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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. Impact of Goal Setting and Goal Attainment Methods on Asthma Outcomes: Findings From an Asthma Self-Management Intervention for African American Women

    ERIC Educational Resources Information Center

    Aaron, Micah; Nelson, Belinda W.; Kaltsas, Elena; Brown, Randall W.; Thomas, Lara J.; Patel, Minal R.

    2017-01-01

    Optimal use of goal-setting strategies in self-management efforts with high-risk individuals with asthma is not well understood. This study aimed to describe factors associated with goal attainment in an asthma self-management intervention for African American women with asthma and determine whether goal attainment methods proved beneficial to…

  3. Combination vaccines in the South African setting.

    PubMed

    Visser, Adele; Hoosen, Anwar

    2012-09-07

    The number of vaccines available and included as part of the national immunization schedules, has increased significantly over the past few decades. This impacts on patient/parent compliance and creates a challenge for health care providers for implementation of schedules necessitating training and infrastructure improvements. Use of combination rather than component vaccines offers advantages for compliance by single dose administration of various antigens, reducing stock costing as well as reducing cost of additional health care visits. Combination vaccines are often significantly more expensive than individual constituent vaccines. Concerns regarding an increased incidence of adverse events with use of combination vaccines have not been confirmed and rates may seem high as the adverse events seem to mimic the sum total of adverse event rates for each individual antigen used but may in fact be lower. Manufacturers typically advise against interchanging use of vaccine products. Despite this, health authorities advocate use of an alternative vaccine where the original vaccine in not available, to ensure continuity of vaccination. A notable exception is the acellular pertussis vaccine. Partly, because no serological correlates of immunity exist, but also a general lack of convincing follow up studies has prompted the recommendation for manufacturer fidelity for at least the first 3 vaccine doses. According to the South African Medicines Formulary, a variety of vaccines are available in South Africa. Although a large number are available in the private sector, the only true combination vaccine included in the current state EPI, modified in 2009, is the DTaP-IPV/Hib vaccine (Diphtheria, Tetanus, acellular Pertussis, inactivated Poliomyelitis virus and Haemophilus influenzae type b). There are many reasons justifying the use of combination vaccines rather that the individual constituent formulations. Implementation of use in the South African setting at this point is

  4. Multicriteria identification sets method

    NASA Astrophysics Data System (ADS)

    Kamenev, G. K.

    2016-11-01

    A multicriteria identification and prediction method for mathematical models of simulation type in the case of several identification criteria (error functions) is proposed. The necessity of the multicriteria formulation arises, for example, when one needs to take into account errors of completely different origins (not reducible to a single characteristic) or when there is no information on the class of noise in the data to be analyzed. An identification sets method is described based on the approximation and visualization of the multidimensional graph of the identification error function and sets of suboptimal parameters. This method allows for additional advantages of the multicriteria approach, namely, the construction and visual analysis of the frontier and the effective identification set (frontier and the Pareto set for identification criteria), various representations of the sets of Pareto effective and subeffective parameter combinations, and the corresponding predictive trajectory tubes. The approximation is based on the deep holes method, which yields metric ɛ-coverings with nearly optimal properties, and on multiphase approximation methods for the Edgeworth-Pareto hull. The visualization relies on the approach of interactive decision maps. With the use of the multicriteria method, multiple-choice solutions of identification and prediction problems can be produced and justified by analyzing the stability of the optimal solution not only with respect to the parameters (robustness with respect to data) but also with respect to the chosen set of identification criteria (robustness with respect to the given collection of functionals).

  5. Challenges in reducing group B Streptococcus disease in African settings

    PubMed Central

    Nishihara, Yo; Dangor, Ziyaad; French, Neil; Madhi, Shabir; Heyderman, Robert

    2017-01-01

    Group B Streptococcus (GBS) is a leading cause of neonatal sepsis and meningitis in high-income settings and is associated with high rates of neonatal mortality and morbidity. There is now increasing evidence to suggest that there is a high GBS disease burden in resource-limited countries, and it is therefore critically important to identify suitable and practical preventive strategies. In Europe and North America, intrapartum antibiotic prophylaxis (IAP) has led to a dramatic reduction of early-onset GBS disease. However, the methods for identifying pregnant women who should receive IAP and how to reduce late-onset GBS disease are not without controversy and are challenging for most sub-Saharan African countries. GBS vaccines are approaching phase III trials but are still under development. This review aims to explore the current evidence related to strategies for reducing invasive GBS disease in an African setting, the development of a GBS vaccine and whether preventative measures against GBS disease can be practically implemented. PMID:27831912

  6. 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

  7. Assessment of an undergraduate psychiatry course in an African setting

    PubMed Central

    Baig, Benjamin J; Beaglehole, Anna; Stewart, Robert C; Boeing, Leonie; Blackwood, Douglas H; Leuvennink, Johan; Kauye, Felix

    2008-01-01

    Background International reports recommend the improvement in the amount and quality of training for mental health workers in low and middle income countries. The Scotland-Malawi Mental Health Education Project (SMMHEP) has been established to support the teaching of psychiatry to medical students in the University of Malawi. While anecdotally supportive medical educational initiatives appear of value, little quantitative evidence exists to demonstrate whether such initiatives can deliver comparable educational standards. This study aimed to assess the effectiveness of an undergraduate psychiatry course given by UK psychiatrists in Malawi by studying University of Malawi and Edinburgh University medical students' performance on an MCQ examination paper. Methods An undergraduate psychiatry course followed by an MCQ exam was delivered by the SMMHEP to 57 Malawi medical students. This same MCQ exam was given to 71 Edinburgh University medical students who subsequently sat their own Edinburgh University examination. Results There were no significant differences between Edinburgh students' performance on the Malawi exam and their own Edinburgh University exam. (p = 0.65). This would suggest that the Malawi exam is a comparable standard to the Edinburgh exam. Malawi students marks ranged from 52.4%–84.6%. Importantly 84.4% of Malawi students scored above 60% on their exam which would equate to a hypothetical pass by UK university standards. Conclusion The support of an undergraduate course in an African setting by high income country specialists can attain a high percentage pass rate by UK standards. Although didactic teaching has been surpassed by more novel educational methods, in resource poor countries it remains an effective and cost effective method of gaining an important educational standard. PMID:18430237

  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, Roger Brent

    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. 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 literacy…

  11. Beauty salons: a promising health promotion setting for reaching and promoting health among African American women.

    PubMed

    Linnan, Laura A; Ferguson, Yvonne Owens

    2007-06-01

    African American women suffer disproportionately from a wide range of health disparities. This article clarifies how beauty salons can be mobilized at all levels of the social-ecological framework to address disparities in health among African American women. The North Carolina BEAUTY and Health Project is a randomized, controlled intervention trial that takes into account the unique and multilevel features of the beauty salon setting with interventions that address owners, customers, stylists; interactions between customers and stylists; and the salon environment. The authors make explicit the role of the political economy of health theoretical perspective for understanding important factors (social, political, historical, and economic) that should be considered if the goal is to create successful, beauty-salon-based interventions. Despite some important challenges, the authors contend that beauty salons represent a promising setting for maximizing reach, reinforcement, and the impact of public health interventions aimed at addressing health disparities among African American women.

  12. Advancing understanding of the sustainability of lay health advisor (LHA) programs for African-American women in community settings.

    PubMed

    Shelton, Rachel C; Charles, Thana-Ashley; Dunston, Sheba King; Jandorf, Lina; Erwin, Deborah O

    2017-03-23

    Lay health advisor (LHA) programs have made strong contributions towards the elimination of health disparities and are increasingly being implemented to promote health and prevent disease. Developed in collaboration with African-American survivors, the National Witness Project (NWP) is an evidence-based, community-led LHA program that improves cancer screening among African-American women. NWP has been successfully disseminated, replicated, and implemented nationally in over 40 sites in 22 states in diverse community settings, reaching over 15,000 women annually. We sought to advance understanding of barriers and facilitators to the long-term implementation and sustainability of LHA programs in community settings from the viewpoint of the LHAs, as well as the broader impact of the program on African-American communities and LHAs. In the context of a mixed-methods study, in-depth telephone interviews were conducted among 76 African-American LHAs at eight NWP sites at baseline and 12-18 months later, between 2010 and 2013. Qualitative data provides insight into inner and outer contextual factors (e.g., community partnerships, site leadership, funding), implementation processes (e.g., training), as well as characteristics of the intervention (e.g., perceived need and fit in African-American community) and LHAs (e.g., motivations, burnout) that are perceived to impact the continued implementation and sustainability of NWP. Factors at the contextual levels and related to motivations of LHAs are critical to the sustainability of LHA programs. We discuss how findings are used to inform (1) the development of the LHA Sustainability Framework and (2) strategies to support the continued implementation and sustainability of evidence-based LHA interventions in community settings.

  13. Leading School Improvement: African American Women Principals in Urban Educational Settings

    ERIC Educational Resources Information Center

    Mack, Yejide S.

    2010-01-01

    African American women administrators working in urban educational settings have been found to be effective leaders of school improvement. Underutilized women and people of color are the untapped value that organizations of all types need to enhance creativity, change efforts, teamwork, and financial benefits (Northouse, 2001). During the last…

  14. Willingness to Know the Cause of Death and Hypothetical Acceptability of the Minimally Invasive Autopsy in Six Diverse African and Asian Settings: A Mixed Methods Socio-Behavioural Study

    PubMed Central

    Maixenchs, Maria; Anselmo, Rui; Zielinski-Gutiérrez, Emily; Odhiambo, Frank O.; Akello, Clarah; Zaidi, S. Shujaat H.; Soofi, Sajid Bashir; Bhutta, Zulfiqar A.; Diarra, Kounandji; Djitèye, Mahamane; Dembélé, Roukiatou; Sow, Samba; Minsoko, Pamela Cathérine Angoissa; Agnandji, Selidji Todagbe; Ismail, Mamudo R.; Carrilho, Carla; Ordi, Jaume; Menéndez, Clara; Bassat, Quique

    2016-01-01

    Background The minimally invasive autopsy (MIA) is being investigated as an alternative to complete diagnostic autopsies for cause of death (CoD) investigation. Before potential implementation of the MIA in settings where post-mortem procedures are unusual, a thorough assessment of its feasibility and acceptability is essential. Methods and Findings We conducted a socio-behavioural study at the community level to understand local attitudes and perceptions related to death and the hypothetical feasibility and acceptability of conducting MIAs in six distinct settings in Gabon, Kenya, Mali, Mozambique, and Pakistan. A total of 504 interviews (135 key informants, 175 health providers [including formal health professionals and traditional or informal health providers], and 194 relatives of deceased people) were conducted. The constructs “willingness to know the CoD” and “hypothetical acceptability of MIAs” were quantified and analysed using the framework analysis approach to compare the occurrence of themes related to acceptability across participants. Overall, 75% (379/504) of the participants would be willing to know the CoD of a relative. The overall hypothetical acceptability of MIA on a relative was 73% (366/504). The idea of the MIA was acceptable because of its perceived simplicity and rapidity and particularly for not “mutilating” the body. Further, MIAs were believed to help prevent infectious diseases, address hereditary diseases, clarify the CoD, and avoid witchcraft accusations and conflicts within families. The main concerns regarding the procedure included the potential breach of confidentiality on the CoD, the misperception of organ removal, and the incompatibility with some religious beliefs. Formal health professionals were concerned about possible contradictions between the MIA findings and the clinical pre-mortem diagnoses. Acceptability of the MIA was equally high among Christian and Islamic communities. However, in the two predominantly

  15. A variant reference data set for the Africanized honeybee, Apis mellifera

    PubMed Central

    Kadri, Samir M.; Harpur, Brock A.; Orsi, Ricardo O.; Zayed, Amro

    2016-01-01

    The Africanized honeybee (AHB) is a population of Apis mellifera found in the Americas. AHBs originated in 1956 in Rio Clara, Brazil where imported African A. m. scutellata escaped and hybridized with local populations of European A. mellifera. Africanized populations can now be found from Northern Argentina to the Southern United States. AHBs—often referred to as ‘Killer Bees’— are a major concern to the beekeeping industry as well as a model for the evolutionary genetics of colony defence. We performed high coverage pooled-resequencing of 360 diploid workers from 30 Brazilian AHB colonies using Illumina Hi-Seq (150 bp PE). This yielded a high density SNP data set with an average read depth at each site of 20.25 reads. With 3,606,720 SNPs and 155,336 SNPs within 11,365 genes, this data set is the largest genomic resource available for AHBs and will enable high-resolution studies of the population dynamics, evolution, and genetics of this successful biological invader, in addition to facilitating the development of SNP-based tools for identifying AHBs. PMID:27824336

  16. A variant reference data set for the Africanized honeybee, Apis mellifera.

    PubMed

    Kadri, Samir M; Harpur, Brock A; Orsi, Ricardo O; Zayed, Amro

    2016-11-08

    The Africanized honeybee (AHB) is a population of Apis mellifera found in the Americas. AHBs originated in 1956 in Rio Clara, Brazil where imported African A. m. scutellata escaped and hybridized with local populations of European A. mellifera. Africanized populations can now be found from Northern Argentina to the Southern United States. AHBs-often referred to as 'Killer Bees'- are a major concern to the beekeeping industry as well as a model for the evolutionary genetics of colony defence. We performed high coverage pooled-resequencing of 360 diploid workers from 30 Brazilian AHB colonies using Illumina Hi-Seq (150 bp PE). This yielded a high density SNP data set with an average read depth at each site of 20.25 reads. With 3,606,720 SNPs and 155,336 SNPs within 11,365 genes, this data set is the largest genomic resource available for AHBs and will enable high-resolution studies of the population dynamics, evolution, and genetics of this successful biological invader, in addition to facilitating the development of SNP-based tools for identifying AHBs.

  17. A Lagrangian particle level set method

    NASA Astrophysics Data System (ADS)

    Hieber, Simone E.; Koumoutsakos, Petros

    2005-11-01

    We present a novel particle level set method for capturing interfaces. The level set equation is solved in a Lagrangian frame using particles that carry the level set information. A key aspect of the method involves a consistent remeshing procedure for the regularization of the particle locations when the particle map gets distorted by the advection field. The Lagrangian description of the level set method is inherently adaptive and exact in the case of solid body motions. The efficiency and accuracy of the method is demonstrated in several benchmark problems in two and three dimensions involving pure advection and curvature induced motion of the interface. The simplicity of the particle description is shown to be well suited for real time simulations of surfaces involving cutting and reconnection as in virtual surgery environments.

  18. 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…

  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. 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

  1. 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.

  2. 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

  3. 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.

  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. Iris segmentation using variational level set method

    NASA Astrophysics Data System (ADS)

    Roy, Kaushik; Bhattacharya, Prabir; Suen, Ching Y.

    2011-04-01

    Continuous efforts have been made to process degraded iris images for enhancement of the iris recognition performance in unconstrained situations. Recently, many researchers have focused on developing the iris segmentation techniques, which can deal with iris images in a non-cooperative environment where the probability of acquiring unideal iris images is very high due to gaze deviation, noise, blurring, and occlusion by eyelashes, eyelids, glasses, and hair. Although there have been many iris segmentation methods, most focus primarily on the accurate detection of iris images captured in a closely controlled environment. The novelty of this research effort is that we propose to apply a variational level set-based curve evolution scheme that uses a significantly larger time step to numerically solve the evolution partial differential equation (PDE) for segmentation of an unideal iris image accurately, and thereby, speeding up the curve evolution process drastically. The iris boundary represented by the variational level set may break and merge naturally during evolution, and thus, the topological changes are handled automatically. The proposed variational model is also robust against poor localization and weak iris/sclera boundaries. In order to solve the size irregularities occurring due to arbitrary shapes of the extracted iris/pupil regions, a simple method is applied based on connection of adjacent contour points. Furthermore, to reduce the noise effect, we apply a pixel-wise adaptive 2D Wiener filter. The verification and identification performance of the proposed scheme is validated on three challenging iris image datasets, namely, the ICE 2005, the WVU Unideal, and the UBIRIS Version 1.

  6. 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.

  7. 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

  8. 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…

  9. 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…

  10. Selecting renal replacement therapies: what do African American and non-African American patients and their families think others should know? A mixed methods study

    PubMed Central

    2013-01-01

    Background Little is known regarding the types of information African American and non-African American patients with chronic kidney disease (CKD) and their families need to inform renal replacement therapy (RRT) decisions. Methods In 20 structured group interviews, we elicited views of African American and non-African American patients with CKD and their families about factors that should be addressed in educational materials informing patients’ RRT selection decisions. We asked participants to select factors from a list and obtained their open-ended feedback. Results Ten groups of patients (5 African American, 5 non-African American; total 68 individuals) and ten groups of family members (5 African American, 5 non-African American; total 62 individuals) participated. Patients and families had a range (none to extensive) of experiences with various RRTs. Patients identified morbidity or mortality, autonomy, treatment delivery, and symptoms as important factors to address. Family members identified similar factors but also cited the effects of RRT decisions on patients’ psychological well-being and finances. Views of African American and non-African American participants were largely similar. Conclusions Educational resources addressing the influence of RRT selection on patients’ morbidity and mortality, autonomy, treatment delivery, and symptoms could help patients and their families select RRT options closely aligned with their values. Including information about the influence of RRT selection on patients’ personal relationships and finances could enhance resources’ cultural relevance for African Americans. PMID:23317336

  11. Intimate partner violence and HIV risk factors among African American and African Caribbean women in clinic-based settings

    PubMed Central

    Stockman, Jamila K.; Lucea, Marguerite B.; Draughon, Jessica E.; Sabri, Bushra; Anderson, Jocelyn C.; Bertrand, Desiree; Campbell, Doris W.; Callwood, Gloria B.; Campbell, Jacquelyn C.

    2012-01-01

    Despite progress against intimate partner violence (IPV) and HIV/AIDS in the past two decades, both epidemics remain major public health problems, particularly among women of color. The objective of this study was to assess the relationship between recent IPV and HIV risk factors (sexual and drug risk behaviors, STIs, condom use and negotiation) among women of African descent. We conducted a comparative case-control study in women’s health clinics in Baltimore, Maryland and St. Thomas and St. Croix, US Virgin Islands (USVI). Women aged 18–55 years who experienced physical and/or sexual IPV in the past two years (Baltimore, n=107; USVI, n=235) were compared to women who never experienced any form of abuse (Baltimore, n=207; USVI, n=119). Logistic regression identified correlates of recent IPV by site. In both sites, having a partner with concurrent sex partners was independently associated with a history of recent IPV (Baltimore, AOR: 3.91, 95% CI:1.79–8.55 and USVI, AOR: 2.25, 95% CI:1.11–4.56). In Baltimore, factors independently associated with recent IPV were lifetime casual sex partners (AOR: 1.99, 95% CI: 1.11–3.57), exchange sex partners (AOR: 5.26, 95% CI:1.92–14.42), infrequent condom use during vaginal sex (AOR: 0.24, 95% CI:0.08–0.72), and infrequent condom use during anal sex (AOR: 0.29, 95% CI:0.09–0.93). In contrast, in the USVI, having a concurrent sex partner (AOR: 3.33, 95% CI:1.46–7.60), frequent condom use during vaginal sex (AOR: 1.97, 95% CI:1.06–3.65), frequent condom use during anal sex (AOR: 6.29, 95% CI:1.57–25.23), drug use (AOR: 3.16, 95% CI:1.00–10.06), and a past-year STI (AOR: 2.68, 95% CI:1.25–5.72) were associated with recent IPV history. The divergent results by site warrant further investigation into the potential influence of culture, norms, and intentions on the relationships examined. Nonetheless, study findings support a critical need to continue the development and implementation of culturally tailored

  12. 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…

  13. Feasibility and acceptability of ACT for the community case management of malaria in urban settings in five African sites

    PubMed Central

    2011-01-01

    Background The community case management of malaria (CCMm) is now an established route for distribution of artemisinin-based combination therapy (ACT) in rural areas, but the feasibility and acceptability of the approach through community medicine distributors (CMD) in urban areas has not been explored. It is estimated that in 15 years time 50% of the African population will live in urban areas and transmission of the malaria parasite occurs in these densely populated areas. Methods Pre- and post-implementation studies were conducted in five African cities: Ghana, Burkina Faso, Ethiopia and Malawi. CMDs were trained to educate caregivers, diagnose and treat malaria cases in < 5-year olds with ACT. Household surveys, focus group discussions and in-depth interviews were used to evaluate impact. Results Qualitative findings: In all sites, interviews revealed that caregivers' knowledge of malaria signs and symptoms improved after the intervention. Preference for CMDs as preferred providers for malaria increased in all sites. Quantitative findings: 9001 children with an episode of fever were treated by 199 CMDs in the five study sites. Results from the CHWs registers show that of these, 6974 were treated with an ACT and 6933 (99%) were prescribed the correct dose for their age. Fifty-four percent of the 3,025 children for which information about the promptness of treatment was available were treated within 24 hours from the onset of symptoms. From the household survey 3700 children were identified who had an episode of fever during the preceding two weeks. 1480 (40%) of them sought treatment from a CMD and 1213 of them (82%) had received an ACT. Of these, 1123 (92.6%) were administered the ACT for the correct number of doses and days; 773 of the 1118 (69.1%) children for which information about the promptness of treatment was available were treated within 24 hours from onset of symptoms, and 768 (68.7%) were treated promptly and correctly. Conclusions The concept of

  14. Variants of the protein PRDM9 differentially regulate a set of human meiotic recombination hotspots highly active in African populations.

    PubMed

    Berg, Ingrid L; Neumann, Rita; Sarbajna, Shriparna; Odenthal-Hesse, Linda; Butler, Nicola J; Jeffreys, Alec J

    2011-07-26

    PRDM9 is a major specifier of human meiotic recombination hotspots, probably via binding of its zinc-finger repeat array to a DNA sequence motif associated with hotspots. However, our view of PRDM9 regulation, in terms of motifs defined and hotspots studied, has a strong bias toward the PRDM9 A variant particularly common in Europeans. We show that population diversity can reveal a second class of hotspots specifically activated by PRDM9 variants common in Africans but rare in Europeans. These African-enhanced hotspots nevertheless share very similar properties with their counterparts activated by the A variant. The specificity of hotspot activation is such that individuals with differing PRDM9 genotypes, even within the same population, can use substantially if not completely different sets of hotspots. Each African-enhanced hotspot is activated by a distinct spectrum of PRDM9 variants, despite the fact that all are predicted to bind the same sequence motif. This differential activation points to complex interactions between the zinc-finger array and hotspots and identifies features of the array that might be important in controlling hotspot activity.

  15. South African health financing reform 2000-2010: understanding the agenda-setting process.

    PubMed

    Pillay, Timesh D; Skordis-Worrall, Jolene

    2013-03-01

    Governments around the world are struggling to address persistent disparities in health care access. However, this priority competes with many others for support in moving onto and up the political agenda. In this paper, a novel method of agenda-setting analysis is developed by merging and modifying the Hall and Kingdon models. As a case study, this method is used to explore how health financing reform reached the policy agenda in South Africa between the years 2000 and 2010. Certain factors are identified that could have determined the agenda-setting process: a change in government, increase in the cost of private medical schemes, and increase in support for reform from various stakeholders. Further analysis, using a conceptual framework of interacting trends and shocks, identifies the growing middle class, the private sector, and workers unions as powerful actors and outlines further factors that may have contributed to the process: a broad political shift in the second half of the decade and the changing prioritisation of HIV/AIDS. Study findings have relevance to academics and policy makers in South Africa and beyond.

  16. 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

  17. 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.

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

    PubMed Central

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

    2014-01-01

    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 involving culturally relevant foods, stress reduction techniques, and communicating with racially/ethnically diverse physicians. We recruited participants from senior center members, area churches, and word of mouth. We conducted baseline and 4-month post-interviews. Results A total of 569 African American elders attended an introductory session, with 519 (91%) enrolling in the 6-session program. Of the 519, 444 (86%) completed ≥4 sessions and 414 (79%) completed pre–post interviews. We found small but statistically significant improvements for exercise (p = .001), use of cognitive management strategies (p = .001), energy/fatigue (p = .001), self-efficacy (p = .001), health distress (p = .001), and illness intrusiveness in different life domains (probabilities from .001–.021). We found no changes for health utilization. Outcomes did not differ by gender, number of sessions attended, number and type of chronic conditions, facilitator, leader, or recruitment site. Implications The CDSMP can be translated for delivery by trained senior center personnel to African American elders. Participant benefits compare favorably to original trial outcomes. The translated program is replicable and may help to address health disparities. PMID:18981286

  19. Differences Between Dual-Method and Non–Dual-Method Protection Use in a Sample of Young African American Women Residing in the Southeastern United States

    PubMed Central

    Sales, Jessica M.; Latham, Teaniese P.; DiClemente, Ralph J.; Rose, Eve

    2013-01-01

    Objectives To characterize dual-method protection users and report the prevalence of dual-method use among young adult African American women residing in the Southeastern United States. Design Analysis of baseline data from a randomized controlled trial. Setting A clinic-based sample of young women enrolled in a randomized trial of a human immunodeficiency virus (HIV)–prevention program in Atlanta, Georgia, from June 2005 to June 2007. Participants African American women aged 14 to 20 years who reported unprotected sexual activity in the past 6months. Of the eligible adolescents, 94% (N=701) were enrolled in the study and completed baseline assessments. Outcome Measures Dual-method protection use as well as sociodemographic, individual-level, interpersonal-level, and community-level factors and interpersonal communication skills. Only data from the baseline assessment, before randomization, were used for the analysis. Results A total of 102 participants (14.6%) were classified as dual-method protection users. After controlling for age and clinic, significant differences between dual-method users and non–dual-method users were found for impulsivity, self-esteem, social support, relationship style, partner communication self-efficacy, and fear of condom negotiation. Conclusions Dual-method protection use is low. Identification of factors that differentiate dual-method users from non–dual-method users at the individual, interpersonal, and community levels in this young African American sample suggests that HIV, sexually transmitted disease, and unintended pregnancy risk–reduction programs should address factors at each level, not simply the individual level, and that this may involve structural and/or clinical counseling practice changes in clinics that serve young women, to optimally facilitate dual-method protection use among young African American women in the Southeastern United States. PMID:21135341

  20. DISJUNCTIVE NORMAL LEVEL SET: AN EFFICIENT PARAMETRIC IMPLICIT METHOD

    PubMed Central

    Mesadi, Fitsum; Cetin, Mujdat; Tasdizen, Tolga

    2016-01-01

    Level set methods are widely used for image segmentation because of their capability to handle topological changes. In this paper, we propose a novel parametric level set method called Disjunctive Normal Level Set (DNLS), and apply it to both two phase (single object) and multiphase (multi-object) image segmentations. The DNLS is formed by union of polytopes which themselves are formed by intersections of half-spaces. The proposed level set framework has the following major advantages compared to other level set methods available in the literature. First, segmentation using DNLS converges much faster. Second, the DNLS level set function remains regular throughout its evolution. Third, the proposed multiphase version of the DNLS is less sensitive to initialization, and its computational cost and memory requirement remains almost constant as the number of objects to be simultaneously segmented grows. The experimental results show the potential of the proposed method.

  1. Identifying Heterogeneities in Subsurface Environment using the Level Set Method

    SciTech Connect

    Lei, Hongzhuan; Lu, Zhiming; Vesselinov, Velimir Valentinov

    2016-08-25

    These are slides from a presentation on identifying heterogeneities in subsurface environment using the level set method. The slides start with the motivation, then explain Level Set Method (LSM), the algorithms, some examples are given, and finally future work is explained.

  2. Chronology of the extant African elephant species and case study of the species identification of the small African elephant with the molecular phylogenetic method.

    PubMed

    Murata, Yumie; Yonezawa, Takahiro; Kihara, Ichiro; Kashiwamura, Toshihide; Sugihara, Yuji; Nikaido, Masato; Okada, Norihiro; Endo, Hideki; Hasegawa, Masami

    2009-07-15

    Despite vigorous genetic studies of African elephants (Loxodonta africana and L. cyclotis) during the last decade, their evolutionary history is still obscure. Phylogenetic studies and coalescence time estimation using longer nucleotide sequence data from denser samplings are necessary to better understand the natural history of African elephants. Further, species identification among African elephants is sometimes very difficult using only the external morphological characteristics. This is a serious problem for making an adequate breeding plan in zoological gardens. In this paper, we investigated the continent-wide phylogeographical pattern of the African elephants and estimated the coalescence times among them. From these molecular data and geological evidence, we proposed an evolutionary scenario for the African elephants. We further demonstrated the effectiveness of molecular phylogenetic methods in species identification.

  3. Adaptive Set-Based Methods for Association Testing.

    PubMed

    Su, Yu-Chen; Gauderman, William James; Berhane, Kiros; Lewinger, Juan Pablo

    2016-02-01

    With a typical sample size of a few thousand subjects, a single genome-wide association study (GWAS) using traditional one single nucleotide polymorphism (SNP)-at-a-time methods can only detect genetic variants conferring a sizable effect on disease risk. Set-based methods, which analyze sets of SNPs jointly, can detect variants with smaller effects acting within a gene, a pathway, or other biologically relevant sets. Although self-contained set-based methods (those that test sets of variants without regard to variants not in the set) are generally more powerful than competitive set-based approaches (those that rely on comparison of variants in the set of interest with variants not in the set), there is no consensus as to which self-contained methods are best. In particular, several self-contained set tests have been proposed to directly or indirectly "adapt" to the a priori unknown proportion and distribution of effects of the truly associated SNPs in the set, which is a major determinant of their power. A popular adaptive set-based test is the adaptive rank truncated product (ARTP), which seeks the set of SNPs that yields the best-combined evidence of association. We compared the standard ARTP, several ARTP variations we introduced, and other adaptive methods in a comprehensive simulation study to evaluate their performance. We used permutations to assess significance for all the methods and thus provide a level playing field for comparison. We found the standard ARTP test to have the highest power across our simulations followed closely by the global model of random effects (GMRE) and a least absolute shrinkage and selection operator (LASSO)-based test.

  4. Impact of Goal Setting and Goal Attainment Methods on Asthma Outcomes.

    PubMed

    Aaron, Micah; Nelson, Belinda W; Kaltsas, Elena; Brown, Randall W; Thomas, Lara J; Patel, Minal R

    2017-02-01

    Optimal use of goal-setting strategies in self-management efforts with high-risk individuals with asthma is not well understood. This study aimed to describe factors associated with goal attainment in an asthma self-management intervention for African American women with asthma and determine whether goal attainment methods proved beneficial to goal achievement and improved asthma outcomes. Data came from 212 African American women in the intervention arm of a randomized clinical trial evaluating a telephone-based asthma self-management program. Telephone interview data were collected to assess goals and goal attainment methods identified, asthma symptoms, asthma control, and asthma-related quality of life at baseline and 2-year follow-up. Generalized estimating equations were used to assess the long-term impact of goal setting and goal attainment methods on outcomes. The average age of the sample was 42.1 years ( SD = 14.8). Factors associated with goal attainment included higher education ( p < .01) and fewer depressive symptoms ( p < .01). Using a goal attainment method also resulted in more goals being achieved over the course of the intervention (Estimate [ SE] = 1.25 [0.18]; p < .001) when adjusted for clinical and demographic factors. Use of and types of goal attainment methods and goals were not found to significantly affect asthma control, quality of life, or frequency of nighttime asthma symptoms at follow-up. Using a method to achieve goals led to greater goal attainment. Goal attainment alone did not translate into improved asthma outcomes in our study sample. Further studies are warranted to assess the challenges of self-management in chronic disease patients with complex health needs and how goal setting and goal attainment methods can be strategically integrated into self-management efforts to improve health endpoints.

  5. Comparative Effectiveness of Standard versus Patient-Centered Collaborative Care Interventions for Depression among African Americans in Primary Care Settings: The BRIDGE Study

    PubMed Central

    Cooper, Lisa A; Ghods Dinoso, Bri K; Ford, Daniel E; Roter, Debra L; Primm, Annelle B; Larson, Susan M; Gill, James M; Noronha, Gary J; Shaya, Elias K; Wang, Nae-Yuh

    2013-01-01

    Objective To compare the effectiveness of standard and patient-centered, culturally tailored collaborative care (CC) interventions for African American patients with major depressive disorder (MDD) over 12 months of follow-up. Data Sources/Study Setting Twenty-seven primary care clinicians and 132 African American patients with MDD in urban community-based practices in Maryland and Delaware. Study Design Cluster randomized trial with patient-level, intent-to-treat analyses. Data Collection/Extraction Methods Patients completed screener and baseline, 6-, 12-, and 18-month interviews to assess depression severity, mental health functioning, health service utilization, and patient ratings of care. Principal Findings Patients in both interventions showed statistically significant improvements over 12 months. Compared with standard, patient-centered CC patients had similar reductions in depression symptom levels (−2.41 points; 95 percent confidence interval (CI), −7.7, 2.9), improvement in mental health functioning scores (+3.0 points; 95 percent CI, −2.2, 8.3), and odds of rating their clinician as participatory (OR, 1.48, 95 percent CI, 0.53, 4.17). Treatment rates increased among standard (OR = 1.8, 95 percent CI 1.0, 3.2), but not patient-centered (OR = 1.0, 95 percent CI 0.6, 1.8) CC patients. However, patient-centered CC patients rated their care manager as more helpful at identifying their concerns (OR, 3.00; 95 percent CI, 1.23, 7.30) and helping them adhere to treatment (OR, 2.60; 95 percent CI, 1.11, 6.08). Conclusions Patient-centered and standard CC approaches to depression care showed similar improvements in clinical outcomes for African Americans with depression; standard CC resulted in higher rates of treatment, and patient-centered CC resulted in better ratings of care. PMID:22716199

  6. 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…

  7. Status of pharmaceuticals in African water bodies: Occurrence, removal and analytical methods.

    PubMed

    Madikizela, Lawrence Mzukisi; Tavengwa, Nikita Tawanda; Chimuka, Luke

    2017-02-18

    In this review paper, the milestones and challenges that have been achieved and experienced by African Environmental Scientists regarding the assessment of water pollution caused by the presence of pharmaceutical compounds in water bodies are highlighted. The identification and quantification of pharmaceuticals in the African water bodies is important to the general public at large due to the lack of information. The consumption of pharmaceuticals to promote human health is usually followed by excretion of these drugs via urine or fecal matter due to their slight transformation in the human metabolism. Therefore, large amounts of pharmaceuticals are being discharged continuously from wastewater treatment plants into African rivers due to inefficiency of employed sewage treatment processes. Large portions of African communities do not even have proper sanitation systems which results in direct contamination of water resources with human waste that contains pharmaceutical constituents among other pollutants. Therefore, this article provides the overview of the recent studies published, mostly from 2012 to 2016, that have focused on the occurrence of different classes of pharmaceuticals in African aqueous systems. Also, the current analytical methods that are being used in Africa for pharmaceutical quantification in environmental waters are highlighted. African Scientists have started to investigate the materials and remediation processes for the elimination of pharmaceuticals from water.

  8. 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…

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

    PubMed Central

    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

  10. 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

  11. Bi-directional evolutionary level set method for topology optimization

    NASA Astrophysics Data System (ADS)

    Zhu, Benliang; Zhang, Xianmin; Fatikow, Sergej; Wang, Nianfeng

    2015-03-01

    A bi-directional evolutionary level set method for solving topology optimization problems is presented in this article. The proposed method has three main advantages over the standard level set method. First, new holes can be automatically generated in the design domain during the optimization process. Second, the dependency of the obtained optimized configurations upon the initial configurations is eliminated. Optimized configurations can be obtained even being started from a minimum possible initial guess. Third, the method can be easily implemented and is computationally more efficient. The validity of the proposed method is tested on the mean compliance minimization problem and the compliant mechanisms topology optimization problem.

  12. 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…

  13. 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…

  14. 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.

  15. 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.

  16. 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…

  17. 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

  18. A 3D Level Set Method for Microwave Breast Imaging

    PubMed Central

    Colgan, Timothy J.; Hagness, Susan C.; Van Veen, Barry D.

    2015-01-01

    Objective Conventional inverse-scattering algorithms for microwave breast imaging result in moderate resolution images with blurred boundaries between tissues. Recent 2D numerical microwave imaging studies demonstrate that the use of a level set method preserves dielectric boundaries, resulting in a more accurate, higher resolution reconstruction of the dielectric properties distribution. Previously proposed level set algorithms are computationally expensive and thus impractical in 3D. In this paper we present a computationally tractable 3D microwave imaging algorithm based on level sets. Methods We reduce the computational cost of the level set method using a Jacobian matrix, rather than an adjoint method, to calculate Frechet derivatives. We demonstrate the feasibility of 3D imaging using simulated array measurements from 3D numerical breast phantoms. We evaluate performance by comparing full 3D reconstructions to those from a conventional microwave imaging technique. We also quantitatively assess the efficacy of our algorithm in evaluating breast density. Results Our reconstructions of 3D numerical breast phantoms improve upon those of a conventional microwave imaging technique. The density estimates from our level set algorithm are more accurate than those of conventional microwave imaging, and the accuracy is greater than that reported for mammographic density estimation. Conclusion Our level set method leads to a feasible level of computational complexity for full 3D imaging, and reconstructs the heterogeneous dielectric properties distribution of the breast more accurately than conventional microwave imaging methods. Significance 3D microwave breast imaging using a level set method is a promising low-cost, non-ionizing alternative to current breast imaging techniques. PMID:26011863

  19. A PDE-Based Fast Local Level Set Method

    NASA Astrophysics Data System (ADS)

    Peng, Danping; Merriman, Barry; Osher, Stanley; Zhao, Hongkai; Kang, Myungjoo

    1999-11-01

    We develop a fast method to localize the level set method of Osher and Sethian (1988, J. Comput. Phys.79, 12) and address two important issues that are intrinsic to the level set method: (a) how to extend a quantity that is given only on the interface to a neighborhood of the interface; (b) how to reset the level set function to be a signed distance function to the interface efficiently without appreciably moving the interface. This fast local level set method reduces the computational effort by one order of magnitude, works in as much generality as the original one, and is conceptually simple and easy to implement. Our approach differs from previous related works in that we extract all the information needed from the level set function (or functions in multiphase flow) and do not need to find explicitly the location of the interface in the space domain. The complexity of our method to do tasks such as extension and distance reinitialization is O(N), where N is the number of points in space, not O(N log N) as in works by Sethian (1996, Proc. Nat. Acad. Sci. 93, 1591) and Helmsen and co-workers (1996, SPIE Microlithography IX, p. 253). This complexity estimation is also valid for quite general geometrically based front motion for our localized method.

  20. FDR-FET: an optimizing gene set enrichment analysis method.

    PubMed

    Ji, Rui-Ru; Ott, Karl-Heinz; Yordanova, Roumyana; Bruccoleri, Robert E

    2011-01-01

    Gene set enrichment analysis for analyzing large profiling and screening experiments can reveal unifying biological schemes based on previously accumulated knowledge represented as "gene sets". Most of the existing implementations use a fixed fold-change or P value cutoff to generate regulated gene lists. However, the threshold selection in most cases is arbitrary, and has a significant effect on the test outcome and interpretation of the experiment. We developed a new gene set enrichment analysis method, ie, FDR-FET, which dynamically optimizes the threshold choice and improves the sensitivity and selectivity of gene set enrichment analysis. The procedure translates experimental results into a series of regulated gene lists at multiple false discovery rate (FDR) cutoffs, and computes the P value of the overrepresentation of a gene set using a Fisher's exact test (FET) in each of these gene lists. The lowest P value is retained to represent the significance of the gene set. We also implemented improved methods to define a more relevant global reference set for the FET. We demonstrate the validity of the method using a published microarray study of three protease inhibitors of the human immunodeficiency virus and compare the results with those from other popular gene set enrichment analysis algorithms. Our results show that combining FDR with multiple cutoffs allows us to control the error while retaining genes that increase information content. We conclude that FDR-FET can selectively identify significant affected biological processes. Our method can be used for any user-generated gene list in the area of transcriptome, proteome, and other biological and scientific applications.

  1. 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

  2. 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.

  3. FDR-FET: an optimizing gene set enrichment analysis method

    PubMed Central

    Ji, Rui-Ru; Ott, Karl-Heinz; Yordanova, Roumyana; Bruccoleri, Robert E

    2011-01-01

    Gene set enrichment analysis for analyzing large profiling and screening experiments can reveal unifying biological schemes based on previously accumulated knowledge represented as “gene sets”. Most of the existing implementations use a fixed fold-change or P value cutoff to generate regulated gene lists. However, the threshold selection in most cases is arbitrary, and has a significant effect on the test outcome and interpretation of the experiment. We developed a new gene set enrichment analysis method, ie, FDR-FET, which dynamically optimizes the threshold choice and improves the sensitivity and selectivity of gene set enrichment analysis. The procedure translates experimental results into a series of regulated gene lists at multiple false discovery rate (FDR) cutoffs, and computes the P value of the overrepresentation of a gene set using a Fisher’s exact test (FET) in each of these gene lists. The lowest P value is retained to represent the significance of the gene set. We also implemented improved methods to define a more relevant global reference set for the FET. We demonstrate the validity of the method using a published microarray study of three protease inhibitors of the human immunodeficiency virus and compare the results with those from other popular gene set enrichment analysis algorithms. Our results show that combining FDR with multiple cutoffs allows us to control the error while retaining genes that increase information content. We conclude that FDR-FET can selectively identify significant affected biological processes. Our method can be used for any user-generated gene list in the area of transcriptome, proteome, and other biological and scientific applications. PMID:21918636

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

    PubMed

    Seedat, Jaishika; Penn, Claire

    2016-02-16

    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.

  5. 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…

  6. 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.

  7. Text Messaging to Improve Hypertension Medication Adherence in African Americans From Primary Care and Emergency Department Settings: Results From Two Randomized Feasibility Studies

    PubMed Central

    Hirzel, Lindsey; Dawood, Rachelle M; Dawood, Katee L; Nichols, Lauren P; Artinian, Nancy T; Schwiebert, Loren; Yarandi, Hossein N; Roberson, Dana N; Plegue, Melissa A; Mango, LynnMarie C; Levy, Phillip D

    2017-01-01

    Background Hypertension (HTN) is an important problem in the United States, with an estimated 78 million Americans aged 20 years and older suffering from this condition. Health disparities related to HTN are common in the United States, with African Americans suffering from greater prevalence of the condition than whites, as well as greater severity, earlier onset, and more complications. Medication adherence is an important component of HTN management, but adherence is often poor, and simply forgetting to take medications is often cited as a reason. Mobile health (mHealth) strategies have the potential to be a low-cost and effective method for improving medication adherence that also has broad reach. Objective Our goal was to determine the feasibility, acceptability, and preliminary clinical effectiveness of BPMED, an intervention designed to improve medication adherence among African Americans with uncontrolled HTN, through fully automated text messaging support. Methods We conducted two parallel, unblinded randomized controlled pilot trials with African-American patients who had uncontrolled HTN, recruited from primary care and emergency department (ED) settings. In each trial, participants were randomized to receive either usual care or the BPMED intervention for one month. Data were collected in-person at baseline and one-month follow-up, assessing the effect on medication adherence, systolic and diastolic blood pressure (SBP and DBP), medication adherence self-efficacy, and participant satisfaction. Data for both randomized controlled pilot trials were analyzed separately and combined. Results A total of 58 primary care and 65 ED participants were recruited with retention rates of 91% (53/58) and 88% (57/65), respectively. BPMED participants consistently showed numerically greater, yet nonsignificant, improvements in measures of medication adherence (mean change 0.9, SD 2.0 vs mean change 0.5, SD 1.5, P=.26), SBP (mean change –12.6, SD 24.0 vs mean change

  8. Chloride-free set accelerated cement compositions and methods

    SciTech Connect

    Fry, S.E.; Totten, P.L.; Childs, J.D.; Lindsey, D.W.

    1992-07-07

    This patent describes a method of cementing a conduit in a well bore penetrating a subterranean formation. It comprises introducing a cement composition into the space between the conduit and the walls of the well bore, the cement composition consisting essentially of hydraulic cement, water and a set tine accelerator.

  9. An introduction to standard setting methods in dentistry.

    PubMed

    Puryer, J; O'Sullivan, D

    2015-10-09

    The aim of this paper is to give readers an overview of contemporary standard setting methods used within dental education, and to provide a better understanding of the subject. We hope that it will be of benefit not just to those in academic dentistry, but all practitioners involved with both undergraduate and postgraduate assessment.

  10. Pattern of chronic myeloid leukemia in the imatinib era in a Sub-Saharan African setting.

    PubMed

    Faye, Blaise Felix; Dieng, Nata; Seck, Moussa; Gadji, Macoura; Gueye, Youssou Bamar; Sy, Diariatou; Toure, Sokhna Aissatou; Sall, Abibatou; Toure, Awa Oumar; Dieye, Tandakha Ndiaye; Diop, Saliou

    2016-10-01

    Chronic myeloid leukemia (CML) is an orphan disease in Africa because of the inaccessibility to specific treatment and the high cost of diagnosis and monitoring patients. The aim of this study was to report CML treatment response in a developing country in the tyrosine kinase inhibitor era. We conducted a longitudinal study of our cohort of CML patients. Socio-demographic, diagnosis, therapeutic, and treatment response parameters were studied. Sokal score, disease phase at diagnosis, delay from diagnosis to treatment, and treatment response were analyzed for their impact on survival. Fifty-five patients with a diagnosis of CML and who received treatment with imatinib for a minimum of 3 months were included in this study. Median follow-up was 170 patient-years. The sex ratio (M/F) was 1.62 and median age at diagnosis was 42 years. At diagnosis, 85.5 % of the patients were in chronic phase (CP), 12.7 % in accelerated phase (AP), and 1.8 % in blast crisis (BC). Sokal risk score distribution was as follows: low risk 29.8 %, intermediate risk 38.3 %, and high risk 31.9 %. Median time from first symptoms to first medical visit was 6.2 months and median time from first medical visit to cytogenetic and or molecular confirmation was 12.4 months. Mean delay time from first medical visit to imatinib initiation was 12.5 months (95 % CI 6.3-18.7). The complete hematologic response (CHR) at 3 months, the major cytogenetic response (MCR) at 12 months, and the major molecular response (MMR) at 24 months were respectively 82.4, 75, and 25 %. The 2-year overall survival rate was 81 %. Advanced phase at the diagnosis, discontinuation of imatinib therapy over 15 % of the time, lack of CHR at 3 months, lack of MCR at 12 months, and progression of the disease during imatinib therapy were associated with a risk of death (p ≤ 0.05). Our data confirm the improved prognosis of CML treated with imatinib in the setting of a developing country. However, response rates

  11. 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.

  12. Using the level set method to track ice sheet boundaries

    NASA Astrophysics Data System (ADS)

    Lindsey, D. S.; Dupont, T. K.

    2009-12-01

    Simulating ice-sheet volume changes requires tracking the interface of ice and its surrounding media, e.g. water, air, and sediment or rock. This can be challenging when using a fixed, or Eulerian, grid and allowing the interface to move via kinematic boundary conditions. For example, the interface may fall between grid points at a given point in time, making the application of boundary conditions less than straightforward. The level set method of Osher and Sethian (1988) offers an alternative approach, wherein a continuous level set function evolves within the domain via the combined kinematics of ice and its encompassing materials. The methods true strength lies in tracking the interface of two materials through time. Pralong and Funk (2004) applied this method to the movement of a glacier’s ice/air interface, offering a glimpse of the potential of this method for glaciology. Here we perform a simple preliminary test of the method for a two-dimensional (flow-line) model of an ice shelf, comparing the results to analytic approximations of the movement of both the ice/air interface and the ice front. Future experiments will incorporate grounded ice and include basal and lateral-shear stresses. The ultimate goal of this work is provide a practical approach for two and three-dimensional ice-sheet models to naturally track their moving boundaries.

  13. 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.

  14. 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

  15. A Level Set Method for vaporizing two-phase flows

    NASA Astrophysics Data System (ADS)

    Tanguy, Sébastien; Ménard, Thibaut; Berlemont, Alain

    2007-02-01

    Development and applications of numerical methods devoted to reactive interface simulations are presented. Emphasis is put on vaporization, where numerical difficulties arise in imposing accurate jump conditions for heat and mass transfers. We use both the Level Set Method and the Ghost Fluid Method to capture the interface motion accurately and to handle suitable jump conditions. A local vaporization mass flow rate per unit of surface area is defined and Stefan flow is involved in the process. Specific care has been devoted to the extension of discontinuous variables across the interface to populate ghost cells, in order to avoid parasitic currents and numerical diffusion across the interface. A projection method is set up to impose both the velocity field continuity and a divergence-free condition for the extended velocity field across the interface. The d2 law is verified in the numerical simulations of the vaporization of an isolated static drop. Results are then presented for a water droplet moving in air. Vapor mass fraction and temperature fields inside and outside the droplet are presented.

  16. The constrained reinitialization equation for level set methods

    NASA Astrophysics Data System (ADS)

    Hartmann, Daniel; Meinke, Matthias; Schröder, Wolfgang

    2010-03-01

    Based on the constrained reinitialization scheme [D. Hartmann, M. Meinke, W. Schröder, Differential equation based constrained reinitialization for level set methods, J. Comput. Phys. 227 (2008) 6821-6845] a new constrained reinitialization equation incorporating a forcing term is introduced. Two formulations for high-order constrained reinitialization (HCR) are presented combining the simplicity and generality of the original reinitialization equation [M. Sussman, P. Smereka, S. Osher, A level set approach for computing solutions to incompressible two-phase flow, J. Comput. Phys. 114 (1994) 146-159] in terms of high-order standard discretization and the accuracy of the constrained reinitialization scheme in terms of interface displacement. The novel HCR schemes represent simple extensions of standard implementations of the original reinitialization equation. The results evidence the significantly increased accuracy and robustness of the novel schemes.

  17. 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.

  18. Representing scientific data sets in KML: Methods and challenges

    NASA Astrophysics Data System (ADS)

    Ballagh, Lisa M.; Raup, Bruce H.; Duerr, Ruth E.; Khalsa, Siri Jodha S.; Helm, Christopher; Fowler, Doug; Gupte, Amruta

    2011-01-01

    Virtual Globes such as Google Earth and NASA World Wind permit users to explore rich imagery and the topography of the Earth. While other online services such as map servers provide ways to view, query, and download geographic information, the public has become captivated with the ability to view the Earth's features virtually. The National Snow and Ice Data Center began to display scientific data on Virtual Globes in 2006. The work continues to evolve with the production of high-quality Keyhole Markup Language (KML) representations of scientific data and an assortment of technical experiments. KML files are interoperable with many Virtual Globe or mapping software packages. This paper discusses the science benefits of Virtual Globes, summarizes KML creation methods, and introduces a guide for selecting tools and methods for authoring KML for use with scientific data sets.

  19. A test statistic for the affected-sib-set method.

    PubMed

    Lange, K

    1986-07-01

    This paper discusses generalizations of the affected-sib-pair method. First, the requirement that sib identity-by-descent relations be known unambiguously is relaxed by substituting sib identity-by-state relations. This permits affected sibs to be used even when their parents are unavailable for typing. In the limit of an infinite number of marker alleles each of infinitesimal population frequency, the identity-by-state relations coincide with the usual identity-by-descent relations. Second, a weighted pairs test statistic is proposed that covers affected sib sets of size greater than two. These generalizations make the affected-sib-pair method a more powerful technique for detecting departures from independent segregation of disease and marker phenotypes. A sample calculation suggests such a departure for tuberculoid leprosy and the HLA D locus.

  20. 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.

  1. 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

  2. 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.

  3. Improved PCR Methods for Detection of African Rabies and Rabies-Related Lyssaviruses ▿

    PubMed Central

    Coertse, Jessica; Weyer, Jacqueline; Nel, Louis H.; Markotter, Wanda

    2010-01-01

    Eleven different lyssavirus species, four of which occur on the African continent, are presently recognized. These viruses cause rabies, the burden of which is highest in the developing world, where routine laboratory diagnosis is often not available. From an epidemiological and control perspective, it is necessary that diagnostic methods detect the diversity of lyssaviruses present in different regions of the world. A published and widely used heminested reverse transcription-PCR (hnRT-PCR) was evaluated for its ability to detect a panel of diverse African lyssaviruses. Due to the limitations experienced for this assay, an alternative hnRT-PCR was developed. The new assay was found to be accurate and sensitive in the detection of African lyssavirus RNA in a variety of clinical specimens. The assay was further adapted to a real-time PCR platform to allow rapid, one-step, quantitative, and single-probe detection, and an internal control for the verification of sample preparation was included. The limit of detection of the real-time PCR assay was 10 RNA copies per reaction, with inter- and intra-assay variability below 4%. Subsequently, in demonstrating utility, both assays were successfully applied to antemortem rabies diagnosis in humans. We believe that the quantitative real-time PCR assay could find application as a routine confirmatory test for rabies diagnosis in the future and that it will serve as a valuable research tool in the biology of African lyssaviruses. Alternatively, the hnRT-PCR assay can be used in laboratories that do not have access to expensive real-time PCR equipment for sensitive diagnosis of lyssaviruses. PMID:20810772

  4. 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…

  5. 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

  6. Surgical experience on chronic constrictive pericarditis in African setting: review of 35 years’ experience in Cote d’Ivoire

    PubMed Central

    Tanauh, Yves; Meneas, Christophe; Diby, Florent; Adoubi, Anicet; Diomande, Manga

    2016-01-01

    Background Surgical experience with chronic constrictive pericarditis (CCP) is rarely documented in Africa; the aim of this study is therefore to review our African experience with CCP from 1977 to 2012 in terms of clinical and surgical outcomes and risk factors of early death after pericardiectomy. Methods This retrospective study is related to 120 patients with CCP; there were 72 men and 48 women with an average age at 28.8±10.4 years standard deviation (SD) (8–51 years). The main etiology was tuberculosis (99%). Symptoms secondary to systemic venous congestion were always present: patient were functionally classified according New York Heart Association (NYHA) functional classification: 63 patients presented in class II NYHA and 57 in class III or IV NYHA. The diagnosis confirmed by surgical report was: sub-acute CCP (n=12; 10%), fibrous CCP (n=36; 30%), calcified CCP (n=72; 60%). A pericardiectomy including an epicardiectomy with a systematic release of the ventricles was carried out in every case. Median sternotomy was frequently performed (n=117; 97.5%). Results Fifteen early deaths (12.5%) were observed, the cause of hospital deaths was due to a low cardiac output (n=12) and to a hepatic failure (n=3). Class III or IV (NYHA) (P=0.01), mitral regurgitation (P<0.05), persistent a diastolic syndrome after surgery (P<0.05) and low cardiac index (CI) (P<0.02) were the important risk factors. Age, size of cardiac X-ray silhouette, right and left ventricular diastolic pressures, ejection fraction (EF), atrial fibrillation and pericardial calcifications had no impact on early survival. The average follow up was 4 years (1–10 years); we lost 22 patients during follow-up. Among survivors, there was no late death; the patients were in class I or II NYHA. Post-operative catheterization evaluation (n=30) shown a significant decrease of the right and left ventricular end-diastolic pressures (P<0.05), of the pulmonary capillary wedge pressure (PCWP) (P<0.05) and of

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

    PubMed Central

    2012-01-01

    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. PMID:22856507

  8. 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.

  9. Search area Expanding Strategy and Dynamic Priority Setting Method in the Improved 2-opt Method

    NASA Astrophysics Data System (ADS)

    Matayoshi, Mitsukuni; Nakamura, Morikazu; Miyagi, Hayao

    We propose a new 2-opt base method in a Memetic algorithm, that is, Genetic Algorithms(GAs) with a local search. The basic idea is from the fast 2-opt(1) method and the improved 2-opt method(20). Our new search method uses the “Priority" employed in the improved 2-opt method. The “Priority" represents the contribution level in exchange of genes. Matayoshi's method exchanges genes based on previous contribution to the fitness value improvement. We propose a new search method by using the concept of the Priority. We call our method the search area expanding strategy method in the improved 2-opt method. Our method escalates the search area by using “Priority". In computer experiment, it is shown that the computation time to find exact solution depends on the value of the Priority. If our method does not set an appropriate priority beforehand, then we propose the method to adapt to suitable value. If improvement does not achieved for certain generations, our dynamic priority method tries to modify the priority by the mutation operation. Experimental results show that the search area expanding strategy method embedded with the dynamic priority setting method can find the exact solution at earlier generation than other methods for comparison.

  10. Setting the light conditions for measuring root transparency for age-at-death estimation methods.

    PubMed

    Adserias-Garriga, Joe; Nogué-Navarro, Laia; Zapico, Sara C; Ubelaker, Douglas H

    2017-03-30

    Age-at-death estimation is one of the main goals in forensic identification, being an essential parameter to determine the biological profile, narrowing the possibility of identification in cases involving missing persons and unidentified bodies. The study of dental tissues has been long considered as a proper tool for age estimation with several age estimation methods based on them. Dental age estimation methods can be divided into three categories: tooth formation and development, post-formation changes, and histological changes. While tooth formation and growth changes are important for fetal and infant consideration, when the end of dental and skeletal growth is achieved, post-formation or biochemical changes can be applied. Lamendin et al. in J Forensic Sci 37:1373-1379, (1992) developed an adult age estimation method based on root transparency and periodontal recession. The regression formula demonstrated its accuracy of use for 40 to 70-year-old individuals. Later on, Prince and Ubelaker in J Forensic Sci 47(1):107-116, (2002) evaluated the effects of ancestry and sex and incorporated root height into the equation, developing four new regression formulas for males and females of African and European ancestry. Even though root transparency is a key element in the method, the conditions for measuring this element have not been established. The aim of the present study is to set the light conditions measured in lumens that offer greater accuracy when applying the Lamendin et al. method modified by Prince and Ubelaker. The results must be also taken into account in the application of other age estimation methodologies using root transparency to estimate age-at-death.

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

    PubMed

    Noubiap, Jean Jacques N; Jingi, Ahmadou M; Kengne, André Pascal

    2014-10-01

    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.

  12. 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

  13. 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

  14. 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.

  15. A Performance Comparison Between a Level Set Method and an Unsplit Volume of Fluid Method

    NASA Astrophysics Data System (ADS)

    Desjardins, Olivier; Chiodi, Robert; Owkes, Mark

    2016-11-01

    The simulation of high density ratio liquid-gas flows presents many numerical difficulties due to the necessity to track the interface and the discontinuities in physical properties associated with the interface. Two main categories of methods used to track the interface are level set methods and volume of fluid (VOF) methods. In particular, conservative level set methods track and transport the interface using a scalar field, with the interface profile represented by a hyperbolic tangent function of a finite thickness. Volume of fluid methods, on the other hand, store the percentage of each fluid in the computational cells. Both methods offer distinct advantages, however, the strengths and weaknesses of each method relative to each other have yet to be thoroughly investigated. This work compares the accuracy and computational efficiency for an accurate conservative level set method and an unsplit VOF method using canonical test cases, such as Zalesak's disk, the deformation of a circle, and the deformation of a sphere. The mass conservation and ability to correctly predict instability for a more complex case of an air-blast atomization of a planar liquid layer will also be presented.

  16. Creating alliances for disease management in industrial settings: a case study of HIV/AIDS in workers in South African gold mines.

    PubMed

    Williams, B; Campbell, C

    1998-01-01

    The epidemic of HIV/AIDS is at an advanced stage in many African countries, but little attention has been given to the impact that this will have in industrial settings. Using the Southern African mining industry as a case study, the authors consider the state of the HIV epidemic and discuss programs that have been undertaken to manage HIV. They critically analyze the reasons current interventions have had little impact on HIV among mine workers, tracing the lack of success to neglect of the social and community contexts within which HIV transmission takes place, as well as the lack of attention to the psychosocial processes and mechanisms underlying disease transmission. Finally, they present an intervention that aims to address the limitations of existing industrial programs and improve the management of sexually transmitted diseases (STDs), including HIV, in a particular occupational setting through creating alliances between a wide range of community stakeholders. The intervention aims not only to reduce STDs, promote awareness of HIV risks, and distribute condoms, as existing programs have done, but also to address the broader social, cultural, and community contexts that facilitate HIV transmission.

  17. Overcoming barriers to priority setting using interdisciplinary methods.

    PubMed

    Peacock, Stuart; Mitton, Craig; Bate, Angela; McCoy, Bonnie; Donaldson, Cam

    2009-10-01

    Ten years ago, Holm's highly influential paper "Goodbye to the simple solutions: the second phase of priority setting" was published [Holm S. Goodbye to the simple solutions: the second phase of priority setting in health care. British Medical Journal 1998;317:1000-7]. Whilst attending the 2nd International Conference on Priorities in Health Care in London, Holm argued that the search for a rational set of decision-making rules was no longer adequate. Instead, the priority setting process itself was now thought to be more complex. Ten years later, the Conference returns to the UK for the first time, and it is timely to describe some new tools intended to assist both researchers and decision-makers seeking to develop both rational and fair and legitimate priority setting processes. In this paper we argue that to do so, researchers and decision-makers need to adopt an interdisciplinary and collaborative approach to priority setting. We focus on program budgeting and marginal analysis (PBMA) and bring together three hitherto separate interdisciplinary strands of the PBMA literature. Our aim is to assist researchers and decision-makers seeking to effectively develop and implement PBMA in practice. Specifically, we focus on the use of multi-criteria decision analysis, participatory action research, and accountability for reasonableness, drawn from the disciplines of decision analysis, sociology, and ethics respectively.

  18. 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

  19. Matrix method to find a new set of Zernike coefficients from an original set when the aperture radius is changed.

    PubMed

    Campbell, Charles E

    2003-02-01

    A matrix method is developed that allows a new set of Zernike coefficients that describe a surface or wave front appropriate for a new aperture size to be found from an original set of Zernike coefficients that describe the same surface or wave front but use a different aperture size. The new set of coefficients, arranged as elements of a vector, is formed by multiplying the original set of coefficients, also arranged as elements of a vector, by a conversion matrix formed from powers of the ratio of the new to the original aperture and elements of a matrix that forms the weighting coefficients of the radial Zernike polynomial functions. In developing the method, a new matrix method for expressing Zernike polynomial functions is introduced and used. An algorithm is given for creating the conversion matrix along with computer code to implement the algorithm.

  20. High Frequency Acoustic Propagation using Level Set Methods

    DTIC Science & Technology

    2007-01-01

    solution of the high frequency approximation to the wave equation. Traditional solutions to the Eikonal equation in high frequency acoustics are...curvature can be extracted at any point of the front from the level set function (provided the normal and curvature are well-defined at that point ), and... points per wavelength to resolve the wave). Ray tracing is therefore the current standard for high frequency propagation modeling. LSM may provide

  1. 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.

  2. Partitioning large data sets: Use of statistical methods applied to a set of Russian igneous-rock chemical analyses

    NASA Astrophysics Data System (ADS)

    Hernández Encinas, L.

    1994-12-01

    A method of cluster analysis has been applied on the following ideas: (a) stabilizing the variances of the variables; (b) reducing the number of variables by principal component analysis; and (c) generating a moderate number of groups containing large numbers of samples and applying a method of cluster analysis to them. This method was applied to a large data set to divide it into groups of samples without taking into consideration their origin. The sample set available consists of 1271 rock chemical analyses from 37 Massifs in the Ural Mountains (Russia), which then were divided into 6 differentiated groups. Later, discriminant functions were calculated to assign new samples to the groups determined.

  3. HMO employment and African-American physicians.

    PubMed Central

    Briscoe, Forrest; Konrad, Thomas R.

    2006-01-01

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

  4. Assessing the performance of methods to detect and quantify African dust in airborne particulates.

    PubMed

    Viana, Mar; Salvador, Pedro; Artíñano, Begoña; Querol, Xavier; Alastuey, Andrés; Pey, Jorge; Latz, Achim J; Cabañas, Mercè; Moreno, Teresa; García dos Santos, Saúl; Herce, María Dolores; Diez Hernández, Pablo; Romero García, Dolores; Fernández-Patier, Rosalía

    2010-12-01

    African dust (AD) contributions to particulate matter (PM) levels may be reported by Member States to the European Commission during justification of exceedances of the daily limit value (DLV). However, the detection and subsequent quantification of the AD contribution to PM levels is complex, and only two measurement-based methods are available in the literature: the Spanish-Portuguese reference method (SPR), and the Tel Aviv University method (TAU). In the present study, both methods were assessed. The SPR method was more conservative in the detection of episodes (71 days identified as AD by SPR, vs 81 by TAU), as it is less affected by interferences with local dust sources. The mean annual contribution of AD was lower with the TAU method than with SPR (2.7 vs 3.5 ± 1.5 μg/m(3)). The SPR and TAU AD time series were correlated with daily aluminum levels (a known tracer of AD), as well as with an AD source identified by the Positive Matrix Factorization (PMF) receptor model. Higher r(2) values were obtained with the SPR method than with TAU in both cases (r(2) = 0.72 vs 0.56, y = 0.05x vs y = 0.06x with aluminum levels; r(2)=0.79 vs 0.43, y = 0.8x vs y = 0.4x with the PMF source). We conclude that the SPR method is more adequate from an EU policy perspective (justification of DLV exceedances) due to the fact that it is more conservative than the TAU method. Based on our results, the TAU method requires adaptation of the thresholds in the algorithm to refine detection of low-impact episodes and avoid misclassification of local events as AD.

  5. The importance of broad, integrated data sets for mantle plume studies - South Atlantic combined with South African evidence

    NASA Astrophysics Data System (ADS)

    Class, C.

    2013-12-01

    Geochemistry alone cannot distinguish between shallow enriched sources and plume sources including deep recycled material, because both types are formed by differentiation processes near the surface of the Earth [1]. The observation of elevated 3He/4He isotope ratios above the values typical in MORB has been arguably the least equivocal geochemical tracer in support of mantle plumes from the lower mantle [2,3]. In the oceans, elevated 3He/4He isotope ratios are almost exclusively found in volcanic rocks related to an age-progressive track of seamounts, aseismic ridges or islands. Similarly, geochemically anomalously enriched MORB related to such an age-progressive track has been taken as evidence for plume-ridge interaction. The presence of continental material from shallow recycling has been suggested, in most cases, based on continental samples not spatially related to the respective oceanic basalts, but based on their extreme continental-type composition and/or continental material from other places. However, each of these arguments by themselves are equivocal. Here it is argued that putting oceanic basalt samples in a broader context allows better constraints on the origin of mantle plume geochemical signatures. For example, sampling continental material spatially related to oceanic basalts through rifting processes allow testing the role of shallow sources from recent continental breakup. In addition, sampling seamounts adjacent to bathymetric anomalies in the oceans can place constraints on the low temperature melting components in the upper mantle specific to this area, and thus allows distinction between plume and ambient mantle sources. This approach is applied to the source composition of the four South Atlantic plumes that have been related to the edge of the African LLSVP [4]. The Shona plume has been shown to be active for 80 Ma and its track extends to the African continental shelf [4]. Extending the age progression of this plume onto the continent

  6. 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…

  7. 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.

  8. 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...

  9. 48 CFR 19.502-4 - Methods of conducting set-asides.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 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...

  10. 48 CFR 19.502-5 - Methods of conducting set-asides.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Methods of conducting set... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 19.502-5 Methods of conducting set-asides. (a) Total small business set-asides may be conducted by using simplified acquisition...

  11. 48 CFR 19.502-5 - Methods of conducting set-asides.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Methods of conducting set... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 19.502-5 Methods of conducting set-asides. (a) Total small business set-asides may be conducted by using simplified acquisition...

  12. 48 CFR 19.502-5 - Methods of conducting set-asides.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Methods of conducting set... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 19.502-5 Methods of conducting set-asides. (a) Total small business set-asides may be conducted by using simplified acquisition...

  13. 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.

  14. 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

  15. 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.

  16. The impact of conventional dietary intake data coding methods on foods typically consumed by low-income African-American and White urban populations

    PubMed Central

    Mason, Marc A; Kuczmarski, Marie Fanelli; Allegro, Deanne; Zonderman, Alan B; Evans, Michele K

    2016-01-01

    Objective Analysing dietary data to capture how individuals typically consume foods is dependent on the coding variables used. Individual foods consumed simultaneously, like coffee with milk, are given codes to identify these combinations. Our literature review revealed a lack of discussion about using combination codes in analysis. The present study identified foods consumed at mealtimes and by race when combination codes were or were not utilized. Design Duplicate analysis methods were performed on separate data sets. The original data set consisted of all foods reported; each food was coded as if it was consumed individually. The revised data set was derived from the original data set by first isolating coded foods consumed as individual items from those foods consumed simultaneously and assigning a code to designate a combination. Foods assigned a combination code, like pancakes with syrup, were aggregated and associated with a food group, defined by the major food component (i.e. pancakes), and then appended to the isolated coded foods. Setting Healthy Aging in Neighborhoods of Diversity across the Life Span study. Subjects African-American and White adults with two dietary recalls (n 2177). Results Differences existed in lists of foods most frequently consumed by mealtime and race when comparing results based on original and revised data sets. African Americans reported consumption of sausage/luncheon meat and poultry, while ready-to-eat cereals and cakes/doughnuts/pastries were reported by Whites on recalls. Conclusions Use of combination codes provided more accurate representation of how foods were consumed by populations. This information is beneficial when creating interventions and exploring diet–health relationships. PMID:25435191

  17. 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…

  18. Student centred teaching methods in a Chinese setting.

    PubMed

    Clarke, Janice

    2010-01-01

    This paper offers a discussion about using Western, student centred teaching methods with Chinese student nurses. There is increasing interest from Chinese nurse educators in student centred learning and an increase in partnerships between Chinese and Western universities. This paper suggests that the assumption that Western teaching methods are superior is now questioned and transferring Western style teaching to China requires a high degree of cultural sensitivity.

  19. 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

  20. 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.

  1. Methods for Extracellular Vesicles Isolation in a Hospital Setting

    PubMed Central

    Sáenz-Cuesta, Matías; Arbelaiz, Ander; Oregi, Amaia; Irizar, Haritz; Osorio-Querejeta, Iñaki; Muñoz-Culla, Maider; Banales, Jesus M.; Falcón-Pérez, Juan M.; Olascoaga, Javier; Otaegui, David

    2015-01-01

    The research in extracellular vesicles (EVs) has been rising during the last decade. However, there is no clear consensus on the most accurate protocol to isolate and analyze them. Besides, most of the current protocols are difficult to implement in a hospital setting due to being very time-consuming or to requirements of specific infrastructure. Thus, our aim is to compare five different protocols (comprising two different medium-speed differential centrifugation protocols; commercially polymeric precipitation – exoquick – acid precipitation; and ultracentrifugation) for blood and urine samples to determine the most suitable one for the isolation of EVs. Nanoparticle tracking analysis, flow cytometry, western blot (WB), electronic microscopy, and spectrophotometry were used to characterize basic aspects of EVs such as concentration, size distribution, cell-origin and transmembrane markers, and RNA concentration. The highest EV concentrations were obtained using the exoquick protocol, followed by both differential centrifugation protocols, while the ultracentrifugation and acid-precipitation protocols yielded considerably lower EV concentrations. The five protocols isolated EVs of similar characteristics regarding markers and RNA concentration; however, standard protocol recovered only small EVs. EV isolated with exoquick presented difficult to be analyzed with WB. The RNA concentrations obtained from urine-derived EVs were similar to those obtained from blood-derived ones, despite the urine EV concentration being 10–20 times lower. We consider that a medium-speed differential centrifugation could be suitable to be applied in a hospital setting as it requires the simplest infrastructure and recovers higher concentration of EV than standard protocol. A workflow from sampling to characterization of EVs is proposed. PMID:25762995

  2. Differential magnetometer method applied to measurement of geomagnetically induced currents in Southern African power networks

    NASA Astrophysics Data System (ADS)

    Matandirotya, Electdom; Cilliers, Pierre. J.; Van Zyl, Robert R.; Oyedokun, David T.; Villiers, Jean

    2016-03-01

    Geomagnetically induced currents (GICs) in conductors connected to the Earth are driven by an electric field produced by a time-varying magnetic field linked to magnetospheric-ionospheric current perturbations during geomagnetic storms. The GIC measurements are traditionally done on the neutral-to-ground connections of power transformers. A method of inferring the characteristics of GIC in power lines using differential magnetic field measurements is presented. Measurements of the GIC in the power lines connected to a particular power transformer are valuable in the verification of the modeling of GIC in the power transmission network. The differential magnetometer method (DMM) is an indirect method used to estimate the GIC in a power line. With the DMM, low-frequency GIC in the power line is estimated from the difference between magnetic field recordings made directly underneath the power line and at some distance away, where the magnetic field of the GIC in the transmission line has negligible effect. Results of the first application of the DMM to two selected sites of the Southern African power transmission network are presented. The results show that good quality GIC measurements are achieved through the DMM using Commercially-Off-The-Shelf magnetometers.

  3. 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.

  4. 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.

  5. Optimum allocation of conservation funds and choice of conservation programs for a set of African cattle breeds

    PubMed Central

    Reist-Marti, Sabine B; Abdulai, Awudu; Simianer, Henner

    2006-01-01

    Although funds for livestock conservation are limited there is little known about the optimal allocation of conservation funds. A new algorithm was used to allocate Mio US$ 1, 2, 3, 5 or unlimited funds, discounted over 50 years, on 23 African cattle breeds conserved with four different possible conservation programs. Additionally, Mio US$ 1 was preferably allocated to breeds with special traits. The conceptional in situ conservation programs strongly involve breeders and give them part of the responsibility for the conservation of the breed. Therefore, the pure in situ conservation was more efficient than cryoconservation or combined in situ and cryoconservation. The average annual discounted conservation cost for a breed can be as low as US$ 1000 to US$ 4400 depending on the design of the conservation program and the economic situation of the country of conservation. The choice of the breeds and the optimal conservation program and the amount of money allocated to each breed depend on many factors such as the amount of funds available, the conservation potential of each breed, the effects of the conservation program as well as its cost. With Mio US$ 1, 64% of the present diversity could be maintained over 50 years, which is 13% more than would be maintained if no conservation measures were implemented. Special traits could be conserved with a rather small amount of the total funds. Diversity can not be conserved completely, not even with unlimited funds. A maximum of 92% of the present diversity could be conserved with Mio US$ 10, leaving 8% of the diversity to unpredictable happenings. The suggested algorithm proved to be useful for optimal allocation of conservation funds. It allocated the funds optimally among breeds by identifying the most suited conservation program for each breed, also accounting for differences in currency exchange rates between the different countries. PMID:16451794

  6. 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.

  7. The impact of HIV/SRH service integration on workload: analysis from the Integra Initiative in two African settings

    PubMed Central

    2014-01-01

    Background There is growing interest in integration of HIV and sexual and reproductive health (SRH) services as a way to improve the efficiency of human resources (HR) for health in low- and middle-income countries. Although this is supported by a wealth of evidence on the acceptability and clinical effectiveness of service integration, there is little evidence on whether staff in general health services can easily absorb HIV services. Methods We conducted a descriptive analysis of HR integration through task shifting/sharing and staff workload in the context of the Integra Initiative - a large-scale five-year evaluation of HIV/SRH integration. We describe the level, characteristics and changes in HR integration in the context of wider efforts to integrate HIV/SRH, and explore the impact of HR integration on staff workload. Results Improvements in the range of services provided by staff (HR integration) were more likely to be achieved in facilities which also improved other elements of integration. While there was no overall relationship between integration and workload at the facility level, HIV/SRH integration may be most influential on staff workload for provider-initiated HIV testing and counselling (PITC) and postnatal care (PNC) services, particularly where HIV care and treatment services are being supported with extra SRH/HIV staffing. Our findings therefore suggest that there may be potential for further efficiency gains through integration, but overall the pace of improvement is slow. Conclusions This descriptive analysis explores the effect of HIV/SRH integration on staff workload through economies of scale and scope in high- and medium-HIV prevalence settings. We find some evidence to suggest that there is potential to improve productivity through integration, but, at the same time, significant challenges are being faced, with the pace of productivity gain slow. We recommend that efforts to implement integration are assessed in the broader context of HR

  8. Can traditional birth attendants be trained to accurately identify septic infants, initiate antibiotics, and refer in a rural African setting?

    PubMed Central

    Gill, Christopher John; MacLeod, William B; Phiri-Mazala, Grace; Guerina, Nicholas G; Mirochnick, Mark; Knapp, Anna B; Hamer, Davidson H

    2014-01-01

    ABSTRACT Background: Neonatal sepsis is a major cause of neonatal mortality. In populations with limited access to health care, early identification of bacterial infections and initiation of antibiotics by community health workers (CHWs) could be lifesaving. It is unknown whether this strategy would be feasible using traditional birth attendants (TBAs), a cadre of CHWs who typically have limited training and educational backgrounds. Methods: We analyzed data from the intervention arm of a cluster-randomized trial involving TBAs in Lufwanyama District, Zambia, from June 2006 to November 2008. TBAs followed neonates for signs of potential infection through 28 days of life. If any of 16 criteria were met, TBAs administered oral amoxicillin and facilitated referral to a rural health center. Results: Our analysis included 1,889 neonates with final vital status by day 28. TBAs conducted a median of 2 (interquartile range 2–6) home visits (51.4% in week 1 and 48.2% in weeks 2–4) and referred 208 neonates (11%) for suspected sepsis. Of referred neonates, 176/208 (84.6%) completed their referral. Among neonates given amoxicillin, 171/183 (93.4%) were referred; among referred neonates, 171/208 (82.2%) received amoxicillin. Referral and/or initiation of antibiotics were strongly associated with neonatal death (for referral, relative risk [RR] = 7.93, 95% confidence interval [CI] = 4.4–14.3; for amoxicillin administration, RR = 4.7, 95% CI = 2.4–8.7). Neonates clinically judged to be “extremely sick” by the referring TBA were at greatest risk of death (RR = 8.61, 95% CI = 4.0–18.5). Conclusion: The strategy of administering a first dose of antibiotics and referring based solely on the clinical evaluation of a TBA is feasible and could be effective in reducing neonatal mortality in remote rural settings. PMID:25276591

  9. 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.

  10. Process Setting through General Linear Model and Response Surface Method

    NASA Astrophysics Data System (ADS)

    Senjuntichai, Angsumalin

    2010-10-01

    The objective of this study is to improve the efficiency of the flow-wrap packaging process in soap industry through the reduction of defectives. At the 95% confidence level, with the regression analysis, the sealing temperature, temperatures of upper and lower crimper are found to be the significant factors for the flow-wrap process with respect to the number/percentage of defectives. Twenty seven experiments have been designed and performed according to three levels of each controllable factor. With the general linear model (GLM), the suggested values for the sealing temperature, temperatures of upper and lower crimpers are 185, 85 and 85° C, respectively while the response surface method (RSM) provides the optimal process conditions at 186, 89 and 88° C. Due to different assumptions between percentage of defective and all three temperature parameters, the suggested conditions from the two methods are then slightly different. Fortunately, the estimated percentage of defectives at 5.51% under GLM process condition and the predicted percentage of defectives at 4.62% under RSM process condition are not significant different. But at 95% confidence level, the percentage of defectives under RSM condition can be much lower approximately 2.16% than those under GLM condition in accordance with wider variation. Lastly, the percentages of defectives under the conditions suggested by GLM and RSM are reduced by 55.81% and 62.95%, respectively.

  11. 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

  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 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

  13. Validation of transition analysis as a method of adult age estimation in a modern South African sample.

    PubMed

    Jooste, N; L'Abbé, E N; Pretorius, S; Steyn, M

    2016-09-01

    The use of advanced statistical methods, such as transition analysis, has transformed adult age estimation into a systematically and statistically appropriate practice. The method developed by Boldsen and colleagues (2002) uses 36 features from the cranial sutures, pubic symphysis and auricular surface to calculate maximum likelihood point estimates and 95% confidence intervals, using the ADBOU computer software. However, when using the method in a geographically and contextually distinct sample, such as South Africa, accuracy and precision is of concern. This study aimed to test the repeatability, accuracy and precision of the transition analysis method, using the ADBOU computer software, on a South African sample. Age estimations were generated, for 149 black individuals from the Pretoria Bone Collection, using three individual components as well as different combinations of components and prior distributions (uniform and informative). The informative prior distributions represented both an archaeological and a forensic context. Cohen's kappa statistic uncovered some failings in the scoring procedure. While the accuracy compared favourably with existing methods, the method lacked satisfactory precision. Although combining the components improved accuracy and precision, removing the cranium from the combination was beneficial in some instances. The influence of population variation was observed in the scoring procedure, reference sample and the prior distributions. Validity may be improved for a South African sample by adding age-related components that have been developed on a relevant population. A prior distribution based on South African mortality rates might also be beneficial.

  14. Developing and Exploiting a Unique Seismic Data Set from South African Gold Mines for Source Characterization and Wave Propagation

    DTIC Science & Technology

    2007-09-01

    the University of the Witwatersrand . RESEARCH ACCOMPLISHED Three complimentary data sets are being assembled in this project: (1) high...frequency in-mine seismic data from three mines along the northwestern edge of the Witwatersrand basin, (2) seismograms from mine events recorded at...Seismicity The Witwatersrand basin is part of a granite-greenstone complex constituting the basement of the Kaapvaal craton. The basement evolved

  15. African Pentecostalism

    ERIC Educational Resources Information Center

    Garrard, David J.

    2009-01-01

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

  16. 48 CFR 3419.502-4 - Methods of conducting set-asides.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Methods of conducting set... ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 3419.502-4 Methods of conducting set-asides. (a) Simplified acquisition procedures as described in FAR Part 13...

  17. 48 CFR 3419.502-4 - Methods of conducting set-asides.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Methods of conducting set... ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 3419.502-4 Methods of conducting set-asides. (a) Simplified acquisition procedures as described in FAR Part 13...

  18. 48 CFR 3419.502-4 - Methods of conducting set-asides.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Methods of conducting set... ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 3419.502-4 Methods of conducting set-asides. (a) Simplified acquisition procedures as described in FAR part 13...

  19. 48 CFR 3419.502-4 - Methods of conducting set-asides.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Methods of conducting set... ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Set-Asides for Small Business 3419.502-4 Methods of conducting set-asides. (a) Simplified acquisition procedures as described in FAR Part 13...

  20. Convergence of hausdorff approximation methods for the Edgeworth-Pareto hull of a compact set

    NASA Astrophysics Data System (ADS)

    Efremov, R. V.

    2015-11-01

    The Hausdorff methods comprise an important class of polyhedral approximation methods for convex compact bodies, since they have an optimal convergence rate and possess other useful properties. The concept of Hausdorff methods is extended to a problem arising in multicriteria optimization, namely, to the polyhedral approximation of the Edgeworth-Pareto hull (EPH) of a convex compact set. It is shown that the sequences of polyhedral sets generated by Hausdorff methods converge to the EPH to be approximated. It is shown that the Estimate Refinement method, which is most frequently used to approximate the EPH of convex compact sets, is a Hausdorff method and, hence, generates sequences of sets converging to the EPH.

  1. 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…

  2. 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.

  3. A multiple data set phylogeny for the endemic South African freshwater phreatoicidean isopod genus Mesamphisopus: Taxonomic and biogeographic implications.

    PubMed

    Gouws, G; Matthee, C A; Stewart, B A

    2010-05-01

    The obligate, freshwater isopod suborder Phreatoicidea is represented in South Africa by ten species contained within the endemic genus Mesamphisopus (Mesamphisopidae). Here, phylogenetic hypotheses are proposed to describe the evolutionary and biogeographic history of the genus with respect to drainage basin evolution and to assess species diversity, particularly among populations variably identified as Mesamphisopusabbreviatus or Mesamphisopusdepressus. Twenty-three ingroup taxa were examined, including eight known species and representatives of the M. abbreviatus-depressus complex. Allozyme data from 12 loci were analysed phenetically and cladistically. Mitochondrial DNA sequence data from the 12S ribosomal RNA and cytochrome c oxidase subunit I genes were analysed as a combined mtDNA data set and as a total data set in combination with recoded allele frequency data. Analyses retrieved (1) a monophyletic Mesamphisopus; (2) Mesamphisopustsitsikamma and a Mesamphisopuspaludosus+Mesamphisopuspenicillatus clade as basal lineages; (3) a Mesamphisopuscapensis+Mesamphisopusbaccatus clade; and (4) a clade containing the M. abbreviatus-depressus complex, with these taxa nested among several other species. Large genetic distances among taxa and the paraphyly of the members of the M. abbreviatus-depressus complex suggested the presence of hidden taxonomic diversity in Mesamphisopus. Clear biogeographic patterns emerged with lineages and clades mostly restricted to geographically discrete regions. Patterns showed remarkable similarity to those seen in the region's terrestrial fauna and bore no relation to the history of drainage basins. These patterns suggested that vicariance and, possibly, limited dispersal events played a major role in the evolution of Mesamphisopus.

  4. 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.

  5. 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

  6. Methods to Determine Recommended Feeder-Wide Advanced Inverter Settings for Improving Distribution System Performance

    SciTech Connect

    Rylander, Matthew; Reno, Matthew J.; Quiroz, Jimmy E.; Ding, Fei; Li, Huijuan; Broderick, Robert J.; Mather, Barry; Smith, Jeff

    2016-11-21

    This paper describes methods that a distribution engineer could use to determine advanced inverter settings to improve distribution system performance. These settings are for fixed power factor, volt-var, and volt-watt functionality. Depending on the level of detail that is desired, different methods are proposed to determine single settings applicable for all advanced inverters on a feeder or unique settings for each individual inverter. Seven distinctly different utility distribution feeders are analyzed to simulate the potential benefit in terms of hosting capacity, system losses, and reactive power attained with each method to determine the advanced inverter settings.

  7. The Relationship Between Body Fat Percentage and Body Mass Index in Overweight and Obese Individuals in an Urban African Setting

    PubMed Central

    Phillips, Julie S.; Igumbor, Ehimario U.

    2016-01-01

    The increase in the prevalence of overweight and obesity in both developed and developing countries is associated with musculoskeletal and other non-communicable diseases. To address this, an accurate measure of body adiposity, bearing in mind several shortcomings of body mass index (BMI), should be used. This study determined the relationship between BMI and body fat (BF)% among adult Nigerians of different ethnic groups residing in an urban setting. Using multistage cluster sampling technique were recruited 1571 subjects (>18 years; male=51.2%) in a cross-sectional study. Body adiposity indices were assessed using BMI and BF%. Using BF%, the result shows that a total number of 156 (9.9%) had low BF% while 291 (18.5%) had very high BF%, while the BMI classifications of body adiposity, 68 (4.3%) were underweight while 271 (17.3%) were obese. There was a strong and positive statistical relationship between BF% and BMI when both were paired without controlling for gender and age (r=0.81, P<0.01). The results show that there is a strong positive association between BMI and BF%, and age and sex are predictors of this association. PMID:28299149

  8. A minimization method on the basis of embedding the feasible set and the epigraph

    NASA Astrophysics Data System (ADS)

    Zabotin, I. Ya; Shulgina, O. N.; Yarullin, R. S.

    2016-11-01

    We propose a conditional minimization method of the convex nonsmooth function which belongs to the class of cutting-plane methods. During constructing iteration points a feasible set and an epigraph of the objective function are approximated by the polyhedral sets. In this connection, auxiliary problems of constructing iteration points are linear programming problems. In optimization process there is some opportunity of updating sets which approximate the epigraph. These updates are performed by periodically dropping of cutting planes which form embedding sets. Convergence of the proposed method is proved, some realizations of the method are discussed.

  9. 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

  10. 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

    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.

  11. Monitoring programme revision highlights long-term salinity changes in selected South African rivers and the value of comprehensive long-term data sets.

    PubMed

    van Niekerk, H; Silberbauer, M J; Hohls, B C

    2009-07-01

    Determination of data adequacy for detection of long-term salinity changes was an important task in the revision of the South African National Chemical Monitoring Programme (NCMP). The NCMP has been running for more than 30 years with several hundred active monitoring sites. Twenty-five sites on major rivers had sufficient continuous data for the estimation of salinity changes over a 25-year period and statistically significant upward or downward trends occurred at 17 of the 25 sites. Most sites were too far apart for detailed analysis of whole river systems, though an upward trend is apparent in the Lower Orange River and a downward trend in the Great Fish River. Salinity in the Tugela River remained stable, well below the 70 mS m( - 1) guideline for drinking water. The results underline the importance of long-term data sets for assessing and managing aquatic systems and provide the impetus to continue building and maintaining long-term sampling programmes.

  12. 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…

  13. 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."…

  14. 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.

  15. 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.

  16. Schumann Resonance spectra decomposition method and studies of the locations of the African thunderstorm centres

    NASA Astrophysics Data System (ADS)

    Dyrda, Michal; Kulak, Andrzej; Mlynarczyk, Janusz; Ostrowski, Michal; Kubisz, Jerzy; Michalec, Adam; Nieckarz, Zenon

    2014-05-01

    The idea, that the global atmospheric electric circuit is driven by global lightning activity was introduced at the beginning of the last century. Today, the different observational methods are used from satellites to the radio observations performed in the extremely low frequency (ELF) range to evaluate local as well as global lightning activity, its spatial and temporal variability and influence on our planet and Earth's climate. The ground-based thunderstorms observations, particularly ELF, also allow the measurements of the dipole moment of discharges. Global lightning activity excites the Earth-ionosphere cavity and the produced electromagnetic radiation is responsible for generating the Schumann resonance (SR). The interaction of the standing and travelling waves leads to asymmetric shape of the observational SR power spectra picks, which was noticed by Kułak et al. (2006). They proposed a spectral decomposition method, what allows to separate the resonant field from the travelling wave contribution, which can be dominant at small distances from the sources. In such approach, one can apply the inverse problem solution for determining a distance of the dominant signal source. The distances to the thunderstorm centres are calculated using the numerical as well as the analytical models for the electromagnetic waves propagation in the Earth-ionosphere cavity. The ELF electromagnetic waves, recorded by Hylaty ELF station, located in South-East of Poland are used to derive the distances to the most powerful thunderstorm centres located in Africa and hence to obtain 1-D thunderstorm lightning activity maps. The observational data taken in January and August 2011 were binned in 10 minute intervals and SR power spectra were derived. Then a curve describing seven asymmetric SR maxima was fitted to the spectrum for each time interval. We use chi-squared test to compare the resulted decomposed power spectra with curves obtained within the considered numerical and

  17. Diagnostic Profiles: A Standard Setting Method for Use with a Cognitive Diagnostic Model

    ERIC Educational Resources Information Center

    Skaggs, Gary; Hein, Serge F.; Wilkins, Jesse L. M.

    2016-01-01

    This article introduces the Diagnostic Profiles (DP) standard setting method for setting a performance standard on a test developed from a cognitive diagnostic model (CDM), the outcome of which is a profile of mastered and not-mastered skills or attributes rather than a single test score. In the DP method, the key judgment task for panelists is a…

  18. 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.

  19. Preventing Cognitive Decline in Older African Americans with Mild Cognitive Impairment: Design and Methods of a Randomized Clinical Trial

    PubMed Central

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

    2012-01-01

    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

  20. 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

  1. Benchmarking DFT methods with small basis sets for the calculation of halogen-bond strengths.

    PubMed

    Siiskonen, Antti; Priimagi, Arri

    2017-02-01

    In recent years, halogen bonding has become an important design tool in crystal engineering, supramolecular chemistry and biosciences. The fundamentals of halogen bonding have been studied extensively with high-accuracy computational methods. Due to its non-covalency, the use of triple-zeta (or larger) basis sets is often recommended when studying halogen bonding. However, in the large systems often encountered in supramolecular chemistry and biosciences, large basis sets can make the calculations far too slow. Therefore, small basis sets, which would combine high computational speed and high accuracy, are in great demand. This study focuses on comparing how well density functional theory (DFT) methods employing small, double-zeta basis sets can estimate halogen-bond strengths. Several methods with triple-zeta basis sets are included for comparison. Altogether, 46 DFT methods were tested using two data sets of 18 and 33 halogen-bonded complexes for which the complexation energies have been previously calculated with the high-accuracy CCSD(T)/CBS method. The DGDZVP basis set performed far better than other double-zeta basis sets, and it even outperformed the triple-zeta basis sets. Due to its small size, it is well-suited to studying halogen bonding in large systems.

  2. 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.

  3. Method/basis set dependence of NICS values among metallic nano-clusters and hydrocarbons.

    PubMed

    Badri, Zahra; Foroutan-Nejad, Cina; Rashidi-Ranjbar, Parviz

    2012-03-14

    The influence of various all-electron basis sets and effective core potentials employed along with several DFT functionals (B3LYP, B3PW91, BLYP, BP86 and M06) on the magnitude of nucleus independent chemical shift (NICS) values in different metallic nano-clusters and hydrocarbons is studied. In general, it is demonstrated that the NICS values are very sensitive to the applied method/basis set; however, the method/basis set dependence is more prominent for computed NICS values in transition metal clusters. In hydrocarbons, medium-size basis sets perform roughly similar to large basis sets in most cases. It is also found that NICS(0) values are more sensitive to the method/basis set variation compared to the NICS values computed at 1 or 2 Å above the ring plane. However, in many cases, no broad-spectrum regulation is found for the effect of basis set/method on the magnitude of NICS values. A detailed study showed that bond length alternation in a molecule has an insignificant effect on the magnitude of NICS values so the influence of method/basis sets on the magnitude of NICS values mostly arises from the different predicted ring current intensities at various computational levels.

  4. The rising burden of diabetes and hypertension in southeast asian and african regions: need for effective strategies for prevention and control in primary health care settings.

    PubMed

    Mohan, Viswanathan; Seedat, Yackoob K; Pradeepa, Rajendra

    2013-01-01

    Aim. To review the available literature on burden of diabetes mellitus (DM) and hypertension (HTN) and its coexistence in Southeast Asian (SEA) and the African (AFR) regions and to suggest strategies to improve DM and HTN prevention and control in primary health care (PHC) in the two regions. Methods. A systematic review of the papers published on DM, HTN, and prevention/control of chronic diseases in SEA and AFR regions between 1980 and December 2012 was included. Results. In the year 2011, SEA region had the second largest number of people with DM (71.4 million), while the AFR region had the smallest number (14.7 million). Screening studies identified high proportions (>50%) of individuals with previously undiagnosed HTN and DM in both of the SEA and AFR regions. Studies from both regions have shown that DM and HTN coexist in type 2 DM ranging from 20.6% in India to 78.4% in Thailand in the SEA region and ranging from 9.7% in Nigeria to 70.4% in Morocco in the AFR region. There is evidence that by lifestyle modification both DM and HTN can be prevented. Conclusion. To meet the twin challenge of DM and HTN in developing countries, PHCs will have to be strengthened with a concerted and multipronged effort to provide promotive, preventive, curative, and rehabilitative services.

  5. The Rising Burden of Diabetes and Hypertension in Southeast Asian and African Regions: Need for Effective Strategies for Prevention and Control in Primary Health Care Settings

    PubMed Central

    Mohan, Viswanathan; Seedat, Yackoob K.; Pradeepa, Rajendra

    2013-01-01

    Aim. To review the available literature on burden of diabetes mellitus (DM) and hypertension (HTN) and its coexistence in Southeast Asian (SEA) and the African (AFR) regions and to suggest strategies to improve DM and HTN prevention and control in primary health care (PHC) in the two regions. Methods. A systematic review of the papers published on DM, HTN, and prevention/control of chronic diseases in SEA and AFR regions between 1980 and December 2012 was included. Results. In the year 2011, SEA region had the second largest number of people with DM (71.4 million), while the AFR region had the smallest number (14.7 million). Screening studies identified high proportions (>50%) of individuals with previously undiagnosed HTN and DM in both of the SEA and AFR regions. Studies from both regions have shown that DM and HTN coexist in type 2 DM ranging from 20.6% in India to 78.4% in Thailand in the SEA region and ranging from 9.7% in Nigeria to 70.4% in Morocco in the AFR region. There is evidence that by lifestyle modification both DM and HTN can be prevented. Conclusion. To meet the twin challenge of DM and HTN in developing countries, PHCs will have to be strengthened with a concerted and multipronged effort to provide promotive, preventive, curative, and rehabilitative services. PMID:23573413

  6. 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.

  7. Organic and elemental carbon filter sets: preparation method and interlaboratory results.

    PubMed

    Chai, Ming; Birch, M Eileen; Deye, Greg

    2012-10-01

    Carbonaceous aerosols play an important role in climate, visibility, air quality, and human health effects, and they have been routinely monitored in workplace and environmental settings. Different thermal analysis methods have been applied to determine the carbon content of carbonaceous aerosols. Good agreement between results for total carbon (TC) generally has been found, but the organic and elemental carbon (OC and EC) fractions determined by different methods often disagree. Measurement uncertainty is mainly due to pyrolysis and charring of OC sample components. Lack of reference materials has impeded progress on method standardization and understanding method biases. A relatively simple method for generating matched filter sets having known OC-EC contents is reported. After generation and analysis of each set to confirm agreement between filters, the filter sets were distributed to six laboratories for an interlaboratory comparison. Analytical results indicate a uniform carbon distribution for the filter sets and good agreement between the participating laboratories. Relative standard deviations (RSDs) for mean TC (OC + EC), OC, and EC results for seven laboratories were <10, 11, and 12% (respectively). Except for one EC result (RSD = 16%), RSDs reported by individual laboratories for TC, OC, and EC were <12%. The method of filter generation is generally applicable and reproducible. Depending on the application, different filter loadings and types of OC materials can be employed. Matched filter sets prepared by the described approach can be used for determining the accuracy of OC-EC methods and thereby contribute to method standardization.

  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. 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…

  10. 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…

  11. Application of penalty function method to computation of reachable sets for control systems with state constraints

    NASA Astrophysics Data System (ADS)

    Gusev, M. I.

    2016-10-01

    We study the penalty function type methods for computing the reachable sets of nonlinear control systems with state constraints. The state constraints are given by a finite system of smooth inequalities. The proposed methods are based on removing the state constraints by replacing the original system with an auxiliary system without constraints. This auxiliary system is obtained by modifying the set of velocities of the original system around the boundary of constraints. The right-hand side of the system depends on a penalty parameter. We prove that the reachable sets of the auxiliary system approximate in the Hausdorff metric the reachable set of the original system with state constraints as the penalty parameter tends to zero (infinity) and give the estimates of the rate of convergence. The numerical algorithms for computing the reachable sets, based on Pontryagin's maximum principle, are also considered.

  12. Existence and blowup results for asymptotically Euclidean initial data sets generated by the conformal method

    NASA Astrophysics Data System (ADS)

    Dilts, James; Isenberg, James

    2016-11-01

    For each set of (freely chosen) seed data, the conformal method reduces the Einstein constraint equations to a system of elliptic equations, the conformal constraint equations. We prove an admissibility criterion, based on a (conformal) prescribed scalar curvature problem, which provides a necessary condition on the seed data for the conformal constraint equations to (possibly) admit a solution. We then consider sets of asymptotically Euclidean (AE) seed data for which solutions of the conformal constraint equations exist, and examine the blowup properties of these solutions as the seed data sets approach sets for which no solutions exist. We also prove that there are AE seed data sets which include a Yamabe nonpositive metric and lead to solutions of the conformal constraints. These data sets allow the mean curvature function to have 0's.

  13. 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.

  14. Kernel Density Estimation, Kernel Methods, and Fast Learning in Large Data Sets.

    PubMed

    Wang, Shitong; Wang, Jun; Chung, Fu-lai

    2014-01-01

    Kernel methods such as the standard support vector machine and support vector regression trainings take O(N(3)) time and O(N(2)) space complexities in their naïve implementations, where N is the training set size. It is thus computationally infeasible in applying them to large data sets, and a replacement of the naive method for finding the quadratic programming (QP) solutions is highly desirable. By observing that many kernel methods can be linked up with kernel density estimate (KDE) which can be efficiently implemented by some approximation techniques, a new learning method called fast KDE (FastKDE) is proposed to scale up kernel methods. It is based on establishing a connection between KDE and the QP problems formulated for kernel methods using an entropy-based integrated-squared-error criterion. As a result, FastKDE approximation methods can be applied to solve these QP problems. In this paper, the latest advance in fast data reduction via KDE is exploited. With just a simple sampling strategy, the resulted FastKDE method can be used to scale up various kernel methods with a theoretical guarantee that their performance does not degrade a lot. It has a time complexity of O(m(3)) where m is the number of the data points sampled from the training set. Experiments on different benchmarking data sets demonstrate that the proposed method has comparable performance with the state-of-art method and it is effective for a wide range of kernel methods to achieve fast learning in large data sets.

  15. Effect of the absolute statistic on gene-sampling gene-set analysis methods.

    PubMed

    Nam, Dougu

    2015-03-02

    Gene-set enrichment analysis and its modified versions have commonly been used for identifying altered functions or pathways in disease from microarray data. In particular, the simple gene-sampling gene-set analysis methods have been heavily used for datasets with only a few sample replicates. The biggest problem with this approach is the highly inflated false-positive rate. In this paper, the effect of absolute gene statistic on gene-sampling gene-set analysis methods is systematically investigated. Thus far, the absolute gene statistic has merely been regarded as a supplementary method for capturing the bidirectional changes in each gene set. Here, it is shown that incorporating the absolute gene statistic in gene-sampling gene-set analysis substantially reduces the false-positive rate and improves the overall discriminatory ability. Its effect was investigated by power, false-positive rate, and receiver operating curve for a number of simulated and real datasets. The performances of gene-set analysis methods in one-tailed (genome-wide association study) and two-tailed (gene expression data) tests were also compared and discussed.

  16. Promoting Language and Executive Function in Educational Settings: The Drežancic Method

    ERIC Educational Resources Information Center

    Cozzani, Francesca; Zanobini, Mirella; Usai, Maria Carmen

    2016-01-01

    Research Findings: This study aims to evaluate the efficacy of linguistic training based on the use of the Drežancic method in educational settings. It is hypothesized that characteristics of this method, based on the typical stages of linguistic and cognitive development, could influence both language competence and executive function (EF). A…

  17. 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,…

  18. Advancing Understanding of the Characteristics and Capacity of African American Women Who Serve as Lay Health Advisors in Community-Based Settings

    ERIC Educational Resources Information Center

    Shelton, Rachel C.; Dunston, Sheba King; Leoce, Nicole; Jandorf, Lina; Thompson, Hayley S.; Erwin, Deborah O.

    2017-01-01

    Lay Health Advisor (LHA) programs hold tremendous promise for reducing health disparities and addressing social determinants of health in medically underserved communities, including African American populations. Very little is understood about the capacity of LHAs in these roles and the broader contributions they make to their communities. This…

  19. 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…

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. A review of statistical methods for data sets with multiple censoring points

    SciTech Connect

    Gilbert, R.O.

    1995-07-06

    This report reviews and summarizes recent literature on statistical methods for analyzing data sets that are censored by multiple censoring points. This report is organized as follows. Following the introductory comments in Section 2, a brief discussion of detection limits is given in Section 3. Sections 4 and 5 focus on data analysis methods for estimating parameters and testing hypotheses, respectively, when data sets are left censored with multiple censoring points. A list of publications that deal with a variety of other applications for censored data sets is provided in Section 6. Recommendations on future research for developing new or improved tools for statistically analyzing multiple left-censored data sets are provided in Section 7. The list of references is in Section 8.

  6. 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.

  7. Adapting and Evaluating a Rapid, Low-Cost Method to Enumerate Flies in the Household Setting.

    PubMed

    Wolfe, Marlene K; Dentz, Holly N; Achando, Beryl; Mureithi, MaryAnne; Wolfe, Tim; Null, Clair; Pickering, Amy J

    2017-02-08

    Diarrhea is a leading cause of death among children under 5 years of age worldwide. Flies are important vectors of diarrheal pathogens in settings lacking networked sanitation services. There is no standardized method for measuring fly density in households; many methods are cumbersome and unvalidated. We adapted a rapid, low-cost fly enumeration technique previously developed for industrial settings, the Scudder fly grill, for field use in household settings. We evaluated its performance in comparison to a sticky tape fly trapping method at latrine and food preparation areas among households in rural Kenya. The grill method was more sensitive; it detected the presence of any flies at 80% (433/543) of sampling locations versus 64% (348/543) of locations by the sticky tape. We found poor concordance between the two methods, suggesting that standardizing protocols is important for comparison of fly densities between studies. Fly species identification was feasible with both methods; however, the sticky tape trap allowed for more nuanced identification. Both methods detected a greater presence of bottle flies near latrines compared with food preparation areas (P < 0.01). The grill method detected more flies at the food preparation area compared with near the latrine (P = 0.014) while the sticky tape method detected no difference. We recommend the Scudder grill as a sensitive fly enumeration tool that is rapid and low cost to implement.

  8. Adapting and Evaluating a Rapid, Low-Cost Method to Enumerate Flies in the Household Setting

    PubMed Central

    Wolfe, Marlene K.; Dentz, Holly N.; Achando, Beryl; Mureithi, MaryAnne; Wolfe, Tim; Null, Clair; Pickering, Amy J.

    2017-01-01

    Diarrhea is a leading cause of death among children under 5 years of age worldwide. Flies are important vectors of diarrheal pathogens in settings lacking networked sanitation services. There is no standardized method for measuring fly density in households; many methods are cumbersome and unvalidated. We adapted a rapid, low-cost fly enumeration technique previously developed for industrial settings, the Scudder fly grill, for field use in household settings. We evaluated its performance in comparison to a sticky tape fly trapping method at latrine and food preparation areas among households in rural Kenya. The grill method was more sensitive; it detected the presence of any flies at 80% (433/543) of sampling locations versus 64% (348/543) of locations by the sticky tape. We found poor concordance between the two methods, suggesting that standardizing protocols is important for comparison of fly densities between studies. Fly species identification was feasible with both methods; however, the sticky tape trap allowed for more nuanced identification. Both methods detected a greater presence of bottle flies near latrines compared with food preparation areas (P < 0.01). The grill method detected more flies at the food preparation area compared with near the latrine (P = 0.014) while the sticky tape method detected no difference. We recommend the Scudder grill as a sensitive fly enumeration tool that is rapid and low cost to implement. PMID:27956654

  9. Use of simulated data sets to evaluate the fidelity of metagenomic processing methods.

    PubMed

    Mavromatis, Konstantinos; Ivanova, Natalia; Barry, Kerrie; 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

    2007-06-01

    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.

  10. 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.

  11. A variational approach to path planning in three dimensions using level set methods

    NASA Astrophysics Data System (ADS)

    Cecil, Thomas; Marthaler, Daniel E.

    2006-01-01

    In this paper we extend the two-dimensional methods set forth in [T. Cecil, D. Marthaler, A variational approach to search and path planning using level set methods, UCLA CAM Report, 04-61, 2004], proposing a variational approach to a path planning problem in three dimensions using a level set framework. After defining an energy integral over the path, we use gradient flow on the defined energy and evolve the entire path until a locally optimal steady state is reached. We follow the framework for motion of curves in three dimensions set forth in [P. Burchard, L.-T. Cheng, B. Merriman, S. Osher, Motion of curves in three spatial dimensions using a level set approach, J. Comput. Phys. 170(2) (2001) 720-741], modified appropriately to take into account that we allow for paths with positive, varying widths. Applications of this method extend to robotic motion and visibility problems, for example. Numerical methods and algorithms are given, and examples are presented.

  12. Weld defect detection on digital radiographic image using level set method

    NASA Astrophysics Data System (ADS)

    Halim, Suhaila Abd; Petrus, Bertha Trissan; Ibrahim, Arsmah; Manurung, Yupiter HP; Jayes, Mohd Idris

    2013-09-01

    Segmentation is the most critical task and widely used to obtain useful information in image processing. In this study, Level set based on Chan Vese method is explored and applied to define weld defect on digital radiographic image and its accuracy is evaluated to measure its performance. A set of images with region of interest (ROI) that contain defect are used as input image. The ROI image is pre-processed to improve their quality for better detection. Then, the image is segmented using level set method that is implemented using MATLAB R2009a. The accuracy of the method is evaluated using Receiver Operating Characteristic (ROC). Experimental results show that the method generated an area underneath the ROC of 0.7 in the set of images and the operational point reached corresponds to 0.6 of sensitivity and 0.8 of specificity. The application of segmentation technique such as Chan-Vese level set able to assist radiographer in detecting the defect on digital radiographic image accurately.

  13. 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.

  14. A level-set method for thermal motion of bubbles and droplets

    NASA Astrophysics Data System (ADS)

    Balcázar, Néstor; Oliva, Assensi; Rigola, Joaquim

    2016-09-01

    A conservative level-set model for direct simulation of two-phase flows with thermocapillary effects at dynamically deformable interface is presented. The Navier-Stokes equations coupled with the energy conservation equation are solved by means of a finite-volume/level-set method. Some numerical examples including thermocapillary motion of single and multiple fluid particles are computed by means of the present method. The results are compared with analytical solutions and numerical results from the literature as validations of the proposed model.

  15. 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

  16. Structural topology design of container ship based on knowledge-based engineering and level set method

    NASA Astrophysics Data System (ADS)

    Cui, Jin-ju; Wang, De-yu; Shi, Qi-qi

    2015-06-01

    Knowledge-Based Engineering (KBE) is introduced into the ship structural design in this paper. From the implementation of KBE, the design solutions for both Rules Design Method (RDM) and Interpolation Design Method (IDM) are generated. The corresponding Finite Element (FE) models are generated. Topological design of the longitudinal structures is studied where the Gaussian Process (GP) is employed to build the surrogate model for FE analysis. Multi-objective optimization methods inspired by Pareto Front are used to reduce the design tank weight and outer surface area simultaneously. Additionally, an enhanced Level Set Method (LSM) which employs implicit algorithm is applied to the topological design of typical bracket plate which is used extensively in ship structures. Two different sets of boundary conditions are considered. The proposed methods show satisfactory efficiency and accuracy.

  17. Comparing and refining karst disturbance index methods through application in an island karst setting

    NASA Astrophysics Data System (ADS)

    Porter, Brandon L.; North, Leslie A.; Polk, Jason S.

    2016-12-01

    The interconnected nature of surface and subsurface karst environments allows easy disturbance to their aquifers and specialized ecosystems from anthropogenic impacts. The karst disturbance index is a holistic tool used to measure disturbance to karst environments and has been applied and refined through studies in Florida and Italy, among others. Through these applications, the karst disturbance index has evolved into two commonly used methods of application; yet, the karst disturbance index is still susceptible to evaluation and modification for application in other areas around the world. The geographically isolated and highly vulnerable municipality of Arecibo, Puerto Rico's karst area provides an opportunity to test the usefulness and validity of the karst disturbance index in an island setting and to compare and further refine the application of the original and modified methods. This study found the both methods of karst disturbance index application resulted in high disturbance scores (Original Method 0.54 and Modified Method 0.69, respectively) and uncovered multiple considerations for the improvement of the karst disturbance index. An evaluation of multiple methods together in an island setting also resulted in the need for adding additional indicators, including Mogote Removal and Coastal Karst. Collectively, the results provide a holistic approach to using the karst disturbance index in an island karst setting and suggest a modified method by which scaling and weighting may compensate for the difference between the original and modified method scores and allow interested stakeholders to evaluate disturbance regardless of his or her level of expertise.

  18. Comparing and refining karst disturbance index methods through application in an island karst setting.

    PubMed

    Porter, Brandon L; North, Leslie A; Polk, Jason S

    2016-12-01

    The interconnected nature of surface and subsurface karst environments allows easy disturbance to their aquifers and specialized ecosystems from anthropogenic impacts. The karst disturbance index is a holistic tool used to measure disturbance to karst environments and has been applied and refined through studies in Florida and Italy, among others. Through these applications, the karst disturbance index has evolved into two commonly used methods of application; yet, the karst disturbance index is still susceptible to evaluation and modification for application in other areas around the world. The geographically isolated and highly vulnerable municipality of Arecibo, Puerto Rico's karst area provides an opportunity to test the usefulness and validity of the karst disturbance index in an island setting and to compare and further refine the application of the original and modified methods. This study found the both methods of karst disturbance index application resulted in high disturbance scores (Original Method 0.54 and Modified Method 0.69, respectively) and uncovered multiple considerations for the improvement of the karst disturbance index. An evaluation of multiple methods together in an island setting also resulted in the need for adding additional indicators, including Mogote Removal and Coastal Karst. Collectively, the results provide a holistic approach to using the karst disturbance index in an island karst setting and suggest a modified method by which scaling and weighting may compensate for the difference between the original and modified method scores and allow interested stakeholders to evaluate disturbance regardless of his or her level of expertise.

  19. Basis set generation for quantum dynamics simulations using simple trajectory-based methods.

    PubMed

    Saller, Maximilian A C; Habershon, Scott

    2015-01-13

    Methods for solving the time-dependent Schrödinger equation generally employ either a global static basis set, which is fixed at the outset, or a dynamic basis set, which evolves according to classical-like or variational equations of motion; the former approach results in the well-known exponential scaling with system size, while the latter can suffer from challenging numerical problems, such as singular matrices, as well as violation of energy conservation. Here, we suggest a middle road: building a basis set using trajectories to place time-independent basis functions in the regions of phase space relevant to wave function propagation. This simple approach, which potentially circumvents many of the problems traditionally associated with global or dynamic basis sets, is successfully demonstrated for two challenging benchmark problems in quantum dynamics, namely, relaxation dynamics following photoexcitation in pyrazine, and the spin Boson model.

  20. A chance-constrained programming level set method for longitudinal segmentation of lung tumors in CT.

    PubMed

    Rouchdy, Youssef; Bloch, Isabelle

    2011-01-01

    This paper presents a novel stochastic level set method for the longitudinal tracking of lung tumors in computed tomography (CT). The proposed model addresses the limitations of registration based and segmentation based methods for longitudinal tumor tracking. It combines the advantages of each approach using a new probabilistic framework, namely Chance-Constrained Programming (CCP). Lung tumors can shrink or grow over time, which can be reflected in large changes of shape, appearance and volume in CT images. Traditional level set methods with a priori knowledge about shape are not suitable since the tumors are undergoing random and large changes in shape. Our CCP level set model allows to introduce a flexible prior to track structures with a highly variable shape by permitting a constraint violation of the prior up to a specified probability level. The chance constraints are computed from two given points by the user or from segmented tumors from a reference image. The reference image can be one of the images studied or an external template. We present a numerical scheme to approximate the solution of the proposed model and apply it to track lung tumors in CT. Finally, we compare our approach with a Bayesian level set. The CCP level set model gives the best results: it is more coherent with the manual segmentation.

  1. 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.

  2. A new automatic parameter setting method of a simplified PCNN for image segmentation.

    PubMed

    Chen, Yuli; Park, Sung-Kee; Ma, Yide; Ala, Rajeshkanna

    2011-06-01

    An automatic parameter setting method of a simplified pulse coupled neural network (SPCNN) is proposed here. Our method successfully determines all the adjustable parameters in SPCNN and does not need any training and trials as required by previous methods. In order to achieve this goal, we try to derive the general formulae of dynamic threshold and internal activity of the SPCNN according to the dynamic properties of neurons, and then deduce the sub-intensity range expression of each segment based on the general formulae. Besides, we extract information from an input image, such as the standard deviation and the optimal histogram threshold of the image, and attempt to build a direct relation between the dynamic properties of neurons and the static properties of each input image. Finally, the experimental segmentation results of the gray natural images from the Berkeley Segmentation Dataset, rather than synthetic images, prove the validity and efficiency of our proposed automatic parameter setting method of SPCNN.

  3. 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.

  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. 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.

  6. 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…

  7. Level set method coupled with Energy Image features for brain MR image segmentation.

    PubMed

    Punga, Mirela Visan; Gaurav, Rahul; Moraru, Luminita

    2014-06-01

    Up until now, the noise and intensity inhomogeneity are considered one of the major drawbacks in the field of brain magnetic resonance (MR) image segmentation. This paper introduces the energy image feature approach for intensity inhomogeneity correction. Our approach of segmentation takes the advantage of image features and preserves the advantages of the level set methods in region-based active contours framework. The energy image feature represents a new image obtained from the original image when the pixels' values are replaced by local energy values computed in the 3×3 mask size. The performance and utility of the energy image features were tested and compared through two different variants of level set methods: one as the encompassed local and global intensity fitting method and the other as the selective binary and Gaussian filtering regularized level set method. The reported results demonstrate the flexibility of the energy image feature to adapt to level set segmentation framework and to perform the challenging task of brain lesion segmentation in a rather robust way.

  8. 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;…

  9. 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.

  10. 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

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

    PubMed

    Altendorfer, Klaus; Hübl, Alexander; Jodlbauer, Herbert

    2014-08-18

    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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. An automatic method for fast and accurate liver segmentation in CT images using a shape detection level set method

    NASA Astrophysics Data System (ADS)

    Lee, Jeongjin; Kim, Namkug; Lee, Ho; Seo, Joon Beom; Won, Hyung Jin; Shin, Yong Moon; Shin, Yeong Gil

    2007-03-01

    Automatic liver segmentation is still a challenging task due to the ambiguity of liver boundary and the complex context of nearby organs. In this paper, we propose a faster and more accurate way of liver segmentation in CT images with an enhanced level set method. The speed image for level-set propagation is smoothly generated by increasing number of iterations in anisotropic diffusion filtering. This prevents the level-set propagation from stopping in front of local minima, which prevails in liver CT images due to irregular intensity distributions of the interior liver region. The curvature term of shape modeling level-set method captures well the shape variations of the liver along the slice. Finally, rolling ball algorithm is applied for including enhanced vessels near the liver boundary. Our approach are tested and compared to manual segmentation results of eight CT scans with 5mm slice distance using the average distance and volume error. The average distance error between corresponding liver boundaries is 1.58 mm and the average volume error is 2.2%. The average processing time for the segmentation of each slice is 5.2 seconds, which is much faster than the conventional ones. Accurate and fast result of our method will expedite the next stage of liver volume quantification for liver transplantations.

  17. 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.

  18. 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…

  19. 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

  20. 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

  1. Segmentation of ventricles in Alzheimer mr images using anisotropic diffusion filtering and level set method.

    PubMed

    Anandh, K R; Sujatha, C M; Ramakrishnan, S

    2014-01-01

    Ventricle enlargement is a useful structural biomarker for the diagnosis of Alzheimer’s Disease (AD). This devastating neurodegenerative disorder results in progression of dementia. Although AD results in the passive increment of ventricle volume, there exists a large overlap in the volume measurements of AD and normal subjects. Hence, shape based analysis of ventricle dilation is appropriate to detect the subtle morphological changes among these two groups. In this work, segmentation of ventricle in Alzheimer MR images is employed using level set method and anisotropic based diffusion filtering. Images considered for this study are preprocessed using filters. Anisotropic based diffusion filtering is employed to extract the edge map. This filtering performs region specific smoothing process using the diffusion coefficient as a function of image gradient. Filtered images are subjected to level set method which employs an improved diffusion rate equation for the level set evolution. Geometric features are extracted from the segmented ventricles. Results show that the diffusion filter could extract edge map with sharp region boundaries. The modified level set method is able to extract the morphological changes in ventricles. The observed morphological changes are distinct for normal and AD subjects (p < 0.0001). It is also observed that the sizes of ventricle in the AD subjects are noticeably enlarged when compared to normal subjects. Features obtained from the segmented ventricles are also clearly distinct and demonstrate the differences in the AD subjects. As ventricle volume and its morphometry are significant biomarkers, this study seems to be clinically relevant.

  2. Setting priorities in global child health research investments: guidelines for implementation of CHNRI method.

    PubMed

    Rudan, Igor; Gibson, Jennifer L; Ameratunga, Shanthi; El Arifeen, Shams; Bhutta, Zulfiqar A; Black, Maureen; Black, Robert E; Brown, Kenneth H; Campbell, Harry; Carneiro, Ilona; Chan, Kit Yee; Chandramohan, Daniel; Chopra, Mickey; Cousens, Simon; Darmstadt, Gary L; Meeks Gardner, Julie; Hess, Sonja Y; Hyder, Adnan A; Kapiriri, Lydia; Kosek, Margaret; Lanata, Claudio F; Lansang, Mary Ann; Lawn, Joy; Tomlinson, Mark; Tsai, Alexander C; Webster, Jayne

    2008-12-01

    This article provides detailed guidelines for the implementation of systematic method for setting priorities in health research investments that was recently developed by Child Health and Nutrition Research Initiative (CHNRI). The target audience for the proposed method are international agencies, large research funding donors, and national governments and policy-makers. The process has the following steps: (i) selecting the managers of the process; (ii) specifying the context and risk management preferences; (iii) discussing criteria for setting health research priorities; (iv) choosing a limited set of the most useful and important criteria; (v) developing means to assess the likelihood that proposed health research options will satisfy the selected criteria; (vi) systematic listing of a large number of proposed health research options; (vii) pre-scoring check of all competing health research options; (viii) scoring of health research options using the chosen set of criteria; (ix) calculating intermediate scores for each health research option; (x) obtaining further input from the stakeholders; (xi) adjusting intermediate scores taking into account the values of stakeholders; (xii) calculating overall priority scores and assigning ranks; (xiii) performing an analysis of agreement between the scorers; (xiv) linking computed research priority scores with investment decisions; (xv) feedback and revision. The CHNRI method is a flexible process that enables prioritizing health research investments at any level: institutional, regional, national, international, or global.

  3. 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

  4. Comparison between advected-field and level-set methods in the study of vesicle dynamics

    NASA Astrophysics Data System (ADS)

    Maitre, E.; Misbah, C.; Peyla, P.; Raoult, A.

    2012-07-01

    Phospholipidic membranes and vesicles constitute a basic element in real biological functions. Vesicles are viewed as a model system to mimic basic viscoelastic behaviors of some cells, like red blood cells. Phase field and level-set models are powerful tools to tackle dynamics of membranes and their coupling to the flow. These two methods are somewhat similar, but to date no bridge between them has been made. This is a first focus of this paper, where we show how the phase-field methods developed in Biben and Misbah (2003) [7], Beaucourt (2004) [9], Biben (2005) [33] for immersed vesicles could be considered as a level-set method for a particular strain-stress relationship. The main conclusion is that the two methods share several common features and we shall provide the correspondence between the two methods. Furthermore, a constitutive viscoelastic law is derived for the composite fluid: the ambient fluid and the membranes. We present two different approaches to deal with the membrane local incompressibility, and point out differences. Some numerical results following from the level-set approach are presented.

  5. A comparative assessment of different methods for detecting inhomogeneities in Turkish temperature data set

    NASA Astrophysics Data System (ADS)

    Tayanç, Mete; Nüzhet Dalfes, H.; Karaca, Mehmet; Yenigün, Orhan

    1998-04-01

    A combination of different methods is described whereby climatological time series can be tested for inhomogeneities using relative homogeneity techniques. The method set includes graphical analysis, a non-parametric Kruskal-Wallis homogeneity test and a Wald-Wolfowitz runs test application to the annual mean difference temperature series between highly correlated stations. A series of Monte Carlo simulation studies was carried out, which determined the inhomogeneity detection efficiencies of these tests. The procedure is statistically rigorous and provides estimates of the time and magnitude of change in the mean. Its application to annual mean temperature differences series for 82 Turkish climate stations indicates that the method set is a valuable tool for testing time series.

  6. 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.

  7. 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

  8. 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

  9. 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)

  10. A cluster randomized trial of standard quality improvement versus patient-centered interventions to enhance depression care for African Americans in the primary care setting: study protocol NCT00243425

    PubMed Central

    2010-01-01

    Background Several studies document disparities in access to care and quality of care for depression for African Americans. Research suggests that patient attitudes and clinician communication behaviors may contribute to these disparities. Evidence links patient-centered care to improvements in mental health outcomes; therefore, quality improvement interventions that enhance this dimension of care are promising strategies to improve treatment and outcomes of depression among African Americans. This paper describes the design of the BRIDGE (Blacks Receiving Interventions for Depression and Gaining Empowerment) Study. The goal of the study is to compare the effectiveness of two interventions for African-American patients with depression--a standard quality improvement program and a patient-centered quality improvement program. The main hypothesis is that patients in the patient-centered group will have a greater reduction in their depression symptoms, higher rates of depression remission, and greater improvements in mental health functioning at six, twelve, and eighteen months than patients in the standard group. The study also examines patient ratings of care and receipt of guideline-concordant treatment for depression. Methods/Design A total of 36 primary care clinicians and 132 of their African-American patients with major depressive disorder were recruited into a cluster randomized trial. The study uses intent-to-treat analyses to compare the effectiveness of standard quality improvement interventions (academic detailing about depression guidelines for clinicians and disease-oriented care management for their patients) and patient-centered quality improvement interventions (communication skills training to enhance participatory decision-making for clinicians and care management focused on explanatory models, socio-cultural barriers, and treatment preferences for their patients) for improving outcomes over 12 months of follow-up. Discussion The BRIDGE Study

  11. A level set method for cupping artifact correction in cone-beam CT

    SciTech Connect

    Xie, Shipeng; Li, Haibo; Ge, Qi; Li, Chunming

    2015-08-15

    Purpose: To reduce cupping artifacts and improve the contrast-to-noise ratio in cone-beam computed tomography (CBCT). Methods: A level set method is proposed to reduce cupping artifacts in the reconstructed image of CBCT. The authors derive a local intensity clustering property of the CBCT image and define a local clustering criterion function of the image intensities in a neighborhood of each point. This criterion function defines an energy in terms of the level set functions, which represent a segmentation result and the cupping artifacts. The cupping artifacts are estimated as a result of minimizing this energy. Results: The cupping artifacts in CBCT are reduced by an average of 90%. The results indicate that the level set-based algorithm is practical and effective for reducing the cupping artifacts and preserving the quality of the reconstructed image. Conclusions: The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented, and provides cupping correction through a single-scan acquisition. The experimental results demonstrate that the proposed method successfully reduces the cupping artifacts.

  12. 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

  13. Stabilized Conservative Level Set Method with Adaptive Wavelet-based Mesh Refinement

    NASA Astrophysics Data System (ADS)

    Shervani-Tabar, Navid; Vasilyev, Oleg V.

    2016-11-01

    This paper addresses one of the main challenges of the conservative level set method, namely the ill-conditioned behavior of the normal vector away from the interface. An alternative formulation for reconstruction of the interface is proposed. Unlike the commonly used methods which rely on the unit normal vector, Stabilized Conservative Level Set (SCLS) uses a modified renormalization vector with diminishing magnitude away from the interface. With the new formulation, in the vicinity of the interface the reinitialization procedure utilizes compressive flux and diffusive terms only in the normal direction to the interface, thus, preserving the conservative level set properties, while away from the interfaces the directional diffusion mechanism automatically switches to homogeneous diffusion. The proposed formulation is robust and general. It is especially well suited for use with adaptive mesh refinement (AMR) approaches due to need for a finer resolution in the vicinity of the interface in comparison with the rest of the domain. All of the results were obtained using the Adaptive Wavelet Collocation Method, a general AMR-type method, which utilizes wavelet decomposition to adapt on steep gradients in the solution while retaining a predetermined order of accuracy.

  14. 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.

  15. 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.

  16. Bio-molecule Surfaces Construction via a Higher-Order Level-Set Method.

    PubMed

    Bajaj, Chandrajit L; Xu, Guo-Liang; Zhang, Qin

    2008-11-01

    We present a general framework for a higher-order spline level-set (HLS) method and apply this to bio-molecule surfaces construction. Starting from a first order energy functional, we obtain a general level set formulation of geometric partial differential equation, and provide an efficient approach to solve this partial differential equation using a C(2) spline basis. We also present a fast cubic spline interpolation algorithm based on convolution and the Z-transform, which exploits the local relationship of interpolatory cubic spline coefficients with respect to given function data values. One example of our HLS method is demonstrated, which is the construction of bio-molecule surfaces (an implicit solvation interface) with their individual atomic coordinates and solvated radii as prerequisite.

  17. A level set-based shape optimization method for periodic sound barriers composed of elastic scatterers

    NASA Astrophysics Data System (ADS)

    Hashimoto, Hiroshi; Kim, Min-Geun; Abe, Kazuhisa; Cho, Seonho

    2013-10-01

    This paper presents a level set-based topology optimization method for noise barriers formed from an assembly of scatterers. The scattering obstacles are modeled by elastic bodies arranged periodically along the wall. Due to the periodicity, the problem can be reduced to that in a unit cell. The interaction between the elastic scatterers and the acoustic field is described in the context of the level set analysis. The semi-infinite acoustic wave regions located on the both sides of the barrier are represented by impedance matrices. The objective function is defined by the energy transmission passing the barrier. The design sensitivity is evaluated analytically by the aid of adjoint equations. The dependency of the optimal profile on the stiffness of scatterers and on the target frequency band is examined. The feasibility of the developed optimization method is proved through numerical examples.

  18. Advancing Understanding of the Characteristics and Capacity of African American Women Who Serve as Lay Health Advisors in Community-Based Settings.

    PubMed

    Shelton, Rachel C; Dunston, Sheba King; Leoce, Nicole; Jandorf, Lina; Thompson, Hayley S; Erwin, Deborah O

    2017-02-01

    Lay Health Advisor (LHA) programs hold tremendous promise for reducing health disparities and addressing social determinants of health in medically underserved communities, including African American populations. Very little is understood about the capacity of LHAs in these roles and the broader contributions they make to their communities. This article seeks to address this gap by describing the characteristics and capacity of a sample of 76 female African American LHAs from a nationally disseminated evidence-based LHA program for breast and cervical cancer screening (The National Witness Project), as well as potential differences between cancer survivors and nonsurvivors who serve as LHAs. A conceptual model for understanding LHA capacity and contributions in underserved communities at the individual, social, and organizational levels is presented. We describe LHA experiences and characteristics (e.g., experiences of mistrust and discrimination, racial pride, sociodemographics), capacity at the individual level (e.g., psychological and physical health, health behaviors), capacity at the social level (e.g., social networks, social support), and capacity at the organizational level (e.g., role-related competencies, self-efficacy, leadership, role benefits/challenges). Data were obtained through interview-administered telephone surveys between 2010 and 2011. Findings highlight the critical capacity that LHAs bring to their communities and the importance of supporting LHAs to sustain these programs and to address racial/ethnic health disparities.

  19. 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…

  20. Restoration of clipped seismic waveforms using projection onto convex sets method

    NASA Astrophysics Data System (ADS)

    Zhang, Jinhai; Hao, Jinlai; Zhao, Xu; Wang, Shuqin; Zhao, Lianfeng; Wang, Weimin; Yao, Zhenxing

    2016-12-01

    The seismic waveforms would be clipped when the amplitude exceeds the upper-limit dynamic range of seismometer. Clipped waveforms are typically assumed not useful and seldom used in waveform-based research. Here, we assume the clipped components of the waveform share the same frequency content with the un-clipped components. We leverage this similarity to convert clipped waveforms to true waveforms by iteratively reconstructing the frequency spectrum using the projection onto convex sets method. Using artificially clipped data we find that statistically the restoration error is ~1% and ~5% when clipped at 70% and 40% peak amplitude, respectively. We verify our method using real data recorded at co-located seismometers that have different gain controls, one set to record large amplitudes on scale and the other set to record low amplitudes on scale. Using our restoration method we recover 87 out of 93 clipped broadband records from the 2013 Mw6.6 Lushan earthquake. Estimating that we recover 20 clipped waveforms for each M5.0+ earthquake, so for the ~1,500 M5.0+ events that occur each year we could restore ~30,000 clipped waveforms each year, which would greatly enhance useable waveform data archives. These restored waveform data would also improve the azimuthal station coverage and spatial footprint.

  1. Restoration of clipped seismic waveforms using projection onto convex sets method

    PubMed Central

    Zhang, Jinhai; Hao, Jinlai; Zhao, Xu; Wang, Shuqin; Zhao, Lianfeng; Wang, Weimin; Yao, Zhenxing

    2016-01-01

    The seismic waveforms would be clipped when the amplitude exceeds the upper-limit dynamic range of seismometer. Clipped waveforms are typically assumed not useful and seldom used in waveform-based research. Here, we assume the clipped components of the waveform share the same frequency content with the un-clipped components. We leverage this similarity to convert clipped waveforms to true waveforms by iteratively reconstructing the frequency spectrum using the projection onto convex sets method. Using artificially clipped data we find that statistically the restoration error is ~1% and ~5% when clipped at 70% and 40% peak amplitude, respectively. We verify our method using real data recorded at co-located seismometers that have different gain controls, one set to record large amplitudes on scale and the other set to record low amplitudes on scale. Using our restoration method we recover 87 out of 93 clipped broadband records from the 2013 Mw6.6 Lushan earthquake. Estimating that we recover 20 clipped waveforms for each M5.0+ earthquake, so for the ~1,500 M5.0+ events that occur each year we could restore ~30,000 clipped waveforms each year, which would greatly enhance useable waveform data archives. These restored waveform data would also improve the azimuthal station coverage and spatial footprint. PMID:27966618

  2. Restoration of clipped seismic waveforms using projection onto convex sets method.

    PubMed

    Zhang, Jinhai; Hao, Jinlai; Zhao, Xu; Wang, Shuqin; Zhao, Lianfeng; Wang, Weimin; Yao, Zhenxing

    2016-12-14

    The seismic waveforms would be clipped when the amplitude exceeds the upper-limit dynamic range of seismometer. Clipped waveforms are typically assumed not useful and seldom used in waveform-based research. Here, we assume the clipped components of the waveform share the same frequency content with the un-clipped components. We leverage this similarity to convert clipped waveforms to true waveforms by iteratively reconstructing the frequency spectrum using the projection onto convex sets method. Using artificially clipped data we find that statistically the restoration error is ~1% and ~5% when clipped at 70% and 40% peak amplitude, respectively. We verify our method using real data recorded at co-located seismometers that have different gain controls, one set to record large amplitudes on scale and the other set to record low amplitudes on scale. Using our restoration method we recover 87 out of 93 clipped broadband records from the 2013 Mw6.6 Lushan earthquake. Estimating that we recover 20 clipped waveforms for each M5.0+ earthquake, so for the ~1,500 M5.0+ events that occur each year we could restore ~30,000 clipped waveforms each year, which would greatly enhance useable waveform data archives. These restored waveform data would also improve the azimuthal station coverage and spatial footprint.

  3. 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.

  4. Convergence of the gradient projection method and Newton's method as applied to optimization problems constrained by intersection of a spherical surface and a convex closed set

    NASA Astrophysics Data System (ADS)

    Chernyaev, Yu. A.

    2016-10-01

    The gradient projection method and Newton's method are generalized to the case of nonconvex constraint sets representing the set-theoretic intersection of a spherical surface with a convex closed set. Necessary extremum conditions are examined, and the convergence of the methods is analyzed.

  5. 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

  6. A fast and robust level set method for image segmentation using fuzzy clustering and lattice Boltzmann method.

    PubMed

    Balla-Arabé, Souleymane; Gao, Xinbo; Wang, Bin

    2013-06-01

    In the last decades, due to the development of the parallel programming, the lattice Boltzmann method (LBM) has attracted much attention as a fast alternative approach for solving partial differential equations. In this paper, we first designed an energy functional based on the fuzzy c-means objective function which incorporates the bias field that accounts for the intensity inhomogeneity of the real-world image. Using the gradient descent method, we obtained the corresponding level set equation from which we deduce a fuzzy external force for the LBM solver based on the model by Zhao. The method is fast, robust against noise, independent to the position of the initial contour, effective in the presence of intensity inhomogeneity, highly parallelizable and can detect objects with or without edges. Experiments on medical and real-world images demonstrate the performance of the proposed method in terms of speed and efficiency.

  7. A set of parallel, implicit methods for a reconstructed discontinuous Galerkin method for compressible flows on 3D hybrid grids

    SciTech Connect

    Xia, Yidong; Luo, Hong; Frisbey, Megan; Nourgaliev, Robert

    2014-07-01

    A set of implicit methods are proposed for a third-order hierarchical WENO reconstructed discontinuous Galerkin method for compressible flows on 3D hybrid grids. An attractive feature in these methods are the application of the Jacobian matrix based on the P1 element approximation, resulting in a huge reduction of memory requirement compared with DG (P2). Also, three approaches -- analytical derivation, divided differencing, and automatic differentiation (AD) are presented to construct the Jacobian matrix respectively, where the AD approach shows the best robustness. A variety of compressible flow problems are computed to demonstrate the fast convergence property of the implemented flow solver. Furthermore, an SPMD (single program, multiple data) programming paradigm based on MPI is proposed to achieve parallelism. The numerical results on complex geometries indicate that this low-storage implicit method can provide a viable and attractive DG solution for complicated flows of practical importance.

  8. A set of parallel, implicit methods for a reconstructed discontinuous Galerkin method for compressible flows on 3D hybrid grids

    DOE PAGES

    Xia, Yidong; Luo, Hong; Frisbey, Megan; ...

    2014-07-01

    A set of implicit methods are proposed for a third-order hierarchical WENO reconstructed discontinuous Galerkin method for compressible flows on 3D hybrid grids. An attractive feature in these methods are the application of the Jacobian matrix based on the P1 element approximation, resulting in a huge reduction of memory requirement compared with DG (P2). Also, three approaches -- analytical derivation, divided differencing, and automatic differentiation (AD) are presented to construct the Jacobian matrix respectively, where the AD approach shows the best robustness. A variety of compressible flow problems are computed to demonstrate the fast convergence property of the implemented flowmore » solver. Furthermore, an SPMD (single program, multiple data) programming paradigm based on MPI is proposed to achieve parallelism. The numerical results on complex geometries indicate that this low-storage implicit method can provide a viable and attractive DG solution for complicated flows of practical importance.« less

  9. 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

  10. 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.

  11. A Mixed Methods Study Identifying Antecedents to the Later Disengagement of African American Males in Public Schools by Examining Attitudes and Behaviors of Students and Teachers at the Elementary School Level

    ERIC Educational Resources Information Center

    Childs, Deirdre L.

    2012-01-01

    African American males have not experienced the academic successes throughout their school careers that males of other cultures have experienced. This mixed methods study identified possible antecedents to the later disengagement of poorly performing African American male students in an inner city public elementary school by examining data…

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Level set immersed boundary method for gas-liquid-solid interactions

    NASA Astrophysics Data System (ADS)

    Wang, Shizhao; Balaras, Elias

    2015-11-01

    We will discuss an approach to simulate the interaction between free surface flows and deformable structures. In our formulation the Navier-Stokes equations are solved on a block-structured grid with adaptive mesh refinement, and the pressure jumps across the interface between different phases, which is tracked using a level set approach, are sharply defined. Deformable structures are simulated with a solid mechanics solver utilizing a finite element method. The overall approach is tailored to problems with large displacement/deformations. The boundary conditions on a solid body are imposed using a direct forcing, immersed boundary method (Vanella & Balaras, J. Comput. Physics, 228(18), 6617-6628, 2009). The flow and structural solvers are coupled by a predictor-corrector, strong-coupling scheme. The consistency between the Eulerian field based level set method for fluid-fluid interface and Lagrangian marker based immersed boundary method for fluid-structure interface is ensured by reconstructing the flow field around the three phase intersections. A variety of 2D and 3D problems ranging from water impact of wedges, entry and exit of cylinders and flexible plates interacting with a free surfaces, are presented to demonstrate the accuracy of the proposed approach. Supported by ONR N000141110588 monitored by Dr. Thomas Fu.

  17. 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.

  18. A novel approach to segmentation and measurement of medical image using level set methods.

    PubMed

    Chen, Yao-Tien

    2017-02-17

    The study proposes a novel approach for segmentation and visualization plus value-added surface area and volume measurements for brain medical image analysis. The proposed method contains edge detection and Bayesian based level set segmentation, surface and volume rendering, and surface area and volume measurements for 3D objects of interest (i.e., brain tumor, brain tissue, or whole brain). Two extensions based on edge detection and Bayesian level set are first used to segment 3D objects. Ray casting and a modified marching cubes algorithm are then adopted to facilitate volume and surface visualization of medical-image dataset. To provide physicians with more useful information for diagnosis, the surface area and volume of an examined 3D object are calculated by the techniques of linear algebra and surface integration. Experiment results are finally reported in terms of 3D object extraction, surface and volume rendering, and surface area and volume measurements for medical image analysis.

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

    NASA Astrophysics Data System (ADS)

    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

    2016-04-01

    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.

  20. 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

  1. 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.

  2. Developing a digital photography-based method for dietary analysis in self-serve dining settings.

    PubMed

    Christoph, Mary J; Loman, Brett R; Ellison, Brenna

    2017-04-01

    Current population-based methods for assessing dietary intake, including food frequency questionnaires, food diaries, and 24-h dietary recall, are limited in their ability to objectively measure food intake. Digital photography has been identified as a promising addition to these techniques but has rarely been assessed in self-serve settings. We utilized digital photography to examine university students' food choices and consumption in a self-serve dining hall setting. Research assistants took pre- and post-photos of students' plates during lunch and dinner to assess selection (presence), servings, and consumption of MyPlate food groups. Four coders rated the same set of approximately 180 meals for inter-rater reliability analyses; approximately 50 additional meals were coded twice by each coder to assess intra-rater agreement. Inter-rater agreement on the selection, servings, and consumption of food groups was high at 93.5%; intra-rater agreement was similarly high with an average of 95.6% agreement. Coders achieved the highest rates of agreement in assessing if a food group was present on the plate (95-99% inter-rater agreement, depending on food group) and estimating the servings of food selected (81-98% inter-rater agreement). Estimating consumption, particularly for items such as beans and cheese that were often in mixed dishes, was more challenging (77-94% inter-rater agreement). Results suggest that the digital photography method presented is feasible for large studies in real-world environments and can provide an objective measure of food selection, servings, and consumption with a high degree of agreement between coders; however, to make accurate claims about the state of dietary intake in all-you-can-eat, self-serve settings, researchers will need to account for the possibility of diners taking multiple trips through the serving line.

  3. Simultaneous segmentation and reconstruction: A level set method approach for limited view computed tomography

    PubMed Central

    Yoon, Sungwon; Pineda, Angel R.; Fahrig, Rebecca

    2010-01-01

    Purpose: An iterative tomographic reconstruction algorithm that simultaneously segments and reconstructs the reconstruction domain is proposed and applied to tomographic reconstructions from a sparse number of projection images. Methods: The proposed algorithm uses a two-phase level set method segmentation in conjunction with an iterative tomographic reconstruction to achieve simultaneous segmentation and reconstruction. The simultaneous segmentation and reconstruction is achieved by alternating between level set function evolutions and per-region intensity value updates. To deal with the limited number of projections, a priori information about the reconstruction is enforced via penalized likelihood function. Specifically, smooth function within each region (piecewise smooth function) and bounded function intensity values for each region are assumed. Such a priori information is formulated into a quadratic objective function with linear bound constraints. The level set function evolutions are achieved by artificially time evolving the level set function in the negative gradient direction; the intensity value updates are achieved by using the gradient projection conjugate gradient algorithm. Results: The proposed simultaneous segmentation and reconstruction results were compared to “conventional” iterative reconstruction (with no segmentation), iterative reconstruction followed by segmentation, and filtered backprojection. Improvements of 6%–13% in the normalized root mean square error were observed when the proposed algorithm was applied to simulated projections of a numerical phantom and to real fan-beam projections of the Catphan phantom, both of which did not satisfy the a priori assumptions. Conclusions: The proposed simultaneous segmentation and reconstruction resulted in improved reconstruction image quality. The algorithm correctly segments the reconstruction space into regions, preserves sharp edges between different regions, and smoothes the noise

  4. Simultaneous segmentation and reconstruction: A level set method approach for limited view computed tomography

    SciTech Connect

    Yoon, Sungwon; Pineda, Angel R.; Fahrig, Rebecca

    2010-05-15

    Purpose: An iterative tomographic reconstruction algorithm that simultaneously segments and reconstructs the reconstruction domain is proposed and applied to tomographic reconstructions from a sparse number of projection images. Methods: The proposed algorithm uses a two-phase level set method segmentation in conjunction with an iterative tomographic reconstruction to achieve simultaneous segmentation and reconstruction. The simultaneous segmentation and reconstruction is achieved by alternating between level set function evolutions and per-region intensity value updates. To deal with the limited number of projections, a priori information about the reconstruction is enforced via penalized likelihood function. Specifically, smooth function within each region (piecewise smooth function) and bounded function intensity values for each region are assumed. Such a priori information is formulated into a quadratic objective function with linear bound constraints. The level set function evolutions are achieved by artificially time evolving the level set function in the negative gradient direction; the intensity value updates are achieved by using the gradient projection conjugate gradient algorithm. Results: The proposed simultaneous segmentation and reconstruction results were compared to ''conventional'' iterative reconstruction (with no segmentation), iterative reconstruction followed by segmentation, and filtered backprojection. Improvements of 6%-13% in the normalized root mean square error were observed when the proposed algorithm was applied to simulated projections of a numerical phantom and to real fan-beam projections of the Catphan phantom, both of which did not satisfy the a priori assumptions. Conclusions: The proposed simultaneous segmentation and reconstruction resulted in improved reconstruction image quality. The algorithm correctly segments the reconstruction space into regions, preserves sharp edges between different regions, and smoothes the noise

  5. 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.

  6. 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.

  7. A Comparison of South African National HIV Incidence Estimates: A Critical Appraisal of Different Methods

    PubMed Central

    Rehle, Thomas; Johnson, Leigh; Hallett, Timothy; Mahy, Mary; Kim, Andrea; Odido, Helen; Onoya, Dorina; Jooste, Sean; Shisana, Olive; Puren, Adrian; Parekh, Bharat; Stover, John

    2015-01-01

    Background The interpretation of HIV prevalence trends is increasingly difficult as antiretroviral treatment programs expand. Reliable HIV incidence estimates are critical to monitoring transmission trends and guiding an effective national response to the epidemic. Methods and Findings We used a range of methods to estimate HIV incidence in South Africa: (i) an incidence testing algorithm applying the Limiting-Antigen Avidity Assay (LAg-Avidity EIA) in combination with antiretroviral drug and HIV viral load testing; (ii) a modelling technique based on the synthetic cohort principle; and (iii) two dynamic mathematical models, the EPP/Spectrum model package and the Thembisa model. Overall, the different incidence estimation methods were in broad agreement on HIV incidence estimates among persons aged 15-49 years in 2012. The assay-based method produced slightly higher estimates of incidence, 1.72% (95% CI 1.38 – 2.06), compared with the mathematical models, 1.47% (95% CI 1.23 – 1.72) in Thembisa and 1.52% (95% CI 1.43 – 1.62) in EPP/Spectrum, and slightly lower estimates of incidence compared to the synthetic cohort, 1.9% (95% CI 0.8 – 3.1) over the period from 2008 to 2012. Among youth aged 15-24 years, a declining trend in HIV incidence was estimated by all three mathematical estimation methods. Conclusions The multi-method comparison showed similar levels and trends in HIV incidence and validated the estimates provided by the assay-based incidence testing algorithm. Our results confirm that South Africa is the country with the largest number of new HIV infections in the world, with about 1 000 new infections occurring each day among adults aged 15-49 years in 2012. PMID:26230949

  8. 3D MR image denoising using rough set and kernel PCA method.

    PubMed

    Phophalia, Ashish; Mitra, Suman K

    2017-02-01

    In this paper, we have presented a two stage method, using kernel principal component analysis (KPCA) and rough set theory (RST), for denoising volumetric MRI data. A rough set theory (RST) based clustering technique has been used for voxel based processing. The method groups similar voxels (3D cubes) using class and edge information derived from noisy input. Each clusters thus formed now represented via basis vector. These vectors now projected into kernel space and PCA is performed in the feature space. This work is motivated by idea that under Rician noise MRI data may be non-linear and kernel mapping will help to define linear separator between these clusters/basis vectors thus used for image denoising. We have further investigated various kernels for Rician noise for different noise levels. The best kernel is then selected on the performance basis over PSNR and structure similarity (SSIM) measures. The work has been compared with state-of-the-art methods under various measures for synthetic and real databases.

  9. Stacking sequence and shape optimization of laminated composite plates via a level-set method

    NASA Astrophysics Data System (ADS)

    Allaire, G.; Delgado, G.

    2016-12-01

    We consider the optimal design of composite laminates by allowing a variable stacking sequence and in-plane shape of each ply. In order to optimize both variables we rely on a decomposition technique which aggregates the constraints into one unique constraint margin function. Thanks to this approach, an exactly equivalent bi-level optimization problem is established. This problem is made up of an inner level represented by the combinatorial optimization of the stacking sequence and an outer level represented by the topology and geometry optimization of each ply. We propose for the stacking sequence optimization an outer approximation method which iteratively solves a set of mixed integer linear problems associated to the evaluation of the constraint margin function. For the topology optimization of each ply, we lean on the level set method for the description of the interfaces and the Hadamard method for boundary variations by means of the computation of the shape gradient. Numerical experiments are performed on an aeronautic test case where the weight is minimized subject to different mechanical constraints, namely compliance, reserve factor and buckling load.

  10. 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

  11. Automatic Four-Chamber Segmentation Using Level-Set Method and Split Energy Function

    PubMed Central

    Kang, Ho Chul; Shin, Juneseuk

    2016-01-01

    Objectives In this paper, we present an automatic method to segment four chambers by extracting a whole heart, separating the left and right sides of the heart, and spliting the atrium and ventricle regions from each heart in cardiac computed tomography angiography (CTA) efficiently. Methods We smooth the images by applying filters to remove noise. Next, the volume of interest is detected by using k-means clustering. In this step, the whole heart is coarsely extracted, and it is used for seed volumes in the next step. Then, we detect seed volumes using a geometric analysis based on anatomical information and separate the left and right heart regions with the power watershed algorithm. Finally, we refine the left and right sides of the heart using the level-set method, and extract the atrium and ventricle from the left and right heart regions using the split energy function. Results We tested the proposed heart segmentation method using 20 clinical scan datasets which were acquired from various patients. To validate the proposed heart segmentation method, we evaluated its accuracy in segmenting four chambers based on four error evaluation metrics. The average values of differences between the manual and automatic segmentations were less than 3.3%, approximately. Conclusions The proposed method extracts the four chambers of the heart accurately, demonstrating that this approach can assist the cardiologist. PMID:27895960

  12. Methods to evaluate health information systems in healthcare settings: a literature review.

    PubMed

    Rahimi, Bahlol; Vimarlund, Vivian

    2007-10-01

    Although information technology (IT)-based applications in healthcare have existed for more than three decades, methods to evaluate outputs and outcomes of the use of IT-based systems in medical informatics is still a challenge for decision makers, as well as to those who want to measure the effects of ICT in healthcare settings. The aim of this paper is to review published articles in the area evaluations of IT-based systems in order to gain knowledge about methodologies used and findings obtained from the evaluation of IT-based systems applied in healthcare settings. The literature review includes studies of IT-based systems between 2003 and 2005. The findings show that economic and organizational aspects dominate evaluation studies in this area. However, the results focus mostly on positive outputs such as user satisfaction, financial benefits and improved organizational work. This review shows that there is no standard framework for evaluation effects and outputs of implementation and use of IT in the healthcare setting and that until today no studies explore the impact of IT on the healthcare system' productivity and effectiveness.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. Numerical simulation of overflow at vertical weirs using a hybrid level set/VOF method

    NASA Astrophysics Data System (ADS)

    Lv, Xin; Zou, Qingping; Reeve, Dominic

    2011-10-01

    This paper presents the applications of a newly developed free surface flow model to the practical, while challenging overflow problems for weirs. Since the model takes advantage of the strengths of both the level set and volume of fluid methods and solves the Navier-Stokes equations on an unstructured mesh, it is capable of resolving the time evolution of very complex vortical motions, air entrainment and pressure variations due to violent deformations following overflow of the weir crest. In the present study, two different types of vertical weir, namely broad-crested and sharp-crested, are considered for validation purposes. The calculated overflow parameters such as pressure head distributions, velocity distributions, and water surface profiles are compared against experimental data as well as numerical results available in literature. A very good quantitative agreement has been obtained. The numerical model, thus, offers a good alternative to traditional experimental methods in the study of weir problems.

  19. 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.

  20. Statistical methods for mapping quantitative trait loci from a dense set of markers.

    PubMed Central

    Dupuis, J; Siegmund, D

    1999-01-01

    Lander and Botstein introduced statistical methods for searching an entire genome for quantitative trait loci (QTL) in experimental organisms, with emphasis on a backcross design and QTL having only additive effects. We extend their results to intercross and other designs, and we compare the power of the resulting test as a function of the magnitude of the additive and dominance effects, the sample size and intermarker distances. We also compare three methods for constructing confidence regions for a QTL: likelihood regions, Bayesian credible sets, and support regions. We show that with an appropriate evaluation of the coverage probability a support region is approximately a confidence region, and we provide a theroretical explanation of the empirical observation that the size of the support region is proportional to the sample size, not the square root of the sample size, as one might expect from standard statistical theory. PMID:9872974

  1. 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.

  2. 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.

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

    PubMed Central

    Moon, Sunjin; Akey, Joshua M.

    2016-01-01

    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. PMID:27197222

  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. Formulation of improved basis sets for the study of polymer dynamics through diffusion theory methods.

    PubMed

    Gaspari, Roberto; Rapallo, Arnaldo

    2008-06-28

    In this work a new method is proposed for the choice of basis functions in diffusion theory (DT) calculations. This method, named hybrid basis approach (HBA), combines the two previously adopted long time sorting procedure (LTSP) and maximum correlation approximation (MCA) techniques; the first emphasizing contributions from the long time dynamics, the latter being based on the local correlations along the chain. In order to fulfill this task, the HBA procedure employs a first order basis set corresponding to a high order MCA one and generates upper order approximations according to LTSP. A test of the method is made first on a melt of cis-1,4-polyisoprene decamers where HBA and LTSP are compared in terms of efficiency. Both convergence properties and numerical stability are improved by the use of the HBA basis set whose performance is evaluated on local dynamics, by computing the correlation times of selected bond vectors along the chain, and on global ones, through the eigenvalues of the diffusion operator L. Further use of the DT with a HBA basis set has been made on a 71-mer of syndiotactic trans-1,2-polypentadiene in toluene solution, whose dynamical properties have been computed with a high order calculation and compared to the "numerical experiment" provided by the molecular dynamics (MD) simulation in explicit solvent. The necessary equilibrium averages have been obtained by a vacuum trajectory of the chain where solvent effects on conformational properties have been reproduced with a proper screening of the nonbonded interactions, corresponding to a definite value of the mean radius of gyration of the polymer in vacuum. Results show a very good agreement between DT calculations and the MD numerical experiment. This suggests a further use of DT methods with the necessary input quantities obtained by the only knowledge of some experimental values, i.e., the mean radius of gyration of the chain and the viscosity of the solution, and by a suitable vacuum

  6. An adaptive multiresolution gradient-augmented level set method for advection problems

    NASA Astrophysics Data System (ADS)

    Schneider, Kai; Kolomenskiy, Dmitry; Nave, Jean-Chtristophe

    2014-11-01

    Advection problems are encountered in many applications, such as transport of passive scalars modeling pollution or mixing in chemical engineering. In some problems, the solution develops small-scale features localized in a part of the computational domain. If the location of these features changes in time, the efficiency of the numerical method can be significantly improved by adapting the partition dynamically to the solution. We present a space-time adaptive scheme for solving advection equations in two space dimensions. The third order accurate gradient-augmented level set method using a semi-Lagrangian formulation with backward time integration is coupled with a point value multiresolution analysis using Hermite interpolation. Thus locally refined dyadic spatial grids are introduced which are efficiently implemented with dynamic quad-tree data structures. For adaptive time integration, an embedded Runge-Kutta method is employed. The precision of the new fully adaptive method is analysed and speed up of CPU time and memory compression with respect to the uniform grid discretization are reported.

  7. 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.

  8. Use of the gamma method for self-contained gene-set analysis of SNP data

    PubMed Central

    Biernacka, Joanna M; Jenkins, Gregory D; Wang, Liewei; Moyer, Ann M; Fridley, Brooke L

    2012-01-01

    Gene-set analysis (GSA) evaluates the overall evidence of association between a phenotype and all genotyped single nucleotide polymorphisms (SNPs) in a set of genes, as opposed to testing for association between a phenotype and each SNP individually. We propose using the Gamma Method (GM) to combine gene-level P-values for assessing the significance of GS association. We performed simulations to compare the GM with several other self-contained GSA strategies, including both one-step and two-step GSA approaches, in a variety of scenarios. We denote a ‘one-step' GSA approach to be one in which all SNPs in a GS are used to derive a test of GS association without consideration of gene-level effects, and a ‘two-step' approach to be one in which all genotyped SNPs in a gene are first used to evaluate association of the phenotype with all measured variation in the gene and then the gene-level tests of association are aggregated to assess the GS association with the phenotype. The simulations suggest that, overall, two-step methods provide higher power than one-step approaches and that combining gene-level P-values using the GM with a soft truncation threshold between 0.05 and 0.20 is a powerful approach for conducting GSA, relative to the competing approaches assessed. We also applied all of the considered GSA methods to data from a pharmacogenomic study of cisplatin, and obtained evidence suggesting that the glutathione metabolism GS is associated with cisplatin drug response. PMID:22166939

  9. 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.

  10. Breast mass segmentation on dynamic contrast-enhanced magnetic resonance scans using the level set method

    NASA Astrophysics Data System (ADS)

    Shi, Jiazheng; Sahiner, Berkman; Chan, Heang-Ping; Paramagul, Chintana; Hadjiiski, Lubomir M.; Helvie, Mark; Wu, Yi-Ta; Ge, Jun; Zhang, Yiheng; Zhou, Chuan; Wei, Jun

    2008-03-01

    The goal of this study was to develop an automated method to segment breast masses on dynamic contrast-enhanced (DCE) magnetic resonance (MR) scans that were performed to monitor breast cancer response to neoadjuvant chemotherapy. A radiologist experienced in interpreting breast MR scans defined the mass using a cuboid volume of interest (VOI). Our method then used the K-means clustering algorithm followed by morphological operations for initial mass segmentation on the VOI. The initial segmentation was then refined by a three-dimensional level set (LS) method. The velocity field of the LS method was formulated in terms of the mean curvature which guaranteed the smoothness of the surface and the Sobel edge information which attracted the zero LS to the desired mass margin. We also designed a method to reduce segmentation leak by adapting a region growing technique. Our method was evaluated on twenty DCE-MR scans of ten patients who underwent neoadjuvant chemotherapy. Each patient had pre- and post-chemotherapy DCE-MR scans on a 1.5 Tesla magnet. Computer segmentation was applied to coronal T1-weighted images. The in-plane pixel size ranged from 0.546 to 0.703 mm and the slice thickness ranged from 2.5 to 4.0 mm. The flip angle was 15 degrees, repetition time ranged from 5.98 to 6.7 ms, and echo time ranged from 1.2 to 1.3 ms. The computer segmentation results were compared to the radiologist's manual segmentation in terms of the overlap measure defined as the ratio of the intersection of the computer and the radiologist's segmentations to the radiologist's segmentation. Pre- and post-chemotherapy masses had overlap measures of 0.81+/-0.11 (mean+/-s.d.) and 0.70+/-0.21, respectively.

  11. 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

  12. Determinants of the accuracy of rapid diagnostic tests in malaria case management: evidence from low and moderate transmission settings in the East African highlands

    PubMed Central

    Abeku, Tarekegn A; Kristan, Mojca; Jones, Caroline; Beard, James; Mueller, Dirk H; Okia, Michael; Rapuoda, Beth; Greenwood, Brian; Cox, Jonathan

    2008-01-01

    Background The accuracy of malaria diagnosis has received renewed interest in recent years due to changes in treatment policies in favour of relatively high-cost artemisinin-based combination therapies. The use of rapid diagnostic tests (RDTs) based on histidine-rich protein 2 (HRP2) synthesized by Plasmodium falciparum has been widely advocated to save costs and to minimize inappropriate treatment of non-malarial febrile illnesses. HRP2-based RDTs are highly sensitive and stable; however, their specificity is a cause for concern, particularly in areas of intense malaria transmission due to persistence of HRP2 antigens from previous infections. Methods In this study, 78,454 clinically diagnosed malaria patients were tested using HRP2-based RDTs over a period of approximately four years in four highland sites in Kenya and Uganda representing hypoendemic to mesoendemic settings. In addition, the utility of the tests was evaluated in comparison with expert microscopy for disease management in 2,241 subjects in two sites with different endemicity levels over four months. Results RDT positivity rates varied by season and year, indicating temporal changes in accuracy of clinical diagnosis. Compared to expert microscopy, the sensitivity, specificity, positive predictive value and negative predictive value of the RDTs in a hypoendemic site were 90.0%, 99.9%, 90.0% and 99.9%, respectively. Corresponding measures at a mesoendemic site were 91.0%, 65.0%, 71.6% and 88.1%. Although sensitivities at the two sites were broadly comparable, levels of specificity varied considerably between the sites as well as according to month of test, age of patient, and presence or absence of fever during consultation. Specificity was relatively high in older age groups and increased towards the end of the transmission season, indicating the role played by anti-HRP2 antibodies. Patients with high parasite densities were more likely to test positive with RDTs than those with low density

  13. Modelling of two-phase flow in a minichannel using level-set method

    NASA Astrophysics Data System (ADS)

    Grzybowski, H.; Mosdorf, R.

    2014-08-01

    Today there is a great interest in micro-scale multiphase fluid flow. In the paper, the numerical simulation of two-phase flow inside 3 mm minichannel was carried out. The liquid- gas interface was captured using the level-set method. During the calculation, the stabilization and reinitialization of level set function was performed in order to obtain the proper accuracy of the simulation. Incompressible Navier-Stokes equations were solved using the COMSOL Multiphysics® on a two-dimensional mesh. The process of formation of different two-phase flow patterns in the minichannel has been investigated. During the simulation it has been analysed three flow patterns: the bubbly flow and two kinds of slug flow with short and long slugs. It has been shown that unsteady flow at the inlet of the minichannel is responsible for the chaotic character of changes of the slug and bubble sizes. Such unsteady flow modifies the distance between the bubbles and slugs. It has been shown that for the low water inlet velocity the two-phase flow pattern becomes more stable.

  14. 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.

  15. 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.

  16. Redefining Racial Residential Segregation and its Association With Physical Activity Among African Americans 50 years and Older: A Mixed Methods Approach

    PubMed Central

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

    2016-01-01

    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. PMID:24812201

  17. Acute rheumatic fever and rheumatic heart disease in resource-limited settings.

    PubMed

    Watson, Gabriella; Jallow, Bintou; Le Doare, Kirsty; Pushparajah, Kuberan; Anderson, Suzanne T

    2015-04-01

    Poststreptococcal complications, such as acute rheumatic fever (ARF) and rheumatic heart disease (RHD), are common in resource-limited settings, with RHD recognised as the most common cause of paediatric heart disease worldwide. Managing these conditions in resource-limited settings can be challenging. We review the investigation and treatment options for ARF and RHD and, most importantly, prevention methods in an African setting.

  18. A Smartphone-Based Genotyping Method for Hepatitis B Virus at Point-of-Care Settings.

    PubMed

    Jiang, Huiqin; Wu, Di; Song, Liuwei; Yuan, Quan; Ge, Shengxiang; Min, Xiaoping; Xia, Ningshao; Qian, Shizhi; Qiu, Xianbo

    2017-04-01

    We reported a rapid, convenient, and easy-to-use genotyping method for hepatitis B virus (HBV) based on the smartphone at point-of-care (POC) settings. To perform HBV genotyping especially for genotypes A, B, C, and D, a smartphone is used to image and analyze a one-step immunoassay lateral flow strip functionalized with genotype-specific monoclonal antibodies (mAbs) on multiple capture lines. A light-emitting diode (LED) positioned on the top of the lateral flow strip is used to shine the multiple capture lines for excitation. Fluorescence detection is obtained with a smartphone whose camera is used to take the fluorescent images. An intelligent algorithm is developed to first identify each capture line from the fluorescent image and then determine the HBV genotype based on a genotyping model. Based on the pattern of the detection signal from different samples, a custom HBV genotyping model is developed. Custom application software running on a smartphone is developed with Java to collect and analyze the fluorescent image, display the genotyping result, and transmit it if necessary. Compared with the existing methods with nucleic acid analysis, more convenient, instant, and efficient HBV genotyping with significantly lower cost and a simpler procedure can be obtained with the developed smartphone POC HBV genotyping method.

  19. A Fréchet derivative-free cubically convergent method for set-valued maps

    NASA Astrophysics Data System (ADS)

    Argyros, Ioannis; Hilout, Saïd

    2008-08-01

    We introduce a new iterative method in order to approximate a locally unique solution of variational inclusions in Banach spaces. The method uses only divided differences operators of order one. An existence-convergence theorem and a radius of convergence are given under some conditions on divided difference operator and Lipschitz-like continuity property of set-valued mappings. Our method extends the recent work related to the resolution of nonlinear equation in Argyros (J Math Anal Appl 332:97-108, 2007) and has the following advantages: faster convergence to the solution than all the previous known ones in Argyros and Hilout (Appl Math Comput, 2008 in press), Hilout (J Math Anal Appl 339:53-761, 2008, Positivity 10:673-700, 2006), and we do not need to evaluate any Fréchet derivative. We provide also an improvement of the ratio of our algorithm under some center-conditions and less computational cost. Numerical examples are also provided.

  20. 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.

  1. 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.

  2. Topology Optimization using the Level Set and eXtended Finite Element Methods: Theory and Applications

    NASA Astrophysics Data System (ADS)

    Villanueva Perez, Carlos Hernan

    Computational design optimization provides designers with automated techniques to develop novel and non-intuitive optimal designs. Topology optimization is a design optimization technique that allows for the evolution of a broad variety of geometries in the optimization process. Traditional density-based topology optimization methods often lack a sufficient resolution of the geometry and physical response, which prevents direct use of the optimized design in manufacturing and the accurate modeling of the physical response of boundary conditions. The goal of this thesis is to introduce a unified topology optimization framework that uses the Level Set Method (LSM) to describe the design geometry and the eXtended Finite Element Method (XFEM) to solve the governing equations and measure the performance of the design. The methodology is presented as an alternative to density-based optimization approaches, and is able to accommodate a broad range of engineering design problems. The framework presents state-of-the-art methods for immersed boundary techniques to stabilize the systems of equations and enforce the boundary conditions, and is studied with applications in 2D and 3D linear elastic structures, incompressible flow, and energy and species transport problems to test the robustness and the characteristics of the method. A comparison of the framework against density-based topology optimization approaches is studied with regards to convergence, performance, and the capability to manufacture the designs. Furthermore, the ability to control the shape of the design to operate within manufacturing constraints is developed and studied. The analysis capability of the framework is validated quantitatively through comparison against previous benchmark studies, and qualitatively through its application to topology optimization problems. The design optimization problems converge to intuitive designs and resembled well the results from previous 2D or density-based studies.

  3. Progress and gaps in reproductive health services in three humanitarian settings: mixed-methods case studies

    PubMed Central

    2015-01-01

    Background Reproductive health (RH) care is an essential component of humanitarian response. Women and girls living in humanitarian settings often face high maternal mortality and are vulnerable to unwanted pregnancy, unsafe abortion, and sexual violence. This study explored the availability and quality of, and access barriers to RH services in three humanitarian settings in Burkina Faso, Democratic Republic of the Congo (DRC), and South Sudan. Methods Data collection was conducted between July and October 2013. In total, 63 purposively selected health facilities were assessed: 28 in Burkina Faso, 25 in DRC, and nine in South Sudan, and 42 providers completed a questionnaire to assess RH knowledge and attitudes. Thirty-four focus group discussions were conducted with 29 members of the host communities and 273 displaced married and unmarried women and men to understand access barriers. Results All facilities reported providing some RH services in the prior three months. Five health facilities in Burkina Faso, six in DRC, and none in South Sudan met the criteria as a family planning service delivery point. Two health facilities in Burkina Faso, one in DRC, and two in South Sudan met the criteria as an emergency obstetric and newborn care service delivery point. Across settings, three facilities in DRC adequately provided selected elements of clinical management of rape. Safe abortion was unavailable. Many providers lacked essential knowledge and skills. Focus groups revealed limited knowledge of available RH services and socio-cultural barriers to accessing them, although participants reported a remarkable increase in use of facility-based delivery services. Conclusion Although RH services are being provided, the availability of good quality RH services was inconsistent across settings. Commodity management and security must be prioritized to ensure consistent availability of essential supplies. It is critical to improve the attitudes, managerial and technical

  4. 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.

  5. Impact of benchmark data set topology on the validation of virtual screening methods: exploration and quantification by spatial statistics.

    PubMed

    Rohrer, Sebastian G; Baumann, Knut

    2008-04-01

    A common finding of many reports evaluating ligand-based virtual screening methods is that validation results vary considerably with changing benchmark data sets. It is widely assumed that these data set specific effects are caused by the redundancy, self-similarity, and cluster structure inherent to those data sets. These phenomena manifest themselves in the data sets' representation in descriptor space, which is termed the data set topology. A methodology for the characterization of data set topology based on spatial statistics is introduced. The method is nonparametric and can deal with arbitrary distributions of descriptor values. With this methodology it is possible to associate differences in virtual screening performance on different data sets with differences in data set topology. Moreover, the better virtual screening performance of certain descriptors can be explained by their ability of representing the benchmark data sets by a more favorable topology. Finally it is shown, that the composition of some benchmark data sets causes topologies that lead to overoptimistic validation results even in very "simple" descriptor spaces. Spatial statistics analysis as proposed here facilitates the detection of such biased data sets and may provide a tool for the future design of unbiased benchmark data sets.

  6. Racial and Gender Differences in Kin Support: A Mixed-Methods Study of African American and Hispanic Couples

    ERIC Educational Resources Information Center

    Haxton, Clarisse L.; Harknett, Kristen

    2009-01-01

    This article uses qualitative and quantitative data for a recent birth cohort from the Fragile Families and Child Wellbeing study to compare kin support patterns between African Americans and Hispanics. It focuses on financial and housing support from grandparents and other kin during the transition to parenthood. Qualitative analysis (n = 122…

  7. Analyzing Planck and low redshift data sets with advanced statistical methods

    NASA Astrophysics Data System (ADS)

    Eifler, Tim

    The recent ESA/NASA Planck mission has provided a key data set to constrain cosmology that is most sensitive to physics of the early Universe, such as inflation and primordial NonGaussianity (Planck 2015 results XIII). In combination with cosmological probes of the LargeScale Structure (LSS), the Planck data set is a powerful source of information to investigate late time phenomena (Planck 2015 results XIV), e.g. the accelerated expansion of the Universe, the impact of baryonic physics on the growth of structure, and the alignment of galaxies in their dark matter halos. It is the main objective of this proposal to re-analyze the archival Planck data, 1) with different, more recently developed statistical methods for cosmological parameter inference, and 2) to combine Planck and ground-based observations in an innovative way. We will make the corresponding analysis framework publicly available and believe that it will set a new standard for future CMB-LSS analyses. Advanced statistical methods, such as the Gibbs sampler (Jewell et al 2004, Wandelt et al 2004) have been critical in the analysis of Planck data. More recently, Approximate Bayesian Computation (ABC, see Weyant et al 2012, Akeret et al 2015, Ishida et al 2015, for cosmological applications) has matured to an interesting tool in cosmological likelihood analyses. It circumvents several assumptions that enter the standard Planck (and most LSS) likelihood analyses, most importantly, the assumption that the functional form of the likelihood of the CMB observables is a multivariate Gaussian. Beyond applying new statistical methods to Planck data in order to cross-check and validate existing constraints, we plan to combine Planck and DES data in a new and innovative way and run multi-probe likelihood analyses of CMB and LSS observables. The complexity of multiprobe likelihood analyses scale (non-linearly) with the level of correlations amongst the individual probes that are included. For the multi

  8. 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

  9. Emerging analytical methods to determine gluten markers in processed foods--method development in support of standard setting.

    PubMed

    Weber, Dorcas; Cléroux, Chantal; Godefroy, Samuel Benrejeb

    2009-09-01

    The availability of analytical methods to detect and determine levels of markers of priority allergens in foods is of the utmost importance to support standard setting initiatives, the development of compliance and enforcement activities, as well as to provide guidance to industry on implementation of quality control practices, ensuring the effectiveness of allergen-related sanitation techniques. This paper describes the development and implementation of a mass-spectrometry-based technique to determine markers for individual sources of gluten in beer products. This methodology was shown to answer the requirements of Health Canada's proposed labeling standard for individual gluten source declaration, in order to achieve its policy objectives (i.e., protection of sensitive consumers, while promoting choice). Minimal sample work-up was required and the results obtained by ELISA were further complemented using the LC-MS/MS method. This paper aims to demonstrate the feasibility of alternative techniques to ELISA-based methodologies to determine allergen and gluten markers in food.

  10. 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.

  11. Comparing volume of fluid and level set methods for evaporating liquid-gas flows

    NASA Astrophysics Data System (ADS)

    Palmore, John; Desjardins, Olivier

    2016-11-01

    This presentation demonstrates three numerical strategies for simulating liquid-gas flows undergoing evaporation. The practical aim of this work is to choose a framework capable of simulating the combustion of liquid fuels in an internal combustion engine. Each framework is analyzed with respect to its accuracy and computational cost. All simulations are performed using a conservative, finite volume code for simulating reacting, multiphase flows under the low-Mach assumption. The strategies used in this study correspond to different methods for tracking the liquid-gas interface and handling the transport of the discontinuous momentum and vapor mass fractions fields. The first two strategies are based on conservative, geometric volume of fluid schemes using directionally split and un-split advection, respectively. The third strategy is the accurate conservative level set method. For all strategies, special attention is given to ensuring the consistency between the fluxes of mass, momentum, and vapor fractions. The study performs three-dimensional simulations of an isolated droplet of a single component fuel evaporating into air. Evaporation rates and vapor mass fractions are compared to analytical results.

  12. 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.

  13. 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

  14. 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.

  15. 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…

  16. An abdominal aortic aneurysm segmentation method: level set with region and statistical information.

    PubMed

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

    2006-05-01

    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 +/- 2.3 mm (s.d.); worst case = 9.6 mm, respectively. When implemented on a 2.8 GHz Pentium IV personal computer, the mean time required for segmentation was 7.4 +/- 3.6 min (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.

  17. 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.

  18. 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.

  19. What are Hospice Providers in the Carolinas Doing to Reach African Americans in Their Service Area?

    PubMed Central

    Payne, Richard; Kuchibhatla, Maragatha N.

    2016-01-01

    Abstract Background: Experts and national organizations recommend that hospices work to increase service to African Americans, a group historically underrepresented in hospice. Objective: The study objective was to describe strategies among hospices in North and South Carolina to increase service to African Americans and identify hospice characteristics associated with these efforts. Methods: The study was a cross-sectional survey using investigator-developed scales to measure frequency of community education/outreach, directed marketing, efforts to recruit African American staff, cultural sensitivity training, and goals to increase service to African Americans. We used nonparametric Wilcoxon tests to compare mean scale scores by sample characteristics. Results: Of 118 eligible hospices, 79 (67%) completed the survey. Over 80% were at least somewhat concerned about the low proportion of African Americans they served, and 78.5% had set goals to increase service to African Americans. Most were engaged in community education/outreach, with 92.4% reporting outreach to churches, 76.0% to social services organizations, 40.5% to businesses, 35.4% to civic groups, and over half to health care providers; 48.0% reported directed marketing via newspaper and 40.5% via radio. The vast majority reported efforts to recruit African American staff, most often registered nurses (63.75%). Nearly 90% offered cultural sensitivity training to staff. The frequency of strategies to increase service to African Americans did not vary by hospice characteristics, such as profit status, size, or vertical integration, but was greater among hospices that had set goals to increase service to African Americans. Conclusions: Many hospices are engaged in efforts to increase service to African Americans. Future research should determine which strategies are most effective. PMID:26840854

  20. 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

  1. 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.

  2. Narcolepsy in African Americans

    PubMed Central

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

    2015-01-01

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

  3. 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

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Wessel, P.

    2011-12-01

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

  6. 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.

  7. Integrating spatial fuzzy clustering with level set methods for automated medical image segmentation.

    PubMed

    Li, Bing Nan; Chui, Chee Kong; Chang, Stephen; Ong, S H

    2011-01-01

    The performance of the level set segmentation is subject to appropriate initialization and optimal configuration of controlling parameters, which require substantial manual intervention. A new fuzzy level set algorithm is proposed in this paper to facilitate medical image segmentation. It is able to directly evolve from the initial segmentation by spatial fuzzy clustering. The controlling parameters of level set evolution are also estimated from the results of fuzzy clustering. Moreover the fuzzy level set algorithm is enhanced with locally regularized evolution. Such improvements facilitate level set manipulation and lead to more robust segmentation. Performance evaluation of the proposed algorithm was carried on medical images from different modalities. The results confirm its effectiveness for medical image segmentation.

  8. Explaining household socio-economic related child health inequalities using multiple methods in three diverse settings in South Africa

    PubMed Central

    2011-01-01

    Background Despite free healthcare to pregnant women and children under the age of six, access to healthcare has failed to secure better child health outcomes amongst all children of the country. There is growing evidence of socioeconomic gradient on child health outcomes Methods The objectives of this study were to measure inequalities in child mortality, HIV transmission and vaccination coverage within a cohort of infants in South Africa. We also used the decomposition technique to identify the factors that contribute to the inequalities in these three child health outcomes. We used data from a prospective cohort study of mother-child pairs in three sites in South African. A relative index of household socio-economic status was developed using principal component analysis. This paper uses the concentration index to summarise inequalities in child mortality, HIV transmission and vaccination coverage. Results We observed disparities in the availability of infrastructure between least poor and most poor families, and inequalities in all measured child health outcomes. Overall, 75 (8.5%) infants died between birth and 36 weeks. Infant mortality and HIV transmission was higher among the poorest families within the sample. Immunisation coverage was higher among the least poor. The inequalities were mainly due to the area of residence and socio-economic position. Conclusion This study provides evidence that socio-economic inequalities are highly prevalent within the relatively poor black population. Poor socio-economic position exposes infants to ill health. In addition, the use of immunisation services was lower in the poor households. These inequalities need to be explicitly addressed in future programme planning to improve child health for all South Africans. PMID:21463530

  9. The set of photoelectromagnetic methods for determination of recombination and diffusion parameters of p-MCT thin films

    NASA Astrophysics Data System (ADS)

    Protasov, D. Y.; Trifanov, A. V.; Kostyuchenko, V. Y.

    2013-06-01

    In this paper the set of photoelectromagnetic methods for determination of recombination and diffusion parameters of charge carriers in p-type mercury cadmium telluride epitaxial thin films at temperature range 77-125 K is offered. The set of methods includes the photoconductivity in magnetic field for Faraday and Voigt geometries, the photoelectromagnetic effect, the Hall effect and the measurements of magnetoconductivity. Such films parameters as concentrations and mobilities of heavy and light holes, mobility of minor electrons, electrons lifetime and ratio between holes and electrons lifetimes, surface recombination velocities can be determined with help of offered set.

  10. 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.

  11. 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

  12. On some methods for improving time of reachability sets computation for the dynamic system control problem

    NASA Astrophysics Data System (ADS)

    Zimovets, Artem; Matviychuk, Alexander; Ushakov, Vladimir

    2016-12-01

    The paper presents two different approaches to reduce the time of computer calculation of reachability sets. First of these two approaches use different data structures for storing the reachability sets in the computer memory for calculation in single-threaded mode. Second approach is based on using parallel algorithms with reference to the data structures from the first approach. Within the framework of this paper parallel algorithm of approximate reachability set calculation on computer with SMP-architecture is proposed. The results of numerical modelling are presented in the form of tables which demonstrate high efficiency of parallel computing technology and also show how computing time depends on the used data structure.

  13. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

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

  14. Alternative method of Reduction of the Feynman Diagrams to a set of Master Integrals

    NASA Astrophysics Data System (ADS)

    Borja, Julio; Kondrashuk, Igor

    2016-10-01

    We propose a new set of Master Integrals which can be used as a basis for certain multiloop calculations in massless gauge field theories. In these theories we consider three-point Feynman diagrams with arbitrary number of loops. The corresponding multiloop integrals may be decomposed in terms of this set of the Master Integrals. We construct a new reduction procedure which we apply to perform this decomposition.

  15. 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.

  16. 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

  17. 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.

  18. Extension of the Mass-Conserving Level-Set method to unstructured polyhedral control volumes for two-phase flows

    NASA Astrophysics Data System (ADS)

    Raees, Fahim; van der Heul, Duncan R.; Vuik, Kees

    2013-11-01

    In this research, we present the Mass-Conserving Level-Set method (MCLS) for the simulation of two-dimensional, incompressible, immiscible two-phase flows, using a discretisation scheme that can accurately and efficiently handle domains of arbitrary geometrical complexity. The level set and the volume of fluid fraction are evolved at each time step on unstructured triangular grids. The Higher-Order Discontinuous Galerkin finite element method is used for spatial discretisation of the level set advection equation. The volume of fluid fraction advection is done in geometrical manner using Lagrangian-Eulerian method. This method is accurately mass conserving and easy to implement on unstructured grids. Also, it avoids overlapping regions during the volume of fluid fraction advection. The advected level set is corrected locally to make it mass conserving by the means of an explicit, invertible relation between the local level set and the volume of fluid fraction. This relation is termed as a Volume-of-Fluid function. The results show that proposed method is accurately mass conserving. Also, higher-order convergence is highlighted with this method on unstructured grids for the different test cases.

  19. Effects of the Drop-set and Reverse Drop-set Methods on the Muscle Activity and Intramuscular Oxygenation of the Triceps Brachii among Trained and Untrained Individuals

    PubMed Central

    Goto, Masahiro; Nirengi, Shinsuke; Kurosawa, Yuko; Nagano, Akinori; Hamaoka, Takafumi

    2016-01-01

    Influence of different load exercise to muscle activity during subsequent exercise with 75% of one repetition maximum (RM) load among trained and untrained individuals was verified. Resistance-trained men who were involved in resistance training (n = 16) and healthy young men who did not exercise regularly (n = 16) were recruited for this study. Each subject performed bench pressing with a narrow grip exercise using two different training set methods, the drop-set (DS) (3 sets × 2-10 repetitions with 95-75% of 1RM) and the reverse drop-set (RDS) (3 sets × 3-10 repetitions with 55-75% of 1RM). The mean concentric contraction power, root mean square (RMS) of electromyography (EMG), area under the oxygenated hemoglobin (Oxy-Hb) curve, and time constant for muscle oxygen consumption (TcVO2mus) values of the triceps brachii were measured during and after the DS and RDS. The trained group demonstrated significantly higher mean muscle power (242.9 ± 39.6 W vs. 215.8 ± 31.7 W), RMS of EMG (86.4 ± 10.4 % vs. 68.3 ± 9.6 %), and area under the Oxy-Hb curve (38.6 ± 7.4 %• sec vs. 29.3 ± 5.8 %• sec) values during the DS than during the RDS (p < 0.05). However, in the untrained group none of the parameters differed significantly for both the DS and RDS. Furthermore, a negative correlation was detected between the area under the Oxy-Hb curve and muscle thickness (r = -0.51, p < 0.01). Long-term effects of DS on muscle strengthening and hypertrophy will be explored in further research. Key points The DS induced greater motor unit activation and intramuscular hypoxia in people who have been regularly performing resistance exercises for more than one year than the RDS. No mechanical or metabolic differences were detected between the DS and RDS among the subjects who had not participated in regular resistance training. The thicker a person’s muscles are, the more resistant they are to the induction of acute intramuscular hypoxia during muscle contraction. PMID:27928200

  20. ‘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

  1. 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.…

  2. A novel region-based level set method initialized with mean shift clustering for automated medical image segmentation.

    PubMed

    Bai, Pei Rui; Liu, Qing Yi; Li, Lei; Teng, Sheng Hua; Li, Jing; Cao, Mao Yong

    2013-11-01

    Appropriate initialization and stable evolution are desirable criteria to satisfy in level set methods. In this study, a novel region-based level set method utilizing both global and local image information complementarily is proposed. The global image information is extracted from mean shift clustering without any prior knowledge. Appropriate initial contours are obtained by regulating the clustering results. The local image information, as extracted by a data fitting energy, is employed to maintain a stable evolution of the zero level set curves. The advantages of the proposed method are as follows. First, the controlling parameters of the evolution can be easily estimated by the clustering results. Second, the automaticity of the model increases because of a reduction in computational cost and manual intervention. Experimental results confirm the efficiency and accuracy of the proposed method for medical image segmentation.

  3. Impact of anthropogenic and climatic changes on biomass and diversity of the Central African forests, from local to global scale: original methods for new results

    NASA Astrophysics Data System (ADS)

    Mortier, Frédéric; Gourlet-Fleury, Sylvie; Ouédraogo, Dakis; Picard, Nicolas; Rossi, Vivien

    2014-05-01

    Forests of the Congo Basin, the second most important remaining block of tropical moist forest in the world, are facing increasing anthropogenic pressure and climate change. Understanding the biomass and diversity dynamics under these pressures is one major challenge for African nations and international communities. This talk aims to present original methods to model, infer, and predict growth, biomass and diversity of Central African forests, as well as new results on the impacts of global change on those forests, at various scales. With respect to methods, we will present theoretical frameworks allowing (i) to model growth processes in species-rich ecosystems like tropical rain forests, (ii) to take into account uncertainties in biomass estimation. In terms of results, we will highlight at a local scale, how human activities as well as climatic variations would impact (i) the composition and diversity of forests, (ii) the dynamics of biomass and growth processes. At a global scale, we will demonstrate how environmental filtering controls the above ground biomass. The number of studies are currently increasing over the Congo Basin through several research projects led by our team (CoForTips, DynAfFor) and contributing to various international organization's programs (Cifor, FAO, Comifac, Ofac).

  4. Terrestrial Water Storage in African Hydrological Regimes Derived from GRACE Mission Data: Intercomparison of Spherical Harmonics, Mass Concentration, and Scalar Slepian Methods.

    PubMed

    Rateb, Ashraf; Kuo, Chung-Yen; Imani, Moslem; Tseng, Kuo-Hsin; Lan, Wen-Hau; Ching, Kuo-En; Tseng, Tzu-Pang

    2017-03-10

    Spherical harmonics (SH) and mascon solutions are the two most common types of solutions for Gravity Recovery and Climate Experiment (GRACE) mass flux observations. However, SH signals are degraded by measurement and leakage errors. Mascon solutions (the Jet Propulsion Laboratory (JPL) release, herein) exhibit weakened signals at submascon resolutions. Both solutions require a scale factor examined by the CLM4.0 model to obtain the actual water storage signal. The Slepian localization method can avoid the SH leakage errors when applied to the basin scale. In this study, we estimate SH errors and scale factors for African hydrological regimes. Then, terrestrial water storage (TWS) in Africa is determined based on Slepian localization and compared with JPL-mascon and SH solutions. The three TWS estimates show good agreement for the TWS of large-sized and humid regimes but present discrepancies for the TWS of medium and small-sized regimes. Slepian localization is an effective method for deriving the TWS of arid zones. The TWS behavior in African regimes and its spatiotemporal variations are then examined. The negative TWS trends in the lower Nile and Sahara at -1.08 and -6.92 Gt/year, respectively, are higher than those previously reported.

  5. Terrestrial Water Storage in African Hydrological Regimes Derived from GRACE Mission Data: Intercomparison of Spherical Harmonics, Mass Concentration, and Scalar Slepian Methods

    PubMed Central

    Rateb, Ashraf; Kuo, Chung-Yen; Imani, Moslem; Tseng, Kuo-Hsin; Lan, Wen-Hau; Ching, Kuo-En; Tseng, Tzu-Pang

    2017-01-01

    Spherical harmonics (SH) and mascon solutions are the two most common types of solutions for Gravity Recovery and Climate Experiment (GRACE) mass flux observations. However, SH signals are degraded by measurement and leakage errors. Mascon solutions (the Jet Propulsion Laboratory (JPL) release, herein) exhibit weakened signals at submascon resolutions. Both solutions require a scale factor examined by the CLM4.0 model to obtain the actual water storage signal. The Slepian localization method can avoid the SH leakage errors when applied to the basin scale. In this study, we estimate SH errors and scale factors for African hydrological regimes. Then, terrestrial water storage (TWS) in Africa is determined based on Slepian localization and compared with JPL-mascon and SH solutions. The three TWS estimates show good agreement for the TWS of large-sized and humid regimes but present discrepancies for the TWS of medium and small-sized regimes. Slepian localization is an effective method for deriving the TWS of arid zones. The TWS behavior in African regimes and its spatiotemporal variations are then examined. The negative TWS trends in the lower Nile and Sahara at −1.08 and −6.92 Gt/year, respectively, are higher than those previously reported. PMID:28287453

  6. African-American Biography.

    ERIC Educational Resources Information Center

    Martin, Ron

    1995-01-01

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

  7. 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.

  8. A Benchmark Test Set for Alchemical Free Energy Transformations and Its Use to Quantify Error in Common Free Energy Methods.

    PubMed

    Paliwal, Himanshu; Shirts, Michael R

    2011-12-13

    There is a significant need for improved tools to validate thermophysical quantities computed via molecular simulation. In this paper we present the initial version of a benchmark set of testing methods for calculating free energies of molecular transformation in solution. This set is based on molecular changes common to many molecular design problems, such as insertion and deletion of atomic sites and changing atomic partial charges. We use this benchmark set to compare the statistical efficiency, reliability, and quality of uncertainty estimates for a number of published free energy methods, including thermodynamic integration, free energy perturbation, the Bennett acceptance ratio (BAR) and its multistate equivalent MBAR. We identify MBAR as the consistently best performing method, though other methods are frequently comparable in reliability and accuracy in many cases. We demonstrate that assumptions of Gaussian distributed errors in free energies are usually valid for most methods studied. We demonstrate that bootstrap error estimation is a robust and useful technique for estimating statistical variance for all free energy methods studied. This benchmark set is provided in a number of different file formats with the hope of becoming a useful and general tool for method comparisons.

  9. The Use of Subsets of Test Questions in an Angoff Standard Setting Method.

    ERIC Educational Resources Information Center

    Ferdous, Abdullah; Plake, Barbara

    In the Angoff standard setting procedure, subject matter experts (SMEs) estimate the probability that a hypothetical randomly selected minimally competent candidate will answer correctly each item comprising the test. In many cases, these item performance estimates are made twice, with information shared with SMEs between estimates. This…

  10. A Review of Functional Analysis Methods Conducted in Public School Classroom Settings

    ERIC Educational Resources Information Center

    Lloyd, Blair P.; Weaver, Emily S.; Staubitz, Johanna L.

    2016-01-01

    The use of functional behavior assessments (FBAs) to address problem behavior in classroom settings has increased as a result of education legislation and long-standing evidence supporting function-based interventions. Although functional analysis remains the standard for identifying behavior--environment functional relations, this component is…

  11. Examining Rounding Rules in Angoff-Type Standard-Setting Methods

    ERIC Educational Resources Information Center

    Wyse, Adam E.; Reckase, Mark D.

    2012-01-01

    This study investigates how different rounding rules and ways of providing Angoff standard-setting judgments affect cut-scores. A simulation design based on data from the National Assessment of Education Progress was used to investigate how rounding judgments to the nearest whole number (e.g., 0, 1, 2, etc.), nearest 0.05, or nearest two decimal…

  12. African Trypanosomiasis

    DTIC Science & Technology

    2011-06-01

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

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

    PubMed

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

    2010-10-01

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

  14. The expanded FindCore method for identification of a core atom set for assessment of protein structure prediction.

    PubMed

    Snyder, David A; Grullon, Jennifer; Huang, Yuanpeng J; Tejero, Roberto; Montelione, Gaetano T

    2014-02-01

    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 (Snyder and 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.

  15. First-principle modelling of forsterite surface properties: Accuracy of methods and basis sets.

    PubMed

    Demichelis, Raffaella; Bruno, Marco; Massaro, Francesco R; Prencipe, Mauro; De La Pierre, Marco; Nestola, Fabrizio

    2015-07-15

    The seven main crystal surfaces of forsterite (Mg2 SiO4 ) were modeled using various Gaussian-type basis sets, and several formulations for the exchange-correlation functional within the density functional theory (DFT). The recently developed pob-TZVP basis set provides the best results for all properties that are strongly dependent on the accuracy of the wavefunction. Convergence on the structure and on the basis set superposition error-corrected surface energy can be reached also with poorer basis sets. The effect of adopting different DFT functionals was assessed. All functionals give the same stability order for the various surfaces. Surfaces do not exhibit any major structural differences when optimized with different functionals, except for higher energy orientations where major rearrangements occur around the Mg sites at the surface or subsurface. When dispersions are not accounted for, all functionals provide similar surface energies. The inclusion of empirical dispersions raises the energy of all surfaces by a nearly systematic value proportional to the scaling factor s of the dispersion formulation. An estimation for the surface energy is provided through adopting C6 coefficients that are more suitable than the standard ones to describe O-O interactions in minerals. A 2 × 2 supercell of the most stable surface (010) was optimized. No surface reconstruction was observed. The resulting structure and surface energy show no difference with respect to those obtained when using the primitive cell. This result validates the (010) surface model here adopted, that will serve as a reference for future studies on adsorption and reactivity of water and carbon dioxide at this interface.

  16. 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

  17. It Takes a Village: A Mixed Method Analysis of Inner Setting Variables and Dialectical Behavior Therapy Implementation.

    PubMed

    Ditty, Matthew S; Landes, Sara J; Doyle, Andrea; Beidas, Rinad S

    2015-11-01

    Guided by the Consolidated Framework for Implementation Research, 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.

  18. 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.

  19. Standardized method to quantify the variation in voxel value distribution in patient-simulated CBCT data sets

    PubMed Central

    Gotfredsen, E; Wenzel, A

    2015-01-01

    Objectives: To suggest a standardized method to assess the variation in voxel value distribution in patient-simulated CBCT data sets and the effect of time between exposures (TBE). Additionally, a measurement of reproducibility, Aarhus measurement of reproducibility (AMORe), is introduced, which could be used for quality assurance purposes. Methods: Six CBCT units were tested [Cranex® 3D/CRAN (Soredex Oy, Tuusula, Finland); Scanora® 3D/SCAN (Soredex Oy); NewTom™ 5G/NEW5 (QR srl, Verona, Italy); i-CAT/ICAT (Imaging Sciences International, Hatfield, PA); 3D Accuitomo FPD80/ACCU (Morita, Kyoto, Japan); and NewTom VG/NEWV (QR srl)]. Two sets of volumetric data of a wax-imbedded dry human skull (containing a titanium implant) were acquired by each CBCT unit at two sessions on separate days. Each session consisted 21 exposures: 1 “initial” followed by a 30-min interval (initial data set), 10 acquired with 30-min TBE (data sets 1–10) and 10 acquired with 15-min TBE (data sets 11–20). CBCT data were exported as digital imaging and communications in medicine files and converted to text files containing x, y and z positions and grey shade for each voxel. Subtractions were performed voxel-by-voxel in two set-ups: (1) between two consecutive data sets and (2) between any subsequent data set and data set 1. The mean grey shade variation for each voxel was calculated for each unit/session. Results: The largest mean grey shade variation was found in the subtraction set-up 2 (27–447 shades of grey, depending on the unit). Considering subtraction set-up 1, the highest variation was seen for NEW5, between data sets 1 and the initial. Conclusions: Discrepancies in voxel value distribution were found by comparing the initial examination of the day with the subsequent examinations. TBE had no predictable effect on the variation of CBCT-derived voxel values. AMORe ranged between 0 and 64. PMID:25354021

  20. Accurate dispersion interactions from standard density-functional theory methods with small basis sets.

    PubMed

    Mackie, Iain D; Dilabio, Gino A

    2010-06-21

    B971, PBE and PBE1 density functionals with 6-31G(d) basis sets are shown to accurately describe the binding in dispersion bound dimers. This is achieved through the use of dispersion-correcting potentials (DCPs) in conjunction with counterpoise corrections. DCPs resemble and are applied like conventional effective core potentials that can be used with most computational chemistry programs without code modification. Rather, DCPs are implemented by simple appendage to the input files for these types of programs. Binding energies are predicted to within ca. 11% and monomer separations to within ca. 0.06 A of high-level wavefunction data using B971/6-31G(d)-DCP. Similar results are obtained for PBE and PBE1 with the 6-31G(d) basis sets and DCPs. Although results found using the 3-21G(d) are not as impressive, they never-the-less show promise as a means of initial study for a wide variety of dimers, including those dominated by dispersion, hydrogen-bonding and a mixture of interactions. Notable improvement is found in comparison to M06-2X/6-31G(d) data, e.g., mean absolute deviations for the S22-set of dimers of ca. 13.6 and 16.5% for B971/6-31G(d)-DCP and M06-2X, respectively. However, it should be pointed out that the latter data were obtained using a larger integration grid size since a smaller grid results in different binding energies and geometries for simple dispersion-bound dimers such as methane and ethene.

  1. 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/.

  2. The Television Framing Methods of the National Basketball Association: An Agenda-Setting Application.

    ERIC Educational Resources Information Center

    Fortunato, John A.

    2001-01-01

    Identifies and analyzes the exposure and portrayal framing methods that are utilized by the National Basketball Association (NBA). Notes that key informant interviews provide insight into the exposure framing method and reveal two portrayal instruments: cameras and announcers; and three framing strategies: depicting the NBA as a team game,…

  3. 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 ...

  4. 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...

  5. 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…

  6. Comparison of methods of alert acknowledgement by critical care clinicians in the ICU setting

    PubMed Central

    Harrison, Andrew M.; Thongprayoon, Charat; Aakre, Christopher A.; Jeng, Jack Y.; Dziadzko, Mikhail A.; Gajic, Ognjen; Pickering, Brian W.

    2017-01-01

    Background Electronic Health Record (EHR)-based sepsis alert systems have failed to demonstrate improvements in clinically meaningful endpoints. However, the effect of implementation barriers on the success of new sepsis alert systems is rarely explored. Objective To test the hypothesis time to severe sepsis alert acknowledgement by critical care clinicians in the ICU setting would be reduced using an EHR-based alert acknowledgement system compared to a text paging-based system. Study Design In one arm of this simulation study, real alerts for patients in the medical ICU were delivered to critical care clinicians through the EHR. In the other arm, simulated alerts were delivered through text paging. The primary outcome was time to alert acknowledgement. The secondary outcomes were a structured, mixed quantitative/qualitative survey and informal group interview. Results The alert acknowledgement rate from the severe sepsis alert system was 3% (N = 148) and 51% (N = 156) from simulated severe sepsis alerts through traditional text paging. Time to alert acknowledgement from the severe sepsis alert system was median 274 min (N = 5) and median 2 min (N = 80) from text paging. The response rate from the EHR-based alert system was insufficient to compare primary measures. However, secondary measures revealed important barriers. Conclusion Alert fatigue, interruption, human error, and information overload are barriers to alert and simulation studies in the ICU setting. PMID:28316887

  7. 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…

  8. Methods for Incorporating Patient Preferences for Treatments of Depression in Community Mental Health Settings.

    PubMed

    Crits-Christoph, Paul; Gallop, Robert; Diehl, Caroline K; Yin, Seohyun; Gibbons, Mary Beth Connolly

    2016-06-22

    We developed three methods (rating, ranking, and discrete choice) for identifying patients' preferred depression treatments based on their prioritization of specific treatment attributes (e.g., medication side effects, psychotherapy characteristics) at treatment intake. Community mental health patients with depressive symptoms participated in separate studies of predictive validity (N = 193) and short-term (1-week) stability (N = 40). Patients who received non-preferred initial treatments (based on the choice method) switched treatments significantly more often than those who received preferred initial treatments. Receiving a non-preferred treatment at any point (based on rating and choice methods) was a significant predictor of longer treatment duration. All three methods demonstrated good short-term stability.

  9. An easy and reliable automated method to estimate oxidative stress in the clinical setting.

    PubMed

    Vassalle, Cristina

    2008-01-01

    During the last few years, reliable and simple tests have been proposed to estimate oxidative stress in vivo. Many of them can be easily adapted to automated analyzers, permitting the simultaneous processing of a large number of samples in a greatly reduced time, avoiding manual sample and reagent handling, and reducing variability sources. In this chapter, description of protocols for the estimation of reactive oxygen metabolites and the antioxidant capacity (respectively the d-ROMs and OXY Adsorbent Test, Diacron, Grosseto, Italy) by using the clinical chemistry analyzer SYNCHRON, CX 9 PRO (Beckman Coulter, Brea, CA, USA) is reported as an example of such an automated procedure that can be applied in the clinical setting. Furthermore, a calculation to compute a global oxidative stress index (Oxidative-INDEX), reflecting both oxidative and antioxidant counterparts, and, therefore, a potentially more powerful parameter, is also described.

  10. 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…

  11. 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:…

  12. 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.

  13. Combining evidence and values in priority setting: testing the balance sheet method in a low-income country

    PubMed Central

    Makundi, Emmanuel; Kapiriri, Lydia; Norheim, Ole Frithjof

    2007-01-01

    Background Procedures for priority setting need to incorporate both scientific evidence and public values. The aim of this study was to test out a model for priority setting which incorporates both scientific evidence and public values, and to explore use of evidence by a selection of stakeholders and to study reasons for the relative ranking of health care interventions in a setting of extreme resource scarcity. Methods Systematic search for and assessment of relevant evidence for priority setting in a low-income country. Development of a balance sheet according to Eddy's explicit method. Eight group interviews (n-85), using a modified nominal group technique for eliciting individual and group rankings of a given set of health interventions. Results The study procedure made it possible to compare the groups' ranking before and after all the evidence was provided to participants. A rank deviation is significant if the rank order of the same intervention differed by two or more points on the ordinal scale. A comparison between the initial rank and the final rank (before deliberation) showed a rank deviation of 67%. The difference between the initial rank and the final rank after discussion and voting gave a rank deviation of 78%. Conclusion Evidence-based and deliberative decision-making does change priorities significantly in an experimental setting. Our use of the balance sheet method was meant as a demonstration project, but could if properly developed be feasible for health planners, experts and health workers, although more work is needed before it can be used for laypersons. PMID:17892561

  14. Defect inspection in hot slab surface: multi-source CCD imaging based fuzzy-rough sets method

    NASA Astrophysics Data System (ADS)

    Zhao, Liming; Zhang, Yi; Xu, Xiaodong; Xiao, Hong; Huang, Chao

    2016-09-01

    To provide an accurate surface defects inspection method and make the automation of robust image region of interests(ROI) delineation strategy a reality in production line, a multi-source CCD imaging based fuzzy-rough sets method is proposed for hot slab surface quality assessment. The applicability of the presented method and the devised system are mainly tied to the surface quality inspection for strip, billet and slab surface etcetera. In this work we take into account the complementary advantages in two common machine vision (MV) systems(line array CCD traditional scanning imaging (LS-imaging) and area array CCD laser three-dimensional (3D) scanning imaging (AL-imaging)), and through establishing the model of fuzzy-rough sets in the detection system the seeds for relative fuzzy connectedness(RFC) delineation for ROI can placed adaptively, which introduces the upper and lower approximation sets for RIO definition, and by which the boundary region can be delineated by RFC region competitive classification mechanism. For the first time, a Multi-source CCD imaging based fuzzy-rough sets strategy is attempted for CC-slab surface defects inspection that allows an automatic way of AI algorithms and powerful ROI delineation strategies to be applied to the MV inspection field.

  15. 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.

  16. 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.

  17. A new method for the level set equation using a hierarchical-gradient truncation and remapping technique

    NASA Astrophysics Data System (ADS)

    Kohno, Haruhiko; Nave, Jean-Christophe

    2013-06-01

    We present a novel numerical method for solving the advection equation for a level set function. The new method uses hierarchical-gradient truncation and remapping (H-GTaR) of the original partial differential equation (PDE). Our strategy reduces the original PDE to a set of decoupled linear ordinary differential equations with constant coefficients. Additionally, we introduce a remapping strategy to periodically guarantee solution accuracy for a deformation problem. The proposed scheme yields nearly an exact solution for a rigid body motion with a smooth function that possesses vanishingly small higher derivatives and calculates the gradient of the advected function in a straightforward way. We will evaluate our method in one- and two-dimensional domains and present results to several classical benchmark problems.

  18. 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

  19. 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

  20. 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

  1. 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…

  2. A comparison of the oral and silent reading methods of standardized science test delivery on the performance level of fifth-grade African American students

    NASA Astrophysics Data System (ADS)

    Merenda, Gloria Louise

    This study compared two methods of standardized test administration, oral delivery using an audio tape and the standard silent reading by the student, on the performance level (test score) and science understanding (right answer/right reason) of urban fifth grade African American students. The effect of reading ability, special needs, and socioeconomic status were also examined as possible confounding variables. A randomized post-test only control group design was used with data for the sample (N = 106) collected from student files at two Detroit Public Schools, which included the Michigan Education Assessment Program (MEAP) reading and science scores. In addition, face-to-face interviews were completed with a small subsample to determine reasoning for selecting their answers. Six hypotheses were developed to determine if there were significant differences in science performance level and understanding in fifth grade urban African American students when the standardized science test, MEAP, Area Specific Portions, Physical Science and Earth/Space Science, were delivered orally, using the audio tape, and silently, which is the present standard delivery method. Significant differences in scores were found favoring the oral over the silent test group. A significant association was also found for reading and science MEAP scores, with students who had higher scores on the reading test achieving higher scores on the science test. Although socioeconomic status did not appear to result in differential outcomes among the students, a significant interaction was found between test administration type and socioeconomic status. The conclusion that was reached was that students who have difficulty in reading the printed material could benefit from having standardized tests administered orally (except for reading tests).

  3. Numerical Simulation of Two-phase flow with Phase Change Using the Level-set Method

    NASA Astrophysics Data System (ADS)

    Li, Hongying; Lou, Jing; Pan, Lunsheng; Yap, Yitfatt

    2016-11-01

    Multiphase flow with phase change is widely encountered in many engineering applications. A distinct feature involves in these applications is the phase transition from one phase to another due to the non-uniform temperature distribution. Such kind of process generally releases or absorbs large amount of energy with mass transfer happened simultaneously. It demands great cautions occasionally such as the high pressure due to evaporation. This article presents a numerical model for simulation of two-fluid flow with phase change problem. In these two fluids, one of them changes its state due to phase change. Such a problem then involves two substances with three phases as well as two different interfaces, i.e. the interface between two substances and the interface of one substance between its two phases. Two level-set functions are used to capture the two interfaces in the current problem. The current model is validated against one-dimensional and two-dimensional liquid evaporation. With the code validated, it is applied to different phase change problems including (1) a falling evaporating droplet and the rising of one bubble and (2) two-fluid stratified flow with solidification of one fluid. Comparisons on the bubble and droplet topologies, flow and temperature fields are made for the first case between the falling evaporating droplet and the falling droplet without evaporation. For the second demonstration case, the effect of the superheated temperature on the solidification process is investigated.

  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. 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.

  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. 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.

  8. 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.

  9. 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…

  10. 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…

  11. Partial spectral projected gradient method with active-set strategy for linearly constrained optimization

    NASA Astrophysics Data System (ADS)

    Andretta, Marina; Birgin, Ernesto; Martínez, J.

    2010-01-01

    A method for linearly constrained optimization which modifies and generalizes recent box-constraint optimization algorithms is introduced. The new algorithm is based on a relaxed form of Spectral Projected Gradient iterations. Intercalated with these projected steps, internal iterations restricted to faces of the polytope are performed, which enhance the efficiency of the algorithm. Convergence proofs are given and numerical experiments are included and commented. Software supporting this paper is available through the Tango Project web page: http://www.ime.usp.br/˜egbirgin/tango/.

  12. 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.

  13. 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.

  14. Uncertainty quantification through the Monte Carlo method in a cloud computing setting

    NASA Astrophysics Data System (ADS)

    Cunha, Americo; Nasser, Rafael; Sampaio, Rubens; Lopes, Hélio; Breitman, Karin

    2014-05-01

    The Monte Carlo (MC) method is the most common technique used for uncertainty quantification, due to its simplicity and good statistical results. However, its computational cost is extremely high, and, in many cases, prohibitive. Fortunately, the MC algorithm is easily parallelizable, which allows its use in simulations where the computation of a single realization is very costly. This work presents a methodology for the parallelization of the MC method, in the context of cloud computing. This strategy is based on the MapReduce paradigm, and allows an efficient distribution of tasks in the cloud. This methodology is illustrated on a problem of structural dynamics that is subject to uncertainties. The results show that the technique is capable of producing good results concerning statistical moments of low order. It is shown that even a simple problem may require many realizations for convergence of histograms, which makes the cloud computing strategy very attractive (due to its high scalability capacity and low-cost). Additionally, the results regarding the time of processing and storage space usage allow one to qualify this new methodology as a solution for simulations that require a number of MC realizations beyond the standard.

  15. Joint use of TEM and MRS methods in a complex geological setting

    NASA Astrophysics Data System (ADS)

    Legchenko, Anatoly; Ezersky, Michael; Camerlynck, Christian; Al-Zoubi, Abdallah; Chalikakis, Konstantinos

    2009-10-01

    Transient Electromagnetic (TEM), known also as Time Domain Electromagnetic (TDEM) and Magnetic Resonance Sounding (MRS) methods were applied jointly to investigate variations in lithology and groundwater salinity in the Nahal Hever South area (Dead Sea coast of Israel). The subsurface in this area is highly heterogeneous and composed of intercalated sand and clay layers over a salt formation, which is partly karstified. Groundwater is very saline, with a chloride concentration of 100-225 g/l. TEM is known as an efficient tool for investigating electrically conductive targets like saline water, but it is sensitive to both the salinity of groundwater and the porosity of rocks. MRS, however, is sensitive primarily to groundwater volume, but it also allows delineating of lithological variations in water-saturated formations. MRS is much less sensitive to variations in groundwater salinity in comparison with TEM. We show that MRS enables us to resolve the fundamental uncertainty in TEM interpretation caused by the equivalence between groundwater resistivity and lithology. Combining TEM and MRS, we found that the sandy Dead Sea aquifer filled with Dead Sea brine is characterized by a bulk resistivity of ρx > 0.4 Ωm, whereas zones with silt and clay in the subsurface are characterized by a bulk resistivity of ρx < 0.4 Ωm. These observations are confirmed by calibration of the TEM method performed near 18 boreholes.

  16. Gradient Augmented Level Set Method for Two Phase Flow Simulations with Phase Change

    NASA Astrophysics Data System (ADS)

    Anumolu, C. R. Lakshman; Trujillo, Mario F.

    2016-11-01

    A sharp interface capturing approach is presented for two-phase flow simulations with phase change. The Gradient Augmented Levelset method is coupled with the two-phase momentum and energy equations to advect the liquid-gas interface and predict heat transfer with phase change. The Ghost Fluid Method (GFM) is adopted for velocity to discretize the advection and diffusion terms in the interfacial region. Furthermore, the GFM is employed to treat the discontinuity in the stress tensor, velocity, and temperature gradient yielding an accurate treatment in handling jump conditions. Thermal convection and diffusion terms are approximated by explicitly identifying the interface location, resulting in a sharp treatment for the energy solution. This sharp treatment is extended to estimate the interfacial mass transfer rate. At the computational cell, a d-cubic Hermite interpolating polynomial is employed to describe the interface location, which is locally fourth-order accurate. This extent of subgrid level description provides an accurate methodology for treating various interfacial processes with a high degree of sharpness. The ability to predict the interface and temperature evolutions accurately is illustrated by comparing numerical results with existing 1D to 3D analytical solutions.

  17. 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).

  18. 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…

  19. 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.

  20. Comparison of image segmentation of lungs using methods: connected threshold, neighborhood connected, and threshold level set segmentation

    NASA Astrophysics Data System (ADS)

    Amanda, A. R.; Widita, R.

    2016-03-01

    The aim of this research is to compare some image segmentation methods for lungs based on performance evaluation parameter (Mean Square Error (MSE) and Peak Signal Noise to Ratio (PSNR)). In this study, the methods compared were connected threshold, neighborhood connected, and the threshold level set segmentation on the image of the lungs. These three methods require one important parameter, i.e the threshold. The threshold interval was obtained from the histogram of the original image. The software used to segment the image here was InsightToolkit-4.7.0 (ITK). This research used 5 lung images to be analyzed. Then, the results were compared using the performance evaluation parameter determined by using MATLAB. The segmentation method is said to have a good quality if it has the smallest MSE value and the highest PSNR. The results show that four sample images match the criteria of connected threshold, while one sample refers to the threshold level set segmentation. Therefore, it can be concluded that connected threshold method is better than the other two methods for these cases.

  1. 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.

  2. Set up an Arc Welding Code with Enthalpy Method in Upwind Scheme

    NASA Astrophysics Data System (ADS)

    Ho, Je-Ee.

    2010-05-01

    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.

  3. Systematic testing of Gaussian and complete basis set methods with dispersion corrections for environmentally relevant clusters

    NASA Astrophysics Data System (ADS)

    Lemke, Kono H.

    2014-11-01

    Results are presented demonstrating the ability of CBS-x and Gn theory to predict energies for non-covalently bound complexes, both uncorrected and upon implementation of dispersion-sensitive DFT. CBS-QCI/APNO performs best among uncorrected methods (MUE 0.88 kcal mol-1), while G4 (MUE 1.05 kcal mol-1) and CBS-QB3 (MUE 1.13 kcal mol-1) provide energies close to that of CBS-QCI/APNO, but at a reduced cost. Inclusion of B2PLYP-D and B97-D as well as M0N-2X type functionals into G4 and CBS-QB3 results in improved binding energies. From a comparison with CCSD(T)/CBS results, M05-2X/CBS-QB3 structures and binding energies provide a cost-effective and accurate description of environmentally relevant non-covalent interactions.

  4. Level Set Methods for Optimization Problems Involving Geometry and Constraints. I. Frequencies of a Two-Density Inhomogeneous Drum

    NASA Astrophysics Data System (ADS)

    Osher, Stanley J.; Santosa, Fadil

    2001-07-01

    Many problems in engineering design involve optimizing the geometry to maximize a certain design objective. Geometrical constraints are often imposed. In this paper, we use the level set method devised in (Osher and Sethian, J. Comput. Phys.79, 12 (1988)), the variational level set calculus presented in (Zhao et al., J. Comput. Phys.127, 179 (1996)), and the projected gradient method, as in (Rudin et al., Physica D.60, 259 (1992)), to construct a simple numerical approach for problems of this type. We apply this technique to a model problem involving a vibrating system whose resonant frequency or whose spectral gap is to be optimized subject to constraints on geometry. Our numerical results are quite promising. We expect to use this approach to deal with a wide class of optimal design problems in the future.

  5. Comparison of combinatorial clustering methods on pharmacological data sets represented by machine learning-selected real molecular descriptors.

    PubMed

    Rivera-Borroto, Oscar Miguel; Marrero-Ponce, Yovani; García-de la Vega, José Manuel; Grau-Ábalo, Ricardo del Corazón

    2011-12-27

    Cluster algorithms play an important role in diversity related tasks of modern chemoinformatics, with the widest applications being in pharmaceutical industry drug discovery programs. The performance of these grouping strategies depends on various factors such as molecular representation, mathematical method, algorithmical technique, and statistical distribution of data. For this reason, introduction and comparison of new methods are necessary in order to find the model that best fits the problem at hand. Earlier comparative studies report on Ward's algorithm using fingerprints for molecular description as generally superior in this field. However, problems still remain, i.e., other types of numerical descriptions have been little exploited, current descriptors selection strategy is trial and error-driven, and no previous comparative studies considering a broader domain of the combinatorial methods in grouping chemoinformatic data sets have been conducted. In this work, a comparison between combinatorial methods is performed,with five of them being novel in cheminformatics. The experiments are carried out using eight data sets that are well established and validated in the medical chemistry literature. Each drug data set was represented by real molecular descriptors selected by machine learning techniques, which are consistent with the neighborhood principle. Statistical analysis of the results demonstrates that pharmacological activities of the eight data sets can be modeled with a few of families with 2D and 3D molecular descriptors, avoiding classification problems associated with the presence of nonrelevant features. Three out of five of the proposed cluster algorithms show superior performance over most classical algorithms and are similar (or slightly superior in the most optimistic sense) to Ward's algorithm. The usefulness of these algorithms is also assessed in a comparative experiment to potent QSAR and machine learning classifiers, where they perform

  6. Method and basis set dependence of anharmonic ground state nuclear wave functions and zero-point energies: application to SSSH.

    PubMed

    Kolmann, Stephen J; Jordan, Meredith J T

    2010-02-07

    One of the largest remaining errors in thermochemical calculations is the determination of the zero-point energy (ZPE). The fully coupled, anharmonic ZPE and ground state nuclear wave function of the SSSH radical are calculated using quantum diffusion Monte Carlo on interpolated potential energy surfaces (PESs) constructed using a variety of method and basis set combinations. The ZPE of SSSH, which is approximately 29 kJ mol(-1) at the CCSD(T)/6-31G* level of theory, has a 4 kJ mol(-1) dependence on the treatment of electron correlation. The anharmonic ZPEs are consistently 0.3 kJ mol(-1) lower in energy than the harmonic ZPEs calculated at the Hartree-Fock and MP2 levels of theory, and 0.7 kJ mol(-1) lower in energy at the CCSD(T)/6-31G* level of theory. Ideally, for sub-kJ mol(-1) thermochemical accuracy, ZPEs should be calculated using correlated methods with as big a basis set as practicable. The ground state nuclear wave function of SSSH also has significant method and basis set dependence. The analysis of the nuclear wave function indicates that SSSH is localized to a single symmetry equivalent global minimum, despite having sufficient ZPE to be delocalized over both minima. As part of this work, modifications to the interpolated PES construction scheme of Collins and co-workers are presented.

  7. 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.

  8. Simplex Free Adaptive Tree Fast Sweeping and Evolution Methods for Solving Level Set Equations in Arbitrary Dimension

    DTIC Science & Technology

    2005-05-06

    and node counts for a codimension-n problem of solving the eikonal equation |∇φ| = 1, (8) with a boundary point at xb = (0.5, 0.5, . . . , 0.5) with...unorganized points using variational level set method. Comp. Vis. and Image Under., 80:295–319, 2000. [40] Hongkai Zhao. A fast sweeping method for eikonal equations. Math. Comp., 74(250):603–627 (electronic), 2005. 21 ...nature. Secondly, they re- quire a backtracking along characteristics and an interpolation at an arbitrary point within the domain. This

  9. 3D Segmentation with an application of level set-method using MRI volumes for image guided surgery.

    PubMed

    Bosnjak, A; Montilla, G; Villegas, R; Jara, I

    2007-01-01

    This paper proposes an innovation in the application for image guided surgery using a comparative study of three different method of segmentation. This segmentation method is faster than the manual segmentation of images, with the advantage that it allows to use the same patient as anatomical reference, which has more precision than a generic atlas. This new methodology for 3D information extraction is based on a processing chain structured of the following modules: 1) 3D Filtering: the purpose is to preserve the contours of the structures and to smooth the homogeneous areas; several filters were tested and finally an anisotropic diffusion filter was used. 2) 3D Segmentation. This module compares three different methods: Region growing Algorithm, Cubic spline hand assisted, and Level Set Method. It then proposes a Level Set-based on the front propagation method that allows the making of the reconstruction of the internal walls of the anatomical structures of the brain. 3) 3D visualization. The new contribution of this work consists on the visualization of the segmented model and its use in the pre-surgery planning.

  10. 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.

  11. Evaluation of the micro-CATT, CATT/Trypanosoma brucei gambiense, and LATEX/T b gambiense methods for serodiagnosis and surveillance of human African trypanosomiasis in West and Central Africa.

    PubMed Central

    Truc, Philippe; Lejon, Veerle; Magnus, Eddy; Jamonneau, Vincent; Nangouma, Auguste; Verloo, Didier; Penchenier, Laurent; Büscher, Philippe

    2002-01-01

    OBJECTIVE: To evaluate the performance of serological tests using dried blood on filter-papers (micro-card agglutination test for trypanosomiasis (micro-CATT)) performed under field and laboratory conditions and using whole blood ((CATT/T.b. gambiense) (wb-CATT) and latex agglutination (LATEX/T.b. gambiense) (wb-LATEX)) for the serodiagnosis and surveillance of human African trypanosomiasis in West and Central Africa. METHODS: We evaluated the micro-CATT, wb-CATT and wb-LATEX methods in Côte d'Ivoire and the Central African Republic by screening 940 people. Sensitivity and specificity were calculated for each serological test; only patients with the confirmed presence of trypanosomes in the blood or lymph aspirate were considered true positives. Positive and negative predictive values were also calculated. FINDINGS: Each of the tests showed a lower sensitivity in the Central African Republic than in Côte d'Ivoire. CONCLUSION: The results confirmed the efficiency of the classic wb-CATT to detect sleeping sickness patients. The micro-CATT method can be used for human African trypanosomiasis surveillance if the test is performed on the same day as the blood collection, or if samples are stored at 4 degrees C. Otherwise, micro-CATT can be used when absolute sensitivity is not required. wb-LATEX should only be used for high-specificity screening. PMID:12481210

  12. 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.

  13. 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

  14. Data mining of the GAW14 simulated data using rough set theory and tree-based methods.

    PubMed

    Wei, Liang-Ying; Huang, Cheng-Lung; Chen, Chien-Hsiun

    2005-12-30

    Rough set theory and decision trees are data mining methods used for dealing with vagueness and uncertainty. They have been utilized to unearth hidden patterns in complicated datasets collected for industrial processes. The Genetic Analysis Workshop 14 simulated data were generated using a system that implemented multiple correlations among four consequential layers of genetic data (disease-related loci, endophenotypes, phenotypes, and one disease trait). When information of one layer was blocked and uncertainty was created in the correlations among these layers, the correlation between the first and last layers (susceptibility genes and the disease trait in this case), was not easily directly detected. In this study, we proposed a two-stage process that applied rough set theory and decision trees to identify genes susceptible to the disease trait. During the first stage, based on phenotypes of subjects and their parents, decision trees were built to predict trait values. Phenotypes retained in the decision trees were then advanced to the second stage, where rough set theory was applied to discover the minimal subsets of genes associated with the disease trait. For comparison, decision trees were also constructed to map susceptible genes during the second stage. Our results showed that the decision trees of the first stage had accuracy rates of about 99% in predicting the disease trait. The decision trees and rough set theory failed to identify the true disease-related loci.

  15. 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.

  16. 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…

  17. Barriers to Hospice Use among African Americans: A Systematic Review

    ERIC Educational Resources Information Center

    Washington, Karla T.; Bickel-Swenson, Denise; Stephens, Nathan

    2008-01-01

    The present review was undertaken to explore recent evidence in the professional literature pertaining to use of hospice services by African Americans. The article addresses the research methods that have been used to study African American hospice use, obstacles to African American participation in hospice that have been identified, and…

  18. 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.

  19. Method for deriving the complete solution set for three-mirror anastigmatic telescopes with two spherical mirrors.

    PubMed

    Rakich, Andrew; Rumsey, Norman

    2002-07-01

    The "plate-diagram" method of quantifying and manipulating the Seidel aberrations of an optical system has been used to develop a procedure that has successfully determined the complete solution set of three-mirror anastigmats in which two surfaces are left strictly spherical. The procedure also readily identified solutions in which the Petzval sum is zero, and four distinct families of flat-field three-mirror anastigmats with two mirrors strictly spherical have thus been found. The success of the method is strong support for the argument that algebraic approaches to optical design can yield results distinctly superior to currently favored optimization-based design methods, at least for some types of optical systems.

  20. Comparison of different statistical methods for estimation of extreme sea levels with wave set-up contribution

    NASA Astrophysics Data System (ADS)

    Kergadallan, Xavier; Bernardara, Pietro; Benoit, Michel; Andreewsky, Marc; Weiss, Jérôme

    2013-04-01

    Estimating the probability of occurrence of extreme sea levels is a central issue for the protection of the coast. Return periods of sea level with wave set-up contribution are estimated here in one site : Cherbourg in France in the English Channel. The methodology follows two steps : the first one is computation of joint probability of simultaneous wave height and still sea level, the second one is interpretation of that joint probabilities to assess a sea level for a given return period. Two different approaches were evaluated to compute joint probability of simultaneous wave height and still sea level : the first one is multivariate extreme values distributions of logistic type in which all components of the variables become large simultaneously, the second one is conditional approach for multivariate extreme values in which only one component of the variables have to be large. Two different methods were applied to estimate sea level with wave set-up contribution for a given return period : Monte-Carlo simulation in which estimation is more accurate but needs higher calculation time and classical ocean engineering design contours of type inverse-FORM in which the method is simpler and allows more complex estimation of wave setup part (wave propagation to the coast for example). We compare results from the two different approaches with the two different methods. To be able to use both Monte-Carlo simulation and design contours methods, wave setup is estimated with an simple empirical formula. We show advantages of the conditional approach compared to the multivariate extreme values approach when extreme sea-level occurs when either surge or wave height is large. We discuss the validity of the ocean engineering design contours method which is an alternative when computation of sea levels is too complex to use Monte-Carlo simulation method.

  1. Factors influencing choices for colorectal cancer screening among previously unscreened African and Caucasian Americans: findings from a triangulation mixed methods investigation.

    PubMed

    Ruffin, Mack T; Creswell, John W; Jimbo, Masahito; Fetters, Michael D

    2009-04-01

    We investigated factors that influence choice of colorectal cancer (CRC) screening test and assessed the most- and least-preferred options among fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, and double contrast barium enema among adults with varied race, gender, and geographic region demographics. Mixed methods data collection consisted of 10 focus group interviews and a survey of the 93 focus group participants. Participants were >or=50 years of age and reported not having been screened for colorectal cancer in the last ten years. Analyses examined differences by race, gender, and geographic location. Participants had modest knowledge about CRC and there were fewer correct answers to knowledge questions by African Americans. Participants recognized value of early detection, and identified health symptoms and their doctor's recommendation as influential for obtaining CRC screening. They chose colonoscopy and FOBT as the most preferred tests, while barium enema was least preferred. The analysis revealed intra-group variations in preference, though there were no significant differences by race, gender, or location. Openness of discussing this sensitive topic, lack of knowledge about colorectal cancer and screening costs, and diversity of preferences expressed within study groups suggest the importance of patient-physician dialogue about colorectal cancer screening options. New approaches to promoting colorectal cancer screening need to explore methods to facilitate patients establishing and expressing preferences among the screening options.

  2. Factors Influencing Choices for Colorectal Cancer Screening Among Previously Unscreened African and Caucasian Americans: Findings from a Triangulation Mixed Methods Investigation

    PubMed Central

    Ruffin, Mack T.; Creswell, John W.; Jimbo, Masahito

    2014-01-01

    We investigated factors that influence choice of colorectal cancer (CRC) screening test and assessed the most- and least-preferred options among fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, and double contrast barium enema among adults with varied race, gender, and geographic region demographics. Mixed methods data collection consisted of 10 focus group interviews and a survey of the 93 focus group participants. Participants were ≥50 years of age and reported not having been screened for colorectal cancer in the last ten years. Analyses examined differences by race, gender, and geographic location. Participants had modest knowledge about CRC and there were fewer correct answers to knowledge questions by African Americans. Participants recognized value of early detection, and identified health symptoms and their doctor's recommendation as influential for obtaining CRC screening. They chose colonoscopy and FOBT as the most preferred tests, while barium enema was least preferred. The analysis revealed intra-group variations in preference, though there were no significant differences by race, gender, or location. Openness of discussing this sensitive topic, lack of knowledge about colorectal cancer and screening costs, and diversity of preferences expressed within study groups suggest the importance of patient-physician dialogue about colorectal cancer screening options. New approaches to promoting colorectal cancer screening need to explore methods to facilitate patients establishing and expressing preferences among the screening options. PMID:19082695

  3. Comparison of two trapping methods for Culicoides biting midges and determination of African horse sickness virus prevalence in midge populations at Onderstepoort, South Africa.

    PubMed

    Scheffer, Elisabeth G; Venter, Gert J; Labuschagne, Karien; Page, Patrick C; Mullens, Bradley A; MacLachlan, N James; Osterrieder, Nikolaus; Guthrie, Alan J

    2012-04-30

    Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of a variety of pathogens including African horse sickness virus (AHSV), a member of the family Reoviridae, genus Orbivirus. AHSV causes African horse sickness (AHS), an endemic disease of equids with an extremely high mortality rate in horses in sub-Saharan Africa. Culicoides (Avaritia) imicola Kieffer is considered to be the principal vector of AHSV and is the dominant Culicoides species in South Africa. Due to the global distribution of Culicoides vectors, there is a potential risk of AHS spreading from endemic areas to areas traditionally free of the disease, which could have a severe economical impact on the affected equine industry. As part of any risk assessment it is essential to monitor known vectors as well as potential vector species. In the present study, sampling of Culicoides insects was compared using overnight collections in the conventional Onderstepoort light trap and mechanical aspiration of midges at sunset from bait horses. Culicoides imicola was confirmed as the predominant species using both trapping methods. Other species, mainly Culicoides (Avaritia) bolitinos Meiswinkel and Culicoides (Avaritia) gulbenkiani Caeiro, were highly underrepresented in the light trap collections, but made a significant contribution to the mechanical aspiration catches. The time for optimal collection differed between the trapping methods, leading to the conclusion that mechanical aspiration is a useful addition to conventional light trap collection and possibly the better choice when investigating insect vectors. An infection rate of 1.14% was calculated for the midge population based on real-time quantitative reverse-transcription polymerase chain reaction (RT-qPCR) assays of collected Culicoides midges, which exceeds previous estimates. This is probably due to the increased sensitivity of the RT-qPCR assay used in this study as compared to the virus isolation assays used in previous studies. RT

  4. A new non-overlapping concept to improve the Hybrid Particle Level Set method in multi-phase fluid flows

    NASA Astrophysics Data System (ADS)

    Archer, Philip J.; Bai, Wei

    2015-02-01

    A novel non-overlapping concept is augmented to the Hybrid Particle Level Set (HPLS) method to improve its accuracy and suitability for the modelling of multi-phase fluid flows. The concept addresses shortcomings in the reseeding algorithm, which maintains resolution of the surface at runtime. These shortcomings result in the misplacement of newly seeded particles in the opposite signed domain and necessitate a restriction on the distance that a particle can escape without deletion, which reduces the effectiveness of the method. The non-overlapping concept judges the suitability of potential new particles based on information already contained within the particle representation of the surface. By preventing the misplacement of particles it is possible to significantly relax the distance restriction thereby increasing the accuracy of the HPLS method in multi-phase flows. To demonstrate its robustness and efficiency, the concept is examined with a number of challenging test cases, including both level-set-only simulations and two-phase fluid flows.

  5. 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.

  6. Challenges in internet study recruitment of African American cancer patients.

    PubMed

    Bender, Melinda; Clark, Maresha; Guevara, Enrique; Chee, Wonshik; Im, Eun-Ok

    2006-01-01

    Health care inequities continue to plague African Americans. For African American cancer patients these inequities include access to health care, availability of treatment modalities, support groups, and participation in nursing cancer research. A support group setting is better for recruitment than a clinical setting. Referrals to the researcher from individuals who personally know the African American cancer patients generated the best response rates. If the researcher has no previous connection with the potential participant, interest in the study may be generated but recruitment is minimal or absent. Ethnically sensitive recruitment of African American cancer patients is therefore essential to improving participatory responses in cancer nursing research.

  7. Nursing Education Interventions for Managing Acute Pain in Hospital Settings: A Systematic Review of Clinical Outcomes and Teaching Methods.

    PubMed

    Drake, Gareth; de C Williams, Amanda C

    2017-02-01

    The objective of this review was to examine the effects of nursing education interventions on clinical outcomes for acute pain management in hospital settings, relating interventions to health care behavior change theory. Three databases were searched for nursing education interventions from 2002 to 2015 in acute hospital settings with clinical outcomes reported. Methodological quality was rated as strong, moderate, or weak using the Effective Public Health Practice Project Quality Assessment Tool for quantitative studies. The 12 eligible studies used varied didactic and interactive teaching methods. Several studies had weaknesses attributable to selection biases, uncontrolled confounders, and lack of blinding of outcome assessors. No studies made reference to behavior change theory in their design. Eight of the 12 studies investigated nursing documentation of pain assessment as the main outcome, with the majority reporting positive effects of education interventions on nursing pain assessment. Of the remaining studies, two reported mixed findings on patient self-report of pain scores as the key measure, one reported improvements in patient satisfaction with pain management after a nursing intervention, and one study found an increase in nurses' delivery of a relaxation treatment following an intervention. Improvements in design and evaluation of nursing education interventions are suggested, drawing on behavior change theory and emphasizing the relational, contextual, and emotionally demanding nature of nursing pain management in hospital settings.

  8. 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

  9. 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.

  10. Barrett's Mucosa Segmentation in Endoscopic Images Using a Hybrid Method: Spatial Fuzzy c-mean and Level Set

    PubMed Central

    Yousefi-Banaem, Hossein; Rabbani, Hossein; Adibi, Peyman

    2016-01-01

    Barrett's mucosa is one of the most important diseases in upper gastrointestinal system that caused by gastro-esophagus reflux. If left untreated, the disease will cause distal esophagus and gastric cardia adenocarcinoma. The malignancy risk is very high in short segment Barrett's mucosa. Therefore, lesion area segmentation can improve specialist decision for treatment. In this paper, we proposed a combined fuzzy method with active models for Barrett's mucosa segmentation. In this study, we applied three methods for special area segmentation and determination. For whole disease area segmentation, we applied the hybrid fuzzy based level set method (LSM). Morphological algorithms were used for gastroesophageal junction determination, and we discriminated Barrett's mucosa from break by applying Chan-Vase method. Fuzzy c-mean and LSMs fail to segment this type of medical image due to weak boundaries. In contrast, the full automatic hybrid method with correlation approach that has used in this paper segmented the metaplasia area in the endoscopy image with desirable accuracy. The presented approach omits the manually desired cluster selection step that needed the operator manipulation. Obtained results convinced us that this approach is suitable for esophagus metaplasia segmentation. PMID:28028499

  11. Barrett's Mucosa Segmentation in Endoscopic Images Using a Hybrid Method: Spatial Fuzzy c-mean and Level Set.

    PubMed

    Yousefi-Banaem, Hossein; Rabbani, Hossein; Adibi, Peyman

    2016-01-01

    Barrett's mucosa is one of the most important diseases in upper gastrointestinal system that caused by gastro-esophagus reflux. If left untreated, the disease will cause distal esophagus and gastric cardia adenocarcinoma. The malignancy risk is very high in short segment Barrett's mucosa. Therefore, lesion area segmentation can improve specialist decision for treatment. In this paper, we proposed a combined fuzzy method with active models for Barrett's mucosa segmentation. In this study, we applied three methods for special area segmentation and determination. For whole disease area segmentation, we applied the hybrid fuzzy based level set method (LSM). Morphological algorithms were used for gastroesophageal junction determination, and we discriminated Barrett's mucosa from break by applying Chan-Vase method. Fuzzy c-mean and LSMs fail to segment this type of medical image due to weak boundaries. In contrast, the full automatic hybrid method with correlation approach that has used in this paper segmented the metaplasia area in the endoscopy image with desirable accuracy. The presented approach omits the manually desired cluster selection step that needed the operator manipulation. Obtained results convinced us that this approach is suitable for esophagus metaplasia segmentation.

  12. Testing Allele Transmission of an SNP Set Using a Family-Based Generalized Genetic Random Field Method.

    PubMed

    Li, Ming; Li, Jingyun; He, Zihuai; Lu, Qing; Witte, John S; Macleod, Stewart L; Hobbs, Charlotte A; Cleves, Mario A

    2016-05-01

    Family-based association studies are commonly used in genetic research because they can be robust to population stratification (PS). Recent advances in high-throughput genotyping technologies have produced a massive amount of genomic data in family-based studies. However, current family-based association tests are mainly focused on evaluating individual variants one at a time. In this article, we introduce a family-based generalized genetic random field (FB-GGRF) method to test the joint association between a set of autosomal SNPs (i.e., single-nucleotide polymorphisms) and disease phenotypes. The proposed method is a natural extension of a recently developed GGRF method for population-based case-control studies. It models offspring genotypes conditional on parental genotypes, and, thus, is robust to PS. Through simulations, we presented that under various disease scenarios the FB-GGRF has improved power over a commonly used family-based sequence kernel association test (FB-SKAT). Further, similar to GGRF, the proposed FB-GGRF method is asymptotically well-behaved, and does not require empirical adjustment of the type I error rates. We illustrate the proposed method using a study of congenital heart defects with family trios from the National Birth Defects Prevention Study (NBDPS).

  13. African Americans and Glaucoma

    MedlinePlus

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

  14. Black African Traditional Mathematics

    ERIC Educational Resources Information Center

    Zaslavsky, Claudia

    1970-01-01

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

  15. 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.

  16. 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.

  17. Implementation and evaluation of the Level Set method: Towards efficient and accurate simulation of wet etching for microengineering applications

    NASA Astrophysics Data System (ADS)

    Montoliu, C.; Ferrando, N.; Gosálvez, M. A.; Cerdá, J.; Colom, R. J.

    2013-10-01

    The use of atomistic methods, such as the Continuous Cellular Automaton (CCA), is currently regarded as a computationally efficient and experimentally accurate approach for the simulation of anisotropic etching of various substrates in the manufacture of Micro-electro-mechanical Systems (MEMS). However, when the features of the chemical process are modified, a time-consuming calibration process needs to be used to transform the new macroscopic etch rates into a corresponding set of atomistic rates. Furthermore, changing the substrate requires a labor-intensive effort to reclassify most atomistic neighborhoods. In this context, the Level Set (LS) method provides an alternative approach where the macroscopic forces affecting the front evolution are directly applied at the discrete level, thus avoiding the need for reclassification and/or calibration. Correspondingly, we present a fully-operational Sparse Field Method (SFM) implementation of the LS approach, discussing in detail the algorithm and providing a thorough characterization of the computational cost and simulation accuracy, including a comparison to the performance by the most recent CCA model. We conclude that the SFM implementation achieves similar accuracy as the CCA method with less fluctuations in the etch front and requiring roughly 4 times less memory. Although SFM can be up to 2 times slower than CCA for the simulation of anisotropic etchants, it can also be up to 10 times faster than CCA for isotropic etchants. In addition, we present a parallel, GPU-based implementation (gSFM) and compare it to an optimized, multicore CPU version (cSFM), demonstrating that the SFM algorithm can be successfully parallelized and the simulation times consequently reduced, while keeping the accuracy of the simulations. Although modern multicore CPUs provide an acceptable option, the massively parallel architecture of modern GPUs is more suitable, as reflected by computational times for gSFM up to 7.4 times faster than

  18. 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.

  19. 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…

  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. Validation of five minimally obstructive methods to estimate physical activity energy expenditure in young adults in semi-standardized settings.

    PubMed

    Schneller, Mikkel B; Pedersen, Mogens T; Gupta, Nidhi; Aadahl, Mette; Holtermann, Andreas

    2015-03-13

    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.

  2. 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

  3. African American cancer patients' pain experience.

    PubMed

    Im, Eun-Ok; Lim, Hyun-Ju; Clark, Maresha; Chee, Wonshik

    2008-01-01

    Although very little is known about African American cancer patients' pain experience, a few studies have indicated that their cancer pain experience is unique and somewhat different from that of other ethnic groups. The purpose of the study reported in this article was to explore African American cancer patients' pain experience using an online forum. This study was a qualitative online forum designed from a feminist perspective and conducted among 11 African American cancer patients who were recruited through both Internet and real settings. Nine online forum topics were used to administer the 6-month online forum, and the data were analyzed using thematic analysis. Four themes emerged through the data analysis process. First, participants viewed cancer as a challenge in life that they should fight against. Second, cancer pain was differentiated from ordinary pain because cancer was stigmatized in their culture. Third, participants viewed that African Americans, especially women, were culturally raised to be strong, and this African American cultural heritage inhibited cancer patients from expressing pain and seeking help for pain management. Finally, the findings indicated certain changes in perspectives among African American cancer patients during the disease process, which might make them tolerate pain through praying to God and reading the Bible. Based on the findings, we suggest further studies among diverse groups of African American cancer patients, with a focus on cultural attitudes toward cancer pain and influences of family on cancer pain experience.

  4. 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…

  5. 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.

  6. 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.

  7. 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

  8. Strong postcranial size dimorphism in Australopithecus afarensis: results from two new resampling methods for multivariate data sets with missing data.

    PubMed

    Gordon, Adam D; Green, David J; Richmond, Brian G

    2008-03-01

    There is considerable debate over the level of size dimorphism and inferred social behavior of Australopithecus afarensis. Most previous studies have analyzed size variation in single variables or multiple variables drawn from single elements. These approaches suffer from small sample sizes, underscoring the need for new techniques that incorporate measurements from multiple unassociated elements, reducing the influence of random sampling on size variation in fossil samples. One such technique, the template method, has recently been proposed but is limited to samples with a template specimen and is sensitive to a number of assumptions. Here we present two new resampling methods that do not require a template specimen, allow measurements from multiple unassociated elements to be included in a single analysis, and allow for significance tests between comparative and fossil multivariate data sets with missing data. Using these new methods, multivariate postcranial size dimorphism is measured using eight measurements of the femur, tibia, humerus, and radius in samples of A. afarensis, modern humans, chimpanzees, gorillas, and orangutans. Postcranial dimorphism in A. afarensis is similar to that of gorillas and orangutans, and significantly greater than in modern humans and chimpanzees. Because studies in living primates have examined the association of behavior with dimorphism in body mass and craniodental measurements, not postcrania, relationships between postcranial dimorphism and social behavior must be established to make robust behavioral inferences for A. afarensis. However, the results of this and past studies strongly suggest behavioral and mating strategies differed between A. afarensis and modern humans.

  9. Oncology nurses' perceptions of their relations with family members in an ambulatory cancer care setting: a mixed methods study.

    PubMed

    Lobchuk, Michelle; Udod, Sonia

    2011-01-01

    Trends signal an increasing prevalence of people living through and beyond a cancer diagnosis with an enhanced reliance on ambulatory cancer care services and family caregiving. Despite this trend, there has been limited focus on nurses' experiences with providing support to families who care for patients in the community. For oncology nurses in ambulatory care settings, job satisfaction has decreased significantly as they are concerned with their ability to consistently provide safe and quality care to patients and their family. Although other studies indicated that the lack of time and limited resources are regrettably accepted aspects of nurses' work environments, our mixed methods small-scale study addressed how work environments still can meet the growing need for enhanced support and relations among nurses, patients, and families in ambulatory cancer care.

  10. The TRICLOBS Dynamic Multi-Band Image Data Set for the Development and Evaluation of Image Fusion Methods.

    PubMed

    Toet, Alexander; Hogervorst, Maarten A; Pinkus, Alan R

    2016-01-01

    The fusion and enhancement of multiband nighttime imagery for surveillance and navigation has been the subject of extensive research for over two decades. Despite the ongoing efforts in this area there is still only a small number of static multiband test images available for the development and evaluation of new image fusion and enhancement methods. Moreover, dynamic multiband imagery is also currently lacking. To fill this gap we present the TRICLOBS dynamic multi-band image data set containing sixteen registered visual (0.4-0.7μm), near-infrared (NIR, 0.7-1.0μm) and long-wave infrared (LWIR, 8-14μm) motion sequences. They represent different military and civilian surveillance scenarios registered in three different scenes. Scenes include (military and civilian) people that are stationary, walking or running, or carrying various objects. Vehicles, foliage, and buildings or other man-made structures are also included in the scenes. This data set is primarily intended for the development and evaluation of image fusion, enhancement and color mapping algorithms for short-range surveillance applications. The imagery was collected during several field trials with our newly developed TRICLOBS (TRI-band Color Low-light OBServation) all-day all-weather surveillance system. This system registers a scene in the Visual, NIR and LWIR part of the electromagnetic spectrum using three optically aligned sensors (two digital image intensifiers and an uncooled long-wave infrared microbolometer). The three sensor signals are mapped to three individual RGB color channels, digitized, and stored as uncompressed RGB (false) color frames. The TRICLOBS data set enables the development and evaluation of (both static and dynamic) image fusion, enhancement and color mapping algorithms. To allow the development of realistic color remapping procedures, the data set also contains color photographs of each of the three scenes. The color statistics derived from these photographs can be used to

  11. The TRICLOBS Dynamic Multi-Band Image Data Set for the Development and Evaluation of Image Fusion Methods

    PubMed Central

    Hogervorst, Maarten A.; Pinkus, Alan R.

    2016-01-01

    The fusion and enhancement of multiband nighttime imagery for surveillance and navigation has been the subject of extensive research for over two decades. Despite the ongoing efforts in this area there is still only a small number of static multiband test images available for the development and evaluation of new image fusion and enhancement methods. Moreover, dynamic multiband imagery is also currently lacking. To fill this gap we present the TRICLOBS dynamic multi-band image data set containing sixteen registered visual (0.4–0.7μm), near-infrared (NIR, 0.7–1.0μm) and long-wave infrared (LWIR, 8–14μm) motion sequences. They represent different military and civilian surveillance scenarios registered in three different scenes. Scenes include (military and civilian) people that are stationary, walking or running, or carrying various objects. Vehicles, foliage, and buildings or other man-made structures are also included in the scenes. This data set is primarily intended for the development and evaluation of image fusion, enhancement and color mapping algorithms for short-range surveillance applications. The imagery was collected during several field trials with our newly developed TRICLOBS (TRI-band Color Low-light OBServation) all-day all-weather surveillance system. This system registers a scene in the Visual, NIR and LWIR part of the electromagnetic spectrum using three optically aligned sensors (two digital image intensifiers and an uncooled long-wave infrared microbolometer). The three sensor signals are mapped to three individual RGB color channels, digitized, and stored as uncompressed RGB (false) color frames. The TRICLOBS data set enables the development and evaluation of (both static and dynamic) image fusion, enhancement and color mapping algorithms. To allow the development of realistic color remapping procedures, the data set also contains color photographs of each of the three scenes. The color statistics derived from these photographs can be

  12. 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.

  13. Segmentation and Analysis of Corpus Callosum in Alzheimer MR Images using Total Variation Based Diffusion Filter and Level Set Method.

    PubMed

    Anandh, K R; Sujatha, C M; Ramakrishnan, S

    2015-01-01

    Alzheimer’s Disease (AD) is a common form of dementia that affects gray and white matter structures of brain. Manifestation of AD leads to cognitive deficits such as memory impairment problems, ability to think and difficulties in performing day to day activities. Although the etiology of this disease is unclear, imaging biomarkers are highly useful in the early diagnosis of AD. Magnetic resonance imaging is an indispensible non-invasive imaging modality that reflects both the geometry and pathology of the brain. Corpus Callosum (CC) is the largest white matter structure as well as the main inter-hemispheric fiber connection that undergoes regional alterations due to AD. Therefore, segmentation and feature extraction are predominantly essential to characterize the CC atrophy. In this work, an attempt has been made to segment CC using edge based level set method. Prior to segmentation, the images are pre-processed using Total Variation (TV) based diffusion filtering to enhance the edge information. Shape based geometric features are extracted from the segmented CC images to analyze the CC atrophy. Results show that the edge based level set method is able to segment CC in both the normal and AD images. TV based diffusion filtering has performed uniform region specific smoothing thereby preserving the texture and small scale details of the image. Consequently, the edge map of CC in both the normal and AD are apparently sharp and distinct with continuous boundaries. This facilitates the final contour to correctly segment CC from the nearby structures. The extracted geometric features such as area, perimeter and minor axis are found to have the percentage difference of 5.97%, 22.22% and 9.52% respectively in the demarcation of AD subjects. As callosal atrophy is significant in the diagnosis of AD, this study seems to be clinically useful.

  14. Field, geochemistry and Sr-Nd isotopes of the Pan-African granitoids from the Tifnoute Valley (Sirwa, Anti-Atlas, Morocco): a post-collisional event in a metacratonic setting

    NASA Astrophysics Data System (ADS)

    Toummite, A.; Liegeois, J. P.; Gasquet, D.; Bruguier, O.; Beraaouz, E. H.; Ikenne, M.

    2013-10-01

    In the Tifnoute Valley, three plutonic units have been defined: the Askaoun intrusion, the Imourkhssen intrusion and the Ougougane group of small intrusions. They are made of quartz diorite, granodiorite and granite and all contain abundant mafic microgranular enclaves (MME). The Askaoun granodiorite and the Imourkhssen granite have been dated by LA-ICP-MS on zircon at 558 ± 2 Ma and 561 ± 3 Ma, respectively. These granitic intrusions are subcontemporaneous to the widespread volcanic and volcano-detrital rocks from the Ouarzazate Group (580-545 Ma), marking the post-collisional transtensional period in the Anti-Atlas and which evolved towards alkaline and tholeiitic lavas in minor volume at the beginning of the Cambrian anorogenic intraplate extensional period. Geochemically, the Tifnoute Valley granitoids belong to an alkali-calcic series (high-K calc-alkaline) with typical Nb-Ta negative anomalies and no alkaline affinities. Granitoids and enclaves display positive ɛNd-560Ma (+0.8 to +3.5) with young Nd-TDM between 800 and 1200 Ma and relatively low 87Sr/86Sr initial ratios (Sri: 0.7034 and 0.7065). These values indicate a mainly juvenile source corresponding to a Pan-African metasomatized lithospheric mantle partly mixed with an old crustal component from the underlying West African Craton (WAC). Preservation in the Anti-Atlas of pre-Pan-African lithologies (c. 2.03 Ga basement, c. 800 Ma passive margin greenschist-facies sediments, allochthonous 750-700 Ma ophiolitic sequences) indicates that the Anti-Atlas lithosphere has not been thickened and was never an active margin during the Neoproterozoic. After a transpressive period, the late Ediacaran period (580-545 Ma) is marked by movement on near vertical transtensional faults, synchronous with the emplacement of the huge Ouarzazate Group and the Tifnoute Valley granitoids. We propose here a geodynamical model where the Tifnoute Valley granitoids as well as the Ouarzazate Group were generated during the post

  15. 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

  16. Calibration and comparison of the Gaussian-2, complete basis set, and density functional methods for computational thermochemistry

    NASA Astrophysics Data System (ADS)

    Petersson, G. A.; Malick, David K.; Wilson, William G.; Ochterski, Joseph W.; Montgomery, J. A.; Frisch, M. J.

    1998-12-01

    We have reexamined several high-accuracy Gaussian-2, complete basis set and density functional methods for computational thermochemistry (in order of increasing speed): G2, G2(MP2), CBS-Q, G2(MP2,SVP), CBS-q, CBS-4, and B3LYP/6-311+G(3df,2p). We have employed ΔfH2980 for the "extended G2 neutral test set" for this comparison. Several errors in previous studies have been corrected and experimental spin-orbit interactions have been included in all calculated atomic energies. The mean absolute deviations from experiment are 1.43, 1.76, 1.19, 1.64, 2.34, 2.66, and 3.43 kcal/mol, respectively. The maximum deviations from experiment are 10.6, 8.8, 8.1, 9.4, 11.4, 12.9, and 24.1 kcal/mol respectively. The species responsible for these maximum errors are in order: SiF4, SiF4, Cl2C=CCl2, F2C=CF2, ClF3, ClF3, and SiCl4. All seven methods have relatively large errors for bonds to halogens, but these errors are sufficiently systematic to benefit from empirical corrections. After a discussion of ill conditioning in the "bond separation reaction" implementation of isodesmic reactions, we determine "isodesmic bond additivity corrections" (BACs) for several types of bonds by least-squares fits to the heats of formation for 76 organic species with up to ten carbons and a variety of heteroatoms. The mean absolute deviations are reduced from 1.49, 1.93, 1.22, 1.53, 2.28, 3.09, and 3.45 kcal/mol to 0.55, 0.57, 0.77, 0.63, 1.03, 0.98, and 1.16 kcal/mol. The maximum errors are reduced to about 3 kcal/mol for all but the DFT method (4.2 kcal/mol). The BACs are especially useful for larger molecules with many similar bonds. For example, the CBS-Q error for Cl2C=CCl2 is reduced from 8.1 to 3.0 kcal/mol and the CBS-4 errors for benzene and naphthalene are reduced from 10.5 and 17.5 to 2.1 and 1.6 kcal/mol, respectively.

  17. Multi-criteria decision-making methods with optimism and pessimism based on Atanassov's intuitionistic fuzzy sets

    NASA Astrophysics Data System (ADS)

    Chen, Ting-Yu

    2012-05-01

    The theory of Atanassov's intuitionistic fuzzy sets (A-IFSs) developed over the last several decades has found useful application in fields requiring multiple-criteria decision analysis. Since the membership-nonmembership pair in A-IFSs belongs to the bivariate unipolarity type, this article describes an approach that relates optimism and pessimism to multi-criteria decision analysis in an intuitionistic fuzzy-decision environment. First, several optimistic and pessimistic point operators were defined to alter the estimation of decision outcomes. Next, based on the core of the estimations, optimistic and pessimistic score functions were developed to evaluate each alternative with respect to each criterion. The suitability function was then established to determine the degree to which each an alternative satisfies the decision maker's requirement. Because the information on multiple criteria corresponding to decision importance is often incomplete, this study included suitability functions in the optimisation models to account for poorly known membership grades. Using a linear equal-weighted summation method, these models were transformed into a single objective optimisation model to generate the optimal weights for criteria. The feasibility and effectiveness of the proposed methods were illustrated through a practical example. Finally, computational experiments with enormous amounts of simulation data were designed to conduct a comparative analysis on the ranking orders yielded by different optimistic/pessimistic point operators.

  18. The Moving Boundary Node Method: A level set-based, finite volume algorithm with applications to cell motility

    PubMed Central

    Wolgemuth, Charles W.; Zajac, Mark

    2010-01-01

    Eukaryotic cell crawling is a highly complex biophysical and biochemical process, where deformation and motion of a cell are driven by internal, biochemical regulation of a poroelastic cytoskeleton. One challenge to building quantitative models that describe crawling cells is solving the reaction-diffusion-advection dynamics for the biochemical and cytoskeletal components of the cell inside its moving and deforming geometry. Here we develop an algorithm that uses the level set method to move the cell boundary and uses information stored in the distance map to construct a finite volume representation of the cell. Our method preserves Cartesian connectivity of nodes in the finite volume representation while resolving the distorted cell geometry. Derivatives approximated using a Taylor series expansion at finite volume interfaces lead to second order accuracy even on highly distorted quadrilateral elements. A modified, Laplacian-based interpolation scheme is developed that conserves mass while interpolating values onto nodes that join the cell interior as the boundary moves. An implicit time-stepping algorithm is used to maintain stability. We use the algoirthm to simulate two simple models for cellular crawling. The first model uses depolymerization of the cytoskeleton to drive cell motility and suggests that the shape of a steady crawling cell is strongly dependent on the adhesion between the cell and the substrate. In the second model, we use a model for chemical signalling during chemotaxis to determine the shape of a crawling cell in a constant gradient and to show cellular response upon gradient reversal. PMID:20689723

  19. 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.

  20. 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.

  1. 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.

  2. 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:…

  3. 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…

  4. Dry Blood Spots a Reliable Method for Measurement of Hepatitis B Viral Load in Resource-Limited Settings

    PubMed Central

    Stene-Johansen, Kathrine; Yaqoob, Nadeem; Overbo, Joakim; Aberra, Hanna; Desalegn, Hailemichael; Berhe, Nega; Johannessen, Asgeir

    2016-01-01

    Background & Aims Hepatitis B virus (HBV) quantification is essential in the management of chronic hepatitis B, both to determine treatment eligibility and in the monitoring of treatment effect. This test, however, is rarely available in resource-limited settings due to high costs and stringent requirements for shipment and storage of plasma. Dried Blood Spots (DBS) can be a convenient alternative to plasma, but its use for HBV monitoring has not been investigated under real-life conditions in Africa. Methods The performance of DBS in HBV quantification was investigated using a modified commercial test (Abbott RealTime HBV assay). Paired DBS and plasma samples were collected from an HBV positive cohort in Addis Ababa, Ethiopia. DBS were stored at ambient temperature for 4–39 days before shipment to the laboratory. Results Twenty-six paired samples were selected covering the total range of quantification, from 2.14 log IU/ml to >7 log IU/ml. HBV was detected in 21 of 21 (100%) DBS from patients with a corresponding plasma viral load above 2.70 log IU/ml. The mean difference between plasma and DBS was 0.59 log IU/ml, and the correlation was strong (R2 = 0.92). In stability studies there was no significant change in DBS viral load after storage at room temperature for up to 12 weeks. Conclusions This study suggests that DBS can be a feasible and reliable alternative to plasma for quantification of HBV in resource-limited settings. DBS can expand access to antiviral treatment for patients in low- and middle-income countries. PMID:27820845

  5. The South Asian heart lifestyle intervention (SAHELI) study to improve cardiovascular risk factors in a community setting: Design and methods

    PubMed Central

    Kandula, Namratha R.; Patel, Yasin; Dave, Swapna; Seguil, Paola; Kumar, Santosh; Baker, David W.; Spring, Bonnie; Siddique, Juned

    2013-01-01

    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 6 weeks of group classes, followed by 12 weeks 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. PMID:24060673

  6. 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

  7. [African population in history].

    PubMed

    Yang, S

    1984-11-29

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

  8. 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

  9. 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.

  10. Sharp Interface Level Set Method based Study for Evaporation of a Sessile Droplet on Hydrophilic and Hydrophobic Substrates

    NASA Astrophysics Data System (ADS)

    Shaikh, Javed; Sharma, Atul; Bhardwaj, Rajneesh

    2016-11-01

    The evaporation of a sessile droplet is important in many applications like hot-spot cooling, surface patterning etc. An understanding of the droplet dynamics in terms of evaporation rate, evaporative cooling and substrate wettability is important for designing the droplet based devices. Extensive theoretical and experimental research has been conducted on evaporating droplets in recent years; however, the effect of surrounding vapors on the evaporation dynamics of a sessile droplet is not found in the literature. In this work, an in-house sharp-interface level set code based on the Ghost Fluid Method (GFM) is used. Energy, species, and momentum equations are coupled for studying the sessile droplet evaporation phenomenon on hydrophilic and hydrophobic substrates. Different modes of droplet evaporation i.e. constant contact radius (CCR), constant contact angle (CCA) are observed for the two types of substrates. The coupling of energy and species equations is used for capturing the evaporating cooling induced dip in the droplet surface temperature. The effect of surrounding vapors like fluorocarbon vapors, on the evaporative cooling, is presented for water droplet on the hydrophilic and hydrophobic substrates. Research Scholar.

  11. Diagnostic Accuracy of the Small Membrane Filtration Method for Diagnosis of Pulmonary Tuberculosis in a High-HIV-Prevalence Setting

    PubMed Central

    Boum, Yap; Kim, Soyeon; Orikiriza, Patrick; Acuña-Villaorduña, Carlos; Vinhas, Solange; Bonnet, Maryline; Nyehangane, Dan; Mwanga-Amumpaire, Juliet; Fennelly, Kevin P.

    2016-01-01

    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

  12. 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

  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. Group versus modified individual standard-setting on multiple-choice questions with the Angoff method for fourth-year medical students in the internal medicine clerkship

    PubMed Central

    Senthong, Vichai; Chindaprasirt, Jarin; Sawanyawisuth, Kittisak; Aekphachaisawat, Noppadol; Chaowattanapanit, Suteeraporn; Limpawattana, Panita; Choonhakarn, Charoen; Sookprasert, Aumkhae

    2013-01-01

    Background The Angoff method is one of the preferred methods for setting a passing level in an exam. Normally, group meetings are required, which may be a problem for busy medical educators. Here, we compared a modified Angoff individual method to the conventional group method. Methods Six clinical instructors were divided into two groups matched by teaching experience: modified Angoff individual method (three persons) and conventional group method (three persons). The passing scores were set by using the Angoff theory. The groups set the scores individually and then met to determine the passing score. In the modified Angoff individual method, passing scores were judged by each instructor and the final passing score was adjusted by the concordance method and reliability index. Results There were 94 fourth-year medical students who took the test. The mean (standard deviation) test score was 65.35 (8.38), with a median of 64 (range 46–82). The three individual instructors took 45, 60, and 60 minutes to finish the task, while the group spent 90 minutes in discussion. The final passing score in the modified Angoff individual method was 52.18 (56.75 minus 4.57) or 52 versus 51 from the standard group method. There was not much difference in numbers of failed students by either method (four versus three). Conclusion The modified Angoff individual method may be a feasible way to set a standard passing score with less time consumed and more independent rather than group work by instructors. PMID:24101890

  15. A Mixed Methods Study of a Health Worker Training Intervention to Increase Syndromic Referral for Gambiense Human African Trypanosomiasis in South Sudan

    PubMed Central

    Palmer, Jennifer J.; Surur, Elizeous I.; Checchi, Francesco; Ahmad, Fayaz; Ackom, Franklin Kweku; Whitty, Christopher J. M.

    2014-01-01

    Background Active screening by mobile teams is considered the most effective method for detecting gambiense-type human African trypanosomiasis (HAT) but constrained funding in many post-conflict countries limits this approach. Non-specialist health care workers (HCWs) in peripheral health facilities could be trained to identify potential cases for testing based on symptoms. We tested a training intervention for HCWs in peripheral facilities in Nimule, South Sudan to increase knowledge of HAT symptomatology and the rate of syndromic referrals to a central screening and treatment centre. Methodology/Principal Findings We trained 108 HCWs from 61/74 of the public, private and military peripheral health facilities in the county during six one-day workshops and assessed behaviour change using quantitative and qualitative methods. In four months prior to training, only 2/562 people passively screened for HAT were referred from a peripheral HCW (0 cases detected) compared to 13/352 (2 cases detected) in the four months after, a 6.5-fold increase in the referral rate observed by the hospital. Modest increases in absolute referrals received, however, concealed higher levels of referral activity in the periphery. HCWs in 71.4% of facilities followed-up had made referrals, incorporating new and pre-existing ideas about HAT case detection into referral practice. HCW knowledge scores of HAT symptoms improved across all demographic sub-groups. Of 71 HAT referrals made, two-thirds were from new referrers. Only 11 patients completed the referral, largely because of difficulties patients in remote areas faced accessing transportation. Conclusions/Significance The training increased knowledge and this led to more widespread appropriate HAT referrals from a low base. Many referrals were not completed, however. Increasing access to screening and/or diagnostic tests in the periphery will be needed for greater impact on case-detection in this context. These data suggest it may be

  16. 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

  17. 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.

  18. Ensuring that the competent are truly competent: an overview of common methods and procedures used to set standards on high-stakes examinations.

    PubMed

    De Champlain, André F

    2004-01-01

    Determining whether or not an examinee has met an adequate standard of performance constitutes a central task for licensure and certification bodies. Consequently, standard setting is a key activity for all certification and licensing testing programs. The purpose of this article is to provide an overview of methods that have been proposed for set a passing standard on an examination. First, the distinction between norm-referenced and criterion-referenced methods for setting a standard will be outlined. Then, both test-centered and examinee-centered methods for setting a passing standard will be explicated. The importance of factoring in the consequences of adopting a standard will also be illustrated via the Hofstee method. In the concluding section, important issues pertaining to the selection of panelists as well as the validation of the standard will be addressed briefly.

  19. 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…

  20. 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)

  1. 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).

  2. 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…

  3. 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…

  4. Characterization of full set material constants of piezoelectric materials based on ultrasonic method and inverse impedance spectroscopy using only one sample

    NASA Astrophysics Data System (ADS)

    Li, Shiyang; Zheng, Limei; Jiang, Wenhua; Sahul, Raffi; Gopalan, Venkatraman; Cao, Wenwu

    2013-09-01

    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.

  5. 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.

  6. Understanding African American Males

    ERIC Educational Resources Information Center

    Bell, Edward Earl

    2010-01-01

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

  7. Africans Away from Home.

    ERIC Educational Resources Information Center

    Clarke, John Henrik

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

  8. Educating African American Males

    ERIC Educational Resources Information Center

    Bell, Edward E.

    2010-01-01

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

  9. 16 Extraordinary African Americans.

    ERIC Educational Resources Information Center

    Lobb, Nancy

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

  10. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

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