40 research outputs found
The evolution in the stellar mass of Brightest Cluster Galaxies over the past 10 billion years
Using a sample of 98 galaxy clusters recently imaged in the near infra-red
with the ESO NTT, WIYN and WHT telescopes, supplemented with 33 clusters from
the ESO archive, we measure how the stellar mass of the most massive galaxies
in the universe, namely Brightest Cluster Galaxies (BCG), increases with time.
Most of the BCGs in this new sample lie in the redshift range ,
which has been noted in recent works to mark an epoch over which the growth in
the stellar mass of BCGs stalls. From this sample of 132 clusters, we create a
subsample of 102 systems that includes only those clusters that have estimates
of the cluster mass. We combine the BCGs in this subsample with BCGs from the
literature, and find that the growth in stellar mass of BCGs from 10 billion
years ago to the present epoch is broadly consistent with recent semi-analytic
and semi-empirical models. As in other recent studies, tentative evidence
indicates that the stellar mass growth rate of BCGs may be slowing in the past
3.5 billion years. Further work in collecting larger samples, and in better
comparing observations with theory using mock images is required if a more
detailed comparison between the models and the data is to be made.Comment: 15 pages, 8 tables, 7 figures - Accepted for publication in MNRA
The High Burden of Malaria in Primary School Children in Southern Malawi.
Malaria among school children has received increased attention recently, yet there remain few detailed data on the health and educational burden of malaria, especially in southern Africa. This paper reports a survey among school children in 50 schools in Zomba District, Malawi. Children were assessed for Plasmodium infection, anemia, and nutritional status and took a battery of age-appropriate tests of attention, literacy, and numeracy. Overall, 60.0% of children were infected with Plasmodium falciparum, 32.4% were anemic and 32.4% reported sleeping under a mosquito net the previous night. Patterns of P. falciparum infection and anemia varied markedly by school. In multivariable analysis, higher odds of P. falciparum infection were associated with younger age and being stunted, whereas lower odds were associated with reported net use, higher parental education, and socioeconomic status. The odds of anemia were significantly associated with P. falciparum infection, with a dose-response relationship between density of infection and odds of anemia. No clear relationship was observed between health status and cognitive and educational outcomes. The high burden of malaria highlights the need to tackle malaria among school children
Design, implementation and evaluation of a training programme for school teachers in the use of malaria rapid diagnostic tests as part of a basic first aid kit in southern Malawi.
BACKGROUND: With increasing levels of enrolment, primary schools present a pragmatic opportunity to improve the access of school children to timely diagnosis and treatment of malaria, increasingly recognised as a major health problem within this age group. The expanded use of malaria rapid diagnostic tests (RDTs) and artemisinin combination therapy (ACT) by community health workers (CHWs) has raised the prospect of whether teachers can provide similar services for school children. We describe and evaluate the training of primary school teachers to use a first aid kit containing malaria RDTs and ACT for the diagnosis and treament of uncomplicated malaria in school children in southern Malawi. METHODS: We outline the development of the intervention as: (1) conception and design, (2) pilot training, (3) final training, and (4) 7-month follow up. The training materials were piloted at a four-day workshop in July 2013 following their design at national stakeholders meetings. The evaluation of the pilot training and materials were assessed in relation to increased knowledge and skill sets using checklist evaluations and questionnaires, the results of which informed the design of a final seven-day training programme held in December 2013. A follow up of trained teachers was carried out in July 2014 following 7 months of routine implementation. A total of 15 teachers were evaluated at four stages: pilot training, two weeks following pilot, final training and seven months following final training. RESULTS: A total of 15 and 92 teachers were trained at the pilot and final training respectively. An average of 93 % of the total steps required to use RDTs were completed correctly at the final training, declining to 87 % after 7 months. All teachers were observed correctly undertaking safe blood collection and handling, accurate RDT interpretation, and correct dispensing of ACT. The most commonly observed errors were a failure to wait 20 minutes before reading the test result, and adding an incorrect volume of buffer to the test cassette. CONCLUSION: Following training, teachers are able to competently use RDTs and ACTs test and treat children at school for uncomplicated malaria safely and accurately. Teachers demonstrate a comparable level of RDT use relative to non-health professional users of RDTs, and sustain this competency over a period of seven months during routine implementation
Impact of school-based malaria case management on school attendance, health and education outcomes: a cluster randomised trial in southern Malawi.
Introduction: Evidence indicates children who suffer from ill-health are less likely to attend or complete schooling. Malaria is an important cause of morbidity and mortality in school-age children. However, they are less likely to receive malaria treatment at health facilities and evidence for how to improve schoolchildren's access to care is limited. This study aimed to evaluate the impact of a programme of school-based malaria case management on schoolchildren's attendance, health and education. Methods: A cluster randomised controlled trial was conducted in 58 primary schools in Zomba District, Malawi, 2011-2015. The intervention, implemented in 29 randomly selected schools, provided malaria rapid diagnostic tests and artemisinin-based combination therapy to diagnose and treat uncomplicated malaria as part of basic first aid kits known as 'Learner Treatment Kits' (LTK). The primary outcome was school attendance, assessed through teacher-recorded daily attendance registers and independent periodic attendance spot checks. Secondary outcomes included prevalence of Plasmodium spp infection, anaemia, educational performance, self-reported child well-being and health-seeking behaviour. A total of 9571 children from standards 1-7 were randomly selected for assessment of school attendance, with subsamples assessed for the secondary outcomes. Results: Between November 2013 and March 2015, 97 trained teachers in 29 schools provided 32 685 unique consultations. Female schoolchildren were significantly more likely than male to seek a consultation (unadjusted OR=1.78 (95% CI 1.58 to 2.00). No significant intervention effect was observed on the proportion of child-days recorded as absent in teacher registers (n=9017 OR=0.90 (95% CI 0.77 to 1.05), p=0.173) or of children absent during random school visits-spot checks (n=5791 OR=1.09 (95% CI 0.87 to 1.36), p=0.474). There was no significant impact on child-reported well-being, prevalence of Plasmodium spp, anaemia or education scores. Conclusion: Despite high community demand, the LTK programme did not reduce schoolchildren's absenteeism or improve health or education outcomes in this study setting. Trial registration number: ClinicalTrials.gov NCT02213211
Preferences for services in a patient’s first six months on antiretroviral therapy for HIV in South Africa and Zambia (PREFER): research protocol for a prospective observational cohort study [version 2; peer review: 2 approved]
Background For patients on HIV treatment in sub-Saharan Africa, the highest risk for loss from care remains the first six months after antiretroviral (ART) initiation, when patients are not yet eligible for differentiated service delivery (DSD) models that offer lower-burden, patient-centred care and thus improve treatment outcomes. To reduce early disengagement from care, the PREFER study will use a sequential mixed-methods approach to describe the characteristics, needs, concerns, and preferences of patients in South Africa and Zambia 0-6 months after ART initiation or re-initiation. Protocol PREFER is an observational, prospective cohort study of adults on ART for ≤6 months at 12 public healthcare facilities in Zambia and 18 in South Africa. Its objective is to describe and understand the needs and preferences of initiating and re-initiating ART clients to inform the design of DSD models for the early HIV treatment period, improve early treatment outcomes, and distinguish the barriers encountered by naïve patients from those facing re-initiators. It has four components: 1) survey of clients 0-6 months after ART initiation (identify characteristics and preferences of clients starting ART); 2) follow up through routinely collected medical records for <24 months after enrollment (describe resource utilization and patterns and predictors of engagement in care); 3) focus group discussions and discrete choice experiment (explore reported barriers to and facilitators of retention); and 4) in South Africa only, collection of blood samples (assess the prevalence of ARV metabolites indicating prior ART use). Conclusions PREFER aims to understand why the early treatment period is so challenging and how service delivery can be amended to address the obstacles that lead to early disengagement from care. It will generate information about client characteristics and preferences to help respond to patients’ needs and design better strategies for service delivery and improve resource allocation going forward
Preferences for services in a patient’s first six months on antiretroviral therapy for HIV in South Africa and Zambia (PREFER): research protocol for a prospective observational cohort study
Study protocol and supplementary files for protocol manuscript in Gates Open Research.BACKGROUND: For patients on HIV treatment in sub-Saharan Africa (SSA), the highest risk for loss from care consistently remains the first six months after antiretroviral (ART) initiation, when patients are not yet eligible for most existing differentiated service delivery (DSD) models. To reduce disengagement from care during this period, we must gain a comprehensive understanding of patients’ needs, concerns, resources, and preferences for service delivery during this period. The PREFER study will use a sequential mixed-methods approach to survey a sample of patients in South Africa and Zambia 0-6 months after ART initiation to develop a detailed profile of patient characteristics and needs.
PROTOCOL: PREFER is an observational, prospective cohort study of adult patients on ART for ≤6 months at 12 public sector healthcare facilities in Zambia and 18 in South Africa that aims to inform the design of DSD models for the early HIV treatment period. It has four components: 1) survey of clients 0-6 months after ART initiation; 2) follow up through routinely collected medical records for <12 or <24 months after enrollment; 3) focus group discussions to explore specific issues raised in the survey; and 4) in South Africa only, collection of blood samples self-reported naïve participants to assess the prevalence of ARV metabolites indicating prior ART use. Results will include demographic and clinical characteristics of patients, self-reported HIV care histories, preferences for treatment delivery, and predictors of disengagement.
CONCLUSIONS: PREFER aims to understand why the early treatment period is so challenging and how service delivery can be amended to address the obstacles that lead to early disengagement from care and to distinguish the barriers encountered by naïve patients to those facing re-initiators. The information collected by PREFER will help respond to patients’ needs and design better strategies for service delivery and improve resource allocation going forward.Bill & Melinda Gates Foundation, INV-031690 to Boston Universit
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
The Nemadji Review, Volume 4
Editor-in-Chief:
Seth Love;
Editor:
Katie Wolden;
Editorial Staff:
Sydnee Chipman,
Kelci Greenwood,
Mara Martinson,
Kourtney Sande,
Rebekah Kromm;
Faculty Advisors:
Jayson Iwen,
Hilary Fezzey,
John McCormickVolume 4 of The Nemadji Review. Includes poetry, short fiction, creative non-fiction, and drama