Un milieu graphico-cinématique pour l’apprentissage des dérivées dans une praxéologie "modélisation" : potentialités et limites

Doctoral thesis (2012)

Ce travail concerne l’apprentissage du calcul des dérivées tel qu’étudié chez des élèves de 16-17 ans aux prises avec des questions mobilisant des mouvements rectilignes, leurs vitesses variables ou non ... [more ▼]

Ce travail concerne l’apprentissage du calcul des dérivées tel qu’étudié chez des élèves de 16-17 ans aux prises avec des questions mobilisant des mouvements rectilignes, leurs vitesses variables ou non et les graphiques de leurs lois de position.
On y analyse ces questions comme composantes d’un milieu et les formes embryonnaires que prend le savoir construit dans ce contexte. Cette recherche illustre en outre en quoi consiste une praxéologie de type « modélisation » et le type particulier de discours technologique susceptible de justifier les techniques mises au point à ce stade. [less ▲]

Milieux ouverts forestiers, lisières forestières et biodiversité: de la théorie à la pratique.

Book published by Service public de Wallonie (2011)

L'aspect de la forêt naturelle, dans laquelle ont évolué les espèces forestières actuelles pendant des milliers d'années, était probablement beaucoup plus ouvert que ce que l'on peut imaginer aujourd'hui ... [more ▼]

L'aspect de la forêt naturelle, dans laquelle ont évolué les espèces forestières actuelles pendant des milliers d'années, était probablement beaucoup plus ouvert que ce que l'on peut imaginer aujourd'hui, sous l'effet de perturbations diverses et de l'action des grands herbivores. Si les ouvertures en forêt sont désormais le plus souvent liées à l'action humaine, le potentiel biologique de ces milieux n'en est pas moins élevé grâce au développement de cortèges d'organismes héliophiles caractéristiques des faciès de régénération des forêts naturelles. Par ailleurs, les lisières, qu'elles soient situées en bordure de ces ouvertures intra-forestières ou en périphérie des massifs forestiers, contribuent dans une large mesure à l'intérêt biologique des zones ouvertes, pour peu qu'elles soient progressives et dynamiques. La co-existence de lisières et de différents types de milieux ouverts variant entre eux à la fois dans l'espace (taille, forme,...) et dans le temps (événements ponctuels, récurrents ou permanents) au sein d'un massif géré est un atout incontestable pour la biodiversité. Leur intérêt biologique est intimement lié à la structure et à la composition de la végétation et, partant, à leur mode d'exploitation et de gestion. Ce guide propose donc, au-delà d'une révision théorique sur le sujet, de nombreux conseils pratiques d'aménagement et d'entretien des ouvertures forestières, afin d'en optimiser la capacité d'accueil tout en interférant le moins possible avec la production sylvicole. [less ▲]

Military Cultures and Education: Harmonizing or Standardizing Europe?

in Univers Strategic - Revista Universitara Romana de Studii de Securitate (2010), 2(1), 274

Military Higher Education Stocktaking Report

Book published by EU Council DGF (Press) (2010)

This stocktaking report, drafted in collaboration with the EU Member States, their institutions and the European Security and Defence College aims at presenting a state of the art of the European officers ... [more ▼]

This stocktaking report, drafted in collaboration with the EU Member States, their institutions and the European Security and Defence College aims at presenting a state of the art of the European officers' educational systems and at supporting scientifically the implementation of the Initiative for the exchange of young officers, inspired by Erasmus, undertaken under the Franch EU Presidency (second semester 2008). [less ▲]

Milk and serum standard reference materials for monitoring organic contaminants in human samples

in Analytical and Bioanalytical Chemistry (2013), 405

Milk fat globule membrane and buttermilks: from composition to valorization

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(3), 485-500

Buttermilk, the by-product from butter manufacture, is low cost and available in large quantities but has been considered for many years as invaluable. However, over the last two decades it has gained ... [more ▼]

Buttermilk, the by-product from butter manufacture, is low cost and available in large quantities but has been considered for many years as invaluable. However, over the last two decades it has gained considerable attention due to its specific composition in proteins and polar lipids from the milk fat globule membrane (MFGM). The aim of this review is to take stock of current buttermilk knowledge. Firstly, the milk fat globule membrane composition and structure are described. Secondly, buttermilk and its associated products are defined according to the milk fat making process. Structure and mean composition of these products are summarized from recent dairy research data and related to technological properties, especially the emulsifying properties provided by MFGM components. Finally, new applications are presented, leading to promising valorizations of buttermilk and its derivate products. [less ▲]

Milk in a diet for growing-fattening bulls : Effects on animal performances and on meat characteristics

in Proceedings of the 45th Annual Meeting of E.A.A.P (1994)

Milk production and marketing in small dairy holders in the Northern area of Vietnam : a case study in Phu Dong

in Hanoi University of Agriculture; Francophone Joint University Council (CIUF) (Eds.) Proceedings of Scientific Research Results - Institutional University Cooperation Program 2008-2012 (2013)

Milk production correlates negatively with plasma levels of pregnancy-associated glycoprotein (PAG) during the early fetal period in high producing dairy cows with live fetuses

in Domestic Animal Endocrinology (2007), 32(1), 29-42

This study was designed to establish possible factors affecting plasma pregnancy-associated glycoprotein (PAG) concentrations during early pregnancy in high producing dairy cows with live fetuses. Blood ... [more ▼]

This study was designed to establish possible factors affecting plasma pregnancy-associated glycoprotein (PAG) concentrations during early pregnancy in high producing dairy cows with live fetuses. Blood samples were obtained on days 35, 42, 49, 56 and 63 of gestation from 80 lactating cows in two herds carrying live fetuses. Radioimmunoassay systems were used to determine PAG (RIA-497 and RIA-706) and progesterone concentrations. We evaluated the effects on PAG concentrations of herd, lactation number, sire of fetus, day of gestation, fetus number, plasma progesterone and milk production at each time point established, along with possible paired interactions. Mean milk production per cow approached 41 kg during the study period. PAG concentrations were not affected by herd, lactation number or plasma progesterone concentration. Significant positive effects on PAG concentrations were shown by the gestation day, and the interaction between day of gestation and twin pregnancy. Significant differences between bulls and a significant negative correlation between milk production and PAG values on day 63 of pregnancy were also detected. Proportions of blood samples showing undetectable PAG levels and false negative diagnoses throughout the study period were significantly higher (P < 0.001) using the RIA-497 system (2.5% and 5.3%, respectively) compared to RIA-706 (0% and 0.8%, respectively). Our findings suggest that PAG concentrations during the early fetal period are related to the day of gestation, milk production, number of fetuses and sire of fetus in high producing dairy cows. Under our working conditions, the RIA-706 method was better at detecting plasma PAG molecules than the RIA-497 system. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

Milk production of imported heifers and Tunisian-born Holstein cows

in American-Eurasian Journal of Agronomy (2009), 1(3), 36-42

Test day (TD) records of milk, fat and protein yields and somatic cell scores (SCS) were studied in Holstein cows in Tunisia. There were 43114, 32923 and 24633 lactation records collected on first, second ... [more ▼]

Test day (TD) records of milk, fat and protein yields and somatic cell scores (SCS) were studied in Holstein cows in Tunisia. There were 43114, 32923 and 24633 lactation records collected on first, second and third parity cows between 1992 and 2004 in 182 herds. Records were of cows born in Tunisia (22000 cows) and those imported from Europe (10830 cows) and North America (850 cows). Variation of total days in milk (DIM) per lactation was studied in function of the herd, calving year x calving season interaction and the origin of the cow. Test-day records were analyzed using a linear model that included calving year x calving season and herd x test-day date interactions, calving season, calving year and origin of the cow. The effective length of lactation was affected by all factors included in the model (p< 0.0001) in all lactations. Test- day milk, protein and fat yields and TD SCS varied (p< 0.01) with management and climatic factors (calving year x calving season and herd x test-day date interactions and year and season of calving). A cow produced 18.8 kg, 0.61 kg and 0.58 kg of milk, fat and protein yields on a daily basis in all lactations, respectively. Average SCS was 2.8 in the three lactations. The origin of the cow was an important (p < 0.05) source of variation for DIM, yields and SCS in all lactations except for first lactation cell scores (p>0.05). Cows born in Tunisia seemed to perform better than imported cows in the first lactation while imported cows showed clearly better performances in later lactations. North American cows produced the highest yields and had the lowest SCS among all cows in the second and third lactations. Imported high producing cows seemed able to adjust to Tunisian management conditions following their first lactation. [less ▲]