226 research outputs found

    Importance of space and competition in optimizing genetic control strategies.

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    Advances in the genetic modification of organisms are creating new opportunities for the control of insect pests of both agriculture and public health significance. The timing and sex specificity of lethal transgene activation can be tailored to enhance the pest population control efficiency of mass-released, genetically modified insects. We developed mathematical models to determine the optimal timing and sex specificity of lethal transgene activation for the control of different types of pest population. We show that optimal release strategies are not only sensitive to the parameters governing growth of the population but also can be drastically affected by the inclusion of insect stage structuring, competition, and space. We emphasize the necessity of including these additional levels of complexity in future theoretical assessments as they are likely important considerations for designing transgenic organisms as well as their application in genetic control

    The Economic Importance of Draught Oxen on Small Farms in Namibia\u27s Eastern Caprivi Region

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    The main aim of this study was to analyse and document the value of smallholder farmers’ use of Draught Animal Power (DAP) systems in the Eastern Caprivi Region and to test the economic viability of DAP usage versus using tractors. This study applied Rapid Rural Appraisal techniques (RRA), including a survey. Semi-structured interviews were conducted with 312 farmers at their farms and data was gathered on the use of and economics related to the draught animal power system. Crop enterprise budgets, project reports, expert opinions and group discussions were analysed. The research found that the use of animal power performs better in terms of physical productivity per ha compared to tractor usage. Furthermore, agricultural production in Sibinda village area, with the use of oxen outperformed the other systems when it was evaluated with parametric analysis. From a financial perspective, faremrs in Sibinda and Linyanti using oxen ranked above their counterparts using tractors. Further, the exercise indicated that farmers are facing a multitude of challenges such as damage incurred from wild animals and high input costs. There were many difficulties facing the next generation in entering commericial agricultural production in Caprivi within the current cost-price squeeze environment. Therefore, understanding the role draught oxen power can play as a tool to increase the level of success for new farmers’ in agricultural production and management was noted

    Trend of Risk Components among Malaysian Stocks: Evidence from 2008 to 2014

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    This study examines the nature of risk among Malaysian stocks from January 2008 to July 2014.  The paper applies the concept of risk decomposition as stipulated by the single index model (SIM) in which the total risk is partitioned into two main components, i.e. systematic and unsystematic risks. Forty-five companies were randomly selected as the sample for this study. The results show that the unsystematic risk is greater than the systematic risk for all three different time periods used in the study. The level of both types of risk changed over the two sub-periods. The portion of systematic risk has decreased and the unsystematic risk component has increased considerably. This suggests the need for analysts and investors to focus on the company-specific factors when evaluating the risk associated with Malaysian stocks given the greater influence that the unsystematic risk has on total risk

    Effectiveness of a simple lymphoedema treatment regimen in podoconiosis management in southern Ethiopia: one year follow-up

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    Background: Podoconiosis is a non-filarial elephantiasis caused by long-term barefoot exposure to volcanic soils in endemic areas. Irritant silicate particles penetrate the skin, causing a progressive, debilitating lymphoedema of the lower leg, often starting in the second decade of life. A simple patient-led treatment approach appropriate for resource poor settings has been developed, comprising (1) education on aetiology and prevention of podoconiosis, (2) foot hygiene (daily washing with soap, water and an antiseptic), (3) the regular use of emollient, (4) elevation of the limb at night, and (5) emphasis on the consistent use of shoes and socks. Methodology/Principal Findings: We did a 12-month, non-comparative, longitudinal evaluation of 33 patients newly presenting to one clinic site of a non-government organization (the Mossy Foot Treatment & Prevention Association, MFTPA) in southern Ethiopia. Outcome measures used for the monitoring of disease progress were (1) the clinical staging system for podoconiosis, and (2) the Amharic Dermatology Life Quality Index (DLQI), both of which have been recently validated for use in this setting. Digital photographs were also taken at each visit. Twenty-seven patients completed follow up. Characteristics of patients completing follow-up were not significantly different to those not. Mean clinical stage and lower leg circumference decreased significantly (mean difference -0.67 (95% CI -0.38 to -0.96) and -2.00 (95% CI -1.26 to -2.74), respectively, p<0.001 for both changes). Mean DLQI diminished from 21 (out of a maximum of 30) to 6 (p<0.001). There was a non-significant change in proportion of patients with mossy lesions (p = 0.375). Conclusions/Significance: This simple, resource-appropriate regimen has a considerable impact both on clinical progression and self-reported quality of life of affected individuals. The regimen appears ideal for scaling up to other endemic regions in Ethiopia and internationally. We recommend that further research in the area include analysis of cost-effectiveness of the regimen

    Kajian Aspek Oseanografi Perairan Pada Kawasan Batu Lubang Pantai Distrik Makbon Kabupaten Sorong Papua Barat

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    Tujuan penelitian adalah untuk mengetahui karakteristik oseanografi perairan pada kawasan wisata Batu Lubang Pantai, Makbon, Sorong. Penelitian dilakukan pada Juli - Agustus 2021, di pesisir Kampung Batu Lubang Pantai, Makbon, Kab. Sorong, Papua barat. Analisis Data dilakukan dengan pengamatan menggunakan data dari Badan Informasi Geospasial (BIG), Ocean Color pada periode bulan Agustus-September 2021, serta dianalisis menggunakan Sistem Informasi Geografis (SIG). Hasil Penelitian diperoleh Kecepatan arus pada semua stasiun masih termasuk kategori baik dengan kisaran 0.012 - 1.024 m/s. Kecerahan perairan pada tiap stasiun termasuk kategori sesuai dan cukup baik dengan kisaran &gt;63.33 % hingga 74-80%. Persebaran suhu permukaan laut Batu Lubang Pantai berkisar antara 25 – 32 °C. Nilai di setiap stasiun masih dalam kisaran normal sebagai daerah tropis. Kedalaman perairan berkisar antara 0,30 – 5,27 m termasuk dalam kategori sangat sesuai untuk kegiatan pengembangan wisata pantai dengan batasan antara 3 hingga 6 meter. Untuk material dasar dengan kategori berpasir, berkarang dan lempung berpasir, termasuk dalam kategori lebih baik dan aman bagi pengunjung khususnya pada stasiun 1 dan 3. Untuk salinitas berada pada kisaran 33.4 – 34.5 ‰, dan tergolong normal. Pada parameter gelombang perairan berkisar antara 0.15 – 0.58 m, sedangkan untuk tinggi gelombang pada setiap stasiun berkisar antara 0.19 – 0.30 m. Ketinggian gelombang pada semua stasiun masih tergolong baik dan aman untuk kegiatan wisata pantai, dengan ketinggian gelombang yang aman bagi yaitu &lt;0,5 m. Untuk pasang surut berkisar antara 0.04 – 0.61 m dan termasuk dalam kategori pasang surut yang tidak terlalu besar yaitu antara 1-3 meter

    Development of a scale to measure stigma related to podoconiosis in Southern Ethiopia

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    Background: Health-related stigma adds to the physical and economic burdens experienced by people suffering from neglected tropical diseases (NTDs). Previous research into the NTD podoconiosis showed significant stigma towards those with the disease, yet no formal instrument exists by which to assess stigma or interventions to reduce stigma. We aimed to develop, pilot and validate scales to measure the extent of stigma towards podoconiosis among patients and in podoconiosis-endemic communities. Methods: Indicators of stigma were drawn from existing qualitative podoconiosis research and a literature review on measuring leprosy stigma. These were then formulated into items for questioning and evaluated through a Delphi process in which irrelevant items were discounted. The final items formed four scales measuring two distinct forms of stigma (felt stigma and enacted stigma) for those with podoconiosis and those without the disease. The scales were formatted as two questionnaires, one for podoconiosis patients and one for unaffected community members. 150 podoconiosis patients and 500 unaffected community members from Wolaita zone, Southern Ethiopia were selected through multistage random sampling to complete the questionnaires which were interview-administered. The scales were evaluated through reliability assessment, content and construct validity analysis of the items, factor analysis and internal consistency analysis. Results: All scales had Cronbach’s alpha over 0.7, indicating good consistency. The content and construct validity of the scales were satisfactory with modest correlation between items. There was significant correlation between the felt and enacted stigma scales among patients (Spearman’s r = 0.892; p < 0.001) and within the community (Spearman’s r = 0.794; p < 0.001). Conclusion: We report the development and testing of the first standardised measures of podoconiosis stigma. Although further research is needed to validate the scales in other contexts, we anticipate they will be useful in situational analysis and in designing, monitoring and evaluating interventions. The scales will enable an evidencebased approach to mitigating stigma which will enable implementation of more effective disease control and help break the cycle of poverty and NTDs

    Community-based control of a neglected tropical disease: the mossy foot treatment and prevention association

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    Podoconiosis (endemic non-filarial elephantiasis, also known as mossy foot) is a non-communicable disease now found exclusively in the tropics, caused by the conjunction of environmental, genetic, and economic factors. Silicate particles formed by the disintegration of lava in areas of high altitude (over 1,000 m) and seasonal rainfall (over 1,000 mm per annum) penetrate the skin of barefoot subsistence farmers, and in susceptible individuals cause lymphatic blockage and subsequent elephantiasis [1]. Although an estimated one million Ethiopians (of a total population of 77 million) are afflicted with podoconiosis [2], which creates a huge economic burden in endemic areas [3], no national policy has yet been developed to control or prevent the condition, and most affected communities remain unaware of treatment options

    Podoconiosis in East and West Gojam Zones, Northern Ethiopia

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    Background: Podoconiosis is a neglected tropical disease (NTD) that is prevalent in red clay soil-covered highlands of tropical Africa, Central and South America, and northern India. It is estimated that up to one million cases exist in Ethiopia. This study aimed to estimate the prevalence of podoconiosis in East and West Gojam Zones of Amhara Region in northern Ethiopia. Methodology/Principal Findings: A cross-sectional household survey was conducted in Debre Eliyas and Dembecha woredas (districts) in East and West Gojam Zones, respectively. The survey covered all 17,553 households in 20 kebeles (administrative subunits) randomly selected from the two woredas. A detailed structured interview was conducted on 1,704 cases of podoconiosis identified in the survey. Results: The prevalence of podoconiosis in the population aged 15 years and above was found to be 3.3% (95% CI, 3.2% to 3.6%). 87% of cases were in the economically active age group (15–64 years). On average, patients sought treatment five years after the start of the leg swelling. Most subjects had second (42.7%) or third (36.1%) clinical stage disease, 97.9% had mossy lesions, and 53% had open wounds. On average, patients had five episodes of acute adenolymphangitis (ALA) per year and spent a total of 90 days per year with ALA. The median age of first use of shoes and socks were 22 and 23 years, respectively. More men than women owned more than one pair of shoes (61.1% vs. 50.5%; x2 = 11.6 p = 0.001). At the time of interview, 23.6% of the respondents were barefoot, of whom about two-thirds were women. Conclusions: This study showed high prevalence of podoconiosis and associated morbidities such as ALA, mossy lesions and open wounds in northern Ethiopia. Predominance of cases at early clinical stage of podoconiosis indicates the potential for reversing the swelling and calls for disease prevention interventions

    Burden of podoconiosis in poor rural communities in Guliso woreda, western Ethiopia

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    Background. Podoconiosis is an environmental lymphoedema affecting people living and working barefoot on irritant red clay soil. Podoconiosis is relatively well described in southern Ethiopia, but remains neglected in other parts of the Ethiopian highlands. This study aimed to assess the burden of podoconiosis in rural communities in western Ethiopia. Methodology/Principal Findings. A cross-sectional study was conducted in Gulliso woreda (district), west Ethiopia. A household survey in the 26 rural kebeles (villages) of this district was conducted to identify podoconiosis patients and to measure disease prevalence. A more detailed study was done in six randomly selected kebeles to describe clinical features of the disease, patients’ experiences of foot hygiene, and shoe wearing practice. 1,935 cases of podoconiosis were registered, giving a prevalence of 2.8%. The prevalence was higher in those aged 15 – 64 years (5.2%) and in females than males (prevalence ratio 2.6:1). 90.3% of patients were in the 15 – 64 year age group. In the detailed study, 335 cases were interviewed and their feet assessed. The majority of patients were farmers, uneducated, and poor. Two-third of patients developed the disease before the age of thirty. Almost all patients (97.0%) had experienced adenolymphangitis (ALA - red, hot legs, swollen and painful groin) at least once during the previous year. Patients experienced an average of 5.5 ALA episodes annually, each of average 4.4 days, thus 24 working days were lost annually. The incidence of ALA in podoconiosis patients was higher than that reported for filariasis in other countries. Shoe wearing was limited mainly due to financial problems. Conclusions. We have documented high podoconiosis prevalence, frequent adenolymphangitis and high disease-related morbidity in west Ethiopia. Interventions must be developed to prevent, treat and control podoconiosis, one of the core neglected tropical diseases in Ethiopia

    Kajian Aspek Biologi Di Kawasan Wisata Batu Lubang Pantai Distrik Makbon Kabupaten Sorong Papua Barat

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    Pemanfaatan dan pengelolaan kawasan wisata untuk kegiatan wisata pantai yang baik harus didukung oleh data sumberdaya mengenai potensinya dari aspek biogeofisik, dengan salah satu aspek kajiannya adalah aspek biologi. Penelitian ini bertujuan mengidentifikasi kondisi aspek biologi di kawasan wisata Batu Lubang Pantai, Distrik Makbon, Kabupaten Sorong. Parameter biofisik yang dibahas antara lain kelimpahan fitoplankton, kandungan klorofil-a, kandungan bahan organik, dan fotosintesis. Analisis data yang digunakan berbasis Sistem Informasi Geografis (SIG). Hasil data dianalisis secara deskriptif kualitatifmenunjukan karakteristik biologidi kawasan wisata Batu lubang memiliki tingkat kesuburan perairan yang rendah, kandungan klorofil-a pada wilayah perairan Kampung Batu Lubang Pantai berkisar antara 0.0200 – 0.0230 mg/m³, kandungan bahan organik pada perairan Batu Lubang Pantai berkisar antara 40 – 51.4 mg/l, produktivitas primer pada perairan Batu Lubang Pantai berdasarkan nilai karbon yang dihasilkan pada proses fotosintesis berkisar antara 38.9 - 42.4 mgC/m³/hari, penutupan lahan berupa lahan terbuka, mangrove, dan pohon kelapa, serta biota Jenis biota yang berasosiasi di ekosistem pantai pada setiap stasiun terdiri dari beberapa kelompok hewan yang di temukan yaitu hewan kelompok Krustasea seperti kalomang/umang (Paguroidae) dari jenis Coenobita sp dan Kepiting (Brachyura) dari jenis Ocypode serta udang
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