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Sample records for african setting methods

  1. African Swine Fever in Uganda: Qualitative Evaluation of Three Surveillance Methods with Implications for Other Resource-Poor Settings

    PubMed Central

    Chenais, Erika; Sternberg-Lewerin, Susanna; Boqvist, Sofia; Emanuelson, Ulf; Aliro, Tonny; Tejler, Emma; Cocca, Giampaolo; Masembe, Charles; Ståhl, Karl

    2015-01-01

    Animal diseases impact negatively on households and on national economies. In low-income countries, this pertains especially to socio-economic effects on household level. To control animal diseases and mitigate their impact, it is necessary to understand the epidemiology of the disease in its local context. Such understanding, gained through disease surveillance, is often lacking in resource-poor settings. Alternative surveillance methods have been developed to overcome some of the hurdles obstructing surveillance. The objective of this study was to evaluate and qualitatively compare three methods for surveillance of acute infectious diseases using African swine fever in northern Uganda as an example. Report-driven outbreak investigations, participatory rural appraisals (PRAs), and a household survey using a smartphone application were evaluated. All three methods had good disease-detecting capacity, and each of them detected many more outbreaks compared to those reported to the World Organization for Animal Health during the same time period. Apparent mortality rates were similar for the three methods although highest for the report-driven outbreak investigations, followed by the PRAs, and then the household survey. The three methods have different characteristics and the method of choice will depend on the surveillance objective. The optimal situation might be achieved by a combination of the methods: outbreak detection via smartphone-based real-time surveillance, outbreak investigation for collection of biological samples, and a PRA for a better understanding of the epidemiology of the specific outbreak. All three methods require initial investments and continuous efforts. The sustainability of the surveillance system should, therefore, be carefully evaluated before making such investments. PMID:26664978

  2. African Swine Fever in Uganda: Qualitative Evaluation of Three Surveillance Methods with Implications for Other Resource-Poor Settings.

    PubMed

    Chenais, Erika; Sternberg-Lewerin, Susanna; Boqvist, Sofia; Emanuelson, Ulf; Aliro, Tonny; Tejler, Emma; Cocca, Giampaolo; Masembe, Charles; Ståhl, Karl

    2015-01-01

    Animal diseases impact negatively on households and on national economies. In low-income countries, this pertains especially to socio-economic effects on household level. To control animal diseases and mitigate their impact, it is necessary to understand the epidemiology of the disease in its local context. Such understanding, gained through disease surveillance, is often lacking in resource-poor settings. Alternative surveillance methods have been developed to overcome some of the hurdles obstructing surveillance. The objective of this study was to evaluate and qualitatively compare three methods for surveillance of acute infectious diseases using African swine fever in northern Uganda as an example. Report-driven outbreak investigations, participatory rural appraisals (PRAs), and a household survey using a smartphone application were evaluated. All three methods had good disease-detecting capacity, and each of them detected many more outbreaks compared to those reported to the World Organization for Animal Health during the same time period. Apparent mortality rates were similar for the three methods although highest for the report-driven outbreak investigations, followed by the PRAs, and then the household survey. The three methods have different characteristics and the method of choice will depend on the surveillance objective. The optimal situation might be achieved by a combination of the methods: outbreak detection via smartphone-based real-time surveillance, outbreak investigation for collection of biological samples, and a PRA for a better understanding of the epidemiology of the specific outbreak. All three methods require initial investments and continuous efforts. The sustainability of the surveillance system should, therefore, be carefully evaluated before making such investments. PMID:26664978

  3. Implementation of Evidence-Based HIV Interventions for Young Adult African American Women in Church Settings

    PubMed Central

    Stewart, Jennifer M.

    2015-01-01

    Objective To assess the barriers and facilitators to using African American churches as sites for implementation of evidence-based HIV interventions among young African American women. Design Mixed methods cross-sectional design. Setting African American churches in Philadelphia, PA. Participants 142 African American pastors, church leaders, and young adult women ages 18 to 25. Methods Mixed methods convergent parallel design. Results The majority of young adult women reported engaging in high-risk HIV-related behaviors. Although church leaders reported willingness to implement HIV risk-reduction interventions, they were unsure of how to initiate this process. Key facilitators to the implementation of evidence-based interventions included the perception of the leadership and church members that HIV interventions were needed and that the church was a promising venue for them. A primary barrier to implementation in this setting is the perception that discussions of sexuality should be private. Conclusion Implementation of evidence-based HIV interventions for young adult African American women in church settings is feasible and needed. Building a level of comfort in discussing matters of sexuality and adapting existing evidence-based interventions to meet the needs of young women in church settings is a viable approach for successful implementation. PMID:25139612

  4. Comparing sociocultural features of cholera in three endemic African settings

    PubMed Central

    2013-01-01

    Background Cholera mainly affects developing countries where safe water supply and sanitation infrastructure are often rudimentary. Sub-Saharan Africa is a cholera hotspot. Effective cholera control requires not only a professional assessment, but also consideration of community-based priorities. The present work compares local sociocultural features of endemic cholera in urban and rural sites from three field studies in southeastern Democratic Republic of Congo (SE-DRC), western Kenya and Zanzibar. Methods A vignette-based semistructured interview was used in 2008 in Zanzibar to study sociocultural features of cholera-related illness among 356 men and women from urban and rural communities. Similar cross-sectional surveys were performed in western Kenya (n = 379) and in SE-DRC (n = 360) in 2010. Systematic comparison across all settings considered the following domains: illness identification; perceived seriousness, potential fatality and past household episodes; illness-related experience; meaning; knowledge of prevention; help-seeking behavior; and perceived vulnerability. Results Cholera is well known in all three settings and is understood to have a significant impact on people’s lives. Its social impact was mainly characterized by financial concerns. Problems with unsafe water, sanitation and dirty environments were the most common perceived causes across settings; nonetheless, non-biomedical explanations were widespread in rural areas of SE-DRC and Zanzibar. Safe food and water and vaccines were prioritized for prevention in SE-DRC. Safe water was prioritized in western Kenya along with sanitation and health education. The latter two were also prioritized in Zanzibar. Use of oral rehydration solutions and rehydration was a top priority everywhere; healthcare facilities were universally reported as a primary source of help. Respondents in SE-DRC and Zanzibar reported cholera as affecting almost everybody without differentiating much for gender, age

  5. Measuring African-American parents' cultural mistrust while in a healthcare setting: a pilot study.

    PubMed Central

    Moseley, Kathryn L.; Freed, Gary L.; Bullard, Charrell M.; Goold, Susan D.

    2007-01-01

    BACKGROUND: African Americans' mistrust of healthcare is often cited as a cause of racial disparities in health and has been linked to cultural mistrust. African-American parents' level of cultural mistrust while in a general healthcare setting has not been previously measured. OBJECTIVE: To determine the performance, participant acceptance, feasibility of administration and demographic associations of a measure of cultural mistrust, the Cultural Mistrust Inventory (CMI), in African-American parents seeking healthcare. METHODS: A cross-sectional sample of 69 self-identified African-American parents of minor children recruited in a university-affiliated, urban pediatric/family practice outpatient clinic completed an anonymous, self-administered questionnaire containing demographic items and the CMI. RESULTS: The response rate was 91% (n=63), and 49 (78%) -- answered all questions. Measured mistrust did not vary with gender, insurance or education. The CMI's internal consistency was similar to previously published studies of the instrument (alpha=0.92). Parents indicating discomfort with the CMI's questions reported significantly less mistrust than parents who did not indicate discomfort (p=0.01). CONCLUSIONS: The CMI is feasible to administer in a clinic setting and demonstrates good internal consistency. It can be a useful tool to assess the effect of cultural mistrust on the healthcare decisions African-American parents make for their children. However, when measuring cultural mistrust in a healthcare setting, respondents' comfort with the survey questions should be assessed. PMID:17304964

  6. Fighting through Resistance: Challenges Faced by African American Women Principals in Predominately White School Settings

    ERIC Educational Resources Information Center

    Jackson, Alicia D.

    2013-01-01

    African American women represented a growing proportion within the field of education in attaining leadership roles as school principals. As the numbers continued to rise slowly, African American women principals found themselves leading in diverse or even predominately White school settings. Leading in such settings encouraged African American…

  7. The Mapmark Standard Setting Method

    ERIC Educational Resources Information Center

    Schulz, E. Matthew; Mitzel, Howard C.

    2005-01-01

    A new standard setting method, Mapmark, was recently developed by ACT Inc. in the course of a contract with the National Assessment Governing Board (NAGB) to set achievement levels for the 2005 National Assessment of Educational Progress (NAEP) in Grade 12 mathematics. Mapmark includes elements of the bookmark method (Lewis, Mitzel, & Green, 1996;…

  8. African Dance Aesthetics in a K-12 Dance Setting: From History to Social Justice

    ERIC Educational Resources Information Center

    Ward, Sheila A.

    2013-01-01

    This article invites the reader to gain a deeper understanding of the aesthetics of African-based dance through the elements of tradition, transformation, and social justice. A discussion of the aesthetics of African dances within Africa and throughout the African diaspora opens the doors to present these dances in a K-12 setting, to explore a…

  9. An adaptive level set method

    SciTech Connect

    Milne, R.B.

    1995-12-01

    This thesis describes a new method for the numerical solution of partial differential equations of the parabolic type on an adaptively refined mesh in two or more spatial dimensions. The method is motivated and developed in the context of the level set formulation for the curvature dependent propagation of surfaces in three dimensions. In that setting, it realizes the multiple advantages of decreased computational effort, localized accuracy enhancement, and compatibility with problems containing a range of length scales.

  10. A multi-level approach for promoting HIV testing within African American church settings.

    PubMed

    Stewart, Jennifer M

    2015-02-01

    The African American church is a community-based organization that is integral to the lives, beliefs, and behaviors of the African American community. Engaging this vital institution as a primary setting for HIV testing and referral would significantly impact the epidemic. The disproportionately high HIV incidence rate among African Americans dictates the national priority for promotion of early and routine HIV testing, and suggests engaging community-based organizations in this endeavor. However, few multilevel HIV testing frameworks have been developed, tested, and evaluated within the African American church. This article proposes one such framework for promoting HIV testing and referral within African American churches. A qualitative study was employed to examine the perceptions, beliefs, knowledge, and behaviors related to understanding involvement in church-based HIV testing. A total of four focus groups with church leaders and four in-depth interviews with pastors, were conducted between November 2012 and June 2013 to identify the constructs most important to supporting Philadelphia churches' involvement in HIV testing, referral, and linkage to care. The data generated from this study were analyzed using a grounded theory approach and used to develop and refine a multilevel framework for identifying factors impacting church-based HIV testing and referral and to ultimately support capacity building among African American churches to promote HIV testing and linkage to care.

  11. Implementing Conjoint Behavioral Consultation for African American Children from a Low-SES, Urban Setting

    ERIC Educational Resources Information Center

    Ohmstede, Tammi J.; Yetter, Georgette

    2015-01-01

    This study investigated the effectiveness of conjoint behavioral consultation (CBC) for addressing externalizing behavior concerns in African American children at home and school in a low-socioeconomic status (SES), urban setting. A small-n, multiple-baseline design was employed across participants. Three of the six caregivers were unable to…

  12. Towards setting environmental water temperature guidelines: a South African example.

    PubMed

    Rivers-Moore, Nicholas A; Dallas, Helen F; Morris, Craig

    2013-10-15

    Water temperature is a primary factor affecting the number and kinds of species in a stream. A key step towards including water temperatures in environmental flow assessments is to develop metrics which describe natural variability in a river's thermal regime. This is best achieved using time series analyses, where metrics are defined based either on time series disaggregation, or shapes of regimes defined using agglomerative techniques. The aim of this paper was to refine approaches in setting environmental water temperature guidelines for inclusion in defining environmental flows assessments. Annual water temperature series from 82 sites sampled across 48 rivers (mainstems and tributaries) in ten catchments in the southern Cape region of South Africa were described using 39 metrics based on the magnitude, frequency, duration and timing of thermal events. Sites were classified into thermal groups using their similarity in multivariate temperature regime and variation amongst groups along important temperature gradients examined. Deviation from a natural range of variability using a thermal confidence envelope is a suitable approach for broad evaluation of thermal guidelines. The approach presented can be applied at multiple levels of complexity to assess which elements of a thermal time series fall outside of reference conditions. Further steps in this approach are to link thermal patterns to biotic metrics, and gain a clearer understanding of interactions between flows, temperatures and biota, particularly below impoundments. Research on improving approaches in defining thermal regions is recommended.

  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. A language screening protocol for use with young African American children in urban settings.

    PubMed

    Washington, Julie A; Craig, Holly K

    2004-11-01

    Language screenings represent an important tool for early identification of language impairments in young children between 3 and 5 years of age. This investigation examined the utility of a well-established set of assessment measures for screening young African American children. One hundred and ninety-six children participated in the screening. Based upon the outcomes of the screening, 25 children who failed and a random sample of 56 children who passed were administered a larger language and cognitive assessment battery. Sensitivity and specificity of the screening were determined to be high. The number of different words, the Kaufman Nonverbal Scale, and nonword repetition accounted for a significant amount of the variance in performance. The screening is brief, valid, and culturally fair for use with preschool- and kindergarten-aged African American children living in urban settings. PMID:15719899

  16. Exploring Leadership through Spiritual Practices and African Moral Virtues: Portraits of African American Women Principals in Urban Settings

    ERIC Educational Resources Information Center

    Smith, Sharon Irene

    2009-01-01

    The purpose of this qualitative study was to explore the influences of spirituality on decisions made by African American women principals at the elementary school level in schools where children of color and poverty exist in significant numbers and to gain an understanding of how African moral virtues were evidenced in the day to day professional…

  17. Level Set Method for Positron Emission Tomography

    PubMed Central

    Chan, Tony F.; Li, Hongwei; Lysaker, Marius; Tai, Xue-Cheng

    2007-01-01

    In positron emission tomography (PET), a radioactive compound is injected into the body to promote a tissue-dependent emission rate. Expectation maximization (EM) reconstruction algorithms are iterative techniques which estimate the concentration coefficients that provide the best fitted solution, for example, a maximum likelihood estimate. In this paper, we combine the EM algorithm with a level set approach. The level set method is used to capture the coarse scale information and the discontinuities of the concentration coefficients. An intrinsic advantage of the level set formulation is that anatomical information can be efficiently incorporated and used in an easy and natural way. We utilize a multiple level set formulation to represent the geometry of the objects in the scene. The proposed algorithm can be applied to any PET configuration, without major modifications. PMID:18354724

  18. Novelty detection using level set methods.

    PubMed

    Ding, Xuemei; Li, Yuhua; Belatreche, Ammar; Maguire, Liam P

    2015-03-01

    This paper presents a level set boundary description (LSBD) approach for novelty detection that treats the nonlinear boundary directly in the input space. The proposed approach consists of level set function (LSF) construction, boundary evolution, and termination of the training process. It employs kernel density estimation to construct the LSF of the initial boundary for the training data set. Then, a sign of the LSF-based algorithm is proposed to evolve the boundary and make it fit more tightly in the data distribution. The training process terminates when an expected fraction of rejected normal data is reached. The evolution process utilizes the signs of the LSF values at all training data points to decide whether to expand or shrink the boundary. Extensive experiments are conducted on benchmark data sets to evaluate the proposed LSBD method and compare it against four representative novelty detection methods. The experimental results demonstrate that the novelty detector modeled with the proposed LSBD can effectively detect anomalies. PMID:25720011

  19. The Objective Borderline Method: A Probabilistic Method for Standard Setting

    ERIC Educational Resources Information Center

    Shulruf, Boaz; Poole, Phillippa; Jones, Philip; Wilkinson, Tim

    2015-01-01

    A new probability-based standard setting technique, the Objective Borderline Method (OBM), was introduced recently. This was based on a mathematical model of how test scores relate to student ability. The present study refined the model and tested it using 2500 simulated data-sets. The OBM was feasible to use. On average, the OBM performed well…

  20. Who We Are: (In)visible African American Women Setting Traditions of Excellence and Paving Paths for Transformation

    ERIC Educational Resources Information Center

    O'Bryant, Camille

    2015-01-01

    The purpose of this lecture is to provide the voice and visibility of African American women who have upheld the tradition of excellence set by Amy Morris Homans in the development of physical education in higher education for women and set pathways to transition our field to be more inclusive and diverse and have served as transformative leaders…

  1. Pathways of care-seeking during fatal infant illnesses in under-resourced South African settings

    PubMed Central

    Sharkey, Alyssa B; Chopra, Mickey; Jackson, Debra; Winch, Peter J; Minkovitz, Cynthia S

    2011-01-01

    Summary The purpose of this study was to examine care-seeking during fatal infant illnesses in under-resourced South African settings to inform potential strategies for reducing infant mortality. We interviewed 22 caregivers of deceased infants in a rural community and 28 in an urban township. We also interviewed seven local leaders and 12 health providers to ascertain opinions about factors contributing to infant death. Despite the availability of free public health services in these settings, many caregivers utilised multiple sources of care including allopathic, indigenous and home treatments. Urban caregivers reported up to eight points of care while rural caregivers reported up to four points of care. The specific pathways taken and combinations of care varied, but many caregivers used other types of care shortly after presenting at public services, indicating dissatisfaction with the care they received. Many infants died despite caregivers’ considerable efforts, pointing to critical deficiencies in the system of care serving these families. Initiatives that aim to improve assessment, management and referral practices by both allopathic and traditional providers (for example, through training and improved collaboration), and caregiver recognition of infant danger signs may reduce the high rate of infant death in these settings. PMID:22136954

  2. Evaluation of a health setting-based stigma intervention in five African countries.

    PubMed

    Uys, Leana; Chirwa, Maureen; Kohi, Thecla; Greeff, Minrie; Naidoo, Joanne; Makoae, Lucia; Dlamini, Priscilla; Durrheim, Kevin; Cuca, Yvette; Holzemer, William L

    2009-12-01

    The study aim is to explore the results of an HIV stigma intervention in five African health care settings. A case study approach was used. The intervention consisted of bringing together a team of approximately 10 nurses and 10 people living with HIV or AIDS (PLHA) in each setting and facilitating a process in which they planned and implemented a stigma reduction intervention, involving both information giving and empowerment. Nurses (n = 134) completed a demographic questionnaire, the HIV/AIDS Stigma Instrument-Nurses (HASI-N), a self-efficacy scale, and a self-esteem scale, both before and after the intervention, and the team completed a similar set of instruments before and after the intervention, with the PLHA completing the HIV/AIDS Stigma Instrument for PLHA (HASI-P). The intervention as implemented in all five countries was inclusive, action-oriented, and well received. It led to understanding and mutual support between nurses and PLHA and created some momentum in all the settings for continued activity. PLHA involved in the intervention teams reported less stigma and increased self-esteem. Nurses in the intervention teams and those in the settings reported no reduction in stigma or increases in self- esteem and self-efficacy, but their HIV testing behavior increased significantly. This pilot study indicates that the stigma experience of PLHA can be decreased, but that the stigma experiences of nurses are less easy to change. Further evaluation research with control groups and larger samples and measuring change over longer periods of time is indicated. PMID:20025515

  3. Evaluation of a Health Setting-Based Stigma Intervention in Five African Countries

    PubMed Central

    Uys, Leana; Chirwa, Maureen; Kohi, Thecla; Greeff, Minrie; Makoae, Lucia; Dlamini, Priscilla; Durrheim, Kevin; Cuca, Yvette; Holzemer, William L.

    2009-01-01

    Abstract The study aim is to explore the results of an HIV stigma intervention in five African health care settings. A case study approach was used. The intervention consisted of bringing together a team of approximately 10 nurses and 10 people living with HIV or AIDS (PLHA) in each setting and facilitating a process in which they planned and implemented a stigma reduction intervention, involving both information giving and empowerment. Nurses (n = 134) completed a demographic questionnaire, the HIV/AIDS Stigma Instrument-Nurses (HASI-N), a self-efficacy scale, and a self-esteem scale, both before and after the intervention, and the team completed a similar set of instruments before and after the intervention, with the PLHA completing the HIV/AIDS Stigma Instrument for PLHA (HASI-P). The intervention as implemented in all five countries was inclusive, action-oriented, and well received. It led to understanding and mutual support between nurses and PLHA and created some momentum in all the settings for continued activity. PLHA involved in the intervention teams reported less stigma and increased self-esteem. Nurses in the intervention teams and those in the settings reported no reduction in stigma or increases in self- esteem and self-efficacy, but their HIV testing behavior increased significantly. This pilot study indicates that the stigma experience of PLHA can be decreased, but that the stigma experiences of nurses are less easy to change. Further evaluation research with control groups and larger samples and measuring change over longer periods of time is indicated. PMID:20025515

  4. Etch Profile Simulation Using Level Set Methods

    NASA Technical Reports Server (NTRS)

    Hwang, Helen H.; Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

    1997-01-01

    Etching and deposition of materials are critical steps in semiconductor processing for device manufacturing. Both etching and deposition may have isotropic and anisotropic components, due to directional sputtering and redeposition of materials, for example. Previous attempts at modeling profile evolution have used so-called "string theory" to simulate the moving solid-gas interface between the semiconductor and the plasma. One complication of this method is that extensive de-looping schemes are required at the profile corners. We will present a 2D profile evolution simulation using level set theory to model the surface. (1) By embedding the location of the interface in a field variable, the need for de-looping schemes is eliminated and profile corners are more accurately modeled. This level set profile evolution model will calculate both isotropic and anisotropic etch and deposition rates of a substrate in low pressure (10s mTorr) plasmas, considering the incident ion energy angular distribution functions and neutral fluxes. We will present etching profiles of Si substrates in Ar/Cl2 discharges for various incident ion energies and trench geometries.

  5. Influences on Healthcare-seeking during Final Illnesses of Infants in Under-resourced South African Settings

    PubMed Central

    Chopra, Mickey; Jackson, Debra; Winch, Peter J.; Minkovitz, Cynthia S

    2011-01-01

    To examine how health caregivers in under-resourced South African settings select from among the healthcare alternatives available to them during the final illness of their infants, qualitative interviews were conducted with 39 caregivers of deceased infants in a rural community and an urban township. Nineteen local health providers and community leaders were also interviewed to ascertain opinions about local healthcare and other factors impacting healthcare-seeking choices. The framework analysis method guided qualitative analysis of data. Limited autonomy of caregivers in decision-making, lack of awareness of infant danger-signs, and identification of an externalizing cause of illness were important influences on healthcare-seeking during illnesses of infants in these settings. Health system factors relating to the performance of health workers and the accessibility and availability of services also influenced healthcare-seeking decisions. Although South African public-health services are free, the findings showed that poor families faced other financial constraints that impacted their access to healthcare. Often there was not one factor but a combination of factors occurring either concurrently or sequentially that determined whether, when, and from where outside healthcare was sought during final illnesses of infants. In addition to reducing health system barriers to healthcare, initiatives to improve timely and appropriate healthcare-seeking for sick infants must take into consideration ways to mitigate contextual problems, such as limited autonomy of caregivers in decision-making, and reconcile local explanatory models of childhood illnesses that may not encourage healthcare-seeking at allopathic services. PMID:21957677

  6. Bushmeat genetics: setting up a reference framework for the DNA typing of African forest bushmeat.

    PubMed

    Gaubert, Philippe; Njiokou, Flobert; Olayemi, Ayodeji; Pagani, Paolo; Dufour, Sylvain; Danquah, Emmanuel; Nutsuakor, Mac Elikem K; Ngua, Gabriel; Missoup, Alain-Didier; Tedesco, Pablo A; Dernat, Rémy; Antunes, Agostinho

    2015-05-01

    The bushmeat trade in tropical Africa represents illegal, unsustainable off-takes of millions of tons of wild game - mostly mammals - per year. We sequenced four mitochondrial gene fragments (cyt b, COI, 12S, 16S) in >300 bushmeat items representing nine mammalian orders and 59 morphological species from five western and central African countries (Guinea, Ghana, Nigeria, Cameroon and Equatorial Guinea). Our objectives were to assess the efficiency of cross-species PCR amplification and to evaluate the usefulness of our multilocus approach for reliable bushmeat species identification. We provide a straightforward amplification protocol using a single 'universal' primer pair per gene that generally yielded >90% PCR success rates across orders and was robust to different types of meat preprocessing and DNA extraction protocols. For taxonomic identification, we set up a decision pipeline combining similarity- and tree-based approaches with an assessment of taxonomic expertise and coverage of the GENBANK database. Our multilocus approach permitted us to: (i) adjust for existing taxonomic gaps in GENBANK databases, (ii) assign to the species level 67% of the morphological species hypotheses and (iii) successfully identify samples with uncertain taxonomic attribution (preprocessed carcasses and cryptic lineages). High levels of genetic polymorphism across genes and taxa, together with the excellent resolution observed among species-level clusters (neighbour-joining trees and Klee diagrams) advocate the usefulness of our markers for bushmeat DNA typing. We formalize our DNA typing decision pipeline through an expert-curated query database - DNA BUSHMEAT - that shall permit the automated identification of African forest bushmeat items.

  7. Challenges to HIV prevention in psychiatric settings: Perceptions of South African mental health care providers

    PubMed Central

    Collins, Pamela Y.

    2009-01-01

    Mental health services in South Africa increasingly feel the brunt of the AIDS epidemic. Despite the high prevalence of infection in the psychiatric setting, HIV risk reduction interventions targeting South Africans with psychiatric illness remain few and far between. The attitudes of mental health care providers about sexual relations and HIV among people with mental illness continue to influence the extent to which these issues are addressed in care settings. This study examines these attitudes through the use of a semi-structured interview administered to 46 mental health care providers in four provinces of South Africa. I found that personal, contextual and political factors in the clinic and the hospital create barriers to integrating prevention activities. In particular, providers face at least three challenges to intervening in the epidemic among their patients: their own views of psychiatric illness, the transitions occurring in the mental health care system, and shifting social attitudes toward sexuality. Barriers operate at the individual level, the institutional level, and the societal level. At the individual level providers’ perceptions of psychiatric symptoms shape their outlook on intervention with psychiatric patients. At the institutional level disruptive transitions in service delivery relegate HIV services to lesser importance. At the societal level, personal beliefs about sexuality and mental illness have remained slow to change despite major political changes. Minimizing barriers to implementing HIV prevention services requires institutional and health care policies that ensure adequate resources for treating people with mental illness and for staff development and support. PMID:16647793

  8. Standard Setting Lessons Learned in the South African Context: Implications for International Implementation

    ERIC Educational Resources Information Center

    Pitoniak, Mary J.; Yeld, Nan

    2013-01-01

    Criterion-referenced assessments have become more common around the world, with performance standards being set to differentiate different levels of student performance. However, use of standard setting methods developed in the United States may be complicated by factors related to the political and educational contexts within another country. In…

  9. Accounting for the Attrition of African American Males in an Academic Support Setting

    ERIC Educational Resources Information Center

    Lancia, Ronald R.

    2013-01-01

    This dissertation addresses a continuing crisis in our nation's education system. Historically African American students have underperformed academically. This achievement gap is particularly pronounced for African American males. AVID (Advancement Via Individual Determination), an academic support program for underachieving students, most…

  10. Methods for growing and titrating African swine fever virus: field and laboratory samples.

    PubMed

    Carrascosa, Angel L; Bustos, M Jose; de Leon, Patricia

    2011-12-01

    Growing African swine fever virus (ASFV) isolates obtained mainly from the field, but also engineered in the laboratory, is a critical step for diagnosis, titration, or virus infection studies. This unit describes a set of methods and protocols to produce and titrate any ASFV strain in cell cultures. The procedures include (1) basic techniques to prepare virus-sensitive target cells; (2) strategies for growth, concentration, and purification of virus stocks; and (3) the semi-quantitative (end dilution) and quantitative (plaque) assays for the determination of viral titers, and the use of different ASFV-sensitive cells as targets for virus production and titration.

  11. Evaluation of Giant African Pouched Rats for Detection of Pulmonary Tuberculosis in Patients from a High-Endemic Setting

    PubMed Central

    Reither, Klaus; Jugheli, Levan; Glass, Tracy R.; Sasamalo, Mohamed; Mhimbira, Francis A.; Weetjens, Bart J.; Cox, Christophe; Edwards, Timothy L.; Mulder, Christiaan; Beyene, Negussie W.; Mahoney, Amanda

    2015-01-01

    Background This study established evidence about the diagnostic performance of trained giant African pouched rats for detecting Mycobacterium tuberculosis in sputum of well-characterised patients with presumptive tuberculosis (TB) in a high-burden setting. Methods The TB detection rats were evaluated using sputum samples of patients with presumptive TB enrolled in two prospective cohort studies in Bagamoyo, Tanzania. The patients were characterised by sputum smear microscopy and culture, including subsequent antigen or molecular confirmation of Mycobacterium tuberculosis, and by clinical data at enrolment and for at least 5-months of follow-up to determine the reference standard. Seven trained giant African pouched rats were used for the detection of TB in the sputum samples after shipment to the APOPO project in Morogoro, Tanzania. Results Of 469 eligible patients, 109 (23.2%) were culture-positive for Mycobacterium tuberculosis and 128 (27.3%) were non-TB controls with sustained recovery after 5 months without anti-TB treatment. The HIV prevalence was 46%. The area under the receiver operating characteristic curve of the seven rats for the detection of culture-positive pulmonary tuberculosis was 0.72 (95% CI 0.66–0.78). An optimal threshold could be defined at ≥2 indications by rats in either sample with a corresponding sensitivity of 56.9% (95% CI 47.0–66.3), specificity of 80.5% (95% CI 72.5–86.9), positive and negative predictive value of 71.3% (95% CI 60.6–80.5) and 68.7% (95% CI 60.6–76.0), and an accuracy for TB diagnosis of 69.6%. The diagnostic performance was negatively influenced by low burden of bacilli, and independent of the HIV status. Conclusion Giant African pouched rats have potential for detection of tuberculosis in sputum samples. However, the diagnostic performance characteristics of TB detection rats do not currently meet the requirements for high-priority, rapid sputum-based TB diagnostics as defined by the World Health

  12. Alternative Methods for Measuring Obesity in African American Women

    PubMed Central

    Clark, Ashley E.; Taylor, Jacquelyn Y.; Wu, Chun Yi; Smith, Jennifer A.

    2013-01-01

    The use of body mass index (BMI) may not be the most appropriate measurement tool in determining obesity in diverse populations. We studied a convenience sample of 108 African American (AA) women to determine the best method for measuring obesity in this at-risk population. The purpose of this study was to determine if percent body fat (PBF) and percent body water (PBW) could be used as alternatives to BMI in predicting obesity and risk for hypertension (HTN) among AA women. After accounting for age, BMI, and the use of anti-hypertensive medication, PBF (p = 0.0125) and PBW (p = 0.0297) were significantly associated with systolic blood pressure, while BMI was not. Likewise, PBF (p = 0.0316) was significantly associated with diastolic blood pressure, while PBW and BMI were not. Thus, health care practitioners should consider alternative anthropometric measurements such as PBF when assessing obesity in AA women. PMID:23483836

  13. Biopsychosocial Correlates of Binge Eating Disorder in Caucasian and African American Women with Obesity in Primary Care Settings.

    PubMed

    Udo, Tomoko; White, Marney A; Lydecker, Janet L; Barnes, Rachel D; Genao, Inginia; Garcia, Rina; Masheb, Robin M; Grilo, Carlos M

    2016-05-01

    This study examined racial differences in eating-disorder psychopathology, eating/weight-related histories, and biopsychosocial correlates in women (n = 53 Caucasian and n = 56 African American) with comorbid binge eating disorder (BED) and obesity seeking treatment in primary care settings. Caucasians reported significantly earlier onset of binge eating, dieting, and overweight, and greater number of times dieting than African American. The rate of metabolic syndrome did not differ by race. Caucasians had significantly elevated triglycerides whereas African Americans showed poorer glycaemic control (higher glycated haemoglobin A1c [HbA1c]), and significantly higher diastolic blood pressure. There were no significant racial differences in features of eating disorders, depressive symptoms, or mental and physical health functioning. The clinical presentation of eating-disorder psychopathology and associated psychosocial functioning differed little by race among obese women with BED seeking treatment in primary care settings. Clinicians should assess for and institute appropriate interventions for comorbid BED and obesity in both African American and Caucasian patients.

  14. Biopsychosocial Correlates of Binge Eating Disorder in Caucasian and African American Women with Obesity in Primary Care Settings.

    PubMed

    Udo, Tomoko; White, Marney A; Lydecker, Janet L; Barnes, Rachel D; Genao, Inginia; Garcia, Rina; Masheb, Robin M; Grilo, Carlos M

    2016-05-01

    This study examined racial differences in eating-disorder psychopathology, eating/weight-related histories, and biopsychosocial correlates in women (n = 53 Caucasian and n = 56 African American) with comorbid binge eating disorder (BED) and obesity seeking treatment in primary care settings. Caucasians reported significantly earlier onset of binge eating, dieting, and overweight, and greater number of times dieting than African American. The rate of metabolic syndrome did not differ by race. Caucasians had significantly elevated triglycerides whereas African Americans showed poorer glycaemic control (higher glycated haemoglobin A1c [HbA1c]), and significantly higher diastolic blood pressure. There were no significant racial differences in features of eating disorders, depressive symptoms, or mental and physical health functioning. The clinical presentation of eating-disorder psychopathology and associated psychosocial functioning differed little by race among obese women with BED seeking treatment in primary care settings. Clinicians should assess for and institute appropriate interventions for comorbid BED and obesity in both African American and Caucasian patients. PMID:26640009

  15. African Traditional Education: A Method of Dissseminating Cultural Values.

    ERIC Educational Resources Information Center

    Boateng, Felix

    1983-01-01

    Describes how the philosophical foundations of traditional African education, including oral literature, secret societies and other religious practices, served as a vehicle for intergenerational communication. Warns educational planners in contemporary Africa that a rejection of African heritage will create confusion, loss of identity, and a break…

  16. Effects on Sexual Risk Behavior and STD Rate of Brief HIV/STD Prevention Interventions for African American Women in Primary Care Settings

    PubMed Central

    Jemmott, Loretta Sweet; Jemmott, John B.; O’Leary, Ann

    2007-01-01

    Objectives. We tested the efficacy of brief HIV/sexually transmitted disease (STD) risk-reduction interventions for African American women in primary care settings. Methods. In a randomized controlled trial, 564 African American women recruited at a Newark, NJ, inner-city women’s health clinic were assigned to a 20-minute one-on-one HIV/STD behavioral skill-building intervention, 200-minute group HIV/STD behavioral skill-building intervention, 20-minute one-on-one HIV/STD information intervention, 200-minute group HIV/STD information intervention, or 200-minute health intervention control group. Primary outcomes were self-reported sexual behaviors in the previous 3 months; secondary outcome was STD incidence. Results. At 12-month follow-up, participants in the skill-building interventions reported less unprotected sexual intercourse than did participants in the information interventions (Cohen’s d [d]=0.23, P=.02), reported a greater proportion of protected sexual intercourse than did information intervention participants (d=0.21, P=.05) and control participants (d=0.24, P=.03), and were less likely to test positive for an STD than were control participants (d=0.20, P=.03). Conclusions. This study suggests that brief single-session, one-on-one or group skill-building interventions may reduce HIV/STD risk behaviors and STD morbidity among inner-city African American women in primary care settings. PMID:17463391

  17. A review of hypoglycaemia in a South African family practice setting

    PubMed Central

    Ross, Andrew J.; Campbell, Laura

    2016-01-01

    Background The prevalence and incidence of diabetes in South Africa are high and are expected to increase. Mortality and morbidity may be related to hypoglycaemia, and there is limited information on hypoglycaemia from private practice sites. The aim of this study was to assess patients’ education about, knowledge of and response to hypoglycaemia. Methods The study site was a general practice, and participants were all patients with diabetes who presented to the practice over a 1-month period. Data were collected using a closed-ended questionnaire and analysed descriptively. Findings Most respondents were South Africans of Indian origin and were diagnosed with diabetes at a relatively young age. Despite attending a private practice, most had low incomes and low schooling levels. Just under half reported having experienced hypoglycaemia, and there was a strong association between hypoglycaemia and insulin use. Many reported never having received any education around hypoglycaemia. Discussion The study highlights the need for early screening for diabetes in this vulnerable population. Hypoglycaemic education should consider low schooling levels even in a private general practice, and further study is required on the quality and frequency of education provided in general practice. PMID:27380790

  18. Harvest Health: Translation of the Chronic Disease Self-Management Program for Older African Americans in a Senior Setting

    ERIC Educational Resources Information Center

    Gitlin, Laura N.; Chernett, Nancy L.; Harris, Lynn Fields; Palmer, Delores; Hopkins, Paul; Dennis, Marie P.

    2008-01-01

    Purpose: We describe the translation of K. R. Lorig and colleagues' Chronic Disease Self-Management Program (CDSMP) for delivery in a senior center and evaluate pre-post benefits for African American participants. Design and Methods: Modifications to the CDSMP included a name change; an additional introductory session; and course augmentations…

  19. Does Geographic Setting Alter the Roles of Academically Supportive Factors? African American Adolescents' Friendships, Math Self-Concept, and Math Performance

    ERIC Educational Resources Information Center

    Jones, Martin H.; Irvin, Matthew J.; Kibe, Grace W.

    2012-01-01

    The study is one of few to examine how living in rural, suburban, or urban settings may alter factors supporting African Americans adolescents' math performance. The study examines the relationship of math self-concept and perceptions of friends' academic behaviors to African American students' math performance. Participants (N = 1,049) are…

  20. Speaking up for African American English: Equity and Inclusion in Early Childhood Settings

    ERIC Educational Resources Information Center

    Beneke, Margaret; Cheatham, Gregory A.

    2015-01-01

    A large percentage of young children entering preschool are English speakers who speak a language variety that often differs from the English dialect expected by educators within early childhood programs. While African American English (AAE) is one of the most widely recognized English dialects in the United States, the use of AAE in schools and…

  1. The Relationship between Creativity and Mental Disorder in an African Setting***

    PubMed Central

    Olugbile, O.; Zachariah, M.P.

    2011-01-01

    Background: There has for some time now been recognition that there was a relationship between exceptional creative talent and mental disorder. The works of Andreasen (2008) and others in this area have been very significant. However, most of the research has been carried out in USA and Europe. Very little has come out of Africa on the subject. Aim: To survey the beliefs of different groups within an African society, concerning the possibility of a relationship between creative talent and mental disorder. To assess creativity within a community of people with a formal diagnosis of mental disorder. Materials and Methods: Some of the mythology of the Yoruba was examined for content, concerning the behaviour of certain notable individuals and the existence of psychopathology based on modern-day criteria. The beliefs of members of the general public and mental health professionals concerning the existence of a relationship between creative talent and psychopathology were surveyed using a questionnaire designed for the project. A sample of patients with formal diagnoses of affective disorder or schizophrenia drawn from two units, the Lagos State University Teaching Hospital and the Federal Neuropsychiatric Hospital Yaba, were assessed for ‘Creativity.’ Results Although there are notable ‘eccentric’ figures in local mythology, the overwhelming majority of the people surveyed do not believe there is any relationship between creativity and mental illness. They however believe that engaging in creative activities helps the mentally ill to recover from illness. The mental health professionals, who were clinical psychologists and psychiatrists, had a significant minority who believed that a relationship does exist, and they also strongly assert that creative activity has a therapeutic effect for the mentally ill. A survey of in-patients diagnosed with schizophrenia and affective disorder failed to show a significant difference in the creativity of the two populations

  2. Revealing the Micro-scale Signature of Endemic Zoonotic Disease Transmission in an African Urban Setting.

    PubMed

    Bourhy, Hervé; Nakouné, Emmanuel; Hall, Matthew; Nouvellet, Pierre; Lepelletier, Anthony; Talbi, Chiraz; Watier, Laurence; Holmes, Edward C; Cauchemez, Simon; Lemey, Philippe; Donnelly, Christl A; Rambaut, Andrew

    2016-04-01

    The development of novel approaches that combine epidemiological and genomic data provides new opportunities to reveal the spatiotemporal dynamics of infectious diseases and determine the processes responsible for their spread and maintenance. Taking advantage of detailed epidemiological time series and viral sequence data from more than 20 years reported by the National Reference Centre for Rabies of Bangui, the capital city of Central African Republic, we used a combination of mathematical modeling and phylogenetic analysis to determine the spatiotemporal dynamics of rabies in domestic dogs as well as the frequency of extinction and introduction events in an African city. We show that although dog rabies virus (RABV) appears to be endemic in Bangui, its epidemiology is in fact shaped by the regular extinction of local chains of transmission coupled with the introduction of new lineages, generating successive waves of spread. Notably, the effective reproduction number during each wave was rarely above the critical value of 1, such that rabies is not self-sustaining in Bangui. In turn, this suggests that rabies at local geographic scales is driven by human-mediated dispersal of RABV among sparsely connected peri-urban and rural areas as opposed to dispersion in a relatively large homogenous urban dog population. This combined epidemiological and genomic approach enables development of a comprehensive framework for understanding disease persistence and informing control measures, indicating that control measures are probably best targeted towards areas neighbouring the city that appear as the source of frequent incursions seeding outbreaks in Bangui. PMID:27058957

  3. Revealing the Micro-scale Signature of Endemic Zoonotic Disease Transmission in an African Urban Setting

    PubMed Central

    Bourhy, Hervé; Nakouné, Emmanuel; Hall, Matthew; Nouvellet, Pierre; Lepelletier, Anthony; Talbi, Chiraz; Watier, Laurence; Holmes, Edward C.; Cauchemez, Simon; Lemey, Philippe; Donnelly, Christl A.; Rambaut, Andrew

    2016-01-01

    The development of novel approaches that combine epidemiological and genomic data provides new opportunities to reveal the spatiotemporal dynamics of infectious diseases and determine the processes responsible for their spread and maintenance. Taking advantage of detailed epidemiological time series and viral sequence data from more than 20 years reported by the National Reference Centre for Rabies of Bangui, the capital city of Central African Republic, we used a combination of mathematical modeling and phylogenetic analysis to determine the spatiotemporal dynamics of rabies in domestic dogs as well as the frequency of extinction and introduction events in an African city. We show that although dog rabies virus (RABV) appears to be endemic in Bangui, its epidemiology is in fact shaped by the regular extinction of local chains of transmission coupled with the introduction of new lineages, generating successive waves of spread. Notably, the effective reproduction number during each wave was rarely above the critical value of 1, such that rabies is not self-sustaining in Bangui. In turn, this suggests that rabies at local geographic scales is driven by human-mediated dispersal of RABV among sparsely connected peri-urban and rural areas as opposed to dispersion in a relatively large homogenous urban dog population. This combined epidemiological and genomic approach enables development of a comprehensive framework for understanding disease persistence and informing control measures, indicating that control measures are probably best targeted towards areas neighbouring the city that appear as the source of frequent incursions seeding outbreaks in Bangui. PMID:27058957

  4. Effect of African- and European-American maternal attitudes and limit-setting strategies on children's self-regulation.

    PubMed

    LeCuyer, Elizabeth A; Swanson, Dena P; Cole, Robert; Kitzman, Harriet

    2011-12-01

    The effect of maternal attitudes and limit-setting strategies on children's self-regulation (measured as committed compliance) was compared in 151 African-American (AA) and 108 European-American (EA) mothers and their 3-year-old children. There were no ethnic differences in children's compliance, however ethnicity moderated the relationship between maternal authoritarian attitudes and children's compliance. Higher authoritarian attitudes predicted less children's compliance in the EA sample, but greater compliance in the AA sample. Observational limit-setting data revealed that in both ethnic groups, maternal authoritarian attitudes influenced children's self-regulation through maternal use of lower-power (gentle) verbal strategies, fewer physical strategies, and judicious use of higher-power verbal strategies. The findings indicate that the meaning and purpose of authoritarian attitudes varies across these mothers' socio-cultural contexts.

  5. How Good Is Good Enough? Educational Standard Setting and Its Effect on African American Test Takers

    ERIC Educational Resources Information Center

    Caines, Jade; Engelhard, George, Jr.

    2012-01-01

    Standard setting (the process of establishing minimum passing scores on high-stakes exams) is a highly evaluative and policy-driven process. It is a common belief that standard setting panels should be diverse and representative. There is concern, however, that panelists with varying characteristics may differentially influence the results of the…

  6. Randomization Methods in Emergency Setting Trials: A Descriptive Review

    ERIC Educational Resources Information Center

    Corbett, Mark Stephen; Moe-Byrne, Thirimon; Oddie, Sam; McGuire, William

    2016-01-01

    Background: Quasi-randomization might expedite recruitment into trials in emergency care settings but may also introduce selection bias. Methods: We searched the Cochrane Library and other databases for systematic reviews of interventions in emergency medicine or urgent care settings. We assessed selection bias (baseline imbalances) in prognostic…

  7. Installation of Ceramic Tile: Residential Thin-Set Methods.

    ERIC Educational Resources Information Center

    Short, Sam

    This curriculum guide contains materials for use in teaching a course on residential thin-set methods of tile installation. Covered in the individual units are the following topics: the tile industry; basic math; tools; measurement; safety in tile setting; installation materials and guidelines for their use; floors; counter tops and backsplashes;…

  8. An efficient MRF embedded level set method for image segmentation.

    PubMed

    Yang, Xi; Gao, Xinbo; Tao, Dacheng; Li, Xuelong; Li, Jie

    2015-01-01

    This paper presents a fast and robust level set method for image segmentation. To enhance the robustness against noise, we embed a Markov random field (MRF) energy function to the conventional level set energy function. This MRF energy function builds the correlation of a pixel with its neighbors and encourages them to fall into the same region. To obtain a fast implementation of the MRF embedded level set model, we explore algebraic multigrid (AMG) and sparse field method (SFM) to increase the time step and decrease the computation domain, respectively. Both AMG and SFM can be conducted in a parallel fashion, which facilitates the processing of our method for big image databases. By comparing the proposed fast and robust level set method with the standard level set method and its popular variants on noisy synthetic images, synthetic aperture radar (SAR) images, medical images, and natural images, we comprehensively demonstrate the new method is robust against various kinds of noises. In particular, the new level set method can segment an image of size 500 × 500 within 3 s on MATLAB R2010b installed in a computer with 3.30-GHz CPU and 4-GB memory.

  9. A Comparative Study of Standard-Setting Methods.

    ERIC Educational Resources Information Center

    Livingston, Samuel A.; Zieky, Michael J.

    1989-01-01

    The borderline group standard-setting method (BGSM), Nedelsky method (NM), and Angoff method (AM) were compared, using reading scores for 1,948 and mathematics scores for 2,191 sixth through ninth graders. The NM and AM were inconsistent with the BGSM. Passing scores were higher where students were more able. (SLD)

  10. A Comparison of Bookmark and Angoff Standard Setting Methods

    ERIC Educational Resources Information Center

    Çetin, Sevda; Gelbal, Selahattin

    2013-01-01

    In this research, the cut score of a foundation university was re-calculated with bookmark method and with Angoff method, each of which is a standard setting method; and the cut scores found were compared with the current proficiency score. Thus, the final cut score was found to be 27.87 with the cooperative work of 17 experts through the Angoff…

  11. Fuzzy Set Methods for Object Recognition in Space Applications

    NASA Technical Reports Server (NTRS)

    Keller, James M. (Editor)

    1992-01-01

    Progress on the following four tasks is described: (1) fuzzy set based decision methodologies; (2) membership calculation; (3) clustering methods (including derivation of pose estimation parameters), and (4) acquisition of images and testing of algorithms.

  12. Exploring Household Economic Impacts of Childhood Diarrheal Illnesses in 3 African Settings

    PubMed Central

    Rheingans, Richard; Kukla, Matt; Adegbola, Richard A.; Saha, Debasish; Omore, Richard; Breiman, Robert F.; Sow, Samba O.; Onwuchekwa, Uma; Nasrin, Dilruba; Farag, Tamer H.; Kotloff, Karen L.; Levine, Myron M.

    2012-01-01

    Beyond the morbidity and mortality burden of childhood diarrhea in sub-Saharan African are significant economic costs to affected households. Using survey data from 3 of the 4 sites in sub-Saharan Africa (Gambia, Kenya, Mali) participating in the Global Enteric Multicenter Study (GEMS), we estimated the direct medical, direct nonmedical, and indirect (productivity losses) costs borne by households due to diarrhea in young children. Mean cost per episode was $2.63 in Gambia, $6.24 in Kenya, and $4.11 in Mali. Direct medical costs accounted for less than half of these costs. Mean costs understate the distribution of costs, with 10% of cases exceeding $6.50, $11.05, and $13.84 in Gambia, Kenya, and Mali. In all countries there was a trend toward lower costs among poorer households and in 2 of the countries for diarrheal illness affecting girls. For poor children and girls, this may reflect reduced household investment in care, which may result in increased risks of mortality. PMID:23169944

  13. An Analysis of Teacher Perceptions of African American Boys' Educational Status in a Rural School Setting

    ERIC Educational Resources Information Center

    Bruton, Chantrell Anita

    2012-01-01

    African American boys are the lowest achieving academic group in public schools. Current research has delved into why this occurs and into implications for African American boys and communities. However, current research has focused on this in urban populations and has not looked at length at the status of African American boys in rural…

  14. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

    Wagh, Arun S.; Singh, Dileep; Pullockaran, Jose D.; Knox, Lerry

    1997-01-01

    A method for producing quick setting concrete is provided comprising hydrng a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO.sub.3 of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring.

  15. Experiences and effects of psychiatric stigma: Monologues of the stigmatizers and the stigmatized in an African setting

    PubMed Central

    Egbe, Catherine O.

    2015-01-01

    People with mental illness (PWMI) are faced with a number of social and health-related challenges especially stigma and discrimination which tend to have negative effects on their lives. This paper presents narrative monologues portraying the experiences and effects of psychiatric stigma and discrimination on PWMI in South Africa. These narratives voice out the concerns of the stigmatizers (specifically family members and significant others of PWMI) and the stigmatized in a poetic fashion. The society is still not very sympathetic to the plights of PWMI and this affects their general health and well-being. Traditional beliefs and prejudice still drive public attitude towards PWMI especially in African settings. These narratives presented in a poetic fashion in this paper highlight some salient issues relating to the experience and effects of stigma and the desires of PWMI to be treated with love and respect and helped to lead healthy normal lives. PMID:26088367

  16. Integration of non-communicable diseases in health care: tackling the double burden of disease in African settings.

    PubMed

    Temu, Florence; Leonhardt, Marcus; Carter, Jane; Thiam, Sylla

    2014-01-01

    Sub-Saharan African countries now face the double burden of Non Communicable and Communicable Diseases. This situation represents a major threat to fragile health systems and emphasises the need for innovative integrative approaches to health care delivery. Health services need to be reorganised to address populations' needs holistically and effectively leverage resources in already resource-limited settings. Access and delivery of quality health care should be reinforced and implemented at primary health care level within the framework of health system strengthening. Competencies need to be developed around services provided rather than specific diseases. New models of integration within the health sector and other sectors should be explored and further evidence generated to inform policy and practice to combat the double burden.

  17. Integration of non-communicable diseases in health care: tackling the double burden of disease in African settings.

    PubMed

    Temu, Florence; Leonhardt, Marcus; Carter, Jane; Thiam, Sylla

    2014-01-01

    Sub-Saharan African countries now face the double burden of Non Communicable and Communicable Diseases. This situation represents a major threat to fragile health systems and emphasises the need for innovative integrative approaches to health care delivery. Health services need to be reorganised to address populations' needs holistically and effectively leverage resources in already resource-limited settings. Access and delivery of quality health care should be reinforced and implemented at primary health care level within the framework of health system strengthening. Competencies need to be developed around services provided rather than specific diseases. New models of integration within the health sector and other sectors should be explored and further evidence generated to inform policy and practice to combat the double burden. PMID:25419329

  18. Quick-setting concrete and a method for making quick-setting concrete

    SciTech Connect

    Wagh, A.S.; Singh, D.; Pullockaran, J.D.; Knox, L.

    1995-12-31

    This invention relates to a method for producing concrete, and more specifically, this invention relates to a method for producing quick-setting concrete while simultaneously minimizing the release of carbon dioxide to the atmosphere, said release of carbon dioxide inherent in cement production. A method for producing quick setting concrete comprises hydrating a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO{sub 3} of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring.

  19. An improved level set method for vertebra CT image segmentation

    PubMed Central

    2013-01-01

    Background Clinical diagnosis and therapy for the lumbar disc herniation requires accurate vertebra segmentation. The complex anatomical structure and the degenerative deformations of the vertebrae makes its segmentation challenging. Methods An improved level set method, namely edge- and region-based level set method (ERBLS), is proposed for vertebra CT images segmentation. By considering the gradient information and local region characteristics of images, the proposed model can efficiently segment images with intensity inhomogeneity and blurry or discontinuous boundaries. To reduce the dependency on manual initialization in many active contour models and for an automatic segmentation, a simple initialization method for the level set function is built, which utilizes the Otsu threshold. In addition, the need of the costly re-initialization procedure is completely eliminated. Results Experimental results on both synthetic and real images demonstrated that the proposed ERBLS model is very robust and efficient. Compared with the well-known local binary fitting (LBF) model, our method is much more computationally efficient and much less sensitive to the initial contour. The proposed method has also applied to 56 patient data sets and produced very promising results. Conclusions An improved level set method suitable for vertebra CT images segmentation is proposed. It has the flexibility of segmenting the vertebra CT images with blurry or discontinuous edges, internal inhomogeneity and no need of re-initialization. PMID:23714300

  20. Life Experience of African Graduate Students in a Multi-Cultural Setting: A Case Study.

    ERIC Educational Resources Information Center

    Antwi, Ransford; Ziyati, Abdelali

    A study examined how international students from North and West Africa fit in, cope, manage, and respond to their experiences in American Universities that are in many cases set up in the context of Americans who constitute the majority. Assuming that the lives of international students outside their home countries and cultures are…

  1. Children's Digital Literacy Practices in Unequal South African Settings

    ERIC Educational Resources Information Center

    Lemphane, Polo; Prinsloo, Mastin

    2014-01-01

    Contemporary movements of people and resources across rural and urban settings, city locales and national and regional borders produce challenges for familiar ways of studying languages as located and stable systems and of literacies as standardised ways of reading and writing texts. This study contrasts children's digital communicative…

  2. Stereotype Threat in Manual Labor Settings for African American and Caucasian Participants

    ERIC Educational Resources Information Center

    Flanagan, Jennifer L.; Green, Raymond J.

    2011-01-01

    Stereotype threat has primarily been studied with regard to test performance in academic settings, testing aptitude, ability, and intelligence, and it has been found to cause both behavioral and cognitive decrements. Although there is research on stereotype threat in the workplace, this too is usually conducted in upper-level or more academically…

  3. Mental Illness Stigma Intervention in African Americans: Examining Two Delivery Methods.

    PubMed

    Vinson, Ebony S; Abdullah, Tahirah; Brown, Tamara L

    2016-05-01

    Stigma surrounding mental illness and mental health treatment remains a significant problem, particularly among African Americans. This study sought to examine the effects of 2 intervention delivery methods in reducing reported stigma. African Americans (n = 158) were nonrandomly assigned to an in-person contact or video condition and administered a survey immediately before, after, and 2 weeks following the stigma intervention. The in vivo contact condition consisted of an African American man discussing his experiences with mental illness and psychotherapy. The session was recorded, and the recording was used for the video condition. There were no significant effects based on delivery method; however, there was a significant effect for time on stigma and help-seeking attitude measures. Further research is needed to determine the overall effectiveness of the intervention. PMID:27078010

  4. Mental Illness Stigma Intervention in African Americans: Examining Two Delivery Methods.

    PubMed

    Vinson, Ebony S; Abdullah, Tahirah; Brown, Tamara L

    2016-05-01

    Stigma surrounding mental illness and mental health treatment remains a significant problem, particularly among African Americans. This study sought to examine the effects of 2 intervention delivery methods in reducing reported stigma. African Americans (n = 158) were nonrandomly assigned to an in-person contact or video condition and administered a survey immediately before, after, and 2 weeks following the stigma intervention. The in vivo contact condition consisted of an African American man discussing his experiences with mental illness and psychotherapy. The session was recorded, and the recording was used for the video condition. There were no significant effects based on delivery method; however, there was a significant effect for time on stigma and help-seeking attitude measures. Further research is needed to determine the overall effectiveness of the intervention.

  5. Quick-setting concrete and a method for making quick-setting concrete

    DOEpatents

    Wagh, A.S.; Singh, D.; Pullockaran, J.D.; Knox, L.

    1997-04-29

    A method for producing quick setting concrete is provided comprising mixing a concrete dry mixture with carbonate solution to create a slurry, and allowing the slurry to cure. The invention also provides for a quick setting concrete having a predetermined proportion of CaCO{sub 3} of between 5 and 23 weight percent of the entire concrete mixture, and whereby the concrete has a compression strength of approximately 4,000 pounds per square inch (psi) within 24 hours after pouring. 2 figs.

  6. Professionals' Perceptions about the Need for Pain Management Interventions for Children with Cerebral Palsy in South African School Settings.

    PubMed

    Nilsson, Stefan; Johnson, Ensa; Adolfsson, Margareta

    2016-08-01

    Pain is common in children with cerebral palsy (CP) and may have negative consequences for children's success in their studies. Research has shown that pain in childhood negatively influences individuals' participation and quality of life in later years. This study investigated how professionals in South African school settings respond to children's need for pain management in an attempt to enable the children to be active participants in school activities, despite their pain. The study was descriptive and followed a qualitative design (i.e., focus group interviews with semistructured questions and a conventional content analysis). Five government schools for children with special education needs in South Africa's Gauteng province participated. Participants/Subjects: Thirty-eight professionals who represented eight professions. Professional statements on the topic were collected from five focus group sessions conducted during one week. Qualitative content analysis of the data was performed. Similar statements were combined, coded, and sorted into main categories and subcategories. The analysis identified three main categories for pain management: environmental, treatment, and support strategies. In addition, four groups of statements emerged on how contextual factors might affect pain in children with CP and their participation in school settings. It is important to train professionals in pain management and to implement structured models for pain prevention and management to ensure that best practices are adhered to for children with CP who suffer from acute or chronic pain. PMID:27349380

  7. Qualitative research: Observational methods in health care settings.

    PubMed Central

    Mays, N.; Pope, C.

    1995-01-01

    Clinicians used to observing individual patients, and epidemiologists trained to observe the course of disease, may be forgiven for misunderstanding the term observational method as used in qualitative research. In contrast to the clinician or epidemiologist, the qualitative researcher systematically watches people and events to find out about behaviours and interactions in natural settings. Observation, in this sense, epitomises the idea of the researcher as the research instrument. It involves "going into the field"--describing and analysing what has been seen. In health care settings this method has been insightful and illuminating, but it is not without pitfalls for the unprepared researcher. Images p183-a PMID:7613435

  8. Mapping the African thunderstorm center in absolute units using Schumann resonance spectral decomposition method

    NASA Astrophysics Data System (ADS)

    Dyrda, Michal; Kulak, Andrzej; Mlynarczyk, Janusz

    2015-04-01

    Monitoring of the global lightning activity provides a very useful tool to study the global warming phenomenon and the other longer-scale climate changes induced by humans. The lightning activity is measured using various observational methods form space (optical satellite observations) as well as from the ground mostly by VLF /LF lightning detection networks, i.e. World Wide Lightning Location Network (WWLLN) or lightning detection network (LINET) in Europe. However, the global lightning activity measurements are possible only in the ELF range. Here we examine the African thunderstorm activity center, which is the most violent and active one. In a spherical damped resonator, such as the Earth-ionosphere cavity, the electromagnetic field is described by the solution of an inhomogeneous wave equation. For such equation the general solution can be expressed by the superposition of the solutions of the homogeneous equation, describing the resonance field, and the component, which is quite strong close to the source and weakens with source-observer separation. Thus, the superposition of the standing wave field with the field of traveling waves, which supply the energy from the lighting discharges to the global resonator, is a main reason for an asymmetric shape of the observational Schumann resonance (SR) power spectra, which highly deviate from the Lorentz curves. It is possible to separate this component from the signal using the spectrum decomposition method proposed by Kułak et al. [2006]. In our approach, we apply the inverse problem solution for determining the distance of the dominant lightning source. The distances to the thunderstorm centers are calculated using the analytical models for the electromagnetic waves propagation in the Earth-ionosphere cavity. Such forms of analytic solutions of the resonant field in the spherical cavity is the zonal harmonic series representation, described by Mushtak and Williams [2002] and we calculated the sets of such curves

  9. Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi

    PubMed Central

    King, Carina; Hall, Jenny; Banda, Masford; Beard, James; Bird, Jon; Kazembe, Peter; Fottrell, Ed

    2014-01-01

    Background As hardware for electronic data capture (EDC), such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing. Objective We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect), one for PALM and Windows OS (Pendragon), and a custom-built application for Android (Mobile InterVA – MIVA). Design We report on the personal field and development experience of fieldworkers, project managers, and EDC system developers. Results Fieldworkers preferred using EDC to paper-based systems, although some struggled with the technology at first. Highlighted features include in-built skip patterns for all systems, and specifically the ‘case’ function that CommCare offers. MIVA as a standalone app required considerably more time and expertise than the other systems to create and could not be customised for our specific research needs; however, it facilitates standardised routine data collection. CommCare and ODK Collect both have user-friendly web-interfaces for form development and good technical support. CommCare requires Internet to build an application and download it to a device, whereas all steps can be done offline with ODK Collect, a desirable feature in low connectivity settings. Pendragon required more complex programming of logic, using a Microsoft Access application, and generally had less technical support. Start-up costs varied between systems, and all were considered more expensive than setting up a paper-based system; however running costs were generally low and therefore thought to be cost-effective over the course of our projects. Conclusions EDC offers many opportunities for efficient data collection, but brings some issues requiring consideration when designing a study; the decision of which hardware and software to use

  10. DEVELOPING AND EXPLOITING A UNIQUE SEISMIC DATA SET FROM SOUTH AFRICAN GOLD MINES FOR SOURCE CHARACTERIZATION AND WAVE PROPAGATION

    SciTech Connect

    Julia, J; Nyblade, A A; Gok, R; Walter, W R; Linzer, L; Durrheim, R

    2008-07-08

    In this project, we are developing and exploiting a unique seismic data set to address the characteristics of small seismic events and the associated seismic signals observed at local (< 200 km) and regional (< 2000 km) distances. The dataset is being developed using mining-induced events from 3 deep gold mines in South Africa recorded on inmine networks (< 1 km) comprised of tens of high-frequency sensors, a network of 4 broadband stations installed as part of this project at the surface around the mines (1-10 km), and a network of existing broadband seismic stations at local/regional distances (50-1000 km) from the mines. After 1 year of seismic monitoring of mine activity (2007), over 10,000 events in the range -3.4 < ML < 4.4 have been catalogued and recorded by the in-mine networks. Events with positive magnitudes are generally well recorded by the surface-mine stations, while magnitudes 3.0 and larger are seen at regional distances (up to {approx}600 km) in high-pass filtered recordings. We have analyzed in-mine recordings in detail at one of the South African mines (Savuka) to (i) improve on reported hypocentral locations, (ii) verify sensor orientations, and (iii) determine full moment tensor solutions. Hypocentral relocations on all catalogued events have been obtained from P- and S-wave travel-times reported by the mine network operator through an automated procedure that selects travel-times falling on Wadati lines with slopes in the 0.6-0.7 range; sensor orientations have been verified and, when possible, corrected by correlating P-, SV-, and SH-waveforms obtained from theoretical and empirical (polarization filter) rotation angles; full moment tensor solutions have been obtained by inverting P-, SV-, and SH- spectral amplitudes measured on the theoretically rotated waveforms with visually assigned polarities. The relocation procedure has revealed that origin times often necessitate a negative correction of a few tenths of second and that hypocentral

  11. Optimizing distance-based methods for large data sets

    NASA Astrophysics Data System (ADS)

    Scholl, Tobias; Brenner, Thomas

    2015-10-01

    Distance-based methods for measuring spatial concentration of industries have received an increasing popularity in the spatial econometrics community. However, a limiting factor for using these methods is their computational complexity since both their memory requirements and running times are in {{O}}(n^2). In this paper, we present an algorithm with constant memory requirements and shorter running time, enabling distance-based methods to deal with large data sets. We discuss three recent distance-based methods in spatial econometrics: the D&O-Index by Duranton and Overman (Rev Econ Stud 72(4):1077-1106, 2005), the M-function by Marcon and Puech (J Econ Geogr 10(5):745-762, 2010) and the Cluster-Index by Scholl and Brenner (Reg Stud (ahead-of-print):1-15, 2014). Finally, we present an alternative calculation for the latter index that allows the use of data sets with millions of firms.

  12. A model for selecting assessment methods for evaluating medical students in African medical schools.

    PubMed

    Walubo, Andrew; Burch, Vanessa; Parmar, Paresh; Raidoo, Deshandra; Cassimjee, Mariam; Onia, Rudy; Ofei, Francis

    2003-09-01

    Introduction of more effective and standardized assessment methods for testing students' performance in Africa's medical institutions has been hampered by severe financial and personnel shortages. Nevertheless, some African institutions have recognized the problem and are now revising their medical curricula, and, therefore, their assessment methods. These institutions, and those yet to come, need guidance on selecting assessment methods so as to adopt models that can be sustained locally. The authors provide a model for selecting assessment methods for testing medical students' performance in African medical institutions. The model systematically evaluates factors that influence implementation of an assessment method. Six commonly used methods (the essay examinations, short-answer questions, multiple-choice questions, patient-based clinical examination, problem-based oral examination [POE], and objective structured clinical examination) are evaluated by scoring and weighting against performance, cost, suitability, and safety factors. In the model, the highest score identifies the most appropriate method. Selection of an assessment method is illustrated using two institutional models, one depicting an ideal situation in which the objective structured clinical examination was preferred, and a second depicting the typical African scenario in which the essay and short-answer-question examinations were best. The POE method received the highest score and could be recommended as the most appropriate for Africa's medical institutions, but POE assessments require changing the medical curricula to a problem-based learning approach. The authors' model is easy to understand and promotes change in the medical curriculum and method of student assessment.

  13. Implementing oral care to reduce aspiration pneumonia amongst patients with dysphagia in a South African setting.

    PubMed

    Seedat, Jaishika; Penn, Claire

    2016-01-01

    Oral care is a crucial routine for patients with dysphagia that, when completed routinely, can prevent the development of aspiration pneumonia. There is no standardised protocol for oral care within government hospitals in South Africa. This study aimed to investigate the outcome of an oral care protocol. Participants were patients with oropharyngeal dysphagia, with either stroke or traumatic brain injury as the underlying medical pathology, and nurses. All participants were recruited from one tertiary level government hospital in Gauteng, South Africa. 139 nurses participated in the study and received training on the oral care protocol. There were two groups of participants with oropharyngeal dysphagia. Group one (study group, n = 23) was recruited by consecutive sampling, received regular oral care and were not restricted from drinking water; however, all other liquids were restricted. Group two (comparison group, n = 23) was recruited via a retrospective record review, received inconsistent oral care and were placed on thickened liquids or liquid restricted diets. Results showed that a regimen of regular oral care and free water provision when combined with dysphagia intervention did prevent aspiration pneumonia in patients with oropharyngeal dysphagia. The article highlights two key findings: that regular and routine oral care is manageable within an acute government hospital context and a strict routine of oral care can reduce aspiration pneumonia in patients with oropharyngeal dysphagia. An implication from these findings is confirmation that teamwork in acute care settings in developing contexts must be prioritised to improve dysphagia management and patient prognosis. PMID:26974243

  14. Implementing oral care to reduce aspiration pneumonia amongst patients with dysphagia in a South African setting.

    PubMed

    Seedat, Jaishika; Penn, Claire

    2016-01-01

    Oral care is a crucial routine for patients with dysphagia that, when completed routinely, can prevent the development of aspiration pneumonia. There is no standardised protocol for oral care within government hospitals in South Africa. This study aimed to investigate the outcome of an oral care protocol. Participants were patients with oropharyngeal dysphagia, with either stroke or traumatic brain injury as the underlying medical pathology, and nurses. All participants were recruited from one tertiary level government hospital in Gauteng, South Africa. 139 nurses participated in the study and received training on the oral care protocol. There were two groups of participants with oropharyngeal dysphagia. Group one (study group, n = 23) was recruited by consecutive sampling, received regular oral care and were not restricted from drinking water; however, all other liquids were restricted. Group two (comparison group, n = 23) was recruited via a retrospective record review, received inconsistent oral care and were placed on thickened liquids or liquid restricted diets. Results showed that a regimen of regular oral care and free water provision when combined with dysphagia intervention did prevent aspiration pneumonia in patients with oropharyngeal dysphagia. The article highlights two key findings: that regular and routine oral care is manageable within an acute government hospital context and a strict routine of oral care can reduce aspiration pneumonia in patients with oropharyngeal dysphagia. An implication from these findings is confirmation that teamwork in acute care settings in developing contexts must be prioritised to improve dysphagia management and patient prognosis.

  15. The Learning Environment and the Reading Achievement of Middle School African American Male Students in a Suburban School Setting

    ERIC Educational Resources Information Center

    Frazier, Nicole Denise

    2012-01-01

    The reading achievement of African American males might be impacted by a host of variables. This study was undertaken to determine if there was a difference in the culturally responsive characteristics present in the learning environment of a middle school and the reading achievement of middle school African American males. The purpose of this…

  16. Illinois Secondary Principals' Perceptions and Expectations Concerning Students Who Use African American Vernacular English in an Academic Setting

    ERIC Educational Resources Information Center

    McClendon, Garrard Overton

    2010-01-01

    This study investigates principals' individual and aggregate perceptions of and expectations for students who use African American Vernacular English. Using the African American English Teacher Attitude Scale (AAETAS), the study seeks to describe the relationship between principals' demographic characteristics and their perceptions of African…

  17. SET: a pupil detection method using sinusoidal approximation.

    PubMed

    Javadi, Amir-Homayoun; Hakimi, Zahra; Barati, Morteza; Walsh, Vincent; Tcheang, Lili

    2015-01-01

    Mobile eye-tracking in external environments remains challenging, despite recent advances in eye-tracking software and hardware engineering. Many current methods fail to deal with the vast range of outdoor lighting conditions and the speed at which these can change. This confines experiments to artificial environments where conditions must be tightly controlled. Additionally, the emergence of low-cost eye tracking devices calls for the development of analysis tools that enable non-technical researchers to process the output of their images. We have developed a fast and accurate method (known as "SET") that is suitable even for natural environments with uncontrolled, dynamic and even extreme lighting conditions. We compared the performance of SET with that of two open-source alternatives by processing two collections of eye images: images of natural outdoor scenes with extreme lighting variations ("Natural"); and images of less challenging indoor scenes ("CASIA-Iris-Thousand"). We show that SET excelled in outdoor conditions and was faster, without significant loss of accuracy, indoors. SET offers a low cost eye-tracking solution, delivering high performance even in challenging outdoor environments. It is offered through an open-source MATLAB toolkit as well as a dynamic-link library ("DLL"), which can be imported into many programming languages including C# and Visual Basic in Windows OS (www.eyegoeyetracker.co.uk). PMID:25914641

  18. "It's my secret": barriers to paediatric HIV treatment in a poor rural South African setting.

    PubMed

    Kimani-Murage, E W; Manderson, L; Norris, S A; Kahn, K

    2013-01-01

    In South Africa, a third of children born are exposed to HIV, while fewer undergo an HIV confirmatory test. Anti-retroviral therapy (ART) coverage among children remains low-despite roll-out of the national ART programme in South Africa in 2004. This study sought to understand critical barriers to seeking HIV-related care for children in rural South Africa. Data presented in this article derive from community-based qualitative research in poor rural villages in north-east South Africa; this includes 21 in-depth interviews in 2008 among caregivers of children identified as HIV-positive in 2007 from a randomly selected community-based sample. Using NVIVO 8, data were coded and analysed, using a constant comparative method to identify themes and their repetitions and variations. Structural barriers leading to poor access to health care, and social and systems barriers, all influenced paediatric HIV treatment seeking. Of concern was the expressed need to maintain secrecy regarding a child's HIV status to avoid stigma and discrimination, and misconceptions regarding the course of HIV disease in children; this led to a delay in seeking appropriate care. These barriers need to be addressed, including through focused awareness campaigns, improved access to health care and interventions to address rural poverty and development at both household and community levels. In addition, training of health care professionals to improve their attitudes and practice may be necessary. However, this study only provides the perspective of the caregivers; further studies with health care providers are needed to gain a fuller picture for appropriate policy and practice guidance.

  19. "It's my secret": barriers to paediatric HIV treatment in a poor rural South African setting.

    PubMed

    Kimani-Murage, E W; Manderson, L; Norris, S A; Kahn, K

    2013-01-01

    In South Africa, a third of children born are exposed to HIV, while fewer undergo an HIV confirmatory test. Anti-retroviral therapy (ART) coverage among children remains low-despite roll-out of the national ART programme in South Africa in 2004. This study sought to understand critical barriers to seeking HIV-related care for children in rural South Africa. Data presented in this article derive from community-based qualitative research in poor rural villages in north-east South Africa; this includes 21 in-depth interviews in 2008 among caregivers of children identified as HIV-positive in 2007 from a randomly selected community-based sample. Using NVIVO 8, data were coded and analysed, using a constant comparative method to identify themes and their repetitions and variations. Structural barriers leading to poor access to health care, and social and systems barriers, all influenced paediatric HIV treatment seeking. Of concern was the expressed need to maintain secrecy regarding a child's HIV status to avoid stigma and discrimination, and misconceptions regarding the course of HIV disease in children; this led to a delay in seeking appropriate care. These barriers need to be addressed, including through focused awareness campaigns, improved access to health care and interventions to address rural poverty and development at both household and community levels. In addition, training of health care professionals to improve their attitudes and practice may be necessary. However, this study only provides the perspective of the caregivers; further studies with health care providers are needed to gain a fuller picture for appropriate policy and practice guidance. PMID:23244783

  20. Efficient molecular surface generation using level-set methods.

    PubMed

    Can, Tolga; Chen, Chao-I; Wang, Yuan-Fang

    2006-12-01

    Molecules interact through their surface residues. Calculation of the molecular surface of a protein structure is thus an important step for a detailed functional analysis. One of the main considerations in comparing existing methods for molecular surface computations is their speed. Most of the methods that produce satisfying results for small molecules fail to do so for large complexes. In this article, we present a level-set-based approach to compute and visualize a molecular surface at a desired resolution. The emerging level-set methods have been used for computing evolving boundaries in several application areas from fluid mechanics to computer vision. Our method provides a uniform framework for computing solvent-accessible, solvent-excluded surfaces and interior cavities. The computation is carried out very efficiently even for very large molecular complexes with tens of thousands of atoms. We compared our method to some of the most widely used molecular visualization tools (Swiss-PDBViewer, PyMol, and Chimera) and our results show that we can calculate and display a molecular surface 1.5-3.14 times faster on average than all three of the compared programs. Furthermore, we demonstrate that our method is able to detect all of the interior inaccessible cavities that can accommodate one or more water molecules. PMID:16621636

  1. Acceptability of donated breast milk in a resource limited South African setting

    PubMed Central

    2011-01-01

    Background The importance of breast milk for infants' growth, development and overall health is widely recognized. In situations where women are not able to provide their infants with sufficient amounts of their own breast milk, donor breast milk is the next preferred option. Although there is considerable research on the safety and scientific aspects of donor milk, and the motivations and experiences of donors, there is limited research addressing the attitudes and experiences of the women and families whose infants receive this milk. This study therefore examined attitudes towards donated breast milk among mothers, families and healthcare providers of potential recipient infants. Methods The study was conducted at a public hospital and nearby clinic in Durban, South Africa. The qualitative data was derived from eight focus group discussions which included four groups with mothers; one with male partners; and one with grandmothers, investigating attitudes towards receiving donated breast milk for infants. There was also one group each with nurses and doctors about their attitudes towards donated breast milk and its use in the hospital. The focus groups were conducted in September and October 2009 and each group had between four and eleven participants, leading to a total of 48 participants. Results Although breast milk was seen as important to child health there were concerns about undermining of breast milk because of concerns about HIV and marketing and promotion of formula milks. In addition there were concerns about the safety of donor breast milk and discomfort about using another mother's milk. Participants believed that education on the importance of breast milk and transparency on the processes involved in sourcing and preparing donor milk would improve the acceptability. Conclusions This study has shown that there are obstacles to the acceptability of donor milk, mainly stemming from lack of awareness/familiarity with the processes around donor breast

  2. Improvements to Level Set, Immersed Boundary methods for Interface Tracking

    NASA Astrophysics Data System (ADS)

    Vogl, Chris; Leveque, Randy

    2014-11-01

    It is not uncommon to find oneself solving a moving boundary problem under flow in the context of some application. Of particular interest is when the moving boundary exerts a curvature-dependent force on the liquid. Such a force arises when observing a boundary that is resistant to bending or has surface tension. Numerically speaking, stable numerical computation of the curvature can be difficult as it is often described in terms of high-order derivatives of either marker particle positions or of a level set function. To address this issue, the level set method is modified to track not only the position of the boundary, but the curvature as well. The definition of the signed-distance function that is used to modify the level set method is also used to develop an interpolation-free, closest-point method. These improvements are used to simulate a bending-resistant, inextensible boundary under shear flow to highlight area and volume conservation, as well as stable curvature calculation. Funded by a NSF MSPRF grant.

  3. GenoSets: Visual Analytic Methods for Comparative Genomics

    PubMed Central

    Cain, Aurora A.; Kosara, Robert; Gibas, Cynthia J.

    2012-01-01

    Many important questions in biology are, fundamentally, comparative, and this extends to our analysis of a growing number of sequenced genomes. Existing genomic analysis tools are often organized around literal views of genomes as linear strings. Even when information is highly condensed, these views grow cumbersome as larger numbers of genomes are added. Data aggregation and summarization methods from the field of visual analytics can provide abstracted comparative views, suitable for sifting large multi-genome datasets to identify critical similarities and differences. We introduce a software system for visual analysis of comparative genomics data. The system automates the process of data integration, and provides the analysis platform to identify and explore features of interest within these large datasets. GenoSets borrows techniques from business intelligence and visual analytics to provide a rich interface of interactive visualizations supported by a multi-dimensional data warehouse. In GenoSets, visual analytic approaches are used to enable querying based on orthology, functional assignment, and taxonomic or user-defined groupings of genomes. GenoSets links this information together with coordinated, interactive visualizations for both detailed and high-level categorical analysis of summarized data. GenoSets has been designed to simplify the exploration of multiple genome datasets and to facilitate reasoning about genomic comparisons. Case examples are included showing the use of this system in the analysis of 12 Brucella genomes. GenoSets software and the case study dataset are freely available at http://genosets.uncc.edu. We demonstrate that the integration of genomic data using a coordinated multiple view approach can simplify the exploration of large comparative genomic data sets, and facilitate reasoning about comparisons and features of interest. PMID:23056299

  4. GenoSets: visual analytic methods for comparative genomics.

    PubMed

    Cain, Aurora A; Kosara, Robert; Gibas, Cynthia J

    2012-01-01

    Many important questions in biology are, fundamentally, comparative, and this extends to our analysis of a growing number of sequenced genomes. Existing genomic analysis tools are often organized around literal views of genomes as linear strings. Even when information is highly condensed, these views grow cumbersome as larger numbers of genomes are added. Data aggregation and summarization methods from the field of visual analytics can provide abstracted comparative views, suitable for sifting large multi-genome datasets to identify critical similarities and differences. We introduce a software system for visual analysis of comparative genomics data. The system automates the process of data integration, and provides the analysis platform to identify and explore features of interest within these large datasets. GenoSets borrows techniques from business intelligence and visual analytics to provide a rich interface of interactive visualizations supported by a multi-dimensional data warehouse. In GenoSets, visual analytic approaches are used to enable querying based on orthology, functional assignment, and taxonomic or user-defined groupings of genomes. GenoSets links this information together with coordinated, interactive visualizations for both detailed and high-level categorical analysis of summarized data. GenoSets has been designed to simplify the exploration of multiple genome datasets and to facilitate reasoning about genomic comparisons. Case examples are included showing the use of this system in the analysis of 12 Brucella genomes. GenoSets software and the case study dataset are freely available at http://genosets.uncc.edu. We demonstrate that the integration of genomic data using a coordinated multiple view approach can simplify the exploration of large comparative genomic data sets, and facilitate reasoning about comparisons and features of interest.

  5. Methods for assessing the vulnerability of African fisheries resources to climate change.

    SciTech Connect

    Hlohowskyj, I.; Brody, M. S.; Lackey, R. T.; Environmental Assessment; EPA

    1996-02-01

    Because of the dietary and financial importance of fisheries resources in many African countries, concerns have been expressed regarding the potential for adverse impacts to fisheries resources from climate change, and a need has been identified for assessment tools that can evaluate the potential for impacts in a timely and cost-effective manner. This paper presents a framework and set of methods for assessing the potential effects of climate change on fisheries resources in Africa. The framework identifies the need to first link predicted climate changes to changes in the aquatic environment, and only then can potential impacts to aquatic resources be evaluated. The approach developed for Africa was constrained by several factors, including availability of existing data and assessment technologies, and the need for a rapid evaluation of potential climate impacts. The assessment approach employs a variety of methods including empirical models which predict changes in mortality, maximum sustainable yield, and yearly catch, a bioenergetics model, and a habitat suitability model. Previously developed or newly derived site-specific empirical models can be used to compare mortality, yield, and annual catch estimates among historic, current, and predicted climate conditions. Similarly, bioenergetics modeling can be used to compare growth rates and biomass production among different climate conditions. Habitat suitability models can be developed for current climate conditions, and the effects of changes in climate-driven habitat variables such as water depth, temperature, and current velocity on habitat suitability can be evaluated for different climate conditions. Use of these approaches is recommended because they can utilize existing ecological data and do not require extensive new data collection activities, they are not technologically complex, and they can provide evaluations of potential climate change impacts in a timely and cost-effective manner.

  6. A level-set method for interfacial flows with surfactant

    NASA Astrophysics Data System (ADS)

    Xu, Jian-Jun; Li, Zhilin; Lowengrub, John; Zhao, Hongkai

    2006-03-01

    A level-set method for the simulation of fluid interfaces with insoluble surfactant is presented in two-dimensions. The method can be straightforwardly extended to three-dimensions and to soluble surfactants. The method couples a semi-implicit discretization for solving the surfactant transport equation recently developed by Xu and Zhao [J. Xu, H. Zhao. An Eulerian formulation for solving partial differential equations along a moving interface, J. Sci. Comput. 19 (2003) 573-594] with the immersed interface method originally developed by LeVeque and Li and [R. LeVeque, Z. Li. The immersed interface method for elliptic equations with discontinuous coefficients and singular sources, SIAM J. Numer. Anal. 31 (1994) 1019-1044] for solving the fluid flow equations and the Laplace-Young boundary conditions across the interfaces. Novel techniques are developed to accurately conserve component mass and surfactant mass during the evolution. Convergence of the method is demonstrated numerically. The method is applied to study the effects of surfactant on single drops, drop-drop interactions and interactions among multiple drops in Stokes flow under a steady applied shear. Due to Marangoni forces and to non-uniform Capillary forces, the presence of surfactant results in larger drop deformations and more complex drop-drop interactions compared to the analogous cases for clean drops. The effects of surfactant are found to be most significant in flows with multiple drops. To our knowledge, this is the first time that the level-set method has been used to simulate fluid interfaces with surfactant.

  7. SET: a pupil detection method using sinusoidal approximation

    PubMed Central

    Javadi, Amir-Homayoun; Hakimi, Zahra; Barati, Morteza; Walsh, Vincent; Tcheang, Lili

    2015-01-01

    Mobile eye-tracking in external environments remains challenging, despite recent advances in eye-tracking software and hardware engineering. Many current methods fail to deal with the vast range of outdoor lighting conditions and the speed at which these can change. This confines experiments to artificial environments where conditions must be tightly controlled. Additionally, the emergence of low-cost eye tracking devices calls for the development of analysis tools that enable non-technical researchers to process the output of their images. We have developed a fast and accurate method (known as “SET”) that is suitable even for natural environments with uncontrolled, dynamic and even extreme lighting conditions. We compared the performance of SET with that of two open-source alternatives by processing two collections of eye images: images of natural outdoor scenes with extreme lighting variations (“Natural”); and images of less challenging indoor scenes (“CASIA-Iris-Thousand”). We show that SET excelled in outdoor conditions and was faster, without significant loss of accuracy, indoors. SET offers a low cost eye-tracking solution, delivering high performance even in challenging outdoor environments. It is offered through an open-source MATLAB toolkit as well as a dynamic-link library (“DLL”), which can be imported into many programming languages including C# and Visual Basic in Windows OS (www.eyegoeyetracker.co.uk). PMID:25914641

  8. Interface Surface Area Tracking for the Conservative Level Set Method

    NASA Astrophysics Data System (ADS)

    Firehammer, Stephanie; Desjardins, Olivier

    2015-11-01

    One key question in liquid-gas flows is how to model the interface between phases in a way that is mass, momentum, and energy conserving. The accurate conservative level set (ACLS) method of Desjardins et al. provides a tool for tracking a liquid-gas interface with minimal mass conservation issues; however, it does not explicitly compute the interface surface area and thus nothing can be said a priori about the balance between kinetic energy and surface energy. This work examines an equation for the transport of interface surface area density, which can be written in terms of the gradient of the volume fraction. Furthermore this presentation will outline a numerical method for jointly transporting a conservative level set and surface area density. Finally, we will explore oppportunities for energy conservation via the accurate exchange of energy between the flow field and the interface through surface tension, with test cases to show the results of our extended ACLS method. Funding from the National Science Foundation is gratefully acknowledged.

  9. Methods for assessing movement path recursion with application to African buffalo in South Africa

    USGS Publications Warehouse

    Bar-David, S.; Bar-David, I.; Cross, P.C.; Ryan, S.J.; Knechtel, C.U.; Getz, W.M.

    2009-01-01

    Recent developments of automated methods for monitoring animal movement, e.g., global positioning systems (GPS) technology, yield high-resolution spatiotemporal data. To gain insights into the processes creating movement patterns, we present two new techniques for extracting information from these data on repeated visits to a particular site or patch ("recursions"). Identification of such patches and quantification of recursion pathways, when combined with patch-related ecological data, should contribute to our understanding of the habitat requirements of large herbivores, of factors governing their space-use patterns, and their interactions with the ecosystem. We begin by presenting output from a simple spatial model that simulates movements of large-herbivore groups based on minimal parameters: resource availability and rates of resource recovery after a local depletion. We then present the details of our new techniques of analyses (recursion analysis and circle analysis) and apply them to data generated by our model, as well as two sets of empirical data on movements of African buffalo (Syncerus coffer): the first collected in Klaserie Private Nature Reserve and the second in Kruger National Park, South Africa. Our recursion analyses of model outputs provide us with a basis for inferring aspects of the processes governing the production of buffalo recursion patterns, particularly the potential influence of resource recovery rate. Although the focus of our simulations was a comparison of movement patterns produced by different resource recovery rates, we conclude our paper with a comprehensive discussion of how recursion analyses can be used when appropriate ecological data are available to elucidate various factors influencing movement. Inter alia, these include the various limiting and preferred resources, parasites, and topographical and landscape factors. ?? 2009 by the Ecological Society of America.

  10. Fuzzy set methods for object recognition in space applications

    NASA Technical Reports Server (NTRS)

    Keller, James M.

    1991-01-01

    During the reporting period, the development of the theory and application of methodologies for decision making under uncertainty was addressed. Two subreports are included; the first on properties of general hybrid operators, while the second considers some new research on generalized threshold logic units. In the first part, the properties of the additive gamma-model, where the intersection part is first considered to be the product of the input values and the union part is obtained by an extension of De Morgan's law to fuzzy sets, is explored. Then the Yager's class of union and intersection is used in the additive gamma-model. The inputs are weighted to some power that represents their importance and thus their contribution to the compensation process. In the second part, the extension of binary logic synthesis methods to multiple valued logic synthesis methods to enable the synthesis of decision networks when the input/output variables are not binary is discussed.

  11. A Hybrid Method for Pancreas Extraction from CT Image Based on Level Set Methods

    PubMed Central

    Tan, Hanqing; Fujita, Hiroshi

    2013-01-01

    This paper proposes a novel semiautomatic method to extract the pancreas from abdominal CT images. Traditional level set and region growing methods that request locating initial contour near the final boundary of object have problem of leakage to nearby tissues of pancreas region. The proposed method consists of a customized fast-marching level set method which generates an optimal initial pancreas region to solve the problem that the level set method is sensitive to the initial contour location and a modified distance regularized level set method which extracts accurate pancreas. The novelty in our method is the proper selection and combination of level set methods, furthermore an energy-decrement algorithm and an energy-tune algorithm are proposed to reduce the negative impact of bonding force caused by connected tissue whose intensity is similar with pancreas. As a result, our method overcomes the shortages of oversegmentation at weak boundary and can accurately extract pancreas from CT images. The proposed method is compared to other five state-of-the-art medical image segmentation methods based on a CT image dataset which contains abdominal images from 10 patients. The evaluated results demonstrate that our method outperforms other methods by achieving higher accuracy and making less false segmentation in pancreas extraction. PMID:24066016

  12. A hybrid method for pancreas extraction from CT image based on level set methods.

    PubMed

    Jiang, Huiyan; Tan, Hanqing; Fujita, Hiroshi

    2013-01-01

    This paper proposes a novel semiautomatic method to extract the pancreas from abdominal CT images. Traditional level set and region growing methods that request locating initial contour near the final boundary of object have problem of leakage to nearby tissues of pancreas region. The proposed method consists of a customized fast-marching level set method which generates an optimal initial pancreas region to solve the problem that the level set method is sensitive to the initial contour location and a modified distance regularized level set method which extracts accurate pancreas. The novelty in our method is the proper selection and combination of level set methods, furthermore an energy-decrement algorithm and an energy-tune algorithm are proposed to reduce the negative impact of bonding force caused by connected tissue whose intensity is similar with pancreas. As a result, our method overcomes the shortages of oversegmentation at weak boundary and can accurately extract pancreas from CT images. The proposed method is compared to other five state-of-the-art medical image segmentation methods based on a CT image dataset which contains abdominal images from 10 patients. The evaluated results demonstrate that our method outperforms other methods by achieving higher accuracy and making less false segmentation in pancreas extraction.

  13. Randomization methods in emergency setting trials: a descriptive review

    PubMed Central

    Moe‐Byrne, Thirimon; Oddie, Sam; McGuire, William

    2015-01-01

    Background Quasi‐randomization might expedite recruitment into trials in emergency care settings but may also introduce selection bias. Methods We searched the Cochrane Library and other databases for systematic reviews of interventions in emergency medicine or urgent care settings. We assessed selection bias (baseline imbalances) in prognostic indicators between treatment groups in trials using true randomization versus trials using quasi‐randomization. Results Seven reviews contained 16 trials that used true randomization and 11 that used quasi‐randomization. Baseline group imbalance was identified in four trials using true randomization (25%) and in two quasi‐randomized trials (18%). Of the four truly randomized trials with imbalance, three concealed treatment allocation adequately. Clinical heterogeneity and poor reporting limited the assessment of trial recruitment outcomes. Conclusions We did not find strong or consistent evidence that quasi‐randomization is associated with selection bias more often than true randomization. High risk of bias judgements for quasi‐randomized emergency studies should therefore not be assumed in systematic reviews. Clinical heterogeneity across trials within reviews, coupled with limited availability of relevant trial accrual data, meant it was not possible to adequately explore the possibility that true randomization might result in slower trial recruitment rates, or the recruitment of less representative populations. © 2015 The Authors. Research Synthesis Methods published by John Wiley & Sons, Ltd. PMID:26333419

  14. In Order to Teach Me, You Have to Know Me: A Mixed-Methods Study of African-American Male Classroom Engagement

    ERIC Educational Resources Information Center

    Henderson, Jack L.

    2013-01-01

    Nationally, 30% of high school students do not graduate. Among this percentage, 50% are African-American. This study focused on at-promise African-American male classroom engagement where the researcher employed a mixed-methods methodology. Findings reveal that in order to engage and keep at-promise African-American males in high school, educators…

  15. Methods for evaluating cervical range of motion in trauma settings.

    PubMed

    Voss, Sarah; Page, Michael; Benger, Jonathan

    2012-08-02

    Immobilisation of the cervical spine is a common procedure following traumatic injury. This is often precautionary as the actual incidence of spinal injury is low. Nonetheless, stabilisation of the head and neck is an important part of pre-hospital care due to the catastrophic damage that may follow if further unrestricted movement occurs in the presence of an unstable spinal injury. Currently available collars are limited by the potential for inadequate immobilisation and complications caused by pressure on the patient's skin, restricted airway access and compression of the jugular vein. Alternative approaches to cervical spine immobilisation are being considered, and the investigation of these new methods requires a standardised approach to the evaluation of neck movement. This review summarises the research methods and scientific technology that have been used to assess and measure cervical range of motion, and which are likely to underpin future research in this field. A systematic search of international literature was conducted to evaluate the methodologies used to assess the extremes of movement that can be achieved in six domains. 34 papers were included in the review. These studies used a range of methodologies, but study quality was generally low. Laboratory investigations and biomechanical studies have gradually given way to methods that more accurately reflect the real-life situations in which cervical spine immobilisation occurs. Latterly, new approaches using virtual reality and simulation have been developed. Coupled with modern electromagnetic tracking technology this has considerable potential for effective application in future research. However, use of these technologies in real life settings can be problematic and more research is needed.

  16. Examining science achievement of African American females in suburban middle schools: A mixed methods study

    NASA Astrophysics Data System (ADS)

    Topping, Kecia C.

    This dissertation examined factors that affected the science achievement of African American females in suburban middle schools. The research literature informed that African American females are facing the barriers of race, gender, socioeconomic status, and cultural learning style preferences. Nationally used measurements of science achievement such as the Standardized Achievement Test, Tenth edition (SAT-10), National Assessment for Educational Progress, and National Center for Educational Statistics showed that African American females are continuing to falter in the areas of science when compared to other ethnic groups. This study used a transformative sequential explanatory mixed methods design. In the first, quantitative, phase, the relationships among the dependent variables, science subscale SAT-10 NCE scores, yearly averages, and the independent variables, attitude toward science scores obtained from the Modified Fennema-Sherman Attitudes toward Science Scale, socioeconomics, and caregiver status were tested. The participants were 150 African American females in grades 6 through 8 in four suburban middle schools located in the Southeastern United States. The results showed a positive, significant linear relationship between the females' attitude and their science subscale SAT-10 NCE scores and a positive, significant linear relationship between the females' attitudes and their yearly averages in science. The results also confirmed that attitude was a significant predictor of science subscale SAT-10 NCE scores for these females and that attitude and socioeconomics were significant predictors of the females' yearly averages in science. In the second, qualitative, phase, nine females purposefully selected from those who had high and low attitude towards science scores on the scale in the quantitative phase were interviewed. The themes that emerged revealed seven additional factors that impacted the females' science achievement. They were usefulness of science

  17. African American Organ Donor Registration: A Mixed Methods Design using the Theory of Planned Behavior

    PubMed Central

    DuBay, Derek A.; Ivankova, Nataliya; Herby, Ivan; Wynn, Theresa A.; Kohler, Connie; Berry, Beverly; Foushee, Herman; Carson, April; Redden, David T.; Holt, Cheryl; Siminoff, Laura; Fouad, Mona; Martin, Michelle Y.

    2015-01-01

    Context A large racial disparity exists in organ donation. Objective The purpose of this study was to identify factors associated with becoming a registered organ donor in among African Americans in Alabama. Methods The study utilized a concurrent mixed methods design guided by the Theory of Planned Behavior to analyze African American’s decisions to become a registered organ donor using both qualitative (focus groups) and quantitative (survey) methods. Results The sample consisted of 22 registered organ donors (ROD) and 65 non-registered participants (NRP) from six focus groups completed in urban (n=3) and rural (n=3) areas. Participants emphasized the importance of the autonomy to make one’s own organ donation decision and have this decision honored posthumously. One novel barrier to becoming a ROD was the perception that organs from African Americans were often unusable due to high prevalence of chronic medical conditions such as diabetes and hypertension. Another novel theme discussed as an advantage to becoming a ROD was the subsequent motivation to take responsibility for one’s health. Family and friends were the most common groups of persons identified as approving and disapproving of the decision to become a ROD. The most common facilitator to becoming a ROD was information, while fear and the lack of information were the most common barriers. In contrast, religious beliefs, mistrust and social justice themes were infrequently referenced as barriers to becoming a ROD. Discussion Findings from this study may be useful for prioritizing organ donation community-based educational interventions in campaigns to increase donor registration. PMID:25193729

  18. Profile Evolution Simulation in Etching Systems Using Level Set Methods

    NASA Technical Reports Server (NTRS)

    Hwang, Helen H.; Govindan, T. R.; Meyyappan, M.

    1998-01-01

    Semiconductor device profiles are determined by the characteristics of both etching and deposition processes. In particular, a highly anisotropic etch is required to achieve vertical sidewalls. However, etching is comprised of both anisotropic and isotropic components, due to ion and neutral fluxes, respectively. In Ar/Cl2 plasmas, for example, neutral chlorine reacts with the Si surfaces to form silicon chlorides. These compounds are then removed by the impinging ion fluxes. Hence the directionality of the ions (and thus the ion angular distribution function, or IAD), as well as the relative fluxes of neutrals and ions determines the amount of undercutting. One method of modeling device profile evolution is to simulate the moving solid-gas interface between the semiconductor and the plasma as a string of nodes. The velocity of each node is calculated and then the nodes are advanced accordingly. Although this technique appears to be relatively straightforward, extensive looping schemes are required at the profile corners. An alternate method is to use level set theory, which involves embedding the location of the interface in a field variable. The normal speed is calculated at each mesh point, and the field variable is updated. The profile comers are more accurately modeled as the need for looping algorithms is eliminated. The model we have developed is a 2-D Level Set Profile Evolution Simulation (LSPES). The LSPES calculates etch rates of a substrate in low pressure plasmas due to the incident ion and neutral fluxes. For a Si substrate in an Ar/C12 gas mixture, for example, the predictions of the LSPES are identical to those from a string evolution model for high neutral fluxes and two different ion angular distributions.(2) In the figure shown, the relative neutral to ion flux in the bulk plasma is 100 to 1. For a moderately isotropic ion angular distribution function as shown in the cases in the left hand column, both the LSPES (top row) and rude's string

  19. Local innovation for improving primary care cardiology in resource-limited African settings: an insight on the Cardio Pad® project in Cameroon

    PubMed Central

    Jingi, Ahmadou M.; Kengne, André Pascal

    2014-01-01

    Cardiovascular disease (CVD) is an emerging threat to the health of populations in Africa. With the inadequate health infrastructures, understaffed and underfunded health systems, African countries are ill-prepared to cope with the increasing demand for care for CVD, particularly for populations in remote and underserved rural areas, where 60% of the population currently reside. Task shifting and telehealth have been suggested as strategies to overcome the current health workforce shortage in African countries, and to increase access to prevention and curative services for emerging CVD. However, strategies for promoting their incorporation into the existing health systems, have yet to be developed. The Cardio Pad® initiative (originating from Cameroon) seeks to provide appropriate solutions to improve the application of telemedicine for CVD prevention and control in remote African settings. The Cardio Pad® is a tele-cardiology device which provides a number of advantages in terms of cost, ease of use, autonomy and reduced technology requirements. It is a fully touch screen medical device which enables cardiac tests such as electrocardiograms (ECG) to be performed in remote underserved areas (rural areas for instance), while the test results are transferred wirelessly via mobile phone connection, to specialist physicians who can interpret them and provide assistance with case management. While most of the current telemedicine clinical services on the African continent receive most expertise from developed countries, the Cardio Pad®, a local invention by a 26-year-old Cameroon-trained engineer demonstrates how much innovative solutions to combat CVD and other health issues could and should be developed locally in Africa. PMID:25414826

  20. Inferring the demographic history of African farmers and pygmy hunter-gatherers using a multilocus resequencing data set.

    PubMed

    Patin, Etienne; Laval, Guillaume; Barreiro, Luis B; Salas, Antonio; Semino, Ornella; Santachiara-Benerecetti, Silvana; Kidd, Kenneth K; Kidd, Judith R; Van der Veen, Lolke; Hombert, Jean-Marie; Gessain, Antoine; Froment, Alain; Bahuchet, Serge; Heyer, Evelyne; Quintana-Murci, Lluís

    2009-04-01

    The transition from hunting and gathering to farming involved a major cultural innovation that has spread rapidly over most of the globe in the last ten millennia. In sub-Saharan Africa, hunter-gatherers have begun to shift toward an agriculture-based lifestyle over the last 5,000 years. Only a few populations still base their mode of subsistence on hunting and gathering. The Pygmies are considered to be the largest group of mobile hunter-gatherers of Africa. They dwell in equatorial rainforests and are characterized by their short mean stature. However, little is known about the chronology of the demographic events-size changes, population splits, and gene flow--ultimately giving rise to contemporary Pygmy (Western and Eastern) groups and neighboring agricultural populations. We studied the branching history of Pygmy hunter-gatherers and agricultural populations from Africa and estimated separation times and gene flow between these populations. We resequenced 24 independent noncoding regions across the genome, corresponding to a total of approximately 33 kb per individual, in 236 samples from seven Pygmy and five agricultural populations dispersed over the African continent. We used simulation-based inference to identify the historical model best fitting our data. The model identified included the early divergence of the ancestors of Pygmy hunter-gatherers and farming populations approximately 60,000 years ago, followed by a split of the Pygmies' ancestors into the Western and Eastern Pygmy groups approximately 20,000 years ago. Our findings increase knowledge of the history of the peopling of the African continent in a region lacking archaeological data. An appreciation of the demographic and adaptive history of African populations with different modes of subsistence should improve our understanding of the influence of human lifestyles on genome diversity.

  1. Congruence of Standard Setting Methods for a Nursing Certification Examination.

    ERIC Educational Resources Information Center

    Fabrey, Lawrence J.; Raymond, Mark R.

    The American Nurses' Association certification provides professional recognition beyond licensure to nurses who pass an examination. To determine the passing score as it would be set by a representative peer group, a survey was mailed to a random sample of 200 recently certified nurses. Three questions were asked: (1) what percentage of examinees…

  2. Where is the faith? Using a CBPR approach to propose adaptations to an evidence-based HIV prevention intervention for adolescents in African American faith settings.

    PubMed

    Lightfoot, Alexandra F; Taggart, Tamara; Woods-Jaeger, Briana A; Riggins, Linda; Jackson, Melvin R; Eng, Eugenia

    2014-08-01

    African American adolescents are at increased risk for HIV/AIDS. Using a community-based participatory research approach, we engaged three black churches in adapting an evidence-based HIV prevention intervention, Focus on Youth (FOY)+ImPACT, for faith settings. To identify potential adaptations to increase FOY's relevance, utility, and efficacy for faith settings, we conducted eight focus groups pre- and post-intervention. Recommendations for maintaining FOY's core elements and enhancing its cultural authenticity include the following: incorporating faith tools, building pastor capacity, strengthening parent-child communication skills, and expanding social support for parents and youth. Engaging faith communities in adapting and implementing evidence-based HIV prevention programs could reduce HIV/AIDS disparities.

  3. Characterization of atherosclerosis by histochemical and immunohistochemical methods in African grey parrots (Psittacus erithacus) and Amazon parrots (Amazona spp.).

    PubMed

    Fricke, Cornelia; Schmidt, Volker; Cramer, Kerstin; Krautwald-Junghanns, Maria-Elisabeth; Dorrestein, Gerry M

    2009-09-01

    The aim of the study was to characterize atherosclerotic changes in African grey parrots (Psittacus erithacus) and Amazon parrots (Amazona spp.) by histochemical and immunohistochemical methods. Samples of the aorta ascendens and trunci brachiocephalici from 62 African grey parrots and 35 Amazon parrots were stained by hematoxylin and eosin and Elastica van Gieson for grading of atherosclerosis in these birds. Four different stages were differentiated. The incidence of atherosclerosis in the examined parrots was 91.9% in African grey parrots and 91.4% in Amazon parrots. To evaluate the pathogenesis in birds, immunohistochemical methods were performed to demonstrate lymphocytes, macrophages, smooth muscle cells, and chondroitin sulfate. According to the missing lymphocytes and macrophages and the absence of invasion and proliferation of smooth muscle cells in each atherosclerotic stage, "response-to-injury hypothesis" seems inapplicable in parrots. Additionally, we found alterations of vitally important organs (heart, lungs) significantly correlated with atherosclerosis of the aorta ascendens.

  4. Urban African American Parents’ Messages about Violence: A Mixed Methods Study

    PubMed Central

    Lindstrom Johnson, Sarah; Finigan, Nadine; Bradshaw, Catherine; Haynie, Denise; Cheng, Tina L.

    2015-01-01

    Family socialization, which includes parental control and support, plays an important role in reducing the likelihood of adolescent involvement in conflict. This study examined the strategies that urban parents living in neighborhoods with high crime rates suggest to help their adolescent children avoid or deescalate conflict. Data come from 48 African American parent/adolescent dyads recruited through the youths’ middle school. Dyads responded to three video-taped scenarios depicting youth in potential conflict situations. Qualitative methods were used to identify 11 strategies parents suggested to help youth avoid or deescalate conflict. Although the majority of parents advocated for non-violent solutions, these same parents described situations in which their child may need to use violence. These findings have important implications for family-focused violence prevention programs. PMID:26726283

  5. Extension and Enhancement Methods for Setting Data Quality Objectives

    SciTech Connect

    D. Goodman

    2000-03-01

    The project developed statistical tools for the application of decision theory and operations research methods, including cost-benefit analysis, to the DQO process for environmental clean up. A pilot study was conducted, using these methods at the Hanford site, to estimate vadose zone contamination plumes under the SX tank farm, and to help plan further sampling.

  6. Device and Method for Gathering Ensemble Data Sets

    NASA Technical Reports Server (NTRS)

    Racette, Paul E. (Inventor)

    2014-01-01

    An ensemble detector uses calibrated noise references to produce ensemble sets of data from which properties of non-stationary processes may be extracted. The ensemble detector comprising: a receiver; a switching device coupled to the receiver, the switching device configured to selectively connect each of a plurality of reference noise signals to the receiver; and a gain modulation circuit coupled to the receiver and configured to vary a gain of the receiver based on a forcing signal; whereby the switching device selectively connects each of the plurality of reference noise signals to the receiver to produce an output signal derived from the plurality of reference noise signals and the forcing signal.

  7. 48 CFR 19.502-4 - Methods of conducting set-asides.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Methods of conducting set... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 19.502-4 Methods of conducting set-asides. (a) Total small business set-asides may be conducted by using simplified acquisition...

  8. Fuzzy set methods for object recognition in space applications

    NASA Technical Reports Server (NTRS)

    Keller, James M.

    1991-01-01

    Progress on the following tasks is reported: (1) fuzzy set-based decision making methodologies; (2) feature calculation; (3) clustering for curve and surface fitting; and (4) acquisition of images. The general structure for networks based on fuzzy set connectives which are being used for information fusion and decision making in space applications is described. The structure and training techniques for such networks consisting of generalized means and gamma-operators are described. The use of other hybrid operators in multicriteria decision making is currently being examined. Numerous classical features on image regions such as gray level statistics, edge and curve primitives, texture measures from cooccurrance matrix, and size and shape parameters were implemented. Several fractal geometric features which may have a considerable impact on characterizing cluttered background, such as clouds, dense star patterns, or some planetary surfaces, were used. A new approach to a fuzzy C-shell algorithm is addressed. NASA personnel are in the process of acquiring suitable simulation data and hopefully videotaped actual shuttle imagery. Photographs have been digitized to use in the algorithms. Also, a model of the shuttle was assembled and a mechanism to orient this model in 3-D to digitize for experiments on pose estimation is being constructed.

  9. Survey of South African fruit juices using a fast screening HILIC-MS method.

    PubMed

    Stander, Marietjie A; Kühn, Wernich; Hiten, Nicholas F

    2013-01-01

    Adulteration of fruit juices--by the addition of sugar or other less expensive fruit juices as well as preservatives, artificial sweeteners and colours--was tested for by using a developed screening method. The method employs hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) using electrospray ionisation in the negative mode and ultraviolet light detection. Different fruit juices can be differentiated by the content of marker compounds like sorbitol, certain phenolic molecules and their saccharide profile. This method was used to test 46 fruit juice samples from the retail market as well as 12 control samples. The study focused on the main types of fruit juices consumed on the South African market including apple, orange, grape and blends of these juices with other fruits like mango, pear and guava. Overall, the 46 samples tested mostly agreed with label claims. One grape juice sample was adulterated, probably with apple juice. Natamycin above the legal limits was found in two samples. In addition, two samples contained natamycin and one sample benzoate without it being indicated on the label. The method is well suited as a quick screening method for fruit juice adulteration and if used routinely would reduce fruit juice adulteration without the cost of the current array of tests needed for authenticity testing.

  10. Trust in healthcare settings: Scale development, methods, and preliminary determinants

    PubMed Central

    LoCurto, Jamie; Berg, Gina M

    2016-01-01

    The literature contains research regarding how trust is formed in healthcare settings but rarely discusses trust formation in an emergent care population. A literature review was conducted to determine which of the trust determinants are important for this process as well as how to develop a scale to measure trust. A search generated a total of 155 articles, 65 of which met eligibility criteria. Determinants that were important included the following: honesty, confidentiality, dependability, communication, competency, fiduciary responsibility, fidelity, and agency. The process of developing a scale includes the following: a literature review, qualitative analysis, piloting, and survey validation. Results suggest that physician behaviors are important in influencing trust in patients and should be included in scales measuring trust. Next steps consist of interviewing emergent care patients to commence the process of developing a scale. PMID:27635245

  11. Trust in healthcare settings: Scale development, methods, and preliminary determinants

    PubMed Central

    LoCurto, Jamie; Berg, Gina M

    2016-01-01

    The literature contains research regarding how trust is formed in healthcare settings but rarely discusses trust formation in an emergent care population. A literature review was conducted to determine which of the trust determinants are important for this process as well as how to develop a scale to measure trust. A search generated a total of 155 articles, 65 of which met eligibility criteria. Determinants that were important included the following: honesty, confidentiality, dependability, communication, competency, fiduciary responsibility, fidelity, and agency. The process of developing a scale includes the following: a literature review, qualitative analysis, piloting, and survey validation. Results suggest that physician behaviors are important in influencing trust in patients and should be included in scales measuring trust. Next steps consist of interviewing emergent care patients to commence the process of developing a scale.

  12. Methods and circuitry for reconfigurable SEU/SET tolerance

    NASA Technical Reports Server (NTRS)

    Shuler, Jr., Robert L. (Inventor)

    2010-01-01

    A device is disclosed in one embodiment that has multiple identical sets of programmable functional elements, programmable routing resources, and majority voters that correct errors. The voters accept a mode input for a redundancy mode and a split mode. In the redundancy mode, the programmable functional elements are identical and are programmed identically so the voters produce an output corresponding to the majority of inputs that agree. In a split mode, each voter selects a particular programmable functional element output as the output of the voter. Therefore, in the split mode, the programmable functional elements can perform different functions, operate independently, and/or be connected together to process different parts of the same problem.

  13. Trust in healthcare settings: Scale development, methods, and preliminary determinants.

    PubMed

    LoCurto, Jamie; Berg, Gina M

    2016-01-01

    The literature contains research regarding how trust is formed in healthcare settings but rarely discusses trust formation in an emergent care population. A literature review was conducted to determine which of the trust determinants are important for this process as well as how to develop a scale to measure trust. A search generated a total of 155 articles, 65 of which met eligibility criteria. Determinants that were important included the following: honesty, confidentiality, dependability, communication, competency, fiduciary responsibility, fidelity, and agency. The process of developing a scale includes the following: a literature review, qualitative analysis, piloting, and survey validation. Results suggest that physician behaviors are important in influencing trust in patients and should be included in scales measuring trust. Next steps consist of interviewing emergent care patients to commence the process of developing a scale. PMID:27635245

  14. A Mixed Methods Study: African American Students' Performance Trends and Perceptions Towards Advanced Placement Literature Courses and Examinations

    ERIC Educational Resources Information Center

    Buford, Brandie J.

    2012-01-01

    The purpose of this mixed methods study was to describe the perceptions of African American students pertaining to their engagement in Advanced Placement English Literature and Composition course and Advanced Placement English Literature and Composition examination. A purposive sampling design was employed to select 12 participants from one urban…

  15. Sex-Role Egalitarian Attitudes and Gender Role Socialization Experiences of African American Men and Women: A Mixed Methods Paradigm

    ERIC Educational Resources Information Center

    Heard, Courtney Christian Charisse

    2013-01-01

    The purpose of this study was to assess the sex-role egalitarian attitudes and gender role socialization experiences of African American men and women. A sequential mixed-methods design was employed to research this phenomenon. The Sex-Role Egalitarianism Scale-Short Form BB (SRES-BB) was utilized to assess sex-role egalitarian attitudes (King…

  16. Hanford Site groundwater monitoring: Setting, sources and methods

    SciTech Connect

    M.J. Hartman

    2000-04-11

    Groundwater monitoring is conducted on the Hanford Site to meet the requirements of the Resource Conservation and Recovery Act of 1976 (RCRA); Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA); U.S. Department of Energy (DOE) orders; and the Washington Administrative Code. Results of monitoring are published annually (e.g., PNNL-11989). To reduce the redundancy of these annual reports, background information that does not change significantly from year to year has been extracted from the annual report and published in this companion volume. This report includes a description of groundwater monitoring requirements, site hydrogeology, and waste sites that have affected groundwater quality or that require groundwater monitoring. Monitoring networks and methods for sampling, analysis, and interpretation are summarized. Vadose zone monitoring methods and statistical methods also are described. Whenever necessary, updates to information contained in this document will be published in future groundwater annual reports.

  17. Fuzzy set methods for object recognition in space applications

    NASA Technical Reports Server (NTRS)

    Keller, James M.

    1992-01-01

    Progress on the following tasks is reported: feature calculation; membership calculation; clustering methods (including initial experiments on pose estimation); and acquisition of images (including camera calibration information for digitization of model). The report consists of 'stand alone' sections, describing the activities in each task. We would like to highlight the fact that during this quarter, we believe that we have made a major breakthrough in the area of fuzzy clustering. We have discovered a method to remove the probabilistic constraints that the sum of the memberships across all classes must add up to 1 (as in the fuzzy c-means). A paper, describing this approach, is included.

  18. Thriving, Managing, and Struggling: A Mixed Methods Study of Adolescent African Refugees’ Psychosocial Adjustment

    PubMed Central

    Weine, Stevan Merrill; Ware, Norma; Tugenberg, Toni; Hakizimana, Leonce; Dahnweih, Gonwo; Currie, Madeleine; Wagner, Maureen; Levin, Elise

    2013-01-01

    Objectives The purpose of this mixed method study was to characterize the patterns of psychosocial adjustment among adolescent African refugees in U.S. resettlement. Methods A purposive sample of 73 recently resettled refugee adolescents from Burundi and Liberia were followed for two years and qualitative and quantitative data was analyzed using a mixed methods exploratory design. Results Protective resources identified were the family and community capacities that can promote youth psychosocial adjustment through: 1) Finances for necessities; 2) English proficiency; 3) Social support networks; 4) Engaged parenting; 5) Family cohesion; 6) Cultural adherence and guidance; 7) Educational support; and, 8) Faith and religious involvement. The researchers first inductively identified 19 thriving, 29 managing, and 25 struggling youths based on review of cases. Univariate analyses then indicated significant associations with country of origin, parental education, and parental employment. Multiple regressions indicated that better psychosocial adjustment was associated with Liberians and living with both parents. Logistic regressions showed that thriving was associated with Liberians and higher parental education, managing with more parental education, and struggling with Burundians and living parents. Qualitative analysis identified how these factors were proxy indicators for protective resources in families and communities. Conclusion These three trajectories of psychosocial adjustment and six domains of protective resources could assist in developing targeted prevention programs and policies for refugee youth. Further rigorous longitudinal mixed-methods study of adolescent refugees in U.S. resettlement are needed. PMID:24205467

  19. Planning the Social Studies Programme for the Contemporary African Society.

    ERIC Educational Resources Information Center

    Enaohwo, J. Okpako

    1989-01-01

    Identifies characteristics of a viable social studies program for African nations, urging multidisciplinary and integrated approaches. Offers a cyclical framework for planning a curriculum which includes defining the problem, setting objectives, identifying methods of implementation, evaluation, and regeneration. (LS)

  20. Methods and Applications for Visualization of SNOMED CT Concept Sets

    PubMed Central

    Højen, A.R.; Sundvall, E.; Gøeg, K.R.

    2014-01-01

    Summary Inconsistent use of SNOMED CT concepts may reduce comparability of information in health information systems. Terminology implementation should be approached by common strategies for navigating and selecting proper concepts. This study aims to explore ways of illustrating common pathways and ancestors of particular sets of concepts, to support consistent use of SNOMED CT and also assess potential applications for such visualizations. The open source prototype presented is an interactive web-based re-implementation of the terminology visualization tool TermViz that provides an overview of concepts and their hierarchical relations. It provides terminological features such as interactively rearranging graphs, fetching more concept nodes, highlighting least common parents and shared pathways in merged graphs etc. Four teams of three to four people used the prototype to complete a terminology mapping task and then, in focus group interviews, discussed the user experience and potential future tool usage. Potential purposes discussed included SNOMED CT search and training, consistent selection of concepts and content management. The evaluation indicated that the tool may be useful in many contexts especially if integrated with existing systems, and that the graph layout needs further tuning and development. PMID:24734129

  1. Understanding the Role of Athletics and Resiliency in the Persistence and Success of African American Males in a Community College Setting

    ERIC Educational Resources Information Center

    James, Melinda Lloyd

    2013-01-01

    This dissertation examined the part athletics and resiliency played in degree completion of African American males. Specifically, it investigated three at-risk African American males and the dynamics of athletic participation and resiliency in their degree completion. In view of the fact that many African American students begin their higher…

  2. A Monte Carlo Investigation of the Contrasting Groups Standard Setting Method.

    ERIC Educational Resources Information Center

    Cizek, Gregory J.; Husband, Timothy H.

    The contrasting groups method is one of many possible methods for setting passing scores. The most commonly used method is probably that developed by W. H. Angoff (1971), but it has been suggested that the Angoff method may not be appropriate for many standard setting applications in education. The contrasting groups method is explored as an…

  3. NVG adjustment methods, eyepiece focus settings, and vision

    NASA Astrophysics Data System (ADS)

    Van Arsdel, Richard; Baldwin, J. Bruce; Hausmann, Martha A.; Harrington, Lawrence K.; Craig, Jeffrey L.; Koepke, Corbin G.

    2006-05-01

    Several studies and many anecdotal reports indicate that aircrew members focus night vision goggle (NVG) eyepiece lenses to more negative powers than would be expected based on refractive error, presumably due to instrument myopia, "dark focus" myopia, and other factors. Excessive negative power stimulates accommodation, introducing risks from discomfort, fatigue, and blurred vision. Aircrew members are trained to employ specific adjustment techniques to minimize "over-minusing" of eyepiece lens powers, but those techniques are prone to error. The currently fielded AN/AVS-9 NVG (F4949) has a focus range of (+2.0) to (-6.0) diopters, and meets the needs of most aircrew. However, the new AN/AVS-10 NVG panoramic night vision goggle (PNVG) has a fixed focus of (-1.0) diopters due to engineering design constraints. Accessory snap-on lenses are available, but data are needed to optimize the distribution of lens powers to be acquired and maintained. This study involved the characterization of vision (visual acuity, perceived quality, and comfort) as a function of: 1) eyepiece focus setting using trial lenses; 2) F4949 eyepiece focus adjustments using a point source vs. a Hoffman 20/20 box; and 3) PNVG eyepiece lens selections using a lens bar vs. snap-on lens selections. Eight subjects with normal (20/20 corrected) vision ranging in age from 23 years to 49 participated in this study. The experiments were conducted in the Aerospace Vision Experimental Laboratory and the Dynamic Vision Assessment Facility at Wright Patterson AFB, Ohio using F4949 and PNVG devices with a custom-designed NVG-compatible computer-based visual acuity acquisition system.

  4. Evaluating COSMO's lake module (FLake) for an East-African lake using a comprehensive set of lake temperature profiles

    NASA Astrophysics Data System (ADS)

    Thiery, W.; Martynov, A.; Darchambeau, F.; Demuzere, M.; van Lipzig, N.

    2012-04-01

    The African great lakes are of utmost importance for the local economy (fishing), as well as being essential to the survival of the local people. During last decades, these lakes have been changing rapidly and their evolution is a major concern. Hence, it is important to correctly represent them in regional climate models for simulations over tropical Africa. However, so far lake models have been developed and tested primarily for boreal conditions. In this study, for the first time the freshwater lake model FLake is evaluated over East-Africa, more specifically over lake Kivu. Meteorological observations from January 2003 to December 2008 from an automatic weather station in Bukavu, DRC, are used to drive the standalone version of FLake. For the evaluation, a unique dataset is used which contains over 200 temperature profiles recorded since 2002. Results show that FLake in its default configuration is very successful at reproducing both the timing and magnitude of the seasonal cycle at 5 m depth. Flake captures that this seasonality is regulated by the water vapour pressure, which constrains evaporation except during summer (JJA). A positive bias of ~1 K is attributed to the driving data, which are collected in the city and are therefore expected to mirror higher temperatures and lower wind speeds compared to the lake surface. The evaluation also showed that driving FLake with Era-Interim from the nearest pixel does only slightly deteriorate the model performance. Using forcing fields from the Canadian Regional Climate Model, version 5 (CRCM5) simulation output gives similar performance as Era-Interim. Furthermore, a drawback of FLake is that it does not account for salinity and its effect upon lake stratification, and therefore requires artificial initial conditions for both lake depth and bottom temperature in order to reproduce the correct mixing regime in lake Kivu. Further research will therefore aim at improving FLake's representation of tropical lakes.

  5. Exploring the genetic architecture of alcohol dependence in African-Americans via analysis of a genomewide set of common variants.

    PubMed

    Yang, Can; Li, Cong; Kranzler, Henry R; Farrer, Lindsay A; Zhao, Hongyu; Gelernter, Joel

    2014-05-01

    Alcohol dependence (AD) is a complex psychiatric disorder that affects about 12.5 % of US adults. Genetic factors play a major role in the development of AD. We conducted a genomewide association study in 2,875 African-Americans including 1,719 AD cases and 1,156 controls. We used the Illumina Omni 1-Quad microarray, which yielded 769,498 single-nucleotide polymorphisms (SNPs) after quality control. To explore the genetic architecture of AD, we estimated the variance that could be explained by all SNPs and subsets of SNPs using two different approaches to genome partitioning. We found that 23.9 % (s.e. 9.3 %) of the phenotypic variance could be explained by using all of the common SNPs on the array. We also found a significant linear relationship between the proportion of the top SNPs used and the phenotypic variance explained by them. Based on genome partitioning of common variants, we also observed a significant linear relationship between the variance explained by a chromosome and its length. Chromosome 4, known to contain several AD risk genes, accounted for excess risk in proportion to its length. By functional partitioning, we found that the genetic variants within 20 kb of genes explained 17.5 % (s.e. 11.4 %) of the phenotypic variance. Our findings are consistent with the generally accepted view that AD is a highly polygenic trait, i.e., the genetic risk in AD appears to be conferred by multiple variants, each of which may have a small or moderate effect.

  6. Biostatistical concepts and methods in the legal setting.

    PubMed

    Gastwirth, J L; Greenhouse, S W

    1995-08-15

    Biostatistical concepts and methods apply to various problems arising in actual U.S. legal cases. These involve: measures of association, assessing the potential effect of omitted variables and the Peters-Belson approach to regression. In particular, we present the inapplicability of Fisher's exact test in the case where the process determining the marginal sample sizes is not independent of the hypothesis under study by the 2 x 2 table. We adapt Cornfield's procedure to assess whether the omission of another factor could have contributed to a non-significant finding of the effect of the major factor under investigation. Finally, we demonstrate the relevance and utility of the Peters-Belson regression methodology to equal pay and promotion cases.

  7. Neighborhood × Serotonin Transporter Linked Polymorphic Region (5-HTTLPR) interactions for substance use from ages 10 to 24 years using a harmonized data set of African American children.

    PubMed

    Windle, Michael; Kogan, Steven M; Lee, Sunbok; Chen, Yi-Fu; Lei, Karlo Mankit; Brody, Gene H; Beach, Steven R H; Yu, Tianyi

    2016-05-01

    This study investigated the influences of neighborhood factors (residential stability and neighborhood disadvantage) and variants of the serotonin transporter linked polymorphic region (5-HTTLPR) genotype on the development of substance use among African American children aged 10-24 years. To accomplish this, a harmonized data set of five longitudinal studies was created via pooling overlapping age cohorts to establish a database with 2,689 children and 12,474 data points to span ages 10-24 years. A description of steps used in the development of the harmonized data set is provided, including how issues such as the measurement equivalence of constructs were addressed. A sequence of multilevel models was specified to evaluate Gene × Environment effects on growth of substance use across time. Findings indicated that residential instability was associated with higher levels and a steeper gradient of growth in substance use across time. The inclusion of the 5-HTTLPR genotype provided greater precision to the relationships in that higher residential instability, in conjunction with the risk variant of 5-HTTLPR (i.e., the short allele), was associated with the highest level and steepest gradient of growth in substance use across ages 10-24 years. The findings demonstrated how the creation of a harmonized data set increased statistical power to test Gene × Environment interactions for an under studied sample.

  8. The giant Pan-African Hook Batholith, Central Zambia: A-type magmatism in a syn-collisional setting

    NASA Astrophysics Data System (ADS)

    Milani, Lorenzo; Lehmann, Jérémie; Naydenov, Kalin V.; Saalmann, Kerstin; Kinnaird, Judith A.; Daly, J. Stephen; Frei, Dirk; Lobo-Guerrero Sanz, Alberto

    2015-04-01

    The Pan-African Hook Batholith formed during the assembly of the Gondwana supercontinent between 570 and 520 Ma (U-Pb on zircon) as a result of syn-collisional stage interaction between the Congo and Kalahari Cratons1. The extension of the batholith, exposed and undercover, is estimated to be between 25,000 and 30,000 km2. The bimodal magmatism (mafic to predominantly felsic) is characterized by both an alkali-calcic and an alkalic suite, with the felsic rocks featuring a typical A-type, metaluminous, high Fe/Mg and K/Na geochemical signature. The scattered outcrops of gabbroic rocks, both tholeiitic and alkaline, suggest periodic input of mantle material, which, in some cases, interacted with metasomatizing fluids. Fractional crystallization is invoked for the most differentiated products, while Sr-Nd isotopes rule out any significant contribution from crustal assimilation. Exceptionally highly radiogenic Pb isotopes have been measured on both unaltered and hydrothermally altered rocks, and attest to the radiogenic character of the batholith. The Pb isotopes indicate that the anomalous signature was acquired during, or soon after, magma emplacement, and was likely enhanced by metasomatizing fluids. An enrichment in Th and U, affecting large portions of the crust along the southern margin of the Congo Craton, is suggested by comparable anomalous Pb isotopes measured in basement gneisses in the Domes Region, Zambian Copperbelt. Geochemical and isotopic evidence support interaction between mantle components and portions of the deep crust at pressures of < 10 kbar, while decompression melting of rising asthenospheric mantle ponding at the base of the crust heated, and ultimately melted, crustal material. Low-pressure mineral phases in metasedimentary wall rocks along the eastern margin of the pluton indicate that the magma was subsequently emplaced at shallow crustal depths. A crucial contribution to the crustal melting was likely provided by internal radiogenic heat

  9. Comparing Yes/No Angoff and Bookmark Standard Setting Methods in the Context of English Assessment

    ERIC Educational Resources Information Center

    Hsieh, Mingchuan

    2013-01-01

    The Yes/No Angoff and Bookmark method for setting standards on educational assessment are currently two of the most popular standard-setting methods. However, there is no research into the comparability of these two methods in the context of language assessment. This study compared results from the Yes/No Angoff and Bookmark methods as applied to…

  10. Mission to Mars set to revolutionise ESA's working methods

    NASA Astrophysics Data System (ADS)

    1999-03-01

    ESA took the decision in principle to send a mission to Mars shortly after the loss of the Russian spacecraft Mars '96 with several European experiments on board. The Agency wanted to build on the Mars '96 payload experience to design a mission that would put Europe at the leading-edge of Mars exploration. But ESA had to act quickly. Major space missions can take up to 11 years from concept to launch - and there was little more than six years to go before the positioning of the planets in 2003 would offer the shortest travel time to Mars with the highest payload. Budgetary pressures were also forcing ESA to look for cheaper ways of building spacecraft. A Mars mission therefore seemed a good candidate to explore cheaper and faster working methods. Mars Express (so called because of the streamlined development time) is the first of a new type of "flexible" missions in ESA's long-term scientific programme, which should be built and launched for about half the previous budget for similar missions. The global budget for Mars Express will actually be only150 million Euro including spacecraft development, launch by a Russian Soyuz/Fregat launcher, operations, testing and management costs. Costs are being saved by shortening the time from original concept to launch, re-using existing hardware, adopting new project management practices, and having access to reduced launcher costs. Selection of the scientific payload by ESA's scientific advisory bodies and mission definition by industry have been performed simultaneously, instead of sequentially as in previous missions. This has cut the time from concept to the awarding of today's design and development contract from about five years to little more than one year. The design and development phase will take under four years, compared with up to six previously. Mars Express is making maximum use of pre-existing technology, which is either "off-the-shelf" or has already been developed for the Rosetta mission (also due for launch

  11. Eina! Ouch! Eish! Professionals' Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC.

    PubMed

    Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

    2015-01-01

    Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children's continued participation in school. In this study, South African school professionals' perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children's pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study. PMID:26372118

  12. Eina! Ouch! Eish! Professionals' Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC.

    PubMed

    Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

    2015-01-01

    Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children's continued participation in school. In this study, South African school professionals' perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children's pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study.

  13. Eina! Ouch! Eish! Professionals’ Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC

    PubMed Central

    Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

    2015-01-01

    Abstract Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children’s continued participation in school. In this study, South African school professionals’ perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children’s pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study. PMID:26372118

  14. Using community-based participatory mixed methods research to understand preconception health in African American communities of Arizona.

    PubMed

    Hussaini, Khaleel S; Hamm, Eric; Means, Toni

    2013-12-01

    The article discusses Arizona's strategic implementation and evaluation of the first time motherhood initiative grant (FTMI) to understand preconception health among African American men and women in Arizona. Longitudinal focus groups assessed whether African American men and women in the targeted areas comprehended and recalled the messages related to preconception health. Matched pre and posttests assessed community members' knowledge of preconception as well as physicians' perceptions on preconception health and care. Focus-group data were transcribed and coded by independent coders to conduct content analyses. Inter-rater reliability and agreement among coders, bivariate and multivariate statistics were conducted for quantitative matched pre and posttests data using SAS v9.2 (SAS Institute, Cary, NC). The social marketing campaign had limited impact in recall and comprehension of the preconception health message among African American men and women. Data from focus groups revealed that African American men and women perceived preconception health to be vital. And results from the pretest and posttests of community-based presentations, further supported this finding. Evidence from Grand Round presentations indicated that practitioners and health care providers had diverging views on preconception health. Use of community-based participatory mixed methods research can facilitate better understanding of the efficacy of strategic interventions such as FTMI and can provide valuable information on preconception health. Cost limitations often prohibit extensive evaluation of social marketing campaigns, hence, evaluators and researchers should assess the feasibility of conducting an efficacy study versus an effectiveness study in evaluating social marketing campaigns.

  15. Women's views on consent, counseling and confidentiality in PMTCT: a mixed-methods study in four African countries

    PubMed Central

    2012-01-01

    Background Ambitious UN goals to reduce the mother-to-child transmission of HIV have not been met in much of Sub-Saharan Africa. This paper focuses on the quality of information provision and counseling and disclosure patterns in Burkina Faso, Kenya, Malawi and Uganda to identify how services can be improved to enable better PMTCT outcomes. Methods Our mixed-methods study draws on data obtained through: (1) the MATCH (Multi-country African Testing and Counseling for HIV) study's main survey, conducted in 2008-09 among clients (N = 408) and providers at health facilities offering HIV Testing and Counseling (HTC) services; 2) semi-structured interviews with a sub-set of 63 HIV-positive women on their experiences of stigma, disclosure, post-test counseling and access to follow-up psycho-social support; (3) in-depth interviews with key informants and PMTCT healthcare workers; and (4) document study of national PMTCT policies and guidelines. We quantitatively examined differences in the quality of counseling by country and by HIV status using Fisher's exact tests. Results The majority of pregnant women attending antenatal care (80-90%) report that they were explained the meaning of the tests, explained how HIV can be transmitted, given advice on prevention, encouraged to refer their partners for testing, and given time to ask questions. Our qualitative findings reveal that some women found testing regimes to be coercive, while disclosure remains highly problematic. 79% of HIV-positive pregnant women reported that they generally keep their status secret; only 37% had disclosed to their husband. Conclusion To achieve better PMTCT outcomes, the strategy of testing women in antenatal care (perceived as an exclusively female domain) when they are already pregnant needs to be rethought. When scaling up HIV testing programs, it is particularly important that issues of partner disclosure are taken seriously. PMID:22236097

  16. Decentralization of CD4 testing in resource-limited settings: 7 years of experience in six African countries.

    PubMed

    Marinucci, F; Medina-Moreno, S; Paterniti, A D; Wattleworth, M; Redfield, R R

    2011-05-01

    Improving access to CD4 testing in resource-limited settings can be achieved through both centralized and decentralized testing networks. Decentralized testing models are more suitable for countries where the HIV epidemic affects a large portion of rural populations. Timely access to accurate CD4 results is crucial at the primary level of the health system. For the past 7 years, the Institute of Human Virology of the University of Maryland School of Medicine has implemented a flexible and sustainable three-phase model: (1) site assessment and improvement, (2) appropriate technology selection with capacity building through practical training and laboratory mentoring, and (3) quality management system strengthening and monitoring, to support accessibility to reliable CD4 counting at the point of service. CD4 testing capacity was established in 122 of 229 (53%) laboratories supported in Nigeria, Uganda, Kenya, Zambia, Tanzania, and Rwanda. Among those in rural settings, 46% (69/151) had CD4 testing available at site level, with a functioning flow cytometer installed at 28% (8/29) and 50% (61/122) of level 1 and level 2 sites, respectively. To strengthen local capacity, a total of 1,152 laboratory technicians were trained through 188 training sessions provided both on-site and at central locations. The overall quality of CD4 total testing procedure was assessed at 76% (92/121) of the laboratories, with 25% (23/92), 34% (31/92), and 33% (30/92) of them reporting excellent, good, and satisfactory performance. Balancing country-specific factors with the location of the clinic, number of patients, and the expected workload, was crucial in adapting this flexible model for decentralizing CD4 testing. The close collaboration with local governments and private vendors was key to successfully expanding access to CD4 testing within the framework of HIV care and treatment programs and for the sustainability of medical laboratories in resource-limited settings. PMID:21495181

  17. Best practices in developing a national palliative care policy in resource limited settings: lessons from five African countries.

    PubMed

    Luyirika, Emmanuel Bk; Namisango, Eve; Garanganga, Eunice; Monjane, Lidia; Ginindza, Ntombi; Madonsela, Gugulethu; Kiyange, Fatia

    2016-01-01

    Given the high unmet need for palliative care in Africa and other resource limited settings, it is important that countries embrace the public health approach to increasing access through its integration within existing healthcare systems. To give this approach a strong foundation that would ensure sustainability, the World Health Organisation urges member states to ensure that policy environments are suitable for this intervention. The development, strengthening, and implementation of national palliative care policies is a priority. Given the lack of a critical mass of palliative care professionals in the region and deficiency in documenting and sharing best practices as part of information critical for regional development, policy development becomes a complex process. This article shares experiences with regard to best practices when advocating the national palliative care policies. It also tells about policy development process, the important considerations, and cites examples of policy content outlines in Africa. PMID:27563347

  18. Best practices in developing a national palliative care policy in resource limited settings: lessons from five African countries.

    PubMed

    Luyirika, Emmanuel Bk; Namisango, Eve; Garanganga, Eunice; Monjane, Lidia; Ginindza, Ntombi; Madonsela, Gugulethu; Kiyange, Fatia

    2016-01-01

    Given the high unmet need for palliative care in Africa and other resource limited settings, it is important that countries embrace the public health approach to increasing access through its integration within existing healthcare systems. To give this approach a strong foundation that would ensure sustainability, the World Health Organisation urges member states to ensure that policy environments are suitable for this intervention. The development, strengthening, and implementation of national palliative care policies is a priority. Given the lack of a critical mass of palliative care professionals in the region and deficiency in documenting and sharing best practices as part of information critical for regional development, policy development becomes a complex process. This article shares experiences with regard to best practices when advocating the national palliative care policies. It also tells about policy development process, the important considerations, and cites examples of policy content outlines in Africa.

  19. Best practices in developing a national palliative care policy in resource limited settings: lessons from five African countries

    PubMed Central

    Luyirika, Emmanuel BK; Namisango, Eve; Garanganga, Eunice; Monjane, Lidia; Ginindza, Ntombi; Madonsela, Gugulethu; Kiyange, Fatia

    2016-01-01

    Given the high unmet need for palliative care in Africa and other resource limited settings, it is important that countries embrace the public health approach to increasing access through its integration within existing healthcare systems. To give this approach a strong foundation that would ensure sustainability, the World Health Organisation urges member states to ensure that policy environments are suitable for this intervention. The development, strengthening, and implementation of national palliative care policies is a priority. Given the lack of a critical mass of palliative care professionals in the region and deficiency in documenting and sharing best practices as part of information critical for regional development, policy development becomes a complex process. This article shares experiences with regard to best practices when advocating the national palliative care policies. It also tells about policy development process, the important considerations, and cites examples of policy content outlines in Africa. PMID:27563347

  20. An efficient graph theory based method to identify every minimal reaction set in a metabolic network

    PubMed Central

    2014-01-01

    Background Development of cells with minimal metabolic functionality is gaining importance due to their efficiency in producing chemicals and fuels. Existing computational methods to identify minimal reaction sets in metabolic networks are computationally expensive. Further, they identify only one of the several possible minimal reaction sets. Results In this paper, we propose an efficient graph theory based recursive optimization approach to identify all minimal reaction sets. Graph theoretical insights offer systematic methods to not only reduce the number of variables in math programming and increase its computational efficiency, but also provide efficient ways to find multiple optimal solutions. The efficacy of the proposed approach is demonstrated using case studies from Escherichia coli and Saccharomyces cerevisiae. In case study 1, the proposed method identified three minimal reaction sets each containing 38 reactions in Escherichia coli central metabolic network with 77 reactions. Analysis of these three minimal reaction sets revealed that one of them is more suitable for developing minimal metabolism cell compared to other two due to practically achievable internal flux distribution. In case study 2, the proposed method identified 256 minimal reaction sets from the Saccharomyces cerevisiae genome scale metabolic network with 620 reactions. The proposed method required only 4.5 hours to identify all the 256 minimal reaction sets and has shown a significant reduction (approximately 80%) in the solution time when compared to the existing methods for finding minimal reaction set. Conclusions Identification of all minimal reactions sets in metabolic networks is essential since different minimal reaction sets have different properties that effect the bioprocess development. The proposed method correctly identified all minimal reaction sets in a both the case studies. The proposed method is computationally efficient compared to other methods for finding minimal

  1. Minimum incidence of adult invasive pneumococcal disease in Blantyre, Malawi an urban african setting: a hospital based prospective cohort study.

    PubMed

    Bar-Zeev, Naor; Mtunthama, Neema; Gordon, Stephen B; Mwafulirwa, Gershom; French, Neil

    2015-01-01

    Invasive pneumococcal disease causes substantial morbidity and mortality in Africa. Evaluating population level indirect impact on adult disease of pneumococcal conjugate vaccine (PCV) programmes in infants requires baseline population incidence rates but these are often lacking in areas with limited disease surveillance. We used hospital based blood culture and cerebrospinal fluid surveillance to calculate minimal incidence of invasive pneumococcal disease in the adult (≥15 years old) population of Blantyre, a rapidly growing urban centre in southern Malawi, in the period preceding vaccine introduction. Invasive pneumococcal disease incidence in Blantyre district was high, mean 58.1 (95% confidence interval (CI): 53.7, 62.7) per 100,000 person years and peaking among 35 to 40 year olds at 108.8 (95%CI: 89.0, 131.7) mirroring the population age prevalence of HIV infection. For pneumococcal bacteraemia in urban Blantyre, mean incidence was 60.6 (95% CI: 55.2, 66.5) per 100,000 person years, peaking among 35 to 40 year olds at 114.8 (95%CI: 90.3, 143.9). We suspected that our surveillance may under-ascertain the true burden of disease, so we used location data from bacteraemic subjects and projected population estimates to calculate local sub-district incidence, then examined the impact of community level socio-demographic covariates as possible predictors of local sub-district incidence of pneumococcal and non-pneumococcal pathogenic bacteraemia. Geographic heterogeneity in incidence was marked with localised hotspots but ward level covariates apart from prison were not associated with pneumococcal bacteraemia incidence. Modelling suggests that the current sentinel surveillance system under-ascertains the true burden of disease. We outline a number of challenges to surveillance for pneumococcal disease in our low-resource setting. Subsequent surveillance in the vaccine era will have to account for geographic heterogeneity when evaluating population level indirect

  2. Minimum Incidence of Adult Invasive Pneumococcal Disease in Blantyre, Malawi an Urban African Setting: A Hospital Based Prospective Cohort Study

    PubMed Central

    Bar-Zeev, Naor; Mtunthama, Neema; Gordon, Stephen B; Mwafulirwa, Gershom; French, Neil

    2015-01-01

    Invasive pneumococcal disease causes substantial morbidity and mortality in Africa. Evaluating population level indirect impact on adult disease of pneumococcal conjugate vaccine (PCV) programmes in infants requires baseline population incidence rates but these are often lacking in areas with limited disease surveillance. We used hospital based blood culture and cerebrospinal fluid surveillance to calculate minimal incidence of invasive pneumococcal disease in the adult (≥15 years old) population of Blantyre, a rapidly growing urban centre in southern Malawi, in the period preceding vaccine introduction. Invasive pneumococcal disease incidence in Blantyre district was high, mean 58.1 (95% confidence interval (CI): 53.7, 62.7) per 100,000 person years and peaking among 35 to 40 year olds at 108.8 (95%CI: 89.0, 131.7) mirroring the population age prevalence of HIV infection. For pneumococcal bacteraemia in urban Blantyre, mean incidence was 60.6 (95% CI: 55.2, 66.5) per 100,000 person years, peaking among 35 to 40 year olds at 114.8 (95%CI: 90.3, 143.9). We suspected that our surveillance may under-ascertain the true burden of disease, so we used location data from bacteraemic subjects and projected population estimates to calculate local sub-district incidence, then examined the impact of community level socio-demographic covariates as possible predictors of local sub-district incidence of pneumococcal and non-pneumococcal pathogenic bacteraemia. Geographic heterogeneity in incidence was marked with localised hotspots but ward level covariates apart from prison were not associated with pneumococcal bacteraemia incidence. Modelling suggests that the current sentinel surveillance system under-ascertains the true burden of disease. We outline a number of challenges to surveillance for pneumococcal disease in our low-resource setting. Subsequent surveillance in the vaccine era will have to account for geographic heterogeneity when evaluating population level indirect

  3. How to combine correlated data sets-A Bayesian hyperparameter matrix method

    NASA Astrophysics Data System (ADS)

    Ma, Y.-Z.; Berndsen, A.

    2014-07-01

    We construct a “hyperparameter matrix” statistical method for performing the joint analyses of multiple correlated astronomical data sets, in which the weights of data sets are determined by their own statistical properties. This method is a generalization of the hyperparameter method constructed by Lahav et al. (2000) and Hobson et al. (2002) which was designed to combine independent data sets. The advantage of our method is to treat correlations between multiple data sets and gives appropriate relevant weights of multiple data sets with mutual correlations. We define a new “element-wise” product, which greatly simplifies the likelihood function with hyperparameter matrix. We rigorously prove the simplified formula of the joint likelihood and show that it recovers the original hyperparameter method in the limit of no covariance between data sets. We then illustrate the method by applying it to a demonstrative toy model of fitting a straight line to two sets of data. We show that the hyperparameter matrix method can detect unaccounted systematic errors or underestimated errors in the data sets. Additionally, the ratio of Bayes' factors provides a distinct indicator of the necessity of including hyperparameters. Our example shows that the likelihood we construct for joint analyses of correlated data sets can be widely applied to many astrophysical systems.

  4. Incarceration history relative to health, substance use, and violence in a sample of vulnerable South African women: implications for health services in criminal justice settings

    PubMed Central

    Johnson, Jennifer E; Carney, Tara; Kline, Tracy; Browne, Felicia A; Wechsberg, Wendee M

    2012-01-01

    International research has suggested that women in the criminal justice system carry a higher burden of many illnesses than women in the community, especially mental health disorders, substance use disorders, sexually transmitted infections, and a history of violent victimization. Knowledge of these health disparities is often used to advocate for relevant screening and treatment services for women passing through criminal justice custody within US and European settings. However, almost all criminal justice health research has taken place in high-income countries, with little or no research taking place in other countries, especially in South Africa. This baseline analysis compares the health, substance use, and violent victimization of women who have ever been incarcerated to those who have not, in a cross-sectional sample of 720 young, vulnerable, substance-using women in Cape Town, South Africa. Results of univariate tests indicated that women who had ever been incarcerated had worse health, mental health, and sexually transmitted infection indicators and were more likely to report use of substances and to have been victims of physical and sexual assault than women who had never been incarcerated. Passing through the criminal justice system appears to be a marker for a variety of current and/or future health service needs among vulnerable South African women, suggesting that screening, prevention, and treatment referral efforts at the time of intersection with the criminal justice system may reduce health burden for these women. PMID:24474876

  5. Prevalence and Predictors of Intestinal Helminth Infections Among Human Immunodeficiency Virus Type 1–Infected Adults in an Urban African Setting

    PubMed Central

    Modjarrad, Kayvon; Zulu, Isaac; Redden, David T.; Njobvu, Lungowe; Freedman, David O.; Vermund, Sten H.

    2009-01-01

    Sub-Saharan Africa is disproportionately burdened by intestinal helminth and human immunodeficiency virus (HIV)-1 infection. Recent evidence suggests detrimental immunologic effects from concomitant infection with the two pathogens. Few studies, however, have assessed the prevalence of and predictors for intestinal helminth infection among HIV-1–infected adults in urban African settings where HIV infection rates are highest. We collected and analyzed sociodemographic and parasitologic data from 297 HIV-1–infected adults (mean age = 31.1 years, 69% female) living in Lusaka, Zambia to assess the prevalence and associated predictors of helminth infection. We found at least one type of intestinal helminth in 24.9% of HIV-infected adults. Thirty-nine (52.7%) were infected with Ascaris lumbricoides, and 29 (39.2%) were infected with hookworm. More than 80% were light-intensity infections. A recent visit to a rural area, food shortage, and prior history of helminth infection were significant predictors of current helminth status. The high helminth prevalence and potential for adverse interactions between helminths and HIV suggests that helminth diagnosis and treatment should be part of routine HIV care. PMID:16222025

  6. Determination of sotolon content in South African white wines by two novel HPLC-UV and UPLC-MS methods.

    PubMed

    Gabrielli, Mario; Buica, Astrid; Fracassetti, Daniela; Stander, Marietjie; Tirelli, Antonio; du Toit, Wessel J

    2015-02-15

    Sotolon has been reported to play an important role in the atypical ageing and aroma character of many wines. A number of analytical techniques for sotolon analysis in wine have been reported, but these often require extensive sample preparation. In this work we report a HPLC-UV method and a novel UPLC-MS method to determine sotolon concentrations in white wines with little sample preparation applied for the first time for the evaluation of sotolon levels in South African wines. The validation showed that the instrumental methods had good accuracy, repeatability and linearity, but the UPLC-MS method proved more sensitive. For both methods, quantification limits were lower than the sotolon odour threshold in wine (10μg/L), 0.86μg/L and 0.013μg/L, for HPLC-UV and UPLC-MS methods, respectively. Sotolon levels in 65 South African white wines were often found to be lower than the reported odour threshold, with the highest concentration being 9.11μg/L. However, for low levels (<1μg/L), unknown interferences in certain wines led to sotolon not being quantified with the HPLC-UV method, which made the UPLC-MS method more suitable.

  7. Referential learning of French and Czech labels in African grey parrots (Psittacus erithacus): different methods yield contrasting results.

    PubMed

    Giret, Nicolas; Péron, Franck; Lindová, Jitka; Tichotová, Lenka; Nagle, Laurent; Kreutzer, Michel; Tymr, Frantisek; Bovet, Dalila

    2010-10-01

    Some African grey parrots (Psittacus erithacus), the most famous being Pepperberg's parrot Alex, are able to imitate human speech and produce labels referentially. In this study, the aim was to teach ten African grey parrots from two laboratories to label items. Training three parrots from the first laboratory for several months with the Model/Rival method, developed by Pepperberg, in which two humans interact in front of the subject to demonstrate the use of a label, led to disappointing results. Similarly, seven parrots from the second laboratory, having been trained with several variants of Model/Rival attained little success. After the informal observation of the efficiency of other methods (i.e. learning to imitate labels either spontaneously or with specific learning methods and use of these labels referentially), four different teaching methods were tested with two birds: the Model/Rival; Repetition/Association which consisted of repeating a label and presenting the item only when the parrot produced the label; Intuitive in which the experimenter handled an item and repeated its name in front of the subject; Diffusion in which labels with either variable or flat intonation were played back daily to parrots. One bird learned three labels, one of which was used referentially, with the Repetition/Association method. He learned one label non-referentially with the Model/Rival but no labels were acquired using the other methods. The second bird did not learn any labels. This study demonstrates that different methods can be efficient to teach labels referentially and it suggests that rearing conditions and interindividual variability are important features when assessing learning ability of African grey parrots.

  8. A Mixed-Method Analysis of African-American Women's Attendance at an HIV Prevention Intervention

    ERIC Educational Resources Information Center

    Pinto, R. M.; McKay, M. M.

    2006-01-01

    Grounded in a model of service utilization, this study conceptualizes attendance of African-American women at an HIV prevention intervention as associated with influences across three ecological domains--individual, service (program), and social network. First, the texts of responses to semistructured, open-ended elicitation interviews were…

  9. Resisting Dominant Discourses: Implications of Indigenous, African Feminist Theory and Methods for Gender and Education Research

    ERIC Educational Resources Information Center

    Chilisa, Bagele; Ntseane, Gabo

    2010-01-01

    In this paper we explore tensions between Western gender theory and research, and post-colonial and indigenous feminist standpoints, which challenge us to re-define our roles as feminist-activist educators and researchers working with formerly colonised and historically marginalised communities. We discuss how African and Black feminist approaches…

  10. A Researcher "Called" to "Taboo" Places?: A Burgeoning Research Method in African-Centered Education

    ERIC Educational Resources Information Center

    Shockley, Kmt G.

    2009-01-01

    This article presents a self-reflexive analysis of the complexities of conducting Afrocentric education research while living with a "double consciousness." Having been "called" to places that are considered to be "taboo" the author takes readers on a journey that begins in his busy mind and ends in on the African continent in a "rabbit hole."…

  11. Comparison of Enrollment Rates of African-American Families Into a School-Based Tobacco Prevention Trial Using Two Recruitment Strategies in Urban and Rural Settings

    PubMed Central

    Tingen, Martha S.; Andrews, Jeannette O.; Heath, Janie; Turnmire, Ashley E.; Waller, Jennifer L.; Treiber, Frank A.

    2013-01-01

    Purpose This study evaluated similarities and differences of enrollment rates using two different recruitment strategies for a tobacco control trial in rural and urban African-American (AA) elementary school families. Design A comparative study, nested within a larger randomized controlled trial, was used to test the effectiveness of two recruitment approaches on enrollment rates in rural and urban AA families. Setting The study was conducted in 14 Title 1 elementary schools in the southeastern United States: 7 rural and 7 urban. Subjects There were 736 eligible AA families, and 332 (45%) completed informed consent and were enrolled into the study. Intervention The Facilitate, Open and transparent communication, Shared benefits, Team and tailored, Educate bilaterally, and Relationships, realistic and rewards (FOSTER) approach guided the two recruitment strategies: (1) written informational packets provided to fourth graders to take home to parents; and (2) proactive, face-to-face family information sessions held at schools. Measures Enrollment rates were based on responsiveness to the two recruitment strategies and completion of the informed consent process. Analysis Chi-square, Cochran-Mantel-Haenszel, and Breslow-Day tests were performed. Results Higher enrollment rates occurred during the family session for both rural and urban families (100% rural, 93.6% urban; p= .0475) than informational packets alone (28.7’% rural, 22% urban; p < .0001). Rural family enrollment rates were overall higher than urban rates regardless of recruitment strategy (52.0% rural vs. 39.6% urban; p= .0008). Conclusion The findings suggest the FOSTER approach, although effective in both rural and urban settings, was more successful in recruiting rural families. PMID:23448420

  12. The reliability and validity of the comfort level method of setting hearing aid gain.

    PubMed

    Walden, B E; Schuchman, G I; Sedge, R K

    1977-11-01

    The comfort level method (Carhart, 1946) probably is the most widely used procedure for setting the acoustic gain of hearing aids. A series of experiments were conducted to determine the test-retest reliability of the comfort level method and the relationship between the comfort settings established in a clinical test suite and the comfort settings utilized in more realistic daily listening situations. Adults with bilateral sensorineural hearing impairments were subjects. The results suggest that the comfort level method has good test-retest reliability for most clinical purposes. Further, clinically established comfort settings may accurately represent typical daily-use settings if the input level used to establish the comfort settings in the clinical environment is 70 dB SPL.

  13. Using Resampling To Estimate the Precision of an Empirical Standard-Setting Method.

    ERIC Educational Resources Information Center

    Muijtjens, Arno M. M.; Kramer, Anneke W. M.; Kaufman, David M.; Van der Vleuten, Cees P. M.

    2003-01-01

    Developed a method to estimate the cutscore precisions for empirical standard-setting methods by using resampling. Illustrated the method with two actual datasets consisting of 86 Dutch medical residents and 155 Canadian medical students taking objective structured clinical examinations. Results show the applicability of the method. (SLD)

  14. Benchmarking Data Sets for the Evaluation of Virtual Ligand Screening Methods: Review and Perspectives.

    PubMed

    Lagarde, Nathalie; Zagury, Jean-François; Montes, Matthieu

    2015-07-27

    Virtual screening methods are commonly used nowadays in drug discovery processes. However, to ensure their reliability, they have to be carefully evaluated. The evaluation of these methods is often realized in a retrospective way, notably by studying the enrichment of benchmarking data sets. To this purpose, numerous benchmarking data sets were developed over the years, and the resulting improvements led to the availability of high quality benchmarking data sets. However, some points still have to be considered in the selection of the active compounds, decoys, and protein structures to obtain optimal benchmarking data sets.

  15. A Model for the Roll-Out of Comprehensive Adult Male Circumcision Services in African Low-Income Settings of High HIV Incidence: The ANRS 12126 Bophelo Pele Project

    PubMed Central

    Lissouba, Pascale; Taljaard, Dirk; Rech, Dino; Doyle, Sean; Shabangu, Daniel; Nhlapo, Cynthia; Otchere-Darko, Josephine; Mashigo, Thabo; Matson, Caitlin; Lewis, David; Billy, Scott; Auvert, Bertran

    2010-01-01

    Background World Health Organization (WHO)/Joint United Nations Programme on AIDS (UNAIDS) has recommended adult male circumcision (AMC) for the prevention of heterosexually acquired HIV infection in men from communities where HIV is hyperendemic and AMC prevalence is low. The objective of this study was to investigate the feasibility of the roll-out of medicalized AMC according to UNAIDS/WHO operational guidelines in a targeted African setting. Methods and Findings The ANRS 12126 “Bophelo Pele” project was implemented in 2008 in the township of Orange Farm (South Africa). It became functional in 5 mo once local and ethical authorizations were obtained. Project activities involved community mobilization and outreach, as well as communication approaches aimed at both men and women incorporating broader HIV prevention strategies and promoting sexual health. Free medicalized AMC was offered to male residents aged 15 y and over at the project's main center, which had been designed for low-income settings. Through the establishment of an innovative surgical organization, up to 150 AMCs under local anesthesia, with sterilized circumcision disposable kits and electrocautery, could be performed per day by three task-sharing teams of one medical circumciser and five nurses. Community support for the project was high. As of November 2009, 14,011 men had been circumcised, averaging 740 per month in the past 12 mo, and 27.5% of project participants agreed to be tested for HIV. The rate of adverse events, none of which resulted in permanent damage or death, was 1.8%. Most of the men surveyed (92%) rated the services provided positively. An estimated 39.1% of adult uncircumcised male residents have undergone surgery and uptake is steadily increasing. Conclusion This study demonstrates that a quality AMC roll-out adapted to African low-income settings is feasible and can be implemented quickly and safely according to international guidelines. The project can be a model for

  16. Preventing cognitive decline in older African Americans with mild cognitive impairment: design and methods of a randomized clinical trial.

    PubMed

    Rovner, Barry W; Casten, Robin J; Hegel, Mark T; Leiby, Benjamin E

    2012-07-01

    Mild Cognitive Impairment (MCI) affects 25% of older African Americans and predicts progression to Alzheimer's disease. An extensive epidemiologic literature suggests that cognitive, physical, and/or social activities may prevent cognitive decline. We describe the methods of a randomized clinical trial to test the efficacy of Behavior Activation to prevent cognitive decline in older African Americans with the amnestic multiple domain subtype of MCI. Community Health Workers deliver 6 initial in-home treatment sessions over 2-3 months and then 6 subsequent in-home booster sessions using language, materials, and concepts that are culturally relevant to older African Americans during this 24 month clinical trial. We are randomizing 200 subjects who are recruited from churches, senior centers, and medical clinics to Behavior Activation or Supportive Therapy, which controls for attention. The primary outcome is episodic memory as measured by the Hopkins Verbal Learning Test-Revised at baseline and at months 3, 12, 18, and 24. The secondary outcomes are general and domain-specific neuropsychological function, activities of daily living, depression, and quality-of-life. The negative results of recent clinical trials of drug treatments for MCI and Alzheimer's disease suggest that behavioral interventions may provide an alternative treatment approach to preserve cognition in an aging society.

  17. Preventing cognitive decline in older African Americans with mild cognitive impairment: design and methods of a randomized clinical trial.

    PubMed

    Rovner, Barry W; Casten, Robin J; Hegel, Mark T; Leiby, Benjamin E

    2012-07-01

    Mild Cognitive Impairment (MCI) affects 25% of older African Americans and predicts progression to Alzheimer's disease. An extensive epidemiologic literature suggests that cognitive, physical, and/or social activities may prevent cognitive decline. We describe the methods of a randomized clinical trial to test the efficacy of Behavior Activation to prevent cognitive decline in older African Americans with the amnestic multiple domain subtype of MCI. Community Health Workers deliver 6 initial in-home treatment sessions over 2-3 months and then 6 subsequent in-home booster sessions using language, materials, and concepts that are culturally relevant to older African Americans during this 24 month clinical trial. We are randomizing 200 subjects who are recruited from churches, senior centers, and medical clinics to Behavior Activation or Supportive Therapy, which controls for attention. The primary outcome is episodic memory as measured by the Hopkins Verbal Learning Test-Revised at baseline and at months 3, 12, 18, and 24. The secondary outcomes are general and domain-specific neuropsychological function, activities of daily living, depression, and quality-of-life. The negative results of recent clinical trials of drug treatments for MCI and Alzheimer's disease suggest that behavioral interventions may provide an alternative treatment approach to preserve cognition in an aging society. PMID:22406101

  18. The Gabor-Based Tensor Level Set Method for Multiregional Image Segmentation

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Gao, Xinbo; Tao, Dacheng; Li, Xuelong; Li, Jie

    This paper represents a new level set method for multiregional image segmentation. It employs the Gabor filter bank to extract local geometrical features and builds the pixel tensor representation whose dimensionality is reduced by using the offline tensor analysis. Then multiphase level set functions are evolved in the tensor field to detect the boundaries of the corresponding image. The proposed method has three main advantages as follows. Firstly, employing the Gabor filter bank, the model is more robust against the salt-and-pepper noise. Secondly, the pixel tensor representation comprehensively depicts the information of pixels, which results in a better performance on the non-homogenous image segmentation. Thirdly, the model provides a uniform equation for multiphase level set functions to make it more practical. We apply the proposed method to synthetic and medical images respectively, and the results indicate that the proposed method is superior to the typical region-based level set method.

  19. Level set discrete element method for three-dimensional computations with triaxial case study

    NASA Astrophysics Data System (ADS)

    Kawamoto, Reid; Andò, Edward; Viggiani, Gioacchino; Andrade, José E.

    2016-06-01

    In this paper, we outline the level set discrete element method (LS-DEM) which is a discrete element method variant able to simulate systems of particles with arbitrary shape using level set functions as a geometric basis. This unique formulation allows seamless interfacing with level set-based characterization methods as well as computational ease in contact calculations. We then apply LS-DEM to simulate two virtual triaxial specimens generated from XRCT images of experiments and demonstrate LS-DEM's ability to quantitatively capture and predict stress-strain and volume-strain behavior observed in the experiments.

  20. A Critical Analysis of the Body of Work Method for Setting Cut-Scores

    ERIC Educational Resources Information Center

    Radwan, Nizam; Rogers, W. Todd

    2006-01-01

    The recent increase in the use of constructed-response items in educational assessment and the dissatisfaction with the nature of the decision that the judges must make using traditional standard-setting methods created a need to develop new and effective standard-setting procedures for tests that include both multiple-choice and…

  1. Dynamics of parabolic equations via the finite element method I. Continuity of the set of equilibria

    NASA Astrophysics Data System (ADS)

    Figueroa-López, R. N.; Lozada-Cruz, G.

    2016-11-01

    In this paper we study the dynamics of parabolic semilinear differential equations with homogeneous Dirichlet boundary conditions via the discretization of finite element method. We provide an appropriate functional setting to treat this problem and, as a first step, we show the continuity of the set of equilibria and of its linear unstable manifolds.

  2. The Reliability and Validity of the Comfort Level Method of Setting Hearing Aid Gain

    ERIC Educational Resources Information Center

    Walden, Brian E.; And Others

    1977-01-01

    Investigated in a series of experiments with 40 adults (20- to 70-years-old) having bilateral sensorineural hearing impairments was the test-retest reliability of the comfort level method for setting the acoustic gain of hearing aids, and the relationship between the comfort settings utilized in more realistic daily listening situations.…

  3. Combining the Best of Two Standard Setting Methods: The Ordered Item Booklet Angoff

    ERIC Educational Resources Information Center

    Smith, Russell W.; Davis-Becker, Susan L.; O'Leary, Lisa S.

    2014-01-01

    This article describes a hybrid standard setting method that combines characteristics of the Angoff (1971) and Bookmark (Mitzel, Lewis, Patz & Green, 2001) methods. The proposed approach utilizes strengths of each method while addressing weaknesses. An ordered item booklet, with items sorted based on item difficulty, is used in combination…

  4. A Body of Work Standard-Setting Method with Construct Maps

    ERIC Educational Resources Information Center

    Wyse, Adam E.; Bunch, Michael B.; Deville, Craig; Viger, Steven G.

    2014-01-01

    This article describes a novel variation of the Body of Work method that uses construct maps to overcome problems of transparency, rater inconsistency, and scores gaps commonly occurring with the Body of Work method. The Body of Work method with construct maps was implemented to set cut-scores for two separate K-12 assessment programs in a large…

  5. A New Method for Setting Calculation Sequence of Directional Relay Protection in Multi-Loop Networks

    NASA Astrophysics Data System (ADS)

    Haijun, Xiong; Qi, Zhang

    2016-08-01

    Workload of relay protection setting calculation in multi-loop networks may be reduced effectively by optimization setting calculation sequences. A new method of setting calculation sequences of directional distance relay protection in multi-loop networks based on minimum broken nodes cost vector (MBNCV) was proposed to solve the problem experienced in current methods. Existing methods based on minimum breakpoint set (MBPS) lead to more break edges when untying the loops in dependent relationships of relays leading to possibly more iterative calculation workloads in setting calculations. A model driven approach based on behavior trees (BT) was presented to improve adaptability of similar problems. After extending the BT model by adding real-time system characters, timed BT was derived and the dependency relationship in multi-loop networks was then modeled. The model was translated into communication sequence process (CSP) models and an optimization setting calculation sequence in multi-loop networks was finally calculated by tools. A 5-nodes multi-loop network was applied as an example to demonstrate effectiveness of the modeling and calculation method. Several examples were then calculated with results indicating the method effectively reduces the number of forced broken edges for protection setting calculation in multi-loop networks.

  6. A Nonparametric, Multiple Imputation-Based Method for the Retrospective Integration of Data Sets.

    PubMed

    Carrig, Madeline M; Manrique-Vallier, Daniel; Ranby, Krista W; Reiter, Jerome P; Hoyle, Rick H

    2015-01-01

    Complex research questions often cannot be addressed adequately with a single data set. One sensible alternative to the high cost and effort associated with the creation of large new data sets is to combine existing data sets containing variables related to the constructs of interest. The goal of the present research was to develop a flexible, broadly applicable approach to the integration of disparate data sets that is based on nonparametric multiple imputation and the collection of data from a convenient, de novo calibration sample. We demonstrate proof of concept for the approach by integrating three existing data sets containing items related to the extent of problematic alcohol use and associations with deviant peers. We discuss both necessary conditions for the approach to work well and potential strengths and weaknesses of the method compared to other data set integration approaches.

  7. Benchmarking methods and data sets for ligand enrichment assessment in virtual screening.

    PubMed

    Xia, Jie; Tilahun, Ermias Lemma; Reid, Terry-Elinor; Zhang, Liangren; Wang, Xiang Simon

    2015-01-01

    Retrospective small-scale virtual screening (VS) based on benchmarking data sets has been widely used to estimate ligand enrichments of VS approaches in the prospective (i.e. real-world) efforts. However, the intrinsic differences of benchmarking sets to the real screening chemical libraries can cause biased assessment. Herein, we summarize the history of benchmarking methods as well as data sets and highlight three main types of biases found in benchmarking sets, i.e. "analogue bias", "artificial enrichment" and "false negative". In addition, we introduce our recent algorithm to build maximum-unbiased benchmarking sets applicable to both ligand-based and structure-based VS approaches, and its implementations to three important human histone deacetylases (HDACs) isoforms, i.e. HDAC1, HDAC6 and HDAC8. The leave-one-out cross-validation (LOO CV) demonstrates that the benchmarking sets built by our algorithm are maximum-unbiased as measured by property matching, ROC curves and AUCs.

  8. Evaluation of the Applicability of Different Age Determination Methods for Estimating Age of the Endangered African Wild Dog (Lycaon Pictus)

    PubMed Central

    Steenkamp, Gerhard; Groom, Rosemary J.

    2016-01-01

    African wild dogs (Lycaon pictus) are endangered and their population continues to decline throughout their range. Given their conservation status, more research focused on their population dynamics, population growth and age specific mortality is needed and this requires reliable estimates of age and age of mortality. Various age determination methods from teeth and skull measurements have been applied in numerous studies and it is fundamental to test the validity of these methods and their applicability to different species. In this study we assessed the accuracy of estimating chronological age and age class of African wild dogs, from dental age measured by (i) counting cementum annuli (ii) pulp cavity/tooth width ratio, (iii) tooth wear (measured by tooth crown height) (iv) tooth wear (measured by tooth crown width/crown height ratio) (v) tooth weight and (vi) skull measurements (length, width and height). A sample of 29 African wild dog skulls, from opportunistically located carcasses was analysed. Linear and ordinal regression analysis was done to investigate the performance of each of the six age determination methods in predicting wild dog chronological age and age class. Counting cementum annuli was the most accurate method for estimating chronological age of wild dogs with a 79% predictive capacity, while pulp cavity/tooth width ratio was also a reliable method with a 68% predictive capacity. Counting cementum annuli and pulp cavity/tooth width ratio were again the most accurate methods for separating wild dogs into three age classes (6–24 months; 25–60 months and > 60 months), with a McFadden’s Pseudo-R2 of 0.705 and 0.412 respectively. The use of the cementum annuli method is recommended when estimating age of wild dogs since it is the most reliable method. However, its use is limited as it requires tooth extraction and shipping, is time consuming and expensive, and is not applicable to living individuals. Pulp cavity/tooth width ratio is a

  9. African Refugee Parents' Involvement in Their Children's Schools: Barriers and Recommendations for Improvement

    ERIC Educational Resources Information Center

    Githembe, Purity Kanini

    2009-01-01

    The purpose of this study was to examine involvement of African refugee parents in the education of their elementary school children. The setting of the study was Northern and Southern Texas. African refugee parents and their children's teachers completed written surveys and also participated in interviews. In the study's mixed-method design,…

  10. Type-2 fuzzy set extension of DEMATEL method combined with perceptual computing for decision making

    NASA Astrophysics Data System (ADS)

    Hosseini, Mitra Bokaei; Tarokh, Mohammad Jafar

    2013-05-01

    Most decision making methods used to evaluate a system or demonstrate the weak and strength points are based on fuzzy sets and evaluate the criteria with words that are modeled with fuzzy sets. The ambiguity and vagueness of the words and different perceptions of a word are not considered in these methods. For this reason, the decision making methods that consider the perceptions of decision makers are desirable. Perceptual computing is a subjective judgment method that considers that words mean different things to different people. This method models words with interval type-2 fuzzy sets that consider the uncertainty of the words. Also, there are interrelations and dependency between the decision making criteria in the real world; therefore, using decision making methods that cannot consider these relations is not feasible in some situations. The Decision-Making Trail and Evaluation Laboratory (DEMATEL) method considers the interrelations between decision making criteria. The current study used the combination of DEMATEL and perceptual computing in order to improve the decision making methods. For this reason, the fuzzy DEMATEL method was extended into type-2 fuzzy sets in order to obtain the weights of dependent criteria based on the words. The application of the proposed method is presented for knowledge management evaluation criteria.

  11. A comparison of gene set analysis methods in terms of sensitivity, prioritization and specificity.

    PubMed

    Tarca, Adi L; Bhatti, Gaurav; Romero, Roberto

    2013-01-01

    Identification of functional sets of genes associated with conditions of interest from omics data was first reported in 1999, and since, a plethora of enrichment methods were published for systematic analysis of gene sets collections including Gene Ontology and biological pathways. Despite their widespread usage in reducing the complexity of omics experiment results, their performance is poorly understood. Leveraging the existence of disease specific gene sets in KEGG and Metacore® databases, we compared the performance of sixteen methods under relaxed assumptions while using 42 real datasets (over 1,400 samples). Most of the methods ranked high the gene sets designed for specific diseases whenever samples from affected individuals were compared against controls via microarrays. The top methods for gene set prioritization were different from the top ones in terms of sensitivity, and four of the sixteen methods had large false positives rates assessed by permuting the phenotype of the samples. The best overall methods among those that generated reasonably low false positive rates, when permuting phenotypes, were PLAGE, GLOBALTEST, and PADOG. The best method in the category that generated higher than expected false positives was MRGSE.

  12. An accurate conservative level set/ghost fluid method for simulating turbulent atomization

    SciTech Connect

    Desjardins, Olivier Moureau, Vincent; Pitsch, Heinz

    2008-09-10

    This paper presents a novel methodology for simulating incompressible two-phase flows by combining an improved version of the conservative level set technique introduced in [E. Olsson, G. Kreiss, A conservative level set method for two phase flow, J. Comput. Phys. 210 (2005) 225-246] with a ghost fluid approach. By employing a hyperbolic tangent level set function that is transported and re-initialized using fully conservative numerical schemes, mass conservation issues that are known to affect level set methods are greatly reduced. In order to improve the accuracy of the conservative level set method, high order numerical schemes are used. The overall robustness of the numerical approach is increased by computing the interface normals from a signed distance function reconstructed from the hyperbolic tangent level set by a fast marching method. The convergence of the curvature calculation is ensured by using a least squares reconstruction. The ghost fluid technique provides a way of handling the interfacial forces and large density jumps associated with two-phase flows with good accuracy, while avoiding artificial spreading of the interface. Since the proposed approach relies on partial differential equations, its implementation is straightforward in all coordinate systems, and it benefits from high parallel efficiency. The robustness and efficiency of the approach is further improved by using implicit schemes for the interface transport and re-initialization equations, as well as for the momentum solver. The performance of the method is assessed through both classical level set transport tests and simple two-phase flow examples including topology changes. It is then applied to simulate turbulent atomization of a liquid Diesel jet at Re=3000. The conservation errors associated with the accurate conservative level set technique are shown to remain small even for this complex case.

  13. Methods of artificial enlargement of the training set for statistical shape models.

    PubMed

    Koikkalainen, Juha; Tölli, Tuomas; Lauerma, Kirsi; Antila, Kari; Mattila, Elina; Lilja, Mikko; Lötjönen, Jyrki

    2008-11-01

    Due to the small size of training sets, statistical shape models often over-constrain the deformation in medical image segmentation. Hence, artificial enlargement of the training set has been proposed as a solution for the problem to increase the flexibility of the models. In this paper, different methods were evaluated to artificially enlarge a training set. Furthermore, the objectives were to study the effects of the size of the training set, to estimate the optimal number of deformation modes, to study the effects of different error sources, and to compare different deformation methods. The study was performed for a cardiac shape model consisting of ventricles, atria, and epicardium, and built from magnetic resonance (MR) volume images of 25 subjects. Both shape modeling and image segmentation accuracies were studied. The objectives were reached by utilizing different training sets and datasets, and two deformation methods. The evaluation proved that artificial enlargement of the training set improves both the modeling and segmentation accuracy. All but one enlargement techniques gave statistically significantly (p < 0.05) better segmentation results than the standard method without enlargement. The two best enlargement techniques were the nonrigid movement technique and the technique that combines principal component analysis (PCA) and finite element model (FEM). The optimal number of deformation modes was found to be near 100 modes in our application. The active shape model segmentation gave better segmentation accuracy than the one based on the simulated annealing optimization of the model weights.

  14. Projection Onto Convex Sets (POCS) method for photoacoustic tomography with a non negative constraint.

    PubMed

    Salehin, S M Akramus; Huang, Shaochun; Abhayapala, Thushara D

    2013-01-01

    Photoacoustic imaging is a biomedical imaging modality capable of early cancer detection. In this paper, we proposed a novel iterative Projections Onto Convex Sets (POCS) method for improving photoacoustic reconstruction. This method aims to obtain a non negative pressure distribution satisfying the measured signals. This POCS method is performed in the Fourier Bessel space avoiding matrix inversions in the projections, speeding up projections and is capable of handling the large data sets present in photoacoustic imaging. The numerical experiments performed showed that improved reconstruction was obtained with a few iterations together with the recovery of some lost information.

  15. Processor and method for developing a set of admissible fixture designs for a workpiece

    DOEpatents

    Brost, Randolph C.; Goldberg, Kenneth Y.; Canny, John; Wallack, Aaron S.

    1999-01-01

    Methods and apparatus are provided for developing a complete set of all admissible Type I and Type II fixture designs for a workpiece. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vise is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs.

  16. Processor and method for developing a set of admissible fixture designs for a workpiece

    DOEpatents

    Brost, Randolph C.; Goldberg, Kenneth Y.; Wallack, Aaron S.; Canny, John

    1996-01-01

    A fixture process and method is provided for developing a complete set of all admissible fixture designs for a workpiece which prevents the workpiece from translating or rotating. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vice is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs.

  17. Processor and method for developing a set of admissible fixture designs for a workpiece

    DOEpatents

    Brost, R.C.; Goldberg, K.Y.; Canny, J.; Wallack, A.S.

    1999-01-05

    Methods and apparatus are provided for developing a complete set of all admissible Type 1 and Type 2 fixture designs for a workpiece. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vise is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs. 44 figs.

  18. Processor and method for developing a set of admissible fixture designs for a workpiece

    DOEpatents

    Brost, R.C.; Goldberg, K.Y.; Wallack, A.S.; Canny, J.

    1996-08-13

    A fixture process and method is provided for developing a complete set of all admissible fixture designs for a workpiece which prevents the workpiece from translating or rotating. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vice is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs. 27 figs.

  19. Theory and methods for accuracy assessment of thematic maps using fuzzy sets

    SciTech Connect

    Gopal, S.; Woodcock, C. )

    1994-02-01

    The use of fuzzy sets in map accuracy assessment expands the amount of information that can be provided regarding the nature, frequency, magnitude, and source of errors in a thematic map. The need for using fuzzy sets arises from the observation that all map locations do not fit unambiguously in a single map category. Fuzzy sets allow for varying levels of set membership for multiple map categories. A linguistic measurement scale allows the kinds of comments commonly made during map evaluations to be used to quantify map accuracy. Four tables result from the use of fuzzy functions, and when taken together they provide more information than traditional confusion matrices. The use of a hypothetical dataset helps illustrate the benefits of the new methods. It is hoped that the enhanced ability to evaluate maps resulting from the use of fuzzy sets will improve our understanding of uncertainty in maps and facilitate improved error modeling. 40 refs.

  20. Automatic segmentation of Leishmania parasite in microscopic images using a modified CV level set method

    NASA Astrophysics Data System (ADS)

    Farahi, Maria; Rabbani, Hossein; Talebi, Ardeshir; Sarrafzadeh, Omid; Ensafi, Shahab

    2015-12-01

    Visceral Leishmaniasis is a parasitic disease that affects liver, spleen and bone marrow. According to World Health Organization report, definitive diagnosis is possible just by direct observation of the Leishman body in the microscopic image taken from bone marrow samples. We utilize morphological and CV level set method to segment Leishman bodies in digital color microscopic images captured from bone marrow samples. Linear contrast stretching method is used for image enhancement and morphological method is applied to determine the parasite regions and wipe up unwanted objects. Modified global and local CV level set methods are proposed for segmentation and a shape based stopping factor is used to hasten the algorithm. Manual segmentation is considered as ground truth to evaluate the proposed method. This method is tested on 28 samples and achieved 10.90% mean of segmentation error for global model and 9.76% for local model.

  1. A combined watershed and level set method for segmentation of brightfield cell images

    NASA Astrophysics Data System (ADS)

    Tse, Shutong; Bradbury, Laura; Wan, Justin W. L.; Djambazian, Haig; Sladek, Robert; Hudson, Thomas

    2009-02-01

    Segmentation of brightfield cell images from microscopy is challenging in several ways. The contrast between cells and the background is low. Cells are usually surrounded by "halo", an optical artifact common in brightfield images. Also, cell divisions occur frequently, which raises the issue of topological change to segmentation. In this paper, we present a robust segmentation method based on the watershed and level set methods. Instead of heuristically locate where the initial markers for watershed should be, we apply a multiphase level set marker extraction to determine regions inside a cell. In contrast with the standard level set segmentation where only one level set function is used, we apply multiple level set functions (usually 3) to capture the different intensity levels in a cell image. This is particularly important to be able to distinguish regions of similar but different intensity levels in low contrast images. All the pixels obtained will be used as an initial marker for watershed. The region growing process of watershed will capture the rest of the cell until it hits the halo which serves as a "wall" to stop the expansion. By using these relatively large number of points as markers together with watershed, we show that the low contrast cell boundary can be captured correctly. Furthermore, we present a technique for watershed and level set to detect cell division automatically with no special human attention. Finally, we present segmentation results of C2C12 cells in brightfield images to illustrate the effectiveness of our method.

  2. The relative contribution of viral and bacterial sexually transmitted infections on HIV acquisition in southern African women in the Methods for Improving Reproductive Health in Africa study.

    PubMed

    Venkatesh, K K; van der Straten, A; Cheng, H; Montgomery, E T; Lurie, M N; Chipato, T; Ramjee, G; Blanchard, K; Padian, N S; Mayer, K H; de Bruyn, G

    2011-04-01

    We assess the relative contribution of viral and bacterial sexually transmitted infections (STIs) on HIV acquisition among southern African women in a nested case-control study within the Methods for Improving Reproductive Health in Africa (MIRA) trial. Cases were women with incident HIV infection; controls were HIV-uninfected at the time of case seroconversion selected in a 1 to 3 case to control ratio (risk-set sampling), matched on study site and time of follow-up. Conditional logistic regression models were used to calculate adjusted odds ratios (AORs) and population-attributable fractions (PAF). Among 4948 enrolled women, we analysed 309 cases and 927 controls. The overall HIV incidence rate was 4.0 per 100 women-years. The incidence of HIV infection was markedly higher in women who had prevalent Herpes simplex virus type 2 (HSV-2) (AOR: 2.14; 95% confidence interval [CI]: 1.55-2.96), incident HSV-2 (AOR: 4.43; 95% CI: 1.77-11.05) and incident Neisseria gonorrhoeae (AOR: 6.92; 95% CI: 3.01-15.90). The adjusted PAF of HIV incidence for prevalent HSV-2 was 29.0% (95% CI: 16.8-39.3), for incident HSV-2 2.1% (95% CI: 0.6-3.6) and for incident N. gonorrhoeae 4.1% (95% CI: 2.5-5.8). Women's greatest risk factors for HIV acquisition were incident bacterial and viral STIs. Women-centred interventions aimed at decreasing HIV incidence in young African women need to address these common co-morbid conditions. PMID:21515755

  3. Use of simulated data sets to evaluate the fidelity of Metagenomicprocessing methods

    SciTech Connect

    Mavromatis, Konstantinos; Ivanova, Natalia; Barry, Kerri; Shapiro, Harris; Goltsman, Eugene; McHardy, Alice C.; Rigoutsos, Isidore; Salamov, Asaf; Korzeniewski, Frank; Land, Miriam; Lapidus, Alla; Grigoriev, Igor; Richardson, Paul; Hugenholtz, Philip; Kyrpides, Nikos C.

    2006-12-01

    Metagenomics is a rapidly emerging field of research for studying microbial communities. To evaluate methods presently used to process metagenomic sequences, we constructed three simulated data sets of varying complexity by combining sequencing reads randomly selected from 113 isolate genomes. These data sets were designed to model real metagenomes in terms of complexity and phylogenetic composition. We assembled sampled reads using three commonly used genome assemblers (Phrap, Arachne and JAZZ), and predicted genes using two popular gene finding pipelines (fgenesb and CRITICA/GLIMMER). The phylogenetic origins of the assembled contigs were predicted using one sequence similarity--based (blast hit distribution) and two sequence composition--based (PhyloPythia, oligonucleotide frequencies) binning methods. We explored the effects of the simulated community structure and method combinations on the fidelity of each processing step by comparison to the corresponding isolate genomes. The simulated data sets are available online to facilitate standardized benchmarking of tools for metagenomic analysis.

  4. Influences on HIV Testing among Young African-American Men Who Have Sex with Men and the Moderating Effect of the Geographic Setting

    ERIC Educational Resources Information Center

    Mashburn, Andrew J.; Peterson, John L.; Bakeman, Roger; Miller, Robin L.; Clark, Leslie F.

    2004-01-01

    This study examined the influence of demographic characteristics, risk behaviors, knowledge, and psychosocial variables on HIV testing among a sample (n = 551) of young African-American men who have sex with men (MSM) from three cities--Atlanta (n = 241), Birmingham (n = 174), and Chicago (n = 136). Among the entire sample of young men, age,…

  5. The Effects of Check-In Check-Out on the Social and Academic Planning and Outcomes of African-American Males in an Urban Secondary Setting

    ERIC Educational Resources Information Center

    Toms, Ozalle Marie

    2012-01-01

    According to Planty et al. (2009) in 2006, nearly 3.3 million students in the United States received out of school suspensions, demonstrating that exclusionary discipline is on the rise and a frequently used practice in schools across the country. Research shows that African Americans are suspended at higher rates and are more likely to receive…

  6. Studying learning in the healthcare setting: the potential of quantitative diary methods.

    PubMed

    Ciere, Yvette; Jaarsma, Debbie; Visser, Annemieke; Sanderman, Robbert; Snippe, Evelien; Fleer, Joke

    2015-08-01

    Quantitative diary methods are longitudinal approaches that involve the repeated measurement of aspects of peoples' experience of daily life. In this article, we outline the main characteristics and applications of quantitative diary methods and discuss how their use may further research in the field of medical education. Quantitative diary methods offer several methodological advantages, such as measuring aspects of learning with great detail, accuracy and authenticity. Moreover, they enable researchers to study how and under which conditions learning in the health care setting occurs and in which way learning can be promoted. Hence, quantitative diary methods may contribute to theory development and the optimization of teaching methods in medical education.

  7. Comparison of Statistical Methods for Estimating Genetic Admixture in a Lung Cancer Study of African Americans and Latinos

    PubMed Central

    Selvin, Steve; Hansen, Helen M.; Barcellos, Lisa F.; Wrensch, Margaret R.; Sison, Jennette D.; Quesenberry, Charles P.; Kittles, Rick A.; Silva, Gabriel; Buffler, Patricia A.; Seldin, Michael F.; Wiencke, John K.

    2008-01-01

    A variety of methods are available for estimating genetic admixture proportions in populations; however, few investigators have conducted detailed comparisons using empirical data. The authors characterized admixture proportions among self-identified African Americans (n = 535) and Latinos (n = 412) living in the San Francisco Bay Area who participated in a lung cancer case-control study (1998–2003). Individual estimates of genetic ancestry based on 184 informative markers were obtained from a Bayesian approach and 2 maximum likelihood approaches and were compared using descriptive statistics, Pearson correlation coefficients, and Bland-Altman plots. Case-control differences in individual admixture proportions were assessed using 2-sample t tests and logistic regression analysis. Results indicated that Bayesian and frequentist approaches to estimating admixture provide similar estimates and inferences. No difference was observed in admixture proportions between African-American cases and controls, but Latino cases and controls significantly differed according to Amerindian and European genetic ancestry. Differences in admixture proportions between Latino cases and controls were not unexpected, since cases were more likely to have been born in the United States. Genetic admixture proportions provide a quantitative measure of ancestry differences among Latinos that can be used in analyses of genetic risk factors. PMID:18791191

  8. Study on the RF Set Point for the PEFP DTL by using a phase scan method

    NASA Astrophysics Data System (ADS)

    Jang, Ji-Ho; Kwon, Hyeok-Jung; Cho, Yong-Sub

    2012-12-01

    The drift tube linac (DTL) is used to accelerate proton beams from 20 MeV to 100 MeV in the linear accelerator of the Proton Engineering Frontier Project (PEFP). The phase scan signature method is a common technique to determine the radio-frequency (rf) set point, including the rf amplitude and phase, in DTL tanks. In this work, we applied the phase scan method to the first tank of the PEFP's DTL in order to study the procedure for determining the rf set point by using artificial experimental data generated by using the PARMILA code.

  9. Breast mass segmentation in digital mammography based on pulse coupled neural network and level set method

    NASA Astrophysics Data System (ADS)

    Xie, Weiying; Ma, Yide; Li, Yunsong

    2015-05-01

    A novel approach to mammographic image segmentation, termed as PCNN-based level set algorithm, is presented in this paper. Just as its name implies, a method based on pulse coupled neural network (PCNN) in conjunction with the variational level set method for medical image segmentation. To date, little work has been done on detecting the initial zero level set contours based on PCNN algorithm for latterly level set evolution. When all the pixels of the input image are fired by PCNN, the small pixel value will be a much more refined segmentation. In mammographic image, the breast tumor presents big pixel value. Additionally, the mammographic image with predominantly dark region, so that we firstly obtain the negative of mammographic image with predominantly dark region except the breast tumor before all the pixels of an input image are fired by PCNN. Therefore, in here, PCNN algorithm is employed to achieve mammary-specific, initial mass contour detection. After that, the initial contours are all extracted. We define the extracted contours as the initial zero level set contours for automatic mass segmentation by variational level set in mammographic image analysis. What's more, a new proposed algorithm improves external energy of variational level set method in terms of mammographic images in low contrast. In accordance with the gray scale of mass region in mammographic image is higher than the region surrounded, so the Laplace operator is used to modify external energy, which could make the bright spot becoming much brighter than the surrounded pixels in the image. A preliminary evaluation of the proposed method performs on a known public database namely MIAS, rather than synthetic images. The experimental results demonstrate that our proposed approach can potentially obtain better masses detection results in terms of sensitivity and specificity. Ultimately, this algorithm could lead to increase both sensitivity and specificity of the physicians' interpretation of

  10. A novel method to quantify gene set functional association based on gene ontology.

    PubMed

    Lv, Sali; Li, Yan; Wang, Qianghu; Ning, Shangwei; Huang, Teng; Wang, Peng; Sun, Jie; Zheng, Yan; Liu, Weisha; Ai, Jing; Li, Xia

    2012-05-01

    Numerous gene sets have been used as molecular signatures for exploring the genetic basis of complex disorders. These gene sets are distinct but related to each other in many cases; therefore, efforts have been made to compare gene sets for studies such as those evaluating the reproducibility of different experiments. Comparison in terms of biological function has been demonstrated to be helpful to biologists. We improved the measurement of semantic similarity to quantify the functional association between gene sets in the context of gene ontology and developed a web toolkit named Gene Set Functional Similarity (GSFS; http://bioinfo.hrbmu.edu.cn/GSFS). Validation based on protein complexes for which the functional associations are known demonstrated that the GSFS scores tend to be correlated with sequence similarity scores and that complexes with high GSFS scores tend to be involved in the same functional catalogue. Compared with the pairwise method and the annotation method, the GSFS shows better discrimination and more accurately reflects the known functional catalogues shared between complexes. Case studies comparing differentially expressed genes of prostate tumour samples from different microarray platforms and identifying coronary heart disease susceptibility pathways revealed that the method could contribute to future studies exploring the molecular basis of complex disorders.

  11. Study of burn scar extraction automatically based on level set method using remote sensing data.

    PubMed

    Liu, Yang; Dai, Qin; Liu, Jianbo; Liu, ShiBin; Yang, Jin

    2014-01-01

    Burn scar extraction using remote sensing data is an efficient way to precisely evaluate burn area and measure vegetation recovery. Traditional burn scar extraction methodologies have no well effect on burn scar image with blurred and irregular edges. To address these issues, this paper proposes an automatic method to extract burn scar based on Level Set Method (LSM). This method utilizes the advantages of the different features in remote sensing images, as well as considers the practical needs of extracting the burn scar rapidly and automatically. This approach integrates Change Vector Analysis (CVA), Normalized Difference Vegetation Index (NDVI) and the Normalized Burn Ratio (NBR) to obtain difference image and modifies conventional Level Set Method Chan-Vese (C-V) model with a new initial curve which results from a binary image applying K-means method on fitting errors of two near-infrared band images. Landsat 5 TM and Landsat 8 OLI data sets are used to validate the proposed method. Comparison with conventional C-V model, OSTU algorithm, Fuzzy C-mean (FCM) algorithm are made to show that the proposed approach can extract the outline curve of fire burn scar effectively and exactly. The method has higher extraction accuracy and less algorithm complexity than that of the conventional C-V model.

  12. Study of burn scar extraction automatically based on level set method using remote sensing data.

    PubMed

    Liu, Yang; Dai, Qin; Liu, Jianbo; Liu, ShiBin; Yang, Jin

    2014-01-01

    Burn scar extraction using remote sensing data is an efficient way to precisely evaluate burn area and measure vegetation recovery. Traditional burn scar extraction methodologies have no well effect on burn scar image with blurred and irregular edges. To address these issues, this paper proposes an automatic method to extract burn scar based on Level Set Method (LSM). This method utilizes the advantages of the different features in remote sensing images, as well as considers the practical needs of extracting the burn scar rapidly and automatically. This approach integrates Change Vector Analysis (CVA), Normalized Difference Vegetation Index (NDVI) and the Normalized Burn Ratio (NBR) to obtain difference image and modifies conventional Level Set Method Chan-Vese (C-V) model with a new initial curve which results from a binary image applying K-means method on fitting errors of two near-infrared band images. Landsat 5 TM and Landsat 8 OLI data sets are used to validate the proposed method. Comparison with conventional C-V model, OSTU algorithm, Fuzzy C-mean (FCM) algorithm are made to show that the proposed approach can extract the outline curve of fire burn scar effectively and exactly. The method has higher extraction accuracy and less algorithm complexity than that of the conventional C-V model. PMID:24503563

  13. [Scaling methods applied to set priorities in training programs in organizations].

    PubMed

    Sanduvete Chaves, Susana; Barbero García, María Isabel; Chacón Moscoso, Salvador; Pérez-Gil, J Antonio; Holgado Tello, F Pablo; Sánchez Martín, Milagrosa; Lozano Lozano, J Antonio

    2009-11-01

    Criteria to assess the needs in order to plan training programs are not usually defined explicitly in organizational contexts. We propose scaling methods as a feasible and useful procedure to set priorities of training programs; also, we propose the most suitable method for this intervention context. 404 employees from a public organization completed an ad hoc questionnaire to assess training needs in different areas from 2004 to 2006; concretely, 117, 75 and 286 stimuli were scaled, respectively. Then, four scaling methods were compared: Dunn-Rankin's method and three methods derived from Thurstone's Law of Categorical Judgment--ranking, successive intervals and equal-appearing intervals. The feasibility and utility of these scaling methods to solve the problems described is shown. Taking into account the most accurate compared methods, we propose ranking as the most parsimonious method (with regard to procedure simplicity). Future research developments are described.

  14. [Narrow band multi-region level set method for remote sensing image].

    PubMed

    Fang, Jiang-Xiong; Tu, En-Mei; Yang, Jie; Jia, Zhen-Hong; Nikola, Kasabov

    2011-11-01

    Massive redundant contours happen when the classical Chan-Vese (C-V) model is used to segment remote sensing images, which have interlaced edges. What's more, this model can't segment homogeneous objects with multiple regions. In order to overcome this limitation of C-V model, narrow band multiple level set method is proposed. The use of N-1 curves is required for the segmentation of N regions and each curve represents one region. First, the level set model to establish an independent multi-region region can eliminate the redundant contours and avoids the problems of vacuum and overlap. Then, narrow band approach to level set method can reduce the computational cost. Experimental results of remote image verify that our model is efficient and accurate.

  15. A Cartesian Adaptive Level Set Method for Two-Phase Flows

    NASA Technical Reports Server (NTRS)

    Ham, F.; Young, Y.-N.

    2003-01-01

    In the present contribution we develop a level set method based on local anisotropic Cartesian adaptation as described in Ham et al. (2002). Such an approach should allow for the smallest possible Cartesian grid capable of resolving a given flow. The remainder of the paper is organized as follows. In section 2 the level set formulation for free surface calculations is presented and its strengths and weaknesses relative to the other free surface methods reviewed. In section 3 the collocated numerical method is described. In section 4 the method is validated by solving the 2D and 3D drop oscilation problem. In section 5 we present some results from more complex cases including the 3D drop breakup in an impulsively accelerated free stream, and the 3D immiscible Rayleigh-Taylor instability. Conclusions are given in section 6.

  16. Proposed SPAR Modeling Method for Quantifying Time Dependent Station Blackout Cut Sets

    SciTech Connect

    John A. Schroeder

    2010-06-01

    Abstract: The U.S. Nuclear Regulatory Commission’s (USNRC’s) Standardized Plant Analysis Risk (SPAR) models and industry risk models take similar approaches to analyzing the risk associated with loss of offsite power and station blackout (LOOP/SBO) events at nuclear reactor plants. In both SPAR models and industry models, core damage risk resulting from a LOOP/SBO event is analyzed using a combination of event trees and fault trees that produce cut sets that are, in turn, quantified to obtain a numerical estimate of the resulting core damage risk. A proposed SPAR method for quantifying the time-dependent cut sets is sometimes referred to as a convolution method. The SPAR method reflects assumptions about the timing of emergency diesel failures, the timing of subsequent attempts at emergency diesel repair, and the timing of core damage that may be different than those often used in industry models. This paper describes the proposed SPAR method.

  17. Commentary: A Response to Reckase's Conceptual Framework and Examples for Evaluating Standard Setting Methods

    ERIC Educational Resources Information Center

    Schulz, E. Matthew

    2006-01-01

    A look at real data shows that Reckase's psychometric theory for standard setting is not applicable to bookmark and that his simulations cannot explain actual differences between methods. It is suggested that exclusively test-centered, criterion-referenced approaches are too idealized and that a psychophysics paradigm and a theory of group…

  18. Monitoring Reading Growth: Goal Setting, Measurement Frequency, and Methods of Evaluation

    ERIC Educational Resources Information Center

    Jenkins, Joseph; Terjeson, Kari J.

    2011-01-01

    This study examined effects of goal setting, frequency of progress monitoring, and method of evaluating progress on the number of instructional change prompts generated by reading-curriculum-based measurements (CBM). Participants were 31 high-incidence special education students in grades 2-6 selected from 8 schools. Following baseline…

  19. Stabilised finite-element methods for solving the level set equation with mass conservation

    NASA Astrophysics Data System (ADS)

    Kabirou Touré, Mamadou; Fahsi, Adil; Soulaïmani, Azzeddine

    2016-01-01

    Finite-element methods are studied for solving moving interface flow problems using the level set approach and a stabilised variational formulation proposed in Touré and Soulaïmani (2012; Touré and Soulaïmani To appear in 2016), coupled with a level set correction method. The level set correction is intended to enhance the mass conservation satisfaction property. The stabilised variational formulation (Touré and Soulaïmani 2012; Touré and Soulaïmani, To appear in 2016) constrains the level set function to remain close to the signed distance function, while the mass conservation is a correction step which enforces the mass balance. The eXtended finite-element method (XFEM) is used to take into account the discontinuities of the properties within an element. XFEM is applied to solve the Navier-Stokes equations for two-phase flows. The numerical methods are numerically evaluated on several test cases such as time-reversed vortex flow, a rigid-body rotation of Zalesak's disc, sloshing flow in a tank, a dam-break over a bed, and a rising bubble subjected to buoyancy. The numerical results show the importance of satisfying global mass conservation to accurately capture the interface position.

  20. Self-adaptive projection methods for the multiple-sets split feasibility problem

    NASA Astrophysics Data System (ADS)

    Zhao, Jinling; Yang, Qingzhi

    2011-03-01

    The multiple-sets split feasibility problem (MSFP) is to find a point closest to the intersection of a family of closed convex sets in one space, such that its image under a linear transformation will be closest to the intersection of another family of closed convex sets in the image space. This problem arises in many practical fields, and it can be a model for many inverse problems. Noting that some existing algorithms require estimating the Lipschitz constant or calculating the largest eigenvalue of the matrix, in this paper, we first introduce a self-adaptive projection method by adopting Armijo-like searches to solve the MSFP, then we focus on a special case of the MSFP and propose a relaxed self-adaptive method by using projections onto half-spaces instead of those onto the original convex sets, which is much more practical. Convergence results for both methods are analyzed. Preliminary numerical results show that our methods are practical and promising for solving larger scale MSFPs.

  1. A Primer-Test Centered Equating Method for Setting Cut-Off Scores

    ERIC Educational Resources Information Center

    Zhu, Weimo; Plowman, Sharon Ann; Park, Youngsik

    2010-01-01

    This study evaluated the use of a new primary field test method based on test equating to address inconsistent classification among field tests. We analyzed students' information on the Progressive Aerobic Cardiovascular Endurance Run (PACER), mile run (MR), and VO[subscript 2]max from three data sets (college: n = 94; middle school: n = 39;…

  2. A regularized Newton method for solving equilibrium programming problems with an inexactly specified set

    NASA Astrophysics Data System (ADS)

    Antipin, A. S.; Vasil'Ev, F. P.; Stukalov, A. S.

    2007-01-01

    Unstable equilibrium problems are examined in which the objective function and the set where the equilibrium point is sought are specified inexactly. A regularized Newton method, combined with penalty functions, is proposed for solving such problems, and its convergence is analyzed. A regularizing operator is constructed.

  3. A fast level set method for synthetic aperture radar ocean image segmentation.

    PubMed

    Huang, Xiaoxia; Huang, Bo; Li, Hongga

    2009-01-01

    Segmentation of high noise imagery like Synthetic Aperture Radar (SAR) images is still one of the most challenging tasks in image processing. While level set, a novel approach based on the analysis of the motion of an interface, can be used to address this challenge, the cell-based iterations may make the process of image segmentation remarkably slow, especially for large-size images. For this reason fast level set algorithms such as narrow band and fast marching have been attempted. Built upon these, this paper presents an improved fast level set method for SAR ocean image segmentation. This competent method is dependent on both the intensity driven speed and curvature flow that result in a stable and smooth boundary. Notably, it is optimized to track moving interfaces for keeping up with the point-wise boundary propagation using a single list and a method of fast up-wind scheme iteration. The list facilitates efficient insertion and deletion of pixels on the propagation front. Meanwhile, the local up-wind scheme is used to update the motion of the curvature front instead of solving partial differential equations. Experiments have been carried out on extraction of surface slick features from ERS-2 SAR images to substantiate the efficacy of the proposed fast level set method.

  4. A Complementary Graphical Method for Reducing and Analyzing Large Data Sets*

    PubMed Central

    Jing, X.; Cimino, J. J.

    2014-01-01

    Summary Objectives Graphical displays can make data more understandable; however, large graphs can challenge human comprehension. We have previously described a filtering method to provide high-level summary views of large data sets. In this paper we demonstrate our method for setting and selecting thresholds to limit graph size while retaining important information by applying it to large single and paired data sets, taken from patient and bibliographic databases. Methods Four case studies are used to illustrate our method. The data are either patient discharge diagnoses (coded using the International Classification of Diseases, Clinical Modifications [ICD9-CM]) or Medline citations (coded using the Medical Subject Headings [MeSH]). We use combinations of different thresholds to obtain filtered graphs for detailed analysis. The thresholds setting and selection, such as thresholds for node counts, class counts, ratio values, p values (for diff data sets), and percentiles of selected class count thresholds, are demonstrated with details in case studies. The main steps include: data preparation, data manipulation, computation, and threshold selection and visualization. We also describe the data models for different types of thresholds and the considerations for thresholds selection. Results The filtered graphs are 1%-3% of the size of the original graphs. For our case studies, the graphs provide 1) the most heavily used ICD9-CM codes, 2) the codes with most patients in a research hospital in 2011, 3) a profile of publications on “heavily represented topics” in MEDLINE in 2011, and 4) validated knowledge about adverse effects of the medication of rosiglitazone and new interesting areas in the ICD9-CM hierarchy associated with patients taking the medication of pioglitazone. Conclusions Our filtering method reduces large graphs to a manageable size by removing relatively unimportant nodes. The graphical method provides summary views based on computation of usage

  5. Comparisons and Limitations of Gradient Augmented Level Set and Algebraic Volume of Fluid Methods

    NASA Astrophysics Data System (ADS)

    Anumolu, Lakshman; Ryddner, Douglas; Trujillo, Mario

    2014-11-01

    Recent numerical methods for implicit interface transport are generally presented as enjoying higher order of spatial-temporal convergence when compared to classical methods or less sophisticated approaches. However, when applied to test cases, which are designed to simulate practical industrial conditions, significant reduction in convergence is observed in higher-order methods, whereas for the less sophisticated approaches same convergence is achieved but a growth in the error norms occurs. This provides an opportunity to understand the underlying issues which causes this decrease in accuracy in both types of methods. As an example we consider the Gradient Augmented Level Set method (GALS) and a variant of the Volume of Fluid (VoF) method in our study. Results show that while both methods do suffer from a loss of accuracy, it is the higher order method that suffers more. The implication is a significant reduction in the performance advantage of the GALS method over the VoF scheme. Reasons for this lie in the behavior of the higher order derivatives, particular in situations where the level set field is highly distorted. For the VoF approach, serious spurious deformations of the interface are observed, albeit with a deceptive zero loss of mass.

  6. A GPU Accelerated Discontinuous Galerkin Conservative Level Set Method for Simulating Atomization

    NASA Astrophysics Data System (ADS)

    Jibben, Zechariah J.

    This dissertation describes a process for interface capturing via an arbitrary-order, nearly quadrature free, discontinuous Galerkin (DG) scheme for the conservative level set method (Olsson et al., 2005, 2008). The DG numerical method is utilized to solve both advection and reinitialization, and executed on a refined level set grid (Herrmann, 2008) for effective use of processing power. Computation is executed in parallel utilizing both CPU and GPU architectures to make the method feasible at high order. Finally, a sparse data structure is implemented to take full advantage of parallelism on the GPU, where performance relies on well-managed memory operations. With solution variables projected into a kth order polynomial basis, a k + 1 order convergence rate is found for both advection and reinitialization tests using the method of manufactured solutions. Other standard test cases, such as Zalesak's disk and deformation of columns and spheres in periodic vortices are also performed, showing several orders of magnitude improvement over traditional WENO level set methods. These tests also show the impact of reinitialization, which often increases shape and volume errors as a result of level set scalar trapping by normal vectors calculated from the local level set field. Accelerating advection via GPU hardware is found to provide a 30x speedup factor comparing a 2.0GHz Intel Xeon E5-2620 CPU in serial vs. a Nvidia Tesla K20 GPU, with speedup factors increasing with polynomial degree until shared memory is filled. A similar algorithm is implemented for reinitialization, which relies on heavier use of shared and global memory and as a result fills them more quickly and produces smaller speedups of 18x.

  7. Online monitoring of oil film using electrical capacitance tomography and level set method

    SciTech Connect

    Xue, Q. Ma, M.; Sun, B. Y.; Cui, Z. Q.; Wang, H. X.

    2015-08-15

    In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online.

  8. A novel method for purification of the endogenously expressed fission yeast Set2 complex.

    PubMed

    Suzuki, Shota; Nagao, Koji; Obuse, Chikashi; Murakami, Yota; Takahata, Shinya

    2014-05-01

    Chromatin-associated proteins are heterogeneously and dynamically composed. To gain a complete understanding of DNA packaging and basic nuclear functions, it is important to generate a comprehensive inventory of these proteins. However, biochemical purification of chromatin-associated proteins is difficult and is accompanied by concerns over complex stability, protein solubility and yield. Here, we describe a new method for optimized purification of the endogenously expressed fission yeast Set2 complex, histone H3K36 methyltransferase. Using the standard centrifugation procedure for purification, approximately half of the Set2 protein separated into the insoluble chromatin pellet fraction, making it impossible to recover the large amounts of soluble Set2. To overcome this poor recovery, we developed a novel protein purification technique termed the filtration/immunoaffinity purification/mass spectrometry (FIM) method, which eliminates the need for centrifugation. Using the FIM method, in which whole cell lysates were filtered consecutively through eight different pore sizes (53-0.8μm), a high yield of soluble FLAG-tagged Set2 was obtained from fission yeast. The technique was suitable for affinity purification and produced a low background. A mass spectrometry analysis of anti-FLAG immunoprecipitated proteins revealed that Rpb1, Rpb2 and Rpb3, which have all been reported previously as components of the budding yeast Set2 complex, were isolated from fission yeast using the FIM method. In addition, other subunits of RNA polymerase II and its phosphatase were also identified. In conclusion, the FIM method is valid for the efficient purification of protein complexes that separate into the insoluble chromatin pellet fraction during centrifugation.

  9. Online monitoring of oil film using electrical capacitance tomography and level set method

    NASA Astrophysics Data System (ADS)

    Xue, Q.; Sun, B. Y.; Cui, Z. Q.; Ma, M.; Wang, H. X.

    2015-08-01

    In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online.

  10. Online monitoring of oil film using electrical capacitance tomography and level set method.

    PubMed

    Xue, Q; Sun, B Y; Cui, Z Q; Ma, M; Wang, H X

    2015-08-01

    In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online. PMID:26329232

  11. Online monitoring of oil film using electrical capacitance tomography and level set method.

    PubMed

    Xue, Q; Sun, B Y; Cui, Z Q; Ma, M; Wang, H X

    2015-08-01

    In the application of oil-air lubrication system, electrical capacitance tomography (ECT) provides a promising way for monitoring oil film in the pipelines by reconstructing cross sectional oil distributions in real time. While in the case of small diameter pipe and thin oil film, the thickness of the oil film is hard to be observed visually since the interface of oil and air is not obvious in the reconstructed images. And the existence of artifacts in the reconstructions has seriously influenced the effectiveness of image segmentation techniques such as level set method. Besides, level set method is also unavailable for online monitoring due to its low computation speed. To address these problems, a modified level set method is developed: a distance regularized level set evolution formulation is extended to image two-phase flow online using an ECT system, a narrowband image filter is defined to eliminate the influence of artifacts, and considering the continuity of the oil distribution variation, the detected oil-air interface of a former image can be used as the initial contour for the detection of the subsequent frame; thus, the propagation from the initial contour to the boundary can be greatly accelerated, making it possible for real time tracking. To testify the feasibility of the proposed method, an oil-air lubrication facility with 4 mm inner diameter pipe is measured in normal operation using an 8-electrode ECT system. Both simulation and experiment results indicate that the modified level set method is capable of visualizing the oil-air interface accurately online.

  12. Benchmarking Methods and Data Sets for Ligand Enrichment Assessment in Virtual Screening

    PubMed Central

    Xia, Jie; Tilahun, Ermias Lemma; Reid, Terry-Elinor; Zhang, Liangren; Wang, Xiang Simon

    2014-01-01

    Retrospective small-scale virtual screening (VS) based on benchmarking data sets has been widely used to estimate ligand enrichments of VS approaches in the prospective (i.e. real-world) efforts. However, the intrinsic differences of benchmarking sets to the real screening chemical libraries can cause biased assessment. Herein, we summarize the history of benchmarking methods as well as data sets and highlight three main types of biases found in benchmarking sets, i.e. “analogue bias”, “artificial enrichment” and “false negative”. In addition, we introduced our recent algorithm to build maximum-unbiased benchmarking sets applicable to both ligand-based and structure-based VS approaches, and its implementations to three important human histone deacetylase (HDAC) isoforms, i.e. HDAC1, HDAC6 and HDAC8. The Leave-One-Out Cross-Validation (LOO CV) demonstrates that the benchmarking sets built by our algorithm are maximum-unbiased in terms of property matching, ROC curves and AUCs. PMID:25481478

  13. A hybrid semi-automatic method for liver segmentation based on level-set methods using multiple seed points.

    PubMed

    Yang, Xiaopeng; Yu, Hee Chul; Choi, Younggeun; Lee, Wonsup; Wang, Baojian; Yang, Jaedo; Hwang, Hongpil; Kim, Ji Hyun; Song, Jisoo; Cho, Baik Hwan; You, Heecheon

    2014-01-01

    The present study developed a hybrid semi-automatic method to extract the liver from abdominal computerized tomography (CT) images. The proposed hybrid method consists of a customized fast-marching level-set method for detection of an optimal initial liver region from multiple seed points selected by the user and a threshold-based level-set method for extraction of the actual liver region based on the initial liver region. The performance of the hybrid method was compared with those of the 2D region growing method implemented in OsiriX using abdominal CT datasets of 15 patients. The hybrid method showed a significantly higher accuracy in liver extraction (similarity index, SI=97.6 ± 0.5%; false positive error, FPE = 2.2 ± 0.7%; false negative error, FNE=2.5 ± 0.8%; average symmetric surface distance, ASD=1.4 ± 0.5mm) than the 2D (SI=94.0 ± 1.9%; FPE = 5.3 ± 1.1%; FNE=6.5 ± 3.7%; ASD=6.7 ± 3.8mm) region growing method. The total liver extraction time per CT dataset of the hybrid method (77 ± 10 s) is significantly less than the 2D region growing method (575 ± 136 s). The interaction time per CT dataset between the user and a computer of the hybrid method (28 ± 4 s) is significantly shorter than the 2D region growing method (484 ± 126 s). The proposed hybrid method was found preferred for liver segmentation in preoperative virtual liver surgery planning.

  14. Why does Japan use the probability method to set design flood?

    NASA Astrophysics Data System (ADS)

    Nakamura, S.; Oki, T.

    2015-12-01

    Design flood is hypothetical flood to make flood prevention plan. In Japan, a probability method based on precipitation data is used to define the scale of design flood: Tone River, the biggest river in Japan, is 1 in 200 years, Shinano River is 1 in 150 years, and so on. It is one of important socio-hydrological issue how to set reasonable and acceptable design flood in a changing world. The method to set design flood vary among countries. Although the probability method is also used in Netherland, but the base data is water level or discharge data and the probability is 1 in 1250 years (in fresh water section). On the other side, USA and China apply the maximum flood method which set the design flood based on the historical or probable maximum flood. This cases can leads a question: "what is the reason why the method vary among countries?" or "why does Japan use the probability method?" The purpose of this study is to clarify the historical process which the probability method was developed in Japan based on the literature. In the late 19the century, the concept of "discharge" and modern river engineering were imported by Dutch engineers, and modern flood prevention plans were developed in Japan. In these plans, the design floods were set based on the historical maximum method. Although the historical maximum method had been used until World War 2, however, the method was changed to the probability method after the war because of limitations of historical maximum method under the specific socio-economic situations: (1) the budget limitation due to the war and the GHQ occupation, (2) the historical floods: Makurazaki typhoon in 1945, Kathleen typhoon in 1947, Ione typhoon in 1948, and so on, attacked Japan and broke the record of historical maximum discharge in main rivers and the flood disasters made the flood prevention projects difficult to complete. Then, Japanese hydrologists imported the hydrological probability statistics from the West to take account of

  15. Periodical capacity setting methods for make-to-order multi-machine production systems

    PubMed Central

    Altendorfer, Klaus; Hübl, Alexander; Jodlbauer, Herbert

    2014-01-01

    The paper presents different periodical capacity setting methods for make-to-order, multi-machine production systems with stochastic customer required lead times and stochastic processing times to improve service level and tardiness. These methods are developed as decision support when capacity flexibility exists, such as, a certain range of possible working hours a week for example. The methods differ in the amount of information used whereby all are based on the cumulated capacity demand at each machine. In a simulation study the methods’ impact on service level and tardiness is compared to a constant provided capacity for a single and a multi-machine setting. It is shown that the tested capacity setting methods can lead to an increase in service level and a decrease in average tardiness in comparison to a constant provided capacity. The methods using information on processing time and customer required lead time distribution perform best. The results found in this paper can help practitioners to make efficient use of their flexible capacity. PMID:27226649

  16. Accurate Adaptive Level Set Method and Sharpening Technique for Three Dimensional Deforming Interfaces

    NASA Technical Reports Server (NTRS)

    Kim, Hyoungin; Liou, Meng-Sing

    2011-01-01

    In this paper, we demonstrate improved accuracy of the level set method for resolving deforming interfaces by proposing two key elements: (1) accurate level set solutions on adapted Cartesian grids by judiciously choosing interpolation polynomials in regions of different grid levels and (2) enhanced reinitialization by an interface sharpening procedure. The level set equation is solved using a fifth order WENO scheme or a second order central differencing scheme depending on availability of uniform stencils at each grid point. Grid adaptation criteria are determined so that the Hamiltonian functions at nodes adjacent to interfaces are always calculated by the fifth order WENO scheme. This selective usage between the fifth order WENO and second order central differencing schemes is confirmed to give more accurate results compared to those in literature for standard test problems. In order to further improve accuracy especially near thin filaments, we suggest an artificial sharpening method, which is in a similar form with the conventional re-initialization method but utilizes sign of curvature instead of sign of the level set function. Consequently, volume loss due to numerical dissipation on thin filaments is remarkably reduced for the test problems

  17. Method and Basis Set Analysis of Oxorhenium(V) Complexes for Theoretical Calculations

    PubMed Central

    Demoin, Dustin Wayne; Li, Yawen; Jurisson, Silvia S.; Deakyne, Carol A.

    2012-01-01

    A variety of method and basis set combinations has been evaluated for monooxorhenium(V) complexes with N, O, P, S, Cl, and Se donor atoms. The geometries and energies obtained are compared to both high-level computations and literature structures. These calculations show that the PBE0 method outperforms the B3LYP method with respect to both structure and energetics. The combination of 6-31G** basis set on the nonmetal atoms and LANL2TZ effective core potential on the rhenium center gives reliable equilibrium structures with minimal computational resources for both model and literature compounds. Single-point energy calculations at the PBE0/LANL2TZ,6-311+G* level of theory are recommended for energetics. PMID:23087847

  18. Image restoration by a novel method of parallel projection onto constraint sets.

    PubMed

    Kotzer, T; Cohen, N; Shamir, J

    1995-05-15

    Image restoration from degraded observations and from properties that the image is supposed to satisfy has been approached by the method of projections onto convex constraint sets. Previous attempts have incorporated only partially the knowledge that we possess about the image to be restored because of difficulties in the implementation of some of the projections. In the parallel-projection algorithm presented here the a priori knowledge can be fully exploited. Moreover, the algorithm operates well even if the constraints are nonconvex and/or if the constraints have an empty intersection, without a limitation on the (finite) number of constraint sets.

  19. A localized re-initialization equation for the conservative level set method

    NASA Astrophysics Data System (ADS)

    McCaslin, Jeremy O.; Desjardins, Olivier

    2014-04-01

    The conservative level set methodology for interface transport is modified to allow for localized level set re-initialization. This approach is suitable to applications in which there is a significant amount of spatial variability in level set transport. The steady-state solution of the modified re-initialization equation matches that of the original conservative level set provided an additional Eikonal equation is solved, which can be done efficiently through a fast marching method (FMM). Implemented within the context of the accurate conservative level set method (ACLS) (Desjardins et al., 2008, [6]), the FMM solution of this Eikonal equation comes at no additional cost. A metric for the appropriate amount of local re-initialization is proposed based on estimates of local flow deformation and numerical diffusion. The method is compared to standard global re-initialization for two test cases, yielding the expected results that minor differences are observed for Zalesak's disk, and improvements in both mass conservation and interface topology are seen for a drop deforming in a vortex. Finally, the method is applied to simulation of a viscously damped standing wave and a three-dimensional drop impacting on a shallow pool. Negligible differences are observed for the standing wave, as expected. For the last case, results suggest that spatially varying re-initialization provides a reduction in spurious interfacial corrugations, improvements in the prediction of radial growth of the splashing lamella, and a reduction in conservation errors, as well as a reduction in overall computational cost that comes from improved conditioning of the pressure Poisson equation due to the removal of spurious corrugations.

  20. A Novel Fractal Coding Method Based on M-J Sets

    PubMed Central

    Sun, Yuanyuan; Xu, Rudan; Chen, Lina; Kong, Ruiqing; Hu, Xiaopeng

    2014-01-01

    In this paper, we present a novel fractal coding method with the block classification scheme based on a shared domain block pool. In our method, the domain block pool is called dictionary and is constructed from fractal Julia sets. The image is encoded by searching the best matching domain block with the same BTC (Block Truncation Coding) value in the dictionary. The experimental results show that the scheme is competent both in encoding speed and in reconstruction quality. Particularly for large images, the proposed method can avoid excessive growth of the computational complexity compared with the traditional fractal coding algorithm. PMID:25010686

  1. Identifying outcome research methods that facilitate data collection in the behavioral healthcare setting

    SciTech Connect

    Smith, E.R.; Brooker, C.

    1996-12-31

    Outcome research is a necessary and increasingly prevalent part of any behavioral healthcare program. With the large set of available choices for beginning outcome research, it is of value to weigh the benefits and liabilities of using the various methods. This paper reviews methods for deciding what variables to measure, types of measures and methods for using them, and sources of tools that allow for data processing, analysis, and presentation. We will also address the organizational cultural issues that influence success and failure in the outcome research process. Finally, the value of simply beginning the research process will be emphasized.

  2. A mixed methods study of health and social disparities among substance-using African American/Black men who have sex with men

    PubMed Central

    Buttram, Mance E.; Kurtz, Steven P.

    2014-01-01

    African American/Black men who have sex with men (MSM) in the U.S. experience health and social disparities at greater rates than MSM of other races/ethnicities, including HIV infection and substance use. This mixed methods paper presents: 1) a quantitative examination of health and social disparities among a sample of substance-using African American/Black MSM (N=108), compared to Caucasian/White MSM (N=250), and 2) in-depth qualitative data from a subsample of African American/Black MSM (N=21) in order to contextualize the quantitative data. Findings indicate that compared to Caucasian/White MSM, African American/Black MSM experienced a wide range of health and social disparities including: substance use and dependence; buying, trading or selling sex; educational attainment; employment; homelessness; identifying as gay; HIV status; arrest history; social support; and satisfaction with one's living situation. Qualitative data suggests that structural interventions that address homophobia and the social environment would be likely to mitigate many of the health and social disparities experienced by African American/Black MSM. PMID:25960944

  3. A mixed methods study of health and social disparities among substance-using African American/Black men who have sex with men.

    PubMed

    Buttram, Mance E; Kurtz, Steven P

    2015-03-01

    African American/Black men who have sex with men (MSM) in the U.S. experience health and social disparities at greater rates than MSM of other races/ethnicities, including HIV infection and substance use. This mixed methods paper presents: 1) a quantitative examination of health and social disparities among a sample of substance-using African American/Black MSM (N=108), compared to Caucasian/White MSM (N=250), and 2) in-depth qualitative data from a subsample of African American/Black MSM (N=21) in order to contextualize the quantitative data. Findings indicate that compared to Caucasian/White MSM, African American/Black MSM experienced a wide range of health and social disparities including: substance use and dependence; buying, trading or selling sex; educational attainment; employment; homelessness; identifying as gay; HIV status; arrest history; social support; and satisfaction with one's living situation. Qualitative data suggests that structural interventions that address homophobia and the social environment would be likely to mitigate many of the health and social disparities experienced by African American/Black MSM. PMID:25960944

  4. 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. ...

  5. Dynamic multi-source X-ray tomography using a spacetime level set method

    NASA Astrophysics Data System (ADS)

    Niemi, Esa; Lassas, Matti; Kallonen, Aki; Harhanen, Lauri; Hämäläinen, Keijo; Siltanen, Samuli

    2015-06-01

    A novel variant of the level set method is introduced for dynamic X-ray tomography. The target is allowed to change in time while being imaged by one or several source-detector pairs at a relatively high frame-rate. The algorithmic approach is motivated by the results in [22], showing that the modified level set method can tolerate highly incomplete projection data in stationary tomography. Furthermore, defining the level set function in spacetime enforces temporal continuity in the dynamic tomography context considered here. The tomographic reconstruction is found as a minimizer of a nonlinear functional. The functional contains a regularization term penalizing the L2 norms of up to n derivatives of the reconstruction. The case n = 1 is shown to be equivalent to a convex Tikhonov problem that has a unique minimizer. For n ≥ 2 the existence of a minimizer is proved under certain assumptions on the signal-to-noise ratio and the size of the regularization parameter. Numerical examples with both simulated and measured dynamic X-ray data are included, and the proposed method is found to yield reconstructions superior to standard methods such as FBP or non-negativity constrained Tikhonov regularization and favorably comparable to those of total variation regularization. Furthermore, the methodology can be adapted to a wide range of measurement arrangements with one or more X-ray sources.

  6. Vascular Tree Segmentation in Medical Images Using Hessian-Based Multiscale Filtering and Level Set Method

    PubMed Central

    Jin, Jiaoying; Yang, Linjun; Zhang, Xuming

    2013-01-01

    Vascular segmentation plays an important role in medical image analysis. A novel technique for the automatic extraction of vascular trees from 2D medical images is presented, which combines Hessian-based multiscale filtering and a modified level set method. In the proposed algorithm, the morphological top-hat transformation is firstly adopted to attenuate background. Then Hessian-based multiscale filtering is used to enhance vascular structures by combining Hessian matrix with Gaussian convolution to tune the filtering response to the specific scales. Because Gaussian convolution tends to blur vessel boundaries, which makes scale selection inaccurate, an improved level set method is finally proposed to extract vascular structures by introducing an external constrained term related to the standard deviation of Gaussian function into the traditional level set. Our approach was tested on synthetic images with vascular-like structures and 2D slices extracted from real 3D abdomen magnetic resonance angiography (MRA) images along the coronal plane. The segmentation rates for synthetic images are above 95%. The results for MRA images demonstrate that the proposed method can extract most of the vascular structures successfully and accurately in visualization. Therefore, the proposed method is effective for the vascular tree extraction in medical images. PMID:24348738

  7. Coresets vs clustering: comparison of methods for redundancy reduction in very large white matter fiber sets

    NASA Astrophysics Data System (ADS)

    Alexandroni, Guy; Zimmerman Moreno, Gali; Sochen, Nir; Greenspan, Hayit

    2016-03-01

    Recent advances in Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) of white matter in conjunction with improved tractography produce impressive reconstructions of White Matter (WM) pathways. These pathways (fiber sets) often contain hundreds of thousands of fibers, or more. In order to make fiber based analysis more practical, the fiber set needs to be preprocessed to eliminate redundancies and to keep only essential representative fibers. In this paper we demonstrate and compare two distinctive frameworks for selecting this reduced set of fibers. The first framework entails pre-clustering the fibers using k-means, followed by Hierarchical Clustering and replacing each cluster with one representative. For the second clustering stage seven distance metrics were evaluated. The second framework is based on an efficient geometric approximation paradigm named coresets. Coresets present a new approach to optimization and have huge success especially in tasks requiring large computation time and/or memory. We propose a modified version of the coresets algorithm, Density Coreset. It is used for extracting the main fibers from dense datasets, leaving a small set that represents the main structures and connectivity of the brain. A novel approach, based on a 3D indicator structure, is used for comparing the frameworks. This comparison was applied to High Angular Resolution Diffusion Imaging (HARDI) scans of 4 healthy individuals. We show that among the clustering based methods, that cosine distance gives the best performance. In comparing the clustering schemes with coresets, Density Coreset method achieves the best performance.

  8. Acceptability of a Community-Based Outreach HIV-Testing Intervention Using Oral Fluid Collection Devices and Web-Based HIV Test Result Collection Among Sub-Saharan African Migrants: A Mixed-Method Study

    PubMed Central

    Manirankunda, Lazare; Platteau, Tom; Albers, Laura; Fransen, Katrien; Vermoesen, Tine; Namanya, Fiona; Nöstlinger, Christiana

    2016-01-01

    fluid collection devices were well accepted mainly because sub-Saharan African migrants dislike blood taking. For some participants, the method raised concerns about HIV transmission via saliva. The combination of information sessions, testimonies, and oral fluid collection devices was perceived as effectively reducing thresholds to participation. Acceptability of the intervention differed between individual participants and settings. Acceptance was higher among women, in churches and settings where community leaders were engaged in HIV awareness raising. Higher preventive outcomes were observed in settings with lower acceptance. The presence of the intervention team visualized the magnitude of the HIV epidemic to the public and promoted HIV testing uptake at large, for example, those who declined indicated they would take up testing later. Conclusions When accompanied by tailored provision of information, outreach HIV testing interventions adopting a community-based approach and innovative methods such as Web-based result collection and oral fluid collection devices are acceptable and reduce thresholds for HIV testing uptake. The swab2know intervention was able to reach sub-Saharan African migrants at risk of HIV infection, and with limited access to regular HIV testing. Among nontesters, the intervention contributed to awareness raising and therefore has a place in a multipronged HIV test promotion strategy. PMID:27493067

  9. Hard Bigotry, Low Expectations and Soft Support: Educating American African Boys in the United States with the Warrior Method

    ERIC Educational Resources Information Center

    Winbush, Raymond A.

    2013-01-01

    Educating American Africans boys has been a mixture of political rhetoric, educational pedagogy, and historical neglect. Although American African educators have produced several models for effectively educating Black boys, most of them are dismissed as too "radical" by White researchers who have little understanding or experience in…

  10. 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.

  11. A mass conserving level set method for detailed numerical simulation of liquid atomization

    SciTech Connect

    Luo, Kun; Shao, Changxiao; Yang, Yue; Fan, Jianren

    2015-10-01

    An improved mass conserving level set method for detailed numerical simulations of liquid atomization is developed to address the issue of mass loss in the existing level set method. This method introduces a mass remedy procedure based on the local curvature at the interface, and in principle, can ensure the absolute mass conservation of the liquid phase in the computational domain. Three benchmark cases, including Zalesak's disk, a drop deforming in a vortex field, and the binary drop head-on collision, are simulated to validate the present method, and the excellent agreement with exact solutions or experimental results is achieved. It is shown that the present method is able to capture the complex interface with second-order accuracy and negligible additional computational cost. The present method is then applied to study more complex flows, such as a drop impacting on a liquid film and the swirling liquid sheet atomization, which again, demonstrates the advantages of mass conservation and the capability to represent the interface accurately.

  12. Phase field and level set methods for modeling solute precipitation and/or dissolution

    SciTech Connect

    Zhijie Xu; Hai Huang; Paul Meakin

    2012-01-01

    The dynamics of solid-liquid interfaces controlled by solute precipitation and/or dissolution due to the chemical reaction at the interface were computed in two dimensions using a phase field models. Sharp-interface asymptotic analysis demonstrated that the phase field solutions should converge to the proper sharp-interface precipitation/dissolution limit. For the purpose of comparison, the numerical solution of the sharp-interface model for solute precipitation/dissolution was directly solved using a level set method. In general, the phase field results are found in good agreement with the level set results for all reaction rates and geometry configurations investigated. Present study supports the applications of both methods to more complicated and realistic reactive systems, including the nuclear waste release and mineral precipitation and dissolution

  13. Phase field and level set methods for modeling solute precipitation and/or dissolution

    SciTech Connect

    Xu, Zhijie; Huang, Hai; Li, Xiaoyi; Meakin, Paul

    2012-01-02

    The dynamics of solid-liquid interfaces controlled by solute precipitation and/or dissolution due to the chemical reaction at the interface were computed in two dimensions using a phase field models. Sharp-interface asymptotic analysis demonstrated that the phase field solutions should converge to the proper sharp-interface precipitation/dissolution limit. For the purpose of comparison, the numerical solution of the sharp-interface model for solute precipitation/dissolution was directly solved using a level set method. In general, the phase field results are found in good agreement with the level set results for all reaction rates and geometry configurations. Present study supports the applications of both methods to more complicated and realistic reactive systems.

  14. Parallel computation of level set method for 500 Hz visual servo control

    NASA Astrophysics Data System (ADS)

    Fei, Xianfeng; Igarashi, Yasunobu; Hashimoto, Koichi

    2008-11-01

    We propose a 2D microorganism tracking system using a parallel level set method and a column parallel vision system (CPV). This system keeps a single microorganism in the middle of the visual field under a microscope by visual servoing an automated stage. We propose a new energy function for the level set method. This function constrains an amount of light intensity inside the detected object contour to control the number of the detected objects. This algorithm is implemented in CPV system and computational time for each frame is 2 [ms], approximately. A tracking experiment for about 25 s is demonstrated. Also we demonstrate a single paramecium can be kept tracking even if other paramecia appear in the visual field and contact with the tracked paramecium.

  15. TOGETHER Project to Increase Understanding of the HIV Epidemic Among Sub-Saharan African Migrants: Protocol of Community-Based Participatory Mixed-Method Studies

    PubMed Central

    Vuylsteke, Bea; Manirankunda, Lazare; Deblonde, Jessika; Kint, Ilse; Namanya, Fiona; Fransen, Katrien; Colebunders, Robert; Laga, Marie; Adobea, Dorothy; Nöstlinger, Christiana

    2016-01-01

    Background Sub-Saharan African Migrants (SAM) are the second largest group affected by HIV/AIDS in Belgium and the rest of Western Europe. Increasing evidence shows that, more than previously thought, SAM are acquiring HIV in their host countries. This calls for a renewed focus on primary prevention. Yet, knowledge on the magnitude of the HIV epidemic among SAM (HIV prevalence estimates and proportions of undiagnosed HIV infections) and underlying drivers are scarce and limit the development of such interventions. Objective By applying a community-based participatory and mixed-methods approach, the TOGETHER project aims to deepen our understanding of HIV transmission dynamics, as well as inform future primary prevention interventions for this target group. Methods The TOGETHER project consists of a cross-sectional study to assess HIV prevalence and risk factors among SAM visiting community settings in Antwerp city, Belgium, and links an anonymous electronic self-reported questionnaire to oral fluid samples. Three formative studies informed this method: (1) a social mapping of community settings using an adaptation of the PLACE method; (2) a multiple case study aiming to identify factors that increase risk and vulnerability for HIV infection by triangulating data from life history interviews, lifelines, and patient files; and (3) an acceptability and feasibility study of oral fluid sampling in community settings using participant observations. Results Results have been obtained from 4 interlinked studies and will be described in future research. Conclusions Combining empirically tested and innovative epidemiological and social science methods, this project provides the first HIV prevalence estimates for a representative sample of SAM residing in a West European city. By triangulating qualitative and quantitative insights, the project will generate an in-depth understanding of the factors that increase risk and vulnerability for HIV infection among SAM. Based on this

  16. A method of hidden Markov model optimization for use with geophysical data sets

    NASA Technical Reports Server (NTRS)

    Granat, R. A.

    2003-01-01

    Geophysics research has been faced with a growing need for automated techniques with which to process large quantities of data. A successful tool must meet a number of requirements: it should be consistent, require minimal parameter tuning, and produce scientifically meaningful results in reasonable time. We introduce a hidden Markov model (HMM)-based method for analysis of geophysical data sets that attempts to address these issues.

  17. An adaptive level set method for shock-driven fluid-structure interaction

    SciTech Connect

    Deiterding, Ralf

    2007-01-01

    The fluid-structure interaction simulation of shock- and detonation-loaded structures requires numerical methods that can cope with large deformations as well as local topology changes. A robust, level-set-based shock-capturing fluid solver is described that allows coupling to any solid mechanics solver. As computational example, the elastic response of a thin steel panel, modeled with both shell and beam theory, to a shock wave in air is considered.

  18. A level-set adjoint-state method for crosswell transmission-reflection traveltime tomography

    NASA Astrophysics Data System (ADS)

    Li, Wenbin; Leung, Shingyu; Qian, Jianliang

    2014-10-01

    We propose a level-set adjoint-state method for crosswell traveltime tomography using both first-arrival transmission and reflection traveltime data. Since our entire formulation is based on solving eikonal and advection equations on finite-difference meshes, our traveltime tomography strategy is carried out without computing rays explicitly. We incorporate reflection traveltime data into the formulation so that possible reflectors (slowness interfaces) in the targeted subsurface model can be recovered as well as the slowness distribution itself. Since a reflector may assume a variety of irregular geometries, we propose to use a level-set function to implicitly parametrize the shape of a reflector. Therefore, a mismatch functional is established to minimize the traveltime data misfit with respect to both the slowness distribution and the level-set function, and the minimization is achieved by using a gradient descent method with gradients computed by solving adjoint state equations. To assess uncertainty or reliability of reconstructed slowness models, we introduce a labelling function to characterize first-arrival ray coverage of the computational domain, and this labelling function satisfies an advection equation. We apply fast-sweeping type methods to solve eikonal, adjoint-state and advection equations arising in our formulation. Numerical examples demonstrate that the proposed algorithm is robust to noise in the measurements, and can recover complicated structure even with little information on the reflector.

  19. Comparing simple root phenotyping methods on a core set of rice genotypes.

    PubMed

    Shrestha, R; Al-Shugeairy, Z; Al-Ogaidi, F; Munasinghe, M; Radermacher, M; Vandenhirtz, J; Price, A H

    2014-05-01

    Interest in belowground plant growth is increasing, especially in relation to arguments that shallow-rooted cultivars are efficient at exploiting soil phosphorus while deep-rooted ones will access water at depth. However, methods for assessing roots in large numbers of plants are diverse and direct comparisons of methods are rare. Three methods for measuring root growth traits were evaluated for utility in discriminating rice cultivars: soil-filled rhizotrons, hydroponics and soil-filled pots whose bottom was sealed with a non-woven fabric (a potential method for assessing root penetration ability). A set of 38 rice genotypes including the OryzaSNP set of 20 cultivars, additional parents of mapping populations and products of marker-assisted selection for root QTLs were assessed. A novel method of image analysis for assessing rooting angles from rhizotron photographs was employed. The non-woven fabric was the easiest yet least discriminatory method, while the rhizotron was highly discriminatory and allowed the most traits to be measured but required more than three times the labour of the other methods. The hydroponics was both easy and discriminatory, allowed temporal measurements, but is most likely to suffer from artefacts. Image analysis of rhizotrons compared favourably to manual methods for discriminating between cultivars. Previous observations that cultivars from the indica subpopulation have shallower rooting angles than aus or japonica cultivars were confirmed in the rhizotrons, and indica and temperate japonicas had lower maximum root lengths in rhizotrons and hydroponics. It is concluded that rhizotrons are the preferred method for root screening, particularly since root angles can be assessed.

  20. Setting health research priorities using the CHNRI method: IV. Key conceptual advances

    PubMed Central

    Rudan, Igor

    2016-01-01

    Introduction Child Health and Nutrition Research Initiative (CHNRI) started as an initiative of the Global Forum for Health Research in Geneva, Switzerland. Its aim was to develop a method that could assist priority setting in health research investments. The first version of the CHNRI method was published in 2007–2008. The aim of this paper was to summarize the history of the development of the CHNRI method and its key conceptual advances. Methods The guiding principle of the CHNRI method is to expose the potential of many competing health research ideas to reduce disease burden and inequities that exist in the population in a feasible and cost–effective way. Results The CHNRI method introduced three key conceptual advances that led to its increased popularity in comparison to other priority–setting methods and processes. First, it proposed a systematic approach to listing a large number of possible research ideas, using the “4D” framework (description, delivery, development and discovery research) and a well–defined “depth” of proposed research ideas (research instruments, avenues, options and questions). Second, it proposed a systematic approach for discriminating between many proposed research ideas based on a well–defined context and criteria. The five “standard” components of the context are the population of interest, the disease burden of interest, geographic limits, time scale and the preferred style of investing with respect to risk. The five “standard” criteria proposed for prioritization between research ideas are answerability, effectiveness, deliverability, maximum potential for disease burden reduction and the effect on equity. However, both the context and the criteria can be flexibly changed to meet the specific needs of each priority–setting exercise. Third, it facilitated consensus development through measuring collective optimism on each component of each research idea among a larger group of experts using a simple

  1. New Approach for Setting a Management Criterion in Microbiological Monitoring Using Rapid Microbiological Methods.

    PubMed

    Miyashita, Noe; Tanaka, Makoto; Gotoda, Ryusuke

    2015-01-01

    The application of rapid microbiological methods (RMM) to bacterial monitoring in pharmaceutical manufacturing processes is now a key topic, since timely microbiological data are critical for product release, continuous process improvement and quality control. An automated, highly sensitive detection system has been developed which can measure the amount of ATP in a sample in 2 h with one hundredfold more sensitive than the conventional ATP method. One of the major subjects for adoption and implementation of RMM is how to set the criterion value for practical microbial control. This value was conventionally been set by experimental rule and indicated as the number of colonies counted after incubation in a particular medium. We have adopted a new approach to set a criterion value which enables assessment in whether the status of the object is normal or not. By setting this criterion value, it is possible to conduct the microbiological control with the intended probability of false-positive and false-negative. In this approach the probability distribution model of the measurement value of each object in a normal status has been established by performing repetitive measurement of each object. We have suggested and verified the probability distribution form of the ATP measurement value using measurement data of the standard bacterial solution of Staphylococcus aureus. The theoretical value of the model was in good agreement with the actual measured value. The results suggest it is possible to set an applicable management criterion value using this model and to conduct new microbiological monitoring using RMM. PMID:26521822

  2. Approaches, tools and methods used for setting priorities in health research in the 21st century

    PubMed Central

    Yoshida, Sachiyo

    2016-01-01

    Background Health research is difficult to prioritize, because the number of possible competing ideas for research is large, the outcome of research is inherently uncertain, and the impact of research is difficult to predict and measure. A systematic and transparent process to assist policy makers and research funding agencies in making investment decisions is a permanent need. Methods To obtain a better understanding of the landscape of approaches, tools and methods used to prioritize health research, I conducted a methodical review using the PubMed database for the period 2001–2014. Results A total of 165 relevant studies were identified, in which health research prioritization was conducted. They most frequently used the CHNRI method (26%), followed by the Delphi method (24%), James Lind Alliance method (8%), the Combined Approach Matrix (CAM) method (2%) and the Essential National Health Research method (<1%). About 3% of studies reported no clear process and provided very little information on how priorities were set. A further 19% used a combination of expert panel interview and focus group discussion (“consultation process”) but provided few details, while a further 2% used approaches that were clearly described, but not established as a replicable method. Online surveys that were not accompanied by face–to–face meetings were used in 8% of studies, while 9% used a combination of literature review and questionnaire to scrutinise the research options for prioritization among the participating experts. Conclusion The number of priority setting exercises in health research published in PubMed–indexed journals is increasing, especially since 2010. These exercises are being conducted at a variety of levels, ranging from the global level to the level of an individual hospital. With the development of new tools and methods which have a well–defined structure – such as the CHNRI method, James Lind Alliance Method and Combined Approach Matrix – it is

  3. Method development for impurity profiling in SFC: The selection of a dissimilar set of stationary phases.

    PubMed

    Galea, Charlene; Mangelings, Debby; Heyden, Yvan Vander

    2015-01-01

    Supercritical fluid chromatography (SFC) is drawing considerable interest as separation technique in the pharmaceutical industry. The technique is already well established in chiral separations both analytically and on a preparative scale. The use of SFC as a technique for drug impurity profiling is examined here. To define starting conditions in method development for drug impurity profiling, a set of dissimilar stationary phases is screened in parallel. The possibility to select a set of dissimilar columns using the retention factors (k-values) for a set of 64 drugs measured on 27 columns in SFC was examined. Experiments were carried out at a back-pressure of 150 bar and 25 °C with a mobile phase consisting of CO2 and methanol with 0.1% isopropylamine (5-40% over 10 min) at a flow rate of 3 mL/min. These k-values were then used to calculate correlation coefficients on the one hand and to perform a principal component analysis on the other. The Kennard and Stone algorithm, besides dendrograms and correlation-coefficient colour maps were used to select a set of 6 dissimilar stationary phases. The stationary phase characterization results from this study were compared to those from previous studies found in the literature. Retention mechanisms for compounds possessing different properties were also evaluated. The dissimilarity of the selected subset of 6 stationary phases was validated using mixtures of compounds with similar properties and structures, as one can expect in a drug impurity profile. PMID:25630237

  4. Method development for impurity profiling in SFC: The selection of a dissimilar set of stationary phases.

    PubMed

    Galea, Charlene; Mangelings, Debby; Heyden, Yvan Vander

    2015-01-01

    Supercritical fluid chromatography (SFC) is drawing considerable interest as separation technique in the pharmaceutical industry. The technique is already well established in chiral separations both analytically and on a preparative scale. The use of SFC as a technique for drug impurity profiling is examined here. To define starting conditions in method development for drug impurity profiling, a set of dissimilar stationary phases is screened in parallel. The possibility to select a set of dissimilar columns using the retention factors (k-values) for a set of 64 drugs measured on 27 columns in SFC was examined. Experiments were carried out at a back-pressure of 150 bar and 25 °C with a mobile phase consisting of CO2 and methanol with 0.1% isopropylamine (5-40% over 10 min) at a flow rate of 3 mL/min. These k-values were then used to calculate correlation coefficients on the one hand and to perform a principal component analysis on the other. The Kennard and Stone algorithm, besides dendrograms and correlation-coefficient colour maps were used to select a set of 6 dissimilar stationary phases. The stationary phase characterization results from this study were compared to those from previous studies found in the literature. Retention mechanisms for compounds possessing different properties were also evaluated. The dissimilarity of the selected subset of 6 stationary phases was validated using mixtures of compounds with similar properties and structures, as one can expect in a drug impurity profile.

  5. Set-theoretic methods in robust detection and isolation of sensor faults

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Puig, Vicenç; Ocampo-Martinez, Carlos; Olaru, Sorin; Stoican, Florin

    2015-10-01

    This paper proposes a sensorfault detection and isolation (FDI) approach based on interval observers and invariant sets. In fault detection (FD), both interval observer-based and invariant set-based mechanisms are used to provide real-time fault alarms. In fault isolation (FI), the proposed approach also uses these two different mechanisms. The former, based on interval observers, aims to isolate faults during the transient-state operation induced by faults. If the former does not succeed, the latter, based on both interval observers and invariant sets, is started to guarantee FI after the system enters into steady state. Besides, a collection of invariant set-based FDI conditions are established by using all available system-operating information provided by all interval observers. In order to reduce computational complexity, a method to remove all available but redundant/unnecessary system-operating information is incorporated into this approach. If the considered faults satisfy the proposed FDI conditions, it can be guaranteed that they are detectable and isolable after their occurrences. This paper concludes with a case study based on a subsystem of a wind turbine benchmark, which can illustrate the effectiveness of this FDI technique.

  6. Some geometrical methods for constructing contradiction measures on Atanassov's intuitionistic fuzzy sets

    NASA Astrophysics Data System (ADS)

    Castiñeira, Elena E.; Torres-Blanc, Carmen; Cubillo, Susana

    2011-08-01

    Trillas et al. (1999, Soft computing, 3 (4), 197-199) and Trillas and Cubillo (1999, On non-contradictory input/output couples in Zadeh's CRI proceeding, 28-32) introduced the study of contradiction in the framework of fuzzy logic because of the significance of avoiding contradictory outputs in inference processes. Later, the study of contradiction in the framework of Atanassov's intuitionistic fuzzy sets (A-IFSs) was initiated by Cubillo and Castiñeira (2004, Contradiction in intuitionistic fuzzy sets proceeding, 2180-2186). The axiomatic definition of contradiction measure was stated in Castiñeira and Cubillo (2009, International journal of intelligent systems, 24, 863-888). Likewise, the concept of continuity of these measures was formalized through several axioms. To be precise, they defined continuity when the sets 'are increasing', denominated continuity from below, and continuity when the sets 'are decreasing', or continuity from above. The aim of this paper is to provide some geometrical construction methods for obtaining contradiction measures in the framework of A-IFSs and to study what continuity properties these measures satisfy. Furthermore, we show the geometrical interpretations motivating the measures.

  7. 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)

  8. Parallel level-set methods on adaptive tree-based grids

    NASA Astrophysics Data System (ADS)

    Mirzadeh, Mohammad; Guittet, Arthur; Burstedde, Carsten; Gibou, Frederic

    2016-10-01

    We present scalable algorithms for the level-set method on dynamic, adaptive Quadtree and Octree Cartesian grids. The algorithms are fully parallelized and implemented using the MPI standard and the open-source p4est library. We solve the level set equation with a semi-Lagrangian method which, similar to its serial implementation, is free of any time-step restrictions. This is achieved by introducing a scalable global interpolation scheme on adaptive tree-based grids. Moreover, we present a simple parallel reinitialization scheme using the pseudo-time transient formulation. Both parallel algorithms scale on the Stampede supercomputer, where we are currently using up to 4096 CPU cores, the limit of our current account. Finally, a relevant application of the algorithms is presented in modeling a crystallization phenomenon by solving a Stefan problem, illustrating a level of detail that would be impossible to achieve without a parallel adaptive strategy. We believe that the algorithms presented in this article will be of interest and useful to researchers working with the level-set framework and modeling multi-scale physics in general.

  9. A variational level set method for the topology optimization of steady-state Navier Stokes flow

    NASA Astrophysics Data System (ADS)

    Zhou, Shiwei; Li, Qing

    2008-12-01

    The smoothness of topological interfaces often largely affects the fluid optimization and sometimes makes the density-based approaches, though well established in structural designs, inadequate. This paper presents a level-set method for topology optimization of steady-state Navier-Stokes flow subject to a specific fluid volume constraint. The solid-fluid interface is implicitly characterized by a zero-level contour of a higher-order scalar level set function and can be naturally transformed to other configurations as its host moves. A variational form of the cost function is constructed based upon the adjoint variable and Lagrangian multiplier techniques. To satisfy the volume constraint effectively, the Lagrangian multiplier derived from the first-order approximation of the cost function is amended by the bisection algorithm. The procedure allows evolving initial design to an optimal shape and/or topology by solving the Hamilton-Jacobi equation. Two classes of benchmarking examples are presented in this paper: (1) periodic microstructural material design for the maximum permeability; and (2) topology optimization of flow channels for minimizing energy dissipation. A number of 2D and 3D examples well demonstrated the feasibility and advantage of the level-set method in solving fluid-solid shape and topology optimization problems.

  10. Tools for measuring patient safety in primary care settings using the RAND/UCLA appropriateness method

    PubMed Central

    2014-01-01

    Background The majority of patient contacts occur in general practice but general practice patient safety has been poorly described and under-researched to date compared to hospital settings. Our objective was to produce a set of patient safety tools and indicators that can be used in general practices in any healthcare setting and develop a ‘toolkit’ of feasible patient safety measures for general practices in England. Methods A RAND/UCLA Appropriateness Method exercise was conducted with a panel of international experts in general practice patient safety. Statements were developed from an extensive systematic literature review of patient safety in general practice. We used standard RAND/UCLA Appropriateness Method rating methods to identify necessary items for assessing patient safety in general practice, framed in terms of the Structure-Process-Outcome taxonomy. Items were included in the toolkit if they received an overall panel median score of ≥7 with agreement (no more than two panel members rating the statement outside a 3-point distribution around the median). Results Of 205 identified statements, the panel rated 101 as necessary for assessing the safety of general practices. Of these 101 statements, 73 covered structures or organisational issues, 22 addressed processes and 6 focused on outcomes. Conclusions We developed and tested tools that can lead to interventions to improve safety outcomes in general practice. This paper reports the first attempt to systematically develop a patient safety toolkit for general practice, which has the potential to improve safety, cost effectiveness and patient experience, in any healthcare system. PMID:24902490

  11. Unsaturated fractured rock characterization methods and data sets at the Apache Leap Tuff Site

    SciTech Connect

    Rasmussen, T.C.; Evans, D.D.; Sheets, P.J.; Blanford, J.H.

    1990-08-01

    Performance assessment of high-level nuclear waste containment feasibility requires representative values of parameters as input, including parameter moments, distributional characteristics, and covariance structures between parameters. To meet this need, characterization methods and data sets for interstitial, hydraulic, pneumatic and thermal parameters for a slightly welded fractured tuff at the Apache Leap Tuff Site situated in central Arizona are reported in this document. The data sets include the influence of matric suction on measured parameters. Spatial variability is investigated by sampling along nine boreholes at regular distances. Laboratory parameter estimates for 105 core segments are provided, as well as field estimates centered on the intervals where the core segments were collected. Measurement uncertainty is estimated by repetitively testing control samples. 31 refs., 10 figs., 21 tabs.

  12. Heuristic method for searches on large data-sets organised using network models

    NASA Astrophysics Data System (ADS)

    Ruiz-Fernández, D.; Quintana-Pacheco, Y.

    2016-05-01

    Searches on large data-sets have become an important issue in recent years. An alternative, which has achieved good results, is the use of methods relying on data mining techniques, such as cluster-based retrieval. This paper proposes a heuristic search that is based on an organisational model that reflects similarity relationships among data elements. The search is guided by using quality estimators of model nodes, which are obtained by the progressive evaluation of the given target function for the elements associated with each node. The results of the experiments confirm the effectiveness of the proposed algorithm. High-quality solutions are obtained evaluating a relatively small percentage of elements in the data-sets.

  13. Improved semen collection method for wild felids: urethral catheterization yields high sperm quality in African lions (Panthera leo).

    PubMed

    Lueders, I; Luther, I; Scheepers, G; van der Horst, G

    2012-08-01

    For wild and domestic felids, electroejaculation (EE) is the most common semen collection method. However, the equipment is expensive, there is a risk of urine contamination and animals usually show strong muscular contraction despite general anesthesia. Accordingly, we tested the feasibility of a different approach using urethral catheterization (UC) in seven African lions, previously described for domestic cats only. After general anesthesia with the α2-agonist medetomidine (which also stimulates semen release into the urethra) and ketamine, a transrectal ultrasound was performed to locate the prostate. A commercial dog urinary catheter (2.6 or 3.3 mm in diameter) was advanced approximately 30 cm into the urethra to allow semen collection into the lumen of the catheter by capillary forces. After retraction, sperm volumes between of 422.86 ± 296.07 μl yielded motility of 88.83 ± 13.27% (mean ± SD) with a mean sperm concentration of 1.94 × 10(9)/ml. Here we describe a simple, field friendly and effective method to attain highly concentrated semen samples with excellent motility in lions and potentially other wild felid species as an alternative to electroejaculation. PMID:22538007

  14. Improved semen collection method for wild felids: urethral catheterization yields high sperm quality in African lions (Panthera leo).

    PubMed

    Lueders, I; Luther, I; Scheepers, G; van der Horst, G

    2012-08-01

    For wild and domestic felids, electroejaculation (EE) is the most common semen collection method. However, the equipment is expensive, there is a risk of urine contamination and animals usually show strong muscular contraction despite general anesthesia. Accordingly, we tested the feasibility of a different approach using urethral catheterization (UC) in seven African lions, previously described for domestic cats only. After general anesthesia with the α2-agonist medetomidine (which also stimulates semen release into the urethra) and ketamine, a transrectal ultrasound was performed to locate the prostate. A commercial dog urinary catheter (2.6 or 3.3 mm in diameter) was advanced approximately 30 cm into the urethra to allow semen collection into the lumen of the catheter by capillary forces. After retraction, sperm volumes between of 422.86 ± 296.07 μl yielded motility of 88.83 ± 13.27% (mean ± SD) with a mean sperm concentration of 1.94 × 10(9)/ml. Here we describe a simple, field friendly and effective method to attain highly concentrated semen samples with excellent motility in lions and potentially other wild felid species as an alternative to electroejaculation.

  15. 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…

  16. A method of setting limits for the purpose of quality assurance

    NASA Astrophysics Data System (ADS)

    Sanghangthum, Taweap; Suriyapee, Sivalee; Kim, Gwe-Ya; Pawlicki, Todd

    2013-10-01

    The result from any assurance measurement needs to be checked against some limits for acceptability. There are two types of limits; those that define clinical acceptability (action limits) and those that are meant to serve as a warning that the measurement is close to the action limits (tolerance limits). Currently, there is no standard procedure to set these limits. In this work, we propose an operational procedure to set tolerance limits and action limits. The approach to establish the limits is based on techniques of quality engineering using control charts and a process capability index. The method is different for tolerance limits and action limits with action limits being categorized into those that are specified and unspecified. The procedure is to first ensure process control using the I-MR control charts. Then, the tolerance limits are set equal to the control chart limits on the I chart. Action limits are determined using the Cpm process capability index with the requirements that the process must be in-control. The limits from the proposed procedure are compared to an existing or conventional method. Four examples are investigated: two of volumetric modulated arc therapy (VMAT) point dose quality assurance (QA) and two of routine linear accelerator output QA. The tolerance limits range from about 6% larger to 9% smaller than conventional action limits for VMAT QA cases. For the linac output QA, tolerance limits are about 60% smaller than conventional action limits. The operational procedure describe in this work is based on established quality management tools and will provide a systematic guide to set up tolerance and action limits for different equipment and processes.

  17. Method for automatically identifying spectra of different wood cell wall layers in Raman imaging data set.

    PubMed

    Zhang, Xun; Ji, Zhe; Zhou, Xia; Ma, Jian-Feng; Hu, Ya-Hong; Xu, Feng

    2015-01-20

    The technique of Raman spectroscopic imaging is finding ever-increasing applications in the field of wood science for its ability to provide spatial and spectral information about the sample. On the basis of the acquired Raman imaging data set, it is possible to determine the distribution of chemical components in various wood cell wall layers. However, the Raman imaging data set often contains thousands of spectra measured at hundreds or even thousands of individual frequencies, which results in difficulties accurately and quickly extracting all of the spectra within a specific morphological region of wood cell walls. To address this issue, the authors propose a new method to automatically identify Raman spectra of different cell wall layers on the basis of principal component analysis (PCA) and cluster analysis. A Raman imaging data set collected from a 55.5 μm × 47.5 μm cross-section of poplar tension wood was analyzed. Several thousand spectra were successfully classified into five groups in accordance with different morphological regions, namely, cell corner (CC), compound middle lamella (CML), secondary wall (SW), gelatinous layer (G-layer), and cell lumen. Their corresponding average spectra were also calculated. In addition, the relationship between different characteristic peaks in the obtained Raman spectra was estimated and it was found that the peak at 1331 cm(-1) is more related to lignin rather than cellulose. Not only can this novel method provide a convenient and accurate procedure for identifying the spectra of different cell wall layers in a Raman imaging data set, but it also can bring new insights into studying the morphology and topochemistry in wood cell walls.

  18. An automatic fractional coefficient setting method of FODPSO for hyperspectral image segmentation

    NASA Astrophysics Data System (ADS)

    Xie, Weiying; Li, Yunsong

    2015-05-01

    In this paper, an automatic fractional coefficient setting method of fractional-order Darwinian particle swarm optimization (FODPSO) is proposed for hyperspectral image segmentation. The spectrum has been already taken into consideration by integrating various types of band selection algorithms, firstly. We provide a short overview of the hyperspectral image to select an appropriate set of bands by combining supervised, semi-supervised and unsupervised band selection algorithms. Some approaches are not limited in regards to their spectral dimension, but are limited with respect to their spatial dimension owing to low spatial resolution. The addition of spatial information will be focused on improving the performance of hyperspectral image segmentation for later fusion or classification. Many researchers have advocated that a large fractional coefficient should be in the exploration state while a small fractional coefficient should be in the exploitation, which does not mean the coefficient purely decrease with time. Due to such reasons, we propose an adaptive FODPSO by setting the fractional coefficient adaptively for the application of final hyperspectral image segmentation. In fact, the paper introduces an evolutionary factor to automatically control the fractional coefficient by using a sigmoid function. Therefore, fractional coefficient with large value will benefit the global search in the exploration state. Conversely, when the fractional coefficient has a small value, the exploitation state is detected. Hence, it can avoid optimization process get trapped into the local optima. Ultimately, the experimental segmentation results prove the validity and efficiency of our proposed automatic fractional coefficient setting method of FODPSO compared with traditional PSO, DPSO and FODPSO.

  19. Wave breaking over sloping beaches using a coupled boundary integral-level set method

    SciTech Connect

    Garzon, M.; Adalsteinsson, D.; Gray, L.; Sethian, J.A.

    2003-12-08

    We present a numerical method for tracking breaking waves over sloping beaches. We use a fully non-linear potential model for in-compressible, irrotational and inviscid flow, and consider the effects of beach topography on breaking waves. The algorithm uses a Boundary Element Method (BEM) to compute the velocity at the interface, coupled to a Narrow Band Level Set Method to track the evolving air/water interface, and an associated extension equation to update the velocity potential both on and off the interface. The formulation of the algorithm is applicable to two and three dimensional breaking waves; in this paper, we concentrate on two-dimensional results showing wave breaking and rollup, and perform numerical convergence studies and comparison with previous techniques.

  20. Methods for Adjusting U.S. Geological Survey Rural Regression Peak Discharges in an Urban Setting

    USGS Publications Warehouse

    Moglen, Glenn E.; Shivers, Dorianne E.

    2006-01-01

    A study was conducted of 78 U.S. Geological Survey gaged streams that have been subjected to varying degrees of urbanization over the last three decades. Flood-frequency analysis coupled with nonlinear regression techniques were used to generate a set of equations for converting peak discharge estimates determined from rural regression equations to a set of peak discharge estimates that represent known urbanization. Specifically, urban regression equations for the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year return periods were calibrated as a function of the corresponding rural peak discharge and the percentage of impervious area in a watershed. The results of this study indicate that two sets of equations, one set based on imperviousness and one set based on population density, performed well. Both sets of equations are dependent on rural peak discharges, a measure of development (average percentage of imperviousness or average population density), and a measure of homogeneity of development within a watershed. Average imperviousness was readily determined by using geographic information system methods and commonly available land-cover data. Similarly, average population density was easily determined from census data. Thus, a key advantage to the equations developed in this study is that they do not require field measurements of watershed characteristics as did the U.S. Geological Survey urban equations developed in an earlier investigation. During this study, the U.S. Geological Survey PeakFQ program was used as an integral tool in the calibration of all equations. The scarcity of historical land-use data, however, made exclusive use of flow records necessary for the 30-year period from 1970 to 2000. Such relatively short-duration streamflow time series required a nonstandard treatment of the historical data function of the PeakFQ program in comparison to published guidelines. Thus, the approach used during this investigation does not fully comply with the

  1. Methods for comparing nutrients in beebread made by Africanized and European honey bees and the effects on hemolymph protein titers.

    PubMed

    Degrandi-Hoffman, Gloria; Eckholm, Bruce; Huang, Ming

    2015-03-17

    Honey bees obtain nutrients from pollen they collect and store in the hive as beebread. We developed methods to control the pollen source that bees collect and convert to beebread by placing colonies in a specially constructed enclosed flight area. Methods were developed to analyze the protein and amino acid composition of the pollen and beebread. We also describe how consumption of the beebread was measured and methods used to determine adult worker bee hemolymph protein titers after feeding on beebread for 4, 7 and 11 days after emergence. Methods were applied to determine if genotype affects the conversion of pollen to beebread and the rate that bees consume and acquire protein from it. Two subspecies (European and Africanized honey bees; EHB and AHB respectively) were provided with the same pollen source. Based on the developed methods, beebread made by both subspecies had lower protein concentrations and pH values than the pollen. In general, amino acid concentrations in beebread made by either EHB or AHB were similar and occurred at higher levels in beebread than in pollen. Both AHB and EHB consumed significantly more of the beebread made by AHB than by EHB. Though EHB and AHB consumed similar amounts of each type of beebread, hemolymph protein concentrations in AHB were higher than in EHB. Differences in protein acquisition between AHB and EHB might reflect environmental adaptations related to the geographic region where each subspecies evolved. These differences could contribute to the successful establishment of AHB populations in the New World because of the effects on brood rearing and colony growth.

  2. Methods for Comparing Nutrients in Beebread Made by Africanized and European Honey Bees and the Effects on Hemolymph Protein Titers

    PubMed Central

    Degrandi-Hoffman, Gloria; Eckholm, Bruce; Huang, Ming

    2015-01-01

    Honey bees obtain nutrients from pollen they collect and store in the hive as beebread. We developed methods to control the pollen source that bees collect and convert to beebread by placing colonies in a specially constructed enclosed flight area. Methods were developed to analyze the protein and amino acid composition of the pollen and beebread. We also describe how consumption of the beebread was measured and methods used to determine adult worker bee hemolymph protein titers after feeding on beebread for 4, 7 and 11 days after emergence. Methods were applied to determine if genotype affects the conversion of pollen to beebread and the rate that bees consume and acquire protein from it. Two subspecies (European and Africanized honey bees; EHB and AHB respectively) were provided with the same pollen source. Based on the developed methods, beebread made by both subspecies had lower protein concentrations and pH values than the pollen. In general, amino acid concentrations in beebread made by either EHB or AHB were similar and occurred at higher levels in beebread than in pollen. Both AHB and EHB consumed significantly more of the beebread made by AHB than by EHB. Though EHB and AHB consumed similar amounts of each type of beebread, hemolymph protein concentrations in AHB were higher than in EHB. Differences in protein acquisition between AHB and EHB might reflect environmental adaptations related to the geographic region where each subspecies evolved. These differences could contribute to the successful establishment of AHB populations in the New World because of the effects on brood rearing and colony growth. PMID:25867246

  3. Spatial and Temporal Evolution of Eruptive Activity in a Youthful Extensional Setting: the Case of the Nyamulagira Volcanic Field, Western Branch of the East African Rift

    NASA Astrophysics Data System (ADS)

    Smets, B.; Kervyn, M.; d'Oreye, N.; Kervyn, F.

    2014-12-01

    Nyamulagira is the westernmost volcano of the Virunga volcanic province, in the western branch of the East African Rift. This shield volcano is one of the most active African volcanoes with one eruption every 1-4 year(s). Nyamulagira's eruptions usually occur along the flanks of the main edifice and in the lava plain, producing pyroclastic cone(s) and 10-20 km-long lava flows. Between 1913 and 1938, the activity was however restricted to the summit caldera, where lava fountains progressively gave birth to a lava lake, which disappeared in 1938 during the partial collapse of the summit caldera and the onset of a 2.5 years-long flank eruption. The location of flank eruptions and the orientation of the eruptive fissures are strongly influenced by the edifice loading, and by the NNW-SSE fracture network that crosses the main edifice and link it to the neighboring Nyiragongo volcano. But rift fault can also influence fissure orientations and cone alignments, especially for distal events. The flank eruptions typically have similar characteristics, lasting few days to few weeks, with an average of 20-30 days. Less frequently, flank eruptions can be larger and more complex, lasting several months and/or emitting much larger volumes of lava. By combining historical and recent observations, we suggest that magma overpressure at shallow depth is the main cause of flank events. Major eruptions seem to be related to a deeper source able to trigger large magma injections through deep structures, such as rift faults. Since April 2012, the activity of Nyamulagira is restricted to the summit caldera, with continuous and intense gas emissions and, since mid-2014, by lava fountains. This change in eruptive behavior, if it persists, may leads to the emergence of a new lava lake and may significantly decreases the frequency of flank events

  4. Improved methods for calculating the multifractal spectrum for small data sets

    NASA Astrophysics Data System (ADS)

    Anderson, Leif

    There are multiple definitions for fractal dimension, and those definitions disagree. The multifractal spectrum provides a unifying framework for a broad family of definitions of dimension, but it requires large amounts of data to compute. We provide a description of the multifractal spectrum, one existing improvement that improves convergence for small data sets: the Extended Box Algorithm (EBA), and develop several further improvements: Local and Global Norm modifications to the EBA, the a-Norm, the Variable Box size Algorithm (VBA), and the Patchwork method.

  5. Methods for Identifying Neisseria meningitidis Carriers: A Multi-Center Study in the African Meningitis Belt

    PubMed Central

    Basta, Nicole E.; Stuart, James M.; Nascimento, Maria C.; Manigart, Olivier; Trotter, Caroline; Hassan-King, Musa; Chandramohan, Daniel; Sow, Samba O.; Berthe, Abdoulaye; Bedru, Ahmed; Tekletsion, Yenenesh K.; Collard, Jean-Marc; Jusot, Jean-François; Diallo, Aldiouma; Basséne, Hubert; Daugla, Doumagoum M.; Gamougam, Khadidja; Hodgson, Abraham; Forgor, Abudulai A.; Omotara, Babatunji A.; Gadzama, Galadima B.; Watkins, Eleanor R.; Rebbetts, Lisa S.; Diallo, Kanny; Weiss, Noel S.; Halloran, M. Elizabeth; Maiden, Martin C. J.; Greenwood, Brian

    2013-01-01

    Objective Detection of meningococcal carriers is key to understanding the epidemiology of Neisseria meningitidis, yet no gold standard has been established. Here, we directly compare two methods for collecting pharyngeal swabs to identify meningococcal carriers. Methods We conducted cross-sectional surveys of schoolchildren at multiple sites in Africa to compare swabbing the posterior pharynx behind the uvula (U) to swabbing the posterior pharynx behind the uvula plus one tonsil (T). Swabs were cultured immediately and analyzed using molecular methods. Results One thousand and six paired swab samples collected from schoolchildren in four countries were analyzed. Prevalence of meningococcal carriage was 6.9% (95% CI: 5.4-8.6%) based on the results from both swabs, but the observed prevalence was lower based on one swab type alone. Prevalence based on the T swab or the U swab alone was similar (5.2% (95% CI: 3.8-6.7%) versus 4.9% (95% CI: 3.6-6.4%) respectively (p=0.6)). The concordance between the two methods was 96.3% and the kappa was 0.61 (95% CI: 0.50-0.73), indicating good agreement. Conclusions These two commonly used methods for collecting pharyngeal swabs provide consistent estimates of the prevalence of carriage, but both methods misclassified carriers to some degree, leading to underestimates of the prevalence. PMID:24194921

  6. Numerical Simulation of Dynamic Contact Angles and Contact Lines in Multiphase Flows using Level Set Method

    NASA Astrophysics Data System (ADS)

    Pendota, Premchand

    Many physical phenomena and industrial applications involve multiphase fluid flows and hence it is of high importance to be able to simulate various aspects of these flows accurately. The Dynamic Contact Angles (DCA) and the contact lines at the wall boundaries are a couple of such important aspects. In the past few decades, many mathematical models were developed for predicting the contact angles of the inter-face with the wall boundary under various flow conditions. These models are used to incorporate the physics of DCA and contact line motion in numerical simulations using various interface capturing/tracking techniques. In the current thesis, a simple approach to incorporate the static and dynamic contact angle boundary conditions using the level set method is developed and implemented in multiphase CFD codes, LIT (Level set Interface Tracking) (Herrmann (2008)) and NGA (flow solver) (Desjardins et al (2008)). Various DCA models and associated boundary conditions are reviewed. In addition, numerical aspects such as the occurrence of a stress singularity at the contact lines and grid convergence of macroscopic interface shape are dealt with in the context of the level set approach.

  7. Some free boundary problems in potential flow regime usinga based level set method

    SciTech Connect

    Garzon, M.; Bobillo-Ares, N.; Sethian, J.A.

    2008-12-09

    Recent advances in the field of fluid mechanics with moving fronts are linked to the use of Level Set Methods, a versatile mathematical technique to follow free boundaries which undergo topological changes. A challenging class of problems in this context are those related to the solution of a partial differential equation posed on a moving domain, in which the boundary condition for the PDE solver has to be obtained from a partial differential equation defined on the front. This is the case of potential flow models with moving boundaries. Moreover the fluid front will possibly be carrying some material substance which will diffuse in the front and be advected by the front velocity, as for example the use of surfactants to lower surface tension. We present a Level Set based methodology to embed this partial differential equations defined on the front in a complete Eulerian framework, fully avoiding the tracking of fluid particles and its known limitations. To show the advantages of this approach in the field of Fluid Mechanics we present in this work one particular application: the numerical approximation of a potential flow model to simulate the evolution and breaking of a solitary wave propagating over a slopping bottom and compare the level set based algorithm with previous front tracking models.

  8. Use of handheld X-ray fluorescence as a non-invasive method to distinguish between Asian and African elephant tusks.

    PubMed

    Buddhachat, Kittisak; Thitaram, Chatchote; Brown, Janine L; Klinhom, Sarisa; Bansiddhi, Pakkanut; Penchart, Kitichaya; Ouitavon, Kanita; Sriaksorn, Khanittha; Pa-in, Chalermpol; Kanchanasaka, Budsabong; Somgird, Chaleamchat; Nganvongpanit, Korakot

    2016-01-01

    We describe the use of handheld X-ray fluorescence, for elephant tusk species identification. Asian (n = 72) and African (n = 85) elephant tusks were scanned and we utilized the species differences in elemental composition to develop a functional model differentiating between species with high precision. Spatially, the majority of measured elements (n = 26) exhibited a homogeneous distribution in cross-section, but a more heterologous pattern in the longitudinal direction. Twenty-one of twenty four elements differed between Asian and African samples. Data were subjected to hierarchical cluster analysis followed by a stepwise discriminant analysis, which identified elements for the functional equation. The best equation consisted of ratios of Si, S, Cl, Ti, Mn, Ag, Sb and W, with Zr as the denominator. Next, Bayesian binary regression model analysis was conducted to predict the probability that a tusk would be of African origin. A cut-off value was established to improve discrimination. This Bayesian hybrid classification model was then validated by scanning an additional 30 Asian and 41 African tusks, which showed high accuracy (94%) and precision (95%) rates. We conclude that handheld XRF is an accurate, non-invasive method to discriminate origin of elephant tusks provides rapid results applicable to use in the field.

  9. Use of handheld X-ray fluorescence as a non-invasive method to distinguish between Asian and African elephant tusks

    PubMed Central

    Buddhachat, Kittisak; Thitaram, Chatchote; Brown, Janine L.; Klinhom, Sarisa; Bansiddhi, Pakkanut; Penchart, Kitichaya; Ouitavon, Kanita; Sriaksorn, Khanittha; Pa-in, Chalermpol; Kanchanasaka, Budsabong; Somgird, Chaleamchat; Nganvongpanit, Korakot

    2016-01-01

    We describe the use of handheld X-ray fluorescence, for elephant tusk species identification. Asian (n = 72) and African (n = 85) elephant tusks were scanned and we utilized the species differences in elemental composition to develop a functional model differentiating between species with high precision. Spatially, the majority of measured elements (n = 26) exhibited a homogeneous distribution in cross-section, but a more heterologous pattern in the longitudinal direction. Twenty-one of twenty four elements differed between Asian and African samples. Data were subjected to hierarchical cluster analysis followed by a stepwise discriminant analysis, which identified elements for the functional equation. The best equation consisted of ratios of Si, S, Cl, Ti, Mn, Ag, Sb and W, with Zr as the denominator. Next, Bayesian binary regression model analysis was conducted to predict the probability that a tusk would be of African origin. A cut-off value was established to improve discrimination. This Bayesian hybrid classification model was then validated by scanning an additional 30 Asian and 41 African tusks, which showed high accuracy (94%) and precision (95%) rates. We conclude that handheld XRF is an accurate, non-invasive method to discriminate origin of elephant tusks provides rapid results applicable to use in the field. PMID:27097717

  10. Use of handheld X-ray fluorescence as a non-invasive method to distinguish between Asian and African elephant tusks.

    PubMed

    Buddhachat, Kittisak; Thitaram, Chatchote; Brown, Janine L; Klinhom, Sarisa; Bansiddhi, Pakkanut; Penchart, Kitichaya; Ouitavon, Kanita; Sriaksorn, Khanittha; Pa-in, Chalermpol; Kanchanasaka, Budsabong; Somgird, Chaleamchat; Nganvongpanit, Korakot

    2016-01-01

    We describe the use of handheld X-ray fluorescence, for elephant tusk species identification. Asian (n = 72) and African (n = 85) elephant tusks were scanned and we utilized the species differences in elemental composition to develop a functional model differentiating between species with high precision. Spatially, the majority of measured elements (n = 26) exhibited a homogeneous distribution in cross-section, but a more heterologous pattern in the longitudinal direction. Twenty-one of twenty four elements differed between Asian and African samples. Data were subjected to hierarchical cluster analysis followed by a stepwise discriminant analysis, which identified elements for the functional equation. The best equation consisted of ratios of Si, S, Cl, Ti, Mn, Ag, Sb and W, with Zr as the denominator. Next, Bayesian binary regression model analysis was conducted to predict the probability that a tusk would be of African origin. A cut-off value was established to improve discrimination. This Bayesian hybrid classification model was then validated by scanning an additional 30 Asian and 41 African tusks, which showed high accuracy (94%) and precision (95%) rates. We conclude that handheld XRF is an accurate, non-invasive method to discriminate origin of elephant tusks provides rapid results applicable to use in the field. PMID:27097717

  11. Marker ReDistancing/Level Set Method for High-Fidelity Implicit Interface Tracking

    SciTech Connect

    Robert Nourgaliev; Samet Kadioglu; Vincent Mousseau; Dana Knoll

    2010-02-01

    A hybrid of the Front-Tracking (FT) and the Level-Set (LS) methods is introduced, combining advantages and removing drawbacks of both methods. The kinematics of the interface is treated in a Lagrangian (FT) manner, by tracking markers placed at the interface. The markers are not connected – instead, the interface topology is resolved in an Eulerian (LS) framework, by wrapping a signed distance function around Lagrangian markers each time the markers move. For accuracy and efficiency, we have developed a high-order “anchoring” algorithm and an implicit PDE-based re-distancing. We have demonstrated that the method is 3rd-order accurate in space, near the markers, and therefore 1st-order convergent in curvature; in contrast to traditional PDE-based re-initialization algorithms, which tend to slightly relocate the zero Level Set and can be shown to be non-convergent in curvature. The implicit pseudo-time discretization of the re-distancing equation is implemented within the Jacobian-Free Newton Krylov (JFNK) framework combined with ILU(k) preconditioning. We have demonstrated that the steady-state solutions in pseudo-time can be achieved very efficiently, with iterations (CFL ), in contrast to the explicit re-distancing which requires 100s of iterations with CFL . The most cost-effective algorithm is found to be a hybrid of explicit and implicit discretizations, in which we apply first 10-15 iterations with explicit discretization (to bring the initial guess to the ball of convergence for the Newton’s method) and then finishing with 2-3 implicit steps, bringing the re-distancing equation to a complete steady-state. The eigenscopy of the JFNK-ILU(k) demonstrates the efficiency of the ILU(k) preconditioner, which effectively cluster eigenvalues of the otherwise extremely ill-conditioned Jacobian matrices, thereby enabling the Krylov (GMRES) method to converge with iterations, with only a few levels of ILU fill-ins. Importantly, due to the Level Set localization

  12. Automated Robust Image Segmentation: Level Set Method Using Nonnegative Matrix Factorization with Application to Brain MRI.

    PubMed

    Dera, Dimah; Bouaynaya, Nidhal; Fathallah-Shaykh, Hassan M

    2016-07-01

    We address the problem of fully automated region discovery and robust image segmentation by devising a new deformable model based on the level set method (LSM) and the probabilistic nonnegative matrix factorization (NMF). We describe the use of NMF to calculate the number of distinct regions in the image and to derive the local distribution of the regions, which is incorporated into the energy functional of the LSM. The results demonstrate that our NMF-LSM method is superior to other approaches when applied to synthetic binary and gray-scale images and to clinical magnetic resonance images (MRI) of the human brain with and without a malignant brain tumor, glioblastoma multiforme. In particular, the NMF-LSM method is fully automated, highly accurate, less sensitive to the initial selection of the contour(s) or initial conditions, more robust to noise and model parameters, and able to detect as small distinct regions as desired. These advantages stem from the fact that the proposed method relies on histogram information instead of intensity values and does not introduce nuisance model parameters. These properties provide a general approach for automated robust region discovery and segmentation in heterogeneous images. Compared with the retrospective radiological diagnoses of two patients with non-enhancing grade 2 and 3 oligodendroglioma, the NMF-LSM detects earlier progression times and appears suitable for monitoring tumor response. The NMF-LSM method fills an important need of automated segmentation of clinical MRI. PMID:27417984

  13. Setting health priorities in a Swiss canton: what do different methods tell us?

    PubMed Central

    Schopper, D.; Torres, A. M.; Pereira, J.; Ammon, C.; Cuende, N.; Alonso, M.; Baylin, A.; Ronchi, A.; Rougemont, A.

    2000-01-01

    STUDY OBJECTIVE—Despite excellent mortality indicators, there is clear evidence that the health status of the population of Geneva could be improved if more attention and resources were devoted to prevention strategies. To identify a set of robust health priorities an original approach was used triangulating results between three methods.
METHODS—The study calculated potential years of life lost, disability adjusted years of life lost, and conducted a Delphi survey to gather the opinion of health professionals and the general public.
MAIN RESULTS—Several health conditions were unanimously selected by all three methods as top priorities: cardiovascular diseases, AIDS, respiratory cancer, breast cancer for women, suicide and traffic accidents. In addition, two determinants—alcohol abuse and tobacco abuse—for which a clear conceptual link could be established between all methods were chosen. Connections between priorities identified through the DALY and the Delphi method lead to further inclusion of chronic back pain and depression. Some issues solely identified through the Delphi survey were included as they were consistently considered important by professionals and the lay public alike—violence in the family, unemployment, social exclusion.
CONCLUSIONS—These results indicate that health priorities, and by extension health care priorities, would benefit from using a mix of quantitative and qualitative research methods. The triangulation of results allows for a broader perspective and makes results more acceptable.


Keywords: health priorities; DALYs; Delphi survey PMID:10814661

  14. A GPU-accelerated adaptive discontinuous Galerkin method for level set equation

    NASA Astrophysics Data System (ADS)

    Karakus, A.; Warburton, T.; Aksel, M. H.; Sert, C.

    2016-01-01

    This paper presents a GPU-accelerated nodal discontinuous Galerkin method for the solution of two- and three-dimensional level set (LS) equation on unstructured adaptive meshes. Using adaptive mesh refinement, computations are localised mostly near the interface location to reduce the computational cost. Small global time step size resulting from the local adaptivity is avoided by local time-stepping based on a multi-rate Adams-Bashforth scheme. Platform independence of the solver is achieved with an extensible multi-threading programming API that allows runtime selection of different computing devices (GPU and CPU) and different threading interfaces (CUDA, OpenCL and OpenMP). Overall, a highly scalable, accurate and mass conservative numerical scheme that preserves the simplicity of LS formulation is obtained. Efficiency, performance and local high-order accuracy of the method are demonstrated through distinct numerical test cases.

  15. Vessel Segmentation and Blood Flow Simulation Using Level-Sets and Embedded Boundary Methods

    SciTech Connect

    Deschamps, T; Schwartz, P; Trebotich, D; Colella, P; Saloner, D; Malladi, R

    2004-12-09

    In this article we address the problem of blood flow simulation in realistic vascular objects. The anatomical surfaces are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of pathological objects such as aneurysms and stenoses. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier-Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element gridding of the whole volume, our method directly simulates the blood-flow inside the extracted surface without losing any complicated details and without building additional grids.

  16. Validation of non-rigid point-set registration methods using a porcine bladder pelvic phantom

    NASA Astrophysics Data System (ADS)

    Zakariaee, Roja; Hamarneh, Ghassan; Brown, Colin J.; Spadinger, Ingrid

    2016-01-01

    The problem of accurate dose accumulation in fractionated radiotherapy treatment for highly deformable organs, such as bladder, has garnered increasing interest over the past few years. However, more research is required in order to find a robust and efficient solution and to increase the accuracy over the current methods. The purpose of this study was to evaluate the feasibility and accuracy of utilizing non-rigid (affine or deformable) point-set registration in accumulating dose in bladder of different sizes and shapes. A pelvic phantom was built to house an ex vivo porcine bladder with fiducial landmarks adhered onto its surface. Four different volume fillings of the bladder were used (90, 180, 360 and 480 cc). The performance of MATLAB implementations of five different methods were compared, in aligning the bladder contour point-sets. The approaches evaluated were coherent point drift (CPD), gaussian mixture model, shape context, thin-plate spline robust point matching (TPS-RPM) and finite iterative closest point (ICP-finite). The evaluation metrics included registration runtime, target registration error (TRE), root-mean-square error (RMS) and Hausdorff distance (HD). The reference (source) dataset was alternated through all four points-sets, in order to study the effect of reference volume on the registration outcomes. While all deformable algorithms provided reasonable registration results, CPD provided the best TRE values (6.4 mm), and TPS-RPM yielded the best mean RMS and HD values (1.4 and 6.8 mm, respectively). ICP-finite was the fastest technique and TPS-RPM, the slowest.

  17. A flexible method for estimating the fraction of fitness influencing mutations from large sequencing data sets.

    PubMed

    Moon, Sunjin; Akey, Joshua M

    2016-06-01

    A continuing challenge in the analysis of massively large sequencing data sets is quantifying and interpreting non-neutrally evolving mutations. Here, we describe a flexible and robust approach based on the site frequency spectrum to estimate the fraction of deleterious and adaptive variants from large-scale sequencing data sets. We applied our method to approximately 1 million single nucleotide variants (SNVs) identified in high-coverage exome sequences of 6515 individuals. We estimate that the fraction of deleterious nonsynonymous SNVs is higher than previously reported; quantify the effects of genomic context, codon bias, chromatin accessibility, and number of protein-protein interactions on deleterious protein-coding SNVs; and identify pathways and networks that have likely been influenced by positive selection. Furthermore, we show that the fraction of deleterious nonsynonymous SNVs is significantly higher for Mendelian versus complex disease loci and in exons harboring dominant versus recessive Mendelian mutations. In summary, as genome-scale sequencing data accumulate in progressively larger sample sizes, our method will enable increasingly high-resolution inferences into the characteristics and determinants of non-neutral variation.

  18. A level set method for determining critical curvatures for drainage and imbibition.

    PubMed

    Prodanović, Masa; Bryant, Steven L

    2006-12-15

    An accurate description of the mechanics of pore level displacement of immiscible fluids could significantly improve the predictions from pore network models of capillary pressure-saturation curves, interfacial areas and relative permeability in real porous media. If we assume quasi-static displacement, at constant pressure and surface tension, pore scale interfaces are modeled as constant mean curvature surfaces, which are not easy to calculate. Moreover, the extremely irregular geometry of natural porous media makes it difficult to evaluate surface curvature values and corresponding geometric configurations of two fluids. Finally, accounting for the topological changes of the interface, such as splitting or merging, is nontrivial. We apply the level set method for tracking and propagating interfaces in order to robustly handle topological changes and to obtain geometrically correct interfaces. We describe a simple but robust model for determining critical curvatures for throat drainage and pore imbibition. The model is set up for quasi-static displacements but it nevertheless captures both reversible and irreversible behavior (Haines jump, pore body imbibition). The pore scale grain boundary conditions are extracted from model porous media and from imaged geometries in real rocks. The method gives quantitative agreement with measurements and with other theories and computational approaches. PMID:17027812

  19. GPU-Based Visualization of 3D Fluid Interfaces using Level Set Methods

    NASA Astrophysics Data System (ADS)

    Kadlec, B. J.

    2009-12-01

    We model a simple 3D fluid-interface problem using the level set method and visualize the interface as a dynamic surface. Level set methods allow implicit handling of complex topologies deformed by evolutions where sharp changes and cusps are present without destroying the representation. We present a highly optimized visualization and computation algorithm that is implemented in CUDA to run on the NVIDIA GeForce 295 GTX. CUDA is a general purpose parallel computing architecture that allows the NVIDIA GPU to be treated like a data parallel supercomputer in order to solve many computational problems in a fraction of the time required on a CPU. CUDA is compared to the new OpenCL™ (Open Computing Language), which is designed to run on heterogeneous computing environments but does not take advantage of low-level features in NVIDIA hardware that provide significant speedups. Therefore, our technique is implemented using CUDA and results are compared to a single CPU implementation to show the benefits of using the GPU and CUDA for visualizing fluid-interface problems. We solve a 1024^3 problem and experience significant speedup using the NVIDIA GeForce 295 GTX. Implementation details for mapping the problem to the GPU architecture are described as well as discussion on porting the technique to heterogeneous devices (AMD, Intel, IBM) using OpenCL. The results present a new interactive system for computing and visualizing the evolution of fluid interface problems on the GPU.

  20. Incorporating level set methods in Geographical Information Systems (GIS) for land-surface process modeling

    NASA Astrophysics Data System (ADS)

    Pullar, D.

    2005-08-01

    Land-surface processes include a broad class of models that operate at a landscape scale. Current modelling approaches tend to be specialised towards one type of process, yet it is the interaction of processes that is increasing seen as important to obtain a more integrated approach to land management. This paper presents a technique and a tool that may be applied generically to landscape processes. The technique tracks moving interfaces across landscapes for processes such as water flow, biochemical diffusion, and plant dispersal. Its theoretical development applies a Lagrangian approach to motion over a Eulerian grid space by tracking quantities across a landscape as an evolving front. An algorithm for this technique, called level set method, is implemented in a geographical information system (GIS). It fits with a field data model in GIS and is implemented as operators in map algebra. The paper describes an implementation of the level set methods in a map algebra programming language, called MapScript, and gives example program scripts for applications in ecology and hydrology.

  1. Preliminary studies developing methods for the control of Chrysomya putoria, the African latrine fly, in pit latrines in The Gambia

    PubMed Central

    Lindsay, T C; Jawara, M; D'Alessandro, U; Pinder, M; Lindsay, S W

    2013-01-01

    Objective To explore ways of controlling Chrysomya putoria, the African latrine fly, in pit latrines. As pit latrines are a major source of these flies, eliminating these important breeding sites is likely to reduce village fly populations, and may reduce the spread of diarrhoeal pathogens. Methods We treated 24 latrines in a Gambian village: six each with (i) pyriproxyfen, an insect juvenile hormone mimic formulated as Sumilarv® 0.5G, a 0.5% pyriproxyfen granule, (ii) expanded polystyrene beads (EPB), (iii) local soap or (iv) no treatment as controls. Flies were collected using exit traps placed over the drop holes, weekly for five weeks. In a separate study, we tested whether latrines also function as efficient flytraps using the faecal odours as attractants. We constructed six pit latrines each with a built-in flytrap and tested their catching efficiency compared to six fish-baited box traps positioned 10 m from the latrine. Focus group discussions conducted afterwards assessed the acceptability of the flytrap latrines. Results Numbers of emerging C. putoria were reduced by 96.0% (95% CIs: 94.5–97.2%) 4–5 weeks after treatment with pyriproxyfen; by 64.2% (95% CIs: 51.8–73.5%) after treatment with local soap; by 41.3% (95% CIs = 24.0–54.7%) after treatment with EPB 3–5 weeks after treatment. Flytraps placed on latrines collected C. putoria and were deemed acceptable to local communities. Conclusions Sumilarv 0.5G shows promise as a chemical control agent, whilst odour-baited latrine traps may prove a useful method of non-chemical fly control. Both methods warrant further development to reduce fly production from pit latrines. A combination of interventions may prove effective for the control of latrine flies and the diseases they transmit. PMID:23198767

  2. 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.

  3. LiPISC: A Lightweight and Flexible Method for Privacy-Aware Intersection Set Computation.

    PubMed

    Ren, Wei; Huang, Shiyong; Ren, Yi; Choo, Kim-Kwang Raymond

    2016-01-01

    Privacy-aware intersection set computation (PISC) can be modeled as secure multi-party computation. The basic idea is to compute the intersection of input sets without leaking privacy. Furthermore, PISC should be sufficiently flexible to recommend approximate intersection items. In this paper, we reveal two previously unpublished attacks against PISC, which can be used to reveal and link one input set to another input set, resulting in privacy leakage. We coin these as Set Linkage Attack and Set Reveal Attack. We then present a lightweight and flexible PISC scheme (LiPISC) and prove its security (including against Set Linkage Attack and Set Reveal Attack). PMID:27326763

  4. LiPISC: A Lightweight and Flexible Method for Privacy-Aware Intersection Set Computation

    PubMed Central

    Huang, Shiyong; Ren, Yi; Choo, Kim-Kwang Raymond

    2016-01-01

    Privacy-aware intersection set computation (PISC) can be modeled as secure multi-party computation. The basic idea is to compute the intersection of input sets without leaking privacy. Furthermore, PISC should be sufficiently flexible to recommend approximate intersection items. In this paper, we reveal two previously unpublished attacks against PISC, which can be used to reveal and link one input set to another input set, resulting in privacy leakage. We coin these as Set Linkage Attack and Set Reveal Attack. We then present a lightweight and flexible PISC scheme (LiPISC) and prove its security (including against Set Linkage Attack and Set Reveal Attack). PMID:27326763

  5. A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana)

    PubMed Central

    Stansfield, Fiona J.

    2015-01-01

    The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These ‘Age Reference Lines’ were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70–75 years. Methods to aid in molar identification and the sexing of found jaws were also identified. PMID:25970428

  6. A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana).

    PubMed

    Stansfield, Fiona J

    2015-01-01

    The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These 'Age Reference Lines' were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70-75 years. Methods to aid in molar identification and the sexing of found jaws were also identified.

  7. A Novel Objective Method of Estimating the Age of Mandibles from African Elephants (Loxodonta africana Africana).

    PubMed

    Stansfield, Fiona J

    2015-01-01

    The importance of assigning an accurate estimate of age and sex to elephant carcasses found in the wild has increased in recent years with the escalation in levels of poaching throughout Africa. Irregularities identified in current ageing techniques prompted the development of a new method to describe molar progression throughout life. Elephant mandibles (n = 323) were studied and a point near the distal dental alveolus was identified as being most useful in ranking each jaw according to molar progression. These 'Age Reference Lines' were then associated with an age scale based on previous studies and Zimbabwean mandibles of known age. The new ranking produced a single age scale that proved useful for both male and female mandibles up to the maximum lifespan age of 70-75 years. Methods to aid in molar identification and the sexing of found jaws were also identified. PMID:25970428

  8. Set-up and methods for SiPM Photo-Detection Efficiency measurements

    NASA Astrophysics Data System (ADS)

    Zappalà, G.; Acerbi, F.; Ferri, A.; Gola, A.; Paternoster, G.; Zorzi, N.; Piemonte, C.

    2016-08-01

    In this work, a compact set-up and three different methods to measure the Photo-Detection Efficiency (PDE) of Silicon Photomultipliers (SiPMs) and Single-Photon Avalanche Diodes (SPADs) are presented. The methods, based on either continuous or pulsed light illumination, are discussed in detail and compared in terms of measurement precision and time. For the SiPM, these methods have the feature of minimizing the effect of both the primary and correlated noise on the PDE estimation. The PDE of SiPMs (produced at FBK, Trento, Italy) was measured in a range from UV to NIR, obtaining similar results with all the methods. Furthermore, the advantages of measuring, when possible, the PDE of SPADs (of the same technology and with the same layout of a single SiPM cell) instead of larger devices are also discussed and a direct comparison between measurement results is shown. Using a SPAD, it is possible to reduce the measurement complexity and uncertainty since the correlated noise sources are reduced with respect to the SiPM case.

  9. A New Ghost Cell/Level Set Method for Moving Boundary Problems: Application to Tumor Growth

    PubMed Central

    Macklin, Paul

    2011-01-01

    In this paper, we present a ghost cell/level set method for the evolution of interfaces whose normal velocity depend upon the solutions of linear and nonlinear quasi-steady reaction-diffusion equations with curvature-dependent boundary conditions. Our technique includes a ghost cell method that accurately discretizes normal derivative jump boundary conditions without smearing jumps in the tangential derivative; a new iterative method for solving linear and nonlinear quasi-steady reaction-diffusion equations; an adaptive discretization to compute the curvature and normal vectors; and a new discrete approximation to the Heaviside function. We present numerical examples that demonstrate better than 1.5-order convergence for problems where traditional ghost cell methods either fail to converge or attain at best sub-linear accuracy. We apply our techniques to a model of tumor growth in complex, heterogeneous tissues that consists of a nonlinear nutrient equation and a pressure equation with geometry-dependent jump boundary conditions. We simulate the growth of glioblastoma (an aggressive brain tumor) into a large, 1 cm square of brain tissue that includes heterogeneous nutrient delivery and varied biomechanical characteristics (white matter, gray matter, cerebrospinal fluid, and bone), and we observe growth morphologies that are highly dependent upon the variations of the tissue characteristics—an effect observed in real tumor growth. PMID:21331304

  10. Fast Electron Correlation Methods for Molecular Clusters without Basis Set Superposition Errors

    SciTech Connect

    Kamiya, Muneaki; Hirata, So; Valiev, Marat

    2008-02-19

    Two critical extensions to our fast, accurate, and easy-to-implement binary or ternary interaction method for weakly-interacting molecular clusters [Hirata et al. Mol. Phys. 103, 2255 (2005)] have been proposed, implemented, and applied to water hexamers, hydrogen fluoride chains and rings, and neutral and zwitterionic glycine–water clusters with an excellent result for an initial performance assessment. Our original method included up to two- or three-body Coulomb, exchange, and correlation energies exactly and higher-order Coulomb energies in the dipole–dipole approximation. In this work, the dipole moments are replaced by atom-centered point charges determined so that they reproduce the electrostatic potentials of the cluster subunits as closely as possible and also self-consistently with one another in the cluster environment. They have been shown to lead to dramatic improvement in the description of short-range electrostatic potentials not only of large, charge-separated subunits like zwitterionic glycine but also of small subunits. Furthermore, basis set superposition errors (BSSE) known to plague direct evaluation of weak interactions have been eliminated by com-bining the Valiron–Mayer function counterpoise (VMFC) correction with our binary or ternary interaction method in an economical fashion (quadratic scaling n2 with respect to the number of subunits n when n is small and linear scaling when n is large). A new variant of VMFC has also been proposed in which three-body and all higher-order Coulomb effects on BSSE are estimated approximately. The BSSE-corrected ternary interaction method with atom-centered point charges reproduces the VMFC-corrected results of conventional electron correlation calculations within 0.1 kcal/mol. The proposed method is significantly more accurate and also efficient than conventional correlation methods uncorrected of BSSE.

  11. Speech-language assessment in a linguistically diverse setting: preliminary exploration of the possible impact of informal 'solutions' within the South African context.

    PubMed

    Barratt, Joanne; Khoza-Shangase, Katijah; Msimang, Kwandinjabulo

    2012-12-01

    Speech-language therapists (SLTs) working in the context of cultural and linguistic diversity face considerable challenges in providing equitable services to all clients. This is complicated by the fact that the majority ofSLTs in South Africa are English or Afrikaans speakers, while the majority of the population have a home language other than English/Afrikaans. Consequently, SLTs are often forced to call on untrained personnel to act as interpreters or translators, and to utilise informally translated materials in the assessment and management of clients with communication impairments. However, variations in translation have the potential to considerably alter intervention plans. This study explored whether the linguistic complexity conveyed in translation of the Western Aphasia Battery (WAB) test changed when translated from English to isiZulu by five different first-language IsiZulu speakers. A qualitative comparative research design was adopted and results were analysed using comparative data analysis. Results revealed notable differences in the translations, with most differences relating to vocabulary and semantics. This finding holds clinical implications for the use of informal translators as well as for the utilisation of translated material in the provision of speech-language therapy services in multilingual contexts. This study highlights the need for cautious use of translators and/or translated materials that are not appropriately and systematically adapted for local usage. Further recommendations include a call for intensified efforts in the transformation of the profession within the country, specifically by attracting greater numbers of students who are fluent in African languages.

  12. Large-Eddy Simulation of Premixed and Partially Premixed Turbulent Combustion Using a Level Set Method

    NASA Astrophysics Data System (ADS)

    Duchamp de Lageneste, Laurent; Pitsch, Heinz

    2001-11-01

    Level-set methods (G-equation) have been recently used in the context of RANS to model turbulent premixed (Hermann 2000) or partially premixed (Chen 1999) combustion. By directly taking into account unsteady effects, LES can be expected to improve predictions over RANS. Since the reaction zone thickness of premixed flames in technical devices is usually much smaller than the LES grid spacing, chemical reactions completely occur on the sub-grid scales and hence have to be modeled entirely. In the level-set methodology, the flame front is represented by an arbitrary iso-surface G0 of a scalar field G whose evolution is described by the so-called G-equation. This equation is only valid at G=G_0, and hence decoupled from other G levels. Heat release is then modeled using a flamelet approach in which temperature is determined as a function of G and the mixture-fraction Z. In the present study, the proposed approach has been formulated for LES and validated using data from a turbulent Bunsen burner experiment (Chen, Peters 1996). Simulation of an experimental Lean Premixed Prevapourised (LPP) dump combustor (Besson, Bruel 1999, 2000) under different premixed or partially premixed conditions will also be presented.

  13. Semi-Automated Detection of Surface Degradation on Bridges Based on a Level Set Method

    NASA Astrophysics Data System (ADS)

    Masiero, A.; Guarnieri, A.; Pirotti, F.; Vettore, A.

    2015-08-01

    Due to the effect of climate factors, natural phenomena and human usage, buildings and infrastructures are subject of progressive degradation. The deterioration of these structures has to be monitored in order to avoid hazards for human beings and for the natural environment in their neighborhood. Hence, on the one hand, monitoring such infrastructures is of primarily importance. On the other hand, unfortunately, nowadays this monitoring effort is mostly done by expert and skilled personnel, which follow the overall data acquisition, analysis and result reporting process, making the whole monitoring procedure quite expensive for the public (and private, as well) agencies. This paper proposes the use of a partially user-assisted procedure in order to reduce the monitoring cost and to make the obtained result less subjective as well. The developed method relies on the use of images acquired with standard cameras by even inexperienced personnel. The deterioration on the infrastructure surface is detected by image segmentation based on a level sets method. The results of the semi-automated analysis procedure are remapped on a 3D model of the infrastructure obtained by means of a terrestrial laser scanning acquisition. The proposed method has been successfully tested on a portion of a road bridge in Perarolo di Cadore (BL), Italy.

  14. Methods for intraoperative, sterile pose-setting of patient-specific microstereotactic frames

    NASA Astrophysics Data System (ADS)

    Vollmann, Benjamin; Müller, Samuel; Kundrat, Dennis; Ortmaier, Tobias; Kahrs, Lüder A.

    2015-03-01

    This work proposes new methods for a microstereotactic frame based on bone cement fixation. Microstereotactic frames are under investigation for minimal invasive temporal bone surgery, e.g. cochlear implantation, or for deep brain stimulation, where products are already on the market. The correct pose of the microstereotactic frame is either adjusted outside or inside the operating room and the frame is used for e.g. drill or electrode guidance. We present a patientspecific, disposable frame that allows intraoperative, sterile pose-setting. Key idea of our approach is bone cement between two plates that cures while the plates are positioned with a mechatronics system in the desired pose. This paper includes new designs of microstereotactic frames, a system for alignment and first measurements to analyze accuracy and applicable load.

  15. Treatability and characterization of Natural Organic Matter (NOM) in South African waters using newly developed methods

    NASA Astrophysics Data System (ADS)

    Nkambule, T. I.; Krause, R. W. M.; Haarhoff, J.; Mamba, B. B.

    Managing the removal of Natural Organic Matter (NOM) or problematic components from water has become increasingly important. NOM is a heterogeneous mixture of organic compounds of human origin and derived from plant and microbial residues. The inadequate removal of NOM has a bearing on the capacity of the other treatment processes to remove organic micro-pollutants or inorganic species that may be present in the water. In addition the action of certain disinfection processes has been shown to lead to the formation of harmful disinfection by-products (DBPs). Owing to the complexity, in composition and structure, of NOM, the techniques currently employed for its characterization have a number of limitations, both in terms of quantification and removal of the NOM within short periods of time. The dissolved organic carbon (DOC), biodegradable dissolved organic carbon (BDOC) and Fluorescence Emission Excitation Matrices (FEEM) were used to characterize NOM from various water samples collected around South Africa. Characterization results gave an indication of the character of NOM present in all the water samples. FEEM and UV-Vis results indicated that most of the water samples were aromatic in nature, since they had high hydrophobic and humic acid-like materials content. Generally, the characterization data indicated a varying composition of NOM amongst the various sampling points. The polarity rapid assessment method (PRAM) was then employed as a rapid NOM characterization tool. The characterization under PRAM is based on preferential adsorption of dissolved organic matter (DOM) fractions onto solid phase extraction (SPE) sorbents. The PRAM also allows the separation of DOM into fractions by polarity, hence reducing the molecular heterogeneity of NOM and thus aiding the removal of specific NOM fractions from water. The PRAM provided a quick characterization of the NOM character. However, DOC quantification by the PRAM analysis was hindered by excessive carbon leaching

  16. A method for testing railway wheel sets on a full-scale roller rig

    NASA Astrophysics Data System (ADS)

    Liu, Binbin; Bruni, Stefano

    2015-09-01

    Full-scale roller rigs for tests on a single axle enable the investigation of several dynamics and durability problems related with the design and operation of the railway rolling stock. In order to exploit the best potential of this test equipment, appropriate test procedures need to be defined, particularly in terms of actuators' references, to make sure that meaningful wheel -rail contact conditions can be reproduced. The aim of this paper is to propose a new methodology to define the forces to be generated by the actuators in the rig in order to best reproduce the behaviour of a wheel set and especially the wheel -rail contact forces in a running condition of interest as obtained either from multi-body system (MBS) simulation or from on-track measurements. The method is supported by the use of a mathematical model of the roller rig and uses an iterative correction scheme, comparing the time histories of the contact force components from the roller rig test as predicted by the mathematical model to a set of target contact force time histories. Two methods are introduced, the first one considering a standard arrangement of the roller rig, the second one assuming that a differential gear is introduced in the rig, allowing different rolling speeds of the two rollers. Results are presented showing that the deviation of the roller rig test results from the considered targets can be kept within low tolerances (1% approximately) as far as the vertical and lateral contact forces on both wheels are concerned. For the longitudinal forces, larger deviations are obtained except in the case where a differential gear is introduced.

  17. Analysis of bacterial communities of traditional fermented West African cereal foods using culture independent methods.

    PubMed

    Oguntoyinbo, Folarin A; Tourlomousis, Panagiotis; Gasson, Michael J; Narbad, Arjan

    2011-01-31

    In this study, the microbial composition of kunu-zaki and ogi, two popular foods in Nigeria produced after natural, uncontrolled fermentation of cereals, was assessed by culture-independent molecular profiling methods. In particular, PCR-denaturing gradient gel electrophoresis and construction of 16S rRNA gene clone libraries revealed the presence of diverse bacterial communities. DNA sequencing of the highly variable V3 region of the 16S rRNA genes obtained from PCR-DGGE fingerprints identified species related to Weissella confusa, Lactobacillus fermentum, Lactobacillus amylolyticus, Lactobacillus delbrueckii subsp. bulgaricus, Bacillus spp. and Lactococcus lactis spp lactis from food samples obtained from northern and southern geographical locations. A more comprehensive analysis of 272 full-length 16S rRNA gene inserts revealed that 70% of them were assigned to the Lactobacillaceae family and 19% to the Streptococcaceae family. Interestingly, sequences associated with a particular food type were also identified. For example, L. plantarum, L. pantheris and L. vaccinostercus were found in ogi but not in kunu-zaki while W. confusa, Streptococcus lutetiensis and Streptococcus gallolyticus subsp. macedonicus were found in kunu-zaki but not in ogi. Phylotypes corresponding to potentially pathogenic bacteria, such as Clostridium perfringens and Bacillus cereus were also detected highlighting the need for controlled fermentation processes.

  18. Design and methods for evaluating an early childhood obesity prevention program in the childcare center setting

    PubMed Central

    2013-01-01

    Background Many unhealthy dietary and physical activity habits that foster the development of obesity are established by the age of five. Presently, approximately 70 percent of children in the United States are currently enrolled in early childcare facilities, making this an ideal setting to implement and evaluate childhood obesity prevention efforts. We describe here the methods for conducting an obesity prevention randomized trial in the child care setting. Methods/design A randomized, controlled obesity prevention trial is currently being conducted over a three year period (2010-present). The sample consists of 28 low-income, ethnically diverse child care centers with 1105 children (sample is 60% Hispanic, 15% Haitian, 12% Black, 2% non-Hispanic White and 71% of caregivers were born outside of the US). The purpose is to test the efficacy of a parent and teacher role-modeling intervention on children’s nutrition and physical activity behaviors. . The Healthy Caregivers-Healthy Children (HC2) intervention arm schools received a combination of (1) implementing a daily curricula for teachers/parents (the nutritional gatekeepers); (2) implementing a daily curricula for children; (3) technical assistance with meal and snack menu modifications such as including more fresh and less canned produce; and (4) creation of a center policy for dietary requirements for meals and snacks, physical activity and screen time. Control arm schools received an attention control safety curriculum. Major outcome measures include pre-post changes in child body mass index percentile and z score, fruit and vegetable and other nutritious food intake, amount of physical activity, and parental nutrition and physical activity knowledge, attitudes, and beliefs, defined by intentions and behaviors. All measures were administered at the beginning and end of the school year for year one and year two of the study for a total of 4 longitudinal time points for assessment. Discussion Although few

  19. Speech-language assessment in a linguistically diverse setting: preliminary exploration of the possible impact of informal 'solutions' within the South African context.

    PubMed

    Barratt, Joanne; Khoza-Shangase, Katijah; Msimang, Kwandinjabulo

    2012-12-01

    Speech-language therapists (SLTs) working in the context of cultural and linguistic diversity face considerable challenges in providing equitable services to all clients. This is complicated by the fact that the majority ofSLTs in South Africa are English or Afrikaans speakers, while the majority of the population have a home language other than English/Afrikaans. Consequently, SLTs are often forced to call on untrained personnel to act as interpreters or translators, and to utilise informally translated materials in the assessment and management of clients with communication impairments. However, variations in translation have the potential to considerably alter intervention plans. This study explored whether the linguistic complexity conveyed in translation of the Western Aphasia Battery (WAB) test changed when translated from English to isiZulu by five different first-language IsiZulu speakers. A qualitative comparative research design was adopted and results were analysed using comparative data analysis. Results revealed notable differences in the translations, with most differences relating to vocabulary and semantics. This finding holds clinical implications for the use of informal translators as well as for the utilisation of translated material in the provision of speech-language therapy services in multilingual contexts. This study highlights the need for cautious use of translators and/or translated materials that are not appropriately and systematically adapted for local usage. Further recommendations include a call for intensified efforts in the transformation of the profession within the country, specifically by attracting greater numbers of students who are fluent in African languages. PMID:23409617

  20. Emergency obstetrical complications in a rural African setting (Kayes, Mali): the link between travel time and in-hospital maternal mortality.

    PubMed

    Pirkle, Catherine McLean; Fournier, Pierre; Tourigny, Caroline; Sangaré, Karim; Haddad, Slim

    2011-10-01

    The West African country of Mali implemented referral systems to increase spatial access to emergency obstetrical care and lower maternal mortality. We test the hypothesis that spatial access- proxied by travel time during the rainy and dry seasons- is associated with in-hospital maternal mortality. Effect modification by caesarean section is explored. All women treated for emergency obstetrical complications at the referral hospital in Kayes, Mali were considered eligible for study. First, we conducted descriptive analyses of all emergency obstetrical complications treated at the referral hospital between 2005 and 2007. We calculated case fatality rates by obstetric diagnosis and travel time. Key informant interviews provided travel times. Medical registers provided clinical and demographic data. Second, a matched case-control study assessed the independent effect of travel time on maternal mortality. Stratification was used to explore effect modification by caesarean section. Case fatality rates increased with increasing travel time to the hospital. After controlling for age, diagnosis, and date of arrival, a travel time of four or more hours was significantly associated with in-hospital maternal mortality (OR: 3.83; CI: 1.31-11.27). Travel times between 2 and 4 h were associated with increased odds of maternal mortality (OR 1.88), but the relationship was not significant. The effect of travel time on maternal mortality appears to be modified by caesarean section. Poor spatial access contributes to maternal mortality even in women who reach a health facility. Improving spatial access will help women arrive at the hospital in time to be treated effectively.

  1. Comparison of several BHT correction methods: a case study on an Australian data set

    NASA Astrophysics Data System (ADS)

    Goutorbe, Bruno; Lucazeau, Francis; Bonneville, Alain

    2007-08-01

    Bottom-hole temperatures (BHT) from oil exploration provide useful constraints on the subsurface thermal regime, but they need to be corrected to obtain the equilibrium temperature. In this work, we introduce several BHT correction methods and compare them using a large Australian data set of more than 650 groups of multiple BHT measurements in about 300 oil exploration boreholes. Existing and suggested corrections are classified within a coherent framework, in which methods are divided into: line/cylinder source; instantaneous/continuous heat extraction; one/two component(s). Comparisons with reservoir test temperatures show that most of the corrections lead to reliable estimates of the formation equilibrium temperature within +/-10°C, but too few data exist to perform an intercomparison of the models based on this criterion. As expected, the Horner method diverges from its parent models for small elapsed times (or equivalently large radii). The mathematical expression of line source models suffers from an unphysical delay time that also restrains their domain of applicability. The model that takes into account the difference of thermal properties between circulating mud and surrounding rocks-that is the two-component model-is delicate to use because of its high complexity. For these reasons, our preferred correction methods are the cylindrical source models. We show that mud circulation time below 10 hr has a negligible effect. The cylindrical source models rely on one parameter depending on the thermal diffusivity and the borehole radius, which are poorly constrained, but the induced uncertainty on the extrapolations remains reasonably low.

  2. Balancing acts: A mixed methods study of the figured world of African American 7th graders in urban science classrooms

    NASA Astrophysics Data System (ADS)

    Cleveland-Solomon, Tanya E.

    What beliefs and cultural models do youth who are underrepresented in science have about the domain of science and about themselves as science learners? What do they imagine is possible for them in relation to science both now and in the future? In other words, what constitutes their figured world of science? This dissertation study, using a mixed methods design, offers new perspectives on the ways that underrepresented youth's unexamined assumptions or cultural models and resources may shape their identities and motivation to learn science. Through analyses of survey and interview data, I found that urban African American youths' social context, gender, racial identity, and perceptions of the science they had in school influenced their motivation to learn science. Analyses of short-term classroom observations and interviews suggested that students had competing cultural models that they used in their constructions of identities as science learners, which they espoused and adopted in relation to how well they leveraged the science-related cultural resources available to them. Results from this study suggested that these 7th graders would benefit from access to more expansive cultural models through access to individuals with scientific capital as a way to allow them to create fruitful identities as science learners. If we want to ensure that students from groups that are underrepresented in science not only have better outcomes, but aspire to and enter the science career pipeline, we must also begin to support them in their negotiations of competing cultural models that limit their ability to adopt science-learner identities in their classrooms. This study endeavored to understand the particular cultural models and motivational beliefs that drive students to act, and what types of individuals they imagine scientists and science workers to be. This study also examined how cultural models and resources influence identity negotiation, specifically the roles youths

  3. Redefining racial residential segregation and its association with physical activity among African Americans 50 years and older: a mixed methods approach.

    PubMed

    Armstrong-Brown, Janell; Eng, Eugenia; Hammond, Wizdom Powell; Zimmer, Catherine; Bowling, J Michael

    2015-04-01

    Physical inactivity is one of the factors contributing to disproportionate disease rates among older African Americans. Previous literature indicates that older African Americans are more likely to live in racially segregated neighborhoods and that racial residential segregation is associated with limited opportunities for physical activity. A cross-sectional mixed methods study was conducted guided by the concept of therapeutic landscapes. Multilevel regression analyses demonstrated that racial residential segregation was associated with more minutes of physical activity and greater odds of meeting physical activity recommendations. Qualitative interviews revealed the following physical activity related themes: aging of the neighborhood, knowing your neighbors, feeling of safety, and neighborhood racial identity. Perceptions of social cohesion enhanced participants' physical activity, offering a plausible explanation to the higher rates of physical activity found in this population. Understanding how social cohesion operates within racially segregated neighborhoods can help to inform the design of effective interventions for this population.

  4. Determination of dimensional flow fields in hydrogeological settings via the MRT lattice-Boltzmann method

    NASA Astrophysics Data System (ADS)

    Hilpert, Markus

    2011-09-01

    In this paper we demonstrate how the single and multiple-relaxation-time (MRT) lattice-Boltzmann (LB) method can be used to simulate hydrogeological flows under standard conditions. We explain in detail how real-world hydrogeological flow problems, which are formulated in terms of dimensional boundary and initial conditions, can be related to the nondimensional LB world, in which both the lattice spacing and the time step are nondimensional and typically set to unity. We first demonstrate the method in two examples where analytical solutions are known: steady state and transient flow of water in a square duct where fluid inertia is either negligible or not, respectively. Finally we simulate the flow of water in a sand where inertial forces are not negligible. For steady state flow we also present equations for calculating the permeability. Moreover, we demonstrate and advocate the usage of Richardson's extrapolation, which allows one to estimate LB modeling results for an infinite numerical resolution that include uncertainty intervals. For pressure-driven simulations of steady state creeping flow, we show how one can improve the numerical convergence behavior by performing "light-water" simulations at a lower Reynolds number while still predicting the correct velocity field.

  5. DSA Image Blood Vessel Skeleton Extraction Based on Anti-concentration Diffusion and Level Set Method

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Wu, Jian; Feng, Daming; Cui, Zhiming

    Serious types of vascular diseases such as carotid stenosis, aneurysm and vascular malformation may lead to brain stroke, which are the third leading cause of death and the number one cause of disability. In the clinical practice of diagnosis and treatment of cerebral vascular diseases, how to do effective detection and description of the vascular structure of two-dimensional angiography sequence image that is blood vessel skeleton extraction has been a difficult study for a long time. This paper mainly discussed two-dimensional image of blood vessel skeleton extraction based on the level set method, first do the preprocessing to the DSA image, namely uses anti-concentration diffusion model for the effective enhancement and uses improved Otsu local threshold segmentation technology based on regional division for the image binarization, then vascular skeleton extraction based on GMM (Group marching method) with fast sweeping theory was actualized. Experiments show that our approach not only improved the time complexity, but also make a good extraction results.

  6. Research on the feature set construction method for spherical stereo vision

    NASA Astrophysics Data System (ADS)

    Zhu, Junchao; Wan, Li; Röning, Juha; Feng, Weijia

    2015-01-01

    Spherical stereo vision is a kind of stereo vision system built by fish-eye lenses, which discussing the stereo algorithms conform to the spherical model. Epipolar geometry is the theory which describes the relationship of the two imaging plane in cameras for the stereo vision system based on perspective projection model. However, the epipolar in uncorrected fish-eye image will not be a line but an arc which intersects at the poles. It is polar curve. In this paper, the theory of nonlinear epipolar geometry will be explored and the method of nonlinear epipolar rectification will be proposed to eliminate the vertical parallax between two fish-eye images. Maximally Stable Extremal Region (MSER) utilizes grayscale as independent variables, and uses the local extremum of the area variation as the testing results. It is demonstrated in literatures that MSER is only depending on the gray variations of images, and not relating with local structural characteristics and resolution of image. Here, MSER will be combined with the nonlinear epipolar rectification method proposed in this paper. The intersection of the rectified epipolar and the corresponding MSER region is determined as the feature set of spherical stereo vision. Experiments show that this study achieved the expected results.

  7. Governance of professional nursing practice in a hospital setting: a mixed methods study1

    PubMed Central

    dos Santos, José Luís Guedes; Erdmann, Alacoque Lorenzini

    2015-01-01

    Objective: to elaborate an interpretative model for the governance of professional nursing practice in a hospital setting. Method: a mixed methods study with concurrent triangulation strategy, using data from a cross-sectional study with 106 nurses and a Grounded Theory study with 63 participants. The quantitative data were collected through the Brazilian Nursing Work Index - Revised and underwent descriptive statistical analysis. Qualitative data were obtained from interviews and analyzed through initial, selective and focused coding. Results: based on the results obtained with the Brazilian Nursing Work Index - Revised, it is possible to state that nurses perceived that they had autonomy, control over the environment, good relationships with physicians and organizational support for nursing governance. The governance of the professional nursing practice is based on the management of nursing care and services carried out by the nurses. To perform these tasks, nurses aim to get around the constraints of the organizational support and develop management knowledge and skills. Conclusion: it is important to reorganize the structures and processes of nursing governance, especially the support provided by the organization for the management practices of nurses. PMID:26625992

  8. Set of new draft methods for the analysis of organic disinfection by-products, including 551 and 552. Draft report

    SciTech Connect

    Not Available

    1993-01-01

    The set of documents discusses the new draft methods (EPA method 551, EPA method 552) for the analysis of disinfection byproducts contained in drinking water. The methods use the techniques of liquid/liquid extraction and gas chromatography with electron capture detection.

  9. High-Order Discontinuous Galerkin Level Set Method for Interface Tracking and Re-Distancing on Unstructured Meshes

    NASA Astrophysics Data System (ADS)

    Greene, Patrick; Nourgaliev, Robert; Schofield, Sam

    2015-11-01

    A new sharp high-order interface tracking method for multi-material flow problems on unstructured meshes is presented. The method combines the marker-tracking algorithm with a discontinuous Galerkin (DG) level set method to implicitly track interfaces. DG projection is used to provide a mapping from the Lagrangian marker field to the Eulerian level set field. For the level set re-distancing, we developed a novel marching method that takes advantage of the unique features of the DG representation of the level set. The method efficiently marches outward from the zero level set with values in the new cells being computed solely from cell neighbors. Results are presented for a number of different interface geometries including ones with sharp corners and multiple hierarchical level sets. The method can robustly handle the level set discontinuities without explicit utilization of solution limiters. Results show that the expected high order (3rd and higher) of convergence for the DG representation of the level set is obtained for smooth solutions on unstructured meshes. High-order re-distancing on irregular meshes is a must for applications were the interfacial curvature is important for underlying physics, such as surface tension, wetting and detonation shock dynamics. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Information management release number LLNL-ABS-675636.

  10. Comparison of Web-Based and Face-to-Face Standard Setting Using the Angoff Method

    ERIC Educational Resources Information Center

    Katz, Irvin R.; Tannenbaum, Richard J.

    2014-01-01

    Web-based standard setting holds promise for reducing the travel and logistical inconveniences of traditional, face-to-face standard setting meetings. However, because there are few published reports of setting standards via remote meeting technology, little is known about the practical potential of the approach, including technical feasibility of…

  11. An abdominal aortic aneurysm segmentation method: Level set with region and statistical information

    SciTech Connect

    Zhuge Feng; Rubin, Geoffrey D.; Sun Shaohua; Napel, Sandy

    2006-05-15

    We present a system for segmenting the human aortic aneurysm in CT angiograms (CTA), which, in turn, allows measurements of volume and morphological aspects useful for treatment planning. The system estimates a rough 'initial surface', and then refines it using a level set segmentation scheme augmented with two external analyzers: The global region analyzer, which incorporates a priori knowledge of the intensity, volume, and shape of the aorta and other structures, and the local feature analyzer, which uses voxel location, intensity, and texture features to train and drive a support vector machine classifier. Each analyzer outputs a value that corresponds to the likelihood that a given voxel is part of the aneurysm, which is used during level set iteration to control the evolution of the surface. We tested our system using a database of 20 CTA scans of patients with aortic aneurysms. The mean and worst case values of volume overlap, volume error, mean distance error, and maximum distance error relative to human tracing were 95.3%{+-}1.4% (s.d.); worst case=92.9%, 3.5%{+-}2.5% (s.d.); worst case=7.0%, 0.6{+-}0.2 mm (s.d.); worst case=1.0 mm, and 5.2{+-}2.3mm (s.d.); worstcase=9.6 mm, respectively. When implemented on a 2.8 GHz Pentium IV personal computer, the mean time required for segmentation was 7.4{+-}3.6min (s.d.). We also performed experiments that suggest that our method is insensitive to parameter changes within 10% of their experimentally determined values. This preliminary study proves feasibility for an accurate, precise, and robust system for segmentation of the abdominal aneurysm from CTA data, and may be of benefit to patients with aortic aneurysms.

  12. A-type magmatism in a syn-collisional setting: The case of the Pan-African Hook Batholith in Central Zambia

    NASA Astrophysics Data System (ADS)

    Milani, Lorenzo; Lehmann, Jérémie; Naydenov, Kalin V.; Saalmann, Kerstin; Kinnaird, Judith A.; Daly, J. Stephen; Frei, Dirk; Lobo-Guerrero Sanz, Alberto

    2015-02-01

    The Pan-African Hook Batholith formed during the assembly of the Gondwana supercontinent as a result of syn-collisional stage interaction between the Congo and Kalahari Cratons. The bimodal magmatism (mafic to predominantly felsic) is characterized by both an alkali-calcic and an alkalic suite, with typical A-type, metaluminous, high Fe/Mg and K/Na geochemical signature. Occasionally, sodic granitoids have been documented. Compositions were driven to more differentiated products by fractional crystallization, while Sr-Nd isotopes exclude crustal assimilation during crystallization. Recent new U-Pb age data constrain most of the felsic magmatism between 550 and 540 Ma. Scattered outcrops of gabbroic rocks, both tholeiitic and alkaline, testify to periodic input of mantle material, and, in some cases, to interaction with metasomatizing fluids. Crystallization ages on mafic rocks span from 570 to 520 Ma, thus indicating that they were contemporaneous with the major granitic intrusion, which was the result of a number of successive felsic batches, eventually forming a coalescing batholith. Highly radiogenic Pb isotopic values attest to the radiogenic character of the rocks. Such an anomalous signature was acquired during, or soon after, magma emplacement, perhaps as result of metasomatizing fluids. Enrichment in Th-U of large portions of the crust along this part of the margin of the Congo Craton is suggested. Geochemical and isotopic evidence support the interaction between mantle components and portions of the deep crust at pressure of < 10 kbar, while decompression melting of rising asthenospheric mantle ponding at the base of the crust heated, and ultimately melted, crustal material. An additional and crucial contribution to the crustal melting was likely provided by internal radiogenic heat production of the thickened crust, and is in agreement with the high radioactivity of the pluton. A tectono-thermal model, implying crustal accretion accompanied by slab

  13. Gliding Box method applied to trace element distribution of a geochemical data set

    NASA Astrophysics Data System (ADS)

    Paz González, Antonio; Vidal Vázquez, Eva; Rosario García Moreno, M.; Paz Ferreiro, Jorge; Saa Requejo, Antonio; María Tarquis, Ana

    2010-05-01

    The application of fractal theory to process geochemical prospecting data can provide useful information for evaluating mineralization potential. A geochemical survey was carried out in the west area of Coruña province (NW Spain). Major elements and trace elements were determined by standard analytical techniques. It is well known that there are specific elements or arrays of elements, which are associated with specific types of mineralization. Arsenic has been used to evaluate the metallogenetic importance of the studied zone. Moreover, as can be considered as a pathfinder of Au, as these two elements are genetically associated. The main objective of this study was to use multifractal analysis to characterize the distribution of three trace elements, namely Au, As, and Sb. Concerning the local geology, the study area comprises predominantly acid rocks, mainly alkaline and calcalkaline granites, gneiss and migmatites. The most significant structural feature of this zone is the presence of a mylonitic band, with an approximate NE-SW orientation. The data set used in this study comprises 323 samples collected, with standard geochemical criteria, preferentially in the B horizon of the soil. Occasionally where this horizon was not present, samples were collected from the C horizon. Samples were taken in a rectilinear grid. The sampling lines were perpendicular to the NE-SW tectonic structures. Frequency distributions of the studied elements departed from normal. Coefficients of variation ranked as follows: Sb < As < Au. Significant correlation coefficients between Au, Sb, and As were found, even if these were low. The so-called ‘gliding box' algorithm (GB) proposed originally for lacunarity analysis has been extended to multifractal modelling and provides an alternative to the ‘box-counting' method for implementing multifractal analysis. The partitioning method applied in GB algorithm constructs samples by gliding a box of certain size (a) over the grid map in all

  14. The 'Fears' of Disclosing HIV Status to Sexual Partners: A Mixed Methods Study in a Counseling Setting in Ghana.

    PubMed

    Obiri-Yeboah, D; Amoako-Sakyi, D; Baidoo, I; Adu-Oppong, A; Rheinländer, T

    2016-01-01

    Encouraging disclosure within a trusting and supportive environment is imperative in dealing with HIV/AIDS related stigma. However, disclosure rates and the factors that influence it are vaguely understood in African societies. This study aimed at determining the disclosure rate and factors that influence disclosure in Cape Coast, Ghana. In-depth interviews of 15 peer educators and a survey of 510 PLHIV were used in a mixed methods study design. Majority of the study participants (78.6 %) had disclosed their HIV positive status to their sexual partners. Although peer educators in this study portrayed the overall outcome of disclosure to be negative, 84.0 % of disclosers were accepted by their partners without negative consequences after disclosure. This study suggests that the existing support services ill prepares newly diagnosed HIV positive clients and hampers disclosure initiatives. Providing comprehensive support services and re-training peer educators may be crucial in creating a safe disclosure environment in Ghana.

  15. Why did she put nail polish in my drink? Applying the Therapeutic Assessment model with an African American foster child in a community mental health setting.

    PubMed

    Guerrero, Brooke; Lipkind, Jessica; Rosenberg, Audrey

    2011-01-01

    Although the majority of research on Therapeutic Assessment (TA) discusses the application of TA in research or private practice settings, we found that the model could be applied in a community mental health setting. We argue that when implementing this model with racially diverse, low socioeconomic status children, it is essential to integrate issues of class, privilege, and race into the assessment process. A case is presented that illuminates the specific concerns and struggles of adapting this model to a community psychology population. This analysis includes the interface with systems, placement stability, and consideration of culturally responsible treatment. We also demonstrate how the support of a treatment team helps the individual clinician process and integrate the levels of trauma and pain with which these families present. PMID:21184324

  16. The structure and material composition of ossified aortic valves identified using a set of scientific methods

    NASA Astrophysics Data System (ADS)

    Zeman, Antonín; Šmíd, Michal; Havelcová, Martina; Coufalová, Lucie; Kučková, Štěpánka; Velčovská, Martina; Hynek, Radovan

    2013-11-01

    Degenerative aortic stenosis has become a common and dangerous disease in recent decades. This disease leads to the mineralization of aortic valves, their gradual thickening and loss of functionality. We studied the detailed assessment of the proportion and composition of inorganic and organic components in the ossified aortic valve, using a set of analytical methods applied in science: polarized light microscopy, scanning electron microscopy, X-ray fluorescence, X-ray diffraction, gas chromatography/mass spectrometry and liquid chromatography-tandem mass spectrometry. The sample valves showed the occurrence of phosphorus and calcium in the form of phosphate and calcium carbonate, hydroxyapatite, fluorapatite and hydroxy-fluorapatite, with varying content of inorganic components from 65 to 90 wt%, and with phased development of degenerative disability. The outer layers of the plaque contained an organic component with peptide bonds, fatty acids, proteins and cholesterol. The results show a correlation between the formation of fluorapatite in aortic valves and in other parts of the human bodies, associated with the formation of bones.

  17. Parameters influencing the location and characteristics of volcanic eruptions in a youthful extensional setting: Insights from the Virunga Volcanic Province, in the Western Branch of the East African Rift System

    NASA Astrophysics Data System (ADS)

    Smets, Benoît; d'Oreye, Nicolas; Kervyn, Matthieu; Kervyn, François

    2016-04-01

    The East African Rift System (EARS) is often mentioned as the modern archetype for rifting and continental break-up (Calais et al., 2006, GSL Special Publication 259), showing the complex interaction between rift faults, magmatism and pre-existing structures of the basement. Volcanism in the EARS is characterized by very active volcanoes, several of them being among the most active on Earth (Wright et al., 2015, GRL 42). Such intense volcanic activity provides useful information to study the relationship between rifting, magmatism and volcanism. This is the case of the Virunga Volcanic Province (VVP) located in the central part of the Western Branch of the EARS, which hosts two of the most active African volcanoes, namely Nyiragongo and Nyamulagira. Despite the intense eruptive activity in the VVP, the spatial distribution of volcanism and its relationship with the extensional setting remain little known. Here we present a study of the interaction between tectonics, magmatism and volcanism at the scale of the Kivu rift section, where the VVP is located, and at the scale of a volcano, by studying the dense historical eruptive activity of Nyamulagira. Both the complex Precambrian basement and magmatism appear to contribute to the development of the Kivu rift. The presence of transfer zones north and south of the Lake Kivu rift basin favoured the development of volcanic provinces at these locations. Rift faults, including reactivated Precambrian structures influenced the location of volcanism within the volcanic provinces and the rift basin. At a more local scale, the historical eruptive activity of Nyamulagira highlights that, once a composite volcano developed, the gravitational stress field induced by edifice loading becomes the main parameter that influence the location, duration and lava volume of eruptions.

  18. A Standard Setting Method Designed for Complex Performance Assessments with Multiple Performance Categories: Categorical Assignments of Student Work.

    ERIC Educational Resources Information Center

    Plake, Barbara S.; Hambleton, Ronald K.

    This paper reports on a standard-setting method designed for complex performance assessments with multiple performance categories. The method studied, the Analytical Judgment Method, involves panelists' making analytical classification decisions for each of the test's components individually. It also allows for discussion and reconsideration of…

  19. Straight ladder inclined angle in a field environment: the relationship among actual angle, method of set-up and knowledge

    PubMed Central

    Chang, Wen-Ruey; Huang, Yueng-Hsiang; Chang, Chien-Chi; Brunette, Christopher; Fallentin, Nils

    2016-01-01

    Abstract Ladder inclined angle is a critical factor that could lead to a slip at the base of portable straight ladders, a major cause of falls from heights. Despite several methods established to help workers achieve the recommended 75.5° angle for ladder set-up, it remains unclear if these methods are used in practice. This study explored ladder set-up behaviours in a field environment. Professional installers of a company in the cable and other pay TV industry were observed for ladder set-up at their worksites. The results showed that the actual angles of 265 ladder set-ups by 67 participants averaged 67.3° with a standard deviation of 3.22°. Although all the participants had training on recommended ladder set-up methods, only 3 out of 67 participants applied these methods in their daily work and even they failed to achieve the desired 75.5° angle. Therefore, ladder set-up remains problematic in real-world situations. Practitioner Summary: Professional installers of a cable company were observed for portable straight ladder set-up at their worksites. The ladder inclined angle averaged 67.3° with a standard deviation of 3.22°, while the recommended angle is 75.5°. Only a few participants used the methods that they learned during training in their daily work. PMID:26672809

  20. Straight ladder inclined angle in a field environment: the relationship among actual angle, method of set-up and knowledge.

    PubMed

    Chang, Wen-Ruey; Huang, Yueng-Hsiang; Chang, Chien-Chi; Brunette, Christopher; Fallentin, Nils

    2016-08-01

    Ladder inclined angle is a critical factor that could lead to a slip at the base of portable straight ladders, a major cause of falls from heights. Despite several methods established to help workers achieve the recommended 75.5° angle for ladder set-up, it remains unclear if these methods are used in practice. This study explored ladder set-up behaviours in a field environment. Professional installers of a company in the cable and other pay TV industry were observed for ladder set-up at their worksites. The results showed that the actual angles of 265 ladder set-ups by 67 participants averaged 67.3° with a standard deviation of 3.22°. Although all the participants had training on recommended ladder set-up methods, only 3 out of 67 participants applied these methods in their daily work and even they failed to achieve the desired 75.5° angle. Therefore, ladder set-up remains problematic in real-world situations. Practitioner Summary: Professional installers of a cable company were observed for portable straight ladder set-up at their worksites. The ladder inclined angle averaged 67.3° with a standard deviation of 3.22°, while the recommended angle is 75.5°. Only a few participants used the methods that they learned during training in their daily work.

  1. Modeling Primary Breakup: A Three-Dimensional Eulerian Level Set/Vortex Sheet Method for Two-Phase Interface Dynamics

    NASA Technical Reports Server (NTRS)

    Herrmann, M.

    2003-01-01

    This paper is divided into four parts. First, the level set/vortex sheet method for three-dimensional two-phase interface dynamics is presented. Second, the LSS model for the primary breakup of turbulent liquid jets and sheets is outlined and all terms requiring subgrid modeling are identified. Then, preliminary three-dimensional results of the level set/vortex sheet method are presented and discussed. Finally, conclusions are drawn and an outlook to future work is given.

  2. A Classification Method of Inquiry E-mails for Describing FAQ with Automatic Setting Mechanism of Judgment Thresholds

    NASA Astrophysics Data System (ADS)

    Tsuda, Yuki; Akiyoshi, Masanori; Samejima, Masaki; Oka, Hironori

    In this paper the authors propose a classification method of inquiry e-mails for describing FAQ (Frequently Asked Questions) and automatic setting mechanism of judgment thresholds. In this method, a dictionary used for classification of inquiries is generated and updated automatically by statistical information of characteristic words in clusters, and inquiries are classified correctly to each proper cluster by using the dictionary. Threshold values are automatically set by using statistical information.

  3. Inkwari: An Emerging High-Risk Place Potentiating HIV Spread Among Young Adults in a Hyper-Endemic South African Setting

    PubMed Central

    Closson, Elizabeth F.; Safren, Steven A.; Mabude, Zonke; Mosery, Nzwakie; Taylor, Scott W.; Perez-Brumer, Amaya; Matthews, Lynn T.; Psaros, Christina; Harrison, Abigail; Grelotti, David J.; Bangsberg, David R.; Smit, Jennifer A.

    2015-01-01

    Young adults in South Africa are at the epicenter of the HIV epidemic. The prevalence of HIV among young people in the province of KwaZulu-Natal (KZN) is particularly high. This study characterizes inkwari (Zulu word for raves or weekend-long parties) in eThekwini District, KZN and explored how these place-based dynamics shape the risk environment for the young adult attendees. In 2011, 13 qualitative interviews were conducted with men and women between 18 and 30 years-old who reported unprotected sex with at least one casual partner in the prior 3 months and attended an inkwari in the same time period. Interviews were analyzed using qualitative content analysis. Nine key informant interviews helped to triangulate these data. Five women and eight men were interviewed and the mean age was 25 years (SD 3.24). Ten reported meeting a sexual partner at an inkwari. Inkwari were characterized as sexualized settings with limited adult supervision. Participants attended inkwari to socialize with peers, use drugs and alcohol, and meet sexual partners. Sexual and physical violence also occurred at inkwari. Given the convergence of social, sexual, and substance- using networks at inkwari, further inquiry is needed to determine how this place may potentiate HIV transmission risk in an endemic setting. PMID:25091214

  4. A FORTRAN program for the statistical analysis of incomplete time series data sets by a method of partition.

    PubMed

    Patel, M K; Waterhouse, J P

    1993-03-01

    A program written in FORTRAN-77 which executes an analysis for periodicity of a time series data set is presented. Time series analysis now has applicability and use in a wide range of biomedical studies. The analytical method termed here a method of partition is derived from periodogram analysis, but uses the principle of analysis of variance (ANOVA). It is effective when used on incomplete data sets. An example in which a data set is made progressively more incomplete by the random removal of values demonstrates this, and a listing of the program and a sample output in both an abbreviated and a full version are given.

  5. Angoff Method of Setting Cut Scores for High-Stakes Testing: Foley Catheter Checkoff as an Exemplar.

    PubMed

    Kardong-Edgren, Suzan; Mulcock, Pamela M

    2016-01-01

    The Angoff method is a commonly used and legally defensible method for setting passing or cut scores for high-stakes examinations. It also can be used for setting passing scores on clinical skill checklists. Two variations of the Angoff method were compared with a traditional and arbitrary 75% passing score, using a Foley catheter insertion checklist as an exemplar. Both Angoff methods produced slightly lower scores than our traditional scoring; because of "must pass" steps on our checklist, 12 of 13 students still failed the evaluation. The project uncovered multiple variations of checklists within different courses and variations in teaching practices for this skill. PMID:26402909

  6. Angoff Method of Setting Cut Scores for High-Stakes Testing: Foley Catheter Checkoff as an Exemplar.

    PubMed

    Kardong-Edgren, Suzan; Mulcock, Pamela M

    2016-01-01

    The Angoff method is a commonly used and legally defensible method for setting passing or cut scores for high-stakes examinations. It also can be used for setting passing scores on clinical skill checklists. Two variations of the Angoff method were compared with a traditional and arbitrary 75% passing score, using a Foley catheter insertion checklist as an exemplar. Both Angoff methods produced slightly lower scores than our traditional scoring; because of "must pass" steps on our checklist, 12 of 13 students still failed the evaluation. The project uncovered multiple variations of checklists within different courses and variations in teaching practices for this skill.

  7. Setting health research priorities using the CHNRI method: VI. Quantitative properties of human collective opinion

    PubMed Central

    Yoshida, Sachiyo; Rudan, Igor; Cousens, Simon

    2016-01-01

    Introduction Crowdsourcing has become an increasingly important tool to address many problems – from government elections in democracies, stock market prices, to modern online tools such as TripAdvisor or Internet Movie Database (IMDB). The CHNRI method (the acronym for the Child Health and Nutrition Research Initiative) for setting health research priorities has crowdsourcing as the major component, which it uses to generate, assess and prioritize between many competing health research ideas. Methods We conducted a series of analyses using data from a group of 91 scorers to explore the quantitative properties of their collective opinion. We were interested in the stability of their collective opinion as the sample size increases from 15 to 90. From a pool of 91 scorers who took part in a previous CHNRI exercise, we used sampling with replacement to generate multiple random samples of different size. First, for each sample generated, we identified the top 20 ranked research ideas, among 205 that were proposed and scored, and calculated the concordance with the ranking generated by the 91 original scorers. Second, we used rank correlation coefficients to compare the ranks assigned to all 205 proposed research ideas when samples of different size are used. We also analysed the original pool of 91 scorers to to look for evidence of scoring variations based on scorers' characteristics. Results The sample sizes investigated ranged from 15 to 90. The concordance for the top 20 scored research ideas increased with sample sizes up to about 55 experts. At this point, the median level of concordance stabilized at 15/20 top ranked questions (75%), with the interquartile range also generally stable (14–16). There was little further increase in overlap when the sample size increased from 55 to 90. When analysing the ranking of all 205 ideas, the rank correlation coefficient increased as the sample size increased, with a median correlation of 0.95 reached at the sample size

  8. Expert Consensus on the Rehabilitation Framework Guiding a Model of Care for People Living With HIV in a South African Setting.

    PubMed

    Chetty, Verusia; Hanass-Hancock, Jill; Myezwa, Hellen

    2016-01-01

    Disabilities and treatments related to HIV are a focus for rehabilitation professionals in HIV-endemic countries, yet these countries lack guidance to integrate rehabilitation into a model of care for people living with HIV. We asked HIV and rehabilitation experts in South Africa to engage in a modified Delphi survey based on findings from (a) an enquiry into stakeholder perspectives of a context-specific rehabilitation framework at a semi-rural setting and (b) an analysis of international models of care-guiding rehabilitation. Consensus was determined by an a priori threshold of 70% of agreement and interquartile range (≤ 1 on criterion) to be included as essential or useful in the model of care framework. Experts agreed that improving access to care, optimal communication between stakeholders, education and training for health care workers, and home-based rehabilitation were essential for the model. Furthermore, task shifting and evidence-based practice were seen as fundamental for optimal care.

  9. Two Methods for Efficient Solution of the Hitting-Set Problem

    NASA Technical Reports Server (NTRS)

    Vatan, Farrokh; Fijany, Amir

    2005-01-01

    A paper addresses much of the same subject matter as that of Fast Algorithms for Model-Based Diagnosis (NPO-30582), which appears elsewhere in this issue of NASA Tech Briefs. However, in the paper, the emphasis is more on the hitting-set problem (also known as the transversal problem), which is well known among experts in combinatorics. The authors primary interest in the hitting-set problem lies in its connection to the diagnosis problem: it is a theorem of model-based diagnosis that in the set-theory representation of the components of a system, the minimal diagnoses of a system are the minimal hitting sets of the system. In the paper, the hitting-set problem (and, hence, the diagnosis problem) is translated from a combinatorial to a computational problem by mapping it onto the Boolean satisfiability and integer- programming problems. The paper goes on to describe developments nearly identical to those summarized in the cited companion NASA Tech Briefs article, including the utilization of Boolean-satisfiability and integer- programming techniques to reduce the computation time and/or memory needed to solve the hitting-set problem.

  10. Setting health research priorities using the CHNRI method: V. Quantitative properties of human collective knowledge

    PubMed Central

    Rudan, Igor; Yoshida, Sachiyo; Wazny, Kerri; Chan, Kit Yee; Cousens, Simon

    2016-01-01

    Introduction The CHNRI method for setting health research priorities has crowdsourcing as the major component. It uses the collective opinion of a group of experts to generate, assess and prioritize between many competing health research ideas. It is difficult to compare the accuracy of human individual and collective opinions in predicting uncertain future outcomes before the outcomes are known. However, this limitation does not apply to existing knowledge, which is an important component underlying opinion. In this paper, we report several experiments to explore the quantitative properties of human collective knowledge and discuss their relevance to the CHNRI method. Methods We conducted a series of experiments in groups of about 160 (range: 122–175) undergraduate Year 2 medical students to compare their collective knowledge to their individual knowledge. We asked them to answer 10 questions on each of the following: (i) an area in which they have a degree of expertise (undergraduate Year 1 medical curriculum); (ii) an area in which they likely have some knowledge (general knowledge); and (iii) an area in which they are not expected to have any knowledge (astronomy). We also presented them with 20 pairs of well–known celebrities and asked them to identify the older person of the pair. In all these experiments our goal was to examine how the collective answer compares to the distribution of students’ individual answers. Results When answering the questions in their own area of expertise, the collective answer (the median) was in the top 20.83% of the most accurate individual responses; in general knowledge, it was in the top 11.93%; and in an area with no expertise, the group answer was in the top 7.02%. However, the collective answer based on mean values fared much worse, ranging from top 75.60% to top 95.91%. Also, when confronted with guessing the older of the two celebrities, the collective response was correct in 18/20 cases (90%), while the 8 most

  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. An Unbiased Method To Build Benchmarking Sets for Ligand-Based Virtual Screening and its Application To GPCRs

    PubMed Central

    2015-01-01

    Benchmarking data sets have become common in recent years for the purpose of virtual screening, though the main focus had been placed on the structure-based virtual screening (SBVS) approaches. Due to the lack of crystal structures, there is great need for unbiased benchmarking sets to evaluate various ligand-based virtual screening (LBVS) methods for important drug targets such as G protein-coupled receptors (GPCRs). To date these ready-to-apply data sets for LBVS are fairly limited, and the direct usage of benchmarking sets designed for SBVS could bring the biases to the evaluation of LBVS. Herein, we propose an unbiased method to build benchmarking sets for LBVS and validate it on a multitude of GPCRs targets. To be more specific, our methods can (1) ensure chemical diversity of ligands, (2) maintain the physicochemical similarity between ligands and decoys, (3) make the decoys dissimilar in chemical topology to all ligands to avoid false negatives, and (4) maximize spatial random distribution of ligands and decoys. We evaluated the quality of our Unbiased Ligand Set (ULS) and Unbiased Decoy Set (UDS) using three common LBVS approaches, with Leave-One-Out (LOO) Cross-Validation (CV) and a metric of average AUC of the ROC curves. Our method has greatly reduced the “artificial enrichment” and “analogue bias” of a published GPCRs benchmarking set, i.e., GPCR Ligand Library (GLL)/GPCR Decoy Database (GDD). In addition, we addressed an important issue about the ratio of decoys per ligand and found that for a range of 30 to 100 it does not affect the quality of the benchmarking set, so we kept the original ratio of 39 from the GLL/GDD. PMID:24749745

  13. An unbiased method to build benchmarking sets for ligand-based virtual screening and its application to GPCRs.

    PubMed

    Xia, Jie; Jin, Hongwei; Liu, Zhenming; Zhang, Liangren; Wang, Xiang Simon

    2014-05-27

    Benchmarking data sets have become common in recent years for the purpose of virtual screening, though the main focus had been placed on the structure-based virtual screening (SBVS) approaches. Due to the lack of crystal structures, there is great need for unbiased benchmarking sets to evaluate various ligand-based virtual screening (LBVS) methods for important drug targets such as G protein-coupled receptors (GPCRs). To date these ready-to-apply data sets for LBVS are fairly limited, and the direct usage of benchmarking sets designed for SBVS could bring the biases to the evaluation of LBVS. Herein, we propose an unbiased method to build benchmarking sets for LBVS and validate it on a multitude of GPCRs targets. To be more specific, our methods can (1) ensure chemical diversity of ligands, (2) maintain the physicochemical similarity between ligands and decoys, (3) make the decoys dissimilar in chemical topology to all ligands to avoid false negatives, and (4) maximize spatial random distribution of ligands and decoys. We evaluated the quality of our Unbiased Ligand Set (ULS) and Unbiased Decoy Set (UDS) using three common LBVS approaches, with Leave-One-Out (LOO) Cross-Validation (CV) and a metric of average AUC of the ROC curves. Our method has greatly reduced the "artificial enrichment" and "analogue bias" of a published GPCRs benchmarking set, i.e., GPCR Ligand Library (GLL)/GPCR Decoy Database (GDD). In addition, we addressed an important issue about the ratio of decoys per ligand and found that for a range of 30 to 100 it does not affect the quality of the benchmarking set, so we kept the original ratio of 39 from the GLL/GDD.

  14. Electromagnetic sunscreen model: implementation and comparison between several methods: step-film model, differential method, Mie scattering, and scattering by a set of parallel cylinders.

    PubMed

    Lécureux, Marie; Enoch, Stefan; Deumié, Carole; Tayeb, Gérard

    2014-10-01

    Sunscreens protect from UV radiation, a carcinogen also responsible for sunburns and age-associated dryness. In order to anticipate the transmission of light through UV protection containing scattering particles, we implement electromagnetic models, using numerical methods for solving Maxwell's equations. After having our models validated, we compare several calculation methods: differential method, scattering by a set of parallel cylinders, or Mie scattering. The field of application and benefits of each method are studied and examples using the appropriate method are described.

  15. The Effects of Different Standard Setting Methods and the Composition of Borderline Groups: A Study within a Law Curriculum

    ERIC Educational Resources Information Center

    Dochy, Filip; Kyndt, Eva; Baeten, Marlies; Pottier, Sofie; Veestraeten, Marlies; Leuven, K. U.

    2009-01-01

    The aim of this study was to examine the effect of different standard setting methods on the size and composition of the borderline group, on the discrimination between different types of students and on the types of students passing with one method but failing with another. A total of 107 university students were classified into 4 different types…

  16. The Impact of Test Dimensionality, Common-Item Set Format, and Scale Linking Methods on Mixed-Format Test Equating

    ERIC Educational Resources Information Center

    Öztürk-Gübes, Nese; Kelecioglu, Hülya

    2016-01-01

    The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

  17. Analytic design method for optimal imaging: coupling three ray sets using two free-form lens profiles.

    PubMed

    Duerr, Fabian; Benítez, Pablo; Miñano, Juan C; Meuret, Youri; Thienpont, Hugo

    2012-02-27

    In this work, a new two-dimensional optics design method is proposed that enables the coupling of three ray sets with two lens surfaces. The method is especially important for optical systems designed for wide field of view and with clearly separated optical surfaces. Fermat's principle is used to deduce a set of functional differential equations fully describing the entire optical system. The presented general analytic solution makes it possible to calculate the lens profiles. Ray tracing results for calculated 15th order Taylor polynomials describing the lens profiles demonstrate excellent imaging performance and the versatility of this new analytic design method. PMID:22418364

  18. 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…

  19. "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…

  20. 'They can't report abuse, they can't move out. They are at the mercy of these men': exploring connections between intimate partner violence, gender and HIV in South African clinical settings.

    PubMed

    Sprague, Courtenay; Hatcher, Abigail M; Woollett, Nataly; Sommers, Theresa; Black, Vivian

    2016-01-01

    This qualitative study captured South African female health provider perspectives of intimate partner violence in female patients, gender norms and consequences for patients' health. Findings indicated female patients' health behaviours were predicated on sociocultural norms of submission to men's authority and economic dependence on their partners. Respondents described how men's preferences and health decision-making in clinics affected their patients' health. Adverse gender norms and gender inequalities affected women's opportunities to be healthy, contributing to HIV risk and undermining effective HIV management in this context. Some providers, seeking to deliver a standard of quality healthcare to their female patients, demonstrated a willingness to challenge patriarchal gender relations. Findings enhance understanding of how socially-sanctioned gender norms, intimate partner violence and HIV are synergistic, also reaffirming the need for integrated HIV-intimate partner violence responses in multi-sector national strategic plans. Health providers' intimate knowledge of the lived experiences of female patients with intimate partner violence and/or HIV deepens understanding of how adverse gender norms generate health risks for women in ways that may inform policy and clinical practice in South Africa and other high-HIV prevalence settings.

  1. 'They can't report abuse, they can't move out. They are at the mercy of these men': exploring connections between intimate partner violence, gender and HIV in South African clinical settings.

    PubMed

    Sprague, Courtenay; Hatcher, Abigail M; Woollett, Nataly; Sommers, Theresa; Black, Vivian

    2016-01-01

    This qualitative study captured South African female health provider perspectives of intimate partner violence in female patients, gender norms and consequences for patients' health. Findings indicated female patients' health behaviours were predicated on sociocultural norms of submission to men's authority and economic dependence on their partners. Respondents described how men's preferences and health decision-making in clinics affected their patients' health. Adverse gender norms and gender inequalities affected women's opportunities to be healthy, contributing to HIV risk and undermining effective HIV management in this context. Some providers, seeking to deliver a standard of quality healthcare to their female patients, demonstrated a willingness to challenge patriarchal gender relations. Findings enhance understanding of how socially-sanctioned gender norms, intimate partner violence and HIV are synergistic, also reaffirming the need for integrated HIV-intimate partner violence responses in multi-sector national strategic plans. Health providers' intimate knowledge of the lived experiences of female patients with intimate partner violence and/or HIV deepens understanding of how adverse gender norms generate health risks for women in ways that may inform policy and clinical practice in South Africa and other high-HIV prevalence settings. PMID:26505136

  2. On application of constitutional descriptors for merging of quinoxaline data sets using linear statistical methods.

    PubMed

    Ghosh, Payel; Vracko, Marjan; Chattopadhyay, Asis Kumar; Bagchi, Manish C

    2008-08-01

    The present paper is an attempt for unifying two different quinoxaline data sets with a wide range of substituents in 2, 3, 7, and 8 positions having excellent antitubercular activities with a view to developing robust and reliable structure-activity relationships. The merging has been performed for these two sets of quinoxaline 1,4-di-N-oxides derivatives comprising 29 and 18 compounds, respectively, on the basis of constitutional descriptors, which denotes the structural characterization of the molecules. Principal component analysis was performed to see the distribution of the compounds from two data sets for the constitutional descriptors. The distribution of compounds in score plot based on constitutional descriptors suggests unification of quinoxaline data sets which is useful for the model development. Outlier detection was performed from the standpoint of residual analysis of the partial least squares regression models. The superiority of the constitutional descriptors over other calculated molecular descriptors has been established from the standpoint of leave-one-out cross-validation technique associated with partial least squares regression analysis. Internal validation through the leave-many-out methodology was also performed with good results, assuring the stability of the models. The results obtained from linear partial least squares regression analysis lead to a statistically significant and robust quantitative structure-activity relationship modeling.

  3. ‘Peace’ and ‘life worthwhile’ as measures of spiritual well-being in African palliative care: a mixed-methods study

    PubMed Central

    2013-01-01

    Background Patients with incurable, progressive disease receiving palliative care in sub-Saharan Africa experience high levels of spiritual distress with a detrimental impact on their quality of life. Locally validated measurement tools are needed to identify patients’ spiritual needs and evaluate and improve spiritual care, but up to now such tools have been lacking in Africa. The African Palliative Care Association (APCA) African Palliative Outcome Scale (POS) contains two items relating to peace and life worthwhile. We aimed to determine the content and construct validity of these items as measures of spiritual wellbeing in African palliative care populations. Methods The study was conducted at five palliative care services, four in South Africa and one in Uganda. The mixed-methods study design involved: (1) cognitive interviews with 72 patients, analysed thematically to explore the items’ content validity, and (2) quantitative data collection (n = 285 patients) using the POS and the Spirit 8 to assess construct validity. Results (1) Peace was interpreted according to the themes ‘perception of self and world’, ‘relationship to others’, ‘spiritual beliefs’ and ‘health and healthcare’. Life worthwhile was interpreted in relation to ‘perception of self and world’, ‘relationship to others’ and ‘identity’. (2) Conceptual convergence and divergence were also evident in the quantitative data: there was moderate correlation between peace and Spirit 8 spiritual well-being (r = 0.46), but little correlation between life worthwhile and Spirit 8 spiritual well-being (r = 0.18) (both p < 0.001). Correlations with Spirit 8 items were weak to moderate. Conclusions Findings demonstrate the utility of POS items peace and life worthwhile as distinct but related measures of spiritual well-being in African palliative care. Peace and life worthwhile are brief and simple enough to be integrated into routine practice and can be used to

  4. A comparison of limit setting methods for the on-off problem

    NASA Astrophysics Data System (ADS)

    Rolke, Wolfgang A.

    2016-01-01

    We study the frequentist properties of confidence intervals found with various methods previously proposed for the On-Off problem. We derive explicit formulas for the limits and calculate the true coverage and the expected lengths of these methods.

  5. Illumination Sufficiency Survey Techniques: In-situ Measurements of Lighting System Performance and a User Preference Survey for Illuminance in an Off-Grid, African Setting

    SciTech Connect

    Alstone, Peter; Jacobson, Arne; Mills, Evan

    2010-08-26

    Efforts to promote rechargeable electric lighting as a replacement for fuel-based light sources in developing countries are typically predicated on the notion that lighting service levels can be maintained or improved while reducing the costs and environmental impacts of existing practices. However, the extremely low incomes of those who depend on fuel-based lighting create a need to balance the hypothetically possible or desirable levels of light with those that are sufficient and affordable. In a pilot study of four night vendors in Kenya, we document a field technique we developed to simultaneously measure the effectiveness of lighting service provided by a lighting system and conduct a survey of lighting service demand by end-users. We took gridded illuminance measurements across each vendor's working and selling area, with users indicating the sufficiency of light at each point. User light sources included a mix of kerosene-fueled hurricane lanterns, pressure lamps, and LED lanterns.We observed illuminance levels ranging from just above zero to 150 lux. The LED systems markedly improved the lighting service levels over those provided by kerosene-fueled hurricane lanterns. Users reported that the minimum acceptable threshold was about 2 lux. The results also indicated that the LED lamps in use by the subjects did not always provide sufficient illumination over the desired retail areas. Our sample size is much too small, however, to reach any conclusions about requirements in the broader population. Given the small number of subjects and very specific type of user, our results should be regarded as indicative rather than conclusive. We recommend replicating the method at larger scales and across a variety of user types and contexts. Policymakers should revisit the subject of recommended illuminance levels regularly as LED technology advances and the price/service balance point evolves.

  6. GRID-based three-dimensional pharmacophores II: PharmBench, a benchmark data set for evaluating pharmacophore elucidation methods.

    PubMed

    Cross, Simon; Ortuso, Francesco; Baroni, Massimo; Costa, Giosuè; Distinto, Simona; Moraca, Federica; Alcaro, Stefano; Cruciani, Gabriele

    2012-10-22

    To date, published pharmacophore elucidation approaches typically use a handful of data sets for validation: here, we have assembled a data set for 81 targets, containing 960 ligands aligned using their cocrystallized protein targets, to provide the experimental "gold standard". The two-dimensional structures are also assembled to remove conformational bias; an ideal method would be able to take these structures as input, find the common features, and reproduce the bioactive conformations and their alignments to correspond with the X-ray-determined gold standard alignments. Here we present this data set and describe three objective measures to evaluate performance: the ability to identify the bioactive conformation, the ability to identify and correctly align this conformation for 50% of the molecules in each data set, and the pharmacophoric field similarity. We have applied this validation methodology to our pharmacophore elucidation method FLAPpharm, that is published in the first paper of this series and discuss the limitations of the data set and objective success criteria. Starting from two-dimensional structures and producing unbiased models, FLAPpharm was able to identify the bioactive conformations for 67% of the ligands and also to produce successful models according to the second metric for 67% of the Pharmbench data sets. Inspection of the unsuccessful models highlighted the limitation of this root mean square (rms)-derived metric, since many were found to be pharmacophorically reasonable, increasing the overall success rate to 83%. The PharmBench data set is available at http://www.moldiscovery.com/PharmBench , along with a web service to enable users to score model alignments coming from external methods in the same way that we have presented here and, therefore, establishes a pharmacophore elucidation benchmark data set available to be used by the community.

  7. Difficulties Experienced in Setting and Achieving Goals by Participants of a Falls Prevention Programme: A Mixed-Methods Evaluation

    PubMed Central

    Mason, Wendy; Haines, Terry P.

    2014-01-01

    ABSTRACT Purpose: To evaluate the ability of participants of a falls prevention programme to set and achieve goals. Methods: The study used a prospective longitudinal design and a mixed-methods approach to data collection. Study participants were (1) 220 older adults participating in a 15-week combined exercise and education falls prevention programme and (2) 9 practitioners (3 home-care nurses, 5 community workers, and an exercise physiologist) involved in delivering the programme. Data from goal-setting forms were analyzed, and descriptive statistics were used to determine the number of appropriate goals set and achieved. Data were analyzed according to programme setting (home- or group-based) and whether or not participants were classified as being from a Culturally and Linguistically Diverse (CALD) background in the Australian context. Semi-structured interviews with programme practitioners were thematically analyzed. Results: A total of 144 respondents (n=75 CALD group, n=41 non-CALD group, n=6 CALD home, n=22 non-CALD home) set 178 goals. Only 101 (57%) goals could be evaluated according to achievement, because participants set goals that focused on health state instead of behaviour, set goals not relevant to falls prevention, used inappropriate constructs to measure goal achievement, and either did not review their goals or dropped out of the programme before goal review. Of these 101 goals, 64 were achieved. Practitioners described their own difficulties in understanding the process of setting health behaviour goals along with communication, cultural, and logistic difficulties. Conclusions: Both CALD and non-CALD participants and those participating in both group- and home-based programmes experienced difficulty in setting and achieving goals to facilitate behaviour change for falls prevention. Data suggest that home-based participants had more difficulty in setting goals than their group-based counterparts and, to a lesser extent, that CALD participants

  8. Patient goal setting as a method for program improvement/development in partial hospitalization programs.

    PubMed

    Gates, A

    1991-12-01

    Data were collected from a study of 49 patients in 1990 and 106 patients in 1991 admitted into Country View Treatment Center and Green Country Counseling Center. Country View is a 30-bed chemical dependency residential center operating under St. John Medical Center in Tulsa, Oklahoma. Green Country is an evening partial hospital chemical dependency program operating under St. John Medical Center in Tulsa, Oklahoma, The tools used in this study were the Country View Patient Self-Reporting Questionnaire, the global Rating Scale, and the Model of Recovering Alcoholics Behavior Stages and Goal Setting (Wing, 1990). These assessments were specifically designed to measure the patient's perceptions of goal setting and the patient's perspective on treatment outcome. The study outcome resulted in program improvement (Green Country evening partial hospital program) and the development of the Country View Substance Abuse Intermediate Link (SAIL) Program (day partial hospital). PMID:10170967

  9. Learning and applying new quality improvement methods to the school health setting.

    PubMed

    Elik, Laurel L

    2013-11-01

    A school health registered nurse identified medication administration documentation errors by unlicensed assistive personnel (UAP) in a system of school health clinics in an urban setting. This nurse applied the Lean Six Sigma Define, Measure, Analyze, Improve, Control process of improvement methodology to effectively improve the process. The UAP of medication administration documentation error rate improved from 68% to 35%. This methodology may be used by school nurses to collaboratively look at ways to improve processes at the point of care.

  10. It Takes a Village: A Mixed Method Analysis of Inner Setting Variables and Dialectical Behavior Therapy Implementation

    PubMed Central

    Ditty, Matthew S.; Landes, Sara J.; Doyle, Andrea; Beidas, Rinad S.

    2014-01-01

    Guided by the Consolidated Framework for Implementation Research (CFIR), this mixed method study explored the relationship between inner setting variables and Dialectical Behavior Therapy (DBT) implementation. Intensively trained DBT clinicians completed an online quantitative survey (n = 79) and a subset were sequentially interviewed using qualitative methods (n = 20) to identify relationships between inner setting variables and DBT implementation. Four interpersonal variables - team cohesion, team communication, team climate, and supervision - were correlated with the quantity of DBT elements implemented. Qualitative themes corroborated these findings. Additional variables were connected to implementation by either quantitative or qualitative findings, but not both. PMID:25315183

  11. LEGO: a novel method for gene set over-representation analysis by incorporating network-based gene weights.

    PubMed

    Dong, Xinran; Hao, Yun; Wang, Xiao; Tian, Weidong

    2016-01-11

    Pathway or gene set over-representation analysis (ORA) has become a routine task in functional genomics studies. However, currently widely used ORA tools employ statistical methods such as Fisher's exact test that reduce a pathway into a list of genes, ignoring the constitutive functional non-equivalent roles of genes and the complex gene-gene interactions. Here, we develop a novel method named LEGO (functional Link Enrichment of Gene Ontology or gene sets) that takes into consideration these two types of information by incorporating network-based gene weights in ORA analysis. In three benchmarks, LEGO achieves better performance than Fisher and three other network-based methods. To further evaluate LEGO's usefulness, we compare LEGO with five gene expression-based and three pathway topology-based methods using a benchmark of 34 disease gene expression datasets compiled by a recent publication, and show that LEGO is among the top-ranked methods in terms of both sensitivity and prioritization for detecting target KEGG pathways. In addition, we develop a cluster-and-filter approach to reduce the redundancy among the enriched gene sets, making the results more interpretable to biologists. Finally, we apply LEGO to two lists of autism genes, and identify relevant gene sets to autism that could not be found by Fisher.

  12. Simulation of Heterogeneous Atom Probe Tip Shapes Evolution during Field Evaporation Using a Level Set Method and Different Evaporation Models

    SciTech Connect

    Xu, Zhijie; Li, Dongsheng; Xu, Wei; Devaraj, Arun; Colby, Robert J.; Thevuthasan, Suntharampillai; Geiser, B. P.; Larson, David J.

    2015-04-01

    In atom probe tomography (APT), accurate reconstruction of the spatial positions of field evaporated ions from measured detector patterns depends upon a correct understanding of the dynamic tip shape evolution and evaporation laws of component atoms. Artifacts in APT reconstructions of heterogeneous materials can be attributed to the assumption of homogeneous evaporation of all the elements in the material in addition to the assumption of a steady state hemispherical dynamic tip shape evolution. A level set method based specimen shape evolution model is developed in this study to simulate the evaporation of synthetic layered-structured APT tips. The simulation results of the shape evolution by the level set model qualitatively agree with the finite element method and the literature data using the finite difference method. The asymmetric evolving shape predicted by the level set model demonstrates the complex evaporation behavior of heterogeneous tip and the interface curvature can potentially lead to the artifacts in the APT reconstruction of such materials. Compared with other APT simulation methods, the new method provides smoother interface representation with the aid of the intrinsic sub-grid accuracy. Two evaporation models (linear and exponential evaporation laws) are implemented in the level set simulations and the effect of evaporation laws on the tip shape evolution is also presented.

  13. A Conceptual Framework for a Psychometric Theory for Standard Setting with Examples of Its Use for Evaluating the Functioning of Two Standard Setting Methods

    ERIC Educational Resources Information Center

    Reckase, Mark D.

    2006-01-01

    A conceptual framework is proposed for a psychometric theory of standard setting. The framework suggests that participants in a standard setting process (panelists) develop an internal, intended standard as a result of training and the participant's background. The goal of a standard setting process is to convert panelists' intended standards to…

  14. Effects of the method of apatite seed crystals addition on setting reaction of α-tricalcium phosphate based apatite cement.

    PubMed

    Tsuru, Kanji; Ruslin; Maruta, Michito; Matsuya, Shigeki; Ishikawa, Kunio

    2015-10-01

    Appropriate setting time is an important parameter that determines the effectiveness of apatite cement (AC) for clinical application, given the issues of crystalline inflammatory response phenomena if AC fails to set. To this end, the present study analyzes the effects of the method of apatite seed crystals addition on the setting reaction of α-tricalcium phosphate (α-TCP) based AC. Two ACs, both consisting of α-TCP and calcium deficient hydroxyapatite (cdHAp), were analyzed in this study. In one AC, cdHAp was added externally to α-TCP and this AC was abbreviated as AC(EA). In the other AC, α-TCP was partially hydrolyzed to form cdHAp on the surface of α-TCP. This AC was referred to as AC(PH). Results indicate a decrease in the setting time of both ACs with the addition of cdHAp. Among them, for the given amount of added cdHAp, AC(PH) showed relatively shorter setting time than AC(EA). Besides, the mechanical strength of the set AC(PH) was also higher than that of set AC(EA). These properties of AC(PH) were attributed to the predominant crystal growth of cdHAp in the vicinity of the α-TCP particle surface. Accordingly, it can be concluded that the partial hydrolysis of α-TCP may be a better approach to add low crystalline cdHAp onto α-TCP based AC.

  15. Mining unusual and rare stellar spectra from large spectroscopic survey data sets using the outlier-detection method

    NASA Astrophysics Data System (ADS)

    Wei, Peng; Luo, Ali; Li, Yinbi; Pan, Jingchang; Tu, Liangping; Jiang, Bin; Kong, Xiao; Shi, Zhixin; Yi, Zhenping; Wang, Fengfei; Liu, Jie; Zhao, Yongheng

    2013-05-01

    The large number of spectra obtained from sky surveys such as the Sloan Digital Sky Survey (SDSS) and the survey executed by the Large sky Area Multi-Object fibre Spectroscopic Telescope (LAMOST, also called GuoShouJing Telescope) provide us with opportunities to search for peculiar or even unknown types of spectra. In response to the limitations of existing methods, a novel outlier-mining method, the Monte Carlo Local Outlier Factor (MCLOF), is proposed in this paper, which can be used to highlight unusual and rare spectra from large spectroscopic survey data sets. The MCLOF method exposes outliers automatically and efficiently by marking each spectrum with a number, i.e. using outlier index as a flag for an unusual and rare spectrum. The Local Outlier Factor (LOF) represents how unusual and rare a spectrum is compared with other spectra and the Monte Carlo method is used to compute the global LOF for each spectrum by randomly selecting samples in each independent iteration. Our MCLOF method is applied to over half a million stellar spectra (classified as STAR by the SDSS Pipeline) from the SDSS data release 8 (DR8) and a total of 37 033 spectra are selected as outliers with signal-to-noise ratio (S/N) ≥ 3 and outlier index ≥0.85. Some of these outliers are shown to be binary stars, emission-line stars, carbon stars and stars with unusual continuum. The results show that our proposed method can efficiently highlight these unusual spectra from the survey data sets. In addition, some relatively rare and interesting spectra are selected, indicating that the proposed method can also be used to mine rare, even unknown, spectra. The proposed method can be applicable not only to spectral survey data sets but also to other types of survey data sets. The spectra of all peculiar objects selected by our MCLOF method are available from a user-friendly website: http://sciwiki.lamost.org/Miningdr8/.

  16. Simulating collisions of droplets with walls and films using a level set method

    NASA Astrophysics Data System (ADS)

    Kwon, Tae-Jun

    A coupled level set and Marker and Cell is developed for computing axisymmetric, incompressible, and immiscible two-phase flows. Instead of using marker particles to track the free surface, the level set function is employed to "capture" the complex interfacial structure. An iterative process is devised in order to maintain the level set function as the signed distance from the interface. As a base line case, the two-phase fluid code is implemented for simulating zero gravity capillary oscillations of liquid droplet in order to validate its capability to handle surface tension effects. Initially deformed shapes of the second spherical harmonics are to oscillate and the simulation results are compared with linearized analytic solutions as well as other numerical calculations. A viscous damping towards an equilibrium sphere and capillary oscillation-period variations are investigated. Axisymmetric steady rising bubbles in an unbounded quiescent viscous liquid are simulated for a validation of code's ability in buoyancy driven deformations and stable breakup processes. The simulation results show a consistency with other numerical results for a high Weber number cases. It should be pointed out that no additional treatment is necessary to handle bubble breakups. An impact of a liquid droplet onto solid surface and/or shallow liquid layer has been simulated and compared with corresponding experimental data. Case studies on the radial extension versus variable Weber numbers show good agreements with experimental observation. Drop collisions onto shallow liquid layer are chosen for splash simulations. The effects of layer thickness are studied by analyzing radial extension and elevation of the splash rim. Drop impingement on deep pool is also examined on purpose to simulate a crater and a central jet. It is found that there exists a criterion to distinguish between the splashing and the deposition events in terms of a single impact parameter. A simple dimensional analysis

  17. Analyzing Empirical Evaluations of Non-Experimental Methods in Field Settings

    ERIC Educational Resources Information Center

    Steiner, Peter M.; Wong, Vivian

    2016-01-01

    Despite recent emphasis on the use of randomized control trials (RCTs) for evaluating education interventions, in most areas of education research, observational methods remain the dominant approach for assessing program effects. Over the last three decades, the within-study comparison (WSC) design has emerged as a method for evaluating the…

  18. Ab initio modeling of carbohydrates: on the proper selection of computational methods and basis sets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the development of faster computer hardware and quantum mechanical software it has become more feasible to study large carbohydrate molecules via quantum mechanical methods. In the past, studies of carbohydrates were restricted to empirical/semiempirical methods and Hartree Fock. In the last ...

  19. How to select basis sets and computational methods for carbohydrate modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the last decade there have been significant improvements in computer hardware but also in development of quantum mechanical methods. This makes it more feasible to study large carbohydrate molecules via quantum mechanical methods whereas in the past studies of carbohydrates were restricted to em...

  20. Level set methods to compute minimal surfaces in a medium with exclusions (voids).

    SciTech Connect

    Walsh, Timothy Francis; Chopp, David; Torres, Monica

    2003-06-01

    In T1, periodic minimal surfaces in a medium with exclusions (voids) are constructed and in this paper we present two algorithms for computing these minimal surfaces. The two algorithms use evolution of level sets by mean curvature. The first algorithm solves the governing nonlinear PDE directly and enforces numerically an orthogonality condition that the surfaces satisfy when they meet the boundaries of the exclusions. The second algorithm involves h-adaptive finite element approximations of a linear convection-diffusion equation, which has been shown to linearize the governing nonlinear PDE for weighted mean curvature flow.

  1. Comparison between hemisphere comparison method and dipole-fitting method in tracing the anisotropic expansion of the Universe use the Union2 data set

    NASA Astrophysics Data System (ADS)

    Chang, Zhe; Lin, Hai-Nan

    2015-01-01

    Type Ia supernovae (SNe Ia) are often used as the standard candles to probe the anisotropic expansion of the Universe. In this paper, we make a comprehensive comparison between the hemisphere comparison (HC) method and dipole-fitting (DF) method in searching for the cosmological preferred direction using the Union2 data set, a compilation of 557 well-calibrated SNe Ia. We find that the directions of the faintest SNe Ia derived from these two methods are approximately opposite. Monte Carlo simulations show that the results of the HC method strongly depend on the distribution of the data points in the sky. The coincidence that the HC method and DF method give two completely opposite directions may be due to the extremely non-uniform distribution of the Union2 data set.

  2. The Expanded FindCore Method for Identification of a Core Atom Set for Assessment of Protein Structure Prediction

    PubMed Central

    Snyder, David A.; Grullon, Jennifer; Huang, Yuanpeng J.; Tejero, Roberto; Montelione, Gaetano T.

    2014-01-01

    Maximizing the scientific impact of NMR-based structure determination requires robust and statistically sound methods for assessing the precision of NMR-derived structures. In particular, a method to define a core atom set for calculating superimpositions and validating structure predictions is critical to the use of NMR-derived structures as targets in the CASP competition. FindCore (D.A. Snyder and G.T. Montelione PROTEINS 2005;59:673–686) is a superimposition independent method for identifying a core atom set, and partitioning that set into domains. However, as FindCore optimizes superimposition by sensitively excluding not-well-defined atoms, the FindCore core may not comprise all atoms suitable for use in certain applications of NMR structures, including the CASP assessment process. Adapting the FindCore approach to assess predicted models against experimental NMR structures in CASP10 required modification of the FindCore method. This paper describes conventions and a standard protocol to calculate an “Expanded FindCore” atom set suitable for validation and application in biological and biophysical contexts. A key application of the Expanded FindCore method is to identify a core set of atoms in the experimental NMR structure for which it makes sense to validate predicted protein structure models. We demonstrate the application of this Expanded FindCore method in characterizing well-defined regions of 18 NMR-derived CASP10 target structures. The Expanded FindCore protocol defines “expanded core atom sets” that match an expert’s intuition of which parts of the structure are sufficiently well-defined to use in assessing CASP model predictions. We also illustrate the impact of this analysis on the CASP GDT assessment scores. PMID:24327305

  3. Applications of the POCS inversion method to interpolating topography and other geophysical fields. [Projection Onto Convex Sets

    SciTech Connect

    Menke, W. )

    1991-03-01

    The author applies the method of Projection Onto Convex Sets (POCS) to the problem of solving geophysical inverse problems. The advantage of this iterative method is its flexibility in handling non-linear equality and inequality constraints, including constraints on the spectrum of unknown functions. He gives examples of using POCS to interpolate topographic profiles, topographic maps, and the physical properties of the earth between well logs.

  4. Teacher Training in Norm Setting Approaches to Drug Education: A Pilot Study Comparing Standard and Video-Enhanced Methods

    ERIC Educational Resources Information Center

    Dusenbury, Linda A.; Hansen, William B.; Giles, Steven M.

    2003-01-01

    Norm setting has been shown to be a crucial element of effective drug education. The purpose of this study was to examine the degree to which a videotape describing concepts and methods for establishing positive norms would enhance standard training. Participants included 35 teachers and 64 health education students who were randomly assigned to…

  5. Using Narrative as a Data Source and Analytic Method to Investigate Learning Outside of Traditional School Settings with Diverse Youth

    ERIC Educational Resources Information Center

    Martell, Sandra Toro; Antrop-Gonzalez, Rene

    2008-01-01

    Narrative is used to describe and understand how people construct meaning of their lives and experiences and how they think about their own and others' identities. We examined narrative as both data source and method of analysis for investigating learning in non-traditional school settings with students from diverse socio-economic status and…

  6. A Method Defining a Limited Set of Character-Strings with Maximal Coverage of a Sample of Text.

    ERIC Educational Resources Information Center

    Hultgren, Jan; Larsson, Rolf

    This is a progress report on a project attempting to design a system of compacting text for storage appropriate to disc oriented demand searching. After noting a number of previously designed methods of compression, it offers a tentative solution which couples a dictionary of most frequent character-strings with a set of variable-length codes. The…

  7. The mouse attentional set-shifting task: A method for assaying successful cognitive aging?

    PubMed Central

    YOUNG, Jared W; POWELL, Susan B; GEYER, Mark A; JESTE, Dilip V; RISBROUGH, Victoria B

    2009-01-01

    Humans exhibit considerable variance in cognitive decline with age, with some exhibiting little disruption while others become significantly impaired. In aged rodents, individual differences in spatial memory have been used to identify putative compensatory mechanisms underlying successful hippocampal aging. However, there are few parallel rodent models of cognitive decline in frontal cortex-mediated functions. We tested the hypothesis that, like aged humans, aged mice would exhibit greater variance in executive function measures compared to young mice. We examined the performance of young and aged C57BL/6N mice in the attentional set-shifting task. While young and old mice did not differ on trials to criterion performance, aged mice exhibited significantly greater variance in mean correct latency – selective to the extradimensional shifting stage – compared to their younger counterparts. Thus this task may be used to identify mechanisms underlying individual differences in decline of frontal-mediated performances with age. PMID:20498348

  8. Two Methods for Engaging with the Community in Setting Priorities for Child Health Research: Who Engages?

    PubMed Central

    McKenzie, Anne; Hancock, Kirsten; Haines, Hayley; Christensen, Daniel; Zubrick, Stephen R.

    2015-01-01

    Objective The aims of this study were to assess participatory methods for obtaining community views on child health research. Background Community participation in research is recognised as an important part of the research process; however, there has been inconsistency in its implementation and application in Australia. The Western Australian Telethon Kids Institute Participation Program employs a range of methods for fostering active involvement of community members in its research. These include public discussion forums, called Community Conversations. While participation levels are good, the attendees represent only a sub-section of the Western Australian population. Therefore, we conducted a telephone survey of randomly selected households to evaluate its effectiveness in eliciting views from a broader cross-section of the community about our research agenda and community participation in research, and whether the participants would be representative of the general population. We also conducted two Conversations, comparing the survey as a recruitment tool and normal methods using the Participation Program. Results While the telephone survey was a good method for eliciting community views about research, there were marked differences in the profile of study participants compared to the general population (e.g. 78% vs 50% females). With a 26% response rate, the telephone survey was also more expensive than a Community Conversation. The cold calling approach proved an unsuccessful recruitment method, with only two out of a possible 816 telephone respondents attending a Conversation. Conclusion While the results showed that both of the methods produced useful input for our research program, we could not conclude that either method gained input that was representative of the entire community. The Conversations were relatively low-cost and provided more in-depth information about one subject, whereas the telephone survey provided information across a greater range

  9. Alternative Method for the Mass Rearing of Lutzomyia (Lutzomyia) cruzi (Diptera: Psychodidae) in a Laboratory Setting.

    PubMed

    Oliveira, E F; Fernandes, W S; Oshiro, E T; Oliveira, A G; Galati, E A B

    2015-09-01

    The understanding of the transmission dynamics of Leishmania spp. Ross as well as the epidemiology and spread of leishmaniasis is related to parasite-vector-host interactions. These interactions can be studied using specimens of a sand fly population reared in the laboratory, exposing individuals to experimental infection for the investigation of vector competence and parameters of the vectorial capacity of the species. The present study sought to describe an alternative method for the implantation of a Lutzomyia (Lutzomyia) cruzi colony with wild specimens captured in the municipality of Corumbá, Brazil. With Method 1, engorged females were individualized for oviposition. The eggs were transferred to an acrylic petri dish with a layer of plaster on the bottom, on which food was placed after hatching of the first larvae. With Method 2, females were kept in groups for oviposition in containers, in which soil and food were placed on their bottom for the larvae. In addition, the exposure time of the larvae to light was reduced in comparison with Method 1. With Method 2, a significantly greater number of specimens of Lu. cruzi was obtained. The ratio between the number of emerged adults and the females followed for oviposition was 0.42 with Method 1 and 2.75 with Method 2. The optimization of the rearing conditions for Lu. cruzi will enable the establishment of a colony providing a sufficient number of specimens to develop experimental infection by Leishmania as well as vectorial competence and some parameters of the vectorial capacity of this sand fly.

  10. 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 ...

  11. Electromagnetic sunscreen model: implementation and comparison between several methods: step-film model, differential method, Mie scattering, and scattering by a set of parallel cylinders.

    PubMed

    Lécureux, Marie; Enoch, Stefan; Deumié, Carole; Tayeb, Gérard

    2014-10-01

    Sunscreens protect from UV radiation, a carcinogen also responsible for sunburns and age-associated dryness. In order to anticipate the transmission of light through UV protection containing scattering particles, we implement electromagnetic models, using numerical methods for solving Maxwell's equations. After having our models validated, we compare several calculation methods: differential method, scattering by a set of parallel cylinders, or Mie scattering. The field of application and benefits of each method are studied and examples using the appropriate method are described. PMID:25322243

  12. Evaluating the ability of Bayesian clustering methods to detect hybridization and introgression using an empirical red wolf data set.

    PubMed

    Bohling, Justin H; Adams, Jennifer R; Waits, Lisette P

    2013-01-01

    Bayesian clustering methods have emerged as a popular tool for assessing hybridization using genetic markers. Simulation studies have shown these methods perform well under certain conditions; however, these methods have not been evaluated using empirical data sets with individuals of known ancestry. We evaluated the performance of two clustering programs, baps and structure, with genetic data from a reintroduced red wolf (Canis rufus) population in North Carolina, USA. Red wolves hybridize with coyotes (C. latrans), and a single hybridization event resulted in introgression of coyote genes into the red wolf population. A detailed pedigree has been reconstructed for the wild red wolf population that includes individuals of 50-100% red wolf ancestry, providing an ideal case study for evaluating the ability of these methods to estimate admixture. Using 17 microsatellite loci, we tested the programs using different training set compositions and varying numbers of loci. structure was more likely than baps to detect an admixed genotype and correctly estimate an individual's true ancestry composition. However, structure was more likely to misclassify a pure individual as a hybrid. Both programs were outperformed by a maximum-likelihood-based test designed specifically for this system, which never misclassified a hybrid (50-75% red wolf) as a red wolf or vice versa. Training set composition and the number of loci both had an impact on accuracy but their relative importance varied depending on the program. Our findings demonstrate the importance of evaluating methods used for detecting admixture in the context of endangered species management. PMID:23163531

  13. Evaluation of Accuracy and Reliability of the Six Ensemble Methods Using 198 Sets of Pseudo-Simulation Data

    NASA Astrophysics Data System (ADS)

    Suh, M. S.; Oh, S. G.

    2014-12-01

    The accuracy and reliability of the six ensemble methods were evaluated according to simulation skills, training period, and ensemble members, using 198 sets of pseudo-simulation data (PSD) generated by considering the simulation characteristics of regional climate models. The PSD sets were classified into 18 categories according to the relative magnitude of bias, variance ratio, and correlation coefficient, where each category had 11 sets with 50 samples. The ensemble methods used were as follows: equal weighted averaging with(out) bias correction (EWA_W(N)BC), weighted ensemble averaging based on root mean square errors and correlation (WEA_RAC), WEA based on the Taylor score (WEA_Tay), WEA based on reliability (WEA_REA), and multivariate linear regression (Mul_Reg). The weighted ensemble methods showed better projection skills in terms of accuracy and reliability than non-weighted methods, in particular, for the PSD categories having systematic biases and various correlation coefficients. In general, WEA_Tay, WEA_REA and WEA_RAC showed superior skills in terms of accuracy and reliability, regardless of the PSD categories, training periods, and ensemble numbers. The evaluation results showed that WEA_Tay and WEA_RAC are applicable even for simulation data with systematic biases, a short training period, and a small number of members. However, the EWA_NBC showed a comparable projection skill with the other methods only in the certain categories with unsystematic biases.

  14. Evaluating the ability of Bayesian clustering methods to detect hybridization and introgression using an empirical red wolf data set.

    PubMed

    Bohling, Justin H; Adams, Jennifer R; Waits, Lisette P

    2013-01-01

    Bayesian clustering methods have emerged as a popular tool for assessing hybridization using genetic markers. Simulation studies have shown these methods perform well under certain conditions; however, these methods have not been evaluated using empirical data sets with individuals of known ancestry. We evaluated the performance of two clustering programs, baps and structure, with genetic data from a reintroduced red wolf (Canis rufus) population in North Carolina, USA. Red wolves hybridize with coyotes (C. latrans), and a single hybridization event resulted in introgression of coyote genes into the red wolf population. A detailed pedigree has been reconstructed for the wild red wolf population that includes individuals of 50-100% red wolf ancestry, providing an ideal case study for evaluating the ability of these methods to estimate admixture. Using 17 microsatellite loci, we tested the programs using different training set compositions and varying numbers of loci. structure was more likely than baps to detect an admixed genotype and correctly estimate an individual's true ancestry composition. However, structure was more likely to misclassify a pure individual as a hybrid. Both programs were outperformed by a maximum-likelihood-based test designed specifically for this system, which never misclassified a hybrid (50-75% red wolf) as a red wolf or vice versa. Training set composition and the number of loci both had an impact on accuracy but their relative importance varied depending on the program. Our findings demonstrate the importance of evaluating methods used for detecting admixture in the context of endangered species management.

  15. Sparse field level set method for non-convex Hamiltonians in 3D plasma etching profile simulations

    NASA Astrophysics Data System (ADS)

    Radjenović, Branislav; Lee, Jae Koo; Radmilović-Radjenović, Marija

    2006-01-01

    Level set method [S. Osher, J. Sethian, J. Comput. Phys. 79 (1988) 12] is a highly robust and accurate computational technique for tracking moving interfaces in various application domains. It originates from the idea to view the moving front as a particular level set of a higher dimensional function, so the topological merging and breaking, sharp gradients and cusps can form naturally, and the effects of curvature can be easily incorporated. The resulting equations, describing interface surface evolution, are of Hamilton-Jacobi type and they are solved using techniques developed for hyperbolic equations. In this paper we describe an extension of the sparse field method for solving level set equations in the case of non-convex Hamiltonians, which are common in the simulations of the profile surface evolution during plasma etching and deposition processes. Sparse field method itself, developed by Whitaker [R. Whitaker, Internat. J. Comput. Vision 29 (3) (1998) 203] and broadly used in image processing community, is an alternative to the usual combination of narrow band and fast marching procedures for the computationally effective solving of level set equations. The developed procedure is applied to the simulations of 3D feature profile surface evolution during plasma etching process, that include the effects of ion enhanced chemical etching and physical sputtering, which are the primary causes of the Hamiltonian non-convexity.

  16. Extension of the basis set of linearized augmented plane wave (LAPW) method by using supplemented tight binding basis functions

    NASA Astrophysics Data System (ADS)

    Nikolaev, A. V.; Lamoen, D.; Partoens, B.

    2016-07-01

    In order to increase the accuracy of the linearized augmented plane wave (LAPW) method, we present a new approach where the plane wave basis function is augmented by two different atomic radial components constructed at two different linearization energies corresponding to two different electron bands (or energy windows). We demonstrate that this case can be reduced to the standard treatment within the LAPW paradigm where the usual basis set is enriched by the basis functions of the tight binding type, which go to zero with zero derivative at the sphere boundary. We show that the task is closely related with the problem of extended core states which is currently solved by applying the LAPW method with local orbitals (LAPW+LO). In comparison with LAPW+LO, the number of supplemented basis functions in our approach is doubled, which opens up a new channel for the extension of the LAPW and LAPW+LO basis sets. The appearance of new supplemented basis functions absent in the LAPW+LO treatment is closely related with the existence of the u ˙ l -component in the canonical LAPW method. We discuss properties of additional tight binding basis functions and apply the extended basis set for computation of electron energy bands of lanthanum (face and body centered structures) and hexagonal close packed lattice of cadmium. We demonstrate that the new treatment gives lower total energies in comparison with both canonical LAPW and LAPW+LO, with the energy difference more pronounced for intermediate and poor LAPW basis sets.

  17. Method for detecting the signature of noise-induced structures in spatiotemporal data sets: an application to excitable media

    NASA Astrophysics Data System (ADS)

    Huett, Marc-Thorsten

    2003-05-01

    We formulate mathematical tools for analyzing spatiotemporal data sets. The tools are based on nearest-neighbor considerations similar to cellular automata. One of the analysis tools allows for reconstructing the noise intensity in a data set and is an appropriate method for detecting a variety of noise-induced phenomena in spatiotemporal data. The functioning of these methods is illustrated on sample data generated with the forest fire model and with networks of nonlinear oscillators. It is seen that these methods allow the characterization of spatiotemporal stochastic resonance (STSR) in experimental data. Application of these tools to biological spatiotemporal patterns is discussed. For one specific example, the slime mold Dictyostelium discoideum, it is seen, how transitions between different patterns are clearly marked by changes in the spatiotemporal observables.

  18. Teaching to Think: Applying the Socratic Method outside the Law School Setting

    ERIC Educational Resources Information Center

    Peterson, Evan

    2009-01-01

    An active learning process has the potential to provide educational benefits above-and-beyond what they might receive from more traditional, passive approaches. The Socratic Method is a unique approach to passive learning that facilitates critical thinking, open-mindedness, and teamwork. By imposing a series of guided questions to students, an…

  19. Impact of Learning Theory Methods on Undergraduate Retention and Application of Software in a Studio Setting

    ERIC Educational Resources Information Center

    Gomboc-Turyan, Julie L.

    2012-01-01

    The transition from an academic atmosphere to the professional world is an important step in a college student's life. The use of traditional teaching methods has been the subject of ongoing research into how well they prepare students for this transition. The evolution of technology and the state of the nation's economy continually…

  20. Peptide dynamics by molecular dynamics simulation and diffusion theory method with improved basis sets

    NASA Astrophysics Data System (ADS)

    Hsu, Po Jen; Lai, S. K.; Rapallo, Arnaldo

    2014-03-01

    Improved basis sets for the study of polymer dynamics by means of the diffusion theory, and tests on a melt of cis-1,4-polyisoprene decamers, and a toluene solution of a 71-mer syndiotactic trans-1,2-polypentadiene were presented recently [R. Gaspari and A. Rapallo, J. Chem. Phys. 128, 244109 (2008)]. The proposed hybrid basis approach (HBA) combined two techniques, the long time sorting procedure and the maximum correlation approximation. The HBA takes advantage of the strength of these two techniques, and its basis sets proved to be very effective and computationally convenient in describing both local and global dynamics in cases of flexible synthetic polymers where the repeating unit is a unique type of monomer. The question then arises if the same efficacy continues when the HBA is applied to polymers of different monomers, variable local stiffness along the chain and with longer persistence length, which have different local and global dynamical properties against the above-mentioned systems. Important examples of this kind of molecular chains are the proteins, so that a fragment of the protein transthyretin is chosen as the system of the present study. This peptide corresponds to a sequence that is structured in β-sheets of the protein and is located on the surface of the channel with thyroxin. The protein transthyretin forms amyloid fibrils in vivo, whereas the peptide fragment has been shown [C. P. Jaroniec, C. E. MacPhee, N. S. Astrof, C. M. Dobson, and R. G. Griffin, Proc. Natl. Acad. Sci. U.S.A. 99, 16748 (2002)] to form amyloid fibrils in vitro in extended β-sheet conformations. For these reasons the latter is given considerable attention in the literature and studied also as an isolated fragment in water solution where both experimental and theoretical efforts have indicated the propensity of the system to form β turns or α helices, but is otherwise predominantly unstructured. Differing from previous computational studies that employed implicit

  1. Peptide dynamics by molecular dynamics simulation and diffusion theory method with improved basis sets

    SciTech Connect

    Hsu, Po Jen; Lai, S. K.; Rapallo, Arnaldo

    2014-03-14

    Improved basis sets for the study of polymer dynamics by means of the diffusion theory, and tests on a melt of cis-1,4-polyisoprene decamers, and a toluene solution of a 71-mer syndiotactic trans-1,2-polypentadiene were presented recently [R. Gaspari and A. Rapallo, J. Chem. Phys. 128, 244109 (2008)]. The proposed hybrid basis approach (HBA) combined two techniques, the long time sorting procedure and the maximum correlation approximation. The HBA takes advantage of the strength of these two techniques, and its basis sets proved to be very effective and computationally convenient in describing both local and global dynamics in cases of flexible synthetic polymers where the repeating unit is a unique type of monomer. The question then arises if the same efficacy continues when the HBA is applied to polymers of different monomers, variable local stiffness along the chain and with longer persistence length, which have different local and global dynamical properties against the above-mentioned systems. Important examples of this kind of molecular chains are the proteins, so that a fragment of the protein transthyretin is chosen as the system of the present study. This peptide corresponds to a sequence that is structured in β-sheets of the protein and is located on the surface of the channel with thyroxin. The protein transthyretin forms amyloid fibrils in vivo, whereas the peptide fragment has been shown [C. P. Jaroniec, C. E. MacPhee, N. S. Astrof, C. M. Dobson, and R. G. Griffin, Proc. Natl. Acad. Sci. U.S.A. 99, 16748 (2002)] to form amyloid fibrils in vitro in extended β-sheet conformations. For these reasons the latter is given considerable attention in the literature and studied also as an isolated fragment in water solution where both experimental and theoretical efforts have indicated the propensity of the system to form β turns or α helices, but is otherwise predominantly unstructured. Differing from previous computational studies that employed implicit

  2. Peptide dynamics by molecular dynamics simulation and diffusion theory method with improved basis sets.

    PubMed

    Hsu, Po Jen; Lai, S K; Rapallo, Arnaldo

    2014-03-14

    Improved basis sets for the study of polymer dynamics by means of the diffusion theory, and tests on a melt of cis-1,4-polyisoprene decamers, and a toluene solution of a 71-mer syndiotactic trans-1,2-polypentadiene were presented recently [R. Gaspari and A. Rapallo, J. Chem. Phys. 128, 244109 (2008)]. The proposed hybrid basis approach (HBA) combined two techniques, the long time sorting procedure and the maximum correlation approximation. The HBA takes advantage of the strength of these two techniques, and its basis sets proved to be very effective and computationally convenient in describing both local and global dynamics in cases of flexible synthetic polymers where the repeating unit is a unique type of monomer. The question then arises if the same efficacy continues when the HBA is applied to polymers of different monomers, variable local stiffness along the chain and with longer persistence length, which have different local and global dynamical properties against the above-mentioned systems. Important examples of this kind of molecular chains are the proteins, so that a fragment of the protein transthyretin is chosen as the system of the present study. This peptide corresponds to a sequence that is structured in β-sheets of the protein and is located on the surface of the channel with thyroxin. The protein transthyretin forms amyloid fibrils in vivo, whereas the peptide fragment has been shown [C. P. Jaroniec, C. E. MacPhee, N. S. Astrof, C. M. Dobson, and R. G. Griffin, Proc. Natl. Acad. Sci. U.S.A. 99, 16748 (2002)] to form amyloid fibrils in vitro in extended β-sheet conformations. For these reasons the latter is given considerable attention in the literature and studied also as an isolated fragment in water solution where both experimental and theoretical efforts have indicated the propensity of the system to form β turns or α helices, but is otherwise predominantly unstructured. Differing from previous computational studies that employed implicit

  3. A new method for automatic synthesis of tolerances for complex assemblies based on polychromatic sets

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Li, Zongbin; Xu, Lida; Wang, Jikong

    2011-08-01

    In computer-aided tolerance design (CAT), integrated design of dimensional and geometric tolerances is still one of the research hotspots. Polychromatic sets theory (PST) is a new mathematic tool, which is especially suitable for formal hierarchical structure models. Based on PST, in this article, a new hierarchical representation model for tolerance synthesis is presented to realise integrated design of dimensional and geometric tolerances. According to the inference relations between unified and individual colours of PST, the synthesis matrices of variational geometric constraints (VGC) are established in the VGC tier of the model, and the synthesis matrices of tolerance types are established in the tolerance type tier of the model. On this basis, the synthesis processes from the feature tier to the VGC tier and from the VGC tier to the tolerance type tier can be realised. VGCs, which are achieved by the synthesis matrices of VGCs, can be combined together to establish a well-constrained VGC network (VGCN). Tolerance types, which are achieved by the synthesis matrices of tolerance types, can be added to the well-constrained VGCN to construct a well-constrained tolerance network. An application example is given in the article to illustrate the synthesis steps.

  4. A method for manufacturing superior set yogurt under reduced oxygen conditions.

    PubMed

    Horiuchi, H; Inoue, N; Liu, E; Fukui, M; Sasaki, Y; Sasaki, T

    2009-09-01

    The yogurt starters Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus are well-known facultatively anaerobic bacteria that can grow in oxygenated environments. We found that they removed dissolved oxygen (DO) in a yogurt mix as the fermentation progressed and that they began to produce acid actively after the DO concentration in the yogurt mix was reduced to 0 mg/kg, suggesting that the DO retarded the production of acid. Yogurt fermentation was carried out at 43 or 37 degrees C both after the DO reduction treatment and without prior treatment. Nitrogen gas was mixed and dispersed into the yogurt mix after inoculation with yogurt starter culture to reduce the DO concentration in the yogurt mix. The treatment that reduced DO concentration in the yogurt mix to approximately 0 mg/kg beforehand caused the starter culture LB81 used in this study to enter into the exponential growth phase earlier. Furthermore, the combination of reduced DO concentration in the yogurt mix beforehand and incubation at a lower temperature (37 degrees C) resulted in a superior set yogurt with a smooth texture and strong curd structure.

  5. A comparative evaluation of PCR- based methods for species- specific determination of African animal trypanosomes in Ugandan cattle

    PubMed Central

    2013-01-01

    Background In recent years, PCR has been become widely applied for the detection of trypanosomes overcoming many of the constraints of parasitological and serological techniques, being highly sensitive and specific for trypanosome detection. Individual species-specific multi-copy trypanosome DNA sequences can be targeted to identify parasites. Highly conserved ribosomal RNA (rRNA) genes are also useful for comparisons between closely related species. The internal transcribed spacer regions (ITS) in particular are relatively small, show variability among related species and are flanked by highly conserved segments to which PCR primers can be designed. Individual variations in inter-species length makes the ITS region a useful marker for identification of multiple trypanosome species within a sample. Methods Six hundred blood samples from cattle collected in Uganda on FTA cards were screened using individual species-specific primers for Trypanosoma congolense, Trypanosoma brucei and Trypanosoma vivax and compared to a modified (using eluate extracted using chelex) ITS-PCR reaction. Results The comparative analysis showed that the species-specific primer sets showed poor agreement with the ITS primer set. Using species-specific PCR for Trypanozoon, a prevalence of 10.5% was observed as compared to 0.2% using ITS PCR (Kappa = 0.03). For Trypanosoma congolense, the species-specific PCR reaction indicated a prevalence of 0% compared to 2.2% using ITS PCR (Kappa = 0). For T. vivax, species-specific PCR detected prevalence of 5.7% compared to 2.8% for ITS PCR (Kappa = 0.29). Conclusions When selecting PCR based tools to apply to epidemiological surveys for generation of prevalence data for animal trypanosomiasis, it is recommended that species-specific primers are used, being the most sensitive diagnostic tool for screening samples to identify members of Trypanozoon (T. b. brucei s.l). While ITS primers are useful for studying the prevalence of trypanosomes

  6. Development and Validation of a Photographic Method to Use for Dietary Assessment in School Settings

    PubMed Central

    Hörnell, Agneta; Hedelin, Marlene; Waling, Maria; Gunnarsdottir, Ingibjörg; Olsson, Cecilia

    2016-01-01

    Objective To develop and validate a photographic method aimed at making assessment of dietary intake in school canteens non-obstrusive, practical and feasible. Methods The study was conducted in two elementary schools representing two different school canteen systems; main dish being served by canteen staff (Iceland), and complete self-serving (Sweden). Food items in serving and leftovers were weighed and photographed. Trained researchers estimated weights of food items by viewing the photographs and comparing them with pictures of half and full reference portions with known weights. Plates of servings and leftovers from 48 children during five school days (n = 448 plates) and a total of 5967 food items were estimated. The researchers’ estimates were then compared with the true weight of the foods and the energy content calculated. Results Weighed and estimated amounts correlated across meals both in grams and as total energy (0.853–0.977, p<0.001). The agreement between estimated energy content in school meals was close to the true measurement from weighed records; on average 4–19 kcal below true values. Organisation of meal service impacted the efficacy of the method as seen in the difference between countries; with Iceland (served by canteen staff) having higher rate of acceptable estimates than Sweden (self-serving), being 95% vs 73% for total amount (g) in serving. Iceland more often had serving size between or above the half and full reference plates compared with Sweden. Conclusions The photographic method provides acceptable estimates of food and energy intake in school canteens. However, greater accuracy can be expected when foods are served by canteen staff compared with self-serving. PMID:27711120

  7. Multiscale optical simulation settings: challenging applications handled with an iterative ray-tracing FDTD interface method.

    PubMed

    Leiner, Claude; Nemitz, Wolfgang; Schweitzer, Susanne; Kuna, Ladislav; Wenzl, Franz P; Hartmann, Paul; Satzinger, Valentin; Sommer, Christian

    2016-03-20

    We show that with an appropriate combination of two optical simulation techniques-classical ray-tracing and the finite difference time domain method-an optical device containing multiple diffractive and refractive optical elements can be accurately simulated in an iterative simulation approach. We compare the simulation results with experimental measurements of the device to discuss the applicability and accuracy of our iterative simulation procedure. PMID:27140556

  8. Multiscale optical simulation settings: challenging applications handled with an iterative ray-tracing FDTD interface method.

    PubMed

    Leiner, Claude; Nemitz, Wolfgang; Schweitzer, Susanne; Kuna, Ladislav; Wenzl, Franz P; Hartmann, Paul; Satzinger, Valentin; Sommer, Christian

    2016-03-20

    We show that with an appropriate combination of two optical simulation techniques-classical ray-tracing and the finite difference time domain method-an optical device containing multiple diffractive and refractive optical elements can be accurately simulated in an iterative simulation approach. We compare the simulation results with experimental measurements of the device to discuss the applicability and accuracy of our iterative simulation procedure.

  9. Physical methods used by Sudanese mothers in rural settings to manage a child with fever.

    PubMed

    Mukhtar, Hanadi M E; Elnimeiri, Mustafa K

    2014-01-01

    Although the mainstays of antipyretic treatments are drugs such as paracetamol and ibuprofen, physical methods are also used. These include tepid sponging, removing clothes, and cooling the environment with fans to improve ventilation. The objective of this study is to assess the physical methods used by Sudanese rural mothers to manage a child with fever. A cross-sectional descriptive study was designed and conducted within 6 months; it involved 332 mothers of children under five. The data were collected through using a standardized administered questionnaire and focus group discussion and analyzed by statistical package for social science version 15.0 (SPSS). Tepid sponging was used by 47% of the interviewed mothers. 15% of the mothers increased fluid intake, 7% bathed the child and 5% put the child in light clothes. 59% of mothers applied tepid sponging on head, 33.9% on all the body, 3.7% and 2.2% on groin area and axilla, respectively. The majority of mothers (86%) used water from refrigerator or zeir [water clay pot] for applying tepid sponging, 9% used tap water, and 3% used ice water. In conclusion, this study revealed that the common physical treatment method for fever used by mothers was tepid sponging with inappropriate application. PMID:27493391

  10. Experiments and other methods for developing expertise with design of experiments in a classroom setting

    NASA Technical Reports Server (NTRS)

    Patterson, John W.

    1990-01-01

    The only way to gain genuine expertise in Statistical Process Control (SPC) and the design of experiments (DOX) is with repeated practice, but not on canned problems with dead data sets. Rather, one must negotiate a wide variety of problems each with its own peculiarities and its own constantly changing data. The problems should not be of the type for which there is a single, well-defined answer that can be looked up in a fraternity file or in some text. The problems should match as closely as possible the open-ended types for which there is always an abundance of uncertainty. These are the only kinds that arise in real research, whether that be basic research in academe or engineering research in industry. To gain this kind of experience, either as a professional consultant or as an industrial employee, takes years. Vast amounts of money, not to mention careers, must be put at risk. The purpose here is to outline some realistic simulation-type lab exercises that are so simple and inexpensive to run that the students can repeat them as often as desired at virtually no cost. Simulations also allow the instructor to design problems whose outcomes are as noisy as desired but still predictable within limits. Also the instructor and the students can learn a great deal more from the postmortum conducted after the exercise is completed. One never knows for sure what the true data should have been when dealing only with real life experiments. To add a bit more realism to the exercises, it is sometimes desirable to make the students pay for each experimental result from a make-believe budget allocation for the problem.

  11. 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

  12. Dynamic-thresholding level set: a novel computer-aided volumetry method for liver tumors in hepatic CT images

    NASA Astrophysics Data System (ADS)

    Cai, Wenli; Yoshida, Hiroyuki; Harris, Gordon J.

    2007-03-01

    Measurement of the volume of focal liver tumors, called liver tumor volumetry, is indispensable for assessing the growth of tumors and for monitoring the response of tumors to oncology treatments. Traditional edge models, such as the maximum gradient and zero-crossing methods, often fail to detect the accurate boundary of a fuzzy object such as a liver tumor. As a result, the computerized volumetry based on these edge models tends to differ from manual segmentation results performed by physicians. In this study, we developed a novel computerized volumetry method for fuzzy objects, called dynamic-thresholding level set (DT level set). An optimal threshold value computed from a histogram tends to shift, relative to the theoretical threshold value obtained from a normal distribution model, toward a smaller region in the histogram. We thus designed a mobile shell structure, called a propagating shell, which is a thick region encompassing the level set front. The optimal threshold calculated from the histogram of the shell drives the level set front toward the boundary of a liver tumor. When the volume ratio between the object and the background in the shell approaches one, the optimal threshold value best fits the theoretical threshold value and the shell stops propagating. Application of the DT level set to 26 hepatic CT cases with 63 biopsy-confirmed hepatocellular carcinomas (HCCs) and metastases showed that the computer measured volumes were highly correlated with those of tumors measured manually by physicians. Our preliminary results showed that DT level set was effective and accurate in estimating the volumes of liver tumors detected in hepatic CT images.

  13. Toddler Feeding: Expectations and Experiences of Low-Income African American Mothers

    ERIC Educational Resources Information Center

    Horodynski, Mildred A.; Brophy-Herb, Holly; Henry, Michelle; Smith, Katharine A.; Weatherspoon, Lorraine

    2009-01-01

    Objective: To ascertain maternal expectations and experiences with mealtimes and feeding of toddlers among low-income African American mothers in two mid- to large-size cities in the United States. Design: Qualitative focus group study. Setting: Two Early Head Start programme sites in a Midwestern state which serve low income families. Method:…

  14. Developing a Cancer Prevention Programme for African-American Daughters and Mothers

    ERIC Educational Resources Information Center

    Annang, Lucy; Spencer, S. Melinda; Jackson, Dawnyéa; Rosemond, Tiara N.; Best, Alicia L.; Williams, Leah R.; Carlos, Bethany

    2015-01-01

    Objective: To describe how nominal group technique was used to inform the development of a breast and cervical cancer awareness programme for African-American adult daughters and mothers. Design: A qualitative approach using nominal group technique. Setting: A mid-sized city in the Southern USA. Method: Nominal group technique was used with 30…

  15. A practical method of predicting client revisit intention in a hospital setting.

    PubMed

    Lee, Kyun Jick

    2005-01-01

    Data mining (DM) models are an alternative to traditional statistical methods for examining whether higher customer satisfaction leads to higher revisit intention. This study used a total of 906 outpatients' satisfaction data collected from a nationwide survey interviews conducted by professional interviewers on a face-to-face basis in South Korea, 1998. Analyses showed that the relationship between overall satisfaction with hospital services and outpatients' revisit intention, along with word-of-mouth recommendation as intermediate variables, developed into a nonlinear relationship. The five strongest predictors of revisit intention were overall satisfaction, intention to recommend to others, awareness of hospital promotion, satisfaction with physician's kindness, and satisfaction with treatment level.

  16. Aiding priority setting in health care: is there a role for the contingent valuation method?

    PubMed

    Olsen, J A

    1997-01-01

    The paper discusses some methodological and measurement aspects with the contingent valuation (CV) method which appear to create problems when eliciting preferences for the relative social valuation of alternative health care programmes. After pointing to biases which tend to exaggerate the true valuations, emphasis is placed on framing issues when applied to health care. Thereafter the paper discusses the extent to which preferences elicited through one's willingness to pay can be used to infer how the respondent would prioritize between the health care programmes in question. New empirical evidence is presented which suggest discrepancies between a CV ranking and the ranking expressed when making a direct ordinal comparison.

  17. Simulation of the electrode shape change in electrochemical machining based on the level set method

    NASA Astrophysics Data System (ADS)

    Topa, V.; Purcar, M.; Avram, A.; Munteanu, C.; Chereches, R.; Grindei, L.

    2012-04-01

    This paper proposes a generally applicable numerical algorithm for the simulation of two dimensional electrode shape changes during electrochemical machining processes. The computational model consists of two coupled problems: an electrode shape change rate analysis and a moving boundary problem. The innovative aspect is that the workpiece shape is computed over a number of predefined time steps by convection of its surface with a velocity proportional and in the direction of the local electrode shape change rate. An example related to the electrochemical machining of a slot in a stainless steel plate is presented here to demonstrate the strong features of the proposed method.

  18. A practical method of predicting client revisit intention in a hospital setting.

    PubMed

    Lee, Kyun Jick

    2005-01-01

    Data mining (DM) models are an alternative to traditional statistical methods for examining whether higher customer satisfaction leads to higher revisit intention. This study used a total of 906 outpatients' satisfaction data collected from a nationwide survey interviews conducted by professional interviewers on a face-to-face basis in South Korea, 1998. Analyses showed that the relationship between overall satisfaction with hospital services and outpatients' revisit intention, along with word-of-mouth recommendation as intermediate variables, developed into a nonlinear relationship. The five strongest predictors of revisit intention were overall satisfaction, intention to recommend to others, awareness of hospital promotion, satisfaction with physician's kindness, and satisfaction with treatment level. PMID:15923917

  19. Long-stroke fast tool servo and a tool setting method for freeform optics fabrication

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Zhou, Xiaoqin; Liu, Zhiwei; Lin, Chao; Ma, Long

    2014-09-01

    Diamond turning assisted by fast tool servo is of high efficiency for the fabrication of freeform optics. This paper describes a long-stroke fast tool servo to obtain a large-amplitude tool motion. It has the advantage of low cost and higher stiffness and natural frequency than other flexure-based long-stroke fast tool servo systems. The fast tool servo is actuated by a voice coil motor and guided by a flexure-hinge structure. Open-loop and close-loop control tests are conducted on the testing platform. While fast tool servo system is an additional motion axis for a diamond turning machine, a tool center adjustment method is described to confirm tool center position in the machine tool coordinate system when the fast tool servo system is fixed on the diamond turning machine. Last, a sinusoidal surface is machined and the results demonstrate that the tool adjustment method is efficient and precise for a flexure-based fast tool servo system, and the fast tool servo system works well on the fabrication of freeform optics.

  20. eLab: bringing together people, data and methods to enhance knowledge discovery in healthcare settings.

    PubMed

    Ainsworth, John; Cunningham, James; Buchan, Iain

    2012-01-01

    The discovery of knowledge from raw data is a multistage process, that typical requires collaboration between experts from disparate disciplines, and the application of a range of methods tailored to the research question. The aim of the eLab is to provide a web-based environment for health professionals and researchers to access health datasets, share knowledge and expertise and to apply methods for analysis and visualization of the results. The eLab is built around the core concept of the Research Object as the mechanism for preserving, reusing and disseminating the knowledge discovery process. The possible range of applications of the eLab is vast, and so the consideration of the trade off between specificity and generality is an important one, that is reflected in the requirements. The architecture and implementation of the eLab is described, and we report on the deployment of eLabs for applications in primary care, long-term conditions management, bariatric surgery and public health.

  1. Accurate Gaussian basis sets for atomic and molecular calculations obtained from the generator coordinate method with polynomial discretization.

    PubMed

    Celeste, Ricardo; Maringolo, Milena P; Comar, Moacyr; Viana, Rommel B; Guimarães, Amanda R; Haiduke, Roberto L A; da Silva, Albérico B F

    2015-10-01

    Accurate Gaussian basis sets for atoms from H to Ba were obtained by means of the generator coordinate Hartree-Fock (GCHF) method based on a polynomial expansion to discretize the Griffin-Wheeler-Hartree-Fock equations (GWHF). The discretization of the GWHF equations in this procedure is based on a mesh of points not equally distributed in contrast with the original GCHF method. The results of atomic Hartree-Fock energies demonstrate the capability of these polynomial expansions in designing compact and accurate basis sets to be used in molecular calculations and the maximum error found when compared to numerical values is only 0.788 mHartree for indium. Some test calculations with the B3LYP exchange-correlation functional for N2, F2, CO, NO, HF, and HCN show that total energies within 1.0 to 2.4 mHartree compared to the cc-pV5Z basis sets are attained with our contracted bases with a much smaller number of polarization functions (2p1d and 2d1f for hydrogen and heavier atoms, respectively). Other molecular calculations performed here are also in very good accordance with experimental and cc-pV5Z results. The most important point to be mentioned here is that our generator coordinate basis sets required only a tiny fraction of the computational time when compared to B3LYP/cc-pV5Z calculations.

  2. A new method to estimate mortality in crisis-affected and resource-poor settings: validation study

    PubMed Central

    Roberts, Bayard; Morgan, Oliver W; Sultani, Mohammed Ghaus; Nyasulu, Peter; Rwebangila, Sunday; Myatt, Mark; Sondorp, Egbert; Chandramohan, Daniel; Checchi, Francesco

    2010-01-01

    Background Data on mortality rates are crucial to guide health interventions in crisis-affected and resource-poor settings. The methods currently available to collect mortality data in such settings feature important methodological limitations. We developed and validated a new method to provide near real-time mortality estimates in such settings. Methods We selected four study sites: Kabul, Afghanistan; Mae La refugee camp, Thailand; Chiradzulu District, Malawi; and Lugufu and Mtabila refugee camps, Tanzania. We recorded information about all deaths in a 60-day period by asking key community informants and decedents’ next of kin to refer interviewers to bereaved households. We used the total number of deaths and population estimates to calculate mortality rates for 60- and 30-day periods. For validation we compared these rates with a best estimate of mortality using capture–recapture analysis with two further independent lists of deaths. Results The population covered by the new method was 76 476 persons in Kabul, 43 794 in Mae La camp, 54 418 in Chiradzulu District and 80 136 in the Tanzania camps. The informant method showed moderate sensitivity (55.0% in Kabul, 64.0% in Mae La, 72.5% in Chiradzulu and 67.7% in Tanzania), but performed better than the active surveillance system in the Tanzania refugee camps. Conclusions The informant method currently features moderate sensitivity for accurately assessing mortality, but warrants further development, particularly considering its advantages over current options (ease of implementation and analysis and near-real estimates of mortality rates). Strategies should be tested to improve the performance of the informant method. PMID:21044978

  3. Leveraging Administrative Data for Program Evaluations: A Method for Linking Data Sets Without Unique Identifiers.

    PubMed

    Lorden, Andrea L; Radcliff, Tiffany A; Jiang, Luohua; Horel, Scott A; Smith, Matthew L; Lorig, Kate; Howell, Benjamin L; Whitelaw, Nancy; Ory, Marcia

    2016-06-01

    In community-based wellness programs, Social Security Numbers (SSNs) are rarely collected to encourage participation and protect participant privacy. One measure of program effectiveness includes changes in health care utilization. For the 65 and over population, health care utilization is captured in Medicare administrative claims data. Therefore, methods as described in this article for linking participant information to administrative data are useful for program evaluations where unique identifiers such as SSN are not available. Following fuzzy matching methodologies, participant information from the National Study of the Chronic Disease Self-Management Program was linked to Medicare administrative data. Linking variables included participant name, date of birth, gender, address, and ZIP code. Seventy-eight percent of participants were linked to their Medicare claims data. Linking program participant information to Medicare administrative data where unique identifiers are not available provides researchers with the ability to leverage claims data to better understand program effects.

  4. Set up an Arc Welding Code with Enthalpy Method in Upwind Scheme

    SciTech Connect

    Ho, J.-E.

    2010-05-21

    In this study, a numerical code with enthalpy method in upwind scheme is proposed to estimate the distribution of thermal stress in the molten pool, which is primarily determined by the type of the input power and travel speed of heating source. To predict the cracker deficit inside the workpiece, a simulated program satisfying the diagonal domination and Scarborough criterion provides a stable iteration. Meantime, an experimental performance, operated by robot arm 'DR-400' to provide a steady and continuous arc welding, was also conducted to verify the simulated result. By surveying the consistence of molten pool bounded by contrast shade and simulated melting contour on the surface of workpiece, the validity of model proposed to predict the thermal cracker has been successfully identified.

  5. Hair care practices in African American women.

    PubMed

    Quinn, Chemene R; Quinn, Timothy M; Kelly, A Paul

    2003-10-01

    Hair care in African American women is wrought with historical and cultural issues. Dermatologists need to improve their understanding of hair and scalp disorders in their African American patient population by being informed about the styling methods commonly used by and for these patients. The styling habits described in this article are intended to encompass the hairstyles adapted by a wide range of African American women with varying hair textures.

  6. System and method for the adaptive mapping of matrix data to sets of polygons

    NASA Technical Reports Server (NTRS)

    Burdon, David (Inventor)

    2003-01-01

    A system and method for converting bitmapped data, for example, weather data or thermal imaging data, to polygons is disclosed. The conversion of the data into polygons creates smaller data files. The invention is adaptive in that it allows for a variable degree of fidelity of the polygons. Matrix data is obtained. A color value is obtained. The color value is a variable used in the creation of the polygons. A list of cells to check is determined based on the color value. The list of cells to check is examined in order to determine a boundary list. The boundary list is then examined to determine vertices. The determination of the vertices is based on a prescribed maximum distance. When drawn, the ordered list of vertices create polygons which depict the cell data. The data files which include the vertices for the polygons are much smaller than the corresponding cell data files. The fidelity of the polygon representation can be adjusted by repeating the logic with varying fidelity values to achieve a given maximum file size or a maximum number of vertices per polygon.

  7. Using the mystery box as a means to explore the scientific method in an undergraduate lecture setting

    NASA Astrophysics Data System (ADS)

    Cook, H. M.; Cook, G. W.

    2015-12-01

    The mystery box is a well-known and well-loved teaching tool designed to encourage students to engage in making observations in order to draw conclusions. We have adapted this exercise, normally used in laboratory settings, for use in a lecture setting in introductory earth science classes. We have tied it to the scientific method such that students are engaging in mystery-box- based inquiry while exploring the steps of the scientific method. It is used in conjunction with a PowerPoint presentation that illustrates and discusses the steps and process integral to the scientific method, which is fundamental to science. Students are encouraged to explore the formal and informal use of the scientific method throughout their educational careers and in their daily lives. Furthermore, students are challenged to analyze the necessity of the scientific method as means for conducting scientific inquiry and exploring the results of such inquiry. A follow-up assignment to the activity asks students to evaluate the efficacy of the activity and associated PowerPoint and discussion. Students consistently report having enjoyed and learned from the process.

  8. Simulation modeling based method for choosing an effective set of fault tolerance mechanisms for real-time avionics systems

    NASA Astrophysics Data System (ADS)

    Bakhmurov, A. G.; Balashov, V. V.; Glonina, A. B.; Pashkov, V. N.; Smeliansky, R. L.; Volkanov, D. Yu.

    2013-12-01

    In this paper, the reliability allocation problem (RAP) for real-time avionics systems (RTAS) is considered. The proposed method for solving this problem consists of two steps: (i) creation of an RTAS simulation model at the necessary level of abstraction and (ii) application of metaheuristic algorithm to find an optimal solution (i. e., to choose an optimal set of fault tolerance techniques). When during the algorithm execution it is necessary to measure the execution time of some software components, the simulation modeling is applied. The procedure of simulation modeling also consists of the following steps: automatic construction of simulation model of the RTAS configuration and running this model in a simulation environment to measure the required time. This method was implemented as an experimental software tool. The tool works in cooperation with DYANA simulation environment. The results of experiments with the implemented method are presented. Finally, future plans for development of the presented method and tool are briefly described.

  9. Using a Mixed Methods Sequential Design to Identify Factors Associated with African American Mothers' Intention to Vaccinate Their Daughters Aged 9 to 12 for HPV with a Purpose of Informing a Culturally-Relevant, Theory-Based Intervention

    ERIC Educational Resources Information Center

    Cunningham, Jennifer L.

    2013-01-01

    The purpose of this sequential, explanatory mixed methods research study was to understand what factors influenced African American maternal intentions to get their daughters aged 9 years to 12 years vaccinated in Alabama. In the first, quantitative phase of the study, the research questions focused on identifying the predictive power of eleven…

  10. Degeneracy relations in QCD and the equivalence of two systematic all-orders methods for setting the renormalization scale

    NASA Astrophysics Data System (ADS)

    Bi, Huan-Yu; Wu, Xing-Gang; Ma, Yang; Ma, Hong-Hao; Brodsky, Stanley J.; Mojaza, Matin

    2015-09-01

    The Principle of Maximum Conformality (PMC) eliminates QCD renormalization scale-setting uncertainties using fundamental renormalization group methods. The resulting scale-fixed pQCD predictions are independent of the choice of renormalization scheme and show rapid convergence. The coefficients of the scale-fixed couplings are identical to the corresponding conformal series with zero β-function. Two all-orders methods for systematically implementing the PMC-scale setting procedure for existing high order calculations are discussed in this article. One implementation is based on the PMC-BLM correspondence (PMC-I); the other, more recent, method (PMC-II) uses the Rδ-scheme, a systematic generalization of the minimal subtraction renormalization scheme. Both approaches satisfy all of the principles of the renormalization group and lead to scale-fixed and scheme-independent predictions at each finite order. In this work, we show that PMC-I and PMC-II scale-setting methods are in practice equivalent to each other. We illustrate this equivalence for the four-loop calculations of the annihilation ratio Re+e- and the Higgs partial width Γ (H → b b bar). Both methods lead to the same resummed ('conformal') series up to all orders. The small scale differences between the two approaches are reduced as additional renormalization group {βi }-terms in the pQCD expansion are taken into account. We also show that special degeneracy relations, which underly the equivalence of the two PMC approaches and the resulting conformal features of the pQCD series, are in fact general properties of non-Abelian gauge theory.

  11. Degeneracy relations in QCD and the equivalence of two systematic all-orders methods for setting the renormalization scale

    SciTech Connect

    Bi, Huan -Yu; Wu, Xing -Gang; Ma, Yang; Ma, Hong -Hao; Brodsky, Stanley J.; Mojaza, Matin

    2015-06-26

    The Principle of Maximum Conformality (PMC) eliminates QCD renormalization scale-setting uncertainties using fundamental renormalization group methods. The resulting scale-fixed pQCD predictions are independent of the choice of renormalization scheme and show rapid convergence. The coefficients of the scale-fixed couplings are identical to the corresponding conformal series with zero β-function. Two all-orders methods for systematically implementing the PMC-scale setting procedure for existing high order calculations are discussed in this article. One implementation is based on the PMC-BLM correspondence (PMC-I); the other, more recent, method (PMC-II) uses the Rδ-scheme, a systematic generalization of the minimal subtraction renormalization scheme. Both approaches satisfy all of the principles of the renormalization group and lead to scale-fixed and scheme-independent predictions at each finite order. In this work, we show that PMC-I and PMC-II scale-setting methods are in practice equivalent to each other. We illustrate this equivalence for the four-loop calculations of the annihilation ratio Re+e and the Higgs partial width I'(H→bb¯). Both methods lead to the same resummed (‘conformal’) series up to all orders. The small scale differences between the two approaches are reduced as additional renormalization group {βi}-terms in the pQCD expansion are taken into account. In addition, we show that special degeneracy relations, which underly the equivalence of the two PMC approaches and the resulting conformal features of the pQCD series, are in fact general properties of non-Abelian gauge theory.

  12. How valid is the tallquist method in screening pregnant women with anemia in poor rural settings of southwestern Nigeria?

    PubMed Central

    Wasiu Olalekan, Adebimpe; Olufemi Emmanuel, Akanni

    2016-01-01

    Background: Diagnosis of anemia is challenging in resource-poor settings due to inadequate laboratory resources. This study assessed the validity of the Tallquist haemoglobinometer in assessing anemia among pregnant women in Osogbo, Southwestern Nigeria. Methods: This was a cross - sectional study, in which 200 pregnant women of reproductive age were selected using multistage sapling method. A checklist was used to collect socio-demographic data and the results of the screening test. Blood collection and analysis were carried out using standardized referenced methods. Results: Mean±SD age of the respondents was 28.9+3.9 yrs.; and 62 (62.6%) had up to primary level education. When Tallquist and Haematocrit methods were compared, there was 68.4%, 83.5% and 100% likelihood of Tallquist method (TM) diagnosing severe, moderate and mild anemia, respectively. The validity indices of the TM versus Haematocrit method as the gold standard revealed the sensitivity of 97.9%, specificity of 92.1%, positive predictive value of 92.4%, and negative predictive value of 97.9% and diagnostic accuracy of 95.0%. When compared to the Haemoglobin Cyanide method, the Tallquist method showed a calculated sensitivity of 96.6%, specificity of 87.4%, positive predictive value of 86.0%, and negative predictive value of 97.0% and diagnostic accuracy of 91.5%. Conclusion: The TM is a valid tool in screening anemia among pregnant women in resource- poor settings and rural primary health care centers in Southwestern Nigeria; therefore, its use should be encouraged, particularly to assess mild to moderate anemia. PMID:27493933

  13. 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…

  14. 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)

  15. 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…

  16. Using an innovative mixed method methodology to investigate the appropriateness of a quantitative instrument in an African context: Antiretroviral treatment and quality of life.

    PubMed

    Greeff, Minrie; Chepuka, Lignet M; Chilemba, Winnie; Chimwaza, Angela F; Kululanga, Lucy I; Kgositau, Mabedi; Manyedi, Eva; Shaibu, Sheila; Wright, Susan C D

    2014-01-01

    The relationship between quality of life (QoL) and antiretroviral treatment (ART) has mainly been studied using quantitative scales often not appropriate for use in other contexts and without taking peoples' lived experiences into consideration. Sub-Saharan Africa has the highest incidence of HIV and AIDS yet there is paucity in research done on QoL. This research report is intended to give an account of the use of a mixed method convergent parallel design as a novice approach to evaluate an instrument's context specificity, appropriateness and usefulness in another context for which it was designed. Data were collected through a qualitative exploration of the experiences of QoL of people living with HIV or AIDS (PLHA) in Africa since being on ART, as well as the quantitative measurements obtained from the HIV/AIDS-targeted quality of life (HAT-QoL) instrument. This study was conducted in three African countries. Permission and ethical approval to conduct the study were obtained. Purposive voluntary sampling was used to recruit PLHA through mediators working in community-based HIV/AIDS organisations and health clinics. Interviews were analysed through open coding and the quantitative data through descriptive statistics and the Cronbach's alpha coefficient. A much wider range and richness of experiences were expressed than measured by the HAT-QoL instrument. Although an effective instrument for use in the USA, it was found not to be sensitive, appropriate and useful in an African context in its present form. The recommendations focus on adapting the instrument using the data from the in-depth interviews or to develop a context-sensitive instrument that could measure QoL of PLHA in Africa.

  17. Comparison between the multiple-set plus 2 weeks of tri-set and traditional multiple-set method on strength and body composition in trained women: a pilot study.

    PubMed

    Garcia, Paula; Nascimento, Dahan da C; Tibana, Ramires A; Barboza, Maria M; Willardson, Jeffrey M; Prestes, Jonato

    2016-01-01

    The manipulation of resistance training (RT) variables affects the neuromuscular adaptations and may also alter body composition. Another important factor to be considered is the presence of high, moderate and low responding subjects to training. The purpose of this study was to compare the effects of multiple-set (MS) and tri-set (TS) RT approaches on muscle strength and body composition following a 12 week programme in trained women (> 1 year of RT experience). A secondary objective was to assess variations in individual responsiveness to the RT by the identification of high (strength gains were > 20%), moderate (10 and 19%) and low responding (< 10%) subjects. Eleven healthy experientially resistance trained women were randomly divided into two groups: MS (n = 6; age 27·17 ± 8·23 years; body mass 57·97 ± 2·48 kg) and TS (n = 5; age 23·20 ± 2·28 years; body mass 61·74 ± 6·95 kg). High responders were found in the training groups (MS n = 4 and TS n = 1), moderate (MS n = 1 and TS n = 3) and low responders (MS n = 1 and TS n = 1). The MS group displayed an increase in squat 1RM (P<0·01), stiff leg deadlift 1RM (P<0·002) and squat repetitions maximum at 50% of 1RM (P<0·04). The TS method significantly increased all strength variables (P<0·05), with no differences between methods (P>0·05). Differences were evident between subjects classified as high, medium and low responding in the stiff leg deadlift 1RM (P = 0·007). Both RT protocols increased strength, with no effect on body composition. The variability in individual responsiveness emphasizes the importance of individualized RT prescription for strength practitioners. PMID:25214387

  18. 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).

  19. Robust, basis-set independent method for the evaluation of charge-transfer energy in noncovalent complexes.

    PubMed

    Řezáč, Jan; de la Lande, Aurélien

    2015-02-10

    Separation of the energetic contribution of charge transfer to interaction energy in noncovalent complexes would provide important insight into the mechanisms of the interaction. However, the calculation of charge-transfer energy is not an easy task. It is not a physically well-defined term, and the results might depend on how it is described in practice. Commonly, the charge transfer is defined in terms of molecular orbitals; in this framework, however, the charge transfer vanishes as the basis set size increases toward the complete basis set limit. This can be avoided by defining the charge transfer in terms of the spatial extent of the electron densities of the interacting molecules, but the schemes used so far do not reflect the actual electronic structure of each particular system and thus are not reliable. We propose a spatial partitioning of the system, which is based on a charge transfer-free reference state, namely superimposition of electron densities of the noninteracting fragments. We show that this method, employing constrained DFT for the calculation of the charge-transfer energy, yields reliable results and is robust with respect to the strength of the charge transfer, the basis set size, and the DFT functional used. Because it is based on DFT, the method is applicable to rather large systems.

  20. Methods to characterize environmental settings of stream and groundwater sampling sites for National Water-Quality Assessment

    USGS Publications Warehouse

    Nakagaki, Naomi; Hitt, Kerie J.; Price, Curtis V.; Falcone, James A.

    2012-01-01

    Characterization of natural and anthropogenic features that define the environmental settings of sampling sites for streams and groundwater, including drainage basins and groundwater study areas, is an essential component of water-quality and ecological investigations being conducted as part of the U.S. Geological Survey's National Water-Quality Assessment program. Quantitative characterization of environmental settings, combined with physical, chemical, and biological data collected at sampling sites, contributes to understanding the status of, and influences on, water-quality and ecological conditions. To support studies for the National Water-Quality Assessment program, a geographic information system (GIS) was used to develop a standard set of methods to consistently characterize the sites, drainage basins, and groundwater study areas across the nation. This report describes three methods used for characterization-simple overlay, area-weighted areal interpolation, and land-cover-weighted areal interpolation-and their appropriate applications to geographic analyses that have different objectives and data constraints. In addition, this document records the GIS thematic datasets that are used for the Program's national design and data analyses.

  1. A kernel machine method for detecting effects of interaction between multidimensional variable sets: an imaging genetics application.

    PubMed

    Ge, Tian; Nichols, Thomas E; Ghosh, Debashis; Mormino, Elizabeth C; Smoller, Jordan W; Sabuncu, Mert R

    2015-04-01

    Measurements derived from neuroimaging data can serve as markers of disease and/or healthy development, are largely heritable, and have been increasingly utilized as (intermediate) phenotypes in genetic association studies. To date, imaging genetic studies have mostly focused on discovering isolated genetic effects, typically ignoring potential interactions with non-genetic variables such as disease risk factors, environmental exposures, and epigenetic markers. However, identifying significant interaction effects is critical for revealing the true relationship between genetic and phenotypic variables, and shedding light on disease mechanisms. In this paper, we present a general kernel machine based method for detecting effects of the interaction between multidimensional variable sets. This method can model the joint and epistatic effect of a collection of single nucleotide polymorphisms (SNPs), accommodate multiple factors that potentially moderate genetic influences, and test for nonlinear interactions between sets of variables in a flexible framework. As a demonstration of application, we applied the method to the data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) to detect the effects of the interactions between candidate Alzheimer's disease (AD) risk genes and a collection of cardiovascular disease (CVD) risk factors, on hippocampal volume measurements derived from structural brain magnetic resonance imaging (MRI) scans. Our method identified that two genes, CR1 and EPHA1, demonstrate significant interactions with CVD risk factors on hippocampal volume, suggesting that CR1 and EPHA1 may play a role in influencing AD-related neurodegeneration in the presence of CVD risks. PMID:25600633

  2. Provider Use of Collaborative Goal Setting with Glaucoma Patients

    PubMed Central

    Sleath, Betsy; Slota, Catherine; Blalock, Susan J.; Sayner, Robyn; Carpenter, Delesha M.; Muir, Kelly W.; Hartnett, Mary Elizabeth; Robin, Alan L.

    2014-01-01

    Purpose The purpose of this preliminary study was to describe the extent to which providers used collaborative goal setting and individualized assessment with patients who were newly prescribed glaucoma medications. Methods English-speaking glaucoma suspect patients from six ophthalmology clinics who were newly prescribed glaucoma medications had their medical visits video-tape recorded and were interviewed after the visits. The video-tapes were transcribed and coded to examine provider use of collaborative goal setting and individualized assessment. Results Fifty-one patients seeing 12 ophthalmologists participated. Providers gave patients glaucoma treatment options during 37% of the visits; only five providers gave patients treatment options Providers asked for patient treatment preferences in less than 20% of the visits; only two providers asked for patient treatment preferences. Providers were significantly more likely to ask African American patients for their preferences or ideas concerning treatment than non-African American patients (Pearson chi-square= 4.1, p=0.04). Providers were also significantly more likely to ask African American patients about their confidence in using glaucoma medication regularly than non-African American patients (Pearson chi-square=8.2, p=0.004). Providers asked about patient views about glaucoma in less than 20% of the visits; five providers asked patients their views on glaucoma and its treatment. Providers were significantly more likely to ask African American patients about their views of glaucoma than non-African American patients (Pearson chi-square=5.62, p=0.02). Conclusions Eye care providers often did not use collaborative goal setting or conduct individualized assessments of patient views of glaucoma when prescribing treatment for the first time. PMID:24705480

  3. A degenerate primer MOB typing (DPMT) method to classify gamma-proteobacterial plasmids in clinical and environmental settings.

    PubMed

    Alvarado, Andrés; Garcillán-Barcia, M Pilar; de la Cruz, Fernando

    2012-01-01

    Transmissible plasmids are responsible for the spread of genetic determinants, such as antibiotic resistance or virulence traits, causing a large ecological and epidemiological impact. Transmissible plasmids, either conjugative or mobilizable, have in common the presence of a relaxase gene. Relaxases were previously classified in six protein families according to their phylogeny. Degenerate primers hybridizing to coding sequences of conserved amino acid motifs were designed to amplify related relaxase genes from γ-Proteobacterial plasmids. Specificity and sensitivity of a selected set of 19 primer pairs were first tested using a collection of 33 reference relaxases, representing the diversity of γ-Proteobacterial plasmids. The validated set was then applied to the analysis of two plasmid collections obtained from clinical isolates. The relaxase screening method, which we call "Degenerate Primer MOB Typing" or DPMT, detected not only most known Inc/Rep groups, but also a plethora of plasmids not previously assigned to any Inc group or Rep-type.

  4. A discriminant function model as an alternative method to spirometry for COPD screening in primary care settings in China

    PubMed Central

    Cui, Jiangyu; Zhou, Yumin; Tian, Jia; Wang, Xinwang; Zheng, Jingping; Zhong, Nanshan

    2012-01-01

    Objective COPD is often underdiagnosed in a primary care setting where the spirometry is unavailable. This study was aimed to develop a simple, economical and applicable model for COPD screening in those settings. Methods First we established a discriminant function model based on Bayes’ Rule by stepwise discriminant analysis, using the data from 243 COPD patients and 112 non-COPD subjects from our COPD survey in urban and rural communities and local primary care settings in Guangdong Province, China. We then used this model to discriminate COPD in additional 150 subjects (50 non-COPD and 100 COPD ones) who had been recruited by the same methods as used to have established the model. All participants completed pre- and post-bronchodilator spirometry and questionnaires. COPD was diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease criteria. The sensitivity and specificity of the discriminant function model was assessed. Results The established discriminant function model included nine variables: age, gender, smoking index, body mass index, occupational exposure, living environment, wheezing, cough and dyspnoea. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, accuracy and error rate of the function model to discriminate COPD were 89.00%, 82.00%, 4.94, 0.13, 86.66% and 13.34%, respectively. The accuracy and Kappa value of the function model to predict COPD stages were 70% and 0.61 (95% CI, 0.50 to 0.71). Conclusions This discriminant function model may be used for COPD screening in primary care settings in China as an alternative option instead of spirometry. PMID:23205284

  5. Approximate method for predicting the permanent set in a beam in vacuo and in water subject to a shock wave

    NASA Technical Reports Server (NTRS)

    Stiehl, A. L.; Haberman, R. C.; Cowles, J. H.

    1988-01-01

    An approximate method to compute the maximum deformation and permanent set of a beam subjected to shock wave laoding in vacuo and in water was investigated. The method equates the maximum kinetic energy of the beam (and water) to the elastic plastic work done by a static uniform load applied to a beam. Results for the water case indicate that the plastic deformation is controlled by the kinetic energy of the water. The simplified approach can result in significant savings in computer time or it can expediently be used as a check of results from a more rigorous approach. The accuracy of the method is demonstrated by various examples of beams with simple support and clamped support boundary conditions.

  6. 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

  7. On the computation of viscous terms for incompressible two-phase flows with Level Set/Ghost Fluid Method

    NASA Astrophysics Data System (ADS)

    Lalanne, Benjamin; Villegas, Lucia Rueda; Tanguy, Sébastien; Risso, Frédéric

    2015-11-01

    In this paper, we present a detailed analysis of the computation of the viscous terms for the simulation of incompressible two-phase flows in the framework of Level Set/Ghost Fluid Method when viscosity is discontinuous across the interface. Two pioneering papers on the topic, Kang et al. [10] and Sussman et al. [26], proposed two different approaches to deal with viscous terms. However, a definitive assessment of their respective efficiency is currently not available. In this paper, we demonstrate from theoretical arguments and confirm from numerical simulations that these two approaches are equivalent from a continuous point of view and we compare their accuracies in relevant test-cases. We also propose a new intermediate method which uses the properties of the two previous methods. This new method enables a simple implementation for an implicit temporal discretization of the viscous terms. In addition, the efficiency of the Delta Function method [24] is also assessed and compared to the three previous ones, which allow us to propose a general overview of the accuracy of all available methods. The selected test-cases involve configurations wherein viscosity plays a major role and for which either theoretical results or experimental data are available as reference solutions: simulations of spherical rising bubbles, shape-oscillating bubbles and deformed rising bubbles at low Reynolds numbers.

  8. 3-dimensional throat region segmentation from MRI data based on Fourier interpolation and 3-dimensional level set methods.

    PubMed

    Campbell, Sean; Doshi, Trushali; Soraghan, John; Petropoulakis, Lykourgos; Di Caterina, Gaetano; Grose, Derek; MacKenzie, Kenneth

    2015-01-01

    A new algorithm for 3D throat region segmentation from magnetic resonance imaging (MRI) is presented. The proposed algorithm initially pre-processes the MRI data to increase the contrast between the throat region and its surrounding tissues and to reduce artifacts. Isotropic 3D volume is reconstructed using the Fourier interpolation. Furthermore, a cube encompassing the throat region is evolved using level set method to form a smooth 3D boundary of the throat region. The results of the proposed algorithm on real and synthetic MRI data are used to validate the robustness and accuracy of the algorithm.

  9. A level set method for image segmentation in the presence of intensity inhomogeneities with application to MRI.

    PubMed

    Li, Chunming; Huang, Rui; Ding, Zhaohua; Gatenby, J Chris; Metaxas, Dimitris N; Gore, John C

    2011-07-01

    Intensity inhomogeneity often occurs in real-world images, which presents a considerable challenge in image segmentation. The most widely used image segmentation algorithms are region-based and typically rely on the homogeneity of the image intensities in the regions of interest, which often fail to provide accurate segmentation results due to the intensity inhomogeneity. This paper proposes a novel region-based method for image segmentation, which is able to deal with intensity inhomogeneities in the segmentation. First, based on the model of images with intensity inhomogeneities, we derive a local intensity clustering property of the image intensities, and define a local clustering criterion function for the image intensities in a neighborhood of each point. This local clustering criterion function is then integrated with respect to the neighborhood center to give a global criterion of image segmentation. In a level set formulation, this criterion defines an energy in terms of the level set functions that represent a partition of the image domain and a bias field that accounts for the intensity inhomogeneity of the image. Therefore, by minimizing this energy, our method is able to simultaneously segment the image and estimate the bias field, and the estimated bias field can be used for intensity inhomogeneity correction (or bias correction). Our method has been validated on synthetic images and real images of various modalities, with desirable performance in the presence of intensity inhomogeneities. Experiments show that our method is more robust to initialization, faster and more accurate than the well-known piecewise smooth model. As an application, our method has been used for segmentation and bias correction of magnetic resonance (MR) images with promising results. PMID:21518662

  10. A three-dimensional coupled Nitsche and level set method for electrohydrodynamic potential flows in moving domains

    NASA Astrophysics Data System (ADS)

    Johansson, A.; Garzon, M.; Sethian, J. A.

    2016-03-01

    In this paper we present a new algorithm for computing three-dimensional electrohydrodynamic flow in moving domains which can undergo topological changes. We consider a non-viscous, irrotational, perfect conducting fluid and introduce a way to model the electrically charged flow with an embedded potential approach. To numerically solve the resulting system, we combine a level set method to track both the free boundary and the surface velocity potential with a Nitsche finite element method for solving the Laplace equations. This results in an algorithmic framework that does not require body-conforming meshes, works in three dimensions, and seamlessly tracks topological change. Assembling this coupled system requires care: while convergence and stability properties of Nitsche's methods have been well studied for static problems, they have rarely been considered for moving domains or for obtaining the gradients of the solution on the embedded boundary. We therefore investigate the performance of the symmetric and non-symmetric Nitsche formulations, as well as two different stabilization techniques. The global algorithm and in particular the coupling between the Nitsche solver and the level set method are also analyzed in detail. Finally we present numerical results for several time-dependent problems, each one designed to achieve a specific objective: (a) The oscillation of a perturbed sphere, which is used for convergence studies and the examination of the Nitsche methods; (b) The break-up of a two lobe droplet with axial symmetry, which tests the capability of the algorithm to go past flow singularities such as topological changes and preservation of an axi-symmetric flow, and compares results to previous axi-symmetric calculations; (c) The electrohydrodynamical deformation of a thin film and subsequent jet ejection, which will account for the presence of electrical forces in a non-axi-symmetric geometry.

  11. Implicit Stereotyping and Medical Decisions: Unconscious Stereotype Activation in Practitioners' Thoughts About African Americans

    PubMed Central

    Stone, Jeff; Childs, Amanda

    2012-01-01

    Objectives. We investigated whether stereotypes unconsciously influence the thinking and behavior of physicians, as they have been shown to do in other professional settings, such as among law enforcement personnel and teachers. Methods. We conducted 2 studies to examine whether stereotypes are implicitly activated in physicians. Study 1 assessed what diseases and treatments doctors associate with African Americans. Study 2 presented these (and control terms) to doctors as part of a computerized task. Subliminal images of African American and White men appeared prior to each word, and reaction times to words were recorded. Results. When primed with an African American face, doctors reacted more quickly for stereotypical diseases, indicating an implicit association of certain diseases with African Americans. These comprised not only diseases African Americans are genetically predisposed to, but also conditions and social behaviors with no biological association (e.g., obesity, drug abuse). Conclusions. We found implicit stereotyping among physicians; faces they never consciously saw altered performance. This suggests that diagnoses and treatment of African American patients may be biased, even in the absence of the practitioner's intent or awareness. PMID:22420815

  12. Oral Cancer in African Americans: Addressing Health Disparities

    ERIC Educational Resources Information Center

    Dodd, Virginia J.; Watson, Jennifer M.; Choi, Youjin; Tomar, Scott L.; Logan, Henrietta L.

    2008-01-01

    Objectives: To explore factors underlying African Americans' perceptions of oral cancer and the oral cancer exam. Study findings were used to guide development of oral cancer messages designed to increase oral cancer exams among African Americans. Methods: Focus groups were conducted to understand African Americans' attitudes and expectations…

  13. Evaluation of two sets of immunohistochemical and Western blot confirmatory methods in the detection of typical and atypical BSE cases

    PubMed Central

    2011-01-01

    Background Three distinct forms of bovine spongiform encephalopathy (BSE), defined as classical (C-), low (L-) or high (H-) type, have been detected through ongoing active and passive surveillance systems for the disease. The aim of the present study was to compare the ability of two sets of immunohistochemical (IHC) and Western blot (WB) BSE confirmatory protocols to detect C- and atypical (L- and H-type) BSE forms. Obex samples from cases of United States and Italian C-type BSE, a U.S. H-type and an Italian L-type BSE case were tested in parallel using the two IHC sets and WB methods. Results The two IHC techniques proved equivalent in identifying and differentiating between C-type, L-type and H-type BSE. The IHC protocols appeared consistent in the identification of PrPSc distribution and deposition patterns in relation to the BSE type examined. Both IHC methods evidenced three distinct PrPSc phenotypes for each type of BSE: prevailing granular and linear tracts pattern in the C-type; intraglial and intraneuronal deposits in the H-type; plaques in the L-type. Also, the two techniques gave comparable results for PrPSc staining intensity on the C- and L-type BSE samples, whereas a higher amount of intraglial and intraneuronal PrPSc deposition on the H-type BSE case was revealed by the method based on a stronger demasking step. Both WB methods were consistent in identifying classical and atypical BSE forms and in differentiating the specific PrPSc molecular weight and glycoform ratios of each form. Conclusions The study showed that the IHC and WB BSE confirmatory methods were equally able to recognize C-, L- and H-type BSE forms and to discriminate between their different immunohistochemical and molecular phenotypes. Of note is that for the first time one of the two sets of BSE confirmatory protocols proved effective in identifying the L-type BSE form. This finding helps to validate the suitability of the BSE confirmatory tests for BSE surveillance currently in

  14. AN ACCURATE NEW METHOD OF CALCULATING ABSOLUTE MAGNITUDES AND K-CORRECTIONS APPLIED TO THE SLOAN FILTER SET

    SciTech Connect

    Beare, Richard; Brown, Michael J. I.; Pimbblet, Kevin

    2014-12-20

    We describe an accurate new method for determining absolute magnitudes, and hence also K-corrections, that is simpler than most previous methods, being based on a quadratic function of just one suitably chosen observed color. The method relies on the extensive and accurate new set of 129 empirical galaxy template spectral energy distributions from Brown et al. A key advantage of our method is that we can reliably estimate random errors in computed absolute magnitudes due to galaxy diversity, photometric error and redshift error. We derive K-corrections for the five Sloan Digital Sky Survey filters and provide parameter tables for use by the astronomical community. Using the New York Value-Added Galaxy Catalog, we compare our K-corrections with those from kcorrect. Our K-corrections produce absolute magnitudes that are generally in good agreement with kcorrect. Absolute griz magnitudes differ by less than 0.02 mag and those in the u band by ∼0.04 mag. The evolution of rest-frame colors as a function of redshift is better behaved using our method, with relatively few galaxies being assigned anomalously red colors and a tight red sequence being observed across the whole 0.0 < z < 0.5 redshift range.

  15. Optimization of intensity modulated beams with volume constraints using two methods: cost function minimization and projections onto convex sets.

    PubMed

    Cho, P S; Lee, S; Marks, R J; Oh, S; Sutlief, S G; Phillips, M H

    1998-04-01

    For accurate prediction of normal tissue tolerance, it is important that the volumetric information of dose distribution be considered. However, in dosimetric optimization of intensity modulated beams, the dose-volume factor is usually neglected. In this paper we describe two methods of volume-dependent optimization for intensity modulated beams such as those generated by computer-controlled multileaf collimators. The first method uses a volume sensitive penalty function in which fast simulated annealing is used for cost function minimization (CFM). The second technique is based on the theory of projections onto convex sets (POCS) in which the dose-volume constraint is replaced by a limit on integral dose. The ability of the methods to respect the dose-volume relationship was demonstrated by using a prostate example involving partial volume constraints to the bladder and the rectum. The volume sensitive penalty function used in the CFM method can be easily adopted by existing optimization programs. The convex projection method can find solutions in much shorter time with minimal user interaction.

  16. Introduction of a fully relativistic capable basis set in the ab initio orthogonalized linear combination of atomic orbitals method

    NASA Astrophysics Data System (ADS)

    Thomas, Patrick Ryan

    Large simulation cell sizes, relativistic effects, and the need to correctly model excited state properties are major impediments to the accurate prediction of the optical properties of candidate materials for solid-state laser crystal and luminescent applications. To overcome these challenges, new methods must be created to improve the electron orbital wavefunction and interactions. In this work, a method has been developed to create new analytical four-component, fully-relativistic and single-component scalar relativistic descriptions of the atomic orbital wave functions from Grasp2K numerically represented atomic orbitals. In addition, adapted theory for the calculation of the relativistic kinetic energy contribution to Hamiltonian which bypasses directly solving the Dirac equation has been explicated. The orbital description improvements are tested against YAG, YBCO, SnO2 and BiF3. The improvements to the basis set reflect an improvement in both computational speed and accuracy.

  17. LV wall segmentation using the variational level set method (LSM) with additional shape constraint for oedema quantification

    NASA Astrophysics Data System (ADS)

    Kadir, K.; Gao, H.; Payne, A.; Soraghan, J.; Berry, C.

    2012-10-01

    In this paper an automatic algorithm for the left ventricle (LV) wall segmentation and oedema quantification from T2-weighted cardiac magnetic resonance (CMR) images is presented. The extent of myocardial oedema delineates the ischaemic area-at-risk (AAR) after myocardial infarction (MI). Since AAR can be used to estimate the amount of salvageable myocardial post-MI, oedema imaging has potential clinical utility in the management of acute MI patients. This paper presents a new scheme based on the variational level set method (LSM) with additional shape constraint for the segmentation of T2-weighted CMR image. In our approach, shape information of the myocardial wall is utilized to introduce a shape feature of the myocardial wall into the variational level set formulation. The performance of the method is tested using real CMR images (12 patients) and the results of the automatic system are compared to manual segmentation. The mean perpendicular distances between the automatic and manual LV wall boundaries are in the range of 1-2 mm. Bland-Altman analysis on LV wall area indicates there is no consistent bias as a function of LV wall area, with a mean bias of -121 mm2 between individual investigator one (IV1) and LSM, and -122 mm2 between individual investigator two (IV2) and LSM when compared to two investigators. Furthermore, the oedema quantification demonstrates good correlation when compared to an expert with an average error of 9.3% for 69 slices of short axis CMR image from 12 patients.

  18. Mask pattern recovery by level set method based inverse inspection technology (IIT) and its application on defect auto disposition

    NASA Astrophysics Data System (ADS)

    Park, Jin-Hyung; Chung, Paul D. H.; Jeon, Chan-Uk; Cho, Han Ku; Pang, Linyong; Peng, Danping; Tolani, Vikram; Cecil, Tom; Kim, David; Baik, KiHo

    2009-10-01

    At the most advanced technology nodes, such as 32nm and 22nm, aggressive OPC and Sub-Resolution Assist Features (SRAFs) are required. However, their use results in significantly increased mask complexity, making mask defect disposition more challenging than ever. This paper describes how mask patterns can first be recovered from the inspection images by applying patented algorithms using Level Set Methods. The mask pattern recovery step is then followed by aerial/wafer image simulation, the results of which can be plugged into an automated mask defect disposition system based on aerial/wafer image. The disposition criteria are primarily based on wafer-plane CD variance. The system also connects to a post-OPC lithography verification tool that can provide gauges and CD specs, thereby enabling them to be used in mask defect disposition as well. Results on both programmed defects and production defects collected at Samsung mask shop are presented to show the accuracy and consistency of using the Level Set Methods and aerial/wafer image based automated mask disposition.

  19. Validation of Five Minimally Obstructive Methods to Estimate Physical Activity Energy Expenditure in Young Adults in Semi-Standardized Settings

    PubMed Central

    Schneller, Mikkel B.; Pedersen, Mogens T.; Gupta, Nidhi; Aadahl, Mette; Holtermann, Andreas

    2015-01-01

    We compared the accuracy of five objective methods, including two newly developed methods combining accelerometry and activity type recognition (Acti4), against indirect calorimetry, to estimate total energy expenditure (EE) of different activities in semi-standardized settings. Fourteen participants performed a standardized and semi-standardized protocol including seven daily life activity types, while having their EE measured by indirect calorimetry. Simultaneously, physical activity was quantified by an ActivPAL3, two ActiGraph GT3X+’s and an Actiheart. EE was estimated by the standard ActivPAL3 software (ActivPAL), ActiGraph GT3X+ (ActiGraph) and Actiheart (Actiheart), and by a combination of activity type recognition via Acti4 software and activity counts per minute (CPM) of either a hip- or thigh-worn ActiGraph GT3X+ (AGhip + Acti4 and AGthigh + Acti4). At group level, estimated physical activities EE by Actiheart (MSE = 2.05) and AGthigh + Acti4 (MSE = 0.25) were not significantly different from measured EE by indirect calorimetry, while significantly underestimated by ActiGraph, ActivPAL and AGhip + Acti4. AGthigh + Acti4 and Actiheart explained 77% and 45%, of the individual variations in measured physical activity EE by indirect calorimetry, respectively. This study concludes that combining accelerometer data from a thigh-worn ActiGraph GT3X+ with activity type recognition improved the accuracy of activity specific EE estimation against indirect calorimetry in semi-standardized settings compared to previously validated methods using CPM only. PMID:25781506

  20. Rationale, Design and Methods of the Ecological Study of Sexual Behaviors and HIV/STI among African American Men Who Have Sex with Men in the Southeastern United States (The MARI Study)

    PubMed Central

    Hickson, DeMarc A.; Truong, Nhan L.; Smith-Bankhead, Neena; Sturdevant, Nikendrick; Duncan, Dustin T.; Schnorr, Jordan; Gipson, June A.; Mena, Leandro A.

    2015-01-01

    Background This paper describes the rationale, design, and methodology of the Ecological Study of Sexual Behaviors and HIV/STI among African American Men Who Have Sex with Men (MSM) in the Southeastern United States (U.S.; known locally simply as the MARI Study). Methods Participants are African American MSM aged 18 years and older residing in the deep South. Results Between 2013 and 2015, 800 African American MSM recruited from two study sites (Jackson, MS and Atlanta, GA) will undergo a 1.5-hour examination to obtain anthropometric and blood pressure measures as well as to undergo testing for sexually transmitted infections (STI), including HIV. Intrapersonal, interpersonal, and environmental factors are assessed by audio computer-assisted self-interview survey. Primary outcomes include sexual risk behaviors (e.g., condomless anal sex) and prevalent STIs (HIV, syphilis, gonorrhea, and Chlamydia). Conclusion The MARI Study will typify the HIV environmental 'riskscape' and provide empirical evidence into novel ecological correlates of HIV risk among African American MSM in the deep South, a population most heavily impacted by HIV. The study's anticipated findings will be of interest to a broad audience and lead to more informed prevention efforts, including effective policies and interventions, that achieve the goals of the updated 2020 U.S. National HIV/AIDS Strategy. PMID:26700018

  1. Dry deposition of nitrogen compounds (NO2, HNO3, NH3), sulfur dioxide and ozone in West and Central African ecosystems using the inferential method

    NASA Astrophysics Data System (ADS)

    Adon, M.; Galy-Lacaux, C.; Yoboue, V.; Delon, C.; Solmon, F.; Kaptue Tchuente, A. T.

    2013-05-01

    This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long term monitoring of gas concentrations (1998-2007) established on seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2, and O3) and on the other hand simulated dry deposition velocities (Vd). Vd were calculated using the big-leaf model of Zhang et al. (2003b). In the model of deposition, surface and meteorological conditions specific to IDAF sites have been adapted in order to simulate Vd representative of major African ecosystems. The monthly, seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3, and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from 0.4 ± 0.0 to 0.8 ± 0.2 kg N ha-1 yr-1 for NO2, from 0.7 ± 0.1 to 1.0 ± 0.3 kg N ha-1 yr-1 for HNO3, and from 2.3 ± 0.8 to 10.5 ± 5.0 kg N ha-1 yr-1 for NH3 over the study period (1998-2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (11.2-11.8 kg N ha-1 yr-1) than in wet and dry savannas (3.4-5.3 kg N ha-1 yr-1). NH3 dominated nitrogen dry deposition, representing 67-80% of the total. The annual mean dry deposition fluxes of ozone range between 11.3 ± 4.7 and 17.5 ± 3.0 kg ha-1 yr-1 in dry savannas, 17.5 ± 3.0 and 19.2 ± 2.9 kg ha-1 yr-1 in wet savannas, and 10.6 ± 2.0 and 13.2 ± 3.6 kg ha-1 yr-1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower of a factor of 2-3, compared to others ecosystems. Along the ecosystem transect, annual mean of SO2 dry deposition fluxes present low values and a small variability (0.5 to 1 kg S ha-1 yr-1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period.

  2. “I Just Can’t Do It Anymore” Patterns of Physical Activity and Cardiac Rehabilitation in African Americans with Heart Failure: A Mixed Method Study

    PubMed Central

    McCarthy, Margaret; Katz, Stuart D.; Schipper, Judith; Dickson, Victoria Vaughan

    2015-01-01

    Physical activity and cardiac rehabilitation (CR) are components of heart failure (HF) self-care. The aims of this study were to describe patterns of physical activity in African Americans (n = 30) with HF and to explore experience in CR. This was a mixed method, concurrent nested, predominantly qualitative study. Qualitative data were collected via interviews exploring typical physical activity, and CR experience. It was augmented by quantitative data measuring HF severity, self-care, functional capacity and depressive symptoms. Mean age was 60 ± 15 years; 65% were New York Heart Association (NYHA) class III HF. Forty-three percent reported that they did less than 30 min of exercise in the past week; 23% were told “nothing” about exercise by their provider, and 53% were told to do “minimal exercise”. A measure of functional capacity indicated the ability to do moderate activity. Two related themes stemmed from the narratives describing current physical activity: “given up” and “still trying”. Six participants recalled referral to CR with one person participating. There was high concordance between qualitative and quantitative data, and evidence that depression may play a role in low levels of physical activity. Findings highlight the need for strategies to increase adherence to current physical activity guidelines in this older minority population with HF. PMID:27417807

  3. Intensity of play behavior as a potential measure of welfare: A novel method for quantifying the integrated intensity of behavior in African elephants.

    PubMed

    Vicino, Greg A; Marcacci, Emily S

    2015-01-01

    To the authors' knowledge there is currently no discrete index to measure the integrated intensity of a play bout in mammals, despite the potential for using intensity and duration of play bouts as a measure of physical activity and welfare. This study was developed to test an equation that quantified the intensity and duration of play bouts in a particularly gregarious mammal, African elephants (Loxodonta africana) housed at the San Diego Zoo Safari Park in Escondido, CA. To quantify these behaviors, we created a scale of intensity and a subsequent equation that produces an index value, giving each unique bout a score. A compilation of these scores provides a range of intensity of play behavior that is a representative value for that particular herd at that point in time, and thus a database to which later bouts can be compared. It can be argued that play behavior is an indicator of positive welfare, and if quantifiable, it is our belief that it can be used as an additional measure of positive welfare in zoo housed animals. Here we present the methods and technique used to calculate a standardized Integrated Play Index (IPI) that has potential for use in other socially living species that are known to exhibit play behavior. PMID:26251201

  4. Intensity of play behavior as a potential measure of welfare: A novel method for quantifying the integrated intensity of behavior in African elephants.

    PubMed

    Vicino, Greg A; Marcacci, Emily S

    2015-01-01

    To the authors' knowledge there is currently no discrete index to measure the integrated intensity of a play bout in mammals, despite the potential for using intensity and duration of play bouts as a measure of physical activity and welfare. This study was developed to test an equation that quantified the intensity and duration of play bouts in a particularly gregarious mammal, African elephants (Loxodonta africana) housed at the San Diego Zoo Safari Park in Escondido, CA. To quantify these behaviors, we created a scale of intensity and a subsequent equation that produces an index value, giving each unique bout a score. A compilation of these scores provides a range of intensity of play behavior that is a representative value for that particular herd at that point in time, and thus a database to which later bouts can be compared. It can be argued that play behavior is an indicator of positive welfare, and if quantifiable, it is our belief that it can be used as an additional measure of positive welfare in zoo housed animals. Here we present the methods and technique used to calculate a standardized Integrated Play Index (IPI) that has potential for use in other socially living species that are known to exhibit play behavior.

  5. The Objective Borderline Method (OBM): A Probability-Based Model for Setting up an Objective Pass/Fail Cut-Off Score in Medical Programme Assessments

    ERIC Educational Resources Information Center

    Shulruf, Boaz; Turner, Rolf; Poole, Phillippa; Wilkinson, Tim

    2013-01-01

    The decision to pass or fail a medical student is a "high stakes" one. The aim of this study is to introduce and demonstrate the feasibility and practicality of a new objective standard-setting method for determining the pass/fail cut-off score from borderline grades. Three methods for setting up pass/fail cut-off scores were compared: the…

  6. The Dangers of Unsystematic Selection Methods and the Representativeness of 46 Samples of African Test-Takers

    ERIC Educational Resources Information Center

    Wicherts, Jelte M.; Dolan, Conor V.; van der Maas, Han L. J.

    2010-01-01

    In this rejoinder, we criticize Lynn and Meisenberg's (this issue) methods to estimate the average IQ (in terms of British norms after correction of the Flynn Effect) of the Black population of sub-Saharan Africa. We argue that their review of the literature is unsystematic, as it involves the inconsistent use of rules to determine the…

  7. VIALS: An Eulerian tool based on total variation and the level set method for studying dynamical systems

    NASA Astrophysics Data System (ADS)

    You, Guoqiao; Leung, Shingyu

    2014-06-01

    We propose a new Eulerian tool to study complicated dynamical systems based on the average growth in the surface area of a family of level surfaces represented implicitly by a level set function. Since this proposed quantity determines the temporal variation of the averaged surface area of all level surfaces, we name the quantity the Variation of the Integral over Area of Level Surfaces (VIALS). Numerically, all these infinitely many level surfaces are advected according to the given dynamics by solving one single linear advection equation. To develop a computationally efficient approach, we apply the coarea formula and rewrite the surface area integral as a simple integral relating the total variation (TV) of the level set function. The proposed method can be easily incorporated with a recent Eulerian algorithm for efficient computation of flow maps to speed up our approach. We will also prove that the proposed VIALS is closely related to the computation of the finite time Lyapunov exponent (FTLE) in the Lagrangian coherent structure (LCS) extraction. This connects our proposed Eulerian approach to widely used Lagrangian techniques for understanding complicated dynamical systems.

  8. Optimization of Physical Working Environment Setting to Improve Productivity and Minimize Error by Taguchi and VIKOR Methods

    NASA Astrophysics Data System (ADS)

    Ilma Rahmillah, Fety

    2016-01-01

    The working environment is one factor that has contribution to the worker's performance, especially for continuous and monotonous works. L9 Taguchi design experiment for inner array is used to design the experiment which was carried out in laboratory whereas L4 is for outer array. Four control variables with three levels of each are used to get the optimal combination of working environment setting. Four responses are also measured to know the effect of four control factors. Results shown that by using ANOVA, the effect of illumination, temperature, and instrumental music to the number of ouput, number of error, and rating perceived discomfort is significant with the total variance explained of 54,67%, 60,67%, and 75,22% respectively. By using VIKOR method, it yields the optimal combination of experiment 66 with the setting condition of A3-B2-C1-D3. The illumination is 325-350 lux, temperature is 240-260C, fast category of instrumental music, and 70-80 dB for intensity of the music being played.

  9. A Bayesian method to mine spatial data sets to evaluate the vulnerability of human beings to catastrophic risk.

    PubMed

    Li, Lianfa; Wang, Jinfeng; Leung, Hareton; Zhao, Sisi

    2012-06-01

    Vulnerability of human beings exposed to a catastrophic disaster is affected by multiple factors that include hazard intensity, environment, and individual characteristics. The traditional approach to vulnerability assessment, based on the aggregate-area method and unsupervised learning, cannot incorporate spatial information; thus, vulnerability can be only roughly assessed. In this article, we propose Bayesian network (BN) and spatial analysis techniques to mine spatial data sets to evaluate the vulnerability of human beings. In our approach, spatial analysis is leveraged to preprocess the data; for example, kernel density analysis (KDA) and accumulative road cost surface modeling (ARCSM) are employed to quantify the influence of geofeatures on vulnerability and relate such influence to spatial distance. The knowledge- and data-based BN provides a consistent platform to integrate a variety of factors, including those extracted by KDA and ARCSM to model vulnerability uncertainty. We also consider the model's uncertainty and use the Bayesian model average and Occam's Window to average the multiple models obtained by our approach to robust prediction of the risk and vulnerability. We compare our approach with other probabilistic models in the case study of seismic risk and conclude that our approach is a good means to mining spatial data sets for evaluating vulnerability.

  10. hp discontinuous Galerkin methods for the vertical extent of the water column in coastal settings part I: Barotropic forcing

    NASA Astrophysics Data System (ADS)

    Conroy, Colton J.; Kubatko, Ethan J.

    2016-01-01

    In this article, we present novel, high-order, discontinuous Galerkin (DG) methods for the vertical extent of the water column in coastal settings. We examine the shallow water equations (SWE) in the context of DG spatial discretizations coupled with explicit Runge-Kutta (RK) time stepping. All the primary variables, including the free surface elevation, are discretized using discontinuous polynomial spaces of arbitrary order. The difficulty of mismatched lateral boundary faces that accompanies the use of a discontinuous free surface is overcome through the use of a so-called sigma-coordinate system in the vertical, which transforms the bottom boundary and free surface into coordinate surfaces. We develop high-order methods for the SWE that exhibit optimal orders of convergence for all the primary variables via two distinct paths: the first involves the use of a convolution kernel made up of B-splines to filter out errors in the DG discretization of the surface elevation and the corresponding pressure flux. The second involves a method that evaluates the discrete depth-integrated velocity exactly, eliminating the need to solve the depth-integrated momentum equation altogether. The result is a simple and efficient high-order scheme that can be extended to the full three-dimensional SWE.

  11. Multi-criteria decision-making method based on a cross-entropy with interval neutrosophic sets

    NASA Astrophysics Data System (ADS)

    Tian, Zhang-peng; Zhang, Hong-yu; Wang, Jing; Wang, Jian-qiang; Chen, Xiao-hong

    2016-11-01

    In this paper, two optimisation models are established to determine the criterion weights in multi-criteria decision-making situations where knowledge regarding the weight information is incomplete and the criterion values are interval neutrosophic numbers. The proposed approach combines interval neutrosophic sets and TOPSIS, and the closeness coefficients are expressed as interval numbers. Furthermore, the relative likelihood-based comparison relations are constructed to determine the ranking of alternatives. A fuzzy cross-entropy approach is proposed to calculate the discrimination measure between alternatives and the absolute ideal solutions, after a transformation operator has been developed to convert interval neutrosophic numbers into simplified neutrosophic numbers. Finally, an illustrative example is provided, and a comparative analysis is conducted between the approach developed in this paper and other existing methods, to verify the feasibility and effectiveness of the proposed approach.

  12. Numerical simulation of non-viscous liquid pinch off using a coupled level set-boundary integral method

    SciTech Connect

    Garzon, Maria; Sethian, James A.; Gray, Leonard J

    2009-01-01

    Simulations of the pinch off of an inviscid fluid column are carried out based upon a potential flow model with capillary forces. The interface location and the time evolution of the free surface boundary condition are both approximated by means of level set techniques on a fixed domain. The interface velocity is obtained via a Galerkin boundary integral solution of the 3D axisymmetric Laplace equation. A short time analytical solution of the Raleigh-Taylor instability in a liquid column is available, and this result is compared with our numerical experiments to validate the algorithm. The method is capable of handling pinch-off and after pinch-off events, and simulations showing the time evolution of the fluid tube are presented.

  13. Reduction in the divergence of Tomographic P.I.V. results, using the method of Projection Onto Convex Sets

    NASA Astrophysics Data System (ADS)

    Clark, Thomas; Nickels, Timothy

    2010-11-01

    Tomographic P.I.V. allows measurement of fully three-dimensional velocity fields within a region of fluid. Experimental error in the measurement process, combined with the differential nature of the divergence operator results in a large error in the divergence of the results. For incompressible flow, a technique is introduced to reduce the divergence of the output results using the method of Projection Onto Convex Sets (POCS). The "correction" is formulated using a Lagrangian multiplier and implemented through solution of the Poisson equation in a cuboid domain. In this talk, the formulation of the "correction" and the boundary conditions used are presented along with experimental results. Limitations of the technique and possible applications are discussed.

  14. Motion of a semi-infinite bubble in a liquid filled channel using the level set method

    NASA Astrophysics Data System (ADS)

    Tolga Akcabay, Deniz; Halpern, David; Grotberg, James B.

    2008-11-01

    The study of plug propagation in lung airways is of interest in the treatment of medical conditions such as asthma and in drug delivery. The problem of a semi-infinite bubble steadily displacing a liquid in a 2D channel (planar Bretherton problem) is computed using a fractional-step method on a Cartesian grid to solve the Navier-Stokes equations and a level-set formulation for resolving the air-liquid interface. We matched with available literature the geometry of the front and rear menisci of this semi-infinite bubble, stresses on the channel walls, and the maximum pressure drop as a function of the Capillary number -- the ratio of viscous to surface tension effects. Furthermore, we present preliminary results for flows within tapered walls to address area expansion near airway bifurcations.

  15. Chemomechanical caries removal method versus mechanical caries removal methods in clinical and community-based setting: A comparative in vivo study

    PubMed Central

    Kumar, K. V. K. Santosh; Prasad, M. Ghanashyam; Sandeep, R. Venkata; Reddy, S. Pavani; Divya, D.; Pratyusha, K.

    2016-01-01

    Objective: To compare the effectiveness of various caries removal techniques in mandibular primary molars using Smart Burs, atraumatic restorative technique (ART) (mechanical caries removal) and Carie-care (chemomechanical caries removal [CMCR]) among primary school children in clinical and community-based settings. Materials and Methods: A total of 80 carious primary mandibular molars were selected for the study from the dental clinic and community. They were equally assigned to four groups according to caries removal technique and also by the operating site. In Group 1, caries was removed using Carie-care in the dental clinic and in Group 2, with Smart Burs in the dental clinic. In Group 3, caries was removed using Carie-care in the field and in Group 4, with the ART in the field. The time taken for caries removal, the efficacy of caries removal and patient acceptance were evaluated with different caries removal techniques. Statistical Analysis: The obtained data were subjected to statistical analysis by ANOVA test. Results: In clinical settings, Carie-care was time-consuming but was more efficient with increased acceptance than Smart Burs and the result was found to be significant statistically (P < 0.05). In community-based settings, Carie-care was more efficient, less time consuming, and showed an increased acceptance when compared to atraumatic restorative treatment and the result was found to be significant statistically (P < 0.05). Conclusions: The CMCR technique was superior to the mechanical caries removal technique in primary teeth among school children in terms of time, efficacy, and acceptance in both clinical- and community-based settings. PMID:27403059

  16. Extending the African instrumental record to the early 19th century

    SciTech Connect

    Nicholson, S.E.

    1997-11-01

    This paper describes progress toward the production of a data set that extends the African climate record back to the beginning of the 19th century. Qualitative documentary evidence, lake-level fluctuations and other proxy indicators are combined with historical rainfall records to produce regional time series. The data set has relatively high temporal and spatial resolution. The conceptualization is based on a climatic regionalization produced using modern data and an anomaly method in previous historical reconstructions. The data set provides information for some 100 regions with a 1 to 5 year resolution for most of the nineteenth century. Three to five quantitative classes of rainfall are utilized in the data set. Here, the available information to produce this record is summarized. The methodology utilized to combine proxy data and observations to produce a quantitative rainfall data set is described. This historical data set is compared with actual rainfall records for select regions where both are available. This comparison indicates the reliability of the proxy African data set. An analysis of the historical record indicates that the main characteristics of rainfall variability evident in the modern African record are also apparent in the 19th century record. 5 figs.

  17. Calculation of contact angles at triple phase boundary in solid oxide fuel cell anode using the level set method

    SciTech Connect

    Sun, Xiaojun; Hasegawa, Yosuke; Kohno, Haruhiko; Jiao, Zhenjun; Hayakawa, Koji; Okita, Kohei; Shikazono, Naoki

    2014-10-15

    A level set method is applied to characterize the three dimensional structures of nickel, yttria stabilized zirconia and pore phases in solid oxide fuel cell anode reconstructed by focused ion beam-scanning electron microscope. A numerical algorithm is developed to evaluate the contact angles at the triple phase boundary based on interfacial normal vectors which can be calculated from the signed distance functions defined for each of the three phases. Furthermore, surface tension force is estimated from the contact angles by assuming the interfacial force balance at the triple phase boundary. The average contact angle values of nickel, yttria stabilized zirconia and pore are found to be 143°–156°, 83°–138° and 82°–123°, respectively. The mean contact angles remained nearly unchanged after 100 hour operation. However, the contact angles just after reduction are different for the cells with different sintering temperatures. In addition, standard deviations of the contact angles are very large especially for yttria stabilized zirconia and pore phases. The calculated surface tension forces from mean contact angles were close to the experimental values found in the literature. Slight increase of surface tensions of nickel/pore and nickel/yttria stabilized zirconia were observed after operation. Present data are expected to be used not only for the understanding of the degradation mechanism, but also for the quantitative prediction of the microstructural temporal evolution of solid oxide fuel cell anode. - Highlights: • A level set method is applied to characterize the 3D structures of SOFC anode. • A numerical algorithm is developed to evaluate the contact angles at the TPB. • Surface tension force is estimated from the contact angles. • The average contact angle values are found to be 143o-156o, 83o-138o and 82o-123o. • Present data are expected to understand degradation and predict evolution of SOFC.

  18. LV wall segmentation using the variational level set method (LSM) with additional shape constraint for oedema quantification.

    PubMed

    Kadir, K; Gao, H; Payne, A; Soraghan, J; Berry, C

    2012-10-01

    In this paper an automatic algorithm for the left ventricle (LV) wall segmentation and oedema quantification from T2-weighted cardiac magnetic resonance (CMR) images is presented. The extent of myocardial oedema delineates the ischaemic area-at-risk (AAR) after myocardial infarction (MI). Since AAR can be used to estimate the amount of salvageable myocardial post-MI, oedema imaging has potential clinical utility in the management of acute MI patients. This paper presents a new scheme based on the variational level set method (LSM) with additional shape constraint for the segmentation of T2-weighted CMR image. In our approach, shape information of the myocardial wall is utilized to introduce a shape feature of the myocardial wall into the variational level set formulation. The performance of the method is tested using real CMR images (12 patients) and the results of the automatic system are compared to manual segmentation. The mean perpendicular distances between the automatic and manual LV wall boundaries are in the range of 1-2 mm. Bland-Altman analysis on LV wall area indicates there is no consistent bias as a function of LV wall area, with a mean bias of -121 mm(2) between individual investigator one (IV1) and LSM, and -122 mm(2) between individual investigator two (IV2) and LSM when compared to two investigators. Furthermore, the oedema quantification demonstrates good correlation when compared to an expert with an average error of 9.3% for 69 slices of short axis CMR image from 12 patients.

  19. Association between Food Insecurity and Procurement Methods among People Living with HIV in a High Resource Setting

    PubMed Central

    Anema, Aranka; Fielden, Sarah J.; Shurgold, Susan; Ding, Erin; Messina, Jennifer; Jones, Jennifer E.; Chittock, Brian; Monteith, Ken; Globerman, Jason; Rourke, Sean B.; Hogg, Robert S.

    2016-01-01

    Objective People living with HIV in high-resource settings suffer severe levels of food insecurity; however, limited evidence exists regarding dietary intake and sub-components that characterize food insecurity (i.e. food quantity, quality, safety or procurement) in this population. We examined the prevalence and characteristics of food insecurity among people living with HIV across British Columbia, Canada. Design This cross-sectional analysis was conducted within a national community-based research initiative. Methods Food security was measured using the Health Canada Household Food Security Scale Module. Logistic regression was used to determine key independent predictors of food insecurity, controlling for potential confounders. Results Of 262 participants, 192 (73%) reported food insecurity. Sub-components associated with food insecurity in bivariate analysis included: < RDI consumption of protein (p = 0.046); being sick from spoiled/unsafe food in the past six months (p = 0.010); and procurement of food using non-traditional methods (p <0.05). In multivariable analyses, factors significantly associated with food insecurity included: procurement of food using non-traditional methods [AOR = 11.11, 95% CI: 4.79–25.68, p = <0.001]; younger age [AOR = 0.92, 95% CI: 0.86–0.96, p = <0.001]; unstable housing [AOR = 4.46, 95% CI: 1.15–17.36, p = 0.031]; household gross annual income [AOR = 4.49, 95% CI: 1.74–11.60, p = 0.002]; and symptoms of depression [AOR = 2.73, 95% CI: 1.25–5.96, p = 0.012]. Conclusions Food insecurity among people living with HIV in British Columbia is characterized by poor dietary quality and food procurement methods. Notably, participants who reported procuring in non-traditional manners were over 10 times more likely to be food insecure. These findings suggest a need for tailored food security and social support interventions in this setting. PMID:27487041

  20. 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…

  1. 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.…

  2. Testing and validating a modified CTAB DNA extraction method to enable molecular parentage analysis of fertilized eggs and larvae of an emerging South African aquaculture species, the dusky kob Argyrosomus japonicus.

    PubMed

    Mirimin, L; Roodt-Wilding, R

    2015-03-01

    This study describes the successful implementation of a modified cetyltrimethyl ammonium bromide (CTAB) protocol to isolate genomic DNA and amplify 14 microsatellite markers from fertilized eggs and larvae of an emerging South African farmed marine fish species, the dusky kob Argyrosomus japonicus. To test and validate the efficiency of this method, genetic data were utilized to resolve parentage and kinship of first-generation (F1) offspring produced in mass-spawning events of wild broodstock fish in a commercial hatchery.

  3. 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

  4. Novel level-set based segmentation method of the lung at HRCT images of diffuse interstitial lung disease (DILD)

    NASA Astrophysics Data System (ADS)

    Lee, Jeongjin; Seo, Joon Beom; Kim, Namkug; Park, Sang Ok; Lee, Ho; Shin, Yeong Gil; Kim, Soo-Hong

    2009-02-01

    In this paper, we propose an algorithm for reliable segmentation of the lung at HRCT of DILD. Our method consists of four main steps. First, the airway and colon are segmented and excluded by thresholding(-974 HU) and connected component analysis. Second, initial lung is identified by thresholding(-474 HU). Third, shape propagation outward the lung is performed on the initial lung. Actual lung boundaries exist inside the propagated boundaries. Finally, subsequent shape modeling level-set inward the lung from the propagated boundary can identify the lung boundary when the curvature term was highly weighted. To assess the accuracy of the proposed algorithm, the segmentation results of 54 patients are compared with those of manual segmentation done by an expert radiologist. The value of 1 minus volumetric overlap is less than 5% error. Accurate result of our method would be useful in determining the lung parenchyma at HRCT, which is the essential step for the automatic classification and quantification of diffuse interstitial lung disease.

  5. Mechanical behavior of pathological and normal red blood cells in microvascular flow based on modified level-set method

    NASA Astrophysics Data System (ADS)

    Zhang, XiWen; Ma, FangChao; Hao, PengFei; Yao, ZhaoHui

    2016-01-01

    The research of the motion and deformation of the RBCs is important to reveal the mechanism of blood diseases. A numerical method has been developed with level set formulation for elastic membrane immersed in incompressible fluid. The numerical model satisfies mass and energy conservation without the leaking problems in classical Immersed Boundary Method (IBM), at the same time, computing grid we used can be much smaller than the general literatures. The motion and deformation of a red blood cell (including pathological & normal status) in microvascular flow are simulated. It is found that the Reynolds number and membrane's stiffness play an important role in the transmutation and oscillation of the elastic membrane. The normal biconcave shape of the RBC is propitious to create high deformation than other pathological shapes. With reduced viscosity of the interior fluid both the velocity of the blood and the deformability of the cell reduced. With increased viscosity of the plasma both the velocity of the blood and the deformability of the cell reduced. The tank treading of the RBC membrane is observed at low enough viscosity contrast in shear flow. The tank tread fixed inclination angle of the cell depends on the shear ratio and viscosity contrast, which can be compared with the experimental observation well.

  6. Flexible and scalable methods for quantifying stochastic variability in the era of massive time-domain astronomical data sets

    SciTech Connect

    Kelly, Brandon C.; Becker, Andrew C.; Sobolewska, Malgosia; Siemiginowska, Aneta; Uttley, Phil

    2014-06-10

    We present the use of continuous-time autoregressive moving average (CARMA) models as a method for estimating the variability features of a light curve, and in particular its power spectral density (PSD). CARMA models fully account for irregular sampling and measurement errors, making them valuable for quantifying variability, forecasting and interpolating light curves, and variability-based classification. We show that the PSD of a CARMA model can be expressed as a sum of Lorentzian functions, which makes them extremely flexible and able to model a broad range of PSDs. We present the likelihood function for light curves sampled from CARMA processes, placing them on a statistically rigorous foundation, and we present a Bayesian method to infer the probability distribution of the PSD given the measured light curve. Because calculation of the likelihood function scales linearly with the number of data points, CARMA modeling scales to current and future massive time-domain data sets. We conclude by applying our CARMA modeling approach to light curves for an X-ray binary, two active galactic nuclei, a long-period variable star, and an RR Lyrae star in order to illustrate their use, applicability, and interpretation.

  7. Watching Transitions Unfold: A Mixed-Method Study of Transitions within Early Childhood Care and Education Settings

    ERIC Educational Resources Information Center

    O'Farrelly, Christine; Hennessy, Eilis

    2014-01-01

    Unlike the transitions children make between settings, those they undertake between age groups within early childhood care and education (ECCE) settings are seldom studied. Accordingly, this exploratory study followed seven preschool children (three boys and four girls) as they moved to new rooms in five ECCE settings. Structured observations of…

  8. The South Asian Heart Lifestyle Intervention (SAHELI) study to improve cardiovascular risk factors in a community setting: design and methods.

    PubMed

    Kandula, Namratha R; Patel, Yasin; Dave, Swapna; Seguil, Paola; Kumar, Santosh; Baker, David W; Spring, Bonnie; Siddique, Juned

    2013-11-01

    Disseminating and implementing evidence-based, cardiovascular disease (CVD) prevention lifestyle interventions in community settings and in ethnic minority populations is a challenge. We describe the design and methods for the South Asian Heart Lifestyle Intervention (SAHELI) study, a pilot study designed to determine the feasibility and initial efficacy of a culturally-targeted, community-based lifestyle intervention to improve physical activity and diet behaviors among medically underserved South Asians (SAs). Participants with at least one CVD risk factor will be randomized to either a lifestyle intervention or a control group. Participants in both groups will be screened in a community setting and receive a primary care referral after randomization. Intervention participants will receive 6weeks of group classes, followed by 12weeks of individual telephone support where they will be encouraged to initiate and maintain a healthy lifestyle goal. Control participants will receive their screening results and monthly mailings on CVD prevention. Primary outcomes will be changes in moderate/vigorous physical activity and saturated fat intake between baseline, 3-, and 6-month follow-up. Secondary outcomes will be changes in weight, clinical risk factors, primary care visits, self-efficacy, and social support. This study will be one of the first to pilot-test a lifestyle intervention for SAs, one of the fastest growing racial/ethnic groups in the U.S. and one with disparate CVD risk. Results of this pilot study will provide preliminary data about the efficacy of a lifestyle intervention on CVD risk in SAs and inform community-engaged CVD prevention efforts in an increasingly diverse U.S. population.

  9. Birth control method choice and use of barrier methods for sexually transmitted disease prevention among low-income African-American women.

    PubMed

    Macaluso, M; Cheng, H; Akers, R

    2000-07-01

    In a prospective study of 1122 women attending a sexually transmitted disease (STD) clinic in Alabama, consistent use of the male condom and vaginal microbicide/spermicides was promoted to reduce STD risk. This analysis evaluated: 1) baseline characteristics that may influence birth control method choice; and 2) the association of birth control method and other baseline characteristics with consistency of barrier use during follow up. Birth control method was associated with sociodemographic variables, sexual, and reproductive history. Women who adopted user-independent methods (tubal ligation, implants, injectable hormones) appear to have completed their family plan. Oral contraceptive users were of higher socioeconomic status and at lower STD risk. Barrier method users and women who used no method were young and at higher STD risk. Consistency of condom/spermicide use increased in all groups. Barrier method users were more likely than other women to use condoms and spermicides during the study. Women who used no birth control method at baseline experienced the largest increase in barrier use during follow up, although their barrier use rates were lower than in other groups. The synergism between the intention to prevent pregnancy and the intention to prevent STD should be considered in the design of interventions promoting condom use.

  10. Diagnostic Accuracy of the Small Membrane Filtration Method for Diagnosis of Pulmonary Tuberculosis in a High-HIV-Prevalence Setting.

    PubMed

    Boum, Yap; Kim, Soyeon; Orikiriza, Patrick; Acuña-Villaorduña, Carlos; Vinhas, Solange; Bonnet, Maryline; Nyehangane, Dan; Mwanga-Amumpaire, Juliet; Fennelly, Kevin P; Jones-López, Edward C

    2016-06-01

    Sputum acid-fast bacilli (AFB) smear microscopy has suboptimal sensitivity but remains the most commonly used laboratory test to diagnose pulmonary tuberculosis (TB). We prospectively evaluated the small membrane filtration (SMF) method that concentrates AFB in a smaller area to facilitate detection to improve the diagnostic performance of microscopy. We enrolled adults with suspicion of pulmonary TB from health facilities in southwestern Uganda. Clinical history, physical examination, and 3 sputum samples were obtained for direct fluorescent AFB smear, SMF, Xpert MTB/RIF, and MGIT culture media. Sensitivity and specificity were estimated for SMF, AFB smear, and Xpert MTB/RIF, using MGIT as the reference standard. The analysis was stratified according to HIV status. From September 2012 to April 2014, 737 participants were included in the HIV-infected stratum (146 [20.5%] were culture positive) and 313 were in the HIV-uninfected stratum (85 [28%] were culture positive). In HIV-infected patients, the sensitivity of a single SMF was 67.4% (95% confidence interval [CI], 59.9% to 74.1%); for AFB, 68.0% (95% CI, 60.6% to 74.6%); and for Xpert MTB/RIF, 91.0% (95% CI, 85.0% to 94.8%). In HIV-uninfected patients, the corresponding sensitivities were 72.5% (95% CI, 62.1% to 80.9%), 80.3% (95% CI, 70.8% to 87.2%), and 93.5% (95% CI, 85.7% to 97.2%). The specificity for all 3 tests in both HIV groups was ≥96%. In this setting, the SMF method did not improve the diagnostic accuracy of sputum AFB. The Xpert MTB/RIF assay performed well in both HIV-infected and -uninfected groups.

  11. Multilocus Phylogeography and Species Delimitation in the Cumberland Plateau Salamander, Plethodon kentucki: Incongruence among Data Sets and Methods

    PubMed Central

    Kuchta, Shawn R.; Brown, Ashley D.; Converse, Paul E.; Highton, Richard

    2016-01-01

    Species are a fundamental unit of biodiversity, yet can be challenging to delimit objectively. This is particularly true of species complexes characterized by high levels of population genetic structure, hybridization between genetic groups, isolation by distance, and limited phenotypic variation. Previous work on the Cumberland Plateau Salamander, Plethodon kentucki, suggested that it might constitute a species complex despite occupying a relatively small geographic range. To examine this hypothesis, we sampled 135 individuals from 43 populations, and used four mitochondrial loci and five nuclear loci (5693 base pairs) to quantify phylogeographic structure and probe for cryptic species diversity. Rates of evolution for each locus were inferred using the multidistribute package, and time calibrated gene trees and species trees were inferred using BEAST 2 and *BEAST 2, respectively. Because the parameter space relevant for species delimitation is large and complex, and all methods make simplifying assumptions that may lead them to fail, we conducted an array of analyses. Our assumption was that strongly supported species would be congruent across methods. Putative species were first delimited using a Bayesian implementation of the GMYC model (bGMYC), Geneland, and Brownie. We then validated these species using the genealogical sorting index and BPP. We found substantial phylogeographic diversity using mtDNA, including four divergent clades and an inferred common ancestor at 14.9 myr (95% HPD: 10.8–19.7 myr). By contrast, this diversity was not corroborated by nuclear sequence data, which exhibited low levels of variation and weak phylogeographic structure. Species trees estimated a far younger root than did the mtDNA data, closer to 1.0 myr old. Mutually exclusive putative species were identified by the different approaches. Possible causes of data set discordance, and the problem of species delimitation in complexes with high levels of population structure and

  12. Diagnostic Accuracy of the Small Membrane Filtration Method for Diagnosis of Pulmonary Tuberculosis in a High-HIV-Prevalence Setting.

    PubMed

    Boum, Yap; Kim, Soyeon; Orikiriza, Patrick; Acuña-Villaorduña, Carlos; Vinhas, Solange; Bonnet, Maryline; Nyehangane, Dan; Mwanga-Amumpaire, Juliet; Fennelly, Kevin P; Jones-López, Edward C

    2016-06-01

    Sputum acid-fast bacilli (AFB) smear microscopy has suboptimal sensitivity but remains the most commonly used laboratory test to diagnose pulmonary tuberculosis (TB). We prospectively evaluated the small membrane filtration (SMF) method that concentrates AFB in a smaller area to facilitate detection to improve the diagnostic performance of microscopy. We enrolled adults with suspicion of pulmonary TB from health facilities in southwestern Uganda. Clinical history, physical examination, and 3 sputum samples were obtained for direct fluorescent AFB smear, SMF, Xpert MTB/RIF, and MGIT culture media. Sensitivity and specificity were estimated for SMF, AFB smear, and Xpert MTB/RIF, using MGIT as the reference standard. The analysis was stratified according to HIV status. From September 2012 to April 2014, 737 participants were included in the HIV-infected stratum (146 [20.5%] were culture positive) and 313 were in the HIV-uninfected stratum (85 [28%] were culture positive). In HIV-infected patients, the sensitivity of a single SMF was 67.4% (95% confidence interval [CI], 59.9% to 74.1%); for AFB, 68.0% (95% CI, 60.6% to 74.6%); and for Xpert MTB/RIF, 91.0% (95% CI, 85.0% to 94.8%). In HIV-uninfected patients, the corresponding sensitivities were 72.5% (95% CI, 62.1% to 80.9%), 80.3% (95% CI, 70.8% to 87.2%), and 93.5% (95% CI, 85.7% to 97.2%). The specificity for all 3 tests in both HIV groups was ≥96%. In this setting, the SMF method did not improve the diagnostic accuracy of sputum AFB. The Xpert MTB/RIF assay performed well in both HIV-infected and -uninfected groups. PMID:27030493

  13. Multilocus Phylogeography and Species Delimitation in the Cumberland Plateau Salamander, Plethodon kentucki: Incongruence among Data Sets and Methods.

    PubMed

    Kuchta, Shawn R; Brown, Ashley D; Converse, Paul E; Highton, Richard

    2016-01-01

    Species are a fundamental unit of biodiversity, yet can be challenging to delimit objectively. This is particularly true of species complexes characterized by high levels of population genetic structure, hybridization between genetic groups, isolation by distance, and limited phenotypic variation. Previous work on the Cumberland Plateau Salamander, Plethodon kentucki, suggested that it might constitute a species complex despite occupying a relatively small geographic range. To examine this hypothesis, we sampled 135 individuals from 43 populations, and used four mitochondrial loci and five nuclear loci (5693 base pairs) to quantify phylogeographic structure and probe for cryptic species diversity. Rates of evolution for each locus were inferred using the multidistribute package, and time calibrated gene trees and species trees were inferred using BEAST 2 and *BEAST 2, respectively. Because the parameter space relevant for species delimitation is large and complex, and all methods make simplifying assumptions that may lead them to fail, we conducted an array of analyses. Our assumption was that strongly supported species would be congruent across methods. Putative species were first delimited using a Bayesian implementation of the GMYC model (bGMYC), Geneland, and Brownie. We then validated these species using the genealogical sorting index and BPP. We found substantial phylogeographic diversity using mtDNA, including four divergent clades and an inferred common ancestor at 14.9 myr (95% HPD: 10.8-19.7 myr). By contrast, this diversity was not corroborated by nuclear sequence data, which exhibited low levels of variation and weak phylogeographic structure. Species trees estimated a far younger root than did the mtDNA data, closer to 1.0 myr old. Mutually exclusive putative species were identified by the different approaches. Possible causes of data set discordance, and the problem of species delimitation in complexes with high levels of population structure and

  14. Multilocus Phylogeography and Species Delimitation in the Cumberland Plateau Salamander, Plethodon kentucki: Incongruence among Data Sets and Methods.

    PubMed

    Kuchta, Shawn R; Brown, Ashley D; Converse, Paul E; Highton, Richard

    2016-01-01

    Species are a fundamental unit of biodiversity, yet can be challenging to delimit objectively. This is particularly true of species complexes characterized by high levels of population genetic structure, hybridization between genetic groups, isolation by distance, and limited phenotypic variation. Previous work on the Cumberland Plateau Salamander, Plethodon kentucki, suggested that it might constitute a species complex despite occupying a relatively small geographic range. To examine this hypothesis, we sampled 135 individuals from 43 populations, and used four mitochondrial loci and five nuclear loci (5693 base pairs) to quantify phylogeographic structure and probe for cryptic species diversity. Rates of evolution for each locus were inferred using the multidistribute package, and time calibrated gene trees and species trees were inferred using BEAST 2 and *BEAST 2, respectively. Because the parameter space relevant for species delimitation is large and complex, and all methods make simplifying assumptions that may lead them to fail, we conducted an array of analyses. Our assumption was that strongly supported species would be congruent across methods. Putative species were first delimited using a Bayesian implementation of the GMYC model (bGMYC), Geneland, and Brownie. We then validated these species using the genealogical sorting index and BPP. We found substantial phylogeographic diversity using mtDNA, including four divergent clades and an inferred common ancestor at 14.9 myr (95% HPD: 10.8-19.7 myr). By contrast, this diversity was not corroborated by nuclear sequence data, which exhibited low levels of variation and weak phylogeographic structure. Species trees estimated a far younger root than did the mtDNA data, closer to 1.0 myr old. Mutually exclusive putative species were identified by the different approaches. Possible causes of data set discordance, and the problem of species delimitation in complexes with high levels of population structure and

  15. Using Frequent Item Set Mining and Feature Selection Methods to Identify Interacted Risk Factors - The Atrial Fibrillation Case Study.

    PubMed

    Li, Xiang; Liu, Haifeng; Du, Xin; Hu, Gang; Xie, Guotong; Zhang, Ping

    2016-01-01

    Disease risk prediction is highly important for early intervention and treatment, and identification of predictive risk factors is the key point to achieve accurate prediction. In addition to original independent features in a dataset, some interacted features, such as comorbidities and combination therapies, may have non-additive influence on the disease outcome and can also be used in risk prediction to improve the prediction performance. However, it is usually difficult to manually identify the possible interacted risk factors due to the combination explosion of features. In this paper, we propose an automatic approach to identify predictive risk factors with interactions using frequent item set mining and feature selection methods. The proposed approach was applied in the real world case study of predicting ischemic stroke and thromboembolism for atrial fibrillation patients on the Chinese atrial fibrillation registry dataset, and the results show that our approach can not only improve the prediction performance, but also identify the comorbidities and combination therapies that have potential influences on TE occurrence for AF. PMID:27577446

  16. Web-MCQ: a set of methods and freely available open source code for administering online multiple choice question assessments.

    PubMed

    Hewson, Claire

    2007-08-01

    E-learning approaches have received increasing attention in recent years. Accordingly, a number of tools have become available to assist the nonexpert computer user in constructing and managing virtual learning environments, and implementing computer-based and/or online procedures to support pedagogy. Both commercial and free packages are now available, with new developments emerging periodically. Commercial products have the advantage of being comprehensive and reliable, but tend to require substantial financial investment and are not always transparent to use. They may also restrict pedagogical choices due to their predetermined ranges of functionality. With these issues in mind, several authors have argued for the pedagogical benefits of developing freely available, open source e-learning resources, which can be shared and further developed within a community of educational practitioners. The present paper supports this objective by presenting a set of methods, along with supporting freely available, downloadable, open source programming code, to allow administration of online multiple choice question assessments to students.

  17. On the use of the resting potential and level set methods for identifying ischemic heart disease: An inverse problem

    NASA Astrophysics Data System (ADS)

    Nielsen, Bjørn Fredrik; Lysaker, Marius; Tveito, Aslak

    2007-01-01

    The electrical activity in the heart is modeled by a complex, nonlinear, fully coupled system of differential equations. Several scientists have studied how this model, referred to as the bidomain model, can be modified to incorporate the effect of heart infarctions on simulated ECG (electrocardiogram) recordings. We are concerned with the associated inverse problem; how can we use ECG recordings and mathematical models to identify the position, size and shape of heart infarctions? Due to the extreme CPU efforts needed to solve the bidomain equations, this model, in its full complexity, is not well-suited for this kind of problems. In this paper we show how biological knowledge about the resting potential in the heart and level set techniques can be combined to derive a suitable stationary model, expressed in terms of an elliptic PDE, for such applications. This approach leads to a nonlinear ill-posed minimization problem, which we propose to regularize and solve with a simple iterative scheme. Finally, our theoretical findings are illuminated through a series of computer simulations for an experimental setup involving a realistic heart in torso geometry. More specifically, experiments with synthetic ECG recordings, produced by solving the bidomain model, indicate that our method manages to identify the physical characteristics of the ischemic region(s) in the heart. Furthermore, the ill-posed nature of this inverse problem is explored, i.e. several quantitative issues of our scheme are explored.

  18. Assessing health impacts in complex eco-epidemiological settings in the humid tropics: Advancing tools and methods

    SciTech Connect

    Winkler, Mirko S.; Divall, Mark J.; Krieger, Gary R.; Balge, Marci Z.; Singer, Burton H.; Utzinger, Juerg

    2010-01-15

    In the developing world, large-scale projects in the extractive industry and natural resources sectors are often controversial and associated with long-term adverse health consequences to local communities. In many industrialised countries, health impact assessment (HIA) has been institutionalized for the mitigation of anticipated negative health effects while enhancing the benefits of projects, programmes and policies. However, in developing country settings, relatively few HIAs have been performed. Hence, more HIAs with a focus on low- and middle-income countries are needed to advance and refine tools and methods for impact assessment and subsequent mitigation measures. We present a promising HIA approach, developed within the frame of a large gold-mining project in the Democratic Republic of the Congo. The articulation of environmental health areas, the spatial delineation of potentially affected communities and the use of a diversity of sources to obtain quality baseline health data are utilized for risk profiling. We demonstrate how these tools and data are fed into a risk analysis matrix, which facilitates ranking of potential health impacts for subsequent prioritization of mitigation strategies. The outcomes encapsulate a multitude of environmental and health determinants in a systematic manner, and will assist decision-makers in the development of mitigation measures that minimize potential adverse health effects and enhance positive ones.

  19. African American English: Implications for School Counseling Professionals

    ERIC Educational Resources Information Center

    Day-Vines, Norma L.; Barto, Heather H.; Booker, Beverly L.; Smith, Kim V.; Barna, Jennifer; Maiden, Brian S.; Zegley, Linda; Felder, Monique T.

    2009-01-01

    African American English (AAE) refers to the systematic, rule-governed linguistic patterns of found among African Americans. This article provides an overview of AAE. More specifically, the article enumerates the historical underpinnings associated with AAE, identifies a representative set of AAE characteristics, reviews relevant research, and…

  20. Food Group Categories of Low-Income African American Women

    ERIC Educational Resources Information Center

    Lynch, Elizabeth B.; Holmes, Shane

    2011-01-01

    Objective: Describe lay food group categories of low-income African American women and assess the overlap of lay food groups and MyPyramid food groups. Design: A convenience sample of African American mothers from a low-income Chicago neighborhood performed a card-sorting task in which they grouped familiar food items into food groups. Setting:…

  1. Novel recurrently mutated genes in African American colon cancers

    PubMed Central

    Guda, Kishore; Veigl, Martina L.; Varadan, Vinay; Nosrati, Arman; Ravi, Lakshmeswari; Lutterbaugh, James; Beard, Lydia; Willson, James K. V.; Sedwick, W. David; Wang, Zhenghe John; Molyneaux, Neil; Miron, Alexander; Adams, Mark D.; Elston, Robert C.; Markowitz, Sanford D.; Willis, Joseph E.

    2015-01-01

    We used whole-exome and targeted sequencing to characterize somatic mutations in 103 colorectal cancers (CRC) from African Americans, identifying 20 new genes as significantly mutated in CRC. Resequencing 129 Caucasian derived CRCs confirmed a 15-gene set as a preferential target for mutations in African American CRCs. Two predominant genes, ephrin type A receptor 6 (EPHA6) and folliculin (FLCN), with mutations exclusive to African American CRCs, are by genetic and biological criteria highly likely African American CRC driver genes. These previously unsuspected differences in the mutational landscapes of CRCs arising among individuals of different ethnicities have potential to impact on broader disparities in cancer behaviors. PMID:25583493

  2. Novel recurrently mutated genes in African American colon cancers.

    PubMed

    Guda, Kishore; Veigl, Martina L; Varadan, Vinay; Nosrati, Arman; Ravi, Lakshmeswari; Lutterbaugh, James; Beard, Lydia; Willson, James K V; Sedwick, W David; Wang, Zhenghe John; Molyneaux, Neil; Miron, Alexander; Adams, Mark D; Elston, Robert C; Markowitz, Sanford D; Willis, Joseph E

    2015-01-27

    We used whole-exome and targeted sequencing to characterize somatic mutations in 103 colorectal cancers (CRC) from African Americans, identifying 20 new genes as significantly mutated in CRC. Resequencing 129 Caucasian derived CRCs confirmed a 15-gene set as a preferential target for mutations in African American CRCs. Two predominant genes, ephrin type A receptor 6 (EPHA6) and folliculin (FLCN), with mutations exclusive to African American CRCs, are by genetic and biological criteria highly likely African American CRC driver genes. These previously unsuspected differences in the mutational landscapes of CRCs arising among individuals of different ethnicities have potential to impact on broader disparities in cancer behaviors. PMID:25583493

  3. The Development of an African-Centered School--The First 20 Years

    ERIC Educational Resources Information Center

    Squire, Michelle Suzette

    2012-01-01

    This research study is a case study of the development of an African-centered school over a 20-year period. The study describes how the kindergarten-through-eighth-grade institution was established. Interview questions focused on: 1. Establishment of an African-centered institution 2. Challenges of setting up an African-centered institution 3.…

  4. Assessing Dispositions in Pre-Service Teachers: Does Setting or Experience Affect Dispositions? A Mixed-Methods Study

    ERIC Educational Resources Information Center

    Frederiksen, Heidi

    2010-01-01

    The purpose of this study was to determine whether there was a significant difference between the perceived dispositions in pre-service teachers in urban settings versus non-urban settings. It was also the intent of this study to describe the change in perceived dispositions throughout pre-service teachers' internship experiences. Graduate…

  5. 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

  6. H.U.B city steps: methods and early findings from a community-based participatory research trial to reduce blood pressure among african americans

    PubMed Central

    2011-01-01

    Background Community-based participatory research (CBPR) has been recognized as an important approach to develop and execute health interventions among marginalized populations, and a key strategy to translate research into practice to help reduce health disparities. Despite growing interest in the CBPR approach, CBPR initiatives rarely use experimental or other rigorous research designs to evaluate health outcomes. This behavioral study describes the conceptual frameworks, methods, and early findings related to the reach, adoption, implementation, and effectiveness on primary blood pressure outcomes. Methods The CBPR, social support, and motivational interviewing frameworks are applied to test treatment effects of a two-phased CBPR walking intervention, including a 6-month active intervention quasi experimental phase and 12-month maintenance randomized controlled trial phase to test dose effects of motivational interviewing. A community advisory board helped develop and execute the culturally-appropriate intervention components which included social support walking groups led by peer coaches, pedometer diary self-monitoring, monthly diet and physical activity education sessions, and individualized motivational interviewing sessions. Although the study is on-going, three month data is available and reported. Analyses include descriptive statistics and paired t tests. Results Of 269 enrolled participants, most were African American (94%) females (85%) with a mean age of 43.8 (SD = 12.1) years. Across the 3 months, 90% of all possible pedometer diaries were submitted. Attendance at the monthly education sessions was approximately 33%. At the 3-month follow-up 227 (84%) participants were retained. From baseline to 3-months, systolic BP [126.0 (SD = 19.1) to 120.3 (SD = 17.9) mmHg; p < 0.001] and diastolic BP [83. 2 (SD = 12.3) to 80.2 (SD = 11.6) mmHg; p < 0.001] were significantly reduced. Conclusions This CBPR study highlights implementation factors and signifies

  7. Approaching the complete basis set limit of CCSD(T) for large systems by the third-order incremental dual-basis set zero-buffer F12 method

    SciTech Connect

    Zhang, Jun Dolg, Michael

    2014-01-28

    The third-order incremental dual-basis set zero-buffer approach was combined with CCSD(T)-F12x (x = a, b) theory to develop a new approach, i.e., the inc3-db-B0-CCSD(T)-F12 method, which can be applied as a black-box procedure to efficiently obtain the near complete basis set (CBS) limit of the CCSD(T) energies also for large systems. We tested this method for several cases of different chemical nature: four complexes taken from the standard benchmark sets S66 and X40, the energy difference between isomers of water hexamer and the rotation barrier of biphenyl. The results show that our method has an error relative to the best estimation of CBS energy of only 0.2 kcal/mol or less. By parallelization, our method can accomplish the CCSD(T)-F12 calculations of about 60 correlated electrons and 800 basis functions in only several days, which by standard implementation are impossible for ordinary hardware. We conclude that the inc3-db-B0-CCSD(T)-F12a/AVTZ method, which is of CCSD(T)/AV5Z quality, is close to the limit of accuracy that one can achieve for large systems currently.

  8. Data Rods: High Speed, Time-Series Analysis of Massive Cryospheric Data Sets Using Object-Oriented Database Methods

    NASA Astrophysics Data System (ADS)

    Liang, Y.; Gallaher, D. W.; Grant, G.; Lv, Q.

    2011-12-01

    Change over time, is the central driver of climate change detection. The goal is to diagnose the underlying causes, and make projections into the future. In an effort to optimize this process we have developed the Data Rod model, an object-oriented approach that provides the ability to query grid cell changes and their relationships to neighboring grid cells through time. The time series data is organized in time-centric structures called "data rods." A single data rod can be pictured as the multi-spectral data history at one grid cell: a vertical column of data through time. This resolves the long-standing problem of managing time-series data and opens new possibilities for temporal data analysis. This structure enables rapid time- centric analysis at any grid cell across multiple sensors and satellite platforms. Collections of data rods can be spatially and temporally filtered, statistically analyzed, and aggregated for use with pattern matching algorithms. Likewise, individual image pixels can be extracted to generate multi-spectral imagery at any spatial and temporal location. The Data Rods project has created a series of prototype databases to store and analyze massive datasets containing multi-modality remote sensing data. Using object-oriented technology, this method overcomes the operational limitations of traditional relational databases. To demonstrate the speed and efficiency of time-centric analysis using the Data Rods model, we have developed a sea ice detection algorithm. This application determines the concentration of sea ice in a small spatial region across a long temporal window. If performed using traditional analytical techniques, this task would typically require extensive data downloads and spatial filtering. Using Data Rods databases, the exact spatio-temporal data set is immediately available No extraneous data is downloaded, and all selected data querying occurs transparently on the server side. Moreover, fundamental statistical

  9. Non-destructive thermal wave method applied to study thermal properties of fast setting time endodontic cement

    NASA Astrophysics Data System (ADS)

    Picolloto, A. M.; Mariucci, V. V. G.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Astrath, N. G. C.; Astrath, F. B. G.; Santos, A. D.; Moraes, J. C. S.; Bento, A. C.

    2013-11-01

    The thermal wave method is applied for thermal properties measurement in fast endodontic cement (CER). This new formula is developed upon using Portland cement in gel and it was successfully tested in mice with good biocompatibility and stimulated mineralization. Recently, thermal expansion and setting time were measured, conferring to this material twice faster hardening than the well known Angelus Mineral trioxide aggregate (MTA) the feature of fast hardening (˜7 min) and with similar thermal expansion (˜12 μstrain/ °C). Therefore, it is important the knowledge of thermal properties like thermal diffusivity, conductivity, effusivity in order to match thermally the tissue environment upon its application in filling cavities of teeth. Photothermal radiometry technique based on Xe illumination was applied in CER disks 600 μm thick for heating, with prepared in four particle sizes (25, 38, 45, and 53) μm, which were added microemulsion gel with variation volumes (140, 150, 160, and 170) μl. The behavior of the thermal diffusivity CER disks shows linear decay for increase emulsion volume, and in contrast, thermal diffusivity increases with particles sizes. Aiming to compare to MTA, thermal properties of CER were averaged to get the figure of merit for thermal diffusivity as (44.2 ± 3.6) × 10-3 cm2/s, for thermal conductivity (228 ± 32) mW/cm K, the thermal effusivity (1.09 ± 0.06) W s0.5/cm2 K and volume heat capacity (5.2 ± 0.7) J/cm3 K, which are in excellent agreement with results of a disk prepared from commercial MTA-Angelus (grain size < 10 μm using 57 μl of distilled water).

  10. Non-destructive thermal wave method applied to study thermal properties of fast setting time endodontic cement

    SciTech Connect

    Picolloto, A. M.; Mariucci, V. V. G.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Astrath, N. G. C.; Astrath, F. B. G.; Bento, A. C.; Santos, A. D.; Moraes, J. C. S.

    2013-11-21

    The thermal wave method is applied for thermal properties measurement in fast endodontic cement (CER). This new formula is developed upon using Portland cement in gel and it was successfully tested in mice with good biocompatibility and stimulated mineralization. Recently, thermal expansion and setting time were measured, conferring to this material twice faster hardening than the well known Angelus Mineral trioxide aggregate (MTA) the feature of fast hardening (∼7 min) and with similar thermal expansion (∼12 μstrain/ °C). Therefore, it is important the knowledge of thermal properties like thermal diffusivity, conductivity, effusivity in order to match thermally the tissue environment upon its application in filling cavities of teeth. Photothermal radiometry technique based on Xe illumination was applied in CER disks 600 μm thick for heating, with prepared in four particle sizes (25, 38, 45, and 53) μm, which were added microemulsion gel with variation volumes (140, 150, 160, and 170) μl. The behavior of the thermal diffusivity CER disks shows linear decay for increase emulsion volume, and in contrast, thermal diffusivity increases with particles sizes. Aiming to compare to MTA, thermal properties of CER were averaged to get the figure of merit for thermal diffusivity as (44.2 ± 3.6) × 10{sup −3} cm{sup 2}/s, for thermal conductivity (228 ± 32) mW/cm K, the thermal effusivity (1.09 ± 0.06) W s{sup 0.5}/cm{sup 2} K and volume heat capacity (5.2 ± 0.7) J/cm{sup 3} K, which are in excellent agreement with results of a disk prepared from commercial MTA-Angelus (grain size < 10 μm using 57 μl of distilled water)

  11. Trauma exposure, posttraumatic stress disorder and depression in an African-American primary care population.

    PubMed Central

    Alim, Tanya N.; Graves, Elaine; Mellman, Thomas A.; Aigbogun, Notalelomwan; Gray, Ekwenzi; Lawson, William; Charney, Dennis S.

    2006-01-01

    OBJECTIVE: Trauma exposure is high in African Americans who live in stressful urban environments. Posttraumatic stress disorder (PTSD) and depression are common outcomes of trauma exposure and are understudied in African Americans. African Americans are more likely to seek treatment for psychiatric disorders in a primary care setting. Our study evaluated trauma exposure, PTSD and major depression in African Americans attending primary care offices. METHOD: Six-hundred-seventeen patients (96% African Americans) were surveyed for trauma exposure in the waiting rooms of four primary care offices. Those patients reporting significant traumatic events were invited to a research interview. Of the 403 patients with trauma exposure, 279 participated. RESULTS: Of the 617 participants, 65% reported > or = 1 clearly traumatic event. The most common exposures were transportation accidents (42%), sudden unexpected death of a loved one (39%), physical assault (30%), assault with a weapon (29%) and sexual assault (25%). Lifetime prevalence of PTSD and a major depressive episode (MDE) among those with trauma exposure (n=279) was 51% and 35%, respectively. The percent of lifetime PTSD cases (n=142) with comorbid MDE was 46%. Lifetime PTSD and MDE in the trauma-exposed population were approximately twice as common in females than males, whereas current PTSD rates were similar. CONCLUSIONS: Our rate of PTSD (approximately 33% of those screened) exceeds estimates for the general population. Rates of MDE comorbid with PTSD were comparable to other studies. These findings suggest the importance of screening African Americans for PTSD, in addition to depression, in the primary care setting. PMID:17052054

  12. Characterization of full set material constants of piezoelectric materials based on ultrasonic method and inverse impedance spectroscopy using only one sample.

    PubMed

    Li, Shiyang; Zheng, Limei; Jiang, Wenhua; Sahul, Raffi; Gopalan, Venkatraman; Cao, Wenwu

    2013-09-14

    The most difficult task in the characterization of complete set material properties for piezoelectric materials is self-consistency. Because there are many independent elastic, dielectric, and piezoelectric constants, several samples are needed to obtain the full set constants. Property variation from sample to sample often makes the obtained data set lack of self-consistency. Here, we present a method, based on pulse-echo ultrasound and inverse impedance spectroscopy, to precisely determine the full set physical properties of piezoelectric materials using only one small sample, which eliminated the sample to sample variation problem to guarantee self-consistency. The method has been applied to characterize the [001]C poled Mn modified 0.27Pb(In1/2Nb1/2)O3-0.46Pb(Mg1/3Nb2/3)O3-0.27PbTiO3 single crystal and the validity of the measured data is confirmed by a previously established method. For the inverse calculations using impedance spectrum, the stability of reconstructed results is analyzed by fluctuation analysis of input data. In contrast to conventional regression methods, our method here takes the full advantage of both ultrasonic and inverse impedance spectroscopy methods to extract all constants from only one small sample. The method provides a powerful tool for assisting novel piezoelectric materials of small size and for generating needed input data sets for device designs using finite element simulations.

  13. 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.

  14. Dry deposition of nitrogen compounds (NO2, HNO3, NH3), sulfur dioxide and ozone in west and central African ecosystems using the inferential method

    NASA Astrophysics Data System (ADS)

    Adon, M.; Galy-Lacaux, C.; Delon, C.; Yoboue, V.; Solmon, F.; Kaptue Tchuente, A. T.

    2013-11-01

    This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long-term monitoring of gas concentrations (1998-2007) established at seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on the one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2 and O3) and on the other hand modeled exchange rates. Dry deposition velocities (Vd) were calculated using the big-leaf model of Zhang et al. (2003b). The bidirectional approach is used for NH3 surface-atmosphere exchange (Zhang et al., 2010). Surface and meteorological conditions specific to IDAF sites have been used in the models of deposition. The seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3 and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from -0.4 to -0.8 kg N ha-1 yr-1 for NO2, from -0.7 to -1.0 kg N ha-1 yr-1 for HNO3 and from -0.7 to -8.3 kg N ha-1 yr-1 for NH3 over the study period (1998-2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (-10 kg N ha-1 yr-1) than in wet and dry savannas (-1.6 to -3.9 kg N ha-1 yr-1). The annual mean dry deposition fluxes of ozone range between -11 and -19 kg ha-1 yr-1 in dry and wet savannas, and -11 and -13 kg ha-1 yr-1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower by a factor of 2-3, compared to other ecosystems. Along the ecosystem transect, the annual mean of SO2 dry deposition fluxes presents low values and a small variability (-0.5 to -1 kg S ha-1 yr-1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period.

  15. The Epworth Score in African American Populations

    PubMed Central

    Hayes, Amanda L.; Spilsbury, James C.; Patel, Sanjay R.

    2009-01-01

    Introduction: African Americans have elevated scores on the Epworth Sleepiness Scale (ESS) compared to whites. The reason for this difference is not clear. Methods: Responses to the ESS were assessed in 687 patients (52.3% African American) referred to a hospital-based sleep clinic. Differences in total ESS score and the scores on individual Epworth questions were compared in African Americans and whites. Findings were validated in an independent sleep apnea research cohort of 712 subjects (57.3% African Americans). Results: African Americans in the clinic-based population had a higher mean ESS score than whites (11.4 ± 0.3 vs. 9.8 ± 0.3, p < 0.0001). This difference persisted after adjusting for sleepiness risk factors. In adjusted analyses including responses to the other ESS questions, African Americans scored significantly greater on 3 of the 8 ESS component questions: questions 2-“Watching TV,” 6-“Sitting and talking to someone,” and 7-“Sitting quietly after lunch without alcohol.” In the validation cohort, African Americans also had a higher mean ESS score (9.1 ± 0.3, vs. 8.2 ± 0.3, p = 0.04). In addition they had significantly elevated scores on questions 6 and 7 (p = 0.0002, p = 0.012 respectively) even after adjusting for responses to the other Epworth questions. Conclusions: African Americans have greater sleepiness than whites as assessed by the ESS; this is independent of sleepiness risk factors. The difference appears due primarily to differences in responses to questions 6 and 7 of the ESS questions suggesting a difference in the interpretation of these 2 questions. Citation: Hayes AL; Spilsbury JC; Patel SR. The Epworth score in African American populations. J Clin Sleep Med 2009;5(4):344-348. PMID:19968012

  16. Choosing healthier foods in recreational sports settings: a mixed methods investigation of the impact of nudging and an economic incentive

    PubMed Central

    2014-01-01

    Background Nudging is an approach to environmental change that alters social and physical environments to shift behaviors in positive, self-interested directions. Evidence indicates that eating is largely an automatic behavior governed by environmental cues, suggesting that it might be possible to nudge healthier dietary behaviors. This study assessed the comparative and additive efficacy of two nudges and an economic incentive in supporting healthy food purchases by patrons at a recreational swimming pool. Methods An initial pre-intervention period was followed by three successive and additive interventions that promoted sales of healthy items through: signage, taste testing, and 30% price reductions; concluding with a return to baseline conditions. Each period was 8 days in length. The primary outcome was the change in the proportion of healthy items sold in the intervention periods relative to pre- and post-intervention in the full sample, and in a subsample of patrons whose purchases were directly observed. Secondary outcomes included change in the caloric value of purchases, change in revenues and gross profits, and qualitative process observations. Data were analyzed using analysis of covariance, chi-square tests and thematic content analysis. Results Healthy items represented 41% of sales and were significantly lower than sales of unhealthy items (p < 0.0001). In the full sample, sales of healthy items did not differ across periods, whereas in the subsample, sales of healthy items increased by 30% when a signage + taste testing intervention was implemented (p < 0.01). This increase was maintained when prices of healthy items were reduced by 30%, and when all interventions were removed. When adults were alone they purchased more healthy items compared to when children were present during food purchases (p < 0.001), however parental choices were not substantially better than choices made by children alone. Conclusions This study found mixed

  17. Production of a long-term global water vapor and liquid water data set using ultra-fast methods to assimilate multi-satellite and radiosonde observations

    NASA Technical Reports Server (NTRS)

    Vonderhaar, Thomas H.; Randel, David L.; Reinke, Donald L.; Stephens, Graeme L.; Ringerud, Mark A.; Combs, Cynthia L.; Greenwald, Thomas J.; Wittmeyer, Ian L.

    1995-01-01

    There is a well-documented requirement for a comprehensive and accurate global moisture data set to assist many important studies in atmospheric science. Currently, atmospheric water vapor measurements are made from a variety of sources including radiosondes, aircraft and surface observations, and in recent years, by various satellite instruments. Creating a global data set from a single measuring system produces results that are useful and accurate only in specific situations and/or areas. Therefore, an accurate global moisture data set has been derived from a combination of these measurement systems. Under a NASA peer-reviewed contract, STC-METSAT produced two 5-yr (1988-1992) global data sets. One is the total column (integrated) water vapor data set and the other, a global layered water vapor data set using a combination of radiosonde observations, Television and Infrared Observation Satellite (TIROS) Operational Satellite (TOVS), and Special Sensor Microwave/Imager (SSM/I) data sets. STC-METSAT also produced a companion, global, integrated liquid water data set. The complete data set (all three products) has been named NVAP, an anachronym for NASA Water Vapor Project. STC-METSAT developed methods to process the data at a daily time scale and 1 x 1 deg spatial resolution.

  18. The African Mythology: Old and New.

    ERIC Educational Resources Information Center

    Murphy, E. Jefferson

    Myths about Africa are an inevitable outgrowth of a fundamental set of cultural assumptions about race and civilization that have been building in Western culture for at least four hundred years. The old African mythology, which consisted of crude, uncomplimentary stereotypes has been replaced by a new mythology which is much more insidious and…

  19. Intertextuality in EAP: An African Context

    ERIC Educational Resources Information Center

    Holmes, John

    2004-01-01

    This paper focuses on the development of EAP methodology within an African EAP context. I describe the setting up and implementation of an EAP study skills programme at the University of Asmara, Eritrea, over the period 1994-1998 and its subsequent development up to 2002. The unique social and political context of the EAP programme served as a…

  20. City Children in African Children's Literature.

    ERIC Educational Resources Information Center

    Kuntz, Patricia S.

    A descriptive study identified titles and features of children's books set in an African city. Data were collected from various reviews of children's literature for titles published since 1980. In addition, the Cooperative Children's Book Center's log list of acquired titles for Africa from 1990 to 1996 was reviewed. Results showed that authors…