343 research outputs found

    Classification and mapping of the woody vegetation of Gonarezhou National Park, Zimbabwe

    Get PDF
    Within the framework of the Great Limpopo Transfrontier Conservation Area (GLTFCA), the purpose of this study was to produce a classification of the woody vegetation of the Gonarezhou National Park, Zimbabwe, and a map of its potential distribution. Cover-abundance data of woody species were collected in 330 georeferenced relevés across the Park. These data were used to produce two matrices: the first one using the cover-abundance values as collected in five height layers and the second one based on merging the layers into a single cover value for each species. Automatic classifications were produced for both matrices to determine the optimal number of vegetation types. The two classification approaches both produced 14 types belonging to three macro-groups: mopane, miombo and alluvial woodlands. The results of the two classifications were compared looking at the constant, dominant and diagnostic species of each type. The classification based on separate layers was considered more effective and retained. A high-resolution map of the potential distribution of vegetation types for the whole study area was produced using Random Forest. In the model, the relationship between bioclimatic and topographic variables, known to be correlated to vegetation types, and the classified relevés was used. Identified vegetation types were compared with those of other national parks within the GLTFCA, and an evaluation of the main threats and pressures was conducted. Conservation implications: Vegetation classification and mapping are useful tools for multiple purposes including: surveying and monitoring plant and animal populations, communities and their habitats, and development of management and conservation strategies. Filling the knowledge gap for the Gonarezhou National Park provides a basis for standardised and homogeneous vegetation classification and mapping for the entire Great Limpopo Transfrontier Conservation Area

    Linking the Conservation of Culture and Nature: A Case Study of Sacred Forests in Zimbabwe

    Get PDF
    This paper examines the role of traditional religious beliefs and traditional leaders in conserving remnant patches of a unique type of dry forest in the Zambezi Valley of northern Zimbabwe. We examined aerial photographs spanning more than three decades, interviewed and surveyed local residents, and met with communities to learn about the environmental history of the forests and the factors that have affected land use in the area. Our results show that forest loss is dramatically less in forests that are now considered sacred, or were in the past connected to sacred forests. This supports our hypothesis that traditional spiritual values have influenced human behavior affecting the forests, and have played a role in protecting them until now. We also found that rates of forest loss have been much higher in an area where traditional leaders are relatively disempowered within the post-independence political system compared to an area where traditional leaders have more power. These findings lead us to conclude that a strategy that links the conservation of culture and nature is likely to be more effective in conserving forests than a strategy that ignores traditional beliefs, values, and institutions

    A CE assay for the detection of agonist-stimulated adenylyl cyclase activity

    Full text link
    A CE assay was developed for the detection of adenylyl cyclase (AC) activity stimulated at the AC and G protein-coupled receptor (GPCR) level. In the assay, cell membranes overexpressing GPCR and/or AC were incubated with modulators and substrate ATP to produce cAMP in a dose-dependent manner. In both the CE-UV and a radiochemical assay, the addition of forskolin (FSK) resulted in a two- to three-fold maximum increase in AC activity with EC 50 s of 4.2 14± 140.7 and 2.4 14± 140.7 14ΜM, respectively, demonstrating that similar results were obtained by both assays. GPCR activation was also detected using cell membranes overexpressing AC and the Β 2 -adrenergic receptor (Β 2 AR) fused to the stimulatory G protein. Terbutaline (Β 2 AR agonist) increased the basal rate of cAMP formation 1.7 14± 140.1-fold resulting in an EC 50 of 62 14± 1410 14nM. The assay's ability to detect antagonists is demonstrated by the expected right-shifted EC 50 of terbutaline by the Β 2 AR antagonist propranolol. The CE-UV assay offers advantages over the traditional radioactivity assay in terms of safety and labor.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56060/1/1913_ftp.pd

    Synthesis of protein conjugates adsorbed on cationic liposomes surface

    Get PDF
    The well-known Toll like receptor 9 (TLR9) agonist CpG ODN has shown promising results as vaccine adjuvant in preclinical and clinical studies, however its in vivo stability and potential systemic toxicity remain a concern. In an effort to overcome these issues, different strategies have been explored including conjugation of CpG ODN with proteins or encapsulation/adsorption of CpG ODN into/onto liposomes. Although these methods have resulted in enhanced immunopotency compared to co-administration of free CpG ODN and antigen, we believe that this effect could be further improved. Here, we designed a novel delivery system of CpG ODN based on its conjugation to serve as anchor for liposomes. Thiol-maleimide chemistry was utilised to covalently ligate model protein with the CpG ODN TLR9 agonist. Due to its negative charge, the protein conjugate readily electrostatically bound cationic liposomes composed of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol and dimethyldioctadecylammonium bromide (DDA) in a very high degree. The novel cationic liposomes-protein conjugate complex shared similar vesicle characteristics (size and charge) compared to free liposomes. The conjugation of CpG ODN to protein in conjunction with adsorption on cationic liposomes, could promote co-delivery leading to the induction of immune response at low antigen and CpG ODN doses. ‱ The CpG ODN Toll-like receptor (TLR) 9 agonist was conjugated to protein antigens via thiol-maleimide chemistry. ‱ Due to their negative charge, protein conjugates readily electrostatically bound cationic liposomes composed of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol and dimethyldioctadecylammonium bromide (DDA) resulting to the design of novel cationic liposomes-protein conjugate complexes. ‱ The method is suited for the liposomal delivery of a variety of adjuvant-protein conjugates

    Determination of a Viral Load Threshold To Distinguish Symptomatic versus Asymptomatic Rotavirus Infection in a High-Disease-Burden African Population

    Get PDF
    We evaluated quantitative real-time PCR to establish the diagnosis of rotavirus gastroenteritis in a high-disease-burden population in Malawi using enzyme immunoassay as the gold standard diagnostic test. In 146 children with acute gastroenteritis and 65 asymptomatic children, we defined a cutoff point in the threshold cycle value (26.7) that predicts rotavirus-attributable gastroenteritis in this population. These data will inform the evaluation of direct and indirect rotavirus vaccine effects in Africa

    Point-of-Use Water Treatment and Use among Mothers in Malawi

    Get PDF
    A national household survey was conducted in Malawi to determine awareness and use of a socially marketed water treatment product. In all, 64% of mothers were aware of the product, and 7% were using it. Both poor and rural mothers had lower awareness and use rates. Targeting promotion to rural populations could enhance program effectiveness

    Endangered Archaeology in the Middle East and North Africa: Introducing the EAMENA Project

    Get PDF
    This project uses satellite imagery and historic aerial photographs to discover and interpret archaeological sites. It has created an open access database of archaeological records that provides basic information so that the sites can be better under- stood and preserved in the future. The threats to sites in the Middle East and North Africa are increasing and creating a record of previously unrecorded sites using this methodology may be our the last chance before they are destroyed

    The economic impact of childhood acute gastroenteritis on Malawian families and the healthcare system

    Get PDF
    OBJECTIVES: This prospective cohort study sought to estimate health system and household costs for episodes of diarrhoeal illness in Malawi. SETTING: Data were collected in two Malawian settings: a rural health centre in Chilumba and an urban tertiary care hospital in Blantyre. PARTICIPANTS: Children under 5 years of age presenting with diarrhoeal disease between 1 January 2013 and 21 November 2014 were eligible for inclusion. Illnesses attributed to other underlying causes were excluded, as were illnesses commencing more than 2 weeks prior to presentation. Complete data were collected on 514 cases at both the time of the initial visit to the participating healthcare facility and 6 weeks after discharge. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome measure was the total cost of an episode of illness. Costs to the health system were gathered from chart review (drugs and diagnostics) and actual hospital expenditure (staff and facility costs). Household costs, including lost income, were obtained by interview with the parents/guardians of patients. RESULTS: Total costs in 2014 USforruralinpatient,ruraloutpatient,urbaninpatientandurbanoutpatientwere for rural inpatient, rural outpatient, urban inpatient and urban outpatient were 65.33, 8.89,8.89, 60.23 and $14.51, respectively (excluding lost income). Mean household contributions to these costs were 15.8%, 9.8%, 21.3% and 50.6%. CONCLUSION: This study found significant financial burden from childhood diarrhoeal disease to the healthcare system and to households. The latter face the risk of consequent impoverishment, as the study demonstrates how the costs of seeking treatment bring the income of the majority of families in all income strata below the national poverty line in the month of illness

    Endangered Archaeology in the Middle East and North Africa: Introducing the EAMENA Project

    Get PDF
    This project uses satellite imagery and historic aerial photographs to discover and interpret archaeological sites. It has created an open access database of archaeological records that provides basic information so that the sites can be better under- stood and preserved in the future. The threats to sites in the Middle East and North Africa are increasing and creating a record of previously unrecorded sites using this methodology may be our the last chance before they are destroyed

    Effectiveness of a monovalent rotavirus vaccine in infants in Malawi after programmatic roll-out: an observational and case-control study

    Get PDF
    Background Rotavirus is the main cause of severe acute gastroenteritis in children in Africa. Monovalent human rotavirus vaccine (RV1) was added into Malawi's infant immunisation schedule on Oct 29, 2012. We aimed to assess the impact and effectiveness of RV1 on rotavirus gastroenteritis in the 2 years after introduction. Methods From Jan 1, 2012, to June 30, 2014, we recruited children younger than 5 years who were admitted into Queen Elizabeth Central Hospital, Blantyre, Malawi, with acute gastroenteritis. We assessed stool samples from these children for presence of rotavirus with use of ELISA and we genotyped rotaviruses with use of RT-PCR. We compared rotavirus detection rates in stool samples and incidence of hospital admittance for rotavirus in children from Jan 1 to June 30, in the year before vaccination (2012) with the same months in the 2 years after vaccination was introduced (2013 and 2014). In the case-control portion of our study, we recruited eligible rotavirus-positive children from the surveillance platform and calculated vaccine effectiveness (one minus the odds ratio of vaccination) by comparing infants with rotavirus gastroenteritis with infants who tested negative for rotavirus, and with community age-matched and neighbourhood-matched controls. Findings We enrolled 1431 children, from whom we obtained 1417 stool samples (99%). We detected rotavirus in 79 of 157 infants (50%) before the vaccine, compared with 57 of 219 (40%) and 52 of 170 (31%) in successive calendar years after vaccine introduction (p=0·0002). In the first half of 2012, incidence of rotavirus hospital admission was 269 per 100 000 infants compared with 284 in the same months of 2013 (rise of 5·8%, 95% CI −23·1 to 45·4; p=0·73) and 153 in these months in 2014 (a reduction from the prevaccine period of 43·2%, 18·0–60·7; p=0·003). We recruited 118 vaccine-eligible rotavirus cases (median age 8·9 months; IQR 6·6–11·1), 317 rotavirus-test-negative controls (9·4 months; 6·9–11·9), and 380 community controls (8·8 months; 6·5–11·1). Vaccine effectiveness for two doses of RV1 in rotavirus-negative individuals was 64% (95% CI 24–83) and community controls was 63% (23–83). The point estimate of effectiveness was higher against genotype G1 than against G2 and G12. Interpretation Routine use of RV1 reduced hospital admissions for several genotypes of rotavirus in children younger than 5 years, especially in infants younger than 1 year. Our data support introduction of rotavirus vaccination at the WHO recommended schedule, with continuing surveillance in high-mortality countries
    • 

    corecore