566 research outputs found

    Variations in agronomic and grain quality traits of rice grown under irrigated lowland conditions in West Africa

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    Rice breeding in West Africa has been largely skewed toward yield enhancement and stress tolerance. This has led to the variable grain quality of locally produced rice in the region. This study sought to assess variations in the agronomic and grain quality traits of some rice varieties grown in this region, with a view to identifying sources of high grain yield and quality that could serve as potential donors in their breeding programs. Forty‐five varieties were grown under irrigated conditions in Benin and Senegal with two trials in each country. There were wide variations in agronomic and grain quality traits among the varieties across the trials. Cluster analysis using paddy yield, head rice yield, and chalkiness revealed that 68% of the total variation could be explained by five varietal groupings. One group comprising seven varieties (Afrihikari, BG90‐2, IR64, Sahel 108, WAT311‐WAS‐B‐B‐23‐7‐1, WAT339‐TGR‐5‐2, and WITA 10) had high head rice yield and low chalkiness. Of the varieties in this group, Sahel 108 had the highest paddy yield in three of the four trials. IR64 and Afrihikari had intermediate and low amylose content, respectively, with the rest being high‐amylose varieties. Another group of varieties consisting of B6144F‐MR‐6‐0‐0, C74, IR31851‐96‐2‐3‐2‐1, ITA222, Jaya, Sahel 305, WITA 1, and WITA 2 had high paddy yield but poor head rice yield and chalkiness. The use of materials from these two groups of varieties could accelerate breeding for high yielding rice varieties with better grain quality for local production in West Africa

    Aménagements hydro-agricoles et santé (vallée du fleuve Sénégal)

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    Près de 1 500 personnes résidant dans les villages rattachés au périmètre irrigué MO 6bis (périmètre de Diomandou, département de Podor) ont fait l'objet de prélèvements d'urine et/ou de selle afin de déterminer la prévalence de la bilharziose urinaire, de la bilharziose intestinale ainsi que des autres parasitoses entériques. Chez les riverains du périmètre, 1 295 urines ont été examinées, parmi lesquelles sept contenaient des oeufs viables de #Schistosoma haematobium,cequirepreˊsenteuntauxdepreˊvalencede0,5, ce qui représente un taux de prévalence de 0,5%. L'enquête épidémiologique a montré qu'il s'agissait de cas importés. Les examens de selles ont concerné 1 181 sujets. 316 d'entre eux (soit plus de 26% des personnes examinées) hébergeaient un ou plusieurs parasites intestinaux. Un seul éliminait des oeufs de #S. mansoni, ce qui correspond à un indice d'infestation de 0,1%. Il s'agissait là aussi d'un individu dont la contamination avait eu lieu en dehors de la zone d'étude. #Eschirichia coliestlaparasiteenteˊriqueleplusreˊpanduavec17,2 est la parasite entérique le plus répandu avec 17,2% de porteurs de kystes. Les autres espèces rencontrées, à savoir #Hymenolepis nana, #Strongyloïdes stercoralis, #Ascaris lumbricoïdes et #Trichiuris trichiura$ sont rares et ne concernent qu'un peu moins de 2% des sujets examinés. Ces résultats démontrent l'absence, pour l'instant tout au moins, de foyers de transmission des bilharzioses dans les villages du périmètre de Diomandou. Le risque d'apparition de ces maladies est cependant important et dépend à la fois de l'évolution des infrastructures et de l'éventuelle apparition d'hôtes intermédiaires encore absent du réseau hydrographique de ce périmètre mis en place récemment. (Résumé d'auteur

    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

    Analisis Biaya Rumah Pracetak Berdasarkan Software Microsoft Project Di Perumahan Bulan Terang Utama Malang

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    Kebutuhan akan rumah murah berkualitas membuat PT. Bulan Terang Utama selaku developer rumah subsidi di Malang mengembangkan teknologi rumah pracetak sebagai rumah subsidi. Oleh karena itu diperlukan penelitian untuk membandingkan metode SNI serta MS. Project. Metode pembangunan struktur rumah pracetak adalah dengan pengecoran dinding beton bertulang dan kolomnya memakai besi siku yang dicor. Sehingga belum ada ketentuan dari SNI yang mengatur tentang pekerjaan rumah pracetak . Sehingga untuk menghitung biaya rumah pracetak digunakan software yaitu microsoft project. Penelitian mengenai analisis perhitungan biaya rumah pracetak berdasarkan perhitungan biaya dari developer dan berdasarkan software MS. Project. Objek penelitian ini adalah proyek pembangunan rumah pracetak di Perumahan Bulan Terang Utama Malang. Perhitungan dengan metode MS. Project menggunakan data berdasarkan perhitungan biaya langsung rumah pracetak dan penjadwalan/ timeline yang didapat dari developer. Dari hasil penelitian, metode analisis biaya yang digunakan adalah metode analisis biaya proyek dengan cara menghitung biaya langsung proyek. Metode analisis biaya proyek dengan cara menghitung biaya langsung proyek adalah metode yang menghitung harga bahan dan upah tenaga kerja secara keseluruhan sesuai keadaan proyek. Pada perencanaan proyek pembangunan rumah pracetak dibutuhkan total biaya pembangunan yang mendekati dengan riil biaya pelaksanaan. Sehingga metode analisis biaya proyek menghitung biaya langsung proyek ini dianggap adalah analisis biaya yang tepat. Metode MS Project 2007 adalah alternatif metode yang dapat digunakan untuk menganalisis harga untuk proyek tersebut. Metode ini digunakan karena sesuai dengan keadaan proyek yang memiliki data timeline/penjadwalan. Nilai total estimasi biaya rumah pracetak dengan menggunakan software microsoft project 2007 adalah Rp. 79.129.430,-. Total estimasi biaya dengan menggunakan software microsoft project 2007 selisih Rp.120,- dengan analisis biaya langsung proyek. Selisih ini terjadi diakibatkan karena pada MS. Project 2007 input data yang digunakan tidak bisa melebihi dua angka desimal di belakang koma

    Plasmodium falciparum malaria co-infection with tick-borne relapsing fever in Dakar

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    Abstract Background West African tick-borne relapsing fever (TBRF) due to Borrelia crocidurae and malaria are co-endemics in Senegal. Although expected to be high, co-infections are rarely reported. A case of falciparum malaria and B. crocidurae co-infection in a patient from Velingara (South of Senegal) is discussed. Case A 28\ua0year-old-male patient presented to Aristide Le Dantec Hospital for recurrent fever. He initially presented to a local post health of Pikine (sub-urban of Dakar) and was diagnosed for malaria on the basis of positive malaria rapid diagnostic test (RDT) specific to Plamodium falciparum . The patient was treated as uncomplicated falciparum malaria. Four days after admission the patient was referred to Le Dantec Hospital. He presented with fever (39\ua0\ub0C), soreness, headache and vomiting. The blood pressure was 120/80\ua0mmHg. The rest of the examination was normal. A thick film from peripheral blood was performed and addressed to the parasitology laboratory of the hospital. Thick film was stained with 10% Giemsa. Trophozoite of P. falciparum was identified at parasite density of 47 parasites per microlitre. The presence of Borrelia was also observed, concluding to malaria co-infection with borreliosis. Conclusions Signs of malaria can overlap with signs of borreliosis leading to the misdiagnosis of the latter. Thick and thin smear or QBC test or molecular method may be helpful to detect both Plamodium species and Borrelia . In addition, there is a real need to consider co-infections with other endemics pathogens when diagnosing malaria

    Joint distribution of the first and second eigenvalues at the soft edge of unitary ensembles

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    The density function for the joint distribution of the first and second eigenvalues at the soft edge of unitary ensembles is found in terms of a Painlev\'e II transcendent and its associated isomonodromic system. As a corollary, the density function for the spacing between these two eigenvalues is similarly characterized.The particular solution of Painlev\'e II that arises is a double shifted B\"acklund transformation of the Hasting-McLeod solution, which applies in the case of the distribution of the largest eigenvalue at the soft edge. Our deductions are made by employing the hard-to-soft edge transitions to existing results for the joint distribution of the first and second eigenvalue at the hard edge \cite{FW_2007}. In addition recursions under aa+1a \mapsto a+1 of quantities specifying the latter are obtained. A Fredholm determinant type characterisation is used to provide accurate numerics for the distribution of the spacing between the two largest eigenvalues.Comment: 26 pages, 1 Figure, 2 Table

    White Paper: Shifting the goal post - from high impact journals to high impact data

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    The purpose of this white paper is to provide an overview of the ongoing initiatives at center level to respond to changing public expectations and to the challenge of improving the conduct of science by making research data widely available. We also attempt to provide a framework for implementing open access for research data to maximize CGIAR’s impact on development. The remainder of this paper proceeds as follows; firstly a summary of the diversity of research data produced by the centers is given, followed by an overview of the existing infrastructure for data management for each Center. Secondly, some of the limitations and barriers faced by the centers in their process to mainstream research data publishing are addressed. The paper concludes with recommendations for how these limitations and barriers can be tackled

    Farmers' perceptions on mechanical weeders for rice production in sub-Saharan Africa

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    Competition from weeds is one of the major biophysical constraints to rice (Oryza spp.) production in sub-Saharan Africa. Smallholder rice farmers require efficient, affordable and labour-saving weed management technologies. Mechanical weeders have shown to fit this profile. Several mechanical weeder types exist but little is known about locally specific differences in performance and farmer preference between these types. Three to six different weeder types were evaluated at 10 different sites across seven countries – i.e., Benin, Burkina Faso, Côte d'Ivoire, Ghana, Nigeria, Rwanda and Togo. A total of 310 farmers (173 male, 137 female) tested the weeders, scored them for their preference, and compared them with their own weed management practices. In a follow-up study, 186 farmers from Benin and Nigeria received the ring hoe, which was the most preferred in these two countries, to use it during the entire crop growing season. Farmers were surveyed on their experiences. The probability of the ring hoe having the highest score among the tested weeders was 71%. The probability of farmers’ preference of the ring hoe over their usual practices – i.e., herbicide, traditional hoe and hand weeding – was 52, 95 and 91%, respectively. The preference of this weeder was not related to gender, years of experience with rice cultivation, rice field size, weed infestation level, water status or soil texture. In the follow-up study, 80% of farmers who used the ring hoe indicated that weeding time was reduced by at least 31%. Of the farmers testing the ring hoe in the follow-up study, 35% used it also for other crops such as vegetables, maize, sorghum, cassava and millet. These results suggest that the ring hoe offers a gender-neutral solution for reducing labour for weeding in rice as well as other crops and that it is compatible with a wide range of environments. The implications of our findings and challenges for out-scaling of mechanical weeders are discussed

    Renoval Charge Technic Applied To A Bifacial Solar Cell Under Constant Magnetic Field

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    An n+-p-p+ bifacial solar cell under constant magnetic field is placed in a fast-switch-interrupted circuit and submitted to a constant multi-spectral illumination. The transient decay occurs between two steady states throughoperating points depending on two variable resistors; this allows us to obtain a transient decay at any operating point of the I-V curve of the solar cell, from the short circuit to the open one. The influence of magnetic field on the transient photocurrent has been studied using Matlab Simulink simulations.These simulations lead to an equivalent circuit of the bifacial cell in transient state assuming that the photocurrent is the diffused
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