Annihilation Diagrams in Two-Body Nonleptonic Decays of Charmed Mesons

In the pole-dominance model for the two-body nonleptonic decays of charmed mesons $D \rightarrow PV$ and $D \rightarrow VV$, it is shown that the contributions of the intermediate pseudoscalar and the axial-vector meson poles cancel each other in the annihilation diagrams in the chiral limit. In the same limit, the annihilation diagrams for the $D \rightarrow PP$ decays vanish independently.Comment: 9 pages (+ 3 figures available upon request), UR-1316, ER-40685-766, IC/93/21

A Wet Excavation Method for Root/Shoot Studies of Pearl Millet on the Sandy Soils of the Sahel

Root/shoot relations of two cultivars of pearl millet (Pennisetum glaucum) were studied on a sandy soil at Sadore in Niger using a wet excavation method. For the first 10 days after emergence (DAE), the length of the seminal root showed an exponential growth rate while plant height increased more or less linearly. The maximum rooting depth for millet was 168 cm and the maximum number of root axes and primary laterals, 172 per plant. Root length continued to increase up to 75 DAE, the maximum length exceeding 5000 cm per plant. The proportion of total day matter accumulated in the roots decreased from 30% in the early stages to less than 20% by maturity. The wet excavation method is a promising technique for the rapid removal of intact root systems of pearl millet from the sandy soils of the Sahel

Effect of year and fertilizer on water-use efficiency of pearl millet (Pennisetum glaucum) in Niger

A comprehensive study was conducted over a 4-year period (1984-87) to evaluate the water use, growth and yield responses of pearl millet (Pennisetum glaucum) cv. CIVT grown with or without fertilizer (30 kg P2O5 and 45 kg N ha-1) at the ICRISAT Sahelian Centre, Sadore, Niger. Significant year and fertilizer effects on the growth and yield of millet were observed. Observed year effects were primarily due to the variations in the amount and distribution of rainfall in relation to the potential demand for water. During 1984, 1985 and 1987, total rainfall was below the long term average, while in 1986 it was above average. While the onset of rains (relative to the average date of onset) was early from 1984 to 1986, in 1987 the sowings were delayed by as much as 33 days. Of all the four years, the separation between the treatments in the cumulative evaporation was most evident for 1984, which was a drought year with below-average rainfall in all the months from June to September. Cumulative evaporation patterns in 1985 and 1986 were similar because of regular rains and high average rainfall per rainy day from June to October. In 1987, sowings were delayed until 15 July and only 6.9 mm of rainfall was received per rainy day in July. Hence cumulative evaporation was initially low and showed a significant increase only after two significant rain events in early August. There was a large response to fertilizer in all the years as small additions of fertilizer phosphate increased the soluble phosphate in the soil. Fertilizer application resulted in a small increase in water use (7-14 %) in all years except 1987. Increased yield due to the application of fertilizer was accompanied by an increase in the water-use efficiency (WUE) in all the four years with the largest increase in 1985. The beneficial effect of fertilizers could be attributed to the rapid early growth of leaves which can contribute to reduction of soil evaporative losses and increased WUE. Over the four seasons, average increase in the WUE due to the addition of fertilizer was 84

Rifampicin mono-resistant tuberculosis is not the same as multidrug-resistant tuberculosis: a descriptive study from Khayelitsha, South Africa

Rifampicin mono-resistant TB (RMR-TB, rifampicin resistance and isoniazid susceptibility) constitutes 38% of all rifampicin-resistant TB (RR-TB) in South Africa and is increasing. We aimed to compare RMR-TB with multidrug-resistant TB (MDR-TB) within a high TB, RR-TB and HIV burden setting. Patient-level clinical data and stored RR-TB isolates from 2008-2017 with available whole genome sequencing (WGS) data were used to describe risk factors associated with RMR-TB and to compare rifampicin-resistance (RR) conferring mutations between RMR-TB and MDR-TB. A subset of isolates with particular RR-conferring mutations were subjected to semi-quantitative rifampicin phenotypic drug susceptibility testing. Among 2,041 routinely diagnosed RR-TB patients, 463 (22.7%) had RMR-TB. HIV-positive individuals (adjusted Odds Ratio 1.4, 95% CI 1.1-1.9) and diagnosis between 2013-2017 versus 2008-2012 (aOR 1.3, 1.1-1.7) were associated with RMR-TB. Among 1,119 (54.8%) patients with available WGS data showing RR-TB, significant differences in the distribution of rpoB RR-conferring mutations between RMR-TB and MDR-TB isolates were observed. Mutations associated with high-level RR were more commonly found among MDR-TB isolates (811/889, 90.2% versus 162/230, 70.4% among RMR-TB, p<0.0001). In particular, the rpoB L430P mutation, conferring low-level RR, was identified in 32/230 (13.9%) RMR-TB versus 10/889 (1.1%) in MDR-TB (p<0.0001). Among 10 isolates with an rpoB L430P mutation, 7 were phenotypically susceptible using the critical concentration of 0.5 mug/ml (range 0.125-1 mug/ml). The majority (215/230, 93.5%) of RMR-TB isolates showed susceptibility to all other TB drugs, highlighting the potential benefits of WGS for simplified treatment. These data suggest that the evolution of RMR-TB differs from MDR-TB with a potential contribution from HIV infection

Potential contribution of HIV during first-line tuberculosis treatment to subsequent rifampicin-monoresistant tuberculosis and acquired tuberculosis drug resistance in South Africa: a retrospective molecular epidemiology study

Background: South Africa has a high burden of rifampicin-resistant tuberculosis (including multidrug-resistant [MDR] tuberculosis), with increasing rifampicin-monoresistant (RMR) tuberculosis over time. Resistance acquisition during first-line tuberculosis treatment could be a key contributor to this burden, and HIV might increase the risk of acquiring rifampicin resistance. We assessed whether HIV during previous treatment was associated with RMR tuberculosis and resistance acquisition among a retrospective cohort of patients with MDR or rifampicin-resistant tuberculosis. Methods: In this retrospective cohort study, we included all patients routinely diagnosed with MDR or rifampicin-resistant tuberculosis in Khayelitsha, Cape Town, South Africa, between Jan 1, 2008, and Dec 31, 2017. Patient-level data were obtained from a prospective database, complemented by data on previous tuberculosis treatment and HIV from a provincial health data exchange. Stored MDR or rifampicin-resistant tuberculosis isolates from patients underwent whole-genome sequencing (WGS). WGS data were used to infer resistance acquisition versus transmission, by identifying genomically unique isolates (single nucleotide polymorphism threshold of five). Logistic regression analyses were used to assess factors associated with RMR tuberculosis and genomic uniqueness. Findings: The cohort included 2041 patients diagnosed with MDR or rifampicin-resistant tuberculosis between Jan 1, 2008, and Dec 31, 2017; of those, 463 (22.7%) with RMR tuberculosis and 1354 (66.3%) with previous tuberculosis treatment. In previously treated patients, HIV positivity during previous tuberculosis treatment versus HIV negativity (adjusted odds ratio [OR] 2.07, 95% CI 1.35-3.18), and three or more previous tuberculosis treatment episodes versus one (1.96, 1.21-3.17) were associated with RMR tuberculosis. WGS data showing MDR or rifampicin-resistant tuberculosis were available for 1169 patients; 360 (30.8%) isolates were identified as unique. In previously treated patients, RMR tuberculosis versus MDR tuberculosis (adjusted OR 4.96, 3.40-7.23), HIV positivity during previous tuberculosis treatment (1.71, 1.03-2.84), and diagnosis in 2013-17 (1.42, 1.02-1.99) versus 2008-12, were associated with uniqueness. In previously treated patients with RMR tuberculosis, HIV positivity during previous treatment (adjusted OR 5.13, 1.61-16.32) was associated with uniqueness as was female sex (2.50 [1.18-5.26]). Interpretation: These data suggest that HIV contributes to rifampicin-resistance acquisition during first-line tuberculosis treatment and that this might be driving increasing RMR tuberculosis over time. Large-scale prospective cohort studies are required to further quantify this risk. Funding: Swiss National Science Foundation, South African National Research Foundation, and Wellcome Trust

Wrong schools or wrong students? The potential role of medical education in regional imbalances of the health workforce in the United Republic of Tanzania

<p>Abstract</p> <p>Background</p> <p>The United Republic of Tanzania, like many other countries in sub-Saharan Africa, faces a human resources crisis in its health sector, with a small and inequitably distributed health workforce. Rural areas and other poor regions are characterised by a high burden of disease compared to other regions of the country. At the same time, these areas are poorly supplied with human resources compared to urban areas, a reflection of the situation in the whole of Sub-Saharan Africa, where 1.3% of the world's health workforce shoulders 25% of the world's burden of disease. Medical schools select candidates for training and form these candidates' professional morale. It is therefore likely that medical schools can play an important role in the problem of geographical imbalance of doctors in the United Republic of Tanzania.</p> <p>Methods</p> <p>This paper reviews available research evidence that links medical students' characteristics with human resource imbalances and the contribution of medical schools in perpetuating an inequitable distribution of the health workforce.</p> <p>Existing literature on the determinants of the geographical imbalance of clinicians, with a special focus on the role of medical schools, is reviewed. In addition, structured questionnaires collecting data on demographics, rural experience, working preferences and motivational aspects were administered to 130 fifth-year medical students at the medical faculties of MUCHS (University of Dar es Salaam), HKMU (Dar es Salaam) and KCMC (Tumaini University, Moshi campus) in the United Republic of Tanzania. The 130 students represented 95.6% of the Tanzanian finalists in 2005. Finally, we apply probit regressions in STATA to analyse the cross-sectional data coming from the aforementioned survey.</p> <p>Results</p> <p>The lack of a primary interest in medicine among medical school entrants, biases in recruitment, the absence of rural related clinical curricula in medical schools, and a preference for specialisation not available in rural areas are among the main obstacles for building a motivated health workforce which can help correct the inequitable distribution of doctors in the United Republic of Tanzania.</p> <p>Conclusion</p> <p>This study suggests that there is a need to re-examine medical school admission policies and practices.</p

Sustainability performance model: a case study of pneumatic nipple hose connector

Sustainability concept was first introduced by Dr Harlem Brundtland in 1980’s promoting the need to preserve today’s mother nature for the sake of our future generations. There are three main evaluation criteria’s involved in sustainability approach namely economics, environmental and social. In consumer product manufacturing industry, the economics criteria are measured by consider the total manufacturing costs where it evaluates the economic sustainability of a company in a long term. The impact to the environment during manufacturing process can be used to measure the environment criteria. The social criteria are complicated to evaluate. But focusing at production line workers’ health who works at the production line can be used to evaluate the social criteria because it gives direct impact to their performance. In this paper, the sustainability concept is applied at the production line in the production of a pneumatic nipple hose connector. The evaluation criteria which has been considered are total manufacturing costs, environmental impact, ergonomics impact and also energy used for manufacturing. This study involves machine learning optimization by using neural network model which carried out in two stages. The first stage is to predict the results based on experimental works. The second stage is by using inversed neural network model to determine the optimum cutting parameters so that it can be used to manufacture the pneumatic nipple hose connector. Through these stages, optimization of the manufacturing procedures to produce pneumatic nipple hose connector already considered the criteria for sustainability