Performance comparison of laying hens segregating for the frizzle gene under thermoneutral and high ambient temperatures

Chantier qualité GAThe effect on thermotolerance of the incompletely dominant frizzle (F) gene, which causes feather curling and feather mass reduction, was investigated in 281 laying hens that were homozygous for the frizzle mutation (FF), heterozygous (FN), or normally feathered (NN). One-half of the birds were kept under standard conditions (22°C) and half were exposed to high ambient temperatures (32°C) between 24 and 46 wk of age. Egg production, egg quality, feed efficiency, and dissection traits were recorded and compared. At standard conditions, egg production and quality traits did not differ among the 3 genotypes, whereas feed efficiency was lower for the homozygous birds. Under heat stress conditions, the superiority of the FF hens was evident for all egg quantity and quality traits. No significant difference was measured between heterozygous carriers and normally feathered hens, indicating that the incomplete dominant frizzle mutation behaved as a recessive mutation regarding heat tolerance. From this study, we deduced that the F mutation in its homozygous state has a beneficial effect in decreasing heat stress in poultry production, and it could be particularly advantageous in tropical countries where average temperatures are never too low to negatively affect feed efficiency

The effect of the Frizzle (F) gene on egg production traits under standard and high ambient temperature

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Surface Heterogeneity, Physical, and Shape Model of Near-Earth Asteroid (52768) 1998 OR2

peer reviewedOn 2020 April 29, the near-Earth object (52768) 1998 OR2 experienced a close approach to Earth at a distance of 16.4 lunar distances (LD). 1998 OR2 is a potentially hazardous asteroid of absolute magnitude H = 16.04 that can currently come as close to Earth as 3.4 LD. We report here observations of this object in polarimetry, photometry, and radar. Our observations show that the physical characteristics of 1998 OR2 are similar to those of both M- and S-type asteroids. Arecibo's radar observations provide a high radar albedo of sigma _OC = 0.29 ± 0.08, suggesting that metals are present in 1998 OR2 near-surface. We find a circular polarization ratio of μc = 0.291 ± 0.012, and the delay-Doppler images show that the surface of 1998 OR2 is a top-shape asteroid with large-scale structures such as large craters and concavities. The polarimetric observations display a consistent variation of the polarimetric response as a function of the rotational phase, suggesting that the surface of 1998 OR2 is heterogeneous. Color observations suggest an X-complex taxonomy in the Bus–DeMeo classification. Combining optical polarization, radar, and two epochs from the NEOWISE satellite observations, we derived an equivalent diameter of D = 1.80 ± 0.1 km and a visual albedo pv = 0.21 ± 0.02. Photometric and radar data provide a sidereal rotation period of P = 4.10872 ± 0.00001 hr, a pole orientation of (332.°3 ± 5°, 20.°7 ± 5°), and a shape model with dimensions of ({2.08}_{-0.10}^{+0.10}, {1.93}_{-0.10}^{+0.10},{1.60}_{-0.05}^{+0.05}) km

Pratiquer les sciences sociales au Maghreb

Professeur de philosophie à l’Université de Fès, Driss Mansouri (1949-2012) est venu aux sciences sociales (anthropologie, histoire, linguistique, psychologie) dans le cadre de ses activités militantes. Dans une perspective de critique épistémologique, il n’a cessé par de nombreux articles de réfléchir sur leur orientation. Ce large recueil de contributions en trois langues (français, arabe, anglais), émanant de chercheurs d’âges et de formations différentes, ressortissants de huit nationalités, témoigne du rayonnement de notre ami disparu. Rassemblé à sa mémoire autour d’un thème cohérent, il entend dire la largeur de ses préoccupations, l’exigence d’une recherche généreuse autant que rigoureuse, où il apparaît comme un modèle. C’est l’occasion d’essayer un bilan d’étape sur les enquêtes qui se conduisent aujourd’hui au Maghreb. Le recueil est complété d’un choix de ses contributions.إدريس المنصوري (1949-2012) : أستاذ الفلسفة بكلية الآداب ظهر المهراز - فاس، مارس العلوم الاجتماعية (الأنثروبولوجيا والتاريخ، والسوسيولوجيا واللغويات، وعلم النفس) كجزء من نشاطه الفكري والنضالي، وتابع إنتاجها المغاربي من منظور إبستيمولوجي نقدي في العديد من المقالات. يضم هذا الكتاب مساهمات مكتوبة في ثلاث لغات (الفرنسية والعربية والإنجليزية)، شارك بها باحثون من أعمار مختلفة ومن ثمان جنسيات، تكريما لذكراه، مما يعكس بدون شك إشعاع صديقنا الراحل. وقد اتسقت حول موضوع يعكس سعة اهتماماته واطلاعه، وحرية فكره، ودقة أبحاثه. كانت هذه فرصة كذلك للقيام بحصيلة مرحلية للأبحاث التي تُجرى اليوم في أرض المغارب. يضم الكتاب أيضا مجموعة مختارة من إسهاماته

Value of biomarkers for predicting immunoglobulin A vasculitis nephritis outcome in an adult prospective cohort

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