HAL Université de Tours
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Effects of dietary calcium and microbial phytase on the bioavailability of two sources of zinc in broilers
No full textInternational audience1. The objective of this study was to test the effect of microbial phytase and calcium (Ca) levels on the Zn bioavailability depending on the Zn source.2. A total of 144, one-day-old broilers received a diet containing 40 mg Zn/kg for 1 week. They were then assigned to one of the eight experimental treatments during 2 weeks. Diets contained 27 mg native Zn and were formulated according to a 2 × 2 × 2 factorial design with two added Zn sources (23 mg Zn/kg), sulphate (ZnSO4) or oxide (ZnO); two dietary Ca levels of either 6 (low) or 10 g/kg (moderate); and two microbial phytase levels, of either 0 or 750 phytase unit/kg.3. Moderate Ca plus phytase improved body weight gain (BWG) and low Ca level without microbial phytase decreased tibia weight (Ca × Phy; p = 0.049). Zinc oxide resulted in a higher tibia development (i.e. tibia weight and length; p < 0.05) and BWG (p = 0.009) and lower FCR (p < 0.001) compared to ZnSO4.4. Phytase improved tibia Zn concentration especially in birds given ZnSO4 compared to ZnO (Zn × Phy; p = 0.049). Moderate Ca diets improved tibial characteristics and Zn deposition compared to low Ca diets (p < 0.05).5. Soluble Zn in the gizzard increased in the presence of phytase (p = 0.011), while higher dietary Ca reduced this in birds receiving ZnO (p = 0.004). In the jejunum, Zn solubility was higher with phytase (p = 0.008).6. Under the conditions of this study, dietary levels of Ca and microbial phytase affect Zn availability in broilers more than the Zn source
Manifestations of chiral anomaly in a graphene plate
No full textInternational audienceInspired by Son's model for graphene, we consider a -dimensional fermionic system in which fermions are described by four-component spinors. These fermions are proposed to interact with an electromagnetic field originating from a four-dimensional setting, as the graphene plate is embedded in 4d Minkowski spacetime. In this framework, a chiral anomaly arises at the boundary of the plate, stemming from a non-local anomaly action that depends on both the electromagnetic and chiral gauge fields when the chiral transformation is localized. This results in boundary chiral and electric currents, and we explore potentially observable effects when external magnetic or electric fields are applied to the fermionic system
Halogen-regulating synthesis of a novel semiconductor hybrid material [(CH3)3N(CH2)3Br]2ZnBr4 with high-temperature phase transition
No full textInternational audienceThe continuous progress in the synthesis and characterization of materials in the vast family of hybrid organic-inorganic metal halide perovskites have been pushed by their exceptional properties mainly in optoelectronic applications. Here, we have used specific reagents to design and synthesize a low dimensional semiconductor material, [Br(CH 2 ) 3 N(CH 3 ) 3 ] 2 ZnBr 4 using slow evaporation method which is crystalized in a monoclinic system with a P2/c space group with cell parameters of a = 23.572 ( 3) Å, b = 9.4987 (10) Å, c = 15.8731 (16) Å, b = 91.440 (4)1 and Z = 6 at room temperature. The crystal structure of [Br(CH 2 ) 3 -N(CH 3 ) 3 ] 2 ZnBr 4 was determined to be zero-dimensional (0D). In this structure, the inorganic [ZnBr 4 ] 2À anions are completely isolated from each other. These anionic groups are separated by [Br(CH 2 ) 3 N(CH 3 ) 3 ] + cations. The UV-visible absorption spectrum of the polycrystalline sample estimates the band gap, which was found to be approximately 3.36 eV. Differential scanning calorimetric analysis exhibits one irreversible phase transition at 358 K. The XRD as function of the temperature confirms this transition by the change of the symmetry of this material. The temperature-dependent Raman scattering study analyzed in detail the full width at half-maximum (FWHM) of internal modes of the anions and cations which are connected by intermolecular C-HÁ Á ÁBr hydrogen bonds and an intramolecular C-HÁ Á ÁBr interaction. The change of energy activation confirms the phase transition. The electrical properties further validate the transition mechanism through the observed change in energy activation using the variation of the conductivity versus temperature
L’impact des niveaux de revendication territoriale régionale sur l’intention d’achat de produits alimentaires : Le rôle médiateur de la valeur perçue
No full textInternational audienceThis research focuses on consumer perceptions of the territorial claims made by a region brand on food product packaging. The aim is to study the impact of territorial claims–weak (simple mention of the place) and strong (label set up by the region to meet demanding specifications)–on purchase intention via perceived value. An experiment involving 186 respondents and manipulating the level of territorial claim (absence vs. weak vs. strong) shows that emotional perceived value mediates the impact of the presence of a territorial claim on purchase intention. However, this positive impact is no greater when the claim is strong. Thus, a weak territorial claim improves levels of perceived value (emotional dimension) and purchase intention just as much as a claim that justifies an accreditation process. However, a strong claim generates higher levels of price and social value than a weak claim.Cette recherche s’intéresse aux perceptions des consommateurs vis-à-vis des revendications territoriales proposées par une marque région sur les packagings de produits alimentaires. Il s’agit d’étudier l’impact des revendications territoriales – faible (simple mention du territoire) et forte (label mis en place par la région répondant à un cahier des charges exigeant) – sur l’intention d’achat via la valeur perçue. Une expérimentation auprès de 186 répondants et manipulant le niveau de revendication territoriale (absence vs. faible vs. forte) montre que la valeur perçue émotionnelle médiatise l’impact de la présence d’une revendication territoriale sur l’intention d’achat. En revanche, cet impact positif n’est pas plus important lorsque la revendication territoriale est forte. Ainsi, une revendication territoriale faible améliore tout autant les niveaux de valeur perçue (dimension émotionnelle) et d’intention d’achat qu’une revendication justifiant d’une démarche d’accréditation. Une revendication forte amène cependant des niveaux de valeur prix et sociale plus importants qu’une revendication faible
Isospin precession in non-Abelian Aharonov-Bohm scattering
No full textThis paper is dedicated to the memory of “Tai” (Tai-Tsun Wu : 1933-2024)International audienceThe concept of pseudoclassical isospin is illustrated by the non-Abelian Aharonov-Bohm effect proposed by Wu and Yang in 1975. The spatial motion is free however the isospin precesses when the enclosed magnetic flux and the incoming particle's isosopin are not parallel. The non-Abelian phase factor of Wu and Yang acts on the isospin as an S-matrix. The scattering becomes side-independent when the enclosed flux is quantized, with an integer. The gauge group is an internal symmetry and generates conserved charges only when the flux is quantized, which then splits into two series: for acts trivially but for the implementation is twisted. The orbital and the internal angular momenta are separately conserved. The double rotational symmetry is broken to when odd. For unquantized flux there are no internal symmetries, the charge is not conserved and protons can be turned into neutrons
Onze siècles d'établissements agropastoraux sur les bords de l'Indre à Veigné « Vaugourdon » (Indre-et-Loire)
No full textSynthèse monographique (livret illustré) qui présente les résultats de la fouille préventive Inrap du site de Vaugourdon à Veigné (Indre-et-Loire)International audienceLe passage en 2 x 3 voies de l’autoroute A10 entre les communes de Veigné et Sainte-Maure-de-Touraine (Indre-et-Loire) a donné lieu à huit prescriptions de diagnostics archéologiques par l’État. Ceux-ci ont été réalisés entre 2018 et 2019 et ont été suivis de deux fouilles préventives engagées en 2020 dans les communes de Saint-Épain et Veigné. Sur cette dernière, au lieu-dit « Vaugourdon », les 1,8 hectares explorés correspondent à une zone de compensation écologique localisée entre la route de Beaupré et le ruisseau de Roulecrotte, un bras actif de l’Indre. La fouille a livré plus de 800 faits archéologiques qui couvrent une large fourchette chronologique comprise entre 1 600 av. J-C (âge du Bronze) et l’époque contemporaine. Néanmoins, les installations les plus denses et les plus structurées concernent principalement les onze premiers siècles de notre Ère, c’est-à-dire l’Antiquité au sens large et le premier Moyen Âge. Dans cet espace temps, se succèdent ainsi, possiblement sans hiatuschronologique, une villa romaine et un habitat du haut Moyen Âge
Experimental evidence of pollination by deception in a dioecious palm
No full textInternational audienceBackground: Flower traits and pollinator activity patterns can vary over the course of a single day. Therefore, the pollination processes occurring over short time scales are crucial to sustain the complex dynamics of plant-pollinator interactions. Here, we characterized the diel patterns of flower opening (e.g. anthesis), scent emission, and insect visits in highly dimorphic male (rewarding) and female (deceptive) inflorescences of the ivory palm (Phytelephas aequatorialis), a thermogenic dioecious species endemic to western Ecuador. We conducted field experiments using artificial scented-baits (designated as artificial flowers) consisting of a heating plate (simulating thermogenesis) and p-methylanisole (the primary odor compound in inflorescences of both sexes) in two different amounts to mimic female and male inflorescences.Results: We found that female inflorescences open synchronously at dawn and dusk, while male inflorescences can open at any time throughout the day. Both sexes emitted floral odors consistently throughout the day. Even though male inflorescences emitted greater quantities of p-methylanisole, artificial flowers with different amounts of p-methylanisole attracted a similar diversity and abundance of insects throughout the day. Furthermore, male and female artificial flower attracted an equal abundance of visitors within five minutes of the emission of p-methylanisole.Conclusions: The findings suggest that, despite sexual dimorphism in opening time, intersexual mimicry in P. aequatorialis is sustained by a consistent odor release, which optimizes the probability of both sexes being visited by the same insect community during the day
1340-1610. Figures de la fortune dans la Renaissance européenne : entre hasard et Providence
No full textInternational audiencePourquoi aimons-nous le hasard, et quel rôle joue cette attirance dans notre compréhension du monde ?Depuis la Renaissance, l’Occident ne cesse de redécouvrir l’aléatoire ; chaque époque annonce une nouvelle ère de la contingence. À l’émerveillement ou l’inquiétude succèdent alors le doute (n’est-il que le produit de notre ignorance ?) puis la résignation : il n’y a, au fond, pas de hasard. L’intérêt qu’il suscite s’explique donc par le gain de connaissance que l’on peut en attendre. Un phénomène inexplicable montre l’insuffisance de nos descriptions du monde et nous donne ainsi une chance d’accéder à un nouveau paradigme scientifique, où le hasard n’a plus de place – jusqu’à l’apparition de l’irrégularité suivante.Mais dans cette transition entre deux certitudes, nous prenons le temps de reconnaître l’importance unique de ce qui n’a pas de cause, et la beauté de ce qui n’est apparemment produit par rien. Ce livre est consacré à l’exploration de ce moment suspendu entre l’ignorance et le savoir, que nous remplissons d’images, d’histoires, de jeux et de théories qui modélisent notre rapport essentiel à la contingence.IntroductionOUVERTURE DE LA RENCONTREAUTOUR DE LA FORTUNE ÉMERGENCE D'UN CHAMP LEXICALDU HASARD, DU XIV AU XVI SIÈCLE -- La fortune, figure dominante et équivoque -- Une ambivalence structurante -- L'essor d'une axiologie positive -- La formation de nouvelles notions abstraites.LA FORTUNE EN DÉBATS ET EN PRATIQUES (XIV-XVI SIÈCLES) -- Fortune, hasard et Providence dans les textes d'idées :entre réception des philosophies antiques et querelles théologiques -- La part du hasard dans l'écriture de l'histoire -- Hasard et société la Fortune est-elle aveugle ?HASARD ET CRÉATION AU XVI SIÈCLE RÉCIT, THÉÂTRE, TOPIQUE -- Le sillage d'Apelle -- Le récit de fiction entre fortune et providence auctoriales -- Les jeux de l'humaine fortune: hasard et théâtre (1540-1630) -- Arranger, annuler ou maitriser le sortCONCLUSIO
Transcribing Western modern manuscripts (1500-2020): An economical, ecological and secured approach
No full textInternational audienceWe present a massive model for Western cursive hands. The model shows good performances used from scratch, and even excellent ones when being fine tuned. Entirely open, it is a flexible and efficient solution for projects with limited funding or strict security requirements
