 (United States); Krolik, Julian H. [Physics and Astronomy Department, Johns Hopkins University, Baltimore, MD 21218 (United States); Yunes, Nicolas, E-mail: scn@astro.rit.edu [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)
2012-08-10
We have simulated the magnetohydrodynamic evolution of a circumbinary disk surrounding an equal-mass binary comprising two non-spinning black holes during the period in which the disk inflow time is comparable to the binary evolution time due to gravitational radiation. Both the changing spacetime and the binary orbital evolution are described by an innovative technique utilizing high-order post-Newtonian approximations. Prior to the beginning of the inspiral, the structure of the circumbinary disk is predicted well by extrapolation from Newtonian results: a gap of roughly two binary separation radii is cleared, and matter piles up at the outer edge of this gap as inflow is retarded by torques exerted by the binary; the accretion rate is roughly half its value at large radius. During inspiral, the inner edge of the disk initially moves inward in coordination with the shrinking binary, but-as the orbital evolution accelerates-the inward motion of the disk edge falls behind the rate of binary compression. In this stage, the binary torque falls substantially, but the accretion rate decreases by only 10%-20%. When the binary separation is tens of gravitational radii, the rest-mass efficiency of disk radiation is a few percent, suggesting that supermassive binary black holes could be very luminous at this stage of their evolution. Inner disk heating is modulated at a beat frequency comparable to the binary orbital frequency. However, a disk with sufficient surface density to be luminous may be optically thick, suppressing periodic modulation of the luminosity.
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Black molecular adsorber coatings for spaceflight applications
Abraham, Nithin S.; Hasegawa, Mark M.; Straka, Sharon A.
2014-09-01
The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.
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Site of delivery contribution to black-white severe maternal morbidity disparity.
Howell, Elizabeth A; Egorova, Natalia N; Balbierz, Amy; Zeitlin, Jennifer; Hebert, Paul L
2016-08-01
The black-white maternal mortality disparity is the largest disparity among all conventional population perinatal health measures, and the mortality gap between black and white women in New York City has nearly doubled in recent years. For every maternal death, 100 women experience severe maternal morbidity, a life-threatening diagnosis, or undergo a life-saving procedure during their delivery hospitalization. Like maternal mortality, severe maternal morbidity is more common among black than white women. A significant portion of maternal morbidity and mortality is preventable, making quality of care in hospitals a critical lever for improving outcomes. Hospital variation in risk-adjusted severe maternal morbidity rates exists. The extent to which variation in hospital performance on severe maternal morbidity rates contributes to black-white disparities in New York City hospitals has not been studied. We examined the extent to which black-white differences in severe maternal morbidity rates in New York City hospitals can be explained by differences in the hospitals in which black and white women deliver. We conducted a population-based study using linked 2011-2013 New York City discharge and birth certificate datasets (n = 353,773 deliveries) to examine black-white differences in severe maternal morbidity rates in New York City hospitals. A mixed-effects logistic regression with a random hospital-specific intercept was used to generate risk-standardized severe maternal morbidity rates for each hospital (n = 40). We then assessed differences in the distributions of black and white deliveries among these hospitals. Severe maternal morbidity occurred in 8882 deliveries (2.5%) and was higher among black than white women (4.2% vs 1.5%, P rates among New York City hospitals ranged from 0.8 to 5.7 per 100 deliveries. White deliveries were more likely to be delivered in low-morbidity hospitals: 65% of white vs 23% of black deliveries occurred in hospitals in the lowest
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Closing Yield Gaps: How Sustainable Can We Be?
Pradhan, Prajal; Fischer, Günther; van Velthuizen, Harrij; Reusser, Dominik E.; Kropp, Juergen P.
2015-01-01
Global food production needs to be increased by 60–110% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24% and 80% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P2O5, and K2O) to attain the potential yields. Globally, N-fertilizer application needs to increase by 45–73%, P2O5-fertilizer by 22–46%, and K2O-fertilizer by 2–3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends on the way
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Gilbert, Keon L; Ray, Rashawn; Siddiqi, Arjumand; Shetty, Shivan; Baker, Elizabeth A; Elder, Keith; Griffith, Derek M
2016-01-01
Over the past two decades, there has been growing interest in improving black men's health and the health disparities affecting them. Yet, the health of black men consistently ranks lowest across nearly all groups in the United States. Evidence on the health and social causes of morbidity and mortality among black men has been narrowly concentrated on public health problems (e.g., violence, prostate cancer, and HIV/AIDS) and determinants of health (e.g., education and male gender socialization). This limited focus omits age-specific leading causes of death and other social determinants of health, such as discrimination, segregation, access to health care, employment, and income. This review discusses the leading causes of death for black men and the associated risk factors, as well as identifies gaps in the literature and presents a racialized and gendered framework to guide efforts to address the persistent inequities in health affecting black men.
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Watts, Thomas D.; Wright, Roosevelt
1988-01-01
Examines some aspects of the problem of alcoholism among Blacks, asserting that Black alcoholism can best be considered in an ecological, environmental, sociocultural, and public health context. Notes need for further research on alcoholism among Blacks and for action to reduce the problem of Black alcoholism. (NB)
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Sulfate reduction in an entrained-flow black liquor gasifier
Energy Technology Data Exchange (ETDEWEB)
Kymaelaeinen, M.; Janka, K. [Tampella Power, Tampere (Finland); Frederick, W.J.; Littau, M.; Sricharoenchaikul, V.; Jivakanun, N.; Waag, K. [Oregon State Univ., Corvallis, OR (United States). Dept. of Chemical Engineering
1995-12-31
Sulfate reduction and carbon conversion during pyrolysis and gasification of black liquor particles were experimentally studied in a laminar entrained-flow reactor. A model was also developed to simulate an entrained-flow black liquor gasifier. Experimental results were then compared to model calculations. Results indicated that carbon must be present to get a high degree of sulfate reduction during gasification. It is therefore important to balance the rates of carbon conversion and sulfate reduction. High local temperatures in the reactor should be avoided so that carbon does not convert too rapidly, but temperatures of nearly 1000 degrees C are required to achieve good sulfate reduction. It was suggested that a new equation was needed to adequately predict sulfate reduction in an entrained-flow black liquor gasifier. 12 refs., 8 figs., 5 tabs.
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Few-Layer Black Phosphorus Carbide Field-Effect Transistor via Carbon Doping.
Tan, Wee Chong; Cai, Yongqing; Ng, Rui Jie; Huang, Li; Feng, Xuewei; Zhang, Gang; Zhang, Yong-Wei; Nijhuis, Christian A; Liu, Xinke; Ang, Kah-Wee
2017-06-01
Black phosphorus carbide (b-PC) is a new family of layered semiconducting material that has recently been predicted to have the lightest electrons and holes among all known 2D semiconductors, yielding a p-type mobility (≈10 5 cm 2 V -1 s -1 ) at room temperature that is approximately five times larger than the maximum value in black phosphorus. Here, a high-performance composite few-layer b-PC field-effect transistor fabricated via a novel carbon doping technique which achieved a high hole mobility of 1995 cm 2 V -1 s -1 at room temperature is reported. The absorption spectrum of this material covers an electromagnetic spectrum in the infrared regime not served by black phosphorus and is useful for range finding applications as the earth atmosphere has good transparency in this spectral range. Additionally, a low contact resistance of 289 Ω µm is achieved using a nickel phosphide alloy contact with an edge contacted interface via sputtering and thermal treatment. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Predicting the academic performance of Asian, black, and Hispanic optometry students.
Kegel-Flom, P
1990-03-01
As optometry schools receive increasing numbers of Asian, Black, and Hispanic applications, it is appropriate for us to ask whether minority students differ in meaningful ways from nonminority students in measures used in admissions, and whether these variables have differential validity in predicting their achievement in optometry school. This study compares Asian, Black, Hispanic, and nonminority students at entry to the University of Houston College of Optometry (UHCO) from 1981 through 1986 and tests the validity of admissions indices to predict optometry grades, academic dropout, and high-level achievement for these ethnic groups. Although preoptometry grade point average (GPA) was the best predictor of optometry grades for all students, measures of verbal ability were additional predictors for Asian students and, for Black and Hispanic students, ability in study/reading and math were predictors. In addition, personality inventory measures and ratings of the competitiveness of the undergraduate institution were important in differentiating minority academic dropouts from retained students. Suggestions are made for optometry college programs which will enhance the probability of success for minority students.
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Immigrant Students' Achievements in Croatia, Serbia and Slovenia in Context
Šori, Iztok; Šušteric, Nika; Gaber, Slavko
2011-01-01
Achievement gaps between immigrant and native students indicate failure to assure educational equity in the majority of countries assessed by the Programme for International Student Assessment in 2009 (PISA, 2009). The present article explains disparate achievement results in Europe, first testing the hypothesis of old and new democracies. In…
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Family Characteristics and Elementary School Achievement in an Urban Ghetto
Solomon, Daniel; And Others
1972-01-01
The relationships of sex, father absence, family size, and birth order to factor scores representing general academic achievement'' were investigated in a sample of urban black ghetto fifth-grade children. Significant main effects were found for sex and family size. (Author)
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Energy Technology Data Exchange (ETDEWEB)
Kleist, A.
1997-07-01
The `hydrostatic machines` project was concerned with the examination of sealing and bearing gaps in hydraulic machines with the aim of creating a useful simulation tool for designing these gaps. In order to achieve this difficult target, extensive experimental investigations were carried out. A simulation program for the static calculation of sealing and bearing gaps was developed for the key gap bearing and the valve gap. The third main point of the experimental investigations was the examination of the piston/cylinder gap of a radial piston pump. The simulation was able to be verified from experimental results. (orig./AKF) [Deutsch] Das Projekt `Hydrostatische Maschinen` befasste sich mit der Untersuchung hydrostatischen Dicht- und Lagerfugen in hydraulischen Maschinen mit Ziel, fuer die Auslegung dieser Spalte ein handhabbares Simulationswerkzeug zu schaffen. Um dieses hochgesteckte Ziel zu erreichen, wurden umfangreiche experimentelle Untersuchungen durchgefuehrt. Fuer die Keilspaltlagerung und den Ventilsplat wurde ein Simulationsprogramm fuer die stationaere Berechnung von Dicht- und Lagerfugen entwickelt. Der dritte Schwerpunkt der experimentellen Untersuchungen war die Untersuchung des Kolben-Zylinder-Spaltes einer Radialkolbenpumpe. Die Simulation konnte anhand der experimentellen Ergebnisse verifiziert werden. (orig./AKF)
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2011-04-20
... Ranger District, Rio Grande National Forest; CO; Black Mesa Vegetation Management Project AGENCY: Forest... Web site http://www.fs.usda.gov/riogrande under ``Land & Resource Management'', then ``Projects'' on... need for the Black Mesa Vegetation Management Project is move toward achieving long-term desired...
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Directory of Open Access Journals (Sweden)
Tetsuro Tamaki
Full Text Available Losses in vital functions of the somatic motor and sensory nervous system are induced by severe long-gap peripheral nerve transection injury. In such cases, autologous nerve grafts are the gold standard treatment, despite the unavoidable sacrifice of other healthy functions, whereas the prognosis is not always favorable. Here, we use human skeletal muscle-derived stem cells (Sk-SCs to reconstitute the function after long nerve-gap injury. Muscles samples were obtained from the amputated legs from 9 patients following unforeseen accidents. The Sk-SCs were isolated using conditioned collagenase solution, and sorted as CD34+/45- (Sk-34 and CD34-/45-/29+ (Sk-DN/29+ cells. Cells were separately cultured/expanded under optimal conditions for 2 weeks, then injected into the athymic nude mice sciatic nerve long-gap model (7-mm bridging an acellular conduit. After 8-12 weeks, active cell engraftment was observed only in the Sk-34 cell transplanted group, showing preferential differentiation into Schwann cells and perineurial/endoneurial cells, as well as formation of the myelin sheath and perineurium/endoneurium surrounding regenerated axons, resulted in 87% of numerical recovery. Differentiation into vascular cell lineage (pericyte and endothelial cells were also observed. A significant tetanic tension recovery (over 90% of downstream muscles following electrical stimulation of the sciatic nerve (at upper portion of the gap was also achieved. In contrast, Sk-DN/29+ cells were completely eliminated during the first 4 weeks, but relatively higher numerical (83% vs. 41% in axon and functional (80% vs. 60% in tetanus recovery than control were observed. Noteworthy, significant increase in the formation of vascular networks in the conduit during the early stage (first 2 weeks of recovery was observed in both groups with the expression of key factors (mRNA and protein levels, suggesting the paracrine effects to angiogenesis. These results suggested that the
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Tamaki, Tetsuro; Hirata, Maki; Nakajima, Nobuyuki; Saito, Kosuke; Hashimoto, Hiroyuki; Soeda, Shuichi; Uchiyama, Yoshiyasu; Watanabe, Masahiko
2016-01-01
Losses in vital functions of the somatic motor and sensory nervous system are induced by severe long-gap peripheral nerve transection injury. In such cases, autologous nerve grafts are the gold standard treatment, despite the unavoidable sacrifice of other healthy functions, whereas the prognosis is not always favorable. Here, we use human skeletal muscle-derived stem cells (Sk-SCs) to reconstitute the function after long nerve-gap injury. Muscles samples were obtained from the amputated legs from 9 patients following unforeseen accidents. The Sk-SCs were isolated using conditioned collagenase solution, and sorted as CD34+/45- (Sk-34) and CD34-/45-/29+ (Sk-DN/29+) cells. Cells were separately cultured/expanded under optimal conditions for 2 weeks, then injected into the athymic nude mice sciatic nerve long-gap model (7-mm) bridging an acellular conduit. After 8-12 weeks, active cell engraftment was observed only in the Sk-34 cell transplanted group, showing preferential differentiation into Schwann cells and perineurial/endoneurial cells, as well as formation of the myelin sheath and perineurium/endoneurium surrounding regenerated axons, resulted in 87% of numerical recovery. Differentiation into vascular cell lineage (pericyte and endothelial cells) were also observed. A significant tetanic tension recovery (over 90%) of downstream muscles following electrical stimulation of the sciatic nerve (at upper portion of the gap) was also achieved. In contrast, Sk-DN/29+ cells were completely eliminated during the first 4 weeks, but relatively higher numerical (83% vs. 41% in axon) and functional (80% vs. 60% in tetanus) recovery than control were observed. Noteworthy, significant increase in the formation of vascular networks in the conduit during the early stage (first 2 weeks) of recovery was observed in both groups with the expression of key factors (mRNA and protein levels), suggesting the paracrine effects to angiogenesis. These results suggested that the human Sk
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Quality Education in Idaho: A Case Study of Academic Achievement in Three High-Poverty Rural Schools
Brown, Christine
2017-01-01
The focus of this research is bridging the achievement gap for students living in poverty through quality education. Such a study is important because the percentage of students affected by poverty is increasing and the persistent gap in achievement evidences that the right to quality education for students in poverty is not being met. This is…
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Have the 'black clouds' cleared with new residency programme regulations?
Schissler, A J; Einstein, A J
2016-06-01
For decades, residents believed to work harder have been referred to as having a 'black cloud'. Residency training programmes recently instituted changes to improve physician wellness and achieve comparable clinical workload. All Internal Medicine residents in the internship class of 2014 at Columbia were surveyed to assess for the ongoing presence of 'black cloud' trainees. While some residents are still thought to have this designation, they did not have a greater workload when compared to their peers. © 2016 Royal Australasian College of Physicians.
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Black holes, magnetic fields and particle creation. [Quantum field theory
Energy Technology Data Exchange (ETDEWEB)
Gibbons, G W [Cambridge Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics
1976-10-01
Wald has given a classical argument suggesting that a rotating black hole immersed in a uniform magnetic field B will acquire a charge Q = 2JB where J is the angular momentum of the hole. The note contains a quantum field theoretic treatment of this process. For fields B greater than B/sub 0/ = 4 x 10/sup 13/ G the black hole will rapidly emit charged particles to achieve the equilibrium value. If B is less than the critical value the charge will remain zero.
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Szteinberg, Gabriela; Balicki, Scott; Banks, Gregory; Clinchot, Michael; Cullipher, Steven; Huie, Robert; Lambertz, Jennifer; Lewis, Rebecca; Ngai, Courtney; Weinrich, Melissa; Talanquer, Vicente; Sevian, Hannah
2014-01-01
Professional development that bridges gaps between educational research and practice is needed. However, bridging gaps can be difficult because teachers and educational researchers often belong to different Communities of Practice, as their activities, goals, and means of achieving those goals often differ. Meaningful collaboration among teachers…
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Boucher, Michael Lee, Jr.
2013-01-01
Despite a decade of concentration on closing the pervasive achievement gap in America, White students and Black students still attend schools with unequal results. Many strategies aimed at closing the gap exist, including increasing the number of African American teachers, but the majority of urban teachers are White, which will remain the case…
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Seasonal Dynamics of Academic Achievement Inequality by Socioeconomic Status and Race/Ethnicity
Quinn, David M.; Cooc, North; McIntyre, Joe; Gomez, Celia J.
2016-01-01
Early studies examining seasonal variation in academic achievement inequality generally concluded that socioeconomic test score gaps grew more over the summer than the school year, suggesting schools served as "equalizers." In this study, we analyze seasonal trends in socioeconomic status (SES) and racial/ethnic test score gaps using…
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Energy-gap spectroscopy of superconductors using a tunneling microscope
International Nuclear Information System (INIS)
Le Duc, H.G.; Kaiser, W.J.; Stern, J.A.
1987-01-01
A unique scanning tunneling microscope (STM) system has been developed for spectroscopy of the superconducting energy gap. High-resolution control of tunnel current and voltage allows for measurement of superconducting properties at tunnel resistance levels 10 2 --10 3 greater than that achieved in prior work. The previously used STM methods for superconductor spectroscopy are compared to those developed for the work reported here. Superconducting energy-gap spectra are reported for three superconductors, Pb, PbBi, and NbN, over a range of tunnel resistance. The measured spectra are compared directly to theory
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Quintessence background for 5D Einstein-Gauss-Bonnet black holes
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Sushant G. [University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Durban (South Africa); Centre for Theoretical Physics, New Delhi (India); Amir, Muhammed [Centre for Theoretical Physics, New Delhi (India); Maharaj, Sunil D. [University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Durban (South Africa)
2017-08-15
As we know that the Lovelock theory is an extension of the general relativity to the higher-dimensions, in this theory the first- and the second-order terms correspond to general relativity and the Einstein-Gauss-Bonnet gravity, respectively. We obtain a 5D black hole solution in Einstein-Gauss-Bonnet gravity surrounded by the quintessence matter, and we also analyze their thermodynamical properties. Owing to the quintessence corrected black hole, the thermodynamic quantities have also been corrected except for the black hole entropy, and a phase transition is achievable. The phase transition for the thermodynamic stability is characterized by a discontinuity in the specific heat at r = r{sub C}, with the stable (unstable) branch for r < (>) r{sub C}. (orig.)
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Bowleg, Lisa; Teti, Michelle; Massie, Jenné S.; Patel, Aditi; Malebranche, David J.; Tschann, Jeanne M.
2011-01-01
Research documents the link between traditional ideologies of masculinity and sexual risk among multi-ethnic male adolescents and White male college students, but similar research with Black heterosexual men is scarce. This exploratory study addressed this gap through six focus groups with 41 Black, low to middle income heterosexual men aged 19 to 51 years in Philadelphia, PA. Analyses highlighted two explicit ideologies of masculinity: that Black men should have sex with multiple women, often concurrently; and that Black men should not be gay or bisexual. Analyses also identified two implicit masculinity ideologies: the perception that Black heterosexual men cannot decline sex, even risky sex; and that women are primarily responsible for condom use. The study’s implications for HIV prevention with Black heterosexual men are discussed. PMID:21390949
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Brügmann, B.; Ghez, A. M.; Greiner, J.
2001-01-01
Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.
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GapBlaster-A Graphical Gap Filler for Prokaryote Genomes.
Directory of Open Access Journals (Sweden)
Pablo H C G de Sá
Full Text Available The advent of NGS (Next Generation Sequencing technologies has resulted in an exponential increase in the number of complete genomes available in biological databases. This advance has allowed the development of several computational tools enabling analyses of large amounts of data in each of the various steps, from processing and quality filtering to gap filling and manual curation. The tools developed for gap closure are very useful as they result in more complete genomes, which will influence downstream analyses of genomic plasticity and comparative genomics. However, the gap filling step remains a challenge for genome assembly, often requiring manual intervention. Here, we present GapBlaster, a graphical application to evaluate and close gaps. GapBlaster was developed via Java programming language. The software uses contigs obtained in the assembly of the genome to perform an alignment against a draft of the genome/scaffold, using BLAST or Mummer to close gaps. Then, all identified alignments of contigs that extend through the gaps in the draft sequence are presented to the user for further evaluation via the GapBlaster graphical interface. GapBlaster presents significant results compared to other similar software and has the advantage of offering a graphical interface for manual curation of the gaps. GapBlaster program, the user guide and the test datasets are freely available at https://sourceforge.net/projects/gapblaster2015/. It requires Sun JDK 8 and Blast or Mummer.
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Harper, Shaun R.
2015-01-01
In this article, Shaun R. Harper investigates how Black undergraduate men respond to and resist the internalization of racist stereotypes at predominantly White colleges and universities. Prior studies consistently show that racial stereotypes are commonplace on many campuses, that their effects are usually psychologically and academically…
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The phase structure of higher-dimensional black rings and black holes
International Nuclear Information System (INIS)
Emparan, Roberto; Harmark, Troels; Niarchos, Vasilis; Obers, Niels A.; RodrIguez, Maria J.
2007-01-01
We construct an approximate solution for an asymptotically flat, neutral, thin rotating black ring in any dimension D ≥ 5 by matching the near-horizon solution for a bent boosted black string, to a linearized gravity solution away from the horizon. The rotating black ring solution has a regular horizon of topology S 1 x S D-3 and incorporates the balancing condition of the ring as a zero-tension condition. For D = 5 our method reproduces the thin ring limit of the exact black ring solution. For D ≥ 6 we show that the black ring has a higher entropy than the Myers-Perry black hole in the ultra-spinning regime. By exploiting the correspondence between ultra-spinning black holes and black membranes on a two-torus, we take steps towards qualitatively completing the phase diagram of rotating blackfolds with a single angular momentum. We are led to propose a connection between MP black holes and black rings, and between MP black holes and black Saturns, through merger transitions involving two kinds of 'pinched' black holes. More generally, the analogy suggests an infinite number of pinched black holes of spherical topology leading to a complicated pattern of connections and mergers between phases
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Higher spin black holes with soft hair
Energy Technology Data Exchange (ETDEWEB)
Grumiller, Daniel [Institute for Theoretical Physics, TU Wien,Wiedner Hauptstrasse 8-10/136, Vienna, A-1040 (Austria); Pérez, Alfredo [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile); Prohazka, Stefan [Institute for Theoretical Physics, TU Wien,Wiedner Hauptstrasse 8-10/136, Vienna, A-1040 (Austria); Tempo, David; Troncoso, Ricardo [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile)
2016-10-21
We construct a new set of boundary conditions for higher spin gravity, inspired by a recent “soft Heisenberg hair”-proposal for General Relativity on three-dimensional Anti-de Sitter space. The asymptotic symmetry algebra consists of a set of affine û(1) current algebras. Its associated canonical charges generate higher spin soft hair. We focus first on the spin-3 case and then extend some of our main results to spin-N, many of which resemble the spin-2 results: the generators of the asymptotic W{sub 3} algebra naturally emerge from composite operators of the û(1) charges through a twisted Sugawara construction; our boundary conditions ensure regularity of the Euclidean solutions space independently of the values of the charges; solutions, which we call “higher spin black flowers”, are stationary but not necessarily spherically symmetric. Finally, we derive the entropy of higher spin black flowers, and find that for the branch that is continuously connected to the BTZ black hole, it depends only on the affine purely gravitational zero modes. Using our map to W-algebra currents we recover well-known expressions for higher spin entropy. We also address higher spin black flowers in the metric formalism and achieve full consistency with previous results.
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On the Charter Question: Black Marxism and Black Nationalism
Stern, Mark; Hussain, Khuram
2015-01-01
This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…
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"Be Real Black for Me": Imagining BlackCrit in Education
Dumas, Michael J.; ross, kihana miraya
2016-01-01
The authors put forward a theorization of a Black Critical Theory, or what might be called BlackCrit, within, and in response to, Critical Race Theory, and then outline ways that BlackCrit in education helps us to more incisively analyze how the specificity of (anti)blackness matters in explaining how Black bodies become marginalized, disregarded,…
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International Nuclear Information System (INIS)
Blandford, R.D.; Thorne, K.S.
1979-01-01
Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)
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Economic Development of the Black Sea Riparian Countries during 2004-2012
Directory of Open Access Journals (Sweden)
Romeo Bosneagu
2014-05-01
Full Text Available The Black Sea is politically divided between the European Union, countries aspiring to join the EU and the Russian Federation. From an economic perspective, the area has a huge potential for development and is “claimed” by the same political actors. In 1992, BSEC (Black Sea Economic Cooperation was formed and it includes, along with the six riparian countries, eight countries in order to meet their economic power in order to achieve regional development. In the period 2004-2012 the economy Black Sea countries experienced strongly fluctuated, which was strongly connected to the global economy, the inflow of capital in the region and the influence of the global economic crisis.
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PAMAM templated N,Pt co-doped TiO2 for visible light photodegradation of brilliant black.
Nzaba, Sarre Kadia Myra; Ntsendwana, Bulelwa; Mamba, Bhekie Brilliance; Kuvarega, Alex Tawanda
2018-05-01
This study examined the photocatalytic degradation of an azo dye brilliant black (BB) using non-metal/metal co-doped TiO 2 . N,Pt co-doped TiO 2 photocatalysts were prepared by a modified sol-gel method using amine-terminated polyamidoamine dendrimer generation 0 (PG0) as a template and source of nitrogen. Structural, morphological, and textural properties were evaluated using scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM/EDX), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), Raman spectroscopy (RS), photoluminescence (PL) and ultra-violet/visible spectroscopy (UV-Vis). The synthesized photocatalysts exhibited lower band gap energies as compared to the Degussa P-25, revealing a red shift in band gap towards the visible light absorption region. Photocatalytic activity of N,Pt co-doped TiO 2 was measured by the reaction of photocatalytic degradation of BB dye. Enhanced photodegradation efficiency of BB was achieved after 180-min reaction time with an initial concentration of 50 ppm. This was attributed to the rod-like shape of the materials, larger surface area, and enhanced absorption of visible light induced by N,Pt co-doping. The N,Pt co-doped TiO 2 also exhibited pseudo-first-order kinetic behavior with half-life and rate constant of 0.37 and 0.01984 min -1 , respectively. The mechanism of the photodegradation of BB under the visible light irradiation was proposed. The obtained results prove that co-doping of TiO 2 with N and Pt contributed to the enhanced photocatalytic performances of TiO 2 for visible light-induced photodegradation of organic contaminants for environmental remediation. Therefore, this work provides a new approach to the synthesis of PAMAM templated N,Pt co-doped TiO 2 for visible light photodegradation of brilliant black.
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Noncommutative geometry inspired Einstein–Gauss–Bonnet black holes
Ghosh, Sushant G.
2018-04-01
Low energy limits of a string theory suggests that the gravity action should include quadratic and higher-order curvature terms, in the form of dimensionally continued Gauss–Bonnet densities. Einstein–Gauss–Bonnet is a natural extension of the general relativity to higher dimensions in which the first and second-order terms correspond, respectively, to general relativity and Einstein–Gauss–Bonnet gravity. We obtain five-dimensional (5D) black hole solutions, inspired by a noncommutative geometry, with a static spherically symmetric, Gaussian mass distribution as a source both in the general relativity and Einstein–Gauss–Bonnet gravity cases, and we also analyzes their thermodynamical properties. Owing the noncommutative corrected black hole, the thermodynamic quantities have also been modified, and phase transition is shown to be achievable. The phase transitions for the thermodynamic stability, in both the theories, are characterized by a discontinuity in the specific heat at r_+=rC , with the stable (unstable) branch for r ) rC . The metric of the noncommutative inspired black holes smoothly goes over to the Boulware–Deser solution at large distance. The paper has been appended with a calculation of black hole mass using holographic renormalization.
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Maylor, Uvanney
2014-01-01
This book is designed to challenge dominant educational discourses on the underachievement of Black children and to engender new understandings in initial teacher education (ITE) about Black children's education and achievement. Based in empirical case study work and theoretical insights drawn from Bourdieu, hooks, Freire, and Giroux, Maylor calls…
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Combating “I Hate This Stupid Book!”: Black Males and Critical Literacy
Wood, Summer; Jocius, Robin
2013-01-01
Too often, instruction designed to improve literacy achievement for black male readers and writers focuses on skill-based learning, ignoring cultural, social, and personal development. This article calls for the use of critical literacy strategies with African American male students, which can raise expectations for academic achievement by…
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NASA's Chandra Finds Black Holes Are "Green"
2006-04-01
the cavities. "If a car was as fuel-efficient as these black holes, it could theoretically travel over a billion miles on a gallon of gas," said coauthor Christopher Reynolds of the University of Maryland, College Park. New details are given about how black hole engines achieve this extreme efficiency. Some of the gas first attracted to the black holes may be blown away by the energetic activity before it gets too near the black hole, but a significant fraction must eventually approach the event horizon where it is used with high efficiency to power the jets. The study also implies that matter flows towards the black holes at a steady rate for several million years. Chandra X-ray Images of Elliptical Galaxies Chandra X-ray Images of Elliptical Galaxies "These black holes are very efficient, but it also takes a very long time to refuel them," said Steve Allen who receives funding from the Office of Science of the Department of Energy. This new study shows that black holes are green in another important way. The energy transferred to the hot gas by the jets should keep hot gas from cooling, thereby preventing billions of new stars from forming. This will place limits on the growth of the largest galaxies, and prevent galactic sprawl from taking over the neighborhood. These results will appear in an upcoming issue of the Monthly Notices of the Royal Astronomical Society. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. Additional information and images can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov For information about NASA and agency programs on the Web, visit: http://www.nasa.gov
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Trends in Income-Related Gaps in Enrollment in Early Childhood Education: 1968 to 2013
Magnuson, Katherine; Waldfogel, Jane
2016-01-01
The academic achievement gap between children from the lowest- and highest-income families appears to have risen in recent decades in the United States. Such income-related disparities in academic skills are already present when children enter elementary school, suggesting that the explanation for changing gaps can be traced to changing…
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Robinson, Keith; Harris, Angel L
2013-12-01
Despite numerous studies on parental involvement in children's academic schooling, there is a dearth of knowledge on how parents respond specifically to inadequate academic performance. This study examines whether 1) racial differences exist in parenting philosophy for addressing inadequate achievement, 2) social class has implications for parenting philosophy, and 3) parents' philosophies are consequential for children's academic achievement. Using data from the Child Development Supplement (N=1041) to the Panel Study of Income Dynamics, we sort parents into two categories-those whose parenting repertoires for addressing poor achievement include punitive responses and those whose repertoires do not. We then determine whether racial differences exist between these categories and how various responses within the aforementioned categories are related to students' academic achievement. The findings show that white and black parents have markedly different philosophies on how to respond to inadequate performance, and these differences appear to impact children's achievement in dramatically different ways. Educators and policy makers should pay particular attention to how parents respond to inadequate achievement as imploring parents of inadequately performing students to be more involved without providing them with some guidance might exacerbate the problem.
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Customizing Laboratory Information Systems: Closing the Functionality Gap.
Gershkovich, Peter; Sinard, John H
2015-09-01
Highly customizable laboratory information systems help to address great variations in laboratory workflows, typical in Pathology. Often, however, built-in customization tools are not sufficient to add all of the desired functionality and improve systems interoperability. Emerging technologies and advances in medicine often create a void in functionality that we call a functionality gap. These gaps have distinct characteristics—a persuasive need to change the way a pathology group operates, the general availability of technology to address the missing functionality, the absence of this technology from your laboratory information system, and inability of built-in customization tools to address it. We emphasize the pervasive nature of these gaps, the role of pathology informatics in closing them, and suggest methods on how to achieve that. We found that a large number of the papers in the Journal of Pathology Informatics are concerned with these functionality gaps, and an even larger proportion of electronic posters and abstracts presented at the Pathology Informatics Summit conference each year deal directly with these unmet needs in pathology practice. A rapid, continuous, and sustainable approach to closing these gaps is critical for Pathology to provide the highest quality of care, adopt new technologies, and meet regulatory and financial challenges. The key element of successfully addressing functionality gaps is gap ownership—the ability to control the entire pathology information infrastructure with access to complementary systems and components. In addition, software developers with detailed domain expertise, equipped with right tools and methodology can effectively address these needs as they emerge.
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New observational constraints on the growth of the first supermassive black holes
International Nuclear Information System (INIS)
Treister, E.; Schawinski, K.; Volonteri, M.; Natarajan, P.
2013-01-01
We constrain the total accreted mass density in supermassive black holes at z > 6, inferred via the upper limit derived from the integrated X-ray emission from a sample of photometrically selected galaxy candidates. Studying galaxies obtained from the deepest Hubble Space Telescope images combined with the Chandra 4 Ms observations of the Chandra Deep Field-South, we achieve the most restrictive constraints on total black hole growth in the early universe. We estimate an accreted mass density <1000 M ☉ Mpc –3 at z ∼ 6, significantly lower than the previous predictions from some existing models of early black hole growth and earlier prior observations. These results place interesting constraints on early black hole growth and mass assembly by accretion and imply one or more of the following: (1) only a fraction of the luminous galaxies at this epoch contain active black holes; (2) most black hole growth at early epochs happens in dusty and/or less massive—as yet undetected—host galaxies; (3) there is a significant fraction of low-z interlopers in the galaxy sample; (4) early black hole growth is radiatively inefficient, heavily obscured, and/or due to black hole mergers as opposed to accretion; or (5) the bulk of the black hole growth occurs at late times. All of these possibilities have important implications for our understanding of high-redshift seed formation models.
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Exploring cross-national differences in gender gaps in education
Langen, A.M.L. van; Bosker, R.J.; Dekkers, H.P.J.M.
2006-01-01
Although the participation rates of females in science, technology, engineering, and mathematics (or STEM) education is poor in most Western countries, considerable differences across countries exist as well. This may be due to differences in the so-called gender achievement gaps, that is, delays of
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The Nike-Black Brant V development program
Sevier, H.; Payne, B.; Ott, R.; Montag, W.
1976-01-01
The Nike-Black Brant V represents a combined U.S.-Canadian program to achieve a 40 percent increase in apogee performance over that of the unboosted BBV, with minimum component modification and no meaningful increase in flight environment levels. The process of achieving these objectives is described, in particular optimization of sustainer coast period and roll history, and the techniques used to ensure good stage separation. Details of the structural test program and subsequent successful vehicle proving flight are provided. Basic performance data are preented, with an indication of the further potential offered by Terrier boost.
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International Nuclear Information System (INIS)
Mathur, Samir D
2012-01-01
The idea of holography in gravity arose from the fact that the entropy of black holes is given by their surface area. The holography encountered in gauge/gravity duality has no such relation however; the boundary surface can be placed at an arbitrary location in AdS space and its area does not give the entropy of the bulk. The essential issues are also different between the two cases: in black holes we get Hawking radiation from the 'holographic surface' which leads to the information issue, while in gauge/gravity duality there is no such radiation. To resolve the information paradox we need to show that there are real degrees of freedom at the horizon of the hole; this is achieved by the fuzzball construction. In gauge/gravity duality we have instead a field theory defined on an abstract dual space; there are no gravitational degrees of freedom at the holographic boundary. It is important to understand the relations and differences between these two notions of holography to get a full understanding of the lessons from the information paradox.
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Exploring South Africa’s ‘black diamonds’ at live music performances
Directory of Open Access Journals (Sweden)
Martinette Kruger
2014-08-01
Full Text Available Problem under investigation: This exploratory study fills a gap in the literature by profiling ‘black diamonds’, the South African up-and-coming middle-class market, at live music concerts. Design, methodology and approach: A destination-based survey at five concerts in South Africa in 2012 extracted a sample of 164 black diamond attendees from the rest of the audience. The attendance motives of this sample were used to identify different market segments within the sample. Findings and implications: Factor analysis identified five key motives and five key management factors for a memorable experience, and a cluster analysis found three types of black diamond concertgoers: Enthusiasts, Sentimentalists and Novices. The three clusters differed significantly in terms of their socio-demographic and behavioural characteristics, and especially in terms of what they regarded as important for a memorable experience at a live concert. These results will enable managers to package live concerts accordingly in order to develop this market in South Africa. The research emphasises that attendees at live concerts cannot be regarded as homogeneous in terms of their profiles, needs and preferences.
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String matching with variable length gaps
DEFF Research Database (Denmark)
Bille, Philip; Gørtz, Inge Li; Vildhøj, Hjalte Wedel
2012-01-01
primitive in computational biology applications. Let m and n be the lengths of P and T, respectively, and let k be the number of strings in P. We present a new algorithm achieving time O(nlogk+m+α) and space O(m+A), where A is the sum of the lower bounds of the lengths of the gaps in P and α is the total...... number of occurrences of the strings in P within T. Compared to the previous results this bound essentially achieves the best known time and space complexities simultaneously. Consequently, our algorithm obtains the best known bounds for almost all combinations of m, n, k, A, and α. Our algorithm...
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Kim, Jin Yi; Sim, Ho Hyung; Song, Sinae; Noh, Yeoung Ah; Lee, Hong Woon; Taik Kim, Hee
2018-03-01
Titanium dioxide (TiO2) is one of the representative ceramic materials containing photocatalyst, optic and antibacterial activity. The hydroxyl radical in TiO2 applies to the intensive oxidizing agent, hence TiO2 is suitable to use photocatalytic materials. Black TiO2was prepared through reduction of amorphous TiO2 conducting under H2 which leads to color changes. Its black color is proven that absorbs 100% light across the whole-visible light, drawing enhancement of photocatalytic property. In this study, we aimed to compare the photocatalytic activity of silver ion doped on TiO2(TiO2/Ag+) and silver ion doped on black TiO2(black TiO2/Ag+) under visible light range. TiO2/Ag+ was fabricated following steps. 1) TiO2 was synthesized by a sol-gel method from Titanium tetraisopropoxide (TTIP). 2) Then AgNO3 was added during an aging process step for silver ion doping on the surface of TiO2. Moreover, Black TiO2/Ag+ was obtained same as TiO2/Ag+ except for calcination under H2. The samples were characterized X-ray diffraction (XRD), UV-visible reflectance (UV-vis DRS), and Methylene Blue degradation test. XRD analysis confirmed morphology of TiO2. The band gap of black TiO2/Ag+ was confirmed (2.6 eV) through UV-vis DRS, which was lower than TiO2/Ag+ (2.9 eV). The photocatalytic effect was conducted by methylene blue degradation test. It demonstrated that black TiO2/Ag+ had a photocatalytic effect under UV light also visible light.
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Gap-Balancing versus Measured Resection Technique in Total Knee Arthroplasty: A Comparison Study.
Churchill, Jessica L; Khlopas, Anton; Sultan, Assem A; Harwin, Steven F; Mont, Michael A
2018-01-01
Proper femoral component alignment in the axial plane during total knee arthroplasty (TKA) depends on accurate bone cuts and soft tissue balancing. Two methods that are used to achieve this are "measured resection" and "gap balancing." However, a controversy exists as to which method is more accurate and leads to better outcomes. Therefore, the purpose of this study was to evaluate: (1) implant survivorship, (2) patient outcomes, (3) complications, and (4) radiographic analysis comparing patients who underwent TKA with either gap-balancing or measured resection techniques. A total of 214 consecutive patients (221 knees) underwent primary TKA by a single surgeon between 2011 and 2012. Component alignment was achieved by using measured resection in 116 knees and gap balancing was used in 105 knees. The patients had a mean age of 66 years (range, 44-86 years) and a mean body mass index of 32 kg/m 2 (range, 22-52 kg/m 2 ). Patient range-of-motion (ROM) and Knee Society (KS) function and pain scores, and radiographic assessment, were assessed preoperatively and postoperatively at ∼6 weeks, 3 months, 1 year, and then annually. The mean follow-up time was 3 years. A Kaplan-Meier's analysis was performed to calculate the survivorship. The aseptic survivorship was 98% in both the measured resection and gap-balancing groups. The mean ROM was not significantly different between the measured resection and gap-balancing groups (123 vs. 123 degrees, p = 0.990). There were no significant differences between the two groups in terms of the KS function scores (86 vs. 85 points, p = 0.829) or the KS pain scores (93 vs. 92 points, p = 0.425). Otherwise, the radiographic evaluation at latest follow-up did not demonstrate any evidence of progressive radiolucencies or loosening, of any prosthesis. The results of this study found that at a mean follow-up of 3 years, both the measured resection and gap-balancing techniques achieved excellent survivorship and
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Thomas, Pearl
The distinguishable black theatre in America, mirroring a distinguishable black experience, is an artistic product which demands audience involvement. Both the Afro-American oral tradition and the art of gesture are integral aspects of black theatre. In addition, the tragedy found black theatre is not tragedy in the classic sense, as blacks feel…
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Nonlinear Gompertz Curve Models of Achievement Gaps in Mathematics and Reading
Cameron, Claire E.; Grimm, Kevin J.; Steele, Joel S.; Castro-Schilo, Laura; Grissmer, David W.
2015-01-01
This study examined achievement trajectories in mathematics and reading from school entry through the end of middle school with linear and nonlinear growth curves in 2 large longitudinal data sets (National Longitudinal Study of Youth--Children and Young Adults and Early Childhood Longitudinal Study--Kindergarten Cohort [ECLS-K]). The S-shaped…
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Advanced infrared optically black baffle materials
International Nuclear Information System (INIS)
Seals, R.D.; Egert, C.M.; Allred, D.D.
1990-01-01
Infrared optically black baffle surfaces are an essential component of many advanced optical systems. All internal surfaces in advanced infrared optical sensors that require stray light management to achieve resolution are of primary concern in baffle design. Current industrial materials need improvements to meet advanced optical sensor systems requirements for optical, survivability, and endurability. Baffles are required to survive and operate in potentially severe environments. Robust diffuse-absorptive black surfaces, which are thermally and mechanically stable to threats of x-ray, launch, and in-flight maneuver conditions, with specific densities to allow an acceptable weight load, handleable during assembly, cleanable, and adaptive to affordable manufacturing, are required as optical baffle materials. In this paper an overview of recently developed advanced infrared optical baffle materials, requirements, manufacturing strategies, and the Optics MODIL (Manufacturing Operations Development and Integration Laboratory) Advanced Baffle Program are discussed
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Caged black holes: Black holes in compactified spacetimes. I. Theory
International Nuclear Information System (INIS)
Kol, Barak; Sorkin, Evgeny; Piran, Tsvi
2004-01-01
In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes
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Dirac gap-induced graphene quantum dot in an electrostatic potential
Giavaras, G.; Nori, Franco
2011-04-01
A spatially modulated Dirac gap in a graphene sheet leads to charge confinement, thus enabling a graphene quantum dot to be formed without the application of external electric and magnetic fields [G. Giavaras and F. Nori, Appl. Phys. Lett. 97, 243106 (2010)]. This can be achieved provided the Dirac gap has a local minimum in which the states become localized. In this work, the physics of such a gap-induced dot is investigated in the continuum limit by solving the Dirac equation. It is shown that gap-induced confined states couple to the states introduced by an electrostatic quantum well potential. Hence the region in which the resulting hybridized states are localized can be tuned with the potential strength, an effect which involves Klein tunneling. The proposed quantum dot may be used to probe quasirelativistic effects in graphene, while the induced confined states may be useful for graphene-based nanostructures.
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Antecol, Heather; Bedard, Kelly
2004-01-01
Labor market attachment differs significantly across young black, Mexican, and white men. Although it has long been agreed that potential experience is a poor proxy for actual experience for women, many view it as an acceptable approximation for men. Using the NLSY, this paper documents the substantial difference between potential and actual…
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Full-waveform inversion: Filling the gaps
Beydoun, Wafik B.
2015-09-01
After receiving an outstanding response to its inaugural workshop in 2013, SEG once again achieved great success with its 2015 SEG Middle East Workshop, “Full-waveform inversion: Filling the gaps,” which took place 30 March–1 April 2015 in Abu Dhabi, UAE. The workshop was organized by SEG, and its partner sponsors were Saudi Aramco (gold sponsor), ExxonMobil, and CGG. Read More: http://library.seg.org/doi/10.1190/tle34091106.1
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International Nuclear Information System (INIS)
Novikov, I.; Polnarev, A.
1981-01-01
Proves are searched for of the formation of the so-called primary black holes at the very origin of the universe. The black holes would weigh less than 10 13 kg. The formation of a primary black hole is conditional on strong fluctuations of the gravitational field corresponding roughly to a half of the fluctuation maximally permissible by the general relativity theory. Only big fluctuations of the gravitational field can overcome the forces of the hot gas pressure and compress the originally expanding matter into a black hole. Low-mass black holes have a temperature exceeding that of the black holes formed from stars. A quantum process of particle formation, the so-called evaporation takes place in the strong gravitational field of a black hole. The lower the mass of the black hole, the shorter the evaporation time. The analyses of processes taking place during the evaporation of low-mass primary black holes show that only a very small proportion of the total mass of the matter in the universe could turn into primary black holes. (M.D.)
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2012-11-26
... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...
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Discrimination of Black Ball-point Pen Inks by High Performance Liquid Chromatography (HPLC)
International Nuclear Information System (INIS)
Mohamed Izzharif Abdul Halim; Norashikin Saim; Rozita Osman; Halila Jasmani; Nurul Nadhirah Zainal Abidin
2013-01-01
In this study, thirteen types of black ball-point pen inks of three major brands were analyzed using high performance liquid chromatography (HPLC). Separation of the ink components was achieved using Bondapak C-18 column with gradient elution using water, ethanol and ethyl acetate. The chromatographic data obtained at wavelength 254.8 nm was analyzed using agglomerative hierarchical clustering (AHC) and principle component analysis (PCA). AHC was able to group the inks into three clusters. This result was supported by PCA, whereby distinct separation of the three different brands was achieved. Therefore, HPLC in combination with chemometric methods may be a valuable tool for the analysis of black ball-point pen inks for forensic purposes. (author)
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Strain sensitivity of band gaps of Sn-containing semiconductors
DEFF Research Database (Denmark)
Li, Hong; Castelli, Ivano Eligio; Thygesen, Kristian Sommer
2015-01-01
Tuning of band gaps of semiconductors is a way to optimize materials for applications within photovoltaics or as photocatalysts. One way to achieve this is through applying strain to the materials. We investigate the effect of strain on a range of Sn-containing semiconductors using density...
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Phase transition for black holes with scalar hair and topological black holes
International Nuclear Information System (INIS)
Myung, Yun Soo
2008-01-01
We study phase transitions between black holes with scalar hair and topological black holes in asymptotically anti-de Sitter spacetimes. As the ground state solutions, we introduce the non-rotating BTZ black hole in three dimensions and topological black hole with hyperbolic horizon in four dimensions. For the temperature matching only, we show that the phase transition between black hole with scalar hair (Martinez-Troncoso-Zanelli black hole) and topological black hole is second-order by using differences between two free energies. However, we do not identify what order of the phase transition between scalar and non-rotating BTZ black holes occurs in three dimensions, although there exists a possible decay of scalar black hole to non-rotating BTZ black hole
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From binary black hole simulation to triple black hole simulation
International Nuclear Information System (INIS)
Bai Shan; Cao Zhoujian; Han, Wen-Biao; Lin, Chun-Yu; Yo, Hwei-Jang; Yu, Jui-Ping
2011-01-01
Black hole systems are among the most promising sources for a gravitational wave detection project. Now, China is planning to construct a space-based laser interferometric detector as a follow-on mission of LISA in the near future. Aiming to provide some theoretical support to this detection project on the numerical relativity side, we focus on black hole systems simulation in this work. Considering the globular galaxy, multiple black hole systems also likely to exist in our universe and play a role as a source for the gravitational wave detector we are considering. We will give a progress report in this paper on our black hole system simulation. More specifically, we will present triple black hole simulation together with binary black hole simulation. On triple black hole simulations, one novel perturbational method is proposed.
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Sa, Baisheng; Li, Yan-Ling; Sun, Zhimei; Qi, Jingshan; Wen, Cuilian; Wu, Bo
2015-05-29
Artificial monolayer black phosphorus, so-called phosphorene, has attracted global interest with its distinguished anisotropic, optoelectronic, and electronic properties. Here, we unraveled the shear-induced direct-to-indirect gap transition and anisotropy diminution in phosphorene based on first-principles calculations. Lattice dynamic analysis demonstrates that phosphorene can sustain up to 10% applied shear strain. The bandgap of phosphorene experiences a direct-to- indirect transition when 5% shear strain is applied. The electronic origin of the direct-to-indirect gap transition from 1.54 eV at ambient conditions to 1.22 eV at 10% shear strain for phosphorene is explored. In addition, the anisotropy diminution in phosphorene is discussed by calculating the maximum sound velocities, effective mass, and decomposed charge density, which signals the undesired shear-induced direct-to-indirect gap transition in applications of phosphorene for electronics and optoelectronics. On the other hand, the shear-induced electronic anisotropy properties suggest that phosphorene can be applied as the switcher in nanoelectronic applications.
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Gene Circuit Analysis of the Terminal Gap Gene huckebein
Ashyraliyev, Maksat; Siggens, Ken; Janssens, Hilde; Blom, Joke; Akam, Michael; Jaeger, Johannes
2009-01-01
The early embryo of Drosophila melanogaster provides a powerful model system to study the role of genes in pattern formation. The gap gene network constitutes the first zygotic regulatory tier in the hierarchy of the segmentation genes involved in specifying the position of body segments. Here, we use an integrative, systems-level approach to investigate the regulatory effect of the terminal gap gene huckebein (hkb) on gap gene expression. We present quantitative expression data for the Hkb protein, which enable us to include hkb in gap gene circuit models. Gap gene circuits are mathematical models of gene networks used as computational tools to extract regulatory information from spatial expression data. This is achieved by fitting the model to gap gene expression patterns, in order to obtain estimates for regulatory parameters which predict a specific network topology. We show how considering variability in the data combined with analysis of parameter determinability significantly improves the biological relevance and consistency of the approach. Our models are in agreement with earlier results, which they extend in two important respects: First, we show that Hkb is involved in the regulation of the posterior hunchback (hb) domain, but does not have any other essential function. Specifically, Hkb is required for the anterior shift in the posterior border of this domain, which is now reproduced correctly in our models. Second, gap gene circuits presented here are able to reproduce mutants of terminal gap genes, while previously published models were unable to reproduce any null mutants correctly. As a consequence, our models now capture the expression dynamics of all posterior gap genes and some variational properties of the system correctly. This is an important step towards a better, quantitative understanding of the developmental and evolutionary dynamics of the gap gene network. PMID:19876378
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Surface geometry of 5D black holes and black rings
International Nuclear Information System (INIS)
Frolov, Valeri P.; Goswami, Rituparno
2007-01-01
We discuss geometrical properties of the horizon surface of five-dimensional rotating black holes and black rings. Geometrical invariants characterizing these 3D geometries are calculated. We obtain a global embedding of the 5D rotating black horizon surface into a flat space. We also describe the Kaluza-Klein reduction of the black ring solution (along the direction of its rotation) which, though it is nakedly singular, relates this solution to the 4D metric of a static black hole distorted by the presence of external scalar (dilaton) and vector ('electromagnetic') fields. The properties of the reduced black hole horizon and its embedding in E 3 are briefly discussed
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Feedback Limits to Maximum Seed Masses of Black Holes
International Nuclear Information System (INIS)
Pacucci, Fabio; Natarajan, Priyamvada; Ferrara, Andrea
2017-01-01
The most massive black holes observed in the universe weigh up to ∼10 10 M ⊙ , nearly independent of redshift. Reaching these final masses likely required copious accretion and several major mergers. Employing a dynamical approach that rests on the role played by a new, relevant physical scale—the transition radius—we provide a theoretical calculation of the maximum mass achievable by a black hole seed that forms in an isolated halo, one that scarcely merged. Incorporating effects at the transition radius and their impact on the evolution of accretion in isolated halos, we are able to obtain new limits for permitted growth. We find that large black hole seeds ( M • ≳ 10 4 M ⊙ ) hosted in small isolated halos ( M h ≲ 10 9 M ⊙ ) accreting with relatively small radiative efficiencies ( ϵ ≲ 0.1) grow optimally in these circumstances. Moreover, we show that the standard M • – σ relation observed at z ∼ 0 cannot be established in isolated halos at high- z , but requires the occurrence of mergers. Since the average limiting mass of black holes formed at z ≳ 10 is in the range 10 4–6 M ⊙ , we expect to observe them in local galaxies as intermediate-mass black holes, when hosted in the rare halos that experienced only minor or no merging events. Such ancient black holes, formed in isolation with subsequent scant growth, could survive, almost unchanged, until present.
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Townsend, P. K.
1997-01-01
This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usu...
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The Origin of Black Smock and White Collar
Hesapcioglu, Muhsin; Meseci Giorgetti, Filiz
2009-01-01
Although there are many empirical studies on the functions of school uniform, studies which focus on the origins of school uniform are neglected. Purpose of this study is to reveal historical origins of black smock and white collar. To achieve this purpose, a qualitative research method was adopted. As a result of the research, it was determined…
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Black silicon solar cells with black bus-bar strings
DEFF Research Database (Denmark)
Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io
2016-01-01
We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by maskless reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Four different methods to obtain blackened bus-bar strings were compared with respect to reflectance, and two of these methods (i.e., oxidized copper and etched solder) were used to fabricate functional allblack solar 9-cell panels. The black bus-bars (e.......g., by oxidized copper) have a reflectance below 3% in the entire visible wavelength range. The combination of black silicon cells and blackened bus-bars results in aesthetic, all-black panels based on conventional, front-contacted solar cells without compromising efficiency....
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The Achievement of Economically Disadvantaged Fifth Graders in Summer Enrichment Camp
Boulden, Laurie
2013-01-01
The achievement gap between economically disadvantaged students and their traditional counterparts has continued to be a problem in education. Based on cognitive constructivist theory and enrichment theory, the purpose of this study was to investigate the relationship between scores on a high-stakes achievement test and participation in a summer…
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High repetition rate burst-mode spark gap
International Nuclear Information System (INIS)
Faltens, A.; Reginato, L.; Hester, R.; Chesterman, A.; Cook, E.; Yokota, T.; Dexter, W.
1978-01-01
Results are presented on the design and testing of a pressurized gas blown spark gap switch capable of high repetition rates in a burst mode of operation. The switch parameters which have been achieved are as follows: 220-kV, 42-kA, a five pulse burst at 1-kHz, 12-ns risetime, 2-ns jitter at a pulse width of 50-ns
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Owusu-Kwarteng, Louise
2010-01-01
Research undertaken within the Sociology of Education frequently highlights concerns about the underachievement of Black students in education and, later, within the labour market. Yet, there are a number of shortcomings associated with research in this area. Firstly, there is a tendency to homogenise the achievement levels of all Black students. Thus observations made about the outcomes of African-Caribbean students are often applied to all other Black groups. When distinctions between Afric...
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Smith, William A.; Hung, Man; Franklin, Jeremy D.
2011-01-01
Black men's lives are racialized contradictions, They are told that contemporary educational and professional institutions--particularly historically White institutions (HWls)--are places where, through hard work, they can achieve the so-called American dream. However, for far too many Black men, HWIs represent racial climates that are replete…
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Fast local fragment chaining using sum-of-pair gap costs
DEFF Research Database (Denmark)
Otto, Christian; Hoffmann, Steve; Gorodkin, Jan
2011-01-01
, and rank the fragments to improve the specificity. Results: Here we present a fast and flexible fragment chainer that for the first time also supports a sum-of-pair gap cost model. This model has proven to achieve a higher accuracy and sensitivity in its own field of application. Due to a highly time...... alignment heuristics alone. By providing both the linear and the sum-of-pair gap cost model, a wider range of application can be covered. The software clasp is available at http://www.bioinf.uni-leipzig.de/Software/clasp/....
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Mourning, Erica
2014-01-01
Economically disadvantaged students are being outperformed by their non-disadvantaged peers in middle school mathematics. This problem is evidenced by 2013 data from a national middle school mathematics assessment which revealed an achievement gap of 27 scale score points. Closing this gap is important to schools with high populations of…
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Urban-Rural Excellence Gaps: Features, Factors, and Implications
Hernández-Torrano, Daniel
2018-01-01
The purpose of this study was to examine the presence of excellence gaps (i.e., differences between subgroups of students performing at the highest levels of achievement) in a sample of 563 students nominated as gifted by their teachers in urban, semi-urban, and rural settings in Spain. In general, the results suggested the existence of excellence…
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Magnet system optimization for segmented adaptive-gap in-vacuum undulator
Energy Technology Data Exchange (ETDEWEB)
Kitegi, C., E-mail: ckitegi@bnl.gov; Chubar, O.; Eng, C. [Energy Sciences Directorates, Brookhaven National Laboratory, Upton NY1 1973 (United States)
2016-07-27
Segmented Adaptive Gap in-vacuum Undulator (SAGU), in which different segments have different gaps and periods, promises a considerable spectral performance gain over a conventional undulator with uniform gap and period. According to calculations, this gain can be comparable to the gain achievable with a superior undulator technology (e.g. a room-temperature in-vacuum hybrid SAGU would perform as a cryo-cooled hybrid in-vacuum undulator with uniform gap and period). However, for reaching the high spectral performance, SAGU magnetic design has to include compensation of kicks experienced by the electron beam at segment junctions because of different deflection parameter values in the segments. We show that such compensation to large extent can be accomplished by using a passive correction, however, simple correction coils are nevertheless required as well to reach perfect compensation over a whole SAGU tuning range. Magnetic optimizations performed with Radia code, and the resulting undulator radiation spectra calculated using SRW code, demonstrating a possibility of nearly perfect correction, are presented.
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Distortion of Schwarzschild-anti-de Sitter black holes to black strings
International Nuclear Information System (INIS)
Tomimatsu, Akira
2005-01-01
Motivated by the existence of black holes with various topologies in four-dimensional spacetimes with a negative cosmological constant, we study axisymmetric static solutions describing any large distortions of Schwarzschild-anti-de Sitter black holes parametrized by the mass m. Under the approximation such that m is much larger than the anti-de Sitter radius, it is found that a cylindrically symmetric black string is obtained as a special limit of distorted spherical black holes. Such a prolonged distortion of the event horizon connecting a Schwarzschild-anti-de Sitter black hole to a black string is allowed without violating both the usual black hole thermodynamics and the hoop conjecture for the horizon circumference
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Nonviolent unitarization: basic postulates to soft quantum structure of black holes
Giddings, Steven B.
2017-12-01
A first-principles approach to the unitarity problem for black holes is systematically explored, based on the postulates of 1) quantum mechanics 2) the ability to approximately locally divide quantum gravitational systems into subsystems 3) correspondence with quantum field theory predictions for appropriate observers and (optionally) 4) universality of new gravitational effects. Unitarity requires interactions between the internal state of a black hole and its surroundings that have not been identified in the field theory description; correspondence with field theory indicates that these are soft. A conjectured information-theoretic result for information transfer between subsystems, partly motivated by a perturbative argument, then constrains the minimum coupling size of these interactions of the quantum atmosphere of a black hole. While large couplings are potentially astronomically observable, given this conjecture one finds that the new couplings can be exponentially small in the black hole entropy, yet achieve the information transfer rate needed for unitarization, due to the large number of black hole internal states. This provides a new possible alternative to arguments for large effects near the horizon. If universality is assumed, these couplings can be described as small, soft, state-dependent fluctuations of the metric near the black hole. Open questions include that of the more fundamental basis for such an effective picture.
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Edgar G. Ulmer’s Film The Black Cat: An Eighty-Year Retrospective
Directory of Open Access Journals (Sweden)
Ronald Duke Saltinski
2014-08-01
Full Text Available Director Edgar G. Ulmer’s film The Black Cat was a rare achievement in American horror cinema when released in 1934. Some eighty years afterwards in 2014 The Black Cat warrants revisiting as one of the most unique and revered horror films ever made. The Black Cat is German expressionist in character, perverse and morbid, portraying the post World War I gothic mind of Europe. The film encompasses the rage and revenge of that war with motifs of murder, narcotics, torture, necrophilia, incest, and Satanic rituals; all of which are witnessed by a young America couple who have innocently traveled into a nightmarish tragedy. Rarely has a film like The Black Cat so captured the mood of horror blended with an intellectual narrative, unique acting, modernist settings, and classical music. Paul A. Cantor said “The Black Cat was a triumph for Ulmer; many consider it one of the most sophisticated and powerful horror stories ever made” (p. 142. Years later The Black Cat would be characterized as an “art film,” and even “read as a piece of intellectual cinema” (Schwaab, p. 46.
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Gender, race & the veteran wage gap.
Vick, Brandon; Fontanella, Gabrielle
2017-01-01
This paper analyzes earnings outcomes of Iraq/Afghanistan-era veterans. We utilize the 2009-2013 American Community Survey and a worker-matching methodology to decompose wage differences between veteran and non-veteran workers. Among fully-employed, 25-40 year-olds, veteran workers make 3% less than non-veteran workers. While male veterans make 9% less than non-veterans, female and black veterans experience a wage premium (2% and 7% respectively). Decomposition of the earnings gap identifies some of its sources. Relatively higher rates of disability and lower rates of educational attainment serve to increase the overall wage penalty against veterans. However, veterans work less in low-paying occupations than non-veterans, serving to reduce the wage penalty. Finally, among male and white subgroups, non-veterans earn more in the top quintile due largely to having higher educational attainment and greater representation in higher-paying occupations, such as management. Copyright © 2016 Elsevier Inc. All rights reserved.
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Families or Schools? Explaining the Convergence in White and Black Academic Performance.
Cook, Michael D; Evans, William N
2000-01-01
Differences in test scores of white and black students have narrowed substantially over time, falling by one-half since 1970s. Some have speculated that this convergence is due to changes in family background or convergence in school quality. In this article we decompose the convergence in test scores into that portion due to changes in parental education, changes in school quality, and a narrowing of the within-school gap in test scores. Only about 25% of the overall convergence is attributa...
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Black LGB Identities and Perceptions of Same-Sex Marriage.
Lee PhD Canditate, Jess
2018-01-10
The 2015 SCOTUS ruling legalizing same-sex marriage was hailed as a universal victory for the lesbian, gay, and bisexual (LGB) community, but the pervasive support mobilized to achieve this goal may mask important dissension and inequality within the community. Specifically, how race may shape or perpetuate inequalities in the LGB community through same-sex marriage largely has been absent from the discussion. Focusing on the perceived impact of same-sex marriage in respondents' lives, I investigate the relationship between Black LGBs' perception of same-sex marriage legalization and their intersectional identities and community membership. Drawing from the 2010 Social Justice Sexuality Project survey, I explain the complexity of the attitudes of Black LGBs to the legalization of same-sex marriage and illustrate that (1) Black LGBs exhibit heterogeneous interpretation of the effects of same-sex marriage legalization on their lives based on their racial and sexual identities, and (2) same-sex marriage may provide Black LGBs the rationale to affirm their racial community membership as sexual minorities. This study pushes our understanding of the relationship between intersectional identities and individuals' perceptions of the self, identity-based community memberships, and social institutions.
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Energy Technology Data Exchange (ETDEWEB)
2017-04-25
Gap Resolution is a software package that was developed to improve Newbler genome assemblies by automating the closure of sequence gaps caused by repetitive regions in the DNA. This is done by performing the follow steps:1) Identify and distribute the data for each gap in sub-projects. 2) Assemble the data associated with each sub-project using a secondary assembler, such as Newbler or PGA. 3) Determine if any gaps are closed after reassembly, and either design fakes (consensus of closed gap) for those that closed or lab experiments for those that require additional data. The software requires as input a genome assembly produce by the Newbler assembler provided by Roche and 454 data containing paired-end reads.
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Directory of Open Access Journals (Sweden)
Angela Khristin Brown
2013-07-01
Full Text Available The migration of blacks in North America through slavery became united. The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life.
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Magnetized black holes and black rings in the higher dimensional dilaton gravity
International Nuclear Information System (INIS)
Yazadjiev, Stoytcho S.
2006-01-01
In this paper we consider magnetized black holes and black rings in the higher dimensional dilaton gravity. Our study is based on exact solutions generated by applying a Harrison transformation to known asymptotically flat black hole and black ring solutions in higher dimensional spacetimes. The explicit solutions include the magnetized version of the higher dimensional Schwarzschild-Tangherlini black holes, Myers-Perry black holes, and five-dimensional (dipole) black rings. The basic physical quantities of the magnetized objects are calculated. We also discuss some properties of the solutions and their thermodynamics. The ultrarelativistic limits of the magnetized solutions are briefly discussed and an explicit example is given for the D-dimensional magnetized Schwarzschild-Tangherlini black holes
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Quartz-Enhanced Photoacoustic Spectroscopy Sensor with a Small-Gap Quartz Tuning Fork
Directory of Open Access Journals (Sweden)
Yu-Fei Ma
2018-06-01
Full Text Available A highly sensitive quartz-enhanced photoacoustic spectroscopy (QEPAS sensor based on a custom quartz tuning fork (QTF with a small-gap of 200 μm was demonstrated. With the help of the finite element modeling (FEM simulation software COMSOL, the change tendency of the QEPAS signal under the influence of the laser beam vertical position and the length of the micro-resonator (mR were calculated theoretically. Water vapor (H2O was selected as the target analyte. The experimental results agreed well with those of the simulation, which verified the correctness of the theoretical model. An 11-fold signal enhancement was achieved with the addition of an mR with an optimal length of 5 mm in comparison to the bare QTF. Finally, the H2O-QEPAS sensor, which was based on a small-gap QTF, achieved a minimum detection limit (MDL of 1.3 ppm, indicating an improvement of the sensor performance when compared to the standard QTF that has a gap of 300 μm.
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Preliminary results from a numerical study on the appendix gap losses in a Stirling engine
DEFF Research Database (Denmark)
Andersen, Stig Kildegård; Carlsen, Henrik; Thomsen, Per Grove
2005-01-01
Analytical expressions for the losses in the displacer clearance gap, a.k.a. the appendix gap, have been refined during the last decades. But most real life Stirling engines violate the assumptions behind these expressions and hence the expressions may not be applicable. In this study the gap has...... been included directly into a one dimensional Stirling engine model. Practical aspects of the method, such as handling the moving wall in the gap while achieving an energy conserving model formulation and handling discontinuous derivatives in the equations, are discussed. A study on the convergence...... output of the engine....
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Ross, John A.; Scott, Garth; Bruce, Catherine D.
2012-01-01
Recent research demonstrates that in many countries gender differences in mathematics achievement have virtually disappeared. Expectancy-value theory and social cognition theory both predict that if gender differences in achievement have declined there should be a similar decline in gender differences in self-beliefs. Extant literature is…
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Framing African American Students' Success and Failure in Urban Settings: A Typology for Change
Lewis, Chance W.; James, Marlon; Hancock, Stephen; Hill-Jackson, Valerie
2008-01-01
Grounded in critical race theory, this article seeks to frame the ideological positions of success and failure for African American students in urban school settings. First, we revisit national data and research literature that illustrate the ongoing urban Black-White achievement gap. Second, the Matrix of Achievement Paradigms is shared in an…
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Forbidden energy band gap in diluted a-Ge{sub 1-x}Si{sub x}:N films
Energy Technology Data Exchange (ETDEWEB)
Guarneros, C.; Rebollo-Plata, B. [Posgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Lozada-Morales, R., E-mail: rlozada@fcfm.buap.mx [Posgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Espinosa-Rosales, J.E. [Posgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Portillo-Moreno, J. [Facultad de Ciencias Quimicas, Benemerita Universidad Autonoma de Puebla, Blvd. 14 Sur 6301, Col. San Manuel, 72570, Puebla (Mexico); Zelaya-Angel, O. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, PO Box 14-740, Mexico 07360 D.F. (Mexico)
2012-06-01
By means of electron gun evaporation Ge{sub 1-x}Si{sub x}:N thin films, in the entire range 0 {<=} x {<=} 1, were prepared on Si (100) and glass substrates. The initial vacuum reached was 6.6 Multiplication-Sign 10{sup -4} Pa, then a pressure of 2.7 Multiplication-Sign 10{sup -2} Pa of high purity N{sub 2} was introduced into the chamber. The deposition time was 4 min. Crucible-substrate distance was 18 cm. X-ray diffraction patterns indicate that all the films were amorphous (a-Ge{sub 1-x}Si{sub x}:N). The nitrogen concentration was of the order of 1 at% for all the films. From optical absorption spectra data and by using the Tauc method the energy band gap (E{sub g}) was calculated. The Raman spectra only reveal the presence of Si-Si, Ge-Ge, and Si-Ge bonds. Nevertheless, infrared spectra demonstrate the existence of Si-N and Ge-N bonds. The forbidden energy band gap (E{sub g}) as a function of x in the entire range 0 {<=} x {<=} 1 shows two well defined regions: 0 {<=} x {<=} 0.67 and 0.67 {<=} x {<=} 1, due to two different behaviors of the band gap, where for x > 0.67 exists an abruptly change of E{sub g}(x). In this case E{sub g}(x) versus x is different to the variation of E{sub g} in a-Ge{sub 1-x}Si{sub x} and a-Ge{sub 1-x}Si{sub x}:H. This fact can be related to the formation of Ge{sub 3}N{sub 4} and GeSi{sub 2}N{sub 4} when x {<=} 0.67, and to the formation of Si{sub 3}N{sub 4} and GeSi{sub 2}N{sub 4} for 0.67 {<=} x. - Highlights: Black-Right-Pointing-Pointer Nitrogen doped amorphous Ge{sub 1-x}Si{sub x} thin films are grown by electron gun technique. Black-Right-Pointing-Pointer Nitrogen atoms on E{sub g} of the a-Ge{sub 1-x}Si{sub x} films in the 0 Pound-Sign x Pound-Sign 1 range are analyzed. Black-Right-Pointing-Pointer Variation in 0 Pound-Sign x Pound-Sign 1 range shows a warped change of E{sub g} in 1.0 - 3.6 eV range. Black-Right-Pointing-Pointer The change in E{sub g}(x) behavior when x {approx} 0.67 was associated with Ge{sub 2}SiN{sub 4
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Feedback Limits to Maximum Seed Masses of Black Holes
Energy Technology Data Exchange (ETDEWEB)
Pacucci, Fabio; Natarajan, Priyamvada [Department of Physics, Yale University, P.O. Box 208121, New Haven, CT 06520 (United States); Ferrara, Andrea [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)
2017-02-01
The most massive black holes observed in the universe weigh up to ∼10{sup 10} M {sub ⊙}, nearly independent of redshift. Reaching these final masses likely required copious accretion and several major mergers. Employing a dynamical approach that rests on the role played by a new, relevant physical scale—the transition radius—we provide a theoretical calculation of the maximum mass achievable by a black hole seed that forms in an isolated halo, one that scarcely merged. Incorporating effects at the transition radius and their impact on the evolution of accretion in isolated halos, we are able to obtain new limits for permitted growth. We find that large black hole seeds ( M {sub •} ≳ 10{sup 4} M {sub ⊙}) hosted in small isolated halos ( M {sub h} ≲ 10{sup 9} M {sub ⊙}) accreting with relatively small radiative efficiencies ( ϵ ≲ 0.1) grow optimally in these circumstances. Moreover, we show that the standard M {sub •}– σ relation observed at z ∼ 0 cannot be established in isolated halos at high- z , but requires the occurrence of mergers. Since the average limiting mass of black holes formed at z ≳ 10 is in the range 10{sup 4–6} M {sub ⊙}, we expect to observe them in local galaxies as intermediate-mass black holes, when hosted in the rare halos that experienced only minor or no merging events. Such ancient black holes, formed in isolation with subsequent scant growth, could survive, almost unchanged, until present.
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The Black Lives Matter Movement and Historically Black Colleges and Universities
Gasman, Marybeth
2017-01-01
This article looks at the Black Lives Matter Movement and Historically Black Colleges and Universities. Historically Black Colleges and Universities (HBCUs) continue to play an important role in society. However, what the Black Lives Matter movement shows consistently is that predominantly White institutions need to change, to step up and embrace…
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Development of Multidimensional Gap Conductance model using Virtual Link Gap Element
Energy Technology Data Exchange (ETDEWEB)
Kim, Hyo Chan; Yang, Yong Sik; Kim, Dae Ho; Bang, Je Geon; Kim, Sun Ki; Koo, Yang Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2013-10-15
The gap conductance that determines temperature gradient between pellet and cladding can be quite sensitive to gap thickness. For instance, once the gap size increases up to several micrometers in certain region, difference of pellet surface temperatures increases up to 100 Kelvin. Therefore, iterative thermo-mechanical coupled analysis is required to solve temperature distribution throughout pellet and cladding. Recently, multidimensional fuel performance codes have been being developed in the advanced countries to evaluate thermal behavior of fuel for off normal conditions and DBA(design based accident) conditions using the Finite Element Method (FEM). FRAPCON-FRAPTRAN code system, which is well known as the verified and reliable code, incorporates 1D thermal module and multidimensional mechanical module. In this code, multidimensional gap conductance model is not applied. ALCYONE developed by CEA introduces equivalent heat convection coefficient that represents multidimensional gap conductance as a function of gap thickness. BISON, which is multidimensional fuel performance code developed by INL, owns multidimensional gap conductance model using projected thermal contact. In general, thermal contact algorithm is nonlinear calculation which is expensive approach numerically. The gap conductance model for multi-dimension is difficult issue in terms of convergence and nonlinearity because gap conductance is function of gap thickness which depends on mechanical analysis at each iteration step. In this paper, virtual link gap (VLG) element has been proposed to resolve convergence issue and nonlinear characteristic of multidimensional gap conductance. In terms of calculation accuracy and convergence efficiency, the proposed VLG model was evaluated. LWR fuel performance codes should incorporate thermo-mechanical loop to solve gap conductance problem, iteratively. However, gap conductance in multidimensional model is difficult issue owing to its nonlinearity and
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Dose optimization in pelvic radiography by air gap method on CR and DR systems – A phantom study
International Nuclear Information System (INIS)
Chan, C.T.P.; Fung, K.K.L.
2015-01-01
Objectives: This study aimed at investigating the feasibility of replacing the anti-scatter grid with an air gap at a pelvic radiographic examination in order to reduce patient dose while retaining diagnostic image quality. Methods: An anthropomorphic pelvis phantom was placed on a device that allowed the adjustment of different air gap thicknesses introduced between the phantom and the image receptor of Computed Radiography (CR) and Digital Radiography (DR) systems. Grid and non-grid images with different air gap thicknesses of both systems were produced. Ovary and testes doses were measured using thermoluminescent dosimeters. Radiographic quality of all images was rated by 5 experienced radiographers blindly using the Image Quality Score (IQS) and Visual Grading Analysis (VGA) systems. Results: Images of diagnostic quality were produced while the grid was replaced by a range of 0–25 cm air gap thickness in the pelvic radiographic examination. At non-grid examination with 10 cm air gap thickness, a maximum of relative dose reduction by 70.7% and 81.6% at CR; 68.6% and 79.4% at DR were achieved respectively at ovary and testes locations of the phantom as compared with their corresponding grid examinations. Conclusion: 10 cm was found to be the optimal air gap thickness at the tested pelvic examination. Effective dose was found to be reduced by 2 and 2.3 times respectively at the CR and DR examinations while the anti-scatter grid was replaced by 10 cm air gap. However, dose reduction effect by air gap method was found to be more pronounced in CR than in DR. - Highlights: • 10 cm air gap was found to be a substitute to replace grid in pelvic RANDO in CR/DR. • Over 68.6% of dose reduction effect were achieved at the ovary and testes regions. • Over 76.4% of reduction in effective dose were achieved at both the tested regions. • Dose reduction by air gap method was found to be more pronounced in CR than in DR
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International Nuclear Information System (INIS)
Arsiwalla, Xerxes D.; Verlinde, Erik P.
2010-01-01
We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.'s multicenter supersymmetric black hole solutions provides a supergravity description of such backgrounds within which a black hole can be trapped within a confined volume. This construction is realized by solving for a levitating black hole over a magnetic dipole base. We comment on how such a construction is akin to a mechanical levitron.
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Effect of anisotropy on the magnon energy gap in a two-layer ferromagnetic superlattice
International Nuclear Information System (INIS)
Qiu Rongke; Liang Jing; Li Qingfeng; Zhang Zhidong; Song Panpan; Hong Xiaomin
2009-01-01
The magnon energy bands or spectra in a two-layer ferromagnetic superlattice are studied. It is found that a modulated energy gap exists in the magnon energy band along K x direction perpendicular to the superlattice plane, which is different from the optical magnon gap at K x =0. The anisotropy, the spin quantum numbers and the interlayer exchange couplings all affect the magnon energy gap. If the anisotropy exists, there will be no acoustic energy branch in the system. There is a competition effect of the anisotropy and the spin quantum number on the magnon energy gap. The competition achieves a balance at the zero energy gap, at which the symmetry of the system is higher. The two energy spectra of the two-layer ferromagnetic superlattice are lowered with increasing temperature.
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Horowitz, Gary T.; Teukolsky, Saul A.
1998-01-01
Black holes are among the most intriguing objects in modern physics. Their influence ranges from powering quasars and other active galactic nuclei, to providing key insights into quantum gravity. We review the observational evidence for black holes, and briefly discuss some of their properties. We also describe some recent developments involving cosmic censorship and the statistical origin of black hole entropy.
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Bridging the gap: the roles of social capital and ethnicity in medical student achievement.
Vaughan, Suzanne; Sanders, Tom; Crossley, Nick; O'Neill, Paul; Wass, Val
2015-01-01
Within medical education, there is a discrepancy between the achievement level of White students and that of their ethnic minority peers. The processes underlying this disparity have not been adequately investigated or explained. This study utilises social network analysis to investigate the impact of relationships on medical student achievement by ethnicity, specifically by examining homophily (the tendency to interact with others in the same group) by ethnicity, age and role. Data from a cross-sectional social network study conducted in one UK medical school are presented and are analysed alongside examination records obtained from the medical school. Participants were sampled across the four hospital placement sites; a total of 158 medical students in their clinical phase (Years 3 and 4) completed the survey. The research was designed and analysed using social capital theory. Although significant patterns of ethnic and religious homophily emerged, no link was found between these factors and achievement. Interacting with problem-based learning (PBL) group peers in study-related activities, and having seniors in a wider academic support network were directly linked to better achievement. Students in higher academic quartiles were more likely to be named by members of their PBL group in study activities and to name at least one tutor or clinician in their network. Students from lower-achieving groups were least likely to have the social capital enabling, and resulting from, interactions with members of more expert social groups. Lower levels of the social capital that mediates interaction with peers, tutors and clinicians may be the cause of underperformance by ethnic minority students. Because of ethnic homophily, minority students may be cut off from potential and actual resources that facilitate learning and achievement. © 2014 John Wiley & Sons Ltd.
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Matthews, Karen A; Boylan, Jennifer M; Jakubowski, Karen P; Cundiff, Jenny M; Lee, Laisze; Pardini, Dustin A; Jennings, J Richard
2017-07-01
American Heart Association (AHA) developed a new metric to evaluate ideal cardiovascular health based on optimal levels of 7 cardiovascular risk factors and health behaviors. We evaluated the relationships of parenting characteristics and academic achievement in adolescence in relation to ideal cardiovascular health in midlife men. We measured cardiovascular risk factors in 171 Black and 136 White men and their ideal cardiovascular health score was constructed based on AHA guidelines. When the participants were 13-16 years old, annual measures of parent-child communication, positive relationship, parental monitoring, family cohesion, boys' involvement in family activities, and academic achievement were recorded and averaged. Confirmatory factor analysis of adolescent parenting measures revealed a single Parenting Composite. Multiple linear regressions showed a significant Race by Parenting Composite interaction term, β = -.19, p = .03; better parenting was significantly related to more ideal cardiovascular health in Blacks only, β = -.23, p = .004, which remained after adjustments for adolescent and adult socioeconomic status (SES). Academic achievement was related to ideal cardiovascular health, β = -.13, but was no longer significant after controls for adult SES. Adult SES was a strong correlate of ideal cardiovascular health in Black and White men. Black men exposed to positive parenting during adolescence had more ideal cardiovascular health based on AHA guidelines. Improving academic achievement in adolescence may indirectly benefit adult cardiovascular health through improving adult SES. This is the first study of adolescent family predictors of the extent of ideal cardiovascular health. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
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International Nuclear Information System (INIS)
Cherepashchuk, Anatolii M
2003-01-01
Methods and results of searching for stellar mass black holes in binary systems and for supermassive black holes in galactic nuclei of different types are described. As of now (June 2002), a total of 100 black hole candidates are known. All the necessary conditions Einstein's General Relativity imposes on the observational properties of black holes are satisfied for candidate objects available, thus further assuring the existence of black holes in the Universe. Prospects for obtaining sufficient criteria for reliably distinguishing candidate black holes from real black holes are discussed. (reviews of topical problems)
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Energy Technology Data Exchange (ETDEWEB)
Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)
2007-11-15
We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.
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Convergent use of RhoGAP toxins by eukaryotic parasites and bacterial pathogens.
Directory of Open Access Journals (Sweden)
Dominique Colinet
2007-12-01
Full Text Available Inactivation of host Rho GTPases is a widespread strategy employed by bacterial pathogens to manipulate mammalian cellular functions and avoid immune defenses. Some bacterial toxins mimic eukaryotic Rho GTPase-activating proteins (GAPs to inactivate mammalian GTPases, probably as a result of evolutionary convergence. An intriguing question remains whether eukaryotic pathogens or parasites may use endogenous GAPs as immune-suppressive toxins to target the same key genes as bacterial pathogens. Interestingly, a RhoGAP domain-containing protein, LbGAP, was recently characterized from the parasitoid wasp Leptopilina boulardi, and shown to protect parasitoid eggs from the immune response of Drosophila host larvae. We demonstrate here that LbGAP has structural characteristics of eukaryotic RhoGAPs but that it acts similarly to bacterial RhoGAP toxins in mammals. First, we show by immunocytochemistry that LbGAP enters Drosophila immune cells, plasmatocytes and lamellocytes, and that morphological changes in lamellocytes are correlated with the quantity of LbGAP they contain. Demonstration that LbGAP displays a GAP activity and specifically interacts with the active, GTP-bound form of the two Drosophila Rho GTPases Rac1 and Rac2, both required for successful encapsulation of Leptopilina eggs, was then achieved using biochemical tests, yeast two-hybrid analysis, and GST pull-down assays. In addition, we show that the overall structure of LbGAP is similar to that of eukaryotic RhoGAP domains, and we identify distinct residues involved in its interaction with Rac GTPases. Altogether, these results show that eukaryotic parasites can use endogenous RhoGAPs as virulence factors and that despite their differences in sequence and structure, eukaryotic and bacterial RhoGAP toxins are similarly used to target the same immune pathways in insects and mammals.
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Black hole critical phenomena without black holes
Indian Academy of Sciences (India)
large values of Ф, black holes do form and for small values the scalar field ... on the near side of the ridge ultimately evolve to form black holes while those configu- ... The inset shows a bird's eye view looking down on the saddle point.
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... medlineplus.gov/ency/article/002858.htm Black widow spider To use the sharing features on this page, please enable JavaScript. The black widow spider (Latrodectus) has a shiny black body with a ...
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School Sector and Student Achievement in the Era of Standards Based Reforms
Carbonaro, William; Covay, Elizabeth
2010-01-01
The authors examine whether standards based accountability reforms of the past two decades have closed the achievement gap among public and private high school students. They analyzed data from the Education Longitudinal Study (ELS) to examine sector differences in high school achievement in the era of standards based reforms. The authors found…
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English, Devin; Bowleg, Lisa; del Río-González, Ana Maria; Tschann, Jeanne M.; Agans, Robert; Malebranche, David J
2017-01-01
Objectives Although social science research has examined police and law enforcement-perpetrated discrimination against Black men using policing statistics and implicit bias studies, there is little quantitative evidence detailing this phenomenon from the perspective of Black men. Consequently, there is a dearth of research detailing how Black men’s perspectives on police and law enforcement-related stress predict negative physiological and psychological health outcomes. This study addresses these gaps with the qualitative development and quantitative test of the Police and Law Enforcement (PLE) scale. Methods In Study 1, we employed thematic analysis on transcripts of individual qualitative interviews with 90 Black men to assess key themes and concepts and develop quantitative items. In Study 2, we used 2 focus groups comprised of 5 Black men each (n=10), intensive cognitive interviewing with a separate sample of Black men (n=15), and piloting with another sample of Black men (n=13) to assess the ecological validity of the quantitative items. For study 3, we analyzed data from a sample of 633 Black men between the ages of 18 and 65 to test the factor structure of the PLE, as we all as its concurrent validity and convergent/discriminant validity. Results Qualitative analyses and confirmatory factor analyses suggested that a 5-item, 1-factor measure appropriately represented respondents’ experiences of police/law enforcement discrimination. As hypothesized, the PLE was positively associated with measures of racial discrimination and depressive symptoms. Conclusions Preliminary evidence suggests that the PLE is a reliable and valid measure of Black men’s experiences of discrimination with police/law enforcement. PMID:28080104
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Precision of jaw-closing movements for different jaw gaps.
Hellmann, Daniel; Becker, Georg; Giannakopoulos, Nikolaos N; Eberhard, Lydia; Fingerhut, Christopher; Rammelsberg, Peter; Schindler, Hans J
2014-02-01
Jaw-closing movements are basic components of physiological motor actions precisely achieving intercuspation without significant interference. The main purpose of this study was to test the hypothesis that, despite an imperfect intercuspal position, the precision of jaw-closing movements fluctuates within the range of physiological closing movements indispensable for meeting intercuspation without significant interference. For 35 healthy subjects, condylar and incisal point positions for fast and slow jaw-closing, interrupted at different jaw gaps by the use of frontal occlusal plateaus, were compared with uninterrupted physiological jaw closing, with identical jaw gaps, using a telemetric system for measuring jaw position. Examiner-guided centric relation served as a clinically relevant reference position. For jaw gaps ≤4 mm, no significant horizontal or vertical displacement differences were observed for the incisal or condylar points among physiological, fast, and slow jaw-closing. However, the jaw positions under these three closing conditions differed significantly from guided centric relation for nearly all experimental jaw gaps. The findings provide evidence of stringent neuromuscular control of jaw-closing movements in the vicinity of intercuspation. These results might be of clinical relevance to occlusal intervention with different objectives. © 2013 Eur J Oral Sci.
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Yeh, Stuart S.
2010-01-01
This article synthesizes findings regarding the development of competence and learned helplessness and factors influencing persistence and intrinsic motivation, suggests the process through which small differences in early achievement are magnified by the current structure of schools, and reviews evidence suggesting that the characteristics of a…
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Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge
2002-04-01
Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.
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Labor productivity and employment gaps in Sub-Saharan Africa.
McCullough, Ellen B
2017-02-01
Drawing on a new set of nationally representative, internationally comparable household surveys, this paper provides an overview of key features of structural transformation - labor allocation and labor productivity - in four African economies. New, micro-based measures of sector labor allocation and cross-sector productivity differentials describe the incentives households face when allocating their labor. These measures are similar to national accounts-based measures that are typically used to characterize structural change. However, because agricultural workers supply far fewer hours of labor per year than do workers in other sectors in all of the countries analyzed, productivity gaps shrink by half, on average, when expressed on a per-hour basis. Underlying the productivity gaps that are prominently reflected in national accounts data are large employment gaps, which call into question the productivity gains that laborers can achieve through structural transformation. Furthermore, agriculture's continued relevance to structural change in Sub-Saharan Africa is highlighted by the strong linkages observed between rural non-farm activities and primary agricultural production.
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Closing the Gap GEF Experiences in Global Energy Efficiency
Yang, Ming
2013-01-01
Energy efficiency plays and will continue to play an important role in the world to save energy and mitigate greenhouse gas (GHG) emissions. However, little is known on how much additional capital should be invested to ensure using energy efficiently as it should be, and very little is known which sub-areas, technologies, and countries shall achieve maximum greenhouse gas emissions mitigation per dollar of investment in energy efficiency worldwide. Analyzing completed and slowly moving energy efficiency projects by the Global Environment Facility during 1991-2010, Closing the Gap: GEF Experiences in Global Energy Efficiency evaluates impacts of multi-billion-dollar investments in the world energy efficiency. It covers the following areas: 1. Reviewing the world energy efficiency investment and disclosing the global energy efficiency gap and market barriers that cause the gap; 2. Leveraging private funds with public funds and other resources in energy efficiency investments; using...
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Leithead, Mark D; Anand, Madhur; Silva, Lucas C R
2010-12-01
Climate change is expected to promote migration of species. In ecotones, areas of ecological tension, disturbances may provide opportunities for some migrating species to establish in otherwise competitive environments. The size of and time since disturbance may determine the establishment ability of these species. We investigated gap dynamics of an old-growth red pine (Pinus resinosa Sol. ex Aiton) forest in the Great Lakes-St. Lawrence forest in northern Ontario, Canada, a transition zone between temperate and boreal forest. We investigated the effects of gaps of different sizes and ages on tree species abundance and basal area. Our results show that tree species from the temperate forest further south, such as red maple (Acer rubrum L.), red oak (Quercus rubra L.), and white pine (Pinus strobus L.), establish more often in large, old gaps; however, tree species that have more northern distributions, such as black spruce (Picea mariana Mill.), paper birch (Betula papyrifera Marsh.), and red pine show no difference in establishment ability with gap size or age. These differences in composition could not be attributed to autogenic succession. We conclude that treefall gaps in this forest facilitate the establishment of northward migrating species, potentially providing a pathway for future forest migration in response to recent changes in climate.
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Crawford, Jerry, II
2013-01-01
The digital divide has been described as the distance or gap in access to information based on race, ethnicity, income, education and geographical location. This study examined how freshmen and first-semester journalism and mass communications students at five Historically Black Colleges and Universities [HBCUs] have been able to bridge the…
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English, Devin; Bowleg, Lisa; Del Río-González, Ana Maria; Tschann, Jeanne M; Agans, Robert P; Malebranche, David J
2017-04-01
Although social science research has examined police and law enforcement-perpetrated discrimination against Black men using policing statistics and implicit bias studies, there is little quantitative evidence detailing this phenomenon from the perspective of Black men. Consequently, there is a dearth of research detailing how Black men's perspectives on police and law enforcement-related stress predict negative physiological and psychological health outcomes. This study addresses these gaps with the qualitative development and quantitative test of the Police and Law Enforcement (PLE) Scale. In Study 1, we used thematic analysis on transcripts of individual qualitative interviews with 90 Black men to assess key themes and concepts and develop quantitative items. In Study 2, we used 2 focus groups comprised of 5 Black men each (n = 10), intensive cognitive interviewing with a separate sample of Black men (n = 15), and piloting with another sample of Black men (n = 13) to assess the ecological validity of the quantitative items. For Study 3, we analyzed data from a sample of 633 Black men between the ages of 18 and 65 to test the factor structure of the PLE, as we all as its concurrent validity and convergent/discriminant validity. Qualitative analyses and confirmatory factor analyses suggested that a 5-item, 1-factor measure appropriately represented respondents' experiences of police/law enforcement discrimination. As hypothesized, the PLE was positively associated with measures of racial discrimination and depressive symptoms. Preliminary evidence suggests that the PLE is a reliable and valid measure of Black men's experiences of discrimination with police/law enforcement. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
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A new type of artificial structure to achieve broadband omnidirectional acoustic absorption
Zheng, L.-Y.
2013-10-18
We present a design for a two-dimensional omnidirectional acoustic absorber that can achieve 98.6% absorption of acoustic waves in water, forming an effective acoustic black hole. This artificial black hole consists of an absorptive core coated with layers of periodically distributed polymer cylinders embedded in water. Effective medium theory describes the response of the coating layers to the acoustic waves. The polymer parameters can be adjusted, allowing practical fabrication of the absorber. Since the proposed structure does not rely on resonances, it is applicable to broad bandwidths. The design might be extended to a variety of applications.
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A new type of artificial structure to achieve broadband omnidirectional acoustic absorption
Directory of Open Access Journals (Sweden)
Li-Yang Zheng
2013-10-01
Full Text Available We present a design for a two-dimensional omnidirectional acoustic absorber that can achieve 98.6% absorption of acoustic waves in water, forming an effective acoustic black hole. This artificial black hole consists of an absorptive core coated with layers of periodically distributed polymer cylinders embedded in water. Effective medium theory describes the response of the coating layers to the acoustic waves. The polymer parameters can be adjusted, allowing practical fabrication of the absorber. Since the proposed structure does not rely on resonances, it is applicable to broad bandwidths. The design might be extended to a variety of applications.
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Directory of Open Access Journals (Sweden)
Clancy Blair
Full Text Available Effective early education is essential for academic achievement and positive life outcomes, particularly for children in poverty. Advances in neuroscience suggest that a focus on self-regulation in education can enhance children's engagement in learning and establish beneficial academic trajectories in the early elementary grades. Here, we experimentally evaluate an innovative approach to the education of children in kindergarten that embeds support for self-regulation, particularly executive functions, into literacy, mathematics, and science learning activities. Results from a cluster randomized controlled trial involving 29 schools, 79 classrooms, and 759 children indicated positive effects on executive functions, reasoning ability, the control of attention, and levels of salivary cortisol and alpha amylase. Results also demonstrated improvements in reading, vocabulary, and mathematics at the end of kindergarten that increased into the first grade. A number of effects were specific to high-poverty schools, suggesting that a focus on executive functions and associated aspects of self-regulation in early elementary education holds promise for closing the achievement gap.
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Blair, Clancy; Raver, C Cybele
2014-01-01
Effective early education is essential for academic achievement and positive life outcomes, particularly for children in poverty. Advances in neuroscience suggest that a focus on self-regulation in education can enhance children's engagement in learning and establish beneficial academic trajectories in the early elementary grades. Here, we experimentally evaluate an innovative approach to the education of children in kindergarten that embeds support for self-regulation, particularly executive functions, into literacy, mathematics, and science learning activities. Results from a cluster randomized controlled trial involving 29 schools, 79 classrooms, and 759 children indicated positive effects on executive functions, reasoning ability, the control of attention, and levels of salivary cortisol and alpha amylase. Results also demonstrated improvements in reading, vocabulary, and mathematics at the end of kindergarten that increased into the first grade. A number of effects were specific to high-poverty schools, suggesting that a focus on executive functions and associated aspects of self-regulation in early elementary education holds promise for closing the achievement gap.
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Where there’s smoke, there’s fire – and black carbon. Black carbon is the sooty material emitted from combustion processes, including diesel engines and other sources that burn fossil fuels, biofuels, or biomass. This soot contributes to fine particulate matter,...
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[Research progress of larger flexion gap than extension gap in total knee arthroplasty].
Zhang, Weisong; Hao, Dingjun
2017-05-01
To summarize the progress of larger flexion gap than extension gap in total knee arthro-plasty (TKA). The domestic and foreign related literature about larger flexion gap than extension gap in TKA, and its impact factors, biomechanical and kinematic features, and clinical results were summarized. During TKA, to adjust the relations of flexion gap and extension gap is one of the key factors of successful operation. The biomechanical, kinematic, and clinical researches show that properly larger flexion gap than extension gap can improve both the postoperative knee range of motion and the satisfaction of patients, but does not affect the stability of the knee joint. However, there are also contrary findings. So adjustment of flexion gap and extension gap during TKA is still in dispute. Larger flexion gap than extension gap in TKA is a new joint space theory, and long-term clinical efficacy, operation skills, and related complications still need further study.
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Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Sunaga, Akihiro; Tsujimura, Takuya; Matsuda, Yasuhiro; Mano, Toshiaki
2017-08-01
A bipolar voltage reflects a thick musculature where formation of a transmural lesion may be hard to achieve. The purpose of this study was to explore the association between local bipolar voltage and conduction gap in patients with persistent atrial fibrillation (AF) who underwent atrial roof or septal linear ablation. This prospective observational study included 42 and 36 consecutive patients with persistent AF who underwent roof or septal linear ablations, respectively. After pulmonary vein isolation, left atrial linear ablations were performed, and conduction gap sites were identified and ablated after first-touch radiofrequency application. Conduction gap(s) after the first-touch roof and septal linear ablation were observed in 13 (32%) and 19 patients (53%), respectively. Roof and septal area voltages were higher in patients with conduction gap(s) than in those without (roof, 1.23 ± 0.77 vs 0.73 ± 0.42 mV, p = 0.010; septal, 0.96 ± 0.43 vs 0.54 ± 0.18 mV, p = 0.001). Trisected regional analyses revealed that the voltage was higher at the region with a conduction gap than at the region without. Complete conduction block across the roof and septal lines was not achieved in 3 (7%) and 6 patients (17%), respectively. Patients in whom a linear conduction block could not be achieved demonstrated higher ablation area voltage than those with a successful conduction block (roof, 1.91 ± 0.74 vs 0.81 ± 0.51 mV, p = 0.001; septal, 1.15 ± 0.56 vs 0.69 ± 0.31 mV, p = 0.006). In conclusion, a high regional bipolar voltage predicts failure to achieve conduction block after left atrial roof or septal linear ablation. In addition, the conduction gap was located at the preserved voltage area. Copyright © 2017 Elsevier Inc. All rights reserved.
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Rapidity gap survival in central exclusive diffraction: Dynamical mechanisms and uncertainties
International Nuclear Information System (INIS)
Strikman, Mark; Weiss, Christian
2009-01-01
We summarize our understanding of the dynamical mechanisms governing rapidity gap survival in central exclusive diffraction, pp -> p + H + p (H = high-mass system), and discuss the uncertainties in present estimates of the survival probability. The main suppression of diffractive scattering is due to inelastic soft spectator interactions at small pp impact parameters and can be described in a mean-field approximation (independent hard and soft interactions). Moderate extra suppression results from fluctuations of the partonic configurations of the colliding protons. At LHC energies absorptive interactions of hard spectator partons associated with the gg -> H process reach the black-disk regime and cause substantial additional suppression, pushing the survival probability below 0.01.
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Montgomery, Susanne; Herring, Patti; Yancey, Antronette; Beeson, Larry; Butler, Terry; Knutsen, Synnove; Sabate, Joan; Chan, Jacqueline; Preston-Martin, Susan; Fraser, Gary
2007-07-01
Few epidemiologic cohort studies on the etiology of chronic disease are powerful enough to distinguish racial and ethnic determinants from socioeconomic determinants of health behaviors and observed disease patterns. The Adventist Health Study-2 (AHS-2), with its large number of respondents and the variation in lifestyles of its target populations, promises to shed light on these issues. This paper focuses on some preliminary baseline analyses of responses from the first group of participants recruited for AHS-2. We administered a validated and pilot-tested questionnaire on various lifestyle practices and health outcomes to 56,754 respondents to AHS-2, comprising 14,376 non-Hispanic blacks and 42,378 non-Hispanic whites. We analyzed cross-sectional baseline data adjusted for age and sex and performed logistic regressions to test differences between responses from the two racial groups. In this Seventh-day Adventist (Adventist) cohort, blacks were less likely than whites to be lifelong vegetarians and more likely to be overweight or obese. Exercise levels were lower for blacks than for whites, but blacks were as likely as whites not to currently smoke or drink. Blacks reported higher rates of hypertension and diabetes than did whites but lower rates of high serum cholesterol, myocardial infarction, emphysema, and all cancers. After we eliminated skin cancer from the analysis, the age-adjusted prevalence of cancer remained significantly lower for black than for white women. The prevalence of prostate cancer was 47% higher for black men than for white men. The profile of health habits for black Adventists is better than that for blacks nationally. Given the intractable nature of many other contributors to health disparities, including racism, housing segregation, employment discrimination, limited educational opportunity, and poorer health care, the relative advantage for blacks of the Adventist lifestyle may hold promise for helping to close the gap in health status
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Graphene/black phosphorus heterostructured photodetector
Xu, Jiao; Song, Young Jae; Park, Jin-Hong; Lee, Sungjoo
2018-06-01
Graphene photodetectors exhibit a low photoresponsivity due to their weak light absorbance. In this study, we fabricated a graphene/black phosphorus (BP) heterostructure, in which the multilayer BP flake with a ∼0.3 eV direct band gap functions as an enhanced light-absorption material. Further, the photoexcited electrons are trapped in the trap states of the BP, which creates a photogating effect and causes holes to flow into the graphene layer driven by the built-in potential between BP and graphene. The photocarrier lifetime is therefore prolonged by trapping, and as a result of the high carrier mobility of graphene, the holes that transfer into the graphene channel can travel through the circuit before they recombine with trapped electrons. These combined effects result in a high photoresponsivity: 55.75 A/W at λ = 655 nm, 1.82 A/W at λ = 785 nm, and 0.66 A/W at λ = 980 nm.
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Dynamically generated gap from holography in the charged black brane with hyperscaling violation
Kuang, Xiao-Mei; Wang, Bin; Wu, Jian-Pin
2015-01-01
We holographically investigate the effects of a dipole coupling between a fermion field and a $U(1)$ gauge field on the dual fermionic sector in the charged gravity bulk with hyperscaling violation. We analytically study the features of the ultraviolet and infrared Green's functions of the dual fermionic system and we show that as the dipole coupling and the hyperscaling violation exponent are varied, the fluid possess Fermi, marginal Fermi, non-Fermi liquid phases and also an additional Mott insulating phase. We find that the increase of the hyperscaling violation exponent which effectively reduces the dimensionality of the system makes it harder for the Mott gap to be formed. We also show that the observed duality between zeros and poles in the presence of a dipole moment coupling still persists in theories with hyperscaling violation.
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"The Dreaded Black Triangle" - Orthodontics : The Choice
Directory of Open Access Journals (Sweden)
P Janardhanam
2010-01-01
The black triangle that resulted due to orthodontic treatment in a 15 year old female patient had been alleviated by using both orthodontic and periodontic means. This report explains the various treatment modalities that can be adopted to avoid embarrassing post-treatment results. Several methods of managing patients with gingival diastemas exist, but the interdisciplinary aspects of treatment must be emphasized to achieve best results. The orthodontist can play a significant role in helping to manage these cases.
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Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica
2016-01-01
Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.
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The Association of Minority Self-Rated Health with Black versus White Gentrification.
Gibbons, Joseph; Barton, Michael S
2016-12-01
There exists controversy as to the impact gentrification of cities has on the well-being of minorities. Some accuse gentrification of causing health disparities for disadvantaged minority populations residing in neighborhoods that are changing as a result of these socioeconomic shifts. Past scholarship has suggested that fears of displacement and social isolation associated with gentrification lead to poorer minority health. However, there is a lack of research that directly links gentrification to minority health outcomes. We address this gap with individual data from the 2008 Philadelphia Health Management Corporation's Southeastern Pennsylvania Household Health Survey and census tract data from the 2000 Decennial Census and the 2006-2010 American Community Survey. We implement logistic multilevel models to determine whether and how a resident's self-rated health is affected by gentrification of their neighborhoods. We find that while gentrification does have a marginal effect improving self-rated health for neighborhood residents overall, it leads to worse health outcomes for Blacks. Accounting for racial change, while gentrification leading to increases in White population has no measurable effect on minority health, "Black gentrification" leads to marginally worse health outcomes for Black respondents. These results demonstrate the limitations that improvements of neighborhood socioeconomic character have in offsetting minority health disparities.
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Does Class-Size Reduction Close the Achievement Gap? Evidence from TIMSS 2011
Li, Wei; Konstantopoulos, Spyros
2017-01-01
Policies about reducing class size have been implemented in the US and Europe in the past decades. Only a few studies have discussed the effects of class size at different levels of student achievement, and their findings have been mixed. We employ quantile regression analysis, coupled with instrumental variables, to examine the causal effects of…
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Lumpy AdS5× S5 black holes and black belts
International Nuclear Information System (INIS)
Dias, Óscar J.C.; Santos, Jorge E.; Way, Benson
2015-01-01
Sufficiently small Schwarzschild black holes in global AdS 5 ×S 5 are Gregory-Laflamme unstable. We construct new families of black hole solutions that bifurcate from the onset of this instability and break the full SO(6) symmetry group of the S 5 down to SO(5). These new “lumpy" solutions are labelled by the harmonics ℓ. We find evidence that the ℓ=1 branch never dominates the microcanonical/canonical ensembles and connects through a topology-changing merger to a localised black hole solution with S 8 topology. We argue that these S 8 black holes should become the dominant phase in the microcanonical ensemble for small enough energies, and that the transition to Schwarzschild black holes is first order. Furthermore, we find two branches of solutions with ℓ=2. We expect one of these branches to connect to a solution containing two localised black holes, while the other branch connects to a black hole solution with horizon topology S 4 ×S 4 which we call a “black belt”.
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The Health-Impaired Miner Under the Black Lung Legislation. Revised.
Clague, Ewan; And Others
The report reviews the administration of the Federal Coal Mine Health and Safety Act of 1969 with respect to coal workers' pneumoconiosis (black Lung) and analyzes the results. The objective of establishing and maintaining cleaner air in the mines has been substantially achieved by the Bureau of Mines inspection system. The second, which provided…
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Wijers, R.A.M.J.
1996-01-01
Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes
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Schwarzschild black holes as unipolar inductors: Expected electromagnetic power of a merger
International Nuclear Information System (INIS)
Lyutikov, Maxim
2011-01-01
The motion of a Schwarzschild black hole with velocity v 0 =β 0 c through a constant magnetic field B 0 in vacuum induces a component of the electric field along the magnetic field, generating a nonzero second Poincare electromagnetic invariant * F·F≠0. This will produce (e.g., via radiative effects and vacuum breakdown) an electric charge density of the order of ρ ind =B 0 β 0 /(2πeR G ), where R G =2GM/c 2 is the Schwarzschild radius and M is the mass of the black hole; the charge density ρ ind is similar to the Goldreich-Julian density. The magnetospheres of moving black holes resemble in many respects the magnetospheres of rotationally-powered pulsars, with pair formation fronts and outer gaps, where the sign of the induced charge changes. As a result, the black hole will generate bipolar electromagnetic jets each consisting of two counter-aligned current flows (four current flows total), each carrying an electric current of the order I≅eB 0 R G β 0 . The electromagnetic power of the jets is L≅(GM) 2 B 0 2 β 0 2 /c 3 ; for a particular case of merging black holes the resulting Poynting power is L≅(GM) 3 B 0 2 /(c 5 R), where R is the radius of the orbit. In addition, in limited regions near the horizon the first electromagnetic invariant changes sign, so that the induced electric field becomes larger than the magnetic field, E>B. As a result, there will be local dissipation of the magnetic field close to the horizon, within a region with the radial extent ΔR≅R G β 0 . The total energy loss from a system of merging black holes is a sum of two components with similar powers, one due to the rotation of space-time within the orbit, driven by the nonzero angular momentum in the system, and the other due to the linear motion of the black holes through the magnetic field. Since the resulting electrodynamics is in many respects similar to pulsars, merging black holes may generate coherent radio and high energy emission beamed approximately along the
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Directory of Open Access Journals (Sweden)
William Hansen
2014-11-01
Full Text Available Different kinds of omissions sometimes occur, or are perceived to occur, in traditional narratives and in tradition-inspired literature. A familiar instance is when a narrator realizes that he or she does not fully remember the story that he or she has begun to tell, and so leaves out part of it, which for listeners may possibly result in an unintelligible narrative. But many instances of narrative gap are not so obvious. From straightforward, objective gaps one can distinguish less-obvious subjective gaps: in many cases narrators do not leave out anything crucial or truly relevant from their exposition, and yet readers perceive gaps and take steps to fill them. The present paper considers four examples of subjective gaps drawn from ancient Greek literature (the Pandora myth, ancient Roman literature (the Pygmalion legend, ancient Hebrew literature (the Joseph legend, and early Christian literature (the Jesus legend. I consider the quite varied ways in which interpreters expand the inherited texts of these stories, such as by devising names, manufacturing motives, creating backstories, and in general filling in biographical ellipses. Finally, I suggest an explanation for the phenomenon of subjective gaps, arguing that, despite their variety, they have a single cause.
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Black Interpretation, Black American Literature, and Grey Audiences.
Washington, Earl M.
1981-01-01
Defines and illustrates language techniques used by Black authors writing to and for Blacks in the 1960s and 1970s. Suggests how language and theme barriers of such literature might be overcome in a contemporary integrated oral interpretation classroom. (PD)
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Directory of Open Access Journals (Sweden)
Monique Moultrie
2017-11-01
Full Text Available This article explores how conservative and progressive black Protestants interrogate the theological theme of the sacrality of black life through digital media. The innovations of religious media in black evangelical communities remain an understudied phenomenon in African American religion, making this an apt arena for further discovery. This current intervention into the study of African American Religion examines digital activism through examples of religious media produced by blacks for black audiences. This article begins its interrogation of the sacrality of black life by juxtaposing those who contend that Black Babies Matter as pro-birth-oriented, religiously motivated activists with those religious opponents asserting Black Lives Matter who present an intersectional pro-life approach. The comparison of views relies on womanist cultural analysis as its main methodology to analyze and interpret digital media and explore its ramifications for African American Religion.
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THE ECONOMY AND ENERGY OF THE BLACK SEA REGION
Directory of Open Access Journals (Sweden)
Maria-Floriana Popescu
2014-12-01
Full Text Available The Black Sea region has proved to be an emerging hub for Europe’s security and has experienced several changes and a great development at the beginning of the twenty-first century. This process is currently carried out, and has important implications for European security in a broader definition of the term - to achieve traditional military security, but also tackling other challenges at the address soft security issues, such as organized crime. Located at the crossroads of three regions of paramount importance - Europe, Middle East and Central Asia – the Black Sea region is a major transit area for energy and at the same time, an important source of asymmetric risks and outbreaks of conflicts. Therefore, analysing this region from an economical point of view, but not forgetting the energy security implications for this area, represents the main focus of this article, along with underlining the importance of various actors in the region and their actions’ impact on the future development of the Black Sea territory and surroundings.
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Band gap opening in silicene on MgBr2(0001) induced by Li and Na
Zhu, Jiajie
2014-11-12
Silicene consists of a monolayer of Si atoms in a buckled honeycomb structure and is expected to be well compatible with the current Si-based technology. However, the band gap is strongly influenced by the substrate. In this context, the structural and electronic properties of silicene on MgBr2(0001) modified by Li and Na are investigated by first-principles calculations. Charge transfer from silicene (substrate) to substrate (silicene) is found for substitutional doping (intercalation). As compared to a band gap of 0.01 eV on the pristine substrate, strongly enhanced band gaps of 0.65 eV (substitutional doping) and 0.24 eV (intercalation) are achieved. The band gap increases with the dopant concentration.
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International Nuclear Information System (INIS)
Penrose, R.
1980-01-01
Conditions for the formation of a black hole are considered, and the properties of black holes. The possibility of Cygnus X-1 as a black hole is discussed. Einstein's theory of general relativity in relation to the formation of black holes is discussed. (U.K.)
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Black Lives Matter: A Commentary on Racism and Public Health.
Jee-Lyn García, Jennifer; Sharif, Mienah Zulfacar
2015-08-01
The recent nonindictments of police officers who killed unarmed Black men have incited popular and scholarly discussions on racial injustices in our legal system, racialized police violence, and police (mis)conduct. What is glaringly absent is a public health perspective in response to these events. We aim to fill this gap and expand the current dialogue beyond these isolated incidents to a broader discussion of racism in America and how it affects the health and well-being of people of color. Our goal is not only to reiterate how salient structural racism is in our society, but how critical antiracist work is to the core goals and values of public health.
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Weyl holographic superconductor in the Lifshitz black hole background
International Nuclear Information System (INIS)
Mansoori, S. A. Hosseini; Mirza, B.; Mokhtari, A.; Dezaki, F. Lalehgani; Sherkatghanad, Z.
2016-01-01
We investigate analytically the properties of the Weyl holographic superconductor in the Lifshitz black hole background. We find that the critical temperature of the Weyl superconductor decreases with increasing Lifshitz dynamical exponent, z, indicating that condensation becomes difficult. In addition, it is found that the critical temperature and condensation operator could be affected by applying the Weyl coupling, γ. Moreover, we compute the critical magnetic field and investigate its dependence on the parameters γ and z. Finally, we show numerically that the Weyl coupling parameter γ and the Lifshitz dynamical exponent z together control the size and strength of the conductivity peak and the ratio of gap frequency over critical temperature ω_g/T_c.
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Weyl holographic superconductor in the Lifshitz black hole background
Energy Technology Data Exchange (ETDEWEB)
Mansoori, S. A. Hosseini [Department of Physics, Boston University,590 Commonwealth Ave., Boston, MA 02215 (United States); Department of Physics, Isfahan University of Technology,Isfahan 84156-83111 (Iran, Islamic Republic of); Mirza, B. [Department of Physics, Isfahan University of Technology,Isfahan 84156-83111 (Iran, Islamic Republic of); Mokhtari, A. [Department of Physics, Tarbiat Modares University,Tehran 14155-4838 (Iran, Islamic Republic of); Dezaki, F. Lalehgani; Sherkatghanad, Z. [Department of Physics, Isfahan University of Technology,Isfahan 84156-83111 (Iran, Islamic Republic of)
2016-07-21
We investigate analytically the properties of the Weyl holographic superconductor in the Lifshitz black hole background. We find that the critical temperature of the Weyl superconductor decreases with increasing Lifshitz dynamical exponent, z, indicating that condensation becomes difficult. In addition, it is found that the critical temperature and condensation operator could be affected by applying the Weyl coupling, γ. Moreover, we compute the critical magnetic field and investigate its dependence on the parameters γ and z. Finally, we show numerically that the Weyl coupling parameter γ and the Lifshitz dynamical exponent z together control the size and strength of the conductivity peak and the ratio of gap frequency over critical temperature ω{sub g}/T{sub c}.
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Weyl holographic superconductor in the Lifshitz black hole background
Mansoori, S. A. Hosseini; Mirza, B.; Mokhtari, A.; Dezaki, F. Lalehgani; Sherkatghanad, Z.
2016-07-01
We investigate analytically the properties of the Weyl holographic superconductor in the Lifshitz black hole background. We find that the critical temperature of the Weyl superconductor decreases with increasing Lifshitz dynamical exponent, z, indicating that condensation becomes difficult. In addition, it is found that the critical temperature and condensation operator could be affected by applying the Weyl coupling, γ. Moreover, we compute the critical magnetic field and investigate its dependence on the parameters γ and z. Finally, we show numerically that the Weyl coupling parameter γ and the Lifshitz dynamical exponent z together control the size and strength of the conductivity peak and the ratio of gap frequency over critical temperature ω g /T c .
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Black ringoids: spinning balanced black objects in d≥5 dimensions — the codimension-two case
International Nuclear Information System (INIS)
Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen
2015-01-01
We propose a general framework for the study of asymptotically flat black objects with k+1 equal magnitude angular momenta in d≥5 spacetime dimensions (with 0≤k≤[((d−5)/2)]). In this approach, the dependence on all angular coordinates but one is factorized, which leads to a codimension-two problem. This framework can describe black holes with spherical horizon topology, the simplest solutions corresponding to a class of Myers-Perry black holes. A different set of solutions describes balanced black objects with S"n"+"1×S"2"k"+"1 horizon topology. The simplest members of this family are the black rings (k=0). The solutions with k>0 are dubbed black ringoids. Based on the nonperturbative numerical results found for several values of (n,k), we propose a general picture for the properties and the phase diagram of these solutions and the associated black holes with spherical horizon topology: n=1 black ringoids repeat the k=0 pattern of black rings and Myers-Perry black holes in 5 dimensions, whereas n>1 black ringoids follow the pattern of higher dimensional black rings associated with ‘pinched’ black holes and Myers-Perry black holes.
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The Middle School Experience: Effects on the Math and Science Achievement of Adolescents with LD.
Anderman, Eric M.
1998-01-01
Using data from the National Education Longitudinal Study and applying hierarchical linear modeling, this study found a strong gap in achievement in math and science between adolescents with and without learning disabilities (LD). The gap was reduced for LD adolescents who did not make a school transition until at least ninth grade. (DB)
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Black theology in South Africa – A theology of human dignity and black identity
Directory of Open Access Journals (Sweden)
Timothy van Aarde
2016-08-01
Full Text Available Black theology in South Africa is still relevant 20 years after the apartheid regime ended. It is a theology that gave to Black South Africans human dignity and a black identity. Black theology in South Africa confronted the imbalances of power and abusive power structures through an affirmation of human dignity and the uniqueness of the identity of black people. The biblical narrative of the Exodus is a definitive narrative in American black theology and liberation theology in overcoming oppression understood as political victimisation. Black theology in South Africa is not primarily about power and economics but also about the rediscovery of human dignity and black identity and to a lesser extent about victimisation. A third generation of black theology in South Africa will gain impetus through a rediscovery of human dignity and identity as its core values instead of a Black American liberation theology of victimisation or a Marxist liberation theology of the eradication of all power or economic imbalances.
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International Nuclear Information System (INIS)
Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke
2009-01-01
Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair - degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.
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Gregory, Anne; Mosely, Pharmicia M.
2004-01-01
While the achievement gap between African American students and white and Asian students is discussed widely in the media (e.g. Schemo, 2003), the gap in discipline between African Americans and these groups has gained much less attention. Few studies have explored teacher processes that affect the over-representation of African American students…
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A Facile Approach to Prepare Black TiO2 with Oxygen Vacancy for Enhancing Photocatalytic Activity
Chen, Shihao; Xiao, Yang; Hu, Zhengfa; Zhao, Hui; Xie, Wei
2018-01-01
Black TiO2 has triggered worldwide research interest due to its excellent photocatalytic properties. However, the understanding of its structure–property relationships and a more effective, facile and versatile method to produce it remain great challenges. We have developed a facile approach to synthesize black TiO2 nanoparticles with significantly improved light absorption in the visible and infrared regions. The experimental results show that oxygen vacancies are the major factors responsible for black coloration. More importantly, our black TiO2 nanoparticles have no Ti3+ ions. These oxygen vacancies could introduce localized states in the bandgap and act as trap centers, significantly decreasing the electron–hole recombination. The photocatalytic decomposition of both rhodamine B and methylene blue demonstrated that, under ultraviolet light irradiation, better photocatalytic performance is achieved with our black TiO2 nanoparticles than with commercial TiO2 nanoparticles. PMID:29659500
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The Knowledge Gap Versus the Belief Gap and Abstinence-Only Sex Education.
Hindman, Douglas Blanks; Yan, Changmin
2015-08-01
The knowledge gap hypothesis predicts widening disparities in knowledge of heavily publicized public affairs issues among socioeconomic status groups. The belief gap hypothesis extends the knowledge gap hypothesis to account for knowledge and beliefs about politically contested issues based on empirically verifiable information. This analysis of 3 national surveys shows belief gaps developed between liberals and conservatives regarding abstinence-only sex education; socioeconomic status-based knowledge gaps did not widen. The findings partially support both belief gap and knowledge gap hypotheses. In addition, the unique contributions of exposure to Fox News, CNN, and MSNBC in this process were investigated. Only exposure to Fox News was linked to beliefs about abstinence-only sex education directly and indirectly through the cultivation of conservative ideology.
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On the Bioeconomic potential of the Black Sea
Gomoiu, Marian-Traian
2015-04-01
The paper is a plea for the need to engage in more intensive researches on the Black Sea region bioeconomy so that they should keep pace with the researches taking place in other European seas. Bioeconomy offers Europe a unique opportunity to address complex inter-connected challenges, while achieving economic growth. Bioeconomy refers to the set of economic activities relating to the invention, development, production and use of biological products and processes. According to the European Commission, bioeconomy can be found in societal challenge category entitled "Food security, sustainable agriculture and forestry, marine, maritime and inland water research, and the Bioeconomy" (http://ec.europa.eu/research/bioeconomy/h2020/index_en.htm); a transition is needed towards an optimal and renewable use of biological resources and towards sustainable primary production and processing systems. The author makes a brief overview of the European preoccupations concerning scientific research into bioeconomy and, equally, presents Romanian thinking in the field, launched several decades ago, but never applied and developed in practice. In 1933 Dr. Gr. Antipa, former outstanding student of Ernst Haeckel at Jena, expounded his conception of general biology and the biological structure of the Black Sea introducing the concepts of "biosociology" and "bioeconomy", drawing conclusions on the natural mechanism of fish production in this sea and specifying the determining factors in functioning. Antipa notes the lack of uniformity of the living conditions in the Black Sea and draws conclusions based on indices and faunal aspects found in different areas and at different depths: 1. The Black Sea, to an even greater extent than the Baltic Sea, with which it has some similarity both of them having a continuous surface and homogeneous appearance, is divided into more zones or biotypes, bounded horizontally and vertically - i.e. depending on areas and depths - each with distinct and well
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UH-60M Black Hawk Helicopter (UH-60M Black Hawk)
2016-12-01
Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-341 UH-60M Black Hawk Helicopter (UH-60M Black Hawk ) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 21, 2016 18:25:45 UNCLASSIFIED UH-60M Black Hawk December 2015 SAR March 21, 2016 18...Operational Requirements Document OSD - Office of the Secretary of Defense O&S - Operating and Support PAUC - Program Acquisition Unit Cost UH-60M Black Hawk
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Black American and Nigerian Pentecostalism: A Black Religious ...
African Journals Online (AJOL)
Black American and Nigerian Pentecostalism: A Black Religious Schizophrenia, 1910-2010. ... in American and African Pentecostalism as is related to social crisis, the dislocation of masses brought on by economic deprivation, urbanization, the break up of traditional society and consequence loss of traditional values.
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PTCR effect in carbon black/copolymer composites
International Nuclear Information System (INIS)
Costa, L.C.; Chakki, A.; Achour, M.E.; Graca, M.P.F.
2011-01-01
Some materials show an abrupt increase in resistivity when the temperature changes only over a few degrees. This phenomenon, known as PTCR effect (positive temperature coefficient of resistivity), has been largely studied in the last few years, due to its potential applications in industry. Particularly, it can be used in auto controlled heaters, temperature sensors, protection circuits and in security systems for power electronic circuits. In this work we present the study of the electrical properties of the percolating system carbon black particles filled with ethylene butylacrylate copolymer composite (EBA), in the temperature range from -100 to 100 o C and in frequencies between 10 Hz and 100 kHz. The PTCR effect was observed at temperatures slightly above the room temperature, for concentrations higher than that of the percolation critical concentration. The mechanism responsible for the change in resistivity, at this stage, is predominantly tunnelling, wherein the conductive filler particles are not in physical contact, and the electrons tunnel through the insulating gap between them. At low temperatures, such as below and close to the glass transition temperature, the DC conductivity obeys the Arrhenius law. The calculated activation energy values are independent of carbon black contents inside the copolymer matrix, suggesting that these particles do not interact significantly with the chain segments of the macromolecules in the EBA copolymer.
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PTCR effect in carbon black/copolymer composites
Energy Technology Data Exchange (ETDEWEB)
Costa, L.C., E-mail: kady@fis.ua.p [I3N and Physics Department, University of Aveiro, 3810-193 Aveiro (Portugal); Chakki, A.; Achour, M.E. [LASTID, Physics Department, Faculty of Sciences, Ibn Tofail University, BP 133, 14000 Kenitra (Morocco); Graca, M.P.F. [I3N and Physics Department, University of Aveiro, 3810-193 Aveiro (Portugal)
2011-01-15
Some materials show an abrupt increase in resistivity when the temperature changes only over a few degrees. This phenomenon, known as PTCR effect (positive temperature coefficient of resistivity), has been largely studied in the last few years, due to its potential applications in industry. Particularly, it can be used in auto controlled heaters, temperature sensors, protection circuits and in security systems for power electronic circuits. In this work we present the study of the electrical properties of the percolating system carbon black particles filled with ethylene butylacrylate copolymer composite (EBA), in the temperature range from -100 to 100 {sup o}C and in frequencies between 10 Hz and 100 kHz. The PTCR effect was observed at temperatures slightly above the room temperature, for concentrations higher than that of the percolation critical concentration. The mechanism responsible for the change in resistivity, at this stage, is predominantly tunnelling, wherein the conductive filler particles are not in physical contact, and the electrons tunnel through the insulating gap between them. At low temperatures, such as below and close to the glass transition temperature, the DC conductivity obeys the Arrhenius law. The calculated activation energy values are independent of carbon black contents inside the copolymer matrix, suggesting that these particles do not interact significantly with the chain segments of the macromolecules in the EBA copolymer.