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Sample records for african approximate position

  1. 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.…

  2. 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…

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

    ERIC Educational Resources Information Center

    Parsons, Eileen R. Carlton

    2008-01-01

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

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

    PubMed

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

    2011-01-01

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

  5. Experiences of HIV-positive African-American and African Caribbean childbearing women: a qualitative study.

    PubMed

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

    2012-07-01

    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.

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

    ERIC Educational Resources Information Center

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

    2003-01-01

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

  7. 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...

  8. 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.

  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. Compensation of optode sensitivity and position errors in diffuse optical tomography using the approximation error approach.

    PubMed

    Mozumder, Meghdoot; Tarvainen, Tanja; Arridge, Simon R; Kaipio, Jari; Kolehmainen, Ville

    2013-01-01

    Diffuse optical tomography is highly sensitive to measurement and modeling errors. Errors in the source and detector coupling and positions can cause significant artifacts in the reconstructed images. Recently the approximation error theory has been proposed to handle modeling errors. In this article, we investigate the feasibility of the approximation error approach to compensate for modeling errors due to inaccurately known optode locations and coupling coefficients. The approach is evaluated with simulations. The results show that the approximation error method can be used to recover from artifacts in reconstructed images due to optode coupling and position errors.

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

    PubMed Central

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

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Pope, Myron L.; Moore, Cynthia

    2004-01-01

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

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

    ERIC Educational Resources Information Center

    Gamble, Erica D.

    2011-01-01

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

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  19. 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…

  20. 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…

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

    NASA Astrophysics Data System (ADS)

    Schneider, Peter; Sluse, Dominique

    2014-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    ERIC Educational Resources Information Center

    Blackstone, Tondelaya K.

    2011-01-01

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

  7. Automated facial recognition and candidate list rank change of computer generated facial approximations generated with multiple eye orb positions.

    PubMed

    Parks, Connie L; Monson, Keith L

    2016-09-01

    Expanding on research previously reported by the authors, this study further examines the recognizability of ReFace facial approximations generated with the following eye orb positions: (i) centrally within the bony eye socket, (ii) 1.0mm superior and 2.0mm lateral relative to center, and (iii) 1.0mm superior and 2.5mm lateral relative to center. Overall, 81% of the test subjects' approximation ranks improved with the use of either of the two supero-lateral eye orbs. Highly significant performance differences (p<0.01) were observed between the approximations with centrally positioned eye orbs (i) and approximations with the eye orbs placed in the supero-laterally positions (ii and iii). Noteworthy was the observation that in all cases when the best rank for an approximation was obtained with the eye orbs in position (iii), the second best rank was achieved with the eye orbs in position (ii). A similar pattern was also observed when the best rank was obtained with the eye orbs in position (ii), with 60% of the second best ranks observed in position (iii). It is argued, therefore, that an approximation constructed with the eye orbs placed in either of the two supero-lateral positions may be more effective and operationally informative than centrally positioned orbs. PMID:27416268

  8. 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…

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

    ERIC Educational Resources Information Center

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

    2003-01-01

    Positive individual and social behaviors were assessed among male gang members and males involved in community-based organizations aimed at promoting positive youth development. Correlations of attribute scores were more often significant for the gang than for the nongang youth. Approximately one-quarter of the gang youth had total positive…

  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. PMID:25844575

  11. "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.

  12. A Randomized Controlled Trial of Positive-Affect Intervention and Medication Adherence in Hypertensive African Americans

    PubMed Central

    Ogedegbe, Gbenga O.; Boutin-Foster, Carla; Wells, Martin T.; Allegrante, John P.; Isen, Alice M.; Jobe, Jared B.; Charlson, Mary E.

    2015-01-01

    Background Poor adherence explains poor blood pressure (BP) control; however African Americans suffer worse hypertension-related outcomes. Methods This randomized controlled trial evaluated whether a patient education intervention enhanced with positive-affect induction and self-affirmation (PA) was more effective than patient education (PE) alone in improving medication adherence and BP reduction among 256 hypertensive African Americans followed up in 2 primary care practices. Patients in both groups received a culturally tailored hypertension self-management workbook, a behavioral contract, and bimonthly telephone calls designed to help them overcome barriers to medication adherence. Also, patients in the PA group received small gifts and bimonthly telephone calls to help them incorporate positive thoughts into their daily routine and foster self-affirmation. The main outcome measures were medication adherence (assessed with electronic pill monitors) and within-patient change in BP from baseline to 12 months. Results The baseline characteristics were similar in both groups: the mean BP was 137/82 mm Hg; 36% of the patients had diabetes; 11% had stroke; and 3% had chronic kidney disease. Based on the intention-to-treat principle, medication adherence at 12 months was higher in the PA group than in the PE group (42% vs 36%, respectively; P =.049). The within-group reduction in systolic BP (2.14 mm Hg vs 2.18 mm Hg; P =.98) and diastolic BP (−1.59 mm Hg vs −0.78 mm Hg; P=.45) for the PA group and PE group, respectively, was not significant. Conclusions A PE intervention enhanced with PA led to significantly higher medication adherence compared with PE alone in hypertensive African Americans. Future studies should assess the cost-effectiveness of integrating such interventions into primary care. Trial Registration clinicaltrials.gov Identifier: NCT00227175 PMID:22269592

  13. 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

  14. Positioning toward Mathematics and Science Learning: An Examination of Factors Affecting Low-Income, African American Girls

    ERIC Educational Resources Information Center

    Baratelli, Adriana; West-Olatunji, Cirecie; Pringle, Rose; Adams, Thomasenia; Shure, Lauren

    2007-01-01

    (Purpose) The purpose of this study was to investigate the positionality of low income, African American school girls toward mathematics and science learning as they transition from elementary to middle school. The researchers sought to examine how culture, class and gender affected the girls' positioning in terms of mathematics and science, as…

  15. 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

  16. 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

  17. 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.

  18. Neuropsychological functioning in HIV-positive African-American women with a history of drug use.

    PubMed Central

    Mason, K. I.; Campbell, A.; Hawkins, P.; Madhere, S.; Johnson, K.; Takushi-Chinen, R.

    1998-01-01

    This preliminary investigation examined neuropsychological performance in a sample of human immunodeficiency virus (HIV)-positive and HIV-negative African-American women with a history of drug use. The study population was comprised of 10 HIV-negative, 9 asymptomatic HIV-positive, 13 symptomatic HIV-positive, and 10 acquired immunodeficiency virus (AIDS) patients. A neuropsychological battery designed to assess attention, psychomotor processing, verbal memory, and visual memory was administered to participants. No evidence of HIV-related cognitive impairment was found in patients in the early stages of HIV infection. Multivariate analyses of variance revealed significant deficits in psychomotor processing and verbal recall in persons with AIDS. These individuals showed greater difficulty in tasks requiring maintained attention and performed poorly on measures of immediate and delayed verbal recall. In contrast, HIV status was not related to visual memory, verbal recognition, or the number of errors made during a verbal recall task. The pattern of cognitive deficits observed in persons with AIDS resembles that commonly associated with subcortical pathology. The cognitive deficits observed were not related to depression or recentness of drug use. PMID:9828581

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  20. "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…

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

    ERIC Educational Resources Information Center

    Hamm, Jill V.

    2001-01-01

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

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

    PubMed

    Brinkley-Rubinstein, Lauren; Turner, William L

    2013-08-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed

    Weber, Valéry; Daul, Claude; Challacombe, Matt

    2006-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Weber, Valéry; Daul, Claude; Challacombe, Matt

    2006-06-01

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

  6. 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.

  7. 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.

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

    PubMed Central

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

    2015-01-01

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

  9. Mutations associated with occult hepatitis B in HIV-positive South Africans.

    PubMed

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

    2015-03-01

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

  10. 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.

  11. 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.

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

    PubMed

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

    2016-07-01

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

  13. 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…

  14. 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…

  15. Alcohol Consumption and Positive Study Practices among African American College Students

    ERIC Educational Resources Information Center

    dePyssler, Bruce; Williams, Valerie S. L.; Windle, Michael

    2005-01-01

    This investigation focused on the relation between college student drinking behavior and study skills, behaviors, habits, and attitudes among undergraduate students at a predominantly African American university. Students (N = 492) were administered a multimedia alcohol survey with an embedded measure of study practices. The negative and generally…

  16. 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…

  17. 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…

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

    PubMed Central

    2012-01-01

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

  19. 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.

  20. 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.

  1. 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.

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

    PubMed

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

    2015-07-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-08-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-08-01

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

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

    PubMed

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

    2016-04-15

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

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

    PubMed Central

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

    2016-01-01

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

  10. The right of patients to have access to their medical records: the position in South African law.

    PubMed

    de Klerk, A

    1993-01-01

    In this article an investigation is undertaken into the right in South African law of a patient to have access to medical records concerning himself or herself, and the ownership of medical records in South African law is also discussed. It is argued that record accessibility by patients is to be favoured. The author is of the opinion that the South African legislature should consider legislation in this regard.

  11. 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…

  12. 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…

  13. 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…

  14. 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.

  15. False Positivity of Non-Targeted Infections in Malaria Rapid Diagnostic Tests: The Case of Human African Trypanosomiasis

    PubMed Central

    Gillet, Philippe; Mumba Ngoyi, Dieudonné; Lukuka, Albert; Kande, Viktor; Atua, Benjamin; van Griensven, Johan; Muyembe, Jean-Jacques; Jacobs, Jan; Lejon, Veerle

    2013-01-01

    Background In endemic settings, diagnosis of malaria increasingly relies on the use of rapid diagnostic tests (RDTs). False positivity of such RDTs is poorly documented, although it is especially relevant in those infections that resemble malaria, such as human African trypanosomiasis (HAT). We therefore examined specificity of malaria RDT products among patients infected with Trypanosoma brucei gambiense. Methodology/Principal Findings Blood samples of 117 HAT patients and 117 matched non-HAT controls were prospectively collected in the Democratic Republic of the Congo. Reference malaria diagnosis was based on real-time PCR. Ten commonly used malaria RDT products were assessed including three two-band and seven three-band products, targeting HRP-2, Pf-pLDH and/or pan-pLDH antigens. Rheumatoid factor was determined in PCR negative subjects. Specificity of the 10 malaria RDT products varied between 79.5 and 100% in HAT-negative controls and between 11.3 and 98.8% in HAT patients. For seven RDT products, specificity was significantly lower in HAT patients compared to controls. False positive reactions in HAT were mainly observed for pan-pLDH test lines (specificities between 13.8 and 97.5%), but also occurred frequently for the HRP-2 test line (specificities between 67.9 and 98.8%). The Pf-pLDH test line was not affected by false-positive lines in HAT patients (specificities between 97.5 and 100%). False positivity was not associated to rheumatoid factor, detected in 7.6% of controls and 1.2% of HAT patients. Conclusions/Significance Specificity of some malaria RDT products in HAT was surprisingly low, and constitutes a risk for misdiagnosis of a fatal but treatable infection. Our results show the importance to assess RDT specificity in non-targeted infections when evaluating diagnostic tests. PMID:23638201

  16. Factors Affecting Disclosure in South African HIV-Positive Pregnant Women

    PubMed Central

    Forsyth, Brian W.C.; Visser, Maretha J; Sikkema, Kathleen J.; Neufeld, Sharon; Jeffery, Bridget

    2008-01-01

    Abstract To provide understanding of social and psychological factors that affect disclosure of HIV status among women diagnosed HIV-positive in pregnancy, 438 HIV positive women attending antenatal clinics in Pretoria, South Africa were invited to participate in a longitudinal study. A total of 293 (62%) women were enrolled from June 2003 to December 2004. Questionnaires assessing sociodemographics and psychological measures were administered during pregnancy and at 3 months postdelivery. At enrollment, 59% had disclosed to their partners and 42% to others. This rose to 67% and 59%, respectively, by follow-up. Logistic regression analysis identified being married (adjusted odds Ratio [AOR] 2.32; 95% confidence interval [CI] 1.20–4.47), prior discussion about testing (AOR 4.19; CI 2.34–7.49), having a partner with tertiary education (AOR 2.76; CI 1.29–5.88) and less experience of violence (AOR 0.48; CI 0.24–0.97) as factors associated with having disclosed to partners prior to enrollment. Better housing (AOR 1.26; CI 1.06–1.49), less financial dependence on partners (AOR 0.46; CI 0.25–0.85), and knowing someone with HIV (AOR 2.13; CI 1.20–3.76) were associated with prior disclosure to others. Increased levels of stigma at baseline decreased the likelihood of disclosure to partners postenrollment (AOR 0.91; CI 0.84–0.98) and increased levels of avoidant coping decreased subsequent disclosure to others (AOR 0.84; CI 0.72–0.97). These results provide understanding of disclosure for women diagnosed as HIV positive in pregnancy, and identify variables that could be used to screen for women who require help. PMID:19025485

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

    ERIC Educational Resources Information Center

    Kynard, Carmen

    2008-01-01

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

  18. 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…

  19. 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 (

  20. Sequence analyses of the distal-less homeobox gene family in East African cichlid fishes reveal signatures of positive selection

    PubMed Central

    2013-01-01

    Background Gen(om)e duplication events are hypothesized as key mechanisms underlying the origin of phenotypic diversity and evolutionary innovation. The diverse and species-rich lineage of teleost fishes is a renowned example of this scenario, because of the fish-specific genome duplication. Gene families, generated by this and other gene duplication events, have been previously found to play a role in the evolution and development of innovations in cichlid fishes - a prime model system to study the genetic basis of rapid speciation, adaptation and evolutionary innovation. The distal-less homeobox genes are particularly interesting candidate genes for evolutionary novelties, such as the pharyngeal jaw apparatus and the anal fin egg-spots. Here we study the dlx repertoire in 23 East African cichlid fishes to determine the rate of evolution and the signatures of selection pressure. Results Four intact dlx clusters were retrieved from cichlid draft genomes. Phylogenetic analyses of these eight dlx loci in ten teleost species, followed by an in-depth analysis of 23 East African cichlid species, show that there is disparity in the rates of evolution of the dlx paralogs. Dlx3a and dlx4b are the fastest evolving dlx genes, while dlx1a and dlx6a evolved more slowly. Subsequent analyses of the nonsynonymous-synonymous substitution rate ratios indicate that dlx3b, dlx4a and dlx5a evolved under purifying selection, while signs of positive selection were found for dlx1a, dlx2a, dlx3a and dlx4b. Conclusions Our results indicate that the dlx repertoire of teleost fishes and cichlid fishes in particular, is shaped by differential selection pressures and rates of evolution after gene duplication. Although the divergence of the dlx paralogs are putative signs of new or altered functions, comparisons with available expression patterns indicate that the three dlx loci under strong purifying selection, dlx3b, dlx4a and dlx5a, are transcribed at high levels in the cichlids

  1. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    ERIC Educational Resources Information Center

    Obiakor, Festus E.

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

  4. 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…

  5. 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.

  6. 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.

  7. 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

  8. 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. PMID:25903505

  9. 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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  11. 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

  12. 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…

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

    PubMed

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

    2016-09-01

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

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

    PubMed Central

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

    2016-01-01

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

  15. The Role of Mediators in the Indirect Effects of Religiosity on Therapeutic Compliance in African Migrant HIV-Positive Patients.

    PubMed

    Mambet Doue, Constance; Roussiau, Nicolas

    2016-12-01

    This research investigates the indirect effects of religiosity (practice and belief) on therapeutic compliance in 81 HIV-positive patients who are migrants from sub-Saharan Africa (23 men and 58 women). Using analyses of mediation and standard multiple regression, including a resampling procedure by bootstrapping, the role of these mediators (magical-religious beliefs and nonuse of toxic substances) was tested. The results show that, through magical-religious beliefs, religiosity has a negative indirect effect, while with the nonuse of toxic substances, religious practice has a positive indirect effect. Beyond religiosity, the role of mediators is highlighted in the interaction with therapeutic compliance. PMID:26531838

  16. 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…

  17. 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

  18. 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.

  19. 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.

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

    PubMed Central

    Kedda, M. A.; Stevens, G.; Manga, P.; Viljoen, C.; Jenkins, T.; Ramsay, M.

    1994-01-01

    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 "ty-pos OCA" 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 "normal" chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8198130

  2. 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.

  3. Genetic position of Andalusians from Huelva in relation to other European and North African populations: a study based on GM and KM allotypes.

    PubMed

    Calderón, R; Ambrosio, B; Guitard, E; González-Martín, A; Aresti, U; Dugoujon, J M

    2006-12-01

    An understanding of population relationships in the Mediterranean region is crucial to the reconstruction of recent human evolution. Andalusia, the most southern region of Spain, has been continuously and densely occupied since ancient times and has a rich history of contacts with many different Mediterranean populations. Thus, to understand the Mediterranean peopling process, investigators should analyze the population relationships between the Iberian peninsula and northern Africa based on an assessment of genetic diversity that takes Andalusia into consideration. The aim of this study was to address the extent of genetic variation in the Iberian peninsula between its geographic extremes (Huelva and the Basque area) and to explain the intensity of the phylogenetic relationships between Andalusians and other neighboring populations, such as those from North Africa. We present, for the first time, results on allotype markers (GM and KM) of human immunoglobulins in the Andalusian population from Huelva. The most frequent GM haplotypes in Andalusia correspond to those that are also the most common in Europe. A sub-Saharan haplotype was found at a relatively high frequency compared to other Iberian samples, and a North Asian marker did not reach polymorphic frequencies in the study sample. A hierarchical cluster analysis based on the first two principal components (94.1% of the total genetic variance) revealed an interesting geographic structure for the 49 populations selected from the literature. The Huelva sample showed a central position in the multivariate space--despite being geographically located at one of the extremes of the Mediterranean basin--and clustered with most Western European populations. Western Europe and Eastern Europe (the latter group paradoxically including Italy and the major islands of the western Mediterranean) were differentiated. North African populations were grouped in two clusters that did not separate either Arabs and Berbers or their

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

    ERIC Educational Resources Information Center

    Jones, Clara B.; Palmer, Julie K.

    2004-01-01

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

  5. 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,…

  6. African Centered Knowledge: A British Perspective.

    ERIC Educational Resources Information Center

    Christian, Mark

    2001-01-01

    Considers the impact of African centered knowledge within the United Kingdom. Recent development of African Diaspora studies has forged links between various black Atlantic communities. The United Kingdom has experienced positive grassroots community response to the work of noted African centered scholars, yet within the British academy,…

  7. 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…

  8. Phosphate-haemoglobin interaction. The primary structure of the haemoglobin of the African elephant (Loxodonta africana, Proboscidea): asparagine in position 2 of the beta-chain.

    PubMed

    Braunitzer, G; Stangl, A; Schrank, B; Krombach, C; Wiesner, H

    1984-07-01

    The primary structure of the haemoglobin of the African Elephant (Loxodonta africana) is reported. The sequence was determined by means of a sequenator. The haemoglobin differs in 26 amino acids in the alpha-chains and in 27 in the beta-chains from that of adult human haemoglobin. The haemoglobin of the African Elephant, like that of the Indian Elephant and Ilama, has only 5 binding sites for polyphosphate. This finding explains the low p(O2)50 value in whole blood as a result of the lower 2,3-bisphosphoglycerate-haemoglobin interaction. This is discussed in relation to aspects of respiratory physiology; some points are also of interest with regard to the Second Punic War and Hannibal's crossing of the Alps.

  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. African and African Caribbean users' perceptions of inpatient services.

    PubMed

    Secker, J; Harding, C

    2002-04-01

    It has been suggested that well-documented differences in African and African Caribbean people's contact with mental health services may stem from the organization, processes and practices of services themselves. This article presents the findings of a qualitative study which explored the inpatient experiences of a sample of African and African Caribbean people. Although some positive experiences were described, in the main, participants' accounts revolved around a sense of loss of control and around experiences of overt and implicit racism. Underpinning these experiences were relationships with staff that were perceived to be unhelpful. On the basis of both the positive and negative experiences described, we draw conclusions about the changes required to ensure that inpatient services more effectively meet the needs of this group.

  11. The Offshore East African Rift System

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  12. Approximate strip exchanging.

    PubMed

    Roy, Swapnoneel; Thakur, Ashok Kumar

    2008-01-01

    Genome rearrangements have been modelled by a variety of primitives such as reversals, transpositions, block moves and block interchanges. We consider such a genome rearrangement primitive Strip Exchanges. Given a permutation, the challenge is to sort it by using minimum number of strip exchanges. A strip exchanging move interchanges the positions of two chosen strips so that they merge with other strips. The strip exchange problem is to sort a permutation using minimum number of strip exchanges. We present here the first non-trivial 2-approximation algorithm to this problem. We also observe that sorting by strip-exchanges is fixed-parameter-tractable. Lastly we discuss the application of strip exchanges in a different area Optical Character Recognition (OCR) with an example.

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

    PubMed Central

    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 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. PMID:20161575

  14. 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…

  15. "African Connection."

    ERIC Educational Resources Information Center

    Adelman, Cathy; And Others

    This interdisciplinary unit provides students in grades kindergarten through seventh grade an opportunity to understand diversity through a study of Africa as a diverse continent. The project is designed to provide all elementary students with cultural enrichment by exposing them to African music, art, storytelling, and movement. This project can…

  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. 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.

  18. 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).

  19. 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…

  20. 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…

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

    ERIC Educational Resources Information Center

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

    2002-01-01

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

  2. Obesity and African Americans

    MedlinePlus

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

  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

    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.

  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 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

  5. Sparse pseudospectral approximation method

    NASA Astrophysics Data System (ADS)

    Constantine, Paul G.; Eldred, Michael S.; Phipps, Eric T.

    2012-07-01

    Multivariate global polynomial approximations - such as polynomial chaos or stochastic collocation methods - are now in widespread use for sensitivity analysis and uncertainty quantification. The pseudospectral variety of these methods uses a numerical integration rule to approximate the Fourier-type coefficients of a truncated expansion in orthogonal polynomials. For problems in more than two or three dimensions, a sparse grid numerical integration rule offers accuracy with a smaller node set compared to tensor product approximation. However, when using a sparse rule to approximately integrate these coefficients, one often finds unacceptable errors in the coefficients associated with higher degree polynomials. By reexamining Smolyak's algorithm and exploiting the connections between interpolation and projection in tensor product spaces, we construct a sparse pseudospectral approximation method that accurately reproduces the coefficients of basis functions that naturally correspond to the sparse grid integration rule. The compelling numerical results show that this is the proper way to use sparse grid integration rules for pseudospectral approximation.

  6. Approximations for photoelectron scattering

    NASA Astrophysics Data System (ADS)

    Fritzsche, V.

    1989-04-01

    The errors of several approximations in the theoretical approach of photoelectron scattering are systematically studied, in tungsten, for electron energies ranging from 10 to 1000 eV. The large inaccuracies of the plane-wave approximation (PWA) are substantially reduced by means of effective scattering amplitudes in the modified small-scattering-centre approximation (MSSCA). The reduced angular momentum expansion (RAME) is so accurate that it allows reliable calculations of multiple-scattering contributions for all the energies considered.

  7. 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.

  8. 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

  9. 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…

  10. Therapy with African Families.

    ERIC Educational Resources Information Center

    Nwadiora, Emeka

    1996-01-01

    Informs helping professionals about the unique history and challenges of African families to guide them toward providing ethnically sensitive psychological services to African immigrant families in need. African families undergo great stress when faced with the alienation of being Black and African in a Euro-American culture. (SLD)

  11. 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…

  12. 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.

  13. Approximate kernel competitive learning.

    PubMed

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

    2015-03-01

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

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

    PubMed

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

    2016-01-01

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

  15. 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.

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

    PubMed

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

    1991-01-01

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

  17. 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.

  18. Judgement Accuracy in Body Preferences among African Americans.

    ERIC Educational Resources Information Center

    Patel, Kushal A.; Gray, James J.

    2001-01-01

    Examined whether African Americans accurately estimated levels of thinness preferred by the opposite gender. College students rated pictures of figures approximating their current figure, their ideal figure, the figure most likely to attract the opposite gender, and the opposite gender figure they found most attractive. African American women…

  19. 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…

  20. Optimal approximate doubles

    NASA Astrophysics Data System (ADS)

    Huang, Siendong

    2009-11-01

    The nonlocality of quantum states on a bipartite system \\mathcal {A+B} is tested by comparing probabilistic outcomes of two local observables of different subsystems. For a fixed observable A of the subsystem \\mathcal {A,} its optimal approximate double A' of the other system \\mathcal {B} is defined such that the probabilistic outcomes of A' are almost similar to those of the fixed observable A. The case of σ-finite standard von Neumann algebras is considered and the optimal approximate double A' of an observable A is explicitly determined. The connection between optimal approximate doubles and quantum correlations is explained. Inspired by quantum states with perfect correlation, like Einstein-Podolsky-Rosen states and Bohm states, the nonlocality power of an observable A for general quantum states is defined as the similarity that the outcomes of A look like the properties of the subsystem \\mathcal {B} corresponding to A'. As an application of optimal approximate doubles, maximal Bell correlation of a pure entangled state on \\mathcal {B}(\\mathbb {C}^{2})\\otimes \\mathcal {B}(\\mathbb {C}^{2}) is found explicitly.

  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 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…

  3. Nutritional support of malnourished lactose intolerant African patients.

    PubMed Central

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

    1984-01-01

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

  4. The structural physical approximation conjecture

    NASA Astrophysics Data System (ADS)

    Shultz, Fred

    2016-01-01

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

  5. 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.

  6. Constraining the African pole of rotation

    NASA Astrophysics Data System (ADS)

    Asfaw, Laike M.

    1992-08-01

    In the absence of well defined transform faults in the East African rift system for constraining the plate kinematic reconstruction, the pole of relative motion for the African (Nubian) and Somalian plates has been determined from residual motion. If Africa and Somalia are to continue to drift apart along the East African rift system (which would then evolve into a series of ridges offset by transform faults) then incipient transform faults that may reflect the direction of relative motion should already be in place along the East African rift system. The incipient transforms along the East African rift system are characterized by shear zones, such as the Zambezi shear zone in the south and the Aswa and Hamer shear zones in the north. Some of these shear zones have been associated with recent strike-slip faulting in the NW-SE direction during periods of earthquakes. Provided that these, consistently NW-SE oriented, strike-slip movements in the shear zones give the direction of relative motion of the adjacent plates, then they can be used to constrain the position of the Africa-Somalia Euler pole. Due to the fact that identifying transform faults in the East African rift system is difficult and because the genesis of transform faults characterizing a plate boundary at an inception stage is not well known, the discussion here is limited to the northern segment of the East African rift system where shear zones are better characterized by the existing geophysical data. The characterizing features vary with latitude, indicating the complexity of the problem of the genesis of transform faults. I believe, however, that the relatively well defined intra-continental transform fault in the northern East African rift system, which is characterized by strike-slip faulting and earthquakes, constrains the pole of relative motion for the African and Somalian plates to a position near 1.5°S and 29.0°E.

  7. 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.

  8. 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…

  9. Linguistic Imperialism: African Perspectives.

    ERIC Educational Resources Information Center

    Phillipson, Robert

    1996-01-01

    Responds to an article on aspects of African language policy and discusses the following issues: multilingualism and monolingualism, proposed changes in language policy from the Organization for African Unity and South African initiatives, the language of literature, bilingual education, and whose interests English-language teaching is serving.…

  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. 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. PMID:26361047

  13. Perspectives from the historic African American medical institutions.

    PubMed

    Epps, C H

    1999-05-01

    The historically African American medical schools have been at the center of medical education for African American physicians in the United States since the Howard University College of Medicine opened in 1868. Although there were more than a dozen African American medical schools established during the next few decades, as propriety or church affiliated schools, only two survived the Flexner Report in 1910. Howard University (1868) and Meharry (1876) survived and trained generations of African Americans. These two schools educated approximately 85% of all African American physicians whereas the majority medical schools educated 15% for more than half of the twentieth century. As the result of a series of lawsuits filed by the National Association for the Advancement of Colored People, civil rights legislation and affirmative action programs, the numbers of the schools that now admitted African Americans increased and the total numbers of African American medical students increased when discrimination was prohibited in 1966. The percentage of African American medical students attending predominantly white institutions increased by 25% in 1948, by 47% in 1968, by 61% in 1983 and to 84% in 1990. Two additional predominantly African American medical schools were established: the Charles R. Drew Medical School, Los Angeles (affiliated with the University of California, Los Angeles) in 1966, and Morehouse Medical School, Atlanta, which admitted its first class in 1978. Recent court decisions prohibiting schools from considering race as factor in admission and the end of affirmative action programs have resulted in a drop in total minority enrollment. The historically African American medical schools, that admitted approximately 15% of the African American medical students during the era of affirmative action programs, will see this percentage decrease as the majority institutions admit fewer African American medical students and minority students. In the United States

  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. Approximate Bayesian multibody tracking.

    PubMed

    Lanz, Oswald

    2006-09-01

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

  16. Three Approximate Entropies

    NASA Astrophysics Data System (ADS)

    Lubkin, Elihu

    2002-04-01

    In 1993,(E. & T. Lubkin, Int.J.Theor.Phys. 32), 993 (1993) we gave exact mean trace of squared density matrix P for 3 models of an n-dimensional part of an nK-dimensional pure state. Models named: random nK ket (Haar); pure-pure driven by random Hamiltonian (Gauss); Gauss with n,K coupling reset small (weak). Neglecting higher powers of P gives the approximation: ln(n)- defines deficit = (n - 1)/2 which yields deficits, Haar: n((n+K)/(nK+1) - 1)/2 = ( n - 1/n - 1/K + 1/nnK )/2K + Order(f[n] / KKK); Gauss: (n/2)( (n+K)/(nK+1) + 2(nK+1-n-K)/nK(nK+1)(nK+3)) - 1/2 = ( n - 1/n - 1/K + 2/nK - 1/nnK )/2K + Order( f[n]/KKK ); weak: (n/2)(2(K+n)/((K+1)(n+1))) - 1/2 = (n/(n+1))(1 + (n-1)/K - (n-1)/KK + Order(f[n]/KKK)) - 1/2 [unreliable]. These would stay poor even as Karrow∞ unless deficit << 1 bit. Haar and Gauss come out good, but weak has too large a deficit. Though many authors (beginning with Don Page(D.N.Page, PRL 71), 1291 (1993)) have found the exact for Haar, I haven't yet seen exact for Gauss or for weak.

  17. Approximation by hinge functions

    SciTech Connect

    Faber, V.

    1997-05-01

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

  18. An approximate model for pulsar navigation simulation

    NASA Astrophysics Data System (ADS)

    Jovanovic, Ilija; Enright, John

    2016-02-01

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

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

    ERIC Educational Resources Information Center

    Jones, Vita L.

    2011-01-01

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

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

    ERIC Educational Resources Information Center

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

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

  1. 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…

  2. Perspectives of African-American women on infant mortality.

    PubMed

    Barnes, Glenna L

    2008-01-01

    Twice as many African-American infants die each year when compared to White infants. This study explores the lived experiences of African-American women to identify factors related to this racial gap in infant mortality. Thirteen African-American women from two Virginia towns participated in either a focus group or in-depth interviews. Content and interpretive analysis revealed several themes. Participants indicated that the experiences of stress and racism are constant factors in African-American women's lives and are inseparable from their pregnancy experiences. Participants noted the importance of social support and the health care provider-client relationship for positive pregnancy outcomes.

  3. 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…

  4. 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.

  5. Antimicrobial activity of selected South African medicinal plants

    PubMed Central

    2012-01-01

    Background Nearly 3,000 plant species are used as medicines in South Africa, with approximately 350 species forming the most commonly traded and used medicinal plants. In the present study, twelve South African medicinal plants were selected and tested for their antimicrobial activities against eight microbial species belonging to fungi, Mycobacteria, Gram-positive and Gram-negative bacteria. Methods The radiometric respiratory technique using the BACTEC 460 system was used for susceptibility testing against Mycobacterium tuberculosis, and the liquid micro-broth dilution was used for other antimicrobial assays. Results The results of the minimal inhibitory concentration (MIC) determinations indicated that the methanol extracts from Acacia karoo, Erythrophleum lasianthum and Salvia africana were able to prevent the growth of all the tested microorganisms. All other samples showed selective activities. MIC values below 100 μg/ml were recorded with A. karoo, C. dentate, E. lasianthum, P. obligun and S. africana on at least one of the nine tested microorganisms. The best activity (MIC value of 39.06 μg/ml) was noted with S. africana against E. coli, S. aureus and M. audouinii, and Knowltonia vesitoria against M. tuberculosis. Conclusion The overall results of the present work provide baseline information for the possible use of the studied South African plant extracts in the treatment of microbial infections. PMID:22704594

  6. A molecular phylogenetic study of southern African Apiaceae.

    PubMed

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

    2006-12-01

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

  7. 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…

  8. African Studies Computer Resources.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

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

  9. 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…

  10. 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…

  11. 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…

  12. 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…

  13. "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

  14. African horse sickness and African carnivores.

    PubMed

    Alexander, K A; Kat, P W; House, J; House, C; O'Brien, S J; Laurenson, M K; McNutt, J W; Osburn, B I

    1995-11-01

    African horse sickness (AHS) is a disease that affects equids, and is principally transmitted by Culicoides spp. that are biological vectors of AHS viruses (AHSV). The repeated spread of AHSV from sub-Saharan Africa to the Middle East, northern Africa and the Iberian peninsula indicate that a better understanding of AHS epizootiology is needed. African horse sickness has long been known to infect and cause mortality among domestic dogs that ingest virus contaminated meat, but it is uncertain what role carnivores play in transmission of the virus. We present evidence of widespread natural AHS infection among a diversity of African carnivore species. We hypothesize that such infection resulted from ingestion of meat and organs from AHS-infected prey species. The effect of AHS on the carnivores is unknown, as is their role in the maintenance cycle of the disease.

  15. Diabetes in African Americans

    PubMed Central

    Marshall, M

    2005-01-01

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

  16. Educational Resilience in African American Adolescents

    ERIC Educational Resources Information Center

    Cunningham, Michael; Swanson, Dena Phillips

    2010-01-01

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

  17. African bees to control African elephants

    NASA Astrophysics Data System (ADS)

    Vollrath, Fritz; Douglas-Hamilton, Iain

    2002-11-01

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

  18. 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…

  19. The presence of an RHD pseudogene containing a 37 base pair duplication and a nonsense mutation in africans with the Rh D-negative blood group phenotype.

    PubMed

    Singleton, B K; Green, C A; Avent, N D; Martin, P G; Smart, E; Daka, A; Narter-Olaga, E G; Hawthorne, L M; Daniels, G

    2000-01-01

    Antigens of the Rh blood group system are encoded by 2 homologous genes, RHD and RHCE, that produce 2 red cell membrane proteins. The D-negative phenotype is considered to result, almost invariably, from homozygosity for a complete deletion of RHD. The basis of all PCR tests for predicting fetal D phenotype from DNA obtained from amniocytes or maternal plasma is detection of the presence of RHD. These tests are used in order to ascertain the risk of hemolytic disease of the newborn. We have identified an RHD pseudogene (RHD psi) in Rh D-negative Africans. RHDpsi contains a 37 base pair (bp) insert in exon 4, which may introduce a stop codon at position 210. The insert is a sequence duplication across the boundary of intron 3 and exon 4. RHDpsi contains another stop codon in exon 6. The frequency of RHDpsi in black South Africans is approximately 0.0714. Of 82 D-negative black Africans, 66% had RHDpsi, 15% had the RHD-CE-D hybrid gene associated with the VS+ V- phenotype, and only 18% completely lacked RHD. RHDpsi is present in about 24% of D-negative African Americans and 17% of D-negative South Africans of mixed race. No RHD transcript could be detected in D-negative individuals with RHDpsi, probably as a result of nonsense-mediated mRNA decay. Existing PCR-based methods for predicting D phenotype from DNA are not suitable for testing Africans or any population containing a substantial proportion of people with African ethnicity. Consequently, we have developed a new test that detects the 37 bp insert in exon 4 of RHDpsi. (Blood. 2000; 95:12-18)

  20. 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.

  1. Rabies and African wild dogs in Kenya.

    PubMed

    Kat, P W; Alexander, K A; Smith, J S; Munson, L

    1995-11-22

    Three packs of African wild dogs (Lycaon pictus) ranging to the north of the Masai Mara National Reserve in southwestern Kenya were monitored from 1988 to 1990. During a six week period (August 2-September 14, 1989), 21 of 23 members of one of these packs died. Histological examination of two brain samples revealed eosinophilic intracytoplasmic inclusions (Negri bodies), supporting a diagnosis of rabies viral encephalitis. An additional brain sample tested positive for rabies with a fluorescent antibody test. Nucleotide sequence of the rabies viral N and G genes from isolates of four African wild dogs (including an individual from Tanzania) indicated that infection was with a viral variant common among domestic dogs in Kenya and Tanzania. A hypothesis linking African wild dog rabies deaths to researcher handling is evaluated and considered implausible.

  2. Frequency of False Positive Rapid HIV Serologic Tests in African Men and Women Receiving PrEP for HIV Prevention: Implications for Programmatic Roll-Out of Biomedical Interventions

    PubMed Central

    Ndase, Patrick; Celum, Connie; Kidoguchi, Lara; Ronald, Allan; Fife, Kenneth H.; Bukusi, Elizabeth; Donnell, Deborah; Baeten, Jared M.

    2015-01-01

    Background Rapid HIV assays are the mainstay of HIV testing globally. Delivery of effective biomedical HIV prevention strategies such as antiretroviral pre-exposure prophylaxis (PrEP) requires periodic HIV testing. Because rapid tests have high (>95%) but imperfect specificity, they are expected to generate some false positive results. Methods We assessed the frequency of true and false positive rapid results in the Partners PrEP Study, a randomized, placebo-controlled trial of PrEP. HIV testing was performed monthly using 2 rapid tests done in parallel with HIV enzyme immunoassay (EIA) confirmation following all positive rapid tests. Results A total of 99,009 monthly HIV tests were performed; 98,743 (99.7%) were dual-rapid HIV negative. Of the 266 visits with ≥1 positive rapid result, 99 (37.2%) had confirmatory positive EIA results (true positives), 155 (58.3%) had negative EIA results (false positives), and 12 (4.5%) had discordant EIA results. In the active PrEP arms, over two-thirds of visits with positive rapid test results were false positive results (69.2%, 110 of 159), although false positive results occurred at <1% (110/65,945) of total visits. Conclusions When HIV prevalence or incidence is low due to effective HIV prevention interventions, rapid HIV tests result in a high number of false relative to true positive results, although the absolute number of false results will be low. Program roll-out for effective interventions should plan for quality assurance of HIV testing, mechanisms for confirmatory HIV testing, and counseling strategies for persons with positive rapid test results. PMID:25885664

  3. 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. PMID:24352586

  4. Astronomy for African development

    NASA Astrophysics Data System (ADS)

    Govender, Kevindran

    2011-06-01

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

  5. African American Health

    MedlinePlus

    ... specific health concerns. Differences in the health of groups can result from Genetics Environmental factors Access to care Cultural factors On this page, you'll find links to health issues that affect African Americans.

  6. 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. ...

  7. 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.

  8. 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"…

  9. 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.

  10. Approximate circuits for increased reliability

    DOEpatents

    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.

  11. Fostering Formal Commutativity Knowledge with Approximate Arithmetic.

    PubMed

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

    2015-01-01

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

  12. 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

  13. 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…

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  15. African American College Students at a Predominantly White Institution: Patterns of Success.

    ERIC Educational Resources Information Center

    Hall, Clover

    This study investigated factors affecting the success of African American students at a large, predominantly white, Catholic commuter institution, with approximately 10 percent African American enrollment. The study examined how students perceived campus climate; environmental factors impeding success and contributing to success; the effect of…

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

    ERIC Educational Resources Information Center

    Steppes, Allison Victoria

    2011-01-01

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

  17. Biological evaluation of Trans-African highways

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  18. "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…

  19. Sun protection behaviors among African Americans.

    PubMed

    Hall, H I; Rogers, J D

    1999-01-01

    The anatomic distribution of some skin cancers suggests that sun exposure may be an etiologic factor for skin cancer among African Americans. Yet little is known about sun protection behaviors among African Americans. We analyzed data from the 1992 National Health Interview Survey (N = 1,583) to determine the prevalence of sun protection behaviors and sun sensitivity. About 6% of African Americans reported being extremely sensitive to the sun and severe sunburning, and 9% reported mild burns. Overall, 53% of respondents (47% of men and 57% of women) reported that they were very likely to wear protective clothing, seek shade, or use sunscreen lotion. Women were more likely than men to report seeking shade and using sunscreen. Sun protection behaviors were more frequently reported by those who sunburn more easily and were positively associated with age. Use of sunscreen was positively associated with income and education. Education about sun protection and early detection may help reduce the morbidity and mortality of skin cancer among African Americans.

  20. 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

  1. 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.

  2. Support Needs of Overweight African American Women for Weight Loss

    PubMed Central

    Thomas, Janet L.; Stewart, Diana W.; Lynam, Ian M.; Daley, Christine M.; Befort, Christie; Scherber, Robyn M.; Mercurio, Andrea E.; Okuyemi, Kolawole S.; Ahluwalia, Jasjit S.

    2014-01-01

    Objectives To examine social support needs of obese and over-weight African American women for weight loss. Methods Focus groups were conducted with over-weight and obese African American women. Data were analyzed using standard grounded theory text analysis. Results Our middle-aged (45.7 years; SD=12.6) women (N = 66) were interested in receiving support from others focused on the health benefits of weight loss. Behaviors perceived as supportive include co-participating in exercise, providing nutrition education, using positive reinforcements, and avoiding criticism. Conclusions: African American women are interested in a program designed to increase social support for their weight loss. PMID:19182980

  3. African-Americans and Alzheimer's

    MedlinePlus

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

  4. Transcriptome population genomics reveals severe bottleneck and domestication cost in the African rice (Oryza glaberrima).

    PubMed

    Nabholz, Benoit; Sarah, Gautier; Sabot, François; Ruiz, Manuel; Adam, Hélène; Nidelet, Sabine; Ghesquière, Alain; Santoni, Sylvain; David, Jacques; Glémin, Sylvain

    2014-05-01

    The African cultivated rice (Oryza glaberrima) was domesticated in West Africa 3000 years ago. Although less cultivated than the Asian rice (O. sativa), O. glaberrima landraces often display interesting adaptation to rustic environment (e.g. drought). Here, using RNA-seq technology, we were able to compare more than 12,000 transcripts between 9 O. glaberrima, 10 wild O. barthii and one O. meridionalis individuals. With a synonymous nucleotide diversity πs = 0.0006 per site, O. glaberrima appears as the least genetically diverse crop grass ever documented. Using approximate Bayesian computation, we estimated that O. glaberrima experienced a severe bottleneck during domestication. This demographic scenario almost fully accounts for the pattern of genetic diversity across O. glaberrima genome as we detected very few outliers regions where positive selection may have further impacted genetic diversity. Moreover, the large excess of derived nonsynonymous substitution that we detected suggests that the O. glaberrima population suffered from the 'cost of domestication'. In addition, we used this genome-scale data set to demonstrate that (i) O. barthii genetic diversity is positively correlated with recombination rate and negatively with gene density, (ii) expression level is negatively correlated with evolutionary constraint, and (iii) one region on chromosome 5 (position 4-6 Mb) exhibits a clear signature of introgression with a yet unidentified Oryza species. This work represents the first genome-wide survey of the African rice genetic diversity and paves the way for further comparison between the African and the Asian rice, notably regarding the genetics underlying domestication traits.

  5. 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

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

    PubMed

    Green-McKenzie, Judith

    2004-03-01

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

  7. Wavelet Sparse Approximate Inverse Preconditioners

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  8. 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

  9. 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.

  10. English as an African Language.

    ERIC Educational Resources Information Center

    Desai, Gaurav

    1993-01-01

    Discusses the role of the English language in postcolonial African literature, focusing on the politics of language, "Africanized" English, and the social languages used in Chinua Achebe's novels and concludes that English today is as much an African language as a British or American one. (Contains 37 references.) (MDM)

  11. 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…

  12. 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.

  13. 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…

  14. The making of the African mtDNA landscape.

    PubMed

    Salas, Antonio; Richards, Martin; De la Fe, Tomás; Lareu, María-Victoria; Sobrino, Beatriz; Sánchez-Diz, Paula; Macaulay, Vincent; Carracedo, Angel

    2002-11-01

    Africa presents the most complex genetic picture of any continent, with a time depth for mitochondrial DNA (mtDNA) lineages >100,000 years. The most recent widespread demographic shift within the continent was most probably the Bantu dispersals, which archaeological and linguistic evidence suggest originated in West Africa 3,000-4,000 years ago, spreading both east and south. Here, we have carried out a thorough phylogeographic analysis of mtDNA variation in a total of 2,847 samples from throughout the continent, including 307 new sequences from southeast African Bantu speakers. The results suggest that the southeast Bantu speakers have a composite origin on the maternal line of descent, with approximately 44% of lineages deriving from West Africa, approximately 21% from either West or Central Africa, approximately 30% from East Africa, and approximately 5% from southern African Khoisan-speaking groups. The ages of the major founder types of both West and East African origin are consistent with the likely timing of Bantu dispersals, with those from the west somewhat predating those from the east. Despite this composite picture, the southeastern African Bantu groups are indistinguishable from each other with respect to their mtDNA, suggesting that they either had a common origin at the point of entry into southeastern Africa or have undergone very extensive gene flow since.

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

    ERIC Educational Resources Information Center

    Braden, Warren R.

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

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

    PubMed Central

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

    2010-01-01

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

  17. Self-care and mothering in African American women with HIV/AIDS.

    PubMed

    Shambley-Ebron, Donna Z; Boyle, Joyceen S

    2006-02-01

    African American women are the most rapidly growing group of people in the United States diagnosed with HIV/AIDS. The purpose of this study was to explore experiences of self-care and mothering among African American women with HIV/AIDS. It is important to recognize how culture affects illness management, childrearing, and daily living to design culturally appropriate nursing interventions for African American women. Critical ethnography was used to study 10 African American mothers from the rural Southeast who were HIV positive and mothered children who were HIV positive. Domains derived from the research were disabling relationships, strong mothering, and redefining self-care. The cultural theme was creating a life of meaning. African American mothers with HIV/AIDS in the rural Southeast used culturally specific self-care and mothering strategies reflective of cultural traditions. This study acknowledges strengths of African American women and generates theory that will enhance nursing care to this population. PMID:16676725

  18. 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…

  19. Error Bounds for Interpolative Approximations.

    ERIC Educational Resources Information Center

    Gal-Ezer, J.; Zwas, G.

    1990-01-01

    Elementary error estimation in the approximation of functions by polynomials as a computational assignment, error-bounding functions and error bounds, and the choice of interpolation points are discussed. Precalculus and computer instruction are used on some of the calculations. (KR)

  20. 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

  1. 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.

  2. RHD allele distribution in Africans of Mali

    PubMed Central

    Wagner, Franz F; Moulds, Joann M; Tounkara, Anatole; Kouriba, Bourema; Flegel, Willy A

    2003-01-01

    Background Aberrant and non-functional RHD alleles are much more frequent in Africans than in Europeans. The DAU cluster of RHD alleles exemplifies that the alleles frequent in Africans have evaded recognition until recently. A comprehensive survey of RHD alleles in any African population was lacking. Results We surveyed the molecular structure and frequency of RHD alleles in Mali (West Africa) by evaluating 116 haplotypes. Only 69% could be attributed to standard RHD (55%) or the RHD deletion (14%). The aberrant RHD allele DAU-0 was predicted for 19%, RHDΨ for 7% and Ccdes for 4% of all haplotypes. DAU-3 and the new RHD allele RHD(L207F), dubbed DMA, were found in one haplotype each. A PCR-RFLP for the detection of the hybrid Rhesus box diagnostic for the RHD deletion in Europeans was false positive in 9 individuals, including all carriers of RHDΨ . Including two silent mutations and the RHD deletion, a total of 9 alleles could be differentiated. Conclusion Besides standard RHD and the RHD deletion, DAU-0, RHDΨ and Ccdes are major alleles in Mali. Our survey proved that the most frequent alleles of West Africans have been recognized allowing to devise reliable genotyping and phenotyping strategies. PMID:14505497

  3. Chemical Laws, Idealization and Approximation

    NASA Astrophysics Data System (ADS)

    Tobin, Emma

    2013-07-01

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

  4. 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

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

    PubMed

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

    2007-04-01

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

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

    PubMed Central

    Barnett, Melissa A.; Scaramella, Laura V.

    2014-01-01

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

  7. 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.

  8. The Other African Americans.

    ERIC Educational Resources Information Center

    Matory, J. Lorand

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

  9. African Oral Tradition Literacy.

    ERIC Educational Resources Information Center

    Green, Doris

    1985-01-01

    Presents the basic principles of two systems for notating African music and dance: Labanotation (created to record and analyze movements) and Greenotation (created to notate musical instruments of Africa and to parallel Labanotation whereby both music and dance are incorporated into one integrated score). (KH)

  10. 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…

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

    PubMed

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

    2003-06-01

    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.

  12. 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

  13. 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…

  14. 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.

  15. Approximate line shapes for hydrogen

    NASA Technical Reports Server (NTRS)

    Sutton, K.

    1978-01-01

    Two independent methods are presented for calculating radiative transport within hydrogen lines. In Method 1, a simple equation is proposed for calculating the line shape. In Method 2, the line shape is assumed to be a dispersion profile and an equation is presented for calculating the half half-width. The results obtained for the line shapes and curves of growth by the two approximate methods are compared with similar results using the detailed line shapes by Vidal et al.

  16. 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.

  17. 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.

  18. Ultrafast approximation for phylogenetic bootstrap.

    PubMed

    Minh, Bui Quang; Nguyen, Minh Anh Thi; von Haeseler, Arndt

    2013-05-01

    Nonparametric bootstrap has been a widely used tool in phylogenetic analysis to assess the clade support of phylogenetic trees. However, with the rapidly growing amount of data, this task remains a computational bottleneck. Recently, approximation methods such as the RAxML rapid bootstrap (RBS) and the Shimodaira-Hasegawa-like approximate likelihood ratio test have been introduced to speed up the bootstrap. Here, we suggest an ultrafast bootstrap approximation approach (UFBoot) to compute the support of phylogenetic groups in maximum likelihood (ML) based trees. To achieve this, we combine the resampling estimated log-likelihood method with a simple but effective collection scheme of candidate trees. We also propose a stopping rule that assesses the convergence of branch support values to automatically determine when to stop collecting candidate trees. UFBoot achieves a median speed up of 3.1 (range: 0.66-33.3) to 10.2 (range: 1.32-41.4) compared with RAxML RBS for real DNA and amino acid alignments, respectively. Moreover, our extensive simulations show that UFBoot is robust against moderate model violations and the support values obtained appear to be relatively unbiased compared with the conservative standard bootstrap. This provides a more direct interpretation of the bootstrap support. We offer an efficient and easy-to-use software (available at http://www.cibiv.at/software/iqtree) to perform the UFBoot analysis with ML tree inference.

  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. 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

  1. Transgenerational Consequences of Racial Discrimination for African American Health.

    PubMed

    Goosby, Bridget J; Heidbrink, Chelsea

    2013-08-01

    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.

  2. Adapting an evidence-based HIV prevention intervention for pregnant African-American women in substance abuse treatment

    PubMed Central

    Wechsberg, Wendee M; Browne, Felicia A; Poulton, Winona; Ellerson, Rachel Middlesteadt; Simons-Rudolph, Ashley; Haller, Deborah

    2011-01-01

    An adaptation of an evidence-based, woman-focused intervention designed to reduce HIV risk behaviors was conducted for pregnant, African-American women in substance abuse treatment in North Carolina. The intervention adaptation process included focus groups, expert panels, and the filming of women who spoke about their experiences with pregnancy, drug use, sex risk behaviors, HIV testing and treatment, need for substance abuse treatment, violence, and victimization. The assessment instrument was adapted for pregnant women and the intervention was organized into a 4-session PowerPoint presentation, with an additional session if a woman tested positive for HIV. All sessions and assessment instrument were installed on laptop computers for portability in treatment programs. We pilot tested our adaptation with 59 pregnant African-American women who had used an illicit drug within the past year and were enrolled in substance abuse treatment. At baseline, 41% were currently homeless, 76% were unemployed, 90% had not planned their current pregnancy, and approximately 70% reported drug use since finding out about the pregnancy. This sample of participants rated the intervention sessions and were highly satisfied with their experience, resulting in a mean satisfaction score of 6.5 out of 7. Pregnant African-American women who use drugs need substance abuse treatment that they do not currently access. Woman-focused HIV interventions help to address intersecting risk behaviors and need for treatment prevalent among this vulnerable group. PMID:24474853

  3. 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

  4. Approximately Independent Features of Languages

    NASA Astrophysics Data System (ADS)

    Holman, Eric W.

    To facilitate the testing of models for the evolution of languages, the present paper offers a set of linguistic features that are approximately independent of each other. To find these features, the adjusted Rand index (R‧) is used to estimate the degree of pairwise relationship among 130 linguistic features in a large published database. Many of the R‧ values prove to be near zero, as predicted for independent features, and a subset of 47 features is found with an average R‧ of -0.0001. These 47 features are recommended for use in statistical tests that require independent units of analysis.

  5. 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.}

  6. Quantum tunneling beyond semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Banerjee, Rabin; Ranjan Majhi, Bibhas

    2008-06-01

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

  7. Fermion tunneling beyond semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Majhi, Bibhas Ranjan

    2009-02-01

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

  8. 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

  9. Approximate neutral point of a subsonic canard aircraft

    NASA Technical Reports Server (NTRS)

    Phillips, J. D.

    1985-01-01

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

  10. 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…

  11. 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…

  12. 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…

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

    ERIC Educational Resources Information Center

    Harris, LeCharle Webb

    2009-01-01

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

  14. 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…

  15. 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…

  16. 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…

  17. 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.

  18. Understanding traditional African healing

    PubMed Central

    MOKGOBI, M.G.

    2015-01-01

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

  19. Plasma Physics Approximations in Ares

    SciTech Connect

    Managan, R. A.

    2015-01-08

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

  20. 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.

  1. 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.

  2. 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

  3. African horse sickness.

    PubMed

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

    2015-08-01

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

  4. East African Rift Valley, Kenya

    NASA Technical Reports Server (NTRS)

    1990-01-01

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

  5. 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

  6. Associations between Central Nervous System Serotonin, Fasting Glucose and Hostility in African American Females

    PubMed Central

    Boyle, Stephen H.; Georgiades, Anastasia; Brummett, Beverly H.; Barefoot, John C.; Siegler, Ilene C.; Matson, Wayne R.; Kuhn, Cynthia M.; Grichnik, Katherine; Stafford-Smith, Mark; Williams, Redford B.; Kaddurah-Daouk, Rima; Surwit, Richard S.

    2015-01-01

    Background Previous research has shown an association between hostility and fasting glucose in African American women. Central nervous system serotonin activity is implicated both in metabolic processes and in hostility related traits. Purpose To determine whether central nervous system serotonin influences the association between hostility and fasting glucose in African American women. Methods The study consisted of 119 healthy volunteers (36 African American women, 27 white women, 21 white males, and 35 African American males, mean age 34±8.5 years). Serotonin metabolites were measured in cerebrospinal fluid. Hostility was measured by the Cook-Medley Hostility Scale. Results Hostility was associated with fasting glucose and central nervous system serotonin metabolites in African American women only. Controlling for the serotonin metabolites significantly reduced the association of hostility to glucose. Conclusions The positive correlation between hostility and fasting glucose in African American women can partly be explained by central nervous system serotonin function. PMID:24806470

  7. An African ancestry-specific allele of CTLA4 confers protection against rheumatoid arthritis in African Americans.

    PubMed

    Kelley, James M; Hughes, Laura B; Faggard, Jeffrey D; Danila, Maria I; Crawford, Monica H; Edberg, Yuanqing; Padilla, Miguel A; Tiwari, Hemant K; Westfall, Andrew O; Alarcón, Graciela S; Conn, Doyt L; Jonas, Beth L; Callahan, Leigh F; Smith, Edwin A; Brasington, Richard D; Allison, David B; Kimberly, Robert P; Moreland, Larry W; Edberg, Jeffrey C; Bridges, S Louis

    2009-03-01

    Cytotoxic T-lymphocyte associated protein 4 (CTLA4) is a negative regulator of T-cell proliferation. Polymorphisms in CTLA4 have been inconsistently associated with susceptibility to rheumatoid arthritis (RA) in populations of European ancestry but have not been examined in African Americans. The prevalence of RA in most populations of European and Asian ancestry is approximately 1.0%; RA is purportedly less common in black Africans, with little known about its prevalence in African Americans. We sought to determine if CTLA4 polymorphisms are associated with RA in African Americans. We performed a 2-stage analysis of 12 haplotype tagging single nucleotide polymorphisms (SNPs) across CTLA4 in a total of 505 African American RA patients and 712 African American controls using Illumina and TaqMan platforms. The minor allele (G) of the rs231778 SNP was 0.054 in RA patients, compared to 0.209 in controls (4.462 x 10(-26), Fisher's exact). The presence of the G allele was associated with a substantially reduced odds ratio (OR) of having RA (AG+GG genotypes vs. AA genotype, OR 0.19, 95% CI: 0.13-0.26, p = 2.4 x 10(-28), Fisher's exact), suggesting a protective effect. This SNP is polymorphic in the African population (minor allele frequency [MAF] 0.09 in the Yoruba population), but is very rare in other groups (MAF = 0.002 in 530 Caucasians genotyped for this study). Markers associated with RA in populations of European ancestry (rs3087243 [+60C/T] and rs231775 [+49A/G]) were not replicated in African Americans. We found no confounding of association for rs231778 after stratifying for the HLA-DRB1 shared epitope, presence of anti-cyclic citrullinated peptide antibody, or degree of admixture from the European population. An African ancestry-specific genetic variant of CTLA4 appears to be associated with protection from RA in African Americans. This finding may explain, in part, the relatively low prevalence of RA in black African populations.

  8. Approximating metal-insulator transitions

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  9. New generalized gradient approximation functionals

    NASA Astrophysics Data System (ADS)

    Boese, A. Daniel; Doltsinis, Nikos L.; Handy, Nicholas C.; Sprik, Michiel

    2000-01-01

    New generalized gradient approximation (GGA) functionals are reported, using the expansion form of A. D. Becke, J. Chem. Phys. 107, 8554 (1997), with 15 linear parameters. Our original such GGA functional, called HCTH, was determined through a least squares refinement to data of 93 systems. Here, the data are extended to 120 systems and 147 systems, introducing electron and proton affinities, and weakly bound dimers to give the new functionals HCTH/120 and HCTH/147. HCTH/120 has already been shown to give high quality predictions for weakly bound systems. The functionals are applied in a comparative study of the addition reaction of water to formaldehyde and sulfur trioxide, respectively. Furthermore, the performance of the HCTH/120 functional in Car-Parrinello molecular dynamics simulations of liquid water is encouraging.

  10. Interplay of approximate planning strategies.

    PubMed

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

    2015-03-10

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

  11. 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. PMID:24361686

  12. IONIS: Approximate atomic photoionization intensities

    NASA Astrophysics Data System (ADS)

    Heinäsmäki, Sami

    2012-02-01

    A program to compute relative atomic photoionization cross sections is presented. The code applies the output of the multiconfiguration Dirac-Fock method for atoms in the single active electron scheme, by computing the overlap of the bound electron states in the initial and final states. The contribution from the single-particle ionization matrix elements is assumed to be the same for each final state. This method gives rather accurate relative ionization probabilities provided the single-electron ionization matrix elements do not depend strongly on energy in the region considered. The method is especially suited for open shell atoms where electronic correlation in the ionic states is large. Program summaryProgram title: IONIS Catalogue identifier: AEKK_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKK_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1149 No. of bytes in distributed program, including test data, etc.: 12 877 Distribution format: tar.gz Programming language: Fortran 95 Computer: Workstations Operating system: GNU/Linux, Unix Classification: 2.2, 2.5 Nature of problem: Photoionization intensities for atoms. Solution method: The code applies the output of the multiconfiguration Dirac-Fock codes Grasp92 [1] or Grasp2K [2], to compute approximate photoionization intensities. The intensity is computed within the one-electron transition approximation and by assuming that the sum of the single-particle ionization probabilities is the same for all final ionic states. Restrictions: The program gives nonzero intensities for those transitions where only one electron is removed from the initial configuration(s). Shake-type many-electron transitions are not computed. The ionized shell must be closed in the initial state. Running time: Few seconds for a

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

    PubMed

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

    2015-09-01

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

  14. 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

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

    ERIC Educational Resources Information Center

    O'Brien, Sara Talis

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

  16. A review of genetics, arterial stiffness, and blood pressure in African Americans.

    PubMed

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

    2012-06-01

    The prevalence of hypertension in African Americans in the USA is among 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.

  17. Limited Evidence for Classic Selective Sweeps in African Populations

    PubMed Central

    Granka, Julie M.; Henn, Brenna M.; Gignoux, Christopher R.; Kidd, Jeffrey M.; Bustamante, Carlos D.; Feldman, Marcus W.

    2012-01-01

    While hundreds of loci have been identified as reflecting strong-positive selection in human populations, connections between candidate loci and specific selective pressures often remain obscure. This study investigates broader patterns of selection in African populations, which are underrepresented despite their potential to offer key insights into human adaptation. We scan for hard selective sweeps using several haplotype and allele-frequency statistics with a data set of nearly 500,000 genome-wide single-nucleotide polymorphisms in 12 highly diverged African populations that span a range of environments and subsistence strategies. We find that positive selection does not appear to be a strong determinant of allele-frequency differentiation among these African populations. Haplotype statistics do identify putatively selected regions that are shared across African populations. However, as assessed by extensive simulations, patterns of haplotype sharing between African populations follow neutral expectations and suggest that tails of the empirical distributions contain false-positive signals. After highlighting several genomic regions where positive selection can be inferred with higher confidence, we use a novel method to identify biological functions enriched among populations’ empirical tail genomic windows, such as immune response in agricultural groups. In general, however, it seems that current methods for selection scans are poorly suited to populations that, like the African populations in this study, are affected by ascertainment bias and have low levels of linkage disequilibrium, possibly old selective sweeps, and potentially reduced phasing accuracy. Additionally, population history can confound the interpretation of selection statistics, suggesting that greater care is needed in attributing broad genetic patterns to human adaptation. PMID:22960214

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

    PubMed Central

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

    2015-01-01

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

  19. Urinary CYP eicosanoid excretion correlates with glomerular filtration in African-Americans with chronic kidney disease.

    PubMed

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

    2014-10-01

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

  20. Multidimensional stochastic approximation Monte Carlo.

    PubMed

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

    2016-06-01

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

  1. Interplay of approximate planning strategies

    PubMed Central

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

    2015-01-01

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

  2. 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) .

  3. Semiclassics beyond the diagonal approximation

    NASA Astrophysics Data System (ADS)

    Turek, Marko

    2004-05-01

    The statistical properties of the energy spectrum of classically chaotic closed quantum systems are the central subject of this thesis. It has been conjectured by O.Bohigas, M.-J.Giannoni and C.Schmit that the spectral statistics of chaotic systems is universal and can be described by random-matrix theory. This conjecture has been confirmed in many experiments and numerical studies but a formal proof is still lacking. In this thesis we present a semiclassical evaluation of the spectral form factor which goes beyond M.V.Berry's diagonal approximation. To this end we extend a method developed by M.Sieber and K.Richter for a specific system: the motion of a particle on a two-dimensional surface of constant negative curvature. In particular we prove that these semiclassical methods reproduce the random-matrix theory predictions for the next to leading order correction also for a much wider class of systems, namely non-uniformly hyperbolic systems with f>2 degrees of freedom. We achieve this result by extending the configuration-space approach of M.Sieber and K.Richter to a canonically invariant phase-space approach.

  4. Randomized approximate nearest neighbors algorithm.

    PubMed

    Jones, Peter Wilcox; Osipov, Andrei; Rokhlin, Vladimir

    2011-09-20

    We present a randomized algorithm for the approximate nearest neighbor problem in d-dimensional Euclidean space. Given N points {x(j)} in R(d), the algorithm attempts to find k nearest neighbors for each of x(j), where k is a user-specified integer parameter. The algorithm is iterative, and its running time requirements are proportional to T·N·(d·(log d) + k·(d + log k)·(log N)) + N·k(2)·(d + log k), with T the number of iterations performed. The memory requirements of the procedure are of the order N·(d + k). A by-product of the scheme is a data structure, permitting a rapid search for the k nearest neighbors among {x(j)} for an arbitrary point x ∈ R(d). The cost of each such query is proportional to T·(d·(log d) + log(N/k)·k·(d + log k)), and the memory requirements for the requisite data structure are of the order N·(d + k) + T·(d + N). The algorithm utilizes random rotations and a basic divide-and-conquer scheme, followed by a local graph search. We analyze the scheme's behavior for certain types of distributions of {x(j)} and illustrate its performance via several numerical examples.

  5. 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.

  6. '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.

  7. African-American Children's Literature.

    ERIC Educational Resources Information Center

    Kline, Lucinda

    This paper examines the history of African American children's literature, the present-day status of it, and ventures predictions about its future. The paper also considers the historic and social factors of the debate about whether an author who is not African American can write a book that will/should be accepted in this category of children's…

  8. African-American Sacred Music.

    ERIC Educational Resources Information Center

    Bailey, A. Peter

    1991-01-01

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

  9. 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

  10. 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

  11. The history of African trypanosomiasis

    PubMed Central

    Steverding, Dietmar

    2008-01-01

    The prehistory of African trypanosomiasis indicates that the disease may have been an important selective factor in the evolution of hominids. Ancient history and medieval history reveal that African trypanosomiasis affected the lives of people living in sub-Saharan African at all times. Modern history of African trypanosomiasis revolves around the identification of the causative agents and the mode of transmission of the infection, and the development of drugs for treatment and methods for control of the disease. From the recent history of sleeping sickness we can learn that the disease can be controlled but probably not be eradicated. Current history of human African trypanosomiasis has shown that the production of anti-sleeping sickness drugs is not always guaranteed, and therefore, new, better and cheaper drugs are urgently required. PMID:18275594

  12. Nursing Positions

    MedlinePlus

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

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

    PubMed

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

    1994-04-01

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

  14. 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)

  15. 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…

  16. "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)

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  18. 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…

  19. 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…

  20. Cardiovascular Health Promotion in North Florida African-American Churches.

    ERIC Educational Resources Information Center

    Turner, Lori W.; And Others

    1995-01-01

    This article describes cardiovascular problems of minority populations, exploring ways that churches can help their communities and describing the outcomes of a model intervention on four African American churches in rural north Florida. Positive outcomes were observed, particularly regarding community members' participation in health promotion…

  1. Successful African American Women School Leaders in Florida

    ERIC Educational Resources Information Center

    Waldron-Asuncion, Alma

    2016-01-01

    The focus of this basic qualitative study was to explore the lived experiences of Floridian African American women in secondary educational leadership positions. Using critical race theory and Black feminist standpoint theory as a theoretical framework, this narrative analysis serves to increase the understanding of leadership styles among a…

  2. Antibody response to canine distemper vaccine in African wild dogs.

    PubMed

    Spencer, J; Burroughs, R

    1992-07-01

    Antibody levels against canine distemper virus were measured by means of an immunofluorescent antibody test prior to, and after, administration of a modified-live virus booster vaccine to seven African wild dogs (Lycaon pictus). Positive seroconversion with no harmful side-effects was seen in all the animals.

  3. 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…

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

    PubMed

    1999-05-01

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

  5. Successes and Challenges in East African Conservation Education

    ERIC Educational Resources Information Center

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

    2005-01-01

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

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

    ERIC Educational Resources Information Center

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

    1999-01-01

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

  7. 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.

  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. Bioenergy and African transformation.

    PubMed

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

    2015-01-01

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

  10. 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.

  11. 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.

  12. Positional plagiocephaly

    PubMed Central

    Cummings, Carl

    2011-01-01

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

  13. Successfully Educating Our African-American Students

    ERIC Educational Resources Information Center

    Moncree-Moffett, Kareem

    2013-01-01

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

  14. African American Smokers’ Intention to Use Pharmacotherapy for Cessation

    PubMed Central

    Lynam, Ian; Catley, Delwyn; Harris, Kari Jo; Goggin, Kathy; Berkley-Patton, Jannette; Thomas, Janet

    2012-01-01

    Objectives To use the theory of planned behavior to identify predictors of intentions to use cessation aids when quitting smoking. Methods African American smokers completed a survey to assess intentions, attitudes, and normative and control beliefs regarding the use of smoking cessation aids. Results Participants held mildly positive attitudes regarding the use of cessation aids. Beliefs related to the utility of aids, support of referents, and accessibility of a doctor were most strongly associated with intention to use cessation aids. Conclusions African American smokers may be amenable to the use of cessation aids, and specific beliefs may be targets for intervention. PMID:22584089

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

    PubMed Central

    Agyemang, C.; Bhopal, R.; Bruijnzeels, M.

    2005-01-01

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

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

    PubMed

    Agyemang, Charles; Bhopal, Raj; Bruijnzeels, Marc

    2005-12-01

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

  17. The Columbian Quincentenary: NCSS Position Statement.

    ERIC Educational Resources Information Center

    Social Studies and the Young Learner, 1992

    1992-01-01

    Offers the National Council for the Social Studies' official position on Christopher Columbus' voyages to the Americas. Acknowledges the roles of Native Americans, Africans, and Asians in the Age of Discovery. Recognizes the effects of Columbus' contacts with the other cultures of the Americas. Explores the contemporary relevance of 1492. (SG)

  18. Satellite positioning

    NASA Technical Reports Server (NTRS)

    Colombo, Oscar L.; Watkins, Michael M.

    1991-01-01

    Developments in satellite positioning techniques and their applications are reviewed on the basis of the theoretical and practical work published by U.S. researchers in 1987-1990. Current techniques are classified into two main categories: satellite laser tracking and radio tracking. Particular attention is given to the Geoscience Laser Ranging System, the Lunar Laser Ranging concept; GPS ephemerides determination, fiducial networks, and reference frame; static GPS positioning; and kinematic GPS positioning.

  19. 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

  20. 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.

  1. Assessment of religious and spiritual capital in African American communities.

    PubMed

    Holt, Cheryl L; Schulz, Emily; Williams, Beverly; Clark, Eddie M; Wang, Min Qi; Southward, Penny L

    2012-12-01

    African American faith communities are an important source of social capital. The present study adapted a theory-based social capital instrument to result in religious (e.g., from organized worship) and spiritual (e.g., from relationship with higher power) capital measures. Data from a national sample of 803 African Americans suggest the instruments have high internal reliability and are distinct from general religiosity. Measurement models confirmed factor structures. Religious capital was positively associated with self-rated health status. Religious and spiritual capital were negatively associated with depressive symptoms, but these associations largely became nonsignificant in multivariate models that controlled for demographic characteristics. An exception is for spiritual capital in the form of community participation, which retained a negative association with depressive symptoms. These instruments may have applied value for health promotion research and practice in African American communities.

  2. Perceptions of Support Among Older African American Cancer Survivors

    PubMed Central

    Hamilton, Jill B.; Moore, Charles E.; Powe, Barbara D.; Agarwal, Mansi; Martin, Pamela

    2010-01-01

    Purpose/Objectives To explore the perceived social support needs among older adult African American cancer survivors. Research Approach Qualitative design using grounded theory techniques. Setting Outpatient oncology clinics in the southeastern United States. Participants Focus groups with 22 older adult African American cancer survivors. Methodologic Approach Purposeful sampling technique was used to identify focus group participants. In-depth interviews were conducted and participants were interviewed until informational redundancy was achieved. Main Research Variables Social support needs of older adult African American patients with cancer. Findings Social support was influenced by (a) symptoms and treatment side effects, (b) perceptions of stigma and fears expressed by family and friends, (c) cultural beliefs about cancer, and (d) desires to lessen any burden or disruption to the lives of family and friends. Survivors navigated within and outside of their networks to get their social support needs met. In some instances, survivors socially withdrew from traditional sources of support for fear of being ostracized. Survivors also described feeling hurt, alone, and socially isolated when completely abandoned by friends. Conclusions The support from family, friends, and fellow church members is important to positive outcomes among older African American cancer survivors. However, misconceptions, fears, and negative cultural beliefs persist within the African American community and negatively influence the social support available to this population. Interpretations Early identification of the factors that influence social support can facilitate strategies to improve outcomes and decrease health disparities among this population. PMID:20591808

  3. 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…

  4. "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

  5. Positioning Agility

    NASA Astrophysics Data System (ADS)

    Oza, Nilay; Abrahamsson, Pekka; Conboy, Kieran

    Agile methods are increasingly adopted by European companies. Academics too are conducting numerous studies on different tenets of agile methods. Companies often feel proud in marketing themselves as ‘agile’. However, the true notion of ‘being agile’ seems to have been overlooked due to lack of positioning of oneself for agility. This raises a call for more research and interactions between academia and the industry. The proposed workshop refers to this call. It will be highly relevant to participants, interested in positioning their company’s agility from organizational, group or project perspectives. The positioning of agility will help companies to better align their agile practices with stakeholder values. Results of the workshop will be shared across participants and they will also have opportunity to continue their work on agile positioning in their companies. At broader level, the work done in this workshop will contribute towards developing Agile Positioning System.

  6. Saddlepoint distribution function approximations in biostatistical inference.

    PubMed

    Kolassa, J E

    2003-01-01

    Applications of saddlepoint approximations to distribution functions are reviewed. Calculations are provided for marginal distributions and conditional distributions. These approximations are applied to problems of testing and generating confidence intervals, particularly in canonical exponential families.

  7. 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…

  8. 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

  9. 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)

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

    PubMed

    Shuttlesworth, Mary E; Zotter, Deanne

    2011-01-01

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

  11. 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.

  12. 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.

  13. 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…

  14. 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.

  15. 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,…

  16. 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…

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

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  18. 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 …

  19. 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…

  20. 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…

  1. 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…

  2. Rainbows: Mie computations and the Airy approximation.

    PubMed

    Wang, R T; van de Hulst, H C

    1991-01-01

    Efficient and accurate computation of the scattered intensity pattern by the Mie formulas is now feasible for size parameters up to x = 50,000 at least, which in visual light means spherical drops with diameters up to 6 mm. We present a method for evaluating the Mie coefficients from the ratios between Riccati-Bessel and Neumann functions of successive order. We probe the applicability of the Airy approximation, which we generalize to rainbows of arbitrary p (number of internal reflections = p - 1), by comparing the Mie and Airy intensity patterns. Millimeter size water drops show a match in all details, including the position and intensity of the supernumerary maxima and the polarization. A fairly good match is still seen for drops of 0.1 mm. A small spread in sizes helps to smooth out irrelevant detail. The dark band between the rainbows is used to test more subtle features. We conclude that this band contains not only externally reflected light (p = 0) but also a sizable contribution f rom the p = 6 and p = 7 rainbows, which shift rapidly with wavelength. The higher the refractive index, the closer both theories agree on the first primary rainbow (p = 2) peak for drop diameters as small as 0.02 mm. This may be useful in supporting experimental work. PMID:20581954

  3. 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)

  4. 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…

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

    ERIC Educational Resources Information Center

    Kingombe, Christian

    2008-01-01

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

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

    ERIC Educational Resources Information Center

    Robertson, Ray V.; Mason, Danielle

    2008-01-01

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

  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. 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

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

    PubMed

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

    2010-08-01

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

  10. A unified approach to the Darwin approximation

    SciTech Connect

    Krause, Todd B.; Apte, A.; Morrison, P. J.

    2007-10-15

    There are two basic approaches to the Darwin approximation. The first involves solving the Maxwell equations in Coulomb gauge and then approximating the vector potential to remove retardation effects. The second approach approximates the Coulomb gauge equations themselves, then solves these exactly for the vector potential. There is no a priori reason that these should result in the same approximation. Here, the equivalence of these two approaches is investigated and a unified framework is provided in which to view the Darwin approximation. Darwin's original treatment is variational in nature, but subsequent applications of his ideas in the context of Vlasov's theory are not. We present here action principles for the Darwin approximation in the Vlasov context, and this serves as a consistency check on the use of the approximation in this setting.

  11. Nucleosome positioning determinants.

    PubMed

    Fernandez, Alfonso G; Anderson, John N

    2007-08-17

    A previous report demonstrated that one site in a nucleosome assembled onto a synthetic positioning sequence known as Fragment 67 is hypersensitive to permanganate. The site is required for positioning activity and is located 1.5 turns from the dyad, which is a region of high DNA curvature in the nucleosome. Here, the permanganate sensitivity of the nucleosome positioning Fragment 601 was examined in order to expand the dataset of nucleosome sequences containing KMnO(4) hypersensitive sites. The hyperreactive T residue in the six sites detected as well as the one in Fragment 67 and three in the 5 S rDNA positioning sequence were contained within a TA step. Seven of the ten sequences were of the form CTAGPuG or the related sequence TTAAPu. These motifs were also found in the binding sites of several transcriptional regulatory proteins that kink DNA. In order to assess the significance of these sites, the 10 bp positioning determinant in Fragment 67 was removed and replaced by the nine sequences from the 5 S rDNA and Fragment 601. The results demonstrated that these derivative fragments promoted high nucleosome stability and positioning as compared to a control sequence that contained an AT step in place of the TA step. The importance of the TA step was further tested by making single base-pair substitutions in Fragment 67 and the results revealed that stability and positioning activity followed the order: TA>TG>TT>/=TC approximately GG approximately GA approximately AT. Sequences flanking the TA step were also shown to be critical for nucleosome stability and positioning. Nucleosome positioning was restored to near wild-type levels with (CTG)(3), which can form slipped stranded structures and with one base bulges that kink DNA. The results of this study suggest that local DNA structures are important for positioning and that single base-pair changes at these sites could have profound effects on those genomic functions that depend on ordered nucleosomes. PMID

  12. 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.

  13. African-American physicians' views on health reform: results of a survey.

    PubMed Central

    Byrd, W. M.; Clayton, L. A.; Kinchen, K.; Richardson, D.; Lawrence, L.; Butcher, R.; Davidson, E.

    1994-01-01

    Little is known about African-American physicians' health system experience or their opinions on health reform. In an attempt to obtain socioculturally relevant data quantifying these experiences and opinions, the National Medical Association administered a 38-question, 80-item survey instrument in August 1993. The questionnaire was completed by 236 physicians. The results indicate that African-American physicians feel health care is a right and that the health system needs fundamental change. Although there was no consensus on the type of health reform needed, approximately 35% cited availability and access to care to be the greatest problem facing the system with high costs of care (18.2%) ranking second. Unique findings in the survey indicated respondents felt that the needs and concerns of most African Americans will not be fairly addressed in the reform of the health-care system, that African-African physicians are not included in the formation of health-care policies, and that African-American physicians are facing high levels of professional and healthcare system racial discrimination. More than 99% of African-American physicians reported some degree of racial discrimination in the practice of medicine including peer review, obtaining practice privileges at hospitals, hospital staff promotions, Medicaid and Medicare reimbursements, malpractice suits, private insurance oversight and reimbursements, and referral practices of white colleagues. These findings have profound health policy, health financing, and health service delivery implications and should be included in debates and deliberations on health reform. PMID:8189452

  14. East African Rift

    NASA Technical Reports Server (NTRS)

    2008-01-01

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

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

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

  15. African fossil tali: further multivariate morphometric studies.

    PubMed

    Lisowski, F P; Albrecht, G H

    1976-07-01

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

  16. 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).

  17. 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.".

  18. 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

  19. Position indicator

    DOEpatents

    Tanner, David E.

    1981-01-01

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

  20. 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.

  1. 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.

  2. Approximate analytic solutions for singular non-linear oscillators

    NASA Technical Reports Server (NTRS)

    Bota, K. B.; Mickens, R. E.

    1984-01-01

    Mickens (1981, 1984) has considered analytic techniques for obtaining approximate solutions to one-dimensional nonlinear oscillatory systems x(double-dot) + x = lambda f(x, x/dot/, lambda) where lambda is a small positive parameter and f is a nonlinear polynomial function of its arguments. However, in certain cases there is interest in the analysis of physical systems for which the nonlinear function f(x, x/dot/, lambda) is singular for finite values of x or x(dot). The present investigation is concerned with the use of existing approximate analytic schemes to obtain solutions to singular nonlinear oscillatory differential equations.

  3. 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

  4. Approximate Analysis of Semiconductor Laser Arrays

    NASA Technical Reports Server (NTRS)

    Marshall, William K.; Katz, Joseph

    1987-01-01

    Simplified equation yields useful information on gains and output patterns. Theoretical method based on approximate waveguide equation enables prediction of lateral modes of gain-guided planar array of parallel semiconductor lasers. Equation for entire array solved directly using piecewise approximation of index of refraction by simple functions without customary approximation based on coupled waveguid modes of individual lasers. Improved results yield better understanding of laser-array modes and help in development of well-behaved high-power semiconductor laser arrays.

  5. 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.

  6. 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

  7. Positive psychotherapy.

    PubMed

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

    2006-11-01

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

  8. Positively Adolescent!

    ERIC Educational Resources Information Center

    Williamson, Sue

    2000-01-01

    Believes that music teachers should reassess their views toward adolescent behavior in the music classroom by learning to see their behavior in a positive light. Describes teaching strategies that build on four adolescent behaviors: (1) desire for peer acceptance; (2) abundant energy; (3) love of fun; and (4) limited time-managing skills. (CMK)

  9. [African histoplasmosis in a patient with HIV-2 infection].

    PubMed

    Eichmann, A; Schär, G

    1996-05-01

    9 months after immigration into Switzerland, a 38-year-old male patient from Liberia/West Africa developed granulomatous and subsequently ulcerative nodules in the face. The heterosexual patient, with no history of i.v. drug abuse, tested positive for HIV-2. Histology of a skin biopsy revealed superficial colonization by numerous fungal elements described as spores and hyphae that were compatible with the initial isolation of Candida parapsilosis. The definite diagnosis of African histoplasmosis was established 3 weeks later after review of the PAS-stained direct smear and after cultures had grown a cream-colored mold subsequently identified as Histoplasma capsulatum var. duboisii. There were no signs of disseminated disease. The lesions cleared under therapy with itraconazole (200 mg q 24h for 2 weeks, subsequently 100 mg q 24h) as well as ketoconazole and Aqua Dalibour (A. zinco-cuprica) locally for 2 months. Follow-up was not possible. Despite alarmingly increasing numbers of HIV-positive patients in Africa, the general incidence of African histoplasmosis seems to be stable with only a few cases per year. To our knowledge only four cases of disseminated African histoplasmosis have been reported in HIV-positive patients; localized cutaneous infection as in our patient, seems to be the exception. The low incidence of this infection is in contrast to the substantial number of HIV-positive patients with disseminated histoplasmosis by H. capsulatum var. capsulatum in the United States. PMID:8693301

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

    ERIC Educational Resources Information Center

    Jones, Dionne J., Ed.

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

  11. 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…

  12. Collisionless magnetic reconnection under anisotropic MHD approximation

    NASA Astrophysics Data System (ADS)

    Hirabayashi, Kota; Hoshino, Masahiro

    We study the formation of slow-mode shocks in collisionless magnetic reconnection by using one- and two-dimensional collisionless magneto-hydro-dynamic (MHD) simulations based on the double adiabatic approximation, which is an important step to bridge the gap between the Petschek-type MHD reconnection model accompanied by a pair of slow shocks and the observational evidence of the rare occasion of in-situ slow shock observation. According to our results, a pair of slow shocks does form in the reconnection layer. The resultant shock waves, however, are quite weak compared with those in an isotropic MHD from the point of view of the plasma compression and the amount of the magnetic energy released across the shock. Once the slow shock forms, the downstream plasma are heated in highly anisotropic manner and a firehose-sense (P_{||}>P_{⊥}) pressure anisotropy arises. The maximum anisotropy is limited by the marginal firehose criterion, 1-(P_{||}-P_{⊥})/B(2) =0. In spite of the weakness of the shocks, the resultant reconnection rate is kept at the same level compared with that in the corresponding ordinary MHD simulations. It is also revealed that the sequential order of propagation of the slow shock and the rotational discontinuity, which appears when the guide field component exists, changes depending on the magnitude of the guide field. Especially, when no guide field exists, the rotational discontinuity degenerates with the contact discontinuity remaining at the position of the initial current sheet, while with the slow shock in the isotropic MHD. Our result implies that the slow shock does not necessarily play an important role in the energy conversion in the reconnection system and is consistent with the satellite observation in the Earth's magnetosphere.

  13. Visual nesting impacts approximate number system estimation.

    PubMed

    Chesney, Dana L; Gelman, Rochel

    2012-08-01

    The approximate number system (ANS) allows people to quickly but inaccurately enumerate large sets without counting. One popular account of the ANS is known as the accumulator model. This model posits that the ANS acts analogously to a graduated cylinder to which one "cup" is added for each item in the set, with set numerosity read from the "height" of the cylinder. Under this model, one would predict that if all the to-be-enumerated items were not collected into the accumulator, either the sets would be underestimated, or the misses would need to be corrected by a subsequent process, leading to longer reaction times. In this experiment, we tested whether such miss effects occur. Fifty participants judged numerosities of briefly presented sets of circles. In some conditions, circles were arranged such that some were inside others. This circle nesting was expected to increase the miss rate, since previous research had indicated that items in nested configurations cannot be preattentively individuated in parallel. Logically, items in a set that cannot be simultaneously individuated cannot be simultaneously added to an accumulator. Participants' response times were longer and their estimations were lower for sets whose configurations yielded greater levels of nesting. The level of nesting in a display influenced estimation independently of the total number of items present. This indicates that miss effects, predicted by the accumulator model, are indeed seen in ANS estimation. We speculate that ANS biases might, in turn, influence cognition and behavior, perhaps by influencing which kinds of sets are spontaneously counted. PMID:22810562

  14. 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

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

    PubMed

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

    2008-12-01

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

  16. 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.

  17. Seasonal evolution of the West African heat low: a climatological perspective

    NASA Astrophysics Data System (ADS)

    Lavaysse, C.; Flamant, C.; Janicot, S.; Parker, D. J.; Lafore, J.-P.; Sultan, B.; Pelon, J.

    2009-08-01

    The West African heat low (WAHL), a region of high surface temperatures and low surface pressures, is a key element of the West African monsoon system. In this study, we propose a method to detect the WAHL in order to monitor its climatological seasonal displacement over West Africa during the period 1979-2001, using the European Centre for Medium-range Weather Forecast (ECMWF) ERA-40 reanalyses. The low-level atmospheric thickness (LLAT), a variable defined as the difference of geopotential heights at 700 and 925 hPa, is used to detect the dilatation of these levels generated by an increase of the temperature. We define grid points with 10% highest values of the LLAT as the WAHL. We show that our method reliably positions the WAHL over areas of high surface temperatures and low surface pressures, and that it is effective at detecting heat lows. In the course of the year, the climatological WAHL is shown to migrate north-westward from a position south of the Darfur mountains in the winter (November-March) to a location over the Sahara, between the Hoggar and the Atlas mountains, during the summer (June-September). The temperature tendency equation is used to investigate the processes controlling the displacement of the WAHL, and more particularly the heating at low levels. The specific period of the onset of the WAHL in its summer location over the Sahara (referred to as the Saharan heat low -SHL- onset) is also analysed during the 1984-2001 period, using complementary brightness temperature data from the European Union-funded Cloud Archive User Service (CLAUS). The climatological onset of the SHL occurs around 20 June, i.e. just before the climatological monsoon onset date. The present study suggests that the onset of the WAHL occurs approximately 5 days before the monsoon onset for the 1984-2001 period. This is confirmed independently by comparing the SHL onset date and the monsoon onset date for the 1984-2001 period. The seasonal evolution of the WAHL for the

  18. African horse sickness.

    PubMed

    Mellor, Philip Scott; Hamblin, Christopher

    2004-01-01

    African horse sickness virus (AHSV) causes a non-contagious, infectious insect-borne disease of equids and is endemic in many areas of sub-Saharan Africa and possibly Yemen in the Arabian Peninsula. However, periodically the virus makes excursions beyond its endemic areas and has at times extended as far as India and Pakistan in the east and Spain and Portugal in the west. The vectors are certain species of Culicoides biting midge the most important of which is the Afro-Asiatic species C. imicola. This paper describes the effects that AHSV has on its equid hosts, aspects of its epidemiology, and present and future prospects for control. The distribution of AHSV seems to be governed by a number of factors including the efficiency of control measures, the presence or absence of a long term vertebrate reservoir and, most importantly, the prevalence and seasonal incidence of the major vector which is controlled by climate. However, with the advent of climate-change the major vector, C. imicola, has now significantly extended its range northwards to include much of Portugal, Spain, Italy and Greece and has even been recorded from southern Switzerland. Furthermore, in many of these new locations the insect is present and active throughout the entire year. With the related bluetongue virus, which utilises the same vector species of Culicoides this has, since 1998, precipitated the worst outbreaks of bluetongue disease ever recorded with the virus extending further north in Europe than ever before and apparently becoming endemic in that continent. The prospects for similar changes in the epidemiology and distribution of AHSV are discussed.

  19. 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.

  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. African Perceptions of Female Attractiveness

    PubMed Central

    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. PMID:23144734

  2. 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.

  3. 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.

  4. West African crude production diversifies

    SciTech Connect

    Aalund, L.

    1983-06-01

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

  5. 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.

  6. Novel bivariate moment-closure approximations.

    PubMed

    Krishnarajah, Isthrinayagy; Marion, Glenn; Gibson, Gavin

    2007-08-01

    Nonlinear stochastic models are typically intractable to analytic solutions and hence, moment-closure schemes are used to provide approximations to these models. Existing closure approximations are often unable to describe transient aspects caused by extinction behaviour in a stochastic process. Recent work has tackled this problem in the univariate case. In this study, we address this problem by introducing novel bivariate moment-closure methods based on mixture distributions. Novel closure approximations are developed, based on the beta-binomial, zero-modified distributions and the log-Normal, designed to capture the behaviour of the stochastic SIS model with varying population size, around the threshold between persistence and extinction of disease. The idea of conditional dependence between variables of interest underlies these mixture approximations. In the first approximation, we assume that the distribution of infectives (I) conditional on population size (N) is governed by the beta-binomial and for the second form, we assume that I is governed by zero-modified beta-binomial distribution where in either case N follows a log-Normal distribution. We analyse the impact of coupling and inter-dependency between population variables on the behaviour of the approximations developed. Thus, the approximations are applied in two situations in the case of the SIS model where: (1) the death rate is independent of disease status; and (2) the death rate is disease-dependent. Comparison with simulation shows that these mixture approximations are able to predict disease extinction behaviour and describe transient aspects of the process.

  7. 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…

  8. 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.

  9. Diagonal Pade approximations for initial value problems

    SciTech Connect

    Reusch, M.F.; Ratzan, L.; Pomphrey, N.; Park, W.

    1987-06-01

    Diagonal Pade approximations to the time evolution operator for initial value problems are applied in a novel way to the numerical solution of these problems by explicitly factoring the polynomials of the approximation. A remarkable gain over conventional methods in efficiency and accuracy of solution is obtained. 20 refs., 3 figs., 1 tab.

  10. Kernel polynomial approximations for densities of states and spectral functions

    SciTech Connect

    Silver, R.N.; Voter, A.F.; Kress, J.D.; Roeder, H.

    1996-03-01

    Chebyshev polynomial approximations are an efficient and numerically stable way to calculate properties of the very large Hamiltonians important in computational condensed matter physics. The present paper derives an optimal kernal polynomial which enforces positivity of density of states and spectral estimates, achieves the best energy resolution, and preserves normalization. This kernel polynomial method (KPM) is demonstrated for electronic structure and dynamic magnetic susceptibility calculations. For tight binding Hamiltonians of Si, we show how to achieve high precision and rapid convergence of the cohesive energy and vacancy formation energy by careful attention to the order of approximation. For disordered XXZ-magnets, we show that the KPM provides a simpler and more reliable procedure for calculating spectral functions than Lanczos recursion methods. Polynomial approximations to Fermi projection operators are also proposed. 26 refs., 10 figs.

  11. Position sensor

    NASA Technical Reports Server (NTRS)

    Auer, Siegfried (Inventor)

    1988-01-01

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

  12. 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

  13. The African American Image in American Cinema.

    ERIC Educational Resources Information Center

    Bourne, St. Clair

    1990-01-01

    Political conditions have influenced the screen images of U.S. cinema, and the images of African Americans have reflected prevailing social stereotypes. The history of African-American representation in films is traced, and it is noted that the tendency to portray African Americans stereotypically has not changed. (SLD)

  14. 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)

  15. 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…

  16. 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…

  17. 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,…

  18. The Economic Question and the African Novel.

    ERIC Educational Resources Information Center

    Okonkwo, J. I.

    1989-01-01

    Presents examples of how African novelists express their ideas on the restructuring of African economic orders and the social and political implications that emanate from them. Discusses the present state of the African economy reflected in the visions of these writers, and their visions of future socio-economic health of Africa. (JS)

  19. Content-based Instruction for African Languages.

    ERIC Educational Resources Information Center

    Moshi, Lioba

    2001-01-01

    Examines content-based instruction for African languages and considers Schleicher's (2000) expatiation of goal-based instruction for African languages. Focuses on the parameters for content-based instruction, the profile of a content-based instructional program, the nature of content-based instruction, the first steps for African languages, and…

  20. Complex Syntax Production of African American Preschoolers.

    ERIC Educational Resources Information Center

    Jackson, Sandra C.; Roberts, Joanne E.

    2001-01-01

    This study examined changes in the complex syntax production of 85 African American preschoolers and the role of child (gender, age, African American English) and family (home environment) factors. Age, gender, and home environment effects were found for the amount of complex language used. African American English was not related to amount of…

  1. Approximate error conjugation gradient minimization methods

    DOEpatents

    Kallman, Jeffrey S

    2013-05-21

    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  2. Approximate Shortest Path Queries Using Voronoi Duals

    NASA Astrophysics Data System (ADS)

    Honiden, Shinichi; Houle, Michael E.; Sommer, Christian; Wolff, Martin

    We propose an approximation method to answer point-to-point shortest path queries in undirected edge-weighted graphs, based on random sampling and Voronoi duals. We compute a simplification of the graph by selecting nodes independently at random with probability p. Edges are generated as the Voronoi dual of the original graph, using the selected nodes as Voronoi sites. This overlay graph allows for fast computation of approximate shortest paths for general, undirected graphs. The time-quality tradeoff decision can be made at query time. We provide bounds on the approximation ratio of the path lengths as well as experimental results. The theoretical worst-case approximation ratio is bounded by a logarithmic factor. Experiments show that our approximation method based on Voronoi duals has extremely fast preprocessing time and efficiently computes reasonably short paths.

  3. 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…

  4. 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.

  5. Évidences paléomagnétiques et paléontologiques en faveur d'une position antipodale du craton Ouest-Africain et de la Chine du Nord : conséquences paléogéographiquesPalaeomagnetic and palaeontologic evidence for an antipodal position of the West African Craton and of northern China in the Rodinia puzzle: palaeogeographic consequences

    NASA Astrophysics Data System (ADS)

    Lefort, Jean-Pierre; Aı̈fa, Tahar; Bourrouilh, Robert

    2004-02-01

    Reappraisal of the palaeomagnetic data previously published about the West African Craton and their comparison with the most recent information obtained on doleritic dykes and stromatolite-bearing formations allow us to propose, after a critical examination of the old geochronological data, a new path for the West African Craton between 2200 and 700 Ma. This path has been compared with that of eastern China (which can be simply divided into a northern and a southern China block) between 1400 and 700 Ma. We can observe that these two blocks show a common path before their accretion to the Rodinia super-continent. These two blocks, which were located close the equator and at the outboard of Rodinia at about 1000 Ma, were also characterized by identical stromatolitic assemblages. This result shows that West Africa and Eastern China represented the antipodal continental margins of Rodinia. One can also deduce from our data that the accretion of Rodinia mainly resulted from north-south-oriented displacements. To cite this article: J.-P. Lefort et al., C. R. Geoscience 336 (2004).

  6. 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…

  7. 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…

  8. 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…

  9. Charged point defects in semiconductors and the supercell approximation

    NASA Astrophysics Data System (ADS)

    Lento, J.; Mozos, J.-L.; Nieminen, R. M.

    2002-03-01

    The effects of the supercell approximation in first-principles calculations for isolated, charged point defects in semiconductors and insulators are studied. The convergence of the Coulomb energy with respect to the supercell size is investigated. Quantitative numerical results for the standard uniform compensating charge and the newly proposed localized compensating charge scheme are presented for a prototypical defect, the doubly positive silicon self-interstitial.

  10. 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.

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

    PubMed Central

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

    2014-01-01

    Achievement of a coherent and strong sense of self is critical to positive academic outcomes for urban minority youth. The present study utilized a mixed-methods approach to explore key aspects of identity development for African American adolescents living in a high-poverty, urban neighborhood. Results suggest that efforts to develop a sense of oneself as an individual and in relation to the world are impeded by mixed messages on African American culture and achievement. Findings are discussed in the context of teaching and working with urban African American adolescents in a way that promotes positive identity development. PMID:25485041

  13. PUBLISHING SOUTH AFRICAN SCHOLARSHIP IN THE GLOBAL ACADEMIC COMMUNITY.

    PubMed

    Le Roux, Elizabeth

    2015-09-20

    South Africa's academic publishing history has been profoundly influenced by its colonial heritage. This is reflected in the publication of Transactions of the South African Philosophical Society (later, the Royal Society of South Africa) from 1878. Although the Society and journal sought to promote original research about South Africa, it was modelled after the Royal Society in London and formed part of an imperial scientific community. As the local higher education institutions grew more independent and research-focused, local scholarly publishing developed as well, with university presses playing an increasingly important role. The University of South Africa (Unisa) Press started publishing departmental journals in the 1950s, with a focus on journals that 'speak to the student', and it is today the only South African university press with an active journals publishing programme. As external funding declined and the country became intellectually isolated in the high apartheid period, the Press managed to attract journals that could no longer be subsidized by learned societies and other universities. More recently, new co-publishing arrangements have brought South African journals back into an international intellectual community. Although some argue that this constitutes a re-colonization of South African knowledge production, it is also an innovative strategy for positioning local research in a global context.

  14. PUBLISHING SOUTH AFRICAN SCHOLARSHIP IN THE GLOBAL ACADEMIC COMMUNITY.

    PubMed

    Le Roux, Elizabeth

    2015-09-20

    South Africa's academic publishing history has been profoundly influenced by its colonial heritage. This is reflected in the publication of Transactions of the South African Philosophical Society (later, the Royal Society of South Africa) from 1878. Although the Society and journal sought to promote original research about South Africa, it was modelled after the Royal Society in London and formed part of an imperial scientific community. As the local higher education institutions grew more independent and research-focused, local scholarly publishing developed as well, with university presses playing an increasingly important role. The University of South Africa (Unisa) Press started publishing departmental journals in the 1950s, with a focus on journals that 'speak to the student', and it is today the only South African university press with an active journals publishing programme. As external funding declined and the country became intellectually isolated in the high apartheid period, the Press managed to attract journals that could no longer be subsidized by learned societies and other universities. More recently, new co-publishing arrangements have brought South African journals back into an international intellectual community. Although some argue that this constitutes a re-colonization of South African knowledge production, it is also an innovative strategy for positioning local research in a global context. PMID:26495579

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Frankenstein's glue: transition functions for approximate solutions

    NASA Astrophysics Data System (ADS)

    Yunes, Nicolás

    2007-09-01

    Approximations are commonly employed to find approximate solutions to the Einstein equations. These solutions, however, are usually only valid in some specific spacetime region. A global solution can be constructed by gluing approximate solutions together, but this procedure is difficult because discontinuities can arise, leading to large violations of the Einstein equations. In this paper, we provide an attempt to formalize this gluing scheme by studying transition functions that join approximate analytic solutions together. In particular, we propose certain sufficient conditions on these functions and prove that these conditions guarantee that the joined solution still satisfies the Einstein equations analytically to the same order as the approximate ones. An example is also provided for a binary system of non-spinning black holes, where the approximate solutions are taken to be given by a post-Newtonian expansion and a perturbed Schwarzschild solution. For this specific case, we show that if the transition functions satisfy the proposed conditions, then the joined solution does not contain any violations to the Einstein equations larger than those already inherent in the approximations. We further show that if these functions violate the proposed conditions, then the matter content of the spacetime is modified by the introduction of a matter shell, whose stress energy tensor depends on derivatives of these functions.

  2. Correlation chart of Pennsylvanian rocks in Alabama, Tennessee, Kentucky, Virginia, West Virginia, Ohio, Maryland, and Pennsylvania showing approximate position of coal beds, coal zones, and key stratigraphic units: Chapter D.2 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    USGS Publications Warehouse

    Ruppert, Leslie F.; Trippi, Michael H.; Slucher, Ernie R.; Ruppert, Leslie F.; Ryder, Robert T.

    2014-01-01

    In other regions of the basin, group and formation boundaries are more difficult to identify over extensive areas. One example is the placement of the contact between the New River Formation and the overlying Kanawha Formation—a boundary that is not easily defined beyond the area where these units were first defined in West Virginia. At the type section of the Kanawha Formation, the base of the Lower Douglas coal zone (fig. 1) defines the contact between the Kanawha Formation and the underlying New River Formation (Rice and others, 1994b). However, subsequent mapping has demonstrated that the Lower Douglas coal zone is regionally discontinuous and in many parts of West Virginia is absent (Blake and others, 2002). Where absent, the Nuttall Sandstone Member of the underlying New River Formation sometimes occurs in the stratigraphic position of the Lower Douglas coal zone. Yet, even the Nuttall Sandstone Member has been found to be regionally discontinuous and of varying thickness throughout its extent, features that hinder its u

  3. Approximate knowledge compilation: The first order case

    SciTech Connect

    Val, A. del

    1996-12-31

    Knowledge compilation procedures make a knowledge base more explicit so as make inference with respect to the compiled knowledge base tractable or at least more efficient. Most work to date in this area has been restricted to the propositional case, despite the importance of first order theories for expressing knowledge concisely. Focusing on (LUB) approximate compilation, our contribution is twofold: (1) We present a new ground algorithm for approximate compilation which can produce exponential savings with respect to the previously known algorithm. (2) We show that both ground algorithms can be lifted to the first order case preserving their correctness for approximate compilation.

  4. 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.

  5. 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.

  6. 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.

  7. 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…

  8. Racial Pride and Religiosity among African American Boys: Implications for Academic Motivation and Achievement

    ERIC Educational Resources Information Center

    Butler-Barnes, Sheretta T.; Williams, Terrinieka T.; Chavous, Tabbye M.

    2012-01-01

    The persistent underachievement among African American boys has led to increased empirical inquiry, yet little research considers within-group variation in achievement nor positive youth characteristics that help explain positive achievement outcomes. This study conceptualized culturally-based factors (racial pride and religiosity) as adolescent…

  9. Colonialism, Biko and AIDS: reflections on the principle of beneficence in South African medical ethics.

    PubMed

    Braude, Hillel David

    2009-06-01

    This paper examines the principle of beneficence in the light of moral and epistemological concerns that have crystallized in the South African context around clinical care. Three examples from the South African experience affecting the development of bioethics are examined: medical colonialism, the death in detention of Steve Biko, and the HIV/AIDS epidemic. Michael Gelfand's book [(1948). The sick African: a clinical study. Cape Town: Stewart Printing Company.] on African medical conditions captures the ambiguous nature of colonial medicine that linked genuine medical treatment with the civilizing mission. Biko's death was a key historical event that deeply implicated the medical profession under apartheid. The present HIV/AIDS epidemic presents the gravest social and political crisis for South African society. All three experiences influence the meaning and relevance of beneficence as a bioethics principle in the South African context. This paper argues for a South African bioethics informed by a critical humanism that takes account of the colonial past, and that does not model itself on an "original wound" or negation, but on positive care-giving practices.

  10. Low-income African American women's beliefs regarding exercise during pregnancy.

    PubMed

    Krans, Elizabeth E; Chang, Judy C

    2012-08-01

    Exercise may decrease the incidence of obesity and obesity related complications during pregnancy including gestational diabetes and preeclampsia. African American women are at higher risk for obesity and physical inactivity during pregnancy when compared to other patient groups. The purpose of this qualitative study was to describe in detail the unique beliefs and perspectives regarding exercise during pregnancy of African American women. A series of 6 focus groups discussions with pregnant African American women were audio-recorded and transcribed verbatim. Focus group transcripts were qualitatively analyzed for major themes and independently coded for beliefs regarding exercise during pregnancy. A total of 34 pregnant, African American women participated in 6 focus group discussions. The majority of women were single (94%), had only a high school education (67%), received Medicaid (100%) and had a mean BMI of 33 kg/m(2). Three major themes emerged regarding our subjects' beliefs about exercise during pregnancy: (1) women had a broad definition of what types of activities constituted exercise, (2) women believed exercise was generally beneficial during pregnancy and (3) women believed certain types of activities or movements could cause problems with pregnancy. African American women overwhelmingly believe that exercise positively impacts pregnancy. A lack of knowledge concerning the benefits of exercise during pregnancy was not found to be a major contributor to inactivity in African American women. However, health care providers should be aware of cultural myths that prevent many African American women from performing certain activities during pregnancy.

  11. Classic African American Children's Literature

    ERIC Educational Resources Information Center

    McNair, Jonda C.

    2010-01-01

    The purpose of this article is to assert that there are classic African American children's books and to identify a sampling of them. The author presents multiple definitions of the term classic based on the responses of children's literature experts and relevant scholarship. Next, the manner in which data were collected and analyzed in regard to…

  12. 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…

  13. Liberia: America's Closest African Ally.

    ERIC Educational Resources Information Center

    Thompson, Samuel; Mowell, Barry

    1997-01-01

    Profiles Liberia, the West African nation patterned after the United States and colonized with freed U.S. slaves in the early 19th century. Reviews the country's history and its eruption into civil strife in 1990, showing how tensions have often characterized relationships between Liberians of different ethnic identities. (MJP)

  14. 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)

  15. 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…

  16. Developing anatomical terms in an African language.

    PubMed

    Madzimbamuto, Farai Daniel

    2012-03-01

    Clinical and technical information imparted in most African languages involves inexact terminology and code switching, so it lacks the explanatory power characterised by the English language. African languages are absent in the tertiary science education environment and forums where African scientists could present scientific material in the medium of African languages. This limits the development of African languages in the scientific domain. There has recently been a trend in several African languages to develop and intellectualise them, especially in the field of medical sciences. The ChiShona language is used to explore the ability of an African language to develop new terminology, to name the vertebral skeleton and describe it scientifically. It uses word compounding to demonstrate terminology development. ChiShona has similarities with several hundred other Bantu languages in East, Central and Southern Africa. Advancing this language can promote similar developments in others, making them more explanatory for the lay public and health professionals. PMID:22380900

  17. Adiabatic approximation for the density matrix

    NASA Astrophysics Data System (ADS)

    Band, Yehuda B.

    1992-05-01

    An adiabatic approximation for the Liouville density-matrix equation which includes decay terms is developed. The adiabatic approximation employs the eigenvectors of the non-normal Liouville operator. The approximation is valid when there exists a complete set of eigenvectors of the non-normal Liouville operator (i.e., the eigenvectors span the density-matrix space), the time rate of change of the Liouville operator is small, and an auxiliary matrix is nonsingular. Numerical examples are presented involving efficient population transfer in a molecule by stimulated Raman scattering, with the intermediate level of the molecule decaying on a time scale that is fast compared with the pulse durations of the pump and Stokes fields. The adiabatic density-matrix approximation can be simply used to determine the density matrix for atomic or molecular systems interacting with cw electromagnetic fields when spontaneous emission or other decay mechanisms prevail.

  18. 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.

  19. 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.

  20. Linear Approximation SAR Azimuth Processing Study

    NASA Technical Reports Server (NTRS)

    Lindquist, R. B.; Masnaghetti, R. K.; Belland, E.; Hance, H. V.; Weis, W. G.

    1979-01-01

    A segmented linear approximation of the quadratic phase function that is used to focus the synthetic antenna of a SAR was studied. Ideal focusing, using a quadratic varying phase focusing function during the time radar target histories are gathered, requires a large number of complex multiplications. These can be largely eliminated by using linear approximation techniques. The result is a reduced processor size and chip count relative to ideally focussed processing and a correspondingly increased feasibility for spaceworthy implementation. A preliminary design and sizing for a spaceworthy linear approximation SAR azimuth processor meeting requirements similar to those of the SEASAT-A SAR was developed. The study resulted in a design with approximately 1500 IC's, 1.2 cubic feet of volume, and 350 watts of power for a single look, 4000 range cell azimuth processor with 25 meters resolution.

  1. 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

  2. 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.

  3. Introduction to the Maxwell Garnett approximation: tutorial.

    PubMed

    Markel, Vadim A

    2016-07-01

    This tutorial is devoted to the Maxwell Garnett approximation and related theories. Topics covered in this first, introductory part of the tutorial include the Lorentz local field correction, the Clausius-Mossotti relation and its role in the modern numerical technique known as the discrete dipole approximation, the Maxwell Garnett mixing formula for isotropic and anisotropic media, multicomponent mixtures and the Bruggeman equation, the concept of smooth field, and Wiener and Bergman-Milton bounds. PMID:27409680

  4. The Actinide Transition Revisited by Gutzwiller Approximation

    NASA Astrophysics Data System (ADS)

    Xu, Wenhu; Lanata, Nicola; Yao, Yongxin; Kotliar, Gabriel

    2015-03-01

    We revisit the problem of the actinide transition using the Gutzwiller approximation (GA) in combination with the local density approximation (LDA). In particular, we compute the equilibrium volumes of the actinide series and reproduce the abrupt change of density found experimentally near plutonium as a function of the atomic number. We discuss how this behavior relates with the electron correlations in the 5 f states, the lattice structure, and the spin-orbit interaction. Our results are in good agreement with the experiments.

  5. 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.

  6. 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.

  7. Approximate Solutions Of Equations Of Steady Diffusion

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1992-01-01

    Rigorous analysis yields reliable criteria for "best-fit" functions. Improved "curve-fitting" method yields approximate solutions to differential equations of steady-state diffusion. Method applies to problems in which rates of diffusion depend linearly or nonlinearly on concentrations of diffusants, approximate solutions analytic or numerical, and boundary conditions of Dirichlet type, of Neumann type, or mixture of both types. Applied to equations for diffusion of charge carriers in semiconductors in which mobilities and lifetimes of charge carriers depend on concentrations.

  8. 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.

  9. Assessment of differences in HLA-A, -B, and -DRB1 allele mismatches among African-American and non-African-American recipients of deceased kidney transplants.

    PubMed

    Kamoun, M; Israni, A K; Joffe, M M; Hoy, T; Kearns, J; Mange, K C; Feldman, D; Goodman, N; Rosas, S E; Abrams, J D; Brayman, K L; Feldman, H I

    2007-01-01

    Among recipients of deceased donor kidney transplants, African-Americans experience a more rapid rate of kidney allograft loss than non-African-Americans. The purpose of this study was to characterize and quantify the HLA-A, -B, and -DRB1 allele mismatches and amino acid substitutions at antigen recognition sites among African-American and non-African-American recipients of deceased donor kidney transplants matched at the antigen level. In recipients with zero HLA antigen mismatches, the degree of one or two HLA allele mismatches for both racial groups combined was 47%, 29%, and 11% at HLA-DRB1, HLA-B, and HLA-A, respectively. There was a greater number of allele mismatches in African-Americans than non-African-Americans at HLA-A (P < .0001), -B (P = .096), and -DRB1 loci (P < .0001). For both racial groups, the HLA allele mismatches were predominantly at A2 for HLA-A; B35 and B44 for HLA-B; but multiple specificities for HLA-DRB1. The observed amino acid mismatches were concentrated at a few functional positions in the antigen binding site of HLA-A and -B and -DRB1 molecules. Future studies are ongoing to assess the impact of these HLA mismatches on kidney allograft loss.

  10. Creating a segregated medical profession: African American physicians and organized medicine, 1846-1910.

    PubMed

    Baker, Robert B; Washington, Harriet A; Olakanmi, Ololade; Savitt, Todd L; Jacobs, Elizabeth A; Hoover, Eddie; Wynia, Matthew K; Blanchard, Janice; Boulware, L Ebony; Braddock, Clarence; Corbie-Smith, Giselle; Crawley, LaVera; LaVeist, Thomas A; Maxey, Randall; Mills, Charles; Moseley, Kathryn L; Williams, David R

    2009-06-01

    An independent panel of experts, convened by the American Medical Association (AMA) Institute for Ethics, analyzed the roots of the racial divide within American medical organizations. In this, the first of a 2-part report, we describe 2 watershed moments that helped institutionalize the racial divide. The first occurred in the 1870s, when 2 medical societies from Washington, DC, sent rival delegations to the AMA's national meetings: an all-white delegation from a medical society that the US courts and Congress had formally censured for discriminating against black physicians; and an integrated delegation from a medical society led by physicians from Howard University. Through parliamentary maneuvers and variable enforcement of credentialing standards, the integrated delegation was twice excluded from the AMA's meetings, while the all-white society's delegations were admitted. AMA leaders then voted to devolve the power to select delegates to state societies, thereby accepting segregation in constituent societies and forcing African American physicians to create their own, separate organizations. A second watershed involved AMA-promoted educational reforms, including the 1910 Flexner report. Straightforwardly applied, the report's population-based criterion for determining the need for phySicians would have recommended increased training of African American physicians to serve the approximately 9 million African Americans in the segregated south. Instead, the report recommended closing all but 2 African American medical schools, helping to cement in place an African American educational system that was separate, unequal, and destined to be insufficient to the needs of African Americans nationwide. PMID:19585918

  11. Motivational interviewing to reduce cardiovascular risk in African American and Latina women.

    PubMed

    Witt, Dawn R; Lindquist, Ruth; Treat-Jacobson, Diane; Boucher, Jackie L; Konety, Suma H; Savik, Kay

    2013-11-01

    Cardiovascular disease (CVD) is the leading cause of death for women, and disproportionally so for African American and Latina women. CVD is largely preventable and many risks can be attributable to health behaviors, implementing and sustaining positive health behaviors is a challenge. Motivational interviewing is one promising intervention for initiating behavior change. The purpose of this review was to identify, synthesize, and critically analyze the existing literature on the use of motivational interviewing as a behavioral intervention to reduce CVD risk among African American and Latina women. Seven studies were identified that met inclusion criteria. Results of this review suggest that motivational interviewing has mixed results when used to reduce cardiovascular risk factors in African American and Latina women. More research using a standardized motivational interviewing approach is needed to definitively determine if it is an effective behavioral intervention to reduce CVD risk when used in populations of African American and Latina women.

  12. Periaortic haemangiosarcoma in an African wild dog (Lycaon pictus).

    PubMed

    Newell-Fugate, A; Lane, E

    2009-06-01

    A 9-year-old apparently healthy male African wild dog (Lycaon pictus) was found dead in its enclosure at the De Wildt Cheetah and Wildlife Centre. Necropsy revealed a pericardium distended by approximately 250 ml of thick blood. A soft, red, lobulated mass was attached to the periaortic fat between the level of the aortic valves and the pericardial reflection. Histologically, the mass was consistent with a haemangiosarcoma. Other findings in the heart included mild to moderate ventricular hypertrophy and moderate, acute perivascular myocardial necrosis. Sudden death was attributed to acute heart failure precipitated by cardiac tamponade.

  13. HIV stigma and discrimination in medical settings: stories from African women in New Zealand.

    PubMed

    Cannon Poindexter, Cynthia

    2013-01-01

    Recent changes in New Zealand's HIV and immigration situations have sparked a need to understand the experiences of HIV-positive African newcomers there. Here a narrative lens was brought to a previous qualitative study to harvest stories about discrimination in medical settings in New Zealand, told by four HIV-positive African women. Despite describing positive experiences with specialist HIV providers, their accounts shed light on weaknesses within the health care system regarding the rights and treatment of immigrants living with HIV. Participants reported inappropriate use of universal precautions, violations of confidentiality rights, discriminatory comments about Africans or persons with HIV, and misinformation about HIV transmission. Interventions must include enforcement of The Privacy Law and consistent training and monitoring of employee behavior in health care organizations. PMID:24028736

  14. HIV stigma and discrimination in medical settings: stories from African women in New Zealand.

    PubMed

    Cannon Poindexter, Cynthia

    2013-01-01

    Recent changes in New Zealand's HIV and immigration situations have sparked a need to understand the experiences of HIV-positive African newcomers there. Here a narrative lens was brought to a previous qualitative study to harvest stories about discrimination in medical settings in New Zealand, told by four HIV-positive African women. Despite describing positive experiences with specialist HIV providers, their accounts shed light on weaknesses within the health care system regarding the rights and treatment of immigrants living with HIV. Participants reported inappropriate use of universal precautions, violations of confidentiality rights, discriminatory comments about Africans or persons with HIV, and misinformation about HIV transmission. Interventions must include enforcement of The Privacy Law and consistent training and monitoring of employee behavior in health care organizations.

  15. 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.

  16. Multi Scale Imaging of Seismic Structure beneath the Western Branch of the East-African Rift

    NASA Astrophysics Data System (ADS)

    Jakovlev, A.; Rumpker, G.; Koulakov, I.

    2010-12-01

    In this study, we investigate the crustal and upper mantle velocity structure beneath the East African Rift System (EARS) as a whole and beneath the Rwenzori Mountains in western Uganda in particular. The most interesting features here is the mountain range of approximately 50 km-wide, with a length of about 150 km, which is situated within the western branch of the East African rift zone and reaches the altitudes of more than 5000 m. The joint tomographic inversion was used to investigate the velocity structure beneath the Rwenzoris on a local scale down to the depth of about 75 - 80 km. Arrival times from 2053 local and 284 teleseismic earthquakes recorded by a temporary network equipped 35 short period and broad-band stations were used as an input for the joint tomographic inversion. The network is covering an area of 140×90 km2. To estimate resolution ability and stability of the obtained results we performed many different tests. The tests show that the best horizontal resolution is achieved in the northern part of the study area, where the density of the ray coverage is highest. In shallow depths where local earthquake rays dominate, the vertical and horizontal resolution is relatvely high, while in deeper sections covered with teleseismic rays, the anomalies seem to be strongly smeared and can be interpreted only on a qualitative level. Velocity structure in the upper crust agrees with the distribution of the main geological units, such as sedimentary basins, igneous outcrops, thermal fields etc. For the uppermost mantle, our results reveal an inclined boundary between the high-velocity Tanzania craton and low-velocity patterns beneath the rift. The same position of the contact between craton and rift zone was obtained in the regional tomographic study of the EARS as a whole. This regional study was based on the ISC data, which contains information about arrival times of signals from earthquakes at more than 7000 stations of the global seismological network

  17. 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

  18. Coming of Age: African American Male Rites-of-Passage.

    ERIC Educational Resources Information Center

    Hill, Paul, Jr.

    An overview is provided of issues confronting the African American male, along with a strategy to nurture a new generation of African American males. Chapters 1 and 2 focus on the social status and new demographics of the African American male and the external threats that are devastating to the African American male and the African American…

  19. Social class and heart disease mortality among African Americans.

    PubMed

    Barnett, Elizabeth; Williams, Carol R; Moore, Latetia; Chen, Fangfei

    2002-01-01

    The purpose of the present study was to examine variation in heart disease death rates by the social class of decedents. The term, "social class" refers to a complex set of phenomena such as control over economic resources, social status, and power relative to others in society. The target population for this study was African-American adults aged 35-74 years old who resided in the United States during the years 1996-1997. As a proxy for social class, we examined 5 levels of educational attainment: 0-8 years of school completed (Social Class I), 9-11 years of school completed (Social Class II), high school graduate/12 years of school completed (Social Class III), some college completed (Social Class IV), and college degree completed (Social Class V). Older age, male gender, and lower social class were all independently associated with higher heart disease death rates. For all ages, more disadvantaged social classes had a higher risk of heart disease mortality. The highest relative risks were found for Social Classes I and II among the younger age groups. Many of the "prerequisites" for the "heart healthy lifestyle" are predicated on the benefits of a privileged social class position. For African Americans, there are the additional stressors of segregation, exclusion, and discrimination to overcome, as well as the cumulative physiological toll of lifetime resistance to various forms of racism. For many African Americans in disadvantaged social class positions, the obstacles to reducing the risk for heart disease are very difficult to overcome.

  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. 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.

  2. 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.

  3. Violation of the condon approximation in semiconducting carbon nanotubes.

    PubMed

    Duque, Juan G; Chen, Hang; Swan, Anna K; Shreve, Andrew P; Kilina, Svetlana; Tretiak, Sergei; Tu, Xiaomin; Zheng, Ming; Doorn, Stephen K

    2011-06-28

    The Condon approximation is widely applied in molecular and condensed matter spectroscopy and states that electronic transition dipoles are independent of nuclear positions. This approximation is related to the Franck-Condon principle, which in its simplest form holds that electronic transitions are instantaneous on the time scale of nuclear motion. The Condon approximation leads to a long-held assumption in Raman spectroscopy of carbon nanotubes: intensities arising from resonance with incident and scattered photons are equal. Direct testing of this assumption has not been possible due to the lack of homogeneous populations of specific carbon nanotube chiralities. Here, we present the first complete Raman excitation profiles (REPs) for the nanotube G band for 10 pure semiconducting chiralities. In contrast to expectations, a strong asymmetry is observed in the REPs for all chiralities, with the scattered resonance always appearing weaker than the incident resonance. The observed behavior results from violation of the Condon approximation and originates in changes in the electronic transition dipole due to nuclear motion (non-Condon effect), as confirmed by our quantum chemical calculations. The agreement of our calculations with the experimental REP asymmetries and observed trends in family dependence indicates the behavior is intrinsic. PMID:21612303

  4. Temperature dependence of electronic eigenenergies in the adiabatic harmonic approximation

    NASA Astrophysics Data System (ADS)

    Poncé, S.; Antonius, G.; Gillet, Y.; Boulanger, P.; Laflamme Janssen, J.; Marini, A.; Côté, M.; Gonze, X.

    2014-12-01

    The renormalization of electronic eigenenergies due to electron-phonon interactions (temperature dependence and zero-point motion effect) is important in many materials. We address it in the adiabatic harmonic approximation, based on first principles (e.g., density-functional theory), from different points of view: directly from atomic position fluctuations or, alternatively, from Janak's theorem generalized to the case where the Helmholtz free energy, including the vibrational entropy, is used. We prove their equivalence, based on the usual form of Janak's theorem and on the dynamical equation. We then also place the Allen-Heine-Cardona (AHC) theory of the renormalization in a first-principles context. The AHC theory relies on the rigid-ion approximation, and naturally leads to a self-energy (Fan) contribution and a Debye-Waller contribution. Such a splitting can also be done for the complete harmonic adiabatic expression, in which the rigid-ion approximation is not required. A numerical study within the density-functional perturbation theory framework allows us to compare the AHC theory with frozen-phonon calculations, with or without the rigid-ion approximation. For the two different numerical approaches without non-rigid-ion terms, the agreement is better than 7 μ eV in the case of diamond, which represent an agreement to five significant digits. The magnitude of the non-rigid-ion terms in this case is also presented, distinguishing specific phonon modes contributions to different electronic eigenenergies.

  5. 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.

  6. 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.

  7. Approximate formulas for moderately small eikonal amplitudes

    NASA Astrophysics Data System (ADS)

    Kisselev, A. V.

    2016-08-01

    We consider the eikonal approximation for moderately small scattering amplitudes. To find numerical estimates of these approximations, we derive formulas that contain no Bessel functions and consequently no rapidly oscillating integrands. To obtain these formulas, we study improper integrals of the first kind containing products of the Bessel functions J0(z). We generalize the expression with four functions J0(z) and also find expressions for the integrals with the product of five and six Bessel functions. We generalize a known formula for the improper integral with two functions Jυ (az) to the case with noninteger υ and complex a.

  8. ANALOG QUANTUM NEURON FOR FUNCTIONS APPROXIMATION

    SciTech Connect

    A. EZHOV; A. KHROMOV; G. BERMAN

    2001-05-01

    We describe a system able to perform universal stochastic approximations of continuous multivariable functions in both neuron-like and quantum manner. The implementation of this model in the form of multi-barrier multiple-silt system has been earlier proposed. For the simplified waveguide variant of this model it is proved, that the system can approximate any continuous function of many variables. This theorem is also applied to the 2-input quantum neural model analogical to the schemes developed for quantum control.

  9. Approximate controllability of nonlinear impulsive differential systems

    NASA Astrophysics Data System (ADS)

    Sakthivel, R.; Mahmudov, N. I.; Kim, J. H.

    2007-08-01

    Many practical systems in physical and biological sciences have impulsive dynamical be- haviours during the evolution process which can be modeled by impulsive differential equations. This paper studies the approximate controllability issue for nonlinear impulsive differential and neutral functional differential equations in Hilbert spaces. Based on the semigroup theory and fixed point approach, sufficient conditions for approximate controllability of impulsive differential and neutral functional differential equations are established. Finally, two examples are presented to illustrate the utility of the proposed result. The results improve some recent results.

  10. 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

  11. 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…

  12. 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,…

  13. 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…

  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. Recurrent sebaceous carcinoma in an African hedgehog (Atelerix albiventris).

    PubMed

    Kim, Hyung-Jin; Kim, Yong-Baek; Park, Jun-Won; Oh, Won-Seok; Kim, Eun-Ok; Lim, Byoung-Yong; Kim, Dae-Yong

    2010-07-01

    A 1.5-year-old intact male African hedgehog (Atelerix albiventris) was presented with a firm, non-movable subcutaneous mass on ventral chest area. Microscopically, the tumor was un-encapsulated, invasive up to the muscle layer, and composed of highly pleomorphic polygonal cells arranged in variably-sized lobules. The neoplastic cells had abundant cytoplasm with vacuolation and a large pleomorphic nucleus with prominent nucleoli. Mitotic figures were frequently observed with atypical mitoses. Immunohistochemically, the neoplastic cells were strongly positive for cytokeratin, but negative for vimentin. Based on these findings, a diagnosis of sebaceous carcinoma was made. Three months after the surgery, a recurrent mass was found at the surgical site. On necropsy, the mass has penetrated the underlying intercostal musculature, without metastasis to distant organs. This is the first report of a sebaceous carcinoma in an African hedgehog.

  17. 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. PMID:16643100

  18. Digital expression among urban, low-income African American adolescents.

    PubMed

    Baker, Christina M; Staiano, Amanda E; Calvert, Sandra L

    2011-01-01

    Digital production is a means through which African American adolescents communicate and express their experiences with peers. This study examined the content and the form of the digital productions of 24 urban, low-income African American adolescents who attended a summer academic program. The content of student digital productions focused on academic experiences and friendships. Their production styles revealed that youth used perceptually salient production features, such as rapid scene changes and loud rap music. The results suggest that when placed in a supportive, academic environment and provided with digital production resources, students who traditionally face barriers due to cultural and economic inequalities digitally express to their peers an interest in academics and positive peer relationships, and that these youth communicate their experiences through a shared production style that reflects their broader cultural experiences. PMID:21910270

  19. 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.

  20. 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.

  1. Schistosomes in South African penguins.

    PubMed

    Aldhoun, Jitka A; Horne, Elizabeth C

    2015-01-01

    During the years 2009-2012, faeces of African penguins (Spheniscus demersus L.) from South African rehabilitation centres were examined for helminths. In total, 46 out 555 samples (8.29 %), mostly belonging to adult birds, were found to contain oval schistosome eggs with a spine on one pole. Their dimensions were 153.21 ± 9.07 × 87.14 ± 8.67 μm. Selected DNA fragments (18S, 28S and ITS rDNA) were sequenced and compared to other schistosome isolates deposited in GenBank. The shape of the eggs suggests that they belong to the genus Gigantobilharzia; however, due to the insufficient stage of knowledge of the genus and limited number of species available for comparison, we were not able to assign the isolate unambiguously to this genus based on either the egg morphology or the results of molecular analysis. PMID:25339513

  2. Schistosomes in South African penguins.

    PubMed

    Aldhoun, Jitka A; Horne, Elizabeth C

    2015-01-01

    During the years 2009-2012, faeces of African penguins (Spheniscus demersus L.) from South African rehabilitation centres were examined for helminths. In total, 46 out 555 samples (8.29 %), mostly belonging to adult birds, were found to contain oval schistosome eggs with a spine on one pole. Their dimensions were 153.21 ± 9.07 × 87.14 ± 8.67 μm. Selected DNA fragments (18S, 28S and ITS rDNA) were sequenced and compared to other schistosome isolates deposited in GenBank. The shape of the eggs suggests that they belong to the genus Gigantobilharzia; however, due to the insufficient stage of knowledge of the genus and limited number of species available for comparison, we were not able to assign the isolate unambiguously to this genus based on either the egg morphology or the results of molecular analysis.

  3. Multigene Phylogenetics Reveals Temporal Diversification of Major African Malaria Vectors

    PubMed Central

    Kamali, Maryam; Marek, Paul E.; Peery, Ashley; Antonio-Nkondjio, Christophe; Ndo, Cyrille; Tu, Zhijian; Simard, Frederic; Sharakhov, Igor V.

    2014-01-01

    The major vectors of malaria in sub-Saharan Africa belong to subgenus Cellia. Yet, phylogenetic relationships and temporal diversification among African mosquito species have not been unambiguously determined. Knowledge about vector evolutionary history is crucial for correct interpretation of genetic changes identified through comparative genomics analyses. In this study, we estimated a molecular phylogeny using 49 gene sequences for the African malaria vectors An. gambiae, An. funestus, An. nili, the Asian malaria mosquito An. stephensi, and the outgroup species Culex quinquefasciatus and Aedes aegypti. To infer the phylogeny, we identified orthologous sequences uniformly distributed approximately every 5 Mb in the five chromosomal arms. The sequences were aligned and the phylogenetic trees were inferred using maximum likelihood and neighbor-joining methods. Bayesian molecular dating using a relaxed log normal model was used to infer divergence times. Trees from individual genes agreed with each other, placing An. nili as a basal clade that diversified from the studied malaria mosquito species 47.6 million years ago (mya). Other African malaria vectors originated more recently, and independently acquired traits related to vectorial capacity. The lineage leading to An. gambiae diverged 30.4 mya, while the African vector An. funestus and the Asian vector An. stephensi were the most closely related sister taxa that split 20.8 mya. These results were supported by consistently high bootstrap values in concatenated phylogenetic trees generated individually for each chromosomal arm. Genome-wide multigene phylogenetic analysis is a useful approach for discerning historic relationships among malaria vectors, providing a framework for the correct interpretation of genomic changes across species, and comprehending the evolutionary origins of this ubiquitous and deadly insect-borne disease. PMID:24705448

  4. Modification of Multiple Sclerosis Phenotypes by African Ancestry at HLA

    PubMed Central

    Cree, Bruce A. C.; Reich, David E.; Khan, Omar; De Jager, Philip L.; Nakashima, Ichiro; Takahashi, Toshiyuki; Bar-Or, Amit; Tong, Christine; Hauser, Stephen L.; Oksenberg, Jorge R.

    2015-01-01

    Background In those with multiple sclerosis (MS), African American individuals have a more severe disease course, an older age at onset, and more often have clinical manifestations restricted to the optic nerves and spinal cord (opticospinal MS) than white persons. Objective To determine whether genetic variation influences clinical MS patterns. Design Retrospective multicenter cohort study. Participants Six hundred seventy-three African American and 717 white patients with MS. Main Outcome Measures Patients with MS were geno-typed for HLA-DRB1 and HLA-DQB1 alleles. The proportion of European ancestry at HLA was estimated by genotyping single-nucleotide polymorphisms with known significant frequency differences in West African and European populations. These genotypes were correlated with the opticospinal disease phenotype, disability measures, and age at onset. Results Subjects with DRB1*15 alleles were twice as likely to have typical MS rather than opticospinal MS (P = .001). Of the subjects with opticospinal MS or a history of recurrent transverse myelitis who were seropositive for anti–aquaporin 4 antibodies (approximately 5%), none carried DRB1*15 alleles (P = .008). Independently of DRB1* 15, African ancestry at HLA correlated with disability as measured by the Multiple Sclerosis Severity Score (P < .001) andriskof cane dependency (hazard ratio, 1.36; P < .001); DRB1*15 alleles were associated with a 2.1-year earlier age at onset (P < .001). Conclusions These data indicate that the role of HLA in MS is not limited to disease susceptibility but that genes embedded in this locus also influence clinical outcomes. PMID:19204159

  5. Mental health concerns among African immigrants.

    PubMed

    Venters, Homer; Adekugbe, Olayinka; Massaquoi, Jacob; Nadeau, Cheryl; Saul, Jack; Gany, Francesca

    2011-08-01

    African immigrants represent a rapidly expanding group of immigrants in the United States. In New York City, Africans constitute the fastest growing segment of immigrants but the needs and practices of African immigrants in the U.S. remain poorly understood. A community based organization (CBO) serving African immigrants in Staten Island, NY began a health screening program in 2008 with the goal of promoting access to primary care. Over 18 months, 296 visits were recorded at African Refuge health screenings, representing a total of 87 people who averaged just over 3 visits per person. The screenings identified mental health among the top three medical problems of clients but referral to mental health services was rare. Dedicated services are required to better screen for mental health concerns and refer African immigrants to mental health care.

  6. 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.

  7. Neighborhood racial composition, racial discrimination, and depressive symptoms in African Americans.

    PubMed

    English, Devin; Lambert, Sharon F; Evans, Michele K; Zonderman, Alan B

    2014-12-01

    While evidence indicates that experienced racial discrimination is associated with increased depressive symptoms for African Americans, there is little research investigating predictors of experienced racial discrimination. This paper examines neighborhood racial composition and sociodemographic factors as antecedents to experienced racial discrimination and resultant levels of depressive symptoms among African American adults. The sample included 505 socioeconomically-diverse African American adults from Baltimore, MD. Study data were obtained via self-report and geocoding of participant addresses based on 2010 census data. Study hypotheses were tested using multiple pathways within a longitudinal Structural Equation Model. Experienced racial discrimination was positively associated with age and sex such that older individuals and males experienced increased levels of racial discrimination. In addition, the percentage of White individuals residing in a neighborhood was positively associated with levels of experienced racial discrimination for African American neighborhood residents. Experienced racial discrimination was positively associated with later depressive symptoms. Neighborhood-level contextual factors such as neighborhood racial composition and individual differences in sociodemographic characteristics appear to play an important role in the experience of racial discrimination and the etiology of depression in African American adults.

  8. Neighborhood Racial Composition, Racial Discrimination, and Depressive Symptoms in African Americans

    PubMed Central

    Lambert, Sharon F.; Evans, Michele K.; Zonderman, Alan B.

    2015-01-01

    While evidence indicates that experienced racial discrimination is associated with increased depressive symptoms for African Americans, there is little research investigating predictors of experienced racial discrimination. This paper examines neighborhood racial composition and sociodemographic factors as antecedents to experienced racial discrimination and resultant levels of depressive symptoms among African American adults. The sample included 505 socioeconomically-diverse African American adults from Baltimore, MD. Study data were obtained via self-report and geocoding of participant addresses based on 2010 census data. Study hypotheses were tested using multiple pathways within a longitudinal Structural Equation Model. Experienced racial discrimination was positively associated with age and sex such that older individuals and males experienced increased levels of racial discrimination. In addition, the percentage of White individuals residing in a neighborhood was positively associated with levels of experienced racial discrimination for African American neighborhood residents. Experienced racial discrimination was positively associated with later depressive symptoms. Neighborhood-level contextual factors such as neighborhood racial composition and individual differences in sociodemographic characteristics appear to play an important role in the experience of racial discrimination and the etiology of depression in African American adults. PMID:24969707

  9. Validation of the Wisconsin Brief Pain Questionnaire in a multilingual South African population.

    PubMed

    Mphahlele, Noko; Mitchell, Duncan; Kamerman, Peter

    2008-10-01

    Assessment of pain intensity and its effect on quality of life is important for proper management of pain, but no validated pain assessment tools that assess pain intensity and the interference pain has on daily life are available in indigenous South African languages. Therefore, the aim of this study was to validate translated versions of the Wisconsin Brief Pain Questionnaire (WBPQ) in South African HIV-positive patients. The WBPQ was translated into three indigenous South African languages, Setswana, isiZulu, and Xitsonga. We interviewed 452 ambulatory HIV-positive patients (327 urban and 125 rural patients) between the ages of 20 and 76 years old. Factor analysis to assess construct validity identified a two-factor structure (pain intensity and pain interference) for the isiZulu (n=132), Xitsonga (n=125), and Setswana (n=66) versions of the WBPQ, whereas a three-factor structure (pain intensity, mood interference, and activity interference) was identified for the English (completed by English second-language speakers, n=129) version of the WBPQ. Cronbach alphas, calculated to assess the reliability of the pain intensity and pain interference scales, were greater than 0.70 for all scales in all four versions of the WBPQ, showing internal consistency within the dimensions. These results provide evidence of validity for an easily administered questionnaire, which assesses pain intensity and pain interference, in three indigenous South African languages, and for English second-language speakers, in a population of South African HIV-positive patients.

  10. Median Approximations for Genomes Modeled as Matrices.

    PubMed

    Zanetti, Joao Paulo Pereira; Biller, Priscila; Meidanis, Joao

    2016-04-01

    The genome median problem is an important problem in phylogenetic reconstruction under rearrangement models. It can be stated as follows: Given three genomes, find a fourth that minimizes the sum of the pairwise rearrangement distances between it and the three input genomes. In this paper, we model genomes as matrices and study the matrix median problem using the rank distance. It is known that, for any metric distance, at least one of the corners is a [Formula: see text]-approximation of the median. Our results allow us to compute up to three additional matrix median candidates, all of them with approximation ratios at least as good as the best corner, when the input matrices come from genomes. We also show a class of instances where our candidates are optimal. From the application point of view, it is usually more interesting to locate medians farther from the corners, and therefore, these new candidates are potentially more useful. In addition to the approximation algorithm, we suggest a heuristic to get a genome from an arbitrary square matrix. This is useful to translate the results of our median approximation algorithm back to genomes, and it has good results in our tests. To assess the relevance of our approach in the biological context, we ran simulated evolution tests and compared our solutions to those of an exact DCJ median solver. The results show that our method is capable of producing very good candidates. PMID:27072561

  11. Approximation of virus structure by icosahedral tilings.

    PubMed

    Salthouse, D G; Indelicato, G; Cermelli, P; Keef, T; Twarock, R

    2015-07-01

    Viruses are remarkable examples of order at the nanoscale, exhibiting protein containers that in the vast majority of cases are organized with icosahedral symmetry. Janner used lattice theory to provide blueprints for the organization of material in viruses. An alternative approach is provided here in terms of icosahedral tilings, motivated by the fact that icosahedral symmetry is non-crystallographic in three dimensions. In particular, a numerical procedure is developed to approximate the capsid of icosahedral viruses by icosahedral tiles via projection of high-dimensional tiles based on the cut-and-project scheme for the construction of three-dimensional quasicrystals. The goodness of fit of our approximation is assessed using techniques related to the theory of polygonal approximation of curves. The approach is applied to a number of viral capsids and it is shown that detailed features of the capsid surface can indeed be satisfactorily described by icosahedral tilings. This work complements previous studies in which the geometry of the capsid is described by point sets generated as orbits of extensions of the icosahedral group, as such point sets are by construction related to the vertex sets of icosahedral tilings. The approximations of virus geometry derived here can serve as coarse-grained models of viral capsids as a basis for the study of virus assembly and structural transitions of viral capsids, and also provide a new perspective on the design of protein containers for nanotechnology applications. PMID:26131897

  12. Generalized string models and their semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Elizalde, E.

    1984-04-01

    We construct an extensive family of Bose string models, all of them classically equivalent to the Nambu and Eguchi models. The new models involve an arbitrary analytical function f(u), with f(0)=0, and are based on the Brink-Di Vecchia-Howe and Polyakov string action. The semiclassical approximation of the models is worked out in detail.

  13. Progressive Image Coding by Hierarchical Linear Approximation.

    ERIC Educational Resources Information Center

    Wu, Xiaolin; Fang, Yonggang

    1994-01-01

    Proposes a scheme of hierarchical piecewise linear approximation as an adaptive image pyramid. A progressive image coder comes naturally from the proposed image pyramid. The new pyramid is semantically more powerful than regular tessellation but syntactically simpler than free segmentation. This compromise between adaptability and complexity…

  14. Alternative approximation concepts for space frame synthesis

    NASA Technical Reports Server (NTRS)

    Lust, R. V.; Schmit, L. A.

    1985-01-01

    A structural synthesis methodology for the minimum mass design of 3-dimensionall frame-truss structures under multiple static loading conditions and subject to limits on displacements, rotations, stresses, local buckling, and element cross-sectional dimensions is presented. A variety of approximation concept options are employed to yield near optimum designs after no more than 10 structural analyses. Available options include: (A) formulation of the nonlinear mathematcal programming problem in either reciprocal section property (RSP) or cross-sectional dimension (CSD) space; (B) two alternative approximate problem structures in each design space; and (C) three distinct assumptions about element end-force variations. Fixed element, design element linking, and temporary constraint deletion features are also included. The solution of each approximate problem, in either its primal or dual form, is obtained using CONMIN, a feasible directions program. The frame-truss synthesis methodology is implemented in the COMPASS computer program and is used to solve a variety of problems. These problems were chosen so that, in addition to exercising the various approximation concepts options, the results could be compared with previously published work.

  15. Kravchuk functions for the finite oscillator approximation

    NASA Technical Reports Server (NTRS)

    Atakishiyev, Natig M.; Wolf, Kurt Bernardo

    1995-01-01

    Kravchuk orthogonal functions - Kravchuk polynomials multiplied by the square root of the weight function - simplify the inversion algorithm for the analysis of discrete, finite signals in harmonic oscillator components. They can be regarded as the best approximation set. As the number of sampling points increases, the Kravchuk expansion becomes the standard oscillator expansion.

  16. Approximation algorithms for planning and control

    NASA Technical Reports Server (NTRS)

    Boddy, Mark; Dean, Thomas

    1989-01-01

    A control system operating in a complex environment will encounter a variety of different situations, with varying amounts of time available to respond to critical events. Ideally, such a control system will do the best possible with the time available. In other words, its responses should approximate those that would result from having unlimited time for computation, where the degree of the approximation depends on the amount of time it actually has. There exist approximation algorithms for a wide variety of problems. Unfortunately, the solution to any reasonably complex control problem will require solving several computationally intensive problems. Algorithms for successive approximation are a subclass of the class of anytime algorithms, algorithms that return answers for any amount of computation time, where the answers improve as more time is allotted. An architecture is described for allocating computation time to a set of anytime algorithms, based on expectations regarding the value of the answers they return. The architecture described is quite general, producing optimal schedules for a set of algorithms under widely varying conditions.

  17. Parameter Choices for Approximation by Harmonic Splines

    NASA Astrophysics Data System (ADS)

    Gutting, Martin

    2016-04-01

    The approximation by harmonic trial functions allows the construction of the solution of boundary value problems in geoscience, e.g., in terms of harmonic splines. Due to their localizing properties regional modeling or the improvement of a global model in a part of the Earth's surface is possible with splines. Fast multipole methods have been developed for some cases of the occurring kernels to obtain a fast matrix-vector multiplication. The main idea of the fast multipole algorithm consists of a hierarchical decomposition of the computational domain into cubes and a kernel approximation for the more distant points. This reduces the numerical effort of the matrix-vector multiplication from quadratic to linear in reference to the number of points for a prescribed accuracy of the kernel approximation. The application of the fast multipole method to spline approximation which also allows the treatment of noisy data requires the choice of a smoothing parameter. We investigate different methods to (ideally automatically) choose this parameter with and without prior knowledge of the noise level. Thereby, the performance of these methods is considered for different types of noise in a large simulation study. Applications to gravitational field modeling are presented as well as the extension to boundary value problems where the boundary is the known surface of the Earth itself.

  18. Approximation and compression with sparse orthonormal transforms.

    PubMed

    Sezer, Osman Gokhan; Guleryuz, Onur G; Altunbasak, Yucel

    2015-08-01

    We propose a new transform design method that targets the generation of compression-optimized transforms for next-generation multimedia applications. The fundamental idea behind transform compression is to exploit regularity within signals such that redundancy is minimized subject to a fidelity cost. Multimedia signals, in particular images and video, are well known to contain a diverse set of localized structures, leading to many different types of regularity and to nonstationary signal statistics. The proposed method designs sparse orthonormal transforms (SOTs) that automatically exploit regularity over different signal structures and provides an adaptation method that determines the best representation over localized regions. Unlike earlier work that is motivated by linear approximation constructs and model-based designs that are limited to specific types of signal regularity, our work uses general nonlinear approximation ideas and a data-driven setup to significantly broaden its reach. We show that our SOT designs provide a safe and principled extension of the Karhunen-Loeve transform (KLT) by reducing to the KLT on Gaussian processes and by automatically exploiting non-Gaussian statistics to significantly improve over the KLT on more general processes. We provide an algebraic optimization framework that generates optimized designs for any desired transform structure (multiresolution, block, lapped, and so on) with significantly better n -term approximation performance. For each structure, we propose a new prototype codec and test over a database of images. Simulation results show consistent increase in compression and approximation performance compared with conventional methods. PMID:25823033

  19. Can Distributional Approximations Give Exact Answers?

    ERIC Educational Resources Information Center

    Griffiths, Martin

    2013-01-01

    Some mathematical activities and investigations for the classroom or the lecture theatre can appear rather contrived. This cannot, however, be levelled at the idea given here, since it is based on a perfectly sensible question concerning distributional approximations that was posed by an undergraduate student. Out of this simple question, and…

  20. Achievements and Problems in Diophantine Approximation Theory

    NASA Astrophysics Data System (ADS)

    Sprindzhuk, V. G.

    1980-08-01

    ContentsIntroduction I. Metrical theory of approximation on manifolds § 1. The basic problem § 2. Brief survey of results § 3. The principal conjecture II. Metrical theory of transcendental numbers § 1. Mahler's classification of numbers § 2. Metrical characterization of numbers with a given type of approximation § 3. Further problems III. Approximation of algebraic numbers by rationals § 1. Simultaneous approximations § 2. The inclusion of p-adic metrics § 3. Effective improvements of Liouville's inequality IV. Estimates of linear forms in logarithms of algebraic numbers § 1. The basic method § 2. Survey of results § 3. Estimates in the p-adic metric V. Diophantine equations § 1. Ternary exponential equations § 2. The Thue and Thue-Mahler equations § 3. Equations of hyperelliptic type § 4. Algebraic-exponential equations VI. The arithmetic structure of polynomials and the class number § 1. The greatest prime divisor of a polynomial in one variable § 2. The greatest prime divisor of a polynomial in two variables § 3. Square-free divisors of polynomials and the class number § 4. The general problem of the size of the class number Conclusion References