2,964 research outputs found

    A Long History of Low Productivity in Zambia: Is it Time to Do Away with Blanket Recommendations?

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    Although there have been calls to ramp up efforts to design and implement a fertiliser programme that recognises the spatial variability of soil fertility and climatic conditions in the country, Zambia like most countries in Africa, continues to rely heavily on outdated general fertiliser recommendations, which are uniform across geographic locations and crops. This could be one of the main reasons why Zambia continues to record low crop productivity despite government fertilizer subsidy programmes. Using soil analysis and household data collected in rural Zambia, this study presents a comparative analysis of location-specific fertilizer application versus blanket recommendation to demonstrate why it is important for the Zambian government to invest in area-specific fertiliser recommendations in order to raise crop productivity. As expected, the results show that soil fertility varies across the country. This was observed in all the mapped soil properties with ranges of 2.7 to 7.8 for soil pH, 0.08% to 10.1% for soil organic carbon and 1.0 ppm to 333.6ppm for soil Phosphorus. These values belong to different classes in terms of acidities and levels of adequacy and deficiency. These results indicate that blanket fertiliser recommendations, or even liming, may not be well suited across the entire country. Instead, they support the need for Zambia to promote area-specific fertiliser recommendations. It is recommended that soil testing be promoted as part of extension messages, and that the government’s Farmer Input Support Programme (FISP) should consider including soil testing as a requirement for the subsidy

    A Long History of Low Productivity in Zambia: Is it Time to Do Away with Blanket Recommendations?

    Get PDF
    Although there have been calls to ramp up efforts to design and implement a fertiliser programme that recognises the spatial variability of soil fertility and climatic conditions in the country, Zambia like most countries in Africa, continues to rely heavily on outdated general fertiliser recommendations, which are uniform across geographic locations and crops. This could be one of the main reasons why Zambia continues to record low crop productivity despite government fertilizer subsidy programmes. Using soil analysis and household data collected in rural Zambia, this study presents a comparative analysis of location-specific fertilizer application versus blanket recommendation to demonstrate why it is important for the Zambian government to invest in area-specific fertiliser recommendations in order to raise crop productivity. As expected, the results show that soil fertility varies across the country. This was observed in all the mapped soil properties with ranges of 2.7 to 7.8 for soil pH, 0.08% to 10.1% for soil organic carbon and 1.0 ppm to 333.6ppm for soil Phosphorus. These values belong to different classes in terms of acidities and levels of adequacy and deficiency. These results indicate that blanket fertiliser recommendations, or even liming, may not be well suited across the entire country. Instead, they support the need for Zambia to promote area-specific fertiliser recommendations. It is recommended that soil testing be promoted as part of extension messages, and that the government’s Farmer Input Support Programme (FISP) should consider including soil testing as a requirement for the subsidy

    Case Study of a Water Tank Behaviour on an Improved Collapsible Soil

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    The geotechnical report performed for the design stage of a water tank revealed a soil profile consisting in a thick layer of collapsible/loessial soil. The paper firstly presents the complex characterization of the natural ground conditions before and after the soil cushion performance, during the water filling tests of the tank. Specific charts are presented to emphasize the physical and mechanical parameter differences of the natural and improved ground by the soil cushion. The prediction of the supplementary settlement profile on the construction site of the water tank has been performed due to a significant water leakage from the tank during the filling tests, and thus endangering the tank stability and serviceability. Charts presenting the soil-tank interaction during service are included together with settlement diagrams related to potential water leakage from the tank. The paper presents in the second part the stress and strain states that have been comparatively analyzed for various moistening hypotheses with different risk level, according to the settlement increase based on the up going of the moistening front

    Taylor dispersion with absorbing boundaries: A Stochastic Approach

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    We describe how to solve the problem of Taylor dispersion in the presence of absorbing boundaries using an exact stochastic formulation. In addition to providing a clear stochastic picture of Taylor dispersion, our method leads to closed-form expressions for all the moments of the convective displacement of the dispersing particles in terms of the transverse diffusion eigenmodes. We also find that the cumulants grow asymptotically linearly with time, ensuring a Gaussian distribution in the long-time limit. As a demonstration of the technique, the first two longitudinal cumulants (yielding respectively the effective velocity and the Taylor diffusion constant) as well as the skewness (a measure of the deviation from normality) are calculated for fluid flow in the parallel plate geometry. We find that the effective velocity and the skewness (which is negative in this case) are enhanced while Taylor dispersion is suppressed due to absorption at the boundary.Comment: 4 pages, 1 figur

    Liver procurement as part of multiple organ procurement

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    Departamentul de Chirurgie Generală şi Transplant Hepatic “Dan Setlacec”, Institutul Clinic Fundeni, Bucureşti, România, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Scop: Prelevarea hepatică, etapă premergătoare transplantului hepatic, parte din prelevarea multiorgan, contribuie prin acuratețea și corectitudinea intervenției la obținerea unei grefe hepatice de bună calitate cu rezultate bune ale transplantului atît imediate cât și pe termen lung. Lucrarea de față își propune să evidențieze importantul rol al identificării variantelor anatomice și adaptarea metodelor de prelevare în funcție de acestea.Material şi metode: Pe parcursul perioadei 1 ianuarie 2000-16 iunie 2015 s-au efectuat în Centrul nostru 666 prelevări multiorgan. O importanță deosebită a fost acordată recunoașterii variantelor anatomice arteriale, acestea adaugând un grad de dificultate procedurii, dar fiind totodată esențiale pentru asigurarea succesului intervenției. Rezultate: Caracteristicile heterogene ale donatorilor au obligat la aplicarea unei game variate de tehnici de prelevare, adaptate fiecărei situații, așa cum au fost descrise în lucrarea de față, un pas cheie pentru obținerea unei grefe viabile pentru transplant. Concluzii: Multiplele tehnici de prelevare hepatică pot fi aplicate cu succes când sunt adaptate fiecarui donator, scurtând timpul de prelevare și furnizând o grefă de cea mai bună calitate.Purpose: Liver procurement, the preliminary stage of liver transplantation, is a part of multi-organ procurement, and it contributes, with its accuracy and correctness to the high quality liver graft, with the best results in the transplantation process (both immediate and long term). This paper is framed to enlighten the important role of identification of anatomical variants and the selection of the procurement technique that suits most. Material and methods: During 1st Jan 2000-16th Jun 2015 a number of 666 multi-organ procurements were performed in our center. A special attention was paid in recognizing of anatomical variants of blood vessels (especially arterial blood vessels), which added a high degree of difficulty to the procedures, but was considered to be vital in order to ensure the success of the intervention. Results: Heterogeneous characteristics of donors imposed the implementation of a variety of sampling techniques, adapted on each situation as was described in the paper, an essential step to obtain a viable liver / organ graft suitable for the transplant. Conclusions: The multiple methods of liver procurement can be successfully applied when it is adapted to each of the donors, thus shortening the actual time of the liver harvesting, delivering the best quality of the new liver graft

    No multi-graviton theories in the presence of a Dirac field

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    The cross-couplings among several massless spin-two fields (described in the free limit by a sum of Pauli-Fierz actions) in the presence of a Dirac field are investigated in the framework of the deformation theory based on local BRST cohomology. Under the hypotheses of locality, smoothness of the interactions in the coupling constant, Poincare invariance, (background) Lorentz invariance and the preservation of the number of derivatives on each field, we prove that there are no consistent cross-interactions among different gravitons in the presence of a Dirac field. The basic features of the couplings between a single Pauli-Fierz field and a Dirac field are also emphasized.Comment: 48 page

    The WHO global tuberculosis 2021 report - not so good news and turning the tide back to end TB

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    Objective: To review the data presented in the 2021 WHO global TB report and discuss the current constraints in the global response. Introduction and methods: The WHO global TB reports, consolidate TB data from countries and provide up to date assessment of the global TB epidemic. We reviewed the data presented in the 2021 report. Results: We noted that the 2021 WHO global TB report presents a rather grim picture on the trajectory of the global epidemic of TB including a stagnation in the annual decline in TB incidence, a decline in TB notifications and an increase in estimated TB deaths. All the targets set at the 2018 United Nations High Level Meeting on TB were off track. Interpretation and conclusion: The sub-optimal global performance on achieving TB control targets in 2020 is attributed to the on-going COVID-19 pandemic, however, TB programs were already off track well before the onset of the pandemic, suggesting that the pandemic amplified an already fragile global TB response. We emphasize that ending the global TB epidemic will require bold leadership, optimization of existing interventions, widespread coverage, addressing social determinants of TB and importantly mobilization of adequate funding required for TB care and preventio

    Ultra High Energy Cosmology with POLARBEAR

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    Observations of the temperature anisotropy of the Cosmic Microwave Background (CMB) lend support to an inflationary origin of the universe, yet no direct evidence verifying inflation exists. Many current experiments are focussing on the CMB's polarization anisotropy, specifically its curl component (called "B-mode" polarization), which remains undetected. The inflationary paradigm predicts the existence of a primordial gravitational wave background that imprints a unique B-mode signature on the CMB's polarization at large angular scales. The CMB B-mode signal also encodes gravitational lensing information at smaller angular scales, bearing the imprint of cosmological large scale structures (LSS) which in turn may elucidate the properties of cosmological neutrinos. The quest for detection of these signals; each of which is orders of magnitude smaller than the CMB temperature anisotropy signal, has motivated the development of background-limited detectors with precise control of systematic effects. The POLARBEAR experiment is designed to perform a deep search for the signature of gravitational waves from inflation and to characterize lensing of the CMB by LSS. POLARBEAR is a 3.5 meter ground-based telescope with 3.8 arcminute angular resolution at 150 GHz. At the heart of the POLARBEAR receiver is an array featuring 1274 antenna-coupled superconducting transition edge sensor (TES) bolometers cooled to 0.25 Kelvin. POLARBEAR is designed to reach a tensor-to-scalar ratio of 0.025 after two years of observation -- more than an order of magnitude improvement over the current best results, which would test physics at energies near the GUT scale. POLARBEAR had an engineering run in the Inyo Mountains of Eastern California in 2010 and will begin observations in the Atacama Desert in Chile in 2011.Comment: 8 pages, 6 figures, DPF 2011 conference proceeding

    A competitive sensing system based on cyclobis(paraquat-p-phenylene) and a new β-cyclodextrin-tetrathiafulvalene derivative

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    We report the synthesis of 4,5-di(ethylthio)-4′-[6-deoxy-β-cyclodextrin-6-yl-aminocarbonyl]-tetrathiafulvalene (β-CD-DET-TTF) and its inclusion abilities towards cyclobis(paraquat-p-phenylene) (CBPQT4+ ) and 1-naphthol. The structure of the synthesised compound has been established by mass spectrometry and 1H NMR spectra combined with a theoretical MM3 and AM1 study. The sensor affords a charge transfer (CT) complex with the CBPQT4+ and is able to include 1-naphthol in the cyclodextrin cavity. The complexes were characterised experimentally by UV–vis spectroscopy and simulated by a MM3 docking procedure. The sensing ability of the β-CD-DET-TTF/CBPQT4+ complex towards 1-naphthol has been investigated by a competitive spectral method. The synthesis and characterisation of a new water soluble β-CD-DET-TTF derivative able to formed a CT complex with the CBPQT4+ acceptor is reported. The water soluble CT complex β-CD-DET-TTF/CBPQT4+ could be used as an efficient sensor towards aromatic guests prone to give inclusion complexes with the CBPQT4+ ring
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