Variabilités de la Taille de Portée des Ovins

Study the variabilities the litter size in sheepCe travail de recherche a été mené dans l’équipe MODGEN du département GenPhySE, 1388 UMR de l’INRA. Il avait pour perspectives de modéliser les variabilités de la taille de portée des ovins pour une meilleure évaluation génétique et de proposer des modèles d’analyse adoptés à ce type de caractère.Les objectifs de l’étude étaient d'identifier, et d'analyser les facteurs environnementaux et génétiques des variabilités des tailles de portée des brebis et de proposer une méthode adaptée pour canaliser les caractères discretsqui prenne en compte conjointement des objectifs sur la moyenne et sur la variabilité du caractère. La thèse s’appuyait sur des données issues de la chaîne nationale de contrôle de performances en relation avec des organismes de sélection ovin qui sont particulièrement intéressés par les résultats de ces recherches (CORAM).Choix des racesNous avons considéré trois races dont les fréquences de la taille de portée sont plus ou moins élevées. La race Romane connue par sa forte prolificité ainsi des effectifs contrôlés importants a permis des analyses précises. Les deux autres races choisies sont la race Suffolk et la race Rouge de l’Ouest qui ont servi à tester les modèles sur des populations comportant de moins en moins de portées multiples. La taille de portée des ovins considérée comme une variable continueAu cours de l’étude, nous avons identifié et hiérarchisé les facteurs de variation environnementaux du niveau de prolificité et de de sa variance pour trois races ovines (Suffolk, Rouge de l’Ouest et Romane). Si les facteurs de variation environnementaux du niveau de prolificitéétaient déjà bien connus, peu de données concernaient les facteurs de variation environnementaux de la variance. Nous avons également estimé les paramètres génétiques du niveau de prolificité et de sa variance, ils sont cohérents entre eux. Les héritabilités estimées sur la moyenne sont faibles, en cohérences entre les trois races et avec des études antérieures. La non homogénéité des corrélations estimées par le modèle à deux étapes peut s’expliquer par la relation structurelle entre la moyenne et la variance sur l’échelle observée qui n'est pas prise en compte dans ce type d'analyse. A l'échelle d'une race, cette relation dépend de l’écart spécifique entre les seuils; elle est différente de la relation moyenne – variance observée pour l’ensemble des races et qui est calculée sur des données brutes. La taille de portée des ovins considérée comme une variable discrète Nous avons montré l’existence d’une variabilité d’origine génétique dans les trois races étudiées et nous avons montré que le modèle à seuils homothétique [HTM] s’ajustait mieux aux données et qu'il permettait de calculer conjointement l’effet génétique sur la moyenne et sur la variance. Nous avons aussi montré les limites de ce modèle et nous avons proposé une solution afin de donner un cadre plus général à son utilisation et l’utiliser dans les évaluations génétiques. Nous avons également identifié un critère de sélection pertinent qui permet de sélectionner les individus de même moyenne ayant des variances différentes.Nous avons proposé le modèle à seuils indépendants [ITM] ou le modèle multi caractères avec contrainte, ce modèle considère que chaque réalisation est un caractère. Nous avons montré la faisabilité de cemodèle sur les trois races. Ceci nous a permis de mettre en évidence les problèmes liés à la convergence du programme utilisé, et nous avons proposé d’implémenter ce modèle en modifiant le programme TM

Torque Testing System: Flowserve Corporation

Flowserve Corporation provides products and customer support to companies in the process industry for the design, testing, and manufacturing of mechanical seals. This includes, but is not limited to, companies concerned with power generation, fossil fuels, water resources, and chemical processing. In industries where fluid transportation is leveraged, mechanical seals have been utilized in pumps to increase performance. A mechanical seal is a design feature in pumps that seal the impeller housing and allow for little to no leakage. This technology is cutting edge and a considerable amount of research pertaining to the advantageous effects of specialized surface features is being pursued in order to enhance the performance characteristics of Flowserve’s mechanical seals. The purpose of the project was to design an improved torque measurement system to test the specialized features on the seal faces

Character process model for semen volume in AI rams: evaluation of correlation structures for long and short-term environmental effects

The objective of this study was to build a character process model taking into account serial correlations for the analysis of repeated measurements of semen volume in AI rams. For each ram, measurements were repeated within and across years. Therefore, we considered a model including three environmental effects: the long-term environmental effect, which is a random year* subject effect, the short-term environmental effect, which is a random within year subject* collection effect, and the classical measurement error. We used a four-step approach to build the model. The first step explored graphically the serial correlations. The second step compared four models with different correlation structures for the short-term environmental effect. We selected fixed effects in the third step. In the fourth step, we compared four correlation structures for the long-term environmental effect. The model, which fitted best the data, used a spatial power correlation structure for the short-term environmental effect and a first order autoregressive process for the long-term environmental effect. The heritability estimate was 0.27 (0.04), the within year repeatability decreased from 0.56 to 0.44 and the repeatability across years decreased from 0.43 to 0.37

Inference of abrupt changes in noisy geochemical records using transdimensional changepoint models

International audienceWe present a method to quantify abrupt changes (or changepoints) in data series, represented as a function of depth or time. These changes are often the result of climatic or environmental variations and can be manifested inmultiple datasets as different responses, but all datasets can have the same changepoint locations/timings. The method we present uses transdimensional Markov chain Monte Carlo to infer probability distributions on the number and locations (in depth or time) of changepoints, the mean values between changepoints and, if required, the noise variance associated with each dataset being considered. This latter point is important as we generally will have limited information on the noise, such as estimates only of measurement uncertainty, and in most cases it is not practical to make repeat sampling/measurement to assess other contributions to the variation in the data.Wedescribe themain features of the approach (and describe themathematical formulation in supplementary material), and demonstrate its validity using synthetic datasets, with known changepoint structure (number and locations of changepoints) and distribution of noise variance for each dataset.We show that when using multiple data, we expect to achieve better resolution of the changepoint structure than when we use each dataset individually. This is conditional on the validity of the assumption of common changepoints between different datasets.We then apply themethod to two sets of real geochemical data, both from peat cores, taken from NE Australia and eastern Tibet. Under the assumption that changes occur at the same time for all datasets, we recover solutions consistent with those previously inferred qualitatively from independent data and interpretations. However, our approach provides a quantitative estimate of the relative probability of the inferred changepoints, allowing an objective assessment of the significance of each change

Timing of Hepatic Artery Reperfusion and Biliary Strictures in Liver Transplantation

During orthotopic liver transplantation (OLT), biliary tract perfusion occurs with hepatic artery reperfusion (HARP), commonly performed after the portal vein reperfusion (PVRP). We examined whether the average time interval between PVRP and HARP impacted on postoperative biliary strictures occurrence. Patients undergoing OLT from 2007 to 2009 were included if they were ≥18 years old, had survived 3 months postoperatively, and had data for PVRP and HARP. Patients receiving allografts from DCD donors were excluded. Patients were followed for 6 months post-OLT. Seventy-five patients met the study inclusion criteria. Of these, 10 patients had a biliary stricture. There was no statistical difference between those with and without biliary stricture in age, gender, etiology, MELD score, graft survival, and time interval between PVRP and HARP. Ninety percent of patients with biliary stricture had a PVRP-HARP time interval >30 minutes, as opposed to 77% of patients without biliary stricture. However, this was not statistically significant. The cold ischemia time was significantly different between the two groups. Time interval for HARP after PVRP did not appear to affect the development of biliary strictures. However, 30 minutes may be suggested as a critical time after which there is an increase in biliary stricture occurrence

Genetic and environmental effects on semen traits in Lacaune and Manech tête rousse AI rams (Open Access publication)

Data from 51 107 and 11 839 ejaculates collected on rams of the "Lacaune" and "Manech tête rousse" breeds, respectively, were analysed to determine environmental and genetic factors affecting semen production traits (ejaculate volume, semen concentration, number of spermatozoa and motility) in young (≤1 year) and adult (≥2 years) rams. Fixed effects and variance components were estimated using multiple trait animal models within each breed. For all traits, the main environmental effects identified were year, season, number of ejaculations, daily variation, interval from previous to current collection and age. Heritability estimates were moderate for volume, concentration and number of spermatozoa (0.12 to 0.33) and lower for motility (0.02 to 0.14). Genetic correlations between ages differed from 1 for all traits (0.14 to 0.90), indicating that semen characteristics corresponded to different traits in young and adult rams. Genetic and phenotypic correlations among traits within age category were globally similar for the different breeds and categories of animals

Efecto del gen BMP15 sobre la distribución del tipo de parto en ovejas Rasa Aragonesa

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Relationship between the effects of the BMP15 gene and the polygenic effects on prolificacy in the rasa Aragonesa sheep breed

Los efectos del gen BMP15, localizado en el cromosoma X, sobre la media y la variabilidad de la prolificidad fueron estimados en la población Rasa Aragonesa, donde se analizaron 918.956 partos de ovejas de distintos genotipos (heterocigotas para el alelo FecXR o ROA®; y no portadoras). En primer lugar, se utilizaron modelos umbral que incluían o no el efecto del gen para estimar el efecto del genotipo BMP15 y su contribución a la variabilidad genética de la prolificidad en esta población. También se utilizaron otros dos modelos para estimar las interacciones entre el genotipo y los poligenes, así como el efecto del genotipo sobre la variabilidad de la prolificidad. Todos los análisis se hicieron con el programa ASReml. El efecto del genotipo sobre la media fue de 0,32 corderos adicionales por parto cuando el alelo ROA® se encontraba presente. Debido a que durante muchos años la selección por prolificidad en esta población se ha llevado a cabo desconociendo la presencia de esta mutación, los animales selectos portadores tienen un valor genético poligénico residual más bajo que los no portadores. No se encontró interacción significativa entre el genotipo y los efectos poligénicos sobre el valor genético. Aunque la interacción entre el genotipo y el conjunto de umbrales fue significativa, la diferencia entre ambos genotipos en la varianza de la prolificidad sobre la escala observada a una prolificidad media dada es escasa y muy poco relevanteThe effects of the BMP15 gene, located on the X chromosome, on mean prolificacy and its variability, were estimated in the Rasa Aragonesa sheep population through the analysis of 918,956 lambing records from ewes of different genotypes (FecXR or ROA® heterozygous ewes; and non-carrier ewes). Threshold models including or not the gene effect were first run to determine the effect of the BMP15 genotype and its importance in the total genetic variability of prolificacy. Two other models were also run to estimate the interaction between the BMP15 genotype and the polygenic background, as well as the effect of the genotype on the variability prolificacy. All the models were run using the ASReml software. The effect of the presence of the ROA® allele of the BMP15 gene on the mean prolificacy was 0.32 extra lambs per lambing. Due to the selection on prolificacy performed during many years in this population ignoring the presence of this major gene, animals carrying the mutation were found to have lower remaining polygenic estimated breeding values than non-carrier animals, and there was no interaction between the BMP15 genotype and the polygenic background. Although the interaction between the genotype and the set of thresholds was significant, the resulting between-genotypes difference of variance of prolificacy on the observed scale, at a similar mean litter size, was very low and not relevantPublishe

The capacitated general windy routing problem with turn penalties

In this paper we present the capacitated general windy routing problem with turn penalties. This new problem subsumes many important and well-known arc and node routing problems, and it takes into account turn penalties and forbidden turns, which are crucial in many real-life applications, particularly in downtown areas and for large vehicles. We provide a way to solve this problem both optimally and heuristically by transforming it into a generalized vehicle routing problem. © 2011 Elsevier B.V. All rights reserved.This work has been partially supported by the Ministerio de Educacion y Ciencia of Spain (project TIN2008-06441-C02-01). We are also indebted to the two anonymous referees for their valuable comments.Micó Ruiz, JC.; Soler Fernández, D. (2011). The capacitated general windy routing problem with turn penalties. Operations Research Letters. 39(4):265-271. https://doi.org/10.1016/j.orl.2011.04.007S26527139

The mixed capacitated general routing problem with turn penalties

In this paper we deal with the mixed capacitated general routing problem with turn penalties. This problem generalizes many important arc and node routing problems, and it takes into account turn penalties and forbidden turns, which are crucial in many real-life applications, such as mail delivery, waste collection and street maintenance operations. Through a polynomial transformation of the considered problem into a Generalized Vehicle routing problem, we suggest a new approach for solving this new problem by transforming it into an Asymmetric Capacitated Vehicle routing problem. In this way, we can solve the new problem both optimally and heuristically using existing algorithms. A powerful memetic algorithm and a set of 336 new benchmark instances are also suggested. The experimental results show that the average deviation of the suggested solution method is less than 0.05% with respect to optimum. © 2010 Elsevier Ltd. All rights reserved.This work has been partially supported by the Ministerio de Educacion y Ciencia of Spain (project TIN2008-06441-C02-01).Braysy, O.; Martínez Molada, E.; Nagata, Y.; Soler Fernández, D. (2011). The mixed capacitated general routing problem with turn penalties. Expert Systems with Applications. 38(10):12954-12966. https://doi.org/10.1016/j.eswa.2011.04.092S1295412966381