Segregation as a multi-scalar phenomenon and its implications for neighborhood-scale research: the case of South Seattle 1990-2010.

PubMed

Fowler, Christopher S

Neighborhoods and neighborhood change are often at least implicitly understood in relation to processes taking place at scales both smaller than and larger than the neighborhood itself. Until recently our capacity to represent these multi-scalar processes with quantitative measures has been limited. Recent work on "segregation profiles" by Reardon and collaborators (Reardon et al., 2008, 2009) expands our capacity to explore the relationship between population measures and scale. With the methodological tools now available, we need a conceptual shift in how we view population measures in order to bring our theories and measures of neighborhoods into alignment. I argue that segregation can be beneficially viewed as multi-scalar ; not a value calculable at some 'correct' scale, but a continuous function with respect to scale. This shift requires new ways of thinking about and analyzing segregation with respect to scale that engage with the complexity of the multi-scalar measure. Using block level data for eight neighborhoods in Seattle, Washington I explore the implications of a multi-scalar segregation measure for understanding neighborhoods and neighborhood change from 1990 to 2010.

Residential Segregation and Racial Cancer Disparities: A Systematic Review.

PubMed

Landrine, Hope; Corral, Irma; Lee, Joseph G L; Efird, Jimmy T; Hall, Marla B; Bess, Jukelia J

2017-12-01

This paper provides the first review of empirical studies of segregation and black-white cancer disparities. We searched all years of PubMed (through May 2016) using these terms: racial segregation, residential segregation, neighborhood racial composition (first terms) and (second terms) cancer incidence, mortality, survival, stage at diagnosis, screening. The 17 (of 668) articles that measured both segregation and a cancer outcome were retained. Segregation contributed significantly to cancer and to racial cancer disparities in 70% of analyses, even after controlling for socioeconomic status and health insurance. Residing in segregated African-American areas was associated with higher odds of later-stage diagnosis of breast and lung cancers, higher mortality rates and lower survival rates from breast and lung cancers, and higher cumulative cancer risks associated with exposure to ambient air toxics. There were no studies of many types of cancer (e.g., cervical). Studies differed in their measure of segregation, and 40% used an invalid measure. Possible mediators of the segregation effect usually were not tested. Empirical analysis of segregation and racial cancer disparities is a recent area of research. The literature is limited to 17 studies that focused primarily on breast cancer. Studies differed in their measure of segregation, yet segregation nonetheless contributed to cancer and to racial cancer disparities in 70% of analyses. This suggests the need for further research that uses valid measures of segregation, examines a variety of types of cancers, and explores the variables that may mediate the segregation effect.

Exploring the segregating and mineralization-inducing capacities of cationic hydrophilic polymers for preparation of robust, multifunctional mesoporous hybrid microcapsules.

PubMed

Shi, Jiafu; Zhang, Wenyan; Wang, Xiaoli; Jiang, Zhongyi; Zhang, Shaohua; Zhang, Xiaoman; Zhang, Chunhong; Song, Xiaokai; Ai, Qinghong

2013-06-12

A facile approach to preparing mesoporous hybrid microcapsules is developed by exploring the segregating and mineralization-inducing capacities of cationic hydrophilic polymer. The preparation process contains four steps: segregation of cationic hydrophilic polymer during template formation, cross-linking of the segregated polymer, biomimetic mineralization within cross-linked polymer network, and removal of template to simultaneously generate capsule lumen and mesopores on the capsule wall. Poly(allylamine hydrochloride) (PAH) is chosen as the model polymer, its hydrophilicity renders the segregating capacity and spontaneous enrichment in the near-surface region of CaCO3 microspheres; its biopolyamine-mimic structure renders the mineralization-inducing capacity to produce titania from the water-soluble titanium(IV) precursor. Meanwhile, CaCO3 microspheres serve the dual templating functions in the formation of hollow lumen and mesoporous wall. The thickness of capsule wall can be controlled by changing the polymer segregating and cross-linking conditions, while the pore size on the capsule wall can be tuned by changing the template synthesizing conditions. The robust hybrid microcapsules exhibit desirable efficiency in enzymatic catalysis, wastewater treatment and drug delivery. This approach may open facile, generic, and efficient pathway to designing and preparing a variety of hybrid microcapsules with high and tunable permeability, good stability and multiple functionalities for a broad range of applications.

A SHORT SEQUENCE IMMEDIATELY UPSTREAM OF THE INTERNAL REPEAT ELEMENTS IS CRITICAL FOR KSHV LANA MEDIATED DNA REPLICATION AND IMPACTS EPISOME PERSISTENCE

PubMed Central

León Vázquez, Erika De; Juillard, Franceline; Rosner, Bernard; Kaye, Kenneth M.

2013-01-01

Kaposi’s sarcoma-associated herpesvirus LANA (1162 residues) mediates episomal persistence of viral genomes during latency. LANA mediates viral DNA replication and segregates episomes to daughter nuclei. A 59 residue deletion immediately upstream of the internal repeat elements rendered LANA highly deficient for DNA replication and modestly deficient for the ability to segregate episomes, while smaller deletions did not. The 59 amino acid deletion reduced LANA episome persistence by ~14-fold, while sequentially smaller deletions resulted in ~3-fold, or no deficiency. Three distinct LANA regions reorganized heterochromatin, one of which contains the deleted sequence, but the deletion did not abolish LANA’s ability to alter chromatin. Therefore, this work identifies a short internal LANA sequence that is critical for DNA replication, has modest effects on episome segregation, and substantially impacts episome persistence; this region may exert its effects through an interacting host cell protein(s). PMID:24314665

12 CFR 204.8 - International banking facilities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... banking facility or IBF means a set of asset and liability accounts segregated on the books and records of... notification shall include a statement of intention by the institution that it will comply with the rules of... operate an IBF. (f) Recordkeeping requirements. A depository institution shall segregate on its books and...

Death by Segregation: Does the Dimension of Racial Segregation Matter?

PubMed

Yang, Tse-Chuan; Matthews, Stephen A

2015-01-01

The county-level geographic mortality differentials have persisted in the past four decades in the United States (US). Though several socioeconomic factors (e.g., inequality) partially explain this phenomenon, the role of race/ethnic segregation, in general, and the different dimensions of segregation, more specifically, has been underexplored. Focusing on all-cause age-sex standardized US county-level mortality (2004-2008), this study has two substantive goals: (1) to understand whether segregation is a determinant of mortality and if yes, how the relationship between segregation and mortality varies by racial/ethnic dyads (e.g., white/black), and (2) to explore whether different dimensions of segregation (i.e., evenness, exposure, concentration, centralization, and clustering) are associated with mortality. A third goal is methodological: to assess whether spatial autocorrelation influences our understanding of the associations between the dimensions of segregation and mortality. Race/ethnic segregation was found to contribute to the geographic mortality disparities. Moreover, the relationship with mortality differed by both race/ethnic group and the dimension of segregation. Specifically, white/black segregation is positively related to mortality, whereas the segregation between whites and non-black minorities is negatively associated with mortality. Among the five dimensions of segregation, evenness and exposure are more strongly related to mortality than other dimensions. Spatial filtering approaches also identified six unique spatial patterns that significantly affect the spatial distribution of mortality. These patterns offer possible insights that help identify omitted variables related to the persistent patterning of mortality in the US.

Gender-Role Identity, Attitudes toward Marriage, and Gender-Segregated School Backgrounds.

ERIC Educational Resources Information Center

Katsurada, Emiko; Sugihara, Yoko

2002-01-01

Investigated the relationship between Japanese college students' gender role identity and attitudes toward marriage, exploring the effects of gender-segregated school backgrounds on gender role identity and attitudes toward marriage. Women without any coeducational school background had relatively strong masculinity and desired to marry at older…

Income Segregation between School Districts and Inequality in Students' Achievement

ERIC Educational Resources Information Center

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…

Choice without Equity: Charter School Segregation

ERIC Educational Resources Information Center

Frankenberg, Erica; Siegel-Hawley, Genevieve; Wang, Jia

2011-01-01

The political popularity of charter schools is unmistakable. This article explores the relationship between charter schools and segregation across the country, in 40 states, the District of Columbia, and several dozen metropolitan areas with large enrollments of charter school students in 2007-08. The descriptive analysis of the charter school…

Gender and Specialty in Business Management Education

ERIC Educational Resources Information Center

Hunt, Gerald; Song, Fei

2013-01-01

Undergraduate university enrolment in Canada is characterized by a higher proportion of women to men, with a pattern of gender segregation across some disciplines. Within some disciplines, there is also a pattern of internal sex segregation whereby women and men still sort themselves into gendered sub-fields, a pattern that is particularly evident…

Ability Grouping, Segregation and Civic Competences among Adolescents. Research Briefing No. 76

ERIC Educational Resources Information Center

Janmaat, Jan Germen

2014-01-01

This research examines the linkages between ability grouping, classroom social and ethnic segregation, and civic competences (understood here as referring to attitudes and behaviours as well as knowledge and skills). It does so by analysing data from the International Association for the Evaluation of Educational Achievement (IEA) Civic Education…

Implications of Income-Based School Assignment Policies for Racial School Segregation

ERIC Educational Resources Information Center

Reardon, Sean F.; Yun, John T.; Kurlaender, Michal

2006-01-01

A number of public school districts in the United States have adopted income-based integration policies--policies that use measures of family income or socioeconomic status--in determining school assignment. Some scholars and policymakers contend that such policies will also reduce racial segregation. In this article this assumption is explored by…

Race (and Space) Matters: Exploring Residential Segregation to Introduce Geography in an Interdisciplinary Curriculum

ERIC Educational Resources Information Center

O'Brien, William E.

2007-01-01

This article discusses a class project on residential segregation in Florida's metropolitan areas for which students analyzed trends regarding African Americans relative to white populations using data from 1980 to 2000. The project provided a means of teaching the importance of geographical perspectives to nongeography students in an…

School Segregation and Social Participation: The Case of Norwegian Children with Physical Disabilities

ERIC Educational Resources Information Center

Finnvold, Jon Erik

2018-01-01

This study explores the conditions that limit social participation for children with physical disabilities, and in particular, how school segregation practices affect participation in formal and informal after-school activities. In a sample of 491 children, to varying degrees, a majority of the children were taken out of ordinary classroom…

Exploring DNA variant segregation types in pooled genome sequencing enables effective mapping of weeping trait in Malus

USDA-ARS?s Scientific Manuscript database

In recent years, next generation sequencing (NGS) based bulked segregant analysis (BSA) has become a powerful approach for allele discovery in non-model plant species. However, challenges remain, particular for out-crossing species with complex genomes. Here, the genetic control of a weeping bran...

First-Principles Study of Mo Segregation in MoNi(111): Effects of Chemisorbed Atomic Oxygen

PubMed Central

Yu, Yanlin; Xiao, Wei; Wang, Jianwei; Wang, Ligen

2015-01-01

Segregation at metal alloy surfaces is an important issue because many electrochemical and catalytic properties are directly correlated to the surface composition. We have performed density functional theory calculations for Mo segregation in MoNi(111) in the presence of chemisorbed atomic oxygen. In particular, the coverage dependence and possible adsorption-induced segregation phenomena are addressed by investigating segregation energies of the Mo atom in MoNi(111). The theoretical calculated results show that the Mo atom prefers to be embedded in the bulk for the clean MoNi(111), while it segregates to the top-most layer when the oxygen coverage is thicker than 1/9 monolayer (ML). Furthermore, we analyze the densities of states for the clean and oxygen-chemisorbed MoNi(111), and see a strong covalent bonding between Mo d-band states and O p-states. The present study provides valuable insight for exploring practical applications of Ni-based alloys as hydrogen evolution electrodes. PMID:28787811

An International Comparison of Equity in Education Systems

ERIC Educational Resources Information Center

Gorard, Stephen; Smith, Emma

2004-01-01

This paper uses pupil responses to the PISA study in 2000 for all EU countries. Using indicators of the pupil intakes to schools and their outcomes it computes segregation indices for 15 countries, and then tries to explain the resulting patterns in terms of the characteristics of national school systems. Segregation by sex in each country is…

26 CFR 1.801-8 - Contracts with reserves based on segregated asset accounts.

Code of Federal Regulations, 2010 CFR

2010-04-01

...). The company retained with respect to such reserves from gross investment income on Separate Account A... retained with respect to such reserves from gross investment income on Separate Account B a total of $5,720... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Contracts with reserves based on segregated...

The first international leprosy conference, Berlin, 1897: the politics of segregation.

PubMed

Pandya, S S

2004-01-01

The present paper examines the first attempts to internationalise the problem of leprosy, a subject hitherto overlooked by historians of imperialism and disease. The last decade of the nineteenth century saw many in the civilised countries of the imperialist West gripped by a paranoia about an invasion of leprosy via germ-laden immigrants and returning expatriates who had acquired the infection in leprosy endemic colonial possessions. Such alarmists clamoured for the adoption of vigorous leper segregation policies in such colonies. But the contagiousness of leprosy did not go unquestioned by other westerners. The convocation in Berlin of the first international meeting on leprosy revealed the interplay of differing and sometimes incompatible views about the containment of leprosy by segregation. The roles of officials from several countries, as well as the roles of five protagonists (Albert Ashmead, Jules Goldschmidt, Edvard Ehlers. Armauer Hansen, and Phineas Abraham) in the shaping of the Berlin Conference are here examined.

The first international leprosy conference, Berlin, 1897: the politics of segregation.

PubMed

Pandya, Shubhada S

2003-01-01

The present paper examines the first attempts to internationalize the problem of leprosy, a subject hitherto overlooked by historians of imperialism and disease. The last decade of the nineteenth century saw many in the 'civilized countries' of the imperialist West gripped by a paranoia about an invasion of leprosy via germ-laden immigrants and returning expatriates who had acquired the infection in leprosy-endemic colonial possessions. Such alarmists clamoured for the adoption of vigorous leper segregation policies in such colonies. But the contagiousness of leprosy did not go unquestioned by other westerners. The convocation in Berlin of the first international meeting on leprosy revealed the interplay of differing and sometimes incompatible views about the containment of leprosy by segregation. The roles of officials from several countries, as well as the roles of five protagonists (Albert Ashmead, Jules Goldschmidt, Edvard Ehlers, Armauer Hansen, and Phineas Abraham) in the shaping of the Berlin Conference are here examined.

Patriotism Abroad: Overseas Chinese Students' Encounters With Criticisms of China

ERIC Educational Resources Information Center

Hail, Henry Chiu

2015-01-01

Prior research on international education suggests that host country students' lack of interest in talking to international students is a major cause of international student segregation. Some Chinese international students, however, complain that although host students want to talk with them about China, they often exhibit misinformed, prejudiced…

Together, yet Still Not Equal? Sex Integration in Equestrian Sport

ERIC Educational Resources Information Center

Dashper, Katherine

2012-01-01

Sex segregation is a core organising principle of most modern sports and is a key element in the marginalisation and subordination of girls and women in sport and beyond. In this article I explore the only Olympic-level sport which is not organised around sex segregation--equestrian sport--in order to consider the implications of sex integration…

To Lift as We Climb: A Textbook Analysis of the Segregated School Experience

ERIC Educational Resources Information Center

Pellegrino, Anthony; Mann, Linda; Russell, William B., III

2013-01-01

In this paper we share findings of a textbook analysis in which we explored the treatment of segregated education in eight, widely-used secondary United States history and government textbooks. We positioned our findings within the historiography related to the African American school experience which challenges the notion that the lack of…

Finding Common Ground: Coordinating Housing and Education Policy to Promote Integration

ERIC Educational Resources Information Center

Tegeler, Philip, Ed.

2011-01-01

The powerful, reciprocal connection between school and housing segregation has long been recognized. The housing-school link was a key element in both the 1968 Kerner Commission Report and in the legislative history of the Fair Housing Act. The relation of school and housing segregation was also explored in a series of school desegregation cases…

Choosing Segregation or Integration? The Extent and Effects of Ethnic Segregation in Dutch Cities

ERIC Educational Resources Information Center

Karsten, Sjoerd; Felix, Charles; Ledoux, Guuske; Meijnen, Wim; Roeleveld, Jaap; Van Schooten, Erik

2006-01-01

Across Europe, urban education systems are struggling with the process of integration of immigrants in schools. The process of inclusion and exclusion in European cities shows many similarities with earlier experiences in U.S. cities. This article explores the most important aspects of this new urban phenomenon and its impact on urban school…

Metropolitan area racial residential segregation, neighborhood racial composition, and breast cancer mortality.

PubMed

Russell, Emily F; Kramer, Michael R; Cooper, Hannah L F; Gabram-Mendola, Sheryl; Senior-Crosby, Diana; Jacob Arriola, Kimberly R

2012-09-01

There are significant relationships between racial residential segregation (RRS) and a range of health outcomes, including cancer-related outcomes. This study explores the contribution of metropolitan area RRS, census tract racial composition and breast cancer and all-cause mortality among black and white breast cancer patients. This study has three units of analysis: women diagnosed with breast cancer (n = 22,088), census tracts where they lived at diagnosis (n = 1,373), and the metropolitan statistical area (MSA)/micropolitan statistical area (MiSA) where they lived at diagnosis (n = 37). Neighborhood racial composition was measured as the percent of black residents in the census tract. Metropolitan area RRS was measured using the Information Theory Index. Multilevel Cox proportional hazards models examined the association of metropolitan area RRS and census tract racial composition with breast cancer and all-cause mortality. Survival analysis explored and compared the risk of death in women exposed to environments where a higher and lower proportion of residents were black. Breast cancer mortality disparities were largest in racially mixed tracts located in high MSA/MiSA segregation areas (RR = 2.06, 95 % CI 1.70, 2.50). For black but not white women, as MSA/MiSA RRS increased, there was an increased risk for breast cancer mortality (HR = 2.20, 95 % CI 1.09, 4.45). For all-cause mortality, MSA/MiSA segregation was not a significant predictor, but increasing tract percent black was associated with increased risk for white but not black women (HR 1.29, 95 % CI 1.05, 1.58). Racial residential segregation may influence health for blacks and whites differently. Pathways through which RRS patterns impact health should be further explored.

Agents of Change: Mixed-Race Households and the Dynamics of Neighborhood Segregation in the United States

PubMed Central

Ellis, Mark; Holloway, Steven R.; Wright, Richard; Fowler, Christopher S.

2014-01-01

This article explores the effects of mixed-race household formation on trends in neighborhood-scale racial segregation. Census data show that these effects are nontrivial in relation to the magnitude of decadal changes in residential segregation. An agent-based model illustrates the potential long-run impacts of rising numbers of mixed-race households on measures of neighborhood-scale segregation. It reveals that high rates of mixed-race household formation will reduce residential segregation considerably. This occurs even when preferences for own-group neighbors are high enough to maintain racial separation in residential space in a Schelling-type model. We uncover a disturbing trend, however; levels of neighborhood-scale segregation of single-race households can remain persistently high even while a growing number of mixed-race households drives down the overall rate of residential segregation. Thus, the article’s main conclusion is that parsing neighborhood segregation levels by household type—single versus mixed race—is essential to interpret correctly trends in the spatial separation of racial groups, especially when the fraction of households that are mixed race is dynamic. More broadly, the article illustrates the importance of household-scale processes for urban outcomes and joins debates in geography about interscalar relationships. PMID:25082984

Integrated schools, segregated curriculum: effects of within-school segregation on adolescent health behaviors and educational aspirations.

PubMed

Walsemann, Katrina M; Bell, Bethany A

2010-09-01

We examined the extent to which within-school segregation, as measured by unevenness in the distribution of Black and White adolescents across levels of the English curriculum (advanced placement-international baccalaureate-honors, general, remedial, or no English), was associated with smoking, drinking, and educational aspirations, which previous studies found are related to school racial/ethnic composition. We analyzed data from wave 1 of the National Longitudinal Study of Adolescent Health, restricting our sample to non-Hispanic Blacks (n=2731) and Whites (n=4158) who from 1994 to 1995 attended high schools that enrolled Black and White students. White female students had higher predicted probabilities of smoking or drinking than did Black female students; the largest differences were in schools with high levels of within-school segregation. Black male students had higher predicted probabilities of high educational aspirations than did White male students in schools with low levels of within-school segregation; this association was attenuated for Black males attending schools with moderate or high levels of within-school segregation. Our results provide evidence that within-school segregation may influence both students' aspirations and their behaviors.

The Way We Learned: African American Students' Memories of Schooling in the Segregated South

ERIC Educational Resources Information Center

Coats, Linda T.

2010-01-01

The purpose of this study was to explore the learning experiences and teachers' behaviors valued by students who attended southern rural segregated schools during the 1940s-1960s, The qualitative data yielded four themes: (a) memories of caring teachers, (b) memories of teachers as professionally, (c) memories of teachers as participants of the…

Challenging School Segregation in the Twenty-First Century: How Districts Can Leverage Dual Language Education to Increase School and Classroom Diversity

ERIC Educational Resources Information Center

Kotok, Stephen; DeMatthews, David

2018-01-01

Nationally, schools are increasingly segregated by race and poverty as a result of demographic shifts and a changing legal and political landscape. Based on evidence that students benefit academically and socially from attending integrating settings, many school districts are exploring options for providing diverse learning experiences. We examine…

An Exploration of Teacher Attrition and Mobility in High Poverty Racially Segregated Schools

ERIC Educational Resources Information Center

Djonko-Moore, Cara M.

2016-01-01

The purpose of this study was to examine the mobility (movement to a new school) and attrition (quitting teaching) patterns of teachers in high poverty, racially segregated (HPRS) schools in the US. Using 2007-9 survey data from the National Center for Education Statistics, a multi-level multinomial logistic regression was performed to examine the…

Cultivating Racial Literacy in White, Segregated Settings: Emotions as Site of Ethical Engagement and Inquiry

ERIC Educational Resources Information Center

Winans, Amy E.

2010-01-01

Drawing on writing from a first-year composition class, this article explores how White students approach racial literacy in a segregated, rural college setting in the United States. I argue for the importance of understanding how emotions inform and propel students' responses to what I believe needs to be understood as the ethical challenge of…

A New Predictive Model of Centerline Segregation in Continuous Cast Steel Slabs by Using Multivariate Adaptive Regression Splines Approach

PubMed Central

García Nieto, Paulino José; González Suárez, Victor Manuel; Álvarez Antón, Juan Carlos; Mayo Bayón, Ricardo; Sirgo Blanco, José Ángel; Díaz Fernández, Ana María

2015-01-01

The aim of this study was to obtain a predictive model able to perform an early detection of central segregation severity in continuous cast steel slabs. Segregation in steel cast products is an internal defect that can be very harmful when slabs are rolled in heavy plate mills. In this research work, the central segregation was studied with success using the data mining methodology based on multivariate adaptive regression splines (MARS) technique. For this purpose, the most important physical-chemical parameters are considered. The results of the present study are two-fold. In the first place, the significance of each physical-chemical variable on the segregation is presented through the model. Second, a model for forecasting segregation is obtained. Regression with optimal hyperparameters was performed and coefficients of determination equal to 0.93 for continuity factor estimation and 0.95 for average width were obtained when the MARS technique was applied to the experimental dataset, respectively. The agreement between experimental data and the model confirmed the good performance of the latter.

Importance of sequence specific hydrophobicity in synthetic protein transduction domain mimics.

PubMed

Sgolastra, Federica; Minter, Lisa M; Osborne, Barbara A; Tew, Gregory N

2014-03-10

A new series of synthetic protein transduction domain mimics (PTDMs) was designed to analyze the importance of guanidine and phenyl group segregation along the backbone on their membrane interaction and cellular internalization abilities. ROMP was utilized to synthesize three polymers: nonsegregated homopolymers, intermediately segregated gradient copolymers, and strongly segregated block copolymers. In order to understand the role of functional group segregation on activity, it was important to design monomers that enabled these three different polymer topologies, or constitutional macromolecular isomers, to be prepared with identical chemical compositions. The structure-activity relationships were evaluated by both a biophysical assay, using dye-loaded vesicles, and by in vitro cellular uptake studies of fluorescently labeled chains. The results showed that functional group segregation impacts activity. In general, the nonsegregated homopolymer was the most active in both assays but also showed larger, ill-defined aggregates compared to either the gradient or block copolymers. It was also the most cytotoxic of the three isomers. As a result, the gradient copolymer with intermediate segregation optimizes activity and solubility with low cytotoxicity. This study gives new design guidelines for the development of PTDMs.

DNA asymmetry in stem cells - immortal or mortal?

PubMed

Yadlapalli, Swathi; Yamashita, Yukiko M

2013-09-15

The immortal strand hypothesis proposes that stem cells retain a template copy of genomic DNA (i.e. an 'immortal strand') to avoid replication-induced mutations. An alternative hypothesis suggests that certain cells segregate sister chromatids non-randomly to transmit distinct epigenetic information. However, this area of research has been highly controversial, with conflicting data even from the same cell types. Moreover, historically, the same term of 'non-random sister chromatid segregation' or 'biased sister chromatid segregation' has been used to indicate distinct biological processes, generating a confusion in the biological significance and potential mechanism of each phenomenon. Here, we discuss the models of non-random sister chromatid segregation, and we explore the strengths and limitations of the various techniques and experimental model systems used to study this question. We also describe our recent study on Drosophila male germline stem cells, where sister chromatids of X and Y chromosomes are segregated non-randomly during cell division. We aim to integrate the existing evidence to speculate on the underlying mechanisms and biological relevance of this long-standing observation on non-random sister chromatid segregation.

Wider-community Segregation and the Effect of Neighbourhood Ethnic Diversity on Social Capital: An Investigation into Intra-Neighbourhood Trust in Great Britain and London

PubMed Central

Laurence, James

2016-01-01

Extensive research has demonstrated that neighbourhood ethnic diversity is negatively associated with intra-neighbourhood social capital. This study explores the role of segregation and integration in this relationship. To do so it applies three-level hierarchical linear models to two sets of data from across Great Britain and within London, and examines how segregation across the wider-community in which a neighbourhood is nested impacts trust amongst neighbours. This study replicates the increasingly ubiquitous finding that neighbourhood diversity is negatively associated with neighbour-trust. However, we demonstrate that this relationship is highly dependent on the level of segregation across the wider-community in which a neighbourhood is nested. Increasing neighbourhood diversity only negatively impacts neighbour-trust when nested in more segregated wider-communities. Individuals living in diverse neighbourhoods nested within integrated wider-communities experience no trust-penalty. These findings show that segregation plays a critical role in the neighbourhood diversity/trust relationship, and that its absence from the literature biases our understanding of how ethnic diversity affects social cohesion. PMID:28989199

Wider-community Segregation and the Effect of Neighbourhood Ethnic Diversity on Social Capital: An Investigation into Intra-Neighbourhood Trust in Great Britain and London.

PubMed

Laurence, James

2017-10-01

Extensive research has demonstrated that neighbourhood ethnic diversity is negatively associated with intra-neighbourhood social capital. This study explores the role of segregation and integration in this relationship. To do so it applies three-level hierarchical linear models to two sets of data from across Great Britain and within London, and examines how segregation across the wider-community in which a neighbourhood is nested impacts trust amongst neighbours. This study replicates the increasingly ubiquitous finding that neighbourhood diversity is negatively associated with neighbour-trust. However, we demonstrate that this relationship is highly dependent on the level of segregation across the wider-community in which a neighbourhood is nested. Increasing neighbourhood diversity only negatively impacts neighbour-trust when nested in more segregated wider-communities. Individuals living in diverse neighbourhoods nested within integrated wider-communities experience no trust-penalty. These findings show that segregation plays a critical role in the neighbourhood diversity/trust relationship, and that its absence from the literature biases our understanding of how ethnic diversity affects social cohesion.

A Culture of (In)Equality?: A Cross-National Study of Gender Parity and Gender Segregation in National School Systems

ERIC Educational Resources Information Center

Wiseman, Alexander W.

2008-01-01

Recent international education reports have highlighted some of the progress (as well as remaining disparity) in gendered education enrollment rates. But, the problem of gender segregation is still a very real issue even in some nations where girls are enrolled at levels on par with boys. Separate classes, curricula, and in many countries separate…

Self-Segregation or Global Mixing?: Social Interactions and the International Student Experience

ERIC Educational Resources Information Center

Rose-Redwood, CindyAnn R.; Rose-Redwood, Reuben S.

2013-01-01

This qualitative study examines the social interaction patterns among international students at a large research university in the Mid-Atlantic region of the United States. Based on semistructured interviews with 60 international graduate students, the researchers provide a conceptual framework that identifies 4 primary types of social…

Gender & Racial Inequality at Work: The Sources & Consequences of Job Segregation. Cornell Studies in Industrial and Labor Relations Number 27.

ERIC Educational Resources Information Center

Tomaskovic-Devey, Donald

This book proposes that job-level segregation by sex and race is a fundamentally important source of black-white and male-female inequalities in employment. Drawing on the North Carolina Employment and Health Survey, the first general population survey that measures the gender and racial compositions of jobs, the book explores this thesis in the…

The Evolution of Occupational Segregation in the United States, 1940-2010: Gains and Losses of Gender-Race/Ethnicity Groups.

PubMed

del Río, Coral; Alonso-Villar, Olga

2015-06-01

The aim of this article is twofold: (1) to descriptively explore the evolution of occupational segregation of women and men of different racial/ethnic groups in the United States during 1940-2010, and (2) to assess the consequences of segregation for each group. For that purpose, in this article, we propose a simple index that measures the monetary loss or gain of a group derived from its overrepresentation in some occupations and underrepresentation in others. This index has a clear economic interpretation. It represents the per capita advantage (if the index is positive) or disadvantage (if the index is negative) of the group, derived from its segregation, as a proportion of the average wage of the economy. Our index is a helpful tool not only for academics but also for institutions concerned with inequalities among demographic groups because it makes it possible to rank them according to their segregational nature.

77 FR 70213 - Capital, Margin, and Segregation Requirements for Security-Based Swap Dealers and Major Security...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-23

...In accordance with the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 (``Dodd-Frank Act''), the Securities and Exchange Commission (``Commission''), pursuant to the Securities Exchange Act of 1934 (``Exchange Act''), is proposing capital and margin requirements for security-based swap dealers (``SBSDs'') and major security-based swap participants (``MSBSPs''), segregation requirements for SBSDs, and notification requirements with respect to segregation for SBSDs and MSBSPs. The Commission also is proposing to increase the minimum net capital requirements for broker-dealers permitted to use the alternative internal model-based method for computing net capital (``ANC broker-dealers'').

Preferences, constraints, and the process of sex segregation in college majors: A choice analysis.

PubMed

Ochsenfeld, Fabian

2016-03-01

The persistence of horizontal sex segregation in higher education continues to puzzle social scientists. To help resolve this puzzle, we analyze a sample of college entrants in Germany with a discrete choice design that allows for social learning from the experiences of others. We make at least two contributions to the state of research. First, we test whether essentialist gender stereotypes affect major selection mostly through internalization or rather as external constraints that high school graduates adapt their behavior to. Empirically, we find that internalized vocational interests better explain gendered major choices than conformance with friends' and parents' expectations does. Second, we scrutinize whether segregation results from women's anticipation of gendered family roles or from their anticipation of sex-based discrimination, but we find no evidence for either of these hypotheses. As in most previous studies, differences in mathematics achievement fail to explain gendered patterns of selection into college majors. Copyright © 2016 Elsevier Inc. All rights reserved.

Single Vesicle Analysis of Endocytic Fission on Microtubules In Vitro

PubMed Central

Wolkoff, Allan W.

2016-01-01

Following endocytosis, internalized molecules are found within intracellular vesicles and tubules that move along the cytoskeleton and undergo fission, as demonstrated here using primary cultured rat hepatocytes. Although the use of depolymerizing drugs has shown that the cytoskeleton is not required to segregate endocytic protein, many studies suggest that the cytoskeleton is involved in the segregation of protein in normal cells. To investigate whether cytoskeletal-based movement results in the segregation of protein, we tracked the contents of vesicles during in vitro microscopy assays. These studies showed that the addition of ATP causes fission of endocytic contents along microtubules, resulting in the segregation of proteins that are targeted for different cellular compartments. The plasma membrane proteins, sodium (Na+) taurocholate cotransporting polypeptide (ntcp) and transferrin receptor, segregated from asialoorosomucoid (ASOR), an endocytic ligand that is targeted for degradation. Epidermal growth factor receptor, which is degraded, and the asialoglycoprotein receptor, which remains partially bound to ASOR, segregated less efficiently from ASOR. Vesicles containing ntcp and transferrin receptor had reduced fission in the absence of ASOR, suggesting that fission is regulated to allow proteins to segregate. A single round of fission resulted in 6.5-fold purification of ntcp from ASOR, and 25% of the resulting vesicles were completely depleted of the endocytic ligand. PMID:18284582

Energetics of vacancy segregation to [100] symmetric tilt grain boundaries in bcc tungsten

PubMed Central

Chen, Nanjun; Niu, Liang-Liang; Zhang, Ying; Shu, Xiaolin; Zhou, Hong-Bo; Jin, Shuo; Ran, Guang; Lu, Guang-Hong; Gao, Fei

2016-01-01

The harsh irradiation environment poses serious threat to the structural integrity of leading candidate for plasma-facing materials, tungsten (W), in future nuclear fusion reactors. It is thus essential to understand the radiation-induced segregation of native defects and impurities to defect sinks, such as grain boundaries (GBs), by quantifying the segregation energetics. In this work, molecular statics simulations of a range of equilibrium and metastable [100] symmetric tilt GBs are carried out to explore the energetics of vacancy segregation. We show that the low-angle GBs have larger absorption length scales over their high-angle counterparts. Vacancy sites that are energetically unfavorable for segregation are found in all GBs. The magnitudes of minimum segregation energies for the equilibrium GBs vary from −2.61 eV to −0.76 eV depending on the GB character, while those for the metastable GB states tend to be much lower. The significance of vacancy delocalization in decreasing the vacancy segregation energies and facilitating GB migration has been discussed. Metrics such as GB energy and local stress are used to interpret the simulation results, and correlations between them have been established. This study contributes to the possible application of polycrystalline W under irradiation in advanced nuclear fusion reactors. PMID:27874047

The Reach and Limitation of the ADA and its Integration Mandate: Implications for the Successful Reentry of Individuals with Mental Disabilities in a Correctional Population.

PubMed

Dlugacz, Henry A; Droubi, Luna

2017-03-01

This article argues that the ADA and its integration mandate, informed by international standards, should extend to incarcerated individuals with mental disabilities who reenter society, as they are at highly elevated risk for unnecessary segregation in institutions such as homeless shelters or hospitals or through reincarceration. An understanding of the precise services needed to prevent these strongly related but distinct variants of institutionalization requires a robust and continuing research agenda. In discussing the breadth of the ADA, we explore its history, interpretations of its application in a variety of contexts with respect to vulnerable populations and integration, and enforcement. We also turn to international approaches to integration mandates as they apply to reentry. By interpreting the domestic and international principles that create the context for integration we hope to have provided a resource for future application of the ADA integration in the context of prisoner reentry. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Engaging Chinese International Undergraduate Students in the American University

ERIC Educational Resources Information Center

Ross, Heidi; Chen, Yajing

2015-01-01

Vincent Tinto's theory of academic and social integration provides a framework for investigating perceived problems associated with Chinese international students' engagement at a public research-intensive university in the U.S. Midwest ("Midwest" University). These "problems"--classroom silence, segregation and…

The Role of Contextual Socioeconomic Circumstances and Neighborhood Poverty Segregation on Mortality in 4 European Cities.

PubMed

Marinacci, Chiara; Demaria, Moreno; Melis, Giulia; Borrell, Carme; Corman, Diana; Dell'Olmo, Marc Marí; Rodriguez, Maica; Costa, Giuseppe

2017-10-01

Several studies have recognized the health disadvantage of residents in socioeconomically deprived neighborhoods, independent of the influence of individual socioeconomic conditions. The effect of neighborhood socioeconomic deprivation on general mortality has appeared heterogeneous among the cities analyzed: the underlying mechanisms have been less empirically explored, and explanations for this heterogeneous health effect remain unclear. The present study aimed to: (1) analyze the distribution of socioeconomically disadvantaged persons in neighborhoods of 4 European cities-Turin, Barcelona, Stockholm and Helsinki-trying to measure segregation of residents according to their socioeconomic conditions. Two measuring approaches were used, respectively, through dissimilarity index and clustering estimated from Bayesian models. (2) Analyze the distribution of mortality in the above mentioned cities, trying to disentangle the independent effects of both neighborhood socioeconomic deprivation and neighborhood segregation of residents according to their socioeconomic conditions, using multilevel models. A significantly higher risk of death was observed among residents in more deprived neighborhoods in all 4 cities considered, slightly heterogeneous across them. Poverty segregation appeared to be slightly associated with increasing mortality in Turin and, among females and only according to dissimilarity, in Barcelona. Few studies have explored the health effects of social clustering, and results could inform urban policy design with regard to social mix.

Human Artificial Chromosomes with Alpha Satellite-Based De Novo Centromeres Show Increased Frequency of Nondisjunction and Anaphase Lag

PubMed Central

Rudd, M. Katharine; Mays, Robert W.; Schwartz, Stuart; Willard, Huntington F.

2003-01-01

Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes. PMID:14560014

Human artificial chromosomes with alpha satellite-based de novo centromeres show increased frequency of nondisjunction and anaphase lag.

PubMed

Rudd, M Katharine; Mays, Robert W; Schwartz, Stuart; Willard, Huntington F

2003-11-01

Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes.

MRI Measurements and Granular Dynamics Simulation of Segregation of Granular Mixture

NASA Technical Reports Server (NTRS)

Nakagawa, M.; Moss, Jamie L.; Altobelli, Stephen A.

1999-01-01

A counter intuitive axial segregation phenomenon in a rotating horizontal cylinder has recently captured attention of many researchers in different disciplines. There is a growing consensus that the interplay between the particle dynamics and the evolution of the internal structure during the segregation process must be carefully investigated. Magnetic resonance imaging (MRI) has been used to non-invasively obtain much needed dynamic/static information such as velocity and concentration profiles, and it has proven to be capable of depicting the evolution of segregation processes. Segregation in a rotating cylinder involves two processes: the first is to transport small particles in the radial direction to form a radial core, and the second is to transform the radial core into axially segregated bands. Percolation and/or "stopping" have been proposed as mechanisms for the radial segregation. As to mechanisms for axial band formation, much less is known. The difference in the dynamic angle of repose has been proposed to segregate different components in the axial direction. Recently, Hill and Kakalios have reported that particles mix or demix depending upon the competition between diffusion and preferential drift whose order can be determined by the dynamic angle of repose through the adjustment of the rotation rate. We claim that the dynamic angle of repose could be one of the causes, however, it fails to offer reasonable explanations for certain aspects of the axial migration. For example, we always observe that the radial segregation precedes the axial segregation and small particles migrate in the radial direction to form an axially extended radial core. It then transforms into axially segregated bands. By definition, the effects of the dynamic angle of repose are restricted near the free surface where the flowing layer is present. However, during the process of transforming from the radially segregated core to axially segregated bands, small particles located in the deep core region, which is untouched by the flowing layer, also completely disappear. Usually, the dynamics angle of repose are uniquely defined for individual species to characterize particle properties, and the dynamic angle of repose thus defined provides little information for the dynamic angle of repose of the mixture since the concentration ratio and the internal packing structure do not remain the same during the segregation processes. Under microgravity environment, the dynamics angle of repose argument does not hold since there is simply no flowing layer to influence/determine the preferred directions of segregation. We have thus designed an experiment so that the effects of the dynamic angle of repose can be minimized by filling the cylinder almost completely full. Small particles still formed a radial core and also migrated to form axial bands. As ground based experiments we have designed and conducted both 2D and 3D segregation experiments. The 2D experiments are performed using a thin cylinder (the gap between two end caps is about 5 mm) filled with different combinations of particles. The 3D experiments are conducted with a long cylinder of its length and diameter of 27cm and 7cm, respectively. Results of 2D experiments indicate that different mechanisms govern particle motion in regions near and far from the axis of rotation. Results of 3D experiments indicate that a series of collapses of microstructures of particle packing (micro-collapses) may be responsible for the creation of voids for small particles to migrate through in the axial direction. We have successfully eliminated the dynamic angle of repose as a cause for segregation, however, by almost completely filling the cylinder with the particles, we have lost an opportunity to investigate a possibility of particle "mobility" being a cause for segregation which requires a flowing surface but not the difference in the angle of repose. This is currently being investigated.

Improving waste segregation while reducing costs in a tertiary-care hospital in a lower-middle-income country in Central America.

PubMed

Johnson, Kyle M; González, Miriam L; Dueñas, Lourdes; Gamero, Mario; Relyea, George; Luque, Laura E; Caniza, Miguela A

2013-07-01

Healthcare waste (HCW) management and segregation are essential to ensure safety, environmental protection and cost control. Poor HCW management increase risks and costs for healthcare institutions. On-going surveillance and training are important to maintain good HCW practices. Our objectives were to evaluate and improve HCW practices at Hospital Bloom, San Salvador, El Salvador. We studied HCW disposal practices by observing waste containers, re-segregating waste placed in biohazardous waste bags, and administering a seven-itemsknowledge survey before and after training in waste management at Hospital Bloom. The training was based on national and international standards. We followed total biohazardous waste production before and after the training. The hospital staff was knowledgeable about waste segregation practices, but had poor compliance with national policies. Re-segregating waste in biohazardous waste bags showed that 61% of this waste was common waste, suggesting that the staff was possibly unaware of the cost of mis-segregating healthcare waste. After staff training in HCW management, the correct responses increased by 44% and biohazardous waste disposal at the hospital reduced by 48%. Better segregation of biohazardous waste and important savings can be obtained by HCW management education of hospital staff. Hospitals can benefit from maximising the use of available resources by sustaining best practices of HCW, especially those in hospitals in lower-middle-income countries.

Thermal Coefficient of Linear Expansion Modified by Dendritic Segregation in Nickel-Iron Alloys

NASA Astrophysics Data System (ADS)

Ogorodnikova, O. M.; Maksimova, E. V.

2018-05-01

The paper presents investigations of thermal properties of Fe-Ni and Fe-Ni-Co casting alloys affected by the heterogeneous distribution of their chemical elements. It is shown that nickel dendritic segregation has a negative effect on properties of studied invars. A mathematical model is proposed to explore the influence of nickel dendritic segregation on the thermal coefficient of linear expansion (TCLE) of the alloy. A computer simulation of TCLE of Fe-Ni-Co superinvars is performed with regard to a heterogeneous distribution of their chemical elements over the whole volume. The ProLigSol computer software application is developed for processing the data array and results of computer simulation.

The endocytic recycling compartment maintains cargo segregation acquired upon exit from the sorting endosome

PubMed Central

Xie, Shuwei; Bahl, Kriti; Reinecke, James B.; Hammond, Gerald R. V.; Naslavsky, Naava; Caplan, Steve

2016-01-01

The endocytic recycling compartment (ERC) is a series of perinuclear tubular and vesicular membranes that regulates recycling to the plasma membrane. Despite evidence that cargo is sorted at the early/sorting endosome (SE), whether cargo mixes downstream at the ERC or remains segregated is an unanswered question. Here we use three-dimensional (3D) structured illumination microscopy and dual-channel and 3D direct stochastic optical reconstruction microscopy (dSTORM) to obtain new information about ERC morphology and cargo segregation. We show that cargo internalized either via clathrin-mediated endocytosis (CME) or independently of clathrin (CIE) remains segregated in the ERC, likely on distinct carriers. This suggests that no further sorting occurs upon cargo exit from SE. Moreover, 3D dSTORM data support a model in which some but not all ERC vesicles are tethered by contiguous “membrane bridges.” Furthermore, tubular recycling endosomes preferentially traffic CIE cargo and may originate from SE membranes. These findings support a significantly altered model for endocytic recycling in mammalian cells in which sorting occurs in peripheral endosomes and segregation is maintained at the ERC. PMID:26510502

Colonic stem cell data are consistent with the immortal model of stem cell division under non-random strand segregation.

PubMed

Walters, K

2009-06-01

Colonic stem cells are thought to reside towards the base of crypts of the colon, but their numbers and proliferation mechanisms are not well characterized. A defining property of stem cells is that they are able to divide asymmetrically, but it is not known whether they always divide asymmetrically (immortal model) or whether there are occasional symmetrical divisions (stochastic model). By measuring diversity of methylation patterns in colon crypt samples, a recent study found evidence in favour of the stochastic model, assuming random segregation of stem cell DNA strands during cell division. Here, the effect of preferential segregation of the template strand is considered to be consistent with the 'immortal strand hypothesis', and explore the effect on conclusions of previously published results. For a sample of crypts, it is shown how, under the immortal model, to calculate mean and variance of the number of unique methylation patterns allowing for non-random strand segregation and compare them with those observed. The calculated mean and variance are consistent with an immortal model that incorporates non-random strand segregation for a range of stem cell numbers and levels of preferential strand segregation. Allowing for preferential strand segregation considerably alters previously published conclusions relating to stem cell numbers and turnover mechanisms. Evidence in favour of the stochastic model may not be as strong as previously thought.

Opposing dorsal/ventral stream dynamics during figure-ground segregation.

PubMed

Wokke, Martijn E; Scholte, H Steven; Lamme, Victor A F

2014-02-01

The visual system has been commonly subdivided into two segregated visual processing streams: The dorsal pathway processes mainly spatial information, and the ventral pathway specializes in object perception. Recent findings, however, indicate that different forms of interaction (cross-talk) exist between the dorsal and the ventral stream. Here, we used TMS and concurrent EEG recordings to explore these interactions between the dorsal and ventral stream during figure-ground segregation. In two separate experiments, we used repetitive TMS and single-pulse TMS to disrupt processing in the dorsal (V5/HMT⁺) and the ventral (lateral occipital area) stream during a motion-defined figure discrimination task. We presented stimuli that made it possible to differentiate between relatively low-level (figure boundary detection) from higher-level (surface segregation) processing steps during figure-ground segregation. Results show that disruption of V5/HMT⁺ impaired performance related to surface segregation; this effect was mainly found when V5/HMT⁺ was perturbed in an early time window (100 msec) after stimulus presentation. Surprisingly, disruption of the lateral occipital area resulted in increased performance scores and enhanced neural correlates of surface segregation. This facilitatory effect was also mainly found in an early time window (100 msec) after stimulus presentation. These results suggest a "push-pull" interaction in which dorsal and ventral extrastriate areas are being recruited or inhibited depending on stimulus category and task demands.

26 CFR 1.468B-0 - Table of contents.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED... services. (2) CERCLA liabilities. (g) Excluded liabilities. (h) Segregation requirement. (1) In general. (2... settlement fund. (f) Distribution of property. (g) Other taxes. (h) Denial of credits against tax. (i...

Neighborhood Foreclosures, Racial/Ethnic Transitions, and Residential Segregation

PubMed Central

Hall, Matthew; Crowder, Kyle; Spring, Amy

2015-01-01

In this article, we use data on virtually all foreclosure events between 2005 and 2009 to calculate neighborhood foreclosure rates for nearly all block groups in the United States to assess the impact of housing foreclosures on neighborhood racial/ethnic change and on broader patterns of racial residential segregation. We find that the foreclosure crisis was patterned strongly along racial lines: black, Latino, and racially integrated neighborhoods had exceptionally high foreclosure rates. Multilevel models of racial/ethnic change reveal that foreclosure concentrations were linked to declining shares of whites and expanding shares of black and Latino residents. Results further suggest that these compositional shifts were driven by both white population loss and minority growth, especially from racially mixed settings with high foreclosure rates. To explore the impact of these racially selective migration streams on patterns of residential segregation, we simulate racial segregation assuming that foreclosure rates remained at their 2005 levels throughout the crisis period. Our simulations suggest that the foreclosure crisis increased racial segregation between blacks and whites by 1.1 dissimilarity points, and between Latinos and whites by 2.2 dissimilarity points. PMID:26120142

Te-and Zn-Doped InSb Crystals Grown in Microgravity

NASA Technical Reports Server (NTRS)

Ostrogorsky, A. G.; Marin, C.; Volz, M.; Bonner, W. A.; Duffar, T.

2004-01-01

In 2002, within the SUBSA (Solidification Using a Baffle in Sealed Ampoules) investigation, seven doped InSb crystals were grown in microgravity at the International Space Station. The key goals of the SUBSA investigation are: (a) to clarify the origin of the melt convection in space laboratories; (b) to reduce melt convection to the level which allows reproducible diffusion-controlled segregation; (e) to explore the submerged baffle process and liquid encapsulation in microgravity. 30 crystal growth experiments were conducted in the ground unit, to optimize the design of flight ampoules and to test the transparent SUBSA furnace developed by TecMasters Inc. The specially designed furnace, allowed observation of the crystal growth process (melting, seeding, motion of the solid-liquid interface, etc.). In the summer of 2002, eight crystal growth experiments were conducted in the Microgravity Science Glovebox (MSG) facility at the ISS. Four Te-doped (k = 0.5) and three Zn-doped (k2.9) crystals were grown on undoped seeds. In one experiment, we were not able to seed and grow. The seven grown crystals were sectioned and analyzed using SIMS. The design of the SUBSA ampoules, the segregation data and the video images obtained during the SUBSA flight experiments will be presented and discussed.

Segregation and trapping of oxygen vacancies near the SrTiO 3Σ3 (112) [110] tilt grain boundary

DOE PAGES

Liu, Bin; Cooper, Valentino R.; Zhang, Yanwen; ...

2015-03-21

In nanocrystalline materials, structural discontinuities at grain boundaries (GBs) and the segregation of point defects to these GBs play a key role in defining the structural stability of a material, as well as its macroscopic electrical/mechanical properties. In this study, the segregation of oxygen vacancies near the Σ3 (1 1 2) [¯110] tilt GB in SrTiO 3 is explored using density functional theory. We find that oxygen vacancies segregate toward the GB, preferring to reside within the next nearest-neighbor layer. This oxygen vacancy segregation is found to be crucial for stabilizing this tilt GB. Furthermore, we find that the migrationmore » barriers of oxygen vacancies diffusing toward the first nearest-neighbor layer of the GB are low, while those away from this layer are very high. Furthermore, the segregation and trapping of the oxygen vacancies in the first nearest-neighbor layer of GBs are attributed to the large local distortions, which can now accommodate the preferred sixfold coordination of Ti. These results suggest that the electronic, transport, and capacitive properties of SrTiO 3 can be engineered through the control of GB structure and grain size or layer thickness.« less

Residential Ethnic Segregation and Stroke Risk in Mexican Americans: The Brain Attack Surveillance in Corpus Christi Project

PubMed Central

Patel, Rajiv C; Baek, Jonggyu; Smith, Melinda A; Morgenstern, Lewis B; Lisabeth, Lynda D

2015-01-01

Objective Residential ethnic segregation may operate through multiple mechanisms to increase stroke risk. The current study evaluated if residential ethnic segregation was associated with stroke risk in a bi-ethnic population. Design Incident strokes were identified in Nueces County, Texas from 2000 to 2010. Residential ethnic segregation (range: 0–1) was derived for each census tract in the county (n=64) using 2000 U.S Census data, and categorized into: predominantly non-Hispanic white (NHW, <0.3); ethnically mixed (0.3–0.7); predominantly Mexican American (MA, >0.7). Multilevel Poisson regression models were fitted separately for NHWs and MAs to assess the association between residential ethnic segregation (predominantly NHW referent) and relative risk for stroke, adjusted for age category, sex and census tract-level median per capita income. Effect modification by age was also examined. Results In adjusted models, residential ethnic segregation was not associated with stroke risk in either ethnic group. Effect modification by age was significant in both groups. Young MAs and NHWs living in predominantly MA census tracts were at greater relative risk for stroke than those living in predominantly NHW census tracts, but this association was only significant for MAs [MAs: RR = 2.38 (95% CI: 1.31–4.31); NHWs: RR = 1.53 (95% CI: 0.92–2.52)]. Conclusion Our findings demonstrate that residential ethnic segregation may influence downstream stroke risk in young MAs. Pathways between residential ethnic segregation and stroke in young MAs should be explored. PMID:25812246

Sex- and Gamete-Specific Patterns of X Chromosome Segregation in a Trioecious Nematode.

PubMed

Tandonnet, Sophie; Farrell, Maureen C; Koutsovoulos, Georgios D; Blaxter, Mark L; Parihar, Manish; Sadler, Penny L; Shakes, Diane C; Pires-daSilva, Andre

2018-01-08

Three key steps in meiosis allow diploid organisms to produce haploid gametes: (1) homologous chromosomes (homologs) pair and undergo crossovers; (2) homologs segregate to opposite poles; and (3) sister chromatids segregate to opposite poles. The XX/XO sex determination system found in many nematodes [1] facilitates the study of meiosis because variation is easily recognized [2-4]. Here we show that meiotic segregation of X chromosomes in the trioecious nematode Auanema rhodensis [5] varies according to sex (hermaphrodite, female, or male) and type of gametogenesis (oogenesis or spermatogenesis). In this species, XO males exclusively produce X-bearing sperm [6, 7]. The unpaired X precociously separates into sister chromatids, which co-segregate with the autosome set to generate a functional haplo-X sperm. The other set of autosomes is discarded into a residual body. Here we explore the X chromosome behavior in female and hermaphrodite meioses. Whereas X chromosomes segregate following the canonical pattern during XX female oogenesis to yield haplo-X oocytes, during XX hermaphrodite oogenesis they segregate to the first polar body to yield nullo-X oocytes. Thus, crosses between XX hermaphrodites and males yield exclusively male progeny. During hermaphrodite spermatogenesis, the sister chromatids of the X chromosomes separate during meiosis I, and homologous X chromatids segregate to the functional sperm to create diplo-X sperm. Given these intra-species, intra-individual, and intra-gametogenesis variations in the meiotic program, A. rhodensis is an ideal model for studying the plasticity of meiosis and how it can be modulated. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

International Policy and Roma Education in Europe: Essential Inputs or Centralized Distractions?

ERIC Educational Resources Information Center

Ram, Melanie H.

2015-01-01

This article examines the case of Roma inclusion in education as a study of the ways in which international policy can and cannot bring change at the local level. I first reflect on the numerous international organizations and initiatives to improve the educational outcomes of Roma, and to reduce segregation and other non-inclusionary practices.…

Women's representation in 60 occupations from 1972 to 2010: more women in high-status jobs, few women in things-oriented jobs.

PubMed

Lippa, Richard A; Preston, Kathleen; Penner, John

2014-01-01

To explore factors associated with occupational sex segregation in the United States over the past four decades, we analyzed U.S. Bureau of Labor Statistics data for the percent of women employed in 60 varied occupations from 1972 to 2010. Occupations were assessed on status, people-things orientation, and data-ideas orientation. Multilevel linear modeling (MLM) analyses showed that women increasingly entered high-status occupations from 1972 to 2010, but women's participation in things-oriented occupations (e.g., STEM fields and mechanical and construction trades) remained low and relatively stable. Occupations' data-ideas orientation was not consistently related to sex segregation. Because of women's increased participation in high-status occupations, occupational status became an increasingly weak predictor of women's participation rates in occupations, whereas occupations' people-things orientation became an increasingly strong predictor over time. These findings are discussed in relation to theories of occupational sex segregation and social policies to reduce occupational sex segregation.

Women's Representation in 60 Occupations from 1972 to 2010: More Women in High-Status Jobs, Few Women in Things-Oriented Jobs

PubMed Central

Lippa, Richard A.; Preston, Kathleen; Penner, John

2014-01-01

To explore factors associated with occupational sex segregation in the United States over the past four decades, we analyzed U.S. Bureau of Labor Statistics data for the percent of women employed in 60 varied occupations from 1972 to 2010. Occupations were assessed on status, people-things orientation, and data-ideas orientation. Multilevel linear modeling (MLM) analyses showed that women increasingly entered high-status occupations from 1972 to 2010, but women's participation in things-oriented occupations (e.g., STEM fields and mechanical and construction trades) remained low and relatively stable. Occupations' data-ideas orientation was not consistently related to sex segregation. Because of women's increased participation in high-status occupations, occupational status became an increasingly weak predictor of women's participation rates in occupations, whereas occupations' people-things orientation became an increasingly strong predictor over time. These findings are discussed in relation to theories of occupational sex segregation and social policies to reduce occupational sex segregation. PMID:24788710

Heroin Mismatch in the Motor City: Addiction, Segregation and the Geography of Opportunity

PubMed Central

Draus, Paul; Roddy, Juliette; Greenwald, Mark

2012-01-01

In this paper, we employ data drawn from economic and ethnographic interviews with Detroit heroin users, as well as other sources, to illustrate the relationship between heroin users’ mobility patterns and urban and suburban environments, especially in terms of drug acquisition and the geography of opportunity. We explore how the “spatial mismatch” (Kain 1968; 1992) between legal work opportunities and central city residents is seemingly reversed in the case of heroin users. We find that while both geographic location and social networks associated with segregation provide central city residents and African Americans with a strategic advantage over white suburbanites in locating and purchasing heroin easily and efficiently, this same segregation effectively focuses the negative externalities of heroin markets in central city neighborhoods. Finally, we consider how the heroin trade reflects and reproduces the segregated post-industrial landscape, and we discuss directions for potential future research on the relationship between ethnic and economic ghettos and regional drug markets. PMID:22679895

Familial Aggregation and Segregation Analysis in Families Presenting Autoimmunity, Polyautoimmunity, and Multiple Autoimmune Syndrome

PubMed Central

Castiblanco, John; Sarmiento-Monroy, Juan Camilo; Mantilla, Ruben Dario; Rojas-Villarraga, Adriana; Anaya, Juan-Manuel

2015-01-01

Studies documenting increased risk of developing autoimmune diseases (ADs) have shown that these conditions share several immunogenetic mechanisms (i.e., the autoimmune tautology). This report explored familial aggregation and segregation of AD, polyautoimmunity, and multiple autoimmune syndrome (MAS) in 210 families. Familial aggregation was examined for first-degree relatives. Segregation analysis was implemented as in S.A.G.E. release 6.3. Data showed differences between late- and early-onset families regarding their age, age of onset, and sex. Familial aggregation of AD in late- and early-onset families was observed. For polyautoimmunity as a trait, only aggregation was observed between sibling pairs in late-onset families. No aggregation was observed for MAS. Segregation analyses for AD suggested major gene(s) with no clear discernible classical known Mendelian transmission in late-onset families, while for polyautoimmunity and MAS no model was implied. Data suggest that polyautoimmunity and MAS are not independent traits and that gender, age, and age of onset are interrelated factors influencing autoimmunity. PMID:26697508

Molecular Mobility in Phase Segregated Bottlebrush Block Copolymer Melts

NASA Astrophysics Data System (ADS)

Yavitt, Benjamin; Gai, Yue; Song, Dongpo; Winter, H. Henning; Watkins, James

We investigate the linear viscoelastic behavior of poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) brush block copolymer (BBCP) materials over a range of vol. fractions and with side chain lengths below the entanglement molecular weights. The high chain mobility of the brush architecture results in rapid micro-phase segregation of the brush copolymer segments, which occurs during thermal annealing at mild temperatures. Master curves of the dynamic moduli were obtained by time-temperature superposition. The reduced degree of chain entanglements leads to a unique liquid-like rheology similar to that of bottlebrush homopolymers, even in the phase segregated state. We also explore the alignment of phase segregated domains at exceptionally low strain amplitudes (γ = 0.01) and mild processing temperatures using small angle X-ray scattering (SAXS). Domain orientation occurred readily at strains within the linear viscoelastic regime without noticeable effect on the moduli. This interplay of high molecular mobility and rapid phase segregation that are exhibited simultaneously in BBCPs is in contrast to the behavior of conventional linear block copolymer (LBCP) analogs and opens up new possibilities for processing BBCP materials for a wide range of nanotechnology applications. NSF Center for Hierarchical Manufacturing at the University of Massachusetts, Amherst (CMMI-1025020).

Enclaves of opportunity or "ghettos of last resort?" Assessing the effects of immigrant segregation on violent crime rates.

PubMed

Feldmeyer, Ben; Harris, Casey T; Scroggins, Jennifer

2015-07-01

A growing body of research indicates that immigration to the U.S. has crime-reducing effects on aggregate levels of violence, which researchers have often attributed to the protective and revitalizing effects of immigrants settling in spatially concentrated neighborhoods. However, recent scholarship suggests that growing shares of the foreign-born population are bypassing these segregated immigrant enclaves and are dispersing more widely to other urban neighborhoods. Moreover, some scholars suggest that spatially isolating immigrant populations may not always be protective, but could actually contribute to social problems like crime, particularly in disadvantaged contexts. The current study offers one of the first analyses exploring the way that segregation of immigrant populations (relative to the U.S.-born) is related to year 2000 violent crime rates for nearly 500 census places in California and New York. Results of our analysis reveal no direct link between immigrant segregation and macro-level violence, but instead show that these effects are highly contextualized and depend on the resources present in locales. Specifically, immigrant segregation contributes to violence in highly disadvantaged places but is linked to lower violence in areas with greater resources. Copyright © 2015 Elsevier Inc. All rights reserved.

Management of plastic wastes at Brazilian ports and diagnosis of their generation.

PubMed

Neffa Gobbi, Clarice; Lourenço Sanches, Vânia Maria; Acordi Vasques Pacheco, Elen Beatriz; de Oliveira Cavalcanti Guimarães, Maria José; Vasconcelos de Freitas, Marcos Aurélio

2017-11-15

This study evaluated the management of plastic wastes at 20 Brazilian maritime ports, from three sources: vessels, leased and non-leased areas. The data were obtained from documents on port wastes organized in a relational database with defined protocols (closed form). Analysis of the spreadsheets prepared and field visits revealed that the main bottleneck in managing plastic wastes at ports is their segregation. In general, more material is segregated and sent for recycling from leased areas than non-leased ones (administered by the government). This relatively better performance in managing the wastes generated in leased areas is probably due to the need for private operators to comply with the international standards such as the Code of Environmental Practice to satisfy the international market. Copyright © 2017 Elsevier Ltd. All rights reserved.

Understanding principles of integration and segregation using whole-brain computational connectomics: implications for neuropsychiatric disorders

PubMed Central

Lord, Louis-David; Stevner, Angus B.; Kringelbach, Morten L.

2017-01-01

To survive in an ever-changing environment, the brain must seamlessly integrate a rich stream of incoming information into coherent internal representations that can then be used to efficiently plan for action. The brain must, however, balance its ability to integrate information from various sources with a complementary capacity to segregate information into modules which perform specialized computations in local circuits. Importantly, evidence suggests that imbalances in the brain's ability to bind together and/or segregate information over both space and time is a common feature of several neuropsychiatric disorders. Most studies have, however, until recently strictly attempted to characterize the principles of integration and segregation in static (i.e. time-invariant) representations of human brain networks, hence disregarding the complex spatio-temporal nature of these processes. In the present Review, we describe how the emerging discipline of whole-brain computational connectomics may be used to study the causal mechanisms of the integration and segregation of information on behaviourally relevant timescales. We emphasize how novel methods from network science and whole-brain computational modelling can expand beyond traditional neuroimaging paradigms and help to uncover the neurobiological determinants of the abnormal integration and segregation of information in neuropsychiatric disorders. This article is part of the themed issue ‘Mathematical methods in medicine: neuroscience, cardiology and pathology’. PMID:28507228

Indulging our gendered selves? Sex segregation by field of study in 44 countries.

PubMed

Charles, Maria; Bradley, Karen

2009-01-01

Data from 44 societies are used to explore sex segregation by field of study. Contrary to accounts linking socioeconomic modernization to a "degendering" of public-sphere institutions, sex typing of curricular fields is stronger in more economically developed contexts. The authors argue that two cultural forces combine in advanced industrial societies to create a new sort of sex segregation regime. The first is gender-essentialist ideology, which has proven to be extremely resilient even in the most liberal-egalitarian of contexts; the second is self-expressive value systems, which create opportunities and incentives for the expression of "gendered selves." Multivariate analyses suggest that structural features of postindustrial labor markets and modern educational systems support the cultivation, realization, and display of gender-specific curricular affinities.

Flexibility of centromere and kinetochore structures

PubMed Central

Burrack, Laura S.; Berman, Judith

2012-01-01

Centromeres, and the kinetochores that assemble on them, are essential for accurate chromosome segregation. Diverse centromere organization patterns and kinetochore structures have evolved in eukaryotes ranging from yeast to humans. In addition, centromere DNA and kinetochore position can vary even within individual cells. This flexibility manifests in several ways: centromere DNA sequences evolve rapidly, kinetochore positions shift in response to altered chromosome structure, and kinetochore complex numbers change in response to fluctuations in kinetochore protein levels. Despite their differences, all of these diverse structures promote efficient chromosome segregation. This robustness is inherent to chromosome segregation mechanisms and balances genome stability with adaptability. In this review, we explore the mechanisms and consequences of centromere and kinetochore flexibility as well as the benefits and limitations of different experimental model systems for studying them. PMID:22445183

Exploring Attitude Transformation: A Grounded Theory Study of Romanian Teachers of Roma Students

ERIC Educational Resources Information Center

Jones, Laura Estella

2016-01-01

The purpose of this systematic grounded theory study was to explore the process of change in teacher attitudes toward including Roma ("Gypsy") students in non-segregated schools in Romania. The theories guiding this study included Mezirow's (1991, 2000) theory of transformation, Gay's (2002, 2013) theory of culturally responsive…

Chemical segregation in metallic glass nanowires.

PubMed

Zhang, Qi; Li, Qi-Kai; Li, Mo

2014-11-21

Nanowires made of metallic glass have been actively pursued recently due to the superb and unique properties over those of the crystalline materials. The amorphous nanowires are synthesized either at high temperature or via mechanical disruption using focused ion beam. These processes have potential to cause significant changes in structure and chemical concentration, as well as formation of defect or imperfection, but little is known to date about the possibilities and mechanisms. Here, we report chemical segregation to surfaces and its mechanisms in metallic glass nanowires made of binary Cu and Zr elements from molecular dynamics simulation. Strong concentration deviation are found in the nanowires under the conditions similar to these in experiment via focused ion beam processing, hot imprinting, and casting by rapid cooling from liquid state. Our analysis indicates that non-uniform internal stress distribution is a major cause for the chemical segregation, especially at low temperatures. Extension is discussed for this observation to multicomponent metallic glass nanowires as well as the potential applications and side effects of the composition modulation. The finding also points to the possibility of the mechanical-chemical process that may occur in different settings such as fracture, cavitation, and foams where strong internal stress is present in small length scales.

Measures Matter: The Local Exposure/Isolation (LEx/Is) Metrics and Relationships Between Local Level Segregation and Breast Cancer Survival

PubMed Central

Bemanian, Amin; Beyer, Kirsten M.M.

2017-01-01

Background The Black to White disparity in breast cancer survival is increasing, and racial residential segregation is a potential driver for this trend. However, study findings have been mixed, and no study has comprehensively compared the effectiveness of different local level segregation metrics in explaining cancer survival. Methods We proposed a set of new local segregation metrics named LEx/Is (Local Exposure and Isolation) and compared our new local isolation metric to two related metrics - the location quotient (LQ) and the index of concentration at extremes (ICE) - across the 102 largest US metropolitan areas. Then, using case data from the Milwaukee, WI metropolitan area, we used proportional hazards models to explore associations between segregation and breast cancer survival. Results Across the 102 metropolitan areas, the new local isolation metric was less skewed than the LQ or ICE. Across all races, Hispanic isolation was associated with poorer all-cause survival, and Hispanic LQ and Hispanic-White ICE were found to be associated with poorer survival for both breast cancer specific and all-cause mortality. For Black patients, Black LQ was associated with lower all-cause mortality and Black local isolation was associated with reduced all-cause and breast cancer specific mortality. ICE was found to suffer from high multicollinearity. Conclusions Local segregation is associated with breast cancer survival, but associations varied based on patient race and metric employed. Impact We highlight how selection of a segregation measure can alter study findings. These relationships need to be validated in other geographic areas. PMID:28325737

Heterogeneous Two-Phase Pillars in Epitaxial NiFe 2 O 4 -LaFeO 3 Nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Comes, Ryan B.; Perea, Daniel E.; Spurgeon, Steven R.

2017-07-10

Self-assembled epitaxial oxide nanocomposites have been explored for a wide range of applications, including multiferroic and magnetoelectric properties, plasmonics, and catalysis. These so-called “vertically aligned nanocomposites” form spontaneously during the deposition process when segregation into two phases is energetically favorable as compared to a solid solution. However, there has been surprisingly little work understanding the driving forces that govern the synthesis of these materials, which can include point defect energetics, surface diffusion, and interfacial energies. To explore these factors, La-Ni-Fe-O films have been synthesized by molecular beam epitaxy and it is shown that these phase segregate into spinel-perovskite nanocomposites. Usingmore » complementary scanning transmission electron microscopy and atom-probe tomography, the elemental composition of each phase is examined and found that Ni ions are exclusively found in the spinel phase. From correlative analysis, a model for the relative favorability of the Ni2+ and Ni3+ valences under the growth conditions is developed. It is shown that multidimensional characterization techniques provide previously unobserved insight into the growth process and complex driving forces for phase segregation.« less

Mineral Plot from Esperance Target

NASA Image and Video Library

2014-01-23

This plot segregates various minerals examined by NASA Mars Exploration Rover Opportunity according to their different compositions; for example, those with more iron and magnesium oxides are located in the lower right corner.

Role of Internal Variability in Surface Temperature and Precipitation Change Uncertainties over India.

NASA Astrophysics Data System (ADS)

Achutarao, K. M.; Singh, R.

2017-12-01

There are various sources of uncertainty in model projections of future climate change. These include differences in the formulation of climate models, internal variability, and differences in scenarios. Internal variability in a climate system represents the unforced change due to the chaotic nature of the climate system and is considered irreducible (Deser et al., 2012). Internal variability becomes important at regional scales where it can dominate forced changes. Therefore it needs to be carefully assessed in future projections. In this study we segregate the role of internal variability in the future temperature and precipitation projections over the Indian region. We make use of the Coupled Model Inter-comparison Project - phase 5 (CMIP5; Taylor et al., 2012) database containing climate model simulations carried out by various modeling centers around the world. While the CMIP5 experimental protocol recommended producing numerous ensemble members, only a handful of the modeling groups provided multiple realizations. Having a small number of realizations is a limitation in producing a quantification of internal variability. We therefore exploit the Community Earth System Model Large Ensemble (CESM-LE; Kay et al., 2014) dataset which contains a 40 member ensemble of a single model- CESM1 (CAM5) to explore the role of internal variability in Future Projections. Surface air temperature and precipitation change projections over regional and sub-regional scale are analyzed under the IPCC emission scenario (RCP8.5) for different seasons and homogeneous climatic zones over India. We analyze the spread in projections due to internal variability in the CESM-LE and CMIP5 datasets over these regions.

Some Take the Glass Escalator, Some Hit the Glass Ceiling? Career Consequences of Occupational Sex Segregation.

ERIC Educational Resources Information Center

Hultin, Mia

2003-01-01

Analysis of Swedish longitudinal data (1,535 men, 1,584 women) showed that men in female-dominated occupations have substantially better internal promotion opportunities than equally qualified women. In male-dominated occupations, men and women have equal internal promotion chances. Results suggest a "glass escalator" advantage for men…

Identification and selection for tuber calcium, internal quality and pitted scab in segregating ‘Atlantic’ x ‘Superior’ reciprocal tetraploid populations

USDA-ARS?s Scientific Manuscript database

Tuber quality traits are a major interest for breeders and the potato chip industry. This research intended to generate populations that can be suitable for the genetic study of tuber calcium, internal quality, common scab, and other commercially important traits such as yield, specific gravity and ...

A piecewise smooth model of evolutionary game for residential mobility and segregation

NASA Astrophysics Data System (ADS)

Radi, D.; Gardini, L.

2018-05-01

The paper proposes an evolutionary version of a Schelling-type dynamic system to model the patterns of residential segregation when two groups of people are involved. The payoff functions of agents are the individual preferences for integration which are empirically grounded. Differently from Schelling's model, where the limited levels of tolerance are the driving force of segregation, in the current setup agents benefit from integration. Despite the differences, the evolutionary model shows a dynamics of segregation that is qualitatively similar to the one of the classical Schelling's model: segregation is always a stable equilibrium, while equilibria of integration exist only for peculiar configurations of the payoff functions and their asymptotic stability is highly sensitive to parameter variations. Moreover, a rich variety of integrated dynamic behaviors can be observed. In particular, the dynamics of the evolutionary game is regulated by a one-dimensional piecewise smooth map with two kink points that is rigorously analyzed using techniques recently developed for piecewise smooth dynamical systems. The investigation reveals that when a stable internal equilibrium exists, the bimodal shape of the map leads to several different kinds of bifurcations, smooth, and border collision, in a complicated interplay. Our global analysis can give intuitions to be used by a social planner to maximize integration through social policies that manipulate people's preferences for integration.

Segregation and Disparities in Health Services Use

PubMed Central

Gaskin, Darrell J.; Price, Adrian; Brandon, Dwayne T.; LaVeist, Thomas A.

2011-01-01

We compared race disparities in health services use in a national sample of adults from the 2002 Medical Expenditure Panel Survey and data from the Exploring Health Disparities in Integrated Communities Project, a 2003 survey of adult residents from a low-income integrated urban community in Maryland. In the Medical Expenditure Panel Survey data, African Americans were less likely to have a health care visit compared with Whites. However, in the Exploring Health Disparities in Integrated Communities Project, the integrated community, African Americans were more likely to have a health care visit than Whites. The race disparities in the incidence rate of health care use among persons who had at least one visit were similar in both samples. Our findings suggest that disparities in health care utilization may differ across communities and that residential segregation may be a confounding factor. PMID:19460811

Low-pressure differentiation of tholeiitic lavas as recorded in segregation veins from Reykjanes (Iceland), Lanzarote (Canary Islands) and Masaya (Nicaragua)

NASA Astrophysics Data System (ADS)

Martin, E.; Sigmarsson, O.

2007-11-01

Segregation veins are common in lava sheets and result from internal differentiation during lava emplacement and degassing. They consist of evolved liquid, most likely replaced by gas-filter pressing from a ˜50% crystallised host lava. Pairs of samples, host lavas and associated segregation veins from the Reykjanes Peninsula (Iceland), Lanzarote (Canary Islands) and the Masaya volcano (Nicaragua) show extreme mineralogical and compositional variations (MgO in host lava, segregation veins and interstitial glass ranges from 8-10 wt%, 3-6 wt%, and to less than 0.01 wt%, respectively). These samples allow the assessment of the internal lava flow differentiation mechanism, since both the parental and derived liquid are known in addition to the last magma drops in the form of late interstitial glasses. The mineralogical variation, mass-balance calculated from major- and trace element composition, and transitional metal partition between crystals and melts are all consistent with fractional crystallisation as the dominant differentiation mechanism. The interstitial glasses are highly silicic (SiO2 = 70-80 wt%) and represent a final product of high-degree (75-97%) fractional crystallisation of olivine tholeiite at a pressure close to one atmosphere. The tholeiitic liquid-line-of-decent and the composition of the residual melts are governed by the K2O/Na2O of the initial basaltic magma. The granitic minimum is reached if the initial liquid has a high K2O/Na2O whereas trondhjemitic composition is the final product of magma with low initial K2O/Na2O.

DNA asymmetry in stem cells – immortal or mortal?

PubMed Central

Yadlapalli, Swathi; Yamashita, Yukiko M.

2013-01-01

Summary The immortal strand hypothesis proposes that stem cells retain a template copy of genomic DNA (i.e. an ‘immortal strand’) to avoid replication-induced mutations. An alternative hypothesis suggests that certain cells segregate sister chromatids non-randomly to transmit distinct epigenetic information. However, this area of research has been highly controversial, with conflicting data even from the same cell types. Moreover, historically, the same term of ‘non-random sister chromatid segregation’ or ‘biased sister chromatid segregation’ has been used to indicate distinct biological processes, generating a confusion in the biological significance and potential mechanism of each phenomenon. Here, we discuss the models of non-random sister chromatid segregation, and we explore the strengths and limitations of the various techniques and experimental model systems used to study this question. We also describe our recent study on Drosophila male germline stem cells, where sister chromatids of X and Y chromosomes are segregated non-randomly during cell division. We aim to integrate the existing evidence to speculate on the underlying mechanisms and biological relevance of this long-standing observation on non-random sister chromatid segregation. PMID:23970416

Recent advances in exploring the neural underpinnings of auditory scene perception

PubMed Central

Snyder, Joel S.; Elhilali, Mounya

2017-01-01

Studies of auditory scene analysis have traditionally relied on paradigms using artificial sounds—and conventional behavioral techniques—to elucidate how we perceptually segregate auditory objects or streams from each other. In the past few decades, however, there has been growing interest in uncovering the neural underpinnings of auditory segregation using human and animal neuroscience techniques, as well as computational modeling. This largely reflects the growth in the fields of cognitive neuroscience and computational neuroscience and has led to new theories of how the auditory system segregates sounds in complex arrays. The current review focuses on neural and computational studies of auditory scene perception published in the past few years. Following the progress that has been made in these studies, we describe (1) theoretical advances in our understanding of the most well-studied aspects of auditory scene perception, namely segregation of sequential patterns of sounds and concurrently presented sounds; (2) the diversification of topics and paradigms that have been investigated; and (3) how new neuroscience techniques (including invasive neurophysiology in awake humans, genotyping, and brain stimulation) have been used in this field. PMID:28199022

Modeling spatial segregation and travel cost influences on utilitarian walking: Towards policy intervention

PubMed Central

Yang, Yong; Auchincloss, Amy H.; Rodriguez, Daniel A.; Brown, Daniel G.; Riolo, Rick; Diez-Roux, Ana V.

2015-01-01

We develop an agent-based model of utilitarian walking and use the model to explore spatial and socioeconomic factors affecting adult utilitarian walking and how travel costs as well as various educational interventions aimed at changing attitudes can alter the prevalence of walking and income differentials in walking. The model is validated against US national data. We contrast realistic and extreme parameter values in our model and test effects of changing these parameters across various segregation and pricing scenarios while allowing for interactions between travel choice and place and for behavioral feedbacks. Results suggest that in addition to income differences in the perceived cost of time, the concentration of mixed land use (differential density of residences and businesses) are important determinants of income differences in walking (high income walk less), whereas safety from crime and income segregation on their own do not have large influences on income differences in walking. We also show the difficulty in altering walking behaviors for higher income groups who are insensitive to price and how adding to the cost of driving could increase the income differential in walking particularly in the context of segregation by income and land use. We show that strategies to decrease positive attitudes towards driving can interact synergistically with shifting cost structures to favor walking in increasing the percent of walking trips. Agent-based models, with their ability to capture dynamic processes and incorporate empirical data, are powerful tools to explore the influence on health behavior from multiple factors and test policy interventions. PMID:25733776

Measures Matter: The Local Exposure/Isolation (LEx/Is) Metrics and Relationships between Local-Level Segregation and Breast Cancer Survival.

PubMed

Bemanian, Amin; Beyer, Kirsten M M

2017-04-01

Background: The Black-to-White disparity in breast cancer survival is increasing, and racial residential segregation is a potential driver for this trend. However, study findings have been mixed, and no study has comprehensively compared the effectiveness of different local-level segregation metrics in explaining cancer survival. Methods: We proposed a set of new local segregation metrics named local exposure and isolation (LEx/Is) and compared our new local isolation metric with two related metrics, the location quotient (LQ) and the index of concentration at extremes (ICE), across the 102 largest U.S. metropolitan areas. Then, using case data from the Milwaukee, WI, metropolitan area, we used proportional hazards models to explore associations between segregation and breast cancer survival. Results: Across the 102 metropolitan areas, the new local isolation metric was less skewed than the LQ or ICE. Across all races, Hispanic isolation was associated with poorer all-cause survival, and Hispanic LQ and Hispanic-White ICE were found to be associated with poorer survival for both breast cancer-specific and all-cause mortality. For Black patients, Black LQ was associated with lower all-cause mortality and Black local isolation was associated with reduced all-cause and breast cancer-specific mortality. ICE was found to suffer from high multicollinearity. Conclusions: Local segregation is associated with breast cancer survival, but associations varied based on patient race and metric employed. Impact: We highlight how selection of a segregation measure can alter study findings. These relationships need to be validated in other geographic areas. Cancer Epidemiol Biomarkers Prev; 26(4); 516-24. ©2017 AACR See all the articles in this CEBP Focus section, "Geospatial Approaches to Cancer Control and Population Sciences." ©2017 American Association for Cancer Research.

Abiotic vs. biotic influences on habitat selection of coexisting species: Climate change impacts?

USGS Publications Warehouse

Martin, T.E.

2001-01-01

Species are commonly segregated along gradients of microclimate and vegetation. I explore the question of whether segregation is the result of microhabitat partitioning (biotic effects) or choice of differing microclimates (abiotic effects). I explored this question for four ground-nesting bird species that are segregated along a microclimate and vegetation gradient in Arizona. Birds shifted position of their nests on the microhabitat and microclimate gradient in response to changing precipitation over nine years. Similarly, annual bird abundance varied with precipitation across 12 yr. Those shifts in abundance and nesting microhabitat with changing precipitation demonstrate the importance of abiotic influences on bird distributions and habitat choice. However, nest-site shifts and microhabitat use also appear to be influenced by interactions among coexisting species. Moreover, shifts in habitat use by all species caused nest predation (i.e., biotic) costs that increased with increasing distance along the microclimate gradient. These results indicate that abiotic and biotic costs can strongly interact to influence microhabitat choice and abundances of coexisting species. Global climate change impacts have been considered largely in terms of simple distributional shifts, but these results indicate that shifts can also increase biotic costs when species move into habitat types for which they are poorly adapted or that create new biotic interactions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alessandrini, Emiliano; Lanzoni, Barbara; Ferraro, Francesco R.

We present the results of a set of N -body simulations aimed at exploring how the process of mass segregation (as traced by the spatial distribution of blue straggler stars, BSSs) is affected by the presence of a population of heavy dark remnants (as neutron stars and black holes (BHs)). To this end, clusters characterized by different initial concentrations and different fractions of dark remnants have been modeled. We find that an increasing fraction of stellar-mass BHs significantly delay the mass segregation of BSSs and the visible stellar component. In order to trace the evolution of BSS segregation, we introducemore » a new parameter ( A {sup +}), which can be easily measured when the cumulative radial distribution of these stars and a reference population are available. Our simulations show that A {sup +} might also be used as an approximate indicator of the time remaining to the core collapse of the visible component.« less

Sign Switch of Gaussian Bending Modulus for Microemulsions: A Self-Consistent Field Analysis Exploring Scale Invariant Curvature Energies

NASA Astrophysics Data System (ADS)

Varadharajan, Ramanathan; Leermakers, Frans A. M.

2018-01-01

Bending rigidities of tensionless balanced liquid-liquid interfaces as occurring in microemulsions are predicted using self-consistent field theory for molecularly inhomogeneous systems. Considering geometries with scale invariant curvature energies gives unambiguous bending rigidities for systems with fixed chemical potentials: the minimal surface I m 3 m cubic phase is used to find the Gaussian bending rigidity κ ¯, and a torus with Willmore energy W =2 π2 allows for direct evaluation of the mean bending modulus κ . Consistent with this, the spherical droplet gives access to 2 κ +κ ¯. We observe that κ ¯ tends to be negative for strong segregation and positive for weak segregation, a finding which is instrumental for understanding phase transitions from a lamellar to a spongelike microemulsion. Invariably, κ remains positive and increases with increasing strength of segregation.

Anomalous segregation dynamics of self-propelled particles

NASA Astrophysics Data System (ADS)

Mones, Enys; Czirók, András; Vicsek, Tamás

2015-06-01

A number of novel experimental and theoretical results have recently been obtained on active soft matter, demonstrating the various interesting universal and anomalous features of this kind of driven systems. Here we consider the adhesion difference-driven segregation of actively moving units, a fundamental but still poorly explored aspect of collective motility. In particular, we propose a model in which particles have a tendency to adhere through a mechanism which makes them both stay in touch and synchronize their direction of motion—but the interaction is limited to particles of the same kind. The calculations corresponding to the related differential equations can be made in parallel, thus a powerful GPU card allows large scale simulations. We find that in a very large system of particles, interacting without explicit alignment rule, three basic segregation regimes seem to exist as a function of time: (i) at the beginning the time dependence of the correlation length is analogous to that predicted by the Cahn-Hilliard theory, (ii) next rapid segregation occurs characterized with a separation of the different kinds of units being faster than any previously suggested speed, finally, (iii) the growth of the characteristic sizes in the system slows down due to a new regime in which self-confined, rotating, splitting and re-joining clusters appear. Our results can explain recent observations of segregating tissue cells in vitro.

Melt segregation from silicic crystal mushes: a critical appraisal of possible mechanisms and their microstructural record

NASA Astrophysics Data System (ADS)

Holness, Marian B.

2018-06-01

One of the outstanding problems in understanding the behavior of intermediate-to-silicic magmatic systems is the mechanism(s) by which large volumes of crystal-poor rhyolite can be extracted from crystal-rich mushy storage zones in the mid-deep crust. The mechanisms commonly invoked are hindered settling, micro-settling, and compaction. The concept of micro-settling involves extraction of grains from a crystal framework during Ostwald ripening and has been shown to be non-viable in the metallic systems for which it was originally proposed. Micro-settling is also likely to be insignificant in silicic mushes, because ripening rates are slow for quartz and plagioclase, contact areas between grains in a crystal mush are likely to be large, and abundant low-angle grain boundaries promote grain coalescence rather than ripening. Published calculations of melt segregation rates by hindered settling (Stokes settling in a crystal-rich system) neglect all but fluid dynamical interactions between particles. Because tabular silicate minerals are likely to form open, mechanically coherent, frameworks at porosities as high as 75%, settling of single crystals is only likely in very melt-rich systems. Gravitationally-driven viscous compaction requires deformation of crystals by either dissolution-reprecipitation or dislocation creep. There is, as yet, no reported microstructural evidence of extensive, syn-magmatic, internally-generated, viscous deformation in fully solidified silicic plutonic rocks. If subsequent directed searches do not reveal clear evidence for internally-generated buoyancy-driven melt segregation processes, it is likely that other factors, such as rejuvenation by magma replenishment, gas filter-pressing, or externally-imposed stress during regional deformation, are required to segregate large volumes of crystal-poor rhyolitic liquids from crustal mushy zones.

Cell segregation in the vertebrate hindbrain relies on actomyosin cables located at the interhombomeric boundaries

PubMed Central

Calzolari, Simone; Terriente, Javier; Pujades, Cristina

2014-01-01

Segregating cells into compartments during embryonic development is essential for growth and pattern formation. Physical mechanisms shaping compartment boundaries were recently explored in Drosophila, where actomyosin-based barriers were revealed to be important for keeping cells apart. In vertebrates, interhombomeric boundaries are straight interfaces, which often serve as signaling centers that pattern the surrounding tissue. Here, we demonstrate that in the hindbrain of zebrafish embryos cell sorting sharpens the molecular boundaries and, once borders are straight, actomyosin barriers are key to keeping rhombomeric cells segregated. Actomyosin cytoskeletal components are enriched at interhombomeric boundaries, forming cable-like structures in the apical side of the neuroepithelial cells by the time morphological boundaries are visible. When myosin II function is inhibited, cable structures do not form, leading to rhombomeric cell mixing. Downregulation of EphA4a compromises actomyosin cables and cells with different rhombomeric identity intermingle, and the phenotype is rescued enhancing myosin II activity. Moreover, enrichment of actomyosin structures is obtained when EphA4 is ectopically expressed in even-numbered rhombomeres. These findings suggest that mechanical barriers act downstream of EphA/ephrin signaling to segregate cells from different rhombomeres. PMID:24569501

Control of surface adatom kinetics for the growth of high-indium content InGaN throughout the miscibility gap

NASA Astrophysics Data System (ADS)

Moseley, Michael; Lowder, Jonathan; Billingsley, Daniel; Doolittle, W. Alan

2010-11-01

The surface kinetics of InGaN alloys grown via metal-modulated epitaxy (MME) are explored in combination with transient reflection high-energy electron diffraction intensities. A method for monitoring and controlling indium segregation in situ is demonstrated. It is found that indium segregation is more accurately associated with the quantity of excess adsorbed metal, rather than the metal-rich growth regime in general. A modified form of MME is developed in which the excess metal dose is managed via shuttered growth, and high-quality InGaN films throughout the miscibility gap are grown.

What We Know about School Choice.

ERIC Educational Resources Information Center

Froese-Germain, Bernie

1998-01-01

School choice is a market-driven reform in which schools compete for students. Discusses characteristics of choice and lessons drawn from the international experience: increased segregation, unimproved learning, low participation, parental criteria, inequity, lack of options, administrative emphasis on management, and right-wing support. Describes…

An Investigation of Spatial Hearing in Children with Normal Hearing and with Cochlear Implants and the Impact of Executive Function

NASA Astrophysics Data System (ADS)

Misurelli, Sara M.

The ability to analyze an "auditory scene"---that is, to selectively attend to a target source while simultaneously segregating and ignoring distracting information---is one of the most important and complex skills utilized by normal hearing (NH) adults. The NH adult auditory system and brain work rather well to segregate auditory sources in adverse environments. However, for some children and individuals with hearing loss, selectively attending to one source in noisy environments can be extremely challenging. In a normal auditory system, information arriving at each ear is integrated, and thus these binaural cues aid in speech understanding in noise. A growing number of individuals who are deaf now receive cochlear implants (CIs), which supply hearing through electrical stimulation to the auditory nerve. In particular, bilateral cochlear implants (BICIs) are now becoming more prevalent, especially in children. However, because CI sound processing lacks both fine structure cues and coordination between stimulation at the two ears, binaural cues may either be absent or inconsistent. For children with NH and with BiCIs, this difficulty in segregating sources is of particular concern because their learning and development commonly occurs within the context of complex auditory environments. This dissertation intends to explore and understand the ability of children with NH and with BiCIs to function in everyday noisy environments. The goals of this work are to (1) Investigate source segregation abilities in children with NH and with BiCIs; (2) Examine the effect of target-interferer similarity and the benefits of source segregation for children with NH and with BiCIs; (3) Investigate measures of executive function that may predict performance in complex and realistic auditory tasks of source segregation for listeners with NH; and (4) Examine source segregation abilities in NH listeners, from school-age to adults.

Sex segregation in undergraduate engineering majors

NASA Astrophysics Data System (ADS)

Litzler, Elizabeth

Gender inequality in engineering persists in spite of women reaching parity in college enrollments and degrees granted. To date, no analyses of educational sex segregation have comprehensively examined segregation within one discipline. To move beyond traditional methods of studying the long-standing stratification by field of study in higher education, I explore gender stratification within one field: engineering. This dissertation investigates why some engineering disciplines have a greater representation of women than other engineering disciplines. I assess the individual and institutional factors and conditions associated with women's representation in certain engineering departments and compare the mechanisms affecting women's and men's choice of majors. I use national data from the Engineering Workforce Commission, survey data from 21 schools in the Project to Assess Climate in Engineering study, and Carnegie Foundation classification information to study sex segregation in engineering majors from multiple perspectives: the individual, major, institution, and country. I utilize correlations, t-tests, cross-tabulations, log-linear modeling, multilevel logistic regression and weighted least squares regression to test the relative utility of alternative explanations for women's disproportionate representation across engineering majors. As a whole, the analyses illustrate the importance of context and environment for women's representation in engineering majors. Hypotheses regarding hostile climate and discrimination find wide support across different analyses, suggesting that women's under-representation in certain engineering majors is not a question of choice or ability. However, individual level factors such as having engineering coursework prior to college show an especially strong association with student choice of major. Overall, the analyses indicate that institutions matter, albeit less for women, and women's under-representation in engineering is not reducible to individual choice. This dissertation provides a broad, descriptive view of the state of sex segregation in engineering as well as a careful analysis of how individual and institutional factors inhibit or encourage sex segregation. This study contributes to the research literature through the use of novel data, testing of occupational segregation theories, and the use of multiple levels of analysis. The analyses provide new insight into an enduring phenomenon, and suggest new avenues for understanding sex segregation in higher education.

Neural organization and visual processing in the anterior optic tubercle of the honeybee brain.

PubMed

Mota, Theo; Yamagata, Nobuhiro; Giurfa, Martin; Gronenberg, Wulfila; Sandoz, Jean-Christophe

2011-08-10

The honeybee Apis mellifera represents a valuable model for studying the neural segregation and integration of visual information. Vision in honeybees has been extensively studied at the behavioral level and, to a lesser degree, at the physiological level using intracellular electrophysiological recordings of single neurons. However, our knowledge of visual processing in honeybees is still limited by the lack of functional studies of visual processing at the circuit level. Here we contribute to filling this gap by providing a neuroanatomical and neurophysiological characterization at the circuit level of a practically unstudied visual area of the bee brain, the anterior optic tubercle (AOTu). First, we analyzed the internal organization and neuronal connections of the AOTu. Second, we established a novel protocol for performing optophysiological recordings of visual circuit activity in the honeybee brain and studied the responses of AOTu interneurons during stimulation of distinct eye regions. Our neuroanatomical data show an intricate compartmentalization and connectivity of the AOTu, revealing a dorsoventral segregation of the visual input to the AOTu. Light stimuli presented in different parts of the visual field (dorsal, lateral, or ventral) induce distinct patterns of activation in AOTu output interneurons, retaining to some extent the dorsoventral input segregation revealed by our neuroanatomical data. In particular, activity patterns evoked by dorsal and ventral eye stimulation are clearly segregated into distinct AOTu subunits. Our results therefore suggest an involvement of the AOTu in the processing of dorsoventrally segregated visual information in the honeybee brain.

Effects of fullerene on lipid bilayers displaying different liquid ordering: a coarse-grained molecular dynamics study.

PubMed

Sastre, Judit; Mannelli, Ilaria; Reigada, Ramon

2017-11-01

The toxic effects and environmental impact of nanomaterials, and in particular of Fullerene particles, are matters of serious concern. It has been reported that fullerene molecules enter the cell membrane and occupy its hydrophobic region. Understanding the effects of carbon-based nanoparticles on biological membranes is therefore of critical importance to determine their exposure risks. We report on a systematic coarse-grained molecular dynamics study of the interaction of fullerene molecules with simple model cell membranes. We have analyzed bilayers consisting of lipid species with different degrees of unsaturation and a variety of cholesterol fractions. Addition of fullerene particles to phase-segregated ternary membranes is also investigated in the context of the lipid raft model for the organization of the cell membrane. Fullerene addition to lipid membranes modifies their structural properties like thickness, area and internal ordering of the lipid species, as well as dynamical aspects such as molecular diffusion and cholesterol flip-flop. Interestingly, we show that phase-segregating ternary lipid membranes accumulate fullerene molecules preferentially in the liquid-disordered domains promoting phase-segregation and domain alignment across the membrane. Lipid membrane internal ordering determines the behavior and distribution of fullerene particle, and this, in turn, determines the influence of fullerene on the membrane. Lipid membranes are good solvents of fullerene molecules, and in particular those with low internal ordering. Preference of fullerene molecules to be dissolved in the more disordered hydrophobic regions of a lipid bilayer and the consequent alteration of its phase behavior may have important consequences on the activity of biological cell membranes and on the bioconcentration of fullerene in living organisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Geographical Segregation of the Neurotoxin-Producing Cyanobacterium Anabaena circinalis

PubMed Central

Beltran, E. Carolina; Neilan, Brett A.

2000-01-01

Blooms of the cyanobacterium Anabaena circinalis are a major worldwide problem due to their production of a range of toxins, in particular the neurotoxins anatoxin-a and paralytic shellfish poisons (PSPs). Although there is a worldwide distribution of A. circinalis, there is a geographical segregation of neurotoxin production. American and European isolates of A. circinalis produce only anatoxin-a, while Australian isolates exclusively produce PSPs. The reason for this geographical segregation of neurotoxin production by A. circinalis is unknown. The phylogenetic structure of A. circinalis was determined by analyzing 16S rRNA gene sequences. A. circinalis was found to form a monophyletic group of international distribution. However, the PSP- and non-PSP-producing A. circinalis formed two distinct 16S rRNA gene clusters. A molecular probe was designed, allowing the identification of A. circinalis from cultured and uncultured environmental samples. In addition, probes targeting the predominantly PSP-producing or non-PSP-producing clusters were designed for the characterization of A. circinalis isolates as potential PSP producers. PMID:11010900

Amelogenesis Imperfecta: 1 Family, 2 Phenotypes, and 2 Mutated Genes.

PubMed

Prasad, M K; Laouina, S; El Alloussi, M; Dollfus, H; Bloch-Zupan, A

2016-12-01

Amelogenesis imperfecta (AI) is a clinically and genetically heterogeneous group of diseases characterized by enamel defects. The authors have identified a large consanguineous Moroccan family segregating different clinical subtypes of hypoplastic and hypomineralized AI in different individuals within the family. Using targeted next-generation sequencing, the authors identified a novel heterozygous nonsense mutation in COL17A1 (c.1873C>T, p.R625*) segregating with hypoplastic AI and a novel homozygous 8-bp deletion in C4orf26 (c.39_46del, p.Cys14Glyfs*18) segregating with hypomineralized-hypoplastic AI in this family. This study highlights the phenotypic and genotypic heterogeneity of AI that can exist even within a single consanguineous family. Furthermore, the identification of novel mutations in COL17A1 and C4orf26 and their correlation with distinct AI phenotypes can contribute to a better understanding of the pathophysiology of AI and the contribution of these genes to amelogenesis. © International & American Associations for Dental Research 2016.

How Internally Coupled Ears Generate Temporal and Amplitude Cues for Sound Localization.

PubMed

Vedurmudi, A P; Goulet, J; Christensen-Dalsgaard, J; Young, B A; Williams, R; van Hemmen, J L

2016-01-15

In internally coupled ears, displacement of one eardrum creates pressure waves that propagate through air-filled passages in the skull and cause displacement of the opposing eardrum, and conversely. By modeling the membrane, passages, and propagating pressure waves, we show that internally coupled ears generate unique amplitude and temporal cues for sound localization. The magnitudes of both these cues are directionally dependent. The tympanic fundamental frequency segregates a low-frequency regime with constant time-difference magnification from a high-frequency domain with considerable amplitude magnification.

A Model for Siderophile Element Distribution in Planetary Differentiation

NASA Technical Reports Server (NTRS)

Humayun, M.; Rushmer, T.; Rankenburg, K.; Brandon, A. D.

2005-01-01

Planetary differentiation begins with partial melting of small planetesimals. At low degrees of partial melting, a sulfur-rich liquid segregates by physical mechanisms including deformation-assisted porous flow. Experimental studies of the physical mechanisms by which Fe-S melts segregate from the silicate matrix of a molten H chondrite are part of a companion paper. Geochemical studies of these experimental products revealed that metallic liquids were in equilibrium with residual metal in the H chondrite matrix. This contribution explores the geochemical signatures produced by early stages of core formation. Particularly, low-degree partial melt segregation of Fe-S liquids leaves residual metal in the silicate matrix. Some achondrites appear to be residues of partial melting, e.g., ureilites, which are known to contain metal. The metal in these achondrites may show a distinct elemental signature. To quantify the effect of sulfur on siderophile element contents of residual metal we have developed a model based on recent parametrizations of equilibrium solid metal-liquid metal partitioning experiments.

Protein Mixture Segregation at Coffee-Ring: Real-Time Imaging of Protein Ring Precipitation by FTIR Spectromicroscopy.

PubMed

Choi, Sun; Birarda, Giovanni

2017-08-03

During natural drying process, all solutions and suspensions tend to form the so-called "coffee-ring" deposits. This phenomenon, by far, has been interpreted by the hydrodynamics of evaporating fluids. However, in this study, by applying Fourier transform infrared imaging (FTIRI), it is possible to observe the segregation and separation of a protein mixture at the "ring", hence we suggest a new way to interpret "coffee-ring effect" of solutions. The results explore the dynamic process that leads to the ring formation in case of model plasma proteins, such as BGG (bovine γ globulin), BSA (bovine serum albumin), and Hfib (human fibrinogen), and also report fascinating discovery of the segregation at the ring deposits of two model proteins BGG and BSA, which can be explained by an energy kinetic model, only. The investigation suggests that the coffee-ring effect of solute in an evaporating solution drop is driven by an energy gradient created from change of particle-water-air interfacial energy configuration.

Gender Matters for Literacy Research Organizations

ERIC Educational Resources Information Center

Wickens, Corrine M.

2018-01-01

Drawing from sociological and economic analyses of gender and work, this column explores issues of occupational gender segregation, privilege, and devaluation. Comparisons are made with increased female achievement at all levels in postsecondary education. The questions are then raised: If cultural devaluation of women and activities remains…

Assessment of Intergenerational Communication and Relationships

ERIC Educational Resources Information Center

Strom, Robert D.; Strom, Paris S.

2015-01-01

The revolution in communication technology has resulted in more age-segregated conversation among adolescents. In a similar way, older adults have increased online conversations with their peers. This article explores some obstacles that prevent the intergenerational connections needed for mutual understanding and care. Several research emphases…

Can Architecture Design Solve Social Problem?

NASA Astrophysics Data System (ADS)

Ginting, S. W.; TSB Darjosanjoto, E.; Sulistyarso, H.

2017-03-01

Most of architects and urban designers believe physical design gives impact on our social life. For example, a sign or landmark in the middle of a city makes people find orientation easier. In vice verse, most of social scientists believe it is social dynamic that plays role in shaping our space. How people spend their time moving from real space into cyber space is a proof that life style and IT give impact to space usage. This paper argues that interaction between physical design and social change is a two ways process. Both design aspect and social dynamic influence each other. This paper aims to examine how designing of gated community plays important role in increasing or decreasing segregation, both spatially and socially. The paper explores some architectural design principles applied in a gated community called CitraLand in west Surabaya, Indonesia, and addresses segregation between CitraLanders and outside kampung. We find CitraLand is designed openly and fully accessible for outsiders. It provides public spaces and several accessible gates and streets without walls and fences making all places inside and outside CitraLand spatially integrated. What’s interesting is it still reinforces social segregation due to its policy on prohibiting using the public park. We believe CitraLand’s planning and designing has successfully solved segregation problem spatially not socially.

Effect of the Large Scale Environment on the Internal Dynamics of Early-Type Galaxies

NASA Astrophysics Data System (ADS)

Maubon, G.; Prugniel, Ph.

We have studied the population-density relation in very sparse environments, from poor clusters to isolated galaxies, and we find that early-type galaxies with a young stellar population are preferably found in the lowest density environments. We show a marginal indication that this effect is due to an enhancement of the stellar formation independent of the morphological segregation, but we failed to find any effect from the internal dynamics.

Sex role segregation and mixing among men who have sex with men: implications for biomedical HIV prevention interventions.

PubMed

Armbruster, Benjamin; Roy, Sourya; Kapur, Abhinav; Schneider, John A

2013-01-01

Men who have sex with men (MSM) practice role segregation - insertive or receptive only sex positions instead of a versatile role - in several international settings where candidate biomedical HIV prevention interventions (e.g., circumcision, anal microbicide) will be tested. The effects of these position-specific interventions on HIV incidence are modeled. We developed a deterministic compartmental model to predict HIV incidence among Indian MSM using data from 2003-2010. The model's sex mixing matrix was derived from network data of Indian MSM (n=4604). Our model captures changing distribution of sex roles over time. We modeled microbicide and circumcision efficacy on trials with heterosexuals. Increasing numbers of versatile MSM resulted in little change in HIV incidence over 20 years. Anal microbicides and circumcision would decrease the HIV prevalence at 10 years from 15.6% to 12.9% and 12.7% respectively. Anal microbicides would provide similar protection to circumcision at the population level despite lower modeled efficacy (54% and 60% risk reduction, respectively). Combination of the interventions were additive: in 5 years, the reduction in HIV prevalence of the combination (-3.2%) is almost the sum of their individual reductions in HIV prevalence (-1.8% and -1.7%). MSM sex role segregation and mixing, unlike changes in the sex role distribution, may be important for evaluating HIV prevention interventions in international settings. Synergies between some position-specific prevention interventions such as circumcision and anal microbicides warrant further study.

Military Policy toward Homosexuals: Scientific, Historic, and Legal Perspectives

DTIC Science & Technology

1990-04-01

International Trends During the 1950s, the American Law Institute recommended that states adopt a Model Penal Code that decriminalized all non-violent...personalities. For much of our history, the military’s fear of racial tension kept black soldiers segregated from whites. Fear of sexual tensions, until

A Lingering Miseducation: Confronting the Legacy of "Little Tree."

ERIC Educational Resources Information Center

Justice, Daniel Heath

2000-01-01

The popular book, "The Education of Little Tree," written by a Ku Klux Klansman, perpetuates popular stereotypes about American Indians and advances the author's ideology about segregation and staunch individualism. This type of fraud is especially damaging to children, both White and Indian, who internalize such stereotypes as more…

Children with Intellectual Disabilities and Special School Education in Ghana

ERIC Educational Resources Information Center

Kassah, Bente Lilljan Lind; Kassah, Alexander Kwesi; Phillips, Deborah

2018-01-01

Even though Ghana has embraced international calls for mainstream education, many children with intellectual disabilities still receive education in segregated special schools. This article discusses the views of seven informants on the importance of special schools in Ghana. After securing the consent of our informants, we conducted in-depth…

Neural signature of coma revealed by posteromedial cortex connection density analysis.

PubMed

Malagurski, Briguita; Péran, Patrice; Sarton, Benjamine; Riu, Beatrice; Gonzalez, Leslie; Vardon-Bounes, Fanny; Seguin, Thierry; Geeraerts, Thomas; Fourcade, Olivier; de Pasquale, Francesco; Silva, Stein

2017-01-01

Posteromedial cortex (PMC) is a highly segregated and dynamic core, which appears to play a critical role in internally/externally directed cognitive processes, including conscious awareness. Nevertheless, neuroimaging studies on acquired disorders of consciousness, have traditionally explored PMC as a homogenous and indivisible structure. We suggest that a fine-grained description of intrinsic PMC topology during coma, could expand our understanding about how this cortical hub contributes to consciousness generation and maintain, and could permit the identification of specific markers related to brain injury mechanism and useful for neurological prognostication. To explore this, we used a recently developed voxel-based unbiased approach, named functional connectivity density (CD). We compared 27 comatose patients (15 traumatic and 12 anoxic), to 14 age-matched healthy controls. The patients' outcome was assessed 3 months later using Coma Recovery Scale-Revised (CRS-R). A complex pattern of decreased and increased connections was observed, suggesting a network imbalance between internal/external processing systems, within PMC during coma. The number of PMC voxels with hypo-CD positive correlation showed a significant negative association with the CRS-R score, notwithstanding aetiology. Traumatic injury specifically appeared to be associated with a greater prevalence of hyper-connected (negative correlation) voxels, which was inversely associated with patient neurological outcome. A logistic regression model using the number of hypo-CD positive and hyper-CD negative correlations, accurately permitted patient's outcome prediction (AUC = 0.906, 95%IC = 0.795-1). These points might reflect adaptive plasticity mechanism and pave the way for innovative prognosis and therapeutics methods.

Race, Remembering, and Jim Crow's Teachers. Studies in African American History and Culture

ERIC Educational Resources Information Center

Kelly, Hilton

2012-01-01

This book explores a profoundly negative narrative about legally segregated schools in the United States being "inherently inferior" compared to their white counterparts. However, there are overwhelmingly positive counter-memories of these schools as "good and valued" among former students, teachers, and community members.…

Exploring South African Mathematics Teachers' Experiences of Learner Migration

ERIC Educational Resources Information Center

Robertson, Sally-Ann; Graven, Mellony

2015-01-01

This paper focuses on patterns of post-apartheid learner migration between schools previously segregated along racial lines. South Africa's shift away from cultural and linguistic isolationism and the ways this has impacted educational arrangements in this country, most particularly in relation to the language of learning and teaching, affects…

How to Improve Adolescents' Sun Protection Behavior? Age and Gender Issues

ERIC Educational Resources Information Center

Paul, Christine; Tzelepis, Flora; Parfitt, Nicholas; Girgis, Afaf

2008-01-01

Objective: To explore adolescents' self-reported reasons for sun protection, as adolescents as a group continue to have poor sun protection practices. Methods: Seventeen age- and gender-segregated focus groups were conducted in Australian high schools. Results: Reasons for using sun protection included personal comfort, appearance, policies, fear…

Bullying Risk in Children with Learning Difficulties in Inclusive Educational Settings

ERIC Educational Resources Information Center

Luciano, Severina; Savage, Robert S.

2007-01-01

This study investigated whether students with learning difficulties (LDs) attending inclusive schools that eschewed segregated "pull out" programs reported more incidents of being bullied than their peers without LDs. Cognitive and self-perception factors associated with reports of peer victimization were also explored. Participants were…

The Sociology of Urban Education: Desegregation and Integration.

ERIC Educational Resources Information Center

Willie, Charles Vert

In this book, the problems of racial segregation and desegregation in urban schools and colleges are discussed in light of cultural, biological, and social questions. Part I explores various issues in urban education, such as racial balance and quality education, white flight, community control, the city-suburban connection, education for the…

Positioning and Latinas/os: A Study of Small-Group Interactions in Mathematics

ERIC Educational Resources Information Center

Lopez Leiva, Carlos Alfonso

2011-01-01

This study explores social interaction and mathematics performance, especially regarding how bilingual Latino/a students' positioning and participation evolved as they interacted with others in mathematics problem solving. Historically, Latinas/os have faced segregation in different ways that affect the quality of their social interactions…

Choosing Charters: Better Schools or More Segregation?

ERIC Educational Resources Information Center

Rotberg, Iris C., Ed.; Glazer, Joshua L., Ed.

2018-01-01

Do charter schools strengthen students' educational experience? What are their social costs? This volume brings together a group of premier researchers to address questions about the purposes of charter schools and the role of public policy in shaping the educational agenda. Chapter authors explore topics seldom encountered in the current charter…

Mobilities of Youth: Social and Spatial Trajectories in a Segregated Sweden

ERIC Educational Resources Information Center

Lindgren, Joakim; Lundahl, Lisbeth

2010-01-01

This article explores youth mobilities in three geographic and socio-economically diverse Swedish contexts. The concept of mobility has become an important feature of individualistic discourses of responsibility relating to inclusion, lifelong learning and self-regulating entrepreneurial behaviour. This article draws attention to the fact that…

Proving the Viability of a School Choice Voucher. Policy Brief

ERIC Educational Resources Information Center

Haller, Scott

2015-01-01

A recent Pioneer Institute report written by Ken Ardon and Cara Stilling Candal, "Modeling Urban Scholarship Vouchers in Massachusetts," explores the viability of a school choice voucher program in the Commonwealth. Nationally, school choice has been shown to improve parent satisfaction and student achievement, reduce racial segregation,…

Differential Phytosociological Interactions Involving Male and Female Atriplex bonnevillensis

USDA-ARS?s Scientific Manuscript database

Males and females of wind-pollinated dioecious plants often exhibit spatial segregation of the sexes. This partial niche separation has most often been explored using abiotic niche axes. If the sexes are truly separated in space then they are apt to encounter different species and, to the extent tha...

Protein interactions and ligand binding: from protein subfamilies to functional specificity.

PubMed

Rausell, Antonio; Juan, David; Pazos, Florencio; Valencia, Alfonso

2010-02-02

The divergence accumulated during the evolution of protein families translates into their internal organization as subfamilies, and it is directly reflected in the characteristic patterns of differentially conserved residues. These specifically conserved positions in protein subfamilies are known as "specificity determining positions" (SDPs). Previous studies have limited their analysis to the study of the relationship between these positions and ligand-binding specificity, demonstrating significant yet limited predictive capacity. We have systematically extended this observation to include the role of differential protein interactions in the segregation of protein subfamilies and explored in detail the structural distribution of SDPs at protein interfaces. Our results show the extensive influence of protein interactions in the evolution of protein families and the widespread association of SDPs with protein interfaces. The combined analysis of SDPs in interfaces and ligand-binding sites provides a more complete picture of the organization of protein families, constituting the necessary framework for a large scale analysis of the evolution of protein function.

Cortical connectivity in fronto-temporal focal epilepsy from EEG analysis: A study via graph theory.

PubMed

Vecchio, Fabrizio; Miraglia, Francesca; Curcio, Giuseppe; Della Marca, Giacomo; Vollono, Catello; Mazzucchi, Edoardo; Bramanti, Placido; Rossini, Paolo Maria

2015-06-01

It is believed that effective connectivity and optimal network structure are essential for proper information processing in the brain. Indeed, functional abnormalities of the brain are found to be associated with pathological changes in connectivity and network structures. The aim of the present study was to explore the interictal network properties of EEG signals from temporal lobe structures in the context of fronto-temporal lobe epilepsy. To complete this aim, the graph characteristics of the EEG data of 17 patients suffering from focal epilepsy of the fronto-temporal type, recorded during interictal periods, were examined and compared in terms of the affected versus the unaffected hemispheres. EEG connectivity analysis was performed using eLORETA software in 15 fronto-temporal regions (Brodmann Areas BAs 8, 9, 10, 11, 20, 21, 22, 37, 38, 41, 42, 44, 45, 46, 47) on both affected and unaffected hemispheres. The evaluation of the graph analysis parameters, such as 'global' (characteristic path length) and 'local' connectivity (clustering coefficient) showed a statistically significant interaction among side (affected and unaffected hemisphere) and Band (delta, theta, alpha, beta, gamma). Duncan post hoc testing showed an increase of the path length in the alpha band in the affected hemisphere with respect to the unaffected one, as evaluated by an inter-hemispheric marker. The affected hemisphere also showed higher values of local connectivity in the alpha band. In general, an increase of local and global graph theory parameters in the alpha band was found in the affected hemisphere. It was also demonstrated that these effects were more evident in drug-free patients than in those undergoing pharmacological therapy. The increased measures in the affected hemisphere of both functional local segregation and global integration could result from the combination of overlapping mechanisms, including reactive neuroplastic changes seeking to maintain constant integration and segregation properties. This reactive neuroplastic mechanism seeking to maintain constant integration and segregation properties seems to be more evident in the absence of antiepileptic treatment. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

The functional significance of velocity storage and its dependence on gravity.

PubMed

Laurens, Jean; Angelaki, Dora E

2011-05-01

Research in the vestibular field has revealed the existence of a central process, called 'velocity storage', that is activated by both visual and vestibular rotation cues and is modified by gravity, but whose functional relevance during natural motion has often been questioned. In this review, we explore spatial orientation in the context of a Bayesian model of vestibular information processing. In this framework, deficiencies/ambiguities in the peripheral vestibular sensors are compensated for by central processing to more accurately estimate rotation velocity, orientation relative to gravity, and inertial motion. First, an inverse model of semicircular canal dynamics is used to reconstruct rotation velocity by integrating canal signals over time. However, its low-frequency bandwidth is limited to avoid accumulation of noise in the integrator. A second internal model uses this reconstructed rotation velocity to compute an internal estimate of tilt and inertial acceleration. The bandwidth of this second internal model is also restricted at low frequencies to avoid noise accumulation and drift of the tilt/translation estimator over time. As a result, low-frequency translation can be erroneously misinterpreted as tilt. The time constants of these two integrators (internal models) can be conceptualized as two Bayesian priors of zero rotation velocity and zero linear acceleration, respectively. The model replicates empirical observations like 'velocity storage' and 'frequency segregation' and explains spatial orientation (e.g., 'somatogravic') illusions. Importantly, the functional significance of this network, including velocity storage, is found during short-lasting, natural head movements, rather than at low frequencies with which it has been traditionally studied.

The role of proximal social contexts: Assessing stigma-by-association effects on leader appraisals.

PubMed

Hernandez, Morela; Avery, Derek R; Tonidandel, Scott; Hebl, Mikki R; Smith, Alexis N; McKay, Patrick F

2016-01-01

Prior research suggests that segregation in the U.S. workplace is on the rise (Hellerstein, Neumark, & McInerney, 2008); as such, leaders are more likely to lead groups of followers composed primarily of their own race (Elliot & Smith, 2001; Smith & Elliott, 2002). Drawing from theory on stigma-by-association, the authors posit that such segregated proximal social contexts (i.e., the leader's group of followers) can have detrimental effects on leader appraisals. Specifically, they argue that leaders of mostly Black follower groups experience stigmatization based on race stereotypic beliefs, which affects how they are viewed in the eyes of observers. The results of a large field study show performance evaluations generally tend to be lower when the proportion of Black followers is higher. Moreover, 3 experiments demonstrate that the impact of proximal social contexts extends to other outcomes (i.e., perceptions of market value and competency) but appears limited to those who are less internally and externally motivated to control their prejudice. Taken together, these findings explain how workplace segregation systematically can create a particular disadvantage for Black leaders. (c) 2016 APA, all rights reserved).

The Politics of Racial Disparities: Desegregating the Hospitals in Jackson, Mississippi

PubMed Central

Smith, David Barton

2005-01-01

As health care policymakers and providers focus on eliminating the persistent racial disparities in treatment, it is useful to explore how resistance to hospital desegregation was overcome. Jackson, Mississippi, provides an instructive case study of how largely concealed deliberations achieved the necessary concessions in a still rigidly segregated community. The Veterans Administration hospital, the medical school hospital, and the private nonprofit facilities were successively desegregated, owing mainly to the threatened loss of federal dollars. Many of the changes, however, were cosmetic. In contrast to the powerful financial incentives offered to hospitals to desegregate and ensure equal access in the early years of the Medicare program, current trends in federal reimbursement encourage segregation and disparities in treatment. PMID:15960771

Thin film self-assembly of PVMS-b-PMMA block copolymer

NASA Astrophysics Data System (ADS)

Lwoya, Baraka; Uddin, Md; Chatterjee, Sourav; Albert, Julie

Self-assembly of block copolymers has been explored for numerous years with a primary emphasis on nanolithographic templates and membrane applications. Block copolymers (BCPs) hold great promise as next-generation patterning materials for sub-10 nm nano-electronic applications. However, the inherent properties to develop smaller more ordered thin films ( 10-100 nm) is greatly hindered by the inability of the low segregation strength of conventional polymers such as poly(styrene-block-methylmethacrylate). We aim at addressing this issue by firstly synthesizing strongly segregating BCPs of poly(vinylmethylsiloxane-block-methyl methacrylate) (PVMS- b - PMMA) with different block volume fractions. Second, we induce self-assembly by either thermal or solvent annealing and characterize the morphology by atomic force microscopy (AFM). In addition, the use of a block with a pendant vinyl group provides the ability to functionalize the PVMS segment by thiol-ene reaction, either to further control of the segregation strength or to impart desirable surface chemical properties (e.g., adhesion/lift-off in templating or functionality in membranes). Gulf Research Program Early-Career Research Fellowship.

Predicted trends of core-shell preferences for 132 late transition-metal binary-alloy nanoparticles.

PubMed

Wang, Lin-Lin; Johnson, Duane D

2009-10-07

Transition-metal alloyed nanoparticles with core-shell features (shell enrichment by one of the metals) are becoming ubiquitous, from (electro-)catalysis to biomedical applications, due to their size control, performance, biocompatibility, and cost. We investigate 132 binary-alloyed nanoparticle systems (groups 8 to 11 in the Periodic Table) using density functional theory (DFT) and systematically explore their segregation energies to determine core-shell preferences. We find that core-shell preferences are generally described by two independent factors: (1) cohesive energy (related to vapor pressure) and (2) atomic size (quantified by the Wigner-Seitz radius), and the interplay between them. These independent factors are shown to provide general trends for the surface segregation preference for atoms in nanoparticles, as well as semi-infinite surfaces, and give a simple correlation (a "design map") for the alloying and catalytic behavior. Finally, we provide a universal description of core-shell preference via tight-binding theory (band-energy differences) that (i) quantitatively reproduces the DFT segregation energies and (ii) confirms the electronic origins and correlations for core-shell behavior.

26 CFR 301.7507-9 - Termination of immunity.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 18 2011-04-01 2011-04-01 false Termination of immunity. 301.7507-9 Section 301... Termination of immunity. (a) In general. (1) In the case of a bank within section 7507(a), immunity will end... depositors. Immunity of a bank within section 7507 (b) is terminated, as to segregated assets, whenever...

26 CFR 301.7507-7 - Establishment of immunity.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 18 2012-04-01 2012-04-01 false Establishment of immunity. 301.7507-7 Section... States § 301.7507-7 Establishment of immunity. (a) The mere allegation of insolvency, or that depositors have claims against segregated or other assets or earnings, will not of itself secure immunity from tax...

26 CFR 301.7507-9 - Termination of immunity.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Termination of immunity. 301.7507-9 Section 301... Termination of immunity. (a) In general. (1) In the case of a bank within section 7507(a), immunity will end... depositors. Immunity of a bank within section 7507 (b) is terminated, as to segregated assets, whenever...

26 CFR 301.7507-9 - Termination of immunity.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 18 2012-04-01 2012-04-01 false Termination of immunity. 301.7507-9 Section 301... Termination of immunity. (a) In general. (1) In the case of a bank within section 7507(a), immunity will end... depositors. Immunity of a bank within section 7507 (b) is terminated, as to segregated assets, whenever...

26 CFR 301.7507-9 - Termination of immunity.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 18 2013-04-01 2013-04-01 false Termination of immunity. 301.7507-9 Section 301... Termination of immunity. (a) In general. (1) In the case of a bank within section 7507(a), immunity will end... depositors. Immunity of a bank within section 7507 (b) is terminated, as to segregated assets, whenever...

26 CFR 301.7507-7 - Establishment of immunity.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Establishment of immunity. 301.7507-7 Section... States § 301.7507-7 Establishment of immunity. (a) The mere allegation of insolvency, or that depositors have claims against segregated or other assets or earnings, will not of itself secure immunity from tax...

26 CFR 301.7507-7 - Establishment of immunity.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 18 2013-04-01 2013-04-01 false Establishment of immunity. 301.7507-7 Section... States § 301.7507-7 Establishment of immunity. (a) The mere allegation of insolvency, or that depositors have claims against segregated or other assets or earnings, will not of itself secure immunity from tax...

26 CFR 301.7507-7 - Establishment of immunity.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 18 2014-04-01 2014-04-01 false Establishment of immunity. 301.7507-7 Section... States § 301.7507-7 Establishment of immunity. (a) The mere allegation of insolvency, or that depositors have claims against segregated or other assets or earnings, will not of itself secure immunity from tax...

26 CFR 301.7507-7 - Establishment of immunity.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 18 2011-04-01 2011-04-01 false Establishment of immunity. 301.7507-7 Section... States § 301.7507-7 Establishment of immunity. (a) The mere allegation of insolvency, or that depositors have claims against segregated or other assets or earnings, will not of itself secure immunity from tax...

26 CFR 301.7507-9 - Termination of immunity.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 18 2014-04-01 2014-04-01 false Termination of immunity. 301.7507-9 Section 301... Termination of immunity. (a) In general. (1) In the case of a bank within section 7507(a), immunity will end... depositors. Immunity of a bank within section 7507 (b) is terminated, as to segregated assets, whenever...

Equity and Segregation in the Spanish Education System

ERIC Educational Resources Information Center

Ferrer, Ferran; Ferrer, Gerard; Baldellou, Jose Luis Castel

2006-01-01

This article discusses educational inequalities within the territorial context of Spain, and more particularly in the autonomous community of Catalonia. The analysis, which takes a comparative international approach, looks at the question from two points of view. First, from the angle of students, an analysis is made of the impact produced by…

25 CFR 542.16 - What are the minimum internal control standards for information technology?

Code of Federal Regulations, 2011 CFR

2011-04-01

... information technology? 542.16 Section 542.16 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE... standards for information technology? Link to an amendment published at 73 FR 60498, Oct. 10, 2008. This... adequately segregated and monitored to prevent error in general information technology procedures to go...

25 CFR 542.16 - What are the minimum internal control standards for information technology?

Code of Federal Regulations, 2010 CFR

2010-04-01

... information technology? 542.16 Section 542.16 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE... standards for information technology? Link to an amendment published at 73 FR 60498, Oct. 10, 2008. This... adequately segregated and monitored to prevent error in general information technology procedures to go...

Multistage Core Formation in Planetesimals Revealed by Numerical Modeling and Hf-W Chronometry of Iron Meteorites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neumann, W.; Kruijer, T. S.; Breuer, D.

Iron meteorites provide some of the most direct insights into the processes and timescales of core formation in planetesimals. Of these, group IVB irons stand out by having one of the youngest 182Hf- 182W model ages for metal segregation (2.9 ± 0.6 Ma after solar system formation), as well as the lowest bulk sulfur content and hence highest liquidus temperature. Here in this paper, using a new model for the internal evolution of the IVB parent body, we show that a single stage of metal-silicate separation cannot account for the complete melting of pure Fe metal at the relatively latemore » time given by the Hf-W model age. Instead, a complex metal-silicate separation scenario is required that includes migration of partial silicate melts, formation of a shallow magma ocean, and core formation in two distinct stages of metal segregation. In the first stage, a protocore formed at ≈1.5 Ma via settling of metal particles in a mantle magma ocean, followed by metal segregation from a shallow magma ocean at ≈5.4 Ma. As these stages of metal segregation occurred at different times, the two metal fractions had different 182W compositions. Consequently, the final 182W composition of the IVB core does not correspond to a single differentiation event, but represents the average composition of early- and late-segregated core fractions. Our best fit model indicates an ≈100 km radius for the IVB parent body and provides an accretion age of ≈0.1–0.5 Ma after solar system formation. The computed solidification time is, furthermore, consistent with the Re-Os age for crystallization of the IVB core.« less

Multistage Core Formation in Planetesimals Revealed by Numerical Modeling and Hf-W Chronometry of Iron Meteorites

DOE PAGES

Neumann, W.; Kruijer, T. S.; Breuer, D.; ...

2018-02-01

Iron meteorites provide some of the most direct insights into the processes and timescales of core formation in planetesimals. Of these, group IVB irons stand out by having one of the youngest 182Hf- 182W model ages for metal segregation (2.9 ± 0.6 Ma after solar system formation), as well as the lowest bulk sulfur content and hence highest liquidus temperature. Here in this paper, using a new model for the internal evolution of the IVB parent body, we show that a single stage of metal-silicate separation cannot account for the complete melting of pure Fe metal at the relatively latemore » time given by the Hf-W model age. Instead, a complex metal-silicate separation scenario is required that includes migration of partial silicate melts, formation of a shallow magma ocean, and core formation in two distinct stages of metal segregation. In the first stage, a protocore formed at ≈1.5 Ma via settling of metal particles in a mantle magma ocean, followed by metal segregation from a shallow magma ocean at ≈5.4 Ma. As these stages of metal segregation occurred at different times, the two metal fractions had different 182W compositions. Consequently, the final 182W composition of the IVB core does not correspond to a single differentiation event, but represents the average composition of early- and late-segregated core fractions. Our best fit model indicates an ≈100 km radius for the IVB parent body and provides an accretion age of ≈0.1–0.5 Ma after solar system formation. The computed solidification time is, furthermore, consistent with the Re-Os age for crystallization of the IVB core.« less

Core segregation mechanism and compositional evolution of terretrial planets

NASA Astrophysics Data System (ADS)

Petford, N.; Rushmer, T.

2009-04-01

A singular event in the formation of the earth and terrestrial planets was the separation iron-rich melt from mantle silicate to form planetary cores. On Earth, and by implication other rocky planets, this process induced profound internal chemical fractionation, with siderophile elements (Ni, Co, Au, Pt, W, Re) following Fe into the core, leaving the silicate crust and mantle with strong depletions of these elements relative to primitive planetary material. Recent measurements of radiogenic 182W anomalies in the silicate Earth, Mars and differentiated meteorites imply that planetesimals segregated metallic cores within a few Myr of the origin of the solar system. Various models have been put forward to explain the physical nature of the segregation mechanism (Fe-diapirs, ‘raining' through a magma ocean), and more recently melt flow via fractures. In this contribution we present the initial results of a numerical study into Fe segregation in a deforming silicate matrix that captures the temperature-dependent effect of liquid metal viscosity on the transport rate. Flow is driven by pressure gradients associated with impact deformation in a growing planetesimal and the fracture geometry is constrained by experimental data on naturally deformed H6 chondrite. Early results suggest that under dynamic conditions, fracture-driven melt flow can in principle be extremely rapid, leading to a significant draining of the Fe-liquid metal and siderophile trace element component on a timescale of hours to days. Fluid transport in planetesimals where deformation is the driving force provides an attractive and simple way of segregating Fe from host silicate as both precursor and primary agent of core formation. The potential for flow of metal-rich melt to induce local magnetic anomalies will also be addressed.

Multistage Core Formation in Planetesimals Revealed by Numerical Modeling and Hf-W Chronometry of Iron Meteorites

NASA Astrophysics Data System (ADS)

Neumann, W.; Kruijer, T. S.; Breuer, D.; Kleine, T.

2018-02-01

Iron meteorites provide some of the most direct insights into the processes and timescales of core formation in planetesimals. Of these, group IVB irons stand out by having one of the youngest 182Hf-182W model ages for metal segregation (2.9 ± 0.6 Ma after solar system formation), as well as the lowest bulk sulfur content and hence highest liquidus temperature. Here, using a new model for the internal evolution of the IVB parent body, we show that a single stage of metal-silicate separation cannot account for the complete melting of pure Fe metal at the relatively late time given by the Hf-W model age. Instead, a complex metal-silicate separation scenario is required that includes migration of partial silicate melts, formation of a shallow magma ocean, and core formation in two distinct stages of metal segregation. In the first stage, a protocore formed at ≈1.5 Ma via settling of metal particles in a mantle magma ocean, followed by metal segregation from a shallow magma ocean at ≈5.4 Ma. As these stages of metal segregation occurred at different times, the two metal fractions had different 182W compositions. Consequently, the final 182W composition of the IVB core does not correspond to a single differentiation event, but represents the average composition of early- and late-segregated core fractions. Our best fit model indicates an ≈100 km radius for the IVB parent body and provides an accretion age of ≈0.1-0.5 Ma after solar system formation. The computed solidification time is, furthermore, consistent with the Re-Os age for crystallization of the IVB core.

Kinetic theory-based numerical modeling and analysis of bi-disperse segregated mixture fluidized bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Konan, N. A.; Huckaby, E. D.

We discuss a series of continuum Euler-Euler simulations of an initially mixed bi-disperse fluidized bed which segregates under certain operating conditions. The simulations use the multi-phase kinetic theory-based description of the momentum and energy exchanges between the phases by Simonin’s Group [see e.g. Gourdel, Simonin and Brunier (1999). Proceedings of 6th International Conference on Circulating Fluidized Beds, Germany, pp. 205-210]. The discussion and analysis of the results focus on the fluid-particle momentum exchange (i.e. drag). Simulations using mono- and poly-disperse fluid-particle drag correlations are analyzed for the Geldart D-type size bi-disperse gas-solid experiments performed by Goldschmidt et al. [Powder Tech.,more » pp. 135-159 (2003)]. The poly-disperse gas-particle drag correlations account for the local particle size distribution by using an effective mixture diameter when calculating the Reynolds number and then correcting the resulting force coefficient. Simulation results show very good predictions of the segregation index for bidisperse beds with the mono-disperse drag correlations contrary to the poly-disperse drag correlations for which the segregation rate is systematically under-predicted. The statistical analysis of the results shows a clear separation in the distribution of the gas-particle mean relaxation times of the small and large particles with simulations using the mono-disperse drag. In contrast, the poly-disperse drag simulations have a significant overlap and also a smaller difference in the mean particle relaxation times. This results in the small and large particles in the bed to respond to the gas similarly without enough relative time lag. The results suggest that the difference in the particle response time induce flow dynamics favorable to a force imbalance which results in the segregation.« less

Kinetic theory-based numerical modeling and analysis of bi-disperse segregated mixture fluidized bed

DOE PAGES

Konan, N. A.; Huckaby, E. D.

2017-06-21

We discuss a series of continuum Euler-Euler simulations of an initially mixed bi-disperse fluidized bed which segregates under certain operating conditions. The simulations use the multi-phase kinetic theory-based description of the momentum and energy exchanges between the phases by Simonin’s Group [see e.g. Gourdel, Simonin and Brunier (1999). Proceedings of 6th International Conference on Circulating Fluidized Beds, Germany, pp. 205-210]. The discussion and analysis of the results focus on the fluid-particle momentum exchange (i.e. drag). Simulations using mono- and poly-disperse fluid-particle drag correlations are analyzed for the Geldart D-type size bi-disperse gas-solid experiments performed by Goldschmidt et al. [Powder Tech.,more » pp. 135-159 (2003)]. The poly-disperse gas-particle drag correlations account for the local particle size distribution by using an effective mixture diameter when calculating the Reynolds number and then correcting the resulting force coefficient. Simulation results show very good predictions of the segregation index for bidisperse beds with the mono-disperse drag correlations contrary to the poly-disperse drag correlations for which the segregation rate is systematically under-predicted. The statistical analysis of the results shows a clear separation in the distribution of the gas-particle mean relaxation times of the small and large particles with simulations using the mono-disperse drag. In contrast, the poly-disperse drag simulations have a significant overlap and also a smaller difference in the mean particle relaxation times. This results in the small and large particles in the bed to respond to the gas similarly without enough relative time lag. The results suggest that the difference in the particle response time induce flow dynamics favorable to a force imbalance which results in the segregation.« less

Professional Guidance: Maternal Negotiation of Primary School Placement for Children Diagnosed with Autism

ERIC Educational Resources Information Center

Lilley, Rozanna

2014-01-01

This article explores the different forms of professional guidance negotiated by mothers as they search for a primary school placement for their child diagnosed with autism. The intensely contested terrain of whether segregated or "regular" classrooms would be "better" for the child shapes the contours of both professional…

Failed Regulations and School Composition: Selective Admission Practices in Chilean Primary Schools

ERIC Educational Resources Information Center

Carrasco, Alejandro; Gutiérrez, Gabriel; Flores, Carolina

2017-01-01

This is an exploratory study about pupil selection. Admission regulations are central to understanding issues of school mix, segregation and educational justice. In Chile, student selection has been intensively discussed but scarcely studied. Using a questionnaire for headteachers (N = 581), we explore how school admission processes are organised…

The Politics of Race and Educational Disparities in Delaware's Public Schools

ERIC Educational Resources Information Center

Davis, Theodore J., Jr.

2017-01-01

Delaware has long played a pivotal role in the nation's struggle to end school segregation and promote educational equality. This article discusses racial disparities in educational achievement and outcomes by examining the state's political history and the politics of race in public education. This article explores educational disparities from a…

A Very "Prudent Integration": White Flight, School Segregation and the Depoliticization of (Anti-)Racism

ERIC Educational Resources Information Center

Araújo, Marta

2016-01-01

This article explores the contemporary legitimation of institutional racism resulting from the prevailing depoliticized framework of integration, which became prominent in the 1960s and is now hegemonic in political and academic debate in Europe. Integration has helped shift the focus to the supposed cultural "inadequacies" of ethnically…

One Room Schools in Iowa.

ERIC Educational Resources Information Center

Ruth, Amy, Ed.

1994-01-01

This issue focuses on one-room school houses in Iowa. At one time, almost 14,000 one-room schools dotted Iowa's rural landscape. Articles explore Native American schools of the past and present, segregation of black students, and Amish schools. An article remembering one-room schools describes the early schools from 1830 to 1858, township schools…

Learning Processes and Social Mobilization in a Swedish Metropolitan Hip-Hop Collective

ERIC Educational Resources Information Center

Beach, Dennis; Sernhede, Ove

2012-01-01

Based on ethnographic research on the encounter between local culture and schools in multicultural suburban areas, this article explores possibilities suggested by autonomous learning activities in a hip-hop collective that may have a potential to break urban segregation patterns. The collective's artistic production raises questions that have not…

The Institutional and the Personal in Explaining Cognitive Outcomes under Desegregation: A Mississippi Test.

ERIC Educational Resources Information Center

Wirt, Frederick M.

This paper explores the comparative utility of institutional and personal qualities in explaining cognitive outcomes in self-esteem, racial attitudes, and political and social involvement in the context of desegregated schools. Three kinds of schools in a Mississippi county were studied: public desegregated, public segregated black, and private…

Pictorial Essay: Exploring Strategies to Develop More Inclusive Approaches to Actor-Training

ERIC Educational Resources Information Center

Aita, Sean

2012-01-01

In 1975 a new definition of disability, challenging the conventional medical model, was proposed by the Union of the Physically Impaired Against Segregation (UPIAS) and the Disability Alliance. Subsequently extended to cover all impairments, this definition considers disability to be the "disadvantage or restriction caused by a contemporary…

Examining the Cross-Roads: School Segregation in Indiana

ERIC Educational Resources Information Center

Moon, Jodi S.; Krull, Lauren

2017-01-01

Demographics in the U.S. have changed dramatically over the last three decades. Indiana's demographics are changing, too--albeit less dramatically. To explore how demographic shifts are changing the composition of Indiana's schools, the Center for Evaluation and Education Policy (CEEP) uses Common Core of Data (CCD) school enrollment data from the…

Labor Market Experiences of Central American Migrants in Washington, D.C.

ERIC Educational Resources Information Center

Repak, Terry A.

1993-01-01

Explores labor market experiences of Central American men and women in Washington, DC; analyzes variables determining wage levels; and assesses employment mobility. Results from 50 individuals and 100 households illustrate striking advantages in income and mobility of men. Most migrant women in Washington, DC, are segregated into low-paid service…

Expanding METCO and Closing Achievement Gaps. White Paper No. 129

ERIC Educational Resources Information Center

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…

Solidifying Segregation or Promoting Diversity? School Closure and Rezoning in an Urban District

ERIC Educational Resources Information Center

Siegel-Hawley, Genevieve; Bridges, Kimberly; Shields, Thomas J.

2017-01-01

Purpose: Layered with myriad considerations, school closure and rezoning processes in urban school systems are politically fraught with the potential for damaging consequences. This article explores the politics and impacts of a closure and rezoning process in Richmond, Virginia, through the lens of themes applicable to urban school systems and…

Auditory Stream Segregation and the Perception of Across-Frequency Synchrony

ERIC Educational Resources Information Center

Micheyl, Christophe; Hunter, Cynthia; Oxenham, Andrew J.

2010-01-01

This study explored the extent to which sequential auditory grouping affects the perception of temporal synchrony. In Experiment 1, listeners discriminated between 2 pairs of asynchronous "target" tones at different frequencies, A and B, in which the B tone either led or lagged. Thresholds were markedly higher when the target tones were temporally…

Contesting Ideologies and the Struggle for Equality: Reconsidering the Politics of Education in South Africa

ERIC Educational Resources Information Center

Tomlin, Hannah

2016-01-01

As international standards are continually publicized, countries across the globe have adapted educational policies to meet the demands of the global market, which has led to much emphasis on specific subjects and teaching methods. Although modern educational policies tend to focus on rhetoric about inclusion, systematic segregation remains in…

25 CFR 542.7 - What are the minimum internal control standards for bingo?

Code of Federal Regulations, 2010 CFR

2010-04-01

... acceptable. (b) Game play standards. (1) The functions of seller and payout verifier shall be segregated... selected in the bingo game. (5) Each ball shall be shown to a camera immediately before it is called so that it is individually displayed to all customers. For speed bingo games not verified by camera...

25 CFR 542.7 - What are the minimum internal control standards for bingo?

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Game play standards. (1) The functions of seller and payout verifier shall be segregated. Employees who... selected in the bingo game. (5) Each ball shall be shown to a camera immediately before it is called so that it is individually displayed to all customers. For speed bingo games not verified by camera...

International Representations of Inclusive Education: How Is Inclusive Practice Reflected in the Professional Teaching Standards of China and Australia?

ERIC Educational Resources Information Center

Carrington, Suzanne; Saggers, Beth; Adie, Lenore; Zhu, Nan; Gu, Dingqian; Hu, Xiaoyi; Wang, Yan; Deng, Meng; Mu, Guanglun Michael

2015-01-01

Inclusive education focuses on addressing marginalisation, segregation and exclusion within policy and practice. The purpose of this article is to use critical discourse analysis to examine how inclusion is represented in the education policy and professional documents of two countries, Australia and China. In particular, teacher professional…

A Decade of Change in Mainstream Education for Children with Intellectual Disabilities in the Republic of Ireland

ERIC Educational Resources Information Center

McConkey, Roy; Kelly, Caraoisa; Craig, Sarah; Shevlin, Michael

2016-01-01

Inclusive rather than segregated schooling has been advocated in several significant international declarations during the past two decades. Even so children with significant intellectual disabilities are at greater risk of being excluded from mainstream education, unless particular efforts are made to support them in such settings. These children…

"Unconscious" Inclusion of Students with Learning Disabilities in a Malaysian Mainstream Primary School: Teachers' Perspectives

ERIC Educational Resources Information Center

Lee, Lay Wah; Low, Hui Min

2013-01-01

The inclusion of children with special needs in mainstream regular schools has been seen as the best practice in special education provision, most markedly since the 90s. International research has provided amassing evidence towards the advantages of inclusive model over a segregation model of special education provision. However, nearly two…

Lexical decision as an endophenotype for reading comprehension: An exploration of an association

PubMed Central

NAPLES, ADAM; KATZ, LEN; GRIGORENKO, ELENA L.

2012-01-01

Based on numerous suggestions in the literature, we evaluated lexical decision (LD) as a putative endophenotype for reading comprehension by investigating heritability estimates and segregation analyses parameter estimates for both of these phenotypes. Specifically, in a segregation analysis of a large sample of families, we established that there is little to no overlap between genes contributing to LD and reading comprehension and that the genetic mechanism behind LD derived from this analysis appears to be more complex than that for reading comprehension. We conclude that in our sample, LD is not a good candidate as an endophenotype for reading comprehension, despite previous suggestions from the literature. Based on this conclusion, we discuss the role and benefit of the endophenotype approach in studies of complex human cognitive functions. PMID:23062302

Seven Years Later: Effects of a Neighborhood Mobility Program on Poor Black and Latino Adults' Well-Being

ERIC Educational Resources Information Center

Fauth, Rebecca C.; Leventhal, Tama; Brooks-Gunn, Jeanne

2008-01-01

This study explored program effects on adults' well-being seven years following the implementation of a court-ordered neighborhood mobility program. Low-income black and Latino adults residing in poor, segregated neighborhoods in Yonkers, New York were randomly selected to relocate to publicly funded town-houses in middle-class neighborhoods…

The Discovery of Feeblemindedness among Immigrant Children through Intelligence Tests in California in the 1910S

ERIC Educational Resources Information Center

Omori, Mariko

2018-01-01

This paper explores the way in which psychologists classified immigrant children as feebleminded through the use of intelligence testing and how state organisations consequently segregated them from public schools based on the scientific evidence. First, I show the way in which the psychologist Lewis Terman utilised intelligence testing to…

Erasing Differences for the Sake of Inclusion: How Mexican/Mexican American Students Construct Historical Narratives

ERIC Educational Resources Information Center

Santiago, Maribel

2017-01-01

"Mendez v. Westminster," a case about 1940s Mexican American school segregation, is a new vehicle for including Mexican Americans into U.S. history classrooms. This study explores how a class of primarily Mexican American students, who because of their heritage might develop a personal connection to the case, made sense of…

Exploring the Factors Prompting British Columbia's First Integration Initiative: The Case of Port Essington Indian Day School

ERIC Educational Resources Information Center

Raptis, Helen

2011-01-01

Little empirical research has investigated the integration of Canada's Aboriginal children into provincial school systems. Furthermore, the limited existing research has tended to focus on policymakers and government officials at the national level. Thus, the policy shift from segregation to integration has generally been attributed to Canada's…

Schools, Choice and Reputation: Local School Markets and the Distribution of Symbolic Capital in Segregated Cities

ERIC Educational Resources Information Center

Bunar, Nihad; Ambrose, Anna

2016-01-01

An exploration is presented of how urban spaces, polarized by class and ethnicity, structure the basic conditions of emerging local school markets. The authors investigate how the distribution of symbolic capital, or "hot knowledge" of the market, affects schools, the market, and the urban spaces themselves. The study is guided by…

Housing Mix, School Mix: Barriers to Success

ERIC Educational Resources Information Center

Camina, M. M.; Iannone, P.

2014-01-01

Recent UK policy has emphasised both the development of socially mixed communities and the creation of balanced school intakes. In this paper, we use a case study of an area of mixed tenure in eastern England to explore policy in practice and the extent to which mechanisms of segregation impact on both the creation of socially mixed neighbourhoods…

The Perspectives of Singapore Secondary School Students with Vision Impairments towards Their Inclusion in Mainstream Education

ERIC Educational Resources Information Center

West, John; Houghton, Stephen; Taylor, Myra; Ling, Phua Kia

2004-01-01

Students with vision impairments in Singapore are educated in segregated settings from an early age. On completing primary school these students continue their education in mainstream secondary school settings. This transition requires considerable adjustment on the part of students with vision impairments. The present research explored the social…

The Relationship between Residential Land Use Patterns and the Educational Outcomes of Economically Disadvantaged Students in Texas

ERIC Educational Resources Information Center

Van Zandt, Shannon; Wunneburger, Douglas F.

2011-01-01

Disparate outcomes resulting from economic segregation in public primary schools have been the subject of much debate and litigation. Little research, however, examines whether negative outcomes may be exacerbated by inequities in the distribution of housing across metropolitan areas. This article explores connections between residential land use…

School Segregation and Its Effects on Educational Equality and Efficiency in 16 OECD Comprehensive School Systems

ERIC Educational Resources Information Center

Benito, Ricard; Alegre, Miquel Àngel; Gonzàlez-Balletbò, Isaac

2014-01-01

Using PISA data for 16 Western OECD countries having comprehensive school systems, we explore the conditions under which the socioeconomic composition of schools affects educational efficiency and equality, to a greater or lesser extent. First, a multilevel analysis is applied to examine and compare the effect of school socioeconomic composition…

"It Should Be Better All Together": Exploring Strategies for "Undoing" Gender in Coeducational Physical Education

ERIC Educational Resources Information Center

Hills, Laura A.; Croston, Amanda

2012-01-01

Physical education (PE) remains the subject in coeducational schools that is most likely to be delivered in gender segregated sessions. Decisions to offer single sex lessons are often underpinned by discourses and practices associated with doing gender that emphasise differences in boys' and girls' attitudes, behaviours, abilities and experiences.…

On reliable time-frequency characterization and delay estimation of stimulus frequency otoacoustic emissions

NASA Astrophysics Data System (ADS)

Biswal, Milan; Mishra, Srikanta

2018-05-01

The limited information on origin and nature of stimulus frequency otoacoustic emissions (SFOAEs) necessitates a thorough reexamination into SFOAE analysis procedures. This will lead to a better understanding of the generation of SFOAEs. The SFOAE response waveform in the time domain can be interpreted as a summation of amplitude modulated and frequency modulated component waveforms. The efficiency of a technique to segregate these components is critical to describe the nature of SFOAEs. Recent advancements in robust time-frequency analysis algorithms have staked claims on the more accurate extraction of these components, from composite signals buried in noise. However, their potential has not been fully explored for SFOAEs analysis. Indifference to distinct information, due to nature of these analysis techniques, may impact the scientific conclusions. This paper attempts to bridge this gap in literature by evaluating the performance of three linear time-frequency analysis algorithms: short-time Fourier transform (STFT), continuous Wavelet transform (CWT), S-transform (ST) and two nonlinear algorithms: Hilbert-Huang Transform (HHT), synchrosqueezed Wavelet transform (SWT). We revisit the extraction of constituent components and estimation of their magnitude and delay, by carefully evaluating the impact of variation in analysis parameters. The performance of HHT and SWT from the perspective of time-frequency filtering and delay estimation were found to be relatively less efficient for analyzing SFOAEs. The intrinsic mode functions of HHT does not completely characterize the reflection components and hence IMF based filtering alone, is not recommended for segregating principal emission from multiple reflection components. We found STFT, WT, and ST to be suitable for canceling multiple internal reflection components with marginal altering in SFOAE.

Investigating niche partitioning of ectomycorrhizal fungi in specialized rooting zones of the monodominant leguminous tree Dicymbe corymbosa.

PubMed

Smith, Matthew E; Henkel, Terry W; Williams, Gwendolyn C; Aime, M Catherine; Fremier, Alexander K; Vilgalys, Rytas

2017-07-01

Temperate ectomycorrhizal (ECM) fungi show segregation whereby some species dominate in organic layers and others favor mineral soils. Weak layering in tropical soils is hypothesized to decrease niche space and therefore reduce the diversity of ectomycorrhizal fungi. The Neotropical ECM tree Dicymbe corymbosa forms monodominant stands and has a distinct physiognomy with vertical crown development, adventitious roots and massive root mounds, leading to multi-stemmed trees with spatially segregated rooting environments: aerial litter caches, aerial decayed wood, organic root mounds and mineral soil. We hypothesized that these microhabitats host distinct fungal assemblages and therefore promote diversity. To test our hypothesis, we sampled D. corymbosa ectomycorrhizal root tips from the four microhabitats and analyzed community composition based on pyrosequencing of fungal internal transcribed spacer (ITS) barcode markers. Several dominant fungi were ubiquitous but analyses nonetheless suggested that communities in mineral soil samples were statistically distinct from communities in organic microhabitats. These data indicate that distinctive rooting zones of D. corymbosa contribute to spatial segregation of the fungal community and likely enhance fungal diversity. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

A new principle of figure-ground segregation: The accentuation.

PubMed

Pinna, Baingio; Reeves, Adam; Koenderink, Jan; van Doorn, Andrea; Deiana, Katia

2018-02-01

The problem of perceptual organization was studied by Gestalt psychologists in terms of figure-ground segregation. In this paper we explore a new principle of figure-ground segregation: accentuation. We demonstrate the effectiveness of accentuation relative to other Gestalt principles, and also consider it autonomous as it can agree with or oppose them. We consider three dynamic aspects of the principle, namely: attraction, accentuation and assignment. Each creature needs to attract, fascinate, seduce, draw attention (e.g., a mate or a prey animal) or distract, refuse, dissuade, discourage, repulse (e.g., a predator). Similarly, each organism needs to accentuate, highlight, stress, underline, emphasize or distract from another. Thus, accentuation assigns meaning to a visual pattern such as a coat, a plumage or a flower. False eyes (ocelli) and dots (diematic patterns) demonstrate "deceiving camouflage by accentuation" that confuses predators/preys and hides or highlights vital body parts (butterflies/flowers). They also display the deceiving appearance and exhibition of biological fitness. The same accents may serve different or even opposite goals. We conclude that accentuation improves the adaptive fitness of organisms in multifarious ways. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reduced integration and improved segregation of functional brain networks in Alzheimer’s disease

NASA Astrophysics Data System (ADS)

Kabbara, A.; Eid, H.; El Falou, W.; Khalil, M.; Wendling, F.; Hassan, M.

2018-04-01

Objective. Emerging evidence shows that cognitive deficits in Alzheimer’s disease (AD) are associated with disruptions in brain functional connectivity. Thus, the identification of alterations in AD functional networks has become a topic of increasing interest. However, to what extent AD induces disruption of the balance of local and global information processing in the human brain remains elusive. The main objective of this study is to explore the dynamic topological changes of AD networks in terms of brain network segregation and integration. Approach. We used electroencephalography (EEG) data recorded from 20 participants (10 AD patients and 10 healthy controls) during resting state. Functional brain networks were reconstructed using EEG source connectivity computed in different frequency bands. Graph theoretical analyses were performed assess differences between both groups. Main results. Results revealed that AD networks, compared to networks of age-matched healthy controls, are characterized by lower global information processing (integration) and higher local information processing (segregation). Results showed also significant correlation between the alterations in the AD patients’ functional brain networks and their cognitive scores. Significance. These findings may contribute to the development of EEG network-based test that could strengthen results obtained from currently-used neurophysiological tests in neurodegenerative diseases.

Reduced integration and improved segregation of functional brain networks in Alzheimer's disease.

PubMed

Kabbara, A; Eid, H; El Falou, W; Khalil, M; Wendling, F; Hassan, M

2018-04-01

Emerging evidence shows that cognitive deficits in Alzheimer's disease (AD) are associated with disruptions in brain functional connectivity. Thus, the identification of alterations in AD functional networks has become a topic of increasing interest. However, to what extent AD induces disruption of the balance of local and global information processing in the human brain remains elusive. The main objective of this study is to explore the dynamic topological changes of AD networks in terms of brain network segregation and integration. We used electroencephalography (EEG) data recorded from 20 participants (10 AD patients and 10 healthy controls) during resting state. Functional brain networks were reconstructed using EEG source connectivity computed in different frequency bands. Graph theoretical analyses were performed assess differences between both groups. Results revealed that AD networks, compared to networks of age-matched healthy controls, are characterized by lower global information processing (integration) and higher local information processing (segregation). Results showed also significant correlation between the alterations in the AD patients' functional brain networks and their cognitive scores. These findings may contribute to the development of EEG network-based test that could strengthen results obtained from currently-used neurophysiological tests in neurodegenerative diseases.

Architecture of the ParF*ParG protein complex involved in prokaryotic DNA segregation.

PubMed

Barillà, Daniela; Hayes, Finbarr

2003-07-01

The mechanism by which low copy number plasmids are segregated at cell division involves the concerted action of two plasmid-encoded proteins that assemble on a centromere-like site. This study explores the topology of the DNA segregation machinery specified by the parFG locus of TP228, a partition system which is phylogenetically distinct from more well-characterized archetypes. A variety of genetic, biochemical and biophysical strategies revealed that the ParG protein is dimeric. ParF, which is more closely related to the cell division regulator MinD than to the prototypical ParA partition protein of plasmid P1, is instead multimeric and its polymeric state appears to be modulated by ATP which correlates with the proposed ATP-binding activity of ParF. ParG interacts in a sequence-specific manner with the DNA region upstream of the parFG locus and this binding is modulated by ParF. Intriguingly, the ParF and ParG proteins form at least two types of discrete complex in the absence of this region suggesting that the assembly dynamics of these proteins onto DNA is intricate.

Patterns of Racial Diversity and Segregation in the United States: 1990–2010*

PubMed Central

Wright, Richard; Ellis, Mark; Holloway, Steven R.; Wong, Sandy

2014-01-01

The growing ethnic and racial diversity of the United States is evident at all spatial scales. One of the striking features of this new mixture of peoples, however, is that this new diversity often occurs in tandem with racial concentration. This article surveys these new geographies from four points of view: the nation as a whole, states, large metropolitan areas, and neighborhoods. The analysis at each scale relies on a new taxonomy of racial composition that simultaneously appraises both diversity and the lack thereof (Holloway, Wright, and Ellis 2012). Urban analysis often posits neighborhood racial segregation and diversity as either endpoints on a continuum of racial dominance or mirror images of one another. We disturb that perspective and stress that segregation and diversity must be jointly understood—they are necessarily related, although not as inevitable binary opposites. Using census data from 1990, 2000, and 2010, the research points to how patterns of racial diversity and dominance interact across varying spatial scales. This investigation helps answer some basic questions about the changing geographies of racialized groups, setting the stage for the following articles that explore the relationship between geography and the participation of underrepresented groups in higher education. PMID:25083001

Residential segregation, geographic proximity and type of services used: Evidence for racial/ethnic disparities in mental health

PubMed Central

Dinwiddie, Gniesha Y.; Gaskin, Darrell J.; Chan, Kitty S.; Norrington, Janette; McCleary, Rachel

2014-01-01

Residential characteristics influence opportunities, life chances and access to health services in the United States but what role does residential segregation play in differential access and mental health service utilization? We explore this issue using secondary data from the 2006 Medical Expenditure Panel Survey, 2006 American Medical Association Area Research File and the 2000 Census. Our sample included 9737 whites, 3362 African Americans and 5053 Latinos living in Metropolitan Statistical Areas. Using logistic regression techniques, results show respondents high on Latino isolation and Latino centralization resided in psychiatrist shortage areas whereas respondents high on African American concentration had access to psychiatrists in their neighborhoods. Predominant race of neighborhood was associated with the type of mental health professional used where respondents in majority African American neighborhoods were treated by non-psychiatrists and general doctors whereas respondents in majority Latino neighborhoods saw general doctors. Respondents high on Latino Isolation and Latino Centralization were more likely to utilize non-psychiatrists. These findings suggest that living in segregated neighborhoods influence access and utilization of mental health services differently for race/ethnic groups which contradicts findings that suggest living in ethnic enclaves is beneficial to health. PMID:23312305

Discovering non-random segregation of sister chromatids: the naïve treatment of a premature discovery

PubMed Central

Lark, Karl G.

2013-01-01

The discovery of non-random chromosome segregation (Figure 1) is discussed from the perspective of what was known in 1965 and 1966. The distinction between daughter, parent, or grandparent strands of DNA was developed in a bacterial system and led to the discovery that multiple copies of DNA elements of bacteria are not distributed randomly with respect to the age of the template strand. Experiments with higher eukaryotic cells demonstrated that during mitosis Mendel’s laws were violated; and the initial serendipitous choice of eukaryotic cell system led to the striking example of non-random segregation of parent and grandparent DNA template strands in primary cultures of cells derived from mouse embryos. Attempts to extrapolate these findings to established tissue culture lines demonstrated that the property could be lost. Experiments using plant root tips demonstrated that the phenomenon exists in plants and that it was, at some level, under genetic control. Despite publication in major journals and symposia (Lark et al., 1966, 1967; Lark, 1967, 1969a,b,c) the potential implications of these findings were ignored for several decades. Here we explore possible reasons for the pre-maturity (Stent, 1972) of this discovery. PMID:23378946

The Stanford Data Miner: a novel approach for integrating and exploring heterogeneous immunological data.

PubMed

Siebert, Janet C; Munsil, Wes; Rosenberg-Hasson, Yael; Davis, Mark M; Maecker, Holden T

2012-03-28

Systems-level approaches are increasingly common in both murine and human translational studies. These approaches employ multiple high information content assays. As a result, there is a need for tools to integrate heterogeneous types of laboratory and clinical/demographic data, and to allow the exploration of that data by aggregating and/or segregating results based on particular variables (e.g., mean cytokine levels by age and gender). Here we describe the application of standard data warehousing tools to create a novel environment for user-driven upload, integration, and exploration of heterogeneous data. The system presented here currently supports flow cytometry and immunoassays performed in the Stanford Human Immune Monitoring Center, but could be applied more generally. Users upload assay results contained in platform-specific spreadsheets of a defined format, and clinical and demographic data in spreadsheets of flexible format. Users then map sample IDs to connect the assay results with the metadata. An OLAP (on-line analytical processing) data exploration interface allows filtering and display of various dimensions (e.g., Luminex analytes in rows, treatment group in columns, filtered on a particular study). Statistics such as mean, median, and N can be displayed. The views can be expanded or contracted to aggregate or segregate data at various levels. Individual-level data is accessible with a single click. The result is a user-driven system that permits data integration and exploration in a variety of settings. We show how the system can be used to find gender-specific differences in serum cytokine levels, and compare them across experiments and assay types. We have used the tools and techniques of data warehousing, including open-source business intelligence software, to support investigator-driven data integration and mining of diverse immunological data.

The Stanford Data Miner: a novel approach for integrating and exploring heterogeneous immunological data

PubMed Central

2012-01-01

Background Systems-level approaches are increasingly common in both murine and human translational studies. These approaches employ multiple high information content assays. As a result, there is a need for tools to integrate heterogeneous types of laboratory and clinical/demographic data, and to allow the exploration of that data by aggregating and/or segregating results based on particular variables (e.g., mean cytokine levels by age and gender). Methods Here we describe the application of standard data warehousing tools to create a novel environment for user-driven upload, integration, and exploration of heterogeneous data. The system presented here currently supports flow cytometry and immunoassays performed in the Stanford Human Immune Monitoring Center, but could be applied more generally. Results Users upload assay results contained in platform-specific spreadsheets of a defined format, and clinical and demographic data in spreadsheets of flexible format. Users then map sample IDs to connect the assay results with the metadata. An OLAP (on-line analytical processing) data exploration interface allows filtering and display of various dimensions (e.g., Luminex analytes in rows, treatment group in columns, filtered on a particular study). Statistics such as mean, median, and N can be displayed. The views can be expanded or contracted to aggregate or segregate data at various levels. Individual-level data is accessible with a single click. The result is a user-driven system that permits data integration and exploration in a variety of settings. We show how the system can be used to find gender-specific differences in serum cytokine levels, and compare them across experiments and assay types. Conclusions We have used the tools and techniques of data warehousing, including open-source business intelligence software, to support investigator-driven data integration and mining of diverse immunological data. PMID:22452993

Neural alpha oscillations index the balance between self-other integration and segregation in real-time joint action.

PubMed

Novembre, Giacomo; Sammler, Daniela; Keller, Peter E

2016-08-01

Shared knowledge and interpersonal coordination are prerequisites for most forms of social behavior. Influential approaches to joint action have conceptualized these capacities in relation to the separate constructs of co-representation (knowledge) and self-other entrainment (coordination). Here we investigated how brain mechanisms involved in co-representation and entrainment interact to support joint action. To do so, we used a musical joint action paradigm to show that the neural mechanisms underlying co-representation and self-other entrainment are linked via a process - indexed by EEG alpha oscillations - regulating the balance between self-other integration and segregation in real time. Pairs of pianists performed short musical items while action familiarity and interpersonal (behavioral) synchronization accuracy were manipulated in a factorial design. Action familiarity referred to whether or not pianists had rehearsed the musical material performed by the other beforehand. Interpersonal synchronization was manipulated via congruent or incongruent tempo change instructions that biased performance timing towards the impending, new tempo. It was observed that, when pianists were familiar with each other's parts, millisecond variations in interpersonal synchronized behavior were associated with a modulation of alpha power over right centro-parietal scalp regions. Specifically, high behavioral entrainment was associated with self-other integration, as indexed by alpha suppression. Conversely, low behavioral entrainment encouraged reliance on internal knowledge and thus led to self-other segregation, indexed by alpha enhancement. These findings suggest that alpha oscillations index the processing of information about self and other depending on the compatibility of internal knowledge and external (environmental) events at finely resolved timescales. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Role of the School Psychologist in Inclusive Education for Ensuring Quality Learning Outcomes for All Learners

ERIC Educational Resources Information Center

Forlin, Chris

2010-01-01

In comparison to international perspectives, the specific role of the school psychologist in Hong Kong will provide a case study of the tensions experienced by a system in transition between a very traditional, highly segregated education system, to one that is actively promoting a whole school approach to inclusion. Consideration will initially…

Income inequality and income segregation.

PubMed

Reardon, Sean F; Bischoff, Kendra

2011-01-01

This article investigates how the growth in income inequality from 1970 to 2000 affected patterns of income segregation along three dimensions: the spatial segregation of poverty and affluence, race-specific patterns of income segregation, and the geographic scale of income segregation. The evidence reveals a robust relationship between income inequality and income segregation, an effect that is larger for black families than for white families. In addition, income inequality affects income segregation primarily through its effect on the large-scale spatial segregation of affluence rather than by affecting the spatial segregation of poverty or by altering small-scale patterns of income segregation.

Framing effects in choices between multioutcome life-expectancy lotteries.

PubMed

Bernstein, L M; Chapman, G B; Elstein, A S

1999-01-01

To explore framing or editing effects and a method to debias framing in a clinical context. Clinical scenarios using multioutcome life-expectancy lotteries of equal value required choices between two supplementary drugs that either prolonged or shortened life from the 20-year beneficial effect of a baseline drug. The effects of these supplementary drugs were presented in two conditions, using a between-subjects design. In segregated editing (n = 116) the effects were presented separately from the effects of the baseline drug. In integrated editing (n = 100), effects of supplementary and baseline drugs were combined in the lottery presentation. Each subject responded to 30 problems. To explore one method of debiasing, another 100 subjects made choices after viewing both segregated and integrated editings of 20 problems (dual framing). Statistically significant preference reversals between segregated and integrated editing of pure lotteries occurred only when one framing placed outcomes in the gain domain, and the other framing placed them in the loss domain. When both editings resulted in gain-domain outcomes only, there was no framing effect. There was a related relationship of framing-effect shifts from losses to gains in mixed-lottery-choice problems. Responses to the dual framing condition did not consistently coincide with responses to either single framing. In some situations, dual framing eliminated or lessened framing effects. The results support two components of prospect theory, coding outcomes as gains or losses from a reference point, and an s-shaped utility function (concave in gain, convex in loss domains). Presenting both alternative editings of a complex situation prior to choice more fully informs the decision maker and may help to reduce framing effects. Given the extent to which preferences shift in response to alternative presentations, it is unclear which choice represents the subject's "true preferences."

Molecular dynamics simulation: a tool for exploration and discovery using simple models

NASA Astrophysics Data System (ADS)

Rapaport, D. C.

2014-12-01

Emergent phenomena share the fascinating property of not being obvious consequences of the design of the system in which they appear. This characteristic is no less relevant when attempting to simulate such phenomena, given that the outcome is not always a foregone conclusion. The present survey focuses on several simple model systems that exhibit surprisingly rich emergent behavior, all studied by molecular dynamics (MD) simulation. The examples are taken from the disparate fields of fluid dynamics, granular matter and supramolecular self-assembly. In studies of fluids modeled at the detailed microscopic level using discrete particles, the simulations demonstrate that complex hydrodynamic phenomena in rotating and convecting fluids—the Taylor-Couette and Rayleigh-Bénard instabilities—can not only be observed within the limited length and time scales accessible to MD, but even allow quantitative agreement to be achieved. Simulation of highly counter-intuitive segregation phenomena in granular mixtures, again using MD methods, but now augmented by forces producing damping and friction, leads to results that resemble experimentally observed axial and radial segregation in the case of a rotating cylinder and to a novel form of horizontal segregation in a vertically vibrated layer. Finally, when modeling self-assembly processes analogous to the formation of the polyhedral shells that package spherical viruses, simulation of suitably shaped particles reveals the ability to produce complete, error-free assembly and leads to the important general observation that reversible growth steps contribute to the high yield. While there are limitations to the MD approach, both computational and conceptual, the results offer a tantalizing hint of the kinds of phenomena that can be explored and what might be discovered when sufficient resources are brought to bear on a problem.

iTAG Barley: A 9-12 classroom module to explore gene expression and segregation using Oregon Wolfe Barley

USDA-ARS?s Scientific Manuscript database

The Oregon Wolfe Barleys (OWBs) are a model resource for genetics research and instruction (http://barleyworld.org/oregonwolfe ; http://wheat.pw.usda.gov/ggpages/OWB_gallery/ISS-OWB/index.htm). The population of 94 doubled haploid lines was developed from an F1 of a cross between dominant and reces...

Exploring the Landscape of Inclusion: Profiles of Inclusive versus Segregated School Districts in the United States

ERIC Educational Resources Information Center

Marks, Susan Unok; Kurth, Jennifer A.; Bartz, Jody Marie

2014-01-01

Although inclusive education has been increasing in frequency for students with disabilities in the United States, for many students, the opportunity to be educated with their peers without disabilities continues to be out of reach despite decades of efforts by those promoting the vision of inclusion. This exploratory case study used interviews…

Caught in the Conundrum: Neoliberalism and Education in Post-Conflict Northern Ireland--Exploring Shared Education

ERIC Educational Resources Information Center

Hughes, Joanne; Donnelly, Caitlin; Leitch, Ruth; Burns, Stephanie

2016-01-01

Northern Ireland (NI) is emerging from a violent period in its troubled history and remains a society characterized by segregation between its two main communities. Nowhere is this more apparent than in education, where for the most part Catholic and Protestant pupils are educated separately. During the last 30 years there has been twofold…

Segregation Versus Inclusion: Understanding Minority Serving Higher Education Institutions in the U.S. and Canada

ERIC Educational Resources Information Center

Di Virgilio, Alessia

2013-01-01

This article explores the issues surrounding the establishment of an Africentric public school in Ontario. It provides a historical overview of the foundation of historically Black colleges and universities (HBCUs) in the U.S. as well as the benefits they provide to Black students, communities and the labor force. It extrapolates the tropes…

Comparable Worth: Is It Anything More Than "The Latest" Discrimination Issue?

ERIC Educational Resources Information Center

Lewis, John F.

The comparable worth issue has become heated in the 1980s and is especially important to minorities and women. The debate, explored in this eighth chapter of a book on school law, concerns the causes of and cures for the earning gap between employed men and women. One major cause of the gap is occupational segregation. Comparable worth advocates…

Analysis of recombination QTLs, segregation distortion, and epistasis for fitness in maize multiple populations using ultra-high-density markers

USDA-ARS?s Scientific Manuscript database

Understanding the maize genomic features would be useful for the study of genetic diversity and evolution and for maize breeding. Here, we used two maize nested association mapping (NAM) populations separately derived in China (CN-NAM) and the US (US-NAM) to explore the maize genomic features. The t...

Educational Leadership in Our Peculiar Institutions: Understandings of Principals in Segregated, White-Staffed Urban Elementary Schools in the United States

ERIC Educational Resources Information Center

Milligan, Tonya; Howley, Craig

2015-01-01

This study explores how 10 principals in mostly-Black U.S. urban elementary schools staffed by mostly-White faculty understood and experienced the manifestations of racial differences. Narrative inquiry with nearly 700 pages of transcript data yielded three themes: (1) gradients of color-conscious leadership, (2) principals as moral agents, and…

Intergenerational Transmission of Gender Segregation: How Parents' Occupational Field Affects Gender Differences in Field of Study Choices

ERIC Educational Resources Information Center

Vleuten, Maaike; Jaspers, Eva; Maas, Ineke; van der Lippe, Tanja

2018-01-01

The study explores how parents' occupational field affects gender differences in educational fields. On the one hand, the theory of direct transfer predicts that adolescents enter fields similar to those of their parents because of intergenerational transmission of occupation-specific resources and that adolescents are more likely to draw upon the…

Transient dynamics of vulcanian explosions and column collapse.

PubMed

Clarke, A B; Voight, B; Neri, A; Macedonio, G

2002-02-21

Several analytical and numerical eruption models have provided insight into volcanic eruption behaviour, but most address plinian-type eruptions where vent conditions are quasi-steady. Only a few studies have explored the physics of short-duration vulcanian explosions with unsteady vent conditions and blast events. Here we present a technique that links unsteady vent flux of vulcanian explosions to the resulting dispersal of volcanic ejecta, using a numerical, axisymmetric model with multiple particle sizes. We use observational data from well documented explosions in 1997 at the Soufrière Hills volcano in Montserrat, West Indies, to constrain pre-eruptive subsurface initial conditions and to compare with our simulation results. The resulting simulations duplicate many features of the observed explosions, showing transitional behaviour where mass is divided between a buoyant plume and hazardous radial pyroclastic currents fed by a collapsing fountain. We find that leakage of volcanic gas from the conduit through surrounding rocks over a short period (of the order of 10 hours) or retarded exsolution can dictate the style of explosion. Our simulations also reveal the internal plume dynamics and particle-size segregation mechanisms that may occur in such eruptions.

Conjunction search revisited.

PubMed

Treisman, A; Sato, S

1990-08-01

Search for conjunctions of highly discriminable features can be rapid or even parallel. This article explores three possible accounts based on (a) perceptual segregation, (b) conjunction detectors, and (c) inhibition controlled separately by two or more distractor features. Search rates for conjunctions of color, size, orientation, and direction of motion correlated closely with an independent measure of perceptual segregation. However, they appeared unrelated to the physiology of single-unit responses. Each dimension contributed additively to conjunction search rates, suggesting that each was checked independently of the others. Unknown targets appear to be found only by serial search for each in turn. Searching through 4 sets of distractors was slower than searching through 2. The results suggest a modification of feature integration theory, in which attention is controlled not only by a unitary "window" but also by a form of feature-based inhibition.

Ethanol-nicotine interactions in long-sleep and short-sleep mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Fiebre, C.M.; Marks, M.J.; Collins, A.C.

The possibility that common genetic factors regulate initial sensitivities to ethanol and nicotine as well as the development of cross-tolerance between these agents was explored using the long-sleep (LS) and short-sleep (SS) mice. The LS mice proved to be more sensitive to an acute challenge with nicotine than were the SS mice. Segregation analysis (F1, F2, backcross) indicated that ethanol sensitivity and nicotine sensitivity segregate together. Acute pretreatment with nicotine did not significantly affect sensitivity to ethanol, but ethanol pretreatment altered nicotine responsiveness. The LS mice develop more tolerance to nicotine and ethanol than do the SS and they alsomore » develop more cross-tolerance. These genetically determined differences in initial sensitivities, and tolerance and cross-tolerance development are not readily explained by differences in brain nicotinic receptor numbers.« less

Nanoscale decomposition of Nb-Ru-O

NASA Astrophysics Data System (ADS)

Music, Denis; Geyer, Richard W.; Chen, Yen-Ting

2016-11-01

A correlative theoretical and experimental methodology has been employed to explore the decomposition of amorphous Nb-Ru-O at elevated temperatures. Density functional theory based molecular dynamics simulations reveal that amorphous Nb-Ru-O is structurally modified within 10 ps at 800 K giving rise to an increase in the planar metal - oxygen and metal - metal population and hence formation of large clusters, which signifies atomic segregation. The driving force for this atomic segregation process is 0.5 eV/atom. This is validated by diffraction experiments and transmission electron microscopy of sputter-synthesized Nb-Ru-O thin films. Room temperature samples are amorphous, while at 800 K nanoscale rutile RuO2 grains, self-organized in an amorphous Nb-O matrix, are observed, which is consistent with our theoretical predictions. This amorphous/crystalline interplay may be of importance for next generation of thermoelectric devices.

Medical educators working abroad: a pilot study of educators' experiences in the Middle East.

PubMed

McLean, Michelle; McKimm, Judy; Major, Stella

2014-09-01

Medical education is now a global enterprise, with many medical educators working internationally, either for short or longer periods or even permanently. In parallel, many medical schools are now involved in collaborations and partnerships with schools in other countries. With this in mind, we set out to explore what motivates, supports and inhibits medical educators who wish to or might work outside their "home country". This article reports on the pilot stage (in specific organizational contexts in Middle East) of a longitudinal project aimed at canvassing medical educators on a broader global scale, using reflective accounts and a questionnaire survey. The findings from this pilot study raise interesting issues about the lived experience of medical educators who have chosen to work in a different culture from their own. Respondents identify many advantages around skills, personal and professional development. Three main issues emerged in terms of educators' experiences: the academic environment, medical practice in a different cultural context and personal matters. Adapting to the local culture, gender segregation and the impact on learning and teaching was an overarching factor. We introduce an explanatory framework to explain the development of international educator identity, a cyclical process in which, through experiences and reflection, individual world views and perspectives are continually modified and developed. This pilot study tested the methodologies and developed a new conceptual model that will be used in a wider study across different cultures.

Exploring Operational Safeguards, Safety, and Security by Design to Address Real Time Threats in Nuclear Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schanfein, Mark J.; Mladineo, Stephen V.

2015-07-07

Over the last few years, significant attention has been paid to both encourage application and provide domestic and international guidance for designing in safeguards and security in new facilities.1,2,3 However, once a facility is operational, safeguards, security, and safety often operate as separate entities that support facility operations. This separation is potentially a serious weakness should insider or outsider threats become a reality.Situations may arise where safeguards detects a possible loss of material in a facility. Will they notify security so they can, for example, check perimeter doors for tampering? Not doing so might give the advantage to an insidermore » who has already, or is about to, move nuclear material outside the facility building. If outsiders break into a facility, the availability of any information to coordinate the facility’s response through segregated alarm stations or a failure to include all available radiation sensors, such as safety’s criticality monitors can give the advantage to the adversary who might know to disable camera systems, but would most likely be unaware of other highly relevant sensors in a nuclear facility.This paper will briefly explore operational safeguards, safety, and security by design (3S) at a high level for domestic and State facilities, identify possible weaknesses, and propose future administrative and technical methods, to strengthen the facility system’s response to threats.« less

Features of spatial and functional segregation and integration of the primate connectome revealed by trade-off between wiring cost and efficiency

PubMed Central

Chen, Yuhan; Wang, Shengjun

2017-01-01

The primate connectome, possessing a characteristic global topology and specific regional connectivity profiles, is well organized to support both segregated and integrated brain function. However, the organization mechanisms shaping the characteristic connectivity and its relationship to functional requirements remain unclear. The primate brain connectome is shaped by metabolic economy as well as functional values. Here, we explored the influence of two competing factors and additional advanced functional requirements on the primate connectome employing an optimal trade-off model between neural wiring cost and the representative functional requirement of processing efficiency. Moreover, we compared this model with a generative model combining spatial distance and topological similarity, with the objective of statistically reproducing multiple topological features of the network. The primate connectome indeed displays a cost-efficiency trade-off and that up to 67% of the connections were recovered by optimal combination of the two basic factors of wiring economy and processing efficiency, clearly higher than the proportion of connections (56%) explained by the generative model. While not explicitly aimed for, the trade-off model captured several key topological features of the real connectome as the generative model, yet better explained the connectivity of most regions. The majority of the remaining 33% of connections unexplained by the best trade-off model were long-distance links, which are concentrated on few cortical areas, termed long-distance connectors (LDCs). The LDCs are mainly non-hubs, but form a densely connected group overlapping on spatially segregated functional modalities. LDCs are crucial for both functional segregation and integration across different scales. These organization features revealed by the optimization analysis provide evidence that the demands of advanced functional segregation and integration among spatially distributed regions may play a significant role in shaping the cortical connectome, in addition to the basic cost-efficiency trade-off. These findings also shed light on inherent vulnerabilities of brain networks in diseases. PMID:28961235

Features of spatial and functional segregation and integration of the primate connectome revealed by trade-off between wiring cost and efficiency.

PubMed

Chen, Yuhan; Wang, Shengjun; Hilgetag, Claus C; Zhou, Changsong

2017-09-01

The primate connectome, possessing a characteristic global topology and specific regional connectivity profiles, is well organized to support both segregated and integrated brain function. However, the organization mechanisms shaping the characteristic connectivity and its relationship to functional requirements remain unclear. The primate brain connectome is shaped by metabolic economy as well as functional values. Here, we explored the influence of two competing factors and additional advanced functional requirements on the primate connectome employing an optimal trade-off model between neural wiring cost and the representative functional requirement of processing efficiency. Moreover, we compared this model with a generative model combining spatial distance and topological similarity, with the objective of statistically reproducing multiple topological features of the network. The primate connectome indeed displays a cost-efficiency trade-off and that up to 67% of the connections were recovered by optimal combination of the two basic factors of wiring economy and processing efficiency, clearly higher than the proportion of connections (56%) explained by the generative model. While not explicitly aimed for, the trade-off model captured several key topological features of the real connectome as the generative model, yet better explained the connectivity of most regions. The majority of the remaining 33% of connections unexplained by the best trade-off model were long-distance links, which are concentrated on few cortical areas, termed long-distance connectors (LDCs). The LDCs are mainly non-hubs, but form a densely connected group overlapping on spatially segregated functional modalities. LDCs are crucial for both functional segregation and integration across different scales. These organization features revealed by the optimization analysis provide evidence that the demands of advanced functional segregation and integration among spatially distributed regions may play a significant role in shaping the cortical connectome, in addition to the basic cost-efficiency trade-off. These findings also shed light on inherent vulnerabilities of brain networks in diseases.

An agent-based simulation of persistent inequalities in health behavior: Understanding the interdependent roles of segregation, clustering, and social influence.

PubMed

Langellier, Brent A

2016-12-01

Health inequalities are conspicuously persistent through time and often durable even in spite of interventions. In this study, I use agent-based simulation models (ABMs) to understand how the complex interrelationships between residential segregation, social network formation, group-level preferences, and social influence may contribute to this persistence. I use a more-stylized ABM, Bubblegum Village (BV), to understand how initial inequalities in bubblegum-chewing behaviors either endure, increase, or decrease over time given group-level differences in preferences, neighborhood-level barriers or facilitators of bubblegum chewing (e.g., access to bubblegum shops), and agents' preferences for segregation, homophily, and clustering (i.e., the 'tightness' of social networks). I further use BV to understand whether segregation and social network characteristics impact whether the effects of a bubblegum-reduction intervention that is very effective in the short term are durable over time, as well as to identify intervention strategies to reduce attenuation of the intervention effects. In addition to BV, I also present results from an ABM based on the distribution and social characteristics of the population in Philadelphia, PA. This model explores similar questions to BV, but examines racial/ethnic inequalities in soda consumption based on agents' social characteristics and baseline soda consumption probabilities informed by the 2007-2010 National Health and Nutrition Examination Survey. Collectively, the models suggest that residential segregation is a fundamental process for the production and persistence of health inequalities. The other major conclusion of the study is that, for behaviors that are subject to social influence and that cluster within social groups, interventions that are randomly-targeted to individuals with 'bad' behaviors will likely experience a large degree of recidivism to pre-intervention behaviors. In contrast, interventions that target multiple members of the same network, as well as multilevel interventions that include a neighborhood-level component, can reduce recidivism.

Effect of antimony segregation on the electronic properties of InAs/InAsSb superlattices

NASA Astrophysics Data System (ADS)

Haugan, H. J.; Szmulowicz, F.; Hudgins, J. J.; Cordonnier, L. E.; Brown, G. J.

2017-08-01

There has been great progress in recent years in advancing the state-of-the-art of Ga-free InAs/InAsSb superlattice (SL) materials for infrared detector applications, spurred by the observation of long minority carrier lifetimes in this material system. However, compositional and dimensional changes through antimony (Sb) segregation alter the detector properties from those originally designed. For this reason, in this work, the authors explore epitaxial conditions that can mitigate this segregation in order to produce high-quality SL materials for optimum detector performance. A nominal SL structure of 7.7 nm InAs/3.5 nm InAs0.7 Sb0.3 tailored for an approximately six-micron response at 5 K was used to optimize the epitaxial parameters. Since the growth of mixed AsSb alloys is complicated by the potential reaction of As with Sb surfaces, the authors vary the substrate temperature (Ts) in order to control the As surface reaction on a Sb surface. Experimental results indicate that the SL sample grown at the lowest investigated Ts produces the highest Sb-mole fraction x of 0.3 in InAs1-x Sbx layers, which then decreases by 21 % as the Ts increases from 395 to 440 °C. This reduction causes an approximately 30 meV blueshift in the position of the excitonic photoluminescence (PL) peak. This finding differs from the results obtained from the Ga-containing InAs/GaSb SL equivalents, where the PL peak position remains constant at about 220 meV, regardless of Ts. The Ga-free SLs generally generate a broader PL linewidth than the corresponding Ga-containing SLs due to the higher spatial Sb distribution at the hetero-interfaces engendered by Sb segregation. In order for this newly proposed Ga-free SL materials to be viable for detector applications, the material problem associated with Sb segregation needs to be adequately controlled and further mitigated.

Grain size segregation in debris discs

NASA Astrophysics Data System (ADS)

Thebault, P.; Kral, Q.; Augereau, J.-C.

2014-01-01

Context. In most debris discs, dust grain dynamics is strongly affected by stellar radiation pressure. Because this mechanism is size-dependent, we expect dust grains to be spatially segregated according to their sizes. However, because of the complex interplay between radiation pressure, grain processing by collisions, and dynamical perturbations, this spatial segregation of the particle size distribution (PSD) has proven difficult to investigate and quantify with numerical models. Aims: We propose to thoroughly investigate this problem by using a new-generation code that can handle some of the complex coupling between dynamical and collisional effects. We intend to explore how PSDs behave in both unperturbed discs at rest and in discs pertubed by planetary objects. Methods: We used the DyCoSS code to investigate the coupled effect of collisions, radiation pressure, and dynamical perturbations in systems that have reached a steady-state. We considered two setups: a narrow ring perturbed by an exterior planet, and an extended disc into which a planet is embedded. For both setups we considered an additional unperturbed case without a planet. We also investigated the effect of possible spatial size segregation on disc images at different wavelengths. Results: We find that PSDs are always spatially segregated. The only case for which the PSD follows a standard dn ∝ s-3.5ds law is for an unperturbed narrow ring, but only within the parent-body ring itself. For all other configurations, the size distributions can strongly depart from such power laws and have steep spatial gradients. As an example, the geometrical cross-section of the disc is very rarely dominated by the smallest grains on bound orbits, as it is expected to be in standard PSDs in sq with q ≤ -3. Although the exact profiles and spatial variations of PSDs are a complex function of the set-up that is considered, we are still able to derive some reliable results that will be useful for image or SED-fitting models of observed discs.

Segregation of Clock and Non-Clock Regulatory Functions of REV-ERB.

PubMed

Butler, Andrew A; Burris, Thomas P

2015-08-04

The molecular clock is a master controller of circadian cellular processes that affect growth, metabolic homeostasis, and behavior. A report in Science by Zhang et al. (2015) redefines our understanding of how Rev-erba acts as an internal feedback inhibitor that modulates activity of the core clock while simultaneously regulating tissue-specific metabolic processes. Copyright © 2015 Elsevier Inc. All rights reserved.

Male group size, female distribution and changes in sexual segregation by Roosevelt elk

PubMed Central

Peterson, Leah M.

2017-01-01

Sexual segregation, or the differential use of space by males and females, is hypothesized to be a function of body size dimorphism. Sexual segregation can also manifest at small (social segregation) and large (habitat segregation) spatial scales for a variety of reasons. Furthermore, the connection between small- and large-scale sexual segregation has rarely been addressed. We studied a population of Roosevelt elk (Cervus elaphus roosevelti) across 21 years in north coastal California, USA, to assess small- and large-scale sexual segregation in winter. We hypothesized that male group size would associate with small-scale segregation and that a change in female distribution would associate with large-scale segregation. Variation in forage biomass might also be coupled to small and large-scale sexual segregation. Our findings were consistent with male group size associating with small-scale segregation and a change in female distribution associating with large-scale segregation. Females appeared to avoid large groups comprised of socially dominant males. Males appeared to occupy a habitat vacated by females because of a wider forage niche, greater tolerance to lethal risks, and, perhaps, to reduce encounters with other elk. Sexual segregation at both spatial scales was a poor predictor of forage biomass. Size dimorphism was coupled to change in sexual segregation at small and large spatial scales. Small scale segregation can seemingly manifest when all forage habitat is occupied by females and large scale segregation might happen when some forage habitat is not occupied by females. PMID:29121076

America's Urban Crisis and the Advent of Color-Blind Politics: Education, Incarceration, Segregation, and the Future of the U.S. Multiracial Democracy

ERIC Educational Resources Information Center

Ivery, Curtis, Ed.; Bassett, Joshua, Ed.

2011-01-01

Over 40 years ago the historic Kerner Commission Report declared that America was undergoing an urban crisis whose effects were disproportionately felt by underclass populations. In "America's Urban Crisis and the Advent of Color-blind Politics", Curtis Ivery and Joshua Bassett explore the persistence of this crisis today, despite public…

Two Visual Pathways in Primates Based on Sampling of Space: Exploitation and Exploration of Visual Information

PubMed Central

Sheth, Bhavin R.; Young, Ryan

2016-01-01

Evidence is strong that the visual pathway is segregated into two distinct streams—ventral and dorsal. Two proposals theorize that the pathways are segregated in function: The ventral stream processes information about object identity, whereas the dorsal stream, according to one model, processes information about either object location, and according to another, is responsible in executing movements under visual control. The models are influential; however recent experimental evidence challenges them, e.g., the ventral stream is not solely responsible for object recognition; conversely, its function is not strictly limited to object vision; the dorsal stream is not responsible by itself for spatial vision or visuomotor control; conversely, its function extends beyond vision or visuomotor control. In their place, we suggest a robust dichotomy consisting of a ventral stream selectively sampling high-resolution/focal spaces, and a dorsal stream sampling nearly all of space with reduced foveal bias. The proposal hews closely to the theme of embodied cognition: Function arises as a consequence of an extant sensory underpinning. A continuous, not sharp, segregation based on function emerges, and carries with it an undercurrent of an exploitation-exploration dichotomy. Under this interpretation, cells of the ventral stream, which individually have more punctate receptive fields that generally include the fovea or parafovea, provide detailed information about object shapes and features and lead to the systematic exploitation of said information; cells of the dorsal stream, which individually have large receptive fields, contribute to visuospatial perception, provide information about the presence/absence of salient objects and their locations for novel exploration and subsequent exploitation by the ventral stream or, under certain conditions, the dorsal stream. We leverage the dichotomy to unify neuropsychological cases under a common umbrella, account for the increased prevalence of multisensory integration in the dorsal stream under a Bayesian framework, predict conditions under which object recognition utilizes the ventral or dorsal stream, and explain why cells of the dorsal stream drive sensorimotor control and motion processing and have poorer feature selectivity. Finally, the model speculates on a dynamic interaction between the two streams that underscores a unified, seamless perception. Existing theories are subsumed under our proposal. PMID:27920670

Two Visual Pathways in Primates Based on Sampling of Space: Exploitation and Exploration of Visual Information.

PubMed

Sheth, Bhavin R; Young, Ryan

2016-01-01

Evidence is strong that the visual pathway is segregated into two distinct streams-ventral and dorsal. Two proposals theorize that the pathways are segregated in function: The ventral stream processes information about object identity, whereas the dorsal stream, according to one model, processes information about either object location, and according to another, is responsible in executing movements under visual control. The models are influential; however recent experimental evidence challenges them, e.g., the ventral stream is not solely responsible for object recognition; conversely, its function is not strictly limited to object vision; the dorsal stream is not responsible by itself for spatial vision or visuomotor control; conversely, its function extends beyond vision or visuomotor control. In their place, we suggest a robust dichotomy consisting of a ventral stream selectively sampling high-resolution/ focal spaces, and a dorsal stream sampling nearly all of space with reduced foveal bias. The proposal hews closely to the theme of embodied cognition: Function arises as a consequence of an extant sensory underpinning. A continuous, not sharp, segregation based on function emerges, and carries with it an undercurrent of an exploitation-exploration dichotomy. Under this interpretation, cells of the ventral stream, which individually have more punctate receptive fields that generally include the fovea or parafovea, provide detailed information about object shapes and features and lead to the systematic exploitation of said information; cells of the dorsal stream, which individually have large receptive fields, contribute to visuospatial perception, provide information about the presence/absence of salient objects and their locations for novel exploration and subsequent exploitation by the ventral stream or, under certain conditions, the dorsal stream. We leverage the dichotomy to unify neuropsychological cases under a common umbrella, account for the increased prevalence of multisensory integration in the dorsal stream under a Bayesian framework, predict conditions under which object recognition utilizes the ventral or dorsal stream, and explain why cells of the dorsal stream drive sensorimotor control and motion processing and have poorer feature selectivity. Finally, the model speculates on a dynamic interaction between the two streams that underscores a unified, seamless perception. Existing theories are subsumed under our proposal.

Heider balance, asymmetric ties, and gender segregation

NASA Astrophysics Data System (ADS)

Krawczyk, Małgorzata J.; del Castillo-Mussot, Marcelo; Hernández-Ramírez, Eric; Naumis, Gerardo G.; Kułakowski, Krzysztof

2015-12-01

To remove a cognitive dissonance in interpersonal relations, people tend to divide their acquaintances into friendly and hostile parts, both groups internally friendly and mutually hostile. This process is modeled as an evolution toward the Heider balance. A set of differential equations have been proposed and validated (Kułakowski et al., 2005) to model the Heider dynamics of this social and psychological process. Here we generalize the model by including the initial asymmetry of the interpersonal relations and the direct reciprocity effect which removes this asymmetry. Our model is applied to the data on enmity and friendship in 37 school classes and 4 groups of teachers in México. For each class, a stable balanced partition is obtained into two groups. The gender structure of the groups reveals stronger gender segregation in younger classes, i.e. of age below 12 years, a fact consistent with other general empirical results.

Race and Space in the 1990s: Changes in the Geographic Scale of Racial Residential Segregation, 1990-2000

PubMed Central

Reardon, Sean F.; Farrell, Chad R.; Matthews, Stephen A.; O'Sullivan, David; Bischoff, Kendra; Firebaugh, Glenn

2014-01-01

We use newly developed methods of measuring spatial segregation across a range of spatial scales to assess changes in racial residential segregation patterns in the 100 largest U.S. metropolitan areas from 1990 to 2000. Our results point to three notable trends in segregation from 1990 to 2000: 1) Hispanic-white and Asian-white segregation levels increased at both micro- and macro-scales; 2) black-white segregation declined at a micro-scale, but was unchanged at a macro-scale; and 3) for all three racial groups and for almost all metropolitan areas, macro-scale segregation accounted for more of the total metropolitan area segregation in 2000 than in 1990. Our examination of the variation in these trends among the metropolitan areas suggests that Hispanic-white and Asian-white segregation changes have been driven largely by increases in macro-scale segregation resulting from the rapid growth of the Hispanic and Asian populations in central cities. The changes in black-white segregation, in contrast, appear to be driven by the continuation of a 30-year trend in declining micro-segregation, coupled with persistent and largely stable patterns of macro-segregation. PMID:19569292

Molecular phylogeny of Subtribe Artemisiinae (Asteraceae), including Artemisia and its allied and segregate genera

PubMed Central

Watson, Linda E; Bates, Paul L; Evans, Timothy M; Unwin, Matthew M; Estes, James R

2002-01-01

Background Subtribe Artemisiinae of Tribe Anthemideae (Asteraceae) is composed of 18 largely Asian genera that include the sagebrushes and mugworts. The subtribe includes the large cosmopolitan, wind-pollinated genus Artemisia, as well as several smaller genera and Seriphidium, that altogether comprise the Artemisia-group. Circumscription and taxonomic boundaries of Artemisia and the placements of these small segregate genera is currently unresolved. Results We constructed a molecular phylogeny for the subtribe using the internal transcribed spacers (ITS) of nuclear ribosomal DNA analyzed with parsimony, likelihood, and Bayesian criteria. The resulting tree is comprised of three major clades that correspond to the radiate genera (e.g., Arctanthemum and Dendranthema), and two clades of Artemisia species. All three clades have allied and segregate genera embedded within each. Conclusions The data support a broad concept of Artemisia s.l. that includes Neopallasia, Crossostephium, Filifolium, Seriphidium, and Sphaeromeria. However, the phylogeny excludes Elachanthemum, Kaschgaria, and Stilnolepis from the Artemisia-group. Additionally, the monophyly of the four subgenera of Artemisia is also not supported, with the exception of subg. Dracunculus. Homogamous, discoid capitula appear to have arisen in parallel four to seven times, with the loss of ray florets. Thus capitular morphology is not a reliable taxonomic character, which traditionally has been one of the defining characters. PMID:12350234

Irradiation-induced sensitization and stress corrosion cracking of Type 304 stainless steel core-internal components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, H.M.; Ruther, W.E.; Sanecki, J.E.

1991-08-01

High- and commercial-purity heats of Type 304 stainless steel, obtained from neutron absorber tubes after irradiation to fluence levels of up to 2 {times} 10{sup 21} n{center dot}cm{sup {minus}2} (E > 1 MeV) in two boiling water reactors, were examined by Auger electron spectroscopy to characterize irradiation-induced grain- boundary segregation and depletion of alloying and impurity elements. Segregation of Si, P, Ni, and an unidentified element or compound that gives rise to an Auger energy peak at 59 eV was observed in the commercial-purity heat. Such segregation was negligible in high-purity material, except for Ni. No evidence of S segregationmore » was observed in either material. Cr depletion was more pronounced in the high-purity material than in the commercial-purity material. These observations suggest a synergism between the significant level of impurities and Cr depletion in the commercial-purity heat. In the absence of such synergism, Cr depletion appears more pronounced in the high-purity heat. Initial results of constant-extension-rate tests conducted on the two heats in air an in simulated BWR water were correlated with the results from analysis by Auger electron spectroscopy. 15 refs., 10 figs.« less

On the Alternate Stirring Mode of F-EMS for Bloom Continuous Castings

NASA Astrophysics Data System (ADS)

Sun, Haibo; Li, Liejun; Ye, Dexin; Wu, Xuexing

2018-05-01

Local solute transportation behaviors under different alternate stirring parameters of final electromagnetic stirring (F-EMS) and their influences on the internal quality of the as-cast bloom are compared and evaluated based on a developed coupled model of electromagnetism, heat, and solute transport. To this end, plant trials were conducted in Shaoguan Steel, China. Under the action of F-EMS, a negative segregation band in an ellipse shape is observed at the central area of strand cross section, where the minimum carbon segregation degree is decreased from 0.98 to 0.84 as the stirring duration increases from 15 to 35 seconds in the alternate stirring mode, while it is reduced to 0.805 in the continuous stirring mode. The white band and shrinkage cavity are simultaneously observed at strand center under the conditions of continuous stirring mode, and alternate stirring mode with a stirring period of 35 seconds because of the local over-sustaining melt rotation. In contrast, the V-shape porosity belt width and strand center segregation fluctuation range increase from 60 to 90 mm and from 0.12 to 0.30, respectively, as the stirring duration is reduced from 25 to 15 seconds in the alternate stirring mode because of the poor mixing of the local melt at the strand center.

The Strata-1 experiment on small body regolith segregation

NASA Astrophysics Data System (ADS)

Fries, Marc; Abell, Paul; Brisset, Julie; Britt, Daniel; Colwell, Joshua; Dove, Adrienne; Durda, Dan; Graham, Lee; Hartzell, Christine; Hrovat, Kenneth; John, Kristen; Karrer, Dakotah; Leonard, Matthew; Love, Stanley; Morgan, Joseph; Poppin, Jayme; Rodriguez, Vincent; Sánchez-Lana, Paul; Scheeres, Dan; Whizin, Akbar

2018-01-01

The Strata-1 experiment studies the mixing and segregation dynamics of regolith on small bodies by exposing a suite of regolith simulants to the microgravity environment aboard the International Space Station (ISS) for one year. This will improve our understanding of regolith dynamics and properties on small asteroids, and may assist in interpreting analyses of samples from missions to small bodies such as OSIRIS-REx, Hayabusa-1 and -2, and future missions to small bodies. The Strata-1 experiment consists of four evacuated tubes partially filled with regolith simulants. The simulants are chosen to represent models of regolith covering a range of complexity and tailored to inform and improve computational studies. The four tubes are regularly imaged while moving in response to the ambient vibrational environment using dedicated cameras. The imagery is then downlinked to the Strata-1 science team about every two months. Analyses performed on the imagery includes evaluating the extent of the segregation of Strata-1 samples and comparing the observations to computational models. After Strata-1's return to Earth, x-ray tomography and optical microscopy will be used to study the post-flight simulant distribution. Strata-1 is also a pathfinder for the new "1E" ISS payload class, which is intended to simplify and accelerate emplacement of experiments on board ISS.

Differential phytosociological interactions involving male and female atriplex bonnevillensis

USGS Publications Warehouse

Sinclair, J.; Emlen, J.M.; Rinella, M.; Snelgrove, J.; Freeman, D.C.

2009-01-01

Wind-pollinated dioecious plants often exhibit spatial segregation of the sexes. This partial niche separation has most often been explored using abiotic niche axes. However, if the sexes are truly separated in space, then they are apt to encounter different plant species that may heavily affect growth and reproduction. Also, to the extent that their niches differ, the sexes may respond differently to the same co-occurring species. Here we examine interspecific interactions that influence male and female reproductive potential in Atriplex bonnevillensis. Using Emlen's interaction assessment, a technique which assesses species interactions based on cover classes, we show that Salsola species compete significantly with females but not males, while Halogeton glomeratus competes with males but not females. The effect of competition only became apparent when we corrected for site-specific fertility. These results imply that differential competition must be considered when studying dioecious plants that display spatial segregation of the sexes.

Numerical Investigation of Vertical Plunging Jet Using a Hybrid Multifluid–VOF Multiphase CFD Solver

DOE PAGES

Shonibare, Olabanji Y.; Wardle, Kent E.

2015-06-28

A novel hybrid multiphase flow solver has been used to conduct simulations of a vertical plunging liquid jet. This solver combines a multifluid methodology with selective interface sharpening to enable simulation of both the initial jet impingement and the long-time entrained bubble plume phenomena. Models are implemented for variable bubble size capturing and dynamic switching of interface sharpened regions to capture transitions between the initially fully segregated flow types into the dispersed bubbly flow regime. It was found that the solver was able to capture the salient features of the flow phenomena under study and areas for quantitative improvement havemore » been explored and identified. In particular, a population balance approach is employed and detailed calibration of the underlying models with experimental data is required to enable quantitative prediction of bubble size and distribution to capture the transition between segregated and dispersed flow types with greater fidelity.« less

Centromeric Heterochromatin: The Primordial Segregation Machine

PubMed Central

Bloom, Kerry S.

2014-01-01

Centromeres are specialized domains of heterochromatin that provide the foundation for the kinetochore. Centromeric heterochromatin is characterized by specific histone modifications, a centromere-specific histone H3 variant (CENP-A), and the enrichment of cohesin, condensin, and topo-isomerase II. Centromere DNA varies orders of magnitude in size from 125 bp (budding yeast) to several megabases (human). In metaphase, sister kinetochores on the surface of replicated chromosomes face away from each other, where they establish microtubule attachment and bi-orientation. Despite the disparity in centromere size, the distance between separated sister kinetochores is remarkably conserved (approximately 1 μm) throughout phylogeny. The centromere functions as a molecular spring that resists microtubule-based extensional forces in mitosis. This review explores the physical properties of DNA in order to understand how the molecular spring is built and how it contributes to the fidelity of chromosome segregation. PMID:25251850

Relationship between ecomorphology and trophic segregation in four closely related sympatric fish species (Teleostei, Sciaenidae).

PubMed

Blasina, Gabriela; Molina, Juan; Lopez Cazorla, Andrea; Díaz de Astarloa, Juan

This study explores the relationship between ecomorphology and trophic segregation in four closely related sympatric fish species (Teleostei, Sciaenidae) that are known to differ in their trophic habits. Only adult specimens were analyzed: 103 Cynoscion guatucupa, 77 Pogonias cromis, 61 Micropogonias furnieri, and 48 Menticirrhus americanus. The four species presented divergent ecomorphological traits related to swimming agility, prey spotting and capture, and the potential size of prey they were able to swallow. Results suggest that these sciaenid species can partition the food resources, even though they completely overlap in space. Differences in their ecomorphological traits appear to correlate closely with the diet and consequently could explain the trophic differentiation observed. Arguably, these ecomorphological differences play a significant role in the coexistence of the adults of these sympatric fish species. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Polymorphic mimicry, microhabitat use, and sex-specific behaviour.

PubMed

Joron, M

2005-05-01

In order to assess the adaptive importance of microhabitat segregation for the maintenance of mimetic diversity, I explore how flight height varies between the sympatric forms of the polymorphic butterfly Heliconius numata and their respective models in the genus Melinaea. There is no evidence for vertical stratification of mimicry rings in these tiger-patterned butterflies, but males of H. numata tend to fly significantly higher than females and the Melinaea models. This difference in microhabitat preference likely results from females searching for host plants whereas males are patrolling for mates. I then present an extension of Muller's mimicry model for the case of partial behavioural or spatial segregation of sexes. The analysis suggests that sex-specific behaviours can make mimicry more beneficial, simply by reducing the effective population size participating in mimicry. The interaction between mimicry and sex-specific behaviours may therefore facilitate the evolution of polymorphism via enhanced, fine-scale local adaptation.

Field Evaluation of Temperature Differential in HMA Mixtures

DOT National Transportation Integrated Search

2012-05-15

Segregation is a common occurrence in hot mix asphalt (HMA) construction. The two types of : segregation encountered are gradation segregation and thermal segregation. This investigation report : involves mainly thermal segregation, which occurs when...

Analysis of surface segregation in polymer mixtures: A combination of mean field and statistical associated fluid theories

NASA Astrophysics Data System (ADS)

Krawczyk, Jaroslaw; Croce, Salvatore; Chakrabarti, Buddhapriya; Tasche, Jos

The surface segregation in polymer mixtures remains a challenging problem for both academic exploration as well as industrial applications. Despite its ubiquity and several theoretical attempts a good agreement between computed and experimentally observed profiles has not yet been achieved. A simple theoretical model proposed in this context by Schmidt and Binder combines Flory-Huggins free energy of mixing with the square gradient theory of wetting of a wall by fluid. While the theory gives us a qualitative understanding of the surface induced segregation and the surface enrichment it lacks the quantitative comparison with the experiment. The statistical associating fluid theory (SAFT) allows us to calculate accurate free energy for a real polymeric materials. In an earlier work we had shown that increasing the bulk modulus of a polymer matrix through which small molecules migrate to the free surface causes reduction in the surface migrant fraction using Schmidt-Binder and self-consistent field theories. In this work we validate this idea by combining mean field theories and SAFT to identify parameter ranges where such an effect should be observable. Department of Molecular Physics, Łódź University of Technology, Żeromskiego 116, 90-924 Łódź, Poland.

A hybrid technique for speech segregation and classification using a sophisticated deep neural network

PubMed Central

Nawaz, Tabassam; Mehmood, Zahid; Rashid, Muhammad; Habib, Hafiz Adnan

2018-01-01

Recent research on speech segregation and music fingerprinting has led to improvements in speech segregation and music identification algorithms. Speech and music segregation generally involves the identification of music followed by speech segregation. However, music segregation becomes a challenging task in the presence of noise. This paper proposes a novel method of speech segregation for unlabelled stationary noisy audio signals using the deep belief network (DBN) model. The proposed method successfully segregates a music signal from noisy audio streams. A recurrent neural network (RNN)-based hidden layer segregation model is applied to remove stationary noise. Dictionary-based fisher algorithms are employed for speech classification. The proposed method is tested on three datasets (TIMIT, MIR-1K, and MusicBrainz), and the results indicate the robustness of proposed method for speech segregation. The qualitative and quantitative analysis carried out on three datasets demonstrate the efficiency of the proposed method compared to the state-of-the-art speech segregation and classification-based methods. PMID:29558485

Atomic scale study of grain boundary segregation before carbide nucleation in Ni-Cr-Fe Alloys

NASA Astrophysics Data System (ADS)

Li, Hui; Xia, Shuang; Liu, Wenqing; Liu, Tingguang; Zhou, Bangxin

2013-08-01

Three dimensional chemical information concerning grain boundary segregation before carbide nucleation was characterized by atom probe tomography in two Ni-Cr-Fe alloys which were aged at 500 °C for 0.5 h after homogenizing treatment. B, C and Si atoms segregation at grain boundary in Alloy 690 was observed. B, C, N and P atoms segregation at grain boundary in 304 austenitic stainless steel was observed. C atoms co-segregation with Cr atoms at the grain boundaries both in Alloy 690 and 304 austenitic stainless steel was found, and its effect on the carbide nucleation was discussed. The amount of each segregated element at grain boundaries in the two Ni-Cr-Fe alloys were analyzed quantitatively. Comparison of the grain boundary segregation features of the two Ni-Cr-Fe alloys were carried out based on the experimental results. The impurity and solute atoms segregate inhomogeneously in the same grain boundary both in 304 SS and Alloy 690. The grain boundary segregation tendencies (Sav) are B (11.8 ± 1.4) > P (5.4 ± 1.4) > N (4.7 ± 0.3) > C (3.7 ± 0.4) in 304 SS, and B (6.9 ± 0.9) > C (6.7 ± 0.4) > Si (1.5 ± 0.2) in Alloy 690. Cr atoms may co-segregate with C atoms at grain boundaries before carbide nucleation at the grain boundaries both in 304 SS and Alloy 690. Ni atoms generally deplete at grain boundary both in 304 SS and Alloy 690. The literature shows that the Ni atoms may co-segregate with P atoms at grain boundaries [28], but the P atoms segregation do not leads to Ni segregation in the current study. In the current study, Fe atoms may segregate or deplete at grain boundary in Alloy 690. But Fe atoms generally deplete at grain boundary in 304 SS. B atoms have the strongest grain boundary segregation tendency both in 304 SS and Alloy 690. The grain boundary segregation tendency and Gibbs free energy of B in 304 SS is higher than in Alloy 690. C atoms are easy to segregate at grain boundaries both in 304 SS and Alloy 690. The grain boundary segregation tendency and Gibbs free energy of C in Alloy 690 is higher than in 304 SS, due to the higher bulk C concentration and the site competition of P atoms which segregate at grain boundary [29,30]. It is imply that the segregation tendency is influenced by the bulk concentration of the segregates. Si atoms slightly segregate at grain boundaries in Alloy 690, but do not segregate at grain boundaries in 304 SS. N and P atoms segregate at grain boundary in 304 SS, and their segregation Gibbs free energy are similar. N atoms may be exhausted by the TiN precipitated in the matrix and can not be observed in the grain boundary of Alloy 690 [19]. Mn atoms deplete at grain boundary in 304 SS. This phenomenon is similar to that of proton irradiation induced segregation in 304 SS [32]. B, C, N, P segregation Gibbs energies are similar both in 304 SS and Alloy 690. B and C atoms segregate at grain boundary both in Alloy 690 and 304 SS, P and N segregate at grain boundary in 304 SS. Si atoms segregate at grain boundary in Alloy 690, but do not segregate at grain boundary in 304 SS. Cr enriches at grain boundary both in Alloy 690 and 304 SS, although carbide does not nucleate. Ni and Fe may segregate, deplete or homogeneously distribute at grain boundary in Alloy 690, but they deplete at grain boundary in 304 SS. C and Cr atoms co-segregate at grain boundaries before carbide nucleation in Alloy 690 and 304 SS. Combination with other results in literatures, the evolution of Cr concentration at grain boundary should be enrichment at grain boundary before carbide nucleation, depletion at grain boundary after carbide precipitation, and healing after obvious growth of carbide. After aging treatment at 500 °C for 0.5 h, the total reduction of grain boundary free energy due to segregation is 27.489 kJ/mol for Alloy 690 and 45.207 kJ/mol for 304.

Mixing, segregation, and flow of granular materials

NASA Astrophysics Data System (ADS)

McCarthy, Joseph J.

1998-11-01

This dissertation addresses mixing, segregation, and flow of granular materials with the ultimate goal of providing fundamental understanding and tools for the rational design and optimization of mixing devices. In particular, the paradigm cases of a slowly rotated tumbler mixer and flow down an inclined plane are examined. Computational work, as well as supporting experiments, are used to probe both two and three dimensional systems. In the avalanching regime, the mixing and flow can be viewed either on a global-scale or a local-scale. On the global-scale, material is transported via avalanches whose gross motion can be well described by geometrical considerations. On the local-scale, the dynamics of the particle motion becomes important; particles follow complicated trajectories that are highly sensitive to differences in size/density/morphology. By decomposing the problem in this way, it is possible to study the implications of the geometry and dynamics separately and to add complexities in a controlled fashion. This methodology allows even seemingly difficult problems (i.e., mixing in non-convex geometries, and mixing of dissimilar particles) to be probed in a simple yet methodical way. In addition this technique provides predictions of optimal mixing conditions in an avalanching tumbler, a criterion for evaluating the effect of mixer shape, and mixing enhancement strategies for both two and three dimensional mixers. In the continuous regime, the flow can be divided into two regions: a rapid flow region of the cascading layer at the free surface, and a fixed bed region undergoing solid body rotation. A continuum-based description, in which averages are taken across the layer, generates quantitative predictions about the flow in the cascading layer and agrees well with experiment. Incorporating mixing through a diffusive flux (as well as constitutive expression for segregation) within the cascading layer allows for the determination of optimal mixing conditions. Segregation requires a detailed understanding of the interplay between the flow and the properties of the particles. A relatively mature simulation technique, particle dynamics (PD), aptly captures these effects and is eminently suited to mixing studies; particle properties can be varied on a particle-by-particle basis and detailed mixed structures are easily captured and visualized. However, PD is computationally intensive and is therefore of questionable general utility. By combining PD and geometrical insight-in essence, by focusing the particle dynamics simulation only where it is needed-a new hybrid method of simulation, which is much faster than a conventional particle dynamics method, can be achieved. This technique can yield more than an order of magnitude increase in computational speed while maintaining the versatility of a particle dynamics simulation. Alternatively, by utilizing PD to explore segregation mechanisms in simple flows-e.g., flow down an inclined plane-heuristic models and constitutive relations for segregation can be tested. Incorporating these segregation flux terms into a continuum description of the flow in a tumbler allows rapid Lagrangian simulation of the competition between mixing and segregation. For the case of density segregation, this produces good agreement between theory and experiment with essentially no adjustable parameters. In addition, an accurate quantitative prediction of the optimal mixing time is obtained.

Prospects for Political Transition in the Islamic Republic of Iran

DTIC Science & Technology

1999-12-01

education, health, and other fields.蕔 Nevertheless, they have also suffered setbacks. Azar Nafisi , of Johns Hopkins University School of...Advanced International Studies describes two such setbacks in the following: 129 Azar Nafisi , "Overload of injustice," St. Paul: Star-Tribune (11 February...133 Nafisi . 134 "Iran’s Parliament Authorizes Gender Segregation of Health Services & Censorship of Women’s Issues," Bethesda: Sisterhood Is

Considerations for implementing machine vision for detecting watercore in apples

NASA Astrophysics Data System (ADS)

Upchurch, Bruce L.; Throop, James A.

1993-05-01

Watercore in apples is a physiological disorder that affects the internal quality of the fruit. Growers can experience serious economic losses due to internal breakdown of the apple if watercored apples are placed unknowingly into long term storage. Economic losses can also occur if watercore is detected and the entire `lot' is downgraded; however, a gain can be obtained if watercored fruit is segregated and marketed as a premium apple soon after harvest. Watercore is characterized by the accumulation of fluid around the vascular bundles replacing air spaces between cells. This fluid reduces the light scattering properties of the apple. Using machine vision to measure the amount of light transmitted through the apple, watercored apples were segregated according to the severity of damage. However, the success of the method was dependent upon two factors. First, the sensitivity of the camera dictated the classes of watercore that could be detected. A highly sensitive camera could separate the less severe classes at the expense of not distinguishing between the more severe classes. A second factor which is common to most quality attributes in perishable commodities is the elapsed time after harvest at which the measurement was made. At the end of the study, light transmission levels decreased to undetectable levels with the initial camera settings for all watercore classes.

Interface segregation behavior in thermal aged austenitic precipitation strengthened stainless steel.

PubMed

Li, Hui; Song, Hui; Liu, Wenqing; Xia, Shuang; Zhou, Bangxin; Su, Cheng; Ding, Wenyan

2015-12-01

The segregation of various elements at grain boundaries, precipitate/matrix interfaces were analyzed using atom probe tomography in an austenitic precipitation strengthened stainless steel aged at 750 °C for different time. Segregation of P, B and C at all types of interfaces in all the specimens were observed. However, Si segregated at all types of interfaces only in the specimen aged for 16 h. Enrichment of Ti at grain boundaries was evident in the specimen aged for 16 h, while Ti did not segregate at other interfaces. Mo varied considerably among interface types, e.g. from segregated at grain boundaries in the specimens after all the aging time to never segregate at γ'/γ phase interfaces. Cr co-segregated with C at grain boundaries, although carbides still did not nucleate at grain boundaries yet. Despite segregation tendency variations in different interface types, the segregation tendency evolution variation of different elements depending aging time were analyzed among all types of interfaces. Based on the experimental results, the enrichment factors, Gibbs interface excess and segregation free energies of segregated elements were calculated and discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Effective search for stable segregation configurations at grain boundaries with data-mining techniques

NASA Astrophysics Data System (ADS)

Kiyohara, Shin; Mizoguchi, Teruyasu

2018-03-01

Grain boundary segregation of dopants plays a crucial role in materials properties. To investigate the dopant segregation behavior at the grain boundary, an enormous number of combinations have to be considered in the segregation of multiple dopants at the complex grain boundary structures. Here, two data mining techniques, the random-forests regression and the genetic algorithm, were applied to determine stable segregation sites at grain boundaries efficiently. Using the random-forests method, a predictive model was constructed from 2% of the segregation configurations and it has been shown that this model could determine the stable segregation configurations. Furthermore, the genetic algorithm also successfully determined the most stable segregation configuration with great efficiency. We demonstrate that these approaches are quite effective to investigate the dopant segregation behaviors at grain boundaries.

Development of Structural Covariance From Childhood to Adolescence: A Longitudinal Study in 22q11.2DS.

PubMed

Sandini, Corrado; Zöller, Daniela; Scariati, Elisa; Padula, Maria C; Schneider, Maude; Schaer, Marie; Van De Ville, Dimitri; Eliez, Stephan

2018-01-01

Background: Schizophrenia is currently considered a neurodevelopmental disorder of connectivity. Still few studies have investigated how brain networks develop in children and adolescents who are at risk for developing psychosis. 22q11.2 Deletion Syndrome (22q11DS) offers a unique opportunity to investigate the pathogenesis of schizophrenia from a neurodevelopmental perspective. Structural covariance (SC) is a powerful approach to explore morphometric relations between brain regions that can furthermore detect biomarkers of psychosis, both in 22q11DS and in the general population. Methods: Here we implement a state-of-the-art sliding-window approach to characterize maturation of SC network architecture in a large longitudinal cohort of patients with 22q11DS (110 with 221 visits) and healthy controls (117 with 211 visits). We furthermore propose a new clustering-based approach to group regions according to trajectories of structural connectivity maturation. We correlate measures of SC with development of working memory, a core executive function that is highly affected in both idiopathic psychosis and 22q11DS. Finally, in 22q11DS we explore correlations between SC dysconnectivity and severity of internalizing psychopathology. Results: In HCs network architecture underwent a quadratic developmental trajectory maturing up to mid-adolescence. Late-childhood maturation was particularly evident for fronto-parietal cortices, while Default-Mode-Network-related regions showed a more protracted linear development. Working memory performance was positively correlated with network segregation and fronto-parietal connectivity. In 22q11DS, we demonstrate aberrant maturation of SC with disturbed architecture selectively emerging during adolescence and correlating more severe internalizing psychopathology. Patients also presented a lack of typical network development during late-childhood, that was particularly prominent for frontal connectivity. Conclusions: Our results suggest that SC maturation may underlie critical cognitive development occurring during late-childhood in healthy controls. Aberrant trajectories of SC maturation may reflect core developmental features of 22q11DS, including disturbed cognitive maturation during childhood and predisposition to internalizing psychopathology and psychosis during adolescence.

49 CFR 176.80 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Segregation Requirements § 176.80 Applicability. (a) This subpart sets forth segregation requirements in addition to any segregation requirements set forth elsewhere in this subchapter. (b) Hazardous materials in... segregation requirements of this subpart and any additional segregation specified in this subchapter for...

49 CFR 176.80 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Segregation Requirements § 176.80 Applicability. (a) This subpart sets forth segregation requirements in addition to any segregation requirements set forth elsewhere in this subchapter. (b) Hazardous materials in... segregation requirements of this subpart and any additional segregation specified in this subchapter for...

The New Segregation.

ERIC Educational Resources Information Center

Laosa, Luis M.

2001-01-01

This issue reviews national demographic trends in school segregation, summarizing research findings. Though the national debate on school segregation emphasizes blacks and whites, present-day school segregation includes segregation by socioeconomic level, ethnicity, and native language. The research study examined features of the ecology of…

Determination of the liquidus temperature of tin using the heat pulse-based melting and comparison with traditional methods

NASA Astrophysics Data System (ADS)

Joung, Wukchul; Park, Jihye; Pearce, Jonathan V.

2018-06-01

In this work, the liquidus temperature of tin was determined by melting the sample using the pressure-controlled loop heat pipe. Square wave-type pressure steps generated periodic 0.7 °C temperature steps in the isothermal region in the vicinity of the tin sample, and the tin was melted with controllable heat pulses from the generated temperature changes. The melting temperatures at specific melted fractions were measured, and they were extrapolated to the melted fraction of unity to determine the liquidus temperature of tin. To investigate the influence of the impurity distribution on the melting behavior, a molten tin sample was solidified by an outward slow freezing or by quenching to segregate the impurities inside the sample with concentrations increasing outwards or to spread the impurities uniformly, respectively. The measured melting temperatures followed the local solidus temperature variations well in the case of the segregated sample and stayed near the solidus temperature in the quenched sample due to the microscopic melting behavior. The extrapolated melting temperatures of the segregated and quenched samples were 0.95 mK and 0.49 mK higher than the outside-nucleated freezing temperature of tin (with uncertainties of 0.15 mK and 0.16 mK, at approximately 95% level of confidence), respectively. The extrapolated melting temperature of the segregated sample was supposed to be a closer approximation to the liquidus temperature of tin, whereas the quenched sample yielded the possibility of a misleading extrapolation to the solidus temperature. Therefore, the determination of the liquidus temperature could result in different extrapolated melting temperatures depending on the way the impurities were distributed within the sample, which has implications for the contemporary methodology for realizing temperature fixed points of the International Temperature Scale of 1990 (ITS-90).

The Geology of Yemen: An Annotated Bibliography of Yemen’s Geology, Geography and Earth Science

DTIC Science & Technology

2012-01-01

pneumonia by improving maternal nutrition , health education, promoting breastfeeding, and preventing rickets and nutritional anaemia among the...Monitoring, Modeling, and Management. Merida, Yucatan , Mexico. Bauman, Paul, Sallomy, Janan, Lyness, Lucien, et al. 1996. “The Exploration for a Deep...shopping must also be educated on health and nutrition matters. Due to the traditional segregation of the sexes, this training will have to be

Continuing the Exploration of African Americans in the Early History of Evaluation in the United States: Contributions of Ambrose Caliver in the U.S. Office of Education

ERIC Educational Resources Information Center

Hood, Stafford

2017-01-01

This article, based on the remarks delivered by the author at the Eleanor Chelimsky forum at the Eastern Evaluation Research Society annual conference in 2016, discusses Ambrose Caliver, an evaluator of color who worked for the federal government during segregation. Caliver's history is an important contribution to the evaluation tree. This…

Unresolved attachment and agency in women victims of intimate partner violence: A case-control study.

PubMed

Pallini, Susanna; Alfani, Agnese; Marech, Lucrezia; Laghi, Fiorenzo

2017-06-01

Women victims of IPV are more likely insecurely attached and have experienced childhood abuse, which according to the attachment theory is deeply related to disorganized attachment. This case-control study was performed with the aim to compare the attachment status and the defensive processing patterns of women victims of IPV (cases) with women with no experiences of IPV (controls). Cases were 16 women with an age range from 26 years to 51 years. The control group included 16 women with an age range from 26 years to 59 years. Women's states of mind in regard to attachment were evaluated with the Adult Attachment Projective Picture System, which allows classifying attachment status and defensive mechanisms. Compared with control group, most IPV women resulted having an unresolved attachment status and describing characters less capable to draw upon internal resources, that is, internalized secure base, and less capable to act than controls. Women victims of IPV used significantly more words referring danger and failed protection than controls. The results evidenced the strong effectiveness of the AAP on analysing the psychological attitudes of women victims of IPV. The dramatic events lived by the women victims of IPV are so dominant in their minds that they invade their stories. This could represent a clue of emotional dysregulation. The use of AAP improves the understanding of the agency of self and of the specific levels of trauma experienced by IPV victims, on clarifying their frightening/frightened dynamic, typical of the disorganized attachment relationship, which undermines their activity of mentalization. The therapist will assume the stance of a secure base and then both promoting exploration and contrasting impotence, humiliation, and subordination that IPV women have experienced. This therapeutic interpersonal context will be functional to reach two different but related therapeutic goals: (1) to facilitate the rebuilding of agency (through an activation of subject to explore concrete strategies for exiting from IPV), (2) to explore attachment-related segregated systems from awareness, and to integrate them in memory. © 2016 The British Psychological Society.

Making big communities small: using network science to understand the ecological and behavioral requirements for community social capital.

PubMed

Neal, Zachary

2015-06-01

The concept of social capital is becoming increasingly common in community psychology and elsewhere. However, the multiple conceptual and operational definitions of social capital challenge its utility as a theoretical tool. The goals of this paper are to clarify two forms of social capital (bridging and bonding), explicitly link them to the structural characteristics of small world networks, and explore the behavioral and ecological prerequisites of its formation. First, I use the tools of network science and specifically the concept of small-world networks to clarify what patterns of social relationships are likely to facilitate social capital formation. Second, I use an agent-based model to explore how different ecological characteristics (diversity and segregation) and behavioral tendencies (homophily and proximity) impact communities' potential for developing social capital. The results suggest diverse communities have the greatest potential to develop community social capital, and that segregation moderates the effects that the behavioral tendencies of homophily and proximity have on community social capital. The discussion highlights how these findings provide community-based researchers with both a deeper understanding of the contextual constraints with which they must contend, and a useful tool for targeting their efforts in communities with the greatest need or greatest potential.

Enhancement of SOFC Cathode Electrochemical Performance Using Multi-Phase Interfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morgan, Dane

2015-09-30

This work explored the use of oxide heterostructures for enhancing the catalytic and degradation properties of solid oxide fuel cell (SOFC) cathode electrodes. We focused on heterostructures of Ruddlesden-Popper and perovskite phases. Building on previous work showing enhancement of the Ruddlesden-Popper (La,Sr) 2CoO 4 / perovskite (La,Sr)CoO 3 heterostructure compared to pure (La,Sr)CoO 3 we explored the application of related heterostructures of Ruddlesden-Popper phases on perovskite (La,Sr)(Co,Fe)O 3. Our approaches included thin-film electrodes, physical and electrochemical characterization, elementary reaction kinetics modeling, and ab initio simulations. We demonstrated that Sr segregation to surfaces is likely playing a critical role in themore » performance of (La,Sr)CoO 3 and (La,Sr)(Co,Fe)O 3 and that modification of this Sr segregation may be the mechanism by which Ruddlesden-Popper coatings enhance performances. We determined that (La,Sr)(Co,Fe)O 3 could be enhanced in thin films by about 10× by forming a heterostructure simultaneously with (La,Sr) 2CoO 4 and (La,Sr)CoO 3. We hope that future work will develop this heterostructure for use as a bulk porous electrode.« less

Enlightening discriminative network functional modules behind Principal Component Analysis separation in differential-omic science studies

PubMed Central

Ciucci, Sara; Ge, Yan; Durán, Claudio; Palladini, Alessandra; Jiménez-Jiménez, Víctor; Martínez-Sánchez, Luisa María; Wang, Yuting; Sales, Susanne; Shevchenko, Andrej; Poser, Steven W.; Herbig, Maik; Otto, Oliver; Androutsellis-Theotokis, Andreas; Guck, Jochen; Gerl, Mathias J.; Cannistraci, Carlo Vittorio

2017-01-01

Omic science is rapidly growing and one of the most employed techniques to explore differential patterns in omic datasets is principal component analysis (PCA). However, a method to enlighten the network of omic features that mostly contribute to the sample separation obtained by PCA is missing. An alternative is to build correlation networks between univariately-selected significant omic features, but this neglects the multivariate unsupervised feature compression responsible for the PCA sample segregation. Biologists and medical researchers often prefer effective methods that offer an immediate interpretation to complicated algorithms that in principle promise an improvement but in practice are difficult to be applied and interpreted. Here we present PC-corr: a simple algorithm that associates to any PCA segregation a discriminative network of features. Such network can be inspected in search of functional modules useful in the definition of combinatorial and multiscale biomarkers from multifaceted omic data in systems and precision biomedicine. We offer proofs of PC-corr efficacy on lipidomic, metagenomic, developmental genomic, population genetic, cancer promoteromic and cancer stem-cell mechanomic data. Finally, PC-corr is a general functional network inference approach that can be easily adopted for big data exploration in computer science and analysis of complex systems in physics. PMID:28287094

Meiotic segregation analysis in spermatozoa of pericentric inversion carriers using fluorescence in-situ hybridization.

PubMed

Morel, F; Laudier, B; Guérif, F; Couet, M L; Royère, D; Roux, C; Bresson, J L; Amice, V; De Braekeleer, M; Douet-Guilbert, N

2007-01-01

Pericentric inversions are structural chromosomal abnormalities resulting from two breaks, one on either side of the centromere, within the same chromosome, followed by 180 degrees rotation and reunion of the inverted segment. They can perturb spermatogenesis and lead to the production of unbalanced gametes through the formation of an inversion loop. We report here the analysis of the meiotic segregation in spermatozoa from six pericentric inversion carriers by multicolour fluorescence in-situ hybridization (FISH) and review the literature. The frequencies of the non-recombinant products (inversion or normal chromosomes) were 80% for the inv(20), 91.41% for the inv(12), 99.43% for the inv(2), 68.12% for the inv(1), 97% for the inv(8)(p12q21) and 60.94% for the inv(8)(p12q24.1). The meiotic segregation of 20 pericentric inversions (including ours) is now available. The frequency of unbalanced spermatozoa varies from 0 to 37.85%. The probability of a crossover within the inverted segment is affected by the chromosome and region involved, the length of the inverted segment and the location of the breakpoints. No recombinant chromosomes were produced when the inverted segment involved <30% of the chromosome length (independent of the size of the inverted segment). Between 30 and 50%, few recombinant chromosomes were produced, inducing a slightly increased risk of aneusomy of recombination in the offspring. The risk of aneusomy became very important when the inverted segment was >50% of the chromosome length. Studies on spermatozoa from inversion carriers help in the comprehension of the mechanisms of meiotic segregation. They should be integrated in the genetic exploration of the infertile men to give them a personalized risk assessment of unbalanced spermatozoa.

LES study of the impact of moist thermals on the oxidative capacity of the atmosphere in southern West Africa

NASA Astrophysics Data System (ADS)

Brosse, Fabien; Leriche, Maud; Mari, Céline; Couvreux, Fleur

2018-05-01

The hydroxyl radical (OH) is a highly reactive species and plays a key role in the oxidative capacity of the atmosphere. We explore the potential impact of a convective boundary layer on reconciling the calculation-measurement differences for OH reactivity (the inverse of OH lifetime) attributable to the segregation of OH and its reactants by thermals and the resulting modification of averaged reaction rates. The large-eddy simulation version of the Meso-NH model is used, coupled on-line with a detailed chemistry mechanism to simulate two contrasted biogenic and urban chemical regimes. In both environments, the top of the boundary layer is the region with the highest calculated segregation intensities but with the opposite sign. In the biogenic environment, the inhomogeneous mixing of isoprene and OH leads to a maximum decrease of 30 % of the mean reaction rate in this zone. In the anthropogenic case, the effective rate constant for OH reacting with aldehydes is 16 % higher than the averaged value. OH reactivity is always higher by 15 to 40 % inside thermals in comparison to their surroundings as a function of the chemical environment and time of the day. Since thermals occupy a small fraction of the simulated domain, the impact of turbulent motions on domain-averaged total OH reactivity reaches a maximum decrease of 9 % for the biogenic case and a maximum increase of 5 % for the anthropogenic case. Accounting for the segregation of air masses by turbulent motions in regional and global models may increase OH reactivity in urban environments but lower OH reactivity in biogenic environments. In both cases, segregation alone is insufficient for resolving the underestimation between observed and modeled OH reactivity.

Physical Cause of Kimberlite Occurrences Clustering

NASA Astrophysics Data System (ADS)

Khazan, Y.; Aryasova, O.

2011-12-01

High abundances of incompatible elements in kimberlites are indicative of low or even infinitesimal melting degree in a source. This means that initially protokimberlite melts exist as a system of dispersed small inclusions while the kimberlite transportation to the surface assumes formation of macroscopic melt pools. In other words, an inevitable stage of the protokimberlite melt evolution is its segregation from the porous matrix inside a partially molten zone and accumulation to the zone top where the melt fraction greatly exceeds the initial melting degree. Khazan (2010), Khazan, Aryasova (2011) demonstrated that the characteristic segregation time, τ, depends on the ratio L/δ of the molten zone thickness, L, to the compaction length, δ, (McKenzie, 1984), which in its turn is defined by melt and matrix viscosities and matrix permeability. For low-viscosity melts the segregation time decreases with increasing molten zone thickness as τ≈19.5(η/ΔρgL) (η is the matrix viscosity, Δρ is the density contrast) and is independent of poorly known melt viscosity, matrix permeability, and melting degree. Since no system can exist longer than its decay time is, the decreasing segregation time dependence on the molten zone thickness constrains the latter. To illustrate, assume that the melting is due to decompression and accompanies ascent of a mantle diapir with a velocity V. In this case the molten zone thickness increases linearly with time L=Vt where t is measured from the onset of melting and cannot exceed the segregation time, so that t≤τ (Fig. 1) and L≤L*=4.4(Vη/Δρg)^0.5. Under a robust parameter choice (η=10^19 Pa s, Δρ=300 kg/m^3, V=3 cm/year) L* is about 8 km, with the corresponding segregation time τ being of 0.3 Myear (Fig. 1). After the first segregation, a new partially molten zone grows resulting in the next segregation when its thickness reaches the maximum possible value L*. This sequence of events repeats until the whole diapir passes by the melting level. One may estimate a diapir diameter D of 30 to 80 km based upon a size of low-amplitude uplifts associated with the kimberlite fields (e. g., Kaminsky et al., 1995). So the diapir ascent results in a cluster of ~D/L*=3-10 same age and composition eruptions. A total activity accociated with the cluster continues of τD/L*=1 to 3 Myear as it is really observed (Heaman et al.,2004). The described sequence of events is schematic(lly illustrated in Fig. 2. Heaman L et al., Lithos, 2004, 76, 377. Kaminsky F et al., J. Geochem. Explor. 1995, 53, 167. Khazan Y, Geoph. J. Int. 2010, 183, 601. Khazan Y, Aryasona O, Izvestiya, Phys. Solid Earth. 2011, 47, No. 5, 425. McKenzie D, J Petrol. 1984, 25, 713.

Overcoming Triple Segregation

ERIC Educational Resources Information Center

Gandara, Patricia

2010-01-01

Latinos are, after whites, the most segregated student group in the United States, and their segregation is closely tied to poor academic outcomes. Latinos experience a triple segregation: by race/ethnicity, poverty, and language. Racial segregation perpetuates negative stereotypes, reduces the likelihood of a strong teaching staff, and is often…

Capturing the Two Dimensions of Residential Segregation at the Neighborhood Level for Health Research

PubMed Central

Oka, Masayoshi; Wong, David W. S.

2014-01-01

Two conceptual and methodological foundations of segregation studies are that (i) segregation involves more than one group, and (ii) segregation measures need to quantify how different population groups are distributed across space. Therefore, percentage of population belonging to a group is not an appropriate measure of segregation because it does not describe how populations are spread across different areal units or neighborhoods. In principle, evenness and isolation are the two distinct dimensions of segregation that capture the spatial patterns of population groups. To portray people’s daily environment more accurately, segregation measures need to account for the spatial relationships between areal units and to reflect the situations at the neighborhood scale. For these reasons, the use of local spatial entropy-based diversity index (SHi) and local spatial isolation index (Si) to capture the evenness and isolation dimensions of segregation, respectively, are preferable. However, these two local spatial segregation indexes have rarely been incorporated into health research. Rather ineffective and insufficient segregation measures have been used in previous studies. Hence, this paper empirically demonstrates how the two measures can reflect the two distinct dimensions of segregation at the neighborhood level, and argues conceptually and set the stage for their future use to effectively and meaningfully examine the relationships between residential segregation and health. PMID:25202687

Residential segregation, dividing walls and mental health: a population-based record linkage study.

PubMed

Maguire, Aideen; French, Declan; O'Reilly, Dermot

2016-09-01

Neighbourhood segregation has been described as a fundamental determinant of physical health, but literature on its effect on mental health is less clear. While most previous research has relied on conceptualised measures of segregation, Northern Ireland is unique as it contains physical manifestations of segregation in the form of segregation barriers (or 'peacelines') which can be used to accurately identify residential segregation. We used population-wide health record data on over 1.3 million individuals, to analyse the effect of residential segregation, measured by both the formal Dissimilarity Index and by proximity to a segregation barrier, on the likelihood of poor mental health. Using multilevel logistic regression models, we found residential segregation measured by the Dissimilarity Index poses no additional risk to the likelihood of poor mental health after adjustment for area-level deprivation. However, residence in an area segregated by a 'peaceline' increases the likelihood of antidepressant medication by 19% (OR=1.19, 95% CI 1.14 to 1.23) and anxiolytic medication by 39% (OR=1.39, 95% CI 1.32 to 1.48), even after adjustment for gender, age, conurbation, deprivation and crime. Living in an area segregated by a 'peaceline' is detrimental to mental health suggesting segregated areas characterised by a heightened sense of 'other' pose a greater risk to mental health. The difference in results based on segregation measure highlights the importance of choice of measure when studying segregation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

The Role of Residential Segregation in Contemporary School Segregation

ERIC Educational Resources Information Center

Frankenberg, Erica

2013-01-01

Inaction to address housing segregation in metropolitan areas has resulted in persistently high levels of residential segregation. As the Supreme Court has recently limited school districts' voluntary integration efforts, this article considers the role of residential segregation in maintaining racially isolated schools, namely what is known about…

41 CFR 109-1.5106 - Segregation of personal property.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Segregation of personal...-INTRODUCTION 1.51-Personal Property Management Standards and Practices § 109-1.5106 Segregation of personal...) The segregation of the property would materially hinder the progress of the work (i.e., segregation is...

49 CFR 176.146 - Segregation from non-hazardous materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Segregation from non-hazardous materials. 176.146... VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.146 Segregation from non... for “away from” segregation apply. (2) An explosive substance or article which has a secondary...

49 CFR 176.140 - Segregation from other classes of hazardous materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Segregation from other classes of hazardous... CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.140 Segregation from other classes of hazardous materials. (a) Class 1 (explosive) materials must be segregated...

41 CFR 109-1.5106 - Segregation of personal property.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Segregation of personal...-INTRODUCTION 1.51-Personal Property Management Standards and Practices § 109-1.5106 Segregation of personal...) The segregation of the property would materially hinder the progress of the work (i.e., segregation is...

Income Segregation between Schools and School Districts

ERIC Educational Resources Information Center

Owens, Ann; Reardon, Sean F.; Jencks, Christopher

2016-01-01

Although trends in the racial segregation of schools are well documented, less is known about trends in income segregation. We use multiple data sources to document trends in income segregation between schools and school districts. Between-district income segregation of families with children enrolled in public school increased by over 15% from…

49 CFR 176.144 - Segregation of Class 1 (explosive) materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation of Class 1 (explosive) materials. 176... VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.144 Segregation of Class... any ferrous metal or aluminum alloy, unless separated by a partition. (e) Segregation on deck: When...

49 CFR 176.144 - Segregation of Class 1 (explosive) materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Segregation of Class 1 (explosive) materials. 176... VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.144 Segregation of Class... any ferrous metal or aluminum alloy, unless separated by a partition. (e) Segregation on deck: When...

49 CFR 176.146 - Segregation from non-hazardous materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation from non-hazardous materials. 176.146... VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.146 Segregation from non... for “away from” segregation apply. (2) An explosive substance or article which has a secondary...

49 CFR 176.140 - Segregation from other classes of hazardous materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation from other classes of hazardous... CARRIAGE BY VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.140 Segregation from other classes of hazardous materials. (a) Class 1 (explosive) materials must be segregated...

46 CFR 148.120 - Stowage and segregation requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation requirements. 148.120 Section... OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.120 Stowage and segregation requirements. (a) Each material listed in Table 148.10 of this part must be segregated from...

Shaping Income Segregation in Schools: The Role of School Attendance Zone Geography

ERIC Educational Resources Information Center

Saporito, Salvatore

2017-01-01

This study investigates how much the geographic shapes of school attendance zones contributes to their levels of income segregation while holding constant levels of income segregation across residential areas. Income segregation across attendance zones is measured with the rank ordered information theory index. Income segregation across…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenik, E.A.

X-ray microanalysis in an analytical electron microscope is a proven technique for the measurement of solute segregation in alloys. Solute segregation under equilibrium or nonequilibrium conditions can strongly influence material performance. X-ray microanalysis in an analytical electron microscope provides an alternative technique to measure grain boundary segregation, as well as segregation to other defects not accessible to Auger analysis. The utility of the technique is demonstrated by measurements of equilibrium segregation to boundaries in an antimony containing stainless steel, including the variation of segregation with boundary character and by measurements of nonequilibrium segregation to boundaries and dislocations in an ion-irradiatedmore » stainless steel.« less

Segregation effects during solidification in weightless melts

NASA Technical Reports Server (NTRS)

Li, C.

1973-01-01

Two types of melt segregation effects were studied: (1) evaporative segregation, or segregation due to surface evaporation; and (2) freezing segregation, or segregation due to liquid-solid phase transformation. These segregation effects are closely related. In fact, evaporative segregation always precedes freezing segregation to some degree and must often be studied prior to performing meaningful solidification experiments. This is particularly true since evaporation may cause the melt composition, at least at the critical surface regions or layers to be affected manyfold within seconds so that the surface region or layer melting point and other thermophysical properties, nucleation characteristics, base for undercooling, and critical velocity to avoid constitutional supercooling, may be completely unexpected. An important objective was, therefore, to develop the necessary normal evaporation equations for predicting the compositional changes within specified times at temperature and to correlate these equations with actual experimental data collected from the literature.

Molecular- and Domain-level Microstructure-dependent Material Model for Nano-segregated Polyurea

DTIC Science & Technology

2013-04-15

material subroutine VUMAT of ABAQUS /Explicit (Dassault Systems, 2010), a commercial finite element code. This subroutine is called by the ABAQUS solver...rate of change of the local internal thermal energy is equal to the corresponding rate of dissipative work. Critical assessment of this model identified...The model also takes into account the plastic expansion or contraction of voids and therefore the stresses are appropriately modified to account for

Ice Segregation and Frost Heaving.

DTIC Science & Technology

1984-01-01

to a buried chilled gas pipeline by continual frost ’. ’- heave during the service life or to a buried liquefied gas tank is a more _ recent concern...M). Lule en: Uiversity of Lulea. Pehner, E., 1982. Aspects of ice lens fornmation. P ing of the Third International Syvosium on Ground Freezi, Hanover...Soils. Lalea, Sweden: Uiversity ofLulea. . Berg, R. L., G. Guymon and J. Ingersoll, 1979. Conference on soil-water . problems in cold regions. Cold

Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography

NASA Astrophysics Data System (ADS)

Bae, Chang-Jun

Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to prevent segregation, and sintering and cristobalite transformation in fused silica compacts.

Latino residential segregation and self-rated health among Latinos: Washington State Behavioral Risk Factor Surveillance System, 2012–2014

PubMed Central

Plascak, Jesse J.; Molina, Yamile; Wu-Georges, Samantha; Idris, Ayah; Thompson, Beti

2016-01-01

The relationship between Latino residential segregation and self-rated health (SRH) is unclear, but might be partially affected by social capital. We investigated the association between Latino residential segregation and SRH while also examining the roles of various social capital measures. Washington State Behavioral Risk Factor Surveillance System (2012–2014) and U.S. Census data were linked by zip code and zip code tabulation area. Multilevel logistic regression models were used to estimate odds of good or better SRH by Latino residential segregation, measured by the Gini coefficient, and controlling for sociodemographic, acculturation and social capital measures of neighborhood ties, collective socialization of children, and social control. The Latino residential segregation – SRH relationship was convex, or ‘U’-shaped, such that increases in segregation among Latinos residing in lower segregation areas was associated with lower SRH while increases in segregation among Latinos residing in higher segregation areas was associated with higher SRH. The social capital measures were independently associated with SRH but had little effect on the relationship between Latino residential segregation and SRH. A convex relationship between Latino residential segregation and SRH could explain mixed findings of previous studies. Although important for SRH, social capital measures of neighborhood ties, collective socialization of children, and social control might not account for the relationship between Latino residential segregation and SRH. PMID:27173739

Latino residential segregation and self-rated health among Latinos: Washington State Behavioral Risk Factor Surveillance System, 2012-2014.

PubMed

Plascak, Jesse J; Molina, Yamile; Wu-Georges, Samantha; Idris, Ayah; Thompson, Beti

2016-06-01

The relationship between Latino residential segregation and self-rated health (SRH) is unclear, but might be partially affected by social capital. We investigated the association between Latino residential segregation and SRH while also examining the roles of various social capital measures. Washington State Behavioral Risk Factor Surveillance System (2012-2014) and U.S. Census data were linked by zip code and zip code tabulation area. Multilevel logistic regression models were used to estimate odds of good or better SRH by Latino residential segregation, measured by the Gini coefficient, and controlling for sociodemographic, acculturation and social capital measures of neighborhood ties, collective socialization of children, and social control. The Latino residential segregation - SRH relationship was convex, or 'U'-shaped, such that increases in segregation among Latinos residing in lower segregation areas was associated with lower SRH while increases in segregation among Latinos residing in higher segregation areas was associated with higher SRH. The social capital measures were independently associated with SRH but had little effect on the relationship between Latino residential segregation and SRH. A convex relationship between Latino residential segregation and SRH could explain mixed findings of previous studies. Although important for SRH, social capital measures of neighborhood ties, collective socialization of children, and social control might not account for the relationship between Latino residential segregation and SRH. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Revaluation of Indexes of Residential Segregation

ERIC Educational Resources Information Center

Winship, Christopher

1977-01-01

Shows that there are at least two different perspectives from which residential segregation can be examined. Segregation can be measured as it deviates from a situation of complete desegregation or in terms of a situation in which there is random segregation in the city. New criteria for indexes of residential segregation are developed. (Author/JM)

28 CFR 541.20 - Justification for placement in disciplinary segregation and review of inmates in disciplinary...

Code of Federal Regulations, 2010 CFR

2010-07-01

... disciplinary segregation and review of inmates in disciplinary segregation. 541.20 Section 541.20 Judicial... disciplinary segregation and review of inmates in disciplinary segregation. (a) Except as provided in paragraph... the physical confines of administrative detention, and (3) upon advice of appropriate medical staff...

43 CFR 3873.1 - Segregation of mineral from non-mineral land.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation of mineral from non-mineral... AND CONFLICTS Segregation § 3873.1 Segregation of mineral from non-mineral land. Where a survey is... satisfactorily established that there are existent prior unpatented mining claims, the segregation of the latter...

Income Segregation between Schools and School Districts. CEPA Working Paper No. 16-04

ERIC Educational Resources Information Center

Owens, Ann; Reardon, Sean F.; Jencks, Christopher

2016-01-01

Although trends in the racial segregation of schools are well documented, less is known about trends in "income" segregation. We use multiple data sources to document trends in income segregation between schools and school districts. Between-district income segregation of families with children enrolled in public school increased by over…

Segregation as Splitting, Segregation as Joining: Schools, Housing, and the Many Modes of Jim Crow

ERIC Educational Resources Information Center

Highsmith, Andrew R.; Erickson, Ansley T.

2015-01-01

Popular understandings of segregation often emphasize the Jim Crow South before the 1954 "Brown" decision and, in many instances, explain continued segregation in schooling as the result of segregated housing patterns. The case of Flint, Michigan, complicates these views, at once illustrating the depth of governmental commitment to…

A Naturalistic Observational Study of Informal Segregation: Seating Patterns in Lectures

ERIC Educational Resources Information Center

Koen, Jennifer; Durrheim, Kevin

2010-01-01

In spite of the removal of legislated racial segregation, a number of observational studies in South Africa and elsewhere have shown that "informal," nonlegislated segregation persists in spaces of everyday interaction. Most of these have been case studies of segregation at single sites. The authors seek to quantify segregation in a…

Multi-Contextual Segregation and Environmental Justice Research: Toward Fine-Scale Spatiotemporal Approaches.

PubMed

Park, Yoo Min; Kwan, Mei-Po

2017-10-10

Many environmental justice studies have sought to examine the effect of residential segregation on unequal exposure to environmental factors among different social groups, but little is known about how segregation in non-residential contexts affects such disparity. Based on a review of the relevant literature, this paper discusses the limitations of traditional residence-based approaches in examining the association between socioeconomic or racial/ethnic segregation and unequal environmental exposure in environmental justice research. It emphasizes that future research needs to go beyond residential segregation by considering the full spectrum of segregation experienced by people in various geographic and temporal contexts of everyday life. Along with this comprehensive understanding of segregation, the paper also highlights the importance of assessing environmental exposure at a high spatiotemporal resolution in environmental justice research. The successful integration of a comprehensive concept of segregation, high-resolution data and fine-grained spatiotemporal approaches to assessing segregation and environmental exposure would provide more nuanced and robust findings on the associations between segregation and disparities in environmental exposure and their health impacts. Moreover, it would also contribute to significantly expanding the scope of environmental justice research.

Luminosity segregation in galaxy clusters as an indication of dynamical evolution

NASA Technical Reports Server (NTRS)

Baier, F. W.; Schmidt, K.-H.

1993-01-01

Theoretical models describing the dynamical evolution of self-gravitating systems predict a spatial mass segregation for more evolved systems, with the more massive objects concentrated toward the center of the configuration. From the observational point of view, however, the existence of mass segregation in galaxy clusters seems to be a matter of controversy. A special problem in this connection is the formation of cD galaxies in the centers of galaxy clusters. The most promising scenarios of their formation are galaxy cannibalism (merger scenario) and growing by cooling flows. It seems to be plausible to consider the swallowing of smaller systems by a dominant galaxy as an important process in the evolution of a cD galaxy. The stage of the evolution of the dominant galaxy should be reflected by the surrounding galaxy population, especially by possible mass segregation effects. Assuming that mass segregation is tantamount to luminosity segregation we analyzed luminosity segregation in roughly 40 cD galaxy clusters. Obviously there are three different groups of clusters: (1) clusters with luminosity segregation, (2) clusters without luminosity segregation, and (3) such objects exhibiting a phenomenon which we call antisegregation in luminosity, i.e. a deficiency of bright galaxies in the central regions of clusters. This result is interpreted in the sense of different degrees of mass segregation and as an indication for different evolution stages of these clusters. The clusters are arranged in the three segregation classes 2, 1, and 0 (S2 = strong mass segregation, S1 = moderate mass segregation, S0 = weak or absent mass segregation). We assume that a galaxy cluster starts its dynamical evolution after virialization without any radial mass segregation. Energy exchange during encounters of cluster members as well as merger processes between cluster galaxies lead to an increasing radial mass segregation in the cluster (S1). If a certain degree of segregation (S2) has been established, an essential number of slow-moving and relative massive cluster members in the center will be cannibalized by the initial brightest cluster galaxy. This process should lead to the growing of the predominate galaxy, which is accompanied by a diminution of the mass segregation (transition to S1 and S0, respectively) in the neighborhood of the central very massive galaxy. An increase of the areal density of brighter galaxies towards the outer cluster regions (antisegregation of luminosity), i.e. an extreme low degree of mass segregation was estimated for a substantial percentage of cD clusters. This result favors the cannibalism scenario for the formation of cD galaxies.

Black-white metropolitan segregation and self-rated health: Investigating the role of neighborhood poverty.

PubMed

Do, D Phuong; Frank, Reanne; Iceland, John

2017-08-01

While black-white segregation has been consistently linked to detrimental health outcomes for blacks, whether segregation is necessarily a zero-sum arrangement in which some groups accrue health advantages at the expense of other groups and whether metropolitan segregation impacts the health of racial groups uniformly within the metropolitan area, remains unclear. Using nationally representative data from the 2008-2013 National Health Interview Survey linked to Census data, we investigate whether the association between metropolitan segregation and health is invariant within the metropolitan area or whether it is modified by neighborhood poverty for black and white Americans. In doing so, we assess the extent to which segregation involves direct health tradeoffs between blacks and whites. We conduct race-stratified multinomial and logistic regression models to assess the relationship between 1) segregation and level of neighborhood poverty and 2) segregation, neighborhood poverty, and poor health, respectively. We find that, for blacks, segregation was associated with a higher likelihood of residing in high poverty neighborhoods, net of individual-level socioeconomic characteristics. Segregation was positively associated with poor health for blacks in high poverty neighborhoods, but not for those in lower poverty neighborhoods. Hence, the self-rated health of blacks clearly suffers as a result of black-white segregation - both directly, and indirectly through exposure to high poverty neighborhoods. We do not find consistent evidence for a direct relationship between segregation and poor health for whites. However, we find some suggestive evidence that segregation may indirectly benefit whites through decreasing their exposure to high poverty environments. These findings underscore the critical role of concentrated disadvantage in the complex interconnection between metropolitan segregation and health. Weakening the link between racial segregation and concentrated poverty via local policy and planning has the potential for broad population-based health improvements and significant reductions in black-white health disparities. Copyright © 2017. Published by Elsevier Ltd.

The joy of six: how to control your crossovers.

PubMed

Globus, Samuel T; Keeney, Scott

2012-03-30

Meiotic cells tightly regulate the number and distribution of crossovers to promote accurate chromosome segregation. Yokoo and colleagues uncover a metazoan-specific, cyclin-like protein that is crucial for crossover formation. They utilize this protein's unique properties to explore a remarkable example of biological numerology, whereby nearly every meiotic cell in C. elegans makes precisely six crossovers, one for each of its six chromosome pairs. Copyright © 2012 Elsevier Inc. All rights reserved.

Public school segregation and juvenile violent crime arrests in metropolitan areas.

PubMed

Eitle, David; Eitle, Tamela McNulty

2010-01-01

Previous research has established an association between residential segregation and violent crime in urban America. Our study examines whether school-based segregation is predictive of arrests of juveniles for violent crimes in U.S. metro areas. Using Census, Uniform Crime Report, and Common Core data for 204 metro areas, a measure of school-based racial segregation, Theil's entropy index, is decomposed into two components: between- and within-district segregation. Findings reveal evidence of a significant interaction term: Within-district segregation is inversely associated with arrests for juvenile violence, but only in metropolitan areas with higher than average levels of between-district segregation.

Exploring the variability of aerosol particle composition in the Arctic: a study from the springtime ACCACIA campaign

NASA Astrophysics Data System (ADS)

Young, G.; Jones, H. M.; Darbyshire, E.; Baustian, K. J.; McQuaid, J. B.; Bower, K. N.; Connolly, P. J.; Gallagher, M. W.; Choularton, T. W.

2015-10-01

Single-particle compositional analysis of filter samples collected on-board the FAAM BAe-146 aircraft is presented for six flights during the springtime Aerosol-Cloud Coupling and Climate Interactions in the Arctic (ACCACIA) campaign (March-April 2013). Scanning electron microscopy was utilised to derive size distributions and size-segregated particle compositions. These data were compared to corresponding data from wing-mounted optical particle counters and reasonable agreement between the calculated number size distributions was found. Significant variability in composition was observed, with differing external and internal mixing identified, between air mass trajectory cases based on HYSPLIT analyses. Dominant particle classes were silicate-based dusts and sea salts, with particles notably rich in K and Ca detected in one case. Source regions varied from the Arctic Ocean and Greenland through to northern Russia and the European continent. Good agreement between the back trajectories was mirrored by comparable compositional trends between samples. Silicate dusts were identified in all cases, and the elemental composition of the dust was consistent for all samples except one. It is hypothesised that long-range, high-altitude transport was primarily responsible for this dust, with likely sources including the Asian arid regions.

The concept of governance in dual-use research.

PubMed

Dubov, Alex

2014-08-01

The rapid advance of life science within the context of increased international concern over the potential misuse of findings has resulted in the lack of agreement on the issues of responsibility, control and collaboration. This progress of knowledge outpaces the efforts of creating moral and legal guidelines for the detection and minimization of the risks in the research process. There is a need to identify and address normative aspects of dual-use research. This paper focuses on the issues of safety and global collaboration in life science research by highlighting the importance of openness, enabling policies and cooperative governance. These safeguards are believed to reduce the risks related to the misuse of science while enabling the important research to move forward. The paper addresses the need for a better definition of dual use concept and, based on the historical precedents, explores the moral concerns and governmental strategies of dual-use research. The three necessary moves in addressing the issue of security in life sciences are suggested: the move from constraining to enabling types of policies, the move from secrecy to openness, and the move from segregation to integration of the public voice.

ISS Ambient Air Quality: Updated Inventory of Known Aerosol Sources

NASA Technical Reports Server (NTRS)

Meyer, Marit

2014-01-01

Spacecraft cabin air quality is of fundamental importance to crew health, with concerns encompassing both gaseous contaminants and particulate matter. Little opportunity exists for direct measurement of aerosol concentrations on the International Space Station (ISS), however, an aerosol source model was developed for the purpose of filtration and ventilation systems design. This model has successfully been applied, however, since the initial effort, an increase in the number of crewmembers from 3 to 6 and new processes on board the ISS necessitate an updated aerosol inventory to accurately reflect the current ambient aerosol conditions. Results from recent analyses of dust samples from ISS, combined with a literature review provide new predicted aerosol emission rates in terms of size-segregated mass and number concentration. Some new aerosol sources have been considered and added to the existing array of materials. The goal of this work is to provide updated filtration model inputs which can verify that the current ISS filtration system is adequate and filter lifetime targets are met. This inventory of aerosol sources is applicable to other spacecraft, and becomes more important as NASA considers future long term exploration missions, which will preclude the opportunity for resupply of filtration products.

Lateral organization of biological membranes: role of long-range interactions.

PubMed

Duneau, Jean-Pierre; Sturgis, James N

2013-12-01

The lateral organization of biological membranes is of great importance in many biological processes, both for the formation of specific structures such as super-complexes and for function as observed in signal transduction systems. Over the last years, AFM studies, particularly of bacterial photosynthetic membranes, have revealed that certain proteins are able to segregate into functional domains with a specific organization. Furthermore, the extended non-random nature of the organization has been suggested to be important for the energy and redox transport properties of these specialized membranes. In the work reported here, using a coarse-grained Monte Carlo approach, we have investigated the nature of interaction potentials able to drive the formation and segregation of specialized membrane domains from the rest of the membrane and furthermore how the internal organization of the segregated domains can be modulated by the interaction potentials. These simulations show that long-range interactions are necessary to allow formation of membrane domains of realistic structure. We suggest that such possibly non-specific interactions may be of great importance in the lateral organization of biological membranes in general and in photosynthetic systems in particular. Finally, we consider the possible molecular origins of such interactions and suggest a fundamental role for lipid-mediated interactions in driving the formation of specialized photosynthetic membrane domains. We call these lipid-mediated interactions a 'lipophobic effect.'

From calling to a scheduled vocation: Swedish male and female students' reflections on being a doctor.

PubMed

Johansson, Eva E; Hamberg, Katarina

2007-02-01

All over the world an increasing number of women are entering medical schools. Soon women will constitute half of the physician workforce in Scandinavia. However, specialty segregation persists. Reports have shown different motives among male and female doctors to be, but the impact of gender, i.e. how ongoing social constructions of femininity and masculinity influence the development of professionalism, is not fully described. The purpose of this study was to explore views and visions among second-year students at a Swedish Medical School, and to identify challenges for education and workforce planning. After receiving research ethics board approval, all students participating in the course 'Professional development', including a task to write a free-text essay on the theme 'to be a doctor', were invited to share their essays for analysis. Of 138 (40% men) students in 2002, 104 (39% men) accepted. The texts were analysed according to grounded theory. Students held 'doctorship' to be an outstanding profession of commitment, authority and duty. Fears were exposed, especially among women, regarding how to fit demands of self-sacrifices and balancing a private life. Belonging to a new generation, they conceived gender equity as self-evident. Actual working conditions were met with disapproval, as did an all-embracing calling. A scheduled vocation was hoped for. They relied on the mass of women to implement change. Women's 'other' values, alluding to family orientation, were expected to alter working conditions and also give men more leisure time. Despite equity conviction, segregating gender patterns in students' representations, interactions with tutors and future prospects were disclosed. Students' arguments raise challenges for medical educators and planners regarding professional values, medical socialization and specialty recruitment. The new generation requires a renewed Hippocratic Oath, gender-aware role models and practice sites. Swedish students' arguments are compared with current international literature.

Structural analysis of nickel doped cerium oxide catalysts for fuel reforming in solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Cavendish, Rio

As world energy demands increase, research into more efficient energy production methods has become imperative. Heterogeneous catalysis and nanoscience are used to promote chemical transformations important for energy production. These concepts are important in solid oxide fuel cells (SOFCs) which have attracted attention because of their potential to provide an efficient and environmentally favorable power generation system. The SOFC is also fuel-flexible with the ability to run directly on many fuels other than hydrogen. Internal fuel reforming directly in the anode of the SOFC would greatly reduce the cost and complexity of the device. Methane is the simplest hydrocarbon and a main component in natural gas, making it useful when testing catalysts on the laboratory scale. Nickel (Ni) and gadolinium (Gd) doped ceria (CeO 2) catalysts for potential use in the SOFC anode were synthesized with a spray drying method and tested for catalytic performance using partial oxidation of methane and steam reforming. The relationships between catalytic performance and structure were then investigated using X-ray diffraction, transmission electron microscopy, and environmental transmission electron microscopy. The possibility of solid solutions, segregated phases, and surface layers of Ni were explored. Results for a 10 at.% Ni in CeO2 catalyst reveal a poor catalytic behavior while a 20 at.% Ni in CeO2 catalyst is shown to have superior activity. The inclusion of both 10 at.% Gd and 10 at.% Ni in CeO2 enhances the catalytic performance. Analysis of the presence of Ni in all 3 samples reveals Ni heterogeneity and little evidence for extensive solid solution doping. Ni is found in small domains throughout CeO2 particles. In the 20 at.% Ni sample a segregated, catalytically active NiO phase is observed. Overall, it is found that significant interaction between Ni and CeO2 occurs that could affect the synthesis and functionality of the SOFC anode.

Influence of the "surface effect" on the segregation parameters of S in Fe(100): A multi-scale modelling and Auger Electron Spectroscopy study

NASA Astrophysics Data System (ADS)

Barnard, P. E.; Terblans, J. J.; Swart, H. C.

2015-12-01

The article takes a new look at the process of atomic segregation by considering the influence of surface relaxation on the segregation parameters; the activation energy (Q), segregation energy (ΔG), interaction parameter (Ω) and the pre-exponential factor (D0). Computational modelling, namely Density Functional Theory (DFT) and the Modified Darken Model (MDM) in conjunction with Auger Electron Spectroscopy (AES) was utilized to study the variation of the segregation parameters for S in the surface region of Fe(100). Results indicate a variation in each of the segregation parameters as a function of the atomic layer under consideration. Values of the segregation parameters varied more dramatically as the surface layer is approached, with atomic layer 2 having the largest deviations in comparison to the bulk values. This atomic layer had the highest Q value and formed the rate limiting step for the segregation of S towards the Fe(100) surface. It was found that the segregation process is influenced by two sets of segregation parameters, those of the surface region formed by atomic layer 2, and those in the bulk material. This article is the first to conduct a full scale investigation on the influence of surface relaxation on segregation and labelled it the "surface effect".

Gender Segregation in the Spanish Labor Market: An Alternative Approach

ERIC Educational Resources Information Center

del Rio, Coral; Alonso-Villar, Olga

2010-01-01

The aim of this paper is to study occupational segregation by gender in Spain, which is a country where occupational segregation explains a large part of the gender wage gap. As opposed to previous studies, this paper measures not only overall segregation, but also the segregation of several population subgroups. For this purpose, this paper uses…

The Growth of Segregation in American Schools: Changing Patterns of Separation and Poverty since 1968.

ERIC Educational Resources Information Center

Orfield, Gary; And Others

This study shows where school segregation is concentrated and where schools remain highly integrated. It offers the first national comparison of segregation by community size and reveals that segregation remains high in big cities and serious in mid-size central cities. Many African-American and Latino students also attend segregated schools in…

Residential segregation and racial disparities in self-rated health: How do dimensions of residential segregation matter?1

PubMed Central

Yang, Tse-Chuan; Zhao, Yunhan; Song, Qian

2016-01-01

Previous research on segregation and health has been criticized for overlooking the fact that segregation is a multi-dimensional concept (i.e., evenness, exposure, concentration, centralization, and clustering) and recent evidence drawn from non-black minorities challenges the conventional belief that residential segregation widens racial health disparities. Combining a survey data (n=18,752) from Philadelphia with the 2010 Census tract (n=925) data, we examine two theoretical frameworks to understand why the association of segregation with health may differ by race/ethnicity. Specifically, we investigate how each dimension of segregation contributed to racial disparities in self-rated health. We found (1) high levels of white/ black concentration could exacerbate the white/black health disparities up to 25 percent, (2) the white/Hispanic health disparities was narrowed by increasing the level of white/Hispanic centralization, and (3) no single dimension of segregation statistically outperforms others. Our findings supported that segregation is bad for blacks but may be beneficial for Hispanics. PMID:27886735

Micro and Macro Segregation in Alloys Solidifying with Equiaxed Morphology

NASA Technical Reports Server (NTRS)

Stefanescu, Doru M.; Curreri, Peter A.; Leon-Torres, Jose; Sen, Subhayu

1996-01-01

To understand macro segregation formation in Al-Cu alloys, experiments were run under terrestrial gravity (1g) and under low gravity during parabolic flights (10(exp -2) g). Alloys of two different compositions (2% and 5% Cu) were solidified at two different cooling rates. Systematic microscopic and SEM observations produced microstructural and segregation maps for all samples. These maps may be used as benchmark experiments for validation of microstructure evolution and segregation models. As expected, the macro segregation maps are very complex. When segregation was measured along the central axis of the sample, the highest macro segregation for samples solidified at 1g was obtained for the lowest cooling rate. This behavior is attributed to the longer time available for natural convection and shrinkage flow to affect solute redistribution. In samples solidified under low-g, the highest macro-segregation was obtained at the highest cooling rate. In general, low-gravity solidification resulted in less segregation. To explain the experimental findings, an analytical (Flemings-Nereo) and a numerical model were used. For the numerical model, the continuum formulation was employed to describe the macroscopic transports of mass, energy, and momentum, associated with the microscopic transport phenomena, for a two-phase system. The model proposed considers that liquid flow is driven by thermal and solutal buoyancy, and by solidification shrinkage. The Flemings-Nereo model explains well macro segregation in the initial stages of low-gravity segregation. The numerical model can describe the complex macro segregation pattern and the differences between low- and high-gravity solidification.

Two critical periods in early visual cortex during figure-ground segregation.

PubMed

Wokke, Martijn E; Sligte, Ilja G; Steven Scholte, H; Lamme, Victor A F

2012-11-01

The ability to distinguish a figure from its background is crucial for visual perception. To date, it remains unresolved where and how in the visual system different stages of figure-ground segregation emerge. Neural correlates of figure border detection have consistently been found in early visual cortex (V1/V2). However, areas V1/V2 have also been frequently associated with later stages of figure-ground segregation (such as border ownership or surface segregation). To causally link activity in early visual cortex to different stages of figure-ground segregation, we briefly disrupted activity in areas V1/V2 at various moments in time using transcranial magnetic stimulation (TMS). Prior to stimulation we presented stimuli that made it possible to differentiate between figure border detection and surface segregation. We concurrently recorded electroencephalographic (EEG) signals to examine how neural correlates of figure-ground segregation were affected by TMS. Results show that disruption of V1/V2 in an early time window (96-119 msec) affected detection of figure stimuli and affected neural correlates of figure border detection, border ownership, and surface segregation. TMS applied in a relatively late time window (236-259 msec) selectively deteriorated performance associated with surface segregation. We conclude that areas V1/V2 are not only essential in an early stage of figure-ground segregation when figure borders are detected, but subsequently causally contribute to more sophisticated stages of figure-ground segregation such as surface segregation.

Two critical periods in early visual cortex during figure–ground segregation

PubMed Central

Wokke, Martijn E; Sligte, Ilja G; Steven Scholte, H; Lamme, Victor A F

2012-01-01

The ability to distinguish a figure from its background is crucial for visual perception. To date, it remains unresolved where and how in the visual system different stages of figure–ground segregation emerge. Neural correlates of figure border detection have consistently been found in early visual cortex (V1/V2). However, areas V1/V2 have also been frequently associated with later stages of figure–ground segregation (such as border ownership or surface segregation). To causally link activity in early visual cortex to different stages of figure–ground segregation, we briefly disrupted activity in areas V1/V2 at various moments in time using transcranial magnetic stimulation (TMS). Prior to stimulation we presented stimuli that made it possible to differentiate between figure border detection and surface segregation. We concurrently recorded electroencephalographic (EEG) signals to examine how neural correlates of figure–ground segregation were affected by TMS. Results show that disruption of V1/V2 in an early time window (96–119 msec) affected detection of figure stimuli and affected neural correlates of figure border detection, border ownership, and surface segregation. TMS applied in a relatively late time window (236–259 msec) selectively deteriorated performance associated with surface segregation. We conclude that areas V1/V2 are not only essential in an early stage of figure–ground segregation when figure borders are detected, but subsequently causally contribute to more sophisticated stages of figure–ground segregation such as surface segregation. PMID:23170239

[Urban dynamics in the decade of the 1980s: concentration of in-migration, spatial segregation and social exclusion].

PubMed

Contreras, A M

1991-01-01

The effects of 2 basic socioeconomic processes of the 1980s on urban dynamics in the Dominican Republic are described. The 2 processes were the restructuring of the national productive apparatus following anew model of accumulation that stressed external markets, and the urban political economy of the years 1986-90, in which priority was given to public investment in construction as an activity favoring economic growth and employment. The interest in urban remodeling and transit renovation implied neglect of other basic sectors including education, agriculture, energy,and health. A series of fiscal measures was necessary to finance the investment program, and the inflation resulting from the investment program had significant effects on real income of the population. The new economic model encountered its competitive edge in wage depression and constant devaluations. The process of inflation-devaluation reinforced the regressive effects of the model on income, resulting in price increases for urban land and exclusion of the majority of the population from the urban housing market. The new economic model has led to dismantling of the national productive apparatus and consolidation of so-called "productive extroversion," with free economic zones and tourism the focus of accumulation related to the international market. The informal sector has grown because of inflation and because of the crisis in industrial activities destined for the internal market. Agricultural production for internal consumption declined over the decade, encouraging rural-urban migration and further swelling of the informal sector. Growth of Santo Domingo's suburbs and surrounding rural areas is 1 of the main effects of the model. By the year 2000, it is estimated that metropolitan Santo Domingo will contain 45% of the total population of the Dominican Republic. Although no exact functional correspondence can be established between urban policy and the model of accumulation, there are 3 aspects in which the dynamics of the 2 processes complement each other synergistically and perniciously: income concentration, social exclusion, and spatial segregation. Income concentration is increased by inflation and the repeated devaluations, the dismantling of small and medium-sized enterprises, and declining social expenditures. Social exclusion and spatial segregation are furthered by rising urban land prices and exclusion of most of the population from the urban land and housing market and demographic consolidation of periurban centers and rural sectors of the National District.

43 CFR 2091.5-1 - Segregation of lands resulting from withdrawal applications filed on or after October 21, 1976.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation of lands resulting from... RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.5-1 Segregation... publication and extends for a period of 2 years unless sooner terminated as set out below. (b) Segregations...

43 CFR 2091.5-2 - Segregation of lands resulting from withdrawal applications filed prior to October 21, 1976.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation of lands resulting from... RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.5-2 Segregation... modifies the term of segregation for all lands covered by the amended application to conform with the...

Multi-Contextual Segregation and Environmental Justice Research: Toward Fine-Scale Spatiotemporal Approaches

PubMed Central

Park, Yoo Min; Kwan, Mei-Po

2017-01-01

Many environmental justice studies have sought to examine the effect of residential segregation on unequal exposure to environmental factors among different social groups, but little is known about how segregation in non-residential contexts affects such disparity. Based on a review of the relevant literature, this paper discusses the limitations of traditional residence-based approaches in examining the association between socioeconomic or racial/ethnic segregation and unequal environmental exposure in environmental justice research. It emphasizes that future research needs to go beyond residential segregation by considering the full spectrum of segregation experienced by people in various geographic and temporal contexts of everyday life. Along with this comprehensive understanding of segregation, the paper also highlights the importance of assessing environmental exposure at a high spatiotemporal resolution in environmental justice research. The successful integration of a comprehensive concept of segregation, high-resolution data and fine-grained spatiotemporal approaches to assessing segregation and environmental exposure would provide more nuanced and robust findings on the associations between segregation and disparities in environmental exposure and their health impacts. Moreover, it would also contribute to significantly expanding the scope of environmental justice research. PMID:28994744

Microstructural evolution of type 304 and 316 stainless steels under neutron irradiation at LWR relevant conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Lizhen; Stoller, Roger E.; Field, Kevin G.

Extension of light water reactors' useful life will expose austenitic internal core components to irradiation damage levels beyond 100 displacements per atom (dpa), which will lead to profound microstructural evolution and consequent degradation of macroscopic properties. Microstructural evolution, including Frank loops, cavities, precipitates, and segregation at boundaries and the resultant radiation hardening in type 304 and 316 stainless steel (SS) variants, were studied in this work via experimental characterization and multiple simulation methods. Experimental data for up to 40 heats of type 304SS and 316SS variants irradiated in different reactors to 0.6–120 dpa at 275–375°C were either generated from thismore » work or collected from literature reports. These experimental data were then combined with models of Frank loop and cavity evolution, computational thermodynamics and precipitation, and ab initio and rate theory integrated radiation-induced segregation models to provide insights into microstructural evolution and degradation at higher radiation doses.« less

Microstructural evolution of type 304 and 316 stainless steels under neutron irradiation at LWR relevant conditions

DOE PAGES

Tan, Lizhen; Stoller, Roger E.; Field, Kevin G.; ...

2015-12-11

Extension of light water reactors' useful life will expose austenitic internal core components to irradiation damage levels beyond 100 displacements per atom (dpa), which will lead to profound microstructural evolution and consequent degradation of macroscopic properties. Microstructural evolution, including Frank loops, cavities, precipitates, and segregation at boundaries and the resultant radiation hardening in type 304 and 316 stainless steel (SS) variants, were studied in this work via experimental characterization and multiple simulation methods. Experimental data for up to 40 heats of type 304SS and 316SS variants irradiated in different reactors to 0.6–120 dpa at 275–375°C were either generated from thismore » work or collected from literature reports. These experimental data were then combined with models of Frank loop and cavity evolution, computational thermodynamics and precipitation, and ab initio and rate theory integrated radiation-induced segregation models to provide insights into microstructural evolution and degradation at higher radiation doses.« less

Continuum modelling of segregating tridisperse granular chute flow

NASA Astrophysics Data System (ADS)

Deng, Zhekai; Umbanhowar, Paul B.; Ottino, Julio M.; Lueptow, Richard M.

2018-03-01

Segregation and mixing of size multidisperse granular materials remain challenging problems in many industrial applications. In this paper, we apply a continuum-based model that captures the effects of segregation, diffusion and advection for size tridisperse granular flow in quasi-two-dimensional chute flow. The model uses the kinematics of the flow and other physical parameters such as the diffusion coefficient and the percolation length scale, quantities that can be determined directly from experiment, simulation or theory and that are not arbitrarily adjustable. The predictions from the model are consistent with experimentally validated discrete element method (DEM) simulations over a wide range of flow conditions and particle sizes. The degree of segregation depends on the Péclet number, Pe, defined as the ratio of the segregation rate to the diffusion rate, the relative segregation strength κij between particle species i and j, and a characteristic length L, which is determined by the strength of segregation between smallest and largest particles. A parametric study of particle size, κij, Pe and L demonstrates how particle segregation patterns depend on the interplay of advection, segregation and diffusion. Finally, the segregation pattern is also affected by the velocity profile and the degree of basal slip at the chute surface. The model is applicable to different flow geometries, and should be easily adapted to segregation driven by other particle properties such as density and shape.

43 CFR 2091.5-3 - Segregative effect and opening: Emergency withdrawals.

Code of Federal Regulations, 2011 CFR

2011-10-01

... RULES Segregation and Opening of Lands § 2091.5-3 Segregative effect and opening: Emergency withdrawals... withdrawal unless segregation is effected by the publication in the Federal Register of a notice of a...

Racial Residential Segregation and STI Diagnosis Among Non-Hispanic Blacks, 2006-2010.

PubMed

Lutfi, Khaleeq; Trepka, Mary Jo; Fennie, Kristopher P; Ibañez, Gladys; Gladwin, Hugh

2018-06-01

Sexually transmitted infections (STI) disproportionately impact non-Hispanic blacks. Racial residential segregation has been associated with negative socioeconomic outcomes. We sought to examine the association between segregation and STI diagnosis among blacks. The National Survey of Family Growth and US Census served as data sources. Five distinct dimensions represent segregation. The association between STI diagnosis and each segregation dimension was assessed with multilevel logistic regression modeling. 305 (7.4%) blacks reported STI diagnosis during the past 12 months. Depending on the dimension, segregation was a risk factor [dissimilarity aOR 2.41 (95% CI 2.38-2.43)] and a protective factor [isolation aOR 0.90 (95% CI 0.89-0.91)] for STI diagnosis. Findings suggest that STI diagnosis among blacks is associated with segregation. Additional research is needed to identify mechanisms for how segregation affects STI diagnosis and to aid in the development of interventions to decrease STIs.

Neighborhood residential segregation and mental health: a multilevel analysis on Hispanic Americans in Chicago.

PubMed

Lee, Min-Ah

2009-06-01

Compared with the relationship between neighborhood-level residential segregation and physical health of Hispanic Americans, less is known about how neighborhood residential segregation affects mental health. This study examines if, and how, neighborhood residential segregation is associated with the mental health of Puerto Rican and Mexican Americans in Chicago. Multilevel analyses reveal that neighborhood residential segregation is positively associated with depressive symptoms and anxiety in both groups. Neighborhood segregation, however, has more salient effects on the mental health of Mexican Americans. For Puerto Rican Americans, the effects of neighborhood segregation on mental health become nonsignificant after controlling for neighborhood-level income and individual-level covariates, whereas neighborhood segregation is strongly associated with the mental health of Mexican Americans even after controlling for other covariates. These findings show that living in a Mexican American-dominated community is not beneficial to mental health, in contrast to findings for physical health shown in previous studies.

Neighborhood residential segregation and physical health among Hispanic Americans: good, bad, or benign?

PubMed

Lee, Min-Ah; Ferraro, Kenneth F

2007-06-01

Although considerable evidence shows that residential segregation is deleterious to the health of African Americans, findings regarding segregation and health for Hispanic Americans are inconsistent. Competing hypotheses regarding the effects of neighborhood segregation on health are tested with data from Puerto Rican and Mexican American residents of Chicago. Multilevel analyses reveal that segregation is associated with more health problems for Puerto Rican Americans but not for Mexican Americans. In addition, the relationship between segregation and health was conditioned by generational status for Mexican Americans: Second- or later-generation Mexican Americans living in highly segregated neighborhoods had better health than first-generation Mexican Americans in such neighborhoods. These findings reveal that residential segregation has differential effects across Hispanic groups and suggest that a high degree of contact with Mexican Americans promotes health by facilitating flow of informal health resources and social support.

Analysis of Minor Component Segregation in Ternary Powder Mixtures

NASA Astrophysics Data System (ADS)

Asachi, Maryam; Hassanpour, Ali; Ghadiri, Mojtaba; Bayly, Andrew

2017-06-01

In many powder handling operations, inhomogeneity in powder mixtures caused by segregation could have significant adverse impact on the quality as well as economics of the production. Segregation of a minor component of a highly active substance could have serious deleterious effects, an example is the segregation of enzyme granules in detergent powders. In this study, the effects of particle properties and bulk cohesion on the segregation tendency of minor component are analysed. The minor component is made sticky while not adversely affecting the flowability of samples. The segregation extent is evaluated using image processing of the photographic records taken from the front face of the heap after the pouring process. The optimum average sieve cut size of components for which segregation could be reduced is reported. It is also shown that the extent of segregation is significantly reduced by applying a thin layer of liquid to the surfaces of minor component, promoting an ordered mixture.

Quality Control Review of the Defense Finance and Accounting Service Internal Audit Organization

DTIC Science & Technology

2014-12-01

Executive documented a threat to independence because they provided direction in a nonaudit service (IR End-to-End Assessment of DFAS Texarkana Operations...effect the lack of segregation of duties and system management controls has on the DFAS Texarkana Vendor Pay and Payroll functions.” Based on our...Infrastructure Management, February 10, 2014 Performance CO12PRC010TX Columbus Audit of DFAS Texarkana Vendor Pay and Payroll, November 19, 2013

The Integration Anomaly: Comparing the Effects of K-12 Education Delivery Models on Segregation in Schools

ERIC Educational Resources Information Center

Scafidi, Benjamin

2015-01-01

To shed light on the actual impact of school choice on segregation, one has to understand the counter factual--the state of segregation under the current public education system. In the late 1960s and '70s, the trend in public school racial segregation followed the trend in neighborhood segregation. That is to say both improved as American…

Asymmetric segregation of template DNA strands in basal-like human breast cancer cell lines

PubMed Central

2013-01-01

Background and methods Stem or progenitor cells from healthy tissues have the capacity to co-segregate their template DNA strands during mitosis. Here, we set out to test whether breast cancer cell lines also possess the ability to asymmetrically segregate their template DNA strands via non-random chromosome co-segregation, and whether this ability correlates with certain properties attributed to breast cancer stem cells (CSCs). We quantified the frequency of asymmetric segregation of template DNA strands in 12 human breast cancer cell lines, and correlated the frequency to molecular subtype, CD44+/CD24-/lo phenotype, and invasion/migration ability. We tested if co-culture with human mesenchymal stem cells, which are known to increase self-renewal, can alter the frequency of asymmetric segregation of template DNA in breast cancer. Results We found a positive correlation between asymmetric segregation of template DNA and the breast cancer basal-like and claudin-low subtypes. There was an inverse correlation between asymmetric segregation of template DNA and Her2 expression. Breast cancer samples with evidence of asymmetric segregation of template DNA had significantly increased invasion and borderline significantly increased migration abilities. Samples with high CD44+/CD24-/lo surface expression were more likely to harbor a consistent population of cells that asymmetrically segregated its template DNA; however, symmetric self-renewal was enriched in the CD44+/CD24-/lo population. Co-culturing breast cancer cells with human mesenchymal stem cells expanded the breast CSC pool and decreased the frequency of asymmetric segregation of template DNA. Conclusions Breast cancer cells within the basal-like subtype can asymmetrically segregate their template DNA strands through non-random chromosome segregation. The frequency of asymmetric segregation of template DNA can be modulated by external factors that influence expansion or self-renewal of CSC populations. Future studies to uncover the underlying mechanisms driving asymmetric segregation of template DNA and dictating cell fate at the time of cell division may explain how CSCs are maintained in tumors. PMID:24238140

Contextual and Developmental Differences in the Neural Architecture of Cognitive Control.

PubMed

Petrican, Raluca; Grady, Cheryl L

2017-08-09

Because both development and context impact functional brain architecture, the neural connectivity signature of a cognitive or affective predisposition may similarly vary across different ages and circumstances. To test this hypothesis, we investigated the effects of age and cognitive versus social-affective context on the stable and time-varying neural architecture of inhibition, the putative core cognitive control component, in a subsample ( N = 359, 22-36 years, 174 men) of the Human Connectome Project. Among younger individuals, a neural signature of superior inhibition emerged in both stable and dynamic connectivity analyses. Dynamically, a context-free signature emerged as stronger segregation of internal cognition (default mode) and environmentally driven control (salience, cingulo-opercular) systems. A dynamic social-affective context-specific signature was observed most clearly in the visual system. Stable connectivity analyses revealed both context-free (greater default mode segregation) and context-specific (greater frontoparietal segregation for higher cognitive load; greater attentional and environmentally driven control system segregation for greater reward value) signatures of inhibition. Superior inhibition in more mature adulthood was typified by reduced segregation in the default network with increasing reward value and increased ventral attention but reduced cingulo-opercular and subcortical system segregation with increasing cognitive load. Failure to evidence this neural profile after the age of 30 predicted poorer life functioning. Our results suggest that distinguishable neural mechanisms underlie individual differences in cognitive control during different young adult stages and across tasks, thereby underscoring the importance of better understanding the interplay among dispositional, developmental, and contextual factors in shaping adaptive versus maladaptive patterns of thought and behavior. SIGNIFICANCE STATEMENT The brain's functional architecture changes across different contexts and life stages. To test whether the neural signature of a trait similarly varies, we investigated cognitive versus social-affective context effects on the stable and time-varying neural architecture of inhibition during a period of neurobehavioral fine-tuning (age 22-36 years). Younger individuals with superior inhibition showed distinguishable context-free and context-specific neural profiles, evidenced in both static and dynamic connectivity analyses. More mature individuals with superior inhibition evidenced only context-specific profiles, revealed in the static connectivity patterns linked to increased reward or cognitive load. Delayed expression of this profile predicted poorer life functioning. Our results underscore the importance of understanding the interplay among dispositional, developmental, and contextual factors in shaping behavior. Copyright © 2017 the authors 0270-6474/17/377711-16$15.00/0.

What it feels like to be me: Linking emotional intelligence, identity, and intimacy.

PubMed

Maher, Hemali; Winston, Christine N; S, Usha Rani

2017-04-01

The search for the self and for an intimate other are the normative tasks of adolescence and early adulthood. The role of emotions in the resolution of these developmental tasks, however, remains largely under-studied, especially in non-western cultures. The objective of the present study, therefore, was to examine the relationships between emotional intelligence, identity, and intimacy, among Indian adolescents. Differences across genders (boys vs. girls) and types of school (gender segregated vs. integrated) were also explored. A sample of 486 adolescents completed measures of emotional intelligence, identity, and intimacy. Girls scored higher than boys on intimacy, and those from segregated schools scored higher, than those from integrated schools, on emotional intelligence. Significant relationships emerged between emotional intelligence, and identity and intimacy, and were invariant across the groups. These findings underscore the pivotal role that emotional intelligence plays in healthy adolescent development, irrespective of personal and environmental variables. Copyright © 2017 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Evolutionary Dynamics of Spore Killers

PubMed Central

Nauta, M. J.; Hoekstra, R. F.

1993-01-01

Spore killing in ascomycetes is a special form of segregation distortion. When a strain with the Killer genotype is crossed to a Sensitive type, spore killing is expressed by asci with only half the number of ascospores as usual, all surviving ascospores being of the Killer type. Using population genetic modeling, this paper explores conditions for invasion of Spore killers and for polymorphism of Killers, Sensitives and Resistants (which neither kill, nor get killed), as found in natural populations. The models show that a population with only Killers and Sensitives can never be stable. The invasion of Killers and stable polymorphism only occur if Killers have some additional advantage during the process of spore killing. This may be due to the effects of local sib competition or some kind of ``heterozygous'' advantage in the stage of ascospore formation or in the short diploid stage of the life cycle. This form of segregation distortion appears to be essentially different from other, well-investigated forms, and more field data are needed for a better understanding of spore killing. PMID:8293989

Developing PFC representations using reinforcement learning

PubMed Central

Reynolds, Jeremy R.; O'Reilly, Randall C.

2009-01-01

From both functional and biological considerations, it is widely believed that action production, planning, and goal-oriented behaviors supported by the frontal cortex are organized hierarchically (Fuster, 1990, Koechlin, Ody, & Kouneiher, 2003, & Miller, Galanter, & Pribram, 1960) However, the nature of the different levels of the hierarchy remains unclear, and little attention has been paid to the origins of such a hierarchy. We address these issues through biologically-inspired computational models that develop representations through reinforcement learning. We explore several different factors in these models that might plausibly give rise to a hierarchical organization of representations within the PFC, including an initial connectivity hierarchy within PFC, a hierarchical set of connections between PFC and subcortical structures controlling it, and differential synaptic plasticity schedules. Simulation results indicate that architectural constraints contribute to the segregation of different types of representations, and that this segregation facilitates learning. These findings are consistent with the idea that there is a functional hierarchy in PFC, as captured in our earlier computational models of PFC function and a growing body of empirical data. PMID:19591977

Planet signatures and Size Segregation in Debris Discs

NASA Astrophysics Data System (ADS)

Thébault, Philippe

2014-01-01

The response of a debris disc to a planetary perturber is the result of the complex interplay between gravitational effects, grain collisions and stellar radiation pressure (Stark & Kuchner (2009). We investigate to what extent this response can depart from the pure gravitational case when including grain collisional production and radiation pressure. We use the DyCoSS code (Thébault (2012), designed to study the coupled effect of collisions and dynamics for systems at steady state with one perturbing body. We focus on two outcomes: the 2D surface density profile of the disc+planet system, and the way the Particle Size Distribution (PSD) is spatially segregated within the disc. We consider two set-ups: 1) a narrow ring with an exterior ``shepherding'' planet, and 2) an extended disc in which a planet is embedded. For each case, the planet mass and orbit are explored as free parameters, and an unperturbed ``no-planet'' case is also considered. Another parameter is the disc's collisional activity, as parameterized by its optical depth τ.

Marker chromosome genomic structure and temporal origin implicate a chromoanasynthesis event in a family with pleiotropic psychiatric phenotypes.

PubMed

Grochowski, Christopher M; Gu, Shen; Yuan, Bo; Tcw, Julia; Brennand, Kristen J; Sebat, Jonathan; Malhotra, Dheeraj; McCarthy, Shane; Rudolph, Uwe; Lindstrand, Anna; Chong, Zechen; Levy, Deborah L; Lupski, James R; Carvalho, Claudia M B

2018-04-25

Small supernumerary marker chromosomes (sSMC) are chromosomal fragments difficult to characterize genomically. Here, we detail a proband with schizoaffective disorder and a mother with bipolar disorder with psychotic features who present with a marker chromosome that segregates with disease. We explored the architecture of this marker and investigated its temporal origin. Array comparative genomic hybridization (aCGH) analysis revealed three duplications and three triplications that spanned the short arm of chromosome 9, suggestive of a chromoanasynthesis-like event. Segregation of marker genotypes, phased using sSMC mosaicism in the mother, provided evidence that it was generated during a germline-level event in the proband's maternal grandmother. Whole-genome sequencing (WGS) was performed to resolve the structure and junctions of the chromosomal fragments, revealing further complexities. While structural variations have been previously associated with neuropsychiatric disorders and marker chromosomes, here we detail the precise architecture, human life-cycle genesis, and propose a DNA replicative/repair mechanism underlying formation. © 2018 Wiley Periodicals, Inc.

Differential segregation of nodaviral coat protein and RNA into progeny virions during mixed infection with FHV and NoV

PubMed Central

Gopal, Radhika; Venter, P. Arno; Schneemann, Anette

2014-01-01

Nodaviruses are icosahedral viruses with a bipartite, positive-sense RNA genome. The two RNAs are packaged into a single virion by a poorly understood mechanism. We chose two distantly related nodaviruses, Flock House virus and Nodamura virus, to explore formation of viral reassortants as a means to further understand genome recognition and encapsidation. In mixed infections, the viruses were incompatible at the level of RNA replication and their coat proteins segregated into separate populations of progeny particles. RNA packaging, on the other hand, was indiscriminate as all four viral RNAs were detectable in each progeny population. Consistent with the trans-encapsidation phenotype, fluorescence in situ hybridization of viral RNA revealed that the genomes of the two viruses co-localized throughout the cytoplasm. Our results imply that nodaviral RNAs lack rigorously defined packaging signals and that coencapsidation of the viral RNAs does not require a pair of cognate RNA1 and RNA2. PMID:24725955

7 CFR 996.13 - Peanuts.

Code of Federal Regulations, 2014 CFR

2014-01-01

... from visible Aspergillus flavus. (c) Segregation 2. “Segregation 2 peanuts” means farmers stock peanuts... rancidity, mold, or decay and which are free from visible Aspergillus flavus. (d) Segregation 3. “Segregation 3 peanuts” means farmers stock peanuts with visible Aspergillus flavus. ...

7 CFR 996.13 - Peanuts.

Code of Federal Regulations, 2013 CFR

2013-01-01

... from visible Aspergillus flavus. (c) Segregation 2. “Segregation 2 peanuts” means farmers stock peanuts... rancidity, mold, or decay and which are free from visible Aspergillus flavus. (d) Segregation 3. “Segregation 3 peanuts” means farmers stock peanuts with visible Aspergillus flavus. ...

7 CFR 996.13 - Peanuts.

Code of Federal Regulations, 2012 CFR

2012-01-01

... from visible Aspergillus flavus. (c) Segregation 2. “Segregation 2 peanuts” means farmers stock peanuts... rancidity, mold, or decay and which are free from visible Aspergillus flavus. (d) Segregation 3. “Segregation 3 peanuts” means farmers stock peanuts with visible Aspergillus flavus. ...

Undocumented Migration and the Residential Segregation of Mexicans in New Destinations1

PubMed Central

Hall, Matthew; Stringfield, Jonathan

2014-01-01

This study uses data from the 2000 Census and 2005–2009 American Community Survey to examine the impact of undocumented Mexican migration to new destinations on residential segregation between Mexican immigrants and native-born whites and native-born blacks. We find that Mexican-white and Mexican-black segregation is higher in new Mexican gateways than in established areas and that, for Mexican-immigrant segregation from whites, this heightened level of residential segregation in new destinations can be explained by the high presence of unauthorized Mexican immigrants living there which tends to bolster segregation between the two groups. By contrast, Mexican-immigrant segregation from native-born blacks tends to be lower in areas with larger undocumented populations, a pattern that is especially true in new destinations. Neither of these opposing effects of legal status on Mexican-immigrant segregation can be explained by compositional differences in assimilation (English ability and earnings) between documented and undocumented immigrants nor by structural variation in metropolitan areas, suggesting a unique association between legal status and segregation. PMID:24913945

Artificial Symmetry-Breaking for Morphogenetic Engineering Bacterial Colonies.

PubMed

Nuñez, Isaac N; Matute, Tamara F; Del Valle, Ilenne D; Kan, Anton; Choksi, Atri; Endy, Drew; Haseloff, Jim; Rudge, Timothy J; Federici, Fernan

2017-02-17

Morphogenetic engineering is an emerging field that explores the design and implementation of self-organized patterns, morphologies, and architectures in systems composed of multiple agents such as cells and swarm robots. Synthetic biology, on the other hand, aims to develop tools and formalisms that increase reproducibility, tractability, and efficiency in the engineering of biological systems. We seek to apply synthetic biology approaches to the engineering of morphologies in multicellular systems. Here, we describe the engineering of two mechanisms, symmetry-breaking and domain-specific cell regulation, as elementary functions for the prototyping of morphogenetic instructions in bacterial colonies. The former represents an artificial patterning mechanism based on plasmid segregation while the latter plays the role of artificial cell differentiation by spatial colocalization of ubiquitous and segregated components. This separation of patterning from actuation facilitates the design-build-test-improve engineering cycle. We created computational modules for CellModeller representing these basic functions and used it to guide the design process and explore the design space in silico. We applied these tools to encode spatially structured functions such as metabolic complementation, RNAPT7 gene expression, and CRISPRi/Cas9 regulation. Finally, as a proof of concept, we used CRISPRi/Cas technology to regulate cell growth by controlling methionine synthesis. These mechanisms start from single cells enabling the study of morphogenetic principles and the engineering of novel population scale structures from the bottom up.

Residential Segregation and School Integration.

ERIC Educational Resources Information Center

Rivkin, Steven G.

1994-01-01

Asserts that school districts' efforts to integrate schools have failed to ameliorate the racial isolation of black students. Finds that schools remain segregated primarily because of continued residential segregation and that school integration efforts have had little long-term effect on residential segregation. (CFR)

WASH and Tsg101/ALIX-dependent diversion of stress-internalized EGFR from the canonical endocytic pathway

PubMed Central

Tomas, Alejandra; Vaughan, Simon O.; Burgoyne, Thomas; Sorkin, Alexander; Hartley, John A.; Hochhauser, Daniel; Futter, Clare E.

2015-01-01

Stress exposure triggers ligand-independent EGF receptor (EGFR) endocytosis, but its post-endocytic fate and role in regulating signalling are unclear. We show that the p38 MAP kinase-dependent, EGFR tyrosine kinase (TK)-independent EGFR internalization induced by ultraviolet light C (UVC) or the cancer therapeutic cisplatin, is followed by diversion from the canonical endocytic pathway. Instead of lysosomal degradation or plasma membrane recycling, EGFR accumulates in a subset of LBPA-rich perinuclear multivesicular bodies (MVBs) distinct from those carrying EGF-stimulated EGFR. Stress-internalized EGFR co-segregates with exogenously expressed pre-melanosomal markers OA1 and fibrillar PMEL, following early endosomal sorting by the actin polymerization-promoting WASH complex. Stress-internalized EGFR is retained intracellularly by continued p38 activity in a mechanism involving ubiquitin-independent, ESCRT/ALIX-dependent incorporation onto intraluminal vesicles (ILVs) of MVBs. In contrast to the internalization-independent EGF-stimulated activation, UVC/cisplatin-triggered EGFR activation depends on EGFR internalization and intracellular retention. EGFR signalling from this MVB subpopulation delays apoptosis and might contribute to chemoresistance. PMID:26066081

Sound segregation via embedded repetition is robust to inattention.

PubMed

Masutomi, Keiko; Barascud, Nicolas; Kashino, Makio; McDermott, Josh H; Chait, Maria

2016-03-01

The segregation of sound sources from the mixture of sounds that enters the ear is a core capacity of human hearing, but the extent to which this process is dependent on attention remains unclear. This study investigated the effect of attention on the ability to segregate sounds via repetition. We utilized a dual task design in which stimuli to be segregated were presented along with stimuli for a "decoy" task that required continuous monitoring. The task to assess segregation presented a target sound 10 times in a row, each time concurrent with a different distractor sound. McDermott, Wrobleski, and Oxenham (2011) demonstrated that repetition causes the target sound to be segregated from the distractors. Segregation was queried by asking listeners whether a subsequent probe sound was identical to the target. A control task presented similar stimuli but probed discrimination without engaging segregation processes. We present results from 3 different decoy tasks: a visual multiple object tracking task, a rapid serial visual presentation (RSVP) digit encoding task, and a demanding auditory monitoring task. Load was manipulated by using high- and low-demand versions of each decoy task. The data provide converging evidence of a small effect of attention that is nonspecific, in that it affected the segregation and control tasks to a similar extent. In all cases, segregation performance remained high despite the presence of a concurrent, objectively demanding decoy task. The results suggest that repetition-based segregation is robust to inattention. (c) 2016 APA, all rights reserved).

Twenty Years after Brown: Where Are We Now?

ERIC Educational Resources Information Center

Edelman, Marian Wright

1974-01-01

To resolve the basic question of what is unconstitutional school segregation, lawyer Edelman suggests bombarding the citadel of de facto segregation with a legal strategy that expands the definition of de jure segregation to include acts that produce segregation in fact. (Editor)

49 CFR 175.78 - Stowage compatibility of cargo.

Code of Federal Regulations, 2010 CFR

2010-10-01

... leakage. (b) At a minimum, the segregation instructions prescribed in the following Segregation Table must be followed to maintain acceptable segregation between packages containing hazardous materials with different hazards. The Segregation Table instructions apply whether or not the class or division is the...

Quality-by-design (QbD): effects of testing parameters and formulation variables on the segregation tendency of pharmaceutical powder measured by the ASTM D 6940-04 segregation tester.

PubMed

Xie, Lin; Wu, Huiquan; Shen, Meiyu; Augsburger, Larry L; Lyon, Robbe C; Khan, Mansoor A; Hussain, Ajaz S; Hoag, Stephen W

2008-10-01

The objective of this study was to examine the effects of testing parameters and formulation variables on the segregation tendency of pharmaceutical powders measured by the ASTM D 6940-04 segregation tester using design of experiments (DOE) approaches. The test blends consisted of 4% aspirin (ASP) and 96% microcrystalline cellulose (MCC) with and without magnesium stearate (MgS). The segregation tendency of a blend was determined by measuring the last/first (L/F) ratio, the ratio of aspirin concentrations between the first and last samples discharged from the tester. A 2(2) factorial design was used to determine the effects of measurement parameters [amount of material loaded (W), number of segregation cycles] with number of replicates 6. ANOVA showed that W was a critical parameter for segregation testing. The L/F value deviated further from 1 (greater segregation tendency) with increasing W. A 2(3) full factorial design was used to assess the effects of formulation variables: grade of ASP (unmilled, milled), grade of MCC, and amount of lubricant, MgS. MLR and ANOVA showed that the grade of ASP was the main effect contributing to segregation tendency. Principal Component Regression Analysis established a correlation between L/F and the physical properties of the blend related to ASP and MCC, the ASP/MCC particle size ratio (PSR) and powder cohesion. The physical properties of the blend related to density and flow were not influenced by the grade of ASP and were not related to the segregation tendency of the blend. The direct relationship between L/F and PSR was determined by univariate analysis. Segregation tendency increased as the ASP to MCC particle size increased. This study highlighted critical test parameters for segregation testing and identified critical physical properties of the blends that influence segregation tendency. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

18 CFR 401.113 - Segregable materials.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

18 CFR 401.113 - Segregable materials.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

18 CFR 401.113 - Segregable materials.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

18 CFR 401.113 - Segregable materials.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Segregable materials. 401.113 Section 401.113 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... Segregable materials. Any reasonably segregable portion of a record shall be provided to any person...

49 CFR 176.708 - Segregation distances.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation distances. 176.708 Section 176.708... Requirements for Radioactive Materials § 176.708 Segregation distances. (a) Table IV lists minimum separation... into account any relocation of cargo during the voyage. (e) Any departure from the segregation...

49 CFR 176.145 - Segregation in single hold vessels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Segregation in single hold vessels. 176.145 Section 176.145 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.145 Segregation in...

43 CFR 2091.07 - Principles.

Code of Federal Regulations, 2011 CFR

2011-10-01

... OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of... the Geothermal Steam Act, if so specified in the document that segregates the lands. The segregation... are required when the opening date is not specified in the document creating the segregation, or when...

49 CFR 176.145 - Segregation in single hold vessels.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Segregation in single hold vessels. 176.145 Section 176.145 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... VESSEL Detailed Requirements for Class 1 (Explosive) Materials Segregation § 176.145 Segregation in...

Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter

PubMed Central

Trathan, Philip N.; Ceia, Filipe R.; Tarling, Geraint A.; Adlard, Stacey; Fox, Derren; Edwards, Ewan W. J.; Vieira, Rui P.; Medeiros, Renata; De Broyer, Claude; Cherel, Yves

2017-01-01

Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the “Intersexual Competition Hypothesis” for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in that they have a wider habitat and trophic niche during the Antarctic Winter (in comparison to Summer). We also detected individual specialization in feeding/trophic levels for each gender, with certain males feeding mainly on fish and certain females mainly on crustaceans, which may be driven the prevailing environmental conditions that lead individuals to search for alternative prey, and cause sexual diet segregation. Our results provide further information to help improve understanding about sexual segregation and individual specialization of marine organisms, while contributing valuable information on the winter diet for Antarctic monitoring programs and for modelling Antarctic marine food webs. PMID:28362847

Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter.

PubMed

Xavier, José C; Trathan, Philip N; Ceia, Filipe R; Tarling, Geraint A; Adlard, Stacey; Fox, Derren; Edwards, Ewan W J; Vieira, Rui P; Medeiros, Renata; De Broyer, Claude; Cherel, Yves

2017-01-01

Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the "Intersexual Competition Hypothesis" for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in that they have a wider habitat and trophic niche during the Antarctic Winter (in comparison to Summer). We also detected individual specialization in feeding/trophic levels for each gender, with certain males feeding mainly on fish and certain females mainly on crustaceans, which may be driven the prevailing environmental conditions that lead individuals to search for alternative prey, and cause sexual diet segregation. Our results provide further information to help improve understanding about sexual segregation and individual specialization of marine organisms, while contributing valuable information on the winter diet for Antarctic monitoring programs and for modelling Antarctic marine food webs.

The joint effect of ethnicity and gender on occupational segregation. An approach based on the Mutual Information Index.

PubMed

Guinea-Martin, Daniel; Mora, Ricardo; Ruiz-Castillo, Javier

2015-01-01

In this article, we study the effects of ethnicity and gender on occupational segregation. Traditionally, researchers have examined the two sources of segregation separately. In contrast, we measure their joint effect by applying a multigroup segregation index-the Mutual Information or M index-to the product of the seven ethnic groups and two genders distinguished in our 2001 Census data for England and Wales. We exploit M's additive decomposability property to pose the following two questions: (i) Is there an interaction effect? (ii) How much does each source contribute to occupational segregation, controlling for the effect of the other? Although the role of ethnicity is non-negligible in the areas where minorities are concentrated, our findings confirm the greater importance of gender over ethnicity as a source of segregation. Moreover, we find a small "dwindling" interaction effect between the two sources of segregation: ethnicity slightly weakens the segregating power of gender and vice versa. Copyright © 2014 Elsevier Inc. All rights reserved.

Factors shaping workplace segregation between natives and immigrants.

PubMed

Strömgren, Magnus; Tammaru, Tiit; Danzer, Alexander M; van Ham, Maarten; Marcińczak, Szymon; Stjernström, Olof; Lindgren, Urban

2014-04-01

Research on segregation of immigrant groups is increasingly turning its attention from residential areas toward other important places, such as the workplace, where immigrants can meet and interact with members of the native population. This article examines workplace segregation of immigrants. We use longitudinal, georeferenced Swedish population register data, which enables us to observe all immigrants in Sweden for the period 1990-2005 on an annual basis. We compare estimates from ordinary least squares with fixed-effects regressions to quantify the extent of immigrants' self-selection into specific workplaces, neighborhoods, and partnerships, which may bias more naïve ordinary least squares results. In line with previous research, we find lower levels of workplace segregation than residential segregation. The main finding is that low levels of residential segregation reduce workplace segregation, even after we take into account intermarriage with natives as well as unobserved characteristics of immigrants' such as willingness and ability to integrate into the host society. Being intermarried with a native reduces workplace segregation for immigrant men but not for immigrant women.

Local Residential Segregation Matters: Stronger Association of Census Tract Compared to Conventional City-Level Measures with Fatal and Non-Fatal Assaults (Total and Firearm Related), Using the Index of Concentration at the Extremes (ICE) for Racial, Economic, and Racialized Economic Segregation, Massachusetts (US), 1995-2010.

PubMed

Krieger, Nancy; Feldman, Justin M; Waterman, Pamela D; Chen, Jarvis T; Coull, Brent A; Hemenway, David

2017-04-01

Research on residential segregation and health, primarily conducted in the USA, has chiefly employed city or regional measures of racial segregation. To test our hypothesis that stronger associations would be observed using local measures, especially for racialized economic segregation, we analyzed risk of fatal and non-fatal assault in Massachusetts (1995-2010), since this outcome is strongly associated with residential segregation. The segregation metrics comprised the Index of Concentration at the Extremes (ICE), the Index of Dissimilarity, and poverty rate, with measures computed at both the census tract and city/town level. Key results were that larger associations between fatal and non-fatal assaults and residential segregation occurred for models using the census tract vs. city/town measures, with the greatest associations observed for racialized economic segregation. For fatal assaults, comparing the bottom vs. top quintiles, the incidence rate ratio (and 95% confidence interval (CI)) in models using the census tract measures equaled 3.96 (95% CI 3.10, 5.06) for the ICE for racialized economic segregation, 3.26 (95% CI 2.58, 4.14) for the ICE for income, 3.14 (95% CI 2.47, 3.99) for poverty, 2.90 (95% CI 2.21, 3.81) for the ICE for race/ethnicity, and only 0.93 (95% CI 0.79, 1.11) for the Index of Dissimilarity; in models that included both census tract and city/town ICE measures, this risk ratio for the ICE for racialized economic segregation was higher at the census tract (3.29; 95% CI 2.43, 4.46) vs. city/town level (1.61; 95% CI 1.12, 2.32). These results suggest that, at least in the case of fatal and non-fatal assaults, research on residential segregation should employ local measures, including of racialized economic segregation, to avoid underestimating the adverse impact of segregation on health.

DNA and origin region segregation are not affected by the transition from rod to sphere after inhibition of Escherichia coli MreB by A22.

PubMed

Karczmarek, Aneta; Martínez-Arteaga, Rocío; Baselga, Rocío Martínez-Arteaga; Alexeeva, Svetlana; Hansen, Flemming G; Vicente, Miguel; Nanninga, Nanne; den Blaauwen, Tanneke

2007-07-01

The bacterial actin homologue MreB forms a helix underneath the cytoplasmic membrane and was shown to be essential in the morphogenesis of the rod-shaped cells. Additionally, MreB was implicated to be involved in DNA segregation. However, in our hands the mreBCD deletion strain (PA340-678) grew without apparent DNA segregation defect, suggesting that the reported chromosome segregation inhibition could be caused by a temporarily effect of MreB inhibition or depletion. To assess the involvement of MreB in DNA segregation during the transition from rod to sphere, we compared the effect of A22 and the PBP2 inhibitor mecillinam on the percentage of cells with segregated nucleoids and the number of oriC foci in wild-type Escherichia coli cells. Cells became spherical in the same time window during both treatments and we could not detect any difference in the chromosome or oriC segregation between these two treatments. Additionally, flow cytometric analyses showed that A22 and mecillinam treatment gave essentially the same chromosome segregation pattern. We conclude that MreB is not directly involved in DNA segregation of E. coli.

C-Cr segregation at grain boundary before the carbide nucleation in Alloy 690

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Hui, E-mail: huili@shu.edu.cn; Laboratory for Microstructures, Shanghai University, Shanghai, 200444; Xia Shuang

2012-04-15

The grain boundary segregation in Alloy 690 was investigated by atom probe tomography. B, C and Si segregated at the grain boundary. The high concentration regions for each segregation element form a set of straight arrays that are parallel to each other in the grain boundary plane. The concentration fluctuation has a periodicity of about 7 nm in the grain boundary plane. Before the Cr{sub 23}C{sub 6} nucleation at grain boundaries, the C-Cr co-segregate on one side of the grain boundaries while not the exact grain boundary core regions have been detected. The reasons why grain boundary carbides have coherentmore » orientation relationship only with one side of nearby grain which grain boundary is located at high index crystal plane were discussed. - Highlights: Black-Right-Pointing-Pointer Grain boundary segregation in Alloy 690 was investigated by atom probe tomography. Black-Right-Pointing-Pointer B, C and Si segregate at the grain boundary. Black-Right-Pointing-Pointer Concentration of segregated atoms periodicity fluctuated in the grain boundary plane. Black-Right-Pointing-Pointer C and Cr co-segregate on one side of the grain boundary before carbide nucleation.« less

How Segregation Makes Us Fat: Food Behaviors and Food Environment as Mediators of the Relationship Between Residential Segregation and Individual Body Mass Index.

PubMed

Goodman, Melody; Lyons, Sarah; Dean, Lorraine T; Arroyo, Cassandra; Hipp, James Aaron

2018-01-01

Racial residential segregation affects food landscapes that dictate residents' food environments and is associated with obesity risk factors, including individual dietary patterns and behaviors. We examine if food behaviors and environments mediate the association between segregation and body mass index (BMI). Non-Hispanic Whites and Blacks living in the St. Louis and Kansas City metro regions from 2012 to 2013 were surveyed on dietary behaviors, food environment, and BMI ( n  = 1,412). These data were combined with the CDC's modified retail food environment index and 2012 American Community Survey data to calculate racial segregation using various evenness and exposure indices. Multi-level mediation analyses were conducted to determine if dietary behavior and food environment mediate the association between racial residential segregation and individual BMI. The positive association between racial segregation and individual BMI is partially mediated by dietary behaviors and fully mediated by food environments. Racial segregation (evenness and exposure) is associated with BMI, mediated by dietary behaviors and food environment. Elements of the food environment, which form the context for dietary behaviors, are potential targets for interventions to reduce obesity in residentially segregated areas.

Health Care Waste Segregation Behavior among Health Workers in Uganda: An Application of the Theory of Planned Behavior.

PubMed

Akulume, Martha; Kiwanuka, Suzanne N

2016-01-01

Objective . The goal of this study was to assess the appropriateness of the theory of planned behavior in predicting health care waste segregation behaviors and to examine the factors that influence waste segregation behaviors. Methodology . One hundred and sixty-three health workers completed a self-administered questionnaire in a cross-sectional survey that examined the theory of planned behavior constructs (attitudes, subjective norms, perceived behavioral control, and intention) and external variables (sociodemographic factors, personal characteristics, organizational characteristics, professional characteristics, and moral obligation). Results . For their most recent client 21.5% of the health workers reported that they most definitely segregated health care waste while 5.5% did not segregate. All the theory of planned behavior constructs were significant predictors of health workers' segregation behavior, but intention emerged as the strongest and most significant ( r = 0.524, P < 0.001). The theory of planned behavior model explained 52.5% of the variance in health workers' segregation behavior. When external variables were added, the new model explained 66.7% of the variance in behavior. Conclusion . Generally, health workers' health care waste segregation behavior was high. The theory of planned behavior significantly predicted health workers' health care waste segregation behaviors.

Sequential stream segregation in normally-hearing and cochlear-implant listenersa)

PubMed Central

Tejani, Viral D.; Schvartz-Leyzac, Kara C.; Chatterjee, Monita

2017-01-01

Sequential stream segregation by normal hearing (NH) and cochlear implant (CI) listeners was investigated using an irregular rhythm detection (IRD) task. Pure tones and narrowband noises of different bandwidths were presented monaurally to older and younger NH listeners via headphones. For CI users, stimuli were delivered as pure tones via soundfield and via direct electrical stimulation. Results confirmed that tonal pitch is not essential for stream segregation by NH listeners and that aging does not reduce NH listeners' stream segregation. CI listeners' stream segregation was significantly poorer than NH listeners' with pure tone stimuli. With direct stimulation, however, CI listeners showed significantly stronger stream segregation, with a mean normalized pattern similar to NH listeners, implying that the CI speech processors possibly degraded acoustic cues. CI listeners' performance on an electrode discrimination task indicated that cues that are salient enough to make two electrodes highly discriminable may not be sufficiently salient for stream segregation, and that gap detection/discrimination, which must depend on perceptual electrode differences, did not play a role in the IRD task. Although the IRD task does not encompass all aspects of full stream segregation, these results suggest that some CI listeners may demonstrate aspects of stream segregation. PMID:28147600

27 CFR 24.27 - Segregation of operations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Segregation of operations. 24.27 Section 24.27 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU... Segregation of operations. The appropriate TTB officer may require the proprietor to segregate operations...

27 CFR 24.27 - Segregation of operations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Segregation of operations. 24.27 Section 24.27 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU... Segregation of operations. The appropriate TTB officer may require the proprietor to segregate operations...

28 CFR 541.24 - Disciplinary segregation status.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Disciplinary segregation status. 541.24... INMATE DISCIPLINE AND SPECIAL HOUSING UNITS Special Housing Units § 541.24 Disciplinary segregation status. You may be placed in disciplinary segregation status only by the DHO as a disciplinary sanction. ...

Racial and Ethnic Residential Segregation, the Neighborhood Socioeconomic Environment, and Obesity Among Blacks and Mexican Americans

PubMed Central

Kershaw, Kiarri N.; Albrecht, Sandra S.; Carnethon, Mercedes R.

2013-01-01

We used cross-sectional data on 2,660 black and 2,611 Mexican-American adult participants in the National Health and Nutrition Examination Survey (1999–2006) to investigate the association between metropolitan-level racial/ethnic residential segregation and obesity and to determine whether it was mediated by the neighborhood socioeconomic environment. Residential segregation was measured using the black and Hispanic isolation indices. Neighborhood poverty and negative income incongruity were assessed as mediators. Multilevel Poisson regression with robust variance estimates was used to estimate prevalence ratios. There was no relationship between segregation and obesity among men. Among black women, in age-, nativity-, and metropolitan demographic-adjusted models, high segregation was associated with a 1.29 (95% confidence interval (CI): 1.00, 1.65) times higher obesity prevalence than was low segregation; medium segregation was associated with a 1.35 (95% CI: 1.07, 1.70) times higher obesity prevalence. Mexican-American women living in high versus low segregation areas had a significantly lower obesity prevalence (prevalence ratio, 0.54; 95% CI: 0.33, 0.90), but there was no difference between those living in medium versus low segregation areas. These associations were not mediated by neighborhood poverty or negative income incongruity. These findings suggest variability in the interrelationships between residential segregation and obesity for black and Mexican-American women. PMID:23337312

Do Diabetic Patients Living in Racially Segregated Neighborhoods Experience Different Access and Quality of Care?

PubMed Central

Chan, Kitty S.; Gaskin, Darrell J.; Dinwiddie, Gniesha Y.; McCleary, Rachael

2012-01-01

Background Place of residence, particularly residential segregation, has been implicated in health and health care disparities. However, prior studies have not focused on care for diabetes, a prevalent condition for minority populations. Objective To examine the association of residential segregation with a range of access and quality of care outcomes among Black and Hispanic diabetics using a nationally representative U.S. sample. Research Design Cross-sectional study using data for 1598 adult diabetics from the 2006 Medical Expenditure Panel Survey (MEPS) linked to residential segregation information for Blacks and Hispanics based on the 2000 census. Relationships of five dimensions of residential segregation (dissimilarity, isolation, clustering, concentration and centralization) with access and quality of care outcomes were examined using linear, logistic and multinomial logistic regression models, controlling for respondent characteristics and community utilization and hospital capacity. Results Black and Hispanic diabetics had comparable or better access to providers, but received fewer recommended services. Living in a segregated community was associated with more recommended services received, but also problems with seeing a specialist. The relationship of residential segregation to diabetes care varied depending on type of segregation and race/ethnic group assessed. Conclusions Residential segregation influences the care experience of diabetics in the U.S. Our study highlights the importance of investigating how different types of segregation may affect diabetes care received by patients from different race and ethnic groups. PMID:22525608

Residential segregation and the survival of U.S. urban public hospitals.

PubMed

Ko, Michelle; Needleman, Jack; Derose, Kathryn Pitkin; Laugesen, Miriam J; Ponce, Ninez A

2014-06-01

Residential segregation is associated geographic disparities in access to care, but its impact on local health care policy, including public hospitals, is unknown. We examined the effects of racial residential segregation on U.S. urban public hospital closures from 1987 to 2007, controlling for hospital, market, and policy characteristics. We found that a high level of residential segregation moderated the protective effects of Black population composition, such that a high level of residential segregation, in combination with a high percentage of poor residents, conferred a higher likelihood of hospital closure. More segregated and poorer communities face disadvantages in access to care that may be compounded as a result of instability in the health care safety net. Policy makers should consider the influence of social factors such as residential segregation on the allocation of the safety net resources.

Annealing Increases Stability Of Iridium Thermocouples

NASA Technical Reports Server (NTRS)

Germain, Edward F.; Daryabeigi, Kamran; Alderfer, David W.; Wright, Robert E.; Ahmed, Shaffiq

1989-01-01

Metallurgical studies carried out on samples of iridium versus iridium/40-percent rhodium thermocouples in condition received from manufacturer. Metallurgical studies included x-ray, macroscopic, resistance, and metallographic studies. Revealed large amount of internal stress caused by cold-working during manufacturing, and large number of segregations and inhomogeneities. Samples annealed in furnace at temperatures from 1,000 to 2,000 degree C for intervals up to 1 h to study effects of heat treatment. Wire annealed by this procedure found to be ductile.

46 CFR 148.155 - Stowage and segregation for potentially dangerous materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Stowage and segregation for potentially dangerous...) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.155 Stowage and segregation for potentially dangerous materials. (a) A PDM must be stowed and...

46 CFR 148.155 - Stowage and segregation for potentially dangerous materials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Stowage and segregation for potentially dangerous...) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.155 Stowage and segregation for potentially dangerous materials. (a) A PDM must be stowed and...

46 CFR 148.155 - Stowage and segregation for potentially dangerous materials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Stowage and segregation for potentially dangerous...) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.155 Stowage and segregation for potentially dangerous materials. (a) A PDM must be stowed and...

43 CFR 2440.4 - Specific criteria for segregative effect of classification for disposal.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of classification for disposal. 2440.4 Section 2440.4 Public Lands: Interior Regulations Relating to... (2000) SEGREGATION BY CLASSIFICATION Criteria for Segregation § 2440.4 Specific criteria for segregative effect of classification for disposal. Public lands classified or proposed to be classified for disposal...

43 CFR 2440.3 - Specific criteria for segregative effect of classification for retention.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of classification for retention. 2440.3 Section 2440.3 Public Lands: Interior Regulations Relating to... (2000) SEGREGATION BY CLASSIFICATION Criteria for Segregation § 2440.3 Specific criteria for segregative effect of classification for retention. (a) Public lands classified or proposed to be classified for...

36 CFR 254.6 - Segregative effect.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Segregative effect. 254.6... ADJUSTMENTS Land Exchanges § 254.6 Segregative effect. (a) If a proposal is made to exchange Federal lands... segregative effect terminates as follows: (1) Automatically, upon issuance of a patent or other document of...

50 Years after "Brown": Segregation in the Miami-Dade County Public Schools

ERIC Educational Resources Information Center

Moore, James

2004-01-01

Fifty years after the "Brown v. Board of Education" decision outlawed de jure segregation in American schools, many school districts remain segregated. Despite numerous efforts aimed at desegregation, residential segregation--the primary barrier to significant school desegregation--remains entrenched throughout the United States. The Miami-Dade…

Neighborhood Residential Segregation and Physical Health among Hispanic Americans: Good, Bad, or Benign?

ERIC Educational Resources Information Center

Lee, Min-Ah; Ferraro, Kenneth F.

2007-01-01

Although considerable evidence shows that residential segregation is deleterious to the health of African Americans, findings regarding segregation and health for Hispanic Americans are inconsistent. Competing hypotheses regarding the effects of neighborhood segregation on health are tested with data from Puerto Rican and Mexican American…

Development of a test to measure the tendency for a hot-mix asphalt to segregate

DOT National Transportation Integrated Search

2000-02-01

Hot Mix Asphalt tends to segregate during handling and placement. The use of a test to determine the tendency to segregate would assist the user in determining when a mix gradation needs adjustment to avoid construction of a segregated pavement or wh...

76 FR 76180 - Notice of Realty Action: Termination of Segregation, Opening of Public Lands; Montana

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-06

...] Notice of Realty Action: Termination of Segregation, Opening of Public Lands; Montana AGENCY: Bureau of... generally, subject to valid existing rights, the provisions of existing withdrawals, other segregations of..., subject to valid existing rights, the provision of existing withdrawals, other segregations of record, and...

Student Mobility, Segregation, and Achievement Gaps: Evidence from Clark County, Nevada

ERIC Educational Resources Information Center

Welsh, Richard O.

2018-01-01

Student mobility and school segregation are two important issues with significant equity implications for urban school districts that are often addressed separately. This article examines the relationship between student mobility and school segregation. The findings indicate that more segregated schools typically have smaller within-school…

78 FR 4365 - Capital, Margin, and Segregation Requirements for Security-Based Swap Dealers and Major Security...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-22

... 3235-AL12 Capital, Margin, and Segregation Requirements for Security-Based Swap Dealers and Major... public comment to establish capital, margin, and segregation requirements for security-based swap dealers... soliciting comment on proposed rules and rule amendments establishing capital, margin, and segregation...

46 CFR 148.155 - Stowage and segregation for potentially dangerous materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation for potentially dangerous...) DANGEROUS CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.155 Stowage and segregation for potentially dangerous materials. (a) A PDM must be stowed and...

Indian Residential Segregation in the Urban Southwest: 1970 and 1980.

ERIC Educational Resources Information Center

Bohland, James R.

1982-01-01

Indian segregation in 11 cities in the Southwest in 1970 and 1980 was less than the segregation of either Blacks or Spanish Americans. Indian segregation declined between 1970 and 1980, but the decline was least in cities experiencing the greatest growth in Indian population. (Author/AM)

A novel prognostic model in myeloma based on co-segregating adverse FISH lesions and the ISS: analysis of patients treated in the MRC Myeloma IX trial.

PubMed

Boyd, K D; Ross, F M; Chiecchio, L; Dagrada, G P; Konn, Z J; Tapper, W J; Walker, B A; Wardell, C P; Gregory, W M; Szubert, A J; Bell, S E; Child, J A; Jackson, G H; Davies, F E; Morgan, G J

2012-02-01

The association of genetic lesions detected by fluorescence in situ hybridization (FISH) with survival was analyzed in 1069 patients with newly presenting myeloma treated in the Medical Research Council Myeloma IX trial, with the aim of identifying patients associated with the worst prognosis. A comprehensive FISH panel was performed, and the lesions associated with short progression-free survival and overall survival (OS) in multivariate analysis were +1q21, del(17p13) and an adverse immunoglobulin heavy chain gene (IGH) translocation group incorporating t(4;14), t(14;16) and t(14;20). These lesions frequently co-segregated, and there was an association between the accumulation of these adverse FISH lesions and a progressive impairment of survival. This observation was used to define a series of risk groups based on number of adverse lesions. Taking this approach, we defined a favorable risk group by the absence of adverse genetic lesions, an intermediate group with one adverse lesion and a high-risk group defined by the co-segregation of >1 adverse lesion. This genetic grouping was independent of the International Staging System (ISS) and so was integrated with the ISS to identify an ultra-high-risk group defined by ISS II or III and >1 adverse lesion. This group constituted 13.8% of patients and was associated with a median OS of 19.4 months.

Centromere strength provides the cell biological basis for meiotic drive and karyotype evolution in mice.

PubMed

Chmátal, Lukáš; Gabriel, Sofia I; Mitsainas, George P; Martínez-Vargas, Jessica; Ventura, Jacint; Searle, Jeremy B; Schultz, Richard M; Lampson, Michael A

2014-10-06

Mammalian karyotypes (number and structure of chromosomes) can vary dramatically over short evolutionary time frames. There are examples of massive karyotype conversion, from mostly telocentric (centromere terminal) to mostly metacentric (centromere internal), in 10(2)-10(5) years. These changes typically reflect rapid fixation of Robertsonian (Rb) fusions, a common chromosomal rearrangement that joins two telocentric chromosomes at their centromeres to create one metacentric. Fixation of Rb fusions can be explained by meiotic drive: biased chromosome segregation during female meiosis in violation of Mendel's first law. However, there is no mechanistic explanation of why fusions would preferentially segregate to the egg in some populations, leading to fixation and karyotype change, while other populations preferentially eliminate the fusions and maintain a telocentric karyotype. Here we show, using both laboratory models and wild mice, that differences in centromere strength predict the direction of drive. Stronger centromeres, manifested by increased kinetochore protein levels and altered interactions with spindle microtubules, are preferentially retained in the egg. We find that fusions preferentially segregate to the polar body in laboratory mouse strains when the fusion centromeres are weaker than those of telocentrics. Conversely, fusion centromeres are stronger relative to telocentrics in natural house mouse populations that have changed karyotype by accumulating metacentric fusions. Our findings suggest that natural variation in centromere strength explains how the direction of drive can switch between populations. They also provide a cell biological basis of centromere drive and karyotype evolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assembling the bacterial segrosome.

PubMed

Hayes, Finbarr; Barillà, Daniela

2006-05-01

Genome segregation in prokaryotes is a highly ordered process that integrates with DNA replication, cytokinesis and other fundamental facets of the bacterial cell cycle. The segrosome is the nucleoprotein complex that mediates DNA segregation in bacteria, its assembly and organization is best understood for plasmid partition. The recent elucidation of structures of the ParB plasmid segregation protein bound to centromeric DNA, and of the tertiary structures of other segregation proteins, are key milestones in the path to deciphering the molecular basis of bacterial DNA segregation.

The modelling of heat, mass and solute transport in solidification systems

NASA Technical Reports Server (NTRS)

Voller, V. R.; Brent, A. D.; Prakash, C.

1989-01-01

The aim of this paper is to explore the range of possible one-phase models of binary alloy solidification. Starting from a general two-phase description, based on the two-fluid model, three limiting cases are identified which result in one-phase models of binary systems. Each of these models can be readily implemented in standard single phase flow numerical codes. Differences between predictions from these models are examined. In particular, the effects of the models on the predicted macro-segregation patterns are evaluated.

City Space and Schools and Race: A Conceptual Safari into the Wilds of Urban Public Education and Its Geographic Role in Contemporary Urban Crises. Papers in Geography No. 9.

ERIC Educational Resources Information Center

Kuz, Anthony; Ziegler, Eugene L.

The thrust of this research exploration is aimed at one of the most pressing social problems facing America today: segregation in the public schools. The school system is only one of a complex set of systems, all interrelated, that comprise the entity that we call a city. The geography of the school system--the location of facilities and the…

Figure-ground segregation modulates apparent motion.

PubMed

Ramachandran, V S; Anstis, S

1986-01-01

We explored the relationship between figure-ground segmentation and apparent motion. Results suggest that: static elements in the surround can eliminate apparent motion of a cluster of dots in the centre, but only if the cluster and surround have similar "grain" or texture; outlines that define occluding surfaces are taken into account by the motion mechanism; the brain uses a hierarchy of precedence rules in attributing motion to different segments of the visual scene. Being designated as "figure" confers a high rank in this scheme of priorities.

The Spirit of OMERACT: Q Methodology Analysis of Conference Characteristics Valued by Delegates.

PubMed

Flurey, Caroline A; Kirwan, John R; Hadridge, Phillip; Richards, Pamela; Grosskleg, Shawna; Tugwell, Peter S

2015-10-01

To identify the major features of OMERACT meetings as valued by frequent participants and to explore whether there are groups of participants with different opinions. Using Q methodology (a qualitative and quantitative approach to grouping people according to subjective opinion), participants (who attended more than 1 OMERACT conference) sorted 66 statements relating to the "spirit of OMERACT" according to level of agreement across a normal distribution grid. Data were examined using Q factor analysis. Of 226 potential participants, 105 responded (46%). All participants highly ranked the focus on global standardization of methods, outcome measures, data-driven research, methodological discussion, and international collaboration. Four factors describing the "spirit of OMERACT" were identified: "Evidence not eminence" (n = 31) valued the data- and evidence-driven research above personality and status; "Collaboration and collegiality" (n = 19) valued the international and cross-stakeholder collaboration, interaction, and collegiality; "Equal voices, equal votes, common goals" (n = 12) valued equality in discussion and voting, with everyone striving toward the same goal; "principles and product, not process" (n = 8) valued the principles of focusing on outcome measures and the product of guiding clinical trials, but were unsure whether the process is necessary to reach this. The factors did not segregate different stakeholder groups. Delegates value different elements of OMERACT, and thus the "spirit of OMERACT" encompasses evidence-based research, collaboration, and equality, although a small group are unsure whether the process is necessary to achieve the end result. Q methodology may prove useful for conference organizers to identify their delegates' different needs to tailor conference content.

Stabilization of MgAl 2O 4 spinel surfaces via doping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasan, Md. M.; Dholabhai, Pratik P.; Castro, Ricardo H. R.

Here, the surface structure of complex oxides plays a vital role in processes such as sintering, thin film growth, and catalysis, as well as being a critical factor determining the stability of nanoparticles. We report atomistic calculations of the low-index stoichiometric magnesium aluminate spinel (MgAl 2O 4) surfaces, each with two different chemical terminations. High temperature annealing was used to explore the potential energy landscape and provide more stable surface structures. We find that the lowest energy surface is {100} while the highest energy surface is {111}. The surfaces were subsequently doped with three trivalent dopants (Y 3+, Gd 3+,more » La 3+) and one tetravalent dopant (Zr 4+) and both the surface segregation energies of the dopants and surface energies of the doped surface were determined. All of the dopants reduce the surface energy of spinel, though this reduction in energy depends on both the size and valence of the dopant. Dopants with larger ionic radius tend to segregate to the surface more strongly and reduce the surface energy to a greater extent. Furthermore, the ionic valence of the dopants seems to have a stronger influence on the segregation than does ionic size. For both undoped and doped spinel, the predicted crystal shape is dominated by {100} surfaces, but the relative fraction of the various surfaces changes with doping due to the unequal changes in energy, which has implications on equilibrium nanoparticle shapes and therefore on applications sensitive to surface properties.« less

Stabilization of MgAl2O4 spinel surfaces via doping

NASA Astrophysics Data System (ADS)

Hasan, Md. M.; Dholabhai, Pratik P.; Castro, Ricardo H. R.; Uberuaga, Blas P.

2016-07-01

Surface structure of complex oxides plays a vital role in processes such as sintering, thin film growth, and catalysis, as well as being a critical factor determining the stability of nanoparticles. Here, we report atomistic calculations of the low-index stoichiometric magnesium aluminate spinel (MgAl2O4) surfaces, each with two different chemical terminations. High temperature annealing was used to explore the potential energy landscape and provide more stable surface structures. We find that the lowest energy surface is {100} while the highest energy surface is {111}. The surfaces were subsequently doped with three trivalent dopants (Y3+, Gd3+, La3+) and one tetravalent dopant (Zr4+) and both the surface segregation energies of the dopants and surface energies of the doped surface were determined. All of the dopants reduce the surface energy of spinel, though this reduction in energy depends on both the size and valence of the dopant. Dopants with larger ionic radius tend to segregate to the surface more strongly and reduce the surface energy to a greater extent. Furthermore, the ionic valence of the dopants seems to have a stronger influence on the segregation than does ionic size. For both undoped and doped spinel, the predicted crystal shape is dominated by {100} surfaces, but the relative fraction of the various surfaces changes with doping due to the unequal changes in energy, which has implications on equilibrium nanoparticle shapes and therefore on applications sensitive to surface properties.

Stabilization of MgAl 2O 4 spinel surfaces via doping

DOE PAGES

Hasan, Md. M.; Dholabhai, Pratik P.; Castro, Ricardo H. R.; ...

2016-02-06

Here, the surface structure of complex oxides plays a vital role in processes such as sintering, thin film growth, and catalysis, as well as being a critical factor determining the stability of nanoparticles. We report atomistic calculations of the low-index stoichiometric magnesium aluminate spinel (MgAl 2O 4) surfaces, each with two different chemical terminations. High temperature annealing was used to explore the potential energy landscape and provide more stable surface structures. We find that the lowest energy surface is {100} while the highest energy surface is {111}. The surfaces were subsequently doped with three trivalent dopants (Y 3+, Gd 3+,more » La 3+) and one tetravalent dopant (Zr 4+) and both the surface segregation energies of the dopants and surface energies of the doped surface were determined. All of the dopants reduce the surface energy of spinel, though this reduction in energy depends on both the size and valence of the dopant. Dopants with larger ionic radius tend to segregate to the surface more strongly and reduce the surface energy to a greater extent. Furthermore, the ionic valence of the dopants seems to have a stronger influence on the segregation than does ionic size. For both undoped and doped spinel, the predicted crystal shape is dominated by {100} surfaces, but the relative fraction of the various surfaces changes with doping due to the unequal changes in energy, which has implications on equilibrium nanoparticle shapes and therefore on applications sensitive to surface properties.« less

Residential segregation and birth weight among racial and ethnic minorities in the United States.

PubMed

Walton, Emily

2009-12-01

Racial and ethnic minorities are often residentially segregated from whites in urban settings, a fact which has important health consequences. Research on the relationship between residential segregation and health outcomes lacks national-level investigation of racial and ethnic minority groups other than African Americans. I use multilevel analyses to examine the associations of residential isolation and clustering with birth weight among Asian, black, and Latino Americans using data from the National Center for Health Statistics' Natality Files and the U.S. Census. Findings indicate that segregation has a negative effect on the likelihood of having a low birth weight baby among Asian Americans, suggesting a possible concentration of social and structural resources in highly-segregated communities. On the contrary, segregation marginally increases the odds of low birth weight among African Americans, but only in the presence of higher poverty rates. Segregation does not affect birth weight among Latino Americans.

International Coordination of Exploring and Using Lunar Polar Volatiles

NASA Technical Reports Server (NTRS)

Gruener, J. E.; Suzuki, N. H.; Carpenter, J. D.

2016-01-01

Fourteen international space agencies are participating in the International Space Exploration Coordination Group (ISECG), working together to advance a long-range strategy for human and robotic space exploration beyond low earth orbit. The ISECG is a voluntary, non-binding international coordination mechanism through which individual agencies may exchange information regarding interests, objectives, and plans in space exploration with the goal of strengthening both individual exploration programs as well as the collective effort. The ISECG has developed a Global Exploration Roadmap (GER) that reflects the coordinated international dialog and continued preparation for exploration beyond low-Earth orbit, beginning with the Moon and cis-lunar space, and continuing to near-Earth asteroids, and Mars.

Framing Hostilities: Analysis of Mission Statements from Segregated Chicana/o Schools

ERIC Educational Resources Information Center

Orozco, Richard

2012-01-01

This study examined discourses used in mission statements from segregated Chicana/o and White schools. The words and phrases used in segregated Chicana/o school mission statements produce negatively oriented frames that make transparent low expectations and negative attitudes compared to those used in segregated White schools. These frames become…

"E Pluribus"... Separation: Deepening Double Segregation for More Students

ERIC Educational Resources Information Center

Orfield, Gary; Kucsera, John; Siegel-Hawley, Genevieve

2012-01-01

This report shows segregation has increased dramatically across the country for Latino students, who are attending more intensely segregated and impoverished schools than they have for generations. The segregation increases have been the most dramatic in the West. The typical Latino student in the region attends a school where less than a quarter…

43 CFR 2091.7-2 - Segregative effect and opening: Taylor Grazing Act.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregative effect and opening: Taylor Grazing Act. 2091.7-2 Section 2091.7-2 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.7-2 Segregative effect and opening: Taylor...

43 CFR 2091.7-1 - Segregative effect and opening: Classifications.

Code of Federal Regulations, 2011 CFR

2011-10-01

...: Classifications. 2091.7-1 Section 2091.7-1 Public Lands: Interior Regulations Relating to Public Lands (Continued... RULES Segregation and Opening of Lands § 2091.7-1 Segregative effect and opening: Classifications. (a)(1... authority of the Classification and Multiple Use Act (43 U.S.C. 1411-18) are segregated to the extent...

Aversive Racism and Intergroup Contact Theories: Cultural Competence in a Segregated World

ERIC Educational Resources Information Center

Rodenborg, Nancy A.; Boisen, Laura A.

2013-01-01

The United States remains highly segregated, and social work students are likely to live and work in segregated contexts. What implications does this have for their cultural competence? Does segregation affect social workers' ability to serve diverse clients without bias? This article reviews two social psychology theories, aversive racism…

Relationship between School and Residential Segregation at the Turn of the Century.

ERIC Educational Resources Information Center

Rickles, Jordan; Ong, Paul M.

This paper examines the relationship between school and residential segregation, noting that while these two forms of segregation are fundamentally linked, other factors cause them to diverge. The analysis focuses on segregation in 329 metropolitan areas. Data come from the 1998-99 National Center for Education Statistics Common Core of Data…

46 CFR 154.300 - Segregation of hold spaces from other spaces.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Segregation of hold spaces from other spaces. 154.300... Equipment Ship Arrangements § 154.300 Segregation of hold spaces from other spaces. Hold spaces must be segregated from machinery and boiler spaces, accommodation, service and control spaces, chain lockers...

46 CFR 154.300 - Segregation of hold spaces from other spaces.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Segregation of hold spaces from other spaces. 154.300... Equipment Ship Arrangements § 154.300 Segregation of hold spaces from other spaces. Hold spaces must be segregated from machinery and boiler spaces, accommodation, service and control spaces, chain lockers...

46 CFR 154.300 - Segregation of hold spaces from other spaces.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Segregation of hold spaces from other spaces. 154.300... Equipment Ship Arrangements § 154.300 Segregation of hold spaces from other spaces. Hold spaces must be segregated from machinery and boiler spaces, accommodation, service and control spaces, chain lockers...

46 CFR 154.300 - Segregation of hold spaces from other spaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Segregation of hold spaces from other spaces. 154.300... Equipment Ship Arrangements § 154.300 Segregation of hold spaces from other spaces. Hold spaces must be segregated from machinery and boiler spaces, accommodation, service and control spaces, chain lockers...

46 CFR 154.300 - Segregation of hold spaces from other spaces.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Segregation of hold spaces from other spaces. 154.300... Equipment Ship Arrangements § 154.300 Segregation of hold spaces from other spaces. Hold spaces must be segregated from machinery and boiler spaces, accommodation, service and control spaces, chain lockers...

43 CFR 3210.10 - When does lease segregation occur?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false When does lease segregation occur? 3210.10 Section 3210.10 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Lease Information § 3210.10 When does lease segregation occur? (a) Lease segregation occurs when: (1) A...

Are We Segregated and Satisfied? Segregation and Inequality in Southern California Schools

ERIC Educational Resources Information Center

Kucsera, John V.; Siegel-Hawley, Genevieve; Orfield, Gary

2015-01-01

Southern California is facing a demographic transformation that will become characteristic of the nation as a whole in coming decades. In this research, we present a historical review of the region's attempt to address school inequity, recent enrollment and segregation trends, and an investigation of whether segregation still matters. Our results…

17 CFR 31.7 - Maintenance of minimum financial, cover and segregation requirements by leverage transaction...

Code of Federal Regulations, 2010 CFR

2010-04-01

... financial, cover and segregation requirements by leverage transaction merchants. 31.7 Section 31.7 Commodity... of minimum financial, cover and segregation requirements by leverage transaction merchants. (a) Each... required by § 31.8, or that the amount of leverage customer funds in segregation is less than is required...

43 CFR 2611.2 - Period of segregation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Period of segregation. 2611.2 Section 2611..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) CAREY ACT GRANTS Segregation Under the Carey Act: Procedures § 2611.2 Period of segregation. (a) The States are allowed 10 years from the date of the signing...

28 CFR 540.16 - Inmate correspondence while in segregation and holdover status.

Code of Federal Regulations, 2010 CFR

2010-07-01

... segregation and holdover status. 540.16 Section 540.16 Judicial Administration BUREAU OF PRISONS, DEPARTMENT... Inmate correspondence while in segregation and holdover status. (a) The Warden shall permit an inmate in... those of other inmates insofar as practical. (b) The Warden shall permit an inmate in segregation to...

28 CFR 540.16 - Inmate correspondence while in segregation and holdover status.

Code of Federal Regulations, 2011 CFR

2011-07-01

... segregation and holdover status. 540.16 Section 540.16 Judicial Administration BUREAU OF PRISONS, DEPARTMENT... Inmate correspondence while in segregation and holdover status. (a) The Warden shall permit an inmate in... those of other inmates insofar as practical. (b) The Warden shall permit an inmate in segregation to...

43 CFR 2091.9 - Segregation and opening resulting from laws specific to Alaska.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening resulting from laws specific to Alaska. 2091.9 Section 2091.9 Public Lands: Interior Regulations Relating to Public...) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.9 Segregation and opening resulting from...

17 CFR 31.7 - Maintenance of minimum financial, cover and segregation requirements by leverage transaction...

Code of Federal Regulations, 2011 CFR

2011-04-01

... financial, cover and segregation requirements by leverage transaction merchants. 31.7 Section 31.7 Commodity... of minimum financial, cover and segregation requirements by leverage transaction merchants. (a) Each... required by § 31.8, or that the amount of leverage customer funds in segregation is less than is required...

43 CFR 2091.2-1 - Segregation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation. 2091.2-1 Section 2091.2-1..., DEPARTMENT OF THE INTERIOR LAND RESOURCE MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.2-1 Segregation. The publication of a Notice of Realty Action in the Federal Register...

43 CFR 3873.1 - Segregation of mineral from non-mineral land.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Segregation of mineral from non-mineral...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ADVERSE CLAIMS, PROTESTS AND CONFLICTS Segregation § 3873.1 Segregation of mineral from non-mineral land. Where a survey is...

43 CFR 3873.1 - Segregation of mineral from non-mineral land.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Segregation of mineral from non-mineral...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ADVERSE CLAIMS, PROTESTS AND CONFLICTS Segregation § 3873.1 Segregation of mineral from non-mineral land. Where a survey is...

43 CFR 3873.1 - Segregation of mineral from non-mineral land.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Segregation of mineral from non-mineral...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) ADVERSE CLAIMS, PROTESTS AND CONFLICTS Segregation § 3873.1 Segregation of mineral from non-mineral land. Where a survey is...

Ionic Segregation on Grain Boundaries in Thermally Grown Alumina Scales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pint, Bruce A; Unocic, Kinga A

2012-01-01

This study first examined segregation behaviour in the alumina scale formed after 100 h at 1100 C on bare and MCrAlYHfSi-coated single-crystal superalloys with {approx}10 ppma La and Y. For the bare superalloy, Hf and Ti were detected on the grain boundaries of the inner columnar alumina layer. Increasing the oxidation temperature to 1200 C for 2 h did not change the segregation behavior. With the bond coating, both Y and Hf were segregated to the grain boundaries as expected. However, there was evidence of Ti-rich oxide particles near the gas interface suggesting that Ti diffused from the superalloy throughmore » the coating. To further understand these segregation observations with multiple dopants, other alumina-forming systems were examined. Alumina scale grain boundary co-segregation of Ti with Y is common for FeCrAl alloys. Co-segregation of Hf and Ti was observed in the scale formed on co-doped NiAl. No La segregation was detected in the scale formed on NiCrAl with only a 19 ppma La addition, however, the scale was adherent.« less

Segregation simulation of binary granular matter under horizontal pendulum vibrations

NASA Astrophysics Data System (ADS)

Ma, Xuedong; Zhang, Yanbing; Ran, Heli; Zhang, Qingying

2016-08-01

Segregation of binary granular matter with different densities under horizontal pendulum vibrations was investigated through numerical simulation using a 3D discrete element method (DEM). The particle segregation mechanism was theoretically analyzed using gap filling, momentum and kinetic energy. The effect of vibrator geometry on granular segregation was determined using the Lacey mixing index. This study shows that dynamic changes in particle gaps under periodic horizontal pendulum vibrations create a premise for particle segregation. The momentum of heavy particles is higher than that of light particles, which causes heavy particles to sink and light particles to float. With the same horizontal vibration parameters, segregation efficiency and stability, which are affected by the vibrator with a cylindrical convex geometry, are superior to that of the original vibrator and the vibrator with a cross-bar structure. Moreover, vibrator geometry influences the segregation speed of granular matter. Simulation results of granular segregation by using the DEM are consistent with the final experimental results, thereby confirming the accuracy of the simulation results and the reliability of the analysis.

More reliable inference for the dissimilarity index of segregation

PubMed Central

Allen, Rebecca; Burgess, Simon; Davidson, Russell; Windmeijer, Frank

2015-01-01

Summary The most widely used measure of segregation is the so‐called dissimilarity index. It is now well understood that this measure also reflects randomness in the allocation of individuals to units (i.e. it measures deviations from evenness, not deviations from randomness). This leads to potentially large values of the segregation index when unit sizes and/or minority proportions are small, even if there is no underlying systematic segregation. Our response to this is to produce adjustments to the index, based on an underlying statistical model. We specify the assignment problem in a very general way, with differences in conditional assignment probabilities underlying the resulting segregation. From this, we derive a likelihood ratio test for the presence of any systematic segregation, and bias adjustments to the dissimilarity index. We further develop the asymptotic distribution theory for testing hypotheses concerning the magnitude of the segregation index and show that the use of bootstrap methods can improve the size and power properties of test procedures considerably. We illustrate these methods by comparing dissimilarity indices across school districts in England to measure social segregation. PMID:27774035

Study of the Formation Mechanism of A-Segregation Based on Microstructural Morphology

NASA Astrophysics Data System (ADS)

Zhang, Zhao; Bao, Yuchong; Liu, Lin; Pian, Song; Li, Ri

2018-04-01

A model that combines a cellular automaton (CA) and lattice Boltzmann method (LBM) is presented. The mechanism of A-segregation in an Fe-0.34 wt pct C alloy ingot is analyzed on the basis of microstructural morphology calculations. The CA is used to capture the solid/liquid interface, while the LBM is used to calculate the transport phenomena. (1) The solidification of global columnar dendrites was simulated, and two obvious A-segregation bands appeared in the middle-radius region between the ingot wall surface and the centerline. In addition, the angle of deflection to the centerline increased with the increasing heat dissipation rate of the wall surface. When natural convection was ignored, the A-segregation disappeared, and only positive segregation was present in the center and bottom corner of the ingot. (2) Mixed columnar-equiaxed solidification was simulated. Many A-segregation bands appeared in the ingot. (3) Global equiaxed solidification was simulated, and no A-segregation bands were found. The results show that the upward movement of the high-concentration melt is the key to the formation of A-segregation bands, and remelting and the emergence of equiaxed grains are not necessary conditions to develop these bands. However, the appearance of equiaxed grains accelerates the formation of vortexes; thus, many A-segregation bands appear during columnar-equiaxed solidification.

Mechanisms of time-based figure-ground segregation.

PubMed

Kandil, Farid I; Fahle, Manfred

2003-11-01

Figure-ground segregation can rely on purely temporal information, that is, on short temporal delays between positional changes of elements in figure and ground (Kandil, F.I. & Fahle, M. (2001) Eur. J. Neurosci., 13, 2004-2008). Here, we investigate the underlying mechanisms by measuring temporal segregation thresholds for various kinds of motion cues. Segregation can rely on monocular first-order motion (based on luminance modulation) and second-order motion cues (contrast modulation) with a high temporal resolution of approximately 20 ms. The mechanism can also use isoluminant motion with a reduced temporal resolution of 60 ms. Figure-ground segregation can be achieved even at presentation frequencies too high for human subjects to inspect successive frames individually. In contrast, when stimuli are presented dichoptically, i.e. separately to both eyes, subjects are unable to perceive any segregation, irrespective of temporal frequency. We propose that segregation in these displays is detected by a mechanism consisting of at least two stages. On the first level, standard motion or flicker detectors signal local positional changes (flips). On the second level, a segregation mechanism combines the local activities of the low-level detectors with high temporal precision. Our findings suggest that the segregation mechanism can rely on monocular detectors but not on binocular mechanisms. Moreover, the results oppose the idea that segregation in these displays is achieved by motion detectors of a higher order (motion-from-motion), but favour mechanisms sensitive to short temporal delays even without activation of higher-order motion detectors.

Evolutionary dynamics of adult stem cells: comparison of random and immortal-strand segregation mechanisms.

PubMed

Tannenbaum, Emmanuel; Sherley, James L; Shakhnovich, Eugene I

2005-04-01

This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) "immortal DNA strand" co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

Evolutionary dynamics of adult stem cells: Comparison of random and immortal-strand segregation mechanisms

NASA Astrophysics Data System (ADS)

Tannenbaum, Emmanuel; Sherley, James L.; Shakhnovich, Eugene I.

2005-04-01

This paper develops a point-mutation model describing the evolutionary dynamics of a population of adult stem cells. Such a model may prove useful for quantitative studies of tissue aging and the emergence of cancer. We consider two modes of chromosome segregation: (1) random segregation, where the daughter chromosomes of a given parent chromosome segregate randomly into the stem cell and its differentiating sister cell and (2) “immortal DNA strand” co-segregation, for which the stem cell retains the daughter chromosomes with the oldest parent strands. Immortal strand co-segregation is a mechanism, originally proposed by [Cairns Nature (London) 255, 197 (1975)], by which stem cells preserve the integrity of their genomes. For random segregation, we develop an ordered strand pair formulation of the dynamics, analogous to the ordered strand pair formalism developed for quasispecies dynamics involving semiconservative replication with imperfect lesion repair (in this context, lesion repair is taken to mean repair of postreplication base-pair mismatches). Interestingly, a similar formulation is possible with immortal strand co-segregation, despite the fact that this segregation mechanism is age dependent. From our model we are able to mathematically show that, when lesion repair is imperfect, then immortal strand co-segregation leads to better preservation of the stem cell lineage than random chromosome segregation. Furthermore, our model allows us to estimate the optimal lesion repair efficiency for preserving an adult stem cell population for a given period of time. For human stem cells, we obtain that mispaired bases still present after replication and cell division should be left untouched, to avoid potentially fixing a mutation in both DNA strands.

A reference genetic map of C. clementina hort. ex Tan.; citrus evolution inferences from comparative mapping

PubMed Central

2012-01-01

Background Most modern citrus cultivars have an interspecific origin. As a foundational step towards deciphering the interspecific genome structures, a reference whole genome sequence was produced by the International Citrus Genome Consortium from a haploid derived from Clementine mandarin. The availability of a saturated genetic map of Clementine was identified as an essential prerequisite to assist the whole genome sequence assembly. Clementine is believed to be a ‘Mediterranean’ mandarin × sweet orange hybrid, and sweet orange likely arose from interspecific hybridizations between mandarin and pummelo gene pools. The primary goals of the present study were to establish a Clementine reference map using codominant markers, and to perform comparative mapping of pummelo, sweet orange, and Clementine. Results Five parental genetic maps were established from three segregating populations, which were genotyped with Single Nucleotide Polymorphism (SNP), Simple Sequence Repeats (SSR) and Insertion-Deletion (Indel) markers. An initial medium density reference map (961 markers for 1084.1 cM) of the Clementine was established by combining male and female Clementine segregation data. This Clementine map was compared with two pummelo maps and a sweet orange map. The linear order of markers was highly conserved in the different species. However, significant differences in map size were observed, which suggests a variation in the recombination rates. Skewed segregations were much higher in the male than female Clementine mapping data. The mapping data confirmed that Clementine arose from hybridization between ‘Mediterranean’ mandarin and sweet orange. The results identified nine recombination break points for the sweet orange gamete that contributed to the Clementine genome. Conclusions A reference genetic map of citrus, used to facilitate the chromosome assembly of the first citrus reference genome sequence, was established. The high conservation of marker order observed at the interspecific level should allow reasonable inferences of most citrus genome sequences by mapping next-generation sequencing (NGS) data in the reference genome sequence. The genome of the haploid Clementine used to establish the citrus reference genome sequence appears to have been inherited primarily from the ‘Mediterranean’ mandarin. The high frequency of skewed allelic segregations in the male Clementine data underline the probable extent of deviation from Mendelian segregation for characters controlled by heterozygous loci in male parents. PMID:23126659

The effect of segregation on the austemper transformation and toughness of ductile irons

NASA Astrophysics Data System (ADS)

Lin, B. Y.; Chen, E. T.; Lei, T. S.

1998-06-01

The effect of segregation of alloying elements on the phase transformation of ductile iron during austempering was investigated. Four heats, each containing 0.4%Mn, 1% Cu, 1.5% Ni, or 0.4% Mo (wt%) separately, were melted; then three different sizes of casting bars (3,15, and 75 mm diameter) were poured from each heat. The distribution and the degree of segregation of certain elements were quantitatively analyzed using an electron microprobe. A personal computer (PC)-controlled heat treating system was used to measure electrical resistivity, and the information on resistivity variations was used to analyze the effect of segregation on phase transformations during austempering. Also, Charpy impact and Rockwell hardness tests were performed to determine the effect of segregation on properties. Results of the electron microprobe analysis showed that the degree of segregation of alloy elements increases with an increase in diameter of the casting bars (i.e., an increase of solidification time of castings). The degree of segregation of alloy elements, represented by segregation ratio (SR) (the maximum concentration of element in cell divided by the minimum concentration of element in cell), varied linearly with the casting modulus (M) (volume of casting divided by surface area of casting). Regarding the segregating tendency among alloy elements, positive segregating elements Mn and Mo showed more segregation than the negative segregating elements Si, Cu, and Ni. In addition, segregation of Mo was more significant than Mn, and that for Cu was greater than Ni and Si. Between the time of finishing the first stage and beginning the second stage of bainite reaction in ductile irons, there is a significant “processing window,” At;, for austempering to obtain optimum mechanical properties. From the electrical resistivity data, it was observed that the austempering temperature plays a major role in the processing window. There was a narrow window at 400 ‡C but a larger one at 350 ‡C. Additionally, the microsegregation of alloying elements led to variation of the time of phase transformation for various regions in the grain cells of ductile iron which caused the processing window to decrease. The span of the processing window decreased with an increase in degree of segregation. There was no significant difference in the hardness of the alloys in various diameter specimens. However, the impact toughness was significantly affected by the segregation. The impact values in 15 mm specimens with less degree of segregation were greater than those in 75 mm specimens with significant segregation. The Ni, Cu, and Mn alloys that were austempered to complete the first stage of bainite formation had approximately the same impact values for all diameter samples. The Mo alloy upon austempering produced no bainite, but it had much untransformed retained austenite in the intercellular regions and, therefore, had lower impact values.

Informational and Normative Influences in Conformity from a Neurocomputational Perspective.

PubMed

Toelch, Ulf; Dolan, Raymond J

2015-10-01

We consider two distinct influences that drive conformity behaviour. Whereas informational influences facilitate adaptive and accurate responses, normative influences bias decisions to enhance social acceptance. We explore these influences from a perspective of perceptual and value-based decision-making models and apply these models to classical works on conformity. We argue that an informational account predicts a surprising tendency to conform. Moreover, we detail how normative influences fit into this framework and interact with social influences. Finally, we explore potential neuronal substrates for informational and normative influences based on a consideration of the neurobiological literature, highlighting conceptual shortcomings particularly with regard to a failure to segregate informational and normative influences. Copyright © 2015 Elsevier Ltd. All rights reserved.

Segregation Levels in Cleveland Public Schools and the Cleveland Voucher Program. School Choice Issues in the State

ERIC Educational Resources Information Center

Forster, Greg

2006-01-01

Examining the widespread claims that private schools have high segregation levels and vouchers will lead to greater segregation, this study finds that both assertions are empirically unsupportable. Private schools participating in Cleveland's voucher program are much less segregated than Cleveland's public schools. This means that students using…

The Big Disconnect between Segregation and Integration

ERIC Educational Resources Information Center

Verdun, Vincene

2005-01-01

The hearts and minds of the American people have been won over on the issue of segregation. However, the dilemma is that while an overwhelming majority of Americans would cringe at the idea of a racially segregated America, America remains racially segregated and racial equality is more ideal than real. Even though there is almost no legal…

Racial Segregation and Educational Outcomes in Metropolitan Boston. Metro Boston Equity Initiative. Issue Summary No.6

ERIC Educational Resources Information Center

Lee, Chungmei

2004-01-01

This report takes a look at the issues concerning racial segregation and educational outcomes in Metropolitan Boston. Despite the fact that metro Boston is overwhelmingly white, its public schools are highly segregated by race and language. Segregated minority schools in metro Boston are profoundly unequal, with high poverty levels, with lower…

43 CFR 2091.5-4 - Segregative effect and opening: Water power withdrawals.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Segregative effect and opening: Water power withdrawals. 2091.5-4 Section 2091.5-4 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.5-4 Segregative effect and opening: Water power...

43 CFR 2091.5-4 - Segregative effect and opening: Water power withdrawals.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Segregative effect and opening: Water power withdrawals. 2091.5-4 Section 2091.5-4 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.5-4 Segregative effect and opening: Water power...

43 CFR 2091.5-4 - Segregative effect and opening: Water power withdrawals.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Segregative effect and opening: Water power withdrawals. 2091.5-4 Section 2091.5-4 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.5-4 Segregative effect and opening: Water power...

Gender Segregation in Nursery School: Predictors and Outcomes.

ERIC Educational Resources Information Center

Maccoby, Eleanor E.; Jacklin, Carol Nagy

Sex segregation is a powerful phenomenon in childhood. It occurs universally whenever children have a choice of playmates and is found in sub-human primates too. Adults are not directly responsible for sex segregation. Data do not support the hypothesis that the most ladylike girls and the most rough and active boys first form the segregated play…

Segregation, Desegregation, Segregation: Charter School Options as a Return to Separate and Unequal Schools for Urban Families

ERIC Educational Resources Information Center

Chapman, Thandeka K.

2018-01-01

The controversial glory of the "Brown" decisions and the retraction of court-ordered reforms represent the limited gains of racial justice in education and the protection of white privilege through law and policy. The return to segregation, as propagated through the rise of racially and economically segregated charter schools, exhibits…

75 FR 444 - Notice of Realty Action: Direct Sale of Public Lands in Tehama County, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-05

... segregated from appropriation under the public land laws, including the mining laws. The segregation terminates upon issuance of a patent, publication in the Federal Register of a termination of the segregation, or 2 years from the date of segregation, whichever occurs first. The lands will not be sold until at...

43 CFR 2091.7 - Segregation and opening of lands classified for a specific use.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening of lands classified for a specific use. 2091.7 Section 2091.7 Public Lands: Interior Regulations Relating to Public...) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.7 Segregation and opening of lands...

43 CFR 2091.2 - Segregation and opening resulting from publication of a Notice of Realty Action.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening resulting from publication of a Notice of Realty Action. 2091.2 Section 2091.2 Public Lands: Interior Regulations Relating to... (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.2 Segregation and opening...

43 CFR 2091.4-2 - Segregation and opening: Airport leases and grants.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening: Airport leases and grants. 2091.4-2 Section 2091.4-2 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.4-2 Segregation and opening: Airport leases and...

77 FR 71568 - Capital, Margin, and Segregation Requirements for Security-Based Swap Dealers and Major Security...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-03

... [Release No. 34-68071A; File No. S7-08-12] RIN 3235-AL12 Capital, Margin, and Segregation Requirements for... participants (``MSBSPs''), segregation requirements for SBSDs, and notification requirements with respect to segregation for SBSDs and MSBSPs, as well as increases to the minimum net capital requirements for broker...

The Complex Determinants of School Intake Characteristics and Segregation, England 1989 to 2014

ERIC Educational Resources Information Center

Gorard, Stephen

2016-01-01

The extent of between-school segregation, or clustering of disadvantaged students within schools, in England varies depending on the indicator of interest. For example, the trend over time for segregation by student poverty differs from those for ethnicity or special educational need. Additionally the causes of the level of segregation for any…

43 CFR 2091.4-3 - Segregation and opening: Carey Act.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening: Carey Act. 2091.4-3 Section 2091.4-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF... Segregation and Opening of Lands § 2091.4-3 Segregation and opening: Carey Act. (a) For lands covered by a...

43 CFR 2091.4-1 - Segregation and opening: Desert-land entries and Indian allotments.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening: Desert-land entries and Indian allotments. 2091.4-1 Section 2091.4-1 Public Lands: Interior Regulations Relating to... (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.4-1 Segregation and opening...

46 CFR 148.145 - Stowage and segregation for materials of Class 7.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation for materials of Class 7. 148... CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.145 Stowage and segregation for materials of Class 7. (a) Class 7 material listed in Table 148.10 of this part...

43 CFR 3107.3-2 - Segregation of leases committed in part.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation of leases committed in part... Continuation, Extension or Renewal § 3107.3-2 Segregation of leases committed in part. Any lease committed... term of the lease or for 2 years from the date of segregation, whichever is longer. However, for any...

43 CFR 2091.3 - Segregation and opening resulting from a proposal or application.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening resulting from a proposal or application. 2091.3 Section 2091.3 Public Lands: Interior Regulations Relating to Public Lands... LAWS AND RULES Segregation and Opening of Lands § 2091.3 Segregation and opening resulting from a...

43 CFR 2091.4-2 - Segregation and opening: Airport leases and grants.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Segregation and opening: Airport leases... LAWS AND RULES Segregation and Opening of Lands § 2091.4-2 Segregation and opening: Airport leases and grants. (a) The issuance of a lease for airport purposes under the authority of the Act of May 24, 1928...

43 CFR 2091.4-2 - Segregation and opening: Airport leases and grants.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Segregation and opening: Airport leases... LAWS AND RULES Segregation and Opening of Lands § 2091.4-2 Segregation and opening: Airport leases and grants. (a) The issuance of a lease for airport purposes under the authority of the Act of May 24, 1928...

43 CFR 2091.4-2 - Segregation and opening: Airport leases and grants.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Segregation and opening: Airport leases... LAWS AND RULES Segregation and Opening of Lands § 2091.4-2 Segregation and opening: Airport leases and grants. (a) The issuance of a lease for airport purposes under the authority of the Act of May 24, 1928...

Post-Slavery? Post-Segregation? Post-Racial? A History of the Impact of Slavery, Segregation, and Racism on the Education of African Americans

ERIC Educational Resources Information Center

Span, Christopher M.

2015-01-01

This chapter details how slavery, segregation, and racism impacted the educational experiences of African Americans from the colonial era to the present. It argues that America has yet to be a truly post-slavery and post-segregation society, let alone a post-racial society.

Residential segregation, health behavior and overweight/obesity among a national sample of African American adults.

PubMed

Corral, Irma; Landrine, Hope; Hao, Yongping; Zhao, Luhua; Mellerson, Jenelle L; Cooper, Dexter L

2012-04-01

We examined the role of residential segregation in 5+ daily fruit/vegetable consumption, exercise, and overweight/obesity among African Americans by linking data on the 11,142 African American adults in the 2000 Behavioral Risk Factor Surveillance System to 2000 census data on the segregation of metropolitan statistical areas (MSAs). Multi-level modeling revealed that after controlling for individual-level variables, MSA Segregation and Poverty contributed to fruit/vegetable consumption, MSA Poverty alone contributed to exercise, and MSA Segregation alone contributed to overweight/obesity. These findings highlight the need for research on the built-environments of the segregated neighborhoods in which most African Americans reside, and suggest that neighborhood disparities may contribute to health disparities.

Taxa and names in Cynoglossum sensu lato (Boraginaceae, Cynoglosseae): an annotated, synonymic inventory, with links to the protologues and mention of original material

PubMed Central

Stier, Victoria

2015-01-01

Abstract Background An inventory is presented of all names so far validly published in Cynoglossum sensu lato and its segregate genera: Adelocaryum, Afrotysonia, Kuschakewiczia, Lindelofia, Mattiastrum, Paracaryum, Rindera, Solenanthus, Trachelanthus, and their synonyms. Names and designations that were not validly published in the cited place, and later isonyms, are accounted for when they have been included in the International Plant Name Index (IPNI). Problems with IPNI entries, including errors and omissions, are discussed, and the hope is expressed that the present inventory may be of use for fixing them. New information The inventory, generated from a list of structured data, is presented in two Supplements, as a searchable HTML document comprising a sequence of entries with internal cross-links and links to external sources, in particular to protologues accessible online or, copyright restrictions permitting, made available as scanned documents via DOIs, and as machine-readible file. With minor exceptions, all names have been verified in their original place of publication, and all were nomenclaturally assessed. Colour coding is used to distinguish between names (in green) pertaining to Cynoglossum sensu lato, for which complete synonymies are provided; and names (in orange) pertaining to other genera but published under Cynoglossum or its segregates. They are listed together with their basionym and the corresponding correct name (if it exists), but without complete synonymy. Acceptable, potentially correct names appear in bold-face type, both under a broadly defined Cynoglossum (for which purpose validation of 81 new combinations and the name of 1 new species was necessary) and under one or more of its segregates. When a name was published for a new taxon, original material is indicated, usually by direct quotation from the protologue. New type designations are exceptional (two cases), whereas former type designations are cited whenever known. Furthermore, types and original specimens, especially when their digital images are available online, are mentioned with their locations and accession numbers. Comments are added whenever appropriate, especially to explain nomenclatural assessments that are not self-evident. PMID:25941451

The Effect of Strict Segregation on Pseudomonas aeruginosa in Cystic Fibrosis Patients

PubMed Central

van Mansfeld, Rosa; de Vrankrijker, Angelica; Brimicombe, Roland; Heijerman, Harry; Teding van Berkhout, Ferdinand; Spitoni, Cristian; Grave, Sanne; van der Ent, Cornelis; Wolfs, Tom; Willems, Rob; Bonten, Marc

2016-01-01

Introduction Segregation of patients with cystic fibrosis (CF) was implemented to prevent chronic infection with epidemic Pseudomonas aeruginosa strains with presumed detrimental clinical effects, but its effectiveness has not been carefully evaluated. Methods The effect of strict segregation on the incidence of P. aeruginosa infection in CF patients was investigated through longitudinal protocolized follow-up of respiratory tract infection before and after segregation. In two nested cross-sectional studies in 2007 and 2011 the P. aeruginosa population structure was investigated and clinical parameters were determined in patients with and without infection with the Dutch epidemic P. aeruginosa clone (ST406). Results Of 784 included patients 315 and 382 were at risk for acquiring chronic P. aeruginosa infection before and after segregation. Acquisition rates were, respectively, 0.14 and 0.05 per 1,000 days at risk (HR: 0.66, 95% CI [0.2548–1.541]; p = 0.28). An exploratory subgroup analysis indicated lower acquisition after segregation in children < 15 years of age (HR: 0.43, 95% CI[0.21–0.95]; p = 0.04). P. aeruginosa population structure did not change after segregation and ST406 was not associated with lung function decline, death or lung transplantation. Conclusions Strict segregation was not associated with a statistically significant lower acquisition of chronic P. aeruginosa infection and ST406 was not associated with adverse clinical outcome. After segregation there were no new acquisitions of ST406. In an unplanned exploratory analysis chronic acquisition of P. aeruginosa was lower after implementation of segregation in patients under 15 years of age. PMID:27280467

Racial/ethnic residential segregation, neighborhood poverty and urinary biomarkers of diet in New York City adults.

PubMed

Yi, Stella S; Ruff, Ryan R; Jung, Molly; Waddell, Elizabeth Needham

2014-12-01

Consuming less sodium and more potassium are components of a healthy diet and reduced cardiovascular disease risk. Racial/ethnic segregation and poverty are both associated with dietary habits, but data linking dietary intake to neighborhood characteristics are limited, particularly in Hispanic and Asian American ethnic enclaves. This study presents relationships between neighborhood-level segregation, poverty and biologic indicators of sodium and potassium consumption. Data were from the 2010 Heart Follow-Up Study, a cross-sectional health survey, which included 24-h urine collections and self-reported health status (n = 1656). Black, Hispanic, and Asian segregated areas and neighborhood poverty were defined for aggregated zip-code areas. Multivariable models assessed the association between neighborhood segregation and poverty and sodium and potassium intake, after adjustment for individual-level covariates. In unadjusted models, potassium intake (a marker of fruit and vegetable consumption) was lower in high-versus low-Hispanic segregated neighborhoods, and the sodium-potassium ratio was higher in high-versus low black and Hispanic segregated neighborhoods, and in high-versus low-poverty neighborhoods; the sodium-potassium ratio was lower in high-versus low Asian segregated neighborhoods. Segregation and poverty were not independently associated with nutrition biomarkers after adjustment for demographics and for each other; however, practical consideration of neighborhood race/ethnic composition may be useful to understand differences in consumption. Copyright © 2014 Elsevier Ltd. All rights reserved.

Do Strict Land Use Regulations Make Metropolitan Areas More Segregated by Income?

PubMed Central

Lens, Michael C.; Monkkonen, Paavo

2018-01-01

Problem, research strategy, and findings Income segregation has risen in each of the last four decades in U.S. metropolitan areas, which can have lifelong impacts on the health, economic productivity, and behaviors of residents. Although it is widely assumed that local land use regulations—such as minimum lot sizes and growth controls—exclude low-income households from wealthier neighborhoods, the empirical research is surprisingly limited. We examine the relationship between land use regulation and segregation by income using new measures for the 95 biggest cities in the United States. We find that density restrictions are associated with the segregation of the wealthy and middle income, but not the poor. We also find that more local pressure to regulate land use is linked to higher rates of income segregation, but that more state control is connected to lower-income segregation. Takeaway for practice Density restrictions do drive urban income segregation of the rich, not the poor, but should be addressed because rich enclaves create significant metropolitan problems. Planners at the local level need assistance from regional and state efforts to ameliorate income segregation. Inclusionary housing requirements have a greater potential to reduce income segregation than bringing higher-income households into lower-income parts of the city. Finally, comprehensive and consistent data on the impacts of local land use regulations should be collected to inform future research and planning practice. PMID:29422701

Freedom from Racial Barriers: The Empirical Evidence on Vouchers and Segregation. School Choice Issues in Depth

ERIC Educational Resources Information Center

Forster, Greg

2006-01-01

This report collects the results of all available studies using valid empirical methods to compare segregation in public and private schools, both in general and in the context of school voucher programs. Examining the widespread claims that private schools have high segregation levels and vouchers will lead to greater segregation, this report…

Parental Choice in the Netherlands: Growing Concerns about Segregation. Sanford Working Paper Series. SAN10-02

ERIC Educational Resources Information Center

Ladd, Helen F.; Fiske, Edward B.; Ruijs, Nienke

2010-01-01

The Netherlands has a long history of parental choice and school anatomy. This paper examines why segregation by educational disadvantage has only recently emerged as a policy issue in the Netherlands. In addition, we document the levels and trends of school segregation in Dutch cities. We find segregation levels that are high both absolutely and…

The Sense of Place behind Segregating Practices: An Ethnographic Approach to the Symbolic Partitioning of Metro Manila

ERIC Educational Resources Information Center

Garrido, Marco

2013-01-01

The literature on cities in the developing world equates segregation with the proliferation of enclaves and slums and tends to overlook how the people associated with those places are further segregated in public spaces and enclaves. To account for the symbolic partitioning of Metro Manila, I document the segregating practices of the residents of…

46 CFR 148.130 - Stowage and segregation for materials of Class 4.2.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation for materials of Class 4.2. 148... CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.130 Stowage and segregation for materials of Class 4.2. (a) Class 4.2 materials listed in Table 148.10 of this...

77 FR 7601 - Notice of Segregation of Public Lands for the Pattern Energy Group Ocotillo Express Wind Energy...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-13

... LVRWB10B3980] Notice of Segregation of Public Lands for the Pattern Energy Group Ocotillo Express Wind Energy...) application for the Ocotillo Express Wind Project. The public land contained in this segregation totals approximately 12,436 acres. DATES: Effective Date: This segregation is effective on February 13, 2012. FOR...

46 CFR 148.140 - Stowage and segregation for materials of Class 5.1.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation for materials of Class 5.1. 148... CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.140 Stowage and segregation for materials of Class 5.1. (a) Class 5.1 materials listed in Table 148.10 of this...

46 CFR 148.135 - Stowage and segregation for materials of Class 4.3.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation for materials of Class 4.3. 148... CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.135 Stowage and segregation for materials of Class 4.3. (a) Class 4.3 materials listed in Table 148.10 of this...

46 CFR 148.125 - Stowage and segregation for materials of Class 4.1.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Stowage and segregation for materials of Class 4.1. 148... CARGOES CARRIAGE OF BULK SOLID MATERIALS THAT REQUIRE SPECIAL HANDLING Stowage and Segregation § 148.125 Stowage and segregation for materials of Class 4.1. (a) Class 4.1 materials listed in Table 148.10 of this...

43 CFR 2091.4 - Segregation and opening resulting from the allowance of entries, leases, grants or contracts.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregation and opening resulting from the allowance of entries, leases, grants or contracts. 2091.4 Section 2091.4 Public Lands: Interior Regulations... MANAGEMENT (2000) SPECIAL LAWS AND RULES Segregation and Opening of Lands § 2091.4 Segregation and opening...

Do Irregularly Shaped School Attendance Zones Contribute to Racial Segregation or Integration?

PubMed Central

Saporito, Salvatore; Van Riper, David

2017-01-01

This research investigates if and how much the shapes of school attendance zones contribute to racial segregation in schools. We find that the typical school attendance zone is relatively compact and resembles a square-like shape. Compact zones typically draw children from local residential areas, and since local areas are often racially homogeneous, this suggests that high levels of racial segregation in the largest school districts are largely structured by existing residential segregation. Still, this study finds that the United States contains some attendance zones with highly irregular shapes—some of which are as irregular as the most irregular Congressional District. Although relatively rare, attendance zones that are highly irregular in shape almost always contain racially diverse student populations. This racial diversity contributes to racial integration within school districts. These findings contradict recent theoretical and empirical scholarship arguing that irregularly shaped zones contribute to racial segregation in schools. Our findings suggest that most racial segregation in school attendance zones is driven by large-scale segregation across residential areas rather than a widespread practice among school districts to exacerbate racial segregation by delineating irregularly shaped attendance zones. PMID:28804732

Life cycle assessment of segregating fattening pig urine and feces compared to conventional liquid manure management.

PubMed

De Vries, Jerke W; Aarnink, André J A; Groot Koerkamp, Peter W G; De Boer, Imke J M

2013-02-05

Gaseous emissions from in-house storage of liquid animal manure remain a major contributor to the environmental impact of manure management. Our aim was to assess the life cycle environmental consequences and reduction potential of segregating fattening pig urine and feces with an innovative V-belt system and to compare it to conventional liquid manure management, that is, the reference. Moreover, we aimed at analyzing the uncertainty of the outcomes related to applied emission factors. We compared a reference with two scenarios: segregation with solid, aerobically, stored feces and with liquid, anaerobically, stored feces. Results showed that, compared to the reference, segregation reduced climate change (CC) up to 82%, due to lower methane emission, reduced terrestrial acidification (TA) and particulate matter formation (PMF) up to 49%, through lower ammonia emission, but increased marine eutrophication up to 11% through nitrogen oxide emission from storage and nitrate leaching after field application. Fossil fuel depletion did not change. Segregation with liquid feces revealed lower environmental impact than segregation with solid feces. Uncertainty analysis supported the conclusion that segregating fattening pig urine and feces significantly reduced CC and additionally segregation with liquid feces significantly reduced TA and PMF compared to the reference.

Segregation in Post-Civil Rights America: Stalled Integration or End of the Segregated Century?

PubMed Central

Massey, Douglas S.; Rugh, Jacob S.

2016-01-01

In this paper we adjudicate between competing claims of persisting segregation and rapid integration by analyzing trends in residential dissimilarity and spatial isolation for African Americans, Hispanics, and Asians living in 287 consistently defined metropolitan areas from 1970 to 2010. On average, black segregation and isolation have fallen steadily but still remain very high in many areas, particularly those areas historically characterized by hypersegregation. In contrast, Hispanic segregation has increased slightly but Hispanic isolation has risen substantially owing to rapid population growth. Asian segregation has changed little and remains moderate, and although Asian isolation has increased it remains at low levels compared with other groups. Multivariate analyses reveal that segregation and isolation are being actively produced in some areas by restrictive density zoning regimes, large and/or rising minority percentages, lagging minority socioeconomic status, and active expressions of anti-black and anti-Latino sentiment, especially in large metropolitan areas. Areas displaying these characteristics are either integrating very slowly (in the case of blacks) or becoming more segregated (in the case of Hispanics), whereas those lacking these attributes are clearly moving toward integration, often quite rapidly. PMID:26966459

Morphology and luminosity segregation of galaxies in nearby loose groups

NASA Astrophysics Data System (ADS)

Girardi, M.; Rigoni, E.; Mardirossian, F.; Mezzetti, M.

2003-08-01

We study morphology and luminosity segregation of galaxies in loose groups. We analyze the two catalogs of groups identified in the Nearby Optical Galaxy (NOG) sample, by means of hierarchical and percolation ``friends-of-friends'' methods (HG and PG catalogs, respectively). In the first part of our analysis we consider 387 and 436 groups of HG and PG and compare morphology- (luminosity-) weighted to unweighted group properties: velocity dispersion, mean pairwise distance, and mean groupcentric distance of member galaxies. The second part of our analysis is based on two ensemble systems, one for each catalog, built by suitably combining together galaxies of all groups (1584 and 1882 galaxies for HG and PG groups). We find that earlier-type (brighter) galaxies are more clustered and lie closer to the group centers, both in position and in velocity, than later-type (fainter) galaxies. Spatial segregations are stronger than kinematical segregations. These effects are generally detected at the >˜ 3-sigma level. Luminosity segregation is shown to be independent of morphology segregation. Our main conclusions are strengthened by the detection of segregation in both hierarchical and percolation catalogs. Our results agree with a continuum of segregation properties of galaxies in systems, from low-mass groups to massive clusters.

Mapping of within-species segregation distortion in D. persimilis and hybrid sterility between D. persimilis and D. pseudoobscura

PubMed Central

McDermott, Shannon R.; Noor, Mohamed A. F.

2012-01-01

In contrast to the prevailing dogma in the 1990s, recent studies have suggested that an evolutionary history of segregation distortion within species may contribute to sterility in species hybrids. However, this recent work identified segregation distortion exclusively in species hybrids which may never have had an evolutionary history of segregation distortion in either parent species. We expand on previous work by using a strain of Drosophila persimilis exhibiting segregation distortion within species to generate QTL maps for segregation distortion and hybrid sterility in crosses between D. persimilis and D. pseudoobscura. The maps localize regions along the XR contributing to both phenotypes, and they indicate one region of overlap between the two maps. This overlap could provide preliminary evidence for an association between segregation distortion within species and hybrid sterility, but the localizations are currently too broad to have confidence in this conclusion. This work is a first step towards possibly supporting a genetic conflict model of speciation in this system. PMID:22966762

Transport analogy for segregation and granular rheology

NASA Astrophysics Data System (ADS)

Liu, Siying; McCarthy, Joseph J.

2017-08-01

Here, we show a direct connection between density-based segregation and granular rheology that can lead to insight into both problems. Our results exhibit a transition in the rate of segregation during simple shear that occurs at I ˜0.5 and mimics a coincident regime change in flow rheology. We propose scaling arguments that support a packing fraction criterion for this transition that can both explain our segregation results as well as unify existing literature studies of granular rheology. By recasting a segregation model in terms of rheological parameters, we establish an approach that not only collapses results for a wide range of conditions, but also yields a direct relationship between the coordination number z and the segregation velocity. Moreover, our approach predicts the precise location of the observed regime change or saturation. This suggests that it is possible to rationally design process operating conditions that lead to significantly lower segregation extents. These observations can have a profound impact on both the study of granular flow or mixing as well as industrial practice.

Adaptation of gastrointestinal nematode parasites to host genotype: single locus simulation models

PubMed Central

2013-01-01

Background Breeding livestock for improved resistance to disease is an increasingly important selection goal. However, the risk of pathogens adapting to livestock bred for improved disease resistance is difficult to quantify. Here, we explore the possibility of gastrointestinal worms adapting to sheep bred for low faecal worm egg count using computer simulation. Our model assumes sheep and worm genotypes interact at a single locus, such that the effect of an A allele in sheep is dependent on worm genotype, and the B allele in worms is favourable for parasitizing the A allele sheep but may increase mortality on pasture. We describe the requirements for adaptation and test if worm adaptation (1) is slowed by non-genetic features of worm infections and (2) can occur with little observable change in faecal worm egg count. Results Adaptation in worms was found to be primarily influenced by overall worm fitness, viz. the balance between the advantage of the B allele during the parasitic stage in sheep and its disadvantage on pasture. Genetic variation at the interacting locus in worms could be from de novo or segregating mutations, but de novo mutations are rare and segregating mutations are likely constrained to have (near) neutral effects on worm fitness. Most other aspects of the worm infection we modelled did not affect the outcomes. However, the host-controlled mechanism to reduce faecal worm egg count by lowering worm fecundity reduced the selection pressure on worms to adapt compared to other mechanisms, such as increasing worm mortality. Temporal changes in worm egg count were unreliable for detecting adaptation, despite the steady environment assumed in the simulations. Conclusions Adaptation of worms to sheep selected for low faecal worm egg count requires an allele segregating in worms that is favourable in animals with improved resistance but less favourable in other animals. Obtaining alleles with this specific property seems unlikely. With support from experimental data, we conclude that selection for low faecal worm egg count should be stable over a short time frame (e.g. 20 years). We are further exploring model outcomes with multiple loci and comparing outcomes to other control strategies. PMID:23714384

"Knife before wife": an exploratory study of gender and the UK medical profession.

PubMed

Miller, Karen; Clark, Donna

2008-01-01

The paper aims to explore the increasing feminisation of the medical profession and career progression of women in the medical profession. Furthermore, the paper explores the implications of gender segregation in the medical profession for health service provision. The paper presents an overview of studies in this area and draws upon primary, empirical research with medical practitioners and medical students. However, unlike most other studies the sample includes male and female participants. The research involved elite interviews and self-completion questionnaires in order to provide perspectives of both male and female medical practitioners and medical students. The findings are consistent with those of other studies; that gender discrimination and segregation is still prevalent in the medical profession. But there are significant differences in perceptions between the genders. Moreover, it is concluded that the gendered career structure and organisational culture of the health sector and medical profession create a role conflict between personal and professional lives. The current difficulties in reconciling this role conflict create barriers to the career progression of women in the medical profession. Further research in this area could include a longitudinal study of medical students and the impact of changes in the design of medical training and career structures to assess whether these changes enable female career progression in the medical profession. Further analysis is needed of gendered practices and career development in specific specialist areas, and the role of the medical profession, NHS and Royal Colleges should play in addressing gender and career progression in medicine. Gender segregation (vertical and horizontal) in the medical profession will have implications for the attraction, retention and increased shortages of practitioners in hospital and surgical specialities with the resultant economic and health provision inefficiencies. The paper provides a review of literature in this area, thereby providing a longitudinal perspective of gender and the medical profession. Moreover, the research sample includes both male and female medical practitioners and medical students, which provides perspectives from both genders and from those who have experience within the medical profession and from those beginning their career in the medical profession. The research will be of value to the medical profession, the NHS and Royal Colleges of Medicine.

Toward an International Lunar Polar Volatiles Strategy

NASA Technical Reports Server (NTRS)

Gruener, J. E.; Suzuki, N. H.; Carpenter, J. D.

2015-01-01

Fourteen international space agencies are participating in the International Space Exploration Coordination Group (ISECG), working together to advance a long-range human space exploration strategy. The ISECG is a voluntary, non-binding international coordination mechanism through which individual agencies may exchange information regarding interests, objectives, and plans in space exploration with the goal of strengthening both individual exploration programs as well as the collective effort. The ISECG has developed a Global Exploration Roadmap (GER) that reflects the coordinated international dialog and continued preparation for exploration beyond low-Earth orbit - beginning with the Moon and cis-lunar space, and continuing to near-Earth asteroids, and Mars. Space agencies agree that human space exploration will be most successful as an international endeavor, given the challenges of these missions. The roadmap demonstrates how initial capabilities can enable a variety of missions in the lunar vicinity, responding to individual and common goals and objectives, while contributing to building partnerships required for sustainable human space exploration that delivers value to the public.

Patterns of local segregation: Do they matter for neighborhood crime?

PubMed

Krivo, Lauren J; Byron, Reginald A; Calder, Catherine A; Peterson, Ruth D; Browning, Christopher R; Kwan, Mei-Po; Lee, Jae Yong

2015-11-01

In this paper, we extend recent research on the spatial measurement of segregation and the spatial dynamics of urban crime by conceptualizing, measuring, and describing local segregation by race-ethnicity and economic status, and examining the linkages of these conditions with levels of neighborhood violent and property crime. The analyses are based on all 8895 census tracts within a sample of 86 large U.S. cities. We fit multilevel models of crime that incorporate measures of local segregation. The results reveal that, net of city-level and neighborhood characteristics, White-Black local segregation is associated with lower violent and property crime. In contrast, local segregation of low income from high income households is connected with higher crime, particularly neighborhood violence. Copyright © 2015 Elsevier Inc. All rights reserved.

The Ndc80 internal loop is required for recruitment of the Ska complex to establish end-on microtubule attachment to kinetochores.

PubMed

Zhang, Gang; Kelstrup, Christian D; Hu, Xiao-Wen; Kaas Hansen, Mathilde J; Singleton, Martin R; Olsen, Jesper V; Nilsson, Jakob

2012-07-01

The Ndc80 complex establishes end-on attachment of kinetochores to microtubules, which is essential for chromosome segregation. The Ndc80 subunit is characterized by an N-terminal region that binds directly to microtubules, and a long coiled-coil region that interacts with Nuf2. A loop region in Ndc80 that generates a kink in the structure disrupts the long coiled-coil region but the exact function of this loop, has until now, not been clear. Here we show that this loop region is essential for end-on attachment of kinetochores to microtubules in human cells. Cells expressing loop mutants of Ndc80 are unable to align the chromosomes, and stable kinetochore fibers are absent. Through quantitative mass spectrometry and immunofluorescence we found that the binding of the spindle and kinetochore associated (Ska) complex depends on the loop region, explaining why end-on attachment is defective. This underscores the importance of the Ndc80 loop region in coordinating chromosome segregation through the recruitment of specific proteins to the kinetochore.

Is formation segregation melts in basaltic lava flows a viable analogue to melt generation in basaltic systems?

NASA Astrophysics Data System (ADS)

Thordarson, Thorvaldur; Sigmarsson, Olgeir; Hartley, Margaret E.; Miller, Jay

2010-05-01

Pahoehoe sheet lobes commonly exhibit a three-fold structural division into upper crust, core and lower crust, where the core corresponds to the liquid portion of an active lobe sealed by crust. Segregations are common in pahoehoe lavas and are confined to the core of individual lobes. Field relations and volume considerations indicate that segregation is initiated by generation of volatile-rich melt at or near the lower crust to core boundary via in-situ crystallization. Once buoyant, the segregated melt rises through the core during last stages of flow emplacement and accumulates at the base of the upper crust. The segregated melt is preserved as vesicular and aphyric, material within well-defined vesicle cylinders and horizontal vesicle sheets that make up 1-4% of the total lobe volume. We have undertaken a detailed sampling and chemical analysis of segregations and their host lava from three pahoehoe flow fields; two in Iceland and one in the Columbia River Basalt Group (CRBG). The Icelandic examples are: the olivine-tholeiite Thjorsa lava (24 cubic km) of the Bardarbunga-Veidivotn volcanic system and mildly alkalic Surtsey lavas (1.2 cubic km) of the Vestmannaeyjar volcanic system. The CRBG example is the tholeiitic ‘high-MgO group' Levering lava (>100? cubic km) of the N2 Grande Ronde Basalt. The thicknesses of the sampled lobes ranges from 2.3 to 14 m and each lobe feature well developed network of segregation structures [1,2,3]. Our whole-rock analyses show that the segregated melt is significantly more evolved than the host lava, with enrichment factors of 1.25 (Thjorsa) to 2.25 (Surtsey) for incompatible trace elements (Ba, Zr). Calculations indicate that the segregation melt was formed by 20 to 50% closed-system fractional crystallization of plagioclase (plus minor pyroxene and/or olivine). A more striking feature is the whole-rock composition of the segregations. In the olivine-tholeiite Thjorsa lava the segregations exhibit quartz tholeiite composition that is identical to the magma compositions produced by the nearby Grimsvotn and Kverkfjoll volcanic systems during the Holocene. The Surtsey segregations have whole-rock composition remarkably similar to the FeTi basalts from adjacent Katla volcanic system, whereas the segregations of the Levering flow are identical to the ‘low-MgO group' basalts of the CRBG. Is this a coincidence or does volatile induced liquid transfer, as inferred for the formation of the segregations, play an important role in magma differentiation in basaltic systems? [1]Thordarson & Self The Roza Member, Columbia River Basalt Group. J Geophys Res - Solid Earth [2] Sigmarsson, et al, 2009. Segregations in Surtsey lavas (Iceland). In Studies in Volcanology: The Legacy of George Walker. Special Publication of IAVCEI No 3. [3] Hartley & Thordarson, 2009, Melt segregations in a Columbia River Basalt lava flow. Lithos

Molecular and clinical studies of X-linked deafness among Pakistani families.

PubMed

Waryah, Ali M; Ahmed, Zubair M; Bhinder, Munir A; Binder, Munir A; Choo, Daniel I; Sisk, Robert A; Shahzad, Mohsin; Khan, Shaheen N; Friedman, Thomas B; Riazuddin, Sheikh; Riazuddin, Saima

2011-07-01

There are 68 sex-linked syndromes that include hearing loss as one feature and five sex-linked nonsyndromic deafness loci listed in the OMIM database. The possibility of additional such sex-linked loci was explored by ascertaining three unrelated Pakistani families (PKDF536, PKDF1132 and PKDF740) segregating X-linked recessive deafness. Sequence analysis of POU3F4 (DFN3) in affected members of families PKDF536 and PKDF1132 revealed two novel nonsense mutations, p.Q136X and p.W114X, respectively. Family PKDF740 is segregating congenital blindness, mild-to-profound progressive hearing loss that is characteristic of Norrie disease (MIM#310600). Sequence analysis of NDP among affected members of this family revealed a novel single nucleotide deletion c.49delG causing a frameshift and premature truncation (p.V17fsX1) of the encoded protein. These mutations were not found in 150 normal DNA samples. Identification of pathogenic alleles causing X-linked recessive deafness will improve molecular diagnosis, genetic counseling and molecular epidemiology of hearing loss among Pakistanis.

Patterns of ecology and distribution of the tree crickets Oecanthus dulcisonans and O. pellucens (Orthoptera: Gryllidae; Oecanthinae) in southern Italy.

PubMed

Labadessa, Rocco; Todisco, Simone

2016-09-21

Ecological proclivities of the tree cricket Oecanthus dulcisonans, which has been recently separated from the well known O. pellucens, have been poorly investigated. Moreover, studies on the patterns driving niche segregation between these related species are still needed. This study aims to explore the role of macro-habitat in shaping the distribution of O. dulcisonans and O. pellucens in southern Italy. Occurrence data were sampled by means of a rapid acoustic survey scheme at a regional scale. The significance of difference in ecological and habitat parameters was tested between the two species. While confirming species behavioural patterns, new findings are provided with regard to their ecological difference. Species distribution proves to be primarily driven by elevation gradient and temperature variation, with O. dulcisonans common and widespread in warmer lowlands and O. pellucens limited to higher altitudes. The two species also show significant spatial segregation within vegetation layers. These findings also provide cues for future studies on species interaction, as well as for the assessment of a monitoring scheme which may help interpreting the effects of broad environmental changes.

Spatial Segregation between Invasive and Native Commensal Rodents in an Urban Environment: A Case Study in Niamey, Niger

PubMed Central

Garba, Madougou; Dalecky, Ambroise; Kadaoure, Ibrahima; Kane, Mamadou; Hima, Karmadine; Veran, Sophie; Gagare, Sama; Gauthier, Philippe; Tatard, Caroline; Rossi, Jean-Pierre; Dobigny, Gauthier

2014-01-01

Invasive rodents have been responsible for the diffusion worldwide of many zoonotic agents, thus representing major threats for public health. Cities are important hubs for people and goods exchange and are thus expected to play a pivotal role in invasive commensal rodent dissemination. Yet, data about urban rodents' ecology, especially invasive vs. native species interactions, are dramatically scarce. Here, we provide results of an extensive survey of urban rodents conducted in Niamey, Niger, depicting the early stages of rodent bioinvasions within a city. We explore the species-specific spatial distributions throughout the city using contrasted approaches, namely field sampling, co-occurrence analysis, occupancy modelling and indicator geostatistics. We show that (i) two species (i.e. rural-like vs. truly commensal) assemblages can be identified, and that (ii) within commensal rodents, invasive (Rattus rattus and Mus musculus) and native (Mastomys natalensis) species are spatially segregated. Moreover, several pieces of arguments tend to suggest that these exclusive distributions reflect an ongoing native-to-invasive species turn over. The underlying processes as well as the possible consequences for humans are discussed. PMID:25379785

Race, foster care, and the politics of abandonment in New York City.

PubMed Central

Rosner, D; Markowitz, G

1997-01-01

Following the end of the Great Depression of the 1930s, the sectarian system of foster care services in New York City practiced open discrimination. African-American children were generally segregated in a small number of overcrowded and understaffed all-Black institutions. As the African-American migration to the city accelerated in the years following the outbreak of World War II, a small group of psychologists, jurists, philanthropists, and social workers began a systematic challenge to this system. This paper explores the role of racism in shaping New York's foster care system and the experience of African-American children who were forced to depend on services originally organized to serve Whites. It also looks at the ways race affected the way children were typed--as mentally ill, delinquent, or even criminal--in response to the structural realities of a system that sorted children into separate types of institutions according to race. The paper also provides the background for understanding the landmark challenge to segregation of children in sectarian and public institutions represented by Wilder v Sugarman. PMID:9366642

Tweeting From Left to Right: Is Online Political Communication More Than an Echo Chamber?

PubMed

Barberá, Pablo; Jost, John T; Nagler, Jonathan; Tucker, Joshua A; Bonneau, Richard

2015-10-01

We estimated ideological preferences of 3.8 million Twitter users and, using a data set of nearly 150 million tweets concerning 12 political and nonpolitical issues, explored whether online communication resembles an "echo chamber" (as a result of selective exposure and ideological segregation) or a "national conversation." We observed that information was exchanged primarily among individuals with similar ideological preferences in the case of political issues (e.g., 2012 presidential election, 2013 government shutdown) but not many other current events (e.g., 2013 Boston Marathon bombing, 2014 Super Bowl). Discussion of the Newtown shootings in 2012 reflected a dynamic process, beginning as a national conversation before transforming into a polarized exchange. With respect to both political and nonpolitical issues, liberals were more likely than conservatives to engage in cross-ideological dissemination; this is an important asymmetry with respect to the structure of communication that is consistent with psychological theory and research bearing on ideological differences in epistemic, existential, and relational motivation. Overall, we conclude that previous work may have overestimated the degree of ideological segregation in social-media usage. © The Author(s) 2015.

Molecular and Clinical Studies of X-linked Deafness Among Pakistani Families

PubMed Central

Waryah, Ali M.; Ahmed, Zubair M.; Choo, Daniel I.; Sisk, Robert A.; Binder, Munir A.; Shahzad, Mohsin; Khan, Shaheen N.; Friedman, Thomas B.; Riazuddin, Sheikh; Riazuddin, Saima

2011-01-01

There are 68 sex-linked syndromes that include hearing loss as one feature and five sex-linked nonsyndromic deafness loci listed in the OMIM database. The possibility of additional such sex-linked loci was explored by ascertaining three unrelated Pakistani families (PKDF536, PKDF1132, PKDF740) segregating X-linked recessive deafness. Sequence analysis of POU3F4 (DFN3) in affected members of families PKDF536 and PKDF1132 revealed two novel nonsense mutations, p.Q136X and p.W114X, respectively. Family PKDF740 is segregating congenital blindness, mild to profound progressive hearing loss that is characteristic of Norrie disease (MIM#310600). Sequence analysis of NDP among affected members of this family revealed a novel single nucleotide deletion c.49delG causing a frameshift and premature truncation (p.V17fsX1) of the encoded protein. These mutations were not found in 150 normal DNA samples. Identification of pathogenic alleles causing X-linked recessive deafness will improve molecular diagnosis, genetic counseling, and molecular epidemiology of hearing loss among Pakistanis. PMID:21633365

3-D Ultrastructure of O. tauri: Electron Cryotomography of an Entire Eukaryotic Cell

PubMed Central

Henderson, Gregory P.; Gan, Lu; Jensen, Grant J.

2007-01-01

The hallmark of eukaryotic cells is their segregation of key biological functions into discrete, membrane-bound organelles. Creating accurate models of their ultrastructural complexity has been difficult in part because of the limited resolution of light microscopy and the artifact-prone nature of conventional electron microscopy. Here we explored the potential of the emerging technology electron cryotomography to produce three-dimensional images of an entire eukaryotic cell in a near-native state. Ostreococcus tauri was chosen as the specimen because as a unicellular picoplankton with just one copy of each organelle, it is the smallest known eukaryote and was therefore likely to yield the highest resolution images. Whole cells were imaged at various stages of the cell cycle, yielding 3-D reconstructions of complete chloroplasts, mitochondria, endoplasmic reticula, Golgi bodies, peroxisomes, microtubules, and putative ribosome distributions in-situ. Surprisingly, the nucleus was seen to open long before mitosis, and while one microtubule (or two in some predivisional cells) was consistently present, no mitotic spindle was ever observed, prompting speculation that a single microtubule might be sufficient to segregate multiple chromosomes. PMID:17710148

43 CFR 2091.07 - Principles.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the Geothermal Steam Act, if so specified in the document that segregates the lands. The segregation... regulations or in the document that segregates the lands. Where there is an administrative appeal or review...

43 CFR 2091.07 - Principles.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the Geothermal Steam Act, if so specified in the document that segregates the lands. The segregation... regulations or in the document that segregates the lands. Where there is an administrative appeal or review...

43 CFR 2091.07 - Principles.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the Geothermal Steam Act, if so specified in the document that segregates the lands. The segregation... regulations or in the document that segregates the lands. Where there is an administrative appeal or review...

A STATEMENT OF CONCERN FOR PUBLIC EDUCATION IN PHILADELPHIA, WITH PARTICULAR REFERENCE TO THE SPECIAL NEEDS OF CHILDREN IN UNDERPRIVILEGED, SEGREGATED AREAS.

ERIC Educational Resources Information Center

Commission on Human Relations, Philadelphia, PA.

THIS 1960 STATEMENT OF THE COMMISSION ON HUMAN RELATIONS DESCRIBES THE PROBLEM OF DE FACTO SEGREGATION IN PHILADELPHIA. THE EXTENT OF SCHOOL AND FACULTY SEGREGATION IS INDICATED, AND THE REASONS FOR ITS EXISTENCE ARE DISCUSSED. IT IS FELT THAT THE CULTURAL DEFICIT WHICH RESULTS FROM RACIAL DISCRIMINATION AND SEGREGATION REQUIRES COMPENSATORY…

Black-White Residential Segregation: The Views of Myrdal in the 1940s and Trends of the 1980s.

ERIC Educational Resources Information Center

Farley, Reynolds

1994-01-01

Traces the development of black-white residential segregation in U.S. cities, and applies the views of Gunnar Myrdal, expressed in the 1940s, to housing trends in the 1980s. While such segregation has decreased, blacks remain more segregated than two other large minority groups (i.e., Hispanics and Asians). Forces influencing residential…

77 FR 12874 - Notice of Segregation of Public Lands in the State of Arizona Associated With the Proposed Mohave...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-02

...; AZA32315] Notice of Segregation of Public Lands in the State of Arizona Associated With the Proposed Mohave... material sales acts, for a period of 2 years. This segregation is being made in connection with the BLM's... County Wind Farm Project (Proposed Project). This segregation covers approximately 38,016.60 acres of BLM...

Segregation at the surfaces of CuxPd1-x alloys in the presence of adsorbed S

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, James B.; Priyadarshini, Deepika; Gellman, Andrew J.

2012-10-01

The influence of adsorbed S on surface segregation in Cu{sub x}Pd{sub 1 - x} alloys (S/Cu{sub x}Pd{sub 1 - x)} was characterized over a wide range of bulk alloy compositions (x = 0.05 to 0.95) using high-throughput Composition Spread Alloy Film (CSAF) sample libraries. Top-surface and near-surface compositions of the CSAFs were measured as functions of bulk Cu composition, x, and temperature using spatially resolved low energy ion scattering spectroscopy (LEISS) and X-ray photoemission spectroscopy (XPS). Preferential segregation of Cu to the top-surface of the S/Cu{sub x}Pd{sub 1 - x} CSAF was observed at all bulk compositions, x, but themore » extent of Cu segregation to the S/Cu{sub x}Pd{sub 1 - x} surface was lower than the Cu segregation to the surface of a clean Cu{sub x}Pd{sub 1 - x} CSAF, clear evidence of an S-induced “segregation reversal.” The Langmuir–McLean formulation of the Gibbs isotherm was used to estimate the enthalpy and entropy of Cu segregation to the top-surface, ΔH{sub seg}(x) and ΔS{sub seg}(x), at saturation sulfur coverages. While Cu segregation to the top-surface of the clean Cu{sub x}Pd{sub 1 - x} is exothermic (ΔH{sub seg} < 0) for all bulk Cu compositions, it is endothermic (ΔH{sub seg} > 0) for S/Cu{sub x}Pd{sub 1 - x}. Segregation to the S/Cu{sub x}Pd{sub 1 - x} surface is driven by entropy. Changes in segregation patterns that occur upon adsorption of S onto Cu{sub x}Pd{sub 1 - x} appear to be related to formation of energetically favored Pd{single bond}S bonds at the surface, which counterbalance the enthalpic driving forces for Cu segregation to the clean surface.« less