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71.
Vincent Plassard Amaury Briand Eve Laloy Jean-Marie Gourreau Didier Pin Yves Millemann 《Veterinary dermatology》2021,32(2):196-199
This report describes an outbreak of hairy vetch toxicosis afflicting a herd of cattle with a fatal cutaneous and systemic granulomatous disease. It highlights how this condition remains poorly recognized by cattle production professionals in Europe and the need for communication about vetch-associated diseases. 相似文献
72.
Domenica Manicacci Isabelle Olivieri Véronique Perrot Anne Atlan Pierre-Henri Gouyon Jean-Marie Prosperi Denis Couvet 《Landscape Ecology》1992,6(3):147-159
Distribution of genetic diversity in a landscape depends on both within and among population processes. Selective pressures within populations have traditionally been studied by population genetics, which usually assumes that populations are at equilibrium. However, when selection pressures within and among populations are different, landscape processes are required to define an equilibrium (landscape being defined as the habitat of a set of populations called a metapopulation, and populations will differ depending on their situation in the landscape, i.e. their age and the state of neighboring populations). We examine reproduction systems and life history traits, for which variation depends on landscape processes. Predictions of their states in a metapopulation are drawn from theoretical models, and confronted to observations collected in natural populations. 相似文献
73.
The delivery of CD4 help to CD8+ T cell responses requires interactions between CD40 and CD40 ligand and is thought to occur through antigen-presenting cell (APC) activation. Here we show that generation of memory CD8+ T cells displaying an enhanced capacity for cell division and cytokine secretion required CD4 help but not CD40 expression by the APCs. Activated CD4+ and CD8+ T cells expressed CD40; and in the absence of this protein, CD8+ T cells were unable to differentiate into memory cells or receive CD4 help. These results suggest that, like B cells, CD8+ T cells receive CD4 help directly through CD40 and that this interaction is fundamental for CD8+ T cell memory generation. 相似文献
74.
Toward self-organization and complex matter 总被引:1,自引:0,他引:1
Lehn JM 《Science (New York, N.Y.)》2002,295(5564):2400-2403
Beyond molecular chemistry based on the covalent bond, supramolecular chemistry aims at developing highly complex chemical systems from components interacting through noncovalent intermolecular forces. Over the past quarter century, supramolecular chemistry has grown into a major field and has fueled numerous developments at the interfaces with biology and physics. Some of the conceptual advances and future challenges are profiled here. 相似文献
75.
This paper focuses on the environmental and ethical attributes of food products and their production processes. These two aspects have been recently recognized and are becoming increasingly important in terms of signaling and of consumer perception. There are two relevant thematic domains: environmental and social. Within each domain there are two movements. Hence the paper first presents the four movements that have brought to the fore new aspects of food product quality, to wit: (1) aspects of environmental ethics (organic agriculture and integrated agriculture), and (2) social ethics (fair trade and ethical trade). Next, it describes how the actors in the movements (producers, retailers, NGOs, and governments) are organized and how consumers perceive each of the movements. From the perspective of the actors in the movements themselves, the movements are grouped into two “actors’ philosophies.” The first is a “radical” philosophy (the organic production and fair trade movements that arose in radical opposition to conventional agriculture or unfair trade relations), and the second is a “reformist” philosophy (the integrated agriculture and ethical trade movements that arose as efforts to modify but not radically change conventional agriculture). From the point of view of consumers, the classification of the movements is based on perceptions of the “domain” of the movements. That is, consumers tend to perceive the organic production movement and the integrated agricultural movement as a single group because they both deal with the environment. By contrast, consumers tend to group the fair trade movement and the ethical trade movement together because they both deal essentially with social ethics. Recently, key players such as large retailers and agribusinesses have adopted as part of their overall quality assurance programs both environmental and ethical attributes. Their involvement in and adoption of the goals of the movements have, however, generated tensions and conflicts. This is particularly true within the radical movements, because of concerns of cooptation. Finally, the paper identifies challenges faced by those promoting food products with environmental and social/ethical attributes as they attempt to communicate coherent signals to consumers at this crucial moment in the emergence of a mass market for these products.
Jean
-Marie Codron
is a Senior Researcher at INRA and co-director of MOISA, a public joint research laboratory involved in the social sciences. His research interests focus on three main lines of research: economics of contracts, economics of the firm, and economics of market institutions, with applications to “complex” food sectors, where product quality is difficult to measure and/or to signal to the consumer.
Lucie Sirieix
is Professor of Marketing and Consumer Behaviour at SupAgro Montpellier, France, a national higher education establishment under the Ministry of Agriculture, Fisheries and Food. Within the MOISA research unit, her main research topics are variety seeking, risk and trust, environmental and ethical consumer concerns, and sustainable consumption. Her specific research areas include organic products, fair trade, and regional products.
Thomas Reardon
is Professor of Agricultural Economics at Michigan State University. His work focuses on globalization, consolidation in the retail and processing sectors, and their effects on agrifood systems and trade as well as on the economics of private quality and safety standards. 相似文献
76.
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78.
Hernandez V Albini T Lee W Rowaan C Nankivil D Arrieta E Parel JM 《Veterinary ophthalmology》2012,15(3):141-144
Objective To demonstrate a cost‐effective, portable, and simple‐to‐use fundus imaging system for laboratory animals. Animals Studied Albino rats, pigmented mice, albino guinea pigs, and New Zealand white rabbits. Procedure A contact fundus imaging system was designed and constructed using standard optical and mechanical components: a digital camera, an otoscope, a fiber optic light source, and standard optical lenses and mounts. Digital fundus video and photography of two albino rats, two pigmented mice, two New Zealand white rabbits, and two albino guinea pigs were obtained. For all animals examined, pupils were dilated and local anesthetic was administered. Results Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, as the axial length, ocular optics, and retinal reflectance varied significantly across species. Light intensity and focus were optimized via the light source and lens focusing mount to produce high‐quality images for each animal. Conclusions The portable, cost‐effective contact fundus imaging system was easy to use for fundus examination of laboratory animals. 相似文献
79.
Stéphanie Bourgeois 《Biological conservation》2009,142(1):85-93
The coast of Gabon is one of the most important nesting sites for the endangered leatherback sea turtle Dermochelys coriacea. In this study, hatchling orientation was recorded during natural emergences at Pongara National Park, Gabon. This nesting beach is located close to both the capital of Gabon and a developing resort area, Pointe Denis. Under natural conditions most sea turtle hatchlings emerge at night and orient to the ocean by crawling away from dark, high silhouettes landward towards the bright, low seaward horizons. Artificial lights interfere with natural cues and disrupt hatchling orientation. The relative influence of artificial lights, logs and erosion were assessed on the nesting beach in Pongara National Park using a linear mixed model. We found that the attraction to artificial lights was higher than the effect of silhouette cues landward alone, but could be balanced by the simultaneous presence of the moon. Based upon these results, we recommend combining light management in the resort area to reduce the light pollution on the nesting beach and reinforcement of natural cues landward to minimize the effect of the remaining light pollution from the capital. 相似文献
80.
Jean-Philippe Lejeune DVM Fabrice Audigie DVM PhD Nicole Schneider DVM Dominique Duvivier DVM PhD Jackie Tapprest DVM Jean-Marie Denoix DVM PhD Didier Serteyn DVM PhD 《Journal of Equine Veterinary Science》2006,26(3):102-112
The anatomic variations and the degenerative changes in the collateral cartilages and middle and distal phalanges in 6 Ardenner colts were characterized by radiography, scintigraphy, and magnetic resonance imaging (MRI). The radiographic changes were assessed between the ages of 16.5 and 25 months. An anatomic variation of the middle and distal phalanges was demonstrated in some of the colts. MRI examination of the 6 colts revealed an association between the deep digital flexor tendon cross-sectional area and body weight as well as foot circumference. Also, a thin collateral sesamoidean (suspensory navicular) ligament was observed subjectively. The presence of an extensive ossification of the collateral cartilages of the foot was found in these young horses. The ossification was characterized by the existence of 2 separate ossification centers, which had a tendency to unite. The radiographic interphalangeal degenerative lesions seen appear as bone remodeling of the dorsal edges of the middle and distal phalanx, on the insertion sites of collateral ligaments of the distal interphalangeal joint, the digital extensor tendon, and the distal interphalangeal joint capsule. 相似文献