177 research outputs found

    Optimisation de l’implantation géophysique des forages en zone de socle au Nord du Burkina Faso

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     Cet article traite et analyse des données de prospection géophysique et de forage recueillies par le projet Eau et Environnement dans la région Nord du Burkina Faso. A partir de ce traitement, nous avons essayé d’identifier des critères pertinents en vue d’optimiser les conditions d’implantation de forages dans des zones difficiles comme celles du projet PEEN.  Ces critères ont été testés ; ils ont permis d’améliorer le taux de succès de plus de 10% et particulièrement dans les zones difficiles. Ce travail a aussi permis de donner quelques explications à des incohérences observées entre les épaisseurs d’altérations calculées à partir des résultats de sondages électriques et celles identifiées après le forage

    Leaf Eh and pH: A Novel Indicator of Plant Stress. Spatial, Temporal and Genotypic Variability in Rice (Oryza sativa L.)

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    A wealth of knowledge has been published in the last decade on redox regulations in plants. However, these works remained largely at cellular and organelle levels. Simple indicators of oxidative stress at the plant level are still missing. We developed a method for direct measurement of leaf Eh and pH, which revealed spatial, temporal, and genotypic variations in rice. Eh (redox potential) and Eh@pH7 (redox potential corrected to pH 7) of the last fully expanded leaf decreased after sunrise. Leaf Eh was high in the youngest leaf and in the oldest leaves, and minimum for the last fully expanded leaf. Leaf pH decreased from youngest to oldest leaves. The same gradients in Eh-pH were measured for various varieties, hydric conditions, and cropping seasons. Rice varieties differed in Eh, pH, and/or Eh@pH7. Leaf Eh increases and leaf pH decreases with plant age. These patterns and dynamics in leaf Eh-pH are in accordance with the pattern and dynamics of disease infections. Leaf Eh-pH can bring new insight on redox processes at plant level and is proposed as a novel indicator of plant stress/health. It could be used by agronomists, breeders, and pathologists to accelerate the development of crop cultivation methods leading to agroecological crop protection

    Encéphalopathie de Gayet-Wernicke compliquant des vomissements sur terrain de néoplasie colique

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    L'encéphalopathie de Gayet-Wernicke est une complication neuropsychiatrique aiguë secondaire à une carence en thiamine. Les vomissements incoercibles compliquant une obstruction intestinale chronique en sont une cause rare. Nous rapportons un cas d'encéphalopathie de Gayet-Wernicke compliquant des vomissements incoercibles sur terrain de néoplasie colique, chez une patiente de 60 ans

    Finite-size scaling analysis of the distributions of pseudo-critical temperatures in spin glasses

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    Using the results of large scale numerical simulations we study the probability distribution of the pseudo critical temperature for the three-dimensional Edwards-Anderson Ising spin glass and for the fully connected Sherrington-Kirkpatrick model. We find that the behavior of our data is nicely described by straightforward finite-size scaling relations.Comment: 23 pages, 9 figures. Version accepted for publication in J. Stat. Mec

    Центральна комісія національних меншин (ЦКНМ) при ВУЦВК та її місцеві органи. 1924 – 1934 рр.

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    We estimate the total land water storage (LWS) change between 2003 and 2013 using a global water mass budget approach. Hereby we compare the ocean mass change (estimated from GRACE space gravimetry on the one hand, and from the satellite altimetry-based global mean sea level corrected for steric effects on the other hand) to the sum of the main water mass components of the climate system: glaciers, Greenland and Antarctica ice sheets, atmospheric water and LWS (the latter being the unknown quantity to be estimated). For glaciers and ice sheets, we use published estimates of ice mass trends based on various types of observations covering different time spans between 2003 and 2013. From the mass budget equation, we derive a net LWS trend over the study period. The mean trend amounts to +0.30 +/- 0.18 mm/yr in sea level equivalent. This corresponds to a net decrease of 108 +/- 64 cu km/yr in LWS over the 2003-2013 decade. We also estimate the rate of change in LWS and find no significant acceleration over the study period. The computed mean global LWS trend over the study period is shown to be explained mainly by direct anthropogenic effects on land hydrology, i.e. the net effect of groundwater depletion and impoundment of water in man-made reservoirs, and to a lesser extent the effect of naturally-forced land hydrology variability. Our results compare well with independent estimates of human-induced changes in global land hydrology

    Theta Vectors and Quantum Theta Functions

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    In this paper, we clarify the relation between Manin's quantum theta function and Schwarz's theta vector in comparison with the kq representation, which is equivalent to the classical theta function, and the corresponding coordinate space wavefunction. We first explain the equivalence relation between the classical theta function and the kq representation in which the translation operators of the phase space are commuting. When the translation operators of the phase space are not commuting, then the kq representation is no more meaningful. We explain why Manin's quantum theta function obtained via algebra (quantum tori) valued inner product of the theta vector is a natural choice for quantum version of the classical theta function (kq representation). We then show that this approach holds for a more general theta vector with constant obtained from a holomorphic connection of constant curvature than the simple Gaussian one used in the Manin's construction. We further discuss the properties of the theta vector and of the quantum theta function, both of which have similar symmetry properties under translation.Comment: LaTeX 21 pages, give more explicit explanations for notions given in the tex

    Appendicular peritonitis in situs inversus totalis: a case report

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    <p>Abstract</p> <p>Introduction</p> <p><it>Situs inversus </it>is a congenital anomaly characterized by the transposition of the abdominal viscera. When associated with dextrocardia, it is known as <it>situs inversus totalis</it>. This condition is rare and can be a diagnostic problem when associated with appendicular peritonitis.</p> <p>Case presentation</p> <p>We report the case of a 20-year-old African man who presented to the emergency department with a 4-day history of diffuse abdominal pain, which began in his left iliac region and hypogastrium. After examination, we initiated a surgical exploration for peritonitis. We discovered a <it>situs inversus </it>at the left side of his liver, and his appendix was perforated in its middle third. A complementary post-operative thoracic and abdominal tomodensitometry revealed a <it>situs inversus totalis</it>.</p> <p>Conclusion</p> <p>Appendicular peritonitis in <it>situs inversus </it>is a rare association that can present a diagnostic problem. Morphologic exploration methods such as ultrasonography, tomodensitometry, magnetic resonance imaging, and laparoscopy may contribute to the early management of the disease and give guidance in choosing the most appropriate treatment for patients.</p

    Unravelling the effect of provitamin A enrichment on agronomic performance of tropical maize hybrids

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    Open Access JournalMaize is consumed in different traditional diets as a source of macro- and micro-nutrients across Africa. Significant investment has thus been made to develop maize with high provitamin A content to complement other interventions for alleviating vitamin A deficiencies. The current breeding focus on increasing β-carotene levels to develop biofortified maize may affect the synthesis of other beneficial carotenoids. The changes in carotenoid profiles, which are commonly affected by environmental factors, may also lead to a trade-off with agronomic performance. The present study was therefore conducted to evaluate provitamin A biofortified maize hybrids across diverse field environments. The results showed that the difference in accumulating provitamin A and other beneficial carotenoids across variable growing environments was mainly regulated by the genetic backgrounds of the hybrids. Many hybrids, accumulating more than 10 µg/g of provitamin A, produced higher grain yields (>3600 kg/ha) than the orange commercial maize hybrid (3051 kg/ha). These hybrids were also competitive, compared to the orange commercial maize hybrid, in accumulating lutein and zeaxanthins. Our study showed that breeding for enhanced provitamin A content had no adverse effect on grain yield in the biofortified hybrids evaluated in the regional trials. Furthermore, the results highlighted the possibility of developing broadly adapted hybrids containing high levels of beneficial carotenoids for commercialization in areas with variable maize growing conditions in Africa

    Performance of testers with contrasting provitamin A content to evaluate provitamin A maize for resistance to Aspergillus flavus infection and aflatoxin production

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    Open Access JournalIn sub-Saharan Africa (SSA), millions of people depend on maize as a primary staple. However, maize consumers in SSA may be exposed to malnutrition due to vitamin A deficiency (VAD) and unsafe aflatoxin levels, which can lead to serious economic and public health problems. Provitamin A (PVA) biofortified maize has been developed to alleviate VAD and may have additional benefits such as reduced aflatoxin contamination. In this study, maize inbred testers with contrasting PVA content in grain were used to identify inbred lines with desirable combining ability for breeding to enhance their level of resistance to aflatoxin. Kernels of 120 PVA hybrids generated by crossing 60 PVA inbreds with varying levels of PVA (5.4 to 51.7 µg/g) and two testers (low and high PVA, 14.4 and 25.0 µg/g, respectively) were inoculated with a highly toxigenic strain of Aspergillus flavus. Aflatoxin had a negative genetic correlation with β-carotene (r = −0.29, p 0.5). Eight inbreds had combined significant negative GCA effects for aflatoxin accumulation and spore count with significant positive GCA effects for PVA. Five testcrosses had combined significant negative SCA effects for aflatoxin with significant positive SCA effects for PVA. The high PVA tester had significant negative GCA effects for aflatoxin, lutein, β-carotene, and PVA. The study identified lines that can be used as parents to develop superior hybrids with high PVA and reduced aflatoxin accumulation. Overall, the results point out the importance of testers in maize breeding programs to develop materials that can contribute to controlling aflatoxin contamination and reducing VAD
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