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Search Results: 1 - 10 of 1054 matches for " Freddy; Perret "
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Aplicación de técnicas bayesianas en el análisis genético de árboles forestales
Mora,Freddy; Perret,Sandra;
Bosque (Valdivia) , 2007, DOI: 10.4067/S0717-92002007000300003
Abstract: this study was undertaken to investigate bayesian methods to scientific inference in forest tree breeding. the independence chain (ic) and gibbs sampling (gs) algorithms were applied on data sets from a field trial of eucalyptus cladocalyx aiming to predict random family and additive genetic effects, respectively. the trial was carried out in the coastal area of coquimbo region, northern chile. diameter and height growth rate (tcd and tca) were the data sets collected in a period of 30 months. bayesian procedures were compared with the ranking obtained by best linear unbiased prediction (blup). blup and ic had similar family ranking, although the family selection based on credible intervals of the genoty-pic effects (bayesian framework) was clearly more intensive. spearman rank correlation coefficients were high and significant (ps= 0.99) between blup and gs. the estimates of heritability were moderate: h2= 0.42 (tca) and h2= 0.43 (tcd). the traits had a significant correlation (ts= 0.7). the estimated genetic gains, in relation to the experimental average, ranged from 17% to 28%. the greatest genetic gain and genetic diversity of the original diversity of the experimental populations may be achieved and maintained if the trees are selected for tcd. it was conclude hat the bayesian inference may be a useful tool in the genetic evaluation of forest trees, since it incorporates the variability of the genetic parameters by using posterior distributions
Aplicación de técnicas bayesianas en el análisis genético de árboles forestales Applications of bayesian techniques in forest tree breeding
Freddy Mora,Sandra Perret
Bosque (Valdivia) , 2007,
Abstract: El objetivo de este estudio fue investigar los métodos bayesianos como una alternativa de inferencia científica aplicada a la evaluación genética forestal. Se usaron los algoritmos de Cadenas Independientes (IC) y de Gibbs (GS) en un conjunto de datos provenientes de un ensayo de Eucalyptus cladocalyx, para la predicción del efecto familiar e individual, respectivamente. El ensayo fue establecido en el sector costero de la Región de Coquimbo, norte de Chile. Se evaluó la tasa de crecimiento promedio de la altura (TCA) y el diámetro (TCD), medidas en un periodo de 30 meses. Los procedimientos se compararon con la mejor predicción linear inses-gada (BLUP). Se confirmó una significativa asociación entre el ranking familiar de BLUP e IC, aunque se evidenciaron mayores intensidades de selección al utilizar las regiones de credibilidad de los efectos genotípicos (enfoque bayesiano). Se obtuvieron altas y significativas correlaciones de Spearman (Ts= 0,9) entre BLUP y GS. Se obtuvieron moderadas heredabilidades individuales: h2=0,42 (TCA) y h2 = 0,43 (TCD). Las características se correlacionaron significativamente entre sí (Fs = 0,7). Las ganancias genéticas, en relación al promedio del ensayo, variaron de 17% a 28%. Al seleccionar para TCD, mayor ganancia y diversidad genética puede ser alcanzada y mantenida que la diversidad encontrada en este ensayo de progenie. Se concluyó que la inferencia bayesiana puede ser una herramienta metodológica útil en la evaluación genética forestal, ya que permitió incorporar la variación de los parámetros genéticos a través de las distribuciones a posteriori This study was undertaken to investigate bayesian methods to scientific inference in forest tree breeding. The Independence Chain (IC) and Gibbs sampling (GS) algorithms were applied on data sets from a field trial of Eucalyptus cladocalyx aiming to predict random family and additive genetic effects, respectively. The trial was carried out in the coastal area of Coquimbo Region, northern Chile. Diameter and height growth rate (TCD and TCA) were the data sets collected in a period of 30 months. Bayesian procedures were compared with the ranking obtained by Best Linear Unbiased Prediction (BLUP). BLUP and IC had similar family ranking, although the family selection based on credible intervals of the genoty-pic effects (bayesian framework) was clearly more intensive. Spearman rank correlation coefficients were high and significant (Ps= 0.99) between BLUP and GS. The estimates of heritability were moderate: h2= 0.42 (TCA) and h2= 0.43 (TCD). The traits had a significant corre
Genetic parameters of growth and survival in Acacia saligna shrubs
Mora,Freddy; Perret,Sandra; Scapim,Carlos Alberto; Arnhold,Emmanuel;
Ciencia e investigación agraria , 2010, DOI: 10.4067/S0718-16202010000200001
Abstract: acacia species have valuable agronomic characteristics, such as the tolerance to unfavorable environmental conditions. in this study, genetic parameters and selection response in acacia saligna shrubs were investigated in two arid environments of northern chile: cuz-cuz and el tangue. the quantitative traits were assessed in 5 year-old shrubs. a bayesian approach, implemented using gibbs sampling algorithm, was used in the data analysis. the tree survival was 87.3% and 81.8% in cuz-cuz and el tangue, respectively, confirming the potential of a. saligna in northern chile. the estimates of posterior mode of the heritability ranged from h2=0.13 (survival) to h2=0.25 (shrub crown diameter). estimated genetic gain (individual tree selection) ranged from 6 to 14% (selection intensity of 20%). bayesian credible intervals (p=95%) for genotype-environment correlations included zero, indicating a significant interaction for survival, crown diameter and height. shrub selection in multipurpose planting will depend on optimizing economical traits by selecting genotypes that perform well on a particular environment.
Variabilidad en el florecimiento de procedencias de Eucalyptus cladocalyx en la Región de Coquimbo
Mora,Freddy; Perret,Sandra; Scapim,Carlos Alberto; Nunes Martins,Elias; Molina,María Paz;
Ciencia e investigación agraria , 2007, DOI: 10.4067/S0718-16202007000200006
Abstract: this work aimed to study the variability in flowering of five populations of eucalyptus cladocalyx established in the administrative region of coquimbo, northern chile. flowering was recorded as a binary response trait in 30-month-old trees. then, at first, a generalized linear model was fitted for analyzing provenance effect. subsequently, genetic variability was studied within the best provenance by bayesian inference via gibbs sampling. initially, two sites were considered: caracas and tunga norte, in the littoral and interior area of the choapa province, respectively. in the littoral area, only 1.3% of the trees evidenced flowering events, while in tunga norte, this value was 23.43%. for this reason, only interior site was considered. the provenance effect was significant (p < 0.01), with cowell (codified fdi-20411) being the population that evidenced a relative better flowering response, although it not was different of the trees from national plantations (fdi-illapel). however, trees from a local population evidenced a high variability, having a mean response similar to other provenances. the flowering trait analyzed within the cowell population, the selected provenance, was shown to be highly heritable (h2 = 52.3%). predicted genetic gain when considering two different breeding strategies varied from 36 to 40%. according to these results, it is possible that farmers can recover establishment costs of e. cladocalyx plantations as soon as possible whenever the selected trees are used for apicultural aims
RETRACTED: Artefact in forensic medicine: The jigsaw piece in a thanatopsy puzzle  [PDF]
Freddy Patel
Forensic Medicine and Anatomy Research (FMAR) , 2013, DOI: 10.4236/fmar.2013.12002
Abstract:

Short Retraction Notice

The following article has been retracted due to the investigation of complaints received against it. The scientific community takes a very strong view on this matter and we treat all unethical behavior seriously. In making this decision the Editorial Board follows COPE's Retraction Guidelines. Aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused.

Editor guiding this retraction: Prof. Geoffrey Sperber (EB of FMAR)

The?full retraction notice?in PDF is preceding the original paper, which is marked \"RETRACTED\"

Dual formulation of classical W-algebras
Robert Perret
Physics , 1992, DOI: 10.1007/BF00739586
Abstract: By extending the concept of \mc, I introduce a dual formulation of (classical) nonlinear extensions of the \vir\ algebra. This dual formulation is closely related to three dimensional actions which are analogous to a \cs\ action. I present an explicit construction in terms of superfields of the $N=2$ super \wfour.
Three dimensional field theories from infinite dimensional lie algebras
Robert Perret
Physics , 1992, DOI: 10.1142/S0217751X94001643
Abstract: A procedure for constructing topological actions from centrally extended Lie groups is introduced. For a \km\ group, this produces \3al \cs, while for the \vir\ group the result is a new \3al \tft\ whose physical states satisfy the \vir\ \wi. This \tft\ is shown to be a first order formulation of two dimensional induced gravity in the chiral gauge. The extension to $W_3$-gravity is discussed.
A classical N=4 super W_3 algebra
Robert Perret
Physics , 1992, DOI: 10.1142/S0217751X93001478
Abstract: I construct classical superextensions of the Virasoro algebra by employing the Ward identities of a linearly realized subalgebra. For the $N=4$ superconformal algebra, this subalgebra is generated by the $N=2$ $U(1)$ supercurrent and a spin~0 $N=2$ superfield. I show that this structure can be extended to an $N=4$ super $W_3$ algebra, and give the complete form of this algebra.
b Physics
Pascal Perret
Physics , 1998, DOI: 10.1063/1.56620
Abstract: A summary of the most recent and important measurements in b physics is presented. The production of beauty particles in Z decays, b quark couplings, lifetimes, B0-B0bar oscillations, semileptonic b decays and studies of the number of charm quarks produced in b decays are reviewed. Extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |V_{td}|, |V_{cb}|, |V_{ub}| and implication for |V_{ts}| are discussed.
Status and Prospects for Heavy Flavour Physics at LHC
Pascal Perret
Physics , 2010,
Abstract: The Large Hadron Collider will be a unique place to find new physics in the next decade. A huge production of b and c quarks will allow a rich programme of Heavy Flavour Physics to be carried out either by the multipurpose experiments ATLAS and CMS or by LHCb, the experiment designed for such physics. An overview of the LHC machine and experiments' performances will be given with the first 2010 data. The start-up is very bright and some first LHC heavy flavour results will be presented. The b physics program at LHC will be illustrated with three examples: the searches for rare decays such as B_s -> mu mu, the CP measurements from B_s -> J/psi phi and CP measurements of the Cabibbo Kobayashi Maskawa (CKM) angle gamma. Some prospects for an upgrade of the LHCb detector will also be given.
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