679 research outputs found

    Analysis of incompatibility barriers during cross-pollinations among Phaseolus L. and other leguminous plants

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    Plant breeding is intended to seek for ways of realizing a genetic structure adapted to criteria and population needs. In this context, cross-pollinations are for great interest. They offer the means of creating a wide genotypic variability. However, a limited number of species are able to undergo hybridization studies. In Phaseolus L., improvement can be envisioned by either exploiting the primary genetic pool of the species, or the genetic variability of other species. In fact, there are wild or wild-like species more resistant to stresses or diseases than the cultivated ones. The methods of embryo rescues facilitate the interspecific crosses and contribute to exploiting the available genetic diversity within plant germplasm. Difficulties related to obtaining hybrids in grain legumes, and Phaseolus L. in particular, are reported in this research. It is possible to avoid the incompatibility barriers based on their appearance time. When they are pre-zygotic, the use of growth regulators during pollination is recommended. The in vitro explants culture is the most usual method to overcome the post-zygotic barriers. The mechanisms leading to abortion of hybrid embryos, as well as adequate methods to overcome the interspecific incompatibilities should be subjected to further studies.Keywords: Abortion, hybridization, interspecific barriers, Phaseolus L., plant embryos

    Effect of floral debris removal from fruit clusters on botrytis bunch rot of Chardonnay grapes

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    The relationship between senescent floral debris retained in fruit clusters and the incidence and severity of botrytis bunch rot was examined in Chardonnay grapevines over three seasons. Floral debris was removed from clusters at either early or late fruit set using compressed air or a back-pack leaf blower. Additional treatments were included to determine if a commercial sticker spray adjuvant (Nu-Film 17) increased debris retention in clusters. Physical removal of floral debris generally reduced botrytis bunch rot; however, reductions in botrytis bunch rot were only significant in some vineyards. The sticker spray adjuvant had no effect on retention of debris or on botrytis bunch rot. The incidence and severity of botrytis bunch rot were not affected by timing of debris removal, but late removal by compressed air, when berries were as much as 8 mm in diameter, did cause berry bruising. The data demonstrate that senescent floral debris and aborted berries can contribute to increased botrytis bunch rot, and that practical measures to reduce debris retention may aid disease control

    The subelliptic heat kernel on SU(2): Representations, Asymptotics and Gradient bounds

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    The Lie group SU(2) endowed with its canonical subriemannian structure appears as a three-dimensional model of a positively curved subelliptic space. The goal of this work is to study the subelliptic heat kernel on it and some related functional inequalities.Comment: Update: Added section + Correction of typo

    Malliavin calculus for fractional heat equation

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    In this article, we give some existence and smoothness results for the law of the solution to a stochastic heat equation driven by a finite dimensional fractional Brownian motion with Hurst parameter H>1/2H>1/2. Our results rely on recent tools of Young integration for convolutional integrals combined with stochastic analysis methods for the study of laws of random variables defined on a Wiener space.Comment: Dedicated to David Nualart on occasion of his 60th birthda

    System of Complex Brownian Motions Associated with the O'Connell Process

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    The O'Connell process is a softened version (a geometric lifting with a parameter a>0a>0) of the noncolliding Brownian motion such that neighboring particles can change the order of positions in one dimension within the characteristic length aa. This process is not determinantal. Under a special entrance law, however, Borodin and Corwin gave a Fredholm determinant expression for the expectation of an observable, which is a softening of an indicator of a particle position. We rewrite their integral kernel to a form similar to the correlation kernels of determinantal processes and show, if the number of particles is NN, the rank of the matrix of the Fredholm determinant is NN. Then we give a representation for the quantity by using an NN-particle system of complex Brownian motions (CBMs). The complex function, which gives the determinantal expression to the weight of CBM paths, is not entire, but in the combinatorial limit a0a \to 0 it becomes an entire function providing conformal martingales and the CBM representation for the noncolliding Brownian motion is recovered.Comment: v3: AMS_LaTeX, 25 pages, no figure, minor corrections made for publication in J. Stat. Phy

    Análisis de linajes maternos y paternos de bovinos criollo del Centro de Ecología Aaplicada Simón I. Patiño - Bolivia

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    Se determinaron los linajes maternos y paternos de 33 bovinos Criollo (27 hembras y 6 machos) del Centro de Ecología Aplicada Simón I. Patiño (Ceasip) mediante marcadores genéticos del ADN genómico, mitocondrial y del cromosoma Y. El ADN genómico se extrajo utilizando el kit Wizard ® Genomic Purification. Los linajes maternos se determinaron mediante secuenciación del ADN mitocondrial (región control D-loop) y los linajes paternos se determinaron analizando siete marcadores genéticos del cromosoma Y, dos SNP (Polimorfismo de Nucleótido Simple) y cinco microsatélites (Secuencias Repetidas en Tándem). La diversidad genética se estimó tipificando 18 microsatélites. Se analizaron los datos con MStools, GenePop y Arlequin. La secuenciación de D-loop mitocondrial permitió detectar seis linajes maternos, que incluían cuatro haplotipos mitocondriales de origen europeo y dos africanos. A través del análisis de los marcadores del cromosoma Y se determinaron tres linajes paternos, dos taurinos y uno cebuino. En el hato del Ceasip, la diversidad alélica (na) fue de 6.11, mientras que la heterocigosidad esperada (He) fue de 0.70 y la observada (Ho) fue de 0.68. Los valores de diversidad genética observada en los bovinos del Ceasip son similares a los estimados para la mayoría de los biotipos del Criollo boliviano (na Yacumeño= 6.82; na Saavedreño= 5.95), siendo los valores promedios para el ganado Criollo boliviano analizados anteriormente de na= 6.39, He= 0.72 y Ho= 0.65. Los análisis de Componentes Principales y de distancia genética mostraron que sería factible intercambiar material genético entre las poblaciones Criollo bolivianas sin pérdida significativa de su diversidad genética.Fil: Pereira, J. A. C.. Universidad Autónoma Gabriel René Moreno; BoliviaFil: Giovambattista, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Peña, S.. Centro de Ecología Aplicada Simón I. Patiño; BoliviaFil: Liron, Juan Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Genética Veterinaria ; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Loza, A. J.. Universidad Autónoma Gabriel René Moreno; BoliviaFil: Posik, Diego Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Genética Veterinaria ; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Baudoin, M.. Centro de Ecología Aplicada Simón I. Patiño; BoliviaFil: Bomblat, C.. Centro de Ecología Aplicada Simón I. Patiño; Bolivi

    Explicit formulae in probability and in statistical physics

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    We consider two aspects of Marc Yor's work that have had an impact in statistical physics: firstly, his results on the windings of planar Brownian motion and their implications for the study of polymers; secondly, his theory of exponential functionals of Levy processes and its connections with disordered systems. Particular emphasis is placed on techniques leading to explicit calculations.Comment: 14 pages, 2 figures. To appear in Seminaire de Probabilites, Special Issue Marc Yo

    Reliability testing of tendon disease using two different scanning methods in patients with rheumatoid arthritis

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    Objective. To assess the intra- and interobserver reliability of musculoskeletal ultrasonography (US) in detecting inflammatory and destructive tendon abnormalities in patients with RA using two different scanning methods.Methods. Thirteen observers examined nine patients with RA and one healthy individual in two rounds independently and blindly of each other. Each round consisted of two consecutive examinations, an anatomy-based examination and a free examination according to personal preferences. The following tendons were evaluated: wrist extensor compartments 2, 4 and 6, finger flexor tendons 3 and 4 at MCP level, tibialis posterior tendon and both peronei tendons. Overall, positive and negative agreements and κ-values for greyscale (GS) tenosynovitis, peritendinous power Doppler (PPD) signal, intratendinous power Doppler (IPD) signal and GS tendon damage were calculated.Results. Intraobserver κ-value ranges were 0.53-0.55 (P < 0.0005) for GS tenosynovitis, 0.61-0.64 (P < 0.0005) for PPD signal, 0.65-0.66 (P < 0.0005) for IPD signal and 0.44-0.53 (P < 0.0005) for GS tendon damage. For interobserver reliability, substantial overall agreement ranged from 80 to 89% for GS tenosynovitis, 97 to 100% for PPD signal, 97 to 100% for IPD signal and 97 to 100% for GS tendon damage. Results were independent of scanning technique.Conclusion. Intraobserver reliability for tenosynovitis and tendon damage varied from moderate for GS to good for PD. Overall interobserver reliability for tenosynovitis and tendon damage was excellent both for GS and PD. This qualitative scoring system may serve as the first step to a semi-quantitative score for tendon pathology. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved

    Managing Mediterranean nurse plants-mediated effects on soil microbial functions to improve rock phosphate solubilization processes and early growth of Cupressus atlantica G

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    a b s t r a c t The main objective was to evaluate the impact of nurse plant species commonly found in Mediterranean areas (Lavandula dentata and Thymus satureoides) on microbial soil functions, on the native inoculum potential of AM fungi involved in the rock phosphate weathering and to measure the potential benefits to the growth of Atlas Cypress (Cupressus atlantica G.), an endemic Cupressacea of Morocco. Soils collected from an old C. atlantica forest and pre-cultivated with each of the target plant species (L. dentata and T. satureoides). After 5 months of cultivation, they were uprooted and the treated substrate was amended or not with Khouribga Rock Phosphate (KRP). Then pots were filled with the soil mixtures and planted with one pre-germinated seed of C. atlantica. The results show that pre-cultivation step with native mycotrophic plant species improves the mycorrhizal soil infectivity, modifies soil microbial functionalities and increases the impact of rock phosphate amendment on the C. atlantica growth. This low cost cultivation practice by improving forest plant development and cultural soil quality constitutes a promising ecological engineering tool to improve the performances of ecosystem restoration
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