Application of Random Matrix Theory to Multivariate Statistics

This is an expository account of the edge eigenvalue distributions in random matrix theory and their application in multivariate statistics. The emphasis is on the Painlev\'e representations of these distributions

Improvement of mixed farming systems in Sudano-Sahelian Africa. Role of the species Stylosanthes hamata (L.) Taub. A review

Introduction. In Sudano-Sahelian Africa, the traditional farming systems are no longer able to meet the food needs of the population. In order to sustainably improve the food security of small family farms, agro-ecological practices are increasingly being promoted by research and development organizations. Literature. Several studies have shown that agricultural productivity can be sustainably improved through a better integration of agriculture and livestock activities. One approach currently being considered is the integration into farming systems of Stylosanthes hamata (L.) Taub: a herbaceous annual to short-lived perennial. This plant has the proven potential to enhance the performance of cropping systems in many ways. It also allows for the critical production of a high quality fodder for animal feed, from the second year after planting onwards. However, phytosanitary, technical, environmental and / or socio-economic constraints would need to be lifted to allow a better integration of the crop into farming systems. Conclusions. Integration of S. hamata into the farming systems of the Sudano-Sahelian regions presents potential benefits that merit further investigation, in order to identify the appropriate modalities for this integration. © 2015, FAC UNIV SCIENCES AGRONOMIQUES GEMBLOUX. All rights reserved

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

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

Perceived sources of stress and anxiety among Senegalese dental students

Background: Dental studies are stressful and anxiety-provoking. The aim of this study was to assess the stress and anxiety levels of dental students at Cheikh Anta Diop university in Dakar, Senegal. Methods: A descriptive cross-sectional study was conducted among 133 students. A general stress self-questionnaire (Perceived stress scale 14), another specific to dentistry studies and a final Spielberger anxiety questionnaire were distributed manually or electronically to students regularly enrolled in master’s 1 and 2 at the institute of odontology and stomatology of Cheikh Anta Diop university in Dakar. Results: A total of 121 students responded, giving a response rate of 90.97%. The average stress level was 20.8±1.08. Of these, 14 students (11.6%) had mild stress, 75.2% had moderate stress and 13.2% had high stress. The most commonly reported stress factors specific to dentistry studies were examinations and ongoing tests (67.7%), the pre-clinical transition to the clinic (70.3%), patient delays or missed appointments (83.5%), fear of making mistakes (67%, i.e., perforation, medical contraindications, etc.), the availability of equipment (70.3%), and conservative odontology and endodontics procedures (71.6%). Concerning anxiety, 113 students (93.4%) had a moderate level of anxiety and 2 students (1.6%) had a high level of anxiety. Conclusions: This study showed that stress and anxiety are frequently found among dental students. Intervention strategies based on raising awareness and promoting psychological well-being in the educational context should be adopted for these students

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

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

Quantum Thetas on Noncommutative T^4 from Embeddings into Lattice

In this paper we investigate the theta vector and quantum theta function over noncommutative T^4 from the embedding of R x Z^2. Manin has constructed the quantum theta functions from the lattice embedding into vector space (x finite group). We extend Manin's construction of the quantum theta function to the embedding of vector space x lattice case. We find that the holomorphic theta vector exists only over the vector space part of the embedding, and over the lattice part we can only impose the condition for Schwartz function. The quantum theta function built on this partial theta vector satisfies the requirement of the quantum theta function. However, two subsequent quantum translations from the embedding into the lattice part are non-additive, contrary to the additivity of those from the vector space part.Comment: 20 pages, LaTeX, version to appear in J. Phys.

Déterminants de la demande de soins en milieu péri-urbain dans un contexte de subvention à Pikine, Sénégal

Depuis les années 2000, le Sénégal a adopté des politiques nationales visant la suppression progressive du paiement direct au point de services pour rendre les soins de santé plus accessibles. La mise en place de ces politiques de subvention et de gratuité dans un espace dense hétérogène voire hétéroclite, présente une situation particulière. Pour comprendre ces interactions et étudier le comportement des ménages en matière de demande de soins, 5520 individus ont étés enquêtés à quatre reprises sur la période 2010-2011 dans la banlieue de Dakar (Pikine), un probit multinomial est estimé pour étudier la demande de soins de la population face à un épisode de maladie. Les résultats montrent que l'effet négatif du prix est en moyenne assez faible, mais qu'il varie en fonction du niveau de revenu et de la sévérité de la maladie. La qualité perçue des soins a un effet positif sur le recours aux services de santé privés pour lesquels on observe une compensation de l'effet négatif du prix par la qualité. L'effet de l'âge n'est pas linéaire et les enfants, plus touchés par la maladie, bénéficient de peu d'exemption ou du moins d'exemption partielle contrairement aux personnes âgées qui bénéficient d'exemption totale (plan SESAME)

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

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

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

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