Combining farmers’ decision rules and landscape stochastic regularities for landscape modelling

Landscape spatial organization (LSO) strongly impacts many environmental issues. Modelling agricultural landscapes and describing meaningful landscape patterns are thus regarded as key-issues for designing sustainable landscapes. Agricultural landscapes are mostly designed by farmers. Their decisions dealing with crop choices and crop allocation to land can be generic and result in landscape regularities, which determine LSO. This paper comes within the emerging discipline called “landscape agronomy”, aiming at studying the organization of farming practices at the landscape scale. We here aim at articulating the farm and the landscape scales for landscape modelling. To do so, we develop an original approach consisting in the combination of two methods used separately so far: the identification of explicit farmer decision rules through on-farm surveys methods and the identification of landscape stochastic regularities through data-mining. We applied this approach to the Niort plain landscape in France. Results show that generic farmer decision rules dealing with sunflower or maize area and location within landscapes are consistent with spatiotemporal regularities identified at the landscape scale. It results in a segmentation of the landscape, based on both its spatial and temporal organization and partly explained by generic farmer decision rules. This consistency between results points out that the two modelling methods aid one another for land-use modelling at landscape scale and for understanding the driving forces of its spatial organization. Despite some remaining challenges, our study in landscape agronomy accounts for both spatial and temporal dimensions of crop allocation: it allows the drawing of new spatial patterns coherent with land-use dynamics at the landscape scale, which improves the links to the scale of ecological processes and therefore contributes to landscape ecology.     

Effects of fish stocking and fishing pressure on fish community structures in French lakes

Fish stocking and regulation of fishing activities are widely implemented by freshwater fisheries authorities who have to protect aquatic communities. The effects of fish management on fish communities have not received sufficient attention. As a result of two datasets, one from EU Water Framework Directive (WFD) monitoring surveys, and one from a French survey targeting angler's associations, this study investigated the impacts of both fishing intensity and fish stocking on fish communities in French lakes. Both co-inertia analysis and community size spectra analysis, showed that: (i) stocking does not contribute to the standing stocks for five of the six most stocked fish species in France; and (ii) neither fishing intensity nor fish stocking lead to a change in the proportion of large and small fish. The results support alternative methods being promoted to enhance native fish populations.     

Effects of whale watching on the activity budgets of humpback whales,Megaptera novaeangliae (Borowski, 1781), on a feeding ground

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Molecular basis of Mycoplasma agalactiae pathogenicity

Compared to other bacterial pathogens, the current knowledge of the molecular basis of pathogenicity of mycoplasmas is limited, and their strategies of infection at the molecular and cellular level remain to be elucidated. Several studies in the past years have shown that pathogenic mycoplasmas are equipped with sophisticated genetic systems, which allow these agents to spontaneously change their surface antigenic make-up. It is implicated that these variable surface components provide the wall-less mycoplasmas with a means to avoid the host immune response and promote host colonization. In Mycoplasma (M.) agalactiae, the agent of "contagious agalactia" in sheep and goats, a pathogenicity island-like locus has recently been identified that contains six distinct but related genes which encode the major immunodominant membrane proteins, the so-called Vpmas. It was shown that these surface-associated proteins vary in expression at an unusual high frequency due to site-specific DNA rearrangements. The previous lack of tools to genetically manipulate M. agalactiae has hampered more refined studies to assess the exact function of Vpmas in M. agalactiae infection and disease. The recent successful introduction of foreign DNA into the M. agalactiae genome therefore represents an important breakthrough which sets up the basis for a variety of follow-up studies assessing the role of Vpmas in molecular pathogenesis.     

Comparative analysis of Marek's disease virus (MDV) glycoprotein-, lytic antigen pp38- and transformation antigen Meq-encoding genes: association of meq mutations with MDVs of high virulence

Marek's disease (MD) is a highly contagious lymphoproliferative and demyelinating disorder of chickens. MD is caused by Marek's disease virus (MDV), a cell-associated, acute-transforming alphaherpesvirus. For three decades, losses to the poultry industry due to MD have been greatly limited through the use of live vaccines. MDV vaccine strains are comprised of antigenically related, apathogenic MDVs originally isolated from chickens (MDV-2), turkeys (herpesvirus of turkeys, HVT) or attenuated-oncogenic strains of MDV-1 (CVI-988). Since the inception of high-density poultry production and MD vaccination, there have been two discernible increases in the virulence of MDV field strains. Our objectives were to determine if common mutations in the major glycoprotein genes, a major lytic antigen phosphoprotein 38 (pp38) or a major latency/transformation antigen Meq (Marek's EcoRI-Q-encoded protein) were associated with enhanced MDV virulence. To address this, we cloned and sequenced the major surface glycoprotein genes (gB, gC, gD, gE, gH, gI, and gL) of five MDV strains that were representative of the virulent (v), very virulent (vv) and very virulent plus (vv+) pathotypes of MDV. We found no consistent mutations in these genes that correlated strictly with virulence level. The glycoprotein genes most similar among MDV-1, MDV-2 and HVT (gB and gC, approximately 81 and 75%, respectively) were among the most conserved across pathotype. We found mutations mapping to the putative signal cleavage site in the gL genes in four out of eleven vv+MDVs, but this mutation was also identified in one vvMDV (643P) indicating that it did not correlate with enhanced virulence. In further analysis of an additional 12 MDV strains, we found no gross polymorphism in any of the glycoprotein genes. Likewise, by PCR and RFLP analysis, we found no polymorphism at the locus encoding the pp38 gene, an early lytic-phase gene associated with MDV replication. In contrast, we found distinct mutations in the latency and transformation-associated Marek's EcoRI-Q-encoded protein, Meq. In examination of the DNA and deduced amino acid sequence of meq genes from 26 MDV strains (9 m/vMDV, 5 vvMDV and 12 vv+MDVs), we found distinct polymorphism and point mutations that appeared to correlate with virulence. Although a complex trait like MDV virulence is likely to be multigenic, these data describe the first sets of mutations that appear to correlate with MDV virulence. Our conclusion is that since Meq is expressed primarily in the latent/transforming phase of MDV infection, and is not encoded by MDV-2 or HVT vaccine viruses, the evolution of MDV virulence may be due to selection on MDV-host cell interactions during latency and may not be mediated by the immune selection against virus lytic antigens such as the surface glycoproteins.     

The Zodiak workshop: an innovative model for teaching financial management through partnership with industry

The National Commission on Veterinary Economic Issues (NCVEI) is working to enhance the non-technical skills, knowledge, aptitudes, and attitudes (SKAs) of veterinarians. This report describes the development of an innovative model for teaching the principles of financial management as they apply to the veterinary practice. Zodiak: The Game of Business Finance and Strategy is a "business literacy" game in which players work together in small teams (generally four people) to run a fictional multi-million-dollar company called Zodiak Industries for three "years" in order to learn principles of business finance and strategy. After finishing the 4.5-hour game, participants spend the rest of the workshop making the right "Connections"-exercises designed to connect what they have learned to business strategies, financial statements, and operational tactics drawn from veterinary practice. Issues addressed for the veterinary practice, with parallels drawn to Zodiak, included return on owner investment in a veterinary practice (vs. salary drawn by owner veterinarians); pricing (setting prices, price elasticity of demand, and relationships between volume, quality, and price); human resources and operations management as they relate to profitability and efficiency; cash flow and management of accounts receivable; and commonly used financial benchmarks. Workshop venues have included Michigan State University, The Ohio State University, the University of Illinois, and Purdue University. Financial and in-kind support were provided through partnership with Pharmacia Animal Health (now Pfizer Animal Health) and Hill's Pet Nutrition, Inc. Through course evaluations, participants generally rated the workshop high as an educational experience and indicated that the most important things learned were related to financial management (principles, terminology, and methods). The most enjoyable aspects of the workshop tended to be group discussions, teamwork, the dynamic/interactive environment, and the "game" atmosphere. Based on these experiences, the Zodiak workshop provides a useful model for teaching career development and practice management topics to veterinary students. The business simulation in a workshop format was especially useful for teaching these "non-mainstream" topics, as traditional classroom lecture approaches might not have engaged students sufficiently to achieve effective learning. In addition, the partnership developed between academia and industry offered substantial benefits to both parties. Similar educational approaches should be considered for additional aspects of the non-technical SKAs.     

Hereditary equine regional dermal asthenia ("hyperelastosis cutis") in 50 horses: clinical, histological, immunohistological and ultrastructural findings

Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin and shortened collagen fibres arranged in clusters in the deep dermis was suggestive of the disease. Trichrome, acid orcein-Giemsa and immunohistochemical stains for collagens I and III showed no consistent abnormalities compared to control horses; an increase in elastic fibres was not a consistent finding. Electron microscopy showed no abnormalities in the periodicity of the collagen bundles; neither orientation nor variation of cross-section diameter of the collagen fibrils differentiated control from affected horses. The diagnosis of HERDA relies on clinical presentation, but may be supported by suggestive (although not pathognomonic) histopathological lesions.