Survey on Salmonella prevalence in slaughter pigs from Saskatchewan     

Mainar-Jaime RC  Atashparvar N  Chirino-Trejo M  Rahn K 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(8):793-796

A study on slaughter pigs from Saskatchewan detected Salmonella organisms in 12.5% and 5.2% of cecal content and ileocaecal lymph node samples, respectively. Cecal content prevalence was associated with larger farms and longer lairage periods. Antimicrobial resistance was detected in 41.5% of the isolates. Salmonella Enteritidis was the second most prevalent serotype.  相似文献   

Persistent changes in forest vegetation and seed bank 1,600 years after human occupation   总被引：1，自引：1，他引：0  

Jan Plue  Martin Hermy  Kris Verheyen  Patrice Thuillier  Robert Saguez  Guillaume Decocq 《Landscape Ecology》2008,23(6):673-688

Past land use is an important factor determining vegetation in temperate deciduous forests. Little is known about the long-term persistence of these impacts on vegetation but especially on the seed bank. This study assessed whether soil characteristics remain altered 1,600 years after human occupation and if this yielded persistent differences in forest plant communities and their seed bank in particular. Compiègne forest is located in northern-France and has a history of continuous forest cover since the end of Roman times. Twenty-four Gallo-Roman and 24 unoccupied sites were sampled and data were analysed using paired sample tests to investigate whether soil, vegetation and seed bank still differed significantly. The soil was persistently altered on the Gallo-Roman sites resulting in elevated phosphorus levels and pH (dependent on initial soil conditions) which translated into increased vegetation and seed bank species richness. Though spatially isolated, Gallo-Roman sites supported both a homogenized vegetation and seed bank. Vegetation differences were not the only driver behind seed bank differences. Similarity between vegetation and seed bank was low and the possibility existed that agricultural ruderals were introduced via the former land use. Ancient human occupation leaves a persistent trace on forest soil, vegetation and seed bank and appears to do so at least 1,600 years after the former occupation. The geochemical alterations created an entirely different habitat causing not only vegetation but also the seed bank to have altered and homogenized composition and characteristics. Seed bank differences likely persisted by the traditional forest management and altered forest environment.  相似文献   

Treatment with amiodarone of refractory ventricular tachycardia in a horse     

De Clercq D  van Loon G  Baert K  De Backer P  Deprez P 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2007,21(4):878-880

  相似文献   

Nutrient supply at the local tree level in mixed forests of sessile oak and beech     

Hans Nickmans  Hugues Titeux  Kris Verheyen  Quentin Ponette 《European Journal of Forest Research》2018,137(6):807-817

In mixed-species forests, tree species composition can affect nutrient return through litter fall. This in turn is expected to have an effect on soil available nutrients, which could influence the nutrient status at the local tree level. Using ion-exchange resins, we estimated resin available soil nutrients at two depths beneath target trees of sessile oak and beech in the Belgian Ardennes. First we tested whether resin available nutrients were related to tree nutrition, using foliar nutrient concentrations as a proxy. In a second step, we tested whether local litter fall, through total nutrient return or litter species composition, affected resin available nutrients. In a final stage, we tested the impacts of local stand composition, as an integrated proxy of above- and belowground processes, and compared them to those of litter composition. With the exception of P for oak, nutrient supply was only poorly related to foliar nutrient concentrations for both target species. The effects of litter fall on nutrient supply were driven by litter species composition and not by total nutrient inputs. Litter composition and local stand composition effects were in close agreement. Our results show that nutrient supply to target trees in mixed-species stands is affected by local neighbourhoods, yet to a limited extent. Direct translation of resin available nutrients into foliar concentrations is probably hampered by complex capture patterns.  相似文献   

Implementation failure of the forest expansion policy in Flanders (Northern Belgium) and the policy learning potential     

Peter Van Gossum  Liselot Ledene  Bas Arts  Rik De Vreese  Kris Verheyen 《Forest Policy and Economics》2008,10(7-8):515-522

The current study is an illustrative example of intersectoral land conflicts in a highly populated region that resulted in the non-implementation of an already agreed-upon policy. More specifically, it evaluates the implementation of the forest expansion policy in Flanders (Northern Belgium) and assesses the potential to adjust current policy. The policy implementation analysis based on the variables checklist of the new top down models points out that the forest expansion program is not successful. This is mainly due to inconsistencies within the objectives and grant schemes used in agriculture and nature conservation policy and local resistance of the agricultural sector. The Advocacy Coalition Framework was used to examine the potential to adjust current policy. For the legislative changes, no adjustments were possible because two persistent coalitions, ‘continuity-oriented’ and ‘change-oriented’, with polarized core beliefs exist. The existence of these coalitions also emerged from a Detrended Correspondence Analysis of the binary table of all questioned topics. In contrast with the legislative changes, adjustment of forest grants would be possible. Hence, only less complicated policy adjustments seem possible for the Flemish forest expansion policy, and the outlook of this policy appears bleak.  相似文献   

Gradual forest edges can mitigate edge effects on throughfall deposition if their size and shape are well considered     

Karen Wuyts  An De Schrijver  Frederic Vermeiren  Kris Verheyen 《Forest Ecology and Management》2009

For the protection and promotion of biodiversity in forest edges and interiors, forest edge management practices are put forward like the creation of gradual forest edges (i.e., edges with a gradual increase of vegetation height from open area to forest, e.g., by means of a fringe, a belt, and a mantle). In this study, we tested the mitigating effect of gradual forest edges on the atmospheric deposition of inorganic nitrogen (N) and the potentially acidifying pollutants SO₄²⁻, NO₃⁻, and NH₄⁺ (N + S). We conducted field experiments at three exposed forest edges in Flanders and the Netherlands and compared throughfall deposition at steep edges (i.e., edges with an abrupt transition from open area to forest) and at adjacent gradual edges. Along transects perpendicular to the edges, during three months in both winter and summer, throughfall deposition of Cl⁻, SO₄²⁻, NO₃⁻, and NH₄⁺ was monitored in the forest between 0 and 64 m from the edges and in the gradual edge vegetation. At the smoothest and best fitting gradual edge, the extra N + S throughfall deposition the forest received due to edge effects was lower than at the adjacent steep edge, with on average 80 and 100% in winter and summer, respectively. This was due to a halving of the depth of edge influence and an almost full reduction of the magnitude of edge influence. This decrease in throughfall deposition in the forest was not compensated by the additional throughfall deposition on the gradual edge vegetation itself, resulting in a final decrease in throughfall deposition in the forest edge by 60% in winter and 74% in summer. While this result confirms that gradual edges can mitigate edge effects on atmospheric deposition, the results of the other sites indicate the importance of size and shape of the gradual edge vegetation in mitigating edge effects on deposition: due to insufficient height (‘size’) or inadequate shape of the gradual edge vegetation, only small or insignificant decreases in throughfall deposition were observed. Hence, for mitigating edge effects on N + S and N deposition, our results support the recommendation of creating gradual edges at forests with poorly developed, abrupt edges, but it stresses the importance of a thorough consideration of the shape and size of the gradual edge vegetation in the design and management of gradual forest edges.  相似文献   

When nature takes over from man: Dead wood accumulation in previously managed oak and beech woodlands in North-western and Central Europe     

Kris Vandekerkhove  Luc De Keersmaeker  Norbert Menke  Peter Meyer  Pieter Verschelde 《Forest Ecology and Management》2009

The accumulation of dead wood and its characteristics are analysed in forests that have been withdrawn from regular silvicultural management and left unmanaged between 10 and 150 years ago. These forests are dominated by beech (Fagus sylvatica) and oak (Quercus robur and Quercus petraea) and located in the lowlands of North-western and Central Europe.  相似文献   

Diverging effects of overstorey conversion scenarios on the understorey vegetation in a former coppice-with-standards forest     

Hans Van Calster  Lander Baeten  Kris Verheyen  Luc De Keersmaeker  Stijn Dekeyser  Jules E. Rogister  Martin Hermy 《Forest Ecology and Management》2008,256(4):519-528

  相似文献   

Pseudomonas aeruginosa 7NSK2-induced Systemic Resistance in Tobacco Depends on in planta Salicylic Acid Accumulation but is not Associated with PR1a Expression   总被引：3，自引：0，他引：3  

Geert De Meyer  Kris Audenaert  Monica Höfte 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(5):513-517

Root colonization by rhizobacteria can induce a systemic resistance in plants that is phenotypically similar to systemic acquired resistance induced by a localized pathogen infection. We used the tobacco–tobacco mosaic virus model to investigate whether the systemic resistance induced by the rhizobacterium Pseudomonas aeruginosa 7NSK2 is mediated by the systemic acquired resistance signal transduction pathway. Experiments with nahG-transformed tobacco revealed that Pseudomonas aeruginosa 7NSK2-induced resistance depended on in planta salicylic acid accumulation for its expression but not for its induction and is, in this respect, similar to systemic acquired resistance. However, Pseudomonas aeruginosa 7NSK2-induced resistance was, unlike systemic acquired resistance, not associated with PR1a expression at the time of challenge with tobacco mosaic virus. This suggests that Pseudomonas aeruginosa 7NSK2 treatment would only potentiate defense gene expression in systemic tissue, which would also explain why its level of resistance is lower than in case of systemic acquired resistance. Because we demonstrated that induced resistance by Pseudomonas aeruginosa 7NSK2 exclusively depends on the production of salicylic acid by this strain our conclusions might also account for other salicylic acid-producing and resistance-inducing rhizobacteria.  相似文献   

Environmental drivers of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> abundance in forest fragments of rural European landscapes     

Steffen Ehrmann  Jaan Liira  Stefanie Gärtner  Karin Hansen  Jörg Brunet  Sara A. O. Cousins  Marc Deconchat  Guillaume Decocq  Pieter De Frenne  Pallieter De Smedt  Martin Diekmann  Emilie Gallet-Moron  Annette Kolb  Jonathan Lenoir  Jessica Lindgren  Tobias Naaf  Taavi Paal  Alicia Valdés  Kris Verheyen  Monika Wulf  Michael Scherer-Lorenzen 《BMC ecology》2017,17(1):31

  相似文献