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Sample records for african approximate position

  1. Sensing Position With Approximately Constant Contact Force

    NASA Technical Reports Server (NTRS)

    Sturdevant, Jay

    1996-01-01

    Computer-controlled electromechanical system uses number of linear variable-differential transformers (LVDTs) to measure axial positions of selected points on surface of lens, mirror, or other precise optical component with high finish. Pressures applied to pneumatically driven LVDTs adjusted to maintain small, approximately constant contact forces as positions of LVDT tips vary.

  2. Completely Positive Approximate Solutions of Driven Open Quantum Systems

    NASA Astrophysics Data System (ADS)

    Haddadfarshi, Farhang; Cui, Jian; Mintert, Florian

    2015-04-01

    We define a perturbative approximation for the solution of Lindblad master equations with time-dependent generators that satisfies the fundamental property of complete positivity, as essential for quantum simulations and optimal control. With explicit examples we show that ensuring this property substantially improves the accuracy of the perturbative approximation.

  3. Positive Parenting among African American Mothers with a Serious Illness.

    ERIC Educational Resources Information Center

    Oyserman, Daphna; Bybee, Deborah; Mowbray, Carol T.; MacFarlane, Peter

    2002-01-01

    Using a sample of African American mothers (N=202) diagnosed with mental illness, the effects of poverty; maternal education; social support; maternal and social stress; current mental health; and psychiatric history were examined for effects on positive parenting. Strongest predictors of parenting attitudes were stress and current mental health.…

  4. 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…

  5. 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…

  6. 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.

  7. Experiences of HIV-Positive African-American and African Caribbean Childbearing Women: A Qualitative Study

    PubMed Central

    Njie-Carr, Veronica; Sharps, Phyllis; Campbell, Doris; Callwood, Gloria

    2013-01-01

    This qualitative study examined the experiences of HIV-positive African-American and African Caribbean childbearing women related to decisions about HIV testing, status disclosure, adhering to treatment, decisions about childbearing, and experiences in violent intimate relationships. Twenty-three women completed a 60-minute in-depth interview. Six themes emerged: perceived vulnerability to HIV infection; feelings about getting tested for HIV; knowledge, attitudes, and behaviors after HIV diagnosis; disclosure of HIV status; living with HIV (positivity, strength, and prayer); and, experiences with physical and sexual violence. Three women (13%) reported perinatal abuse and 10 women (n = 23, 43.4%) reported lifetime abuse. Positive experiences and resilience were gained from faith and prayer. Most important to the women were the perceived benefits of protecting the health of their baby. Findings suggest that policies supporting early identification of HIV-positive childbearing women are critical in order to provide counseling and education in forming their decisions for safety precautions in violent intimate partner relationships. PMID:23061166

  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. Reliability of ultrasound evaluation of hyoid-larynx approximation with positional change.

    PubMed

    Ahn, So Young; Cho, Kang Hee; Beom, Jaewon; Park, Dong Jun; Jee, Sungju; Nam, Jin Hee

    2015-05-01

    We evaluated the reliability of ultrasound evaluation of hyoid-larynx approximation with positional change. Twenty healthy volunteers (10 men, 10 women) participated in this study. The distance between the hyoid bone and thyroid cartilage was measured by ultrasound in both the sitting and supine positions. Hyoid-larynx approximation was defined as the shortest distance between the lower tip of the hyoid bone and the upper end of the thyroid cartilage during swallowing. The transducer was placed in a longitudinal position above the midline of the larynx, which allowed visualization of the hyoid bone and thyroid cartilage. Patients were given 5 mL of water and swallowed. The measurement was repeated three times to enable averaging in each position. Using the mean distance at rest and the shortest distance during swallowing, we calculated relative laryngeal elevation. There was no significant difference in resting distance between the hyoid bone and thyroid cartilage with positional change or gender, with identical relative laryngeal elevation. However, there was a negative correlation between the resting and approximation distance and body mass index. In conclusion, ultrasound evaluation in healthy volunteers revealed no difference in hyoid-laryngeal approximation on swallowing in either the supine or sitting position. This finding is likely to be of value in the investigation of dysphagia.

  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. Approximation-Based Discrete-Time Adaptive Position Tracking Control for Interior Permanent Magnet Synchronous Motors.

    PubMed

    Yu, Jinpeng; Shi, Peng; Yu, Haisheng; Chen, Bing; Lin, Chong

    2015-07-01

    This paper considers the problem of discrete-time adaptive position tracking control for a interior permanent magnet synchronous motor (IPMSM) based on fuzzy-approximation. Fuzzy logic systems are used to approximate the nonlinearities of the discrete-time IPMSM drive system which is derived by direct discretization using Euler method, and a discrete-time fuzzy position tracking controller is designed via backstepping approach. In contrast to existing results, the advantage of the scheme is that the number of the adjustable parameters is reduced to two only and the problem of coupling nonlinearity can be overcome. It is shown that the proposed discrete-time fuzzy controller can guarantee the tracking error converges to a small neighborhood of the origin and all the signals are bounded. Simulation results illustrate the effectiveness and the potentials of the theoretic results obtained.

  15. 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…

  16. Exploring How School Counselors Position Low-Income African American Girls as Mathematics and Science Learners

    ERIC Educational Resources Information Center

    West-Olatunji, Cirecie; Shure, Lauren; Pringle, Rose; Adams, Thomasenia; Lewis, Dadria; Cholewa, Blaire

    2010-01-01

    The underrepresentation of low-income African American girls in science-related careers is of concern. Applying the concept of positionality, the authors explored how three school counselors at low-resourced schools view this population of learners to either support or discourage mathematics and science careers. The results of this study suggest…

  17. African American Community Education Partnership Summit: Focusing on Reading & Mathematics Achievement. Position Paper.

    ERIC Educational Resources Information Center

    Green, Robert L.

    This document was produced as a position paper for background for a summit convened by the San Francisco Unified School District (California) to focus on the education and achievement of African American students. The Education Partnership Summit had the principal goal of developing strategies and techniques to increase the mathematics and reading…

  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. Stochastic Perturbations and Invariant Measures of Position Dependent Random Maps via Fourier Approximations

    NASA Astrophysics Data System (ADS)

    Islam, Md Shafiqul

    Let T = {τ1(x), τ2(x),…, τK(x); p1(x), p2(x),…, pK(x)} be a position dependent random map which possesses a unique absolutely continuous invariant measure \\hat{μ} with probability density function \\hat{f}. We consider a family {TN}N≥1 of stochastic perturbations TN of the random map T. Each TN is a Markov process with the transition density ∑ {k = 1}K pk(x) qN(τ k(x), \\cdot), where qN(x, \\sdot) is a doubly stochastic periodic and separable kernel. Using Fourier approximation, we construct a finite dimensional approximation PN to a perturbed Perron-Frobenius operator. Let fN* be a fixed point of PN. We show that {fN*} converges in L1 to \\hat{f}.

  1. Stress processes in HIV-positive African American mothers: moderating effects of drug abuse history.

    PubMed

    Burns, Myron J; Feaster, Daniel J; Mitrani, Victoria B; Ow, Christina; Szapocznik, José

    2008-01-01

    This study examined the mechanism by which stressors, dissatisfaction with family, perceived control, social support, and coping were related to psychological distress in a sample of HIV-positive African American mothers. Additional analyses explored whether women who had a history of a drug abuse or dependence diagnosis differed either on levels of the study variables or the model pathways. The results indicated that HIV-positive African American mothers who had higher levels of stressors perceived their stressors as a whole to be less controllable. Coping resources, available social support and perceived control, were positively associated with active coping and negatively associated with psychological distress. Avoidant coping was the most important predictor of psychological distress. Furthermore, the effect of avoidant coping on psychological distress was stronger for mothers with a history of drug diagnosis. The implications of these findings for targeting interventions are discussed.

  2. 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

  3. A pilot study to engage and counsel HIV-positive African American youth via telehealth technology.

    PubMed

    Saberi, Parya; Yuan, Patrick; John, Malcolm; Sheon, Nicolas; Johnson, Mallory O

    2013-09-01

    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.

  4. Positive and negative qualities of South African adolescents' parent and peer relationships.

    PubMed

    Lesch, Elmien; de Jager, Nadia

    2014-01-01

    Parent and peer relationships are important social resources for adolescents. South African research on adolescents' relationships, however, underemphasises these relationships as potential positive resources. Studies also tend to use samples from urban populations, while rural and semi-rural adolescent populations are neglected. This study focused on White and Coloured adolescents living in one South African semi-rural community and their ratings of positive and negative relationship qualities in relationships with parents and peers. Using the Network of Relationships Inventory (NRI), we found that mothers, best friends and romantic partners were relatively equal sources of social support. Mothers' high ratings for support, conflict and punishment may point to mothers bearing the primary responsibility for child care. Fathers' low support ratings raise concern as father involvement is important for adolescents' well-being. White participants overall rated their relationship higher for support and lower for negative qualities than the Coloured participants.

  5. 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

  6. Measuring positive and negative affect in the voiced sounds of African elephants (Loxodonta africana).

    PubMed

    Soltis, Joseph; Blowers, Tracy E; Savage, Anne

    2011-02-01

    As in other mammals, there is evidence that the African elephant voice reflects affect intensity, but it is less clear if positive and negative affective states are differentially reflected in the voice. An acoustic comparison was made between African elephant "rumble" vocalizations produced in negative social contexts (dominance interactions), neutral social contexts (minimal social activity), and positive social contexts (affiliative interactions) by four adult females housed at Disney's Animal Kingdom®. Rumbles produced in the negative social context exhibited higher and more variable fundamental frequencies (F(0)) and amplitudes, longer durations, increased voice roughness, and higher first formant locations (F1), compared to the neutral social context. Rumbles produced in the positive social context exhibited similar shifts in most variables (F(0 )variation, amplitude, amplitude variation, duration, and F1), but the magnitude of response was generally less than that observed in the negative context. Voice roughness and F(0) observed in the positive social context remained similar to that observed in the neutral context. These results are most consistent with the vocal expression of affect intensity, in which the negative social context elicited higher intensity levels than the positive context, but differential vocal expression of positive and negative affect cannot be ruled out.

  7. The role of faith in adoption: achieving positive adoption outcomes for African American children.

    PubMed

    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 faith on choosing to adopt, achieving positive adoption outcomes, and reducing disproportionality. From Louisiana and Texas, 113 families who adopted 226 children, 48% African American, participated in a survey measuring children's behavior and parent distress (PSI-SF Difficult Child and Parent Distress Subscales) and religiosity (Hoge Intrinsic Religiosity Index). Of the respondents, 93% of the respondents belonged to a religious congregation, 86% attended church weekly. Controlling for child's behavior, religiosity predicted lower stress in adoptive parenting; church attendance was related to improvement in parental health since adopting. Faith was rated most frequently as essential in parents' decisions to adopt. The study concludes that faith may be an asset in increasing adoptions and improving adoption outcomes resulting in increased numbers of African American children adopted.

  8. 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.

  9. Engaging, Retaining, and Advancing African Americans in Executive-Level Positions: A Descriptive and Trend Analysis of Academic Administrators in Higher and Postsecondary Education

    ERIC Educational Resources Information Center

    Jackson, Jerlando F. L.

    2004-01-01

    In spite of repeated considerations and positive action to engage, retain and advance African Americans in executive positions, there are only a few African Americans in executive level administration posts in colleges and universities. An analysis of the status of African Americans in higher and post secondary education shows that legislation…

  10. "Two souls, two thoughts," two self-schemas: double consciousness can have positive academic consequences for African Americans.

    PubMed

    Brannon, Tiffany N; Markus, Hazel Rose; Taylor, Valerie Jones

    2015-04-01

    African Americans can experience a double consciousness-the two-ness of being an American and an African American. The present research hypothesized that: (a) double consciousness can function as 2 self-schemas-an independent self-schema tied to mainstream American culture and an interdependent self-schema tied to African American culture, and (b) U.S. educational settings can leverage an interdependent self-schema associated with African American culture through inclusive multicultural practices to facilitate positive academic consequences. First, a pilot experiment and Studies 1 and 2 provided evidence that double consciousness can be conceptualized as 2 self-schemas. That is, African Americans shifted their behavior (e.g., cooperation) in schema-relevant ways from more independent when primed with mainstream American culture to more interdependent when primed with African American culture. Then, Studies 3 and 4 demonstrated that incorporating African American culture within a university setting enhanced African Americans' persistence and performance on academic-relevant tasks. Finally, using the Gates Millennium Scholars dataset (Cohort 1), Study 5 conceptually replicated Studies 3 and 4 and provided support for one process that underlies the observed positive academic consequences. Specifically, Study 5 provided evidence that engagement with African American culture (e.g., involvement with cultural events/groups) on college campuses makes an interdependent self-schema more salient that increases African American students' sense of academic fit and identification, and, in turn, enhances academic performance (self-reported grades) and persistence (advanced degree enrollment in a long-term follow-up). The discussion examines double consciousness as a basic psychological phenomenon and suggests the intra- and intergroup benefits of inclusive multicultural settings.

  11. 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/.

  12. 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

  13. 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.

  14. Socioeconomic Position Is Positively Associated With Blood Pressure Dipping Among African-American Adults: The Jackson Heart Study

    PubMed Central

    Hickson, DeMarc A; Diez Roux, Ana V; Wyatt, Sharon B; Gebreab, Samson Y; Ogedegbe, Gbenga; Sarpong, Daniel F; Taylor, Herman A; Wofford, Marion R

    2014-01-01

    BACKGROUND Blunted nocturnal blood pressure (NBP) dipping is a significant predictor of cardiovascular events. Lower socioeconomic position (SEP) may be an important predictor of NBP dipping, especially in African Americans (AA). However, the determinants of NBP dipping are not fully understood. METHODS The cross-sectional associations of individual and neighborhood SEP with NBP dipping, assessed by 24-h ambulatory BP monitoring, were examined among 837 AA adults (Mean age: 59.2 ± 10.7 years; 69.2% women), after adjustment for age, sex, hypertension status, body mass index (BMI), health behaviors, office, and 24-h systolic BP (SBP). RESULTS The mean hourly SBP was consistently lower among participants in the highest category of individual income compared to those in the lowest category, and these differences were most pronounced during sleeping hours. The odds of NBP dipping (defined as >10% decline in the mean asleep SBP compared to the mean awake SBP) increased by 31% (95% confidence interval: 13–53%) and 18% (95% confidence interval: 0–39%) for each s.d. increase in income and years of education, respectively, after multivariable adjustment. CONCLUSIONS NBP dipping is patterned by income and education in AA adults even after accounting for known risk factors. These results suggest that low SEP is a risk factor for insufficient NBP dipping in AA. PMID:21654853

  15. 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

  16. Evidence of positive selection in mitochondrial complexes I and V of the African elephant.

    PubMed

    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.

  17. 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

  18. "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…

  19. Positive selection of a gene family during the emergence of humans and African apes.

    PubMed

    Johnson, M E; Viggiano, L; Bailey, J A; Abdul-Rauf, M; Goodwin, G; Rocchi, M; Eichler, E E

    2001-10-04

    Gene duplication followed by adaptive evolution is one of the primary forces for the emergence of new gene function. Here we describe the recent proliferation, transposition and selection of a 20-kilobase (kb) duplicated segment throughout 15 Mb of the short arm of human chromosome 16. The dispersal of this segment was accompanied by considerable variation in chromosomal-map location and copy number among hominoid species. In humans, we identified a gene family (morpheus) within the duplicated segment. Comparison of putative protein-encoding exons revealed the most extreme case of positive selection among hominoids. The major episode of enhanced amino-acid replacement occurred after the separation of human and great-ape lineages from the orangutan. Positive selection continued to alter amino-acid composition after the divergence of human and chimpanzee lineages. The rapidity and bias for amino-acid-altering nucleotide changes suggest adaptive evolution of the morpheus gene family during the emergence of humans and African apes. Moreover, some genes emerge and evolve very rapidly, generating copies that bear little similarity to their ancestral precursors. Consequently, a small fraction of human genes may not possess discernible orthologues within the genomes of model organisms.

  20. African American Male Initiatives and Positive Change: Understanding the Process of Successful Program Development

    ERIC Educational Resources Information Center

    Patterson, Randall B.

    2012-01-01

    The previous decade has seen the creation of African American Male Initiative programs at colleges and universities across the United States. These programs were created in response to the low retention and graduation rates of African American males on these campuses. There has been little research, however, to discover best practices for these…

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. HIV treatment optimism and sexual risk behaviors among HIV positive African American men who have sex with men.

    PubMed

    Peterson, John L; Miner, Michael H; Brennan, David J; Rosser, B R Simon

    2012-04-01

    The association between HIV treatment optimism--beliefs about susceptibility to transmit HIV, motivation to use condoms, and severity of HIV--and sexual risk behavior was examined among HIV-positive African American men who have sex with men (MSM). Participants were 174 men recruited in four major metropolitan areas of the United States to participate in a weekend HIV risk reduction intervention. Baseline results revealed that beliefs in less susceptibility to transmit HIV and less motivation to use condoms were significantly associated with more unprotected anal intercourse among serodiscordant casual partners. Less motivation to use condoms also predicted more unprotected insertive and receptive anal sex and was more important than susceptibility beliefs in predicting these behaviors. Suggestions are offered of ways to better inform HIV-positive African American MSM about their misperceptions about HIV treatment and how their level of optimism about HIV treatment may diminish or encourage condom use.

  6. 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.

  7. Symmetric flux continuous positive definite approximation of the elliptic full tensor pressure equation in local conservative form

    SciTech Connect

    Edwards, M.G.

    1995-12-31

    A classical finite volume scheme well known in computational aerodynamics for solving the Transonic full potential equation is imported into reservoir simulation and applied to the full tensor pressure equation. Cell vertex discretization is shown to be a natural framework for approximation. With permeability placed at the cell centers and potential at the vertices (cell corner points), of the grid the scheme is flux continuous and locally conservative. Analysis is presented which proves that the resulting discrete matrix is symmetric positive definite provided the full permeability tensor is symmetric elliptic. The discrete matrix is also diagonally dominant subject to a sufficient elliptically condition. For a diagonal anisotropic tensor the discrete matrix is always symmetric positive definite and the scheme is up to 4th order accurate. A cell centered version of the scheme is indicated.

  8. 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…

  9. 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…

  10. 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…

  11. 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…

  12. 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

  13. 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.

  14. Project Exhale: preliminary evaluation of a tailored smoking cessation treatment for HIV-positive African American smokers.

    PubMed

    Matthews, Alicia K; Conrad, Megan; Kuhns, Lisa; Vargas, Maria; King, Andrea C

    2013-01-01

    This study examined the feasibility, acceptability, and outcomes of a culturally tailored smoking cessation intervention for HIV-positive African American male smokers. Eligible smokers were enrolled in a seven-session group-based treatment combined with nicotine patch. The mean age of participants was M=46 years. The majority were daily smokers (71%), smoked a mentholated brand (80%), and averaged 8.6 (standard deviation [SD]=8.1) cigarettes per day. Baseline nicotine dependency scores (M=5.8) indicated a moderate to high degree of physical dependence. Of the 31 participants enrolled, the majority completed treatment (≥3 sessions; 68%), 1-month follow-up (74%), and 3-month follow-up (87%) interviews. Program acceptability scores were strong. However, adherence to the patch was low, with 39% reporting daily patch use. The majority of participants (80%, n=24) made a quit attempt. Furthermore, over the course of the intervention, smoking urge, cigarettes smoked, nicotine dependence, withdrawal symptoms, and depression scores all significantly decreased. Follow-up quit rates at 1 and 3 months ranged from 6% to 24%, with treatment completers having better outcomes. This first of its kind intervention for HIV-positive African American male smokers was feasible, acceptable, and showed benefit for reducing smoking behaviors and depression scores. Smoking cessation outcomes were on par with other similar programs. A larger trial is needed to address limitations and to confirm benefits.

  15. The association between depressive symptoms, anger, and perceived support resources among underserved older HIV positive black/African American adults.

    PubMed

    Whitehead, Nicole Ennis; Hearn, Lauren E; Burrell, Larry

    2014-09-01

    By 2015, half of those living with HIV in the United States will be ≥50 years of age. Research suggests that perceived social support is an important factor in maintaining positive health behaviors in this population. The present study examined the relationship between depressive symptoms and trait anger on perceived social support in a sample of low-income HIV positive (HIV+) African Americans ≥50 years of age. Additionally, we examined life stressors moderated the relationship between mental health and perceived support. This study includes 95 HIV+ men and women ≥50 years of age who identify as black/African American. As expected, depressive symptoms and trait anger showed a strong inverse relationship with perceived support resources. Furthermore, life stressors also showed a strong inverse relationship with perceived support. However, life stressors did not moderate the relationship between depressive symptoms and anger. Instead life stressors demonstrated a strong independent relationship with perceived support. The association between depressive symptoms, trait anger, life stressors, and lower perceived support suggests that these factors play a role in one's ability to access needed support resources. Greater perceived support is associated with improved health in HIV+ persons, and may be especially important in tailoring interventions for those ≥50 years of age.

  16. 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.

  17. Psychometric Properties of Positive and Negative Affect Schedule (PANAS) Original and Short Forms in an African American Community Sample

    PubMed Central

    Merz, Erin L.; Malcarne, Vanessa L.; Roesch, Scott C.; Ko, Celine M.; Emerson, Marc; Roma, Vincenzo G.; Sadler, Georgia Robins

    2014-01-01

    Background The Positive and Negative Affect Schedule (PANAS) has been widely used as a self-report measure of affect in community and clinical contexts. However, evaluations of the psychometric properties of PANAS scores have been limited in diverse ethnic groups. Several short forms of the PANAS have also been proposed, but very little is known about the psychometric properties of these versions. Methods The present study investigated the psychometric properties, including the factor structure of the original PANAS and two short forms in an African American community sample (N = 239). Descriptive, internal consistency reliability, factorial validity, and measurement invariance analyses were conducted. Results All PANAS subscales from the original and short forms had adequate internal consistency. For the original PANAS, the model specifying three correlated factors (Positive Affect, Afraid, Upset) with correlated uniquenesses from redundant items provided the best fit to the data. However, the two-factor model (Positive Affect, Negative Affect) with correlated uniquenesses was also supported. For both short forms, the two-factor model with correlated uniquenesses fit the data best. Factors from all forms were generally invariant across age and gender, although there was some minor invariance at the item level. Limitations Participants were from a limited geographic area and one ethnic group. Indicators of anxiety, depression, and cultural characteristics were not measured. Conclusion The factor structure was replicated, suggesting no immediate concerns regarding the valid interpretation of PANAS scores. The results support the reliability and validity of the PANAS and its short forms for use among African Americans. PMID:24051099

  18. 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…

  19. Observed Racial Socialization and Maternal Positive Emotions in African American Mother-Adolescent Discussions About Racial Discrimination.

    PubMed

    Smith-Bynum, Mia A; Anderson, Riana E; Davis, BreAnna L; Franco, Marisa G; English, Devin

    2016-11-01

    This study examined patterns of (a) observed racial socialization messages in dyadic discussions between 111 African American mothers and adolescents (Mage  = 15.50) and (b) mothers' positive emotions displayed during the discussion. Mothers displayed more advocacy on behalf of their adolescents in response to discrimination by a White teacher than to discrimination by a White salesperson. Mothers displayed consistent emotional support of adolescents' problem solving across both dilemmas but lower warmth in response to the salesperson dilemma. Findings illustrate evidence of the transactional nature of racial socialization when presented with adolescents' racial dilemmas. The role of adolescent gender in mothers' observed racial socialization responses is also discussed. A framework for a process-oriented approach to racial socialization is presented.

  20. Teacher positioning on the teaching of sexual diversity in South African schools.

    PubMed

    Francis, Dennis A

    2012-01-01

    This paper reports on research with 11 high school teachers in Durban and draws on positioning theory to raise important questions on the teaching of issues relating to homosexuality and bisexuality within sexuality education. Using data collected from classroom observations and in-depth interviews, it demonstrates that issues related to sexual diversity were in most cases ignored or avoided by teachers and when teachers did include aspects of homosexuality, they took up positions that endorsed the idea of 'compulsory heterosexuality'. I conclude by paying attention to ways we can deepen the teaching of homosexual and bisexual issues.

  1. 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…

  2. 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…

  3. 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…

  4. 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.

  5. "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…

  6. 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…

  7. 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

  8. Perceptions Towards Condom Use, Sexual Activity, and HIV Disclosure among HIV-Positive African American Men Who Have Sex with Men: Implications for Heterosexual Transmission

    PubMed Central

    Harawa, Nina T.; Ramamurthi, Hema Codathi; Bingham, Trista A.

    2006-01-01

    Disproportionately high HIV/AIDS rates and frequent non-gay identification (NGI) among African American men who have sex with men or with both men and women (MSM/W) highlight the importance of understanding how HIV-positive African American MSM/W perceive safer sex, experience living with HIV, and decide to disclose their HIV status. Thirty predominately seropositive and non-gay identifying African American MSM/W in Los Angeles participated in three semi-structured focus group interviews, and a constant comparison method was used to analyze responses regarding condom use, sexual activity after an HIV diagnosis, and HIV serostatus disclosure. Condom use themes included its protective role against disease and pregnancy, acceptability concerns pertaining to aesthetic factors and effectiveness, and situational influences such as exchange sex, substance use, and suspicions from female partners. Themes regarding the impact of HIV on sexual activity included rejection, decreased partner seeking, and isolation. Serostatus disclosure themes included disclosure to selective partners and personal responsibility. Comprehensive HIV risk-reduction strategies that build social support networks, condom self-efficacy, communication skills, and a sense of collective responsibility among NGI African American MSM/W while addressing HIV stigma in the African American community as a whole are suggested. PMID:16736115

  9. 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 (

  10. Determining If the Actions of African American Combat Forces during World War I Positively Affected the Employment of African American Combat Soldiers during World War II

    DTIC Science & Technology

    2007-06-15

    between such profitless systems of back breaking labor. This policy of separation did in fact prevent the proper equipping and management of African...financial prosperity. The fact that the army was still a proponent of the separate but “unequal” philosophy was accepted as an unfortunate status quo...The military was simply another American institution that subscribed to the 9 unorthodox quasi-scientific reasoning that hereditary biological

  11. 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

  12. Contemporary treatment of heart failure: is there adequate evidence to support a unique strategy for African-Americans? Con position.

    PubMed

    Ferdinand, Keith C; Serrano, Claudia C; Ferdinand, Daphne P

    2002-08-01

    Heart failure is a substantial cause of increased morbidity and mortality in the African-American population, with poorer prognosis versus white patients. Systolic heart failure is predominantly caused by poorly controlled hypertension in African-Americans. Overall, African-Americans remain underrepresented in morbidity and mortality heart failure trials, and further data are needed to confirm the potential benefit of present therapies and newer approaches to heart failure in African-Americans. Intensive blood pressure control and control of other risk factors, along with the appropriate application of evidence-based therapies including angiotensin converting enzyme (ACE) inhibitors and approved beta-blockers, are required to decrease racial disparities. Although some data suggest that contemporary treatment with ACE inhibitors and beta-blockers may be less effective in African-Americans in terms of reducing heart failure morbidity and mortality, there is not adequate evidence to support a unique strategy for this population. The use of evidence-based therapies should be equally applied to African-Americans as well as to other ethnic groups while awaiting further studies.

  13. 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…

  14. 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.

  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. Noma (cancrum oris): case report in a 4-year-old HIV-positive South African child.

    PubMed

    Naidoo, S; Chikte, U M

    2000-12-01

    Cancrum oris (noma) is a gangrenous infection that develops in the mouth and spreads rapidly to other parts of the face. The disease occurs mostly in conditions of poverty, poor hygiene and malnutrition. In sub-Saharan Africa the frequency in several countries is estimated to be 1-7 cases per 1,000 population, and as many as 12 cases per 1,000 in the most affected communities. About 90% of these children die without receiving any care, yet the disease can, and should, be prevented. With increasing numbers of children who are malnourished and who have compromised immune systems (compounded by the HIV pandemic) the prevalence of conditions such as noma is likely to increase. Among the earliest features of noma are excessive salivation, marked fetor oris, facial oedema and a greyish-black discolouration of the skin in the affected area. This devastating gangrenous lesion may involve the cheek, the chin, the infra-orbital margin, palate, nose, antrum and virtually any part of the face. This report describes a 4-year-old HIV-positive African girl, who was abandoned, discharged from the Plastics Unit and now lives in a child care sanctuary. Little is known about her history prior to her arrival at the home a few weeks previously. The clinical examination revealed a delay in growth and physical development equivalent to that of a 2-year-old child. The left cheek had a perforating ulcer in a healing phase. The perforation, about 1 cm in diameter, was surrounded by oedematous tissues showing a mild to moderate erythema. The peripheral oedema extended to the lower palpebral, the upper labial, left labial commissural, mandibular and pre-parotid regions. Submental, submandibular and cervical lymph nodes were mildly painful upon palpation. The child was not pyretic. The intra-oral examination revealed the features of acute necrotising gingivitis (ANG). ANG was generalised and showed classic interdental crater-like ulcers covered with whitish debris. Halitosis was pronounced

  17. 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…

  18. 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.

  19. 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.

  20. The genetic structure and history of Africans and African Americans.

    PubMed

    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

    2009-05-22

    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 (approximately 71%), European (approximately 13%), and other African (approximately 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.

  1. The Protective Role of the Family and Social Support Network in a Sample of HIV-Positive African American Women: Results of a Pilot Study

    PubMed Central

    Robbins, Michael; Szapocznik, José; Tejeda, Manuel; Samuels, Deanne; Ironson, Gail; Antoni, Michael

    2005-01-01

    This study examined the role of family functioning and social support in protecting HIV-positive African American women from the adverse psychological consequences associated with deterioration in their CD4 cell count. Participants were 38 African American HIV-positive women who had recently given birth. Results demonstrated that changes in CD4 cell counts were inversely predictive of psychological distress and were moderated by family functioning and social support satisfaction. Women with good family functioning were less affected by changes in their CD4 cell counts, and women with poor family functioning were more emotionally responsive to changes in CD4 cell count. Unexpectedly, women from families where conflicts tended to be clearly laid out and discussed were also more responsive to both changes in CD4 cell counts. Interventions are recommended that increase a client’s social support satisfaction, foster an adaptive level of connectedness to family, and enhance the family’s range of conflict resolution styles. PMID:16609750

  2. Do People Know I’m Poz?: Factors Associated with Knowledge of Serostatus among HIV-positive African Americans’ Social Network Members

    PubMed Central

    Hoover, Matthew A.; Green, Harold D.; Bogart, Laura M.; Wagner, Glenn J.; Mutchler, Matt G.; Galvan, Frank H.; McDavitt, Bryce

    2015-01-01

    We examined how functional social support, HIV-related discrimination, internalized HIV stigma, and social network structure and composition were cross-sectionally associated with network members’ knowledge of respondents’ serostatus among 244 HIV-positive African Americans in Los Angeles. Results of a generalized hierarchical linear model indicated people in respondents’ networks who were highly trusted, well-known to others (high degree centrality), HIV-positive, or sex partners were more likely to know respondents’ HIV serostatus; African American network members were less likely to know respondents’ serostatus, as were drug-using partners. Greater internalized stigma among respondents living with HIV was associated with less knowledge of their seropositivity within their social network whereas greater respondent-level HIV discrimination was associated with more knowledge of seropositivity within the network. Additional research is needed to understand the causal mechanisms and mediating processes associated with serostatus disclosure as well as the long-term consequences of disclosure and network members’ knowledge of respondents’ serostatus. PMID:25903505

  3. Do People Know I'm Poz?: Factors Associated with Knowledge of Serostatus Among HIV-Positive African Americans' Social Network Members.

    PubMed

    Hoover, Matthew A; Green, Harold D; Bogart, Laura M; Wagner, Glenn J; Mutchler, Matt G; Galvan, Frank H; McDavitt, Bryce

    2016-01-01

    We examined how functional social support, HIV-related discrimination, internalized HIV stigma, and social network structure and composition were cross-sectionally associated with network members' knowledge of respondents' serostatus among 244 HIV-positive African Americans in Los Angeles. Results of a generalized hierarchical linear model indicated people in respondents' networks who were highly trusted, well-known to others (high degree centrality), HIV-positive, or sex partners were more likely to know respondents' HIV serostatus; African American network members were less likely to know respondents' serostatus, as were drug-using partners. Greater internalized stigma among respondents living with HIV was associated with less knowledge of their seropositivity within their social network whereas greater respondent-level HIV discrimination was associated with more knowledge of seropositivity within the network. Additional research is needed to understand the causal mechanisms and mediating processes associated with serostatus disclosure as well as the long-term consequences of disclosure and network members' knowledge of respondents' serostatus.

  4. Positive practice environments influence job satisfaction of primary health care clinic nursing managers in two South African provinces

    PubMed Central

    2014-01-01

    Background Nurses constitute the majority of the health workforce in South Africa and they play a major role in providing primary health care (PHC) services. Job satisfaction influences nurse retention and successful implementation of health system reforms. This study was conducted in light of renewed government commitment to reforms at the PHC level, and to contribute to the development of solutions to the challenges faced by the South African nursing workforce. The objective of the study was to determine overall job satisfaction of PHC clinic nursing managers and the predictors of their job satisfaction in two South African provinces. Methods During 2012, a cross-sectional study was conducted in two South African provinces. Stratified random sampling was used to survey a total of 111 nursing managers working in PHC clinics. These managers completed a pre-tested Measure of Job Satisfaction questionnaire with subscales on personal satisfaction, workload, professional support, training, pay, career prospects and standards of care. Mean scores were used to measure overall job satisfaction and various subscales. Predictors of job satisfaction were determined through multiple logistic regression analysis. Results A total of 108 nursing managers completed the survey representing a 97% response rate. The mean age of respondents was 49 years (SD = 7.9) and the majority of them (92%) were female. Seventy-six percent had a PHC clinical training qualification. Overall mean job satisfaction scores were 142.80 (SD = 24.3) and 143.41 (SD = 25.6) for Gauteng and Free State provinces respectively out of a maximum possible score of 215. Predictors of job satisfaction were: working in a clinic of choice (RRR = 3.10 (95% CI: 1.11 to 8.62, P = 0.030)), being tired at work (RRR = 0.19 (95% CI: 0.08 to 0.50, P = 0.001)) and experience of verbal abuse (RRR = 0.18 (95% CI: 0.06 to 0.55, P = 0.001). Conclusion Allowing nurses greater choice of clinic

  5. 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

  6. A Qualitative Study of African-American Female Administrators in the Academy: Identification of Characteristics That Contribute to Their Advancement to Senior Level Positions of Authority

    ERIC Educational Resources Information Center

    Alexander-Lee, Mary Louise

    2014-01-01

    The qualitative study explored the (a) self-identity and individual experiences of five African American female higher education administrators, (b) educational and background preparedness of each African American female administrator, (c) individual support mechanisms of each African American female administrator, (i.e., mentoring, community and…

  7. The impact of Atlas Mountain cold-pool events on the position and intensity of the summertime West African heat low

    NASA Astrophysics Data System (ADS)

    Schuster, Robert; Fink, Andreas H.; Knippertz, Peter; Marsham, John H.; Parker, Douglas J.; Flamant, Cyrille

    2014-05-01

    Recently discovered fluctuations of the summertime West African heat low on different time scales are still not fully understood, but of major importance for an improved prediction of the West African Monsoon system in weather and climate models. It has recently been demonstrated that the cold-pool outflows from convection form a significant component of the West African monsoon and that in a global model the failure to represent these adequately is a major cause of thermodynamic model-bias in the monsoon-ventilated heat-low region. Here we focus on the extratropical flank of the heat low, which often reaches to the Saharan foothills of the Atlas Mountains in Morocco and Algeria during the summer months. Strong, often orographically triggered convective events over the Atlas Mountains and at their southern flanks are a regularly observed feature during this time. Such events are often associated with evaporatively driven cold-pools, resulting in haboob dust storms in the Saharan Desert. The leading edge of these density currents can reach lengths of several hundreds to a thousand kilometres; its movement is visible on satellite images for up to twelve hours and affects the core region of the heat low. Significant amounts of moisture are transported into the desert this way and can lead to the production of new convective systems there. We use the Weather Research and Forecast (WRF) model driven by the operational analysis of the European Centre for Medium-Range Weather Forecasting (ECMWF) to investigate the impact of these events on the positions and strength of the heat low in convection-permitting simulations. The aim is to improve the understanding of the involved processes and to quantify the errors that are expected in models that are not able to generate cold pools effectively due to their parametrisations of moist convection. The cases used for this study have been selected based on station measurements and on infrared as well as microwave satellite data

  8. The Social Patterning of Sleep in African Americans: Associations of Socioeconomic Position and Neighborhood Characteristics with Sleep in the Jackson Heart Study

    PubMed Central

    Johnson, Dayna A.; Lisabeth, Lynda; Hickson, DeMarc; Johnson-Lawrence, Vicki; Samdarshi, Tandaw; Taylor, Herman; Diez Roux, Ana V.

    2016-01-01

    Study Objectives: We investigated cross-sectional associations of individual-level socioeconomic position (SEP) and neighborhood characteristics (social cohesion, violence, problems, disadvantage) with sleep duration and sleep quality in 5,301 African Americans in the Jackson Heart Study. Methods: All measures were self-reported. Sleep duration was assessed as hours of sleep; sleep quality was reported as poor (1) to excellent (5). SEP was measured by categorized years of education and income. Multinomial logistic and linear regression models were fit to examine the associations of SEP and neighborhood characteristics (modeled dichotomously and tertiles) with sleep duration (short vs. normal, long vs. normal) and continuous sleep duration and quality after adjustment for demographics and risk factors. Results: The mean sleep duration was 6.4 ± 1.5 hours, 54% had a short (≤ 6 h) sleep duration, 5% reported long (≥ 9 h) sleep duration, and 24% reported fair to poor sleep quality. Lower education was associated with greater odds of long sleep (odds ratio [OR] = 2.19, 95% confidence interval [CI] = 1.42, 3.38) and poorer sleep quality (β = −0.17, 95% CI = −0.27, −0.07) compared to higher education after adjustment for demographics and risk factors. Findings were similar for income. High neighborhood violence was associated with shorter sleep duration (−9.82 minutes, 95% CI = −16.98, −2.66) and poorer sleep quality (β = −0.11, 95% CI = −0.20, 0.00) after adjustment for demographics and risk factors. Results were similar for neighborhood problems. In secondary analyses adjusted for depressive symptoms in a subset of participants, most associations were attenuated and only associations of low SEP with higher odds of long sleep and higher neighborhood violence with poorer sleep quality remained statistically significant. Conclusions: Social and environmental characteristics are associated with sleep duration and quality in African Americans

  9. Recommendations for the management of idiopathic pulmonary fibrosis in South Africa: a position statement of the South African Thoracic Society

    PubMed Central

    Ainslie, Gillian M.; Dheda, Keertan; Allwood, Brian W.; Wong, Michelle L.; Lalloo, Umesh G.; Abdool-Gaffar, Mohamed S.; Khalfey, Hoosain; Irusen, Elvis M.

    2016-01-01

    Idiopathic pulmonary fibrosis (IPF) is a very specific form of a chronic, progressive fibroproliferative interstitial pneumonia of unknown aetiology. The disease is generally associated with a poor prognosis. Several international evidence-based guidelines on the diagnosis and management of IPF and other interstitial lung diseases (ILDs) have been published and updated in the last decade, and while the body of evidence for the use of some treatment modalities has grown, others have been shown to be futile and even harmful to patients. In a patient who presents with the classic clinical features, restrictive ventilatory impairment with impaired diffusion and a high resolution computed tomography (HRCT) scan of the lungs showing a usual interstitial pneumonia (UIP) pattern, a definitive diagnosis of IPF can be made, provided all other causes of a radiological UIP pattern are excluded. Patients who present with atypical clinical features or an HRCT pattern classified as “possible” UIP, should be referred for a surgical lung biopsy. Once the diagnosis of IPF is confirmed, a patient-centred approached should be followed, as the stage of the disease, degree of impairment, rate of disease progression, comorbid illnesses and patient preferences all impact on long-term management. The South African Thoracic Society (SATS) suggests that anti-fibrotic treatment should be offered to appropriate candidates [confirmed IPF with a forced vital capacity (FVC) of 50–80%], but discontinued should there be evidence of disease progression (a decline in FVC of ≥10% within any 12-month period). The routine use of high dose oral steroids, immunosuppressive drugs and anticoagulants is not recommended whilst anti-acid therapy may be considered in patients without advanced disease. PMID:28149568

  10. 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.

  11. 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…

  12. A diffusion tensor imaging and neuropsychological study of prospective memory impairment in South African HIV positive individuals.

    PubMed

    Hoare, Jacqueline; Jacqueline, Hoare; Westgarth-Taylor, Jenny; Jenny, Westgarth-Taylor; Fouche, Jean-Paul; Jean-Paul, Fouche; Spottiswoode, Bruce; Bruce, Spottiswoode; Paul, Robert; Robert, Paul; Thomas, Kevin; Kevin, Thomas; Stein, Dan; Dan, Stein; Joska, John; John, Joska

    2012-09-01

    HIV-associated prospective memory (ProM) impairment has emerged, in earlier studies as a significant predictor of medication management and independence in activities of daily living. The relationship between ProM and white matter integrity in HIV has not previously been investigated. Participants, including 128 HIV-infected individuals and 32 healthy controls, were assessed using a comprehensive neuropsychological evaluation and both objective and subjective measures of ProM. Diffusion tensor imaging (DTI) was utilized to investigate the relationship of white matter integrity to ProM in a randomly selected subsample of 40 HIV positive subjects, using a whole brain voxel-based approach to define fractional anisotrophy (FA) and mean diffusion (MD). Total prospective memory was significantly poorer in the HIV positive group when compared with healthy controls (p = 0.023). Time-based ProM was poorer in the HIV group compared to healthy controls both without prompts (p = 0.001) and with prompts (p = 0.001). Poor Total ProM score correlated with performance on neuropsychological tests of executive functioning, information processing speed, learning, and working memory (p < 0.05). Those HIV positive participants with poor ProM had significantly decreased FA in the regions of superior corona radiata (p = 0.0035), the corpus collosum (p = 0.006) and the cingulum (p = 0.0033) when compared to those who were HIV positive with good ProM. This study reinforces the importance of ProM assessment in HIV.

  13. Positive Selection of Deleterious Alleles through Interaction with a Sex-Ratio Suppressor Gene in African Buffalo: A Plausible New Mechanism for a High Frequency Anomaly

    PubMed Central

    van Hooft, Pim; Greyling, Ben J.; Getz, Wayne M.; van Helden, Paul D.; Zwaan, Bas J.; Bastos, Armanda D. S.

    2014-01-01

    Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important

  14. Positive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African Buffalo: a plausible new mechanism for a high frequency anomaly.

    PubMed

    van Hooft, Pim; Greyling, Ben J; Getz, Wayne M; van Helden, Paul D; Zwaan, Bas J; Bastos, Armanda D S

    2014-01-01

    Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important

  15. My Sister, Myself: The Identification of Sociocultural Factors That Affect the Advancement of African-American Women into Senior-Level Administrative Positions

    ERIC Educational Resources Information Center

    Candia-Bailey, Antoinette Bonnie

    2016-01-01

    Since the 1800s African-American women have been involved in educational processes in meaningful ways despite challenges to their efforts and advancements. African-American women have made significant strides in breaking the glass ceiling within higher education. This qualitative research study explores and compares the perceptions of challenges…

  16. Approximation algorithms

    PubMed Central

    Schulz, Andreas S.; Shmoys, David B.; Williamson, David P.

    1997-01-01

    Increasing global competition, rapidly changing markets, and greater consumer awareness have altered the way in which corporations do business. To become more efficient, many industries have sought to model some operational aspects by gigantic optimization problems. It is not atypical to encounter models that capture 106 separate “yes” or “no” decisions to be made. Although one could, in principle, try all 2106 possible solutions to find the optimal one, such a method would be impractically slow. Unfortunately, for most of these models, no algorithms are known that find optimal solutions with reasonable computation times. Typically, industry must rely on solutions of unguaranteed quality that are constructed in an ad hoc manner. Fortunately, for some of these models there are good approximation algorithms: algorithms that produce solutions quickly that are provably close to optimal. Over the past 6 years, there has been a sequence of major breakthroughs in our understanding of the design of approximation algorithms and of limits to obtaining such performance guarantees; this area has been one of the most flourishing areas of discrete mathematics and theoretical computer science. PMID:9370525

  17. 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.

  18. 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.

  19. Associations between HIV-related stigma, racial discrimination, gender discrimination, and depression among HIV-positive African, Caribbean, and Black women in Ontario, Canada.

    PubMed

    Logie, Carmen; James, Llana; Tharao, Wangari; Loutfy, Mona

    2013-02-01

    Abstract African, Caribbean, and Black (ACB) women are greatly overrepresented in new HIV infections in comparison with Canada's general population. Social and structural factors such as HIV-related stigma, gender discrimination, and racial discrimination converge to increase vulnerability to HIV infection among ACB women by reducing access to HIV prevention services. Stigma and discrimination also present barriers to treatment, care, and support and may contribute to mental health problems. We administered a cross-sectional survey to HIV-positive ACB women (n=173) across Ontario in order to examine the relationships between HIV-related stigma, gender discrimination, racial discrimination, and depression. One-third of participants reported moderate/severe depression scores using the Beck Depression Inventory Fast-Screen guidelines. Hierarchical block regression, moderation, and mediation analyses were conducted to measure associations between independent (HIV-related stigma, gender discrimination, racial discrimination), moderator/mediator (social support, resilient coping), and dependent (depression) variables. Findings included: (1) HIV-related stigma was associated with increased depression; (2) resilient coping was associated with reduced depression but did not moderate the influence of HIV-related stigma on depression; and (3) the effects of HIV-related stigma on depression were partially mediated through resilient coping. HIV-related stigma, gender discrimination, and racial discrimination were significantly correlated with one another and with depression, highlighting the salience of examining multiple intersecting forms of stigma. Generalizability of findings may be limited due to nonrandom sampling. Findings emphasize the importance of multi-component interventions, including building resilient coping skills, mental health promotion and assessment, and stigma reduction programs.

  20. 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.

  1. African American Administrators and Staff

    ERIC Educational Resources Information Center

    Wright, Dianne; Taylor, Janice D.; Burrell, Charlotte; Stewart, Gregory

    2006-01-01

    This article explores the issues of African American participation in the administrative ranks of the academy. The authors find that African Americans tend to hold positions that are marginal in academic organizations, lacking power and influence, and that not much has changed over recent decades. Forces influencing this condition are explored,…

  2. 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…

  3. African American Teaching and the Matriarchal Performance.

    ERIC Educational Resources Information Center

    Jeffries, Rhonda Baynes

    This paper discusses the role of matriarchs in African-American culture, explaining that traditionally, African-American matriarchs arise from a combination of African norms and American social positions that naturally forces them to assume leadership conditions. The roles these women assume are a response to the desire to survive in a society…

  4. 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

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

    PubMed

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

    2012-02-01

    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.

  6. Ectoparasites of African Mammals.

    DTIC Science & Technology

    1976-11-30

    This study consisted of ectoparasites from approximately 100,000 African small mammals, representing probably more than 500 species of which many are...study of ectoparasites may provide information concerning interactions among animal reservoirs of disease, and (3) an understanding of ecological...parameters for ectoparasites and their hosts may enhance understanding of epidemiological patterns. Of the four major groups dealt with, considerably more

  7. [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.

  8. 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

  9. 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

  10. Concealment, communication and stigma: The perspectives of HIV-positive immigrant Black African men and their partners living in the United Kingdom.

    PubMed

    Owuor, John Oa; Locke, Abigail; Heyman, Bob; Clifton, Andrew

    2016-12-01

    This study explored the perspectives of Black men, originally from East Africa, living in the United Kingdom and their partners on what it means to live with diagnosed HIV. This article reports on concealment of HIV-positive status as a strategy adopted by the affected participants to manage the flow of information about their HIV-positive status. Analysis of the data, collected using in-depth interviews involving 23 participants, found widespread selective concealment of HIV-positive status. However, a few respondents had 'come out' publicly about their condition. HIV prevention initiatives should recognise concealment as a vital strategy in managing communication about one's HIV-positive status.

  11. Interpolation and Approximation Theory.

    ERIC Educational Resources Information Center

    Kaijser, Sten

    1991-01-01

    Introduced are the basic ideas of interpolation and approximation theory through a combination of theory and exercises written for extramural education at the university level. Topics treated are spline methods, Lagrange interpolation, trigonometric approximation, Fourier series, and polynomial approximation. (MDH)

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

    PubMed

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

    2009-12-01

    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 maintenance of these positive self-views. In this paper, we evaluate these arguments using data drawn from a panel study of socio-economically diverse African American adolescent girls living in Iowa and Georgia. We analyze the relationship between body size and social self-image over three waves of data, starting when the girls were 10 years of age and concluding when they were approximately 14. We find that heavier respondents hold less positive social self-images but also find that being raised in a family that practices racial socialization moderates this relationship.

  13. 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…

  14. African Pentecostalism

    ERIC Educational Resources Information Center

    Garrard, David J.

    2009-01-01

    The diversity of African Pentecostalism, its early colonial and missionary history and its current characteristics are described and analysed. Reference is made to methods of training and forms of leadership, and suggestions are made about the reasons for its growth and persistence. (Contains 19 notes.)

  15. African-American Biography.

    ERIC Educational Resources Information Center

    Martin, Ron

    1995-01-01

    Suggests sources of information for African American History Month for library media specialists who work with students in grades four through eight. Gale Research's "African-American Reference Library," which includes "African-America Biography,""African-American Chronology," and "African-American Almanac,"…

  16. 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.

  17. African Trypanosomiasis

    DTIC Science & Technology

    2011-06-01

    infection by protozoan hemo- flagellates of the Trypanosoma brucei complex, 2 subspe- cies of which cause disease in humans: Trypanosoma bru- cei gambiense...public release; distribution unlimited 13. SUPPLEMENTARY NOTES See also ADA545141. Chapter 3 from e-book, Topics on the Pathology of Protozoan and...the brief ferry crossing. 2 3 • Topics on The paThology of proTozoan and invasive arThropod diseases Three severe epidemics of African trypanosomiasis

  18. 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…

  19. 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…

  20. 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.

  1. Approximation of Laws

    NASA Astrophysics Data System (ADS)

    Niiniluoto, Ilkka

    2014-03-01

    Approximation of laws is an important theme in the philosophy of science. If we can make sense of the idea that two scientific laws are "close" to each other, then we can also analyze such methodological notions as approximate explanation of laws, approximate reduction of theories, approximate empirical success of theories, and approximate truth of laws. Proposals for measuring the distance between quantitative scientific laws were given in Niiniluoto (1982, 1987). In this paper, these definitions are reconsidered as a response to the interesting critical remarks by Liu (1999).

  2. Racial socialization and racial identity: African American parents' messages about race as precursors to identity.

    PubMed

    Neblett, Enrique W; Smalls, Ciara P; Ford, Kahlil R; Nguyên, Hòa X; Sellers, Robert M

    2009-02-01

    This study uses two waves of data to examine the relationships among patterns of racial socialization experiences and racial identity in a sample of 358 African American adolescents (60% female and 40% male). Using latent class analyses, we identified three patterns of adolescent-reported racial socialization experiences: High Positive, Moderate Positive, and Low Frequency. Adolescent-reported racial socialization experiences at Wave 1 were associated with Wave 2 adolescent racial identity approximately one year later. Specifically, High Positive and Low Frequency racial socialization were associated with racial centrality, assimilationist ideology, and nationalist ideology. These findings suggest that various patterns of racial socialization practices play an important role in the developing significance and meaning that African American adolescents ascribe to race.

  3. 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

  4. 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.

  5. 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

  6. 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…

  7. 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…

  8. 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.

  9. Green Ampt approximations

    NASA Astrophysics Data System (ADS)

    Barry, D. A.; Parlange, J.-Y.; Li, L.; Jeng, D.-S.; Crapper, M.

    2005-10-01

    The solution to the Green and Ampt infiltration equation is expressible in terms of the Lambert W-1 function. Approximations for Green and Ampt infiltration are thus derivable from approximations for the W-1 function and vice versa. An infinite family of asymptotic expansions to W-1 is presented. Although these expansions do not converge near the branch point of the W function (corresponds to Green-Ampt infiltration with immediate ponding), a method is presented for approximating W-1 that is exact at the branch point and asymptotically, with interpolation between these limits. Some existing and several new simple and compact yet robust approximations applicable to Green-Ampt infiltration and flux are presented, the most accurate of which has a maximum relative error of 5 × 10 -5%. This error is orders of magnitude lower than any existing analytical approximations.

  10. 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.

  11. 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.

  12. 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.

  13. Intrinsic Nilpotent Approximation.

    DTIC Science & Technology

    1985-06-01

    RD-A1II58 265 INTRINSIC NILPOTENT APPROXIMATION(U) MASSACHUSETTS INST 1/2 OF TECH CAMBRIDGE LAB FOR INFORMATION AND, DECISION UMCLRSSI SYSTEMS C...TYPE OF REPORT & PERIOD COVERED Intrinsic Nilpotent Approximation Technical Report 6. PERFORMING ORG. REPORT NUMBER LIDS-R-1482 7. AUTHOR(.) S...certain infinite-dimensional filtered Lie algebras L by (finite-dimensional) graded nilpotent Lie algebras or g . where x E M, (x,,Z) E T*M/O. It

  14. Anomalous diffraction approximation limits

    NASA Astrophysics Data System (ADS)

    Videen, Gorden; Chýlek, Petr

    It has been reported in a recent article [Liu, C., Jonas, P.R., Saunders, C.P.R., 1996. Accuracy of the anomalous diffraction approximation to light scattering by column-like ice crystals. Atmos. Res., 41, pp. 63-69] that the anomalous diffraction approximation (ADA) accuracy does not depend on particle refractive index, but instead is dependent on the particle size parameter. Since this is at odds with previous research, we thought these results warranted further discussion.

  15. 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.

  16. 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.

  17. 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…

  18. 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.

  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. On Stochastic Approximation.

    ERIC Educational Resources Information Center

    Wolff, Hans

    This paper deals with a stochastic process for the approximation of the root of a regression equation. This process was first suggested by Robbins and Monro. The main result here is a necessary and sufficient condition on the iteration coefficients for convergence of the process (convergence with probability one and convergence in the quadratic…

  1. 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…

  2. African Americans and Glaucoma

    MedlinePlus

    ... Involved News About Us Donate In This Section African Americans and Glaucoma email Send this article to a ... glaucoma is the leading cause of blindness in African Americans. Half of those with glaucoma don't know ...

  3. 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)

  4. Managing the hair and skin of African American pediatric patients.

    PubMed

    Smith, W; Burns, C

    1999-01-01

    In Africa, the ancestral home of most African Americans, hair is viewed as the epitome of beauty. However, when Africans were brought to America as slaves, they were unable to care for their hair and skin adequately and were exposed to the predominant white culture, which valued straight hair and light skin. As a result, many African Americans lost self-esteem because of the characteristics of their hair and skin. In this article we examine the anatomic and physiologic features of African American hair and skin and typical African American hair and skin care practices. Common African American hair and skin disorders and their management are discussed. The goal of this article is to help primary care providers understand the special hair and skin care required for African American children (as well as other dark-skinned patients). With good patient education, understanding one's own hair and skin characteristics can also support positive self-esteem.

  5. HMO employment and African-American physicians.

    PubMed Central

    Briscoe, Forrest; Konrad, Thomas R.

    2006-01-01

    OBJECTIVES: To assess the level and determinants of African-American physicians' employment in health maintenance organizations (HMOs), particularly early in their careers. METHODS: We analyzed data from the 1991 and 1996 Young Physicians Surveys to assess racial differences in the likelihood of HMO employment (n = 3,705). Using multinomial logistic regression, we evaluated four explanations for an observed relationship between African-American physicians and HMO employment: human capital stratification among organizations, race-based affinity between physicians and patients, financial constraints due to debt burden, and different organizational hiring practices. Using binomial logistic regression, we also evaluated differences in the odds of being turned down for a prior practice position, of subsequently leaving the current practice organization and of later having career doubts. RESULTS: Without any controls, African-American physicians were 4.52 times more likely to practice in HMOs than Caucasian physicians. After controlling for human capital stratification, racial concordance and financial constraints, African-American physicians remained 2.48 times more likely to practice in HMOs than Caucasian physicians. In addition, 19.2% of African-American physicians in HMOs reported being turned down for another job, far more than any other racial/ethnic group in the HMO setting and any racial/ethnic group, including African-American physicians in the non-HMO setting (including all other practice locations). Five years later, those same African-American physicians from HMOs also reported significantly more turnover (7.50 times more likely than non-HMO African-American physicians to leave their current practice) and doubt about their careers (2.17 times more likely than non-HMO African-American physicians to express serious career doubts). CONCLUSIONS: African-American physicians were disproportionately hired into HMO settings, impacting their subsequent careers. PMID

  6. The TG/HDL-C ratio does not predict insulin resistance in overweight women of African descent: a study of South African, African American and West African women.

    PubMed

    Knight, Michael G; Goedecke, Julia H; Ricks, Madia; Evans, Juliet; Levitt, Naomi S; Tulloch-Reid, Marshall K; Sumner, Anne E

    2011-01-01

    Women of African descent have a high prevalence of diseases caused by insulin resistance. To positively impact cardiometabolic health in Black women, effective screening tests for insulin resistance must be identified. Recently, the TG/HDL-C ratio has been recommended as a tool to predict insulin resistance in overweight people. While the ratio predicts insulin resistance in White women, it is ineffective in African American women. As there are no data for African women, we tested the ability of the TG/HDL-C ratio to predict insulin resistance in Black women from South Africa, West Africa and the United States. For comparison, the ratio was also tested in White women from South Africa. Participants were 801 women (157 Black South African, 382 African American, 119 West African, 143 White South African, age 36 +/- 9y [mean +/- SD]). Standardized scores were created from log-transformed homeostasis model assessment-insulin resistance values from each population. Participants in the upper third of their population distribution were classified as insulin-resistant. To predict insulin resistance by the TC/HDL-C ratio, area under the receiver operating characteristic (AUC-ROC) curve was used and criteria were: 0.50 for no discrimination and > or = 0.70 for acceptable. Seventy-one percent of the Black women were overweight vs 51% of White women (P<.01). In overweight White women, AUC-ROC curve for prediction of insulin resistance by TG/HDL-C was 0.76 +/- 0.06, but below the 0.70 threshold in each group of overweight Black women (Black South African: 0.64 +/- 0.06, African American: 0.66 +/- 0.03, and West African: 0.63 +/- 0.07). Therefore, TG/HDL-C does not predict insulin resistance in overweight African American women and this investigation extends that finding to overweight Black South African and West African women. Resources to identify effective markers of insulin resistance are needed to improve cardiometabolic health in women of African descent.

  7. 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…

  8. Applied Routh approximation

    NASA Technical Reports Server (NTRS)

    Merrill, W. C.

    1978-01-01

    The Routh approximation technique for reducing the complexity of system models was applied in the frequency domain to a 16th order, state variable model of the F100 engine and to a 43d order, transfer function model of a launch vehicle boost pump pressure regulator. The results motivate extending the frequency domain formulation of the Routh method to the time domain in order to handle the state variable formulation directly. The time domain formulation was derived and a characterization that specifies all possible Routh similarity transformations was given. The characterization was computed by solving two eigenvalue-eigenvector problems. The application of the time domain Routh technique to the state variable engine model is described, and some results are given. Additional computational problems are discussed, including an optimization procedure that can improve the approximation accuracy by taking advantage of the transformation characterization.

  9. Topics in Metric Approximation

    NASA Astrophysics Data System (ADS)

    Leeb, William Edward

    This thesis develops effective approximations of certain metrics that occur frequently in pure and applied mathematics. We show that distances that often arise in applications, such as the Earth Mover's Distance between two probability measures, can be approximated by easily computed formulas for a wide variety of ground distances. We develop simple and easily computed characterizations both of norms measuring a function's regularity -- such as the Lipschitz norm -- and of their duals. We are particularly concerned with the tensor product of metric spaces, where the natural notion of regularity is not the Lipschitz condition but the mixed Lipschitz condition. A theme that runs throughout this thesis is that snowflake metrics (metrics raised to a power less than 1) are often better-behaved than ordinary metrics. For example, we show that snowflake metrics on finite spaces can be approximated by the average of tree metrics with a distortion bounded by intrinsic geometric characteristics of the space and not the number of points. Many of the metrics for which we characterize the Lipschitz space and its dual are snowflake metrics. We also present applications of the characterization of certain regularity norms to the problem of recovering a matrix that has been corrupted by noise. We are able to achieve an optimal rate of recovery for certain families of matrices by exploiting the relationship between mixed-variable regularity conditions and the decay of a function's coefficients in a certain orthonormal basis.

  10. 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

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

    PubMed

    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.

  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. Approximate Qualitative Temporal Reasoning

    DTIC Science & Technology

    2001-01-01

    i.e., their boundaries can be placed in such a way that they coincide with the cell boundaries of the appropriate partition of the time-line. (Think of...respect to some appropriate partition of the time-line. For example, I felt well on Saturday. When I measured my temperature I had a fever on Monday and on...Bittner / Approximate Qualitative Temporal Reasoning 49 [27] I. A. Goralwalla, Y. Leontiev , M. T. Özsu, D. Szafron, and C. Combi. Temporal granularity for

  14. Hierarchical Approximate Bayesian Computation

    PubMed Central

    Turner, Brandon M.; Van Zandt, Trisha

    2013-01-01

    Approximate Bayesian computation (ABC) is a powerful technique for estimating the posterior distribution of a model’s parameters. It is especially important when the model to be fit has no explicit likelihood function, which happens for computational (or simulation-based) models such as those that are popular in cognitive neuroscience and other areas in psychology. However, ABC is usually applied only to models with few parameters. Extending ABC to hierarchical models has been difficult because high-dimensional hierarchical models add computational complexity that conventional ABC cannot accommodate. In this paper we summarize some current approaches for performing hierarchical ABC and introduce a new algorithm called Gibbs ABC. This new algorithm incorporates well-known Bayesian techniques to improve the accuracy and efficiency of the ABC approach for estimation of hierarchical models. We then use the Gibbs ABC algorithm to estimate the parameters of two models of signal detection, one with and one without a tractable likelihood function. PMID:24297436

  15. 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…

  16. 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…

  17. 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

  18. 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…

  19. 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.

  20. 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.

  1. 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

  2. Understanding African American Males

    ERIC Educational Resources Information Center

    Bell, Edward Earl

    2010-01-01

    The purpose of this study was to assess the socialization skills, self-esteem, and academic readiness of African American males in a school environment. Discussions with students and the School Perceptions Questionnaire provided data for this investigation. The intended targets for this investigation were African American students; however, there…

  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. 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…

  5. 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…

  6. 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…

  7. Population Genomics of sub-saharan Drosophila melanogaster: African diversity and non-African admixture.

    PubMed

    Pool, John E; Corbett-Detig, Russell B; Sugino, Ryuichi P; Stevens, Kristian A; Cardeno, Charis M; Crepeau, Marc W; Duchen, Pablo; Emerson, J J; Saelao, Perot; Begun, David J; Langley, Charles H

    2012-01-01

    Drosophila melanogaster has played a pivotal role in the development of modern population genetics. However, many basic questions regarding the demographic and adaptive history of this species remain unresolved. We report the genome sequencing of 139 wild-derived strains of D. melanogaster, representing 22 population samples from the sub-Saharan ancestral range of this species, along with one European population. Most genomes were sequenced above 25X depth from haploid embryos. Results indicated a pervasive influence of non-African admixture in many African populations, motivating the development and application of a novel admixture detection method. Admixture proportions varied among populations, with greater admixture in urban locations. Admixture levels also varied across the genome, with localized peaks and valleys suggestive of a non-neutral introgression process. Genomes from the same location differed starkly in ancestry, suggesting that isolation mechanisms may exist within African populations. After removing putatively admixed genomic segments, the greatest genetic diversity was observed in southern Africa (e.g. Zambia), while diversity in other populations was largely consistent with a geographic expansion from this potentially ancestral region. The European population showed different levels of diversity reduction on each chromosome arm, and some African populations displayed chromosome arm-specific diversity reductions. Inversions in the European sample were associated with strong elevations in diversity across chromosome arms. Genomic scans were conducted to identify loci that may represent targets of positive selection within an African population, between African populations, and between European and African populations. A disproportionate number of candidate selective sweep regions were located near genes with varied roles in gene regulation. Outliers for Europe-Africa F(ST) were found to be enriched in genomic regions of locally elevated

  8. Neotropical Africanized honey bees have African mitochondrial DNA.

    PubMed

    Smith, D R; Taylor, O R; Brown, W M

    1989-05-18

    Non-indigenous African honey bees have invaded most of South and Central America in just over 30 years. The genetic composition of this population and the means by which it rapidly colonizes new territory remain controversial. In particular, it has been unclear whether this 'Africanized' population has resulted from interbreeding between African and domestic European bees, or is an essentially pure African population. Also, it has not been known whether this population expanded primarily by female or by male migration. Restriction site mapping of 62 mitochondrial DNAs of African bees from Brazil, Venezuela and Mexico reveals that 97% were of African (Apis mellifera scutellata) type. Although neotropical European apiary populations are rapidly Africanized by mating with neotropical African males, there is little reciprocal gene flow to the neotropical African population through European females. These are the first genetic data to indicate that the neotropical African population could be expanding its range by female migration.

  9. DALI: Derivative Approximation for LIkelihoods

    NASA Astrophysics Data System (ADS)

    Sellentin, Elena

    2015-07-01

    DALI (Derivative Approximation for LIkelihoods) is a fast approximation of non-Gaussian likelihoods. It extends the Fisher Matrix in a straightforward way and allows for a wider range of posterior shapes. The code is written in C/C++.

  10. Phylogenomics of African guenons.

    PubMed

    Moulin, Sibyle; Gerbault-Seureau, Michèle; Dutrillaux, Bernard; Richard, Florence Anne

    2008-01-01

    The karyotypes of 28 specimens belonging to 26 species of Cercopithecinae have been compared with each other and with human karyotype by chromosome banding and, for some of them, by Zoo-FISH (human painting probes) techniques. The study includes the first description of the karyotypes of four species and a synonym of Cercopithecus nictitans. The chromosomal homologies obtained provide us with new data on a large number of rearrangements. This allows us to code chromosomal characters to draw Cercopithecini phylogenetic trees, which are compared to phylogenetic data based on DNA sequences. Our findings show that some of the superspecies proposed by Kingdon (1997 The Kingdon Field Guide to African Mammals, Academic Press.) and Groves (2001 Primates Taxonomy, Smithsonian Institution Press) do not form homogeneous groups and that the genus Cercopithecus is paraphyletic, in agreement with previous molecular analyses. The evolution of Cercopithecini karyotypes is mainly due to non-centromeric chromosome fissions and centromeric shifts or inversions. Non-Robertsonian translocations occurred in C. hamlyni and C. neglectus. The position of chromosomal rearrangements in the phylogenetic tree leads us to propose that the Cercopithecini evolution proceeded by either repeated fission events facilitated by peculiar genomic structures or successive reticulate phases, in which heterozygous populations for few rearranged chromosomes were present, allowing the spreading of chromosomal forms in various combinations, before the speciation process.

  11. Taylor Approximations and Definite Integrals

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.

    2007-01-01

    We investigate the possibility of approximating the value of a definite integral by approximating the integrand rather than using numerical methods to approximate the value of the definite integral. Particular cases considered include examples where the integral is improper, such as an elliptic integral. (Contains 4 tables and 2 figures.)

  12. Femtolensing: Beyond the semiclassical approximation

    NASA Technical Reports Server (NTRS)

    Ulmer, Andrew; Goodman, Jeremy

    1995-01-01

    Femtolensoing is a gravitational lensing effect in which the magnification is a function not only of the position and sizes of the source and lens, but also of the wavelength of light. Femtolensing is the only known effect of 10(exp -13) - 10(exp -16) solar mass) dark-matter objects and may possibly be detectable in cosmological gamma-ray burst spectra. We present a new and efficient algorithm for femtolensing calculation in general potentials. The physical optics results presented here differ at low frequencies from the semiclassical approximation, in which the flux is attributed to a finite number of mutually coherent images. At higher frequencies, our results agree well with the semicalssical predictions. Applying our method to a point-mass lens with external shear, we find complex events that have structure at both large and small spectral resolution. In this way, we show that femtolensing may be observable for lenses up to 10(exp -11) solar mass, much larger than previously believed. Additionally, we discuss the possibility of a search femtolensing of white dwarfs in the Large Magellanic Cloud at optical wavelengths.

  13. Conflict and human African trypanosomiasis.

    PubMed

    Berrang-Ford, Lea; Lundine, Jamie; Breau, Sebastien

    2011-02-01

    Human African Trypanosomiasis (HAT) has reemerged in sub-Saharan Africa as a disease of major public health importance. The success of HAT elimination in sub-Saharan Africa is subject to the feasibility of controlling, eliminating, or mitigating the determinants of incidence in affected countries. Conflict has been widely recognized and cited as a contributing factor to the resurgence of HAT in many countries, as well as to continuing HAT incidence in politically unstable and resource-poor regions. Despite extensive anecdotal and qualitative recognition of the role of conflict, there has been no quantitative research of this topic at the population level in affected African countries. We characterize the qualitative and quantitative associations between HAT incidence and conflict-related processes in HAT-affected African countries over the past 30 years. HAT and conflict-related data were collected for 35 affected countries in sub-Saharan Africa for the years 1976-2004. Descriptive and univariate inferential statistics, as well as negative binomial regression modeling, are used to assess the associations between HAT and conflict. A space-time scan statistic is used to identify significant incidence clusters. Clusters of HAT incidence over the past 30 years have predominantly coincided with periods of conflict or socio-political instability. HAT cases occurred significantly more often in countries and during years with conflict, high political terror, and internationalized civil war. The results indicate a lag period between the start of conflict events and a peak in incidence of approximately 10 years. We recommend explicit consideration and quantification of socio-political measures such as conflict and terror indices in GIS (Geographic Information Systems)-based risk assessments for HAT policy and intervention.

  14. Positional Identity and Science Teacher Professional Development

    ERIC Educational Resources Information Center

    Moore, Felicia M.

    2008-01-01

    The aim of this study was to understand the positional identity of three African American secondary science teachers. Positional identity was operationally defined in terms of race, ethnicity, economic status, gender, religion, and age. Positional identity was posited to inform why diverse teachers with differing knowledge and experiences in…

  15. 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. ...

  16. Obesity and African Americans

    MedlinePlus

    ... and Management System Report to Congress Knowledge Center Capacity Building Information Services Events Calendar Resource Guide Justice ... Workforce Diversity Grants Youth Program Grants Other Grants Planning and Evaluation Grantee Best Practices Black/African American ...

  17. Factors influencing prostate cancer screening in African American men.

    PubMed

    Lehto, Rebecca H; Song, Lixin; Stein, Karen F; Coleman-Burns, Patricia

    2010-10-01

    African American men have the highest prostate cancer incidence and mortality rates worldwide, but have lower screening rates compared with Caucasian men. The purpose of the study was to identify social ecological factors that affect screening behaviors in African American men, knowledge that could be integral to the design of culturally appropriate interventions. The exploratory study included 60 African American males recruited from the greater Detroit metropolitan area. Social ecological variables examined included age, marital status, presence of health insurance, education, health values and behaviors, physician trust, and perceived stress coping (John Henryism). Analyses included descriptives, chi-square tests, one-way ANOVAs, and logistic regression. Findings concluded that a parsimonious model consisting of two variables (age and health values) was predictive. African American males, > or =50 years, with higher positive health values were more likely to obtain screening. Findings imply the importance of health values and targeted educational and screening interventions for younger African American men.

  18. 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.

  19. Africanized honeybees are slower learners than their European counterparts

    PubMed Central

    DeGrandi-Hoffman, Gloria; Gronenberg, Wulfila

    2015-01-01

    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. PMID:19904521

  20. Africanized honeybees are slower learners than their European counterparts.

    PubMed

    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.

  1. Locus of control and peer relationships among Caucasian, Hispanic, Asian, and African American adolescents.

    PubMed

    Kang, Hannah Soo; Chang, Kyle Edward; Chen, Chuansheng; Greenberger, Ellen

    2015-01-01

    Past research has shown that locus of control plays an important role in a wide range of behaviors, such as academic achievement and positive social behaviors. However, little is known about whether locus of control plays the same role in minority adolescents' peer relationships. The current study examined ethnic differences in the associations between locus of control and peer relationships in early adolescence using samples from the Early Childhood Longitudinal Study (ECLS-K: 5,612 Caucasian, 1,562 Hispanic, 507 Asian, and 908 African-American adolescents) and the National Education Longitudinal Study (NELS: 8,484 Caucasian, 1,604 Hispanic, and 860 Asian, and 1,228 African American adolescents). Gender was approximately evenly split in both samples. The results from the two datasets were highly consistent. Significant interactions between ethnicity and locus of control indicated that having a more internal locus of control was particularly important for Caucasian students' peer relationships (ECLS-K) and social status (NELS), but less so for Asian, Hispanic, and African American students. Our findings suggest that the role of locus of control in peer relationship is contingent upon culture.

  2. Combining global and local approximations

    NASA Technical Reports Server (NTRS)

    Haftka, Raphael T.

    1991-01-01

    A method based on a linear approximation to a scaling factor, designated the 'global-local approximation' (GLA) method, is presented and shown capable of extending the range of usefulness of derivative-based approximations to a more refined model. The GLA approach refines the conventional scaling factor by means of a linearly varying, rather than constant, scaling factor. The capabilities of the method are demonstrated for a simple beam example with a crude and more refined FEM model.

  3. Combining global and local approximations

    SciTech Connect

    Haftka, R.T. )

    1991-09-01

    A method based on a linear approximation to a scaling factor, designated the 'global-local approximation' (GLA) method, is presented and shown capable of extending the range of usefulness of derivative-based approximations to a more refined model. The GLA approach refines the conventional scaling factor by means of a linearly varying, rather than constant, scaling factor. The capabilities of the method are demonstrated for a simple beam example with a crude and more refined FEM model. 6 refs.

  4. Phenomenological applications of rational approximants

    NASA Astrophysics Data System (ADS)

    Gonzàlez-Solís, Sergi; Masjuan, Pere

    2016-08-01

    We illustrate the powerfulness of Padé approximants (PAs) as a summation method and explore one of their extensions, the so-called quadratic approximant (QAs), to access both space- and (low-energy) time-like (TL) regions. As an introductory and pedagogical exercise, the function 1 zln(1 + z) is approximated by both kind of approximants. Then, PAs are applied to predict pseudoscalar meson Dalitz decays and to extract Vub from the semileptonic B → πℓνℓ decays. Finally, the π vector form factor in the TL region is explored using QAs.

  5. 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…

  6. 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…

  7. Perturbed kernel approximation on homogeneous manifolds

    NASA Astrophysics Data System (ADS)

    Levesley, J.; Sun, X.

    2007-02-01

    Current methods for interpolation and approximation within a native space rely heavily on the strict positive-definiteness of the underlying kernels. If the domains of approximation are the unit spheres in euclidean spaces, then zonal kernels (kernels that are invariant under the orthogonal group action) are strongly favored. In the implementation of these methods to handle real world problems, however, some or all of the symmetries and positive-definiteness may be lost in digitalization due to small random errors that occur unpredictably during various stages of the execution. Perturbation analysis is therefore needed to address the stability problem encountered. In this paper we study two kinds of perturbations of positive-definite kernels: small random perturbations and perturbations by Dunkl's intertwining operators [C. Dunkl, Y. Xu, Orthogonal polynomials of several variables, Encyclopedia of Mathematics and Its Applications, vol. 81, Cambridge University Press, Cambridge, 2001]. We show that with some reasonable assumptions, a small random perturbation of a strictly positive-definite kernel can still provide vehicles for interpolation and enjoy the same error estimates. We examine the actions of the Dunkl intertwining operators on zonal (strictly) positive-definite kernels on spheres. We show that the resulted kernels are (strictly) positive-definite on spheres of lower dimensions.

  8. "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…

  9. 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.

  10. Approximating Functions with Exponential Functions

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.

    2005-01-01

    The possibility of approximating a function with a linear combination of exponential functions of the form e[superscript x], e[superscript 2x], ... is considered as a parallel development to the notion of Taylor polynomials which approximate a function with a linear combination of power function terms. The sinusoidal functions sin "x" and cos "x"…

  11. African-American mitochondrial DNAs often match mtDNAs found in multiple African ethnic groups

    PubMed Central

    Ely, Bert; Wilson, Jamie Lee; Jackson, Fatimah; Jackson, Bruce A

    2006-01-01

    West or West Central Africa than those found in eastern or southern Africa. Fewer than 14% of the African-American mtDNA sequences matched sequences from only West Africa or only West Central Africa. Conclusion Our database of sub-Saharan mtDNA sequences includes the most common haplotypes that are shared among ethnic groups from multiple regions of Africa. These common haplotypes have been found in half of all sub-Saharan Africans. More than 60% of the remaining haplotypes differ from the common haplotypes at a single nucleotide position in the HVS-I region, and they are likely to occur at varying frequencies within sub-Saharan Africa. However, the finding that 40% of the African-American mtDNAs analyzed had no match in the database indicates that only a small fraction of the total number of African haplotypes has been identified. In addition, the finding that fewer than 10% of African-American mtDNAs matched mtDNA sequences from a single African region suggests that few African Americans might be able to trace their mtDNA lineages to a particular region of Africa, and even fewer will be able to trace their mtDNA to a single ethnic group. However, no firm conclusions should be made until a much larger database is available. It is clear, however, that when identical mtDNA haplotypes are shared among many ethnic groups from different parts of Africa, it is impossible to determine which single ethnic group was the source of a particular maternal ancestor based on the mtDNA sequence. PMID:17038170

  12. Approximate circuits for increased reliability

    DOEpatents

    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.

  13. 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.

  14. 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

  15. Coccidioidomycosis in African Americans

    PubMed Central

    Ruddy, Barbara E.; Mayer, Anita P.; Ko, Marcia G.; Labonte, Helene R.; Borovansky, Jill A.; Boroff, Erika S.; Blair, Janis E.

    2011-01-01

    Coccidioidomycosis is caused by Coccidioides species, a fungus endemic to the desert regions of the southwestern United States, and is of particular concern for African Americans. We performed a PubMed search of the English-language medical literature on coccidioidomycosis in African Americans and summarized the pertinent literature. Search terms were coccidioidomycosis, Coccidioides, race, ethnicity, African, black, and Negro. The proceedings of the national and international coccidioidomycosis symposia were searched. All relevant articles and their cited references were reviewed; those with epidemiological, immunologic, clinical, and therapeutic data pertaining to coccidioidomycosis in African Americans were included in the review. Numerous studies documented an increased predilection for severe coccidioidal infections, coccidioidomycosis-related hospitalizations, and extrapulmonary dissemination in persons of African descent; however, most of the published studies are variably problematic. The immunologic mechanism for this predilection is unclear. The clinical features and treatment recommendations are summarized. Medical practitioners need to be alert to the possibility of coccidioidomycosis in persons with recent travel to or residence in an area where the disease is endemic. PMID:21193657

  16. Approximating subtree distances between phylogenies.

    PubMed

    Bonet, Maria Luisa; St John, Katherine; Mahindru, Ruchi; Amenta, Nina

    2006-10-01

    We give a 5-approximation algorithm to the rooted Subtree-Prune-and-Regraft (rSPR) distance between two phylogenies, which was recently shown to be NP-complete. This paper presents the first approximation result for this important tree distance. The algorithm follows a standard format for tree distances. The novel ideas are in the analysis. In the analysis, the cost of the algorithm uses a "cascading" scheme that accounts for possible wrong moves. This accounting is missing from previous analysis of tree distance approximation algorithms. Further, we show how all algorithms of this type can be implemented in linear time and give experimental results.

  17. Mental Health and African Americans

    MedlinePlus

    ... Minority Population Profiles > Black/African American > Mental Health Mental Health and African Americans Poverty level affects mental health ... compared to 120% of non-Hispanic whites. 1 MENTAL HEALTH STATUS Serious psychological distress among adults 18 years ...

  18. 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

  19. 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.

  20. Dual approximations in optimal control

    NASA Technical Reports Server (NTRS)

    Hager, W. W.; Ianculescu, G. D.

    1984-01-01

    A dual approximation for the solution to an optimal control problem is analyzed. The differential equation is handled with a Lagrange multiplier while other constraints are treated explicitly. An algorithm for solving the dual problem is presented.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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…

  6. 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…

  7. Suburban migration and the birth outcome of Chicago-born white and African-American women: the merit of the healthy migrant theory?

    PubMed

    Collins, James W; Rankin, Kristin M; Janowiak, Christine M

    2013-11-01

    The healthy migrant theory posits that women who migrate before pregnancy are intrinsically healthier and therefore have better birth outcomes than those who don't move. Objective. To determine whether migration to the suburbs is associated with lower rates of preterm (<37 weeks) birth among Chicago-born White and African-American mothers. We performed stratified and multilevel logistic regression analyses on an Illinois transgenerational dataset of non-Latino White and African-American infants (1989-1991) and their mothers (1956-1976) with appended US census income information. Forty percent of Chicago-born White mothers (N = 45,135) migrated to Suburban Cook County and 30 % migrated to the more geographically distant collar counties. In contrast, 10 % of Chicago-born African-American mothers (N = 41,221) migrated to Suburban Cook and only two percent migrated to the collar counties. Chicago-born White and African-American migrant mothers to Suburban Cook County had lower preterm birth rates than their non-migrant counterparts; RR = 0.8 (0.8-0.9) and 0.8 (0.7-0.8), respectively. When neighborhood income was singularly taken into account, the protective association of suburban migration and preterm birth disappeared among Chicago-born Whites. In race-specific multilevel multivariate regression models which included neighborhood income, the adjusted odds ratio of preterm birth, low birth weight, and small for gestational-age for Chicago-born White and African-American migrant (compared to non-migrant) mothers approximated unity. Neighborhood income underlies the protective association of suburban migration and birth outcome among Chicago-born White and African-American mothers. These findings do not support the healthy migrant hypothesis of reproductive outcome.

  8. 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

  9. 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

    2011-07-20

    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.

  10. What does it take to have a positive impact on minority students' college retention?

    PubMed

    Newman, P R; Newman, B M

    1999-01-01

    This paper describes the Young Scholars Program (YSP), which seeks to expand the pool of African American and other underrepresented minority youth who aspire to attend college, and to help them meet entrance requirements and successfully obtain a college degree. Quarter-by-quarter data for the first two groups of YSP students entering The Ohio State University were promising. Their retention rates approximated university averages, while comparison groups showed lower levels of retention. It was concluded that the many facets of the Young Scholars Program, as well as the students' positive reputation among family members, peers, and teachers, produced strong motivation, ability, and determination to succeed.

  11. 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.

  12. An Origami Approximation to the Cosmic Web

    NASA Astrophysics Data System (ADS)

    Neyrinck, Mark C.

    2016-10-01

    The powerful Lagrangian view of structure formation was essentially introduced to cosmology by Zel'dovich. In the current cosmological paradigm, a dark-matter-sheet 3D manifold, inhabiting 6D position-velocity phase space, was flat (with vanishing velocity) at the big bang. Afterward, gravity stretched and bunched the sheet together in different places, forming a cosmic web when projected to the position coordinates. Here, I explain some properties of an origami approximation, in which the sheet does not stretch or contract (an assumption that is false in general), but is allowed to fold. Even without stretching, the sheet can form an idealized cosmic web, with convex polyhedral voids separated by straight walls and filaments, joined by convex polyhedral nodes. The nodes form in `polygonal' or `polyhedral' collapse, somewhat like spherical/ellipsoidal collapse, except incorporating simultaneous filament and wall formation. The origami approximation allows phase-space geometries of nodes, filaments, and walls to be more easily understood, and may aid in understanding spin correlations between nearby galaxies. This contribution explores kinematic origami-approximation models giving velocity fields for the first time.

  13. 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…

  14. African Americans and Agriculture.

    ERIC Educational Resources Information Center

    Morgan, Joan

    2000-01-01

    Reviews the opportunities available in the field of agriculture for African American students and notes efforts of the 136 colleges of agriculture to publicize their offerings and recruit students. Profiles six black leaders in agriculture, highlighting their achievements in research and aid to developing countries. A table provides data on annual…

  15. African Literature: Selected Resources.

    ERIC Educational Resources Information Center

    Deschenes, Martin O.; Waters, Harold A.

    This bibliography of resources for the teaching of African literature includes over 100 citations of books, textbooks, anthologies, plays, novels, short stories, and periodicals in French and English. Publishing house addresses, audiovisual aids, professional organizations, and a course list are also cited. The books are listed under the following…

  16. Rational approximations for tomographic reconstructions

    NASA Astrophysics Data System (ADS)

    Reynolds, Matthew; Beylkin, Gregory; Monzón, Lucas

    2013-06-01

    We use optimal rational approximations of projection data collected in x-ray tomography to improve image resolution. Under the assumption that the object of interest is described by functions with jump discontinuities, for each projection we construct its rational approximation with a small (near optimal) number of terms for a given accuracy threshold. This allows us to augment the measured data, i.e., double the number of available samples in each projection or, equivalently, extend (double) the domain of their Fourier transform. We also develop a new, fast, polar coordinate Fourier domain algorithm which uses our nonlinear approximation of projection data in a natural way. Using augmented projections of the Shepp-Logan phantom, we provide a comparison between the new algorithm and the standard filtered back-projection algorithm. We demonstrate that the reconstructed image has improved resolution without additional artifacts near sharp transitions in the image.

  17. 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.

  18. Screening for Depression in African American Churches

    PubMed Central

    Hankerson, Sidney H.; Lee, Young A; Brawley, David K.; Braswell, Kenneth; Wickramaratne, Priya J.; Weissman, Myrna M.

    2015-01-01

    Introduction Substantial racial/ethnic disparities exist in the identification and management of major depression.1 Faith-Based Health Promotion interventions reduce disparities in health screenings for numerous medical conditions.2 However, the feasibility of systematically screening for depression in faith-based settings has not been investigated. The purpose of this study was to assess the feasibility of using a validated instrument to screen for depression in African American churches. Methods Participants were recruited between October and November 2012 at three predominantly African American churches in New York City. A participatory research approach was used to determine screening days. The Patient Health Questionnaire-9 (PHQ-9) was administered to 122 participants. Positive depression screen was defined as a PHQ-9 score ≥10. Descriptive statistics were used to report sample characteristics, prevalence of participants who screened positive, and history of help seeking. Logistic regression analyses were conducted to determine the association of positive depression screen and sociodemographic characteristics. Initial analyses were conducted in 2013, with additional analyses in 2014. Results The prevalence estimate for positive depression screen was 19.7%. More men (22.5%) screened positive than women (17.7%). Total household income was inversely related to positive depression screen. A similar percentage of respondents had previously sought help from primary care providers as from clergy. Conclusions It was feasible to screen for depression with the PHQ-9 in African American churches. The prevalence of positive depression screen was high, especially among black men. Churches may be an important setting in which to identify depressive symptoms in this underserved population. PMID:26232907

  19. The Iraqization of Africa? Looking at AFRICOM from a South African Perspective

    DTIC Science & Technology

    2008-01-01

    Esterhuyse.indd 111 2/7/08 8:25:12 AM The Iraqization of Africa ? Looking at AFRICOM from a South African Perspective Abel Esterhuyse...Introduction The South African government has openly expressed its opposition towards the creation of the US Africa Command (AFRICOM).1 What’s more...South Africa presents its position on AFRICOM as representative of the country as a whole, but particularly on behalf of a group of African countries

  20. Adaptive approximation models in optimization

    SciTech Connect

    Voronin, A.N.

    1995-05-01

    The paper proposes a method for optimization of functions of several variables that substantially reduces the number of objective function evaluations compared to traditional methods. The method is based on the property of iterative refinement of approximation models of the optimand function in approximation domains that contract to the extremum point. It does not require subjective specification of the starting point, step length, or other parameters of the search procedure. The method is designed for efficient optimization of unimodal functions of several (not more than 10-15) variables and can be applied to find the global extremum of polymodal functions and also for optimization of scalarized forms of vector objective functions.

  1. Approximating spatially exclusive invasion processes

    NASA Astrophysics Data System (ADS)

    Ross, Joshua V.; Binder, Benjamin J.

    2014-05-01

    A number of biological processes, such as invasive plant species and cell migration, are composed of two key mechanisms: motility and reproduction. Due to the spatially exclusive interacting behavior of these processes a cellular automata (CA) model is specified to simulate a one-dimensional invasion process. Three (independence, Poisson, and 2D-Markov chain) approximations are considered that attempt to capture the average behavior of the CA. We show that our 2D-Markov chain approximation accurately predicts the state of the CA for a wide range of motility and reproduction rates.

  2. Heat pipe transient response approximation.

    SciTech Connect

    Reid, R. S.

    2001-01-01

    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.

  3. Second Approximation to Conical Flows

    DTIC Science & Technology

    1950-12-01

    Public Release WRIGHT AIR DEVELOPMENT CENTER AF-WP-(B)-O-29 JUL 53 100 NOTICES ’When Government drawings, specifications, or other data are used V...so that the X, the approximation always depends on the ( "/)th, etc. Here the second approximation, i.e., the terms in C and 62, are computed and...the scheme shown in Fig. 1, the isentropic equations of motion are (cV-X2) +~X~C 6 +- 4= -x- 1 It is assumed that + Ux !E . $O’/ + (8) Introducing Eqs

  4. Mothers' parenting and child sex differences in behavior problems among African American preschoolers.

    PubMed

    Barnett, Melissa A; Scaramella, Laura V

    2013-10-01

    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. In this study, we examined 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 consisted of 137 African American low-income families with one sibling approximately 2 years old and the closest-aged older sibling who was approximately 4 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, whereas 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.

  5. 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

  6. 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…

  7. 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…

  8. Intrinsic unsharpness and approximate repeatability of quantum measurements

    NASA Astrophysics Data System (ADS)

    Carmeli, Claudio; Heinonen, Teiko; Toigo, Alessandro

    2007-02-01

    The intrinsic unsharpness of a quantum observable is studied by introducing the notion of resolution width. This quantification of accuracy is shown to be closely connected with the possibility of making approximately repeatable measurements. As a case study, the intrinsic unsharpness and approximate repeatability of position and momentum measurements are examined in detail.

  9. Effective screening for Alzheimer's disease among older African Americans.

    PubMed

    Mast, B T; Fitzgerald, J; Steinberg, J; MacNeill, S E; Lichtenberg, P A

    2001-05-01

    Relatively little data exist concerning the utility of brief cognitive measures to detect dementia among African Americans. The current study evaluated the clinical utility of the Mini-Mental Status Exam (MMSE) and the Fuld Object Memory Evaluation (FOME) in detecting Alzheimer's disease (AD) among both African American and European American older adults. One hundred and forty geriatric patients from a large urban academic medical center were examined. Overall, the FOME appeared to be more effective in detecting AD than was the MMSE (93% sensitivity vs. 75% sensitivity, respectively), although both measures suffered from relatively low specificity (63.5) in the full sample. The FOME demonstrated exceptional clinical utility among African American patients (sensitivity 98.3%; specificity = 64.5; positive predictive power 83.8%; negative predictive power 95.2%). The results of this study support the use of the FOME among older African Americans to detect dementia.

  10. Transgenerational Consequences of Racial Discrimination for African American Health

    PubMed Central

    Goosby, Bridget J.; Heidbrink, Chelsea

    2014-01-01

    Disparities in African American health remain pervasive and persist transgenerationally. There is a growing consensus that both structural and interpersonal racial discrimination are key mechanisms affecting African American health. The Biopsychosocial Model of Racism as a Stressor posits that the persistent stress of experiencing discrimination take a physical toll on the health of African Americans and is ultimately manifested in the onset of illness. However, the degree to which the health consequences of racism and discrimination can be passed down from one generation to the next is an important avenue of exploration. In this review, we discuss and link literature across disciplines demonstrating the harmful impact of racism on African American physical health and the health of their offspring. PMID:24855488

  11. 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.

  12. A decade of experience with renal transplantation in African-Americans.

    PubMed

    Foster, Clarence E; Philosophe, Benjamin; Schweitzer, Eugene J; Colonna, John O; Farney, Alan C; Jarrell, Bruce; Anderson, Leslie; Bartlett, Stephen T

    2002-12-01

    OBJECTIVE To evaluate the strategies instituted by the authors' center to decrease the time to transplantation and increase the rate of transplantation for African-Americans, consisting of a formal education program concerning the benefits of living organ donation that is oriented to minorities; a laparoscopic living donation program; use of hepatitis C-positive donors in documented positive recipients; and encouraging vaccination for hepatitis B, allowing the use of hepatitis B core Ab-positive donors. SUMMARY BACKGROUND DATA The national shortage of suitable kidney donor organs has disproportional and adverse effects on African-Americans for several reasons. Type II diabetes mellitus and hypertension, major etiologic factors for end-stage renal disease, are more prevalent in African-Americans than in the general population. Once kidney failure has developed, African-Americans are disadvantaged for the following reasons: this patient cohort has longer median waiting times on the renal transplant list; African-Americans have higher rates of acute rejection, which affects long-term allograft survival; and once they are transplanted, the long-term graft survival rates are lower in this population than in other groups. METHODS From March 1990 to November 2001 the authors' center performed 2,167 renal transplants; 944 were in African-Americans (663 primary cadaver renal transplants and 253 primary Living donor renal transplants). The retransplants consisted of 83 cadaver transplants and 17 living donor transplants. Outcome measures of this retrospective analysis included median waiting time, graft and patient survival rates, and the rate of living donation in African-Americans and comparable non-African-Americans. Where applicable, data are compared to United Network for Organ Sharing national statistics. Statistical analysis employed appropriate SPSS applications. RESULTS One- and 5-year patient survival rates for living donor kidneys were 97.1% and 91.3% for non-African

  13. 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.

  14. Ab initio dynamical vertex approximation

    NASA Astrophysics Data System (ADS)

    Galler, Anna; Thunström, Patrik; Gunacker, Patrik; Tomczak, Jan M.; Held, Karsten

    2017-03-01

    Diagrammatic extensions of dynamical mean-field theory (DMFT) such as the dynamical vertex approximation (DΓ A) allow us to include nonlocal correlations beyond DMFT on all length scales and proved their worth for model calculations. Here, we develop and implement an Ab initio DΓ A approach (AbinitioDΓ A ) for electronic structure calculations of materials. The starting point is the two-particle irreducible vertex in the two particle-hole channels which is approximated by the bare nonlocal Coulomb interaction and all local vertex corrections. From this, we calculate the full nonlocal vertex and the nonlocal self-energy through the Bethe-Salpeter equation. The AbinitioDΓ A approach naturally generates all local DMFT correlations and all nonlocal G W contributions, but also further nonlocal correlations beyond: mixed terms of the former two and nonlocal spin fluctuations. We apply this new methodology to the prototypical correlated metal SrVO3.

  15. Potential of the approximation method

    SciTech Connect

    Amano, K.; Maruoka, A.

    1996-12-31

    Developing some techniques for the approximation method, we establish precise versions of the following statements concerning lower bounds for circuits that detect cliques of size s in a graph with m vertices: For 5 {le} s {le} m/4, a monotone circuit computing CLIQUE(m, s) contains at least (1/2)1.8{sup min}({radical}s-1/2,m/(4s)) gates: If a non-monotone circuit computes CLIQUE using a {open_quotes}small{close_quotes} amount of negation, then the circuit contains an exponential number of gates. The former is proved very simply using so called bottleneck counting argument within the framework of approximation, whereas the latter is verified introducing a notion of restricting negation and generalizing the sunflower contraction.

  16. Nonlinear Filtering and Approximation Techniques

    DTIC Science & Technology

    1991-09-01

    Shwartz), Academic Press (1991). [191 M.Cl. ROUTBAUD, Fiting lindairc par morceaux avec petit bruit d’obserration, These. Universit6 de Provence ( 1990...Kernel System (GKS), Academic Press (1983). 181 H.J. KUSHNER, Probability methods for approximations in stochastic control and for elliptic equations... Academic Press (1977). [9] F. LE GLAND, Time discretization of nonlinear filtering equations, in: 28th. IEEE CDC, Tampa, pp. 2601-2606. IEEE Press (1989

  17. Reliable Function Approximation and Estimation

    DTIC Science & Technology

    2016-08-16

    Journal on Mathematical Analysis 47 (6), 2015. 4606-4629. (P3) The Sample Complexity of Weighted Sparse Approximation. B. Bah and R. Ward. IEEE...solving systems of quadratic equations. S. Sanghavi, C. White, and R. Ward. Results in Mathematics , 2016. (O5) Relax, no need to round: Integrality of...Theoretical Computer Science. (O6) A unified framework for linear dimensionality reduction in L1. F Krahmer and R Ward. Results in Mathematics , 2014. 1-23

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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…

  4. 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…

  5. African American Women and Brown: A Lingering Twilight or Emerging Dawn?

    ERIC Educational Resources Information Center

    Lindsay, Beverly

    1994-01-01

    Critically examines the factors continuing to impede the integral presence of African American women in pivotal decision-making positions in colleges and universities. Interviews with three African American women who were among the first deans or associate deans of education at leading schools are presented, detailing their experiences and views…

  6. 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…

  7. 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…

  8. 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…

  9. 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…

  10. African American families' expectations and intentions for mental health services.

    PubMed

    Thompson, Richard; Dancy, Barbara L; Wiley, Tisha R A; Najdowski, Cynthia J; Perry, Sylvia P; Wallis, Jason; Mekawi, Yara; Knafl, Kathleen A

    2013-09-01

    A cross-sectional qualitative descriptive design was used to examine the links among expectations about, experiences with, and intentions toward mental health services. Individual face-to-face interviews were conducted with a purposive sample of 32 African American youth/mothers dyads. Content analysis revealed that positive expectations were linked to positive experiences and intentions, that negative expectations were not consistently linked to negative experiences or intentions, nor were ambivalent expectations linked to ambivalent experiences or intentions. Youth were concerned about privacy breeches and mothers about the harmfulness of psychotropic medication. Addressing these concerns may promote African Americans' engagement in mental health services.

  11. African American Families’ Expectations and Intentions for Mental Health Services

    PubMed Central

    Thompson, Richard; Dancy, Barbara L.; Wiley, Tisha R.A.; Najdowski, Cynthia J.; Perry, Sylvia P.; Wallis, Jason; Mekawi, Yara; Knafl, Kathleen

    2012-01-01

    A cross-sectional qualitative descriptive design was used to examine the links among expectations about, experiences with, and intentions toward mental health services. Individual face-to-face interviews were conducted with a purposive sample of 32 African American youth/mothers dyads. Content analysis revealed that positive expectations were linked to positive experiences and intentions, that negative expectations were not consistently linked to negative experiences or intentions, nor were ambivalent expectations linked to ambivalent experiences or intentions. Youth were concerned about privacy breeches and mothers about the harmfulness of psychotropic medication. Addressing these concerns may promote African Americans’ engagement in mental health services. PMID:22791083

  12. Media and cultural influences in african-american girls' eating disorder risk.

    PubMed

    Jones, Lakaii A; Cook-Cottone, Catherine

    2013-01-01

    Objective. To investigate media and cultural influences in eating disorder development in African-American adolescent females. Method. Fifty-seven participants were recruited through churches and community organizations to complete a questionnaire. Results. Mainstream sociocultural identification was associated with more eating disorder behavior in African-American females; cultural ethnic identification was not significantly associated with eating disorder behavior in African-American females, mainstream sociocultural identification, cultural ethnic identification, and body dissatisfaction significantly predicted eating disorder behavior; and cultural ethnic identification was positively correlated with mainstream sociocultural identification. This study provides support for the importance of eating disorder prevention interventions that focus specifically on African-American girls.

  13. Media and Cultural Influences in African-American Girls' Eating Disorder Risk

    PubMed Central

    Jones, Lakaii A.; Cook-Cottone, Catherine

    2013-01-01

    Objective. To investigate media and cultural influences in eating disorder development in African-American adolescent females. Method. Fifty-seven participants were recruited through churches and community organizations to complete a questionnaire. Results. Mainstream sociocultural identification was associated with more eating disorder behavior in African-American females; cultural ethnic identification was not significantly associated with eating disorder behavior in African-American females, mainstream sociocultural identification, cultural ethnic identification, and body dissatisfaction significantly predicted eating disorder behavior; and cultural ethnic identification was positively correlated with mainstream sociocultural identification. This study provides support for the importance of eating disorder prevention interventions that focus specifically on African-American girls. PMID:24967141

  14. Diversity among African Pygmies

    PubMed Central

    Ramírez Rozzi, Fernando V.; Sardi, Marina L.

    2010-01-01

    Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D) landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies) were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression) and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies. PMID:21049030

  15. Human African trypanosomiasis.

    PubMed

    Lejon, Veerle; Bentivoglio, Marina; Franco, José Ramon

    2013-01-01

    Human African trypanosomiasis or sleeping sickness is a neglected tropical disease that affects populations in sub-Saharan Africa. The disease is caused by infection with the gambiense and rhodesiense subspecies of the extracellular parasite Trypanosoma brucei, and is transmitted to humans by bites of infected tsetse flies. The disease evolves in two stages, the hemolymphatic and meningoencephalitic stages, the latter being defined by central nervous system infection after trypanosomal traversal of the blood-brain barrier. African trypanosomiasis, which leads to severe neuroinflammation, is fatal without treatment, but the available drugs are toxic and complicated to administer. The choice of medication is determined by the infecting parasite subspecies and disease stage. Clinical features include a constellation of nonspecific symptoms and signs with evolving neurological and psychiatric alterations and characteristic sleep-wake disturbances. Because of the clinical profile variability and insidiously progressive central nervous system involvement, disease staging is currently based on cerebrospinal fluid examination, which is usually performed after the finding of trypanosomes in blood or other body fluids. No vaccine being available, control of human African trypanosomiasis relies on diagnosis and treatment of infected patients, assisted by vector control. Better diagnostic tools and safer, easy to use drugs are needed to facilitate elimination of the disease.

  16. On polyhedral approximations in an n-dimensional space

    NASA Astrophysics Data System (ADS)

    Balashov, M. V.

    2016-10-01

    The polyhedral approximation of a positively homogeneous (and, in general, nonconvex) function on a unit sphere is investigated. Such a function is presupporting (i.e., its convex hull is the supporting function) for a convex compact subset of R n . The considered polyhedral approximation of this function provides a polyhedral approximation of this convex compact set. The best possible estimate for the error of the considered approximation is obtained in terms of the modulus of uniform continuous subdifferentiability in the class of a priori grids of given step in the Hausdorff metric.

  17. 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.

  18. 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

  19. Fermion tunneling beyond semiclassical approximation

    SciTech Connect

    Majhi, Bibhas Ranjan

    2009-02-15

    Applying the Hamilton-Jacobi method beyond the semiclassical approximation prescribed in R. Banerjee and B. R. Majhi, J. High Energy Phys. 06 (2008) 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.

  20. 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.

  1. 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.}

  2. Approximate transferability in conjugated polyalkenes

    NASA Astrophysics Data System (ADS)

    Eskandari, Keiamars; Mandado, Marcos; Mosquera, Ricardo A.

    2007-03-01

    QTAIM computed atomic and bond properties, as well as delocalization indices (obtained from electron densities computed at HF, MP2 and B3LYP levels) of several linear and branched conjugated polyalkenes and O- and N-containing conjugated polyenes have been employed to assess approximate transferable CH groups. The values of these properties indicate the effects of the functional group extend to four CH groups, whereas those of the terminal carbon affect up to three carbons. Ternary carbons also modify significantly the properties of atoms in α, β and γ.

  3. Finite difference methods for approximating Heaviside functions

    NASA Astrophysics Data System (ADS)

    Towers, John D.

    2009-05-01

    We present a finite difference method for discretizing a Heaviside function H(u(x→)), where u is a level set function u:Rn ↦ R that is positive on a bounded region Ω⊂Rn. There are two variants of our algorithm, both of which are adapted from finite difference methods that we proposed for discretizing delta functions in [J.D. Towers, Two methods for discretizing a delta function supported on a level set, J. Comput. Phys. 220 (2007) 915-931; J.D. Towers, Discretizing delta functions via finite differences and gradient normalization, Preprint at http://www.miracosta.edu/home/jtowers/; J.D. Towers, A convergence rate theorem for finite difference approximations to delta functions, J. Comput. Phys. 227 (2008) 6591-6597]. We consider our approximate Heaviside functions as they are used to approximate integrals over Ω. We prove that our first approximate Heaviside function leads to second order accurate quadrature algorithms. Numerical experiments verify this second order accuracy. For our second algorithm, numerical experiments indicate at least third order accuracy if the integrand f and ∂Ω are sufficiently smooth. Numerical experiments also indicate that our approximations are effective when used to discretize certain singular source terms in partial differential equations. We mostly focus on smooth f and u. By this we mean that f is smooth in a neighborhood of Ω, u is smooth in a neighborhood of ∂Ω, and the level set u(x)=0 is a manifold of codimension one. However, our algorithms still give reasonable results if either f or u has jumps in its derivatives. Numerical experiments indicate approximately second order accuracy for both algorithms if the regularity of the data is reduced in this way, assuming that the level set u(x)=0 is a manifold. Numerical experiments indicate that dependence on the placement of Ω with respect to the grid is quite small for our algorithms. Specifically, a grid shift results in an O(hp) change in the computed solution

  4. 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

  5. Advancing Breast Cancer Survivorship among African American Women

    PubMed Central

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

    2015-01-01

    Purpose Advances have occurred in breast cancer survivorship but, for many African American women, challenges and gaps in relevant information remain. Methods 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. Results 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. Conclusions 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

  6. African American leadership groups: smoking with the enemy

    PubMed Central

    Yerger, V; Malone, R

    2002-01-01

    Background: Among all racial and ethnic groups in the USA, African Americans bear the greatest burden from tobacco related disease. The tobacco industry has been highly influential in the African American community for decades, providing funding and other resources to community leaders and emphasising publicly its support for civil rights causes and groups, while ignoring the negative health effects of its products on those it claims to support. However, the industry's private business reasons for providing such support were unknown. Objective: To understand how and for what purposes the tobacco industry sought to establish and maintain relationships with African American leaders. Methods: Review and analysis of over 700 previously secret internal tobacco industry documents available on the internet. Results: The tobacco industry established relationships with virtually every African American leadership organisation and built longstanding social connections with the community, for three specific business reasons: to increase African American tobacco use, to use African Americans as a frontline force to defend industry policy positions, and to defuse tobacco control efforts. Conclusion: As the tobacco industry expands its global reach, public health advocates should anticipate similar industry efforts to exploit the vulnerabilities of marginalised groups. The apparent generosity, inclusion, and friendship proffered by the industry extract a price from groups in the health of their members. Helping groups anticipate such efforts, confront industry co-optation, and understand the hidden costs of accepting tobacco industry largesse should be part of worldwide tobacco control efforts. PMID:12432159

  7. 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.

  8. Laguerre approximation of random foams

    NASA Astrophysics Data System (ADS)

    Liebscher, André

    2015-09-01

    Stochastic models for the microstructure of foams are valuable tools to study the relations between microstructure characteristics and macroscopic properties. Owing to the physical laws behind the formation of foams, Laguerre tessellations have turned out to be suitable models for foams. Laguerre tessellations are weighted generalizations of Voronoi tessellations, where polyhedral cells are formed through the interaction of weighted generator points. While both share the same topology, the cell curvature of foams allows only an approximation by Laguerre tessellations. This makes the model fitting a challenging task, especially when the preservation of the local topology is required. In this work, we propose an inversion-based approach to fit a Laguerre tessellation model to a foam. The idea is to find a set of generator points whose tessellation best fits the foam's cell system. For this purpose, we transform the model fitting into a minimization problem that can be solved by gradient descent-based optimization. The proposed algorithm restores the generators of a tessellation if it is known to be Laguerre. If, as in the case of foams, no exact solution is possible, an approximative solution is obtained that maintains the local topology.

  9. A Review of Genetics, Arterial Stiffness, and Blood Pressure in African Americans

    PubMed Central

    Hall, Jennifer L.; Duprez, Daniel A.; Barac, Ana; Rich, Stephen S.

    2012-01-01

    The prevalence of hypertension in African Americans in the United States is amongst the highest in the world and increasing. The identification of genes and pathways regulating blood pressure in African Americans has been challenging. An early predictor of hypertension is arterial stiffness. The prevalence of arterial stiffness is significantly higher in African Americans compared to Caucasians. Approximately 20% of the variance in arterial stiffness is estimated to be heritable. Identifying genes and biological pathways regulating arterial stiffness may provide insight into the genetics underlying the increased risk of hypertension in African Americans. This paper reviews the genetic findings to date in the area of arterial stiffness and blood pressure in African Americans with an emphasis on the current limitations and new efforts to move the field forward. PMID:22492025

  10. Analytical approximations for spiral waves

    SciTech Connect

    Löber, Jakob Engel, Harald

    2013-12-15

    We propose a non-perturbative attempt to solve the kinematic equations for spiral waves in excitable media. From the eikonal equation for the wave front we derive an implicit analytical relation between rotation frequency Ω and core radius R{sub 0}. For free, rigidly rotating spiral waves our analytical prediction is in good agreement with numerical solutions of the linear eikonal equation not only for very large but also for intermediate and small values of the core radius. An equivalent Ω(R{sub +}) dependence improves the result by Keener and Tyson for spiral waves pinned to a circular defect of radius R{sub +} with Neumann boundaries at the periphery. Simultaneously, analytical approximations for the shape of free and pinned spirals are given. We discuss the reasons why the ansatz fails to correctly describe the dependence of the rotation frequency on the excitability of the medium.

  11. 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.

  12. Analytical approximations for spiral waves.

    PubMed

    Löber, Jakob; Engel, Harald

    2013-12-01

    We propose a non-perturbative attempt to solve the kinematic equations for spiral waves in excitable media. From the eikonal equation for the wave front we derive an implicit analytical relation between rotation frequency Ω and core radius R(0). For free, rigidly rotating spiral waves our analytical prediction is in good agreement with numerical solutions of the linear eikonal equation not only for very large but also for intermediate and small values of the core radius. An equivalent Ω(R(+)) dependence improves the result by Keener and Tyson for spiral waves pinned to a circular defect of radius R(+) with Neumann boundaries at the periphery. Simultaneously, analytical approximations for the shape of free and pinned spirals are given. We discuss the reasons why the ansatz fails to correctly describe the dependence of the rotation frequency on the excitability of the medium.

  13. Indexing the approximate number system.

    PubMed

    Inglis, Matthew; Gilmore, Camilla

    2014-01-01

    Much recent research attention has focused on understanding individual differences in the approximate number system, a cognitive system believed to underlie human mathematical competence. To date researchers have used four main indices of ANS acuity, and have typically assumed that they measure similar properties. Here we report a study which questions this assumption. We demonstrate that the numerical ratio effect has poor test-retest reliability and that it does not relate to either Weber fractions or accuracy on nonsymbolic comparison tasks. Furthermore, we show that Weber fractions follow a strongly skewed distribution and that they have lower test-retest reliability than a simple accuracy measure. We conclude by arguing that in the future researchers interested in indexing individual differences in ANS acuity should use accuracy figures, not Weber fractions or numerical ratio effects.

  14. Genetic epidemiology of hypertension: an update on the African diaspora.

    PubMed

    Daniel, Harold I; Rotimi, Charles N

    2003-01-01

    Hypertension is a serious global public health problem, affecting approximately 600 million people worldwide. The lifetime risk of developing the condition exceeds 50% in most populations. Despite considerable success in the pharmacological treatment of hypertension in all-human populations, the health-care community still lacks understanding of how and why individuals develop chronically elevated blood pressure. This gap in knowledge, and the high prevalence of hypertension and associated complications in some populations of African descent, have led some to conclude that hypertension is a "different disease" in people of African descent. Despite considerable evidence from epidemiologic studies showing that blood pressure distribution in populations of the African diaspora spans the known spectrum for all human populations, theories in support of unique "defects" among populations of African descent continue to gain wide acceptance. To date, no known environmental factors or genetic variants relevant to the pathophysiology of human hypertension have been found to be unique to Black populations. However, available genetic epidemiologic data demonstrate differential distributions of risk factors that are consistent with current environmental and geographic origins. This review summarizes the available evidence and demonstrates that as the exposure to known risk factors for hypertension (eg, excess consumption of salt and calories, stress, sedentary lifestyle, and degree of urbanization) increases among genetically susceptible individuals, the prevalence of hypertension and associated complications also increases across populations of the African diaspora. This observation is true for all human populations.

  15. 'We are doing our best': African and African-Caribbean fatherhood, health and preventive primary care services, in England.

    PubMed

    Williams, Robert; Hewison, Alistair; Stewart, Mel; Liles, Clive; Wildman, Stuart

    2012-03-01

    Recent policy pronouncements emphasise the importance of engaging fathers with preventive primary care services. However, in England, there is a paucity of literature which examines African and African-Caribbean fathers' experiences of service provision. This paper reports a study that investigated African and African-Caribbean fathers' beliefs about fatherhood, health and preventive primary care services, with the aim of addressing the deficit in the literature. Nine focus groups involving 46 African and African-Caribbean fathers, recruited using purposive sampling, were undertaken between October 2008-January 2009. Fatherhood was seen as a core aspect of the participants' identities. The fathers enacted these identities in a number of ways, such as caring for and protecting children, which were influenced by spirituality, relationships with women, paid work and racism. The fathers had concerns about their bodies, medical conditions, physical activity and forms of consumption. However, their primary focus was on maintaining and improving the well-being of their children. This resulted in them neglecting their own health needs as they had to meet the obligations of family life and paid work. The fathers reported limited contact with preventive primary care services and were unaware of their purpose, function and availability. They identified ethnicity as a positive asset, and felt their families and communities had particular strengths. However they acknowledged that structural constraints, including racism, influenced their perceptions of and access to local health services. The engagement of African and African-Caribbean fathers needs to be addressed more specifically in policy as part of a broader programme of action to tackle health inequalities. In addition, child health services could build on fathers' commitment to children's well-being through practice that addresses fathers' as well as mothers' needs in families.

  16. 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.

  17. Elder Abuse among African Americans

    ERIC Educational Resources Information Center

    Tauriac, Jesse J.; Scruggs, Natoschia

    2006-01-01

    Perceptions of extreme, moderate, and mild forms of elder abuse among African-American women (n=25) and men (n=10) were examined. African-American respondents emphasized physical abuse when giving examples of extremely abusive behavior. Along with physical abuse, verbal abuse was the most frequently identified form of abuse, and was significantly…

  18. African ethics and voluntary euthanasia.

    PubMed

    Omonzejele, P F

    2004-01-01

    This paper outlines the relationship between euthanasia and its ethical norms and practices in a part of West Africa. The various sub-types of euthanasia are described in detail, parallel with the role of African ethical theories in determining their relevance. The author discusses the implications of this approach relative to the social and economic state of African communities.

  19. African-Americans and Alcoholism.

    ERIC Educational Resources Information Center

    Sigmon, Scott B.

    To better serve people in a counseling relationship, it is useful to understand them not only culturally, but demographically as well. This paper traces historical, religious, demographic aspects and treatment of alcohol abuse in African Americans. Historically, alcohol abuse and alcohol dependence have varied for African Americans. During the…

  20. Africanization in the United States

    PubMed Central

    Pinto, M. Alice; Rubink, William L.; Patton, John C.; Coulson, Robert N.; Johnston, J. Spencer

    2005-01-01

    The expansion of Africanized honeybees from South America to the southwestern United States in <50 years is considered one of the most spectacular biological invasions yet documented. In the American tropics, it has been shown that during their expansion Africanized honeybees have low levels of introgressed alleles from resident European populations. In the United States, it has been speculated, but not shown, that Africanized honeybees would hybridize extensively with European honeybees. Here we report a continuous 11-year study investigating temporal changes in the genetic structure of a feral population from the southern United States undergoing Africanization. Our microsatellite data showed that (1) the process of Africanization involved both maternal and paternal bidirectional gene flow between European and Africanized honeybees and (2) the panmitic European population was replaced by panmitic mixtures of A. m. scutellata and European genes within 5 years after Africanization. The post-Africanization gene pool (1998–2001) was composed of a diverse array of recombinant classes with a substantial European genetic contribution (mean 25–37%). Therefore, the resulting feral honeybee population of south Texas was best viewed as a hybrid swarm. PMID:15937139

  1. Interannual modulation of East African early short rains by the winter Arctic Oscillation

    NASA Astrophysics Data System (ADS)

    Gong, Dao-Yi; Guo, Dong; Mao, Rui; Yang, Jing; Gao, Yongqi; Kim, Seong-Joong

    2016-08-01

    In the present study, we analyzed the interannual linkage between the boreal winter Arctic Oscillation (AO) and East African early short rains. When the Indian Ocean Dipole and El Niño-Southern Oscillation variance are excluded by linear regression, the boreal winter AO index is significantly correlated with the October East African precipitation over the domain of 5°N-5°S and 35°-45°E for the period 1979-2014, r =+ 0.46. The upper ocean heat content likely acts as a medium that links the AO and East African precipitation. Significant subsurface warming and positive upper ocean heat content anomalies occur over the western Indian Ocean during the autumn following positive AO winters, which enriches the atmospheric moisture, intensifies convection, and enhances precipitation. Oceanic dynamics play a key role in causing this subsurface warming. Winter AO-related atmospheric circulation creates anomalous wind stress, which forces a downwelling oceanic Rossby wave between 60°-75°E and 5°-10°S, where the thermocline significantly deepens. This Rossby wave propagates westward and accompanies significant subsurface warming along the thermocline. The Rossby wave arrives at the western Indian Ocean in the late summer, significantly warming the region to the west of 55°E at a depth of 60-100 m. This warming remains significant through October. Correspondingly, the upper ocean heat content significantly increases by approximately 2-3 × 108 J m-2 in the region west of 60°E between 5° and 10°S. The role of these oceanic dynamics in linking the winter AO, and anomalous subsurface warming was tested by numerical experiments with an oceanic general circulation model. The experiments were performed with the forcing of AO-related wind stress anomalies over the Indian Ocean in the winter. The oceanic Rossby wave generated in the central Indian Ocean during boreal winter, the consequent subsurface warming, and the anomalous upper ocean heat content in October over the

  2. Cancer statistics for African Americans.

    PubMed

    Ghafoor, Asma; Jemal, Ahmedin; Cokkinides, Vilma; Cardinez, Cheryll; Murray, Taylor; Samuels, Alicia; Thun, Michael J

    2002-01-01

    The American Cancer Society provides estimates on the number of new cancer cases and deaths, and compiles health statistics on African Americans in a biennial publication, Cancer Facts and Figures for African Americans. The compiled statistics include cancer incidence, mortality, survival, and lifestyle behaviors using the most recent data on incidence and survival from the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results (SEER) program, mortality data from the National Center for Health Statistics (NCHS), and behavioral information from the Behavior Risk Factor Surveillance System (BRFSS), Youth Risk Behavior Surveillance System (YRBSS), and National Health Interview Survey (NHIS). It is estimated that 132,700 new cases of cancer and 63,100 deaths will occur among African Americans in the year 2003. Although African Americans have experienced higher incidence and mortality rates of cancer than whites for many years, incidence rates have declined by 2.7 percent per year in African-American males since 1992, while stabilizing in African-American females. During the same period, death rates declined by 2.1 percent and 0.4 percent per year among African-American males and females, respectively. The decrease in both incidence and death rates from cancer among African-American males was the largest of any racial or ethnic group. Nonetheless, African Americans still carry the highest cancer burden among US racial and ethnic groups. Most cancers detectable by screening are diagnosed at a later stage and survival rates are lower within each stage of disease in African Americans than in whites. The extent to which these disparities reflect unequal access to health care versus other factors is an active area of research.

  3. 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)

  4. "Coolin": The Psychosocial Communication of African and Latino Men.

    ERIC Educational Resources Information Center

    De La Cancela, Victor

    1993-01-01

    Explores the relationship between Latino "machismo" and the "cool pose" of the African-American male. It is suggested that both masculine postures can be used to design empowering psychological interventions in clinical, community, educational, and policy areas. Positive features could be used in curricula of diversity. (SLD)

  5. An Analysis of Bloomington's African-American Community through Photographs.

    ERIC Educational Resources Information Center

    Anderson, Dorothea

    Reproductions of 19 photographs that document some of the families and history of the African-American community in Bloomington, Indiana, from about 1870 to 1920, are contained in this paper. The paper discusses the use of photographs in historical inquiry, and posits that the photographic image carries the power of witness to past peoples and…

  6. 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…

  7. 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…

  8. Democratisation and Quality Assurance in South African Higher Education

    ERIC Educational Resources Information Center

    Symes, Ashley

    2006-01-01

    The article interprets a particular set of debates on whether quality assurance in South African higher education widens democracy or not. The interpretation explores the extent to which higher education quality assurance fulfils three conditions posited for democracy (inclusion, participation and enhancement), drawing in as points of reference…

  9. 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…

  10. 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…

  11. East African ROAD

    NASA Astrophysics Data System (ADS)

    Tekle, Kelali

    2016-10-01

    In the developing world astronomy had been treated as the science of elites. As a result of this overwhelming perception, astronomy compared with other applied sciences has got less attention and its role in development has been insignificant. However, the IAU General Assembly decision in 2009 opened new opportunity for countries and professionals to deeply look into Astronomy and its role in development. Then, the subsequent establishment of regional offices in the developing world is helping countries to integrate astronomy with other earth and space based sciences so as to progressively promote its scientific and development importance. Gradually nations have come to know that space is the frontier of tomorrow and the urgency of preeminence on space frontier starts at primary school and ascends to tertiary education. For this to happen, member nations in east African region have placed STEM education at the center of their education system. For instance, Ethiopian has changed University enrollment strategy to be in favor of science and engineering subjects, i.e. every year seventy percent of new University entrants join science and engineering fields while thirty percent social science and humanities. Such bold actions truly promote astronomy to be conceived as gateway to science and technology. To promote the concept of astronomy for development the East African regional office has actually aligned it activities to be in line with the focus areas identified by the IAU strategy (2010 to 2020).

  12. 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.

  13. An approximate projection method for incompressible flow

    NASA Astrophysics Data System (ADS)

    Stevens, David E.; Chan, Stevens T.; Gresho, Phil

    2002-12-01

    This paper presents an approximate projection method for incompressible flows. This method is derived from Galerkin orthogonality conditions using equal-order piecewise linear elements for both velocity and pressure, hereafter Q1Q1. By combining an approximate projection for the velocities with a variational discretization of the continuum pressure Poisson equation, one eliminates the need to filter either the velocity or pressure fields as is often needed with equal-order element formulations. This variational approach extends to multiple types of elements; examples and results for triangular and quadrilateral elements are provided. This method is related to the method of Almgren et al. (SIAM J. Sci. Comput. 2000; 22: 1139-1159) and the PISO method of Issa (J. Comput. Phys. 1985; 62: 40-65). These methods use a combination of two elliptic solves, one to reduce the divergence of the velocities and another to approximate the pressure Poisson equation. Both Q1Q1 and the method of Almgren et al. solve the second Poisson equation with a weak error tolerance to achieve more computational efficiency.A Fourier analysis of Q1Q1 shows that a consistent mass matrix has a positive effect on both accuracy and mass conservation. A numerical comparison with the widely used Q1Q0 (piecewise linear velocities, piecewise constant pressures) on a periodic test case with an analytic solution verifies this analysis. Q1Q1 is shown to have comparable accuracy as Q1Q0 and good agreement with experiment for flow over an isolated cubic obstacle and dispersion of a point source in its wake.

  14. The magnitude, timing and abruptness of changes in North African dust deposition over the last 20,000 years: Insights into regional atmospheric circulation and dust-related climate impacts

    NASA Astrophysics Data System (ADS)

    McGee, D.; deMenocal, P. B.; Winckler, G.; Stuut, J. W.; Bradtmiller, L. I.; Mahowald, N. M.; Albani, S.

    2012-12-01

    Reconstructions of eolian dust accumulation in West African margin sediments provide important continuous records of past changes in atmospheric circulation and aridity in the region. Existing records indicate dramatic changes in West African dust emissions over the last 20 ka, including high dust emissions during Heinrich Stadial 1 and the Younger Dryas and lower dust emissions during the African Humid Period, a period of enhanced monsoon precipitation from approximately 11.7-5 ka. The limited spatial extent of these records, as well as the lack of high-resolution flux data, do not allow us to determine whether changes in dust deposition occurred with similar timing, magnitude and abruptness throughout northwest Africa. Here we present new records from a meridional transect of cores stretching from 27°N to 19°N along the northwest African margin, as well as from cores in the western tropical Atlantic reflecting downwind deposition. By combining grain size endmember modeling with 230Th-normalized fluxes in these cores, we are able to document spatial and temporal changes in dust loads and grain size distributions within the North African dust plume throughout the last 20 ka. Our results provide quantitative estimates of the magnitude of dust flux changes associated with Heinrich Stadial 1, the Younger Dryas, and the AHP. Our data are consistent with abrupt, synchronous changes in dust fluxes in all cores at the beginning and end of the AHP. Using these new records to tune dust loadings in a fully coupled model of 6 ka climate, we find that low dust fluxes during the AHP may have had a substantial positive feedback on regional precipitation by amplifying the northward displacement of the Atlantic and West African ITCZ.

  15. 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.

  16. Uncertainty relations and approximate quantum error correction

    NASA Astrophysics Data System (ADS)

    Renes, Joseph M.

    2016-09-01

    The uncertainty principle can be understood as constraining the probability of winning a game in which Alice measures one of two conjugate observables, such as position or momentum, on a system provided by Bob, and he is to guess the outcome. Two variants are possible: either Alice tells Bob which observable she measured, or he has to furnish guesses for both cases. Here I derive uncertainty relations for both, formulated directly in terms of Bob's guessing probabilities. For the former these relate to the entanglement that can be recovered by action on Bob's system alone. This gives an explicit quantum circuit for approximate quantum error correction using the guessing measurements for "amplitude" and "phase" information, implicitly used in the recent construction of efficient quantum polar codes. I also find a relation on the guessing probabilities for the latter game, which has application to wave-particle duality relations.

  17. 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) .

  18. "I Do But I Don't": The Search for Identity in Urban African American Adolescents.

    PubMed

    Gullan, Rebecca Lakin; Hoffman, Beth Necowitz; Leff, Stephen S

    2011-01-01

    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.

  19. Defining Physiologically “Normal” Vitamin D in African Americans

    PubMed Central

    Wright, Nicole C.; Chen, Lang; Niu, Jingbo; Neogi, Tuhina; Javiad, Kassim; Nevitt, Michael A.; Lewis, Cora E.; Curtis, Jeffrey R.

    2013-01-01

    Purpose Vitamin D levels ≥30 ng/ml are commonly considered “normal” based upon maximal suppression of intact parathyroid hormone (iPTH); however, this has recently been challenged and the optimal 25(OH)D level among non-Caucasians is unclear. We evaluated the cross-sectional relationship between serum 25(OH)D and iPTH in a sample of Caucasian and African American adults. Method We used baseline serum samples of participants from the Multicenter Osteoarthritis Study (MOST) for this analysis, and used three methods to model the relationship between 25(OH)D and iPTH: ordinary least squares regression (OLS), segmented regression, and Helmert contrasts. Results Among Caucasians (n=1,258), 25(OH)D and iPTH ranged from 4-51 ng/ml and 2-120 pg/ml and from 3-32 ng/ml and 3-119 pg/ml in African Americans (n=423). We observed different thresholds between African Americans and Caucasians using each analytic technique. Using 25(OH)D as a categorical variable in OLS, iPTH was statistically higher at lower 25(OH)D categories than the 24-32 ng/ml referent group among Caucasians. However, in African Americans, the mean iPTH was only significantly higher at 25(OH)D levels below 15 ng/ml. Using segmented regression, iPTH appeared to stabilize at a lower 25(OH)D level in African Americans (19-23 ng/ml) compared to in Caucasians (>32 ng/ml). Helmert contrasts also revealed a lower threshold in African Americans than Caucasians. Conclusion Among MOST participants, the 25(OH)D thresholds at which no further change in iPTH was observed was approximately 20 ng/ml in African Americans versus approximately 30 ng/ml in Caucasians, suggesting optimal vitamin D levels in Caucasians may not be applicable to African Americans. PMID:22189572

  20. A Bibliography of African Languages and Linguistics.

    ERIC Educational Resources Information Center

    Murphy, John D., Comp.; Goff, Harry, Comp.

    The present bibliography of African languages and linguistics includes not only works relating to the "Negro-African" languages, but also those dealing with the African varieties of Arabic, the Hamitic languages, Malagasy, Afrikaans, and various Creoles. (The greater part of the entries relate to the indigenous languages of the African continent…

  1. Cosmic shear covariance: the log-normal approximation

    NASA Astrophysics Data System (ADS)

    Hilbert, S.; Hartlap, J.; Schneider, P.

    2011-12-01

    Context. Accurate estimates of the errors on the cosmological parameters inferred from cosmic shear surveys require accurate estimates of the covariance of the cosmic shear correlation functions. Aims: We seek approximations to the cosmic shear covariance that are as easy to use as the common approximations based on normal (Gaussian) statistics, but yield more accurate covariance matrices and parameter errors. Methods: We derive expressions for the cosmic shear covariance under the assumption that the underlying convergence field follows log-normal statistics. We also derive a simplified version of this log-normal approximation by only retaining the most important terms beyond normal statistics. We use numerical simulations of weak lensing to study how well the normal, log-normal, and simplified log-normal approximations as well as empirical corrections to the normal approximation proposed in the literature reproduce shear covariances for cosmic shear surveys. We also investigate the resulting confidence regions for cosmological parameters inferred from such surveys. Results: We find that the normal approximation substantially underestimates the cosmic shear covariances and the inferred parameter confidence regions, in particular for surveys with small fields of view and large galaxy densities, but also for very wide surveys. In contrast, the log-normal approximation yields more realistic covariances and confidence regions, but also requires evaluating slightly more complicated expressions. However, the simplified log-normal approximation, although as simple as the normal approximation, yields confidence regions that are almost as accurate as those obtained from the log-normal approximation. The empirical corrections to the normal approximation do not yield more accurate covariances and confidence regions than the (simplified) log-normal approximation. Moreover, they fail to produce positive-semidefinite data covariance matrices in certain cases, rendering them

  2. Macronutrient Intake Influences the Effect of 25-Hydroxy-Vitamin D Status on Metabolic Syndrome Outcomes in African American Girls

    PubMed Central

    Newton, Anna L.; Hanks, Lynae J.; Ashraf, Ambika P.; Williams, Elizabeth; Davis, Michelle; Casazza, Krista

    2012-01-01

    The objectives were to determine the effect of macronutrient modification on vitamin D status and if change in 25-hydroxy-vitamin D concentration influences components of metabolic syndrome in obese African American girls. Methods. Five-week intervention using reduced CHO (43% carbohydrate; 27% fat: SPEC) versus standard CHO (55% carbohydrate; 40% fat: STAN) eucaloric diet. Subjects were 28 obese African American females, aged 9–14 years. Dual energy X-ray absorptiometry and meal test were performed at baseline and five weeks. Results. Approximately 30% of girls had metabolic syndrome. Serum 25OHD increased in both groups at five weeks [STAN: 20.3 ± 1.1 to 22.4 ± 1.1 (P < 0.05) versus SPEC: 16.1 ± 1.0 to 16.8 ± 1.0 (P = 0.05)]. The STAN group, increased 25OHD concentration over five weeks (P < 0.05), which was positively related to triglycerides (P < 0.001) and inversely associated with total cholesterol (P < 0.001) and LDL (P < 0.001). The SPEC group, had increase in 25OHD (P = 0.05), which was positively related to fasting insulin (P < 0.001) and insulin sensitivity while inversely associated with fasting glucose (P < 0.05). The contribution of vitamin D status to metabolic syndrome parameters differs according to macronutrient intake. Improvement in 25OHD may improve fasting glucose, insulin sensitivity, and LDL; however, macronutrient intake warrants consideration. PMID:22792449

  3. 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.

  4. Nursing Positions

    MedlinePlus

    ... breast with your other hand. The Clutch or Football Hold This is also a good position for ... same time may also choose this position. The football hold allows babies to take milk more easily — ...

  5. 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

  6. [African population in history].

    PubMed

    Yang, S

    1984-11-29

    The growth rate of the African population has been fluctuating throughout history, affected by political, social, and economic events. 6000 years ago, the majority of the population was based in North Africa, because farming had been developed there. However, between the 11th and the 16th centuries, there was a constant decline in the population of that region, due to invasions from Europe and the black plague. During the same period, the population in the area south of the Sahara grew rapidly, as people there had gone into the iron tool period and farming had been developed. From the 16th to the mid-17th Century, population growth was considerable in Africa; more people had learned the technology of irrigation, corn and potatoes had been introduced from South America, and colonialism was not yet an issue. From the mid-17th to the mid-19th Century, there was no growth, due to the slave trade and wars between tribes. One estimate sets the direct and indirect loss during this period, as a result of the slave trade, at 100 million people. From the 1850s to the end of World War I, population growth started up again, chiefly influenced by the fact that the slave trade had essentially come to a half and modern medical care had become available on the continent. However, in central Africa, the region which suffered the worst blow from the slave trade, growth was very slow, while in East Africa the population was declining because of wars between colonists and natives, as well as natural disasters. Increases in population during this period were a result of immigration from Europe and India. From the end of World War I to the present, growth has been rapid, given improvements in medical services and standards of living, while most of the former colonies became independent after the 1950s. Consequently, almost all African countries are under great pressure now with regard to their populations.

  7. Central African Republic.

    PubMed

    1989-11-01

    The Central African Republic contains 242,000 square miles, which rolling terrain almost 2000 feet above sea level. The climate is tropical, and it has a population of 2.8 million people with a 2.5% growth rate. There are more than 80 ethnic groups including Baya 34%, Banda 28%, Sara 10%, Mandja 9%, Mboum 9%, and M'Baka 7%. The religions are traditional African 35%, protestant 25%, Roman Catholic 25%, and Muslim 15%, and the languages are French and Sangho. The infant mortality rate is 143/1000, with expectancy at 49 years and a 40% literacy rate. The work force of 1 million is 70% agricultural, industry 6% and commerce and service 6% and government 3%. The government consists of a president assisted by cabinet ministers and a single party. Natural resources include diamonds, uranium, timber, gold, and oil, and major industries are beverages, textiles, and soap. Agricultural products feature coffee, cotton, peanuts, tobacco, food crops and livestock. Most of the population live in rural areas and most of the 80 ethnic groups have their own language. This is one of the world's least developed countries, with a per capita income of $375/year. The main problems with development are the poor transportation infrastructure, and the weak internal and international marketing systems. The US and various international organizations have aided in agriculture development, health programs, and family planning. US investment is mainly in diamond and gold mining, and although oil drilling has been successful it is not economically feasible at current prices.

  8. 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…

  9. Detecting directional selection in the presence of recent admixture in African-Americans.

    PubMed

    Lohmueller, Kirk E; Bustamante, Carlos D; Clark, Andrew G

    2011-03-01

    We investigate the performance of tests of neutrality in admixed populations using plausible demographic models for African-American history as well as resequencing data from African and African-American populations. The analysis of both simulated and human resequencing data suggests that recent admixture does not result in an excess of false-positive results for neutrality tests based on the frequency spectrum after accounting for the population growth in the parental African population. Furthermore, when simulating positive selection, Tajima's D, Fu and Li's D, and haplotype homozygosity have lower power to detect population-specific selection using individuals sampled from the admixed population than from the nonadmixed population. Fay and Wu's H test, however, has more power to detect selection using individuals from the admixed population than from the nonadmixed population, especially when the selective sweep ended long ago. Our results have implications for interpreting recent genome-wide scans for positive selection in human populations.

  10. "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

  11. African Passages: Journaling through Archetypes.

    ERIC Educational Resources Information Center

    Spencer, Patricia

    1990-01-01

    Explores how students (through an awareness of literary archetypes and journal writing) can use African stories to cross cultures, time, and continents, making connections between their worlds and the worlds of others. (MG)

  12. 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)

  13. African-Americans and Alzheimer's

    MedlinePlus

    ... African-Americans are at a higher risk for Alzheimer's disease. Many Americans dismiss the warning signs of Alzheimer's, ... two times more likely to develop late-onset Alzheimer's disease than whites and less likely to have a ...

  14. 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

  15. 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.

  16. 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.

  17. Hepatitis C in African Americans.

    PubMed

    Saab, Sammy; Jackson, Christian; Nieto, Jose; Francois, Fritz

    2014-10-01

    The care of hepatitis C virus (HCV) in African Americans represents an opportunity to address a major health disparity in medicine. In all facets of HCV infection, African Americans are inexplicably affected, including in the prevalence of the virus, which is higher among them compared with most of the racial and ethnic groups. Ironically, although fibrosis rates may be slow, hepatocellular carcinoma and mortality rates appear to be higher among African Americans. Sustained viral response (SVR) rates have historically significantly trailed behind Caucasians. The reasons for this gap in SVR are related to both viral and host factors. Moreover, low enrollment rates in clinical trials hamper the study of the efficacy of anti-viral therapy. Nevertheless, the gap in SVR between African Americans and Caucasians may be narrowing with the use of direct-acting agents. Gastroenterologists, hepatologists, primary care physicians, and other health-care providers need to address modifiable risk factors that affect the natural history, as well as treatment outcomes, for HCV among African Americans. Efforts need to be made to improve awareness among health-care providers to address the differences in screening and referral patterns for African Americans.

  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. 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…

  20. 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 …

  1. 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…

  2. 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…

  3. As Latino Populations Grow, So Does Their Power. Will They Compete or Cooperate with African Americans for Academic Clout?

    ERIC Educational Resources Information Center

    Weiger, Pamela R.

    2000-01-01

    Examines perceptions that African Americans must compete with Hispanics for faculty and administrative positions at Arizona State University. School officials deny replacing African American employees with Hispanics, suggesting that isolated incidents might make people believe this is occurring. Data are provided on Hispanic higher education…

  4. 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…

  5. 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,…

  6. 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…

  7. 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…

  8. 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…

  9. Signal Approximation with a Wavelet Neural Network

    DTIC Science & Technology

    1992-12-01

    specialized electronic devices like the Intel Electronically Trainable Analog Neural Network (ETANN) chip. The WNN representation allows the...accurately approximated with a WNN trained with irregularly sampled data. Signal approximation, Wavelet neural network .

  10. Rough Set Approximations in Formal Concept Analysis

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Daisuke; Murata, Atsuo; Li, Guo-Dong; Nagai, Masatake

    Conventional set approximations are based on a set of attributes; however, these approximations cannot relate an object to the corresponding attribute. In this study, a new model for set approximation based on individual attributes is proposed for interval-valued data. Defining an indiscernibility relation is omitted since each attribute value itself has a set of values. Two types of approximations, single- and multiattribute approximations, are presented. A multi-attribute approximation has two solutions: a maximum and a minimum solution. A maximum solution is a set of objects that satisfy the condition of approximation for at least one attribute. A minimum solution is a set of objects that satisfy the condition for all attributes. The proposed set approximation is helpful in finding the features of objects relating to condition attributes when interval-valued data are given. The proposed model contributes to feature extraction in interval-valued information systems.

  11. 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

  12. Multidimensional Approximation Operators Generated by Lebesgue-Stieltjes Measures

    NASA Astrophysics Data System (ADS)

    Volkov, Yu I.

    1984-06-01

    A general class of sequences of multidimensional positive linear operators is defined and studied; it includes, in particular, sequences of multidimensional Berstein polynomials. The main asymptotic term is obtained in the remainder when derivatives of functions in certain classes are approximated by derivatives of the values of the operators on these functions. Bibliography: 10 titles.

  13. 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…

  14. African absolute plate motion and True Polar Wander at about 50Ma

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Wessel, P.

    2011-12-01

    Using new data set of seamount ages on the African plate, a model of motion of the African plate relative to the African hotspots are calculated by the Polygonal Finite Rotation Method; PFRM (Harada and Hamano, 2000). The new motion of the African plate has more abrupt change at about 50Ma than the previous models of the African plate mainly due to the PFRM which can allow the finite pole of the plate rotation to move continuously. The new model of the motion fits positions and ages of the almost all seamounts which are created by the African hotspots, whereas the previous models do not fit with positions of northwestern hotspots of the African plate such as Canary, Cape Verde, Meteor and Bathymetric hotspot. The new model suggests that the African plate rotated counter clockwise abruptly at about 50Ma. To compare the 50Ma abrupt change with coeval event at the Pacific plate motion, we utilized the paleomagnetic data from both plates. From the apparent geomagnetic polar wander path of the African plate and African plate motion relative to the African hotspots, we calculated geomagnetic polar motion relative to the African hotspots. Similarly, we calculated geomagnetic polar motion relative to the Pacific hotspots from the Pacific sets of paleomagnetic data and plate motion. The geomagnetic polar motion or true polar wander should be only one, therefore we can calculate relative motion of the African hotspots and the Pacific hotspots. The result shows that there was no significant motion between two groups of hotspots since about 70Ma. The new true polar wander path since 70Ma, thus, presented by averaging the two models of motions, and this has about 90 degree clockwise change of directions at about 50Ma. This study strongly suggests below. 1, There was coeval event of the African plate motion with Hawaii-Emperor bend event at the Pacific plate. 2, There was no significant relative motion between global hotspots for the time scale of 70Myr even though there was

  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.

  16. 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.

  17. Energy conservation - A test for scattering approximations

    NASA Technical Reports Server (NTRS)

    Acquista, C.; Holland, A. C.

    1980-01-01

    The roles of the extinction theorem and energy conservation in obtaining the scattering and absorption cross sections for several light scattering approximations are explored. It is shown that the Rayleigh, Rayleigh-Gans, anomalous diffraction, geometrical optics, and Shifrin approximations all lead to reasonable values of the cross sections, while the modified Mie approximation does not. Further examination of the modified Mie approximation for the ensembles of nonspherical particles reveals additional problems with that method.

  18. African-American parents' racial and ethnic socialization and adolescent academic grades: teasing out the role of gender.

    PubMed

    Brown, Tiffany L; Linver, Miriam R; Evans, Melanie; DeGennaro, Donna

    2009-02-01

    This study examined the relationship of racial and ethnic socialization and academic achievement in a sample of 218 African American adolescents (grades 9-12; 52% girls) attending a public high school in the northeastern United States. Researchers were particularly interested in whether adolescent gender moderated the relationship between racial and ethnic socialization and academic grades. Results indicated that aspects of ethnic socialization, African American cultural values and African American heritage were linked to adolescent grades. Additionally, adolescent gender was found to moderate the association between these socialization variables and grades. The findings also suggest that socialization provided by paternal caregivers around African American cultural values and African American heritage may have differential effects for academic grades than the socialization messages provided by maternal caregivers. Information generated from this study broadens the understanding of socialization factors that can facilitate positive academic outcomes in African American youth and has practical implications for parents and educators.

  19. Compressive Imaging via Approximate Message Passing

    DTIC Science & Technology

    2015-09-04

    We propose novel compressive imaging algorithms that employ approximate message passing (AMP), which is an iterative signal estimation algorithm that...Approved for Public Release; Distribution Unlimited Final Report: Compressive Imaging via Approximate Message Passing The views, opinions and/or findings...Research Triangle Park, NC 27709-2211 approximate message passing , compressive imaging, compressive sensing, hyperspectral imaging, signal reconstruction

  20. 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.

  1. Obesity intervention among African-American children and adolescents.

    PubMed

    Baskin, M L; Ahluwalia, H K; Resnicow, K

    2001-08-01

    Often, researchers and clinicians approach the African-American community from a deficit model with African Americans viewed as having less desirable health practices and higher disease risk; however, in developing interventions for African Americans, it is important to keep in mind positive aspects of black culture as they relate to obesity. For example, the cultural acceptance of a larger body type and less negative views toward overweight individuals need not be viewed as problematic or abnormal. In fact, it could be argued that majority culture has a dysfunctional view of body image and obesity. The fact that whites are less likely to be overweight than African Americans may stem from a value system that places undue emphasis on thinness, youth, and external beauty and a culture that imbues women with shame about how they look and what they eat. Thus, rather than holding whites and majority culture as the ideal, it may be important to incorporate the positive elements of black culture regarding body image and food rather than attempting to shift their values toward those of European Americans. How best to achieve a reduction in obesity and its medical consequences, without inducing undesirable shifts in body image and attitudes toward food, is a formidable but important challenge.

  2. 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…

  3. 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).

  4. 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.".

  5. Tuberculosis in African Americans: clinical characteristics and outcome.

    PubMed Central

    Funnyé, A. S.; Ganesan, K.; Yoshikawa, T. T.

    1998-01-01

    This study examined the clinical characteristics and outcome of pulmonary tuberculosis in African Americans hospitalized in a teaching hospital in south-central Los Angeles from May 1992 through April 1994. The charts of 41 African Americans with culture-positive Mycobacterium tuberculosis were reviewed. Predisposing factors for pulmonary tuberculosis were identified in nearly half of cases. Cough and fever were the most common symptoms. Seventy-six percent had positive acid-fast bacilli (AFB) smears. Nine patients were human immunodeficiency virus (HIV)-positive, and 6 of 9 HIV-positive patients had positive AFB smears whereas 17 of 19 HIV-negative patients had positive AFB smears. Radiographic changes were not significantly different between HIV-positive and HIV-negative patients. Drug resistance was identified in nine of 31 patients (29%). Eight of 41 patients (19.5%) died, with 2 being drug resistant. Human immunodeficiency virus infection was a major predisposing factor for tuberculosis, and no statistical differences were found in radiographic features or AFB smear positivity between HIV-positive and HIV-negative patients. Drug resistance and mortality were disproportionately high. These results indicate that HIV infection and drug resistance are major problems that predispose for tuberculosis infection and make its treatment difficult. PMID:9510620

  6. An Approximate Approach to Automatic Kernel Selection.

    PubMed

    Ding, Lizhong; Liao, Shizhong

    2016-02-02

    Kernel selection is a fundamental problem of kernel-based learning algorithms. In this paper, we propose an approximate approach to automatic kernel selection for regression from the perspective of kernel matrix approximation. We first introduce multilevel circulant matrices into automatic kernel selection, and develop two approximate kernel selection algorithms by exploiting the computational virtues of multilevel circulant matrices. The complexity of the proposed algorithms is quasi-linear in the number of data points. Then, we prove an approximation error bound to measure the effect of the approximation in kernel matrices by multilevel circulant matrices on the hypothesis and further show that the approximate hypothesis produced with multilevel circulant matrices converges to the accurate hypothesis produced with kernel matrices. Experimental evaluations on benchmark datasets demonstrate the effectiveness of approximate kernel selection.

  7. Beauty is in the soul of the beholder: psychological implications of beauty and African American women.

    PubMed

    Hall, C C

    1995-01-01

    The criteria for beauty in the United States are primarily based on Caucasian European American, middle-class standards. African American women tend to vary greatly from these criteria. Though very few studies have been conducted on the body image of Black women in the United States, historically, the physical images portrayed of African American women in the United States have not been positive. Mental health practitioners must understand how these negative images may affect the body image and self-esteem of African American women. Therapeutic and community interventions are discussed.

  8. 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

  9. 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.

  10. 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…

  11. Nursing Positions

    MedlinePlus

    ... and actually needs to feed. Getting Comfortable With Breastfeeding Nursing can be one of the most challenging ... a mother. As you become more used to breastfeeding your baby, you can try different positions or ...

  12. 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)

  13. 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

  14. Soft tissue thickness values for black and coloured South African children aged 6-13 years.

    PubMed

    Briers, N; Briers, T M; Becker, P J; Steyn, M

    2015-07-01

    In children, craniofacial changes due to facial growth complicate facial approximations and require specific knowledge of soft tissue thicknesses (STT). The lack of South African juvenile STT standards of particular age groups, sex and ancestry is problematic. According to forensic artists in the South African Police Service the use of African-American values to reconstruct faces of Black South African children yields poor results. In order to perform a facial approximation that presents a true reflection of the child in question, information regarding differences in facial soft tissue at different ages, sexes and ancestry groups is needed. The aims of this study were to provide data on STT of South African Black and Coloured children and to assess differences in STT with respect to age, sex and ancestry. STT was measured using cephalograms of South African children (n=388), aged 6-13 years. After digitizing the images, STT measurements were taken at ten mid-facial landmarks from each image using the iTEM measuring program. STT comparisons between groups per age, sex and ancestry were statistically analyzed. The results showed that STT differences at lower face landmarks are more pronounced in age groups per ancestry as opposed to differences per age and sex. Generally, an increase in STT was seen between 6-10 year old groups and 11-13 year old groups, regardless of ancestry and sex, at the midphiltrum, labiale inferius, pogonion, and beneath chin landmarks. This research created a reference dataset for STT of South African children of Black and Coloured ancestry per age and sex that will be useful for facial reconstruction/approximation of juvenile remains.

  15. 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…

  16. 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.

  17. Type 2 diabetes mellitus in African women.

    PubMed

    Goedecke, Julia H; Mtintsilana, Asanda; Dlamini, Siphiwe N; Kengne, Andre Pascal

    2017-01-01

    Compared to global estimates, Sub-Saharan Africa (SSA) has the highest projected rates of increase in type 2 diabetes (T2D) over the next 25years. This is attributed to the ageing population, increasing urbanisation and the associated lifestyle changes. Although the prevalence does not differ by gender, deaths attributable to T2D in SSA are greater in women, likely due to differences in beliefs and access to care. Women in SSA also have greater risk factor burden for T2D than men, in particular obesity, which is explained in part by sociocultural factors. The pathogenesis of diabetes differs between African and Caucasian women, with implications for risk assessment. African women are more insulin resistant than their Caucasian counterparts, despite a more 'favourable' body fat distribution. Notably, women in SSA face the dual burden of T2D and HIV/AIDS. HIV positive women in SSA are typically young and obese, with the latter being exacerbated by anti-retroviral therapy (ART). Cultural perceptions regarding weight loss and limited financial resources are the major limitations to the management of T2D. Hence prevention is vital. However, there is a paucity of studies examining the effectiveness and sustainability of interventions to reduce T2D in SSA.

  18. 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

  19. Biological and Genomic Differences of ERG Oncoprotein-Stratified Prostate Cancers from African and Caucasian Americans

    DTIC Science & Technology

    2014-10-01

    for AfricanAmerican ( AA ) men as compared to Caucasian Americans (CA). Biological basis for this disparity has not been established. Oncogenic...underlying biological or genetic differences of prostate cancer (CaP) incidence and/or progression between African American ( AA ) and Caucasian American (CA...positive and ERG negative CaP. It is anticipated that molecular determinants of aggressive CaP in AA men include somatic mutations (TMPRSS2-ERG

  20. 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.

  1. 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.

  2. 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.

  3. African perceptions of female attractiveness.

    PubMed

    Coetzee, Vinet; Faerber, Stella J; Greeff, Jaco M; Lefevre, Carmen E; Re, Daniel E; Perrett, David I

    2012-01-01

    Little is known about mate choice preferences outside Western, educated, industrialised, rich and democratic societies, even though these Western populations may be particularly unrepresentative of human populations. To our knowledge, this is the first study to test which facial cues contribute to African perceptions of African female attractiveness and also the first study to test the combined role of facial adiposity, skin colour (lightness, yellowness and redness), skin homogeneity and youthfulness in the facial attractiveness preferences of any population. Results show that youthfulness, skin colour, skin homogeneity and facial adiposity significantly and independently predict attractiveness in female African faces. Younger, thinner women with a lighter, yellower skin colour and a more homogenous skin tone are considered more attractive. These findings provide a more global perspective on human mate choice and point to a universal role for these four facial cues in female facial attractiveness.

  4. 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.

  5. 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.

  6. 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.

  7. Restricted second random phase approximations and Tamm-Dancoff approximations for electronic excitation energy calculations.

    PubMed

    Peng, Degao; Yang, Yang; Zhang, Peng; Yang, Weitao

    2014-12-07

    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(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.

  8. 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)

  9. 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…

  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. Increasing Reading Engagement in African American Boys

    ERIC Educational Resources Information Center

    Husband, Terry

    2014-01-01

    Much has been written concerning the challenges many teachers face in engaging African American males in reading practices. While much of this extant scholarship focuses on African American males at the pre-adolescent stage of development and beyond, little has been written regarding increasing reading engagement in African American boys in P-5…

  12. African Expressions in Hispano-American Literature.

    ERIC Educational Resources Information Center

    Coleman, Ben C.

    This revised version of a lecture on the relationship of African language and Hispano-American literature illustrates the historical influence of the African slave on representative literature and modern culture of the Caribbean Islands. Introductory remarks focus on the migratory patterns of the African slaves. The concept of negritude is then…

  13. 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…

  14. Empowering African genomics for infectious disease control.

    PubMed

    Folarin, Onikepe A; Happi, Anise N; Happi, Christian T

    2014-11-07

    At present, African scientists can only participate minimally in the genomics revolution that is transforming the understanding, surveillance and clinical treatment of infectious diseases. We discuss new initiatives to equip African scientists with knowledge of cutting-edge genomics tools, and build a sustainable critical mass of well-trained African infectious diseases genomics scientists.

  15. Determinants of woody cover in African savannas.

    PubMed

    Sankaran, Mahesh; Hanan, Niall P; Scholes, Robert J; Ratnam, Jayashree; Augustine, David J; Cade, Brian S; Gignoux, Jacques; Higgins, Steven I; Le Roux, Xavier; Ludwig, Fulco; Ardo, Jonas; Banyikwa, Feetham; Bronn, Andries; Bucini, Gabriela; Caylor, Kelly K; Coughenour, Michael B; Diouf, Alioune; Ekaya, Wellington; Feral, Christie J; February, Edmund C; Frost, Peter G H; Hiernaux, Pierre; Hrabar, Halszka; Metzger, Kristine L; Prins, Herbert H T; Ringrose, Susan; Sea, William; Tews, Jörg; Worden, Jeff; Zambatis, Nick

    2005-12-08

    Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in regulating woody cover, but perceptions differ on which of these are the primary drivers of savanna structure. Here we show, using data from 854 sites across Africa, that maximum woody cover in savannas receiving a mean annual precipitation (MAP) of less than approximately 650 mm is constrained by, and increases linearly with, MAP. These arid and semi-arid savannas may be considered 'stable' systems in which water constrains woody cover and permits grasses to coexist, while fire, herbivory and soil properties interact to reduce woody cover below the MAP-controlled upper bound. Above a MAP of approximately 650 mm, savannas are 'unstable' systems in which MAP is sufficient for woody canopy closure, and disturbances (fire, herbivory) are required for the coexistence of trees and grass. These results provide insights into the nature of African savannas and suggest that future changes in precipitation may considerably affect their distribution and dynamics.

  16. The JWKB approximation in loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Craig, David; Singh, Parampreet

    2017-01-01

    We explore the JWKB approximation in loop quantum cosmology in a flat universe with a scalar matter source. Exact solutions of the quantum constraint are studied at small volume in the JWKB approximation in order to assess the probability of tunneling to small or zero volume. Novel features of the approximation are discussed which appear due to the fact that the model is effectively a two-dimensional dynamical system. Based on collaborative work with Parampreet Singh.

  17. Approximate dynamic model of a turbojet engine

    NASA Technical Reports Server (NTRS)

    Artemov, O. A.

    1978-01-01

    An approximate dynamic nonlinear model of a turbojet engine is elaborated on as a tool in studying the aircraft control loop, with the turbojet engine treated as an actuating component. Approximate relationships linking the basic engine parameters and shaft speed are derived to simplify the problem, and to aid in constructing an approximate nonlinear dynamic model of turbojet engine performance useful for predicting aircraft motion.

  18. Heart failure in African Americans.

    PubMed

    Yancy, Clyde W

    2005-10-10

    The demographics of the United States are changing, and in the next few decades there will no longer be a racial/ethnic majority population. Increased awareness of cardiovascular disease (CVD) in special populations is warranted as these populations increase. Heart failure carries a substantial burden on those affected, particularly African Americans, who have a disproportionate burden of heart disease. Current treatments for heart failure include angiotensin-converting enzyme inhibitors, beta-blockers, angiotensin II-receptor antagonists, and vasodilating agents. This review discusses the unique characteristics of CVD in African Americans and addresses the need for targeted treatments to reduce the excess burden found in this population.

  19. South African, urban youth narratives: Resilience within community

    PubMed Central

    Ahmed, Rashid; Ports, Katie A.; Simon, Christian

    2013-01-01

    South African youth in low-income, urbanized communities are exposed to high levels of daily stressors, which increase their risk to negative outcomes. Resiliency can provide avenues for youth to transcend adversity and may contribute to their positive development. To provide a deeper understanding of the pathways that adolescents use to overcome adversity, this paper examined future aspirations of South African youth, and how these aspirations were connected to resiliency factors framed by their lived context. A phenomenological approach was used to explore the perceptions of high school students. Fourteen focus groups with girls and boys (N=112) were conducted. Data was analyzed using a thematic approach. Discussions of the harsh conditions undermining the community’s future highlighted opportunities for improvement. Community connectedness, hope and altruism were prevalent in youth’s responses and could be used to facilitate community and individual resiliency. Our overall findings have important implications for positive youth development efforts. PMID:25897181

  20. Bent approximations to synchrotron radiation optics

    SciTech Connect

    Heald, S.

    1981-01-01

    Ideal optical elements can be approximated by bending flats or cylinders. This paper considers the applications of these approximate optics to synchrotron radiation. Analytic and raytracing studies are used to compare their optical performance with the corresponding ideal elements. It is found that for many applications the performance is adequate, with the additional advantages of lower cost and greater flexibility. Particular emphasis is placed on obtaining the practical limitations on the use of the approximate elements in typical beamline configurations. Also considered are the possibilities for approximating very long length mirrors using segmented mirrors.

  1. Position sense asymmetry.

    PubMed

    Adamo, Diane E; Martin, Bernard J

    2009-01-01

    Asymmetries in upper limb position sense have been explained in the context of a left limb advantage derived from differences in hemispheric specialization in the processing of kinesthetic information. However, it is not clearly understood how the comparison of perceptual information associated with passive limb displacement and the corresponding matching movement resulting from the execution of a motor command contributes to these differences. In the present study, upper limb position sense was investigated in 12 right-hand-dominant young adults performing wrist position matching tasks which varied in terms of interhemispheric transfer, memory retrieval and whether the reference position was provided by the same or opposite limb. Right and left hand absolute matching errors were similar when the reference and matching positions were produced by the same hand but were 36% greater when matching the reference position with the opposite hand. When examining the constant errors generated from matching movements made with the same hand that provided the reference, the right and left hand matching errors (approximately 3 degrees) were similar. However, when matching with the opposite limb, a large overshoot (P < 0.05) characterized the error when the right hand matched the left hand reference while a large undershoot (P < 0.05) characterized the error when the left hand matched the right hand reference. The overshoot and undershoot were of similar magnitude (approximately 4 degrees). Although asymmetries in the central processing of proprioceptive information such as interhemispheric transfer may exist, the present study suggests that asymmetries in position sense predominantly result from a difference in the "gain of the respective proprioceptive sensory-motor loops". This new hypothesis is strongly supported by a dual-linear model representing the right and left hand sensory-motor systems as well as morphological and physiological data.

  2. The Role of the African Union in African Peacekeeping Operations

    DTIC Science & Technology

    2008-03-26

    Government in Sirte , Libya, on 9 September 1999. The AU was formed to address some of the issues identified during the analysis of the OAU PKOs. The...Establishment of the African Union The Sirte Declaration led to the establishment of the AU in 2002. One of the AU’s objectives was to enhance the security

  3. 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…

  4. 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…

  5. Factors Contributing to the Underperformance of African American Boys in K-3 Reading

    ERIC Educational Resources Information Center

    Younger, Queietasha

    2014-01-01

    African American male students in elementary schools are scoring approximately 30% lower than their peers in reading and content areas. There are many factors causing the discrepancy; indeed, the complexity of the problem has inhibited a clear solution. The purpose of this qualitative case study was to examine factors associated with low…

  6. Further constraints on the African superplume structure

    NASA Astrophysics Data System (ADS)

    Ni, Sidao; Helmberger, Don V.

    2003-11-01

    It is well established that there is a large-scale low velocity structure in the lowermost mantle beneath Africa, extending from the Southeastern Atlantic Ocean to the Southwestern Indian Ocean with a volume greater than 10 billion km 3 (>7000 km long, 1000 km across and 1200 km high) [Earth Planet. Sci. Lett. 206 (2003) 119]. This low velocity structure is often called the African superplume. Various studies also require sharp boundaries for the plume. However, as for its height and shear velocity reduction, there has been some controversy, especially concerning the velocities at the core-mantle-boundary (CMB). Here, we present an assortment of phases involving S diff, SKS, S and S cS with both vertical and horizontal paths sampling a 2D corridor through the structure. Travel time and waveform modeling of these seismic phases argues for a model with shear velocity reduction of approximately 3% within the superplume (which is basically a 200 km thick layer low velocity layer beneath the Southern Atlantic Ocean, and a 1200 km high structure beneath South Africa), and against a model of a substantially reduced low velocity layer (up to 10%, 300 km) beneath the superplume. We also analyzed P diff and the differential times of P cP-P and compared them with S diff and S cS-S observations along the same great circle paths. The P-velocity is not very anomalous, at most -0.5%, much smaller than -1% as expected from a thermal anomaly with -3% lower S-velocity [Geophys. Res. Lett. 27 (2000) 421], thus again arguing for a chemical origin which was suggested from the modeling of African superplume sharp sides [Science 296 (2002) 1850].

  7. 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.

  8. Chitotriosidase deficiency: a mutation update in an african population.

    PubMed

    Arndt, Silke; Hobbs, Angela; Sinclaire, Iain; Lane, Anthony B

    2013-01-01

    Human plasma chitotriosidase activity is a commonly used diagnostic and therapeutic biomarker for non-neuronopathic Gaucher disease. Chitotriosidase deficiency is common in non-African populations and is primarily caused by a 24 bp duplication in the encoding gene (CHIT1). Allele frequencies for the 24 bp duplication range from 20-50 % outside Africa. The present study found chitotriosidase deficiency to be rare in the South African Black population (1.6 %) and the otherwise common 24 bp duplication is absent in this African population. Instead, chitotriosidase deficiency is caused by a 4 bp deletion across the exon/intron 10 boundary (E/I-10_delGAgt) of the CHIT1 gene. The exact position of this mutation was found to differ from the previously reported location. Allele frequencies for six coding variants of CHIT1 (p.G102S, p.G354R, 24 bp duplication, E/I-10_delGAgt, p.A442V/G) were determined and the 4 bp deletion was found to be in complete linkage disequilibrium (LD) with two of the coding variants (p.G354R and p.A442V). The in silico assessments of the two missense mutations in LD predict a protein-damaging nature and functional studies are needed to clarify if one or both abolish the enzyme's activity. Overall, the low frequency of chitotriosidase deficiency in South African Blacks makes chitotriosidase activity an excellent biomarker of choice in this population.

  9. Publishing South African scholarship in the global academic community

    PubMed Central

    le Roux, Elizabeth

    2015-01-01

    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

  10. Transcutaneous bilirubin nomograms in African neonates

    PubMed Central

    Mabogunje, Cecilia A.; Imosemi, Donald O.; Emokpae, Abieyuwa A.

    2017-01-01

    Background The use of transcutaneous bilirubin (TcB) as a screening tool, based on relevant population-specific nomogram, or proxy for total serum bilirubin (TSB) levels in assessing the risk of subsequent hyperbilirubinemia is supported by several clinical guidelines on the management of neonatal hyperbilirubinemia. However, while TcB has been found to significantly over-estimate TSB in neonates of African-American ancestry, with variations across TcB devices, no nomogram has been specifically reported for this racial group. This study therefore set out to develop TcB nomograms for healthy late pre-term and term black African neonates derived from two widely used bilirubinometers. Methods A retrospective analysis of 12,377 TcB measurements obtained from 6,373 neonates in the first postnatal week, over a period of 48 months using Bilichek and JM-103 bilirubinometers. TcB percentiles were computed from hour-specific TcB values and nomograms developed for each of the screening devices. Predictive ability of the 75th and 95th percentiles to detect significant hyperbilirubinemia was evaluated between 24–96 hours of age. The 95th percentile curve was compared with those from other populations. Results The velocity of TcB rise at 75th and 95th percentiles was generally higher with JM-103 than Bilichek. Both percentiles also peaked at higher TcB levels with JM-103. The 95th percentile for both instruments showed a downward trend as from approximately 114 hours. Both instruments had high negative predictive values across the selected time-epochs and lower discriminatory ability than reported in non-black populations. Conclusions The predictive utility of TcB as a potential screening tool varies across devices in black African neonates with or without risk of significant hyperbilirubinemia, and lower than levels reported in non-black populations. Equipment-specific nomograms should be considered for TcB monitoring in this racial population where TSB is not routinely

  11. Family Wide Molecular Adaptations to Underground Life in African Mole-Rats Revealed by Phylogenomic Analysis.

    PubMed

    Davies, Kalina T J; Bennett, Nigel C; Tsagkogeorga, Georgia; Rossiter, Stephen J; Faulkes, Christopher G

    2015-12-01

    During their evolutionary radiation, mammals have colonized diverse habitats. Arguably the subterranean niche is the most inhospitable of these, characterized by reduced oxygen, elevated carbon dioxide, absence of light, scarcity of food, and a substrate that is energetically costly to burrow through. Of all lineages to have transitioned to a subterranean niche, African mole-rats are one of the most successful. Much of their ecological success can be attributed to a diet of plant storage organs, which has allowed them to colonize climatically varied habitats across sub-Saharan Africa, and has probably contributed to the evolution of their diverse social systems. Yet despite their many remarkable phenotypic specializations, little is known about molecular adaptations underlying these traits. To address this, we sequenced the transcriptomes of seven mole-rat taxa, including three solitary species, and combined new sequences with existing genomic data sets. Alignments of more than 13,000 protein-coding genes encompassed, for the first time, all six genera and the full spectrum of ecological and social variation in the clade. We detected positive selection within the mole-rat clade and along ancestral branches in approximately 700 genes including loci associated with tumorigenesis, aging, morphological development, and sociality. By combining these results with gene ontology annotation and protein-protein networks, we identified several clusters of functionally related genes. This family wide analysis of molecular evolution in mole-rats has identified a suite of positively selected genes, deepening our understanding of the extreme phenotypic traits exhibited by this group.

  12. 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).

  13. African-American spirituality: a concept analysis.

    PubMed

    Newlin, Kelley; Knafl, Kathleen; Melkus, Gail D'Eramo

    2002-12-01

    Culturally competent care for African Americans requires sensitivity to spirituality as a component of the cultural context. To foster understanding, measurement, and delivery of the spiritual component of culturally competent care, this article presents an evolutionary concept analysis of African-American spirituality. The analysis is based on a sample of multidisciplinary research studies reflecting spirituality of African Americans. Findings indicate that African-American spirituality involves quintessential, internal, external, consoling, and transformative attributive dimensions. Findings are considered in relation to previous conceptual analyses of spirituality and suggest that defining attributes of African-American spirituality are both global and culturally prominent. Implications for practice and research are discussed.

  14. Analytic Interatomic Forces in the Random Phase Approximation

    NASA Astrophysics Data System (ADS)

    Ramberger, Benjamin; Schäfer, Tobias; Kresse, Georg

    2017-03-01

    We discuss that in the random phase approximation (RPA) the first derivative of the energy with respect to the Green's function is the self-energy in the G W approximation. This relationship allows us to derive compact equations for the RPA interatomic forces. We also show that position dependent overlap operators are elegantly incorporated in the present framework. The RPA force equations have been implemented in the projector augmented wave formalism, and we present illustrative applications, including ab initio molecular dynamics simulations, the calculation of phonon dispersion relations for diamond and graphite, as well as structural relaxations for water on boron nitride. The present derivation establishes a concise framework for forces within perturbative approaches and is also applicable to more involved approximations for the correlation energy.

  15. 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.

  16. 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…

  17. Approximate methods for equations of incompressible fluid

    NASA Astrophysics Data System (ADS)

    Galkin, V. A.; Dubovik, A. O.; Epifanov, A. A.

    2017-02-01

    Approximate methods on the basis of sequential approximations in the theory of functional solutions to systems of conservation laws is considered, including the model of dynamics of incompressible fluid. Test calculations are performed, and a comparison with exact solutions is carried out.

  18. 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…

  19. 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.

  20. 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.

  1. 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…

  2. Spirit Wiggles into Position

    NASA Technical Reports Server (NTRS)

    2005-01-01

    NASA's Mars Exploration Rover Spirit completed a difficult, rocky ascent en route to reaching a captivating rock outcrop nicknamed 'Hillary' at the summit of 'Husband Hill.' At the end of the climb the robotic geologist was tilted almost 30 degrees. To get the rover on more solid footing for deploying the instrument arm, rover drivers told Spirit to wiggle its wheels one at a time. This animation shows Spirit's position before and after completing the wheel wiggle, during which the rover slid approximately 1 centimeter (0.4 inch) downhill. Rover drivers decided this position was too hazardous for deploying the instrument arm and subsequently directed Spirit to a more stable position before conducting analyses with instruments on the rover's arm.

    Spirit took these images with its front hazard-avoidance camera on martian day, or sol, 625 (Oct. 6, 2005).

  3. The African Americanization of menthol cigarette use in the United States.

    PubMed

    Gardiner, Phillip S

    2004-02-01

    Today, over 70% of African American smokers prefer menthol cigarettes, compared with 30% of White smokers. This unique social phenomenon was principally occasioned by the tobacco industry's masterful manipulation of the burgeoning Black, urban, segregated, consumer market in the 1960s. Through the use of television and other advertising media, coupled with culturally tailored images and messages, the tobacco industry "African Americanized" menthol cigarettes. The tobacco industry successfully positioned mentholated products, especially Kool, as young, hip, new, and healthy. During the time that menthols were gaining a large market share in the African American community, the tobacco industry donated funds to African American organizations hoping to blunt the attack on their products. Many of the findings in this article are drawn from the tobacco industry documents disclosed following the Master Settlement Agreement in 1998. After a short review of the origins and growth of menthols, this article examines some key social factors that, when considered together, led to disproportionate use of mentholated cigarettes by African Americans compared with other Americans. Unfortunately, the long-term impact of the industry's practice in this community may be partly responsible for the disproportionately high tobacco-related disease and mortality among African Americans generally and African American males particularly.

  4. 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.

  5. 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.

  6. Cryptococcal meningitis in African children.

    PubMed

    Subramanyam, V R; Mtitimila, E; Hart, C A; Broadhead, R L

    1997-06-01

    Three cases of cryptococcal meningitis in Malawian children aged 6 weeks, 3 years and 9 years are described. Only 23 cases of cryptococcal meningitis in children have been described previously, but in children from Europe and the USA. These are therefore the first cases of cryptococcosis to be described in African children.

  7. Wellness among African American Counselors

    ERIC Educational Resources Information Center

    Day-Vines, Norma L.; Holcomb-McCoy, Cheryl

    2007-01-01

    Although there are various definitions of wellness, few conceptual definitions have addressed the contextual dimensions of wellness relative to African American counselors. The authors present an overview of generic models of wellness, discuss factors that both inhibit and promote wellness, offer some culture-specific models of wellness, and…

  8. 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…

  9. Improvisation in West African Musics.

    ERIC Educational Resources Information Center

    Locke, David

    1980-01-01

    Discussed is music of the sub-Sahara. Vocal, instrumental, and dance drumming from the Sudan Desert, the North Coast, East Horn, Central and West Africa, and contrapuntal yodeling of Pygmies is described. For African musicians, the ability to improvise, and creativity, are gifts from God. Includes selected readings and recordings. (KC)

  10. 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

  11. Cytokine profiling of young overweight and obese female African American adults with prediabetes.

    PubMed

    Lucas, Rudolf; Parikh, Samip J; Sridhar, Supriya; Guo, De-Huang; Bhagatwala, Jigar; Dong, Yutong; Caldwell, Ruth; Mellor, Andrew; Caldwell, William; Zhu, Haidong; Dong, Yanbin

    2013-10-01

    Approximately 5-10% of subjects with prediabetes become diabetic every year. Inflammation is involved in the development of obesity-related type 2 diabetes (T2D). However, to date, the relationship between inflammation and prediabetes, defined by hemoglobin A1c (HbA1c) ≥5.7 and <6.5%, remains largely unexplored, especially in African Americans. Therefore, in this study we examined a comprehensive panel of 13 cytokines involved in the inflammatory response in overweight/obese subjects with prediabetes. A total of 21 otherwise healthy, overweight/obese, young adult African American females with prediabetes, together with 20 matched overweight/obese controls, were selected for this study. Plasma cytokines were assessed by multiplex cytokine profiling. Plasma concentrations of interleukin (IL)-5, IL-6, IL-7, tumor necrosis factor-α (TNF-α), and granulocyte-monocyte colony-stimulating factor (GM-CSF) were significantly higher in the prediabetic group, as compared to the control group (all p<0.05). Plasma concentrations of all the other cytokines, interferon-γ (IFN-γ), IL-1β, IL-2, IL-4, IL-8, IL-10, IL-12p70 and IL-13, seemed to be elevated in the prediabetic group, but failed to reach statistical significances. Upon merging both groups, HbA1c was found to be positively correlated with IFN-γ, IL-1β, IL-2, IL-5, IL-7, IL-8, TNF-α and GM-CSF. This study demonstrates elevated levels of various pro-inflammatory cytokines in overweight/obese young subjects with prediabetes, which place them at higher risk of developing T2D and cardiovascular diseases. Our data also call for further investigations in animal models and population cohorts to establish the roles of a variety of pro-inflammatory cytokines in the early development of obesity-related T2D.

  12. 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…

  13. African-American Critical Discourse and the Invention of Cultural Identities.

    ERIC Educational Resources Information Center

    Olaniyan, Tejumola

    1992-01-01

    Reviews issues surrounding African-American cultural identity in cultural discourse about the arts, especially literature. Identifies positions in the current debate, critiques some positions being argued, and focuses on the work of Henry Louis Gates, Jr., in his book, "The Signifying Monkey: A Theory of Afro-American Literacy…

  14. Developing anatomical terms in an African language.

    PubMed

    Madzimbamuto, Farai Daniel

    2012-02-23

    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.

  15. Adiabatic approximation for the Rabi model with broken inversion symmetry

    NASA Astrophysics Data System (ADS)

    Shen, Li-Tuo; Yang, Zhen-Biao; Wu, Huai-Zhi

    2017-01-01

    We study the properties and behavior of the Rabi model with broken inversion symmetry. Using an adiabatic approximation approach, we explore the high-frequency qubit and oscillator regimes, and obtain analytical solutions for the qubit-oscillator system. We demonstrate that, due to broken inversion symmetry, the positions of two potentials and zero-point energies in the oscillators become asymmetric and have a quadratic dependence on the mean dipole moments within the high-frequency oscillator regime. Furthermore, we find that there is a critical point above which the qubit-oscillator system becomes unstable, and the position of this critical point has a quadratic dependence on the mean dipole moments within the high-frequency qubit regime. Finally, we verify this critical point based on the method of semiclassical approximation.

  16. 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.

  17. 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.

  18. 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…

  19. 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.

  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. 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.

  2. 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.

  3. Discrimination and unfair treatment: relationship to cardiovascular reactivity among African American and European American women.

    PubMed

    Guyll, M; Matthews, K A; Bromberger, J T

    2001-09-01

    This study examined the relationship of cardiovascular reactivity to both interpersonal mistreatment and discrimination in a community-based sample of African American and European American women (N=363) in midlife. Subtle mistreatment related positively to diastolic blood pressure (DBP) reactivity for African American participants but not their European American counterparts. Moreover, among the African American participants, those who attributed mistreatment to racial discrimination exhibited greater average DBP reactivity. In particular, these women demonstrated greater DBP reactivity to the speech task, which bore similarities to an encounter with racial prejudice but not to a nonsocial mirror tracing task. These findings are consistent with the hypothesis that racial discrimination is a chronic stressor that can negatively impact the cardiovascular health of African Americans through pathogenic processes associated with physiologic reactivity.

  4. 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.

  5. 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.

  6. Gene Positioning

    PubMed Central

    Ferrai, Carmelo; de Castro, Inês Jesus; Lavitas, Liron; Chotalia, Mita; Pombo, Ana

    2010-01-01

    Eukaryotic gene expression is an intricate multistep process, regulated within the cell nucleus through the activation or repression of RNA synthesis, processing, cytoplasmic export, and translation into protein. The major regulators of gene expression are chromatin remodeling and transcription machineries that are locally recruited to genes. However, enzymatic activities that act on genes are not ubiquitously distributed throughout the nucleoplasm, but limited to specific and spatially defined foci that promote preferred higher-order chromatin arrangements. The positioning of genes within the nuclear landscape relative to specific functional landmarks plays an important role in gene regulation and disease. PMID:20484389

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. A Survey of Techniques for Approximate Computing

    DOE PAGES

    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

  12. Approximate probability distributions of the master equation.

    PubMed

    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 APPROXIMATE EQUATION OF STATE OF SOLIDS.

    DTIC Science & Technology

    research. By generalizing experimental data and obtaining unified relations describing the thermodynamic properties of solids, and approximate equation of state is derived which can be applied to a wide class of materials. (Author)

  14. 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.

  15. Approximation methods in gravitational-radiation theory

    NASA Astrophysics Data System (ADS)

    Will, C. M.

    1986-02-01

    The observation of gravitational-radiation damping in the binary pulsar PSR 1913+16 and the ongoing experimental search for gravitational waves of extraterrestrial origin have made the theory of gravitational radiation an active branch of classical general relativity. In calculations of gravitational radiation, approximation methods play a crucial role. The author summarizes recent developments in two areas in which approximations are important: (1) the quadrupole approximation, which determines the energy flux and the radiation reaction forces in weak-field, slow-motion, source-within-the-near-zone systems such as the binary pulsar; and (2) the normal modes of oscillation of black holes, where the Wentzel-Kramers-Brillouin approximation gives accurate estimates of the complex frequencies of the modes.

  16. A Survey of Techniques for Approximate Computing

    SciTech Connect

    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 to 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.

  17. 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.

  18. Computational aspects of pseudospectral Laguerre approximations

    NASA Technical Reports Server (NTRS)

    Funaro, Daniele

    1989-01-01

    Pseudospectral approximations in unbounded domains by Laguerre polynomials lead to ill-conditioned algorithms. Introduced are a scaling function and appropriate numerical procedures in order to limit these unpleasant phenomena.

  19. The closure approximation in the hierarchy equations.

    NASA Technical Reports Server (NTRS)

    Adomian, G.

    1971-01-01

    The expectation of the solution process in a stochastic operator equation can be obtained from averaged equations only under very special circumstances. Conditions for validity are given and the significance and validity of the approximation in widely used hierarchy methods and the ?self-consistent field' approximation in nonequilibrium statistical mechanics are clarified. The error at any level of the hierarchy can be given and can be avoided by the use of the iterative method.

  20. Approximate String Matching with Reduced Alphabet

    NASA Astrophysics Data System (ADS)

    Salmela, Leena; Tarhio, Jorma

    We present a method to speed up approximate string matching by mapping the factual alphabet to a smaller alphabet. We apply the alphabet reduction scheme to a tuned version of the approximate Boyer-Moore algorithm utilizing the Four-Russians technique. Our experiments show that the alphabet reduction makes the algorithm faster. Especially in the k-mismatch case, the new variation is faster than earlier algorithms for English data with small values of k.

  1. 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.

  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. Computing functions by approximating the input

    NASA Astrophysics Data System (ADS)

    Goldberg, Mayer

    2012-12-01

    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 output. Our approach assumes only the most rudimentary knowledge of algebra and trigonometry, and makes no use of calculus.

  4. Better position

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    The U.S. Global Positioning System (GPS) will soon become more accurate for civilian users, improving the quality of navigation and of some types of scientific research. The Clinton Administration announced March 29 that within a decade, the federal government will stop degrading the civilian GPS signal and will allow nonmilitary users access to the same clear signals that U.S. troops rely upon.Designed as dual-use system with primary use by the American military, the GPS is a constellation of 24 satellites that allows soldiers to determine their exact positions (in latitude and longitude) anywhere in the world. While the GPS is operated by the Department of Defense (DoD), scientists and adventurous civilians have been able to purchase small, portable GPS devices. However, the U.S. military has kept to itself a capability known as “selective availability” that provides a much more precise signal than is available to the public. According to the White House, that selected signal will be available to all users within 4-10 years.

  5. 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.

  6. 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

  7. The Relationship between Racial Identity and Perceived Significance of the Election of President Barack Obama among African American Mothers.

    PubMed

    Franco, Marisa; Smith-Bynum, Mia

    2016-01-01

    African American women's racial identity is a major determinant for how they interpret the world around them, yet there is little research examining how specific aspects of racial identity are linked with attitudes about an event that has been highly significant for African-Americans: the election of President Barack Obama. The current study examined the relationship between African American mothers' racial identity and their perceived significance of the election of President Barack Obama as an indicator of reduced systemic and actual racism for African Americans, using a sample of 110 African American mothers residing in a Northeastern metropolitan area. Results revealed that racial centrality and assimilation positively predicted perceived significance of President Obama's election for diminishing racism. Implications and future directions are discussed.

  8. Some African American Males' Perspectives on the Black Woman.

    ERIC Educational Resources Information Center

    Burrow, Rufus, Jr.

    1992-01-01

    Presents views of Frederick Douglass, W. E. B. Du Bois, Malcolm X, and James Hal Cone (African-American male leaders) toward African-American women in the United States. Discusses the role of African-American men in addressing and eradicating sexism in African-American churches and the African-American community. (SLD)

  9. Barriers and facilitators affecting African Americans continuation into graduate programs in nursing.

    PubMed

    Mingo, Aunderia Doreen

    2008-01-01

    The population in the United States (US) is becoming more and more diverse. With each year the minority population in the US continues to grow. In the year 2000 there were over 281 million Americans with approximately 23% of them being minorities (US Census, 2000). African-Americans accounted for 34.6 million of the population or 12.3% in the 2000 census. Yet despite their growing numbers in the general population African-American Registered Nurses (RNs) only accounted for 4.9% of the total nurse population in the 2002 National Sample Survey of RN's (Health Resources Services Administration [HRSA], 2002).

  10. Legendre-Tau approximation for functional differential equations. Part 3: Eigenvalue approximations and uniform stability

    NASA Technical Reports Server (NTRS)

    Ito, K.

    1984-01-01

    The stability and convergence properties of the Legendre-tau approximation for hereditary differential systems are analyzed. A charactristic equation is derived for the eigenvalues of the resulting approximate system. As a result of this derivation the uniform exponential stability of the solution semigroup is preserved under approximation. It is the key to obtaining the convergence of approximate solutions of the algebraic Riccati equation in trace norm.

  11. Adherence discourse among African-American women taking HAART

    PubMed Central

    Sankar, A.; Luborsky, M.; Schuman, P.; Roberts, G.

    2014-01-01

    Low adherence is the single most important challenge to controlling HIV through the use of high acting anti-retrovirals (HAART). Non-adherence poses an immediate threat to individuals who develop resistant forms of the virus as well as a public health threat if those individuals pass on treatment-resistant forms of the virus. To understand the concerns and perceptions that promote or deter adherence to antiretroviral medication by HIV-positive African-American women, we conducted in-depth interviews with 15 African-American women taking HAART. We focused on the discourse and narratives women use in talking about their adherence practice. Discourse analysis was utilized to identify and explore the sources of influence used by these women in describing their adherence practice. Roughly a third of the sample fell into each of the three self-assessed adherence categories: always adherent, mostly adherent and somewhat adherent. Among the ‘always adherent’, 80% of the sources of influence cited supported adherence, while only 48% and 47% of the authoritative sources cited by women in the ‘mostly’ and ‘somewhat’ categories supported adherence. Each self-assessed adherence group was characterized by its own distinctive discourse style. Findings suggest that adherence to HAART among African-American HIV-positive women would be improved by identifying those influences undermining adherence. Focused study of the ‘always adherent’ types is recommended. PMID:11940279

  12. 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

  13. 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.

  14. 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.

  15. MYCOBACTERIUM GENAVENSE IN AN AFRICAN PENGUIN (SPHENISCUS DEMERSUS).

    PubMed

    Krause, Kristian J; Reavill, Drury; Weldy, Scott H; Bradway, Daniel S

    2015-12-01

    A 19-yr-old female African penguin (Spheniscus demersus) presented with labored breathing and anorexia. Radiographs revealed soft-tissue density lesions in the left lung fields and fluid in the right. The penguin died during the night. Postmortem examination demonstrated multiple granulomas in the lungs and air sacs. The right coelom was filled with opaque fluid. Histopathology of the lung, liver, kidney, and spleen identified Mycobacterium as a primary disease etiology. Large numbers of acid fast-positive, rod-shaped bacteria were recognized on tissue staining. Mycobacterium genavense was detected by polymerase chain reaction (PCR) using primers specific for the species. Further confirmation of M. genavense was accomplished using PCR with universal Mycobacterium spp. primers followed by sequencing of the amplicon obtained. To our knowledge, this is the first reported case of mycobacteriosis-and specifically M. genavense -in an African penguin. This case also demonstrates the similarities of presentation between the more commonly suspected and encountered aspergillosis and mycobacteriosis.

  16. Ecological influences of sexuality on early adolescent African American females.

    PubMed

    Aronowitz, Teri; Rennells, Rachel E; Todd, Erin

    2006-01-01

    African Americans make up the greater proportion of AIDS cases in adolescent girls but little is understood about the development of sexual risk behaviors during the early adolescent years. This article will explore ecological factors influencing adolescent sexual risk behaviors. In the focus groups, which were conducted using 28 African American mothers and their early adolescent daughters, 2 major themes emerged: exposure and support systems. Mothers described the impact community had on their daughters and how monitoring and support systems worked together to control exposure. The girls detailed the different ways they were impacted by the community. Attitudes the girls adopted from their exposures resulted in risk-taking behaviors or a determination to positively impact the community. Community was shown to be the context of the acquisition of sexual knowledge and attitudes. These findings support the development of interventions to address the impact of community on the participation of sexual risk behaviors.

  17. Military social work in the South African National Defence Force.

    PubMed

    Kruger, A; Van Breda, A D

    2001-11-01

    The transformation of the South African National Defence Force has prompted a critical reassessment of the Directorate of Social Work. As a result, the directorate realized the need for a formal business plan to align the profession strategically with the core business of the military system. After completion of the business plan, the need for a unique military social work practice model was identified. Such a model should present social workers with a strategy for the achievement of the goals and objectives of the business plan. The practice model rests on two key concepts: binocular vision and practice positions. Since the onset of the transformation process in the South African National Defence Force, these two documents have reflected the changing milieu within which social work is practiced. The main concepts of these documents are presented.

  18. 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.

  19. [Return of African sleeping sickness].

    PubMed

    Stingl, Peter

    2006-09-14

    At present there is a steady rise in African sleeping sickness (trypanosomiasis) transmitted by the Tsetse fly, and which if left untreated, is fatal. Thanks to more than so years of neglect by research, our therapeutic repertoire is limited to medications with a high level of toxicity. Both WHO and international aid organizations are pushing hard for the development of new, more efficient drugs that can be readily applied in the field.

  20. 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…

  1. 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,…

  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. The Role of Race and Gender in the Mentoring Experiences and Career Success of African American Female Senior Executive Administrators in Higher Education

    ERIC Educational Resources Information Center

    Clayton, Taffye Benson

    2009-01-01

    From 1995 to 2005 education doctoral degrees conferred to African American females increased by 92%, however the increase in availability among this population for higher education administrator positions has not kept pace with the growth of African American female higher education doctoral graduates (Ryu, 2008). Such data have spurred inquiry…

  4. On uniform approximation of elliptic functions by Padé approximants

    NASA Astrophysics Data System (ADS)

    Khristoforov, Denis V.

    2009-06-01

    Diagonal Padé approximants of elliptic functions are studied. It is known that the absence of uniform convergence of such approximants is related to them having spurious poles that do not correspond to any singularities of the function being approximated. A sequence of piecewise rational functions is proposed, which is constructed from two neighbouring Padé approximants and approximates an elliptic function locally uniformly in the Stahl domain. The proof of the convergence of this sequence is based on deriving strong asymptotic formulae for the remainder function and Padé polynomials and on the analysis of the behaviour of a spurious pole. Bibliography: 23 titles.

  5. 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.

  6. Estimation of distribution algorithms with Kikuchi approximations.

    PubMed

    Santana, Roberto

    2005-01-01

    The question of finding feasible ways for estimating probability distributions is one of the main challenges for Estimation of Distribution Algorithms (EDAs). To estimate the distribution of the selected solutions, EDAs use factorizations constructed according to graphical models. The class of factorizations that can be obtained from these probability models is highly constrained. Expanding the class of factorizations that could be employed for probability approximation is a necessary step for the conception of more robust EDAs. In this paper we introduce a method for learning a more general class of probability factorizations. The method combines a reformulation of a probability approximation procedure known in statistical physics as the Kikuchi approximation of energy, with a novel approach for finding graph decompositions. We present the Markov Network Estimation of Distribution Algorithm (MN-EDA), an EDA that uses Kikuchi approximations to estimate the distribution, and Gibbs Sampling (GS) to generate new points. A systematic empirical evaluation of MN-EDA is done in comparison with different Bayesian network based EDAs. From our experiments we conclude that the algorithm can outperform other EDAs that use traditional methods of probability approximation in the optimization of functions with strong interactions among their variables.

  7. Approximation of Bivariate Functions via Smooth Extensions

    PubMed Central

    Zhang, Zhihua

    2014-01-01

    For a smooth bivariate function defined on a general domain with arbitrary shape, it is difficult to do Fourier approximation or wavelet approximation. In order to solve these problems, in this paper, we give an extension of the bivariate function on a general domain with arbitrary shape to a smooth, periodic function in the whole space or to a smooth, compactly supported function in the whole space. These smooth extensions have simple and clear representations which are determined by this bivariate function and some polynomials. After that, we expand the smooth, periodic function into a Fourier series or a periodic wavelet series or we expand the smooth, compactly supported function into a wavelet series. Since our extensions are smooth, the obtained Fourier coefficients or wavelet coefficients decay very fast. Since our extension tools are polynomials, the moment theorem shows that a lot of wavelet coefficients vanish. From this, with the help of well-known approximation theorems, using our extension methods, the Fourier approximation and the wavelet approximation of the bivariate function on the general domain with small error are obtained. PMID:24683316

  8. Effects of Economic Disruptions on Alcohol Use and Problems: Why Do African Americans Fare Worse?

    PubMed Central

    Jones-Webb, Rhonda; Karriker-Jaffe, Katherine J.; Zemore, Sarah E.; Mulia, Nina

    2016-01-01

    Objective: This study tested a model of the effects of recession-related job loss on alcohol use disorder (AUD) and examined why African Americans who lost their jobs during the 2008–2009 recession were at increased risk for AUD relative to Whites. We hypothesized that (a) job loss would be positively associated with psychological distress (i.e., higher levels of depressive symptoms) and increased drunkenness, and (b) low levels of family social support and experiences of racial stigma would exacerbate the effects of job loss on distress, especially among African Americans and Hispanics. Method: Data were drawn from the 2010 U.S. National Alcohol Survey (NAS), a cross-sectional survey of the U.S. general population. Using data from the 2010 NAS (telephone survey of 1,111 African American, 964 Hispanic, and 3,133 White adults), we conducted simultaneous path modeling in Mplus to test mediation and moderation hypotheses. Our key outcome was AUD as measured by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Results: Recession-related job loss was significantly associated with AUD through its effects on increased drunkenness, and the associations were positive for Whites, stronger for African Americans than Whites, and nonexistent for Hispanics. Job loss was associated with distress in the overall sample, and distress was positively associated with drunkenness among African Americans only, suggesting that distress is another pathway by which job loss affects AUD among African Americans. Higher levels of family social support mitigated the effects of job loss on psychological distress, and this relationship did not differ by race/ethnicity. Conclusions: During economic downturns, increased stress and heavy drinking are important pathways through which recession-related job loss can lead to greater AUD among African Americans relative to Whites. PMID:26997184

  9. A new malaria agent in African hominids.

    PubMed

    Ollomo, Benjamin; Durand, Patrick; Prugnolle, Franck; Douzery, Emmanuel; Arnathau, Céline; Nkoghe, Dieudonné; Leroy, Eric; Renaud, François

    2009-05-01

    Plasmodium falciparum is the major human malaria agent responsible for 200 to 300 million infections and one to three million deaths annually, mainly among African infants. The origin and evolution of this pathogen within the human lineage is still unresolved. A single species, P. reichenowi, which infects chimpanzees, is known to be a close sister lineage of P. falciparum. Here we report the discovery of a new Plasmodium species infecting Hominids. This new species has been isolated in two chimpanzees (Pan troglodytes) kept as pets by villagers in Gabon (Africa). Analysis of its complete mitochondrial genome (5529 nucleotides including Cyt b, Cox I and Cox III genes) reveals an older divergence of this lineage from the clade that includes P. falciparum and P. reichenowi (approximately 21+/-9 Myrs ago using Bayesian methods and considering that the divergence between P. falciparum and P. reichenowi occurred 4 to 7 million years ago as generally considered in the literature). This time frame would be congruent with the radiation of hominoids, suggesting that this Plasmodium lineage might have been present in early hominoids and that they may both have experienced a simultaneous diversification. Investigation of the nuclear genome of this new species will further the understanding of the genetic adaptations of P. falciparum to humans. The risk of transfer and emergence of this new species in humans must be now seriously considered given that it was found in two chimpanzees living in contact with humans and its close relatedness to the most virulent agent of malaria.

  10. Evolutionary history of African mongoose rabies.

    PubMed

    Van Zyl, N; Markotter, W; Nel, L H

    2010-06-01

    Two biotypes or variants of rabies virus (RABV) occur in southern Africa. These variants are respectively adapted to hosts belonging to the Canidae family (the canid variant) and hosts belonging to the Herpestidae family (the mongoose variant). Due to the distinct host adaptation and differences in epidemiology and pathogenesis, it has been hypothesized that the two variants were introduced into Africa at different times. The objective of this study was to investigate the molecular phylogeny of representative RABV isolates of the mongoose variant towards a better understanding of the origins of this group. The study was based on an analysis of the full nucleoprotein and glycoprotein gene sequences of a panel of 27 viruses. Phylogenetic analysis of this dataset confirmed extended evolutionary adaptation of isolates in specific geographic areas. The evolutionary dynamics of this virus variant was investigated using Bayesian methodology, allowing for rate variation among viral lineages. Molecular clock analysis estimated the age of the African mongoose RABV to be approximately 200 years old, which is in concurrence with literature describing rabies in mongooses since the early 1800 s.

  11. Analysing breast cancer microarrays from African Americans using shrinkage-based discriminant analysis.

    PubMed

    Pang, Herbert; Ebisu, Keita; Watanabe, Emi; Sue, Laura Y; Tong, Tiejun

    2010-10-01

    Breast cancer tumours among African Americans are usually more aggressive than those found in Caucasian populations. African-American patients with breast cancer also have higher mortality rates than Caucasian women. A better understanding of the disease aetiology of these breast cancers can help to improve and develop new methods for cancer prevention, diagnosis and treatment. The main goal of this project was to identify genes that help differentiate between oestrogen receptor-positive and -negative samples among a small group of African-American patients with breast cancer. Breast cancer microarrays from one of the largest genomic consortiums were analysed using 13 African-American and 201 Caucasian samples with oestrogen receptor status. We used a shrinkage-based classification method to identify genes that were informative in discriminating between oestrogen receptor-positive and -negative samples. Subset analysis and permutation were performed to obtain a set of genes unique to the African-American population. We identified a set of 156 probe sets, which gave a misclassification rate of 0.16 in distinguishing between oestrogen receptor-positive and -negative patients. The biological relevance of our findings was explored through literature-mining techniques and pathway mapping. An independent dataset was used to validate our findings and we found that the top ten genes mapped onto this dataset gave a misclassification rate of 0.15. The described method allows us best to utilise the information available from small sample size microarray data in the context of ethnic minorities.

  12. Validation of a shed skin corticosterone enzyme immunoassay in the African House Snake (Lamprophis fuliginosus) and its evaluation in the Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus).

    PubMed

    Berkvens, Charlene N; Hyatt, Crystal; Gilman, Christine; Pearl, David L; Barker, Ian K; Mastromonaco, Gabriela F

    2013-12-01

    This study investigates the use of an enzyme immunoassay to measure keratin glucocorticoid concentrations in reptilian shed skins. Keratin glucocorticoid concentrations were compared to fecal glucocorticoid concentrations during the period of keratin growth in the African House Snake (Lamprophis fuliginosus) and the Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus). Biochemical validation was performed for the shed skin and fecal corticosterone enzyme immunoassays in the African House Snake. Biological and physiological validations were attempted in the African House Snake. A statistically significant positive association was detected between shed skin corticosterone and the mean fecal corticosterone metabolites from 3 weeks before to 1 week after the previous ecdysis in the African House Snake. A statistically significant difference was not detected between the shed skin corticosterone concentrations of the minimally handled control and the weekly handled (or experimentally stressed) African House Snakes. Adrenocorticotropic hormone stimulation did not result in the physiological validation anticipated for shed skin corticosterone concentrations in the African House Snake.

  13. African-Centered Education: An Approach to Schooling for Social Justice for African American Students

    ERIC Educational Resources Information Center

    Marks, Jay B.; Tonso, Karen L.

    2006-01-01

    This essay argues that offering African American students an African-centered education is one way to promote social justice in public education. We begin with a summary of the inadequate educations offered to many African American students, and then use philosophical interpretations of equal educational opportunity to delineate the requirements…

  14. Investigating Instructional Practices of an African American Male Mathematics Teacher with Underachieving African American Male Students

    ERIC Educational Resources Information Center

    Muhammad, Rhonda K.

    2012-01-01

    This qualitative study examined the instructional practices of an experienced African American mathematics teacher to determine his perceived capabilities in augmenting academic proficiency for his African American male students. Provided in this descriptive case study are the lived experiences of an African American male teacher working to move…

  15. Fast wavelet based sparse approximate inverse preconditioner

    SciTech Connect

    Wan, W.L.

    1996-12-31

    Incomplete LU factorization is a robust preconditioner for both general and PDE problems but unfortunately not easy to parallelize. Recent study of Huckle and Grote and Chow and Saad showed that sparse approximate inverse could be a potential alternative while readily parallelizable. However, for special class of matrix A that comes from elliptic PDE problems, their preconditioners are not optimal in the sense that independent of mesh size. A reason may be that no good sparse approximate inverse exists for the dense inverse matrix. Our observation is that for this kind of matrices, its inverse entries typically have piecewise smooth changes. We can take advantage of this fact and use wavelet compression techniques to construct a better sparse approximate inverse preconditioner. We shall show numerically that our approach is effective for this kind of matrices.

  16. The Cell Cycle Switch Computes Approximate Majority

    NASA Astrophysics Data System (ADS)

    Cardelli, Luca; Csikász-Nagy, Attila

    2012-09-01

    Both computational and biological systems have to make decisions about switching from one state to another. The `Approximate Majority' computational algorithm provides the asymptotically fastest way to reach a common decision by all members of a population between two possible outcomes, where the decision approximately matches the initial relative majority. The network that regulates the mitotic entry of the cell-cycle in eukaryotes also makes a decision before it induces early mitotic processes. Here we show that the switch from inactive to active forms of the mitosis promoting Cyclin Dependent Kinases is driven by a system that is related to both the structure and the dynamics of the Approximate Majority computation. We investigate the behavior of these two switches by deterministic, stochastic and probabilistic methods and show that the steady states and temporal dynamics of the two systems are similar and they are exchangeable as components of oscillatory networks.

  17. Separable approximations of two-body interactions

    NASA Astrophysics Data System (ADS)

    Haidenbauer, J.; Plessas, W.

    1983-01-01

    We perform a critical discussion of the efficiency of the Ernst-Shakin-Thaler method for a separable approximation of arbitrary two-body interactions by a careful examination of separable 3S1-3D1 N-N potentials that were constructed via this method by Pieper. Not only the on-shell properties of these potentials are considered, but also a comparison is made of their off-shell characteristics relative to the Reid soft-core potential. We point out a peculiarity in Pieper's application of the Ernst-Shakin-Thaler method, which leads to a resonant-like behavior of his potential 3SD1D. It is indicated where care has to be taken in order to circumvent drawbacks inherent in the Ernst-Shakin-Thaler separable approximation scheme. NUCLEAR REACTIONS Critical discussion of the Ernst-Shakin-Thaler separable approximation method. Pieper's separable N-N potentials examined on shell and off shell.

  18. Eight-moment approximation solar wind models

    NASA Technical Reports Server (NTRS)

    Olsen, Espen Lyngdal; Leer, Egil

    1995-01-01

    Heat conduction from the corona is important in the solar wind energy budget. Until now all hydrodynamic solar wind models have been using the collisionally dominated gas approximation for the heat conductive flux. Observations of the solar wind show particle distribution functions which deviate significantly from a Maxwellian, and it is clear that the solar wind plasma is far from collisionally dominated. We have developed a numerical model for the solar wind which solves the full equation for the heat conductive flux together with the conservation equations for mass, momentum, and energy. The equations are obtained by taking moments of the Boltzmann equation, using an 8-moment approximation for the distribution function. For low-density solar winds the 8-moment approximation models give results which differ significantly from the results obtained in models assuming the gas to be collisionally dominated. The two models give more or less the same results in high density solar winds.

  19. Approximate solutions of the hyperbolic Kepler equation

    NASA Astrophysics Data System (ADS)

    Avendano, Martín; Martín-Molina, Verónica; Ortigas-Galindo, Jorge

    2015-12-01

    We provide an approximate zero widetilde{S}(g,L) for the hyperbolic Kepler's equation S-g {{arcsinh}}(S)-L=0 for gin (0,1) and Lin [0,∞ ). We prove, by using Smale's α -theory, that Newton's method starting at our approximate zero produces a sequence that converges to the actual solution S( g, L) at quadratic speed, i.e. if S_n is the value obtained after n iterations, then |S_n-S|≤ 0.5^{2^n-1}|widetilde{S}-S|. The approximate zero widetilde{S}(g,L) is a piecewise-defined function involving several linear expressions and one with cubic and square roots. In bounded regions of (0,1) × [0,∞ ) that exclude a small neighborhood of g=1, L=0, we also provide a method to construct simpler starters involving only constants.

  20. Approximation methods in gravitational-radiation theory

    NASA Technical Reports Server (NTRS)

    Will, C. M.

    1986-01-01

    The observation of gravitational-radiation damping in the binary pulsar PSR 1913 + 16 and the ongoing experimental search for gravitational waves of extraterrestrial origin have made the theory of gravitational radiation an active branch of classical general relativity. In calculations of gravitational radiation, approximation methods play a crucial role. Recent developments are summarized in two areas in which approximations are important: (a) the quadrupole approxiamtion, which determines the energy flux and the radiation reaction forces in weak-field, slow-motion, source-within-the-near-zone systems such as the binary pulsar; and (b) the normal modes of oscillation of black holes, where the Wentzel-Kramers-Brillouin approximation gives accurate estimates of the complex frequencies of the modes.

  1. 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...

  2. 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...

  3. 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.

  4. African American girls and the challenges ahead.

    PubMed

    Rozie-Battle, Judith L

    2002-01-01

    The research on the psychosocial development of African American girls is limited. Information that is available focuses on teen pregnancy and health issues such as nutrition and physical activity. African American girls are facing challenges, including poverty, crime, poor self-esteem, and peer pressure. Despite some of the negative characteristics attributed to African American girls, many are achieving some success. Policy makers and service providers need to recognize the resiliency and unique needs of African American girls and develop services that ensure their needs are being fully met.

  5. Rhinoplasty in the African-American patient.

    PubMed

    Rohrich, Rod J; Muzaffar, Arshad R

    2003-03-01

    Because of the increasing popularity of rhinoplasty in the African-American patient, we delineate how a rhinoplasty surgeon can perform this challenging technique to obtain uniform and consistent results. First, we address how one can appreciate and analyze the various aesthetic concepts of beauty and the unique anatomic characteristics of the African-American nose. Second, we present a pragmatic, systematic analysis of the African-American nose. Last, we describe the techniques consistently used to modify the African-American nose while achieving or maintaining facial harmony using the open approach to rhinoplasty. Specific case analyses are presented to demonstrate utilization of the technique.

  6. The African diaspora: history, adaptation and health.

    PubMed

    Rotimi, Charles N; Tekola-Ayele, Fasil; Baker, Jennifer L; Shriner, Daniel

    2016-12-01

    The trans-Atlantic slave trade brought millions of Africans to the New World. Advances in genomics are providing novel insights into the history and health of Africans and the diasporan populations. Recent examples reviewed here include the unraveling of substantial hunter-gatherer and 'Eurasian' admixtures across sub-Saharan Africa, expanding our understanding of ancestral African genetics; the global ubiquity of mixed ancestry; the revealing of African ancestry in Latin Americans that likely derived from the slave trade; and understanding of the ancestral backgrounds of APOL1 and LPL found to influence kidney disease and lipid levels, respectively, providing specific insights into disease etiology and health disparities.

  7. Gentle Africanized bees on an oceanic island.

    PubMed

    Rivera-Marchand, Bert; Oskay, Devrim; Giray, Tugrul

    2012-11-01

    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.

  8. 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

  9. Exponential Approximations Using Fourier Series Partial Sums

    NASA Technical Reports Server (NTRS)

    Banerjee, Nana S.; Geer, James F.

    1997-01-01

    The problem of accurately reconstructing a piece-wise smooth, 2(pi)-periodic function f and its first few derivatives, given only a truncated Fourier series representation of f, is studied and solved. The reconstruction process is divided into two steps. In the first step, the first 2N + 1 Fourier coefficients of f are used to approximate the locations and magnitudes of the discontinuities in f and its first M derivatives. This is accomplished by first finding initial estimates of these quantities based on certain properties of Gibbs phenomenon, and then refining these estimates by fitting the asymptotic form of the Fourier coefficients to the given coefficients using a least-squares approach. It is conjectured that the locations of the singularities are approximated to within O(N(sup -M-2), and the associated jump of the k(sup th) derivative of f is approximated to within O(N(sup -M-l+k), as N approaches infinity, and the method is robust. These estimates are then used with a class of singular basis functions, which have certain 'built-in' singularities, to construct a new sequence of approximations to f. Each of these new approximations is the sum of a piecewise smooth function and a new Fourier series partial sum. When N is proportional to M, it is shown that these new approximations, and their derivatives, converge exponentially in the maximum norm to f, and its corresponding derivatives, except in the union of a finite number of small open intervals containing the points of singularity of f. The total measure of these intervals decreases exponentially to zero as M approaches infinity. The technique is illustrated with several examples.

  10. 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.

  11. Space science education in the african continent

    NASA Astrophysics Data System (ADS)

    Aseno, J. O.

    Through measurement and interpretation of the spectral, spatial and temporal variations in electromagnetic emissions and reflections from the Earth's surface, important information related to natural resources can be acquired. Furthermore, satellite technology has greatly improved the communication and positioning techniques world-wide. Consequently, space science now provides valuable and timely information about natural resources, which has become a major factor in sustainable development. The realization of the full potential of space science in the context of development in Africa requires adequate education and training in order to facilitate project formulation, planning, management and implementation. This, in turn, would lead to the formulation and adoption of national space science policies based on user needs and addressing both the short and long-term needs of a particular country. Space science education in Africa needs to address issues like (i) provision of programme, (ii) integration of the proposed techniques within the existing infrastructure, and (iii) training in Remote Sensing, Global Positioning System, Geographic Information System and other space science techniques, in order to ensure the successful implementation of space science projects within the continent. In this context, African universities ought to play a major role in space science training, research, consultancy and publication. Through international co-operation, it is possible to develop and support national, regional and international training programmes and international scientific exchange in Africa.

  12. Very fast approximate reconstruction of MR images.

    PubMed

    Angelidis, P A

    1998-11-01

    The ultra fast Fourier transform (UFFT) provides the means for a very fast computation of a magnetic resonance (MR) image, because it is implemented using only additions and no multiplications at all. It achieves this by approximating the complex exponential functions involved in the Fourier transform (FT) sum with computationally simpler periodic functions. This approximation introduces erroneous spectrum peaks of small magnitude. We examine the performance of this transform in some typical MRI signals. The results show that this transform can very quickly provide an MR image. It is proposed to be used as a replacement of the classically used FFT whenever a fast general overview of an image is required.

  13. Congruence Approximations for Entrophy Endowed Hyperbolic Systems

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.; Saini, Subhash (Technical Monitor)

    1998-01-01

    Building upon the standard symmetrization theory for hyperbolic systems of conservation laws, congruence properties of the symmetrized system are explored. These congruence properties suggest variants of several stabilized numerical discretization procedures for hyperbolic equations (upwind finite-volume, Galerkin least-squares, discontinuous Galerkin) that benefit computationally from congruence approximation. Specifically, it becomes straightforward to construct the spatial discretization and Jacobian linearization for these schemes (given a small amount of derivative information) for possible use in Newton's method, discrete optimization, homotopy algorithms, etc. Some examples will be given for the compressible Euler equations and the nonrelativistic MHD equations using linear and quadratic spatial approximation.

  14. Bronchopulmonary segments approximation using anatomical atlas

    NASA Astrophysics Data System (ADS)

    Busayarat, Sata; Zrimec, Tatjana

    2007-03-01

    Bronchopulmonary segments are valuable as they give more accurate localization than lung lobes. Traditionally, determining the segments requires segmentation and identification of segmental bronchi, which, in turn, require volumetric imaging data. In this paper, we present a method for approximating the bronchopulmonary segments for sparse data by effectively using an anatomical atlas. The atlas is constructed from a volumetric data and contains accurate information about bronchopulmonary segments. A new ray-tracing based image registration is used for transferring the information from the atlas to a query image. Results show that the method is able to approximate the segments on sparse HRCT data with slice gap up to 25 millimeters.

  15. Approximate learning algorithm in Boltzmann machines.

    PubMed

    Yasuda, Muneki; Tanaka, Kazuyuki

    2009-11-01

    Boltzmann machines can be regarded as Markov random fields. For binary cases, they are equivalent to the Ising spin model in statistical mechanics. Learning systems in Boltzmann machines are one of the NP-hard problems. Thus, in general we have to use approximate methods to construct practical learning algorithms in this context. In this letter, we propose new and practical learning algorithms for Boltzmann machines by using the belief propagation algorithm and the linear response approximation, which are often referred as advanced mean field methods. Finally, we show the validity of our algorithm using numerical experiments.

  16. [Formalized consensus: clinical practice recommendations for the management of the migraine in African adult patients].

    PubMed

    Ahmed, Mahmoud Ait Kaci; Haddad, Monia; Kouassi, Beugré; Ouhabi, Hamid; Serrie, Alain

    2016-01-01

    Migraine is a primary headache disorder (according to the latest International Headache Society criteria) affecting approximately 8% of African population. Women are more often affected than men and attacks usually occur before the age of 40 years Although some treatments, hygienic-dietary measures and other non-pharmacological methods can reduce the intensity and frequency of attacks, medicinal treatment of migraine attack is often necessary. Availability of treatments and access to care differ in Africa and led to the implementation of the first expert consensus recommendations for the management of the migraine in african adult patients. This multinational collaborative study is intended for health practitioners. It aims to provide 16 simple, evidence-based recommendations and is adapted to african medical practice.

  17. Multi-point quasi-rational approximants for the modified Bessel function I1(x)

    NASA Astrophysics Data System (ADS)

    Martin, P.; Olivares, J.; Cortés-Vega, L.; Sotomayor, A.

    2016-08-01

    Approximants for the modified Bessel function I1(x) has been found using the multi-point quasi-rational technique. The approximations here determined has good accuracy for any positive value of the variable, and it seems to be adequate for most of the works where this function are used. Furthermore, the approximants are simple to calculate numerically in a direct way or using any usual MAPLE or MATLAB software.

  18. Understanding the Role of Clergy in African American Organ and Tissue Donation Decision-Making

    PubMed Central

    Jacob Arriola, Kimberly R.; Perryman, Jennie P.; Doldren, Michelle A.; Warren, Carmen M.; Robinson, Dana H. Z.

    2012-01-01

    Objectives To describe and understand the attitudes, beliefs, and experiences towards organ and tissue donation among African American clergy in Atlanta, Georgia, USA. The secondary objective is to understand what messages clergy are providing to their parishioners relative to organ and tissue donation, and what their perceived role is in donation education. Design A qualitative study in which African American clergy (n = 26) participated in four focus groups. Results African American clergy, though generally supportive of organ and tissue donation in principle, have serious reservations about donation due to perceived inequalities in the donation and transplantation system. The clergy did not personally hold religious concerns about donation, but expressed that these concerns were a major barrier to donation among their parishioners. None of the clergy knew the written position that their religion took on donation; they acknowledged the need for more education for them and their parishioners on this topic. They also felt that as religious leaders, they could play an important role in promoting organ and tissue donation among African American parishioners. Conclusions African American clergy and religious leaders may play an important role towards improving willingness to donate among African American parishioners, but more education and advocacy is needed to prepare them for this role. PMID:17978944

  19. 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.

  20. Approximate model for laser ablation of carbon

    NASA Astrophysics Data System (ADS)

    Shusser, Michael

    2010-08-01

    The paper presents an approximate kinetic theory model of ablation of carbon by a nanosecond laser pulse. The model approximates the process as sublimation and combines conduction heat transfer in the target with the gas dynamics of the ablated plume which are coupled through the boundary conditions at the interface. The ablated mass flux and the temperature of the ablating material are obtained from the assumption that the ablation rate is restricted by the kinetic theory limitation on the maximum mass flux that can be attained in a phase-change process. To account for non-uniform distribution of the laser intensity while keeping the calculation simple the quasi-one-dimensional approximation is used in both gas and solid phases. The results are compared with the predictions of the exact axisymmetric model that uses the conservation relations at the interface derived from the momentum solution of the Boltzmann equation for arbitrary strong evaporation. It is seen that the simpler approximate model provides good accuracy.