661 research outputs found

    Etude Comparative de l’effet de Souches de Champignons Mycorhiziens Arbusculaires sur la Croissance et la Nutrition MinĂ©rale du SĂ©same CultivĂ© au SĂ©nĂ©gal

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    La croissance et la nutrition minĂ©rale de huit variĂ©tĂ©s locales de SĂ©same (Sesamum indicum L.) ont Ă©tĂ© Ă©valuĂ©es en rĂ©ponse Ă  l’inoculation mycorhizienne arbusculaire. Les essais conduits en serre pendant trois mois, ont montrĂ© un meilleur dĂ©veloppement et une meilleure nutrition minĂ©rale chez les plants inoculĂ©s comparĂ© aux tĂ©moins non inoculĂ©s. Les variĂ©tĂ©s testĂ©es se sont rĂ©vĂ©lĂ©es trĂšs dĂ©pendantes de la mycorhization arbusculaire. Le degrĂ© de dĂ©pendance est gĂ©nĂ©ralement supĂ©rieur Ă  55 % et est fortement corrĂ©lĂ© Ă  l’isolat fongique et Ă  la variĂ©tĂ© testĂ©e. Il ressort de cette Ă©tude que les biofertilisants Ă  base de champignons mycorhiziens procurent des bĂ©nĂ©fices importants Ă  la plante, et peuvent ĂȘtre utilisĂ©s pour amĂ©liorer la croissance et le rendement du sĂ©same.Mots ClĂ©s: Biofertilisation, Mycorhizienne, Sesamum indicumThe growth and mineral nutrition of eight local varieties of Sesame (Sesamum indicum L.) were evaluated in response to arbuscular mycorrhiza inoculation in a greenhouse. There was greater plant growth and better mineral nutrition in inoculated pots compared to non-inoculated controls. The varieties tested showed high dependence on arbuscular mycorrhiza. The degree of dependence was generally greater than 55% and was highly correlated with the fungal isolates and variety tested. It is evident that mycorrhizae fungi-based biofertilisers provide significant benefits to the plant and can be used to improve growth and yield in sesame.Keywords: Biofertilisation, Mycorrhiza, Sesamum indicu

    Electron-phonon coupling and its evidence in the photoemission spectra of lead

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    We present a detailed study on the influence of strong electron-phonon coupling to the photoemission spectra of lead. Representing the strong-coupling regime of superconductivity, the spectra of lead show characteristic features that demonstrate the correspondence of physical properties in the normal and the superconducting state, as predicted by the Eliashberg theory. These features appear on an energy scale of a few meV and are accessible for photoemission only by using modern spectrometers with high resolution in energy and angle.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

    Effect of an Outpatient Education Program on Knowledge and Healthy Behavior Change of Patients Who Have Undergone Percutaneous Transluminal Coronary Angioplasty

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    72 leavesAn outpatient education program for patients who have undergone percutaneous transluminal coronary angioplasty was evaluated to determine if there was an increase in knowledge of a change in healthy behaviors as a result of the program. The sample consisted of 48 patients; 24 who experienced an outpatient education program and 24 who did not. Three instruments developed by the investigator were used. Both groups completed a demographics form, a knowledge assessment form and a lifestyle assessment form before the program began. The knowledge assessment form and lifestyle assessment form were completed again six weeks after the program. Both groups showed a statistically significant increase in knowledge (p<.05). The experimental group showed a statistically significant increase in exercise behavior (p<.05). Because both groups showed a statistically significant increase in knowledge, this change could not be attributed to the program. Only the experimental group showed an increase in healthy behaviors, however. Therefore, the education program was effective in influencing patients to become more responsible for their treatment and care

    The high-pressure alpha/beta phase transition in lead sulphide (PbS): X-ray powder diffraction and quantum mechanical calculations

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    The high-pressure behaviour of PbS was investigated by angular dispersive X-ray powder diffraction up to pressures of 6.8 GPa. Experiments were accompanied by first principles calculations at the density functional theory level. By combining both methods reliable data for the elastic properties of rock-salt type alpha- and high-pressure beta-PbS could be obtained. beta-PbS could be determined to crystallise in the CrB-type (B33), with space group Cmcm. The reversible ferro-elastic alpha/beta transition is of first order. It is accompanied by a large volume discontinuity of about 5% and a coexistence region of the two phases. A gliding mechanism of {001} bilayers along one of the cubic -directions governs the phase transition which can be described in terms of group/subgroup relationships via a common subgroup, despite its reconstructive character. The quadrupling of the primitive unit cell indicates a wave vector (0,0,pi/a) on the Delta-line of the Brillouin zone.Comment: 7 pages, 5 figures, 3 tables submitted to EP

    Signature of quantum criticality in photoemission spectroscopy at elevated temperature

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    A quantum phase transition (QPT) in a heavy-fermion (HF) compound may destroy the Fermi liquid groundstate. However, the conditions for this breakdown have remained obscure. We report the first direct investigation of heavy quasiparticle formation and breakdown in the canonical system CeCu6−x_{6-x}Aux_x by ultraviolet photoemission spectroscopy at elevated temperatures without the complications of lattice coherence. Surprisingly, the single-ion Kondo energy scale TKT_K exhibits an abrupt step near the quantum critical Au concentration of xc=0.1x_c=0.1. We show theoretically that this step is expected from a highly non-linear renormalization of the local spin coupling at each Ce site, induced by spin fluctuations on neighboring sites. It provides a general high-temperature indicator for HF quasiparticle breakdown at a QPT.Comment: Published version, PRL, minor changes in wordin

    Experimental study of slow sand filtration for the treatment of various wastewaters in tropical environment

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    Wastewater treatment by slow sand filtration is a biological process which consists in filtering wastewater through a porous media. The objective of this study was to evaluate the performances of this biotechnology under tropical climate. Three sand filters were monitored at ONAS (CambérÚne wastewater treatment plant in Dakar, Senegal). The filters were built with local materials, and were constituted with a feeding tank of approximately 180 litters, a column (two meters high and 30-25 cm diameter). The filters were filled with sand (75 cm), gravel (25 cm) and wastewater (90 cm). The results showed that with sand of d10 equal to 0.58 mm and flow rate of 0.05 m/h, the filtration cycle was relatively long for the first run with pretreated wastewater. At the level of the primary settling tank, with flow a rate of 0.08 m/h, the removal rates were about 12.75%, 16.31%, 12.92%, 5.45%, 7.09% and 10.50% for TSS, COD, BOD5, nitrogen phosphorus and faecal coliforms respectively. At the level of the clarifier, with a filtration of 0.15 m/h, the removals were 1.4% for TSS, 1.84% for COD, 1.09% for BOD5 11.38% for nitrogen, 5.18% for phosphorus and 1.74% of faecal coliforms.Keywords: Flow rate; filtration cycle, removal; sand filtration; tropical climate, wastewater

    Comparing variant calling algorithms for target-exon sequencing in a large sample

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    Abstract Background Sequencing studies of exonic regions aim to identify rare variants contributing to complex traits. With high coverage and large sample size, these studies tend to apply simple variant calling algorithms. However, coverage is often heterogeneous; sites with insufficient coverage may benefit from sophisticated calling algorithms used in low-coverage sequencing studies. We evaluate the potential benefits of different calling strategies by performing a comparative analysis of variant calling methods on exonic data from 202 genes sequenced at 24x in 7,842 individuals. We call variants using individual-based, population-based and linkage disequilibrium (LD)-aware methods with stringent quality control. We measure genotype accuracy by the concordance with on-target GWAS genotypes and between 80 pairs of sequencing replicates. We validate selected singleton variants using capillary sequencing. Results Using these calling methods, we detected over 27,500 variants at the targeted exons; >57% were singletons. The singletons identified by individual-based analyses were of the highest quality. However, individual-based analyses generated more missing genotypes (4.72%) than population-based (0.47%) and LD-aware (0.17%) analyses. Moreover, individual-based genotypes were the least concordant with array-based genotypes and replicates. Population-based genotypes were less concordant than genotypes from LD-aware analyses with extended haplotypes. We reanalyzed the same dataset with a second set of callers and showed again that the individual-based caller identified more high-quality singletons than the population-based caller. We also replicated this result in a second dataset of 57 genes sequenced at 127.5x in 3,124 individuals. Conclusions We recommend population-based analyses for high quality variant calls with few missing genotypes. With extended haplotypes, LD-aware methods generate the most accurate and complete genotypes. In addition, individual-based analyses should complement the above methods to obtain the most singleton variants.http://deepblue.lib.umich.edu/bitstream/2027.42/110906/1/12859_2015_Article_489.pd

    Comparing variant calling algorithms for target-exon sequencing in a large sample

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    Abstract Background Sequencing studies of exonic regions aim to identify rare variants contributing to complex traits. With high coverage and large sample size, these studies tend to apply simple variant calling algorithms. However, coverage is often heterogeneous; sites with insufficient coverage may benefit from sophisticated calling algorithms used in low-coverage sequencing studies. We evaluate the potential benefits of different calling strategies by performing a comparative analysis of variant calling methods on exonic data from 202 genes sequenced at 24x in 7,842 individuals. We call variants using individual-based, population-based and linkage disequilibrium (LD)-aware methods with stringent quality control. We measure genotype accuracy by the concordance with on-target GWAS genotypes and between 80 pairs of sequencing replicates. We validate selected singleton variants using capillary sequencing. Results Using these calling methods, we detected over 27,500 variants at the targeted exons; >57% were singletons. The singletons identified by individual-based analyses were of the highest quality. However, individual-based analyses generated more missing genotypes (4.72%) than population-based (0.47%) and LD-aware (0.17%) analyses. Moreover, individual-based genotypes were the least concordant with array-based genotypes and replicates. Population-based genotypes were less concordant than genotypes from LD-aware analyses with extended haplotypes. We reanalyzed the same dataset with a second set of callers and showed again that the individual-based caller identified more high-quality singletons than the population-based caller. We also replicated this result in a second dataset of 57 genes sequenced at 127.5x in 3,124 individuals. Conclusions We recommend population-based analyses for high quality variant calls with few missing genotypes. With extended haplotypes, LD-aware methods generate the most accurate and complete genotypes. In addition, individual-based analyses should complement the above methods to obtain the most singleton variants.http://deepblue.lib.umich.edu/bitstream/2027.42/134735/1/12859_2015_Article_489.pd

    Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2

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    We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly-correlated Ce system CeCu2_2Si2_2. Exploiting the thermal broadening of the Fermi edge we analyze position, spectral weight, and temperature dependence of the low-energy 4f spectral features, whose major weight lies above the Fermi level EFE_F. We also present theoretical predictions based on the single-impurity Anderson model using an extended non-crossing approximation (NCA), including all spin-orbit and crystal field splittings of the 4f states. The excellent agreement between theory and experiment provides strong evidence that the spectral properties of CeCu2_2Si2_2 can be described by single-impurity Kondo physics down to T≈5T \approx 5 K.Comment: 4 pages, 3 figure
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