20 research outputs found

    Mechanized tillage-induced compaction and its effect on maize (Zea Mays L.) growth and yield—a comprehensive review and analysis

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    While agricultural engineers are concerned with physico-mechanical properties of arable soils, agronomists tackle crop management husbandry as soil scientists’ dwell on bio-chemical properties. Such diverse and isolated interests seldom report any interaction or integrated effect of biological, agronomical, and physico-mechanical parameters of soils affected by mechanized tillage induced compaction. This paper reviews intrinsic effects of mechanized tillage-induced compaction on soil-water-nutrient dynamics, crop growth, and yield of maize. Mechanized tillage induced top and subsoil compaction are caused by soil-tyre contact stresses and machinery axle loads respectively. Mechanized tillage-induced compaction reduced maize nutrient absorption levels of Nitrogen (N), Potassium (K), Magnesium (Mg), and Sodium (Na) by 13.5%, 51.4%, 50.4% and 51.5% respectively. Maize N uptake was least affected by tillage-induced compaction compared to P and K. Mechanized tillage-induced compaction improved maize root intensity, root mass and volume by over 50% in compacted topsoils but decreased by 90% in the sublayers. Maize root length, fresh and dry root mass, shoot elongation, height, and leaf area index reduced by 29%, 39.1, 37.8, 27.1, 10-21, and 67.8% respectively. In contrast, mechanized tillage-induced compaction improved soil-seed-soil-root contacts, soil-root-bonding root density and diameter, stiffness, anchorage, and root-lodging resistance of maize. Mechanized tillage induced compaction index and bulk density range of 1.5-3.0MPa and 1.2-1.52 Mg/m3 respectively are the critical levels beyond which maize rooting, growth and yield are impaired. Dependent on dynamic soil covariates, viz limiting water range, matrix suction potential and organic matter content; mechanized tillage-induced compaction reduces maize yield by as high as 50%

    Small Sums, Big Impact: Corruption and Microfinance Institutions

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    Microfinance Institutions (MFIs) have been promoted worldwide as developmental platforms that can help eliminate some of the major global challenges such as poverty and economic development. The effectiveness of using MFIs to fulfill such expectations depends on their performance, which can be affected by a range of institutional factors such as corruption, rule of law and financial sector development. However, there is a lack of clarity on whether these factors are performance inhibitors or promoters. Using gender as a mediating factor, this study develops and tests these relationships on MFI performance, with the aim of contributing to research on institutions and corruption in the Global South. Drawing on the MFI performance model, the study uses data on MFIs operating in 33 African countries. The results reveal that the control of corruption reduces MFIs’ operating expenditure, while the control of corruption increases MFIs’ operating income. Drawing from the essentialist perspective of the theory of Social Construction of Gender, it is argued that female borrowers from MFIs are shown to have a mediating impact on the relationship between the variables tested (such as control of corruption) and MFI performance. The study also has public policy relevance for nations seeking to use MFIs as means of fostering entrepreneurship and economic development

    Small sums, big impact: corruption and microfinance institutions

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    Microfinance Institutions (MFIs) have been promoted worldwide as developmental platforms that can help eliminate some of the major global challenges such as poverty and economic development. The effectiveness of using MFIs to fulfil such expectations depends on their performance, which can be affected by a range of institutional factors such as corruption, rule of law and financial sector development. However, there is a lack of clarity on whether these factors are performance inhibitors or promoters. Using gender as a mediating factor, this study develops and tests these relationships on MFI performance, with the aim of contributing to research on institutions and corruption in the Global South. Drawing on the MFI performance model, the study uses data on MFIs operating in 33 African countries. The results reveal that the control of corruption reduces MFIs’ operating expenditure, while the control of corruption increases MFIs’ operating income. Drawing from the essentialist perspective of the theory of Social Construction of Gender, it is argued that female borrowers from MFIs are shown to have a mediating impact on the relationship between the variables tested (such as control of corruption) and MFI performance. The study also has public policy relevance for nations seeking to use MFIs as means of fostering entrepreneurship and economic development

    Culture-sensitive psychotraumatology

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    Background Although there is some evidence of the posttraumatic stress disorder (PTSD) construct’s cross cultural validity, trauma-related disorders may vary across cultures, and the same may be true for treatments that address such conditions. Experienced therapists tailor psychotherapy to each patient’s particular situation, to the nature of the patient’s psychopathology, to the stage of therapy, and so on. In addition, culture-sensitive psychotherapists try to understand how culture enhances the meaning of their patient’s life history, the cultural components of their illness and help-seeking behaviors, as well as their expectations with regard to treatment. We cannot take for granted that all treatment-seeking trauma survivors speak our language or share our cultural values. Therefore, we need to increase our cultural competencies. Methods The authors of this article are clinicians and/or researchers from across the globe, working with trauma survivors in various settings. Each author focused on one or more specific cultural aspects of working with trauma survivors and highlighted the following aspects. Results As a result of culture-specific individual and collective meanings linked to trauma and trauma-related disorders survivors may be exposed to (self-)stigma in the aftermath of trauma. Patients who are reluctant to talk about their traumatic experiences may instead be willing to write or use other ways of accessing the painful memories such as drawing. In other cultures, community and family cohesion are crucial elements of recovery. While awareness of culture-specific aspects is important, we also need to beware of premature cultural stereotyping.When disseminating empirically supported psychotherapies for PTSD across cultures, a number of additional challenges need to be taken into account: many low and middle income countries have very limited resources available and suffer from a poor health infrastructure. Conclusion In summary, culture-sensitive psychotraumatology means assuming an empathic and nonjudgmental attitude, trying to understand each individual’s cultural background.</p

    Viral shedding in patients infected with pandemic influenza A (H1N1) virus in Kenya, 2009

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    Understanding shedding patterns of 2009 pandemic influenza A (H1N1) (pH1N1) can inform recommendations about infection control measures. We evaluated the duration of pH1N1 virus shedding in patients in Nairobi, Kenya. Nasopharyngeal (NP) and oropharyngeal (OP) specimens were collected from consenting laboratory-confirmed pH1N1 cases every 2 days during October 14-November 25, 2009, and tested at the Centers for Diseases Control and Prevention-Kenya by real time reverse transcriptase polymerase chain reaction (rRT-PCR). A subset of rRT-PCR-positive samples was cultured. Of 285 NP/OP specimens from patients with acute respiratory illness, 140 (49%) tested positive for pH1N1 by rRT-PCR; 106 (76%) patients consented and were enrolled. The median age was 6 years (Range: 4 months-41 years); only two patients, both asthmatic, received oseltamivir. The median duration of pH1N1 detection after illness onset was 8 days (95% CI: 7-10 days) for rRT-PCR and 3 days (Range: 0-13 days) for viral isolation. Viable pH1N1 virus was isolated from 132/162 (81%) of rRT-PCR-positive specimens, which included 118/125 (94%) rRT-PCR-positive specimens collected on day 0-7 after symptoms onset. Viral RNA was detectable in 18 (17%) and virus isolated in 7/18 (39%) of specimens collected from patients after all their symptoms had resolved. In this cohort, pH1N1 was detected by rRT-PCR for a median of 8 days. There was a strong correlation between rRT-PCR results and virus isolation in the first week of illness. In some patients, pH1N1 virus was detectable after all their symptoms had resolved
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