285 research outputs found

    Differences in the epidemiology of theileriosis on smallholder dairy farms in contrasting agro-ecological and grazing strata of highland Kenya

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    A prospective cohort study was conducted in five purposively-sampled agro-ecological zone (AEZ)-grazing system strata in Murang’a District, Kenya, between March 1995 and June 1996. The study strata were selected based on a preliminary characterization study to represent the widest range of risks to East Coast fever (ECF) in the District and included zero-grazing and open-grazing farms. In total, 225 calves from 188 smallholder farms were examined from birth to 6 months of age and visited within the first 2 weeks of life and thereafter at bi-weekly intervals for up to 14 visits. The purpose of the study was to characterize the differences in epidemiology (risks of infection, morbidity and mortality) and potential control of ECF between the selected strata. Evidence of Theileria parva infection was assessed by increased antibody levels as measured in an indirect ELISA assay by the percent positivity (PP) of serum samples relative to a strong positive reference serum. Sero-conversion risks of T. parva were highest in the open-grazing strata. Antibody prevalence in adult cattle and ECF morbidity and mortality risks were also highest in open-grazing strata. While different, all five AEZ-grazing strata were considered to be endemically unstable for ECF. East Coast fever challenge was low in all zero-grazing strata and this challenge is likely to remain low due to continuing intensification of smallholder farming in the central highlands. In the open-grazing strata, there was higher challenge and a greater impact of ECF. ILRI publication no.: 99017

    Maternal micronutrient status and decreased growth of Zambian infants born during and after the maize price increases resulting from the southern African drought of 2001-2002.

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    OBJECTIVE: To investigate the effects on maternal micronutrient status and infant growth of the increased maize prices that resulted from the southern African drought of 2001-2002. DESIGN: Longitudinal cohort study. SETTING: A maternal and child health clinic in Lusaka, Zambia. SUBJECTS: Maternal and infant health and nutrition data and maternal plasma were being collected for a study of breast-feeding and postpartum health. Samples and data were analysed according to whether they were collected before (June to December 2001), during (January 2002 to April 2003) or after (May 2003 to January 2004) the period of increased maize price. Season and maternal HIV status were controlled for in analyses. RESULTS: Maize price increases were associated with decreased maternal plasma vitamin A during pregnancy (P = 0.028) and vitamin E postpartum (P = 0.042), with the lowest values among samples collected after May 2003 (vitamin A: 0.96 micromol l(-1), 95% confidence interval (CI) 0.84-1.09, n = 38; vitamin E: 30.8 micromol mmol(-1) triglycerides, 95% CI 27.2-34.8, n = 64) compared with before January 2002 (vitamin A: 1.03 micromol l(-1), 95% CI 0.93-1.12, n = 104; vitamin E: 38.9 micromol mmol(-1) triglycerides, 95% CI 34.5-43.8, n = 47). There were no significant effects of sampling date on maternal weight, haemoglobin or acute-phase proteins and only marginal effects on infant weight. Infant length at 6 and 16 weeks of age decreased progressively throughout the study (P-values for time of data collection were 0.51 at birth, 0.051 at 6 weeks and 0.026 at 16 weeks). CONCLUSIONS: The results show modest effects of the maize price increases on maternal micronutrient status. The most serious consequence of the price increases is likely to be the increased stunting among infants whose mothers experienced high maize prices while pregnant. During periods of food shortages it might be advisable to provide micronutrient supplements even to those who are less food-insecure

    Factors associated with non adherence to regulations on sale of alcohol by alcohol outlets operators in Thika Municipality, Kiambu County

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    Objective: To determine factors associated with non-adherence of existing alcohol regulations and policies on alcohol sale in Thika municipality Kiambu County.Design: A descriptive cross-sectional study.Setting: Thika Municipality, Kiambu County, KenyaSubjects: Eighty nine (89) participants were enrolled in the study. Ten (10) Key Informant Interviews were conducted among the security personnel, health officers, managers and supervisors.Results: Out of the 89 outlet operators enrolled in the study, (70.8%) among therespondents were not aware of the alcohol control act. Association between marital status and non adherence of the act was significant (p=0.003). There was low knowledge of 5.6%, who were aware of when the alcohol act was implemented, majority who totaled to 70.8% were not aware on when the alcohol control policy came into existence. Majority of the respondent 62.9% reported not to adhere to the alcohol control act of 2010; also the study showed that 57.3% of the responded were not aware of measures to control illicit brew. From the In-depth interviews most of the respondents interviewed confirmed that many of the operators were not aware of the act and it was difficult to implement thus subjecting the consumers into alcohol abuse. They also confirmed that with lack of employment, many women engaged into the alcohol operations which also contributed to the breakdown of their families given the mode of operations.Conclusion: This study concludes that there is failure in enforcement and adherence of the 2010 alcohol regulations. The study recommends the review of the alcohol control act of 2010 to ensure tough measures and penalties are adapted to anyone who fails to adhere to the act. Also there is need for awareness to be initiated to ensure members are informed and adhere to the policy. Setting up of an independent unit that will be mandated to enforcement and adherence of the 2010 alcoholic act

    Comparative Study of Different Stochastic Weather Generators for Long-Term Climate Data Simulation

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    Climate is one of the single most important factors affecting watershed ecosystems and water resources. The effect of climate variability and change has been studied extensively in some places; in many places, however, assessments are hampered by limited availability of long-term continuous climate data. Weather generators provide a means of synthesizing long-term climate data that can then be used in natural resource assessments. Given their potential, there is the need to evaluate the performance of the generators; in this study, three commonly used weather generators—CLImate GENerator (CLIGEN), Long Ashton Research Station Weather Generator (LARS-WG), and Weather Generators (WeaGETS) were compared with regard to their ability to capture the essential statistical characteristics of observed data (distribution, occurrence of wet and dry spells, number of snow days, growing season temperatures, and growing degree days). The study was based on observed 1966–2015 weather station data from the Western Lake Erie Basin (WLEB), from which 50 different realizations were generated, each spanning 50 years. Both CLIGEN and LARS-WG performed fairly well with respect to representing the statistical characteristics of observed precipitation and minimum and maximum temperatures, although CLIGEN tended to overestimate values at the extremes. This generator also overestimated dry sequences by 18%–30% and snow-day counts by 12%–19% when considered over the entire WLEB. It (CLIGEN) was, however, well able to simulate parameters specific to crop growth such as growing degree days and had an added advantage over the other generators in that it simulates a larger number of weather variables. LARS-WG overestimated wet sequence counts across the basin by 15%–38%. In addition, the optimal growth period simulated by LARS-WG also exceeded that obtained from observed data by 16%–29% basin-wide. Preliminary results with WeaGETS indicated that additional evaluation is needed to better define its parameters. Results provided insights into the suitability of both CLIGEN and LARS-WG for use with water resource applications

    Environment challenges in Africa: further dimensions to the trade, MNCs and energy debate

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    Purpose – The purpose of this paper is to examine the linkage between environmental challenges, multinational corporations (MNCs) activities, trade and energy in Africa; and further elaborate on the role of institutions, as an intervening variable. Design/methodology/approach – In this study, the authors extended the Environmental Kuznets Curve (EKC) model by including indicators of the presence of MNCs, trade and energy in the basic EKC model that has measures of environmental pollution (CO2), economic growth (gross domestic product per capita) and its squared value. The role of institutions was also considered and included as an inter-mediating variable. This model was tested on a sample of 27 African countries, for the period 1996-2010. The systems GMM was applied for the empirical analysis. This approach was aimed at circumventing the possibility of reverse causality and endogenous explanatory variables-such as institutions. Findings – Trade and MNCs’ activities may not have much contemporaneous impact on the environment. However, their lagged values have adverse and significant influence on the current values of environmental challenge. This implies that environmental policies regarding trade and MNCs require time response lag. Energy was significant only at contemporaneous value but not at its lagged value. Institutional development helps to suppress the negative excesses (like pollution) from the activities of trade, MNCs and energy, and consequently reduce environmental pollution. Originality/value – This paper included the role of institutions in the environmental pollution, trade, MNCs and energy debate. Empirical studies in this regard have inadvertently excluded this variable, but have, at best, included it as part of policy recommendations

    Beyond the Environmental Kuznets Curve in Africa: Evidence from Panel Cointegration

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    The main objective of this study is to establish the applicability of the environmental Kuznets curve (EKC) hypothesis in explaining the relationship between environmental pollution and development in Africa. The EKC has been used to explain such relationships in a variety of contexts, yet rarely applied in Africa, despite it hosting both the poorest countries in the world, 60% of those with extreme environmental pollution vulnerability and having a distinct socio-economic and institutional profile that tests the validity of such a model. This paper describes an empirical model that applies the EKC hypothesis and its modifications to 50 African countries, using data from 1995–2010. The empirical analysis suggests that there is a long-term relationship between CO2 and particulate matter emissions with per capita income and other variables, including institutional factors and trade, leading to specific recommendations on future strategies for sustainable development in an African context

    Fungal Infections among Diabetic Foot Ulcer- Patients Attending Diabetic Clinic in Kenyatta National Hospital, Kenya

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    Objective: To isolate and identify fungal pathogens associated with dermatophytoses in diabetic patients and identify the spectrum of yeasts colonising diabetic foot ulcers at Kenyatta National Hospital.Design: A cross sectional Laboratory based study.Setting: The Kenyatta National Hospital diabetic clinic.Subjects: Sixty one patients with diabetic foot ulcers from August to November 2009.Results: The five most occurring pathogens were Biopolaris hawaiiensis (5.5%), Trichophyton schoenleinii (3.7%), Aspergillus niger (3.0%), Trichophyton rubrum (3.0%), Fusarium oxysporum (3.0%). Other moulds accounted for less than 3.0%. One suspected case (0.6%) of Penicilium marneffei was isolated although it could not be ascertained due to its high containment requirement. Among the dermatophytes, the most occurring mould was Trichophyton schoenleinii (3.7%) while in non-dermatophyte was Biopolaris hawaiiensis (5.5%). Eight pathogenic yeasts were identified with C. parapsilosis (6.1 %) being the most common followed by C. famata (3.0%). Fungal infestation was highest in callus formation (78.6%).Conclusion: Fungal aetiological agents are significant cause of diabetic wound infection and may require antifungal intervention for successful management of diabetic foot ulcers

    A review on DC collection grids for offshore wind farms with HVDC transmission system

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    Abstract: Traditionally, the internal network composition of offshore wind farms consists of alternating current (AC) collection grid; all outputs of wind energy conversion units (WECUs) on a wind farm are aggregated to an AC bus. Each WECU includes: a wind-turbine plus mechanical parts, a generator including electronic controller, and a huge 50-or 60-Hz power transformer. For a DC collection grid, all outputs of WECUs are aggregated to a DC bus; consequently, the transformer in each WECU is replaced by a power converter or rectifier. The converter is more compact and smaller in size compared to the transformer. Thus reducing the size and weight of the WECUs, and also simplifying the wind farm structure. Actually, the use of offshore AC collection grids instead of offshore DC collection grids is mainly motivated by the availability of control and protection devices. However, efficient solutions to control and protect DC grids including HVDC transmission systems have already been addressed. Presently, there are no operational wind farms with DC collection grids, only theoretical and small-scale prototypes are being investigated worldwide. Therefore, a suitable configuration of the DC collection grid, which has been practically verified, is not available yet. This paper discussed some of the main components required for a DC collection grid including: the wind-turbine-generator models, the control and protection methods, the offshore platform structure, and the DC-grid feeder configurations. The key component of a DC collection grid is the power converter; therefore, the paper also reviews some topologies of power converter suitable for DC grid applications
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