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Sample records for african approximate position

  1. Youth development: a positive strategy for African American youth.

    PubMed

    Rozie-Battle, Judith L

    2002-01-01

    The concept of positive youth development has been discussed and implemented for over ten years. The more recent emphasis on the connection between community and youth development is as important to the African American community in general as it is to African American youth. Opportunities to experience responsibility and involvement in their community, under the guidance of supportive adults, provide youth the chance of success for themselves and, ultimately, their communities. PMID:12413103

  2. APPROXIMATING SYMMETRIC POSITIVE SEMIDEFINITE TENSORS OF EVEN ORDER*

    PubMed Central

    BARMPOUTIS, ANGELOS; JEFFREY, HO; VEMURI, BABA C.

    2012-01-01

    Tensors of various orders can be used for modeling physical quantities such as strain and diffusion as well as curvature and other quantities of geometric origin. Depending on the physical properties of the modeled quantity, the estimated tensors are often required to satisfy the positivity constraint, which can be satisfied only with tensors of even order. Although the space P02m of 2mth-order symmetric positive semi-definite tensors is known to be a convex cone, enforcing positivity constraint directly on P02m is usually not straightforward computationally because there is no known analytic description of P02m for m > 1. In this paper, we propose a novel approach for enforcing the positivity constraint on even-order tensors by approximating the cone P02m for the cases 0 < m < 3, and presenting an explicit characterization of the approximation Σ2m ⊂ Ω2m for m ≥ 1, using the subset Ω2m⊂P02m of semi-definite tensors that can be written as a sum of squares of tensors of order m. Furthermore, we show that this approximation leads to a non-negative linear least-squares (NNLS) optimization problem with the complexity that equals the number of generators in Σ2m. Finally, we experimentally validate the proposed approach and we present an application for computing 2mth-order diffusion tensors from Diffusion Weighted Magnetic Resonance Images. PMID:23285313

  3. Positionality of African Americans and a Theoretical Accommodation of It: Rethinking Science Education Research

    ERIC Educational Resources Information Center

    Parsons, Eileen R. Carlton

    2008-01-01

    This essay addresses a call for research involving African Americans to interpret data from the historical, contemporary, and cultural experiences of African Americans. The essay argues for a science education research approach that explicitly considers the positionality of African Americans in the United States. This positionality involves the…

  4. Positive youth development among African American adolescents: examining single parents as a factor.

    PubMed

    Roberts, Shani R; Lewis, Rhonda K; Carmack, Chakema

    2011-01-01

    Over the past few decades researchers have begun to examine the importance of understanding positive youth development and the many contexts in which youth find themselves. The social contexts in which adolescent development occurs are varied and complex, particularly the development among African American youth. African American youth are faced with a number of challenges including living in single-parent homes, high teen pregnancy rates, and poor neighborhoods, yet many of these youth continue to thrive. The purpose of this study was to examine the relationship between family structure (single-parenting) and adolescent outcomes such as educational aspirations and sexual activity among African American adolescent youth aged 12-17. Approximately 462 African American youth were surveyed. A number of positive results emerged; for instance, there was a negative correlation between family structure and educational aspirations. The number of parents in the home did not interfere with youth wanting to complete high school and go on to college (r = - .218, r² = .04, p < .05). The results also showed that as educational aspirations increased, the number of sexual partners decreased (r = - .141, meaning that the more adolescents reported a desire to complete high school, they were less likely to report having sexual intercourse. These positive results should be promoted among African American youth so that those faced with these challenges will note that others have overcome and accomplished their goals. In this population educational aspirations were important. Limitations and future research are discussed. PMID:21992021

  5. Calculating Resonance Positions and Widths Using the Siegert Approximation Method

    ERIC Educational Resources Information Center

    Rapedius, Kevin

    2011-01-01

    Here, we present complex resonance states (or Siegert states) that describe the tunnelling decay of a trapped quantum particle from an intuitive point of view that naturally leads to the easily applicable Siegert approximation method. This can be used for analytical and numerical calculations of complex resonances of both the linear and nonlinear…

  6. Positive Individual and Social Behavior among Gang and Nongang African American Male Adolescents

    ERIC Educational Resources Information Center

    Taylor, Carl S.; Lerner, Richard M.; von Eye, Alexander; Bobek, Deborah L.; Balsano, Aida B.; Dowling, Elizabeth M.; Anderson, Pamela M.

    2003-01-01

    To explore potential bases of positive development among gang youth, attributes of positive individual and social behavior were assessed in individual interviews with 45 African American adolescent male members of inner-city Detroit gangs and 50 African American adolescent males from the same communities but involved in community-based…

  7. Optimizing care for African-American HIV-positive patients.

    PubMed

    Smith, Kimberly Y; Brutus, Andre; Cathcart, Ronald; Gathe, Joseph; Johnson, William; Jordan, Wilbert; Kwakwa, Helena A; Nkwanyou, Joseph; Page, Carlos; Scott, Robert; Vaughn, Anita C; Virgil, Luther A; Williamson, Diana

    2003-10-01

    The African-American community has been disproportionately affected HIV/AIDS, as noted by higher reported rates of HIV infection, higher proportion of AIDS cases, and more deaths caused by complications of AIDS than whites and other ethnic groups. In addition, epidemiologic trends suggest that African Americans with HIV infection are more often diagnosed later in the course of HIV disease than whites. Numerous reasons account for this disparity, including the lack of perception of risk and knowledge about HIV transmission as well as a delays in HIV testing and diagnosis in the African-American community. Understanding the important considerations in the management of HIV infection in the African-American patient may create awareness among health care professionals and broaden the knowledge of HIV-infected patients within the African-American community. PMID:14588093

  8. Signatures of positive selection in East African Shorthorn Zebu: a genome-wide SNP analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The small East African Shorthorn Zebu is the main indigenous cattle across East Africa. A recent genome wide SNPs analysis has revealed their ancient stable African taurine x Asian zebu admixture. Here, we assess the presence of candidate signature of positive selection in their genome, with the aim...

  9. Direction-preserving and Schur-monotonic Semi-separable Approximations of Symmetric Positive Definite Matrices

    SciTech Connect

    Gu, Ming; Li, Xiaoye Sherry; Vassilevski, Panayot S.

    2009-10-20

    For a given symmetric positive definite matrix A {element_of} R{sup nxn}, we develop a fast and backward stable algorithm to approximate A by a symmetric positive-definite semi-separable matrix, accurate to any prescribed tolerance. In addition, this algorithm preserves the product, AZ, for a given matrix Z {element_of} R{sup nxd}, where d << n. Our algorithm guarantees the positive-definiteness of the semi-separable matrix by embedding an approximation strategy inside a Cholesky factorization procedure to ensure that the Schur complements during the Cholesky factorization all remain positive definite after approximation. It uses a robust direction-preserving approximation scheme to ensure the preservation of AZ. We present numerical experiments and discuss potential implications of our work.

  10. Direction-Preserving and Schur-Monotonic Semi-Separable Approximations of Symmetric Positive Definite Matrices}

    SciTech Connect

    Gu, M; Li, X S; Vassilevski, P S

    2010-03-16

    For a given symmetric positive definite matrix A {element_of} R{sup N x N}, we develop a fast and backward stable algorithm to approximate A by a symmetric positive-definite semi-separable matrix, accurate to a constant multiple of any prescribed tolerance. In addition, this algorithm preserves the product, AZ, for a given matrix Z {element_of} R{sup N x d}, where d << N. Our algorithm guarantees the positive-definiteness of the semi-separable matrix by embedding an approximation strategy inside a Cholesky factorization procedure to ensure that the Schur complements during the Cholesky factorization all remain positive definite after approximation. It uses a robust direction-preserving approximation scheme to ensure the preservation of AZ. We present numerical experiments and discuss potential implications of our work.

  11. Are benefits conferred with greater socioeconomic position undermined by racial discrimination among African American men?

    PubMed Central

    Hudson, Darrell L.; Bullard, Kai M.; Neighbors, Harold W.; Geronimus, Arline T.; Yang, Juan; Jackson, James S.

    2012-01-01

    Background conventional wisdom suggests that increased socioeconomic resources should be related to better health. Considering the body of evidence demonstrating the significant association between racial discrimination and depression, we examined whether exposure to racial discrimination could attenuate the positive effects of increased levels of socioeconomic position (SEP) among African Americans. Specifically, this paper investigated the joint interactive effects of SEP and racial discrimination on the odds of depression among African Americans. Methods racial discrimination was measured using two measures, major and everyday discrimination. Study objectives were achieved using data from the National Survey of American Life, which included a nationally representative sample of African Americans (n =3570). Logistic regression models were used to estimate the effects of SEP and racial discrimination on the odds of depression. Results reports of racial discrimination were associated with increased risk of depression among American African men who possessed greater levels of education and income. Among African American men, significant, positive interactions were observed between education and experiences of major discrimination, which were associated with greater odds of depression (P = 0.02). Additionally, there were positive interactions between income and both measures of racial discrimination (income x everyday discrimination, P = 0.013; income x major discrimination, P = 0.02), which were associated with increased odds of depression (P = 0.02). Conclusions it is possible that experiences of racial discrimination could, in part, diminish the effects of increased SEP among African American men. PMID:22707995

  12. Negative and Positive Peer Influence: Relations to Positive and Negative Behaviors for African American, European American, and Hispanic Adolescents

    ERIC Educational Resources Information Center

    Padilla-Walker, Laura M.; Bean, Roy A.

    2009-01-01

    The purpose of the current study was to examine adolescents' perceptions of negative and positive peer influence (i.e., indirect peer association and direct peer pressure) as they related to adolescent behavior. Regression analyses were conducted using a sample of African American, European American, and Hispanic adolescents (N=1659, M age=16.06,…

  13. Sports Participation and Positive Correlates in African American, Latino, and White Girls

    ERIC Educational Resources Information Center

    Duncan, Susan C.; Strycker, Lisa A.; Chaumeton, Nigel R.

    2015-01-01

    The purpose of the study was to examine relations among sports participation and positive correlates across African American, Latino, and White girls. Positive correlate variables were self-perceptions (self-worth, body attractiveness, athletic competence), less depression, and participation in extracurricular activities. The sample comprised 372…

  14. Rational positive real approximations for LQG optimal compensators arising in active stabilization of flexible structures

    NASA Technical Reports Server (NTRS)

    Desantis, A.

    1994-01-01

    In this paper the approximation problem for a class of optimal compensators for flexible structures is considered. The particular case of a simply supported truss with an offset antenna is dealt with. The nonrational positive real optimal compensator transfer function is determined, and it is proposed that an approximation scheme based on a continued fraction expansion method be used. Comparison with the more popular modal expansion technique is performed in terms of stability margin and parameters sensitivity of the relative approximated closed loop transfer functions.

  15. The Afro-American Gospel Choir: Achieving a Positive Campus Climate for African American Students

    ERIC Educational Resources Information Center

    Pope, Myron L.; Moore, Cynthia

    2004-01-01

    For African American students, matriculation at a predominantly White institution of higher education can be quite intimidating. Religion is important in providing comfort and encouragement for many of these students. This article describes the Afro-American gospel choir at the University of Alabama and its role in providing a more positive campus…

  16. The Role of Faith in Adoption: Achieving Positive Adoption Outcomes for African American Children

    ERIC Educational Resources Information Center

    Belanger, Kathleen; Copeland, Sam; Cheung, Monit

    2008-01-01

    African American children are overrepresented in foster care by more than twice their proportion in the population (U.S. Government Accountability Office [USGAO], 2007). Building upon research relating faith (religiosity) to positive health and mental health, this study utilized cognitive and religious coping theories to examine the influence of…

  17. Career Ascension of African American Women in Executive Positions in Postsecondary Institutions

    ERIC Educational Resources Information Center

    Gamble, Erica D.

    2011-01-01

    Few studies exist regarding the factors and career paths that might be of value to African American females seeking an executive leadership position in a postsecondary institution. Using a qualitative phenomenological method, the essence of the experience of becoming a leader in postsecondary institutions was captured through face-to-face,…

  18. Unraveling the Source of African American Children's Positively Biased Perceptions of Peer Acceptance

    ERIC Educational Resources Information Center

    Dunkel, Stephanie B.; Kistner, Janet A.; David-Ferdon, Corinne

    2010-01-01

    The present study investigated possible ethnic contributions to overly positive self-perceptions in middle childhood. The goals of this study were threefold. First, the present study sought to replicate the intriguing findings reported by Zakriski and Coie that African American children overestimate their acceptance, and European American children…

  19. Weighing the Consequences: Self-Disclosure of HIV-Positive Status among African American Injection Drug Users

    ERIC Educational Resources Information Center

    Valle, Maribel; Levy, Judith

    2009-01-01

    Theorists posit that personal decisions to disclose being HIV positive are made based on the perceived consequences of that disclosure. This study examines the perceived costs and benefits of self-disclosure among African American injection drug users (IDUs). A total of 80 African American IDUs were interviewed in-depth subsequent to testing HIV…

  20. African signatures of recent positive selection in human FOXI1

    PubMed Central

    2010-01-01

    Background The human FOXI1 gene codes for a transcription factor involved in the physiology of the inner ear, testis, and kidney. Using three interspecies comparisons, it has been suggested that this may be a gene under human-specific selection. We sought to confirm this finding by using an extended set of orthologous sequences. Additionally, we explored for signals of natural selection within humans by sequencing the gene in 20 Europeans, 20 East Asians and 20 Yorubas and by analysing SNP variation in a 2 Mb region centered on FOXI1 in 39 worldwide human populations from the HGDP-CEPH diversity panel. Results The genome sequences recently available from other primate and non-primate species showed that FOXI1 divergence patterns are compatible with neutral evolution. Sequence-based neutrality tests were not significant in Europeans, East Asians or Yorubas. However, the Long Range Haplotype (LRH) test, as well as the iHS and XP-Rsb statistics revealed significantly extended tracks of homozygosity around FOXI1 in Africa, suggesting a recent episode of positive selection acting on this gene. A functionally relevant SNP, as well as several SNPs either on the putatively selected core haplotypes or with significant iHS or XP-Rsb values, displayed allele frequencies strongly correlated with the absolute geographical latitude of the populations sampled. Conclusions We present evidence for recent positive selection in the FOXI1 gene region in Africa. Climate might be related to this recent adaptive event in humans. Of the multiple functions of FOXI1, its role in kidney-mediated water-electrolyte homeostasis is the most obvious candidate for explaining a climate-related adaptation. PMID:20809947

  1. A Pilot Study to Engage and Counsel HIV-Positive African American Youth Via Telehealth Technology

    PubMed Central

    Yuan, Patrick; John, Malcolm; Sheon, Nicolas; Johnson, Mallory O.

    2013-01-01

    Abstract Antiretroviral nonadherence is a strong determinant of virologic failure and is negatively correlated with survival. HIV-positive African American youth have lower antiretroviral adherence and treatment engagement than other populations. We assessed the feasibility and acceptability of a telehealth (remote videoconferencing) medication counseling intervention as an innovative approach to address these disparities. HIV-positive African American youth (18–29 years old) on antiretrovirals were enrolled in a telehealth medication counseling session, followed by a semi-structured qualitative interview to explore likes/dislikes of the format, modality, and content; potential impact on adherence; privacy issues; and interaction quality. Fourteen participants with a mean age of 24 years, who were 86% male, and had a mean self-reported adherence in the past month of 89%, were interviewed. Participants stated that they liked telehealth, would use it if offered in clinic/research settings, and indicated that their privacy was maintained. Participants described telehealth as convenient and efficient, with positive impact on their knowledge. Telehealth provided a modality to interact with providers that participants described as less intimidating than in-person visits. Telehealth is feasible and acceptable for delivering medication counseling to HIV-positive African American youth when conducted in a controlled clinical setting and may improve quality of patient-provider dialogue. Use of telehealth may lead to more disclosure of treatment difficulties, increased patient comfort, and improved health education. PMID:23991691

  2. Source-position transformation: an approximate invariance in strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Schneider, Peter; Sluse, Dominique

    2014-04-01

    The main obstacle that gravitational lensing has in determining accurate masses of deflectors, or in determining precise estimates for the Hubble constant, is the degeneracy of lensing observables with respect to the mass-sheet transformation (MST). The MST is a global modification of the mass distribution which leaves all image positions, shapes, and flux ratios invariant, but which changes the time delay. Here we show that another global transformation of lensing mass distributions exists which leaves image positions and flux ratios almost invariant, and of which the MST is a special case. As is the case for the MST, this new transformation only applies if one considers only those source components that are at the same distance from us. Whereas for axi-symmetric lenses this source position transformation exactly reproduces all strong lensing observables, it does so only approximately for more general lens situations. We provide crude estimates for the accuracy with which the transformed mass distribution can reproduce the same image positions as the original lens model, and present an illustrative example of its performance. This new invariance transformation is most likely the reason why the same strong lensing information can be accounted for with rather different mass models.

  3. Increasing Antiretroviral Adherence for HIV-Positive African Americans (Project Rise): A Treatment Education Intervention Protocol

    PubMed Central

    Bogart, Laura M; Mutchler, Matt G; McDavitt, Bryce; Mutepfa, Kieta D; Risley, Brian

    2016-01-01

    Background HIV-positive African Americans have been shown to have lower adherence to antiretroviral therapy (ART) than those of other races/ethnicities, yet adherence interventions have rarely been tailored to the needs of this population. Objective We developed and will evaluate a treatment education adherence intervention (called Rise) that was culturally adapted to address the needs of African Americans living with HIV. Methods This randomized controlled trial will examine the effects of the Rise intervention on ART adherence and HIV viral load. African Americans on ART who report adherence problems will be recruited from the community and randomly assigned to receive the intervention or usual care for 6 months. The intervention consists of 6-10 individual counseling sessions, with more sessions provided to those who demonstrate lower adherence. Primary outcomes include adherence as monitored continuously with Medication Event Monitoring Systems (MEMS) caps, and viral load data received from the participant’s medical provider. Survey assessments will be administered at baseline and month 6. Results The trial is ongoing. Conclusions If effective, the Rise intervention will provide community-based organizations with an intervention tailored to address the needs of African Americans for promoting optimal ART adherence and HIV clinical outcomes. Trial Registration Clinicaltrials.gov NCT01350544; https://clinicaltrials.gov/ct2/show/NCT01350544 (Archived by WebCite at http://www.webcitation.org/6fjqqnmn0). PMID:27025399

  4. Approximate reversibility in the context of entropy gain, information gain, and complete positivity

    NASA Astrophysics Data System (ADS)

    Buscemi, Francesco; Das, Siddhartha; Wilde, Mark M.

    2016-06-01

    There are several inequalities in physics which limit how well we can process physical systems to achieve some intended goal, including the second law of thermodynamics, entropy bounds in quantum information theory, and the uncertainty principle of quantum mechanics. Recent results provide physically meaningful enhancements of these limiting statements, determining how well one can attempt to reverse an irreversible process. In this paper, we apply and extend these results to give strong enhancements to several entropy inequalities, having to do with entropy gain, information gain, entropic disturbance, and complete positivity of open quantum systems dynamics. Our first result is a remainder term for the entropy gain of a quantum channel. This result implies that a small increase in entropy under the action of a subunital channel is a witness to the fact that the channel's adjoint can be used as a recovery map to undo the action of the original channel. We apply this result to pure-loss, quantum-limited amplifier, and phase-insensitive quantum Gaussian channels, showing how a quantum-limited amplifier can serve as a recovery from a pure-loss channel and vice versa. Our second result regards the information gain of a quantum measurement, both without and with quantum side information. We find here that a small information gain implies that it is possible to undo the action of the original measurement if it is efficient. The result also has operational ramifications for the information-theoretic tasks known as measurement compression without and with quantum side information. Our third result shows that the loss of Holevo information caused by the action of a noisy channel on an input ensemble of quantum states is small if and only if the noise can be approximately corrected on average. We finally establish that the reduced dynamics of a system-environment interaction are approximately completely positive and trace preserving if and only if the data processing

  5. Workforce Diversity in Higher Education: Career Support Factors Influencing Ascendancy of African American Women to Senior-Level Positions

    ERIC Educational Resources Information Center

    Blackstone, Tondelaya K.

    2011-01-01

    The focus of this study was how knowledge of the barriers to advancement for African American women (AAW) and key career support factors (KCSFs) influence the career advancement of African American women (AAW) to senior-level positions in higher education. The research method for this study consisted of the triangulation of evidence from multiple…

  6. Approximate Joint Diagonalization and Geometric Mean of Symmetric Positive Definite Matrices

    PubMed Central

    Congedo, Marco; Afsari, Bijan; Barachant, Alexandre; Moakher, Maher

    2015-01-01

    We explore the connection between two problems that have arisen independently in the signal processing and related fields: the estimation of the geometric mean of a set of symmetric positive definite (SPD) matrices and their approximate joint diagonalization (AJD). Today there is a considerable interest in estimating the geometric mean of a SPD matrix set in the manifold of SPD matrices endowed with the Fisher information metric. The resulting mean has several important invariance properties and has proven very useful in diverse engineering applications such as biomedical and image data processing. While for two SPD matrices the mean has an algebraic closed form solution, for a set of more than two SPD matrices it can only be estimated by iterative algorithms. However, none of the existing iterative algorithms feature at the same time fast convergence, low computational complexity per iteration and guarantee of convergence. For this reason, recently other definitions of geometric mean based on symmetric divergence measures, such as the Bhattacharyya divergence, have been considered. The resulting means, although possibly useful in practice, do not satisfy all desirable invariance properties. In this paper we consider geometric means of covariance matrices estimated on high-dimensional time-series, assuming that the data is generated according to an instantaneous mixing model, which is very common in signal processing. We show that in these circumstances we can approximate the Fisher information geometric mean by employing an efficient AJD algorithm. Our approximation is in general much closer to the Fisher information geometric mean as compared to its competitors and verifies many invariance properties. Furthermore, convergence is guaranteed, the computational complexity is low and the convergence rate is quadratic. The accuracy of this new geometric mean approximation is demonstrated by means of simulations. PMID:25919667

  7. Negative and positive peer influence: Relations to positive and negative behaviors for African American, European American, and Hispanic adolescents.

    PubMed

    Padilla-Walker, Laura M; Bean, Roy A

    2009-04-01

    The purpose of the current study was to examine adolescents' perceptions of negative and positive peer influence (i.e., indirect peer association and direct peer pressure) as they related to adolescent behavior. Regression analyses were conducted using a sample of African American, European American, and Hispanic adolescents (N=1659, M age=16.06, SD=1.10). The study found differences and similarities in relation to respondents' ethnicity vis-à-vis indirect peer association and adolescent behavior. Although few ethnic-based differences occurred as a function of indirect negative peer association, indirect positive peer association was not as consistently or as strongly related to behaviors for minority youth as it was for European American youth. PMID:18703225

  8. Successive approximation algorithm for beam-position-monitor-based LHC collimator alignment

    NASA Astrophysics Data System (ADS)

    Valentino, Gianluca; Nosych, Andriy A.; Bruce, Roderik; Gasior, Marek; Mirarchi, Daniele; Redaelli, Stefano; Salvachua, Belen; Wollmann, Daniel

    2014-02-01

    Collimators with embedded beam position monitor (BPM) button electrodes will be installed in the Large Hadron Collider (LHC) during the current long shutdown period. For the subsequent operation, BPMs will allow the collimator jaws to be kept centered around the beam orbit. In this manner, a better beam cleaning efficiency and machine protection can be provided at unprecedented higher beam energies and intensities. A collimator alignment algorithm is proposed to center the jaws automatically around the beam. The algorithm is based on successive approximation and takes into account a correction of the nonlinear BPM sensitivity to beam displacement and an asymmetry of the electronic channels processing the BPM electrode signals. A software implementation was tested with a prototype collimator in the Super Proton Synchrotron. This paper presents results of the tests along with some considerations for eventual operation in the LHC.

  9. Understanding the Effects of Multiple Stigmas Among Formerly Incarcerated HIV-Positive African American Men.

    PubMed

    Brinkley-Rubinstein, Lauren

    2015-04-01

    Race, HIV, and incarceration, as individual and intersecting markers of social identity, have associated stigma. While some research has indicated multiple burdens of stigma can be additive, there remains a lack of investigation relative to the effects of stigma among minorities who experience both HIV and incarceration. Therefore, the current study examines the impact of multiple forms of stigma via a series of ethnographic interviews (n = 46) conducted with 12 African American men over a one-year period. Results suggest that intersecting forms of stigma can have a severe impact on the general health, mental health, and the reintegration process of formerly incarcerated HIV-positive men. Additionally, participants often conceptualized all forms of stigma separately, which resulted in compounded burden of navigation. The experience of multiple forms of stigma was also often internalized as self-stigma whereby HIV-positive individuals with a history of incarceration assumed dominant norms related to both HIV and incarceration. PMID:25915701

  10. A study of HIV positive undocumented African migrants' access to health services in the UK.

    PubMed

    Whyte, James; Whyte, Maria D; Hires, Kimberly

    2015-01-01

    Newly immigrated persons, whatever their origin, tend to fall in the lower socioeconomic levels. In fact, failure of an asylum application renders one destitute in a large proportion of cases, often resulting in a profound lack of access to basic necessities. With over a third of HIV positive failed asylum seekers reporting no income, and the remainder reporting highly limited resources, poverty is a reality for the vast majority. The purpose of the study was to determine the basic social processes that guide HIV positive undocumented migrant's efforts to gain health services in the UK. The study used the Grounded Theory Approach. Theoretical saturation occurred after 16 participants were included in the study. The data included reflections of the prominent factors related to the establishment of a safe and productive life and the ability of individuals to remain within the UK. The data reflected heavily upon the ability of migrants to enter the medical care system during their asylum period, and on an emerging pattern of service denial after loss on immigration appeal. The findings of this study are notable in that they have demonstrated sequence of events along a timeline related to the interaction between the asylum process and access to health-related services. The results reflect that African migrants maintain a degree of formal access to health services during the period that they possess legal access to services and informal access after the failure of their asylum claim. The purpose of this paper is to examine the basic social processes that characterize efforts to gain access to health services among HIV positive undocumented African migrants to the UK. The most recent estimates indicate that there are a total of 618,000 migrants who lack legal status within the UK. Other studies have placed the number of undocumented migrants within the UK in the range of 525,000-950,000. More than 442,000 are thought to dwell in the London metropolitan area. Even in

  11. Promoting positive youth development by examining the career and educational aspirations of African American males: implications for designing educational programs.

    PubMed

    Lee, Felecia A; Lewis, Rhonda K; Sly, Jamilia R; Carmack, Chakema; Roberts, Shani R; Basore, Polly

    2011-01-01

    African American males experience poor academic performance, high absenteeism at school, and are at increased risk of being involved in violence than other racial groups. Given that the educational outlook for African American males appears bleak, it is important to assess the aspirations of these adolescent males in order to find the gap between aspirations and educational attainment. In order to promote positive development within this population, it is essential that factors that affect African American males be identified. A survey was administered to male students attending elementary, middle, and high schools in a local school district. A cross-sectional study was conducted to examine the career and educational aspirations of African American males. A total of 473 males were surveyed: 45% African American, 22% Caucasian, 13% biracial, and 19% Other (including Asian American, Hispanic, Native American). The results revealed that African American males aspired to attend college at the same rate as other ethnic groups. Also, African American males were more likely to aspire to be professional athletes than males from other ethnic groups. Important factors to consider when designing a program are discussed as well as future research and limitations. PMID:21992020

  12. A fast, always positive definite and normalizable approximation of non-Gaussian likelihoods

    NASA Astrophysics Data System (ADS)

    Sellentin, Elena

    2015-10-01

    In this paper we extend the previously published DALI-approximation for likelihoods to cases in which the parameter dependence is in the covariance matrix. The approximation recovers non-Gaussian likelihoods, and reduces to the Fisher matrix approach in the case of Gaussianity. It works with the minimal assumptions of having Gaussian errors on the data, and a covariance matrix that possesses a converging Taylor approximation. The resulting approximation works in cases of severe parameter degeneracies and in cases where the Fisher matrix is singular. It is at least 1000 times faster than a typical Monte Carlo Markov Chain run over the same parameter space. Two example applications, to cases of extremely non-Gaussian likelihoods, are presented - one demonstrates how the method succeeds in reconstructing completely a ring-shaped likelihood. A public code is released here: http://lnasellentin.github.io/DALI/.

  13. Weighing the consequences: self-disclosure of HIV-positive status among African American injection drug users.

    PubMed

    Valle, Maribel; Levy, Judith

    2009-02-01

    Theorists posit that personal decisions to disclose being HIV positive are made based on the perceived consequences of that disclosure. This study examines the perceived costs and benefits of self-disclosure among African American injection drug users (IDUs). A total of 80 African American IDUs were interviewed in-depth subsequent to testing HIV positive. Participants reported that interpersonal costs of self-disclosure included stigma, loss of sexual/romantic partners, emotional harming of family/friends, shattering of privacy, physical isolation, blame, and loss of income. The benefits of disclosure included social support, emotional catharsis, and income. Four factors that help to tip the scales in either direction were identified. Study findings have implications for the delivery of counseling, testing, and partner notification services to African American IDUs living with HIV. PMID:18697884

  14. Evidence of Positive Selection in Mitochondrial Complexes I and V of the African Elephant

    PubMed Central

    Finch, Tabitha M.; Zhao, Nan; Korkin, Dmitry; Frederick, Katy H.; Eggert, Lori S.

    2014-01-01

    As species evolve, they become adapted to their local environments. Detecting the genetic signature of selection and connecting that to the phenotype of the organism, however, is challenging. Here we report using an integrative approach that combines DNA sequencing with structural biology analyses to assess the effect of selection on residues in the mitochondrial DNA of the two species of African elephants. We detected evidence of positive selection acting on residues in complexes I and V, and we used homology protein structure modeling to assess the effect of the biochemical properties of the selected residues on the enzyme structure. Given the role these enzymes play in oxidative phosphorylation, we propose that the selected residues may contribute to the metabolic adaptation of forest and savanna elephants to their unique habitats. PMID:24695069

  15. Stigma and Sexual Health Risk in HIV-Positive African American Young Men Who Have Sex with Men

    PubMed Central

    Doty, Nathan; Hawkins, Linda A.; Gaskins, Clare S.; Beidas, Rinad; Rudy, Bret J.

    2010-01-01

    Abstract Understanding the multiple forms of stigma experienced by young HIV-positive African American men who have sex with men and how they relate to sexual risk behaviors is essential to design effective HIV prevention programs. This study of 40 African American young MSM found that 90% of those surveyed experienced sexual minority stigma, 88% experienced HIV stigma, and 78% experienced dual stigma. Sexual minority stigma was characterized by experiences of social avoidance, and HIV stigma, by shame. Individuals with high HIV stigma were significantly more likely to engage in unprotected sex while high or intoxicated. Associations between stigma and sexual practices were examined; youth endorsing higher levels of sexual minority stigma engaged in less insertive anal intercourse. Individuals endorsing more HIV stigma reported more receptive anal intercourse. These findings support the development of stigma-informed secondary prevention interventions for African American HIV-positive young MSM. PMID:20673080

  16. "I Don't Know Who to Blame": HIV-Positive South African Women Navigating Heterosexual Infection

    ERIC Educational Resources Information Center

    Long, Carol

    2009-01-01

    Women who become HIV infected through heterosexual transmission are faced with the task of making sense of how they became infected. This paper presents a qualitative analysis based on interviews with 35 HIV-positive South African Black women. A specific theme, that blame of a male partner was avoided or disavowed in interviews, is explored in…

  17. Barriers and Bridges to Positive Cross-Ethnic Relations: African American and White Parent Socialization Beliefs and Practices.

    ERIC Educational Resources Information Center

    Hamm, Jill V.

    2001-01-01

    Using interviews and focus groups, lower and middle socioeconomic status (SES) African American parents and middle SES white parents discussed their objectives regarding cross-ethnic relations and how they helped their children forge positive cross-ethnic relations. The groups relied on different methods to promote socialization. Parents' efforts…

  18. Health impact of incarceration on HIV-positive African American males: a qualitative exploration.

    PubMed

    Brinkley-Rubinstein, Lauren; Turner, William L

    2013-08-01

    Previous research suggests that incarceration can have a negative effect on health. These health effects have an especially profound impact on HIV-positive individuals. As such, the current study investigates how incarceration affects the health of 12 African American HIV-positive formerly incarcerated males recruited via an AIDS Service Organization. Individuals were enrolled via purposive sampling and engaged in a series of in-depth interviews over a yearlong period (n=46). Participants ranged in age from 33 to 61 years. Most had finished high school, were not employed at time of first and last interview, and most were primarily residing at a homeless shelter. The time incarcerated ranged among participants from 3 months to 3 years. Findings suggest that health is impacted via limited and delayed access to medication, stigma, and poor quality of medical care while incarcerated. Health continues to worsen after release, largely due to incarceration's impact on individuals' social context. Macro-level policy limits opportunity to fulfill basic needs such as housing and hinders one's ability to be gainfully employed. Moreover, stigma, loss of social support, and a delay in accessing HIV-related services deleteriously impacts individuals' mental and physical health status. Implications for practice, policy and future research are also discussed. PMID:23968205

  19. The impact of structured support groups for pregnant South African women recently diagnosed HIV positive.

    PubMed

    Mundell, Jonathan P; Visser, Maretha J; Makin, Jennifer D; Kershaw, Trace S; Forsyth, Brian W C; Jeffery, Bridget; Sikkema, Kathleen J

    2011-08-31

    The authors of this study evaluated a structured 10-session psychosocial support group intervention for newly HIV-diagnosed pregnant South African women. Participants were expected to display increases in HIV disclosure, self-esteem, active coping and positive social support, and decreases in depression, avoidant coping, and negative social support. Three hundred sixty-one pregnant HIV-infected women were recruited from four antenatal clinics in Tshwane townships from April 2005 to September 2006. Using a quasi-experimental design, assessments were conducted at baseline and two and eight months post-intervention. A series of random effects regression analyses were conducted, with the three assessment points treated as a random effect of time. At both follow-ups, the rate of disclosure in the intervention group was significantly higher than that of the comparison group (p<0.001). Compared to the comparison group at the first follow-up, the intervention group displayed higher levels of active coping (t=2.68, p<0.05) and lower levels of avoidant coping (t=-2.02, p<0.05), and those who attended at least half of the intervention sessions exhibited improved self-esteem (t=2.11, p<0.05). Group interventions tailored for newly HIV positive pregnant women, implemented in resource-limited settings, may accelerate the process of adjusting to one's HIV status, but may not have sustainable benefits over time. PMID:21973110

  20. The Impact of Structured Support Groups for Pregnant South African Women Recently Diagnosed HIV Positive

    PubMed Central

    Mundell, Jonathan P.; Visser, Maretha J.; Makin, Jennifer D.; Kershaw, Trace S.; Forsyth, Brian W. C.; Jeffery, Bridget; Sikkema, Kathleen J.

    2014-01-01

    The authors of this study evaluated a structured 10-session psychosocial support group intervention for newly HIV-diagnosed pregnant South African women. Participants were expected to display increases in HIV disclosure, self-esteem, active coping and positive social support, and decreases in depression, avoidant coping, and negative social support. Three hundred sixty-one pregnant HIV-infected women were recruited from four antenatal clinics in Tshwane townships from April 2005 to September 2006. Using a quasi-experimental design, assessments were conducted at baseline and two and eight months post-intervention. A series of random effects regression analyses were conducted, with the three assessment points treated as a random effect of time. At both follow-ups, the rate of disclosure in the intervention group was significantly higher than that of the comparison group (p < 0.001). Compared to the comparison group at the first follow-up, the intervention group displayed higher levels of active coping (t = 2.68, p < 0.05) and lower levels of avoidant coping (t = −2.02, p < 0.05), and those who attended at least half of the intervention sessions exhibited improved self-esteem (t = 2.11, p < 0.05). Group interventions tailored for newly HIV positive pregnant women, implemented in resource-limited settings, may accelerate the process of adjusting to one's HIV status, but may not have sustainable benefits over time. PMID:21973110

  1. African-American Cancer Survivors' Use of Religious Beliefs to Positively Influence the Utilization of Cancer Care.

    PubMed

    Hamilton, Jill B; Galbraith, Kayoll V; Best, Nakia C; Worthy, Valarie C; Moore, L T C Angelo D

    2015-10-01

    Among African-Americans, religion impacts health-seeking behaviors. This qualitative study used criterion purposeful sampling and thematic analysis in analysis of data from 31 African-American cancer patients to understand the influence of religion on the utilization of cancer care services. Our findings suggest that religious beliefs and practices positively influenced attitudes toward their illness and ability to endure treatment. God's ability to heal and cure, God's control over survival, God's will over their lives, and God's promise for health and prosperity were examples of survivor's religious beliefs. Religious practices such as prayer promoted a trusting relationship with healthcare providers and were a source of strength and encouragement. PMID:25269756

  2. Verification of the Astronomical Almanac's algorithm for approximate the position of the sun

    NASA Astrophysics Data System (ADS)

    Zheng, Lin; Shen, Guotu; Cai, Jiguang; Dong, Zhanhai; Gao, Jing

    2013-09-01

    With the consumption of the resources, it's important to develop clean solar energy that can solve the problem of energy shortage. Obtaining an accurate position of the sun is the premise of using the solar energy efficiently. An accurate solar position includes two factors that are elevation and azimuth. In the paper, Joseph J. Michalsky's algorithm for calculation of the solar position is verified that is taken from the American Astronomical Almanac. The algorithm has been written into program by Joseph J. Michalsky in FORTRAN. In the paper, it's has been adapted to visual C++ that can calculate the solar elevation and azimuth and errors or some places that less accurate are corrected. The Chinese Astronomical Almanac for the year 1985 doesn't tabulate elevation and azimuth. The quantities needed to calculate elevation and azimuth are the right ascension, the declination and the Greenwich mean sidereal time that are tabulated in the Almanac. Comparing those variables that calculated from the algorithm with the data from the Chinese Astronomical Almanac for the year 1985, it can be found that the biggest difference of the two ways is only 0.01°, 0.01° and 0.0001h respectively, which prove the accuracy of the algorithm indirectly. The measured data that only include elevation comes from Basic Data of Geography in China written by Institute of Geography, Chinese Academy of Sciences. Comparing elevation given by the algorithm with the measured data, it shows that the algorithm can be accurate calculating the position of the sun in some extent. And the paper shows in detail the conversion from the local real solar time to Universal Time because the time in Basic Data of Geography in China is the local real solar time. Finally we notice that the 0.01° accuracy mentioned by other paper is not the accuracy of the elevation and azimuth of the sun, but the accuracy of the right ascension and declination. It's easy to understand why the difference of the results

  3. Genome-wide identification of signatures of positive selection in African admixed zebu cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The introduction of humped zebu to the African continent has led to genetic introgression with the local African humpless taurine. A mosaic of zebu x taurine cattle populations adapted to the local environments (e.g., semi-dry desert, humid and sub-humid forested areas) has arisen as a result of thi...

  4. Brown oculocutaneous albinism is allelic to tyrosinase-positive oculocutaneous albinism in southern African Negroids

    SciTech Connect

    Manga, P.; Ramsay, M.; Kromberg, J.; Jenkins, T.

    1994-09-01

    Brown oculocutaneous albinism (BOCA) is an autosomal recessive disorder involving a decrease in pigment of the skin, hair and eyes as well as decreased visual acuity. Evidence from two families who have co-existent BOCA and tyrosinase-positive oculocutaneous albinism (ty-pos OCA), suggests that the two conditions are allelic. Ty-pos OCA has been mapped to chromosome 15q11-q12 and the gene has been confirmed to be the human homologue (P) of the mouse pink-eyed dilute gene (p). Seven markers known to be linked to the P gene, D15S11, D15S10, MS14, GABA3, GABA5, IR10 and pCMW-1, were used to construct haplotypes in 5 families with BOCA. The haplotype data was subjected to linkage analysis and a maximum lod score of 2.85 ({theta} 0.0) was obtained. It has been reported previously that BOCA, in an Afro-American, was due to the lack of tyrosinase-protein 1 (Trp-1) in melanocytes. Trp-1 has been excluded as the disease-causing locus in the southern African families by linkage analysis with D9S43. A lod score of -2.02 was obtained at {theta} = 0.02.

  5. Mutations Associated With Occult Hepatitis B in HIV-Positive South Africans

    PubMed Central

    Powell, Eleanor A.; Gededzha, Maemu P.; Rentz, Michael; Rakgole, Nare J.; Selabe, Selokela G.; Seleise, Tebogo A.; Mphahlele, M. Jeffrey; Blackard, Jason T.

    2015-01-01

    Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations—those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references—were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro. PMID:25164924

  6. Positive immunolabelling for feline infectious peritonitis in an African lion (Panthera leo) with bilateral panuveitis.

    PubMed

    Mwase, M; Shimada, K; Mumba, C; Yabe, J; Squarre, D; Madarame, H

    2015-01-01

    A 15-year-old male African lion (Panthera leo) was presented with blindness due to bilateral panuveitis with retinal detachment. Feline coronavirus (FCoV) antigen was identified immunohistochemically in ocular macrophages, consistent with a diagnosis of feline infectious peritonitis (FIP) infection. This is the first report of FIP in an African lion and the first report of ocular FIP in a non-domestic felid. PMID:25678422

  7. The associations between resilience, social capital and self-rated health among HIV-positive South Africans.

    PubMed

    Dageid, Wenche; Grønlie, Anette A

    2015-11-01

    This study examined the relationship between resilience, social capital and self-rated health among 263 HIV-positive South Africans living in poverty, using questionnaires. Self-rated good health was predicted by younger age, trust in community-based organizations and having contacts of different religions. The findings highlight the importance of community-based networks and resources for care and support for persons living with HIV/AIDS in poor, rural areas. Furthermore, resilience, which also related positively to education and income, contributed positively to self-rated health, drawing attention to the interplay between resources at individual and community levels. PMID:24345683

  8. Functional analysis of 'a' determinant mutations associated with occult HBV in HIV-positive South Africans.

    PubMed

    Powell, Eleanor A; Boyce, Ceejay L; Gededzha, Maemu P; Selabe, Selokela G; Mphahlele, M Jeffrey; Blackard, Jason T

    2016-07-01

    Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in the absence of hepatitis B surface antigen (HBsAg). Occult HBV is associated with the development of hepatocellular carcinoma, reactivation during immune suppression, and virus transmission. Viral mutations contribute significantly to the occult HBV phenotype. Mutations in the 'a' determinant of HBsAg are of particular interest, as these mutations are associated with immune escape, vaccine escape and diagnostic failure. We examined the effects of selected occult HBV-associated mutations identified in a population of HIV-positive South Africans on HBsAg production in vitro. Mutations were inserted into two different chronic HBV backbones and transfected into a hepatocyte-derived cell line. HBsAg levels were quantified by enzyme-linked immunosorbent assay (ELISA), while the detectability of mutant HBsAg was determined using an HA-tagged HBsAg expression system. Of the seven mutations analysed, four (S132P, C138Y, N146D and C147Y) resulted in decreased HBsAg expression in one viral background but not in the second viral background. One mutation (N146D) led to a decrease in HBsAg detected as compared to HA-tag, indicating that this mutation compromises the ability of the ELISA to detect HBsAg. The contribution of occult-associated mutations to the HBsAg-negative phenotype of occult HBV cannot be determined adequately by testing the effect of the mutation in a single viral background, and rigorous analysis of these mutations is required. PMID:27031988

  9. Exchange energy gradients with respect to atomic positions and cell parameters within the Hartree-Fock Gamma-point approximation.

    PubMed

    Weber, Valéry; Daul, Claude; Challacombe, Matt

    2006-06-01

    Recently, linear scaling construction of the periodic exact Hartree-Fock exchange matrix within the Gamma-point approximation has been introduced [J. Chem. Phys. 122, 124105 (2005)]. In this article, a formalism for evaluation of analytical Hartree-Fock exchange energy gradients with respect to atomic positions and cell parameters at the Gamma-point approximation is presented. While the evaluation of exchange gradients with respect to atomic positions is similar to those in the gas phase limit, the gradients with respect to cell parameters involve the accumulation of atomic gradients multiplied by appropriate factors and a modified electron repulsion integral (ERI). This latter integral arises from use of the minimum image convention in the definition of the Gamma-point Hartree-Fock approximation. We demonstrate how this new ERI can be computed with the help of a modified vertical recurrence relation in the frame of the Obara-Saika and Head-Gordon-Pople algorithm. As an illustration, the analytical gradients have been used in conjunction with the QUICCA algorithm [K. Nemeth and M. Challacombe, J. Chem. Phys. 121, 2877 (2004)] to optimize periodic systems at the Hartree-Fock level of theory. PMID:16774396

  10. Exchange energy gradients with respect to atomic positions and cell parameters within the Hartree-Fock Γ-point approximation

    NASA Astrophysics Data System (ADS)

    Weber, Valéry; Daul, Claude; Challacombe, Matt

    2006-06-01

    Recently, linear scaling construction of the periodic exact Hartree-Fock exchange matrix within the Γ-point approximation has been introduced [J. Chem. Phys. 122, 124105 (2005)]. In this article, a formalism for evaluation of analytical Hartree-Fock exchange energy gradients with respect to atomic positions and cell parameters at the Γ-point approximation is presented. While the evaluation of exchange gradients with respect to atomic positions is similar to those in the gas phase limit, the gradients with respect to cell parameters involve the accumulation of atomic gradients multiplied by appropriate factors and a modified electron repulsion integral (ERI). This latter integral arises from use of the minimum image convention in the definition of the Γ-point Hartree-Fock approximation. We demonstrate how this new ERI can be computed with the help of a modified vertical recurrence relation in the frame of the Obara-Saika and Head-Gordon-Pople algorithm. As an illustration, the analytical gradients have been used in conjunction with the QUICCA algorithm [K. Németh and M. Challacombe, J. Chem. Phys. 121, 2877 (2004)] to optimize periodic systems at the Hartree-Fock level of theory.

  11. Lethal effects of experimental warming approximating a future climate scenario on southern African quartz-field succulents: a pilot study.

    PubMed

    Musil, Charles F; Schmiedel, Ute; Midgley, Guy F

    2005-02-01

    Here we examine the response of succulents in a global biodiversity hot spot to experimental warming consistent with a future African climate scenario. Passive daytime warming (averaging 5.5 degrees C above ambient) of the natural vegetation was achieved with 18 transparent hexagonal open-top chamber arrays randomized in three different quartz-field communities. After 4-months summer treatment, the specialized-dwarf and shrubby succulents displayed between 2.1 and 4.9 times greater plant and canopy mortalities in the open-top chambers than in the control plots. Those surviving in cooler ventilated areas and shaded refuges in the chambers had lower starch concentrations and water contents; the shrubby succulents also exhibited diminished chlorophyll concentrations. It is concluded that current thermal regimes are likely to be closely proximate to tolerable extremes for many endemic succulents in the region, and that anthropogenic warming could significantly exceed their thermal thresholds. Further investigation is required to elucidate the importance of associated moisture deficits in these warming experiments, a potential consequence of supplementary (fog and dew) precipitation interception by open-top chambers and higher evaporation therein, on plant mortalities. PMID:15720664

  12. Factors Influencing Elementary Teachers' Positioning of African American Girls as Science and Mathematics Learners

    ERIC Educational Resources Information Center

    Pringle, Rose M.; Brkich, Katie Milton; Adams, Thomasenia Lott; West-Olatunii, Cirecie; Archer-Banks, Diane A.

    2012-01-01

    Despite recent progress toward gender equity in science and mathematics education, the underachievement of low-income African American girls remains a challenge when compared with their white counterparts. Furthermore, the causes of this persistent underachievement have not been explored thoroughly. We have initiated a three-year longitudinal…

  13. Africentric Cultural Values: Their Relation to Positive Mental Health in African American Adolescent Girls

    ERIC Educational Resources Information Center

    Constantine, Madonna G.; Alleyne, Vanessa L.; Wallace, Barbara C.; Franklin-Jackson, Deidre C.

    2006-01-01

    The primary purpose of this study was to test a path model exploring the relationships among Africentric cultural values, self-esteem, perceived social support satisfaction, and life satisfaction in a sample of 147 African American adolescent girls. This investigation also examined the possible mediating effects of self-esteem and perceived social…

  14. African American Faculty Women Experiences of Underrepresentation in Computer Technology Positions in Higher Education

    ERIC Educational Resources Information Center

    King, Dolores

    2013-01-01

    African American women are underrepresented in computer technology disciplines in institutions of higher education throughout the United States. Although equitable gender representation is progressing in most fields, much less information is available on why institutions are still lagging in workforce diversity, a problem which can be lessened by…

  15. Till Death Do Us Part: Lived Experiences of HIV-Positive Married African American Women

    ERIC Educational Resources Information Center

    Edwards, Lorece V.; Irving, Shalon M.; Hawkins, Anita S.

    2011-01-01

    HIV/AIDS disease continues to be an escalating health problem, particularly among women. However, African American women are among the leading demographic groups for HIV prevalence in the United States. The typical woman with HIV/AIDS is young, in her late twenties, economically challenged, and of childbearing age. Participants were recruited from…

  16. South African Educators' Mutually Inclusive Mandates to Promote Human Rights and Positive Discipline

    ERIC Educational Resources Information Center

    Coetzee, Susan; Mienie, Cathrine

    2013-01-01

    South African educators are mandated by international and national law to observe and promote human rights. However, given the realities of the limited teaching time available, educators cannot fulfill this obligation solely by teaching the curriculum. Another avenue needs to be found for educators to fulfill this obligation. Educators are also…

  17. Comparative Transcriptomics of Eastern African Cichlid Fishes Shows Signs of Positive Selection and a Large Contribution of Untranslated Regions to Genetic Diversity

    PubMed Central

    Baldo, Laura; Santos, M.Emília; Salzburger, Walter

    2011-01-01

    The hundreds of endemic species of cichlid fishes in the East African Great Lakes Tanganyika, Malawi, and Victoria are a prime model system in evolutionary biology. With five genomes currently being sequenced, eastern African cichlids also represent a forthcoming genomic model for evolutionary studies of genotype-to-phenotype processes in adaptive radiations. Here we report the functional annotation and comparative analyses of transcriptome data sets for two eastern African cichlid species, Astatotilapia burtoni and Ophthalmotilapia ventralis, representatives of the modern haplochromines and ectodines, respectively. Nearly 647,000 expressed sequence tags were assembled in more than 46,000 contigs for each species using the 454 sequencing technology, largely expanding the current sequence data set publicly available for these cichlids. Total predicted coverage of their proteome diversity is approximately 50% for both species. Comparative qualitative and quantitative analyses show very similar transcriptome data for the two species in terms of both functional annotation and relative abundance of gene ontology terms expressed. Average genetic distance between species is 1.75% when all transcript types are considered including nonannotated sequences, 1.33% for annotated sequences only including untranslated regions, and decreases to nearly half, 0.95%, for coding sequences only, suggesting a large contribution of noncoding regions to their genetic diversity. Comparative analyses across the two species, tilapia and the outgroup medaka based on an overlapping data set of 1,216 genes (∼526 kb) demonstrate cichlid-specific signature of disruptive selection and provide a set of candidate genes that are putatively under positive selection. Overall, these data sets offer the genetic platform for future comparative analyses in light of the upcoming genomes for this taxonomic group. PMID:21617250

  18. Positioning women's and children's health in African union policy-making: a policy analysis

    PubMed Central

    2012-01-01

    Background With limited time to achieve the Millennium Development Goals, progress towards improving women's and children's health needs to be accelerated. With Africa accounting for over half of the world's maternal and child deaths, the African Union (AU) has a critical role in prioritizing related policies and catalysing required investments and action. In this paper, the authors assess the evolution of African Union policies related to women's and children's health, and analyze how these policies are prioritized and framed. Methods The main method used in this policy analysis was a document review of all African Union policies developed from 1963 to 2010, focusing specifically on policies that explicitly mention health. The findings from this document review were discussed with key actors to identify policy implications. Results With over 220 policies in total, peace and security is the most common AU policy topic. Social affairs and other development issues became more prominent in the 1990s. The number of policies that mentioned health rose steadily over the years (with 1 policy mentioning health in 1963 to 7 in 2010). This change was catalysed by factors such as: a favourable shift in AU priorities and systems towards development issues, spurred by the transition from the Organization of African Unity to the African Union; the mandate of the African Commission on Human and People's Rights; health-related advocacy initiatives, such as the Campaign for the Accelerated Reduction of Maternal Mortality in Africa (CARMMA); action and accountability requirements arising from international human rights treaties, the Millennium Development Goals (MDGs), and new health-funding mechanisms, such as the Global Fund to Fight AIDS, Tuberculosis and Malaria. Prioritization of women's and children's health issues in AU policies has been framed primarily by human rights, advocacy and accountability considerations, more by economic and health frames looking at investments and

  19. Selfing ability and dispersal are positively related, but not affected by range position: a multispecies study on southern African Asteraceae.

    PubMed

    de Waal, C; Rodger, J G; Anderson, B; Ellis, A G

    2014-05-01

    Dispersal and breeding system traits are thought to affect colonization success. As species have attained their present distribution ranges through colonization, these traits may vary geographically. Although several theories predict associations between dispersal ability, selfing ability and the relative position of a population within its geographic range, there is little theoretical or empirical consensus on exactly how these three variables are related. We investigated relationships between dispersal ability, selfing ability and range position across 28 populations of 13 annual, wind-dispersed Asteraceae species from the Namaqualand region of South Africa. Controlling for phylogeny, relative dispersal ability--assessed from vertical fall time of fruits--was positively related to an index of autofertility--determined from hand-pollination experiments. These findings support the existence of two discrete syndromes: high selfing ability associated with good dispersal and obligate outcrossing associated with lower dispersal ability. This is consistent with the hypothesis that selection for colonization success drives the evolution of an association between these traits. However, no general effect of range position on dispersal or breeding system traits was evident. This suggests selection on both breeding system and dispersal traits acts consistently across distribution ranges. PMID:24735437

  20. Infected Lives: Lived Experiences of Young African American HIV-Positive Women.

    PubMed

    Peltzer, Jill N; Domian, Elaine W; Teel, Cynthia S

    2016-02-01

    This hermeneutic phenomenological study explored the lived experiences of young African American HIV-infected women. Eleven women between the ages of 21 and 35 participated. One pattern, Infected Lives, and three themes--Living Alone With HIV, Living With Unresolved Conflicts, and Living With Multiple Layers of Betrayal--emerged. The pattern and themes portray the very complex and challenging experiences faced by these young women living with HIV infection. They have experienced isolation, abandonment, betrayal, and discrimination in their interpersonal and social systems. They often dealt with conflicts of hope and anguish in the relationships with their children, and portraying strength, while feeling fragile. These complexities negatively influence the ability to fully engage in self-care activities. Implications for future research include further investigation about the experiences of psychological distress experienced post-diagnosis, development and evaluation of holistic nursing interventions, and evaluative research on mass media educational campaigns to reduce HIV-related stigma. PMID:25239137

  1. Paternal Lifelong Socioeconomic Position and Low Birth Weight Rates: Relevance to the African-American Women's Birth Outcome Disadvantage.

    PubMed

    Collins, James W; Rankin, Kristin M; David, Richard J

    2016-08-01

    Objectives To determine the relation of paternal lifelong socioeconomic position (SEP) to the racial disparity in low birth weight (<2500 g, LBW) rates. Methods Stratified and multilevel logistic regression analyses were performed on an Illinois transgenerational dataset of infants (1989-1991) and their parents (1956-1976) with appended U.S. census income data. The neighborhood incomes of father's place of residence at the time of his birth and at the time of his infant's birth were used to measure of lifelong SEP. Population attributable risk (PAR) percentages were calculated to estimate the percentage of LBW infants attributable to paternal low SEP. Results In Cook County, infants (n = 10,168) born to fathers with a lifelong high SEP had a LBW rate of 3.7 %. LBW rates rose among infants born to fathers with early-life (n = 7224), adulthood (n = 2913), or lifelong (n = 7288) low SEP: 5.2, 6.9, and 9.3 %, respectively. The adjusted (controlling for maternal demographic characteristics) OR of LBW for fathers with an early-life, adulthood, or lifelong low (compared to lifelong high) SEP equaled 1.4 (1.2, 1.6), 1.5 (1.3, 1.9), and 2.0 (1.7, 2.3), respectively. The PAR percentages of LBW for paternal low SEP were 40 and 9 % among African-American and White mothers, respectively. Among fathers with a lifelong high SEP, the adjusted OR of LBW for African-American (compared to White) mothers was 1.1 (0.7, 1.7). Conclusions Low paternal SEP is a novel risk factor for infant LBW independent of maternal demographic characteristics. This phenomenon is particularly relevant to the African-American women's birth outcome disadvantage. PMID:27000848

  2. HIV status disclosure among HIV-positive African and Afro-Caribbean people in the Netherlands.

    PubMed

    Stutterheim, Sarah E; Shiripinda, Iris; Bos, Arjan E R; Pryor, John B; de Bruin, Marijn; Nellen, Jeannine F J B; Kok, Gerjo; Prins, Jan M; Schaalma, Herman P

    2011-02-01

    HIV status disclosure is often characterized as a dilemma. On the one hand, disclosure can promote health, social support, and psychological well-being. On the other, disclosure can lead to stigmatization, rejection, and other negative social interactions. Previous research has shown that HIV status disclosure is a reasoned process whereby the costs and benefits to oneself and to others are weighed. As such, understanding disclosure requires understanding the reasons for and against disclosure employed by people living with HIV (PLWH). In this study, disclosure among a population disproportionately affected by HIV in the Netherlands, namely African and Afro-Caribbean diaspora, was investigated. Reasons for nondisclosure were fear of stigmatization, previous negative experiences with disclosure, having observed the stigmatization of other PLWH, shame, the desire to protect others - particularly one's children and family - from stigmatization by association and/or worrying, and the belief that one's HIV status is a private matter. Participants reported disclosing because they were in a close and supportive relationship, disclosure led to emotional release, disclosure could lead to emotional or financial support, they felt a perceived duty to inform, and they had a desire to educate others about sexual risk-taking. The findings suggest that stigma plays an important role in disclosure decisions among these populations. They further point to a need for HIV-related stigma reduction interventions in African and Afro-Caribbean communities and culturally sensitive counseling for PLWH whereby caregivers do not automatically assume that disclosure is best but rather provide a safe environment in which the costs and benefits of disclosure can be weighed and strategies for disclosure can be developed, if perceived as beneficial by PLWH. PMID:21259132

  3. Signatures of positive selection in East African Shorthorn Zebu: A genome-wide single nucleotide polymorphism analysis

    PubMed Central

    Bahbahani, Hussain; Clifford, Harry; Wragg, David; Mbole-Kariuki, Mary N; Van Tassell, Curtis; Sonstegard, Tad; Woolhouse, Mark; Hanotte, Olivier

    2015-01-01

    The small East African Shorthorn Zebu (EASZ) is the main indigenous cattle across East Africa. A recent genome wide SNP analysis revealed an ancient stable African taurine x Asian zebu admixture. Here, we assess the presence of candidate signatures of positive selection in their genome, with the aim to provide qualitative insights about the corresponding selective pressures. Four hundred and twenty-five EASZ and four reference populations (Holstein-Friesian, Jersey, N’Dama and Nellore) were analysed using 46,171 SNPs covering all autosomes and the X chromosome. Following FST and two extended haplotype homozygosity-based (iHS and Rsb) analyses 24 candidate genome regions within 14 autosomes and the X chromosome were revealed, in which 18 and 4 were previously identified in tropical-adapted and commercial breeds, respectively. These regions overlap with 340 bovine QTL. They include 409 annotated genes, in which 37 were considered as candidates. These genes are involved in various biological pathways (e.g. immunity, reproduction, development and heat tolerance). Our results support that different selection pressures (e.g. environmental constraints, human selection, genome admixture constrains) have shaped the genome of EASZ. We argue that these candidate regions represent genome landmarks to be maintained in breeding programs aiming to improve sustainable livestock productivity in the tropics. PMID:26130263

  4. Signatures of positive selection in East African Shorthorn Zebu: A genome-wide single nucleotide polymorphism analysis.

    PubMed

    Bahbahani, Hussain; Clifford, Harry; Wragg, David; Mbole-Kariuki, Mary N; Van Tassell, Curtis; Sonstegard, Tad; Woolhouse, Mark; Hanotte, Olivier

    2015-01-01

    The small East African Shorthorn Zebu (EASZ) is the main indigenous cattle across East Africa. A recent genome wide SNP analysis revealed an ancient stable African taurine x Asian zebu admixture. Here, we assess the presence of candidate signatures of positive selection in their genome, with the aim to provide qualitative insights about the corresponding selective pressures. Four hundred and twenty-five EASZ and four reference populations (Holstein-Friesian, Jersey, N'Dama and Nellore) were analysed using 46,171 SNPs covering all autosomes and the X chromosome. Following FST and two extended haplotype homozygosity-based (iHS and Rsb) analyses 24 candidate genome regions within 14 autosomes and the X chromosome were revealed, in which 18 and 4 were previously identified in tropical-adapted and commercial breeds, respectively. These regions overlap with 340 bovine QTL. They include 409 annotated genes, in which 37 were considered as candidates. These genes are involved in various biological pathways (e.g. immunity, reproduction, development and heat tolerance). Our results support that different selection pressures (e.g. environmental constraints, human selection, genome admixture constrains) have shaped the genome of EASZ. We argue that these candidate regions represent genome landmarks to be maintained in breeding programs aiming to improve sustainable livestock productivity in the tropics. PMID:26130263

  5. The Impact of Lifecourse Socioeconomic Position on Cardiovascular Disease Events in African Americans: The Jackson Heart Study

    PubMed Central

    Gebreab, Samson Y; Diez Roux, Ana V; Brenner, Allison B; Hickson, DeMarc A; Sims, Mario; Subramanyam, Malavika; Griswold, Michael E; Wyatt, Sharon B; James, Sherman A

    2015-01-01

    Background Few studies have examined the impact of lifecourse socioeconomic position (SEP) on cardiovascular disease (CVD) risk among African Americans. Methods and Results We used data from the Jackson Heart Study (JHS) to examine the associations of multiple measures of lifecourse SEP with CVD events in a large cohort of African Americans. During a median of 7.2-year follow-up, 362 new or recurrent CVD events occurred in a sample of 5301 participants aged 21 to 94. Childhood SEP was assessed by using mother’s education, parental home ownership, and childhood amenities. Adult SEP was assessed by using education, income, wealth, and public assistance. Adult SEP was more consistently associated with CVD risk in women than in men: age-adjusted hazard ratios for low versus high income (95% CIs), 2.46 (1.19 to 5.09) in women and 1.50 (0.87 to 2.58) in men, P for interaction=0.1244, and hazard ratio for low versus high wealth, 2.14 (1.39 to 3.29) in women and 1.06 (0.62 to 1.81) in men, P for interaction=0.0224. After simultaneous adjustment for all adult SEP measures, wealth remained a significant predictor of CVD events in women (HR=1.73 [1.04, 2.85] for low versus high). Education and public assistance were less consistently associated with CVD. Adult SEP was a stronger predictor of CVD events in younger than in older participants (HR for high versus low summary adult SEP score 3.28 [1.43, 7.53] for participants ≤50 years, and 1.90 (1.36 to 2.66) for participants >50 years, P for interaction 0.0846). Childhood SEP was not associated with CVD risk in women or men. Conclusions Adult SEP is an important predictor of CVD events in African American women and in younger African Americans. Childhood SEP was not associated with CVD events in this population. PMID:26019130

  6. Sister to Sister: Dynamics of Mentoring Relationships among African American Women in Leadership and Nonleadership Positions within Higher Education

    ERIC Educational Resources Information Center

    Stiff, MaNesha M.

    2013-01-01

    The purpose of this study was to identify the dynamics of mentoring relationships among African American women within the higher education profession. Utilizing a phenomenological research design, this researcher conducted in-depth interviews with 10 African American women who are mentors and/or mentees of an African American woman in the higher…

  7. HLA-A is a Predictor of Hepatitis B e Antigen Status in HIV-Positive African Adults.

    PubMed

    Matthews, Philippa C; Carlson, Jonathan M; Beloukas, Apostolos; Malik, Amna; Jooste, Pieter; Ogwu, Anthony; Shapiro, Roger; Riddell, Lynn; Chen, Fabian; Luzzi, Graz; Jesuthasan, Gerald; Jeffery, Katie; Jojic, Nebojsa; Ndung'u, Thumbi; Carrington, Mary; Goulder, Philip J R; Geretti, Anna Maria; Klenerman, Paul

    2016-04-15

    Outcomes of chronic infection with hepatitis B virus (HBV) are varied, with increased morbidity reported in the context of human immunodeficiency virus (HIV) coinfection. The factors driving different outcomes are not well understood, but there is increasing interest in an HLA class I effect. We therefore studied the influence of HLA class I on HBV in an African HIV-positive cohort. We demonstrated that virologic markers of HBV disease activity (hepatitis B e antigen status or HBV DNA level) are associated with HLA-A genotype. This finding supports the role of the CD8(+) T-cell response in HBV control, and potentially informs future therapeutic T-cell vaccine strategies. PMID:26655301

  8. HLA-A is a Predictor of Hepatitis B e Antigen Status in HIV-Positive African Adults

    PubMed Central

    Matthews, Philippa C.; Carlson, Jonathan M.; Beloukas, Apostolos; Malik, Amna; Jooste, Pieter; Ogwu, Anthony; Shapiro, Roger; Riddell, Lynn; Chen, Fabian; Luzzi, Graz; Jesuthasan, Gerald; Jeffery, Katie; Jojic, Nebojsa; Ndung'u, Thumbi; Carrington, Mary; Goulder, Philip J. R.; Geretti, Anna Maria; Klenerman, Paul

    2016-01-01

    Outcomes of chronic infection with hepatitis B virus (HBV) are varied, with increased morbidity reported in the context of human immunodeficiency virus (HIV) coinfection. The factors driving different outcomes are not well understood, but there is increasing interest in an HLA class I effect. We therefore studied the influence of HLA class I on HBV in an African HIV-positive cohort. We demonstrated that virologic markers of HBV disease activity (hepatitis B e antigen status or HBV DNA level) are associated with HLA-A genotype. This finding supports the role of the CD8+ T-cell response in HBV control, and potentially informs future therapeutic T-cell vaccine strategies. PMID:26655301

  9. Dependent or Productive? A New Approach to Understanding the Social Positioning of Older South Africans Through Living Arrangements

    PubMed Central

    Madhavan, Sangeetha; Collinson, Mark; Gómez-Olivé, F. Xavier; Ralston, Margaret

    2015-01-01

    South Africa’s population is aging. Most of the older Black South Africans continue to live in extended household structures with children, grandchildren, and other kin. They also constitute a source of income through a means-tested noncontributory state-funded pension available at age 60. Using census data from the Agincourt Health and Demographic Surveillance System in 2000, 2005, and 2010, we develop a typology of living arrangements that is reflective of the social positioning of elderly persons as dependent or productive household members and analyze changes in the distribution over time. Older persons, in general, live in large, complex, and multigenerational households. Multigenerational households with “productive” older persons are increasing in proportion over the period, although there are few differences by gender or pension eligibility at any time point. PMID:25651584

  10. Using novel methods to examine stress among HIV-positive African American men who have sex with men and women.

    PubMed

    Glover, Dorie A; Williams, John K; Kisler, Kimberly A

    2013-06-01

    Biomarker composites (BCs) that objectively quantify psychosocial stress independent of self report could help to identify those at greatest risk for negative health outcomes and elucidate mechanisms of stress-related processes. Here, BCs are examined in the context of existing disease progression among HIV-positive African American men who have sex with men and women (MSMW) with high stress histories, including childhood sexual abuse. Participants (N = 99) collected 12-h overnight and morning urine samples for assay of cortisol and catecholamines (primary BC) and neopterin (an indicator of HIV disease progression). Data on cumulative psychosocial trauma history (severity, types, frequency, age at first incident), posttraumatic stress disorder (PTSD) symptoms, sexual risk behaviors, and a secondary BC consisting of routine health indicators (heart rate, blood pressure, body mass index, waist-to-hip ratio) were also collected. Lifetime trauma exposure was highly pervasive and significantly greater among those meeting a standard cutoff for PTSD caseness (24 %). After controlling for HIV factors (neopterin levels and years with disease), PTSD was a significant (p < .05) predictor of the primary, but not secondary BC. Those with PTSD also had significantly more sexual partners, sex without a condom, and exchange sex for money or drugs than those without PTSD. Specific trauma characteristics predicted PTSD severity and caseness independently and uniquely in regression models (p's < .05-.001). A primary BC appears sensitive to cumulative trauma burden and PTSD in HIV-positive African American MSMW, providing support for the use of BCs to quantify psychosocial stress and inform novel methods for examining mechanisms of stress influenced health behaviors and disease outcomes in at-risk populations. PMID:22538773

  11. Improving adherence to antiretroviral therapy in sub-Saharan African HIV-positive populations: an enhanced adherence package.

    PubMed

    Kunutsor, S; Walley, J; Muchuro, S; Katabira, E; Balidawa, H; Namagala, E; Ikoona, E

    2012-01-01

    With the increasing access to antiretroviral therapy in sub-Saharan African HIV-positive populations, it is important to find additional simple, effective, and feasible methods of improving and maintaining adequately high levels of adherence. In this study, we undertook the development, testing, implementation, and evaluation of various adherence support interventions at four sites in Uganda. A one-group pre- and post-intervention design was employed under routine operational conditions. Various adherence support strategies were identified, adapted, and developed. These strategies which included a combination of elements such as counseling, group education, leaflets, late attendee tracing, and adherence diaries was implemented for an antiretroviral treatment cohort which had baseline levels of adherence measured preintervention. Follow-up was from August 2009 through August 2010. Mean adherence and proportions of clients achieving adherence levels of 95% and above were determined at end of follow-up. Of the 967 participants enrolled, 856 (88.5%) completed follow-up. A before-and-after comparison of outcomes demonstrated that mean adherence (95% confidence interval [CI]) improved statistically significant from baseline following implementation of the interventions (97.4% [96.9-97.9%] to 99.1% [99.0-99.3%], P=0.001). There was also a significant difference between proportions with optimal (≥ 95%) and suboptimal adherence (<95%) pre- and post-intervention (7.0% difference, 95% CI: 4.6-9.4%, P<0.001). We conclude that additional adherence strategies (including counseling, group education, leaflets, late attendee tracing, and adherence diaries) can substantially improve and maintain high levels of treatment adherence in the long term. Health systems in sub-Saharan African countries should consider integrating these elements into their treatment programs for HIV/AIDS. PMID:22621288

  12. Cigarette Smoking among African American Youth from Single Mother Homes: Examining the Roles of Maternal Smoking and Positive Parenting within an Extended Family Framework

    ERIC Educational Resources Information Center

    Foster, Sarah E.; Zalot, Alecia A.; Jones, Deborah J.

    2007-01-01

    The current study examined the main and interactive effects of three family context variables, maternal smoking, positive parenting behavior, and the quality of the mother's relationship with another adult or family member who assists with parenting (i.e., coparent), and adolescent smoking among African American youth from single mother homes. The…

  13. Hiring Practices of African American Males in Academic Leadership Positions at American Colleges and Universities: An Employment Trends and Disparate Impact Analysis

    ERIC Educational Resources Information Center

    Jackson, Jerlando F. L.

    2006-01-01

    This study examined the status of African American males in academic leadership positions at American colleges and universities in comparison with other males (e.g., Asian). Guided by disparate impact theory, descriptive trend analyses and impact ratios were computed using the 1993 and 1999 National Study of Postsecondary Faculty (NSOPF). These…

  14. A Test of the Tripartite Model of Career Indecision of Brown and Krane for African Americans Incorporating Emotional Intelligence and Positive Affect

    ERIC Educational Resources Information Center

    Hammond, Marie S.; Lockman, Jennifer D.; Boling, Timothy

    2010-01-01

    Brown and Krane have posited a tripartite model of career indecision, which includes three higher order factors: negative affect, poor vocational identity development, and lack of career information. The purpose of this study was to examine the adequacy of their tripartite model of career indecision for African American students, considering that…

  15. The Process of Adaptation of a Community-Level, Evidence-Based Intervention for HIV-Positive African American Men Who Have Sex with Men in Two Cities

    ERIC Educational Resources Information Center

    Robinson, Beatrice E.; Galbraith, Jennifer S.; Lund, Sharon M.; Hamilton, Autumn R.; Shankle, Michael D.

    2012-01-01

    We describe the process of adapting a community-level, evidence-based behavioral intervention (EBI), Community PROMISE, for HIV-positive African American men who have sex with men (AAMSM). The Centers for Disease Control and Prevention (CDC) Map of the Adaptation Process (MAP) guided the adaptation process for this new target population by two…

  16. Evolution of the pygmy phenotype: evidence of positive selection fro genome-wide scans in African, Asian, and Melanesian pygmies.

    PubMed

    Migliano, Andrea Bamberg; Romero, Irene Gallego; Metspalu, Mait; Leavesley, Matthew; Pagani, Luca; Antao, Tiago; Huang, Da-Wei; Sherman, Brad T; Siddle, Katharine; Scholes, Clarissa; Hudjashov, Georgi; Kaitokai, Elton; Babalu, Avis; Belatti, Maggie; Cagan, Alex; Hopkinshaw, Byrony; Shaw, Colin; Nelis, Mari; Metspalu, Ene; Mägi, Reedik; Lempicki, Richard A; Villems, Richard; Lahr, Marta Mirazon; Kivisild, Toomas

    2013-01-01

    Human pygmy populations inhabit different regions of the world, from Africa to Melanesia. In Asia, short-statured populations are often referred to as "negritos." Their short stature has been interpreted as a consequence of thermoregulatory, nutritional, and/or locomotory adaptations to life in tropical forests. A more recent hypothesis proposes that their stature is the outcome of a life history trade-off in high-mortality environments, where early reproduction is favored and, consequently, early sexual maturation and early growth cessation have coevolved. Some serological evidence of deficiencies in the growth hormone/insulin-like growth factor axis have been previously associated with pygmies' short stature. Using genome-wide single-nucleotide polymorphism genotype data, we first tested whether different negrito groups living in the Philippines and Papua New Guinea are closely related and then investigated genomic signals of recent positive selection in African, Asian, and Papuan pygmy populations. We found that negritos in the Philippines and Papua New Guinea are genetically more similar to their nonpygmy neighbors than to one another and have experienced positive selection at different genes. These results indicate that geographically distant pygmy groups are likely to have evolved their short stature independently. We also found that selection on common height variants is unlikely to explain their short stature and that different genes associated with growth, thyroid function, and sexual development are under selection in different pygmy groups. PMID:24297229

  17. Status Needs Positive Change. Report of the Subcommittee on the Immigrant Community of African Descent. Volume 4, Immigrants of African Descent.

    ERIC Educational Resources Information Center

    New York Governor's Advisory Committee for Black Affairs, Albany.

    This document comprises an analysis of the needs of immigrants of African descent to New York State in the following areas: (1) economic planning; (2) culture and the arts; (3) immigration reform and amnesty; and (4) health care. Immigrants from the Caribbean and Africa comprise rapidly growing segments of the State's population. These immigrants…

  18. Positive and negative effects of grass, cattle, and wild herbivores on Acacia saplings in an East African savanna.

    PubMed

    Riginos, Corinna; Young, Truman P

    2007-10-01

    Plant-plant interactions can be a complex mixture of positive and negative interactions, with the net outcome depending on abiotic and community contexts. In savanna systems, the effects of large herbivores on tree-grass interactions have rarely been studied experimentally, though these herbivores are major players in these systems. In African savannas, trees often become more abundant under heavy cattle grazing but less abundant in wildlife preserves. Woody encroachment where cattle have replaced wild herbivores may be caused by a shift in the competitive balance between trees and grasses. Here we report the results of an experiment designed to quantify the positive, negative, and net effects of grasses, wild herbivores, and cattle on Acacia saplings in a Kenyan savanna. Acacia drepanolobium saplings under four long-term herbivore regimes (wild herbivores, cattle, cattle + wild herbivores, and no large herbivores) were cleared of surrounding grass or left with the surrounding grass intact. After two years, grass-removal saplings exhibited 86% more browse damage than control saplings, suggesting that grass benefited saplings by protecting them from herbivory. However, the negative effect of grass on saplings was far greater; grass-removal trees accrued more than twice the total stem length of control trees. Where wild herbivores were present, saplings were browsed more and produced more new stem growth. Thus, the net effect of wild herbivores was positive, possibly due to the indirect effects of lower competitor tree density in areas accessible to elephants. Additionally, colonization of saplings by symbiotic ants tracked growth patterns, and colonized saplings experienced lower rates of browse damage. These results suggest that savanna tree growth and woody encroachment cannot be predicted by grass cover or herbivore type alone. Rather, tree growth appears to depend on a variety of factors that may be acting together or antagonistically at different stages of the

  19. "The Blues Playingest Dog You Ever Heard Of": (Re)positioning Literacy through African American Blues Rhetoric

    ERIC Educational Resources Information Center

    Kynard, Carmen

    2008-01-01

    Building on scholarship in African American rhetorics and African American language, an analysis of Walter Dean Myers's (2000) "The Blues of Flats Brown" is presented as a methodology for (re)imagining educational issues and research related to voice, agency, reading, and literacy in the face of racial oppression and subjugation. In the analysis,…

  20. Reconsidering the Relationship between Race and Crime: Positive and Negative Predictors of Crime among African American Youth

    ERIC Educational Resources Information Center

    Entner Wright, Bradley R.; Younts, C. Wesley

    2009-01-01

    Studies of race and crime have emphasized the effects of social disadvantage and discrimination on increasing crime among African Americans. The authors extend this literature by examining various beliefs and institutions that have developed within African American communities that, in contrast, decrease criminal behavior. A model of…

  1. HIV-positive African-American women's perspectives on engaging communities in the response to HIV/AIDS in Washington, D.C.

    PubMed

    Sanicki, Anne; Mannell, Jenevieve

    2015-01-01

    The number of African-American women infected with HIV in Washington, D.C. is growing at an alarming rate. However, the perspectives of these women on engaging communities in the response to HIV/AIDS have been lacking in the literature. To fill this gap, in-depth interviews with 18 HIV-positive African-American women living in D.C. were conducted and analyzed using thematic network analysis. Three key themes emerged from these interviews: (1) the importance of the church in building HIV/AIDS community competence; (2) women's interest in HIV/AIDS advocacy; and (3) the negative effects of stigma and limited social bonds on community engagement. We conclude by suggesting that more research is needed on the role of African-American women in community capacity building, as well as greater involvement of churches in HIV/AIDS responses. PMID:26208602

  2. Differential Predictors of Medication Adherence in HIV: Findings from a Sample of African American and Caucasian HIV-Positive Drug-Using Adults

    PubMed Central

    Moizel, Jennifer; Panos, Stella E.; Patel, Sapna M.; Byrd, Desiree A.; Myers, Hector F.; Wyatt, Gail E.; Hinkin, Charles H.

    2012-01-01

    Abstract Modest or even occasional nonadherence to combined antiretroviral therapy (cART) can result in adverse clinical outcomes. African Americans demonstrate lower rates of adherence than Caucasians or Latinos. Identifying factors that influence medication adherence among African Americans is a critical step toward reducing HIV/AIDS disease progression and mortality. In a sample of 181 African American (n=144) and Caucasian (n=37) HIV-positive drug-using individuals [age (M=42.31; SD=6.6) education (M=13.41; SD=2.1)], we examined the influence of baseline drug use, literacy, neurocognition, depression, treatment-specific social support, and patient satisfaction with health care provider on medication adherence averaged over the course of 6 months (study dates 2002–2006). Our findings suggest differential baseline predictors of medication adherence for African Americans and Caucasians, such that patient satisfaction with provider was the strongest predictor of follow-up medication adherence for African Americans whereas for Caucasians depressive symptoms and treatment-specific social support were predictive of medication adherence (after controlling for duration of drug use). PMID:22889235

  3. Socioeconomic Position, But Not African Genomic Ancestry, Is Associated With Blood Pressure in the Bambui-Epigen (Brazil) Cohort Study of Aging.

    PubMed

    Lima-Costa, M Fernanda; Mambrini, Juliana Vaz de Mello; Leite, Maria Lea Corrêa; Peixoto, Sérgio Viana; Firmo, Josélia Oliveira Araújo; Loyola Filho, Antônio Ignácio de; Gouveia, Mateus H; Leal, Thiago P; Pereira, Alexandre Costa; Macinko, James; Tarazona-Santos, Eduardo

    2016-02-01

    The study objective is to examine the role of African genome origin on baseline and 11-year blood pressure trajectories in community-based ethnoracially admixed older adults in Brazil. Data come from 1272 participants (aged ≥60 years) of the Bambui cohort study of aging during 11 years of follow-up. Outcome measures were systolic blood pressure, diastolic blood pressure, and hypertension control. Potential confounding variables were demographic characteristics, socioeconomic position (schooling and household income), and health indicators (smoking, sedentary lifestyle, high-density lipoprotein cholesterol, waist circumference, diabetes mellitus, and cardiovascular diseases), including antihypertensive drug use. We used 370 539 single-nucleotide polymorphisms to estimate each individual's African, European, and Native American trihybrid ancestry proportions. Median African, European, and Native American ancestry were 9.6%, 84.0%, and 5.3%, respectively. Among those with African ancestry, 59.4% came from East and 40.6% from West Africa. Baseline systolic and diastolic blood pressure, controlled hypertension, and their respective trajectories, were not significantly (P>0.05) associated with level (in quintiles) of African genomic ancestry. Similar results were found for West and East African subcontinental origins. Lower schooling level (<4 years versus higher) showed a significant and positive association with systolic blood pressure (Adjusted β=2.92; 95% confidence interval, 0.85-4.99). Lower monthly household income per capita (

  4. HIV Stigma and Missed Medications in HIV-Positive People in Five African Countries

    PubMed Central

    Dlamini, Priscilla S.; Wantland, Dean; Makoae, Lucy N.; Chirwa, Maureen; Kohi, Thecla W.; Greeff, Minrie; Naidoo, Joanne; Mullan, Joseph; Uys, Leana R.

    2009-01-01

    Abstract The availability of antiretroviral medications has transformed living with HIV infection into a manageable chronic illness, and high levels of adherence are necessary. Stigma has been identified as one reason for missing medication doses. The objective of this study was to explore the relationship between perceived HIV stigma and self-reported missed doses of antiretroviral medications in a 12-month, repeated measures cohort study conducted in Lesotho, Malawi, South Africa, Swaziland, and Tanzania. Data were collected from 1457 HIV-positive individuals at three times between January 2006 and March 2007. Participants completed a series of questionnaires. Of the 1457 participants, 698 were taking ARVs during the study and are included in this analysis. There was a significant relationship between perceived HIV stigma and self-report of missed medications over time (t = 6.04, p ≤ 0.001). Individuals who reported missing more ARV medications also reported higher levels of perceived HIV stigma. Individuals reporting fewer medication worries reported decreased stigma over the one year period (t = −4.79, p ≤ 0.001). While those who reported increased symptom intensity also reported increased stigma initially (t = 8.67, p ≤ 0.001) that remained high over time. This study provides evidence of a significant and stable correlation that documents the relationship between perceived HIV stigma and self-reported reasons for missed medications over time. These findings suggest that part of the reason for poor adherence to ARV medications is linked to the stigma experienced by people living with HIV. PMID:19327098

  5. HIV stigma and missed medications in HIV-positive people in five African countries.

    PubMed

    Dlamini, Priscilla S; Wantland, Dean; Makoae, Lucy N; Chirwa, Maureen; Kohi, Thecla W; Greeff, Minrie; Naidoo, Joanne; Mullan, Joseph; Uys, Leana R; Holzemer, William L

    2009-05-01

    The availability of antiretroviral medications has transformed living with HIV infection into a manageable chronic illness, and high levels of adherence are necessary. Stigma has been identified as one reason for missing medication doses. The objective of this study was to explore the relationship between perceived HIV stigma and self-reported missed doses of antiretroviral medications in a 12-month, repeated measures cohort study conducted in Lesotho, Malawi, South Africa, Swaziland, and Tanzania. Data were collected from 1457 HIV-positive individuals at three times between January 2006 and March 2007. Participants completed a series of questionnaires. Of the 1457 participants, 698 were taking ARVs during the study and are included in this analysis. There was a significant relationship between perceived HIV stigma and self-report of missed medications over time (t = 6.04, p

  6. WiLLOW: Reaching HIV-Positive African-American Women Through a Computer-Delivered Intervention

    PubMed Central

    Klein, Charles H.; Lomonaco, Carmela G.; Pavlescak, Rik; Card, Josefina J.

    2013-01-01

    WiLLOW is an evidence-based, group level HIV prevention program for African-American women living with HIV. This study evaluated the efficacy of a multimedia adaptation of WiLLOW in enhancing protective sexual behaviors and psychosocial mediators associated with HIV risk reduction. Using a randomized controlled design, 168 participants completed baseline, satisfaction, and three-month follow-up assessments. At follow-up intervention participants reported higher proportions of condom protected sex acts (p = .002) with both HIV-negative (p = .040) and HIV-positive (p = .003) partners. They were also more likely to report 100 % condom use (OR = 9.67; p = .03); fewer unprotected vaginal and anal sex acts (p = .002); significantly greater sexual communication self-efficacy (p = .004); and less stress (p = .012). Participants rated Multimedia WiLLOW favorably in four satisfaction categories—enjoyment (p < .001); information utility (p = .018); information clarity (p = .015) and held attention (p = .01). PMID:23625384

  7. Image versus Health: The Role of Perceptions of Masculinity on Sexual Risk Behaviors among HIV-Positive African American Men who have Sex with Men and Women

    PubMed Central

    Kisler, Kimberly A.; Williams, John K.

    2013-01-01

    Background HIV prevention has rarely explored the impact of childhood sexual abuse (CSA) across health domains among African American men who have sex with men and women (MSMW). Early sexual experiences may influence perceptions of gender roles, sexual identity, and risks for HIV/AIDS. The attribute of masculinity is commonly associated with strength and success. However, a legacy of racism and oppression may pose challenges for African American men in achieving gender-based milestones. Instead, proxies for success may include masculinity constructs with hypersexual posturing and prowess that contradict sexual health messages. Methods Two groups, each meeting twice for 90-minutes, of HIV-positive African American MSMW participated in discussions focusing on masculinity and sexual experiences. Participants were bisexual HIV-positive African American men who engaged in unprotected sex and had histories of CSA. Discussions were recorded, transcribed, and analyzed using consensual qualitative research and a constant comparison qualitative method. Results Participant mean age was 40.5 years (n=16). Majority had a high school education (69%), half were unemployed, and almost two-thirds earned less than $20,000 annually. Three themes, each with two subthemes, emerged that described the sociocultural context for engaging in high-risk sexual behaviors, and included: 1) the importance of inhabiting a “traditional” masculine gender role with: a) general and b) sexual masculine traits; 2) the influence of conceptions of masculinity on sexual identity with the associations: a) between being gay and being effeminate and b) between being gay and being HIV-positive, and; 3) CSA experiences with: a) appraisal of CSA and b) early sexual experiences as rites of passage. Conclusion Attempts to be masculine may contribute to high-risk sexual behaviors. Research needs to explore how early sexual experiences shape perceptions of masculinity and masculinity's influence on receiving

  8. The Education of African-American Learners with Behavior Disorders: An Unresolved Issue for General and Special Educators. Position Paper.

    ERIC Educational Resources Information Center

    Obiakor, Festus E.

    This paper addresses critical questions concerning the educational needs of African American students with behavior disorders. These include: the historical context; effects of reform and restructuring movements on this population; the unresolved issue of defining "seriously emotionally disturbed" or "emotional or behavior disorder"; the failure…

  9. Valuing the "Everyday" Practices of African American Students K-12 and Their Engagement in STEM Learning: A Position

    ERIC Educational Resources Information Center

    Wright, Brian L.

    2011-01-01

    This article is a call to the research community to look again at the "everyday" or community-based meaning-making practices--ways of seeing, knowing, talking, acting, valuing, representing--that African American students K-12 use routinely in navigating everyday life out of school and how these relate to learning and achievement in science and…

  10. Factors that Enable Women of South Asian and African Descent to Succeed in Leadership Positions in Higher Education

    ERIC Educational Resources Information Center

    Kamassah, Sharon

    2010-01-01

    This research study focused on the factors that enable women of South Asian and African descent to succeed as leaders in the college system. The findings were derived from online questionnaires and in-depth interviews of 16 racialized women from two Greater Toronto Area (GTA) colleges. Many factors and recommendations were shared. Some of the…

  11. On the accuracy of approximation of a small celestial body motion using intermediate perturbed orbits calculated from two position vectors and three observations

    NASA Astrophysics Data System (ADS)

    Shefer, V. A.; Shefer, O. V.

    2015-01-01

    We examine intermediate perturbed orbits proposed by the first author previously, defined from the two position vectors and three angular coordinates of a small celestial body. It is shown theoretically, that at a small reference time interval covering the measurements the approximation accuracy of real movements by these orbits corresponds approximately to the third order of osculation. The smaller reference interval of time, the better this correspondence. Laws of variation of the methodical errors in constructing intermediate orbits subject to the length of reference time interval are deduced. According to these laws, the convergence rate of the methods to the exact solution (upon reducing the reference interval of time) is higher by two orders of magnitude than in the case of conventional methods using the Keplerian unperturbed orbit. The considered orbits are among the most accurate in set of orbits of their class determined by the order of osculation. The theoretical results are validated by numerical examples.

  12. Positioning.

    ERIC Educational Resources Information Center

    Conone, Ruth M.

    The key to positioning is the creation of a clear benefit image in the consumer's mind. One positioning strategy is creating in the prospect's mind a position that takes into consideration the company's or agency's strengths and weaknesses as well as those of its competitors. Another strategy is to gain entry into a position ladder owned by…

  13. Discrimination and Hate Crimes in the Context of Neighborhood Poverty and Stressors Among HIV-Positive African-American Men Who Have Sex with Men.

    PubMed

    Dale, Sannisha K; Bogart, Laura M; Galvan, Frank H; Wagner, Glenn J; Pantalone, David W; Klein, David J

    2016-06-01

    In a sample of HIV-positive African-American men who have sex with men (MSM), we examined neighborhood factors that may contextualize perceived discrimination from three intersecting stigmatized characteristics: race, HIV status, and sexual orientation. HIV-positive African-American MSM (N = 162, mean age = 44, SD = 8) provided information on neighborhood-related stressors and discrimination experiences related to being Black, HIV-positive, or perceived as gay. Residential ZIP codes and US Census data were used to determine neighborhood poverty rates. Regressions, controlling for socio-demographics, indicated that (1) higher neighborhood poverty was significantly related to more frequent experiences with hate crimes (Gay-related: b = 1.15, SE = .43, p < .008); and (2) higher neighborhood-related stressors were significantly related to more frequent discrimination (Black-related: b = .91, SE = .28, p = .001; gay-related: b = .71, SE = .29, p = .01; and HIV-related: b = .65, SE = .28, p = .02) and hate crimes (Gay-related: b = .48, SE = .13, p = .001; and Black-related: b = .28, SE = .14, p = .04). For HIV-positive African-American MSM, higher neighborhood poverty and related stressors are associated with experiencing more discrimination and hate crimes. Interventions for this group should promote individual- and neighborhood-level socioeconomic empowerment and stigma reduction. PMID:26696119

  14. Whole-genome sequence analyses of Western Central African Pygmy hunter-gatherers reveal a complex demographic history and identify candidate genes under positive natural selection.

    PubMed

    Hsieh, PingHsun; Veeramah, Krishna R; Lachance, Joseph; Tishkoff, Sarah A; Wall, Jeffrey D; Hammer, Michael F; Gutenkunst, Ryan N

    2016-03-01

    African Pygmies practicing a mobile hunter-gatherer lifestyle are phenotypically and genetically diverged from other anatomically modern humans, and they likely experienced strong selective pressures due to their unique lifestyle in the Central African rainforest. To identify genomic targets of adaptation, we sequenced the genomes of four Biaka Pygmies from the Central African Republic and jointly analyzed these data with the genome sequences of three Baka Pygmies from Cameroon and nine Yoruba famers. To account for the complex demographic history of these populations that includes both isolation and gene flow, we fit models using the joint allele frequency spectrum and validated them using independent approaches. Our two best-fit models both suggest ancient divergence between the ancestors of the farmers and Pygmies, 90,000 or 150,000 yr ago. We also find that bidirectional asymmetric gene flow is statistically better supported than a single pulse of unidirectional gene flow from farmers to Pygmies, as previously suggested. We then applied complementary statistics to scan the genome for evidence of selective sweeps and polygenic selection. We found that conventional statistical outlier approaches were biased toward identifying candidates in regions of high mutation or low recombination rate. To avoid this bias, we assigned P-values for candidates using whole-genome simulations incorporating demography and variation in both recombination and mutation rates. We found that genes and gene sets involved in muscle development, bone synthesis, immunity, reproduction, cell signaling and development, and energy metabolism are likely to be targets of positive natural selection in Western African Pygmies or their recent ancestors. PMID:26888263

  15. Whole-genome sequence analyses of Western Central African Pygmy hunter-gatherers reveal a complex demographic history and identify candidate genes under positive natural selection

    PubMed Central

    Hsieh, PingHsun; Veeramah, Krishna R.; Lachance, Joseph; Tishkoff, Sarah A.; Wall, Jeffrey D.; Hammer, Michael F.; Gutenkunst, Ryan N.

    2016-01-01

    African Pygmies practicing a mobile hunter-gatherer lifestyle are phenotypically and genetically diverged from other anatomically modern humans, and they likely experienced strong selective pressures due to their unique lifestyle in the Central African rainforest. To identify genomic targets of adaptation, we sequenced the genomes of four Biaka Pygmies from the Central African Republic and jointly analyzed these data with the genome sequences of three Baka Pygmies from Cameroon and nine Yoruba famers. To account for the complex demographic history of these populations that includes both isolation and gene flow, we fit models using the joint allele frequency spectrum and validated them using independent approaches. Our two best-fit models both suggest ancient divergence between the ancestors of the farmers and Pygmies, 90,000 or 150,000 yr ago. We also find that bidirectional asymmetric gene flow is statistically better supported than a single pulse of unidirectional gene flow from farmers to Pygmies, as previously suggested. We then applied complementary statistics to scan the genome for evidence of selective sweeps and polygenic selection. We found that conventional statistical outlier approaches were biased toward identifying candidates in regions of high mutation or low recombination rate. To avoid this bias, we assigned P-values for candidates using whole-genome simulations incorporating demography and variation in both recombination and mutation rates. We found that genes and gene sets involved in muscle development, bone synthesis, immunity, reproduction, cell signaling and development, and energy metabolism are likely to be targets of positive natural selection in Western African Pygmies or their recent ancestors. PMID:26888263

  16. Positive parenting and child psychosocial adjustment in inner-city single-parent African American families. The role of maternal optimism.

    PubMed

    Jones, Deborah J; Forehand, Rex; Brody, Gene H; Armistead, Lisa

    2002-09-01

    The primary purposes of this study were to examine whether maternal optimism is related to positive parenting and child adjustment and whether it contributes beyond maternal depressive symptoms to our understanding. The participants were 141 African American single mothers and one of their children. Findings revealed that maternal optimism was associated with positive parenting and this association was only partially mediated by maternal depressive symptoms. Maternal optimism was not associated with child psychosocial adjustment, but positive parenting was associated with lower levels of both internalizing and externalizing difficulties. The utility of understanding the link between maternal optimism and parenting for prevention and intervention efforts aimed at enhancing quality of life and subsequent child adjustment is discussed, as well as directions for future research on maternal optimism. PMID:12205822

  17. On the accuracy of approximation of motion of a small celestial body by intermediate perturbed orbits calculated on the basis of three position vectors and three observations

    NASA Astrophysics Data System (ADS)

    Shefer, V. A.; Shefer, O. V.

    2016-05-01

    Intermediate perturbed orbits, which were proposed earlier by the first author and are calculated based on three position vectors and three measurements of angular coordinates of a small celestial body, are examined. Provided that the reference time interval encompassing the measurements is short, these orbits are close in the accuracy of approximation of actual motion to an orbit with fourth-order tangency. The shorter the reference time interval is, the better is the approximation. The laws of variation of the errors of methods for constructing such intermediate orbits with the length of the reference time interval are formulated. According to these laws, the rate of convergence of the methods to an exact solution in the process of shortening of the reference time interval is, in general, three orders of magnitude higher than that of conventional methods relying on an unperturbed Keplerian orbit. The considered orbits are among the most accurate of their class that is defined by the order of tangency. The obtained theoretical results are verified by numerical experiments on determining the orbit of 99942 Apophis.

  18. Relationship between Housing Status and Retention Rates among HIV-Positive African Americans Enrolled in a Comprehensive Care Program.

    PubMed

    Xiao, Hong; Mains, William

    2016-01-01

    Service provision using "one-stop shopping" of medical, psychiatric, and case management services at the same location has been associated with superior client retention. The Yadumu project tested this premise, with attention to HIV-infected African Americans. Each client was assigned a case manager, who arranged meetings with mental health, substance abuse, and medical care professionals. The Center for Mental Health Services, National Outcome Measures (CMHS NOMs) questionnaire was used to evaluate client progress. Data were collected longitudinally and the program evaluation was performed by an outside center. Among 129 clients, 47% were male, 30% were female, and 22% were transgender. The majority (72%) were African American. Clients who lived in detox/drug treatment programs had higher completion rates (48%) than those who were homeless or otherwise housed (28%) (p = 0.04). Logistic regression was used to assess associations between independent factors and retention. Clients satisfied with their housing situation were less likely to retain in the program than those who were not satisfied with their housing situation (OR = 0.15, 95% CI: 0.03-0.78). High discharge rates among HIV-infected people were observed and may reflect the unstable circumstances of the population studied, but structured residential programs could be advantageous for improving retention. PMID:26960017

  19. African and non-African admixture components in African Americans and an African Caribbean population.

    PubMed

    Murray, Tanda; Beaty, Terri H; Mathias, Rasika A; Rafaels, Nicholas; Grant, Audrey Virginia; Faruque, Mezbah U; Watson, Harold R; Ruczinski, Ingo; Dunston, Georgia M; Barnes, Kathleen C

    2010-09-01

    Admixture is a potential source of confounding in genetic association studies, so it becomes important to detect and estimate admixture in a sample of unrelated individuals. Populations of African descent in the US and the Caribbean share similar historical backgrounds but the distributions of African admixture may differ. We selected 416 ancestry informative markers (AIMs) to estimate and compare admixture proportions using STRUCTURE in 906 unrelated African Americans (AAs) and 294 Barbadians (ACs) from a study of asthma. This analysis showed AAs on average were 72.5% African, 19.6% European and 8% Asian, while ACs were 77.4% African, 15.9% European, and 6.7% Asian which were significantly different. A principal components analysis based on these AIMs yielded one primary eigenvector that explained 54.04% of the variation and captured a gradient from West African to European admixture. This principal component was highly correlated with African vs. European ancestry as estimated by STRUCTURE (r(2)=0.992, r(2)=0.912, respectively). To investigate other African contributions to African American and Barbadian admixture, we performed PCA on approximately 14,000 (14k) genome-wide SNPs in AAs, ACs, Yorubans, Luhya and Maasai African groups, and estimated genetic distances (F(ST)). We found AAs and ACs were closest genetically (F(ST)=0.008), and both were closer to the Yorubans than the other East African populations. In our sample of individuals of African descent, approximately 400 well-defined AIMs were just as good for detecting substructure as approximately 14,000 random SNPs drawn from a genome-wide panel of markers. PMID:20717976

  20. Multiproxy Evidence for a Positive Hydrological Budget during the Little Ice Age in the East African Rift, Kenya

    NASA Astrophysics Data System (ADS)

    Goman, M.; Ashley, G. M.; Hover, V. C.; Owen, R.

    2011-12-01

    Hominin evolution took place in Africa during the Plio-Pleistocene and climate change is thought to be a factor, with Africa experiencing a general cooling and increasing aridification over the last several million years. Today, the climate of the East African Rift Valley of Kenya is characterized as semi-arid with evapotranspiration four times precipitation. Water resources are a valuable commodity for the many millions of inhabitants of the Valley. The short instrumental record shows precipitation fluctuates at sub-decadal timeframes as a result of the ENSO cycle; while during prehistory variations in monsoonal precipitation occurred on Milankovitch timescales (i.e. African Humid Period). Both timescales exhibit significant impacts on the distribution of surface water. However, little is known regarding precipitation variability over sub-millennial timescales. Emerging paleoclimate data indicates that the near surface presence of water has also varied over century length timescales. We present paleoclimate data from multiple sites along a north-south 600 km transect of the Gregory Rift Valley (Kenya) that indicate the region experienced wetter conditions during the Little Ice Age (A.D. 1400-1850). Our reconstructions of landscape and climate during this time frame rely upon a multiproxy and interdisciplinary approach. We discuss data from a variety of environmental settings (e.g. lakes, wetlands, and springs) that indicate an overall increase in hydrologic balance. Evidence is derived from biologic microfossils such as pollen, diatom and testate amoebae assemblages as well as inorganic components of the sedimentary record and geomorphic changes. The data differs significantly from studies undertaken to the west in Uganda and the Congo, where negative hydrologic balances occurred during the Little Ice Age. While the atmospheric dynamics causing this disparity are not yet recognized, interactions between the Intertropical Convergence Zone and the Congo Air Boundary

  1. The Results of the “Positive Action for Today’s Health” (PATH) Trial for Increasing Walking and Physical Activity in Underserved African-American Communities

    PubMed Central

    Wilson, Dawn K.; Van Horn, M. Lee; Siceloff, E. Rebekah; Alia, Kassandra A.; St. George, Sara M.; Lawman, Hannah G.; Trumpeter, Nevelyn N.; Coulon, Sandra M.; Griffin, Sarah F.; Wandersman, Abraham; Egan, Brent; Colabianchi, Natalie; Forthofer, Melinda; Gadson, Barney

    2015-01-01

    Background The “Positive Action for Today’s Health” (PATH) trial tested an environmental intervention to increase walking in underserved communities. Methods Three matched communities were randomized to a police-patrolled walking plus social marketing, a police-patrolled walking-only, or a no-walking intervention. The 24-month intervention addressed safety and access for physical activity (PA) and utilized social marketing to enhance environmental supports for PA. African-Americans (N=434; 62 % females; aged 51±16 years) provided accelerometry and psychosocial measures at baseline and 12, 18, and 24 months. Walking attendance and trail use were obtained over 24 months. Results There were no significant differences across communities over 24 months for moderate-to-vigorous PA. Walking attendance in the social marketing community showed an increase from 40 to 400 walkers per month at 9 months and sustained ~200 walkers per month through 24 months. No change in attendance was observed in the walking-only community. Conclusions Findings support integrating social marketing strategies to increase walking in underserved African-Americans (ClinicalTrials.gov #NCT01025726). PMID:25385203

  2. Too much of a good thing?: Positive religious coping predicts worse diurnal salivary cortisol patterns for overwhelmed African-American female dementia family caregivers

    PubMed Central

    Merritt, Marcellus M.; McCallum, T. J.

    2012-01-01

    Objectives Religious coping arguably prevents negative health outcomes for stressed persons. This study examined the moderating role of religious coping (positive, negative, and combined) in the connection of care recipient functional status with diurnal salivary cortisol patterns among dementia family caregivers. Methods Thirty African-American (AA) female dementia caregivers and 48 AA noncaregivers completed the Religious Coping (RCOPE) scale, Activities of Daily Living (ADL) scale and Revised Memory and Behavior Problem checklist (RMBPC) and collected five saliva samples daily (at awakening, 9am, 12pm, 5pm, and 9pm) for two straight days. Results Hierarchical regression tests with mean diurnal cortisol slope as the outcome illustrated surprisingly that higher combined and positive (but not negative) RCOPE scores were associated with increasingly flatter or worse cortisol slope scores for caregivers (but not non-caregivers). Of note, the RCOPE by RMBPC interaction was significant. Among caregivers who reported higher RMBPC scores, higher combined and positive (but not negative) RCOPE scores were unexpectedly associated with increasingly flatter cortisol slopes. Conclusions These results extend current findings by showing that being AA, a caregiver, and high in positive religious coping may predict increased daily stress responses, mainly for those with higher patient behavioral problems. Since religious coping is a central coping strategy for AA caregivers, it is vital that epidemiological assessments of religious coping in health and aging as well as tailored interventions focus on the unique reasons for this disparity. PMID:23290202

  3. The Experience of Antiretroviral Treatment for Black West African Women who are HIV Positive and Living in London: An Interpretative Phenomenological Analysis.

    PubMed

    Spiers, Johanna; Smith, Jonathan A; Poliquin, Elizabeth; Anderson, Jane; Horne, Rob

    2016-09-01

    Antiretroviral therapy (ART) offers a powerful intervention in HIV but effectiveness can be compromised by inadequate adherence. This paper is a detailed examination of the experience of medication in a purposively selected group of people living with HIV. In-depth interviews were conducted with 10 HIV positive, West African women of black heritage living in London, UK. This group was of interest since it is the second largest group affected by HIV in the UK. Interviews were subjected to interpretative phenomenological analysis, an idiographic, experiential, qualitative approach. The paper details the women's negative experience of treatment. ART can be considered difficult and unrelenting and may be disconnected from the women's sense of health or illness. Participants' social context often exacerbated the difficulties. Some reported an improvement in their feelings about the medication over time. These findings point to some intrinsic and social motivators which could act as spurs to adherence. PMID:26767539

  4. Poor CD4 count is a predictor of untreated depression in human immunodeficiency virus-positive African-Americans

    PubMed Central

    Amanor-Boadu, Sasraku; Hipolito, MariaMananita S; Rai, Narayan; McLean, Charlee K; Flanagan, Kyla; Hamilton, Flora T; Oji, Valerie; Lambert, Sharon F; Le, Huynh Nhu; Kapetanovic, Suad; Nwulia, Evaristus A

    2016-01-01

    AIM: To determine if efforts to improve antiretroviral therapy (ART) adherence minimizes the negative impact of depression on human immunodeficiency virus (HIV) outcomes. METHODS: A cross-sectional study of a clinic-based cohort of 158 HIV seropositive (HIV+) African Americans screened for major depressive disorder (MDD) in 2012. CD4 T lymphocyte (CD4+) counts were obtained from these individuals. Self-report on adherence to ART was determined from questionnaire administered during clinic visits. The primary outcome measure was conditional odds of having a poorer CD4+ count (< 350 cells/mm3). Association between CD4+ count and antidepressant-treated or untreated MDD subjects was examined controlling for self-reported adherence and other potential confounders. RESULTS: Out of 147 individuals with available CD4+ T lymphocyte data, 31% hadCD4+ count < 350 cells/mm3 and 28% reported poor ART adherence. As expected the group with > 350 cells/mm3 CD4+ T lymphocyte endorsed significantly greater ART adherence compared to the group with < 350 cells/mm3 CD4+ T lymphocyte count (P < 0.004). Prevalence of MDD was 39.5% and 66% of individuals with MDD took antidepressants. Poor CD4+ T lymphocyte count was associated with poor ART adherence and MDD. Adjusting for ART adherence, age, sex and education, which were potential confounders, the association between MDD and poor CD4+ T lymphocyte remained significant only in the untreated MDD group. CONCLUSION: Therefore, CD4+ count could be a clinical marker of untreated depression in HIV+. Also, mental health care may be relevant to primary care of HIV+ patients. PMID:27014603

  5. Process Evaluation of the Project SHINE Intervention for African American Families: An Integrated Positive Parenting and Peer Monitoring Approach to Health Promotion.

    PubMed

    St George, Sara M; Wilson, Dawn K; McDaniel, Tyler; Alia, Kassandra A

    2016-07-01

    This study describes the process evaluation of Project SHINE, a randomized family-based health promotion intervention that integrated parenting and peer monitoring for improving sedentary behavior, physical activity, and diet in African American families. Adolescent-parent dyads (n = 89) were randomized to a 6-week behavioral, positive parenting, and peer monitoring skills intervention or a general health education comparison condition. Process evaluation included observational ratings of fidelity, attendance records, psychosocial measures, and qualitative interviews. Results indicated that the intervention was delivered with high fidelity based on facilitator adherence (>98% of content delivered) and competent use of theoretically based behavior change and positive parenting skills (100% of ratings >3 on a 1-4 scale). Although only 43% of peers attended the "bring a friend" session, overall attendance was high (4.39 ± 1.51 sessions) as was the retention rate (88%). Parents in the intervention condition reported significant improvements in communication related to adolescents' engagement in health behaviors both on their own and with peers. These findings were supported by qualitative themes related to improvements in family communication and connectedness. This study provides an innovative example of how future family-based health promotion trials can expand their process evaluation approaches by assessing theoretically relevant positive parenting variables as part of ongoing monitoring. PMID:27084025

  6. Emotion-Oriented Coping, Avoidance Coping, and Fear of Pain as Mediators of the Relationship between Positive Affect, Negative Affect, and Pain-Related Distress among African American and Caucasian College Women

    ERIC Educational Resources Information Center

    Lightsey, Owen Richard, Jr.; Wells, Anita G.; Wang, Mei-Chuan; Pietruszka, Todd; Ciftci, Ayse; Stancil, Brett

    2009-01-01

    The authors tested whether coping styles and fear of pain mediate the relationship between positive affect and negative affect on one hand and pain-related distress (PD) on the other. Among African American and Caucasian female college students, negative affect, fear of pain, and emotion-oriented coping together accounted for 34% of the variance…

  7. Suicide in Three East African Pastoralist Communities and the Role of Researcher Outsiders for Positive Transformation: A Case Study.

    PubMed

    Straight, Bilinda; Pike, Ivy; Hilton, Charles; Oesterle, Matthias

    2015-09-01

    We examine cultural understandings and practices surrounding suicide in Pokot, Samburu, and Turkana pastoralists in north-central Kenya--three geographically overlapping and mutually interacting pastoralist communities. We collected our data in the context of a study of poverty, violence, and distress. In all three communities, stigma associated with suicide circumscribed individual responses to the World Health Organization's Self-Report Questionnaire, which led to an ethnographic sub-study of suicide building upon our long-standing research in East Africa on distress, violence, and death. As is true for most of sub-Saharan Africa, reliable statistical data are non-existent for these communities. Thus, we deliberately avoid making assertions about generalizable statistical trends. Rather, we take the position that ethnographically nuanced studies like the one we offer here provide a necessary basis for the respectful collection of accurate quantitative data on this important and troubling practice. Moreover, our central point in this paper is that positive transformational work relating to suicide is most likely when researcher outsiders practice 'deep engagement' while respectfully restricting their role to (1) iterative, community-driven approaches that contextualize suicide; and (2) sharing contextualized analyses with other practitioners. We contend that situating suicide within a broader cultural framework that includes attitudes and practices surrounding other forms of death is essential to both aspects of anthropological-outsiders' role. PMID:25381581

  8. Association of Internalized and Social Network Level HIV Stigma With High-Risk Condomless Sex Among HIV-Positive African American Men.

    PubMed

    Wagner, Glenn J; Bogart, Laura M; Klein, David J; Green, Harold D; Mutchler, Matt G; McDavitt, Bryce; Hilliard, Charles

    2016-08-01

    We examined whether internalized HIV stigma and perceived HIV stigma from social network members (alters), including the most popular and most similar alter, predicted condomless intercourse with negative or unknown HIV status partners among 125 African American HIV-positive men. In a prospective, observational study, participants were administered surveys at baseline and months 6 and 12, with measures including sexual behavior, internalized HIV stigma, and an egocentric social network assessment that included several measures of perceived HIV stigma among alters. In longitudinal multivariable models comparing the relative predictive value of internalized stigma versus various measures of alter stigma, significant predictors of having had condomless intercourse included greater internalized HIV stigma (in all models), the perception that a popular (well-connected) alter or alter most like the participant agrees with an HIV stigma belief, and the interaction of network density with having any alter that agrees with a stigma belief. The interaction indicated that the protective effect of greater density (connectedness between alters) in terms of reduced risk behavior dissipated in the presence of perceived alter stigma. These findings call for interventions that help people living with HIV to cope with their diagnosis and reduce stigma, and inform the targets of social network-based and peer-driven HIV prevention interventions. PMID:26718361

  9. Substance use, mental illness, and familial conflict non-negotiation among HIV-positive African-Americans: latent class regression and a new syndemic framework.

    PubMed

    Robinson, Allysha C; Knowlton, Amy R; Gielen, Andrea C; Gallo, Joseph J

    2016-02-01

    We evaluated a synergistic epidemic (syndemic) of substance use, mental illness, and familial conflict non-negotiation among HIV-positive injection drug users (IDU). Baseline BEACON study data was utilized. Latent class analyses identified syndemic classes. These classes were regressed on sex, viral suppression, and acute care non-utilization. Females were hypothesized to have higher syndemic burden, and worse health outcomes than males. Nine percent of participants had high substance use/mental illness prevalence (Class 4); 23 % had moderate levels of all factors (Class 3); 25 % had high mental illness (Class 2); 43 % had moderate substance use/mental illness (Class 1; N = 331). Compared to Classes 1-3, Class 4 was mostly female (p < .05), less likely to achieve viral suppression, and more likely to utilize acute care (p < .05). Interventions should target African-American IDU females to improve their risk of negative medical outcomes. Findings support comprehensive syndemic approaches to HIV interventions, rather than singular treatment methods. PMID:26296521

  10. The process of adaptation of a community-level, evidence-based intervention for HIV-positive African American men who have sex with men in two cities.

    PubMed

    Robinson, Beatrice E; Galbraith, Jennifer S; Lund, Sharon M; Hamilton, Autumn R; Shankle, Michael D

    2012-06-01

    We describe the process of adapting a community-level, evidence-based behavioral intervention (EBI), Community PROMISE, for HIV-positive African American men who have sex with men (AAMSM). The Centers for Disease Control and Prevention (CDC) Map of the Adaptation Process (MAP) guided the adaptation process for this new target population by two community-based organizations (CBOs) working in partnership with two research organizations. We describe five steps of the MAP, assessment, selection, preparation, pilot, and implementation, and the use of qualitative interviews, field observations, and a cross-sectional survey. We recommend: (1) development of a centralized interactive website, listserv, or other resources where agencies adapting EBIs can share tools, materials, experiences, lessons learned, and best practices; (2) strengthening Funding Opportunity Announcements by funding incrementally in phases linked to the MAP; and (3) research should examine (a) whether EBIs adapted by CBOs remain efficacious and (b) the best "fit" between the cultural and climate characteristics of effective collaborations between community- and research-based organizations. PMID:22676461

  11. The tyrosinase-positive oculocutaneous albinism gene shows locus homogeneity on chromosome 15q11-q13 and evidence of multiple mutations in southern African negroids

    SciTech Connect

    Kedda, M.A.; Stevens, G.; Manga, P.; Viljoen, C.; Jenkins, T.; Ramsay, M. Univ. of Witwatersrand, Johannesburg )

    1994-06-01

    Tyrosinase-positive oculocutaneous albinism (ty-pos OCA) is an autosomal recessive disorder of the melanin pigmentary system. South African ty-pos OCA individuals occur with two distinct phenotypes, with or without darkly pigmented patches (ephelides, or dendritic freckles) on exposed areas of the skin. These phenotypes are concordant within families, suggesting that there may be more than one mutation at the ty-pos OCA locus. Linkage studies carried out in 41 families have shown linkage between markers in the Prader-Willi/Angelman syndrome (PWS/AS) region on chromosome 15q11-q13 and ty-pos OCA. Analysis showed no obligatory crossovers between the alleles at the D15S12 locus and ty-pos OCA, suggesting that the D15S12 locus is very close to or part of the disease locus, which is postulated to be the human homologue, P, of the mouse pink-eyed dilution gene, p. Unlike caucasoid [open quotes]ty-pos OCA[close quotes] individuals, negroid ty-pos OCA individuals do not show any evidence of locus heterogeneity. Studies of allelic association between the polymorphic alleles detected at the D15S12 locus and ephelus status suggest that there was a single major mutation giving rise to ty-pos OCA without ephelides. There may, however, be two major mutations causing ty-pos OCA with ephelides, one associated with D15S12 allele 1 and the other associated with D15S12 allele 2. The two loci, GABRA5 and D15S24, flanking D15S12, are both hypervariable, and many different haplotypes were observed with the alleles at the three loci on both ty-pos OCA-associated chromosomes and [open quotes]normal[close quotes] chromosomes. No haplotype showed statistically significant association with ty-pos OCA, and thus none could be used to predict the origins of the ty-pos OCA mutations. On the basis of the D15S12 results, there is evidence for multiple ty-pos OCA mutations in southern African negroids. 31 refs., 1 fig., 3 tabs.

  12. Socio-Economic Position and Type 2 Diabetes Risk Factors: Patterns in UK Children of South Asian, Black African-Caribbean and White European Origin

    PubMed Central

    Thomas, Claudia; Nightingale, Claire M.; Donin, Angela S.; Rudnicka, Alicja R.; Owen, Christopher G.; Sattar, Naveed; Cook, Derek G.; Whincup, Peter H.

    2012-01-01

    Background Socio-economic position (SEP) and ethnicity influence type 2 diabetes mellitus (T2DM) risk in adults. However, the influence of SEP on emerging T2DM risks in different ethnic groups and the contribution of SEP to ethnic differences in T2DM risk in young people have been little studied. We examined the relationships between SEP and T2DM risk factors in UK children of South Asian, black African-Caribbean and white European origin, using the official UK National Statistics Socio-economic Classification (NS-SEC) and assessed the extent to which NS-SEC explained ethnic differences in T2DM risk factors. Methods and Findings Cross-sectional school-based study of 4,804 UK children aged 9–10 years, including anthropometry and fasting blood analytes (response rates 70%, 68% and 58% for schools, individuals and blood measurements). Assessment of SEP was based on parental occupation defined using NS-SEC and ethnicity on parental self-report. Associations between NS-SEC and adiposity, insulin resistance (IR) and triglyceride differed between ethnic groups. In white Europeans, lower NS-SEC status was related to higher ponderal index (PI), fat mass index, IR and triglyceride (increases per NS-SEC decrement [95%CI] were 1.71% [0.75, 2.68], 4.32% [1.24, 7.48], 5.69% [2.01, 9.51] and 3.17% [0.96, 5.42], respectively). In black African-Caribbeans, lower NS-SEC was associated with lower PI (−1.12%; [−2.01, −0.21]), IR and triglyceride, while in South Asians there were no consistent associations between NS-SEC and T2DM risk factors. Adjustment for NS-SEC did not appear to explain ethnic differences in T2DM risk factors, which were particularly marked in high NS-SEC groups. Conclusions SEP is associated with T2DM risk factors in children but patterns of association differ by ethnic groups. Consequently, ethnic differences (which tend to be largest in affluent socio-economic groups) are not explained by NS-SEC. This suggests that strategies aimed at reducing social

  13. Tyrosinase-positive oculocutaneous albinism in Southern African blacks: P gene-associated haplotypes suggest a major mutation in the 5{prime} region of the gene

    SciTech Connect

    Ramsay, M.; Stevens, G.; Beukering, J. van

    1994-09-01

    Tyrosinase-positive oculocutaneous albinism (ty-pos OCA) occurs with a prevalence of 1 in 3900 among Southern African (SA) blacks. The major contributors to morbidity and mortality are skin cancer and decreased visual acuity. Two distinct phenotypes occur, namely individuals with ephelides (darkly pigmented patches) and those without. There is complete concordance with regard to ephelus status among siblings. The disorder is linked to markers on chromosome 15q11.2-q12, and no obligatory cross-overs were observed with polymophic markers at the human homolog, P, of the mouse pink eyed dilute gene, p. Contrary to what has been shown for Caucasoid ty-pos OCA, this condition shows locus homogeneity among SA blacks. The P gene is an excellent candidate for ty-pos OCA and mutations in this gene will confirm its role in causing the common form of albinism in SA. Numerous P gene mutations have been described in other populations. In an attempt to detect mutations, the P gene cDNA was used to search for structural rearrangements or polymorphisms. Six polymorphisms (plR10/Scal, 912/Xbal, 912/HincII, 912/TaqI, 1412/TaqI [two systems] and 1412/HindIII) were detected with subclones of the P cDNA and haplotypes were determined in each family. None were clearly associated with an albinism-related rearrangement. However, strong linkage disequilibrium was observed with alleles at loci toward the 5{prime} region of the gene ({triangle}=0.65, 0.57 and 0.80 for the three polymorphisms detected with the 912 subclone), suggesting a major ty-pos OCA mutation in this region. Haplotype analysis provides evidence for a major mutation associated with the same haplotype in individuals with ephelides (8/12 OCA chromosomes) and those without ephelides (24:30). The presence of other ty-pos OCA associated haplotypes indicates several other less common mutations.

  14. Improving the Attendance Rate for African American Male Students in an After School Reading Program through Parental Involvement, Positive Male Role Models, and Tutorial Instruction.

    ERIC Educational Resources Information Center

    Tanksley, Mary Dennard

    This practicum was designed to improve the attendance rate for African American male students in the After School Reading Is Fundamental (RIF) program. The attendance rate for male students was far below that of female students. The following strategies to increase male participation in the reading program were developed: local businesses and…

  15. Family Involvement with African-American Youth during the Pre-College Years: From a "Psychology of Oppression" to a "Positive Black Psychology"

    ERIC Educational Resources Information Center

    Jones, Clara B.; Palmer, Julie K.

    2004-01-01

    This paper addresses ways ways in which African-American families can influence their children's development, usually with guidance from school or other community agents. We discuss the importance of "discipline styles" for effective parenting and emphasize an approach to family involvement in child development utilizing a child's strengths. We…

  16. RELATIONAL SCHEMAS, HOSTILE ROMANTIC RELATIONSHIPS, AND BELIEFS ABOUT MARRIAGE AMONG YOUNG AFRICAN AMERICAN ADULTS

    PubMed Central

    Simons, Ronald L.; Simons, Leslie Gordon; Lei, Man Kit; Landor, Antoinette

    2011-01-01

    The present study tests a developmental model designed to explain the romantic relationship difficulties and reluctance to marry often reported for African Americans. Using longitudinal data from a sample of approximately 400 African American young adults, we examine the manner in which race-related adverse experiences during late childhood and early adolescence give rise to the cynical view of romantic partners and marriage held by many young African Americans. Our results indicate that adverse circumstances disproportionately suffered by African American youth (viz., harsh parenting, family instability, discrimination, criminal victimization, and financial hardship) promote distrustful relational schemas that lead to troubled dating relationships, and that these negative relationship experiences, in turn, encourage a less positive view of marriage. PMID:22328799

  17. [Simultaneous association of tubercular meningitis and cryptococcal meningitis in an African with human immunodeficiency virus HIV positive serology. University Hospital Center of Bujumbura,Burundi].

    PubMed

    Niyongabo, T; Aubry, P

    1992-01-01

    The authors report a connection between a meningitis tuberculosis and a meningoencephalitis with cryptococcus in the case of an african VIH+. The diagnostic of a meningitis tuberculosis was retained on an indirect arguments, this of meningoencephalitis of direct arguments (antigen cryptococcus, cultivation on Sabouraud environment). The pulmonary tuberculosis and/or extrapulmonary tuberculosis is current in Central Africa during HIV infection, as well as the crytococcosis during AIDS. But, any observation on neuromeningitis strike of those two infections have been reported up to now. PMID:1406216

  18. A longitudinal study of the changes in body fat and metabolic parameters in a South African population of HIV-positive patients receiving an antiretroviral therapeutic regimen containing stavudine.

    PubMed

    George, Jaya A; Venter, Willem D F; Van Deventer, Hendrick E; Crowther, Nigel J

    2009-08-01

    The aim of this study was to determine the patterns of change in body fat and metabolic parameters in a South African cohort on a first line ART regimen containing stavudine. Fasting lipogram, blood glucose and insulin levels, CD4 cell count, viral load, BMI, waist-to-hip ratio (WHR), and skinfold thickness at the triceps, scapula, and iliac crest were measured before starting ART in 42 (27 female) subjects. Repeat measurements were performed at four monthly intervals for 2 years. Lipodystrophy was diagnosed using patient perception and assessment by a physician. At baseline, subjects who went on to develop lipodystrophy (LD group) were fatter and had higher skinfold thickness at all three sites and higher insulin levels than subjects who never developed lipodystrophy (NLD group). The WHR increased to a greater extent while hip circumference and tricep skinfolds fell more significantly in the LD than NLD group. Triglyceride and cholesterol levels increased significantly in both groups while lactate and glucose levels increased more and insulin levels increased less in the LD than the NLD group. Neither viral load nor CD4 count differed between the groups during the study. Viral load correlated positively with insulin levels at baseline. Thus, lipodystrophy in the South African population is characterized by a higher BMI before initiation of ART and lipoatrophy of the arms and hips, lipohypertrophy of the waist, and increased lactate production. When compared to the NLD group, the LD subjects display attenuated insulin secretory output in response to a higher weight gain. PMID:19619010

  19. Narcolepsy in African Americans

    PubMed Central

    Kawai, Makoto; O'Hara, Ruth; Einen, Mali; Lin, Ling; Mignot, Emmanuel

    2015-01-01

    Study Objectives: Although narcolepsy affects 0.02–0.05% of individuals in various ethnic groups, clinical presentation in different ethnicities has never been fully characterized. Our goal was to study phenotypic expression across ethnicities in the United States. Design/Setting: Cases of narcolepsy from 1992 to 2013 were identified from searches of the Stanford Center for Narcolepsy Research database. International Classification of Sleep Disorders, Third Edition diagnosis criteria for type 1 and type 2 narcolepsy were used for inclusion, but subjects were separated as with and without cataplexy for the purpose of data presentation. Information extracted included demographics, ethnicity and clinical data, HLA-DQB1*06:02, polysomnography (PSG), multiple sleep latency test (MSLT) data, and cerebrospinal fluid (CSF) hypocretin-1 level. Patients: 182 African-Americans, 839 Caucasians, 35 Asians, and 41 Latinos with narcolepsy. Results: Sex ratio, PSG, and MSLT findings did not differ across ethnicities. Epworth Sleepiness Scale (ESS) score was higher and age of onset of sleepiness earlier in African Americans compared with other ethnicities. HLA-DQB1*06:02 positivity was higher in African Americans (91.0%) versus others (76.6% in Caucasians, 80.0% in Asians, and 65.0% in Latinos). CSF hypocretin-1 level, obtained in 222 patients, was more frequently low (≤ 110 pg/ml) in African Americans (93.9%) versus Caucasians (61.5%), Asians (85.7%) and Latinos (75.0%). In subjects with low CSF hypocretin-1, African Americans (28.3%) were 4.5 fold more likely to be without cataplexy when compared with Caucasians (8.1%). Conclusions: Narcolepsy in African Americans is characterized by earlier symptom onset, higher Epworth Sleepiness Scale score, higher HLA-DQB1*06:02 positivity, and low cerebrospinal fluid hypocretin-1 level in the absence of cataplexy. In African Americans, more subjects without cataplexy have type 1 narcolepsy. Citation: Kawai M, O'Hara R, Einen M, Lin L

  20. The Offshore East African Rift System

    NASA Astrophysics Data System (ADS)

    Franke, D.; Klimke, J.; Jokat, W.; Stollhofen, H.; Mahanjane, S.

    2014-12-01

    Numerous studies have addressed various aspects of the East African Rift system but surprisingly few on the offshore continuation of the south-eastern branch of the rift into the Mozambique Channel. The most prominent article has been published almost 30 years ago by Mougenot et al. (1986) and is based on vintage seismic data. Several studies investigating earthquakes and plate motions from GPS measurements reveal recent deformation along the offshore branch of the East African Rift system. Slip vectors from earthquakes data in Mozambique's offshore basins show a consistent NE direction. Fault plane solutions reveal ~ E-W extensional failure with focal depth clustering around 19 km and 40 km, respectively. Here, we present new evidence for neotectonic deformation derived from modern seismic reflection data and supported by additional geophysical data. The modern rift system obviously reactivates structures from the disintegration of eastern Gondwana. During the Jurassic/Cretaceous opening of the Somali and Mozambique Basins, Madagascar moved southwards along a major shear zone, to its present position. Since the Miocene, parts of the shear zone became reactivated and structurally overprinted by the East African rift system. The Kerimbas Graben offshore northern Mozambique is the most prominent manifestation of recent extensional deformation. Bathymetry data shows that it deepens northwards, with approximately 700 m downthrown on the eastern shoulder. The graben can be subdivided into four subbasins by crosscutting structural lineaments with a NW-SE trend. Together with the N-S striking graben-bounding faults, this resembles a conjugate fault system. In seismic reflection data normal faulting is distinct not only at the earthquake epicenters. The faults cut through the sedimentary successions and typically reach the seafloor, indicating ongoing recent deformation. Reference: Mougenot, D., Recq, M., Virlogeux, P., and Lepvrier, C., 1986, Seaward extension of the East

  1. Optimizing the Zeldovich approximation

    NASA Technical Reports Server (NTRS)

    Melott, Adrian L.; Pellman, Todd F.; Shandarin, Sergei F.

    1994-01-01

    We have recently learned that the Zeldovich approximation can be successfully used for a far wider range of gravitational instability scenarios than formerly proposed; we study here how to extend this range. In previous work (Coles, Melott and Shandarin 1993, hereafter CMS) we studied the accuracy of several analytic approximations to gravitational clustering in the mildly nonlinear regime. We found that what we called the 'truncated Zeldovich approximation' (TZA) was better than any other (except in one case the ordinary Zeldovich approximation) over a wide range from linear to mildly nonlinear (sigma approximately 3) regimes. TZA was specified by setting Fourier amplitudes equal to zero for all wavenumbers greater than k(sub nl), where k(sub nl) marks the transition to the nonlinear regime. Here, we study the cross correlation of generalized TZA with a group of n-body simulations for three shapes of window function: sharp k-truncation (as in CMS), a tophat in coordinate space, or a Gaussian. We also study the variation in the crosscorrelation as a function of initial truncation scale within each type. We find that k-truncation, which was so much better than other things tried in CMS, is the worst of these three window shapes. We find that a Gaussian window e(exp(-k(exp 2)/2k(exp 2, sub G))) applied to the initial Fourier amplitudes is the best choice. It produces a greatly improved crosscorrelation in those cases which most needed improvement, e.g. those with more small-scale power in the initial conditions. The optimum choice of kG for the Gaussian window is (a somewhat spectrum-dependent) 1 to 1.5 times k(sub nl). Although all three windows produce similar power spectra and density distribution functions after application of the Zeldovich approximation, the agreement of the phases of the Fourier components with the n-body simulation is better for the Gaussian window. We therefore ascribe the success of the best-choice Gaussian window to its superior treatment

  2. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

    No single traditional discipline can adequately supply answers to the many unresolved questions in African art history. Because of the aesthetic, cultural, historical, and, not infrequently, political biases, already built into the conception and development of Western art history, the discipline of art history as defined and practiced in the West…

  3. Larger genetic differences within africans than between Africans and Eurasians.

    PubMed Central

    Yu, Ning; Chen, Feng-Chi; Ota, Satoshi; Jorde, Lynn B; Pamilo, Pekka; Patthy, Laszlo; Ramsay, Michele; Jenkins, Trefor; Shyue, Song-Kun; Li, Wen-Hsiung

    2002-01-01

    The worldwide pattern of single nucleotide polymorphism (SNP) variation is of great interest to human geneticists, population geneticists, and evolutionists, but remains incompletely understood. We studied the pattern in noncoding regions, because they are less affected by natural selection than are coding regions. Thus, it can reflect better the history of human evolution and can serve as a baseline for understanding the maintenance of SNPs in human populations. We sequenced 50 noncoding DNA segments each approximately 500 bp long in 10 Africans, 10 Europeans, and 10 Asians. An analysis of the data suggests that the sampling scheme is adequate for our purpose. The average nucleotide diversity (pi) for the 50 segments is only 0.061% +/- 0.010% among Asians and 0.064% +/- 0.011% among Europeans but almost twice as high (0.115% +/- 0.016%) among Africans. The African diversity estimate is even higher than that between Africans and Eurasians (0.096% +/- 0.012%). From available data for noncoding autosomal regions (total length = 47,038 bp) and X-linked regions (47,421 bp), we estimated the pi-values for autosomal regions to be 0.105, 0.070, 0.069, and 0.097% for Africans, Asians, Europeans, and between Africans and Eurasians, and the corresponding values for X-linked regions to be 0.088, 0.042, 0.053, and 0.082%. Thus, Africans differ from one another slightly more than from Eurasians, and the genetic diversity in Eurasians is largely a subset of that in Africans, supporting the out of Africa model of human evolution. Clearly, one must specify the geographic origins of the individuals sampled when studying pi or SNP density. PMID:12019240

  4. CYP2B6*6 and CYP2B6*18 Predict Long-Term Efavirenz Exposure Measured in Hair Samples in HIV-Positive South African Women.

    PubMed

    Röhrich, Carola R; Drögemöller, Britt I; Ikediobi, Ogechi; van der Merwe, Lize; Grobbelaar, Nelis; Wright, Galen E B; McGregor, Nathaniel; Warnich, Louise

    2016-06-01

    Long-term exposure to efavirenz (EFV) measured in hair samples may predict response to antiretroviral treatment (ART). Polymorphisms in CYP2B6 are known to alter EFV levels. The aim of this study was to assess the relationship between CYP2B6 genotype, EFV levels measured in hair, and virological outcomes on ART in a real-world setting. We measured EFV levels in hair from HIV-positive South African females who had been receiving EFV-based treatment for at least 3 months from the South African Black (SAB) (n = 81) and Cape Mixed Ancestry (CMA) (n = 53) populations. Common genetic variation in CYP2B6 was determined in 15 individuals from each population using bidirectional Sanger sequencing. Prioritized variants (n = 16) were subsequently genotyped in the entire patient cohort (n = 134). The predictive value of EFV levels in hair and selected variants in CYP2B6 on virological treatment outcomes was assessed. Previously described alleles (CYP2B6*2, CYP2B6*5, CYP2B6*6, CYP2B6*17, and CYP2B6*18), as well as two novel alleles (CYP2B6*31 and CYP2B6*32), were detected in this study. Compared to noncarriers, individuals homozygous for CYP2B6*6 had ∼109% increased EFV levels in hair (p = .016) and CYP2B6*18 heterozygotes demonstrated 82% higher EFV hair levels (p = .0006). This study confirmed that alleles affecting CYP2B6 metabolism and subsequent EFV exposure are present at significant frequencies in both the SAB and CMA populations. Furthermore, this study demonstrated that the use of hair samples for testing EFV concentrations may be a useful tool in determining long-term drug exposure in resource-limited countries. PMID:26655325

  5. African American Women in Higher Education

    ERIC Educational Resources Information Center

    Zamani, Eboni M.

    2003-01-01

    African American women hold a unique position as members of two groups that have been treated in a peripheral manner by postsecondary education (Moses, 1989). Membership in both marginalized groups often makes African American women invisible in colleges and universities. Given the complex intersection of race and gender, more attention should be…

  6. An Exploration of African American Students' Attitudes toward Online Learning

    ERIC Educational Resources Information Center

    Okwumabua, Theresa M.; Walker, Kristin M.; Hu, Xiangen; Watson, Andrea

    2011-01-01

    The current work presents exploratory research findings concerning African American students' attitudes toward online learning. The Online Tutoring Attitudes Scale (OTAS; Graff, 2003) was administered to 124 African American students in a positive youth development program. Findings suggest that African American students' attitudes toward…

  7. Perceived Attractiveness, Facial Features, and African Self-Consciousness.

    ERIC Educational Resources Information Center

    Chambers, John W., Jr.; And Others

    1994-01-01

    Investigated relationships between perceived attractiveness, facial features, and African self-consciousness (ASC) among 149 African American college students. As predicted, high ASC subjects used more positive adjectives in descriptions of strong African facial features than did medium or low ASC subjects. Results are discussed in the context of…

  8. Gender Differences in African American Attitudes toward Gay Males.

    ERIC Educational Resources Information Center

    Battle, Juan; Lemelle, Anthony J., Jr.

    2002-01-01

    Used data from the 1993 National Black Politics Study to examine the way gender worked in explaining African American attitudes toward gay men. Results indicated that African American females expressed more positive attitudes toward homosexual men than did African American males, and of the variables examined (including age, church attendance,…

  9. Obesity and African Americans

    MedlinePlus

    ... Data > Minority Population Profiles > Black/African American > Obesity Obesity and African Americans African American women have the ... ss6304.pdf [PDF | 3.38MB] HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...

  10. Health-Related Quality of Life Dynamics of HIV-positive South African Women up to ART Initiation: Evidence from the CAPRISA 002 Acute Infection Cohort Study

    PubMed Central

    Tomita, Andrew; Garrett, Nigel; Werner, Lise; Burns, Jonathan K.; Mpanza, Lindiwe; Mlisana, Koleka; van Loggerenberg, Francois; Karim, Salim S. Abdool

    2014-01-01

    Few studies have investigated the long-term dynamics in health-related quality of life (HRQoL) among HIV-positive persons from acute infection. From 2004, 160 women were enrolled into the CAPRISA 002 Acute Infection study at two sites in the province of KwaZulu-Natal and underwent 3–6 monthly HRQoL assessments using the functional assessment of HIV infection (FAHI) instrument. Overall and 5 sub-scale FAHI scores [physical well-being (PWB), emotional well-being (EWB), functional and global well-being (FGWB), social well-being (SWB) and cognitive functioning (CF)] were calculated up to antiretroviral therapy (ART) initiation and scores at enrollment were compared to the acute, early and established infection phases. Mixed-effects regression models adjusting for behavioral and clinical factors were applied to assess HRQoL trends and the proportion of women meeting minimally important differences was calculated. Our analyses revealed that overall/sub-scale scores improved over time, except from PWB and CF. A higher educational status, contraceptive use and a higher BMI were the strongest predictors of higher overall/sub-scale FAHI scores. CD4 count and HIV viral load were strongly associated with PWB and CF, but not overall FAHI and other sub-scales. Women newly diagnosed with acute HIV infection face profound HRQoL challenges. While early ART delivery may be important for PWB and CF, factors such as education, contraception provision and good nutritional status should be promoted to maximize HRQoL in HIV positive individuals. PMID:24368630

  11. Health-related quality of life dynamics of HIV-positive South African women up to ART initiation: evidence from the CAPRISA 002 acute infection cohort study.

    PubMed

    Tomita, Andrew; Garrett, Nigel; Werner, Lise; Burns, Jonathan K; Mpanza, Lindiwe; Mlisana, Koleka; van Loggerenberg, Francois; Abdool Karim, Salim S

    2014-06-01

    Few studies have investigated the long-term dynamics in health-related quality of life (HRQoL) among HIV-positive persons from acute infection. From 2004, 160 women were enrolled into the CAPRISA 002 Acute Infection study at two sites in the province of KwaZulu-Natal and underwent 3-6 monthly HRQoL assessments using the functional assessment of HIV infection (FAHI) instrument. Overall and 5 sub-scale FAHI scores [physical well-being (PWB), emotional well-being (EWB), functional and global well-being (FGWB), social well-being (SWB) and cognitive functioning (CF)] were calculated up to antiretroviral therapy (ART) initiation and scores at enrollment were compared to the acute, early and established infection phases. Mixed-effects regression models adjusting for behavioral and clinical factors were applied to assess HRQoL trends and the proportion of women meeting minimally important differences was calculated. Our analyses revealed that overall/sub-scale scores improved over time, except from PWB and CF. A higher educational status, contraceptive use and a higher BMI were the strongest predictors of higher overall/sub-scale FAHI scores. CD4 count and HIV viral load were strongly associated with PWB and CF, but not overall FAHI and other sub-scales. Women newly diagnosed with acute HIV infection face profound HRQoL challenges. While early ART delivery may be important for PWB and CF, factors such as education, contraception provision and good nutritional status should be promoted to maximize HRQoL in HIV positive individuals. PMID:24368630

  12. South African-ness Among Adolescents: The Emergence of a Collective Identity within the Birth to Twenty Cohort Study

    PubMed Central

    Norris, Shane A; Roeser, Robert W.; Richter, Linda M; Lewin, Nina; Ginsburg, Carren; Fleetwood, Stella A; Taole, Elizabeth; van der Wolf, Kees

    2009-01-01

    We assessed the emergence of a South African identity among Black, Colored (mixed ancestral origin), White (predominantly English speaking), and Indian adolescents participating in a birth cohort study called “Birth to Twenty” in Johannesburg, South Africa. We examined young people's certainty of their self-categorization as South African, the centrality of their personal, racial and linguistic, and South African identities in their self-definition, and their perceptions of South African life and society today. These results reflect a historical opportunity for full citizenship and national enfranchisement that the end of Apartheid heralded for Black and Colored individuals. Black and Colored youth tend to be more certain about their South African-ness, have a more collective identity, and have a more positive perception around South Africa. In contrast, White and Indian youth are less certain about their South African-ness, have a more individualistic identity, and have a less positive perception about South Africa today. PMID:19461896

  13. Evaluation of decision rules for identifying low bone density in postmenopausal African-American women.

    PubMed Central

    Wallace, Lorraine Silver; Ballard, Joyce E.; Holiday, David; Turner, Lori W.; Keenum, Amy J.; Pearman, Cynthia M.

    2004-01-01

    OBJECTIVE: While African-American women tend to have greater bone mineral density (BMD) than caucasian women, they are still at risk of developing osteoporosis later in life. Clinical decision rules (i.e., algorithms) have been developed to assist clinicians identify women at greatest risk of low BMD. However, such tools have only been validated in caucasian and Asian populations. Accordingly, the objective of this study was to compare the performance of five clinical decision rules in identifying postmenopausal African-American women at greatest risk for low femoral BMD. METHODOLOGY: One hundred-seventy-four (n=174) postmenopausal African-American women completed a valid and reliable oral questionnaire to assess lifestyle characteristics, and completed height and weight measures. BMD at the femoral neck was measured via dual energy x-ray absorptiometry (DXA). We calculated sensitivity, specificity, positive predictive value, and negative predictive value for identifying African-American women with low BMD (T-Score < or = -2.0 SD) using five clinical decision rules: Age, Body Size, No Estrogen (ABONE), Osteoporosis Risk Assessment Instrument (ORAI), Osteoporosis Self-Assessment Tool (OST), Simple Calculated Osteoporosis Risk Estimation (SCORE), and body weight less than 70 kg. RESULTS: Approximately 30% of African-American women had low BMD, half of whom had osteoporosis (BMD T-Score < or = -2.5 SD). Sensitivity for identifying women with a low BMD (T-Score < or = -2.0 SD) ranged from 65.57-83.61%, while specificity ranged from 53.85-78.85%. Positive predictive values ranged from 80.95-87.91%, while negative predictive values ranged from 48.44-58.33%. CONCLUSION: Our data suggest that the clinical decision rules analyzed in this study have some usefulness for identifying postmenopausal African-American women with low BMD. However, there is a need to establish cut-points for these clinical decision rules in a larger, more diverse sample of African-American women

  14. Is human immunodeficiency virus (HIV) stage an independent risk factor for altering the periodontal status of HIV-positive patients? A South African study

    PubMed Central

    2013-01-01

    Background The immunosuppresion in HIV patients makes them highly susceptible to microbial infections. The aim of the study was to establish whether HIV stage (as depicted by CD4+ T lymphocyte counts) could independently be associated with periodontal status (as revealed by the measurement of clinical indices). Methods One hundred and twenty HIV-infected patients attending an infectious diseases clinic in the Western Cape, South Africa were included in the study. The periodontal clinical indices such as plaque index, gingival index, pocket probing depth and clinical attachment levels were measured on the mesial aspect of the six Ramfjord teeth. The CD4 + T cell counts were taken from the patients’ medical records and patients’ HIV stage determined and grouped according to their CD4+ T cell counts into A (<200 cells /mm3), B (200–500 cells /mm3) and C (>500 cells /mm3). Results The mean age of 120 HIV-positive patients was 33.25 years and the mean CD4 + T cell count was 293.43 cells/mm3. The probing depth and clinical attachment loss were found to be significantly associated with the total CD4 + T cell counts but not with HIV stage. Significant correlations were found between age and all clinical indices except for clinical attachment loss. No correlation was found between age and HIV stage of the patients. The use of antiretroviral therapy was significantly associated with probing depth and clinical attachment loss, but not with plaque nor gingival index. Significant associations were observed between smoking and all of the clinical indices except for the gingival index. A significant association was observed between the use of interdental aids and all the clinical indices except for probing depth, while brushing was significantly associated with plaque index only. CD4 + T cell counts were significantly associated with brushing frequency (p = 0.0190) and the use of interdental aids (p = 0.0170). Conclusion The findings of this study

  15. CD4 trajectory adjusting for dropout among HIV-positive patients receiving combination antiretroviral therapy in an East African HIV care centre

    PubMed Central

    Kiragga, Agnes N; Lok, Judith J; Musick, Beverly S; Bosch, Ronald J; Mwangi, Ann; Wools-Kaloustian, Kara K; Yiannoutsos, Constantin T

    2014-01-01

    Objective Estimates of CD4 response to antiretroviral therapy (ART) obtained by averaging data from patients in care, overestimate population CD4 response and treatment program effectiveness because they do not consider data from patients who are deceased or not in care. We use mathematical methods to assess and adjust for this bias based on patient characteristics. Design We examined data from 25,261 HIV-positive patients from the East Africa IeDEA Consortium. Methods We used inverse probability of censoring weighting (IPCW) to represent patients not in care by patients in care with similar characteristics. We address two questions: What would the median CD4 be “had everyone starting ART remained on observation?” and “were everyone starting ART maintained on treatment?” Results Routine CD4 count estimates were higher than adjusted estimates even under the best-case scenario of maintaining all patients on treatment. Two years after starting ART, differences between estimates diverged from 30 cells/µL, assuming similar mortality and treatment access among dropouts as patients in care, to over 100 cells/µL assuming 20% lower survival and 50% lower treatment access among dropouts. When considering only patients in care, the proportion of patients with CD4 above 350 cells/µL was 50% adjusted to below 30% when accounting for patients not in care. One-year mortality diverged 6–14% from the naïve estimates depending on assumptions about access to care among lost patients. Conclusions Ignoring mortality and loss to care results in over-estimation of ART response for patients starting treatment and exaggerates the efficacy of treatment programs administering it. PMID:25131801

  16. Approximate flavor symmetries

    SciTech Connect

    Rasin, A.

    1994-04-01

    We discuss the idea of approximate flavor symmetries. Relations between approximate flavor symmetries and natural flavor conservation and democracy models is explored. Implications for neutrino physics are also discussed.

  17. New data on African health professionals abroad

    PubMed Central

    Clemens, Michael A; Pettersson, Gunilla

    2008-01-01

    Background The migration of doctors and nurses from Africa to developed countries has raised fears of an African medical brain drain. But empirical research on the causes and effects of the phenomenon has been hampered by a lack of systematic data on the extent of African health workers' international movements. Methods We use destination-country census data to estimate the number of African-born doctors and professional nurses working abroad in a developed country circa 2000, and compare this to the stocks of these workers in each country of origin. Results Approximately 65,000 African-born physicians and 70,000 African-born professional nurses were working overseas in a developed country in the year 2000. This represents about one fifth of African-born physicians in the world, and about one tenth of African-born professional nurses. The fraction of health professionals abroad varies enormously across African countries, from 1% to over 70% according to the occupation and country. Conclusion These numbers are the first standardized, systematic, occupation-specific measure of skilled professionals working in developed countries and born in a large number of developing countries. PMID:18186916

  18. Africans in America.

    ERIC Educational Resources Information Center

    Hart, Ayanna; Spangler, Earl

    This book introduces African-American history and culture to children. The first Africans in America came from many different regions and cultures, but became united in this country by being black, African, and slaves. Once in America, Africans began a long struggle for freedom which still continues. Slavery, the Civil War, emancipation, and the…

  19. African Outreach Workshop 1974.

    ERIC Educational Resources Information Center

    Schmidt, Nancy J.

    This report discusses the 1974 African Outreach Workshop planned and coordinated by the African Studies Program at the University of Illinois at Urbana-Champaign. Its major aim was to assist teachers in developing curriculum units on African using materials available in their local community. A second aim was for the African Studies Program to…

  20. The African Pediatric Fellowship Program: Training in Africa for Africans.

    PubMed

    Wilmshurst, Jo M; Morrow, Brenda; du Preez, Avril; Githanga, David; Kennedy, Neil; Zar, Heather J

    2016-01-01

    Africa has a significant burden of childhood disease, with relatively few skilled health care professionals. The African Paediatric Fellowship Programme was developed by the Department of Pediatrics and Child Health at the University of Cape Town to provide relevant training for African child health professionals, by Africans, within Africa. Trainees identified by partner academic institutions spend 6 months to 2 years training in the Department of Pediatrics and allied disciplines. They then return to their home institution to build practice, training, research, and advocacy. From 2008 to 2015, 73 physicians have completed or are completing training in general pediatrics or a pediatric subspecialty. At 1 year posttraining, 98% to 100% are practicing back in their home institution. The impact of the returning fellows is evident from their practice interventions, research collaborations, and positions as stakeholders who can change health care policies. Thirty-three centers in 13 African countries are partners with the program, and the program template is now followed by other partner sites in Africa. Increasing and retaining the skills pool of African child health specialists is building a network of motivated, highly skilled clinicians who are equipped to advance child health in Africa. PMID:26659458

  1. HLA disease association and protection in HIV infection among African Americans and Caucasians.

    PubMed

    Cruse, J M; Brackin, M N; Lewis, R E; Meeks, W; Nolan, R; Brackin, B

    1991-01-01

    In a previous investigation, we demonstrated an increased progression of overt AIDS in the African American population compared to the Caucasian population as reflected by the significantly lower absolute number of CD4+ lymphocytes detected in the African American population in an earlier study. The present study elucidates some of the possible genetic factors which may contribute to disease association or protection against HIV infection. The HLA phenotypes expressed as A, B, C, DR and DQw antigens were revealed by the Amos-modified typing procedure. NIH scoring was utilized to designate positive cells taking up trypan blue. A test of proportion equivalent to the chi 2 approximation was used to compare the disease population (n = 62; 38 African Americans, 24 Caucasians) to race-matched normal heterosexual local controls (323 African Americans, 412 Caucasians). Significant p values were corrected for the number of HLA antigens tested. HLA markers associated with possible protection from infection for African Americans were Cw4 and DRw6, whereas Caucasians expressed none. Disease association markers present in the African American population were A31, B35, Cw6, Cw7, DR5, DR6, DRw11, DRw12, DQw6 and DQw7, whereas in the Caucasian population A28, Aw66, Aw48, Bw65, Bw70, Cw7, DRw10, DRw12, DQw6 and DQw7 were demonstrated. The highest phenotypic frequency for a disease association marker in the study was for HLA-DR5 (62.9%) in the HIV-infected African American population without Kaposi's sarcoma compared to a frequency of 28.9% for the regional control group (p = 0.0012). We conclude that genetic factors do have a role in HIV infection since only 50-60% of those exposed to the AIDS virus will become infected. PMID:1910527

  2. African oil plays

    SciTech Connect

    Clifford, A.J. )

    1989-09-01

    The vast continent of Africa hosts over eight sedimentary basins, covering approximately half its total area. Of these basins, only 82% have entered a mature exploration phase, 9% have had little or no exploration at all. Since oil was first discovered in Africa during the mid-1950s, old play concepts continue to bear fruit, for example in Egypt and Nigeria, while new play concepts promise to become more important, such as in Algeria, Angola, Chad, Egypt, Gabon, and Sudan. The most exciting developments of recent years in African oil exploration are: (1) the Gamba/Dentale play, onshore Gabon; (2) the Pinda play, offshore Angola; (3) the Lucula/Toca play, offshore Cabinda; (4) the Metlaoui play, offshore Libya/Tunisia; (5) the mid-Cretaceous sand play, Chad/Sudan; and (6) the TAG-I/F6 play, onshore Algeria. Examples of these plays are illustrated along with some of the more traditional oil plays. Where are the future oil plays likely to develop No doubt, the Saharan basins of Algeria and Libya will feature strongly, also the presalt of Equatorial West Africa, the Central African Rift System and, more speculatively, offshore Ethiopia and Namibia, and onshore Madagascar, Mozambique, and Tanzania.

  3. Breakfast habits of adolescents in for South African populations.

    PubMed

    Walker, A R; Walker, B F; Jones, J; Ncongwane, J

    1982-10-01

    Breakfast habits by using questionnaires, were established in a total of 4717 South African pupils of 16 to 18 yr. In the groups of rural and urban Black, Indian, European-African-Malay, and white pupils studied, respective proportions who had no solid breakfast (both sexes combined) were approximately 21, 19, 13, 13, and 14%. Proportions who had only porridge or bread (or toast) plus drink were 77, 73, 61, 71, and 56%. Such breakfast provided ranges of means of 223 to 345 kcal, 9 to 14 g protein, 7 to 18 g fat, 51 to 185 mg calcium, and 3.2 to 5.1 mg iron. Proportions who had a cooked breakfast (including egg, meat, fish), eaten with or without a cereal food, were 1, 4, 17, 8, and 29%. Such meals contributed means of 495 to 704 kcal, 11 to 26 g protein, 24 to 39 g fat, 110 to 225 mg calcium, and 3.9 to 5.5 mg iron. In the South African groups studied, the issue of breakfast or no breakfast had no clear-cut bearing on weight, height, class position, or frequency of absence from school. The degree by which, in a given community, nutrition in general and breakfast in particular, regulates health and/or academic performance, needs proper research in prospective studies. PMID:7124666

  4. One sign ion mobile approximation

    NASA Astrophysics Data System (ADS)

    Barbero, G.

    2011-12-01

    The electrical response of an electrolytic cell to an external excitation is discussed in the simple case where only one group of positive and negative ions is present. The particular case where the diffusion coefficients of the negative ions, Dm, is very small with respect to that of the positive ions, Dp, is considered. In this framework, it is discussed under what conditions the one mobile approximation, in which the negative ions are assumed fixed, works well. The analysis is performed by assuming that the external excitation is sinusoidal with circular frequency ω, as that used in the impedance spectroscopy technique. In this framework, we show that there exists a circular frequency, ω*, such that for ω > ω*, the one mobile ion approximation works well. We also show that for Dm ≪ Dp, ω* is independent of Dm.

  5. Approximate spatial reasoning

    NASA Technical Reports Server (NTRS)

    Dutta, Soumitra

    1988-01-01

    A model for approximate spatial reasoning using fuzzy logic to represent the uncertainty in the environment is presented. Algorithms are developed which can be used to reason about spatial information expressed in the form of approximate linguistic descriptions similar to the kind of spatial information processed by humans. Particular attention is given to static spatial reasoning.

  6. Nutritional support of malnourished lactose intolerant African patients.

    PubMed Central

    O'Keefe, S J; Adam, J K; Cakata, E; Epstein, S

    1984-01-01

    The effectiveness of two commonly available liquid diets was assessed in 40 severely malnourished black African patients. All patients were shown to have normal xylose absorption. The diets were given according to the manufacturer's recommendations. One diet was lactose containing (LC diet) (150 g/d) and high protein (112 g/d), the other normal protein and lactose free (LF diet) (protein 67 g/d), total energy content being similar. Patients were randomly divided into two equal groups and allocated (blind) to one of the diets. Tolerance and nitrogen balance were assessed over two three day periods on half and then full strength formulations. Severe intolerant symptoms were observed in 50% of patients on half strength and 94% of patients on full strength lactose containing diet with evidence of malabsorption of fluid, nitrogen, and fat. Despite high stool nitrogen losses (3.75 +/- 1.04 g/d), however, positive nitrogen balance was achieved in most patients receiving the full strength LC formulation. On the other hand, the full strength LF diet was generally well tolerated and was associated with significantly lower faecal losses and positive nitrogen balance. The results indicate that high density lactose containing liquid formulae are poorly tolerated by severely malnourished black African patients, while lactose free formulae containing approximately 10 g nitrogen/d are well tolerated and result in positive nitrogen balance. PMID:6469079

  7. African American Young Adult Smoking Initiation: Identifying Intervention Points and Prevention Opportunities

    ERIC Educational Resources Information Center

    Cheney, Marshall K.; Mansker, Jacqueline

    2014-01-01

    Background: African Americans have one of the lowest smoking rates as teens yet have one of the highest smoking rates as adults. Approximately 40% of African Americans who have ever smoked started smoking between the ages of 18 and 21. Purpose: This study aimed to identify why African American young adults began smoking in young adulthood and what…

  8. Calculator Function Approximation.

    ERIC Educational Resources Information Center

    Schelin, Charles W.

    1983-01-01

    The general algorithm used in most hand calculators to approximate elementary functions is discussed. Comments on tabular function values and on computer function evaluation are given first; then the CORDIC (Coordinate Rotation Digital Computer) scheme is described. (MNS)

  9. Black African Traditional Mathematics

    ERIC Educational Resources Information Center

    Zaslavsky, Claudia

    1970-01-01

    Discusses the traditional number systems and the origin of the number names used by several African peoples living south of the Sahara. Also included are limitations in African mathematical development, and possible topics for research. (RP)

  10. Approximate spatial reasoning

    NASA Technical Reports Server (NTRS)

    Dutta, Soumitra

    1988-01-01

    Much of human reasoning is approximate in nature. Formal models of reasoning traditionally try to be precise and reject the fuzziness of concepts in natural use and replace them with non-fuzzy scientific explicata by a process of precisiation. As an alternate to this approach, it has been suggested that rather than regard human reasoning processes as themselves approximating to some more refined and exact logical process that can be carried out with mathematical precision, the essence and power of human reasoning is in its capability to grasp and use inexact concepts directly. This view is supported by the widespread fuzziness of simple everyday terms (e.g., near tall) and the complexity of ordinary tasks (e.g., cleaning a room). Spatial reasoning is an area where humans consistently reason approximately with demonstrably good results. Consider the case of crossing a traffic intersection. We have only an approximate idea of the locations and speeds of various obstacles (e.g., persons and vehicles), but we nevertheless manage to cross such traffic intersections without any harm. The details of our mental processes which enable us to carry out such intricate tasks in such apparently simple manner are not well understood. However, it is that we try to incorporate such approximate reasoning techniques in our computer systems. Approximate spatial reasoning is very important for intelligent mobile agents (e.g., robots), specially for those operating in uncertain or unknown or dynamic domains.

  11. Approximate kernel competitive learning.

    PubMed

    Wu, Jian-Sheng; Zheng, Wei-Shi; Lai, Jian-Huang

    2015-03-01

    Kernel competitive learning has been successfully used to achieve robust clustering. However, kernel competitive learning (KCL) is not scalable for large scale data processing, because (1) it has to calculate and store the full kernel matrix that is too large to be calculated and kept in the memory and (2) it cannot be computed in parallel. In this paper we develop a framework of approximate kernel competitive learning for processing large scale dataset. The proposed framework consists of two parts. First, it derives an approximate kernel competitive learning (AKCL), which learns kernel competitive learning in a subspace via sampling. We provide solid theoretical analysis on why the proposed approximation modelling would work for kernel competitive learning, and furthermore, we show that the computational complexity of AKCL is largely reduced. Second, we propose a pseudo-parallelled approximate kernel competitive learning (PAKCL) based on a set-based kernel competitive learning strategy, which overcomes the obstacle of using parallel programming in kernel competitive learning and significantly accelerates the approximate kernel competitive learning for large scale clustering. The empirical evaluation on publicly available datasets shows that the proposed AKCL and PAKCL can perform comparably as KCL, with a large reduction on computational cost. Also, the proposed methods achieve more effective clustering performance in terms of clustering precision against related approximate clustering approaches. PMID:25528318

  12. The African Connection

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2012-01-01

    From student and faculty exchanges to joint research projects, U.S. universities maintain a broad spectrum of collaborative relationships with African universities. It's unclear how many U.S. colleges and universities have partnerships with African universities. The African Studies Association, an organization of scholars, doesn't keep that kind…

  13. Covariant approximation averaging

    NASA Astrophysics Data System (ADS)

    Shintani, Eigo; Arthur, Rudy; Blum, Thomas; Izubuchi, Taku; Jung, Chulwoo; Lehner, Christoph

    2015-06-01

    We present a new class of statistical error reduction techniques for Monte Carlo simulations. Using covariant symmetries, we show that correlation functions can be constructed from inexpensive approximations without introducing any systematic bias in the final result. We introduce a new class of covariant approximation averaging techniques, known as all-mode averaging (AMA), in which the approximation takes account of contributions of all eigenmodes through the inverse of the Dirac operator computed from the conjugate gradient method with a relaxed stopping condition. In this paper we compare the performance and computational cost of our new method with traditional methods using correlation functions and masses of the pion, nucleon, and vector meson in Nf=2 +1 lattice QCD using domain-wall fermions. This comparison indicates that AMA significantly reduces statistical errors in Monte Carlo calculations over conventional methods for the same cost.

  14. Fast approximate motif statistics.

    PubMed

    Nicodème, P

    2001-01-01

    We present in this article a fast approximate method for computing the statistics of a number of non-self-overlapping matches of motifs in a random text in the nonuniform Bernoulli model. This method is well suited for protein motifs where the probability of self-overlap of motifs is small. For 96% of the PROSITE motifs, the expectations of occurrences of the motifs in a 7-million-amino-acids random database are computed by the approximate method with less than 1% error when compared with the exact method. Processing of the whole PROSITE takes about 30 seconds with the approximate method. We apply this new method to a comparison of the C. elegans and S. cerevisiae proteomes. PMID:11535175

  15. The Guiding Center Approximation

    NASA Astrophysics Data System (ADS)

    Pedersen, Thomas Sunn

    The guiding center approximation for charged particles in strong magnetic fields is introduced here. This approximation is very useful in situations where the charged particles are very well magnetized, such that the gyration (Larmor) radius is small compared to relevant length scales of the confinement device, and the gyration is fast relative to relevant timescales in an experiment. The basics of motion in a straight, uniform, static magnetic field are reviewed, and are used as a starting point for analyzing more complicated situations where more forces are present, as well as inhomogeneities in the magnetic field -- magnetic curvature as well as gradients in the magnetic field strength. The first and second adiabatic invariant are introduced, and slowly time-varying fields are also covered. As an example of the use of the guiding center approximation, the confinement concept of the cylindrical magnetic mirror is analyzed.

  16. Monotone Boolean approximation

    SciTech Connect

    Hulme, B.L.

    1982-12-01

    This report presents a theory of approximation of arbitrary Boolean functions by simpler, monotone functions. Monotone increasing functions can be expressed without the use of complements. Nonconstant monotone increasing functions are important in their own right since they model a special class of systems known as coherent systems. It is shown here that when Boolean expressions for noncoherent systems become too large to treat exactly, then monotone approximations are easily defined. The algorithms proposed here not only provide simpler formulas but also produce best possible upper and lower monotone bounds for any Boolean function. This theory has practical application for the analysis of noncoherent fault trees and event tree sequences.

  17. Range and Frequency of Africanized Honey Bees in California (USA)

    PubMed Central

    Kono, Yoshiaki; Kohn, Joshua R.

    2015-01-01

    Africanized honey bees entered California in 1994 but few accounts of their northward expansion or their frequency relative to European honey bees have been published. We used mitochondrial markers and morphometric analyses to determine the prevalence of Africanized honeybees in San Diego County and their current northward progress in California west of the Sierra Nevada crest. The northernmost African mitotypes detected were approximately 40 km south of Sacramento in California’s central valley. In San Diego County, 65% of foraging honey bee workers carry African mitochondria and the estimated percentage of Africanized workers using morphological measurements is similar (61%). There was no correlation between mitotype and morphology in San Diego County suggesting Africanized bees result from bidirectional hybridization. Seventy percent of feral hives, but only 13% of managed hives, sampled in San Diego County carried the African mitotype indicating that a large fraction of foraging workers in both urban and rural San Diego County are feral. We also found a single nucleotide polymorphism at the DNA barcode locus COI that distinguishes European and African mitotypes. The utility of this marker was confirmed using 401 georeferenced honey bee sequences from the worldwide Barcode of Life Database. Future censuses can determine whether the current range of the Africanized form is stable, patterns of introgression at nuclear loci, and the environmental factors that may limit the northern range of the Africanized honey bee. PMID:26361047

  18. Approximating Integrals Using Probability

    ERIC Educational Resources Information Center

    Maruszewski, Richard F., Jr.; Caudle, Kyle A.

    2005-01-01

    As part of a discussion on Monte Carlo methods, which outlines how to use probability expectations to approximate the value of a definite integral. The purpose of this paper is to elaborate on this technique and then to show several examples using visual basic as a programming tool. It is an interesting method because it combines two branches of…

  19. Multicriteria approximation through decomposition

    SciTech Connect

    Burch, C. |; Krumke, S.; Marathe, M.; Phillips, C.; Sundberg, E. |

    1997-12-01

    The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of the technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. The method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) The authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing. (2) They show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.

  20. Multicriteria approximation through decomposition

    SciTech Connect

    Burch, C.; Krumke, S.; Marathe, M.; Phillips, C.; Sundberg, E.

    1998-06-01

    The authors propose a general technique called solution decomposition to devise approximation algorithms with provable performance guarantees. The technique is applicable to a large class of combinatorial optimization problems that can be formulated as integer linear programs. Two key ingredients of their technique involve finding a decomposition of a fractional solution into a convex combination of feasible integral solutions and devising generic approximation algorithms based on calls to such decompositions as oracles. The technique is closely related to randomized rounding. Their method yields as corollaries unified solutions to a number of well studied problems and it provides the first approximation algorithms with provable guarantees for a number of new problems. The particular results obtained in this paper include the following: (1) the authors demonstrate how the technique can be used to provide more understanding of previous results and new algorithms for classical problems such as Multicriteria Spanning Trees, and Suitcase Packing; (2) they also show how the ideas can be extended to apply to multicriteria optimization problems, in which they wish to minimize a certain objective function subject to one or more budget constraints. As corollaries they obtain first non-trivial multicriteria approximation algorithms for problems including the k-Hurdle and the Network Inhibition problems.

  1. The structural physical approximation conjecture

    NASA Astrophysics Data System (ADS)

    Shultz, Fred

    2016-01-01

    It was conjectured that the structural physical approximation (SPA) of an optimal entanglement witness is separable (or equivalently, that the SPA of an optimal positive map is entanglement breaking). This conjecture was disproved, first for indecomposable maps and more recently for decomposable maps. The arguments in both cases are sketched along with important related results. This review includes background material on topics including entanglement witnesses, optimality, duality of cones, decomposability, and the statement and motivation for the SPA conjecture so that it should be accessible for a broad audience.

  2. Linkages of remote sea surface temperatures and Atlantic tropical cyclone activity mediated by the African monsoon

    NASA Astrophysics Data System (ADS)

    Taraphdar, Sourav; Leung, L. Ruby; Hagos, Samson

    2015-01-01

    sea surface temperatures (SSTs) in North Atlantic and Mediterranean (NAMED) can influence tropical cyclone (TC) activity in the tropical East Atlantic by modulating summer convection over western Africa. Analysis of 30 years of observations demonstrates that warm NAMED SST is linked to a strengthening of the Saharan heat low and enhancement of moisture and moist static energy in the lower troposphere over West Africa, which favors a northward displacement of the monsoonal front. These processes also lead to a northward shift of the African easterly jet that introduces an anomalous positive vorticity from western Africa to the main development region (50°W-20°E; 10°N-20°N) of Atlantic TCs. By modulating multiple African monsoon processes, NAMED SST explains comparable and approximately one third of the interannual variability of Atlantic TC frequency as that explained by local wind shear and local SST, respectively, which are known key factors that influence Atlantic TC development.

  3. Servitude to Service: African-American Women as Wage Earners.

    ERIC Educational Resources Information Center

    Koman, Rita G.

    1997-01-01

    Presents a lesson plan that examines how the employment position of African-American women changed due to southern economic policies established after emancipation. Uses primary documents to assist in analyzing social and economic discrimination against African-American women in the work force. (MJP)

  4. Work Stress in the Family Life of African Americans.

    ERIC Educational Resources Information Center

    Broman, Clifford L.

    2001-01-01

    Investigated the link between job-related stressors and family life among African Americans. Data from African Americans who participated in the America's Changing Lives survey indicated that job latitude positively affected marital harmony, and physical demands negatively affected marital harmony. Psychosocial demands, job bother, and chronic…

  5. Resiliency Instructional Tactics: African American Students with Learning Disabilities

    ERIC Educational Resources Information Center

    Jones, Vita L.

    2011-01-01

    Schools and classrooms, if well conceived, can serve as protective environments for the positive development of African American students with learning disabilities (LD) (Keogh & Weisner, 1993). Many African American students who lack resiliency often struggle with life's challenges and may be predisposed to negative outcomes in life, so the focus…

  6. Boys into Men: Raising Our African American Teenage Sons.

    ERIC Educational Resources Information Center

    Boyd-Franklin, Nancy; Franklin, A. J.

    This guide to rearing African American boys offers simple and effective strategies for problem-solving, improving communication, and instilling a positive racial identity. The book draws on strong African American family values and cultural and spiritual strengths. The chapters are: (1) "You Must Act As If It Is Impossible To Fail: Challenges in…

  7. Complicating Culturally Relevant Pedagogy: Unpacking West African Immigrants' Cultural Identities

    ERIC Educational Resources Information Center

    Allen, Keisha McIntosh; Jackson, Iesha; Knight, Michelle G.

    2012-01-01

    This study presents findings from a case study of 18 second- and 1.5-generation West African immigrants. We draw upon notions of elusive culture and indigenous knowledges to highlight participants' complex cultural identities and respond to anti-immigration discourses through positioning West African immigrant students as assets in American…

  8. Using the Afrocentric Method in Researching Indigenous African Culture

    ERIC Educational Resources Information Center

    Mkabela, Queeneth

    2005-01-01

    The article highlights the realities and dynamics facing researchers researching indigenous African culture. The cultural aspirations, understandings, and practices of African indigenous people should position researchers to implement and organize the research process. Suggestions are also made for implementing the "Afrocentric method," and how to…

  9. [West African childbirth traditions].

    PubMed

    Hallgren, R

    1983-11-01

    Religious and medical practices are steeped in the traditions of West African culture vis-a-vis childbirth. It is customary for delivery to occur with the woman squatting on the ground surrounded by sisters and female relatives, some of whom function as midwives. Midwives get paid only if delivery is successful. A stool is also often used in childbirth. The name given to a child in the Yoruba tribe in Nigeria has to refer to the circumstances of the individual's birth. The contact with the earth (as in the squatting position) has religious overtones--it indicates the fecundity of the earth, and the mother's contact with it. Infertility is considered the greatest tragedy in traditional African society. In Senegal, a childless woman pays a fertile one a certain sum in return for bearing her a child who would be raised as her own (this tradition is not unlike surrogate motherhood in Western countries). Men are never present at birth; however, in urban settings this practice is changing. The burial of the placenta and umbilical cord is thought to restore the woman's fertility and help heal her womb. This practice was even recorded in 19th century Sweden harkening back to heathen times. In Ghana, an infertile woman urinates on the ground where the placenta is buried in the belief that her fertility will be restored. The birth of twins is regarded as a great blessing, and as a sign of fertility; however, the inability of the mother to breast-feed both twins may result in the death of the weaker child. The harmony of nature, animals, and human beings is paramount in traditional West Africa religion and life, and undoubtedly Western culture could learn from some of these beliefs. PMID:6558064

  10. Constructing an Authentic Self: The Challenges and Promise of African-Centered Pedagogy

    ERIC Educational Resources Information Center

    Merry, Michael S.; New, William

    2008-01-01

    African-centered pedagogy aims to cultivate a positive and productive culturally based identity for Black children, and African-centered schools endeavor to supply that cultural base, placing the history, culture, and life experiences of individuals of African descent at the center of everything that they do. Our study examines the historical…

  11. Early Head Start and African American Families: Impacts and Mechanisms of Child Outcomes

    ERIC Educational Resources Information Center

    Harden, Brenda Jones; Sandstrom, Heather; Chazan-Cohen, Rachel

    2012-01-01

    Persistent disparities exist between African American children and their European American counterparts across developmental domains. Early childhood intervention may serve to promote more positive outcomes among African American children. The current study examined whether and how the Early Head Start (EHS) program benefited African American…

  12. Approximate option pricing

    SciTech Connect

    Chalasani, P.; Saias, I.; Jha, S.

    1996-04-08

    As increasingly large volumes of sophisticated options (called derivative securities) are traded in world financial markets, determining a fair price for these options has become an important and difficult computational problem. Many valuation codes use the binomial pricing model, in which the stock price is driven by a random walk. In this model, the value of an n-period option on a stock is the expected time-discounted value of the future cash flow on an n-period stock price path. Path-dependent options are particularly difficult to value since the future cash flow depends on the entire stock price path rather than on just the final stock price. Currently such options are approximately priced by Monte carlo methods with error bounds that hold only with high probability and which are reduced by increasing the number of simulation runs. In this paper the authors show that pricing an arbitrary path-dependent option is {number_sign}-P hard. They show that certain types f path-dependent options can be valued exactly in polynomial time. Asian options are path-dependent options that are particularly hard to price, and for these they design deterministic polynomial-time approximate algorithms. They show that the value of a perpetual American put option (which can be computed in constant time) is in many cases a good approximation to the value of an otherwise identical n-period American put option. In contrast to Monte Carlo methods, the algorithms have guaranteed error bounds that are polynormally small (and in some cases exponentially small) in the maturity n. For the error analysis they derive large-deviation results for random walks that may be of independent interest.

  13. Beyond the Kirchhoff approximation

    NASA Technical Reports Server (NTRS)

    Rodriguez, Ernesto

    1989-01-01

    The three most successful models for describing scattering from random rough surfaces are the Kirchhoff approximation (KA), the small-perturbation method (SPM), and the two-scale-roughness (or composite roughness) surface-scattering (TSR) models. In this paper it is shown how these three models can be derived rigorously from one perturbation expansion based on the extinction theorem for scalar waves scattering from perfectly rigid surface. It is also shown how corrections to the KA proportional to the surface curvature and higher-order derivatives may be obtained. Using these results, the scattering cross section is derived for various surface models.

  14. The African superswell

    NASA Technical Reports Server (NTRS)

    Nyblade, Andrew A.; Robinson, Scott W.

    1994-01-01

    Maps of residual bathymetry in the ocean basins around the African continent reveal a broad bathymetric swell in the southeastern Atlantic Ocean with an amplitude of about 500 m. We propose that this region of anomalously shallow bathymetry, together with the contiguous eastern and southern African plateaus, form a superswell which we refer to as the African superswell. The origin of the African superswell is uncertain. However, rifting and volcanism in eastern Africa, as well as heat flow measurements in southern Africa and the southeastern Atlantic Ocean, suggest that the superswell may be attributed, at least in part, to heating of the lithosphere.

  15. IDEAL Symposium on the East African Lakes

    NASA Astrophysics Data System (ADS)

    Johnson, T. C.; Kelts, K.; Lehman, J. T.; Wuest, A.

    A vast array of interdisciplinary problems presented by the African Great Lakes were highlighted at the International Symposium on the Limnology, Climatology and Paleoclimatology of the East African Lakes, organized by the International Decade for the East African Lakes (IDEAL) February 17-21 in Jinja, Uganda. Approximately 125 scientists attended from North America, Europe, Africa, and New Zealand. Jinja is located on the northern shore of Lake Victoria at the head-waters of the Nile and is the site of the host institution for the symposium, the Uganda Freshwater Fisheries Research Organization (UFFRO). The conveners of the symposium were Tom Johnson of Duke University, George Kitaka of UNESCO-ROSTA, and Eric Odada of the University of Nairobi.

  16. Trichomonas vaginalis, HIV, and African-Americans.

    PubMed Central

    Sorvillo, F.; Smith, L.; Kerndt, P.; Ash, L.

    2001-01-01

    Trichomonas vaginalis may be emerging as one of the most important cofactors in amplifying HIV transmission, particularly in African-American communities of the United States. In a person co-infected with HIV, the pathology induced by T. vaginalis infection can increase HIV shedding. Trichomonas infection may also act to expand the portal of entry for HIV in an HIV-negative person. Studies from Africa have suggested that T. vaginalis infection may increase the rate of HIV transmission by approximately twofold. Available data indicate that T. vaginalis is highly prevalent among African-Americans in major urban centers of the United States and is often the most common sexually transmitted infection in black women. Even if T. vaginalis increases the risk of HIV transmission by a small amount, this could translate into an important amplifying effect since Trichomonas is so common. Substantial HIV transmission may be attributable to T. vaginalis in African-American communities of the United States. PMID:11747718

  17. Decreasing Discipline Referrals for African American Males in Middle School

    ERIC Educational Resources Information Center

    Moore, Earl, Jr.; Ratchford, Vicky F.

    2007-01-01

    Brogden Middle School (BMS) is located approximately 15 miles south of Goldsboro, North Carolina, a city of approximately 40,000 citizens and the home of a military base. To decrease the number of discipline referrals of African American males, 10 students who had the most frequent discipline referrals during their seventh-grade year were…

  18. A molecular phylogenetic study of southern African Apiaceae.

    PubMed

    Calviño, Carolina I; Tilney, Patricia M; Wyk, Ben-Erik van; Downie, Stephen R

    2006-12-01

    It has been suggested that southern Africa is the origin of the predominantly herbaceous Apiaceae subfamily Apioideae and that the woody habit is plesiomorphic. We expand previous molecular phylogenetic analyses of the family by considering all but three of the approximately 38 genera native to southern Africa, including all genera whose members, save one, have a woody habit. Representatives of five other genera are included because they may be closely related to these southern African taxa. Chloroplast DNA rps16 intron and/or nuclear rDNA ITS sequences for 154 accessions are analyzed using maximum parsimony, Bayesian, and maximum likelihood methods. Within Apioideae, two major clades hitherto unrecognized in the subfamily are inferred. The monogeneric Lichtensteinia clade is sister group to all other members of the subfamily, whereas the Annesorhiza clade (Annesorhiza, Chamarea, and Itasina) plus Molopospermum (and Astydamia in the ITS trees) are the successive sister group to all Apioideae except Lichtensteinia. Tribe Heteromorpheae is expanded to include Pseudocarum, "Oreofraga" ined., and five genera endemic to Madagascar. The southern African origin of subfamily Apioideae is corroborated (with subsequent migration northward into Eurasia along two dispersal routes), and the positions of the herbaceous Lichtensteinia and Annesorhiza clades within the subfamily suggest, surprisingly, that its ancestor was herbaceous, not woody. PMID:21642128

  19. 16 Extraordinary African Americans.

    ERIC Educational Resources Information Center

    Lobb, Nancy

    This collection for children tells the stories of 16 African Americans who helped make America what it is today. African Americans can take pride in the heritage of these contributors to society. Biographies are given for the following: (1) Sojourner Truth, preacher and abolitionist; (2) Frederick Douglass, abolitionist; (3) Harriet Tubman, leader…

  20. African Studies Computer Resources.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

    African studies computer resources that are readily available in the United States with linkages to Africa are described, highlighting those most directly corresponding to African content. Africanists can use the following four fundamental computer systems: (1) Internet/Bitnet; (2) Fidonet; (3) Usenet; and (4) dial-up bulletin board services. The…

  1. African Literature as Celebration.

    ERIC Educational Resources Information Center

    Achebe, Chinua

    1989-01-01

    Describes the Igbo tradition of "Mbari," a communal creative enterprise that celebrates the world and the life lived in it through art. Contrasts the cooperative, social dimension of pre-colonial African culture with the exclusion and denial of European colonialism, and sees new African literature again celebrating human presence and dignity. (AF)

  2. Educating African American Males

    ERIC Educational Resources Information Center

    Bell, Edward E.

    2010-01-01

    Background: Schools across America spend money, invest in programs, and sponsor workshops, offer teacher incentives, raise accountability standards, and even evoke the name of Obama in efforts to raise the academic achievement of African American males. Incarceration and college retention rates point to a dismal plight for many African American…

  3. Africans Away from Home.

    ERIC Educational Resources Information Center

    Clarke, John Henrik

    Africans who were brought across the Atlantic as slaves never fully adjusted to slavery or accepted its inevitability. Resistance began on board the slave ships, where many jumped overboard or committed suicide. African slaves in South America led the first revolts against tyranny in the New World. The first slave revolt in the Caribbean occurred…

  4. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  5. Countably QC-Approximating Posets

    PubMed Central

    Mao, Xuxin; Xu, Luoshan

    2014-01-01

    As a generalization of countably C-approximating posets, the concept of countably QC-approximating posets is introduced. With the countably QC-approximating property, some characterizations of generalized completely distributive lattices and generalized countably approximating posets are given. The main results are as follows: (1) a complete lattice is generalized completely distributive if and only if it is countably QC-approximating and weakly generalized countably approximating; (2) a poset L having countably directed joins is generalized countably approximating if and only if the lattice σc(L)op of all σ-Scott-closed subsets of L is weakly generalized countably approximating. PMID:25165730

  6. "I am Not a Statistic": Identities of African American Males in Advanced Science Courses

    NASA Astrophysics Data System (ADS)

    Johnson, Diane Wynn

    The United States Bureau of Labor Statistics (2010) expects new industries to generate approximately 2.7 million jobs in science and technology by the year 2018, and there is concern as to whether there will be enough trained individuals to fill these positions. A tremendous resource remains untapped, African American students, especially African American males (National Science Foundation, 2009). Historically, African American males have been omitted from the so called science pipeline. Fewer African American males pursue a science discipline due, in part; to limiting factors they experience in school and at home (Ogbu, 2004). This is a case study of African American males who are enrolled in advanced science courses at a predominantly African American (84%) urban high school. Guided by expectancy-value theory (EVT) of achievement related results (Eccles, 2009; Eccles et al., 1983), twelve African American male students in two advanced science courses were observed in their science classrooms weekly, participated in an in-depth interview, developed a presentation to share with students enrolled in a tenth grade science course, responded to an open-ended identity questionnaire, and were surveyed about their perceptions of school. Additionally, the students' teachers were interviewed, and seven of the students' parents. The interview data analyses highlighted the important role of supportive parents (key socializers) who had high expectations for their sons and who pushed them academically. The students clearly attributed their enrollment in advanced science courses to their high regard for their science teachers, which included positive relationships, hands-on learning in class, and an inviting and encouraging learning environment. Additionally, other family members and coaches played important roles in these young men's lives. Students' PowerPoint(c) presentations to younger high school students on why they should take advanced science courses highlighted these

  7. Diabetes in African Americans

    PubMed Central

    Marshall, M

    2005-01-01

    African Americans have a high risk for type 2 diabetes. Genetic traits, the prevalence of obesity, and insulin resistance all contribute to the risk of diabetes in the African American community. African Americans have a high rate of diabetic complications, because of poor glycaemic control and racial disparities in health care in the USA. African Americans with diabetes may have an atypical presentation that simulates type 1 diabetes, but then their subsequent clinical course is typical of type 2 diabetes. Culturally sensitive strategies, structured disease management protocols, and the assistance of nurses, diabetic educators, and other health care professionals are effective in improving the outcome of diabetes in the African American community. PMID:16344294

  8. Educational Resilience in African American Adolescents

    ERIC Educational Resources Information Center

    Cunningham, Michael; Swanson, Dena Phillips

    2010-01-01

    The purpose of this article was to examine factors within the school context that facilitates educational resilience among African American high school students. The authors expected academic self-esteem to be positively associated with future expectations (academic and general). They expected perceptions of school-based social support to have…

  9. Approximate Bayesian multibody tracking.

    PubMed

    Lanz, Oswald

    2006-09-01

    Visual tracking of multiple targets is a challenging problem, especially when efficiency is an issue. Occlusions, if not properly handled, are a major source of failure. Solutions supporting principled occlusion reasoning have been proposed but are yet unpractical for online applications. This paper presents a new solution which effectively manages the trade-off between reliable modeling and computational efficiency. The Hybrid Joint-Separable (HJS) filter is derived from a joint Bayesian formulation of the problem, and shown to be efficient while optimal in terms of compact belief representation. Computational efficiency is achieved by employing a Markov random field approximation to joint dynamics and an incremental algorithm for posterior update with an appearance likelihood that implements a physically-based model of the occlusion process. A particle filter implementation is proposed which achieves accurate tracking during partial occlusions, while in cases of complete occlusion, tracking hypotheses are bound to estimated occlusion volumes. Experiments show that the proposed algorithm is efficient, robust, and able to resolve long-term occlusions between targets with identical appearance. PMID:16929730

  10. An approximate model for pulsar navigation simulation

    NASA Astrophysics Data System (ADS)

    Jovanovic, Ilija; Enright, John

    2016-02-01

    This paper presents an approximate model for the simulation of pulsar aided navigation systems. High fidelity simulations of these systems are computationally intensive and impractical for simulating periods of a day or more. Simulation of yearlong missions is done by abstracting navigation errors as periodic Gaussian noise injections. This paper presents an intermediary approximate model to simulate position errors for periods of several weeks, useful for building more accurate Gaussian error models. This is done by abstracting photon detection and binning, replacing it with a simple deterministic process. The approximate model enables faster computation of error injection models, allowing the error model to be inexpensively updated throughout a simulation. Testing of the approximate model revealed an optimistic performance prediction for non-millisecond pulsars with more accurate predictions for pulsars in the millisecond spectrum. This performance gap was attributed to noise which is not present in the approximate model but can be predicted and added to improve accuracy.

  11. African bees to control African elephants

    NASA Astrophysics Data System (ADS)

    Vollrath, Fritz; Douglas-Hamilton, Iain

    2002-11-01

    Numbers of elephants have declined in Africa and Asia over the past 30 years while numbers of humans have increased, both substantially. Friction between these two keystone species is reaching levels which are worryingly high from an ecological as well as a political viewpoint. Ways and means must be found to keep the two apart, at least in areas sensitive to each species' survival. The aggressive African bee might be one such method. Here we demonstrate that African bees deter elephants from damaging the vegetation and trees which house their hives. We argue that bees can be employed profitably to protect not only selected trees, but also selected areas, from elephant damage.

  12. Approximation by hinge functions

    SciTech Connect

    Faber, V.

    1997-05-01

    Breiman has defined {open_quotes}hinge functions{close_quotes} for use as basis functions in least squares approximations to data. A hinge function is the max (or min) function of two linear functions. In this paper, the author assumes the existence of smooth function f(x) and a set of samples of the form (x, f(x)) drawn from a probability distribution {rho}(x). The author hopes to find the best fitting hinge function h(x) in the least squares sense. There are two problems with this plan. First, Breiman has suggested an algorithm to perform this fit. The author shows that this algorithm is not robust and also shows how to create examples on which the algorithm diverges. Second, if the author tries to use the data to minimize the fit in the usual discrete least squares sense, the functional that must be minimized is continuous in the variables, but has a derivative which jumps at the data. This paper takes a different approach. This approach is an example of a method that the author has developed called {open_quotes}Monte Carlo Regression{close_quotes}. (A paper on the general theory is in preparation.) The author shall show that since the function f is continuous, the analytic form of the least squares equation is continuously differentiable. A local minimum is solved for by using Newton`s method, where the entries of the Hessian are estimated directly from the data by Monte Carlo. The algorithm has the desirable properties that it is quadratically convergent from any starting guess sufficiently close to a solution and that each iteration requires only a linear system solve.

  13. Novel African Trypanocidal Agents: Membrane Rigidifying Peptides

    PubMed Central

    Harrington, John M.; Scelsi, Chris; Hartel, Andreas; Jones, Nicola G.; Engstler, Markus; Capewell, Paul; MacLeod, Annette; Hajduk, Stephen

    2012-01-01

    The bloodstream developmental forms of pathogenic African trypanosomes are uniquely susceptible to killing by small hydrophobic peptides. Trypanocidal activity is conferred by peptide hydrophobicity and charge distribution and results from increased rigidity of the plasma membrane. Structural analysis of lipid-associated peptide suggests a mechanism of phospholipid clamping in which an internal hydrophobic bulge anchors the peptide in the membrane and positively charged moieties at the termini coordinate phosphates of the polar lipid headgroups. This mechanism reveals a necessary phenotype in bloodstream form African trypanosomes, high membrane fluidity, and we suggest that targeting the plasma membrane lipid bilayer as a whole may be a novel strategy for the development of new pharmaceutical agents. Additionally, the peptides we have described may be valuable tools for probing the biosynthetic machinery responsible for the unique composition and characteristics of African trypanosome plasma membranes. PMID:22970207

  14. Black versus Black: The Relationship among African, African American, and African Caribbean Persons.

    ERIC Educational Resources Information Center

    Jackson, Jennifer V.; Cothran, Mary E.

    2003-01-01

    Surveyed people of African descent regarding relationships among African, African-American, and African-Caribbean persons, focusing on contact and friendship, travel to countries of the diaspora, cross-cultural communication, thoughts and stereotypes, and education. Most respondents had contacts with the other groups, but groups had preconceived…

  15. Africanized honeybees are slower learners than their European counterparts

    NASA Astrophysics Data System (ADS)

    Couvillon, Margaret J.; Degrandi-Hoffman, Gloria; Gronenberg, Wulfila

    2010-02-01

    Does cognitive ability always correlate with a positive fitness consequence? Previous research in both vertebrates and invertebrates provides mixed results. Here, we compare the learning and memory abilities of Africanized honeybees ( Apis mellifera scutellata hybrid) and European honeybees ( Apis mellifera ligustica). The range of the Africanized honeybee continues to expand, superseding the European honeybee, which led us to hypothesize that they might possess greater cognitive capabilities as revealed by a classical conditioning assay. Surprisingly, we found that fewer Africanized honeybees learn to associate an odor with a reward. Additionally, fewer Africanized honeybees remembered the association a day later. While Africanized honeybees are replacing European honeybees, our results show that they do so despite displaying a relatively poorer performance on an associative learning paradigm.

  16. Astronomy for African development

    NASA Astrophysics Data System (ADS)

    Govender, Kevindran

    2011-06-01

    In recent years there have been a number of efforts across Africa to develop the field of astronomy as well as to reap benefit from astronomy for African people. This presentation will discuss the case of the SALT (Southern African Large Telescope) Collateral Benefits Programme (SCBP) which was set up to ensure societal benefit from astronomy. With African society as the target, the SCBP has embarked on various projects from school level education to public understanding of science to socio-economic development, the latter mainly being felt in the rural communities surrounding the South African Astronomical Observatory (home to SALT). A development plan for ``Astronomy in Africa'' will also be discussed. This plan has been drawn up with input from all over Africa and themed ``Astronomy for Education''. The Africa case stands as a good example for the IYA cornerstone project ``Developing Astronomy Globally'' which focuses on developing regions.

  17. African American Suicide

    MedlinePlus

    ... accounted for 83.8% of Caucasian elderly suicides. • Firearms were the predominant method of suicide among African ... per 100,000 annually. Source: Centers for Disease Control and Prevention. National Vital Statistics System. Mortality Data. ...

  18. Genome-wide association of anthropometric traits in African- and African-derived populations.

    PubMed

    Kang, Sun J; Chiang, Charleston W K; Palmer, Cameron D; Tayo, Bamidele O; Lettre, Guillaume; Butler, Johannah L; Hackett, Rachel; Adeyemo, Adebowale A; Guiducci, Candace; Berzins, Ilze; Nguyen, Thutrang T; Feng, Tao; Luke, Amy; Shriner, Daniel; Ardlie, Kristin; Rotimi, Charles; Wilks, Rainford; Forrester, Terrence; McKenzie, Colin A; Lyon, Helen N; Cooper, Richard S; Zhu, Xiaofeng; Hirschhorn, Joel N

    2010-07-01

    Genome-wide association (GWA) studies have identified common variants that are associated with a variety of traits and diseases, but most studies have been performed in European-derived populations. Here, we describe the first genome-wide analyses of imputed genotype and copy number variants (CNVs) for anthropometric measures in African-derived populations: 1188 Nigerians from Igbo-Ora and Ibadan, Nigeria, and 743 African-Americans from Maywood, IL. To improve the reach of our study, we used imputation to estimate genotypes at approximately 2.1 million single-nucleotide polymorphisms (SNPs) and also tested CNVs for association. No SNPs or common CNVs reached a genome-wide significance level for association with height or body mass index (BMI), and the best signals from a meta-analysis of the two cohorts did not replicate in approximately 3700 African-Americans and Jamaicans. However, several loci previously confirmed in European populations showed evidence of replication in our GWA panel of African-derived populations, including variants near IHH and DLEU7 for height and MC4R for BMI. Analysis of global burden of rare CNVs suggested that lean individuals possess greater total burden of CNVs, but this finding was not supported in an independent European population. Our results suggest that there are not multiple loci with strong effects on anthropometric traits in African-derived populations and that sample sizes comparable to those needed in European GWA studies will be required to identify replicable associations. Meta-analysis of this data set with additional studies in African-ancestry populations will be helpful to improve power to detect novel associations. PMID:20400458

  19. A Phenomenological Study of Urban African American Males Who Aspire to Attend a Four-Year University

    ERIC Educational Resources Information Center

    Steppes, Allison Victoria

    2011-01-01

    In the United States, less than 30% of African American males between the ages of 18 and 24 are enrolled in a 4-year university. More African American females are enrolled in colleges than their male counterparts. Focusing on the positive aspects of some African American males' educational experiences, this research was conducted to learn how some…

  20. "Women...mourn and men carry on": African women storying mourning practices: a South African example.

    PubMed

    Kotzé, Elmarie; Els, Lishje; Rajuili-Masilo, Ntsiki

    2012-09-01

    African mourning of loss of lives in South Africa has been shaped by discursive practices of both traditional African cultures and the sociopolitical developments under apartheid and in post-apartheid South Africa. This article reports on changes in mourning practices on the basis of a literature review and uses a collection of examples to highlight the navigation of some cultural and gendered issues relating to mourning, against the backdrop of the everyday experiences of loss of life in South Africa due to violence and HIV/AIDS. The article draws on African womanist and feminist scholarship and focuses on the intersections between cultural and gender practices of bereavement in the lives of professional urban African women. The authors argue for the use of positioning theory and witnessing practices to honor and story the ongoing struggle of African women as these women take different agentic positions by accepting, questioning, resisting, and/or changing cultural mourning practices while they compassionately witness the self and others in the narratives they live. PMID:24563939

  1. A Model for Differential Perceptions of Competence Based on Skin Tone among African Americans.

    ERIC Educational Resources Information Center

    Breland, Alfiee M.

    1998-01-01

    Combines a review of the psychological and sociohistorical literature on African-American color consciousness with a model that explains how it may contribute to differential outcomes for group members. Hypothesizes that attractive individuals are viewed as more competent, and that African Americans who approximate European-American standards of…

  2. The Factors Affecting the Career Choices of African Americans and Three Career Counseling Suggestions.

    ERIC Educational Resources Information Center

    Harrington, Susan G.

    This paper identifies and explores three major factors that affect the career choices of African Americans. First, the future of the American employment market is strongly based in technology, yet approximately two-thirds of the African American population reported their level of education at high school completion and lower. Second, African…

  3. Stifled Voices: Barriers to Help-Seeking Behavior for South African Childhood Sexual Assault Survivors

    ERIC Educational Resources Information Center

    Smith, Kimberly; Bryant-Davis, Thema; Tillman, Shaquita; Marks, Alison

    2010-01-01

    In South Africa, females under the age of 18 comprise approximately 40% of the rapes and other forms of sexual assault that occur. However, South African girls face multiple barriers to seeking help in the aftermath of sexual assault. This literature review provides an overview of childhood sexual assault in South African girls and addresses…

  4. Biological evaluation of Trans-African highways

    NASA Astrophysics Data System (ADS)

    Adamatzky, Andrew; Kayem, Anne V. D. M.

    2013-01-01

    The Trans-African highway network is a unique concept of integrated development of transport corridors spanning all African countries and providing landlocked countries access to seaports. The planned road system is still maturing and just partially complete, thus giving us a chance to play with different scenarios of its growth and to consider potential alternative transport networks. We study the evolving transport network in the African continent with a groundbreaking technique of imitating growing transport networks with slime mould Physarum polycephalum. We represent the major urban areas of Africa with a source of nutrients, inoculate a piece of the slime mould in Cairo and allow the mould to span all urban areas with its network of protoplasmic tubes. We then compare the slime mould networks with existing and planned highway corridors. We found that slime mould provides a good approximation of the Trans-African highway network, with some roads of Eastern Africa delineated by P. polycephalum in a larger number of laboratory experiments. We demonstrate direct matches between protoplasmic tubes and Trans-Sahelian as well as Lagos-Mombasa corridors. Finally we analyse the bio-logic of transport network development in families of generalised Physarum graphs.

  5. "Give a Brotha a Break!": The Experiences and Dilemmas of Middle-Class African American Male Students in White Suburban Schools

    ERIC Educational Resources Information Center

    Gordon, Beverly M.

    2012-01-01

    Background/Context: Today, in the era of the first African American president, approximately one third of all African Americans live in suburban communities, and their children are attending suburban schools. Although most research on the education of African American students, particularly males, focuses on their plight in urban schooling, what…

  6. Thyroid c-cell carcinoma in an African pygmy hedgehog (Atelerix albiventris).

    PubMed

    Miller, Debra L; Styer, Eloise L; Stobaeus, Janeen K; Norton, Terry M

    2002-12-01

    A 3-yr-old African pygmy hedgehog (Atelerix albiventris) was submitted with dysphagia, weight loss, and tetraparesis. A palpable mass was found on the ventral neck. Histologic examination revealed replacement of the thyroid gland by a highly cellular, expansile, and infiltrative mass composed of lobules of polygonal cells separated by fine fibrovascular septa. Examination of ultrathin sections revealed tumor cells with few to many dense-core neuroendocrine granules, approximately 100-200 nm in diameter, and stromal amyloid. Immunohistochemical stains were positive for neuron-specific enolase. Only rare cells had positive immunohistochemical staining for calcitonin. Findings are consistent with a neuroendocrine tumor of C-cell origin. This is the first report of a C-cell carcinoma in a hedgehog. PMID:12564541

  7. South African AIDS plan criticised.

    PubMed

    Sidley, P

    1998-10-17

    In a television broadcast, Deputy President Mbeki of South Africa announced a campaign against HIV/AIDS that would involve coordination between various government departments and nongovernmental organizations. Mbeki, who is associated with Virodene (a drug treatment for AIDS that is considered a scam), replaced President Mandela at the last minute in the broadcast. Two days after the broadcast, the government refused to support treatment of pregnant women infected with HIV with zidovudine to prevent transmission of the virus to the baby. The treatment is considered cost-effective by AIDS workers and public health officials. According to Mark Heywood of the AIDS law project at Witwatersrand University, 16% of pregnant women attending antenatal clinics were HIV-positive in 1997; this means that about 3 million South Africans (8% of the population) were living with HIV. Heywood said that the government believes there are 1500 new cases daily. By the end of 1998, 3.5 million South Africans will be living with HIV. Although the government is asking other sectors to join in the campaign, what the government is doing is unclear. Mother-to-child transmission of HIV is second only to transmission of the virus through heterosexual sex in South Africa. PMID:9841037

  8. Recommendations for the Use of Online Social Support for African American Men

    PubMed Central

    Watkins, Daphne C.; Jefferson, S. Olivia

    2014-01-01

    African American men face greater psychosocial stressors than African American women and men of other racial and ethnic groups, which place them at higher risk for psychological distress. Yet, research suggests that African Americans are less likely to utilize professional mental health services because of their mistrust of the health care system and their need for more specialized and innovative services. Supplemental resources aimed at positive coping and social support for African American men may reduce the likelihood that they experience psychological distress, which could lead to more severe mental disorders. This article proposes the use of online social support for African American men who are in early, nonsevere stages of psychological distress. We examine the unique experiences of African American men, discuss distress among this underserved group, and finally, offer recommendations for achieving an online community for African American men. PMID:22924797

  9. African-Americans and Alzheimer's

    MedlinePlus

    ... Share Plus on Google Plus African-Americans and Alzheimer's alz.org | IHaveAlz Introduction 10 Warning Signs Brain ... African-Americans are at a higher risk for Alzheimer's disease. Many Americans dismiss the warning signs of ...

  10. Training African-American residents in the 20th century.

    PubMed

    Green-McKenzie, Judith

    2004-03-01

    Bellevue Hospital, the oldest public hospital in the United States and a lineal descendant of an infirmary for slaves, accepted its first African-American resident, Dr. Ubert Conrad Vincent, in 1918. This occurred at a time when many medical centers were not accepting African-American residents. At the end of WWII, one-third of the accredited medical schools still barred African Americans. However, Bellevue Hospital continued to train African-American residents. Between the 1920s and 1940s four African Americans matriculated at Bellevue Hospital. There were six in the 1950s, four in the 1960s, and 25 in the 1970s. By the 1980s, 40 African Americans matriculated, and between 1990 and 1995, 61 matriculated. Despite its historic first, Bellevue lagged slightly behind the national average. While the number of African-American residents occupying U.S. residency slots increased from 2.8% in 1978 to 6.5% in 1996, African Americans comprised 3.6% of residency slots at Bellevue between 1985-1995. Currently, only 7% of practicing physicians and 5% in faculty positions are latino, African-American, and Native American. Increasing the number of under-represented minority (URM) physicians is important to the United States, as URM physicians are more likely to serve the poor and uninsured, therefore improving the overall healthcare of the underprivileged. A study by the Association of American Medical Colleges indicated that minority medical school graduates were five times more likely to report that they planned to serve minority populations than other graduates. In their position paper, the American College of Physicians expressed the belief that increasing the number of URM physicians will help reduce healthcare disparities that can hurt minority populations and lead to poor health outcomes. The Supreme Court acknowledged the importance of racial diversity by upholding the University of Michigan affirmative action admissions policy in its June 2003 ruling. URM physicians are

  11. Ancilla-approximable quantum state transformations

    SciTech Connect

    Blass, Andreas; Gurevich, Yuri

    2015-04-15

    We consider the transformations of quantum states obtainable by a process of the following sort. Combine the given input state with a specially prepared initial state of an auxiliary system. Apply a unitary transformation to the combined system. Measure the state of the auxiliary subsystem. If (and only if) it is in a specified final state, consider the process successful, and take the resulting state of the original (principal) system as the result of the process. We review known information about exact realization of transformations by such a process. Then we present results about approximate realization of finite partial transformations. We not only consider primarily the issue of approximation to within a specified positive ε, but also address the question of arbitrarily close approximation.

  12. Postpartum depression among African-American women.

    PubMed

    Amankwaa, Linda Clark

    2003-01-01

    The purpose of this qualitative study was to describe the nature of postpartum depression (PPD) among African-American women. Twelve women, who had experienced PPD within the last three years, were interviewed for approximately one hour at two intervals. Nudist-4 software and the constant comparative method were used to analyze the data. Five themes "Stressing Out," "Feeling Down," "Losing It," "Seeking Help," and "Feeling Better" represented aspects of PPD as experienced by the participants. The last theme, "Dealing with It," represented the cultural ways in which African-American mothers managed their depression. These included Keeping the Faith, Trying to Be a Strong Black Woman, Living with Myths, and Keeping Secrets. Suggestions for future directions in nursing research are included. PMID:12623687

  13. The influences and experiences of African American undergraduate science majors at predominately White universities

    NASA Astrophysics Data System (ADS)

    Blockus, Linda Helen

    The purpose of this study is to describe and explore some of the social and academic experiences of successful African American undergraduate science majors at predominately White universities with the expectation of conceptualizing emerging patterns for future study. The study surveyed 80 upperclass African Americans at 11 public research universities about their perceptions of the influences that affect their educational experiences and career interests in science. The mailed survey included the Persistence/ voluntary Dropout Decision Scale, the Cultural Congruity Scale and the University Environment Scale. A variety of potential influences were considered including family background, career goals, psychosocial development, academic and social connections with the university, faculty relationships, environmental fit, retention factors, validation, participation in mentored research projects and other experiences. The students' sources of influences, opportunities for connection, and cultural values were considered in the context of a research university environment and investigated for emerging themes and direction for future research. Results indicate that performance in coursework appears to be the most salient factor in African American students' experience as science majors. The mean college gpa was 3.01 for students in this study. Challenging content, time demands, study habits and concern with poor grades all serve to discourage students; however, for most of the students in this study, it has not dissuaded them from their educational and career plans. Positive course performance provided encouragement. Science faculty provide less influence than family members, and more students find faculty members discouraging than supportive. Measures of faculty relations were not associated with academic success. No evidence was provided to confirm the disadvantages of being female in a scientific discipline. Students were concerned with lack of minority role models

  14. The Struggles over African Languages

    ERIC Educational Resources Information Center

    Maseko, Pam; Vale, Peter

    2016-01-01

    In this interview, African Language expert Pam Maseko speaks of her own background and her first encounter with culture outside of her mother tongue, isiXhosa. A statistical breakdown of South African languages is provided as background. She discusses Western (originally missionary) codification of African languages and suggests that this approach…

  15. Psychological Misdiagnosis of African Americans.

    ERIC Educational Resources Information Center

    Garretson, Deborah J.

    1993-01-01

    Reviews historical and current problems with making accurate psychological diagnoses of African Americans. Suggests that misdiagnosis is strongly related to pathologization of African-American culture itself. Explores diagnostic process, stereotypes of African-American psychopathology, cultural differences in values and life stressors, and…

  16. Fostering Formal Commutativity Knowledge with Approximate Arithmetic

    PubMed Central

    Hansen, Sonja Maria; Haider, Hilde; Eichler, Alexandra; Godau, Claudia; Frensch, Peter A.; Gaschler, Robert

    2015-01-01

    How can we enhance the understanding of abstract mathematical principles in elementary school? Different studies found out that nonsymbolic estimation could foster subsequent exact number processing and simple arithmetic. Taking the commutativity principle as a test case, we investigated if the approximate calculation of symbolic commutative quantities can also alter the access to procedural and conceptual knowledge of a more abstract arithmetic principle. Experiment 1 tested first graders who had not been instructed about commutativity in school yet. Approximate calculation with symbolic quantities positively influenced the use of commutativity-based shortcuts in formal arithmetic. We replicated this finding with older first graders (Experiment 2) and third graders (Experiment 3). Despite the positive effect of approximation on the spontaneous application of commutativity-based shortcuts in arithmetic problems, we found no comparable impact on the application of conceptual knowledge of the commutativity principle. Overall, our results show that the usage of a specific arithmetic principle can benefit from approximation. However, the findings also suggest that the correct use of certain procedures does not always imply conceptual understanding. Rather, the conceptual understanding of commutativity seems to lag behind procedural proficiency during elementary school. PMID:26560311

  17. Fostering Formal Commutativity Knowledge with Approximate Arithmetic.

    PubMed

    Hansen, Sonja Maria; Haider, Hilde; Eichler, Alexandra; Godau, Claudia; Frensch, Peter A; Gaschler, Robert

    2015-01-01

    How can we enhance the understanding of abstract mathematical principles in elementary school? Different studies found out that nonsymbolic estimation could foster subsequent exact number processing and simple arithmetic. Taking the commutativity principle as a test case, we investigated if the approximate calculation of symbolic commutative quantities can also alter the access to procedural and conceptual knowledge of a more abstract arithmetic principle. Experiment 1 tested first graders who had not been instructed about commutativity in school yet. Approximate calculation with symbolic quantities positively influenced the use of commutativity-based shortcuts in formal arithmetic. We replicated this finding with older first graders (Experiment 2) and third graders (Experiment 3). Despite the positive effect of approximation on the spontaneous application of commutativity-based shortcuts in arithmetic problems, we found no comparable impact on the application of conceptual knowledge of the commutativity principle. Overall, our results show that the usage of a specific arithmetic principle can benefit from approximation. However, the findings also suggest that the correct use of certain procedures does not always imply conceptual understanding. Rather, the conceptual understanding of commutativity seems to lag behind procedural proficiency during elementary school. PMID:26560311

  18. Cavity approximation for graphical models.

    PubMed

    Rizzo, T; Wemmenhove, B; Kappen, H J

    2007-07-01

    We reformulate the cavity approximation (CA), a class of algorithms recently introduced for improving the Bethe approximation estimates of marginals in graphical models. In our formulation, which allows for the treatment of multivalued variables, a further generalization to factor graphs with arbitrary order of interaction factors is explicitly carried out, and a message passing algorithm that implements the first order correction to the Bethe approximation is described. Furthermore, we investigate an implementation of the CA for pairwise interactions. In all cases considered we could confirm that CA[k] with increasing k provides a sequence of approximations of markedly increasing precision. Furthermore, in some cases we could also confirm the general expectation that the approximation of order k , whose computational complexity is O(N(k+1)) has an error that scales as 1/N(k+1) with the size of the system. We discuss the relation between this approach and some recent developments in the field. PMID:17677405

  19. Approximate circuits for increased reliability

    SciTech Connect

    Hamlet, Jason R.; Mayo, Jackson R.

    2015-08-18

    Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.

  20. Approximate circuits for increased reliability

    SciTech Connect

    Hamlet, Jason R.; Mayo, Jackson R.

    2015-12-22

    Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.

  1. Structural optimization with approximate sensitivities

    NASA Technical Reports Server (NTRS)

    Patnaik, S. N.; Hopkins, D. A.; Coroneos, R.

    1994-01-01

    Computational efficiency in structural optimization can be enhanced if the intensive computations associated with the calculation of the sensitivities, that is, gradients of the behavior constraints, are reduced. Approximation to gradients of the behavior constraints that can be generated with small amount of numerical calculations is proposed. Structural optimization with these approximate sensitivities produced correct optimum solution. Approximate gradients performed well for different nonlinear programming methods, such as the sequence of unconstrained minimization technique, method of feasible directions, sequence of quadratic programming, and sequence of linear programming. Structural optimization with approximate gradients can reduce by one third the CPU time that would otherwise be required to solve the problem with explicit closed-form gradients. The proposed gradient approximation shows potential to reduce intensive computation that has been associated with traditional structural optimization.

  2. The Genetic Structure and History of Africans and African Americans

    PubMed Central

    Tishkoff, Sarah A.; Reed, Floyd A.; Friedlaender, Françoise R.; Ehret, Christopher; Ranciaro, Alessia; Froment, Alain; Hirbo, Jibril B.; Awomoyi, Agnes A.; Bodo, Jean-Marie; Doumbo, Ogobara; Ibrahim, Muntaser; Juma, Abdalla T.; Kotze, Maritha J.; Lema, Godfrey; Moore, Jason H.; Mortensen, Holly; Nyambo, Thomas B.; Omar, Sabah A.; Powell, Kweli; Pretorius, Gideon S.; Smith, Michael W.; Thera, Mahamadou A.; Wambebe, Charles; Weber, James L.; Williams, Scott M.

    2010-01-01

    Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies. PMID:19407144

  3. The landscape of recombination in African Americans.

    PubMed

    Hinch, Anjali G; Tandon, Arti; Patterson, Nick; Song, Yunli; Rohland, Nadin; Palmer, Cameron D; Chen, Gary K; Wang, Kai; Buxbaum, Sarah G; Akylbekova, Ermeg L; Aldrich, Melinda C; Ambrosone, Christine B; Amos, Christopher; Bandera, Elisa V; Berndt, Sonja I; Bernstein, Leslie; Blot, William J; Bock, Cathryn H; Boerwinkle, Eric; Cai, Qiuyin; Caporaso, Neil; Casey, Graham; Cupples, L Adrienne; Deming, Sandra L; Diver, W Ryan; Divers, Jasmin; Fornage, Myriam; Gillanders, Elizabeth M; Glessner, Joseph; Harris, Curtis C; Hu, Jennifer J; Ingles, Sue A; Isaacs, William; John, Esther M; Kao, W H Linda; Keating, Brendan; Kittles, Rick A; Kolonel, Laurence N; Larkin, Emma; Le Marchand, Loic; McNeill, Lorna H; Millikan, Robert C; Murphy, Adam; Musani, Solomon; Neslund-Dudas, Christine; Nyante, Sarah; Papanicolaou, George J; Press, Michael F; Psaty, Bruce M; Reiner, Alex P; Rich, Stephen S; Rodriguez-Gil, Jorge L; Rotter, Jerome I; Rybicki, Benjamin A; Schwartz, Ann G; Signorello, Lisa B; Spitz, Margaret; Strom, Sara S; Thun, Michael J; Tucker, Margaret A; Wang, Zhaoming; Wiencke, John K; Witte, John S; Wrensch, Margaret; Wu, Xifeng; Yamamura, Yuko; Zanetti, Krista A; Zheng, Wei; Ziegler, Regina G; Zhu, Xiaofeng; Redline, Susan; Hirschhorn, Joel N; Henderson, Brian E; Taylor, Herman A; Price, Alkes L; Hakonarson, Hakon; Chanock, Stephen J; Haiman, Christopher A; Wilson, James G; Reich, David; Myers, Simon R

    2011-08-11

    Recombination, together with mutation, gives rise to genetic variation in populations. Here we leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantly, and we identify about 2,500 recombination hotspots that are active in people of West African ancestry but nearly inactive in Europeans. The probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at PRDM9 (P value < 10(-245)). We identify a 17-base-pair DNA sequence motif that is enriched in these hotspots, and is an excellent match to the predicted binding target of PRDM9 alleles common in West Africans and rare in Europeans. Sites of this motif are predicted to be risk loci for disease-causing genomic rearrangements in individuals carrying these alleles. More generally, this map provides a resource for research in human genetic variation and evolution. PMID:21775986

  4. The landscape of recombination in African Americans

    PubMed Central

    Hinch, Anjali G.; Tandon, Arti; Patterson, Nick; Song, Yunli; Rohland, Nadin; Palmer, Cameron D.; Chen, Gary K.; Wang, Kai; Buxbaum, Sarah G.; Akylbekova, Meggie; Aldrich, Melinda C.; Ambrosone, Christine B.; Amos, Christopher; Bandera, Elisa V.; Berndt, Sonja I.; Bernstein, Leslie; Blot, William J.; Bock, Cathryn H.; Boerwinkle, Eric; Cai, Qiuyin; Caporaso, Neil; Casey, Graham; Cupples, L. Adrienne; Deming, Sandra L.; Diver, W. Ryan; Divers, Jasmin; Fornage, Myriam; Gillanders, Elizabeth M.; Glessner, Joseph; Harris, Curtis C.; Hu, Jennifer J.; Ingles, Sue A.; Isaacs, Williams; John, Esther M.; Kao, W. H. Linda; Keating, Brendan; Kittles, Rick A.; Kolonel, Laurence N.; Larkin, Emma; Le Marchand, Loic; McNeill, Lorna H.; Millikan, Robert C.; Murphy, Adam; Musani, Solomon; Neslund-Dudas, Christine; Nyante, Sarah; Papanicolaou, George J.; Press, Michael F.; Psaty, Bruce M.; Reiner, Alex P.; Rich, Stephen S.; Rodriguez-Gil, Jorge L.; Rotter, Jerome I.; Rybicki, Benjamin A.; Schwartz, Ann G.; Signorello, Lisa B.; Spitz, Margaret; Strom, Sara S.; Thun, Michael J.; Tucker, Margaret A.; Wang, Zhaoming; Wiencke, John K.; Witte, John S.; Wrensch, Margaret; Wu, Xifeng; Yamamura, Yuko; Zanetti, Krista A.; Zheng, Wei; Ziegler, Regina G.; Zhu, Xiaofeng; Redline, Susan; Hirschhorn, Joel N.; Henderson, Brian E.; Taylor, Herman A.; Price, Alkes L.; Hakonarson, Hakon; Chanock, Stephen J.; Haiman, Christopher A.; Wilson, James G.; Reich, David; Myers, Simon R.

    2011-01-01

    Recombination, together with mutation, is the ultimate source of genetic variation in populations. We leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing-over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantly, and we identify about 2,500 recombination hotspots that are active in people of West African ancestry but nearly inactive in Europeans. The probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at PRDM9 (P<10−245). We identify a 17 base pair DNA sequence motif that is enriched in these hotspots, and is an excellent match to the predicted binding target of African-enriched alleles of PRDM9. PMID:21775986

  5. Role of inertial instability in the West African monsoon jump

    NASA Astrophysics Data System (ADS)

    Cook, Kerry H.

    2015-04-01

    The West African monsoon jump is a sudden shift in the latitude of the West African precipitation maximum from the Guinean coast near 4°N into Sahel near 12°N in late June or early July. An examination of reanalyses and observations indicates that the Sahel rainy season develops smoothly and the monsoon jump occurs because of an abrupt decrease in Guinean coast rainfall. We show that this abrupt end of the coastal rainy season occurs when inertial instability develops over the region, 1 month later than it develops in the vicinity of the marine Atlantic Intertropical Convergence Zone. The reason for this delay is the presence of the African easterly jet, which places strong negative meridional zonal wind gradients over the coast to preserve the inertially stable environment. When the African easterly jet moves farther north due to the seasonal solar forcing, these gradients weaken and then reverse to satisfy the threshold condition for inertial instability; the rapid end of the Guinean coast rainy season follows. The northward movement and intensity of the African easterly jet are controlled by the seasonal development of strong meridional land surface temperature gradients and are independent of the formation of the Atlantic cold tongue. This explanation for the West African monsoon jump relates the phenomenon to the shape and location of the African continent, including the low-latitude position of the Guinean coast and the large expanse of the continent to the north.

  6. Plea to African heads-of-state: join the fight.

    PubMed

    Tyson, R

    1997-10-01

    Uganda's president, Yoweri Museveni, is the only African head-of-state who has led an all-out, extended campaign against AIDS, and Uganda is the only African country to realize a decline in HIV rates since the epidemic began spreading across central and southern Africa in the 1980s. While South Africa's President Nelson Mandela has spoken about AIDS in international forums, his country's programs against AIDS are in disarray. Rather than adopt a position of leadership against HIV/AIDS, African leaders have most often tried to cover up or ignore the AIDS threat. Zimbabwe and Nigeria are briefly discussed as examples. More than 100 delegates attended the HIV/AIDS workshop at the fourth African-African American Summit held in Harare, July 1997. After listening for 2 days to medical experts describe how the epidemic is destroying African economies and social structures, task force members called upon leaders of the 40 sub-Saharan African countries to acknowledge the threat of AIDS in their countries and to fight against the epidemic. PMID:12293006

  7. Fostering Healthy Lifestyles in the African American Population

    ERIC Educational Resources Information Center

    Murimi, Mary; Chrisman, Matthew S.; McAllister, Tiffany; McDonald, Olevia D.

    2015-01-01

    Approximately 8.3% of the U.S. population (25.8 million people) is affected by type 2 diabetes. The burden of diabetes is disproportionately greater in the African American community. Compared with non-Hispanic Caucasian adults, the risk of diagnosed type 2 diabetes was 77% higher among non-Hispanic Blacks, who are 27% more likely to die of…

  8. Homies: Peer Mentoring among African-American Males.

    ERIC Educational Resources Information Center

    Braden, Warren R.

    Peer mentoring among African-American males (referred to as "homies") on the west side of Chicago was examined in an afrocentric ethnographic study. The study used three data collection methods: a survey (of respondents' definition of the word "mentor") administered at bus stops, elevated train stations, gyms, and libraries to approximately 100…

  9. Approximate Genealogies Under Genetic Hitchhiking

    PubMed Central

    Pfaffelhuber, P.; Haubold, B.; Wakolbinger, A.

    2006-01-01

    The rapid fixation of an advantageous allele leads to a reduction in linked neutral variation around the target of selection. The genealogy at a neutral locus in such a selective sweep can be simulated by first generating a random path of the advantageous allele's frequency and then a structured coalescent in this background. Usually the frequency path is approximated by a logistic growth curve. We discuss an alternative method that approximates the genealogy by a random binary splitting tree, a so-called Yule tree that does not require first constructing a frequency path. Compared to the coalescent in a logistic background, this method gives a slightly better approximation for identity by descent during the selective phase and a much better approximation for the number of lineages that stem from the founder of the selective sweep. In applications such as the approximation of the distribution of Tajima's D, the two approximation methods perform equally well. For relevant parameter ranges, the Yule approximation is faster. PMID:17182733

  10. Comparative endocrinology of testicular, adrenal and thyroid function in captive Asian and African elephant bulls.

    PubMed

    Brown, Janine L; Somerville, Malia; Riddle, Heidi S; Keele, Mike; Duer, Connie K; Freeman, Elizabeth W

    2007-04-01

    Concentrations of serum testosterone, cortisol, thyroxine (free and total T4), triiodothyronine (free and total T3) and thyroid stimulating hormone (TSH) were measured to assess adrenal and thyroid function as they relate to testicular activity and musth in captive elephants. Blood samples were collected approximately weekly from Asian (n=8) and African (n=12) bulls at seven facilities for periods of 4 months to 9.5 years. Age ranges at study onset were 8-50 years for Asian and 10-21 years for African elephants. Based on keeper logs, seven Asian and three African bulls exhibited behavioral and/or physical (temporal gland secretion, TGS, or urine dribbling, UD) signs of musth, which lasted 2.8+/-2.5 months in duration. Serum testosterone was elevated during musth, with concentrations often exceeding 100 ng/ml. Patterns of testosterone secretion and musth varied among bulls with no evidence of seasonality (P>0.05). Only three bulls at one facility exhibited classic, well-defined yearly musth cycles. Others exhibited more irregular cycles, with musth symptoms often occurring more than once a year. A number of bulls (1 Asian, 9 African) had consistently low testosterone (<10 ng/ml) and never exhibited significant TGS or UD. At facilities with multiple bulls (n=3), testosterone concentrations were highest in the oldest, most dominant male. There were positive correlations between testosterone and cortisol for six of seven Asian and all three African males that exhibited musth (range, r=0.23-0.52; P<0.05), but no significant correlations for bulls that did not (P>0.05). For the three bulls that exhibited yearly musth cycles, TSH was positively correlated (range, r=0.22-0.28; P<0.05) and thyroid hormones (T3, T4) were negatively correlated (range, r=-0.25 to -0.47; P<0.05) to testosterone secretion. In the remaining bulls, there were no clear relationships between thyroid activity and musth status. Overall mean testosterone and cortisol concentrations increased with age

  11. Mothers’ Parenting and Child Sex Differences in Behavior Problems among African American Preschoolers

    PubMed Central

    Barnett, Melissa A.; Scaramella, Laura V.

    2014-01-01

    Sex differences in rates of behavior problems, including internalizing and externalizing problems, begin to emerge during early childhood. These sex differences may occur because mothers parent their sons and daughters differently, or because the impact of parenting on behavior problems is different for boys and girls. This study examines whether associations between observations of mothers’ positive and negative parenting and children’s externalizing and internalizing behaviors vary as a function of child sex. The sample consists of 137 African American, low-income families with one sibling approximately two-years-old and the closest aged older sibling who is approximately four-years-old. Results from fixed-effects within-family models indicate clear sex differences regardless of child age. Mothers were observed to use less positive parenting with sons than with daughters. Higher levels of observed negative parenting were linked to more externalizing behaviors for boys, while lower levels of positive parenting were linked to more externalizing behaviors for girls. No child sex differences emerged regarding associations between observed positive and negative parenting and internalizing behaviors. PMID:23937420

  12. The Other African Americans.

    ERIC Educational Resources Information Center

    Matory, J. Lorand

    Black North America is ethnically and culturally diverse. It contains many groups who do not call themselves or have not always called themselves "Negro,""Black,""African-American," and so forth, such as Louisiana Creoles of color and many of the Indian tribes east of the Mississippi. There are also numerous North American ethnic groups of African…

  13. African American rhinoplasty.

    PubMed

    Boyette, Jennings R; Stucker, Fred J

    2014-08-01

    Rhinoplasty in patients of African descent requires a patient-specific approach, because the goals and ideal proportions differ from the white nose. This article discusses approaches to surgical correction of common anatomic variations. In addition, common pitfalls are outlined. PMID:25049123

  14. Elective: African Literature.

    ERIC Educational Resources Information Center

    Jenkins, Kenneth V.

    The make-up of a course in African literature for high school students is discussed. It is pointed out that the course can be constructed on already familiar lines. High school students will be able to describe clearly, for example, the relationship between environment and character or the dilemma of characters caught between traditional values…

  15. Experiences of racist events are associated with negative health consequences for African American women.

    PubMed Central

    Kwate, Naa Oyo A.; Valdimarsdottir, Heiddis B.; Guevarra, Josephine S.; Bovbjerg, Dana H.

    2003-01-01

    This study investigated whether experiences of racist events were related to psychological distress, negative health behaviors, and health problems. Participants were 71 African American women (mean age 44.4) who were recruited from an urban cancer-screening clinic as part of a larger longitudinal study on familial risk of breast cancer. Participants completed three study assessments, approximately one month apart, and data were collected via self-report. Correlational analyses revealed that past year and lifetime racism were both related to psychological distress. Among smokers and drinkers, past year racism was positively correlated with number of cigarettes and drinks consumed. Lifetime racism was negatively related to perceived health, and positively related to lifetime history of physical disease and frequency of recent common colds. Analyses using a general linear model revealed that these relationships were largely unaccounted for by other variables. In addition, demographic variables such as income and education were not related to experiences of racism. The results suggest that racism can be detrimental to African American's well being and should be investigated in health disparities research. PMID:12856911

  16. Mathematical algorithms for approximate reasoning

    NASA Technical Reports Server (NTRS)

    Murphy, John H.; Chay, Seung C.; Downs, Mary M.

    1988-01-01

    Most state of the art expert system environments contain a single and often ad hoc strategy for approximate reasoning. Some environments provide facilities to program the approximate reasoning algorithms. However, the next generation of expert systems should have an environment which contain a choice of several mathematical algorithms for approximate reasoning. To meet the need for validatable and verifiable coding, the expert system environment must no longer depend upon ad hoc reasoning techniques but instead must include mathematically rigorous techniques for approximate reasoning. Popular approximate reasoning techniques are reviewed, including: certainty factors, belief measures, Bayesian probabilities, fuzzy logic, and Shafer-Dempster techniques for reasoning. A group of mathematically rigorous algorithms for approximate reasoning are focused on that could form the basis of a next generation expert system environment. These algorithms are based upon the axioms of set theory and probability theory. To separate these algorithms for approximate reasoning various conditions of mutual exclusivity and independence are imposed upon the assertions. Approximate reasoning algorithms presented include: reasoning with statistically independent assertions, reasoning with mutually exclusive assertions, reasoning with assertions that exhibit minimum overlay within the state space, reasoning with assertions that exhibit maximum overlay within the state space (i.e. fuzzy logic), pessimistic reasoning (i.e. worst case analysis), optimistic reasoning (i.e. best case analysis), and reasoning with assertions with absolutely no knowledge of the possible dependency among the assertions. A robust environment for expert system construction should include the two modes of inference: modus ponens and modus tollens. Modus ponens inference is based upon reasoning towards the conclusion in a statement of logical implication, whereas modus tollens inference is based upon reasoning away

  17. Exponential approximations in optimal design

    NASA Technical Reports Server (NTRS)

    Belegundu, A. D.; Rajan, S. D.; Rajgopal, J.

    1990-01-01

    One-point and two-point exponential functions have been developed and proved to be very effective approximations of structural response. The exponential has been compared to the linear, reciprocal and quadratic fit methods. Four test problems in structural analysis have been selected. The use of such approximations is attractive in structural optimization to reduce the numbers of exact analyses which involve computationally expensive finite element analysis.

  18. Approximate factorization with source terms

    NASA Technical Reports Server (NTRS)

    Shih, T. I.-P.; Chyu, W. J.

    1991-01-01

    A comparative evaluation is made of three methodologies with a view to that which offers the best approximate factorization error. While two of these methods are found to lead to more efficient algorithms in cases where factors which do not contain source terms can be diagonalized, the third method used generates the lowest approximate factorization error. This method may be preferred when the norms of source terms are large, and transient solutions are of interest.

  19. African Ancestry Is Associated with Asthma Risk in African Americans

    PubMed Central

    Pino-Yanes, María; Wade, Michael S.; Pérez-Méndez, Lina; Kittles, Rick A.; Wang, Deli; Papaiahgari, Srinivas; Ford, Jean G.; Kumar, Rajesh; Garcia, Joe G. N.

    2012-01-01

    Background Asthma is a common complex condition with clear racial and ethnic differences in both prevalence and severity. Asthma consultation rates, mortality, and severe symptoms are greatly increased in African descent populations of developed countries. African ancestry has been associated with asthma, total serum IgE and lower pulmonary function in African-admixed populations. To replicate previous findings, here we aimed to examine whether African ancestry was associated with asthma susceptibility in African Americans. In addition, we examined for the first time whether African ancestry was associated with asthma exacerbations. Methodology/Principal Findings After filtering for self-reported ancestry and genotype data quality, samples from 1,117 self-reported African-American individuals from New York and Baltimore (394 cases, 481 controls), and Chicago (321 cases followed for asthma exacerbations) were analyzed. Genetic ancestry was estimated based on ancestry informative markers (AIMs) selected for being highly divergent among European and West African populations (95 AIMs for New York and Baltimore, and 66 independent AIMs for Chicago). Among case-control samples, the mean African ancestry was significantly higher in asthmatics than in non-asthmatics (82.0±14.0% vs. 77.8±18.1%, mean difference 4.2% [95% confidence interval (CI):2.0–6.4], p<0.0001). This association remained significant after adjusting for potential confounders (odds ratio: 4.55, 95% CI: 1.69–12.29, p = 0.003). African ancestry failed to show an association with asthma exacerbations (p = 0.965) using a model based on longitudinal data of the number of exacerbations followed over 1.5 years. Conclusions/Significance These data replicate previous findings indicating that African ancestry constitutes a risk factor for asthma and suggest that elevated asthma rates in African Americans can be partially attributed to African genetic ancestry. PMID:22235241

  20. Approximating random quantum optimization problems

    NASA Astrophysics Data System (ADS)

    Hsu, B.; Laumann, C. R.; Läuchli, A. M.; Moessner, R.; Sondhi, S. L.

    2013-06-01

    We report a cluster of results regarding the difficulty of finding approximate ground states to typical instances of the quantum satisfiability problem k-body quantum satisfiability (k-QSAT) on large random graphs. As an approximation strategy, we optimize the solution space over “classical” product states, which in turn introduces a novel autonomous classical optimization problem, PSAT, over a space of continuous degrees of freedom rather than discrete bits. Our central results are (i) the derivation of a set of bounds and approximations in various limits of the problem, several of which we believe may be amenable to a rigorous treatment; (ii) a demonstration that an approximation based on a greedy algorithm borrowed from the study of frustrated magnetism performs well over a wide range in parameter space, and its performance reflects the structure of the solution space of random k-QSAT. Simulated annealing exhibits metastability in similar “hard” regions of parameter space; and (iii) a generalization of belief propagation algorithms introduced for classical problems to the case of continuous spins. This yields both approximate solutions, as well as insights into the free energy “landscape” of the approximation problem, including a so-called dynamical transition near the satisfiability threshold. Taken together, these results allow us to elucidate the phase diagram of random k-QSAT in a two-dimensional energy-density-clause-density space.

  1. Phylogeny of African cichlid fishes as revealed by molecular markers.

    PubMed

    Mayer, W E; Tichy, H; Klein, J

    1998-06-01

    The species flocks of cichlid fish in the three great East African Lakes, Victoria, Malawi, and Tanganyika, have arisen in each lake by explosive adaptive radiation. Various questions concerning their phylogeny have not yet been answered. In particular, the identity of the ancestral founder species and the monophyletic origin of the haplochromine cichlids from the East African lakes have not been established conclusively. In the present study, we used the anonymous nuclear DNA marker DXTU1 as a step towards answering these questions. A 280 bp-fragment of the DXTU1 locus was amplified by the polymerase chain reaction from East African lacustrine species, the East African riverine cichlid species Haplochromis bloyeti, H. burtoni and H. sparsidens, and other African cichlids. Sequencing revealed several indels and substitutions that were used as cladistically informative markers to support a phylogenetic tree constructed by the neighbor-joining method. The topology, although not supported by high bootstrap values, corresponds well to the geographical distribution and previous classification of the cichlids. Markers could be defined that: (i) differentiate East African from West African cichlids; (ii) distinguish the riverine and Lake Victoria/Malawi haplochromines from Lake Tanganyika cichlids; and (iii) indicate the existence of a monophyletic Lake Victoria cichlid superflock which includes haplochromines from satellite lakes and East African rivers. In order to resolve further the relationship of East African riverine and lacustrine species, mtDNA cytochrome b and control region segments were sequenced. The mtDNA-based trees support the notion of the monophyly of the Lake Victoria superflock but are ambiguous with respect to the phylogenetic position of the Lake Malawi flock. PMID:9675872

  2. The Role of the Black Church, the Barbershop/Beauty Salon, and Digital Communication to Support African American Persons Living with HIV/AIDS

    ERIC Educational Resources Information Center

    Pillay, Yegan

    2011-01-01

    The Centers for Disease Control and Prevention (2010) reports that approximately 1 million people in the United States are living with HIV. African Americans comprise 12% of the population yet account for approximately 46% of the people living with HIV. The rising prevalence rate among African Americans is an anomaly given that the prevalence rate…

  3. North African vegetation-precipitation feedback in early and mid-Holocene climate simulations with CCSM3-DGVM

    NASA Astrophysics Data System (ADS)

    Rachmayani, R.; Prange, M.; Schulz, M.

    2015-02-01

    The present study analyses the sign, strength, and working mechanism of the vegetation-precipitation feedback over North Africa in middle (6 ka BP) and early Holocene (9 ka BP) simulations using the comprehensive coupled climate-vegetation model CCSM3-DGVM (Community Climate System Model version 3 and a dynamic global vegetation model). The coupled model simulates enhanced summer rainfall and a northward migration of the West African monsoon trough along with an expansion of the vegetation cover for the early and middle Holocene compared to the pre-industrial period. It is shown that dynamic vegetation enhances the orbitally triggered summer precipitation anomaly by approximately 20% in the Sahara-Sahel region (10-25° N, 20° W-30° E) in both the early and mid-Holocene experiments compared to their fixed-vegetation counterparts. The primary vegetation-rainfall feedback identified here operates through surface latent heat flux anomalies by canopy evaporation and transpiration and their effect on the mid-tropospheric African easterly jet, whereas the effects of vegetation changes on surface albedo and local water recycling play a negligible role. Even though CCSM3-DGVM simulates a positive vegetation-precipitation feedback in the North African region, this feedback is not strong enough to produce multiple equilibrium climate-ecosystem states on a regional scale.

  4. North African vegetation-precipitation feedback in early and mid-Holocene climate simulations with CCSM3-DGVM

    NASA Astrophysics Data System (ADS)

    Rachmayani, R.; Prange, M.; Schulz, M.

    2014-05-01

    The present study analyses the sign, strength and working mechanism of the vegetation-precipitation feedback over North Africa in middle (6 ka BP) and early Holocene (9 ka BP) simulations using the comprehensive coupled climate-vegetation model CCSM3-DGVM. The coupled model simulates enhanced summer rainfall and a northward migration of the West African monsoon trough along with an expansion of the vegetation cover for the early and middle Holocene compared to pre-industrial. It is shown that dynamic vegetation enhances the orbitally triggered summer precipitation anomaly by approximately 20% in the Sahara/Sahel region (10° N-25° N, 20° W-30° E) in both the early and mid-Holocene experiments compared to their fixed-vegetation counterparts. The primary vegetation-rainfall feedback identified here operates through surface latent heat flux anomalies by canopy evaporation and transpiration and their effect on the mid-tropospheric African Easterly Jet, whereas the effects of vegetation changes on surface albedo and local water recycling play a negligible role. Even though CCSM3-DGVM simulates a positive vegetation-precipitation feedback in the North African region, this feedback is not strong enough to produce multiple equilibrium climate-ecosystem states on a regional scale.

  5. Wavelet Sparse Approximate Inverse Preconditioners

    NASA Technical Reports Server (NTRS)

    Chan, Tony F.; Tang, W.-P.; Wan, W. L.

    1996-01-01

    There is an increasing interest in using sparse approximate inverses as preconditioners for Krylov subspace iterative methods. Recent studies of Grote and Huckle and Chow and Saad also show that sparse approximate inverse preconditioner can be effective for a variety of matrices, e.g. Harwell-Boeing collections. Nonetheless a drawback is that it requires rapid decay of the inverse entries so that sparse approximate inverse is possible. However, for the class of matrices that, come from elliptic PDE problems, this assumption may not necessarily hold. Our main idea is to look for a basis, other than the standard one, such that a sparse representation of the inverse is feasible. A crucial observation is that the kind of matrices we are interested in typically have a piecewise smooth inverse. We exploit this fact, by applying wavelet techniques to construct a better sparse approximate inverse in the wavelet basis. We shall justify theoretically and numerically that our approach is effective for matrices with smooth inverse. We emphasize that in this paper we have only presented the idea of wavelet approximate inverses and demonstrated its potential but have not yet developed a highly refined and efficient algorithm.

  6. Approximate entropy of network parameters.

    PubMed

    West, James; Lacasa, Lucas; Severini, Simone; Teschendorff, Andrew

    2012-04-01

    We study the notion of approximate entropy within the framework of network theory. Approximate entropy is an uncertainty measure originally proposed in the context of dynamical systems and time series. We first define a purely structural entropy obtained by computing the approximate entropy of the so-called slide sequence. This is a surrogate of the degree sequence and it is suggested by the frequency partition of a graph. We examine this quantity for standard scale-free and Erdös-Rényi networks. By using classical results of Pincus, we show that our entropy measure often converges with network size to a certain binary Shannon entropy. As a second step, with specific attention to networks generated by dynamical processes, we investigate approximate entropy of horizontal visibility graphs. Visibility graphs allow us to naturally associate with a network the notion of temporal correlations, therefore providing the measure a dynamical garment. We show that approximate entropy distinguishes visibility graphs generated by processes with different complexity. The result probes to a greater extent these networks for the study of dynamical systems. Applications to certain biological data arising in cancer genomics are finally considered in the light of both approaches. PMID:22680542

  7. Approximate entropy of network parameters

    NASA Astrophysics Data System (ADS)

    West, James; Lacasa, Lucas; Severini, Simone; Teschendorff, Andrew

    2012-04-01

    We study the notion of approximate entropy within the framework of network theory. Approximate entropy is an uncertainty measure originally proposed in the context of dynamical systems and time series. We first define a purely structural entropy obtained by computing the approximate entropy of the so-called slide sequence. This is a surrogate of the degree sequence and it is suggested by the frequency partition of a graph. We examine this quantity for standard scale-free and Erdös-Rényi networks. By using classical results of Pincus, we show that our entropy measure often converges with network size to a certain binary Shannon entropy. As a second step, with specific attention to networks generated by dynamical processes, we investigate approximate entropy of horizontal visibility graphs. Visibility graphs allow us to naturally associate with a network the notion of temporal correlations, therefore providing the measure a dynamical garment. We show that approximate entropy distinguishes visibility graphs generated by processes with different complexity. The result probes to a greater extent these networks for the study of dynamical systems. Applications to certain biological data arising in cancer genomics are finally considered in the light of both approaches.

  8. Relativistic regular approximations revisited: An infinite-order relativistic approximation

    SciTech Connect

    Dyall, K.G.; van Lenthe, E.

    1999-07-01

    The concept of the regular approximation is presented as the neglect of the energy dependence of the exact Foldy{endash}Wouthuysen transformation of the Dirac Hamiltonian. Expansion of the normalization terms leads immediately to the zeroth-order regular approximation (ZORA) and first-order regular approximation (FORA) Hamiltonians as the zeroth- and first-order terms of the expansion. The expansion may be taken to infinite order by using an un-normalized Foldy{endash}Wouthuysen transformation, which results in the ZORA Hamiltonian and a nonunit metric. This infinite-order regular approximation, IORA, has eigenvalues which differ from the Dirac eigenvalues by order E{sup 3}/c{sup 4} for a hydrogen-like system, which is a considerable improvement over the ZORA eigenvalues, and similar to the nonvariational FORA energies. A further perturbation analysis yields a third-order correction to the IORA energies, TIORA. Results are presented for several systems including the neutral U atom. The IORA eigenvalues for all but the 1s spinor of the neutral system are superior even to the scaled ZORA energies, which are exact for the hydrogenic system. The third-order correction reduces the IORA error for the inner orbitals to a very small fraction of the Dirac eigenvalue. {copyright} {ital 1999 American Institute of Physics.}

  9. The Strong African American Families Program: Translating Research into Prevention Programming

    ERIC Educational Resources Information Center

    Brody, Gene H.; Murry, Velma McBride; Gerrard, Meg; Gibbons, Frederick X.; Molgaard, Virginia; McNair, Lily; Brown, Anita C.; Wills, Thomas A.; Spoth, Richard L.; Luo, Zupei; Chen, Yi-fu; Neubaum-Carlan, Eileen

    2004-01-01

    A randomized prevention trial contrasted families who took part in the Strong African American Families Program (SAAF), a preventive intervention for rural African American mothers and their 11-year-olds, with control families. SAAF is based on a contextual model positing that regulated, communicative parenting causes changes in factors protecting…

  10. Understanding Parenting Stress among Young, Low-Income, African-American, First-Time Mothers

    ERIC Educational Resources Information Center

    Chang, Yiting; Fine, Mark A.; Ispa, Jean; Thornburg, Kathy R.; Sharp, Elizabeth; Wolfenstein, Miriam

    2004-01-01

    The purpose of this study was to test a theoretical model that examined the extent to which cognitive readiness to parent, perceived difficult child temperament, observed parenting behaviors, and positive coping styles predicted parenting stress among young, low-income, first-time, African-American mothers. One hundred and twenty African-American,…

  11. Academic and Career Trajectories of African American Males in San Bernardino

    ERIC Educational Resources Information Center

    Lyles, Lolita Laree

    2013-01-01

    A qualitative grounded theory approach is utilized to study the academic and career trajectories of twenty African American male collegiate students living in San Bernardino, California. There is limited research that explores the positive educational experiences of young adult African American males. Therefore, the aim of the present study is to…

  12. The Relationship between African American Middle School Students' Attitudes toward Reading and Their Reading Comprehension Level

    ERIC Educational Resources Information Center

    Harris, LeCharle Webb

    2009-01-01

    There are numerous strongly held views and myths about African American students in general and middle school students in particular. This study investigated widely held views about African American middle school students' attitudes toward reading and about how positive attitudes toward reading affect reading performances. In this study, four…

  13. An Examination of the Lived Experiences of Successful African American Men Attending a Historically Black University

    ERIC Educational Resources Information Center

    Powell, Clark R.

    2013-01-01

    This phenomenological research explored the lived experiences of successful African American men attending a Historically Black College and University (HBCU) in the Midwest. The guiding questions for the study were (a) What positive characteristics do successful African American men demonstrate at HBCUs that offset major problems, concerns, and…

  14. Racial Respect and Racial Socialization as Protective Factors for African American Male Youth

    ERIC Educational Resources Information Center

    DeGruy, Joy; Kjellstrand, Jean M.; Briggs, Harold E.; Brennan, Eileen M.

    2012-01-01

    African American adolescents must negotiate the transition to adulthood in a society that makes the achievement of positive cultural identity and self-respect difficult. Frequently, young men turn to violence in an attempt to achieve respect in their communities. This article explores factors that predict the use of violence among African American…

  15. In Their Own Words: Perceived Barriers to Achievement by African American and Latino High School Students

    ERIC Educational Resources Information Center

    Vega, Desireé; Moore, James L., III; Miranda, Antoinette H.

    2015-01-01

    Drawing on a larger study, this qualitative investigation explored the factors that African American and Latino high school students perceived as barriers to positive educational opportunities. Eighteen African American and Latino urban high school students comprised the sample. The findings indicated that perceived barriers to positive…

  16. Redefining Leadership: Examination of African American Women Serving as Presidents in Institutions of Higher Education

    ERIC Educational Resources Information Center

    Ausmer, Nicole M.

    2009-01-01

    There is an apparent dearth in the leadership literature of African American women when juxtaposed with race, gender and social class. This scarcity appears to be connected with the small percentage of African American women who hold the position of president in institutions of higher education. Additionally, recent reports have noted, that the…

  17. Leptin levels in the obese African parturient.

    PubMed

    Kafulafula, G; Moodley, J

    2001-05-01

    Prolactin, HCG and oestrogen are reported to have a role in regulating serum leptin levels and therefore adiposity in pregnancy. The aim of this study was to determine serum leptin levels during pregnancy in African women, and was conducted in the Antenatal Clinic, King Edward VIII Hospital, Durban, South Africa. Eighty-two obese and non-obese women were studied. Demographic details and anthropometric measurements were recorded, and serum leptin levels determined by radio-immunoassay in all women. Age, parity and gestational age showed a weak correlation with leptin levels. Weight (4=0.6); body mass index (r=0.5), and the circumference of midarm (r=0.4), waist (4-0.6, hip (5=0.5) and thigh correlated positively with leptin values. Serum leptin values in African pregnant women are not dissimilar to that of studies in other racial groups. PMID:12521847

  18. Understanding traditional African healing

    PubMed Central

    MOKGOBI, M.G.

    2015-01-01

    Traditional African healing has been in existence for many centuries yet many people still seem not to understand how it relates to God and religion/spirituality. Some people seem to believe that traditional healers worship the ancestors and not God. It is therefore the aim of this paper to clarify this relationship by discussing a chain of communication between the worshipers and the Almighty God. Other aspects of traditional healing namely types of traditional healers, training of traditional healers as well as the role of traditional healers in their communities are discussed. In conclusion, the services of traditional healers go far beyond the uses of herbs for physical illnesses. Traditional healers serve many roles which include but not limited to custodians of the traditional African religion and customs, educators about culture, counselors, social workers and psychologists. PMID:26594664

  19. Gadgets, approximation, and linear programming

    SciTech Connect

    Trevisan, L.; Sudan, M.; Sorkin, G.B.; Williamson, D.P.

    1996-12-31

    We present a linear-programming based method for finding {open_quotes}gadgets{close_quotes}, i.e., combinatorial structures reducing constraints of one optimization problems to constraints of another. A key step in this method is a simple observation which limits the search space to a finite one. Using this new method we present a number of new, computer-constructed gadgets for several different reductions. This method also answers a question posed by on how to prove the optimality of gadgets-we show how LP duality gives such proofs. The new gadgets improve hardness results for MAX CUT and MAX DICUT, showing that approximating these problems to within factors of 60/61 and 44/45 respectively is N P-hard. We also use the gadgets to obtain an improved approximation algorithm for MAX 3SAT which guarantees an approximation ratio of .801. This improves upon the previous best bound of .7704.

  20. Uncertainty relations for approximation and estimation

    NASA Astrophysics Data System (ADS)

    Lee, Jaeha; Tsutsui, Izumi

    2016-05-01

    We present a versatile inequality of uncertainty relations which are useful when one approximates an observable and/or estimates a physical parameter based on the measurement of another observable. It is shown that the optimal choice for proxy functions used for the approximation is given by Aharonov's weak value, which also determines the classical Fisher information in parameter estimation, turning our inequality into the genuine Cramér-Rao inequality. Since the standard form of the uncertainty relation arises as a special case of our inequality, and since the parameter estimation is available as well, our inequality can treat both the position-momentum and the time-energy relations in one framework albeit handled differently.

  1. Heat pipe transient response approximation

    NASA Astrophysics Data System (ADS)

    Reid, Robert S.

    2002-01-01

    A simple and concise routine that approximates the response of an alkali metal heat pipe to changes in evaporator heat transfer rate is described. This analytically based routine is compared with data from a cylindrical heat pipe with a crescent-annular wick that undergoes gradual (quasi-steady) transitions through the viscous and condenser boundary heat transfer limits. The sonic heat transfer limit can also be incorporated into this routine for heat pipes with more closely coupled condensers. The advantages and obvious limitations of this approach are discussed. For reference, a source code listing for the approximation appears at the end of this paper. .

  2. African horse sickness.

    PubMed

    Zientara, S; Weyer, C T; Lecollinet, S

    2015-08-01

    African horse sickness (AHS) is a devastating disease of equids caused by an arthropod-borne virus belonging to the Reoviridae family, genus Orbivirus. It is considered a major health threat for horses in endemic areas in sub-Saharan Africa. African horse sickness virus (AHSV) repeatedly caused large epizootics in the Mediterranean region (North Africa and southern Europe in particular) as a result of trade in infected equids. The unexpected emergence of a closely related virus, the bluetongue virus, in northern Europe in 2006 has raised fears about AHSV introduction into Europe, and more specifically into AHSV-free regions that have reported the presence of AHSV vectors, e.g. Culicoides midges. North African and European countries should be prepared to face AHSV incursions in the future, especially since two AHSV serotypes (serotypes 2 and 7) have recently spread northwards to western (e.g. Senegal, Nigeria, Gambia) and eastern Africa (Ethiopia), where historically only serotype 9 had been isolated. The authors review key elements of AHS epidemiology, surveillance and prophylaxis. PMID:26601437

  3. Gender Ratio Imbalance Effects on HIV Risk Behaviors in African American Women

    PubMed Central

    Newsome, Valerie; Airhihenbuwa, Collins O.

    2015-01-01

    Although literature suggests that African American women are no more likely to engage in risky sex than their White counterparts, they are more likely to have sex partners with higher HIV risk. Thus, it is not solely an individual’s behavior that determines their risk, but also the behavior of their partner and their position within a sexual network. For this reason, it is important to consider the dynamics of heterosexual relationships in the African American community. An important area of concern regarding African American heterosexual relationships is that of partner availability. A shortage of available African American men for potential partnerships exists and is reportedly due to poorer health and higher mortality rates. Some have argued that gender-ratio imbalance may be responsible for increased HIV vulnerability for African American women. This article reviews the literature on gender ratio imbalance and HIV risk in the African American community, and presents implications and suggestions for future research and intervention. PMID:23041754

  4. East African Rift Valley, Kenya

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This rare, cloud free view of the East African Rift Valley, Kenya (1.5N, 35.5E) shows a clear view of the Turkwell River Valley, an offshoot of the African REift System. The East African Rift is part of a vast plate fracture which extends from southern Turkey, through the Red Sea, East Africa and into Mozambique. Dark green patches of forests are seen along the rift margin and tea plantations occupy the cooler higher ground.

  5. Pythagorean Approximations and Continued Fractions

    ERIC Educational Resources Information Center

    Peralta, Javier

    2008-01-01

    In this article, we will show that the Pythagorean approximations of [the square root of] 2 coincide with those achieved in the 16th century by means of continued fractions. Assuming this fact and the known relation that connects the Fibonacci sequence with the golden section, we shall establish a procedure to obtain sequences of rational numbers…

  6. Chemical Laws, Idealization and Approximation

    NASA Astrophysics Data System (ADS)

    Tobin, Emma

    2013-07-01

    This paper examines the notion of laws in chemistry. Vihalemm ( Found Chem 5(1):7-22, 2003) argues that the laws of chemistry are fundamentally the same as the laws of physics they are all ceteris paribus laws which are true "in ideal conditions". In contrast, Scerri (2000) contends that the laws of chemistry are fundamentally different to the laws of physics, because they involve approximations. Christie ( Stud Hist Philos Sci 25:613-629, 1994) and Christie and Christie ( Of minds and molecules. Oxford University Press, New York, pp. 34-50, 2000) agree that the laws of chemistry are operationally different to the laws of physics, but claim that the distinction between exact and approximate laws is too simplistic to taxonomise them. Approximations in chemistry involve diverse kinds of activity and often what counts as a scientific law in chemistry is dictated by the context of its use in scientific practice. This paper addresses the question of what makes chemical laws distinctive independently of the separate question as to how they are related to the laws of physics. From an analysis of some candidate ceteris paribus laws in chemistry, this paper argues that there are two distinct kinds of ceteris paribus laws in chemistry; idealized and approximate chemical laws. Thus, while Christie ( Stud Hist Philos Sci 25:613-629, 1994) and Christie and Christie ( Of minds and molecules. Oxford University Press, New York, pp. 34--50, 2000) are correct to point out that the candidate generalisations in chemistry are diverse and heterogeneous, a distinction between idealizations and approximations can nevertheless be used to successfully taxonomise them.

  7. Advancing breast cancer survivorship among African-American women.

    PubMed

    Coughlin, Steven S; Yoo, Wonsuk; Whitehead, Mary S; Smith, Selina A

    2015-09-01

    Advances have occurred in breast cancer survivorship but, for many African-American women, challenges and gaps in relevant information remain. This article identifies opportunities to address disparities in breast cancer survival and quality of life, and thereby to increase breast cancer survivorship among African-American women. For breast cancer survivors, common side effects, lasting for long periods after cancer treatment, include fatigue, loss of strength, difficulty sleeping, and sexual dysfunction. For addressing physical and mental health concerns, a variety of interventions have been evaluated, including exercise and weight training, dietary interventions, yoga and mindfulness-based stress reduction, and support groups or group therapy. Obesity has been associated with breast cancer recurrence and poorer survival. Relative to white survivors, African-American breast cancer survivors are more likely to be obese and less likely to engage in physical activity, although exercise improves overall quality of life and cancer-related fatigue. Considerable information exists about the effectiveness of such interventions for alleviating distress and improving quality of life among breast cancer survivors, but few studies have focused specifically on African-American women with a breast cancer diagnosis. Studies have identified a number of personal factors that are associated with resilience, increased quality of life, and positive adaptation to a breast cancer diagnosis. There is a need for a better understanding of breast cancer survivorship among African-American women. Additional evaluations of interventions for improving the quality of life and survival of African-American breast cancer survivors are desirable. PMID:26303657

  8. A Teacher's Guide to African Narratives. Studies in African Literature.

    ERIC Educational Resources Information Center

    O'Brien, Sara Talis

    This guide is designed to help secondary school teachers include African literature in their classes. It furnishes English and social studies teachers with a foundation for teaching African literature by offering critical commentary on the texts themselves. A synthesis of anthropological and historical material is presented to help both teachers…

  9. Testing the frozen flow approximation

    NASA Technical Reports Server (NTRS)

    Lucchin, Francesco; Matarrese, Sabino; Melott, Adrian L.; Moscardini, Lauro

    1993-01-01

    We investigate the accuracy of the frozen-flow approximation (FFA), recently proposed by Matarrese, et al. (1992), for following the nonlinear evolution of cosmological density fluctuations under gravitational instability. We compare a number of statistics between results of the FFA and n-body simulations, including those used by Melott, Pellman & Shandarin (1993) to test the Zel'dovich approximation. The FFA performs reasonably well in a statistical sense, e.g. in reproducing the counts-in-cell distribution, at small scales, but it does poorly in the crosscorrelation with n-body which means it is generally not moving mass to the right place, especially in models with high small-scale power.

  10. Nursing Positions

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Nursing Positions KidsHealth > For Parents > Nursing Positions Print A ... and actually needs to feed. Getting Comfortable With Breastfeeding Nursing can be one of the most challenging ...

  11. Approximate Counting of Graphical Realizations

    PubMed Central

    2015-01-01

    In 1999 Kannan, Tetali and Vempala proposed a MCMC method to uniformly sample all possible realizations of a given graphical degree sequence and conjectured its rapidly mixing nature. Recently their conjecture was proved affirmative for regular graphs (by Cooper, Dyer and Greenhill, 2007), for regular directed graphs (by Greenhill, 2011) and for half-regular bipartite graphs (by Miklós, Erdős and Soukup, 2013). Several heuristics on counting the number of possible realizations exist (via sampling processes), and while they work well in practice, so far no approximation guarantees exist for such an approach. This paper is the first to develop a method for counting realizations with provable approximation guarantee. In fact, we solve a slightly more general problem; besides the graphical degree sequence a small set of forbidden edges is also given. We show that for the general problem (which contains the Greenhill problem and the Miklós, Erdős and Soukup problem as special cases) the derived MCMC process is rapidly mixing. Further, we show that this new problem is self-reducible therefore it provides a fully polynomial randomized approximation scheme (a.k.a. FPRAS) for counting of all realizations. PMID:26161994

  12. Computer Experiments for Function Approximations

    SciTech Connect

    Chang, A; Izmailov, I; Rizzo, S; Wynter, S; Alexandrov, O; Tong, C

    2007-10-15

    This research project falls in the domain of response surface methodology, which seeks cost-effective ways to accurately fit an approximate function to experimental data. Modeling and computer simulation are essential tools in modern science and engineering. A computer simulation can be viewed as a function that receives input from a given parameter space and produces an output. Running the simulation repeatedly amounts to an equivalent number of function evaluations, and for complex models, such function evaluations can be very time-consuming. It is then of paramount importance to intelligently choose a relatively small set of sample points in the parameter space at which to evaluate the given function, and then use this information to construct a surrogate function that is close to the original function and takes little time to evaluate. This study was divided into two parts. The first part consisted of comparing four sampling methods and two function approximation methods in terms of efficiency and accuracy for simple test functions. The sampling methods used were Monte Carlo, Quasi-Random LP{sub {tau}}, Maximin Latin Hypercubes, and Orthogonal-Array-Based Latin Hypercubes. The function approximation methods utilized were Multivariate Adaptive Regression Splines (MARS) and Support Vector Machines (SVM). The second part of the study concerned adaptive sampling methods with a focus on creating useful sets of sample points specifically for monotonic functions, functions with a single minimum and functions with a bounded first derivative.

  13. Approximate reasoning using terminological models

    NASA Technical Reports Server (NTRS)

    Yen, John; Vaidya, Nitin

    1992-01-01

    Term Subsumption Systems (TSS) form a knowledge-representation scheme in AI that can express the defining characteristics of concepts through a formal language that has a well-defined semantics and incorporates a reasoning mechanism that can deduce whether one concept subsumes another. However, TSS's have very limited ability to deal with the issue of uncertainty in knowledge bases. The objective of this research is to address issues in combining approximate reasoning with term subsumption systems. To do this, we have extended an existing AI architecture (CLASP) that is built on the top of a term subsumption system (LOOM). First, the assertional component of LOOM has been extended for asserting and representing uncertain propositions. Second, we have extended the pattern matcher of CLASP for plausible rule-based inferences. Third, an approximate reasoning model has been added to facilitate various kinds of approximate reasoning. And finally, the issue of inconsistency in truth values due to inheritance is addressed using justification of those values. This architecture enhances the reasoning capabilities of expert systems by providing support for reasoning under uncertainty using knowledge captured in TSS. Also, as definitional knowledge is explicit and separate from heuristic knowledge for plausible inferences, the maintainability of expert systems could be improved.

  14. Approximate Counting of Graphical Realizations.

    PubMed

    Erdős, Péter L; Kiss, Sándor Z; Miklós, István; Soukup, Lajos

    2015-01-01

    In 1999 Kannan, Tetali and Vempala proposed a MCMC method to uniformly sample all possible realizations of a given graphical degree sequence and conjectured its rapidly mixing nature. Recently their conjecture was proved affirmative for regular graphs (by Cooper, Dyer and Greenhill, 2007), for regular directed graphs (by Greenhill, 2011) and for half-regular bipartite graphs (by Miklós, Erdős and Soukup, 2013). Several heuristics on counting the number of possible realizations exist (via sampling processes), and while they work well in practice, so far no approximation guarantees exist for such an approach. This paper is the first to develop a method for counting realizations with provable approximation guarantee. In fact, we solve a slightly more general problem; besides the graphical degree sequence a small set of forbidden edges is also given. We show that for the general problem (which contains the Greenhill problem and the Miklós, Erdős and Soukup problem as special cases) the derived MCMC process is rapidly mixing. Further, we show that this new problem is self-reducible therefore it provides a fully polynomial randomized approximation scheme (a.k.a. FPRAS) for counting of all realizations. PMID:26161994

  15. Urinary CYP Eicosanoid Excretion Correlates with Glomerular Filtration in African-Americans with Chronic Kidney Disease

    PubMed Central

    Dreisbach, Albert W; Smith, Stanley V; Kyle, Patrick B; Ramaiah, Manjunath; Amenuke, Margaret; Garrett, Michael R; Lirette, Seth T; Griswold, Michael E; Roman, Richard J

    2015-01-01

    Previous studies have indicated that cytochrome P450 (CYP) metabolites of arachidonic acid (AA), i.e., 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs), play an important role in the regulation of renal tubular and vascular function. The present study for the first time profiled HETEs and epoxygenase derived dihydroxyeicosatetraenoic acid diHETEs levels in spot urines and plasma in 262 African American patients from the University of Mississippi Chronic Kidney Disease Clinic and 31 African American controls. Significant correlations in eGFR and urinary 20-HETE/creatinine and 19-HETE/ creatinine levels were observed. The eGFR increased by 17.47 [p=0.001] and 60.68 [(p=0.005] ml/min/ for each ng/mg increase in 20-HETE and 19-HETE levels, respectively. Similar significant positive associations were found between the other urinary eicosanoids and eGFR and also with 19-HETE/urine creatinine concentration and proteinuria. We found that approximately 80% of plasma HETEs and 30% diHETEs were glucuronidated and the fractional excretion of 20-HETE was less than 1%. These results suggest that there is a significant hepatic source of urinary 20-HETE glucuronide and EETs with extensive renal biotransformation to metabolites which may play a role in the pathogenesis of CKD. PMID:25151892

  16. The gendered character of the African petty bourgeoisie.

    PubMed

    Mcfadden, P

    1994-02-01

    An African feminist states her states her views on the conditions of women in Africa. Changes have occurred within the middle class, which are reflected in the Women's Movement and in relations between men and women. Women are taking much stronger positions and challenging the African male dominance. Men now speak with reservation about the interact with feminists. African men tend to marry down to women of lesser social and educational class, or to marry non-African women to avoid the issue of equality as Africans. The African middle class is now composed of a sufficient number of women in site of unequal gender relations. Men now ask women about gender issues, albeit for ulterior motives: to avoid feminist backlash in the presentation of papers, or to fulfill a donor requirement. An annoying Change is men's identification of themselves as feminists. The question is raised as to why men cannot think of another term to describe their inherited socialization as oppressors. This acquisition of the term "feminist" becomes just another appropriation to enhance their power or resources. Universal and free education has opened doors for women over the past 30 years. The women's fight against colonialism was a fight for women's opportunities. A disturbing trend is for women to argue for a return to "true" African traditions, when no one today would ever accept life as peasant women did 500 years ago. All African traditions are patriarchal. African feminist traditions need to be reclaimed and resurfaced from under the "layers of male defined and male reconstructed charades." A dangerous precedent is taking place in South Africa, since the International Monetary Fund (IMR) and the World Bank are preempting the opportunities gained by women through liberal state policies. Acceptance of IMF/World Bank terms means lost opportunity to education, to professions, and to economic resources gained in the post-independence era. IMF/World Bank policies are "racist, classiest, and

  17. Positive Psychology

    ERIC Educational Resources Information Center

    Peterson, Christopher

    2009-01-01

    Positive psychology is a deliberate correction to the focus of psychology on problems. Positive psychology does not deny the difficulties that people may experience but does suggest that sole attention to disorder leads to an incomplete view of the human condition. Positive psychologists concern themselves with four major topics: (1) positive…

  18. 1. ONTARIO MINE IS LOCATED ALONG FAR RIGHT ROADWAY APPROXIMATELY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. ONTARIO MINE IS LOCATED ALONG FAR RIGHT ROADWAY APPROXIMATELY 100 YARDS FROM CAMERA POSITION. TAILING PILE DOWN SLOPE AND WEST OF CAMERA POSITION IN ID-31-C-44. - Florida Mountain Mining Sites, Ontario Mine, Northwest side of Florida Mountain, Silver City, Owyhee County, ID

  19. Approximate neutral point of a subsonic canard aircraft

    NASA Technical Reports Server (NTRS)

    Phillips, J. D.

    1985-01-01

    An approximate formula is derived for the position of the neutral point in canard aircraft. This formula accounts for the aerodynamic interference between the wing (rear wing) and the canard (forward wing). Topics covered include determination of the canard downwash derivative, determination of the canard and wing liftslopes including the aerodynamic interference, and calculation of the neutral point position.

  20. Clinical Characteristics of Breast Cancers in African-American Women with Benign Breast Disease: A Comparison to the Surveillance, Epidemiology, and End Results Program

    PubMed Central

    Mitro, Susanna D.; Ali-Fehmi, Rouba; Bandyopadhyay, Sudeshna; Alosh, Baraa; Albashiti, Bassam; Radisky, Derek C.; Frost, Marlene H.; Degnim, Amy C.; Ruterbusch, Julie J.; Cote, Michele L.

    2014-01-01

    Benign breast disease (BBD) is a very common condition, diagnosed in approximately half of all American women throughout their lifecourse. White women with BBD are known to be at substantially increased risk of subsequent breast cancer; however, nothing is known about breast cancer characteristics that develop after a BBD diagnosis in African-American women. Here, we compared 109 breast cancers that developed in a population of African-American women with a history of BBD to 10,601 breast cancers that developed in a general population of African-American women whose cancers were recorded by the Metropolitan Detroit Cancer Surveillance System (MDCSS population). Demographic and clinical characteristics of the BBD population were compared to the MDCSS population, using chi-squared tests, Fisher's exact tests, t-tests, and Wilcoxon tests where appropriate. Kaplan–Meier curves and Cox regression models were used to examine survival. Women in the BBD population were diagnosed with lower grade (p = 0.02), earlier stage cancers (p = 0.003) that were more likely to be hormone receptor-positive (p = 0.03) compared to the general metropolitan Detroit African-American population. In situ cancers were more common among women in the BBD cohort (36.7%) compared to the MDCSS population (22.1%, p < 0.001). Overall, women in the BBD population were less likely to die from breast cancer after 10 years of follow-up (p = 0.05), but this association was not seen when analyses were limited to invasive breast cancers. These results suggest that breast cancers occurring after a BBD diagnosis may have more favorable clinical parameters, but the majority of cancers are still invasive, with survival rates similar to the general African-American population. PMID:25200244

  1. Reflections on Language Policy in African Countries with Portuguese as an Official Language.

    ERIC Educational Resources Information Center

    Vilela, Mario

    2002-01-01

    Examines the place of Portuguese in Portugal's former African Colonies. Characterizes the postcolonial position of Portuguese in Africa as a complex relationship between Portuguese as the official language and the other languages of these countries. (Author/VWL)

  2. African-American Sacred Music.

    ERIC Educational Resources Information Center

    Bailey, A. Peter

    1991-01-01

    The history of African-American sacred music is traced from the time of slavery to the present interest in gospel music. The religious music of African Americans is geared toward liberation themes. It is important that this music does not dilute its power through cross-over with other music forms. (SLD)

  3. Positional plagiocephaly

    PubMed Central

    Cummings, Carl

    2011-01-01

    Cranial asymmetry occurring as a result of forces that deform skull shape in the supine position is known as deformational plagiocephaly. The risk of plagiocephaly may be modified by positioning the baby on alternate days with the head to the right or the left side, and by increasing time spent in the prone position during awake periods. When deformational plagiocephaly is already present, physiotherapy (including positioning equivalent to the preventive positioning, and exercises as needed for torticollis and positional preference) has been shown to be superior to counselling about preventive positioning only. Helmet therapy (moulding therapy) to reduce skull asymmetry has some drawbacks: it is expensive, significantly inconvenient due to the long hours of use per day and associated with skin complications. There is evidence that helmet therapy may increase the initial rate of improvement of asymmetry, but there is no evidence that it improves the final outcome for patients with moderate or severe plagiocephaly. PMID:23024590

  4. Role Models and Psychosocial Outcomes among African American Adolescents.

    ERIC Educational Resources Information Center

    Bryant, Alison L.; Zimmerman, Marc A.

    2003-01-01

    Examined relationship of role models among African American ninth-graders to substance use, delinquency, academic engagement, and psychological well-being. Found that males without male role models and females identifying brothers as role models reported the most problem behavior. Adolescents with paternal role models had most positive school…

  5. Successes and Challenges in East African Conservation Education

    ERIC Educational Resources Information Center

    Johnson-Pynn, Julie S.; Johnson, Laura R.

    2005-01-01

    Environmental education (EE) programs that include service-learning components have great potential to positively impact East African youth, their communities, and their ecology. This exploratory study describes 2 programs in East Africa, The Jane Goodall Institute's Roots & Shoots (R&S) and Wildlife Clubs of Uganda (WCU). The authors studied…

  6. African American treatment advocacy funding available, May 14 deadline.

    PubMed

    1999-05-01

    Glaxo Wellcome will fund advocacy initiatives designed to link HIV-positive African Americans to HIV treatment programs. Any 501(c)3 organization in the United States can submit a proposal. The grants cannot be used to provide medications or medical treatment. Portions of the Request for Proposals describing the grant objectives, criteria for selection, and the application process are reprinted. PMID:11366460

  7. Human demographic history: refining the recent African origin model.

    PubMed

    Excoffier, Laurent

    2002-12-01

    Recent studies of large portions of the human genome support a recent origin of modern humans from an African stock after a bottleneck of moderate size followed by a range expansion out of Africa. Under this simple scenario, patterns of molecular diversity suggest that balancing selection could be more prevalent than positive selection in coding regions. PMID:12433581

  8. Biculturalism and Academic Achievement of African American High School Students

    ERIC Educational Resources Information Center

    Rust, Jonathan P.; Jackson, Margo A.; Ponterotto, Joseph G.; Blumberg, Fran C.

    2011-01-01

    Biculturalism was examined as a factor that may positively affect the academic achievement of African American high school students, beyond cultural identity and self-esteem. Hierarchical regression analyses determined that cultural identity and academic self-esteem were important factors for academic achievement, but not biculturalism.…

  9. Urban African American Males' Perceptions of School Counseling Services

    ERIC Educational Resources Information Center

    Owens, Delila; Simmons, Robert W., III; Bryant, Rhonda M.; Henfield, Malik

    2011-01-01

    Using a qualitative framework, researchers explored urban African American male students' perceptions of their school counselors and the ways to improve school counseling services. While participants reported positive feelings toward their school counselors, they identified specific services school counselors can offer them to optimize academic…

  10. African Unit. An Instructional Unit for Sixth Grade.

    ERIC Educational Resources Information Center

    Lewis, Elaine

    This teaching guide presents objectives, activities, pre and posttests, and handouts to help sixth grade classroom teachers as they develop and implement educational programs about Africa. The major purpose is to help students develop positive attitudes toward other cultures, particularly African cultures. Specific objectives are to help students…

  11. Balm in Gilead: Spiritual Dimensions in Counseling African American Women.

    ERIC Educational Resources Information Center

    Frame, Marsha Wiggins; Williams, Carmen Braun; Green, Evelyn L.

    1999-01-01

    Describes African American cultural and spiritual traditions that are the bedrock for therapeutic work with this population. States women who present for counseling with emotional themes of isolation, devaluation, internalized oppression, and low self-esteem and quest for positive racial identity are especially receptive to interventions that…

  12. Perinatal AIDS: Permanency Planning for the African-American Community.

    ERIC Educational Resources Information Center

    Taylor-Brown, Susan; And Others

    1992-01-01

    Conducted a retrospective chart review utilizing Norwood's model on the families of the 83 infants whose cord blood was positive for maternal HIV antibodies or who were congenitally infected with HIV. Discusses implications for permanency planning in the context of their impact on the African-American community. (KS)

  13. Strategies for Preventing Disproportionate Exclusions of African American Students

    ERIC Educational Resources Information Center

    Tobin, Tary J.; Vincent, Claudia G.

    2011-01-01

    The authors studied changes in disproportionate exclusion of African American students, compared with their White peers, in relation to implementation of Schoolwide Positive Behavior Support using data from 46 schools. They measured (a) exclusion through suspension and expulsion data collected with the Schoolwide Information System; (b) Schoolwide…

  14. Improved non-approximability results

    SciTech Connect

    Bellare, M.; Sudan, M.

    1994-12-31

    We indicate strong non-approximability factors for central problems: N{sup 1/4} for Max Clique; N{sup 1/10} for Chromatic Number; and 66/65 for Max 3SAT. Underlying the Max Clique result is a proof system in which the verifier examines only three {open_quotes}free bits{close_quotes} to attain an error of 1/2. Underlying the Chromatic Number result is a reduction from Max Clique which is more efficient than previous ones.

  15. Quantum tunneling beyond semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Banerjee, Rabin; Ranjan Majhi, Bibhas

    2008-06-01

    Hawking radiation as tunneling by Hamilton-Jacobi method beyond semiclassical approximation is analysed. We compute all quantum corrections in the single particle action revealing that these are proportional to the usual semiclassical contribution. We show that a simple choice of the proportionality constants reproduces the one loop back reaction effect in the spacetime, found by conformal field theory methods, which modifies the Hawking temperature of the black hole. Using the law of black hole mechanics we give the corrections to the Bekenstein-Hawking area law following from the modified Hawking temperature. Some examples are explicitly worked out.

  16. Fermion tunneling beyond semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Majhi, Bibhas Ranjan

    2009-02-01

    Applying the Hamilton-Jacobi method beyond the semiclassical approximation prescribed in R. Banerjee and B. R. Majhi, J. High Energy Phys.JHEPFG1029-8479 06 (2008) 09510.1088/1126-6708/2008/06/095 for the scalar particle, Hawking radiation as tunneling of the Dirac particle through an event horizon is analyzed. We show that, as before, all quantum corrections in the single particle action are proportional to the usual semiclassical contribution. We also compute the modifications to the Hawking temperature and Bekenstein-Hawking entropy for the Schwarzschild black hole. Finally, the coefficient of the logarithmic correction to entropy is shown to be related with the trace anomaly.

  17. Generalized Gradient Approximation Made Simple

    SciTech Connect

    Perdew, J.P.; Burke, K.; Ernzerhof, M.

    1996-10-01

    Generalized gradient approximations (GGA{close_quote}s) for the exchange-correlation energy improve upon the local spin density (LSD) description of atoms, molecules, and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental constants. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential. {copyright} {ital 1996 The American Physical Society.}

  18. Bioenergy and African transformation.

    PubMed

    Lynd, Lee R; Sow, Mariam; Chimphango, Annie Fa; Cortez, Luis Ab; Brito Cruz, Carlos H; Elmissiry, Mosad; Laser, Mark; Mayaki, Ibrahim A; Moraes, Marcia Afd; Nogueira, Luiz Ah; Wolfaardt, Gideon M; Woods, Jeremy; van Zyl, Willem H

    2015-01-01

    Among the world's continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures. PMID:25709714

  19. Use of permethrin as a miticide in the African hedgehog (Atelerix albiventris).

    PubMed

    Staley, E C; Staley, E E; Behr, M J

    1994-04-01

    The African hedgehog, Atelerix albiventris (also known as Erinaceous albiventris; 1,2) has recently undergone an increase in popularity as an exotic pet. This popularity (Beatrix Potter not withstanding) is due in part to the small size of the African hedgehog (adults are 4-6 in in length, weighing approximately 1 lb), its lack of hibernation or aestivation if reared under controlled light and temperature, and its general good nature and accommodation to handling. PMID:8197715

  20. Stifled voices: barriers to help-seeking behavior for South African childhood sexual assault survivors.

    PubMed

    Smith, Kimberly; Bryant-Davis, Thema; Tillman, Shaquita; Marks, Alison

    2010-05-01

    In South Africa, females under the age of 18 comprise approximately 40% of the rapes and other forms of sexual assault that occur. However, South African girls face multiple barriers to seeking help in the aftermath of sexual assault. This literature review provides an overview of childhood sexual assault in South African girls and addresses barriers to help-seeking behaviors. Risk factors as well as relevant sociocultural, economic, structural, and psychological perceptions regarding childhood sexual assault among South African girls are also discussed. Finally, clinical implications, culturally relevant psychotherapeutic techniques, and suggestions for future research are provided in an effort to reduce the negative mental health consequences for the victims. PMID:20509076

  1. Wavelet Approximation in Data Assimilation

    NASA Technical Reports Server (NTRS)

    Tangborn, Andrew; Atlas, Robert (Technical Monitor)

    2002-01-01

    Estimation of the state of the atmosphere with the Kalman filter remains a distant goal because of high computational cost of evolving the error covariance for both linear and nonlinear systems. Wavelet approximation is presented here as a possible solution that efficiently compresses both global and local covariance information. We demonstrate the compression characteristics on the the error correlation field from a global two-dimensional chemical constituent assimilation, and implement an adaptive wavelet approximation scheme on the assimilation of the one-dimensional Burger's equation. In the former problem, we show that 99%, of the error correlation can be represented by just 3% of the wavelet coefficients, with good representation of localized features. In the Burger's equation assimilation, the discrete linearized equations (tangent linear model) and analysis covariance are projected onto a wavelet basis and truncated to just 6%, of the coefficients. A nearly optimal forecast is achieved and we show that errors due to truncation of the dynamics are no greater than the errors due to covariance truncation.

  2. Plasma Physics Approximations in Ares

    SciTech Connect

    Managan, R. A.

    2015-01-08

    Lee & More derived analytic forms for the transport properties of a plasma. Many hydro-codes use their formulae for electrical and thermal conductivity. The coefficients are complex functions of Fermi-Dirac integrals, Fn( μ/θ ), the chemical potential, μ or ζ = ln(1+e μ/θ ), and the temperature, θ = kT. Since these formulae are expensive to compute, rational function approximations were fit to them. Approximations are also used to find the chemical potential, either μ or ζ . The fits use ζ as the independent variable instead of μ/θ . New fits are provided for Aα (ζ ),Aβ (ζ ), ζ, f(ζ ) = (1 + e-μ/θ)F1/2(μ/θ), F1/2'/F1/2, Fcα, and Fcβ. In each case the relative error of the fit is minimized since the functions can vary by many orders of magnitude. The new fits are designed to exactly preserve the limiting values in the non-degenerate and highly degenerate limits or as ζ→ 0 or ∞. The original fits due to Lee & More and George Zimmerman are presented for comparison.

  3. Improved Approximability and Non-approximability Results for Graph Diameter Decreasing Problems

    NASA Astrophysics Data System (ADS)

    Bilò, Davide; Gualà, Luciano; Proietti, Guido

    In this paper we study two variants of the problem of adding edges to a graph so as to reduce the resulting diameter. More precisely, given a graph G = (V,E), and two positive integers D and B, the Minimum-Cardinality Bounded-Diameter Edge Addition (MCBD) problem is to find a minimum cardinality set F of edges to be added to G in such a way that the diameter of G + F is less than or equal to D, while the Bounded-Cardinality Minimum-Diameter Edge Addition (BCMD) problem is to find a set F of B edges to be added to G in such a way that the diameter of G + F is minimized. Both problems are well known to be NP-hard, as well as approximable within O(logn logD) and 4 (up to an additive term of 2), respectively. In this paper, we improve these long-standing approximation ratios to O(logn) and to 2 (up to an additive term of 2), respectively. As a consequence, we close, in an asymptotic sense, the gap on the approximability of the MCBD problem, which was known to be not approximable within c logn, for some constant c > 0, unless P=NP. Remarkably, as we further show in the paper, our approximation ratio remains asymptotically tight even if we allow for a solution whose diameter is optimal up to a multiplicative factor approaching 5/3. On the other hand, on the positive side, we show that at most twice of the minimal number of additional edges suffices to get at most twice of the required diameter.

  4. African refugee migration: a model and research agenda.

    PubMed

    Kayongo-male, D

    1989-01-01

    "This article elaborates upon the problems of the refugee crisis in Africa. With around 4 million refugees, heavily concentrated in particular African nations like Sudan and Somalia, the impacts on the host country can be severe. A model, dealing with the process of refugee migration, with particular reference to impacts on host countries, is developed. Negative impacts include military attacks on communities in the host country. One positive impact is the increase in the number of development-type projects which go beyond the mandate of the U.N. High Commissioner for Refugees. A tentative research agenda on African refugee migration is put forward." PMID:12316228

  5. Assimilation Differences among Africans in America.

    ERIC Educational Resources Information Center

    Dodoo, F. Nii-Amoo

    1997-01-01

    Census data (1990) indicate that male African immigrants earn more than their Caribbean-born counterparts or native-born African Americans, but controlling for relevant earnings-related endowments erases the African advantage and elevates Caribbean earnings above those of the other groups. Also, African (but not Caribbean) university degree…

  6. Successfully Educating Our African-American Students

    ERIC Educational Resources Information Center

    Moncree-Moffett, Kareem

    2013-01-01

    The purpose of this empirical study was to explore the lived experiences of African American retired female teachers who have prior experience with educating urban African American students in public schools. Also explored are the experiences of active African American female teachers of urban African American students and comparisons are…

  7. Interplay of approximate planning strategies.

    PubMed

    Huys, Quentin J M; Lally, Níall; Faulkner, Paul; Eshel, Neir; Seifritz, Erich; Gershman, Samuel J; Dayan, Peter; Roiser, Jonathan P

    2015-03-10

    Humans routinely formulate plans in domains so complex that even the most powerful computers are taxed. To do so, they seem to avail themselves of many strategies and heuristics that efficiently simplify, approximate, and hierarchically decompose hard tasks into simpler subtasks. Theoretical and cognitive research has revealed several such strategies; however, little is known about their establishment, interaction, and efficiency. Here, we use model-based behavioral analysis to provide a detailed examination of the performance of human subjects in a moderately deep planning task. We find that subjects exploit the structure of the domain to establish subgoals in a way that achieves a nearly maximal reduction in the cost of computing values of choices, but then combine partial searches with greedy local steps to solve subtasks, and maladaptively prune the decision trees of subtasks in a reflexive manner upon encountering salient losses. Subjects come idiosyncratically to favor particular sequences of actions to achieve subgoals, creating novel complex actions or "options." PMID:25675480

  8. Approximating metal-insulator transitions

    NASA Astrophysics Data System (ADS)

    Danieli, Carlo; Rayanov, Kristian; Pavlov, Boris; Martin, Gaven; Flach, Sergej

    2015-12-01

    We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step, the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate Metal-Insulator Transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges, which are at variance to the celebrated Aubry-André model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase, similar to the divergence of the localization length in the insulating phase.

  9. Strong shock implosion, approximate solution

    NASA Astrophysics Data System (ADS)

    Fujimoto, Y.; Mishkin, E. A.; Alejaldre, C.

    1983-01-01

    The self-similar, center-bound motion of a strong spherical, or cylindrical, shock wave moving through an ideal gas with a constant, γ= cp/ cv, is considered and a linearized, approximate solution is derived. An X, Y phase plane of the self-similar solution is defined and the representative curved of the system behind the shock front is replaced by a straight line connecting the mappings of the shock front with that of its tail. The reduced pressure P(ξ), density R(ξ) and velocity U1(ξ) are found in closed, quite accurate, form. Comparison with numerically obtained results, for γ= {5}/{3} and γ= {7}/{5}, is shown.

  10. Negro, Black, Black African, African Caribbean, African American or what? Labelling African origin populations in the health arena in the 21st century.

    PubMed

    Agyemang, Charles; Bhopal, Raj; Bruijnzeels, Marc

    2005-12-01

    Broad terms such as Black, African, or Black African are entrenched in scientific writings although there is considerable diversity within African descent populations and such terms may be both offensive and inaccurate. This paper outlines the heterogeneity within African populations, and discusses the strengths and limitations of the term Black and related labels from epidemiological and public health perspectives in Europe and the USA. This paper calls for debate on appropriate terminologies for African descent populations and concludes with the proposals that (1) describing the population under consideration is of paramount importance (2) the word African origin or simply African is an appropriate and necessary prefix for an ethnic label, for example, African Caribbean or African Kenyan or African Surinamese (3) documents should define the ethnic labels (4) the label Black should be phased out except when used in political contexts. PMID:16286485

  11. Approximate analytic solutions to the NPDD: Short exposure approximations

    NASA Astrophysics Data System (ADS)

    Close, Ciara E.; Sheridan, John T.

    2014-04-01

    There have been many attempts to accurately describe the photochemical processes that take places in photopolymer materials. As the models have become more accurate, solving them has become more numerically intensive and more 'opaque'. Recent models incorporate the major photochemical reactions taking place as well as the diffusion effects resulting from the photo-polymerisation process, and have accurately described these processes in a number of different materials. It is our aim to develop accessible mathematical expressions which provide physical insights and simple quantitative predictions of practical value to material designers and users. In this paper, starting with the Non-Local Photo-Polymerisation Driven Diffusion (NPDD) model coupled integro-differential equations, we first simplify these equations and validate the accuracy of the resulting approximate model. This new set of governing equations are then used to produce accurate analytic solutions (polynomials) describing the evolution of the monomer and polymer concentrations, and the grating refractive index modulation, in the case of short low intensity sinusoidal exposures. The physical significance of the results and their consequences for holographic data storage (HDS) are then discussed.

  12. Positive Psychotherapy

    ERIC Educational Resources Information Center

    Seligman, Martin E. P.; Rashid, Tayyab; Parks, Acacia C.

    2006-01-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported…

  13. Revisiting the diffusion approximation to estimate evolutionary rates of gene family diversification.

    PubMed

    Gjini, Erida; Haydon, Daniel T; David Barry, J; Cobbold, Christina A

    2014-01-21

    Genetic diversity in multigene families is shaped by multiple processes, including gene conversion and point mutation. Because multi-gene families are involved in crucial traits of organisms, quantifying the rates of their genetic diversification is important. With increasing availability of genomic data, there is a growing need for quantitative approaches that integrate the molecular evolution of gene families with their higher-scale function. In this study, we integrate a stochastic simulation framework with population genetics theory, namely the diffusion approximation, to investigate the dynamics of genetic diversification in a gene family. Duplicated genes can diverge and encode new functions as a result of point mutation, and become more similar through gene conversion. To model the evolution of pairwise identity in a multigene family, we first consider all conversion and mutation events in a discrete manner, keeping track of their details and times of occurrence; second we consider only the infinitesimal effect of these processes on pairwise identity accounting for random sampling of genes and positions. The purely stochastic approach is closer to biological reality and is based on many explicit parameters, such as conversion tract length and family size, but is more challenging analytically. The population genetics approach is an approximation accounting implicitly for point mutation and gene conversion, only in terms of per-site average probabilities. Comparison of these two approaches across a range of parameter combinations reveals that they are not entirely equivalent, but that for certain relevant regimes they do match. As an application of this modelling framework, we consider the distribution of nucleotide identity among VSG genes of African trypanosomes, representing the most prominent example of a multi-gene family mediating parasite antigenic variation and within-host immune evasion. PMID:24120993

  14. HIV Stigma and Social Support among African Americans

    PubMed Central

    Davis, E. Maxwell; Banks, Denedria; Bing, Eric G.

    2008-01-01

    Abstract HIV-related stigma and discrimination negatively impact African Americans living with HIV. Social support theory hypothesizes that social support can serve to protect individuals against the negative effects of stressors, such as discrimination, by leading them to interpret stressful occasions less negatively. This study sought to examine the relationship between perceived social support and perceived HIV stigma among HIV-positive African Americans. A cross-sectional convenience sample of 283 HIV-positive African Americans was recruited from three social service agencies. Bivariate and multivariate regressions were used to determine the variables predicting perceived HIV stigma. The study participants were found to have a wide variety of opinions concerning perceived HIV stigma. Of the three different sources of perceived social support examined (from family, friends and a “special person”), only perceived social support from friends was found to be related to perceived HIV stigma when controlling for the presence of other relevant factors. High perceived social support from friends was associated with less perceived HIV stigma. Other factors associated with low perceived HIV stigma included a lack of current symptoms of major depression, a longer time since HIV diagnosis and higher education. Information about the beneficial effects of perceived social support from friends and other factors can help to provide guidance to those working to decrease the negative impact of HIV stigma among HIV-positive African Americans. PMID:18373417

  15. African swine fever.

    PubMed

    Penrith, Mary-Louise

    2009-03-01

    African swine fever (ASF) is a devastating haemorrhagic fever of pigs that causes up to 100% mortality, for which there is no vaccine. It is caused by a unique DNA virus that is maintained in an ancient cycle between warthogs and argasid ticks, making it the only known DNA arbovirus. ASF has a high potential for transboundary spread, and has twice been transported from Africa to other continents--Europe and subsequently the Caribbean and Brazil (1957, 1959) and the Caucasus (2007). It is also a devastating constraint for pig production in Africa. Research at Onderstepoort Veterinary Institute has made and is making important contributions to knowledge of this disease, focusing on the cycle in warthogs and tampans and transmission from that cycle to domestic pigs, resistance to its effects in domestic pigs, and the molecular genetic characterisation and epidemiology of the virus. PMID:19967933

  16. The African Millennium Villages

    PubMed Central

    Sanchez, Pedro; Palm, Cheryl; Sachs, Jeffrey; Denning, Glenn; Flor, Rafael; Harawa, Rebbie; Jama, Bashir; Kiflemariam, Tsegazeab; Konecky, Bronwen; Kozar, Raffaela; Lelerai, Eliud; Malik, Alia; Modi, Vijay; Mutuo, Patrick; Niang, Amadou; Okoth, Herine; Place, Frank; Sachs, Sonia Ehrlich; Said, Amir; Siriri, David; Teklehaimanot, Awash; Wang, Karen; Wangila, Justine; Zamba, Colleen

    2007-01-01

    We describe the concept, strategy, and initial results of the Millennium Villages Project and implications regarding sustainability and scalability. Our underlying hypothesis is that the interacting crises of agriculture, health, and infrastructure in rural Africa can be overcome through targeted public-sector investments to raise rural productivity and, thereby, to increased private-sector saving and investments. This is carried out by empowering impoverished communities with science-based interventions. Seventy-eight Millennium Villages have been initiated in 12 sites in 10 African countries, each representing a major agroecological zone. In early results, the research villages in Kenya, Ethiopia, and Malawi have reduced malaria prevalence, met caloric requirements, generated crop surpluses, enabled school feeding programs, and provided cash earnings for farm families. PMID:17942701

  17. Improved approximations for control augmented structural synthesis

    NASA Technical Reports Server (NTRS)

    Thomas, H. L.; Schmit, L. A.

    1990-01-01

    A methodology for control-augmented structural synthesis is presented for structure-control systems which can be modeled as an assemblage of beam, truss, and nonstructural mass elements augmented by a noncollocated direct output feedback control system. Truss areas, beam cross sectional dimensions, nonstructural masses and rotary inertias, and controller position and velocity gains are treated simultaneously as design variables. The structural mass and a control-system performance index can be minimized simultaneously, with design constraints placed on static stresses and displacements, dynamic harmonic displacements and forces, structural frequencies, and closed-loop eigenvalues and damping ratios. Intermediate design-variable and response-quantity concepts are used to generate new approximations for displacements and actuator forces under harmonic dynamic loads and for system complex eigenvalues. This improves the overall efficiency of the procedure by reducing the number of complete analyses required for convergence. Numerical results which illustrate the effectiveness of the method are given.

  18. Her Story: A Qualitative Study of the Journey of the African American Woman Superintendent

    ERIC Educational Resources Information Center

    Jones, Jamill Ray

    2013-01-01

    The superintendency is the most male-dominated position in education (Alston, 2000; Brunner, 2000). Although statistical data reveal the disproportion between males and women in superintendent positions, the data also report a greater discrepancy in the number of African American women who have obtained superintendent positions. This qualitative…

  19. African easterly wave energetics on intraseasonal timescales

    NASA Astrophysics Data System (ADS)

    Alaka, Ghassan J., Jr.

    African easterly waves (AEWs) are synoptic-scale eddies that dominate North African weather in boreal summer. AEWs propagate westward with a maximum amplitude near 700 hPa and a period of 2.5-6-days. AEWs and associated perturbation kinetic energy (PKE) exhibit significant intraseasonal variability in tropical North Africa during boreal summer, which directly impacts local agriculture and tropical cyclogenesis. This study performs a comprehensive analysis of the 30-90-day variability of AEWs and associated energetics using both reanalysis data and model output. Specifically, the PKE and perturbation available potential energy (PAPE) budgets are used to understand the factors that contribute to PKE maxima in West Africa and the extent to which these surges of AEW activity are modulated by the Madden-Julian oscillation (MJO). The role of the MJO in the intraseasonal variability of AEWs is assessed by comparing PKE sources as a function of an MJO index and a local 30-90-day West African PKE index. Since East Africa is an initiation zone for AEW activity and is modulated by the MJO, the relationship between this region and West Africa is a primary focus in this study. The intraseasonal variability of AEW energetics is first investigated in reanalysis products. While reanalysis data depicts a similar evolution of 30-90-day PKE anomalies in both the MJO and a local PKE index, the MJO index describes only a small (yet still significant) fraction of the local 30-90-day variance. In boreal summers with more significant MJO days, the correlation between the two indices is higher. Baroclinic energy conversions are important for the initiation of 30-90-day West African PKE events east of Lake Chad. In West Africa, both barotropic and baroclinic energy conversions maintain positive PKE anomalies before they propagate into the Atlantic. The primary role of diabatic heating is to destroy PAPE in a negative feedback to baroclinic energy conversions in West Africa. More frequent

  20. "I am Not a Statistic": Identities of African American Males in Advanced Science Courses

    NASA Astrophysics Data System (ADS)

    Johnson, Diane Wynn

    The United States Bureau of Labor Statistics (2010) expects new industries to generate approximately 2.7 million jobs in science and technology by the year 2018, and there is concern as to whether there will be enough trained individuals to fill these positions. A tremendous resource remains untapped, African American students, especially African American males (National Science Foundation, 2009). Historically, African American males have been omitted from the so called science pipeline. Fewer African American males pursue a science discipline due, in part; to limiting factors they experience in school and at home (Ogbu, 2004). This is a case study of African American males who are enrolled in advanced science courses at a predominantly African American (84%) urban high school. Guided by expectancy-value theory (EVT) of achievement related results (Eccles, 2009; Eccles et al., 1983), twelve African American male students in two advanced science courses were observed in their science classrooms weekly, participated in an in-depth interview, developed a presentation to share with students enrolled in a tenth grade science course, responded to an open-ended identity questionnaire, and were surveyed about their perceptions of school. Additionally, the students' teachers were interviewed, and seven of the students' parents. The interview data analyses highlighted the important role of supportive parents (key socializers) who had high expectations for their sons and who pushed them academically. The students clearly attributed their enrollment in advanced science courses to their high regard for their science teachers, which included positive relationships, hands-on learning in class, and an inviting and encouraging learning environment. Additionally, other family members and coaches played important roles in these young men's lives. Students' PowerPoint(c) presentations to younger high school students on why they should take advanced science courses highlighted these

  1. Disordered eating in African American and Caucasian women: the role of ethnic identity.

    PubMed

    Shuttlesworth, Mary E; Zotter, Deanne

    2011-01-01

    The influential roles of culture and ethnic identity are frequently cited in developing disordered eating and body dissatisfaction, constituting both protective and risk factors. For African American women, strongly identifying with African American cultural beauty ideals may protect against disordered eating to lose weight, but may actually increase risk in development of disordered eating directed at weight gain, such as binge eating. This study compares African American and Caucasian women on disordered eating measures, positing that African American women show greater risk for binge eating due to the impact of ethnic identity on body dissatisfaction. Findings indicate low levels of ethnic identity represent a risk factor for African American women, increasing the likelihood of showing greater binge eating and bulimic pathology. In Caucasian women, high levels of ethnic identity constitute a risk factor, leading to higher levels of both binge eating and global eating pathology. Implications for prevention and treatment are discussed. PMID:22073427

  2. Horizontal and vertical dimensions of individualism-collectivism: a comparison of African Americans and European Americans.

    PubMed

    Komarraju, Meera; Cokley, Kevin O

    2008-10-01

    The current study examined ethnic differences in horizontal and vertical dimensions of individualism and collectivism among 96 African American and 149 European American college students. Participants completed the 32-item Singelis et al. (1995) Individualism/Collectivism Scale. Multivariate analyses of variance results yielded a main effect for ethnicity, with African Americans being significantly higher on horizontal individualism and European Americans being higher on horizontal collectivism and vertical individualism. A moderated multiple regression analysis indicated that ethnicity significantly moderated the relationship between individualism and collectivism. Individualism and collectivism were significantly and positively associated among African Americans, but not associated among European Americans. In addition, collectivism was related to grade point average for African Americans but not for European Americans. Contrary to the prevailing view of individualism-collectivism being unipolar, orthogonal dimensions, results provide support for individualism-collectivism to be considered as unipolar, related dimensions for African Americans. PMID:18954169

  3. Function approximation in inhibitory networks.

    PubMed

    Tripp, Bryan; Eliasmith, Chris

    2016-05-01

    In performance-optimized artificial neural networks, such as convolutional networks, each neuron makes excitatory connections with some of its targets and inhibitory connections with others. In contrast, physiological neurons are typically either excitatory or inhibitory, not both. This is a puzzle, because it seems to constrain computation, and because there are several counter-examples that suggest that it may not be a physiological necessity. Parisien et al. (2008) showed that any mixture of excitatory and inhibitory functional connections could be realized by a purely excitatory projection in parallel with a two-synapse projection through an inhibitory population. They showed that this works well with ratios of excitatory and inhibitory neurons that are realistic for the neocortex, suggesting that perhaps the cortex efficiently works around this apparent computational constraint. Extending this work, we show here that mixed excitatory and inhibitory functional connections can also be realized in networks that are dominated by inhibition, such as those of the basal ganglia. Further, we show that the function-approximation capacity of such connections is comparable to that of idealized mixed-weight connections. We also study whether such connections are viable in recurrent networks, and find that such recurrent networks can flexibly exhibit a wide range of dynamics. These results offer a new perspective on computation in the basal ganglia, and also perhaps on inhibitory networks within the cortex. PMID:26963256

  4. Interplay of approximate planning strategies

    PubMed Central

    Huys, Quentin J. M.; Lally, Níall; Faulkner, Paul; Eshel, Neir; Seifritz, Erich; Gershman, Samuel J.; Dayan, Peter; Roiser, Jonathan P.

    2015-01-01

    Humans routinely formulate plans in domains so complex that even the most powerful computers are taxed. To do so, they seem to avail themselves of many strategies and heuristics that efficiently simplify, approximate, and hierarchically decompose hard tasks into simpler subtasks. Theoretical and cognitive research has revealed several such strategies; however, little is known about their establishment, interaction, and efficiency. Here, we use model-based behavioral analysis to provide a detailed examination of the performance of human subjects in a moderately deep planning task. We find that subjects exploit the structure of the domain to establish subgoals in a way that achieves a nearly maximal reduction in the cost of computing values of choices, but then combine partial searches with greedy local steps to solve subtasks, and maladaptively prune the decision trees of subtasks in a reflexive manner upon encountering salient losses. Subjects come idiosyncratically to favor particular sequences of actions to achieve subgoals, creating novel complex actions or “options.” PMID:25675480

  5. Multidimensional stochastic approximation Monte Carlo.

    PubMed

    Zablotskiy, Sergey V; Ivanov, Victor A; Paul, Wolfgang

    2016-06-01

    Stochastic Approximation Monte Carlo (SAMC) has been established as a mathematically founded powerful flat-histogram Monte Carlo method, used to determine the density of states, g(E), of a model system. We show here how it can be generalized for the determination of multidimensional probability distributions (or equivalently densities of states) of macroscopic or mesoscopic variables defined on the space of microstates of a statistical mechanical system. This establishes this method as a systematic way for coarse graining a model system, or, in other words, for performing a renormalization group step on a model. We discuss the formulation of the Kadanoff block spin transformation and the coarse-graining procedure for polymer models in this language. We also apply it to a standard case in the literature of two-dimensional densities of states, where two competing energetic effects are present g(E_{1},E_{2}). We show when and why care has to be exercised when obtaining the microcanonical density of states g(E_{1}+E_{2}) from g(E_{1},E_{2}). PMID:27415383

  6. Decision analysis with approximate probabilities

    NASA Technical Reports Server (NTRS)

    Whalen, Thomas

    1992-01-01

    This paper concerns decisions under uncertainty in which the probabilities of the states of nature are only approximately known. Decision problems involving three states of nature are studied. This is due to the fact that some key issues do not arise in two-state problems, while probability spaces with more than three states of nature are essentially impossible to graph. The primary focus is on two levels of probabilistic information. In one level, the three probabilities are separately rounded to the nearest tenth. This can lead to sets of rounded probabilities which add up to 0.9, 1.0, or 1.1. In the other level, probabilities are rounded to the nearest tenth in such a way that the rounded probabilities are forced to sum to 1.0. For comparison, six additional levels of probabilistic information, previously analyzed, were also included in the present analysis. A simulation experiment compared four criteria for decisionmaking using linearly constrained probabilities (Maximin, Midpoint, Standard Laplace, and Extended Laplace) under the eight different levels of information about probability. The Extended Laplace criterion, which uses a second order maximum entropy principle, performed best overall.

  7. Multidimensional stochastic approximation Monte Carlo

    NASA Astrophysics Data System (ADS)

    Zablotskiy, Sergey V.; Ivanov, Victor A.; Paul, Wolfgang

    2016-06-01

    Stochastic Approximation Monte Carlo (SAMC) has been established as a mathematically founded powerful flat-histogram Monte Carlo method, used to determine the density of states, g (E ) , of a model system. We show here how it can be generalized for the determination of multidimensional probability distributions (or equivalently densities of states) of macroscopic or mesoscopic variables defined on the space of microstates of a statistical mechanical system. This establishes this method as a systematic way for coarse graining a model system, or, in other words, for performing a renormalization group step on a model. We discuss the formulation of the Kadanoff block spin transformation and the coarse-graining procedure for polymer models in this language. We also apply it to a standard case in the literature of two-dimensional densities of states, where two competing energetic effects are present g (E1,E2) . We show when and why care has to be exercised when obtaining the microcanonical density of states g (E1+E2) from g (E1,E2) .

  8. Nucleosome Positioning

    PubMed Central

    Nishida, Hiromi

    2012-01-01

    Nucleosome positioning is not only related to genomic DNA compaction but also to other biological functions. After the chromatin is digested by micrococcal nuclease, nucleosomal (nucleosome-bound) DNA fragments can be sequenced and mapped on the genomic DNA sequence. Due to the development of modern DNA sequencing technology, genome-wide nucleosome mapping has been performed in a wide range of eukaryotic species. Comparative analyses of the nucleosome positions have revealed that the nucleosome is more frequently formed in exonic than intronic regions, and that most of transcription start and translation (or transcription) end sites are located in nucleosome linker DNA regions, indicating that nucleosome positioning influences transcription initiation, transcription termination, and gene splicing. In addition, nucleosomal DNA contains guanine and cytosine (G + C)-rich sequences and a high level of cytosine methylation. Thus, the nucleosome positioning system has been conserved during eukaryotic evolution.

  9. Positive Proof.

    ERIC Educational Resources Information Center

    Auty, Geoffrey

    1988-01-01

    Presents experiments which show that in electrostatics there are logical reasons for describing charged materials as positive or negative. Indicates that static and current electricity are not separate areas of physics. Diagrams of experiments and circuits are included. (RT)

  10. Early African Hominids: Pedagogic Patterns.

    ERIC Educational Resources Information Center

    Newman, James L.

    1984-01-01

    By studying early African hominids, students can learn about the interactive testing and creative aspects of scientific thinking and sharpen their geographical skills. It is impossible to study this topic without giving prominence to space and time. (RM)

  11. The Main Shear Zone in Sør Rondane, East Antarctica: Implications for the late-Pan-African tectonic evolution of Dronning Maud Land

    NASA Astrophysics Data System (ADS)

    Ruppel, Antonia S.; Läufer, Andreas; Jacobs, Joachim; Elburg, Marlina; Krohne, Nicole; Damaske, Detlef; Lisker, Frank

    2015-06-01

    Structural investigations in western Sør Rondane, eastern Dronning Maud Land (DML), provide new insights into the tectonic evolution of East Antarctica. One of the main structural features is the approximately 120 km long and several hundred meters wide WSW-ENE trending Main Shear Zone (MSZ). It is characterized by dextral high-strain ductile deformation under peak amphibolite-facies conditions. Crosscutting relationships with dated magmatic rocks bracket the activity of the MSZ between late Ediacaran to Cambrian times (circa 560 to 530 Ma). The MSZ separates Pan-African greenschist- to granulite-facies metamorphic rocks with "East African" affinities in the north from a Rayner-age early Neoproterozoic gabbro-tonalite-trondhjemite-granodiorite complex with "Indo-Antarctic" affinities in the south. It is interpreted to represent an important lithotectonic strike-slip boundary at a position close to the eastern margin of the East African-Antarctic Orogen (EAAO), which is assumed to be located farther south in the ice-covered region. Together with the possibly coeval left-lateral South Orvin Shear Zone in central DML, the MSZ may be related to NE directed lateral escape of the EAAO, whereas the Heimefront Shear Zone and South Kirwanveggen Shear Zone of western DML are part of the south directed branch of this bilateral system.

  12. Linking Changes in Parenting to Parentchild Relationship Quality and Youth Self-Control: The Strong African American Families Program

    ERIC Educational Resources Information Center

    Brody, Gene H.; McBride Murry, Velma; McNair, Lily; Chen, Yi-Fu; Gibbons, Frederick X.; Gerrard, Meg; Ashby Wills, Thomas

    2005-01-01

    A randomized prevention trial was conducted contrasting families who took part in the Strong African American Families Program (SAAF), a preventive intervention for rural African American mothers and their 11-year-olds, with control families. SAAF is based on a conceptual model positing that changes in intervention-targeted parenting behaviors…

  13. Body Size and Social Self-Image among Adolescent African American Girls: The Moderating Influence of Family Racial Socialization

    ERIC Educational Resources Information Center

    Granberg, Ellen M.; Simons, Leslie Gordon; Simons, Ronald L.

    2009-01-01

    Social psychologists have amassed a large body of work demonstrating that overweight African American adolescent girls have generally positive self-images, particularly when compared with overweight females from other racial and ethnic groups. Some scholars have proposed that elements of African American social experience may contribute to the…

  14. Ebony and Ivory: Relationship between African American Young Women's Skin Color and Ratings of Self and Peers

    ERIC Educational Resources Information Center

    Nassar-McMillan, Sylvia; McFall-Roberts, Ebuni; Flowers, Claudia; Garrett, Michael T.

    2006-01-01

    Many individuals face discrimination because of their skin color; however, skin color of African American young adults has not been studied in detail. This study examines relationships between skin color and perceptions among African American college women. The study yielded a positive correlation between personal values and self-rated skin color …

  15. The Relationship among Alexithymia, Attachment Styles, and Racial Identity of African American Women in a Residential Substance Abuse Treatment Facility

    ERIC Educational Resources Information Center

    Sutherland, Vickie Mecshell

    2011-01-01

    Epidemiological studies have shown that substance abuse among African American women is occurring at an alarming rate that exceeds rates for White women. The heightened use of alcohol and drugs among African American women is a problem that resulted from their racial, historical, and structural position in American society. The literature reveals…

  16. Grass Roots and Glass Ceilings: African American Administrators in Predominantly White Colleges and Universities. SUNY Series, Frontiers in Education.

    ERIC Educational Resources Information Center

    Harvey, William B., Ed.

    This book addresses difficulties faced by African Americans in reaching the highest levels of administration in white colleges and universities. The nine chapters were written by African Americans who currently hold or have held senior-level administrative positions (deans, vice-presidents, and presidents) in predominantly white colleges and…

  17. Incorporating an African American Multicultural Self-Concept Building and Creative Arts Program into Your Class Curriculum.

    ERIC Educational Resources Information Center

    Kirkland-Holmes, Gloria; Federlein, Anne Cairns

    The incorporation of an African-American, multicultural, self-concept-building, and creative arts program into the elementary school curriculum is discussed in this conference paper. Recommendations concern the relevance to African-American children of language and communication skills, mathematics, social studies, science, positive self-concept,…

  18. Community Violence, Interpartner Conflict, Parenting, and Social Support as Predictors of the Social Competence of African American Preschool Children

    ERIC Educational Resources Information Center

    Oravecz, Linda M.; Koblinsky, Sally A.; Randolph, Suzanne M.

    2008-01-01

    Adopting an ecological framework, this study examines the role of community violence exposure, interpartner conflict, positive parenting, and informal social support in predicting the social skills and behavior problems of low-income African American preschoolers. Participants were 184 African American mothers and female caregivers of Head Start…

  19. The "Colored Schools" of Cincinnati and African American Community in Nineteenth-Century Cincinnati, 1849-1890

    ERIC Educational Resources Information Center

    Bertaux, Nancy; Washington, Michael

    2005-01-01

    The relationship between the nineteenth century Colored Public Schools of Cincinnati and the overall African American community in the nineteenth-century "borderland" city of Cincinnati is examined. It is concluded that the employment of African American teachers, while a positive development in itself, apparently failed to lead to significant…

  20. Configuring Airspace Sectors with Approximate Dynamic Programming

    NASA Technical Reports Server (NTRS)

    Bloem, Michael; Gupta, Pramod

    2010-01-01

    In response to changing traffic and staffing conditions, supervisors dynamically configure airspace sectors by assigning them to control positions. A finite horizon airspace sector configuration problem models this supervisor decision. The problem is to select an airspace configuration at each time step while considering a workload cost, a reconfiguration cost, and a constraint on the number of control positions at each time step. Three algorithms for this problem are proposed and evaluated: a myopic heuristic, an exact dynamic programming algorithm, and a rollouts approximate dynamic programming algorithm. On problem instances from current operations with only dozens of possible configurations, an exact dynamic programming solution gives the optimal cost value. The rollouts algorithm achieves costs within 2% of optimal for these instances, on average. For larger problem instances that are representative of future operations and have thousands of possible configurations, excessive computation time prohibits the use of exact dynamic programming. On such problem instances, the rollouts algorithm reduces the cost achieved by the heuristic by more than 15% on average with an acceptable computation time.

  1. Evaluation of universal newborn hearing screening in South African primary care

    PubMed Central

    Harbinson, Shannon

    2015-01-01

    Background: Universal Newborn Hearing Screening (UNHC) is the gold standard toward early hearing detection and intervention, hence the importance of its deliberation within the South African context. Aim: To determine the feasibility of screening in low-risk neonates, using Otoacoustic Emissions (OAEs), within the Midwife Obstetric Unit (MOU) three-day assessment clinic at a Community Health Centre (CHC), at various test times following birth. Method: Within a quantitative, prospective design, 272 neonates were included. Case history interviews, otoscopic examinations and Distortion Product OAEs (DPOAEs) screening were conducted at two sessions (within six hours and approximately three days after birth). Data were analysed via descriptive statistics. Results: Based on current staffing profile and practice, efficient and comprehensive screening is not successful within hours of birth, but is more so at the MOU three-day assessment clinic. Significantly higher numbers of infants were screened at session 2, with significantly less false-positive results. At session 1, only 38.1% of the neonates were screened, as opposed to more than 100% at session 2. Session 1 yielded an 82.1% rate of false positive findings, a rate that not only has important implications for the emotional well-being of the parents; but also for resource-stricken environments where expenditure has to be accounted for carefully. Conclusion: Current findings highlight the importance of studying methodologies to ensure effective reach for hearing screening within the South African context. These findings argue for UNHS initiatives to include the MOU three-day assessment to ensure that a higher number of neonates are reached and confounding variables such as vernix have been eliminated. PMID:26245605

  2. A fibrous membrane suspends the multifocal lens in the eyes of lampreys and African lungfishes.

    PubMed

    Gustafsson, Ola S E; Ekström, Peter; Kröger, Ronald H H

    2010-08-01

    The sharpness and thus information content of the retinal image in the eye depends on the optical quality of the lens and its accurate positioning in the eye. Multifocal lenses create well-focused color images and are present in the eyes of all vertebrate groups studied to date (mammals, reptiles including birds, amphibians, and ray-finned fishes) and occur even in lampreys, i.e., the most basal vertebrates with well-developed eyes. Results from photoretinoscopy obtained in this study indicate that the Dipnoi (lungfishes), i.e., the closest piscine relatives to tetrapods, also possess multifocal lenses. Suspension of the lens is complex and sophisticated in teleosts (bony fishes) and tetrapods. We studied lens suspension using light and electron microscopy in one species of lamprey (Lampetra fluviatilis) and two species of African lungfish (Protopterus aethiopicus aethiopicus and Protopterus annectens annectens). A fibrous and highly transparent membrane suspends the lens in both of these phylogenetically widely separated vertebrate groups. The membrane attaches to the lens approximately along the lens equator, from where it extends to the ora retinalis. The material forming the membrane is similar in ultrastructure to microfibrils in the zonule fibers of tetrapods. The membrane, possibly in conjunction with the cornea, iris, and vitreous body, seems suitable for keeping the lens in the correct position for well-focused imaging. Suspension of the lens by a multitude of zonule fibers in tetrapods may have evolved from a suspensory membrane similar to that in extant African lungfishes, a structure that seems to have appeared first in the lamprey-like ancestors of allextant vertebrates. PMID:20623650

  3. Doctoral training of African scientists.

    PubMed

    Doumbo, O K; Krogstad, D J

    1998-02-01

    There are two principal rationales for doctoral training of African scientists in health: 1) these scientists are essential for the nations of sub-Saharan Africa to define and implement their own health priorities, and 2) the research they perform is essential for development. However, this training is difficult because of its expense (> $20,000 per year), because many developed country mentors are unaware of the realities of research in sub-Saharan Africa, and because major differences in salary provide a financial disincentive to return. We describe a training strategy that reduces attrition because it is linked to the investigators' responsibilities before and after training, and to home country priorities. This strategy requires a close relationship between the developing country (on-site) and developed country (off-site) mentors, with joint participation in the selection and funding process, followed by course work and short-term, independent projects off-site that lead to a thesis project in the developing country, and subsequently to a defined professional position in the developing country after completion of the doctoral degree. For this strategy to succeed, the developed country mentor must have both field experience and investigative expertise; the developing country mentor must have an understanding of modern biology, as well as clinical and epidemiologic experience. In addition, we would like to emphasize that the long-term retention of these talented, highly-trained individuals requires a similar long-term commitment by their developed country mentors, well beyond the short term of most research funding. PMID:9502592

  4. Position indicator

    DOEpatents

    Tanner, David E.

    1981-01-01

    A nuclear reactor system is described in which a position indicator is provided for detecting and indicating the position of a movable element inside a pressure vessel. The movable element may be a valve element or similar device which moves about an axis. Light from a light source is transmitted from a source outside the pressure vessel to a first region inside the pressure vessel in alignment with the axis of the movable element. The light is redirected by a reflector prism to a second region displaced radially from the first region. The reflector prism moves in response to movement of the movable element about its axis such that the second region moves arcuately with respect to the first region. Sensors are arrayed in an arc corresponding to the arc of movement of the second region and signals are transmitted from the sensors to the exterior of the reactor vessel to provide indication of the position of the movable element.

  5. [Positive psychiatry].

    PubMed

    Timmerby, Nina; Austin, Stephen; Bech, Per

    2016-02-01

    Positive psychiatry (PP) is a field within psychiatry with a particular focus on promoting well-being in people who already have or are at high risk of developing mental or physical illness. PP should be considered a supplement to trad-tional psychiatry and a call for therapists in psychiatry to focus on the person as a whole rather than just as a patient. PP is in line with current national and international health policy focus on promoting positive mental health. PMID:26857411

  6. Evaluating the Effects of Vocational Training in Africa (based on the "African Economic Outlook 2008"), OECD Development Centre Policy Insights, No. 61

    ERIC Educational Resources Information Center

    Kingombe, Christian

    2008-01-01

    The impact of vocational training on economic growth and poverty reduction in African countries is unknown. Without such knowledge, however, countries and donors cannot formulate appropriate policies. Even the 35 countries surveyed in the 2008 "African Economic Outlook" can only supply approximate data. More and better data are needed to monitor…

  7. What Works? A Qualitative Examination of the Factors Related to the Academic Success of African American Males at a Predominantly White College in the South

    ERIC Educational Resources Information Center

    Robertson, Ray V.; Mason, Danielle

    2008-01-01

    Our study examined the factors related to the retention/academic success of African American males at a mid-sized, regional, predominantly white university in the south. The selected university has an African American male graduation rate, of approximately twenty three percent, which is thirteen percentage points below the national Black male…

  8. Brief Report: Under-Representation of African Americans in Autism Genetic Research--A Rationale for Inclusion of Subjects Representing Diverse Family Structures

    ERIC Educational Resources Information Center

    Hilton, Claudia L.; Fitzgerald, Robert T.; Jackson, Kelley M.; Maxim, Rolanda A.; Bosworth, Christopher C.; Shattuck, Paul T.; Geschwind, Daniel H.; Constantino, John N.

    2010-01-01

    African American children with autism are seriously under-represented in existing genetic registries and biomedical research studies of autism. We estimated the number of African American children with autism in the St. Louis region using CDC surveillance data and present the outcomes of a concerted effort to enroll approximately one-third of that…

  9. The Appointment and Conditions of Employment for African-American Law Faculty: Perspectives from inside America's Legal Academy

    ERIC Educational Resources Information Center

    Carson, Loftus C., II.

    2012-01-01

    African-Americans are underrepresented on the faculties of American law schools. Currently, it is estimated that while they make up 12.6% of the U.S. population, only approximately 4% of the tenured faculty members at historically white law schools are African American. Moreover, there is evidence that once appointed to a tenure-track law faculty…

  10. Associations of cigarette smoking with rheumatoid arthritis in African Americans

    PubMed Central

    Mikuls, Ted R.; Sayles, Harlan; Yu, Fang; LeVan, Tricia; Gould, Karen A.; Thiele, Geoffrey M.; Conn, Doyt; Jonas, Beth L.; Callahan, Leigh F.; Smith, Edwin; Brasington, Richard; Moreland, Larry W.; Reynolds, Richard; Bridges, S. Louis

    2010-01-01

    Objective To examine the associations of cigarette smoking with rheumatoid arthritis (RA) in African Americans and to determine to whether this association is impacted by HLA-DRB1 shared epitope (SE). Methods Smoking status, cumulative smoking exposure, and SE status were measured in African American patients with RA and in healthy controls. Associations of smoking with RA were examined using age- and gender-adjusted logistic regression. Additive and multiplicative SE-smoking interactions were examined. Results After adjusting for age and gender, ever (OR = 1.45; 95% CI 1.07 to 1.97) and current smoking (OR = 1.56; 95% CI 1.07 to 2.26) were more common in African American RA cases (n = 605) than in controls (n = 255). The association of smoking with RA was limited to those with a cumulative exposure exceeding 10 pack-years, associations that were evident in both autoantibody positive and negative disease. There was evidence of a significant additive interaction between SE status and heavy smoking (≥ 10 pack-years) in RA risk (attributable proportion due to interaction [AP] of 0.58, p = 0.007) with an AP of 0.47 (p = 0.006) between SE status and ever smoking. There was no evidence of multiplicative interactions. Conclusion Among African Americans, cigarette smoking is associated not only with the risk of autoantibody positive RA but also with the risk of autoantibody negative disease. RA risk attributable to smoking is limited to African Americans with more than 10 pack-years of exposure and is more pronounced among individuals positive for HLA-DRB1 SE. PMID:20722010

  11. African fossil tali: further multivariate morphometric studies.

    PubMed

    Lisowski, F P; Albrecht, G H

    1976-07-01

    Analysis of measurements from the tali of 21 individual fossil primates from Africa shows that the specimens fall into five clearly defined groups. Accordingly, these specimens have been included as groups along with extant species in a subsequent canonical analysis thus allowing the fossils to play their part in the determination of the canonical separations. The results of this procedure show that the five fossil groups lie in a part of the canonical space not occupied by any extant African primate. Their positions are between the envelope of Asiatic apes (Hylobates and Pongo) and the envelope of African forms near the edge which contains Pan and Papio. One fossil group is so similar to Hylobates that its talus may have functioned in locomotion in a parallel manner. Others lie near to Pongo in directions proceeding towards Pan and Papio and it is possible that this similarity may indicate remnants of morphological adaptation for climbing in these fossils. At the same time, however, individual specimens are closer to one or another of the extant groups and this considerable spread suggests that the locomotor adaptations as evidenced by talar morphology, of the primate fauna in Africa, may have been very different from those of the present day. This would not the inconsistent with the different habitats, floras and non-primate faunas that may have characterized the East African scene at these earlier times. Particular fossils from Olduvai and Kromdraai that are supposed to be australopithecine and therefore bipeds, are confirmed (Oxnard, '72; Lisowski et al., '74) as being totally different from man in their talar morphology and essentially rather similar to the majority of the other fossil tali examined. PMID:961834

  12. Approximate Calculation of the Static Longitudinal Stability of Airplanes

    NASA Technical Reports Server (NTRS)

    Bienen, Theodor

    1926-01-01

    It seems desirable to have some simple method for calculating quickly and with sufficient accuracy: 1) the correct position of the center of gravity; 2) the requisite tail-group dimensions; 3) and the course of the wing and tail-group moments. In out deductions, we will first replace the biplane (disregarding the effect of stagger, decalage and induced drag) by an equivalent monoplane, whose dimensions and position in space can be approximately determined in a simple manner.

  13. East African Rift

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Places where the earth's crust has formed deep fissures and the plates have begun to move apart develop rift structures in which elongate blocks have subsided relative to the blocks on either side. The East African Rift is a world-famous example of such rifting. It is characterized by 1) topographic deep valleys in the rift zone, 2) sheer escarpments along the faulted walls of the rift zone, 3) a chain of lakes within the rift, most of the lakes highly saline due to evaporation in the hot temperatures characteristic of climates near the equator, 4) voluminous amounts of volcanic rocks that have flowed from faults along the sides of the rift, and 5) volcanic cones where magma flow was most intense. This example in Kenya displays most of these features near Lake Begoria.

    The image was acquired December 18, 2002, covers an area of 40.5 x 32 km, and is located at 0.1 degrees north latitude, 36.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  14. Positive psychotherapy.

    PubMed

    Seligman, Martin E P; Rashid, Tayyab; Parks, Acacia C

    2006-11-01

    Positive psychotherapy (PPT) contrasts with standard interventions for depression by increasing positive emotion, engagement, and meaning rather than directly targeting depressive symptoms. The authors have tested the effects of these interventions in a variety of settings. In informal student and clinical settings, people not uncommonly reported them to be "life-changing." Delivered on the Web, positive psychology exercises relieved depressive symptoms for at least 6 months compared with placebo interventions, the effects of which lasted less than a week. In severe depression, the effects of these Web exercises were particularly striking. This address reports two preliminary studies: In the first, PPT delivered to groups significantly decreased levels of mild-to-moderate depression through 1-year follow-up. In the second, PPT delivered to individuals produced higher remission rates than did treatment as usual and treatment as usual plus medication among outpatients with major depressive disorder. Together, these studies suggest that treatments for depression may usefully be supplemented by exercises that explicitly increase positive emotion, engagement, and meaning. ((c) 2006 APA, all rights reserved). PMID:17115810

  15. An African ethic for nursing?

    PubMed

    Haegert, S

    2000-11-01

    This article derives from a doctoral thesis in which a particular discourse was used as a 'paradigm case'. From this discourse an ethic set within a South African culture arose. Using many cultural 'voices' to aid the understanding of this narrative, the ethic shows that one can build on both a 'justice' and a 'care' ethic. With further development based on African culture one can take the ethic of care deeper and reveal 'layers of understanding'. Care, together with compassion, forms the foundation of morality. Nursing ethics has followed particular western moral philosophers. Often nursing ethics has been taught along the lines of Kohlberg's theory of morality, with its emphasis on rules, rights, duties and general obligations. These principles were universalistic, masculine and noncontextual. However, there is a new ethical movement among Thomist philosophers along the lines to be expounded in this article. Nurses such as Benner, Bevis, Dunlop, Fry and Gadow--to name but a few--have welcomed the concept of an 'ethic of care'. Gilligan's work gave a feminist view and situated ethics in the everyday aspects of responsiveness, responsibility, context and concern. Shutte's search for a 'philosophy for Africa' has resulted in finding similarities in Setiloane and in Senghor with those of Thomist philosophers. Using this African philosophy and a research participant's narrative, an African ethic evolves out of the African proverb: 'A person is a person through other persons', or its alternative rendering: 'I am because we are: we are because I am.' This hermeneutic narrative reveals 'the way affect imbues activity with ethical meaning' within the context of a black nursing sister in a rural South African hospital. It expands upon the above proverb and incorporates the South African constitutional idea of 'Ubuntu' (compassion and justice or humanness). PMID:11221391

  16. Reducing Stress and Preventing Anxiety in African American Adolescents: A Culturally- Grounded Approach

    PubMed Central

    Robinson, W. LaVome; Droege, Jocelyn R.; Case, Mary H.; Jason, Leonard A.

    2016-01-01

    Evidenced-based and culturally adapted stress-reduction interventions for urban African American adolescents who are at risk for anxiety and other problems related to stress are needed. This study presents intervention components and preliminary outcome findings of a culturally adapted stress-reduction intervention for urban African American adolescents. Preliminary findings support the efficacy of the intervention to reduce anxiety and enhance general cognitive competencies, such as coping strategies, self-efficacy, and positive thinking, among participants, in comparison to controls. Clinical implications of the stress-reduction intervention for the prevention of psychopathology, particularly among African American adolescents, are discussed. PMID:27042702

  17. Discrimination, religious coping, and tobacco use among White, African American, and Mexican American vocational school students.

    PubMed

    Horton, Karissa D; Loukas, Alexandra

    2013-03-01

    This study examined whether religious coping moderates the impact of racial/ethnic discrimination on current (past 30 day) cigarette and cigar/cigarillo use among a racially/ethnically diverse sample of 984 technical/vocational school students (47.1% women; mean age = 25 years). Results indicate that discrimination increased the likelihood of current cigarette use among African American students and current cigar/cigarillo use among white and African American students. Positive religious coping decreased the likelihood of cigarette and cigar/cigarillo smoking for white students only. Negative religious coping increased the likelihood of cigarette use for white students and cigar/cigarillo use for white and African American students. Two 2-way interactions indicate that positive and negative religious coping moderate the discrimination-cigarette smoking relationship for African American and Mexican American students, respectively. PMID:21249522

  18. Producing approximate answers to database queries

    NASA Technical Reports Server (NTRS)

    Vrbsky, Susan V.; Liu, Jane W. S.

    1993-01-01

    We have designed and implemented a query processor, called APPROXIMATE, that makes approximate answers available if part of the database is unavailable or if there is not enough time to produce an exact answer. The accuracy of the approximate answers produced improves monotonically with the amount of data retrieved to produce the result. The exact answer is produced if all of the needed data are available and query processing is allowed to continue until completion. The monotone query processing algorithm of APPROXIMATE works within the standard relational algebra framework and can be implemented on a relational database system with little change to the relational architecture. We describe here the approximation semantics of APPROXIMATE that serves as the basis for meaningful approximations of both set-valued and single-valued queries. We show how APPROXIMATE is implemented to make effective use of semantic information, provided by an object-oriented view of the database, and describe the additional overhead required by APPROXIMATE.

  19. African desert dust in the Caribbean atmosphere: Microbiology and public health

    USGS Publications Warehouse

    Griffin, Dale W.; Garrison, V.H.; Herman, J.R.; Shinn, E.A.

    2001-01-01

    Air samples collected on St. John in the U.S. Virgin Islands were screened for the presence of viable bacteria and fungi to determine if the number of cultivatable microbes in the atmosphere differed between "clear atmospheric conditions" and "African dust-events." Results indicate that during "African dust-events," the numbers of cultivatable airborne microorganisms can be 2 to 3 times that found during "clear atmospheric conditions." Direct microbial counts of air samples using an epifluorescent microscopy assay demonstrated that during an "African dust-event," bacteria-like and virus-like particle counts were approximately one log greater than during "clear atmospheric conditions." Bacteria-like particles exhibiting autofluoresence, a trait of phototrophs, were only detected during an "African dust-event.".

  20. Observed Oceanic and Terrestrial Drivers of North African Climate

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Notaro, M.; Wang, F.; Mao, J.; Shi, X.; Wei, Y.

    2015-12-01

    Hydrologic variability can pose a serious threat to the poverty-stricken regions of North Africa. Yet, the current understanding of oceanic versus terrestrial drivers of North African droughts/pluvials is largely model-based, with vast disagreement among models. In order to identify the observed drivers of North African climate and develop a benchmark for model evaluations, the multivariate Generalized Equilibrium Feedback Assessment (GEFA) is applied to observations, remotely sensed data, and reanalysis products. The identified primary oceanic drivers of North African rainfall variability are the Atlantic, tropical Indian, and tropical Pacific Oceans and Mediterranean Sea. During the summer monsoon, positive tropical eastern Atlantic sea-surface temperature (SST) anomalies are associated with a southward shift of the Inter-Tropical Convergence Zone, enhanced ocean evaporation, and greater precipitable water across coastal West Africa, leading to increased West African monsoon (WAM) rainfall and decreased Sahel rainfall. During the short rains, positive SST anomalies in the western tropical Indian Ocean and negative anomalies in the eastern tropical Indian Ocean support greater easterly oceanic flow, evaporation over the western ocean, and moisture advection to East Africa, thereby enhancing rainfall. The sign, magnitude, and timing of observed vegetation forcing on rainfall vary across North Africa. The positive feedback of leaf area index (LAI) on rainfall is greatest during DJF for the Horn of Africa, while it peaks in autumn and is weakest during the summer monsoon for the Sahel. Across the WAM region, a positive LAI anomaly supports an earlier monsoon onset, increased rainfall during the pre-monsoon, and decreased rainfall during the wet season. Through unique mechanisms, positive LAI anomalies favor enhanced transpiration, precipitable water, and rainfall across the Sahel and Horn of Africa, and increased roughness, ascent, and rainfall across the WAM region

  1. Spin-1 Heisenberg ferromagnet using pair approximation method

    NASA Astrophysics Data System (ADS)

    Mert, Murat; Kılıç, Ahmet; Mert, Gülistan

    2016-06-01

    Thermodynamic properties for Heisenberg ferromagnet with spin-1 on the simple cubic lattice have been calculated using pair approximation method. We introduce the single-ion anisotropy and the next-nearest-neighbor exchange interaction. We found that for negative single-ion anisotropy parameter, the internal energy is positive and heat capacity has two peaks.

  2. The Inertial Property of Approximately Inertial Frames of Reference

    ERIC Educational Resources Information Center

    Chubykalo, Andrew E.; Espinoza, Augusto; Kosyakov, B. P.

    2011-01-01

    Is it possible to compare approximately inertial frames in the inertial property? If this is the case, the inertial property becomes a measurable quantity. We give a positive answer to this question, and discuss the general principle of design of devices for making the required measurements. This paper is intended for advanced undergraduate and…

  3. Relative rates of evolution in the coding and control regions of African mtDNAs.

    PubMed

    Howell, Neil; Elson, Joanna L; Howell, Corinna; Turnbull, Douglass M

    2007-10-01

    Reduced median networks of African haplogroup L mitochondrial DNA (mtDNA) sequences were analyzed to determine the pattern of substitutions in both the noncoding control and coding regions. In particular, we attempted to determine the causes of the previously reported (Howell et al. 2004) violation of the molecular clock during the evolution of these sequences. In the coding region, there was a significantly higher rate of substitution at synonymous sites than at nonsynonymous sites as well as in the tRNA and rRNA genes. This is further evidence for the operation of purifying selection during human mtDNA evolution. For most sites in the control region, the relative rate of substitution was similar to the rate of neutral evolution (assumed to be most closely approximated by the substitution rate at 4-fold degenerate sites). However, there are a number of mutational hot spots in the control region, approximately 3% of the total sites, that have a rate of substitution greater than the neutral rate, at some sites by more than an order of magnitude. It is possible either that these sites are evolving under conditions of positive selection or that the substitution rate at some sites in the control region is strongly dependent upon sequence context. Finally, we obtained preliminary evidence for "nonideal" evolution in the control region, including haplogroup-specific substitution patterns and a decoupling between relative rates of substitution in the control and coding regions. PMID:17642471

  4. Position sensor

    NASA Technical Reports Server (NTRS)

    Auer, Siegfried (Inventor)

    1988-01-01

    A radiant energy angle sensor is provided wherein the sensitive portion thereof comprises a pair of linear array detectors with each detector mounted normal to the other to provide X and Y channels and a pair of slits spaced from the pair of linear arrays with each of the slits positioned normal to its associated linear array. There is also provided electrical circuit means connected to the pair of linear array detectors and to separate X and Y axes outputs.

  5. Correlates of African American Men's Sexual Schemas

    PubMed Central

    Morales, Dawn A.; Coyne-Beasley, Tamera; St. Lawrence, Janet

    2013-01-01

    Sexual schemas are cognitive representations of oneself as a sexual being and aid in the processing of sexually relevant information. We examined the relationship between sociosexuality (attitudes about casual sex), masculine ideology (attitudes toward traditional men and male roles), and cultural centrality (strength of identity with racial group) as significant psychosocial and sociocultural predictors in shaping young, heterosexual African American men's sexual schemas. A community sample (n=133) of men in a southeastern city of the United States completed quantitative self-report measures examining their attitudes and behavior related to casual sex, beliefs about masculinity, racial and cultural identity, and self-views of various sexual aspects of themselves. Results indicated that masculine ideology and cultural centrality were both positively related to men's sexual schemas. Cultural centrality explained 12 % of the variance in level of sexual schema, and had the strongest correlation of the predictor variables with sexual schema (r=.36). The need for more attention to the bidirectional relationships between masculinity, racial/cultural identity, and sexual schemas in prevention, intervention, and public health efforts for African American men is discussed. PMID:24031118

  6. Pheochromocytoma in an African warthog (Phacochoerus aethiopicus).

    PubMed

    Cole, Gretchen; Suedmeyer, W Kirk; Johnson, Gayle

    2008-12-01

    A 14-yr-old male African warthog (Phacochoerus aethiopicus) with a chronic history of intermittent unilateral epistaxis, degenerative osteoarthritis, and intermittent weakness in the distal lumbar trunk was evaluated to determine the source of epistaxis. No obvious cause was determined, and in light of severe osteoarthritis and a holosystolic cardiac murmur, the animal was euthanized. A tumor of the right adrenal gland involving the medulla was found at gross necropsy. Immunohistochemical staining of the tumor was positive for chromogranin and negative for neurofilament protein, which was diagnostic for pheochromocytoma. No lesions were observed in either nasal cavity. Systolic, diastolic, and mean arterial pressures measured at the time of immobilization were elevated when compared with another African warthog immobilized with a similar anesthetic regimen. Additionally, the warthog had pronounced serum norepinephrine dominance with a norepinephrine:epinephrine ratio of 10.0, compared with 0.36 from clinically normal warthogs. Practitioners should consider pheochromocytoma when evaluating warthogs or swine for epistaxis. PMID:19110715

  7. African American Males. A Critical Link in the African American Family.

    ERIC Educational Resources Information Center

    Jones, Dionne J., Ed.

    African Americans are experiencing extreme stress in the United States, and African-American males appear to suffer the most. The chapters in this volume examine some of the issues confronting African-American men today. They include: (1) "Introduction" (Dionne J. Jones); (2) "Reaffirming Young African American Males: Mentoring and Community…

  8. African American Preschoolers' Language, Emergent Literacy Skills, and Use of African American English: A Complex Relation

    ERIC Educational Resources Information Center

    Connor, Carol McDonald; Craig, Holly K.

    2006-01-01

    Purpose: This study examined the relation between African American preschoolers' use of African American English (AAE) and their language and emergent literacy skills in an effort to better understand the perplexing and persistent difficulties many African American children experience learning to read proficiently. Method: African American…

  9. Positive Psychologists on Positive Constructs

    ERIC Educational Resources Information Center

    Lyubomirsky, Sonja

    2012-01-01

    Comments on the original article by McNulty and Fincham (see record 2011-15476-001). In their article, the authors offered compelling evidence that constructs such as forgiveness and optimism can have both beneficial and adverse consequences, depending on the context. Their caution about labeling particular psychological processes as "positive" is…

  10. Living positively as HIV positive.

    PubMed

    Garraty, Sarah J

    2011-01-01

    A nursing student records a brief biography of a Zambian nurse and certified midwife living with HIV/AIDS while shadowing the nurse during an undergraduate cross-cultural course in Macha, Zambia in January 2009. The nurse strives to live positively, educating, encouraging, and empowering others. PMID:21294466

  11. Mapping the state of the field of social psychology in Africa and patterns of collaboration between African and international social psychologists.

    PubMed

    Quayle, Michael; Greer, Megan

    2014-12-01

    Patterns of collaboration in social psychology from 2000 to 2010 were mapped to analyse the position of African authors in the international co-authorship network using bibliographic records from the Thomson Reuters Web of Knowledge. There are very few social psychologists working in Africa, with the majority of these located in South Africa. Indeed, some small European countries boast more social psychologists than the entire continent of Africa. African authors published less than their non-African collaborators, but had comparable status on joint publications. Co-authorship relationships between African researchers from different African countries were generally mediated by partners from other continents, and direct collaboration between non-compatriot African authors was very rare. The small size, and extremely sparse connection of the African co-authorship network, is likely to be an obstacle both in the development of social psychology as a universally relevant discipline and in the penetration of social psychological knowledge in Africa. PMID:25355672

  12. Technical Consulting: The African-American Perspective

    ERIC Educational Resources Information Center

    Whitfield, Tracy N.

    2010-01-01

    The qualitative research study explored the organizational characteristics necessary in addressing the low concentration of African American technical consultants employed in the information technology industry. Using research participants' professional experience, participants responded to a developed questionnaire. African American technical…

  13. Towards an African Philosophy of Education.

    ERIC Educational Resources Information Center

    Ocaya-Lakidi, Dent

    1980-01-01

    Compares and contrasts contemporary philosophies of education in Africa with two philosophical doctrines (naturalism and idealism). Topics discussed include value selectors, westernization, the role of missionaries in African education, critical consciousness, relevance, and African education today. (DB)

  14. African N Assessment

    NASA Astrophysics Data System (ADS)

    Bekunda, M.; Galford, G. L.; Hickman, J. E.; Palm, C.

    2011-12-01

    Africa's smallholder agricultural systems face unique challenges in planning for reducing poverty, concurrent with adaptation and mitigation to climate change. At continental level, policy seeks to promote a uniquely African Green Revolution to increase crop yields and food production, and improve local livelihoods. However, the consequences on the environment and climate are not clear; these pro-economic development measures should be linked to climate change adaptation and mitigation measures, and research is required to help achieve these policy proposals by identifying options, and testing impacts. In particular, increased nitrogen (N) inputs are essential for increasing food production in Africa, but are accompanied by inevitable increases in losses to the environment. These losses appear to be low at input levels promoted in agricultural development programs, while the increased N inputs both increase current food production and appear to reduce the vulnerability of food production to changes in climate. We present field and remote sensing evidence from Malawi that subsidizing improved seed and fertilizers increases resilience to drought without adding excess N to the environment. In Kenya, field research identified thresholds in N2O losses, where emissions are very low at fertilization rates of less than 200 kg ha-1. Village-scale models have identified potential inefficiencies in the food production process where the largest losses of reactive N occur, and which could be targeted to reduce the amount of N released to the environment. We further review some on-going research activities and progress in Africa that compare different methods of managing resources that target resilience in food production and adaptation to climate change, using nutrient N as an indicator, while evaluating the effects of these resource management practices on ecosystems and the environment.

  15. Preliminary performance assessment of computer automated facial approximations using computed tomography scans of living individuals.

    PubMed

    Parks, Connie L; Richard, Adam H; Monson, Keith L

    2013-12-10

    ReFace (Reality Enhancement Facial Approximation by Computational Estimation) is a computer-automated facial approximation application jointly developed by the Federal Bureau of Investigation and GE Global Research. The application derives a statistically based approximation of a face from a unidentified skull using a dataset of ~400 human head computer tomography (CT) scans of living adult American individuals from four ancestry groups: African, Asian, European and Hispanic (self-identified). To date only one unpublished subjective recognition study has been conducted using ReFace approximations. It indicated that approximations produced by ReFace were recognized above chance rates (10%). This preliminary study assesses: (i) the recognizability of five ReFace approximations; (ii) the recognizability of CT-derived skin surface replicas of the same individuals whose skulls were used to create the ReFace approximations; and (iii) the relationship between recognition performance and resemblance ratings of target individuals. All five skin surface replicas were recognized at rates statistically significant above chance (22-50%). Four of five ReFace approximations were recognized above chance (5-18%), although with statistical significance only at the higher rate. Such results suggest reconsideration of the usefulness of the type of output format utilized in this study, particularly in regard to facial approximations employed as a means of identifying unknown individuals. PMID:24314512

  16. Characteristics of At-Risk Youth Served by the Positive Impact Program (PIP).

    ERIC Educational Resources Information Center

    Cobbs, Charles R.; And Others

    Because of the threat of gangs, drugs and violence in their community, in the fall of 1990 16 African-American men started the Positive Impact Program (PIP) in Wynne, Arkansas for at-risk African-American boys. The program was originally developed to serve boys in kindergarten through eighth grade, but it has recently been made available to all…

  17. Role Model Behavior and Youth Violence: A Study of Positive and Negative Effects

    ERIC Educational Resources Information Center

    Hurd, Noelle M.; Zimmerman, Marc A.; Reischl, Thomas M.

    2011-01-01

    The study investigated how role models' behavior may positively or negatively influence African American early adolescents' attitudes toward violence and violent behavior. Participants in this study included 331 African American seventh and eighth graders from low-income neighborhoods in an urban, Midwestern city. The study used a model developed…

  18. The African Cultural Astronomy Project

    NASA Astrophysics Data System (ADS)

    Urama, Johnson O.; Holbrook, Jarita C.

    2011-06-01

    Indigenous, endogenous, traditional, or cultural astronomy focuses on the many ways that people and cultures interact with celestial bodies. In most parts of Africa, there is very little or no awareness about modern astronomy. However, like ancient people everywhere, Africans wondered at the sky and struggled to make sense of it. The African Cultural Astronomy Project aims to unearth the body of traditional knowledge of astronomy possessed by peoples of the different ethnic groups in Africa and to consider scientific interpretations when appropriate for cosmogonies and ancient astronomical practices. Regardless of scientific validity, every scientist can relate to the process of making observations and creating theoretical mechanisms for explaining what is observed. Through linking the traditional and the scientific, it is believed that this would be used to create awareness and interest in astronomy in most parts of Africa. This paper discusses the vision, challenges and prospects of the African Cultural Astronomy Project in her quest to popularize astronomy in Africa.

  19. West African crude production diversifies

    SciTech Connect

    Aalund, L.

    1983-06-01

    Nigeria, with its seven crude-oil export streams, dominated West African production and accounted for over 70% of the depressed 1.8 million b/d output from the region last year. However, during the 1970s a flurry of new producing fields, primarily off the African coast, diversified production among a number of countries and touched off a wave of oil activity. The Journal takes a close look at the quality of West African oil in this installment of assays on world export crudes. This issue covers, in alphabetical order, Bonny Light (Nigeria) to Espoir (Ivory Coast). A following issue will wrap up West Africa by presenting assays on crudes from Forcados Blend (Nigeria) to Zaire Crude (Zaire).

  20. Plio-pleistocene African climate

    SciTech Connect

    deMenocal, P.B.

    1995-10-06

    Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated. 65 refs., 6 figs.

  1. Plio-Pleistocene African Climate

    NASA Astrophysics Data System (ADS)

    Demenocal, Peter B.

    1995-10-01

    Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated.

  2. An approximation technique for jet impingement flow

    SciTech Connect

    Najafi, Mahmoud; Fincher, Donald; Rahni, Taeibi; Javadi, KH.; Massah, H.

    2015-03-10

    The analytical approximate solution of a non-linear jet impingement flow model will be demonstrated. We will show that this is an improvement over the series approximation obtained via the Adomian decomposition method, which is itself, a powerful method for analysing non-linear differential equations. The results of these approximations will be compared to the Runge-Kutta approximation in order to demonstrate their validity.

  3. Comparison of two Pareto frontier approximations

    NASA Astrophysics Data System (ADS)

    Berezkin, V. E.; Lotov, A. V.

    2014-09-01

    A method for comparing two approximations to the multidimensional Pareto frontier in nonconvex nonlinear multicriteria optimization problems, namely, the inclusion functions method is described. A feature of the method is that Pareto frontier approximations are compared by computing and comparing inclusion functions that show which fraction of points of one Pareto frontier approximation is contained in the neighborhood of the Edgeworth-Pareto hull approximation for the other Pareto frontier.

  4. Positioning apparatus

    DOEpatents

    Vogel, Max A.; Alter, Paul

    1986-05-06

    An apparatus for precisely positioning materials test specimens within the optimum neutron flux path emerging from a neutron source located in a housing. The test specimens are retained in a holder mounted on the free end of a support pivotably mounted and suspended from a movable base plate. The support is gravity biased to urge the holder in a direction longitudinally of the flux path against the housing. Means are provided for moving the base plate in two directions to effect movement of the holder in two mutually perpendicular directions normal to the axis of the flux path.

  5. Positioning apparatus

    DOEpatents

    Vogel, Max A.; Alter, Paul

    1986-01-01

    An apparatus for precisely positioning materials test specimens within the optimum neutron flux path emerging from a neutron source located in a housing. The test specimens are retained in a holder mounted on the free end of a support pivotably mounted and suspended from a movable base plate. The support is gravity biased to urge the holder in a direction longitudinally of the flux path against the housing. Means are provided for moving the base plate in two directions to effect movement of the holder in two mutually perpendicular directions normal to the axis of the flux path.

  6. POSITIONING DEVICE

    DOEpatents

    Wall, R.R.; Peterson, D.L.

    1959-09-15

    A positioner is described for a vertical reactor-control rod. The positioner comprises four grooved friction rotatable members that engage the control rod on all sides and shift it longitudinally. The four friction members are drivingly interconnected for conjoint rotation and comprise two pairs of coaxial members. The members of each pair are urged toward one another by hydraulic or pneumatic pressure and thus grip the control rod so as to hold it in any position or adjust it. Release of the by-draulic or pneumatic pressure permits springs between the friction members of each pair to force them apart, whereby the control rod moves quickly by gravity into the reactor.

  7. Positioning apparatus

    DOEpatents

    Vogel, M.A.; Alter, P.

    1983-07-07

    An apparatus is provided for precisely adjusting the position of an article relative to a beam emerging from a neutron source disposed in a housing. The apparatus includes a support pivotably mounted on a movable base plate and freely suspended therefrom. The support is gravity biased toward the housing and carries an article holder movable in a first direction longitudinally of the axis of said beam and normally urged into engagement against said housing. Means are provided for moving the base plate in two directions to effect movement of the suspended holder in two mutually perpendicular directions, respectively, normal to the axis of the beam.

  8. The Education of African-Americans.

    ERIC Educational Resources Information Center

    Willie, Charles V., Ed.; And Others

    The 17 papers in this volume are products of a study group on the education of African Americans that was part of a national project, "The Assessment of the Status of African-Americans." The volume takes a comprehensive look at the education of African Americans, specifically early childhood through postsecondary education, and relevant public…

  9. An Introduction to West African Literature.

    ERIC Educational Resources Information Center

    Taiwo, Oladele

    Intended to provide help for those interested in studying West African literature, this book is divided into three parts. Part One provides background information: the various African oral traditions are discussed, related to the way of life of the people, and examined for the extent to which they form the basis of present West African literary…

  10. Engaging African Americans in Smoking Cessation Programs

    ERIC Educational Resources Information Center

    Wallen, Jacqueline; Randolph, Suzanne; Carter-Pokras, Olivia; Feldman, Robert; Kanamori-Nishimura, Mariano

    2014-01-01

    Background: African Americans are disproportionately exposed to and targeted by prosmoking advertisements, particularly menthol cigarette ads. Though African Americans begin smoking later than whites, they are less likely to quit smoking than whites. Purpose: This study was designed to explore African American smoking cessation attitudes,…

  11. Freedom Road: Adult Education of African Americans.

    ERIC Educational Resources Information Center

    Peterson, Elizabeth A., Ed.

    This book contains six chapters by various authors about the history of African Americans' contributions and participation in adult education. The book reports on how some African American leaders saw the connection between education and the eventual freedom or uplift of the African American people. Following a foreword (Phyllis M. Cunningham) and…

  12. A Scale To Assess African American Acculturation.

    ERIC Educational Resources Information Center

    Snowden, Lonnie R.; Hines, Alice M.

    1999-01-01

    Investigated an acculturation scale designed for use in the African-American population. Responses from more than 900 African Americans generally indicate an African-American orientation within the sample, although there are notable variations on all 10 scale items. Discusses evidence for scale reliability and validity. (SLD)

  13. Towards a Norm in South African Englishes.

    ERIC Educational Resources Information Center

    van der Walt, Johann L.; van Rooy, Bertus

    2002-01-01

    Investigates the perception and application of the norm in South African English with specific reference to Black South African English. Hypothesizes that South African English is in the hibernation and expansion phase. Three sets of data are presented and analyzed. (Author/VWL)

  14. African Heritage Curriculum Materials. Teacher's Manual.

    ERIC Educational Resources Information Center

    Museum of African Art, Washington, DC.

    This guide for secondary teachers focuses on sub-Saharan (Black) African history and culture. Although the guide is intended to be used in conjunction with the audiovisual materials on African heritage produced by the Museum of African Art, it can also be used as a source of background reading for teachers and as a guide to additional…

  15. Fractal Trigonometric Polynomials for Restricted Range Approximation

    NASA Astrophysics Data System (ADS)

    Chand, A. K. B.; Navascués, M. A.; Viswanathan, P.; Katiyar, S. K.

    2016-05-01

    One-sided approximation tackles the problem of approximation of a prescribed function by simple traditional functions such as polynomials or trigonometric functions that lie completely above or below it. In this paper, we use the concept of fractal interpolation function (FIF), precisely of fractal trigonometric polynomials, to construct one-sided uniform approximants for some classes of continuous functions.

  16. Rainbows: Mie computations and the Airy approximation.

    PubMed

    Wang, R T; van de Hulst, H C

    1991-01-01

    Efficient and accurate computation of the scattered intensity pattern by the Mie formulas is now feasible for size parameters up to x = 50,000 at least, which in visual light means spherical drops with diameters up to 6 mm. We present a method for evaluating the Mie coefficients from the ratios between Riccati-Bessel and Neumann functions of successive order. We probe the applicability of the Airy approximation, which we generalize to rainbows of arbitrary p (number of internal reflections = p - 1), by comparing the Mie and Airy intensity patterns. Millimeter size water drops show a match in all details, including the position and intensity of the supernumerary maxima and the polarization. A fairly good match is still seen for drops of 0.1 mm. A small spread in sizes helps to smooth out irrelevant detail. The dark band between the rainbows is used to test more subtle features. We conclude that this band contains not only externally reflected light (p = 0) but also a sizable contribution f rom the p = 6 and p = 7 rainbows, which shift rapidly with wavelength. The higher the refractive index, the closer both theories agree on the first primary rainbow (p = 2) peak for drop diameters as small as 0.02 mm. This may be useful in supporting experimental work. PMID:20581954

  17. Mental health promotion for vulnerable African American youth.

    PubMed

    Shelton, Deborah; Lyon-Jenkins, Nina

    2006-01-01

    Fifty-six African American youth between 10-14 years of age participated in a community-based 14-week expressive arts program designed for youth at risk of involvement with the juvenile justice system. Positive and statistically significant findings for pre-post changes in self-control, protective factors, and resilience were found. Difficulty in engaging parents and the strong racial biases of the community appear to have influenced the lack of improvement in self-esteem scores. PMID:17073393

  18. “I Do But I Don't”: The Search for Identity in Urban African American Adolescents

    PubMed Central

    Gullan, Rebecca Lakin; Hoffman, Beth Necowitz; Leff, Stephen S.

    2014-01-01

    Achievement of a coherent and strong sense of self is critical to positive academic outcomes for urban minority youth. The present study utilized a mixed-methods approach to explore key aspects of identity development for African American adolescents living in a high-poverty, urban neighborhood. Results suggest that efforts to develop a sense of oneself as an individual and in relation to the world are impeded by mixed messages on African American culture and achievement. Findings are discussed in the context of teaching and working with urban African American adolescents in a way that promotes positive identity development. PMID:25485041

  19. PUBLISHING SOUTH AFRICAN SCHOLARSHIP IN THE GLOBAL ACADEMIC COMMUNITY.

    PubMed

    Le Roux, Elizabeth

    2015-09-20

    South Africa's academic publishing history has been profoundly influenced by its colonial heritage. This is reflected in the publication of Transactions of the South African Philosophical Society (later, the Royal Society of South Africa) from 1878. Although the Society and journal sought to promote original research about South Africa, it was modelled after the Royal Society in London and formed part of an imperial scientific community. As the local higher education institutions grew more independent and research-focused, local scholarly publishing developed as well, with university presses playing an increasingly important role. The University of South Africa (Unisa) Press started publishing departmental journals in the 1950s, with a focus on journals that 'speak to the student', and it is today the only South African university press with an active journals publishing programme. As external funding declined and the country became intellectually isolated in the high apartheid period, the Press managed to attract journals that could no longer be subsidized by learned societies and other universities. More recently, new co-publishing arrangements have brought South African journals back into an international intellectual community. Although some argue that this constitutes a re-colonization of South African knowledge production, it is also an innovative strategy for positioning local research in a global context. PMID:26495579

  20. Aerosol interactions with African/Atlantic climate dynamics

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.

    2014-07-01

    Mechanistic relationships exist between variability of dust in the oceanic Saharan air layer (OSAL) and transient changes in the dynamics of Western Africa and the tropical Atlantic Ocean. This study provides evidence of possible interactions between dust in the OSAL region and African easterly jet-African easterly wave (AEJ-AEW) system in the climatology of boreal summer, when easterly wave activity peaks. Synoptic-scale changes in instability and precipitation in the African/Atlantic intertropical convergence zone are correlated with enhanced aerosol optical depth (AOD) in the OSAL region in response to anomalous 3D overturning circulations and upstream/downstream thermal anomalies at above and below the mean-AEJ level. Upstream and downstream anomalies are referred to the daily thermal/dynamical changes over the West African monsoon region and the Eastern Atlantic Ocean, respectively. Our hypothesis is that AOD in the OSAL is positively correlated with the downstream AEWs and negatively correlated with the upstream waves from climatological perspective. The similarity between the 3D pattern of thermal/dynamical anomalies correlated with dust outbreaks and those of AEWs provides a mechanism for dust radiative heating in the atmosphere to reinforce AEW activity. We proposed that the interactions of OSAL dust with regional climate mainly occur through coupling of dust with the AEWs.

  1. Examining Contextual Factors in the Career Decision Status of African American Adolescents

    ERIC Educational Resources Information Center

    Constantine, Madonna G.; Wallace, Barbara C.; Kindaichi, Mai M.

    2005-01-01

    This study examined the extent to which perceived occupational barriers and perceived parental support predicted career certainty and career indecision in a sample of African American adolescents. Perceived occupational barriers were positively predictive of career indecision, and perceived parental support was positively associated with career…

  2. Racial Pride and Religiosity among African American Boys: Implications for Academic Motivation and Achievement

    ERIC Educational Resources Information Center

    Butler-Barnes, Sheretta T.; Williams, Terrinieka T.; Chavous, Tabbye M.

    2012-01-01

    The persistent underachievement among African American boys has led to increased empirical inquiry, yet little research considers within-group variation in achievement nor positive youth characteristics that help explain positive achievement outcomes. This study conceptualized culturally-based factors (racial pride and religiosity) as adolescent…

  3. A unified approach to the Darwin approximation

    SciTech Connect

    Krause, Todd B.; Apte, A.; Morrison, P. J.

    2007-10-15

    There are two basic approaches to the Darwin approximation. The first involves solving the Maxwell equations in Coulomb gauge and then approximating the vector potential to remove retardation effects. The second approach approximates the Coulomb gauge equations themselves, then solves these exactly for the vector potential. There is no a priori reason that these should result in the same approximation. Here, the equivalence of these two approaches is investigated and a unified framework is provided in which to view the Darwin approximation. Darwin's original treatment is variational in nature, but subsequent applications of his ideas in the context of Vlasov's theory are not. We present here action principles for the Darwin approximation in the Vlasov context, and this serves as a consistency check on the use of the approximation in this setting.

  4. Closing the Achievement Gap between African American Children and their Caucasians Counterparts Using Collaboration Learning Setting

    ERIC Educational Resources Information Center

    Mubenga, Pascal T.

    2006-01-01

    The underachievement of a large and growing scale of African American children is nothing short of national crisis, according to Haycock (2001) in her research on closing the achievement gap. Haycock indicates that by the year 2010, Black and Hispanics will compromise approximately fifty percent of the school population. This is an alarming…

  5. The Experiences of African American Physical Education Teacher Candidates at Secondary Urban Schools

    ERIC Educational Resources Information Center

    Sato, Takahiro; Fisette, Jennifer; Walton, Theresa

    2013-01-01

    Presently, most physical education teachers in the United States are White Americans and from middle class families. In fact, 83% of all teachers in public schools are White Americans, whereas approximately 10% of all African American teachers are representative of all teachers in the United States. A student might feel cultural dissonance that…

  6. Discovering Africa through Internet-Based Geographic Information Systems: A Pan-African Summit Simulation

    ERIC Educational Resources Information Center

    Milson, Andrew J.; Gilbert, Kathleen M.; Earle, Brian D.

    2007-01-01

    In the United States, people get very little news about Africa, and what news they do get is about war or famine, with little historical information or context. In this article, the authors describe how they developed and implemented a Pan-African Summit simulation project in order to give their approximately 100, 9th-grade students (in five World…

  7. Antecedents and Consequences of Psychiatric Disorders in African-American Adolescents

    ERIC Educational Resources Information Center

    Jin, Run; Ge, Xiaojia; Brody, Gene H.; Simons, Ronald L.; Cutrona, Carolyn E.; Gibbons, Frederick X.

    2008-01-01

    This study included three waves of data, collected from approximately 890 African-American children and their families. Antecedents and consequences of psychiatric disorders among this population were examined. Children's temperament, pubertal timing, and experience of stressful life events were tested as antecedents of psychiatric disorders.…

  8. HIV misconceptions associated with condom use among black South Africans: an exploratory study

    PubMed Central

    Bogart, Laura M; Skinner, Donald; Weinhardt, Lance S; Glasman, Laura; Sitzler, Cheryl; Toefy, Yoesrie; Kalichman, Seth C

    2011-01-01

    In South Africa, approximately 20% of 15–49-year-olds are infected with HIV. Among black South Africans, high levels of HIV/AIDS misconceptions (e.g. HIV is manufactured by whites to reduce the black African population; AIDS is caused by supernatural forces or witchcraft) may be barriers to HIV prevention. We conducted a cross-sectional study of 150 young, black adults (aged 18–26; 56% males) visiting a public clinic for sexually transmitted infections, to investigate whether HIV/AIDS misconceptions were related to low condom use in main partner relationships. We assessed agreement with HIV/AIDS misconceptions relating to the supernatural (e.g. witchcraft as a cause of HIV) and to genocide (e.g. the withholding of a cure). In multivariate models, agreement that ‘Witchcraft plays a role in HIV transmission’ was significantly related to less positive attitudes about condoms, less belief in condom effectiveness for HIV prevention, and lower intentions to use condoms among men. The belief that ‘Vitamins and fresh fruits and vegetables can cure AIDS’ was associated with lower intentions among men to use condoms. Women who endorsed the belief linking HIV to witchcraft had a higher likelihood of unprotected sex with a main partner, whereas women who endorsed the belief that a cure for AIDS was being withheld had a lower likelihood of having had unprotected sex. Knowledge about distinct types of HIV/AIDS misconceptions and their correlates can help in the design of culturally appropriate HIV-prevention messages that address such beliefs. PMID:21804784

  9. Simultaneous observations of ionospheric irregularities in the African low-latitude region

    NASA Astrophysics Data System (ADS)

    Ngwira, Chigomezyo M.; Seemala, Gopi K.; Bosco Habarulema, John

    2013-05-01

    Ionospheric storms represent large global disturbances of the ionospheric F-region electron density in response to geomagnetic storms. This study investigates the ionospheric response during a minor geomagnetic storm that occurred on 13-15 September 2004. In particular, we use total electron content (TEC) measurements (rate of TEC change, ROT) to examine the presence of ionospheric irregularities over four low-latitude stations in the African sector, a region that has been less studied. Ionospheric irregularities are known to cause fading and phase fluctuation of L-band radio navigation signals such as those used by the Global Navigation Satellite Systems (GNSS), and are a common feature in the equatorial and low-latitude ionosphere. In the present study, the storm began with a sudden commencement at approximately 20:00 UT on 13 September, while the peak of the main phase occurred on 14 September with an SYM-H index value around -59 nT. On 13 September, the storm did not appear to hinder the development of irregularities as they were observed over all the stations. In contrast, irregularities were rarely observed at two of the 4 stations under study and were absent over the other two stations on 14 September. The DSMP F15 satellite post-sunset flight over the African region observed deep density depletions on 13 September that can be associated with the presence of ionospheric plasma bubble irregularities. Furthermore, an analysis of ΔH (horizontal geomagnetic component corrected for ring current effects) shows that there was a strong positive ΔH perturbation observed in the post-sunset hours on 13 September, which suggests the presence of an eastward penetration electric field, while a negative perturbation of ΔH, which is associated with the equatorial counter-electrojet, was observed on 14 September.

  10. Approximations of distant retrograde orbits for mission design

    NASA Technical Reports Server (NTRS)

    Hirani, Anil N.; Russell, Ryan P.

    2006-01-01

    Distant retrograde orbits (DROs) are stable periodic orbit solutions of the equations of motion in the circular restricted three body problem. Since no closed form expressions for DROs are known, we present methods for approximating a family of planar DROs for an arbitrary, fixed mass ratio. Furthermore we give methods for computing the first and second derivatives of the position and velocity with respect to the variables that parameterize the family. The approximation and derivative methods described allow a mission designer to target specific DROs or a range of DROs with no regard to phasing in contrast to the more limited case of targeting a six-state only.

  11. African-American Children's Stories.

    ERIC Educational Resources Information Center

    Nichols, Patricia C.

    Examination of representative stories told by black American children of West African descent in South Carolina shows that specific cultural motifs have been preserved in the oral tradition of black communities. Typical stories are tales of the supernatural, such as the Hag story about mortals who shed their skin at night to do evil deeds.…

  12. African American Men in College

    ERIC Educational Resources Information Center

    Cuyjet, Michael J., Ed.

    2006-01-01

    This book is a much-needed resource that includes examples of real-world programs and activities to enhance academic success in the college environment for African American men. The examples are collected from a variety of institutions across the country. With contributions from leading practitioners and scholars in the field, this book explores…

  13. Vitamin D and African Americans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vitamin D insufficiency is more prevalent among African Americans than other Americans and, in North America, most young, healthy blacks do not achieve optimal 25-hydroxyvitamin D [25(OH)D] concentrations at any time of the year. This is primarily due to the fact that pigmentation reduces vitamin D...

  14. Classic African American Children's Literature

    ERIC Educational Resources Information Center

    McNair, Jonda C.

    2010-01-01

    The purpose of this article is to assert that there are classic African American children's books and to identify a sampling of them. The author presents multiple definitions of the term classic based on the responses of children's literature experts and relevant scholarship. Next, the manner in which data were collected and analyzed in regard to…

  15. Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations.

    PubMed

    Peng, Degao; Yang, Yang; Zhang, Peng; Yang, Weitao

    2014-12-01

    In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N(4)). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as ⟨Ŝ(2)⟩ are also developed and tested. PMID:25481124

  16. Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations

    SciTech Connect

    Peng, Degao; Yang, Yang; Zhang, Peng; Yang, Weitao

    2014-12-07

    In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N{sup 4}). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as 〈S{sup ^2}〉 are also developed and tested.

  17. Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations

    NASA Astrophysics Data System (ADS)

    Peng, Degao; Yang, Yang; Zhang, Peng; Yang, Weitao

    2014-12-01

    In this article, we develop systematically second random phase approximations (RPA) and Tamm-Dancoff approximations (TDA) of particle-hole and particle-particle channels for calculating molecular excitation energies. The second particle-hole RPA/TDA can capture double excitations missed by the particle-hole RPA/TDA and time-dependent density-functional theory (TDDFT), while the second particle-particle RPA/TDA recovers non-highest-occupied-molecular-orbital excitations missed by the particle-particle RPA/TDA. With proper orbital restrictions, these restricted second RPAs and TDAs have a formal scaling of only O(N4). The restricted versions of second RPAs and TDAs are tested with various small molecules to show some positive results. Data suggest that the restricted second particle-hole TDA (r2ph-TDA) has the best overall performance with a correlation coefficient similar to TDDFT, but with a larger negative bias. The negative bias of the r2ph-TDA may be induced by the unaccounted ground state correlation energy to be investigated further. Overall, the r2ph-TDA is recommended to study systems with both single and some low-lying double excitations with a moderate accuracy. Some expressions on excited state property evaluations, such as < hat{S}2rangle are also developed and tested.

  18. Developing anatomical terms in an African language.

    PubMed

    Madzimbamuto, Farai Daniel

    2012-03-01

    Clinical and technical information imparted in most African languages involves inexact terminology and code switching, so it lacks the explanatory power characterised by the English language. African languages are absent in the tertiary science education environment and forums where African scientists could present scientific material in the medium of African languages. This limits the development of African languages in the scientific domain. There has recently been a trend in several African languages to develop and intellectualise them, especially in the field of medical sciences. The ChiShona language is used to explore the ability of an African language to develop new terminology, to name the vertebral skeleton and describe it scientifically. It uses word compounding to demonstrate terminology development. ChiShona has similarities with several hundred other Bantu languages in East, Central and Southern Africa. Advancing this language can promote similar developments in others, making them more explanatory for the lay public and health professionals. PMID:22380900

  19. Creating a segregated medical profession: African American physicians and organized medicine, 1846-1910.

    PubMed

    Baker, Robert B; Washington, Harriet A; Olakanmi, Ololade; Savitt, Todd L; Jacobs, Elizabeth A; Hoover, Eddie; Wynia, Matthew K; Blanchard, Janice; Boulware, L Ebony; Braddock, Clarence; Corbie-Smith, Giselle; Crawley, LaVera; LaVeist, Thomas A; Maxey, Randall; Mills, Charles; Moseley, Kathryn L; Williams, David R

    2009-06-01

    An independent panel of experts, convened by the American Medical Association (AMA) Institute for Ethics, analyzed the roots of the racial divide within American medical organizations. In this, the first of a 2-part report, we describe 2 watershed moments that helped institutionalize the racial divide. The first occurred in the 1870s, when 2 medical societies from Washington, DC, sent rival delegations to the AMA's national meetings: an all-white delegation from a medical society that the US courts and Congress had formally censured for discriminating against black physicians; and an integrated delegation from a medical society led by physicians from Howard University. Through parliamentary maneuvers and variable enforcement of credentialing standards, the integrated delegation was twice excluded from the AMA's meetings, while the all-white society's delegations were admitted. AMA leaders then voted to devolve the power to select delegates to state societies, thereby accepting segregation in constituent societies and forcing African American physicians to create their own, separate organizations. A second watershed involved AMA-promoted educational reforms, including the 1910 Flexner report. Straightforwardly applied, the report's population-based criterion for determining the need for phySicians would have recommended increased training of African American physicians to serve the approximately 9 million African Americans in the segregated south. Instead, the report recommended closing all but 2 African American medical schools, helping to cement in place an African American educational system that was separate, unequal, and destined to be insufficient to the needs of African Americans nationwide. PMID:19585918

  20. HIV stigma and discrimination in medical settings: stories from African women in New Zealand.

    PubMed

    Cannon Poindexter, Cynthia

    2013-01-01

    Recent changes in New Zealand's HIV and immigration situations have sparked a need to understand the experiences of HIV-positive African newcomers there. Here a narrative lens was brought to a previous qualitative study to harvest stories about discrimination in medical settings in New Zealand, told by four HIV-positive African women. Despite describing positive experiences with specialist HIV providers, their accounts shed light on weaknesses within the health care system regarding the rights and treatment of immigrants living with HIV. Participants reported inappropriate use of universal precautions, violations of confidentiality rights, discriminatory comments about Africans or persons with HIV, and misinformation about HIV transmission. Interventions must include enforcement of The Privacy Law and consistent training and monitoring of employee behavior in health care organizations. PMID:24028736

  1. Approximate Analysis of Semiconductor Laser Arrays

    NASA Technical Reports Server (NTRS)

    Marshall, William K.; Katz, Joseph

    1987-01-01

    Simplified equation yields useful information on gains and output patterns. Theoretical method based on approximate waveguide equation enables prediction of lateral modes of gain-guided planar array of parallel semiconductor lasers. Equation for entire array solved directly using piecewise approximation of index of refraction by simple functions without customary approximation based on coupled waveguid modes of individual lasers. Improved results yield better understanding of laser-array modes and help in development of well-behaved high-power semiconductor laser arrays.

  2. Constructive approximate interpolation by neural networks

    NASA Astrophysics Data System (ADS)

    Llanas, B.; Sainz, F. J.

    2006-04-01

    We present a type of single-hidden layer feedforward neural networks with sigmoidal nondecreasing activation function. We call them ai-nets. They can approximately interpolate, with arbitrary precision, any set of distinct data in one or several dimensions. They can uniformly approximate any continuous function of one variable and can be used for constructing uniform approximants of continuous functions of several variables. All these capabilities are based on a closed expression of the networks.

  3. Visual nesting impacts approximate number system estimation.

    PubMed

    Chesney, Dana L; Gelman, Rochel

    2012-08-01

    The approximate number system (ANS) allows people to quickly but inaccurately enumerate large sets without counting. One popular account of the ANS is known as the accumulator model. This model posits that the ANS acts analogously to a graduated cylinder to which one "cup" is added for each item in the set, with set numerosity read from the "height" of the cylinder. Under this model, one would predict that if all the to-be-enumerated items were not collected into the accumulator, either the sets would be underestimated, or the misses would need to be corrected by a subsequent process, leading to longer reaction times. In this experiment, we tested whether such miss effects occur. Fifty participants judged numerosities of briefly presented sets of circles. In some conditions, circles were arranged such that some were inside others. This circle nesting was expected to increase the miss rate, since previous research had indicated that items in nested configurations cannot be preattentively individuated in parallel. Logically, items in a set that cannot be simultaneously individuated cannot be simultaneously added to an accumulator. Participants' response times were longer and their estimations were lower for sets whose configurations yielded greater levels of nesting. The level of nesting in a display influenced estimation independently of the total number of items present. This indicates that miss effects, predicted by the accumulator model, are indeed seen in ANS estimation. We speculate that ANS biases might, in turn, influence cognition and behavior, perhaps by influencing which kinds of sets are spontaneously counted. PMID:22810562

  4. Piecewise linear approximation for hereditary control problems

    NASA Technical Reports Server (NTRS)

    Propst, Georg

    1990-01-01

    This paper presents finite-dimensional approximations for linear retarded functional differential equations by use of discontinuous piecewise linear functions. The approximation scheme is applied to optimal control problems, when a quadratic cost integral must be minimized subject to the controlled retarded system. It is shown that the approximate optimal feedback operators converge to the true ones both in the case where the cost integral ranges over a finite time interval, as well as in the case where it ranges over an infinite time interval. The arguments in the last case rely on the fact that the piecewise linear approximations to stable systems are stable in a uniform sense.

  5. The Role of African topography in the South Asian Monsoon

    NASA Astrophysics Data System (ADS)

    Wei, H. H.; Bordoni, S.

    2014-12-01

    The Somali cross-equatorial jet is estimated to contribute up to half of the mass flux crossing the equator during the Asian monsoon season. Previous studies have argued that the Somali jet is strengthened by the East African Highlands, which act as a wall and accelerate the flow (e.g., Krishnamurti et al. 1976, Sashegyi and Geisler 1987). Besides, observational studies have shown a positive correlation between the strength of the Somali jet and the South Asian Monsoon (SAM) precipitation (e.g., Findlater 1969, Halpern and Woiceshyn 2001). These imply that the existence of the topography would relate to a stronger SAM. However, in a more recent study, Chakraborty et al. (2002) found that if the African topography is removed in a comprehensive general circulation model (GCM), the SAM strengthens. In this study, we use the GFDL AM2.1 GCM to conduct experiments with and without topography in Africa, to further examine its influence on the cross-equatorial Somali jet and the SAM. We find that when the African topography is removed, the SAM precipitation increases, consistent with the results in Chakraborty et al. (2002). Interestingly, our results also show that the cross-equatorial Somali jet does weaken in the absence of the African topography, in agreement with previous studies. The moisture budget shows that the increase in precipitation in the no-African topography experiment is primarily due to stronger wind convergence. The dynamics of the cross-equatorial Somali jet is investigated within the framework of the Potential Vorticity (PV) budget, showing the contribution of the changes in friction and diabatic heating to the circulation as the topography is removed. A backward trajectory analysis is also conducted to further examine the influence of topography on both the material tendencies of the PV budget and trajectories of parcels reaching the Indian subcontinent.

  6. Successful African American women in science: A narrative inquiry

    NASA Astrophysics Data System (ADS)

    Petty, Cailisha L.

    This study used narrative inquiry as a methodology to explore the lived experiences of five African American women in science across the academic spectrum, from doctoral candidate to full professor. The research questions guiding the inquiry included one overarching question and three sub-questions: What are the lifestories of successful African American women in science?; a) How do successful African American women in science define themselves?; b) What have been the facilitators and barriers encountered by successful African American women in science?; and c) What have been the systems of support for African American women in science? The study was theoretically positioned within the frameworks of Critical Race Theory and Black Feminist Thought. The two theories were used to guide all aspects of the study including methodology, data collection, and analysis. Data included eleven 40-60 minute semi-structured interview transcripts as well as the participants' Curriculum Vitae. The study design and data analysis were built upon Clandinin and Connelly's (2000) and Clandinin's (2006) model of narrative inquiry which explores narratives as a means to understand experience. Analysis and interpretation created three dominant narratives: Scientific Beginnings, An Unexpected Journey, and Lift as You Climb. Each narrative set explores multiple stories that describe storylines which aligned with the participants' goals of who they were and who they were becoming as scientists; and, storylines of tension which ran counter to the women's goals and aspirations. Barriers and support systems are revealed, as well as the meanings the participants made of their experiences and how it affected their lives.

  7. Coping with Racial Discrimination: Assessing the Vulnerability of African Americans and the Mediated Moderation of Psychosocial Resources

    PubMed Central

    Miller, Byron; Rote, Sunshine M.; Keith, Verna M.

    2014-01-01

    Research demonstrates that the mental health of African Americans is negatively affected by discrimination, but few studies have investigated the effects of racial discrimination specifically and whether these effects vary by poverty and education levels. Using a sample of 3,372 African Americans from the National Survey of American Life (NSAL), we find a positive relationship between racial discrimination and depressive symptoms, with both lifetime and daily racial discrimination being more salient for depressive symptoms among impoverished African Americans than those living above 200% of the poverty line. Evaluating mediated moderation models, we also find that the conditional effects of socioeconomic status are mediated by poor African Americans’ having fewer psychosocial resources. Namely, lower levels of mastery are influential in accounting for poor African Americans’ greater vulnerability to both daily and lifetime discrimination. The findings highlight the importance of examining specific reasons for discrimination as well as mediated moderation in future research. PMID:25419483

  8. Racial Discrimination, John Henryism, and Depression Among African Americans

    PubMed Central

    Hudson, Darrell L.; Neighbors, Harold W.; Geronimus, Arline T.; Jackson, James S.

    2016-01-01

    Evidence from previous studies indicates that racial discrimination is significantly associated with depression and that African Americans with higher levels of socioeconomic status (SES) report greater exposure to racial discrimination compared to those with lower SES levels. Coping strategies could alter the relationship between racial discrimination and depression among African Americans. This study first examined whether greater levels of SES were associated with increased reports of racial discrimination and ratings of John Henryism, a measure of high-effort coping, among African Americans. Second, we examined whether high-effort coping moderated the relationship between racial discrimination and depression. Data were drawn from the National Survey of American Life Reinterview (n = 2,137). Analyses indicated that greater levels of education were positively associated with racial discrimination (p < .001) and increased levels of racial discrimination were positively related to depression (p < .001), controlling for all sociodemographic factors. Greater levels of John Henryism were associated with increased odds of depression but there was no evidence to suggest that the relationship between discrimination and depression was altered by the effects of John Henryism. PMID:16259481

  9. Spline approximations for nonlinear hereditary control systems

    NASA Technical Reports Server (NTRS)

    Daniel, P. L.

    1982-01-01

    A sline-based approximation scheme is discussed for optimal control problems governed by nonlinear nonautonomous delay differential equations. The approximating framework reduces the original control problem to a sequence of optimization problems governed by ordinary differential equations. Convergence proofs, which appeal directly to dissipative-type estimates for the underlying nonlinear operator, are given and numerical findings are summarized.

  10. Quirks of Stirling's Approximation

    ERIC Educational Resources Information Center

    Macrae, Roderick M.; Allgeier, Benjamin M.

    2013-01-01

    Stirling's approximation to ln "n"! is typically introduced to physical chemistry students as a step in the derivation of the statistical expression for the entropy. However, naive application of this approximation leads to incorrect conclusions. In this article, the problem is first illustrated using a familiar "toy…

  11. Taylor approximations of multidimensional linear differential systems

    NASA Astrophysics Data System (ADS)

    Lomadze, Vakhtang

    2016-06-01

    The Taylor approximations of a multidimensional linear differential system are of importance as they contain a complete information about it. It is shown that in order to construct them it is sufficient to truncate the exponential trajectories only. A computation of the Taylor approximations is provided using purely algebraic means, without requiring explicit knowledge of the trajectories.

  12. Approximation for nonresonant beam target fusion reactivities

    SciTech Connect

    Mikkelsen, D.R.

    1988-11-01

    The beam target fusion reactivity for a monoenergetic beam in a Maxwellian target is approximately evaluated for nonresonant reactions. The approximation is accurate for the DD and TT fusion reactions to better than 4% for all beam energies up to 300 keV and all ion temperatures up to 2/3 of the beam energy. 12 refs., 1 fig., 1 tab.

  13. Computing Functions by Approximating the Input

    ERIC Educational Resources Information Center

    Goldberg, Mayer

    2012-01-01

    In computing real-valued functions, it is ordinarily assumed that the input to the function is known, and it is the output that we need to approximate. In this work, we take the opposite approach: we show how to compute the values of some transcendental functions by approximating the input to these functions, and obtaining exact answers for their…

  14. Diagonal Pade approximations for initial value problems

    SciTech Connect

    Reusch, M.F.; Ratzan, L.; Pomphrey, N.; Park, W.

    1987-06-01

    Diagonal Pade approximations to the time evolution operator for initial value problems are applied in a novel way to the numerical solution of these problems by explicitly factoring the polynomials of the approximation. A remarkable gain over conventional methods in efficiency and accuracy of solution is obtained. 20 refs., 3 figs., 1 tab.

  15. Inversion and approximation of Laplace transforms

    NASA Technical Reports Server (NTRS)

    Lear, W. M.

    1980-01-01

    A method of inverting Laplace transforms by using a set of orthonormal functions is reported. As a byproduct of the inversion, approximation of complicated Laplace transforms by a transform with a series of simple poles along the left half plane real axis is shown. The inversion and approximation process is simple enough to be put on a programmable hand calculator.

  16. An approximation for inverse Laplace transforms

    NASA Technical Reports Server (NTRS)

    Lear, W. M.

    1981-01-01

    Programmable calculator runs simple finite-series approximation for Laplace transform inversions. Utilizing family of orthonormal functions, approximation is used for wide range of transforms, including those encountered in feedback control problems. Method works well as long as F(t) decays to zero as it approaches infinity and so is appliable to most physical systems.

  17. Linear radiosity approximation using vertex radiosities

    SciTech Connect

    Max, N. Lawrence Livermore National Lab., CA ); Allison, M. )

    1990-12-01

    Using radiosities computed at vertices, the radiosity across a triangle can be approximated by linear interpolation. We develop vertex-to-vertex form factors based on this linear radiosity approximation, and show how they can be computed efficiently using modern hardware-accelerated shading and z-buffer technology. 9 refs., 4 figs.

  18. Approximation theory for boundary layer suction through individual slits

    NASA Technical Reports Server (NTRS)

    Walz, A.

    1979-01-01

    The basic concepts of influencing boundary layers are summarized, especially the prevention of flow detachment and the reduction of frictional resistance. A mathematical analysis of suction through a slit is presented with two parameters, for thickness and for shape of the boundary layer, being introduced to specify the flow's velocity profile behind the slit. An approximation of the shape parameter produces a useful formula, which can be used to determine the most favorable position of the slit. An aerodynamic example is given.

  19. CYP2D6 phenotype-genotype relationships in African-Americans and Caucasians in Los Angeles.

    PubMed

    Leathart, J B; London, S J; Steward, A; Adams, J D; Idle, J R; Daly, A K

    1998-12-01

    CYP2D6 genotyping (CYP2D6*3, CYP2D6*4, CYP2D6*5, CYP2D6*13, CYP2D6*16 alleles and gene duplications) was previously performed on 1053 Caucasian and African-American lung cancer cases and control individuals and no significant difference in allele frequencies between cases and control individuals detected. We have carried out additional genotyping (CYP2D6*6, CYP2D6*7, CYP2D6*8, CYP2D6*9, CYP2D6*10, CYP2D6*17 alleles) and debrisoquine phenotyping on subgroups from this study to assess phenotype-genotype relationships. African-Americans showed significant differences from Caucasians with respect to frequency of defective CYP2D6 alleles, particularly CYP2D6*4 and CYP2D6*5. The CYP2D6*17 allele occurred at a frequency of 0.26 among 87 African-Americans and appeared to explain higher average metabolic ratios among African-Americans compared with Caucasians. CYP2D6*6, CYP2D6*8, CYP2D6*9 and CYP2D6*10 were rare in both ethnic groups but explained approximately 40% of higher than expected metabolic ratios among extensive metabolizers. Among individuals phenotyped with debrisoquine, 32 out of 359 were in the poor metabolizer range with 24 of these (75%) also showing two defective CYP2D6 alleles. Additional single strand conformational polymorphism analysis screening of samples showing large phenotype-genotype discrepancies resulted in the detection of three novel polymorphisms. If subjects taking potentially interfering drugs were excluded, this additional screening enabled the positive identification of 88% of phenotypic poor metabolizers by genotyping. This sensitivity was comparable with that of phenotyping, which identified 90% of those with two defective alleles as poor metabolizers. PMID:9918137

  20. Approximating maximum clique with a Hopfield network.

    PubMed

    Jagota, A

    1995-01-01

    In a graph, a clique is a set of vertices such that every pair is connected by an edge. MAX-CLIQUE is the optimization problem of finding the largest clique in a given graph and is NP-hard, even to approximate well. Several real-world and theory problems can be modeled as MAX-CLIQUE. In this paper, we efficiently approximate MAX-CLIQUE in a special case of the Hopfield network whose stable states are maximal cliques. We present several energy-descent optimizing dynamics; both discrete (deterministic and stochastic) and continuous. One of these emulates, as special cases, two well-known greedy algorithms for approximating MAX-CLIQUE. We report on detailed empirical comparisons on random graphs and on harder ones. Mean-field annealing, an efficient approximation to simulated annealing, and a stochastic dynamics are the narrow but clear winners. All dynamics approximate much better than one which emulates a "naive" greedy heuristic. PMID:18263357

  1. Approximate error conjugation gradient minimization methods

    DOEpatents

    Kallman, Jeffrey S

    2013-05-21

    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  2. Exploring How African American Males from an Urban Community Navigate the Interracial and Intra-Racial Dimensions of Their Experiences at an Urban Jesuit High School

    ERIC Educational Resources Information Center

    Simmons, Robert W., III

    2012-01-01

    African American males from urban communities have been attending Jesuit high schools in urban spaces for many years, yet little to no literature exists that explores their experiences while attending these elite private schools. This qualitative study of 10 African American males from an urban community attending a similarly positioned Jesuit…

  3. Racial Barrier Socialization and the Well-Being of African American Adolescents: The Moderating Role of Mother-Adolescent Relationship Quality

    ERIC Educational Resources Information Center

    Cooper, Shauna M.; McLoyd, Vonnie C.

    2011-01-01

    Racial socialization has been suggested as an important factor in helping African American adolescents cope effectively with racism and discrimination. Although multiple studies have reported a positive link between racial pride socialization and psychological adjustment among African American youth, assessments of the association between…

  4. Diagnosed but Not Defeated: The Experiences of African-American Males with Past Histories of Enrollment in Special Education Who Successfully Attend Community College

    ERIC Educational Resources Information Center

    Strickland-Dixon, Kennedi

    2013-01-01

    African-American males are disappearing at alarming rates before our eyes through racially driven practices that secure their position in the penal system and special education. Though many scholars in the field of education have highlighted alarming rates of incarceration and overrepresentation in special education for African-American males,…

  5. Recurrent sebaceous carcinoma in an African hedgehog (Atelerix albiventris).

    PubMed

    Kim, Hyung-Jin; Kim, Yong-Baek; Park, Jun-Won; Oh, Won-Seok; Kim, Eun-Ok; Lim, Byoung-Yong; Kim, Dae-Yong

    2010-07-01

    A 1.5-year-old intact male African hedgehog (Atelerix albiventris) was presented with a firm, non-movable subcutaneous mass on ventral chest area. Microscopically, the tumor was un-encapsulated, invasive up to the muscle layer, and composed of highly pleomorphic polygonal cells arranged in variably-sized lobules. The neoplastic cells had abundant cytoplasm with vacuolation and a large pleomorphic nucleus with prominent nucleoli. Mitotic figures were frequently observed with atypical mitoses. Immunohistochemically, the neoplastic cells were strongly positive for cytokeratin, but negative for vimentin. Based on these findings, a diagnosis of sebaceous carcinoma was made. Three months after the surgery, a recurrent mass was found at the surgical site. On necropsy, the mass has penetrated the underlying intercostal musculature, without metastasis to distant organs. This is the first report of a sebaceous carcinoma in an African hedgehog. PMID:20215722

  6. Mentoring: a supporting act for African American students and faculty.

    PubMed

    Fox, O H; Broome, B S

    2001-01-01

    Part of the reason for the low numbers of African-America nurses is related to nursing student attrition. One approach described to help students to successfully complete educational objectives is mentoring. Mentoring is a supportive act for both minority students and faculty. Although numerous definitions of mentoring exist it is recognized that a mentor can be a role model, confidante, friend, and support system. Mentors may be the passageway into the work force or a bypass around the many obstacles that impede success. Because of the limited African American faculty available, many are overworked and may never reach full potential, contributing to the problem of limited minority nursing faculty available to institutions of higher learning. This article describes the markers of both poor and positive mentoring universities. PMID:11760475

  7. Digital expression among urban, low-income African American adolescents.

    PubMed

    Baker, Christina M; Staiano, Amanda E; Calvert, Sandra L

    2011-01-01

    Digital production is a means through which African American adolescents communicate and express their experiences with peers. This study examined the content and the form of the digital productions of 24 urban, low-income African American adolescents who attended a summer academic program. The content of student digital productions focused on academic experiences and friendships. Their production styles revealed that youth used perceptually salient production features, such as rapid scene changes and loud rap music. The results suggest that when placed in a supportive, academic environment and provided with digital production resources, students who traditionally face barriers due to cultural and economic inequalities digitally express to their peers an interest in academics and positive peer relationships, and that these youth communicate their experiences through a shared production style that reflects their broader cultural experiences. PMID:21910270

  8. Parenting Needs of Urban, African American Fathers.

    PubMed

    Smith, Tyler K; Tandon, S Darius; Bair-Merritt, Megan H; Hanson, Janice L

    2015-07-01

    Fathers play a critical role in children's development; similarly, fatherhood positively affects men's health. Among the larger population of fathers relatively little is known about the parenting knowledge of urban, African American fathers. Focusing on urban, African American fathers, the objectives of this study were to (1) understand the primary sources from which fathers learn about parenting, (2) determine where and how fathers prefer to receive future parenting education, and (3) explore the information perceived as most valuable to fathers and how this compares with the recommended anticipatory guidance (Bright Futures-based) delivered during well visits. Five focus groups, with a total of 21 participants, were conducted with urban fathers at a community-based organization. Study eligibility included being more than 18 years old, English speaking, and having at least one child 0 to 5 years old. During the focus groups, fathers were asked where they received parenting information, how and where they preferred to receive parenting information, and what they thought about Bright Futures parenting guidelines. Fathers most commonly described receiving parenting information from their own relatives rather than from their child's health care provider. Most fathers preferred to learn parenting from a person rather than a technology-based source and expressed interest in learning more about parenting at community-based locations. Although fathers viewed health care providers' role as primarily teaching about physical health, they valued Bright Futures anticipatory guidance about parenting. Fathers valued learning about child rearing, health, and development. Augmenting physician counseling about Bright Futures with community-based parenting education may be beneficial for fathers. PMID:25147096

  9. The UCAR Africa Initiative: Enabling African Solutions to African Needs

    NASA Astrophysics Data System (ADS)

    Pandya, R.; Bruintjes, R.; Foote, B.; Heck, S.; Hermann, S.; Hoswell, L.; Konate, M.; Kucera, P.; Laing, A.; Lamptey, B.; Moncrieff, M.; Ramamurthy, M.; Roberts, R.; Spangler, T.; Traoré, A.; Yoksas, T.; Warner, T.

    2007-12-01

    The University Corporation for Atmospheric Research (UCAR) Africa Initiative (AI) is a coordinated effort aimed at building sustainable partnerships between UCAR and African institutions in order to pursue research and applications for the benefit of the African people. The initiative is based on four fundamental operating principles, concisely summarized by the overall philosophy of enabling African solutions to African needs. The four principles are: • Collaborate with African institutions • Focus on institutional capacity building and research support • Explore science research themes critical to Africa and important for the world • Leverage the research infrastructure in UCAR to add value These principles are realized in a set of pilot activities, chosen for their high probability of short-term results and ability to set the stage for longer-term collaboration. The three pilot activities are listed below. 1. A modest radar network and data-distribution system in Mali and Burkina Faso, including a data-sharing MOU between the Mail and Burkina Faso Weather Services. 2. A partnership among UCAR, the Ghana Meteorological Agency, and the Ghana university community to develop an operational Weather Research and Forecasting (WRF) model for West Africa. The output is used by researchers and operational forecasters in Africa. Model output is also part of a demonstration project that aims to allow humanitarian agencies to share geo-referenced information in Africa via a web portal. 3. A workshop in Ouagadougou, Burkina Faso from April 2-6, 2007, with the theme Improving Lives by Understanding Weather. The workshop, co-organized with Programme SAAGA and the Commité Permanent Inter-Etats de Lutte Contre la Sécheresse dans le Sahel (CILSS), included over 80 participants from 18 countries, and produced a set of recommendations for continued collaboration. Our presentation will provide an update of these pilot activities and point to future directions. Recognizing

  10. Interfacing Relativistic and Nonrelativistic Methods: A Systematic Sequence of Approximations

    NASA Technical Reports Server (NTRS)

    Dyall, Ken; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    A systematic sequence of approximations for the introduction of relativistic effects into nonrelativistic molecular finite-basis set calculations is described. The theoretical basis for the approximations is the normalized elimination of the small component (ESC) within the matrix representation of the modified Dirac equation. The key features of the normalized method are the retention of the relativistic metric and the ability to define a single matrix U relating the pseudo-large and large component coefficient matrices. This matrix is used to define a modified set of one- and two-electron integrals which have the same appearance as the integrals of the Breit-Pauli Hamiltonian. The first approximation fixes the ratios of the large and pseudo-large components to their atomic values, producing an expansion in atomic 4-spinors. The second approximation defines a local fine-structure constant on each atomic centre, which has the physical value for centres considered to be relativistic and zero for nonrelativistic centres. In the latter case, the 4-spinors are the positive-energy kinetic al ly-balanced solutions of the Levy-Leblond equation, and the integrals involving pseudo-large component basis functions on these centres, are set to zero. Some results are presented for test systems to illustrate the various approximations.

  11. Neighborhood Racial Composition, Racial Discrimination, and Depressive Symptoms in African Americans

    PubMed Central

    Lambert, Sharon F.; Evans, Michele K.; Zonderman, Alan B.

    2015-01-01

    While evidence indicates that experienced racial discrimination is associated with increased depressive symptoms for African Americans, there is little research investigating predictors of experienced racial discrimination. This paper examines neighborhood racial composition and sociodemographic factors as antecedents to experienced racial discrimination and resultant levels of depressive symptoms among African American adults. The sample included 505 socioeconomically-diverse African American adults from Baltimore, MD. Study data were obtained via self-report and geocoding of participant addresses based on 2010 census data. Study hypotheses were tested using multiple pathways within a longitudinal Structural Equation Model. Experienced racial discrimination was positively associated with age and sex such that older individuals and males experienced increased levels of racial discrimination. In addition, the percentage of White individuals residing in a neighborhood was positively associated with levels of experienced racial discrimination for African American neighborhood residents. Experienced racial discrimination was positively associated with later depressive symptoms. Neighborhood-level contextual factors such as neighborhood racial composition and individual differences in sociodemographic characteristics appear to play an important role in the experience of racial discrimination and the etiology of depression in African American adults. PMID:24969707

  12. Neighborhood racial composition, racial discrimination, and depressive symptoms in African Americans.

    PubMed

    English, Devin; Lambert, Sharon F; Evans, Michele K; Zonderman, Alan B

    2014-12-01

    While evidence indicates that experienced racial discrimination is associated with increased depressive symptoms for African Americans, there is little research investigating predictors of experienced racial discrimination. This paper examines neighborhood racial composition and sociodemographic factors as antecedents to experienced racial discrimination and resultant levels of depressive symptoms among African American adults. The sample included 505 socioeconomically-diverse African American adults from Baltimore, MD. Study data were obtained via self-report and geocoding of participant addresses based on 2010 census data. Study hypotheses were tested using multiple pathways within a longitudinal Structural Equation Model. Experienced racial discrimination was positively associated with age and sex such that older individuals and males experienced increased levels of racial discrimination. In addition, the percentage of White individuals residing in a neighborhood was positively associated with levels of experienced racial discrimination for African American neighborhood residents. Experienced racial discrimination was positively associated with later depressive symptoms. Neighborhood-level contextual factors such as neighborhood racial composition and individual differences in sociodemographic characteristics appear to play an important role in the experience of racial discrimination and the etiology of depression in African American adults. PMID:24969707

  13. Multigene phylogenetics reveals temporal diversification of major African malaria vectors.

    PubMed

    Kamali, Maryam; Marek, Paul E; Peery, Ashley; Antonio-Nkondjio, Christophe; Ndo, Cyrille; Tu, Zhijian; Simard, Frederic; Sharakhov, Igor V

    2014-01-01

    The major vectors of malaria in sub-Saharan Africa belong to subgenus Cellia. Yet, phylogenetic relationships and temporal diversification among African mosquito species have not been unambiguously determined. Knowledge about vector evolutionary history is crucial for correct interpretation of genetic changes identified through comparative genomics analyses. In this study, we estimated a molecular phylogeny using 49 gene sequences for the African malaria vectors An. gambiae, An. funestus, An. nili, the Asian malaria mosquito An. stephensi, and the outgroup species Culex quinquefasciatus and Aedes aegypti. To infer the phylogeny, we identified orthologous sequences uniformly distributed approximately every 5 Mb in the five chromosomal arms. The sequences were aligned and the phylogenetic trees were inferred using maximum likelihood and neighbor-joining methods. Bayesian molecular dating using a relaxed log normal model was used to infer divergence times. Trees from individual genes agreed with each other, placing An. nili as a basal clade that diversified from the studied malaria mosquito species 47.6 million years ago (mya). Other African malaria vectors originated more recently, and independently acquired traits related to vectorial capacity. The lineage leading to An. gambiae diverged 30.4 mya, while the African vector An. funestus and the Asian vector An. stephensi were the most closely related sister taxa that split 20.8 mya. These results were supported by consistently high bootstrap values in concatenated phylogenetic trees generated individually for each chromosomal arm. Genome-wide multigene phylogenetic analysis is a useful approach for discerning historic relationships among malaria vectors, providing a framework for the correct interpretation of genomic changes across species, and comprehending the evolutionary origins of this ubiquitous and deadly insect-borne disease. PMID:24705448

  14. Genome-wide patterns of population structure and admixture in West Africans and African Americans.

    PubMed

    Bryc, Katarzyna; Auton, Adam; Nelson, Matthew R; Oksenberg, Jorge R; Hauser, Stephen L; Williams, Scott; Froment, Alain; Bodo, Jean-Marie; Wambebe, Charles; Tishkoff, Sarah A; Bustamante, Carlos D

    2010-01-12

    Quantifying patterns of population structure in Africans and African Americans illuminates the history of human populations and is critical for undertaking medical genomic studies on a global scale. To obtain a fine-scale genome-wide perspective of ancestry, we analyze Affymetrix GeneChip 500K genotype data from African Americans (n = 365) and individuals with ancestry from West Africa (n = 203 from 12 populations) and Europe (n = 400 from 42 countries). We find that population structure within the West African sample reflects primarily language and secondarily geographical distance, echoing the Bantu expansion. Among African Americans, analysis of genomic admixture by a principal component-based approach indicates that the median proportion of European ancestry is 18.5% (25th-75th percentiles: 11.6-27.7%), with very large variation among individuals. In the African-American sample as a whole, few autosomal regions showed exceptionally high or low mean African ancestry, but the X chromosome showed elevated levels of African ancestry, consistent with a sex-biased pattern of gene flow with an excess of European male and African female ancestry. We also find that genomic profiles of individual African Americans afford personalized ancestry reconstructions differentiating ancient vs. recent European and African ancestry. Finally, patterns of genetic similarity among inferred African segments of African-American genomes and genomes of contemporary African populations included in this study suggest African ancestry is most similar to non-Bantu Niger-Kordofanian-speaking populations, consistent with historical documents of the African Diaspora and trans-Atlantic slave trade. PMID:20080753

  15. APPROXIMATING LIGHT RAYS IN THE SCHWARZSCHILD FIELD

    SciTech Connect

    Semerák, O.

    2015-02-10

    A short formula is suggested that approximates photon trajectories in the Schwarzschild field better than other simple prescriptions from the literature. We compare it with various ''low-order competitors'', namely, with those following from exact formulas for small M, with one of the results based on pseudo-Newtonian potentials, with a suitably adjusted hyperbola, and with the effective and often employed approximation by Beloborodov. Our main concern is the shape of the photon trajectories at finite radii, yet asymptotic behavior is also discussed, important for lensing. An example is attached indicating that the newly suggested approximation is usable—and very accurate—for practically solving the ray-deflection exercise.

  16. Detecting Gravitational Waves using Pade Approximants

    NASA Astrophysics Data System (ADS)

    Porter, E. K.; Sathyaprakash, B. S.

    1998-12-01

    We look at the use of Pade Approximants in defining a metric tensor for the inspiral waveform template manifold. By using this method we investigate the curvature of the template manifold and the number of templates needed to carry out a realistic search for a Gravitational Wave signal. By comparing this method with the normal use of Taylor Approximant waveforms we hope to show that (a) Pade Approximants are a superior method for calculating the inspiral waveform, and (b) the number of search templates needed, and hence computing power, is reduced.

  17. Alternative approximation concepts for space frame synthesis

    NASA Technical Reports Server (NTRS)

    Lust, R. V.; Schmit, L. A.

    1985-01-01

    A method for space frame synthesis based on the application of a full gamut of approximation concepts is presented. It is found that with the thoughtful selection of design space, objective function approximation, constraint approximation and mathematical programming problem formulation options it is possible to obtain near minimum mass designs for a significant class of space frame structural systems while requiring fewer than 10 structural analyses. Example problems are presented which demonstrate the effectiveness of the method for frame structures subjected to multiple static loading conditions with limits on structural stiffness and strength.

  18. Approximate knowledge compilation: The first order case

    SciTech Connect

    Val, A. del

    1996-12-31

    Knowledge compilation procedures make a knowledge base more explicit so as make inference with respect to the compiled knowledge base tractable or at least more efficient. Most work to date in this area has been restricted to the propositional case, despite the importance of first order theories for expressing knowledge concisely. Focusing on (LUB) approximate compilation, our contribution is twofold: (1) We present a new ground algorithm for approximate compilation which can produce exponential savings with respect to the previously known algorithm. (2) We show that both ground algorithms can be lifted to the first order case preserving their correctness for approximate compilation.

  19. Adiabatic approximation for nucleus-nucleus scattering

    SciTech Connect

    Johnson, R.C.

    2005-10-14

    Adiabatic approximations to few-body models of nuclear scattering are described with emphasis on reactions with deuterons and halo nuclei (frozen halo approximation) as projectiles. The different ways the approximation should be implemented in a consistent theory of elastic scattering, stripping and break-up are explained and the conditions for the theory's validity are briefly discussed. A formalism which links few-body models and the underlying many-body system is outlined and the connection between the adiabatic and CDCC methods is reviewed.

  20. Approximate Bruechner orbitals in electron propagator calculations

    SciTech Connect

    Ortiz, J.V.

    1999-12-01

    Orbitals and ground-state correlation amplitudes from the so-called Brueckner doubles approximation of coupled-cluster theory provide a useful reference state for electron propagator calculations. An operator manifold with hold, particle, two-hole-one-particle and two-particle-one-hole components is chosen. The resulting approximation, third-order algebraic diagrammatic construction [2ph-TDA, ADC (3)] and 3+ methods. The enhanced versatility of this approximation is demonstrated through calculations on valence ionization energies, core ionization energies, electron detachment energies of anions, and on a molecule with partial biradical character, ozone.

  1. Information geometry of mean-field approximation.

    PubMed

    Tanaka, T

    2000-08-01

    I present a general theory of mean-field approximation based on information geometry and applicable not only to Boltzmann machines but also to wider classes of statistical models. Using perturbation expansion of the Kullback divergence (or Plefka expansion in statistical physics), a formulation of mean-field approximation of general orders is derived. It includes in a natural way the "naive" mean-field approximation and is consistent with the Thouless-Anderson-Palmer (TAP) approach and the linear response theorem in statistical physics. PMID:10953246

  2. African American Therapists Working with African American Families: An Exploration of the Strengths Perspective in Treatment

    ERIC Educational Resources Information Center

    Bell-Tolliver, Laverne; Burgess, Ruby; Brock, Linda J.

    2009-01-01

    With the exception of Hill's (1971, 1999) work, historically much of the literature on African American families has focused more on pathology than strengths. This study used interviews with 30 African American psychotherapists, self-identified as employing a strengths perspective with African American families, to investigate which strengths they…

  3. Karla Holloway to Lead African and African-American Studies at Duke University.

    ERIC Educational Resources Information Center

    Hawkins, B. Denise

    1996-01-01

    The appointment of Karla F. C. Holloway, an African American woman, as director of the Duke University (North Carolina) African American Studies program is representative of an institutional effort to stabilize the program and to recruit African American scholars to the institution, across disciplines. During Holloway's interim directorship,…

  4. 75 FR 2844 - African Development Foundation, Board of Directors Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ...; ] AFRICAN DEVELOPMENT FOUNDATION African Development Foundation, Board of Directors Meeting Time: Tuesday, January 26, 2010, 8:30 a.m. to 1 p.m. Place: African Development Foundation, Conference Room, 1400...

  5. 75 FR 14418 - African Development Foundation, Board of Directors Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-25

    ...; ] AFRICAN DEVELOPMENT FOUNDATION African Development Foundation, Board of Directors Meeting Time: Tuesday, April 13, 2010, 9:30 a.m. to 1 p.m. Place: African Development Foundation, Conference Room, 1400...

  6. 75 FR 45600 - African Development Foundation, Board of Directors Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ...; ] AFRICAN DEVELOPMENT FOUNDATION African Development Foundation, Board of Directors Meeting Time: Tuesday, August 17, 2010, 8:30 a.m. to 1 p.m. Place: African Development Foundation, Conference Room, 1400...

  7. Cultural aspects of African American eating patterns.

    PubMed

    Airhihenbuwa, C O; Kumanyika, S; Agurs, T D; Lowe, A; Saunders, D; Morssink, C B

    1996-09-01

    The high mortality from diet-related diseases among African Americans strongly suggests a need to adopt diets lower in total fat, saturated fat and salt and higher in fiber. However, such changes would be contrary to some traditional African American cultural practices. Focus group interviews were used to explore cultural aspects of eating patterns among low- and middle-income African Americans recruited from an urban community in Pennsylvania. In total, 21 males and 32 females, aged 13-65+ years were recruited using a networking technique. Participants identified eating practices commonly attributed to African Americans and felt that these were largely independent of socioeconomic status. They were uncertain about links between African American eating patterns and African origins but clear about influences of slavery and economic disadvantage. The perception that African American food patterns were characteristically adaptive to external conditions, suggest that, for effective dietary change in African American communities, changes in the food availability will need to precede or take place in parallel with changes recommended to individuals. Cultural attitudes about where and with whom food is eaten emerged as being equivalent in importance to attitudes about specific foods. These findings emphasize the importance of continued efforts to identify ways to increase the relevance of cultural context and meanings in dietary counseling so that health and nutrition interventions are anchored in values as perceived, in this case, by African Americans. PMID:9395569

  8. Race, health, and the African Diaspora.

    PubMed

    Spigner, Clarence

    Health inequalities exist throughout the African Diaspora and are viewed in this article as largely color-coded. In developed, developing, and undeveloped nations today, "racial" stratification is consistently reflected in an inability to provide adequate health regardless of national policy or ideology. For instance, African Americans experience less than adequate health care very similar to Blacks in Britain, in spite of each nations differing health systems. Latin America's Africana Negra communities experience poorer health similar to Blacks throughout the Caribbean. The African continent itself is arguably the poorest on earth. A common history of racism correlates with health disparities across the African Diaspora. PMID:18364304

  9. Gentle Africanized bees on an oceanic island

    PubMed Central

    Rivera-Marchand, Bert; Oskay, Devrim; Giray, Tugrul

    2012-01-01

    Oceanic islands have reduced resources and natural enemies and potentially affect life history traits of arriving organisms. Among the most spectacular invasions in the Western hemisphere is that of the Africanized honeybee. We hypothesized that in the oceanic island Puerto Rico, Africanized bees will exhibit differences from the mainland population such as for defensiveness and other linked traits. We evaluated the extent of Africanization through three typical Africanized traits: wing size, defensive behavior, and resistance to Varroa destructor mites. All sampled colonies were Africanized by maternal descent, with over 65% presence of European alleles at the S-3 nuclear locus. In two assays evaluating defense, Puerto Rican bees showed low defensiveness similar to European bees. In morphology and resistance to mites, Africanized bees from Puerto Rico are similar to other Africanized bees. In behavioral assays on mechanisms of resistance to Varroa, we directly observed that Puerto Rican Africanized bees groomed-off and bit the mites as been observed in other studies. In no other location, Africanized bees have reduced defensiveness while retaining typical traits such as wing size and mite resistance. This mosaic of traits that has resulted during the invasion of an oceanic island has implications for behavior, evolution, and agriculture. PMID:23144660

  10. A Survey of Techniques for Approximate Computing

    DOE PAGESBeta

    Mittal, Sparsh

    2016-03-18

    Approximate computing trades off computation quality with the effort expended and as rising performance demands confront with plateauing resource budgets, approximate computing has become, not merely attractive, but even imperative. Here, we present a survey of techniques for approximate computing (AC). We discuss strategies for finding approximable program portions and monitoring output quality, techniques for using AC in different processing units (e.g., CPU, GPU and FPGA), processor components, memory technologies etc., and programming frameworks for AC. Moreover, we classify these techniques based on several key characteristics to emphasize their similarities and differences. Finally, the aim of this paper is tomore » provide insights to researchers into working of AC techniques and inspire more efforts in this area to make AC the mainstream computing approach in future systems.« less

  11. Adiabatic approximation for the density matrix

    NASA Astrophysics Data System (ADS)

    Band, Yehuda B.

    1992-05-01

    An adiabatic approximation for the Liouville density-matrix equation which includes decay terms is developed. The adiabatic approximation employs the eigenvectors of the non-normal Liouville operator. The approximation is valid when there exists a complete set of eigenvectors of the non-normal Liouville operator (i.e., the eigenvectors span the density-matrix space), the time rate of change of the Liouville operator is small, and an auxiliary matrix is nonsingular. Numerical examples are presented involving efficient population transfer in a molecule by stimulated Raman scattering, with the intermediate level of the molecule decaying on a time scale that is fast compared with the pulse durations of the pump and Stokes fields. The adiabatic density-matrix approximation can be simply used to determine the density matrix for atomic or molecular systems interacting with cw electromagnetic fields when spontaneous emission or other decay mechanisms prevail.

  12. Approximate probability distributions of the master equation

    NASA Astrophysics Data System (ADS)

    Thomas, Philipp; Grima, Ramon

    2015-07-01

    Master equations are common descriptions of mesoscopic systems. Analytical solutions to these equations can rarely be obtained. We here derive an analytical approximation of the time-dependent probability distribution of the master equation using orthogonal polynomials. The solution is given in two alternative formulations: a series with continuous and a series with discrete support, both of which can be systematically truncated. While both approximations satisfy the system size expansion of the master equation, the continuous distribution approximations become increasingly negative and tend to oscillations with increasing truncation order. In contrast, the discrete approximations rapidly converge to the underlying non-Gaussian distributions. The theory is shown to lead to particularly simple analytical expressions for the probability distributions of molecule numbers in metabolic reactions and gene expression systems.

  13. An approximation method for electrostatic Vlasov turbulence

    NASA Technical Reports Server (NTRS)

    Klimas, A. J.

    1979-01-01

    Electrostatic Vlasov turbulence in a bounded spatial region is considered. An iterative approximation method with a proof of convergence is constructed. The method is non-linear and applicable to strong turbulence.

  14. Linear Approximation SAR Azimuth Processing Study

    NASA Technical Reports Server (NTRS)

    Lindquist, R. B.; Masnaghetti, R. K.; Belland, E.; Hance, H. V.; Weis, W. G.

    1979-01-01

    A segmented linear approximation of the quadratic phase function that is used to focus the synthetic antenna of a SAR was studied. Ideal focusing, using a quadratic varying phase focusing function during the time radar target histories are gathered, requires a large number of complex multiplications. These can be largely eliminated by using linear approximation techniques. The result is a reduced processor size and chip count relative to ideally focussed processing and a correspondingly increased feasibility for spaceworthy implementation. A preliminary design and sizing for a spaceworthy linear approximation SAR azimuth processor meeting requirements similar to those of the SEASAT-A SAR was developed. The study resulted in a design with approximately 1500 IC's, 1.2 cubic feet of volume, and 350 watts of power for a single look, 4000 range cell azimuth processor with 25 meters resolution.

  15. Approximation concepts for efficient structural synthesis

    NASA Technical Reports Server (NTRS)

    Schmit, L. A., Jr.; Miura, H.

    1976-01-01

    It is shown that efficient structural synthesis capabilities can be created by using approximation concepts to mesh finite element structural analysis methods with nonlinear mathematical programming techniques. The history of the application of mathematical programming techniques to structural design optimization problems is reviewed. Several rather general approximation concepts are described along with the technical foundations of the ACCESS 1 computer program, which implements several approximation concepts. A substantial collection of structural design problems involving truss and idealized wing structures is presented. It is concluded that since the basic ideas employed in creating the ACCESS 1 program are rather general, its successful development supports the contention that the introduction of approximation concepts will lead to the emergence of a new generation of practical and efficient, large scale, structural synthesis capabilities in which finite element analysis methods and mathematical programming algorithms will play a central role.

  16. Rural African American Parents’ Knowledge and Decisions About Human Papillomavirus Vaccination

    PubMed Central

    Thomas, Tami Lynn; Strickland, Ora L.; DiClemente, Ralph; Higgins, Melinda; Haber, Michael

    2014-01-01

    Purpose To identify predictors of human papillomavirus (HPV) vaccination among rural African American families. Design Cross-sectional descriptive study in schools in three rural counties in southeastern United States. The sample consisted of African American parents or caregivers with children 9 to 13 years of age who attended elementary or middle school in 2010–2011. Methods Using an anonymous, 26-item survey, we collected descriptive data during parent-teacher events from African American parents with children in elementary or middle school. The main outcome was measured as a response of “yes” to the statement “I have or will vaccinate my child with the HPV vaccine.” In addition, composite scores of knowledge and positive attitudes and beliefs were compared. No interventions were conducted. Findings We identified predictors of HPV vaccination and found that religious affiliation had a correlation with vaccinating or planning to vaccinate a child. Conclusions Results indicate a need for further research on the role of local culture, including religion and faith, in rural African Americans’ decisions about giving their children the HPV vaccination. Clinical Relevance This study emphasizes the importance of understanding rural African American parents’ knowledge, attitudes, and spiritual beliefs when designing health education programs and public health interventions to increase HPV vaccination uptake among African American boys and girls living in rural areas. PMID:23126428

  17. Evolutionary and comparative anatomical investigations of the autonomic cardiac nervous system in the African Cercopithecidae.

    PubMed

    Kawashima, Tomokazu; Akita, Keiichi; Sato, Kenji; Sasaki, Hiroshi

    2007-09-01

    The purpose of this study was to clarify the general architecture and morphological variations of the autonomic cardiac nervous system (ACNS) in the African Cercopithecidae (Old World monkeys), and to discuss the evolutionary changes between this system in African/Asian Cercopithecidae and humans. A detailed macroscopic comparative morphological investigation of the ACNS was performed by examining the left and right sides of 11 African cercopithecid specimens, including some previously unreported species (Abyssinian colobus, Angola pied colobus, Savanna monkey, and lesser white-nosed guenon). The common characteristics of the ACNS in the African Cercopithecidae are described in detail. Consequently, homologies of the ACNS between Asian (macaques) and African Cercopithecidae, and differences between the Asian/African Cercopithecidae and humans, were found. In particular, differences in the sympathetic (cardiac) systems of the Cercopithecidae and humans were recognized, despite the similar morphology of the parasympathetic vagal (cardiac) system. These differences include the composition of the cervicothoracic ganglion, the lower positions of the middle cervical and cervicothoracic ganglia, and the narrow range for the origin of the cardiac nerves in the Cercopithecidae, compared with that in humans. In conclusion, these findings are considered with regard to the morphology of the last common ancestors of the Cercopithecidae. PMID:17591730

  18. Serological survey for two simian retroviruses in macaques and African green monkeys.

    PubMed

    Krugner-Higby, L; Kucera, L; Lerche, N; Sever, J; Fucillo, W; Allan, J; Benveniste, R

    1990-01-01

    Colonies of nonhuman primates at the Bowman Gray School of Medicine (BGSM) were tested for antibodies to two retroviruses associated with immunodeficiency by indirect immunofluorescence (IFA) and western blot. A total of 471 cynomolgus macaques (Macaca fascicularis), 144 rhesus monkeys (M. mulatta) and 67 stumptail monkey M. arctoides) were tested for SRV-1, and 152 African green monkeys (Cercopithecus aethiops) were tested for SIV. Of the macaques tested, 170 (36%) cynomolgus, 5 (3%) rhesus and 8 (12%) stumptails were positive for SRV-1 antibodies by IFA. Of the African green monkeys, 54 (36%) were IFA positive for SIV antibodies. A total of 143 African green monkeys tested by IFA also were tested by western blot. In the African green monkeys, the IFA had a positive predictive value of 98% and a negative predictive value of 96%. Of 176 IFA positive macaque sera tested by western blot, 49 (28%) were positive, 55 (31%) were considered equivocal (only one band, usually to p27 core protein), and 72 (41%) were negative. PMID:2153854

  19. Some Recent Progress for Approximation Algorithms

    NASA Astrophysics Data System (ADS)

    Kawarabayashi, Ken-ichi

    We survey some recent progress on approximation algorithms. Our main focus is the following two problems that have some recent breakthroughs; the edge-disjoint paths problem and the graph coloring problem. These breakthroughs involve the following three ingredients that are quite central in approximation algorithms: (1) Combinatorial (graph theoretical) approach, (2) LP based approach and (3) Semi-definite programming approach. We also sketch how they are used to obtain recent development.

  20. Polynomial approximation of functions in Sobolev spaces

    NASA Technical Reports Server (NTRS)

    Dupont, T.; Scott, R.

    1980-01-01

    Constructive proofs and several generalizations of approximation results of J. H. Bramble and S. R. Hilbert are presented. Using an averaged Taylor series, we represent a function as a polynomial plus a remainder. The remainder can be manipulated in many ways to give different types of bounds. Approximation of functions in fractional order Sobolev spaces is treated as well as the usual integer order spaces and several nonstandard Sobolev-like spaces.

  1. Approximate Solutions Of Equations Of Steady Diffusion

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1992-01-01

    Rigorous analysis yields reliable criteria for "best-fit" functions. Improved "curve-fitting" method yields approximate solutions to differential equations of steady-state diffusion. Method applies to problems in which rates of diffusion depend linearly or nonlinearly on concentrations of diffusants, approximate solutions analytic or numerical, and boundary conditions of Dirichlet type, of Neumann type, or mixture of both types. Applied to equations for diffusion of charge carriers in semiconductors in which mobilities and lifetimes of charge carriers depend on concentrations.

  2. Polynomial approximation of functions in Sobolev spaces

    SciTech Connect

    Dupont, T.; Scott, R.

    1980-04-01

    Constructive proofs and several generalizations of approximation results of J. H. Bramble and S. R. Hilbert are presented. Using an averaged Taylor series, we represent a function as a polynomical plus a remainder. The remainder can be manipulated in many ways to give different types of bounds. Approximation of functions in fractional order Sobolev spaces is treated as well as the usual integer order spaces and several nonstandard Sobolev-like spaces.

  3. Striving to be in the profession and of It: the African American experience in physical education and kinesiology.

    PubMed

    Wiggins, David K; Wiggins, Brenda P

    2011-06-01

    This study analyzes the experiences of African Americans in the physical education and kinesiology profession since the late 1850s. Using a variety of primary and secondary source material, we place special emphasis on the experiences of African American physical educators in higher education and in the American Alliance for Health, Physical Education, Recreation and Dance and its southern, regional, and state chapters. Apparent from this examination is that African Americans have experienced various forms of racially discriminatory practices in physical education and kinesiology and have found it extraordinarily difficult to assume leader ship positions in the profession and be acknowledged for their scholarly and academic accomplishments. PMID:21699112

  4. Reading ability and computer-related attitudes among African American graduate students.

    PubMed

    Collins, Kathleen M T; Onwuegbuzie, Anthony J; Jiao, Qun G

    2008-06-01

    This study examined the degree that African American graduate students' reading abilities predict their attitudes toward computers and the educational use of the Internet. A canonical correlation analysis revealed that students with the lowest levels of reading ability tended to report the least computer confidence, least positive attitudes regarding computer liking, and least positive attitudes toward the educational use of the Internet. Findings of the study provide support for the hypothesis that reading ability differentially impacts African American graduate students' computer-related attitudes. The findings also suggest that reading ability may impede African American students' acquisition of computer and Internet skills and may negatively impact their achievement levels in graduate courses requiring computer-based skills. PMID:18537506

  5. The African diaspora: mitochondrial DNA and the Atlantic slave trade.

    PubMed

    Salas, Antonio; Richards, Martin; Lareu, María-Victoria; Scozzari, Rosaria; Coppa, Alfredo; Torroni, Antonio; Macaulay, Vincent; Carracedo, Angel

    2004-03-01

    Between the 15th and 19th centuries ad, the Atlantic slave trade resulted in the forced movement of approximately 13 million people from Africa, mainly to the Americas. Only approximately 11 million survived the passage, and many more died in the early years of captivity. We have studied 481 mitochondrial DNAs (mtDNAs) of recent African ancestry in the Americas and in Eurasia, in an attempt to trace them back to particular regions of Africa. Our results show that mtDNAs in America and Eurasia can, in many cases, be traced to broad geographical regions within Africa, largely in accordance with historical evidence, and raise the possibility that a greater resolution may be possible in the future. However, they also indicate that, at least for the moment, considerable caution is warranted when assessing claims to be able to trace the ancestry of particular lineages to a particular locality within modern-day Africa. PMID:14872407

  6. An improved proximity force approximation for electrostatics

    SciTech Connect

    Fosco, Cesar D.; Lombardo, Fernando C.; Mazzitelli, Francisco D.

    2012-08-15

    A quite straightforward approximation for the electrostatic interaction between two perfectly conducting surfaces suggests itself when the distance between them is much smaller than the characteristic lengths associated with their shapes. Indeed, in the so called 'proximity force approximation' the electrostatic force is evaluated by first dividing each surface into a set of small flat patches, and then adding up the forces due two opposite pairs, the contributions of which are approximated as due to pairs of parallel planes. This approximation has been widely and successfully applied in different contexts, ranging from nuclear physics to Casimir effect calculations. We present here an improvement on this approximation, based on a derivative expansion for the electrostatic energy contained between the surfaces. The results obtained could be useful for discussing the geometric dependence of the electrostatic force, and also as a convenient benchmark for numerical analyses of the tip-sample electrostatic interaction in atomic force microscopes. - Highlights: Black-Right-Pointing-Pointer The proximity force approximation (PFA) has been widely used in different areas. Black-Right-Pointing-Pointer The PFA can be improved using a derivative expansion in the shape of the surfaces. Black-Right-Pointing-Pointer We use the improved PFA to compute electrostatic forces between conductors. Black-Right-Pointing-Pointer The results can be used as an analytic benchmark for numerical calculations in AFM. Black-Right-Pointing-Pointer Insight is provided for people who use the PFA to compute nuclear and Casimir forces.

  7. Condom use among South African adolescents: developing and testing theoretical models of intentions and behavior.

    PubMed

    Bryan, Angela; Kagee, Ashraf; Broaddus, Michelle R

    2006-07-01

    We developed and tested models of intentions and behavior among adolescents from Cape Town, South Africa. Data from 261 participants who completed an initial measure of attitudes, beliefs, and prior behavior were used to develop a model of intentions to use condoms based on the Theory of Planned Behavior (TPB) and additional constructs found to be important in previous research with adolescents. Of the initial sample, 227 (87%) completed a behavioral follow-up 4 months later, and approximately one-third of those (n=72; 44 boys and 30 girls) reported having had sex in the prior 4 months. Data from this smaller sample were used to develop a model of condom use behavior based on intentions (as per the TPB) and the additional sub-population relevant constructs. Analyses generally supported the validity of the TPB in this context for predicting intentions and behavior. HIV knowledge and positive outlook (self-esteem and future optimism) were significantly related to TPB predictors of intentions. Intentions, acceptance of sexuality, and gender were significant predictors of behavior. Implications for the status of the TPB and the design of interventions for South African adolescents are discussed. PMID:16636891

  8. Comment on the Central Drug Authority's position statement on cannabis.

    PubMed

    Scott, Keith

    2016-01-01

    The Central Drug Authority's 'Position statement on cannabis' in this issue of SAMJ is a welcome, if somewhat belated, article that gives an indication of the South African government's response to the shifting sands of local and international public opinion and global drug policies. This editorial comments on the statement. PMID:27245714

  9. Creating Positive Culture in a New Urban High School

    ERIC Educational Resources Information Center

    Rhodes, Virginia; Stevens, Douglas; Hemmings, Annette

    2011-01-01

    In August 2009, a new urban public high school featuring project-based science, technology, engineering, and mathematics (STEM) education opened with a population of African-American, low-income, and special needs students. A planning team comprised of lead teachers and the school principal sought to create a positive school culture with a clear…

  10. Experiences of African American Young Women in Science, Technology, Engineering, and Mathematics (STEM) Education

    NASA Astrophysics Data System (ADS)

    Kolo, Yovonda Ingram

    African American women are underrepresented in science, technology, engineering, and mathematics (STEM) fields throughout the United States. As the need for STEM professionals in the United States increases, it is important to ensure that African American women are among those professionals making valuable contributions to society. The purpose of this phenomenological study was to describe the experiences of African American young women in relation to STEM education. The research question for this study examined how experiences with STEM in K-10 education influenced African American young women's academic choices in their final years in high school. The theory of multicontextuality was used to provide the conceptual framework. The primary data source was interviews. The sample was composed of 11 African American young women in their junior or senior year in high school. Data were analyzed through the process of open coding, categorizing, and identifying emerging themes. Ten themes emerged from the answers to research questions. The themes were (a) high teacher expectations, (b) participation in extra-curricular activities, (c) engagement in group-work, (d) learning from lectures, (e) strong parental involvement, (f) helping others, (g) self-efficacy, (h) gender empowerment, (i) race empowerment, and (j) strategic recruitment practices. This study may lead to positive social change by adding to the understanding of the experiences of African American young women in STEM. By doing so, these findings might motivate other African American young women to pursue advanced STEM classes. These findings may also provide guidance to parents and educators to help increase the number of African American women in STEM.

  11. Genetic diversity, introgression and relationships among West/Central African cattle breeds

    PubMed Central

    Ibeagha-Awemu, Eveline Mengwi; Jann, Oliver Carl; Weimann, Christina; Erhardt, Georg

    2004-01-01

    Genetic diversity, introgression and relationships were studied in 521 individuals from 9 African Bos indicus and 3 Bos taurus cattle breeds in Cameroon and Nigeria using genotype information on 28 markers (16 microsatellite, 7 milk protein and 5 blood protein markers). The genotypes of 13 of the 16 microsatellite markers studied on three European (German Angus, German Simmental and German Yellow) and two Indian (Nelore and Ongole) breeds were used to assess the relationships between them and the African breeds. Diversity levels at microsatellite loci were higher in the zebu than in the taurine breeds and were generally similar for protein loci in the breeds in each group. Microsatellite allelic distribution displayed groups of alleles specific to the Indian zebu, African taurine and European taurine. The level of the Indian zebu genetic admixture proportions in the African zebus was higher than the African taurine and European taurine admixture proportions, and ranged from 58.1% to 74.0%. The African taurine breed, Muturu was free of Indian zebu genes while its counter Namchi was highly introgressed (30.2%). Phylogenic reconstruction and principal component analysis indicate close relationships among the zebu breeds in Cameroon and Nigeria and a large genetic divergence between the main cattle groups – African taurine, European taurine and Indian zebu, and a central position for the African zebus. The study presents the first comprehensive information on the hybrid composition of the individual cattle breeds of Cameroon and Nigeria and the genetic relationships existing among them and other breeds outside of Africa. Strong evidence supporting separate domestication events for the Bos species is also provided. PMID:15496287

  12. Continental monophyly of cichlid fishes and the phylogenetic position of Heterochromis multidens.

    PubMed

    Keck, Benjamin P; Hulsey, C Darrin

    2014-04-01

    The incredibly species-rich cichlid fish faunas of both the Neotropics and Africa are generally thought to be reciprocally monophyletic. However, the phylogenetic affinity of the African cichlid Heterochromis multidens is ambiguous, and this distinct lineage could make African cichlids paraphyletic. In past studies, Heterochromis has been variously suggested to be one of the earliest diverging lineages within either the Neotropical or the African cichlid radiations, and it has even been hypothesized to be the sister lineage to a clade containing all Neotropical and African cichlids. We examined the phylogenetic relationships among a representative sample of cichlids with a dataset of 29 nuclear loci to assess the support for the different hypotheses of the phylogenetic position of Heterochromis. Although individual gene trees in some instances supported alternative relationships, a majority of gene trees, integration of genes into species trees, and hypothesis testing of putative topologies all supported Heterochromis as belonging to the clade of African cichlids. PMID:24472673

  13. Genomic Ancestry of North Africans Supports Back-to-Africa Migrations

    PubMed Central

    Gravel, Simon; Wang, Wei; Brisbin, Abra; Byrnes, Jake K.; Fadhlaoui-Zid, Karima; Zalloua, Pierre A.; Moreno-Estrada, Andres; Bertranpetit, Jaume; Bustamante, Carlos D.; Comas, David

    2012-01-01

    North African populations are distinct from sub-Saharan Africans based on cultural, linguistic, and phenotypic attributes; however, the time and the extent of genetic divergence between populations north and south of the Sahara remain poorly understood. Here, we interrogate the multilayered history of North Africa by characterizing the effect of hypothesized migrations from the Near East, Europe, and sub-Saharan Africa on current genetic diversity. We present dense, genome-wide SNP genotyping array data (730,000 sites) from seven North African populations, spanning from Egypt to Morocco, and one Spanish population. We identify a gradient of likely autochthonous Maghrebi ancestry that increases from east to west across northern Africa; this ancestry is likely derived from “back-to-Africa” gene flow more than 12,000 years ago (ya), prior to the Holocene. The indigenous North African ancestry is more frequent in populations with historical Berber ethnicity. In most North African populations we also see substantial shared ancestry with the Near East, and to a lesser extent sub-Saharan Africa and Europe. To estimate the time of migration from sub-Saharan populations into North Africa, we implement a maximum likelihood dating method based on the distribution of migrant tracts. In order to first identify migrant tracts, we assign local ancestry to haplotypes using a novel, principal component-based analysis of three ancestral populations. We estimate that a migration of western African origin into Morocco began about 40 generations ago (approximately 1,200 ya); a migration of individuals with Nilotic ancestry into Egypt occurred about 25 generations ago (approximately 750 ya). Our genomic data reveal an extraordinarily complex history of migrations, involving at least five ancestral populations, into North Africa. PMID:22253600

  14. Teachers' Perception of African American Middle School Girls' Interest in Mathematics and Science

    NASA Astrophysics Data System (ADS)

    Best, Bonnie M.

    Research into African American female underrepresentation in science, technology, engineering, and mathematics (STEM) fields has become an area of interest due to the fact that a majority of African American middle school females do not possess the high levels of mathematics and science knowledge because of social and cultural barriers both inside and outside school that challenge their academic success. The purpose of this qualitative interpretative phenomenological study was to explore teachers' shared, lived experiences of teaching mathematics and science to African American middle school girls. Delgado and Stefancic's critical race theory, Pratt-Clarke's critical race feminism, and Baker-Miller's relational-cultural theory were used to guide this study. Research questions focused on the perceptions and experiences of teachers' lived experiences teaching mathematics and science to African American middle school females. Criterion, purposive, and maximum variation sampling techniques were used to recruit 10 teachers who have 3 or more years' experience teaching African American middle school girls. Semistructured face-to-face interviews were the primary data collection source. First cycle and second cycle coding methods were used to support the analysis of this study. Findings suggest that there is a connection between a positive student-teacher relationship and academic success. The results of this study contribute to positive social change by providing empirical evidence policymakers and teachers can use to improve the mathematics and science instruction and practices that are needed to meet the needs of African American middle school females and reduce the underrepresentation and underachievement of African American females in mathematics and science.

  15. Predictors of Breastfeeding Attitudes Among College-Educated African Americans.

    PubMed

    Jefferson, Urmeka T

    2015-01-01

    Breastfeeding initiation among African American women has reached 60%; however, it is the lowest rate among all races. This racial disparity is a public health concern considering the impact of breastfeeding on infant morbidity and mortality. The purpose of this study was to explore breastfeeding exposure and determinants of breastfeeding attitudes among African Americans. The theory of planned behavior guided this study focusing on the impact of background factors on determinants of breastfeeding attitudes. This secondary analysis included 348 African American college students with a mean age of 22 years with no children. The Iowa Infant Feeding Attitude Scale and a demographic questionnaire were used to collect data. A significant association between knowing someone who breastfed her infant and being breastfed as an infant (p < .001) was observed. Although gender, education, and breastfeeding exposure explained 15% of the variance in breastfeeding attitudes, being breastfed as an infant had no significant (p = .611) contribution. Breastfeeding exposure to someone who has breastfed her infant is a modifiable factor that influenced positive breastfeeding attitudes. Therefore, it is essential to identify strategies in practice to increase breastfeeding exposure for vulnerable populations in efforts to improve breastfeeding attitudes, intentions, and initiation. PMID:26502555

  16. Pregnant African American women's attitudes toward perinatal depression prevention.

    PubMed

    Goodman, Sherryl H; Dimidjian, Sona; Williams, Kristen G

    2013-01-01

    Depression during the perinatal period is common, debilitating, and consequential for women and their children, particularly among low income African American women. Viable approaches to prevention of depression have emerged. Yet little is known about women's preferences for approaches to preventing depression. A sample of 60 pregnant, low-income African American women seeking routine prenatal care was presented with standardized descriptions of three approaches to depression prevention (pharmacotherapy and two psychosocial approaches) and measures of preferences, perceived credibility, and personal reactions to each approach. Women also completed measures of perceived barriers and facilitators and current depression. Consistent with expectations, both of the psychosocial approaches were rated as more strongly preferred, more credible, and associated with more positive personal reactions relative to the pharmacotherapy approach. Depression did not alter women's preferences among the approaches. Contrary to prediction, women with clinically significant levels of depression did not find the pharmacotherapy approach to be more credible or to have more favorable personal reactions to it than women with low depression symptom levels. Exploration of women's perceptions of barriers revealed the importance of logistics, beliefs, and stigma barriers whereas women reported that concern about depression being impairing and ease of pragmatics would both facilitate engagement with preventive interventions. The findings suggest the need to examine the role of preferences in tests of the effectiveness of approaches to the prevention of perinatal depression in order to enhance service delivery among low income African American women. PMID:23356356

  17. Disparities in Uterine Cancer Epidemiology, Treatment, and Survival Among African Americans in the United States

    PubMed Central

    Long, B; Liu, FW; Bristow, RE

    2013-01-01

    Objective The objective of this article is to comprehensively review the scientific literature and summarize the available data regarding the outcome disparities of African American women with uterine cancer. Methods Literature on disparities in uterine cancer was systematically reviewed using the PubMed search engine. Articles from 1992-2012 written in English were reviewed. Search terms included endometrial cancer, uterine cancer, racial disparities, and African American. Results Twenty-four original research articles with a total of 366,299 cases of endometrial cancer (337,597 Caucasian and 28,702 African American) were included. Compared to Caucasian women, African American women comprise 7% of new endometrial cancer cases, while accounting for approximately 14% of endometrial cancer deaths. They are diagnosed with later stage, higher-grade disease, and poorer prognostic histologic types compared to their Caucasian counterparts. They also suffer worse outcomes at every stage, grade, and for every histologic type. The cause of increased mortality is multifactorial. African American and white women have varying incidence of comorbid conditions, genetic susceptibility to malignancy, access to care and health coverage, and socioeconomic status; however, the most consistent contributors to incidence and mortality disparities are histology and socioeconomics. More robust genetic and molecular profile studies are in development to further explain histologic differences. Conclusions Current studies suggest that histologic and socioeconomic factors explain much of the disparity in endometrial cancer incidence and mortality between white and African American patients. Treatment factors likely contributed historically to differences in mortality; however, studies suggest most women now receive equal care. Molecular differences may be an important factor to explain the racial inequities. Coupled with a sustained commitment to increasing access to appropriate care, on

  18. Generalized local-density approximation for spherical potentials

    SciTech Connect

    Zhang, X.; Nicholson, D.M.

    1999-08-01

    An alternative density functional for the spherical approximation of cell potentials is formulated. It relies on overlapping atomic spheres for the calculation of the kinetic energy, similar to the atomic sphere approximation (ASA), however, a shape correction is used that has the same form as the interstitial treatment in the nonoverlapping muffin-tin (MT) approach. The intersite Coulomb energy is evaluated using the Madelung energy as computed in the MT approach, while the on-site Coulomb energy is calculated using the ASA. The Kohn-Sham equations for the functional are then solved self-consistently. The ASA is known to give poor elastic constants and good point defect energies. Conversely the MT approach gives good elastic constants and poor point defect energies. The proposed new functional maintains the simplicity of the spherical potentials found in the ASA and MT approaches, but gives good values for both elastic constants and point defects. This solution avoids a problem, absent in the ASA but suffered by the MT approximation, of incorrect distribution of site charges when charge transfer is large. Relaxation of atomic positions is thus facilitated. Calculations confirm that the approach gives similar elastic constants to the MT approximation, and defect formation energies similar to those obtained with ASA. {copyright} {ital 1999} {ital The American Physical Society}

  19. Parallel SVD updating using approximate rotations

    NASA Astrophysics Data System (ADS)

    Goetze, Juergen; Rieder, Peter; Nossek, J. A.

    1995-06-01

    In this paper a parallel implementation of the SVD-updating algorithm using approximate rotations is presented. In its original form the SVD-updating algorithm had numerical problems if no reorthogonalization steps were applied. Representing the orthogonalmatrix V (right singular vectors) using its parameterization in terms of the rotation angles of n(n - 1)/2 plane rotations these reorthogonalization steps can be avoided during the SVD-updating algorithm. This results in a SVD-updating algorithm where all computations (matrix vector multiplication, QRD-updating, Kogbetliantz's algorithm) are entirely based on the evaluation and application of orthogonal plane rotations. Therefore, in this form the SVD-updating algorithm is amenable to an implementation using CORDIC-based approximate rotations. Using CORDIC-based approximate rotations the n(n - 1)/2 rotations representing V (as well as all other rotations) are only computed to a certain approximation accuracy (in the basis arctan 2i). All necessary computations required during the SVD-updating algorithm (exclusively rotations) are executed with the same accuracy, i.e., only r << w (w: wordlength) elementary orthonormal (mu) rotations are used per plane rotation. Simulations show the efficiency of the implementation using CORDIC-based approximate rotations.

  20. 'LTE-diffusion approximation' for arc calculations

    NASA Astrophysics Data System (ADS)

    Lowke, J. J.; Tanaka, M.

    2006-08-01

    This paper proposes the use of the 'LTE-diffusion approximation' for predicting the properties of electric arcs. Under this approximation, local thermodynamic equilibrium (LTE) is assumed, with a particular mesh size near the electrodes chosen to be equal to the 'diffusion length', based on De/W, where De is the electron diffusion coefficient and W is the electron drift velocity. This approximation overcomes the problem that the equilibrium electrical conductivity in the arc near the electrodes is almost zero, which makes accurate calculations using LTE impossible in the limit of small mesh size, as then voltages would tend towards infinity. Use of the LTE-diffusion approximation for a 200 A arc with a thermionic cathode gives predictions of total arc voltage, electrode temperatures, arc temperatures and radial profiles of heat flux density and current density at the anode that are in approximate agreement with more accurate calculations which include an account of the diffusion of electric charges to the electrodes, and also with experimental results. Calculations, which include diffusion of charges, agree with experimental results of current and heat flux density as a function of radius if the Milne boundary condition is used at the anode surface rather than imposing zero charge density at the anode.