121 research outputs found

    Capacity Requirements of Traffic Handling Schemes in Multi-Service Networks

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    Cataloged from PDF version of article.This paper deals with the impact of traffic handling mechanisms on capacity for different network architectures. Three traffic handling models are considered: per-flow, class-based and best-effort (BE). These models can be used to meet service guarantees, the major differences being in their complexity of implementations and in the quantity of network resources that must be provided. In this study, the performance is fixed and the required capacity determined for various combinations of traffic handling architectures for edge-core networks. This study provides a comparison of different QoS architectures. One key result of this work is that on the basis of capacity requirements, there is no significant difference between semi-aggregate traffic handling and per-flow traffic handling. However, best-effort handling requires significantly more capacity as compared to the other methods. (C) 2004 Elsevier B.V. All rights reserve

    Peasant farmer–raptor conflicts around Chembe Bird Sanctuary, Zambia, Central Africa: poultry predation, ethno–biology, land use practices and conservation

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    Los conflictos entre campesinos y rapaces alrededor del refugio de Chembe Bird, en Zambia, África central: depredación de aves de corral, etnobiología, prácticas de uso de la tierra y conservación Las rapaces prestan servicios ecosistémicos a las comunidades rurales de África: (1) depredando roedores, (2) regulando las poblaciones de serpientes dañinas, (3) configurando las creencias culturales y (4) formando parte de las atracciones turísticas. Sin embargo, los campesinos las relacionan con la disminución de las aves de corral, las profecías telepáticas y la brujería tradicional. En consecuencia, las rapaces son perseguidas por los humanos. Mediante una técnica de análisis cualitativo de contenido, analizamos la interacción entre los campesinos y las rapaces en zonas adyacentes al refugio de Chembe Bird. Nuestros resultados revelan las prácticas, actitudes y percepciones negativas que podrían poner en peligro de extinción a cinco rapaces en la zona de estudio. A fin de mejorar la coexistencia entre agricultores y rapaces, proponemos utilizar medidas transformadoras de carácter conceptual (por ejemplo, sensibilizar a las partes interesadas, garantizar el cumplimiento riguroso de la legislación relativa a las rapaces y proteger su hábitat, así como reforzar el capital social relacional) y medidas prácticas (como proporcionar cercados apropiados y aves de corral de fenotipos de alta resistencia).Los conflictos entre campesinos y rapaces alrededor del refugio de Chembe Bird, en Zambia, África central: depredación de aves de corral, etnobiología, prácticas de uso de la tierra y conservación Las rapaces prestan servicios ecosistémicos a las comunidades rurales de África: (1) depredando roedores, (2) regulando las poblaciones de serpientes dañinas, (3) configurando las creencias culturales y (4) formando parte de las atracciones turísticas. Sin embargo, los campesinos las relacionan con la disminución de las aves de corral, las profecías telepáticas y la brujería tradicional. En consecuencia, las rapaces son perseguidas por los humanos. Mediante una técnica de análisis cualitativo de contenido, analizamos la interacción entre los campesinos y las rapaces en zonas adyacentes al refugio de Chembe Bird. Nuestros resultados revelan las prácticas, actitudes y percepciones negativas que podrían poner en peligro de extinción a cinco rapaces en la zona de estudio. A fin de mejorar la coexistencia entre agricultores y rapaces, proponemos utilizar medidas transformadoras de carácter conceptual (por ejemplo, sensibilizar a las partes interesadas, garantizar el cumplimiento riguroso de la legislación relativa a las rapaces y proteger su hábitat, así como reforzar el capital social relacional) y medidas prácticas (como proporcionar cercados apropiados y aves de corral de fenotipos de alta resistencia).Raptors provide ecosystem services to African rural communities by: (1) preying on rodents, (2) regulating harmful snake populations, (3) shaping cultural beliefs, and (4) being part of tourist attractions. Peasant farmers, however, connect them with poultry depletion, telepathic omens, and traditional witchcraft. Consequently, raptors suffer human–induced persecution. Using a qualitative content analysis technique, we investigated the interaction between farmers and raptors in areas adjoining the Chembe Bird Sanctuary. Our results unravel negative perceptions, attitudes and practices that could threaten the extinction of five raptors in the study area. We propose the use of transformative cognitive measures (e.g., raising stakeholder awareness, ensuring stringent law enforcement for raptors and protecting their habitat, and strengthening relational social capital) and physical measures (e.g., providing appropriate fencing and poultry breeding of high resilient phenotypes) to improve the co–existence between farmers and raptors

    An investigation of factors associated with the health and well-being of HIV-infected or HIV-affected older people in rural South Africa

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    BackgroundDespite the severe impact of HIV in sub-Saharan Africa, the health of older people aged 50+ is often overlooked owing to the dearth of data on the direct and indirect effects of HIV on older people's health status and well-being. The aim of this study was to examine correlates of health and well-being of HIV-infected older people relative to HIV-affected people in rural South Africa, defined as participants with an HIV-infected or death of an adult child due to HIV-related cause. MethodsData were collected within the Africa Centre surveillance area using instruments adapted from the World Health Organization (WHO) Study on global AGEing and adult health (SAGE). A stratified random sample of 422 people aged 50+ participated. We compared the health correlates of HIV-infected to HIV-affected participants using ordered logistic regressions. Health status was measured using three instruments: disability index, quality of life and composite health score. ResultsMedian age of the sample was 60 years (range 50-94). Women HIV-infected (aOR 0.15, 95% confidence interval (CI) 0.08-0.29) and HIV-affected (aOR 0.20, 95% CI 0.08-0.50), were significantly less likely than men to be in good functional ability. Women's adjusted odds of being in good overall health state were similarly lower than men's; while income and household wealth status were stronger correlates of quality of life. HIV-infected participants reported better functional ability, quality of life and overall health state than HIV-affected participants. Discussion and Conclusions The enhanced healthcare received as part of anti-retroviral treatment as well as the considerable resources devoted to HIV care appear to benefit the overall well-being of HIV-infected older people; whereas similar resources have not been devoted to the general health needs of HIV uninfected older people. Given increasing numbers of older people, policy and programme interventions are urgently needed to holistically meet the health and well-being needs of older people beyond the HIV-related care system. <br/

    Sexually transmitted infections among HIV serodiscordant partners: A secondary analysis of HIV Prevention Trial Network 052

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    Sexually transmitted infections (STIs) remain a public health concern because of their interaction(s) with HIV. In the HPTN 052 study, STIs were evaluated in both HIV-positive index cases and their HIV-negative partners at enrollment and at yearly follow-up visits. Our definition for STI was based on any infection with Chlamydia trachomatis, Neisseria gonorrhoeae, syphilis, or Trichomonas vaginalis. We used log-binomial regression models to identify factors associated with prevalent STIs. Generalized estimating equation models with the Poisson distribution were used to compare STI incidence between HIV-positive index cases and HIV-negative partners. 8.1% of the participants had STIs at enrollment. The prevalence of STIs (8.9 vs. 7.2) was higher in HIV-positive index cases than HIV-negative partners. Being female (prevalence ratio (PR) = 1.61; 95% CI: 1.20–2.16) or unmarried (PR = 1.92; 95% CI: 1.17–3.14) was associated with prevalent STIs. Compared to HIV-negative male partners, HIV-positive female index cases had a higher risk of STI acquisition (incidence rate ratio (IRR) = 2.25; 95% CI: 1.70–2.97). While we are implementing HIV prevention interventions for HIV-negative people, we should also intensify targeted STI prevention interventions, especially among HIV-positive women

    Geospatial transmission hotspots of recent HIV infection — Malawi, October 2019–March 2020

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    What is already known about this topic? A novel HIV infection surveillance initiative was implemented in Malawi to collect data on recent HIV infections among new diagnoses to characterize the epidemic and guide the public health response. What is added by this report? Higher proportions of recent infections were identified among females, persons aged <30 years, and clients at maternal and child health and youth clinics. Spatial analysis identified three hotspots of health facilities with significantly higher rates of recent infection than expected across five districts. What are the implications for public health practice? Geospatial analysis of recent HIV infection surveillance data can identify potential transmission hotspots. This information could be used to tailor program activities to strengthen HIV testing, prevention, and treatment services and ultimately interrupt transmission

    New Antenatal Model in Africa and India (NAMAI) study: implementation research to improve antenatal care using WHO recommendations

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    Background: In 2020, an estimated 287 000 women died globally from pregnancy‐related causes and 2 million babies were stillborn. Many of these outcomes can be prevented by quality healthcare during pregnancy and childbirth. Within the continuum of maternal health, antenatal care (ANC) is a key moment in terms of contact with the health system, yet it remains an underutilized platform. This paper describes the protocol for a study conducted in collaboration with Ministries of Health and country research partners that aims to employ implementation science to systematically introduce and test the applicability of the adapted WHO ANC package in selected sites across four countries. Methods: Study design is a mixed methods stepped-wedge cluster randomized implementation trial with a nested cohort component (in India and Burkina Faso). The intervention is composed of two layers: (i) the country- (or state)-specific ANC package, including evidence-based interventions to improve maternal and newborn health outcomes, and (ii) the co-interventions (or implementation strategies) to help delivery and uptake of the adapted ANC package. Using COM-B model, co-interventions support behaviour change among health workers and pregnant women by (1) training health workers on the adapted ANC package and ultrasound (except in India), (2) providing supplies, (3) conducting mentoring and supervision and (4) implementing community mobilization strategies. In Rwanda and Zambia, a fifth strategy includes a digital health intervention. Qualitative data will be gathered from health workers, women and their families, to gauge acceptability of the adapted ANC package and its components, as well as experience of care. The implementation of the adapted ANC package of interventions, and their related costs, will be documented to understand to what extent the co-interventions were performed as intended, allowing for iteration. Discussion: Results from this study aim to build the global evidence base on how to implement quality ANC across different settings and inform pathways to scale, which will ultimately lead to stronger health systems with better maternal and perinatal outcomes. On the basis of the study results, governments will be able to adopt and plan for national scale-up, aiming to improve ANC nationally. This evidence will inform global guidance. Trial registration number: ISRCTN, ISRCTN16610902. Registered 27 May 2022. https://www.isrctn.com/ISRCTN16610902

    Isotropic 3D Nuclear Morphometry of Normal, Fibrocystic and Malignant Breast Epithelial Cells Reveals New Structural Alterations

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    Grading schemes for breast cancer diagnosis are predominantly based on pathologists' qualitative assessment of altered nuclear structure from 2D brightfield microscopy images. However, cells are three-dimensional (3D) objects with features that are inherently 3D and thus poorly characterized in 2D. Our goal is to quantitatively characterize nuclear structure in 3D, assess its variation with malignancy, and investigate whether such variation correlates with standard nuclear grading criteria.We applied micro-optical computed tomographic imaging and automated 3D nuclear morphometry to quantify and compare morphological variations between human cell lines derived from normal, benign fibrocystic or malignant breast epithelium. To reproduce the appearance and contrast in clinical cytopathology images, we stained cells with hematoxylin and eosin and obtained 3D images of 150 individual stained cells of each cell type at sub-micron, isotropic resolution. Applying volumetric image analyses, we computed 42 3D morphological and textural descriptors of cellular and nuclear structure.We observed four distinct nuclear shape categories, the predominant being a mushroom cap shape. Cell and nuclear volumes increased from normal to fibrocystic to metastatic type, but there was little difference in the volume ratio of nucleus to cytoplasm (N/C ratio) between the lines. Abnormal cell nuclei had more nucleoli, markedly higher density and clumpier chromatin organization compared to normal. Nuclei of non-tumorigenic, fibrocystic cells exhibited larger textural variations than metastatic cell nuclei. At p<0.0025 by ANOVA and Kruskal-Wallis tests, 90% of our computed descriptors statistically differentiated control from abnormal cell populations, but only 69% of these features statistically differentiated the fibrocystic from the metastatic cell populations.Our results provide a new perspective on nuclear structure variations associated with malignancy and point to the value of automated quantitative 3D nuclear morphometry as an objective tool to enable development of sensitive and specific nuclear grade classification in breast cancer diagnosis

    “Without a mother”: caregivers and community members’ views about the impacts of maternal mortality on families in KwaZulu-Natal, South Africa.

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    BACKGROUND: Maternal mortality in South Africa is high and a cause for concern especially because the bulk of deaths from maternal causes are preventable. One of the proposed reasons for persistently high maternal mortality is HIV which causes death both indirectly and directly. While there is some evidence for the impact of maternal death on children and families in South Africa, few studies have explored the impacts of maternal mortality on the well-being of the surviving infants, older children and family. This study provides qualitative insight into the consequences of maternal mortality for child and family well-being throughout the life-course. METHODS: This qualitative study was conducted in rural and peri-urban communities in Vulindlela, KwaZulu-Natal. The sample included 22 families directly affected by maternal mortality, 15 community stakeholders and 7 community focus group discussions. These provided unique and diverse perspectives about the causes, experiences and impacts of maternal mortality. RESULTS AND DISCUSSION: Children left behind were primarily cared for by female family members, even where a father was alive and involved. The financial burden for care and children’s basic needs were largely met through government grants (direct and indirectly targeted at children) and/or through an obligation for the father or his family to assist. The repercussions of losing a mother were felt more by older children for whom it was harder for caregivers to provide educational supervision and emotional or psychological support. Respondents expressed concerns about adolescent’s educational attainment, general behaviour and particularly girl’s sexual risk. CONCLUSION: These results illuminate the high costs to surviving children and their families of failing to reduce maternal mortality in South Africa. Ensuring social protection and community support is important for remaining children and families. Additional qualitative evidence is needed to explore differential effects for children by gender and to guide future research and inform policies and programs aimed at supporting maternal orphans and other vulnerable children throughout their development.Web of Scienc
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