Wireless sensor node mobility and its effect on transmission reliability

Abstract: Deploying a Wireless Sensor Network (WSN) poses certain challenges such as data reliability due to Electromagnetic Interference (EMI), multipath fading as well as faster energy depletion of nodes located near the base station creating communication holes in the network. Several energy efficient algorithms have been developed to improve the energy consumption of static nodes however the issue of battery depletion of nodes near the base station remains present. In this paper we attempt to model the relationship between the node mobility and the reliability of data transmission. Mobile nodes could move near static nodes experiencing high traffic in order to reduce the number of packets sent through the saturated nodes. This paper will investigate, using a real environment, the effect of speed and packet size on the reliability of the wireless link. This is a required prerequisite, prior to a detailed design of a Mobile relay node

Intersectoral (in)activity: Towards an understanding of public sector department links between water, sanitation and hygiene (WASH) and childhood undernutrition in South Africa

Associations between different forms of malnutrition and environmental conditions, including water, sanitation and hygiene (WASH), contribute to poor child health, nutritional status and physical growth. The primary responsibility for the provision of water and sanitation, as a basic service and human right, lies with the State, as such, a number of stakeholders are involved. Despite relatively high levels of WASH infrastructure coverage in South Africa, enteric infections and stunting remain high for a middle-income country. The aim of this study is to elucidate the landscape of WASH in South Africa in relation to nutritional status of children under the age of 5 years in the South African, Gauteng and City of Johannesburg contexts. The authors detailed the national and provincial public sector departments and through purposive sampling proceeded to map the various departments and associated policies that are responsible for the provision of WASH facilities, as well the nutritional status of children

Beneficial HLA-mediated viral polymorphisms on the transmitted virus additively influence disease progression in HIV-1, subtype C infection

Transmitted viral factors have been shown to affect disease progression but whether infection with viruses carrying beneficial HLA-mediated escape polymorphisms affects disease progression in HLA-mismatched participants remains controversial

Scaling Up Mental Health Services in Zambia: Challenges and Opportunities Reported in an Education Project.

yesThe need to increase the capacity of developing countries to meet the mental health needs of their populations is widely acknowledged. This article examines some of the challenges associated with a British Council DelPHE project aimed at strengthening the capacity of mental health educators to prepare the mental health workforce in Zambia for a shift from an institutional to a community-based model of care. The analysis draws on data from two focus groups in which the participants were drawn from college educators who had taken part in workshops intended to enhance curriculum alignment to ensure that the education and training provided for clinical officers (psychiatry) and mental health nurses was "fit for purpose." In particular, the article highlights their perspectives on some of the tensions in focusing on mental health as opposed to broader health care and in ensuring appropriate opportunities for practice or field placements. The continuing impact of stigma and limited resources available for mental ill-health is acknowledged within the wider context of inequities in mental health care. Findings of this evaluation may be applicable to other sub-Saharan contexts, but should be understood only within the Zambian context

Uptake of antenatal care in high HIV-prevalence settings: Results from three population-based surveys in South Africa.

BACKGROUND: Despite substantial progress in reducing pregnancy-related preventable morbidity and mortality, these remain unacceptably high in developing countries. In 2016, the World Health Organization (WHO) revised recommendations for antenatal care (ANC) from a 4-visit model to a minimum of 8 ANC contacts to reduce perinatal mortality further and improve women's experience of care. The guidelines also recommend that the first ANC visit (ANC-1) should occur during the first trimester. OBJECTIVES: To describe the uptake of routine ANC and its associated factors in South Africa (SA) prior to the 2016 WHO recommendations, when the country recommended 4 ANC visits, to bring to light potential challenges in achieving the current recommendations. METHODS: Secondary data analyses were performed from 3 facility-based, cross-sectional national surveys, conducted to measure 6-week mother-to-child transmission of HIV and coverage of related interventions in SA. These surveys recruited mother-infant pairs attending selected public primary healthcare facilities for their infants' 6-week immunisation in 2010, 2011 -2012 and 2012 -2013. Quantitative questionnaires were used to gather sociodemographic and antenatal-to-peripartum information from Road to Health cards and maternal recall. The inclusion criteria for this secondary assessment were at least 1 ANC visit, the primary outcome being uptake of ≥4 ANC visits. A multivariable logistic regression model was used to: (i) identify maternal factors associated with ANC visits; and (ii) establish whether receiving selected ANC activities was associated with frequency or timing of ANC-1. RESULTS: Of the 9 470, 9 646 and 8 763 women who attended at least 1 ANC visit, only 47.5% (95% confidence interval (CI) 45.4 -49.6), 55.6% (95% CI 53.2 -58.0) and 56.7% (95% CI 54.3 -59.1) adhered to ≥4 ANC visits, while 36.0% (95% CI 34.5 -37.5), 43.5% (95% CI 42.0 -45.1) and 50.8% (95% CI 49.3 -52.2) attended ANC-1 early (before 20 weeks' gestation) in 2010, 2011 -2012 and 2012 -2013, respectively. Multiparity and lower socioeconomic status were significantly associated with non-adherence to the 4-visit ANC recommendation, while a later survey year, higher education, being married, >19 years old, HIV-positive, planned pregnancy and knowing how HIV is transmitted vertically were strongly related to ≥4 ANC visits. The number of women who received selected ANC activities increased significantly with survey year and ≥4 ANC visits, but was not associated with timing of ANC-1. CONCLUSIONS: Despite increases in the uptake of ≥4 ANC visits and early ANC-1 rates between 2010 and 2013, these practices remain suboptimal. Adhering to ≥4 ANC visits improved coverage of selected ANC activities, implying that strengthening efforts to increase the uptake of ANC from at least 4 to 8, could improve overall outcomes

Identification of broadly neutralizing antibody epitopes in the HIV-1 envelope glycoprotein using evolutionary models

Background: Identification of the epitopes targeted by antibodies that can neutralize diverse HIV-1 strains can provide important clues for the design of a preventative vaccine. Methods: We have developed a computational approach that can identify key amino acids within the HIV-1 envelope glycoprotein that influence sensitivity to broadly cross-neutralizing antibodies. Given a sequence alignment and neutralization titers for a panel of viruses, the method works by fitting a phylogenetic model that allows the amino acid frequencies at each site to depend on neutralization sensitivities. Sites at which viral evolution influences neutralization sensitivity were identified using Bayes factors (BFs) to compare the fit of this model to that of a null model in which sequences evolved independently of antibody sensitivity. Conformational epitopes were identified with a Metropolis algorithm that searched for a cluster of sites with large Bayes factors on the tertiary structure of the viral envelope. Results: We applied our method to ID50 neutralization data generated from seven HIV-1 subtype C serum samples with neutralization breadth that had been tested against a multi-clade panel of 225 pseudoviruses for which envelope sequences were also available. For each sample, between two and four sites were identified that were strongly associated with neutralization sensitivity (2ln(BF) > 6), a subset of which were experimentally confirmed using site-directed mutagenesis. Conclusions: Our results provide strong support for the use of evolutionary models applied to cross-sectional viral neutralization data to identify the epitopes of serum antibodies that confer neutralization breadth

Exploring partnership: Reflections on an international collaboration.

yesThis article explores some of the challenges involved in a collaborative mental health partnership, drawing on the reflections of two project members from the Chainama College of Health Sciences in Zambia and the Leeds Metropolitan University in England. The aim of the project was to support the education and training of the mental health workforce in Zambia as services shift from institutional to community-based care. The discussion is located within Gray’s ‘three-pronged dilemma’ and debates concerning the internationalisation agenda in social work and higher education. The conclusion emphasises the benefits and tensions of partnership working between ‘developed’ and ‘developing’ countries

Evidence of HIV-1 adaptation to host HLA alleles following chimp-to-human transmission

<p>Abstract</p> <p>Background</p> <p>The cytotoxic T-lymphocyte immune response is important in controlling HIV-1 replication in infected humans. In this immune pathway, viral peptides within infected cells are presented to T-lymphocytes by the polymorphic human leukocyte antigens (HLA). HLA alleles exert selective pressure on the peptide regions and immune escape mutations that occur at some of the targeted sites can enable the virus to adapt to the infected host. The pattern of ongoing immune escape and reversion associated with several human HLA alleles has been studied extensively. Such mutations revert upon transmission to a host without the HLA allele because the escape mutation incurs a fitness cost. However, to-date there has been little attempt to study permanent loss of CTL epitopes due to escape mutations without an effect on fitness.</p> <p>Results</p> <p>Here, we set out to determine the extent of adaptation of HIV-1 to three well-characterized HLA alleles during the initial exposure of the virus to the human cytotoxic immune responses following transmission from chimpanzee. We generated a chimpanzee consensus sequence to approximate the virus sequence that was initially transmitted to the human host and used a method based on peptide binding affinity to HLA crystal structures to predict peptides that were potentially targeted by the HLA alleles on this sequence. Next, we used codon-based phylogenetic models to quantify the average selective pressure that acted on these regions during the period immediately following the zoonosis event, corresponding to the branch of the phylogenetic tree leading to the common ancestor of all of the HIV-1 sequences. Evidence for adaptive evolution during this period was observed at regions recognised by HLA A*6801 and A*0201, both of which are common in African populations. No evidence of adaptive evolution was observed at sites targeted by HLA-B*2705, which is a rare allele in African populations.</p> <p>Conclusion</p> <p>Our results suggest that the ancestral HIV-1 virus experienced a period of positive selective pressure due to immune responses associated with HLA alleles that were common in the infected human population. We propose that this resulted in permanent escape from immune responses targeting unconstrained regions of the virus.</p

The Unknown Risk of Vertical Transmission in Sleeping Sickness—A Literature Review

Children with human African trypanosomiasis (HAT) present with a range of generally non-specific symptoms. Late diagnosis is frequent with often tragic outcomes. Trypanosomes can infect the foetus by crossing the placenta. Unequivocal cases of congenital infection that have been reported include newborn babies of infected mothers who were diagnosed with HAT in the first 5 days of life and children of infected mothers who had never entered an endemic country themselves