642 research outputs found

    Isolation and characterization ofmicrosatellitemarkers for Acacia senegal (L.)Willd., amultipurpose arid and semi-arid tree

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    International audienceAcacia senegal is a multipurpose African tree that improves the soil fertility of degraded areas. The species is exploited mainly for gum arabic, but it also supplies fuel wood and fod- der for animals. Despite its wide distribution in Africa, no microsatellite markers have yet been characterized for this species. In this study, we characterized 11 polymorphic microsatel- lite loci speciïŹcally designed for A. senegal and analysed 247 individuals from three popula- tions from Niger. On average, 10.9 alleles per locus were detected and expected heterozygosity ranged from 0.160 to 0.794, showing the ability of the markers to detect genetic diversity in this species

    Structure of the speciïŹc combining ability between two species of Eucalyptus. II. A clustering approach and a multiplicative model

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    International audienceThe Eucalyptus breeding program of URPPI (a partnership between CIRAD-Fore t, Centre National de la Recherche Forestie re du Congo, and Unite dÕAforestation Industrielle du Congo) consists of a re- ciprocal recurrent selection scheme developed in the Congo between the two species Eucalyptus urophylla and Eucalyptus grandis. Two approaches are proposed in order to model and predict the speciÞc combining ability (SCA) between these species. The clustering ap- proach uses a simultaneous clustering procedure of the two species based on SCA and reveals heterotic groups coherent with the geographical origins of E. urophylla genotypes. The second approach uses a multiplicative model to partition the SCA into three multiplicative terms explaining 95% of the interactio

    Structure of the speciïŹc combining ability between two species of Eucalyptus. I. RAPD data

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    International audienceWithin the context of the reciprocal recurrent selection scheme developed in 1989 by CIRAD-Fore t on Eucalyptus, RAPD essays were performed to assess the genetic diversity in the two species E. urophylla and E. grandis. The molecular markers were split into two parts: the speciÞc markers (present with di€erent fre- quencies in the two species) and the common markers (present with similar frequencies in the two species). The study analyses the structure of genetic diversity within and between the two species of Eucalyptus. Dif- ferent genetic distances are worked out for use in pre- diction equations of the individual tree trunk volume of hybrids at 38 months. Each distance is expressed as the sum of the general genetic distance and the speciÞc genetic distance. The general genetic distance based on the double presence plus the double absence of bands seems to be an interesting co-variate to use in a factor regression model. Through this model the distance calculated between species explains the general com- bining ability (GCA) and the speciÞc combining ability (SCA) of the phenotypic character with a global coeŠc- ient of determination of 81.6

    Gene flow estimation with microsatellites in a Malagasy seed orchard of Eucalyptus grandis

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    International audienceEucalyptus grandis has a mixed-mating repro- ductive system. Malagasy Eucalyptus seed orchards were established 15 years ago with two aims both based on panmixia: open-pollinated seed production and genetic improvement. The panmixia hypothesis has never been confirmed in the seed orchard. From a seedling seed- orchard stand comprising 349 trees and using data obtained with six selected microsatellite markers, pater- nity analysis was performed for 724 offspring collected on 30 adult trees. Paternity assignment, based on exclu- sion procedures and likelihood-ratio method, was achieved with high accuracy; the exclusion probability value was 0.997. The outcrossing rate was very high (96.7%). More than 50% of potential male trees (199 out of 349) in the seed orchard contributed to pollination for 440 offspring of 30 progenies (8.6% of the basic population). The pollination rate from outside the seed orchard was high (39.2%), but might be due to the small size of this seed orchard. This study showed that "panmixia-like pollination" can be assume

    Laboratory study of the impact of repetitive electrical and mechanical stimulation on brown shrimp Crangon crangon

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    Pulse trawling is currently the best available alternative to beam trawling in the brown shrimp Crangon crangon and Sole Solea solea (also known as Solea vulgaris) fisheries. To evaluate the effect of repetitive exposure to electrical fields, brown shrimp were exposed to the commercial electrodes and pulse settings used to catch brown shrimp (shrimp startle pulse) or Sole (Sole cramp pulse) 20 times in 4 d and monitored for up to 14 d after the first exposure. Survival, egg loss, molting, and the degree of intranuclear bacilliform virus (IBV) infection were evaluated and compared with those in stressed but not electrically exposed (procedural control) and nonstressed, nonexposed (control) brown shrimp as well as brown shrimp exposed to mechanical stimuli. The lowest survival at 14 d (57.3%) occurred in the Sole cramp pulse treatment, and this was significantly lower than in the group with the highest survival, the procedural control (70.3%). No effect of electrical stimulation on the severity of IBV infection was found. The lowest percentage of molts occurred in the repetitive mechanical stimulation treatment (14.0%), and this was significantly lower than in the group with the highest percentage of molts, the procedural control (21.7%). Additionally, the mechanically stimulated brown shrimp that died during the experiment had a significantly larger size than the surviving individuals. Finally, no effect of the shrimp startle pulse was found. Therefore, it can be concluded that repetitive exposure to a cramp stimulus and mechanical stimulation may have negative effects on the growth and/or survival of brown shrimp. However, there is no evidence that electrical stimulation during electrotrawls would have a larger negative impact on brown shrimp stocks than mechanical stimulation during conventional beam trawling

    The relevance of arterial blood pressure in the management of glaucoma progression: a systematic review

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    Background Glaucoma is one of the leading causes of global blindness and is expected to co-occur more frequently with vascular morbidities in the upcoming years, as both are aging-related diseases. Yet, the pathogenesis of glaucoma is not entirely elucidated and the interplay between intraocular pressure, arterial blood pressure and ocular perfusion pressure is poorly understood. Objective This systematic review aims to provide clinicians with the latest literature regarding the management of arterial blood pressure in glaucoma patients. Methods A systematic search was performed in Medline, Embase, Web of Science and Cochrane Library. Articles written in English assessing the influence of arterial blood pressure and systemic antihypertensive treatment of glaucoma and its management were eligible for inclusion. Additional studies were identified by revising references included in selected articles. Results 80 articles were included in this systemic review. A bimodal relation between blood pressure and glaucoma progression was found. Both high and low blood pressure increase the risk of glaucoma. Glaucoma progression was, possibly via ocular perfusion pressure variation, strongly associated with nocturnal dipping and high variability in the blood pressure over 24-hours. Conclusions We concluded that systemic blood pressure level associates with glaucomatous damage and provided recommendations for the management and study of arterial blood pressure in glaucoma. Prospective clinical trials are needed to further support these recommendations

    Probabilistic abstract interpretation: From trace semantics to DTMC’s and linear regression

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    In order to perform probabilistic program analysis we need to consider probabilistic languages or languages with a probabilistic semantics, as well as a corresponding framework for the analysis which is able to accommodate probabilistic properties and properties of probabilistic computations. To this purpose we investigate the relationship between three different types of probabilistic semantics for a core imperative language, namely Kozen’s Fixpoint Semantics, our Linear Operator Semantics and probabilistic versions of Maximal Trace Semantics. We also discuss the relationship between Probabilistic Abstract Interpretation (PAI) and statistical or linear regression analysis. While classical Abstract Interpretation, based on Galois connection, allows only for worst-case analyses, the use of the Moore-Penrose pseudo inverse in PAI opens the possibility of exploiting statistical and noisy observations in order to analyse and identify various system properties

    Comprehensive genetic dissection of wood properties in a widely-grown tropical tree: Eucalyptus

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    Background: Eucalyptus is an important genus in industrial plantations throughout the world and is grown for use as timber, pulp, paper and charcoal. Several breeding programmes have been launched worldwide to concomitantly improve growth performance and wood properties (WPs). In this study, an interspecific cross between Eucalyptus urophylla and E. grandis was used to identify major genomic regions (Quantitative Trait Loci, QTL) controlling the variability of WPs. Results: Linkage maps were generated for both parent species. A total of 117 QTLs were detected for a series of wood and end-use related traits, including chemical, technological, physical, mechanical and anatomical properties. The QTLs were mainly clustered into five linkage groups. In terms of distribution of QTL effects, our result agrees with the typical L-shape reported in most QTL studies, i.e. most WP QTLs had limited effects and only a few (13) had major effects (phenotypic variance explained > 15%). The co-locations of QTLs for different WPs as well as QTLs and candidate genes are discussed in terms of phenotypic correlations between traits, and of the function of the candidate genes. The major wood property QTL harbours a gene encoding a Cinnamoyl CoA reductase (CCR), a structural enzyme of the monolignol-specific biosynthesis pathway. Conclusions: Given the number of traits analysed, this study provides a comprehensive understanding of the genetic architecture of wood properties in this Eucalyptus full-sib pedigree. At the dawn of Eucalyptus genome sequence, it will provide a framework to identify the nature of genes underlying these important quantitative traits. (Résumé d'auteur
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