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排序方式: 共有171条查询结果,搜索用时 15 毫秒
91.
Genchi C Mortarino M Rinaldi L Cringoli G Traldi G Genchi M 《Veterinary parasitology》2011,176(4):295-299
Climatic changes, together with an increase in the movement of dogs across Europe, have caused an increase in the geographical range of Dirofilaria infections. The present paper is focuses on northeastern European countries, where survey data have shown an increase of Dirofilaria repens infections both in animals and humans. A growing degree day-based forecast model has been developed to predict the occurrence. The model is based on evidence that there is a threshold of 14 °C below which Dirofilaria development will not proceed in mosquitoes, there is a requirement of 130 growing degree-days (GDDs) for larvae to reach infectivity, and there is a maximum life expectancy of 30 days for a mosquito vector. The output of this model predicted that the summer temperatures (with peaks in August) are sufficient to facilitate extrinsic incubation of Dirofilaria even at latitudes of 56 °N and longitudes of 39 °E. Despite the fact that both Dirofilaria immitis and D. repens have the same temperature requirement for extrinsic incubation in mosquitoes, empirical data has shown that D. repens is the main cause of dirofilarial infections in both humans and animals. Clinical signs are absent in most canine infections with D. repens. Furthermore, diagnosis is problematic and in-clinic serological tests, such as those for D. immitis, do not exist. Therefore, most infections go undiagnosed, allowing the infection to spread undetected. 相似文献
92.
93.
Larval population structure of Engraulis encrasicolus in the Strait of Sicily as revealed by morphometric and genetic analysis 下载免费PDF全文
Angela Cuttitta Bernardo Patti Teresa Maggio Enza Maria Quinci Anna Maria Pappalardo Venera Ferrito Vito De Pinto Marco Torri Francesca Falco Aldo Nicosia Marianna Musco Grazia Maria Armeri Francesco Placenti Giorgio Tranchida Roberta Mifsud Angelo Bonanno Salvatore Mazzola 《Fisheries Oceanography》2015,24(2):135-149
In order to investigate the larval population structure, specimens of Engraulis encrasicolus larvae from five different locations in the Strait of Sicily were analyzed by means of otolith readings, morphometric and genetic techniques. The distribution of age in day, identified by means of the otolith readings and associated with the oceanographic parameters, was useful to identify possible spawning areas and transport dynamics. The presence of more than one spawning area suggested the possibility that two or more sub‐populations may co‐exist in the study area. The morphometric characteristics were more adequate than genetic parameters to discriminate the different larval groups. The most relevant variables for the separation were the mouth length (ML) and the body diameter (BD). The population structure by means of genetic data reported the presence of two phylogroups co‐occurring among samples in each sampling locations specimens. The pattern of genetic divergence among anchovy larvae in the Strait of Sicily was congruent with previous studies conducted on adult populations present in other Mediterranean areas with different molecular markers. The habitat‐specific nature of the morphological variation and the lack of corresponding genetic variation among larvae from the different locations suggested that the observed differences in morphology could be linked to environmental parameters. The body form differences among different larvae samples could reflect the nutritional status of larvae. In fact, these differences were found among anchovy larvae collected in areas with different oxygen and fluorescence, which is an index of primary productivity and is linked to the availability of food for anchovy larvae. 相似文献
94.
Anna Giannina Perugini Maria Rosaria Carullo Assunta Esposito Vincenzo Caligiuri Federico Capuano Giorgio Galiero Giuseppe Iovane 《Veterinary research communications》2010,34(4):387-392
In the last two decades, the emergence and spread of antimicrobial-resistant pathogens, among them Salmonella, has become
a serious health hazard worldwide, and specifically the high incidence of multidrug resistance has been encountered widely
in many European countries. This study examines the antimicrobial supsceptibility of Salmonella enterica strains Typhimurium
and Enteritidis isolated in Campania and Calabria region (Southern Italy) from animal and food of animal origin. The relationship
of antibiotic resistance phenotype and the presence of some resistance genes has been also investigated. As espected, our
results showes that resistance to ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracycline is common, although
resistance to other antibiotics (i.e.:nalidixic acid) and other resistance patterns occur. The genetic resistant patterns
have been partially described for this food-borne pathogen but efforts are needed to realize the complete characterization
of antimicrobial resistance genes. 相似文献
95.
96.
Giacomo Gnudi Antonella Volta Mattia Bonazzi Margherita Gazzola Giorgio Bertoni 《Veterinary radiology & ultrasound》2005,46(5):423-426
The aim of this study was to describe the ultrasonographic features of grass awns in soft tissue. A 10 MHz linear transducer was used. Ultrasound images from 25 dogs (27 awns) were collected and compared with the results from water bath studies using wild oat seeds (Avena spp.) collected in the field. Wild oat seeds were the most common grass awn found in soft tissue of dogs. Ultrasonographically grass awns appeared as a double/triple spindle-shaped echogenic interface within soft tissue. The same appearance was observed in water bath studies. In four dogs, the grass awn was removed surgically with a clamp introduced into a fistulous tract, using sonographic guidance. The grass awn was not found surgically in only three dogs, suggesting more attention during surgery. Ultrasonography is a useful diagnostic imaging technique to identify grass awns within soft tissue. 相似文献
97.
Daniele Castagneri Emanuele Lingua Giorgio Vacchiano Paola Nola Renzo Motta 《Annals of Forest Science》2010,67(3):304-304
98.
99.
Rupert Seidl Chris S. Eastaugh Koen Kramer Michael Maroschek Christopher Reyer Jarosław Socha Giorgio Vacchiano Tzvetan Zlatanov Hubert Hasenauer 《European Journal of Forest Research》2013,132(5-6):653-666
Scaling is widely recognized as a central issue in ecology. The associated cross-scale interactions and process transmutations make scaling (i.e. a change in spatial or temporal grain and extent) an important issue in understanding ecosystem structure and functioning. Moreover, current concepts of ecosystem stewardship, such as sustainability and resilience, are inherently scale-dependent. The importance of scale and scaling in the context of forest management is likely to further increase in the future because of the growing relevance of ecosystem services beyond timber production. As a result, a consideration of processes both below (e.g. leaf-level carbon uptake in the context of climate change mitigation) and above (e.g. managing for biodiversity conservation at the landscape scale) the traditional focus on the stand level is required in forest ecosystem management. Furthermore, climate change will affect a variety of ecosystem processes across scales, ranging from photosynthesis (tree organs) to disturbance regimes (landscape scale). Assessing potential climate change impacts on ecosystem services thus requires a multi-scale perspective. However, scaling issues have received comparatively little attention in the forest management community to date. Our objectives here are thus first, to synthesize scaling issues relevant to forest management and second, to elucidate ways of dealing with complex scaling problems by highlighting examples of how they can be addressed with ecosystem models. We have focused on three current management issues of particular importance in European forestry: (1) climate change mitigation through carbon sequestration, (2) multi-functional stand management for biodiversity and non-timber goods and services and (3) improving the resilience to natural disturbances. We conclude that taking into account the full spatiotemporal heterogeneity and dynamics of forest ecosystems in management decision-making is likely to make management more robust to increasing environmental and societal pressures. Models can aid this process through explicitly accounting for system dynamics and changing conditions, operationally addressing the complexity of cross-scale interactions and emerging properties. Our synthesis indicates that increased attention to scaling issues can help forest managers to integrate traditional management objectives with emerging concerns for ecosystem services and therefore deserves more attention in forestry. 相似文献
100.
Francesco Giammarchi Giorgio Vacchiano Andrea Bertagnolli Maurizio Ventura Pietro Panzacchi Paolo Cherubini 《Scandinavian Journal of Forest Research》2017,32(2):142-153
Knowledge about the stand structure and dynamics of subalpine forests is crucial to preserve their multifunctionality. In the present study, we reconstructed the spatiotemporal dynamics of a subalpine Pinus cembra forest in the eastern Italian Alps in response to natural disturbances and forest management. We adopted a concurrent point pattern, dendroecological and growth dominance (GD) analysis. We mapped and measured all trees of Pinus cembra and Larix decidua in a 1?ha plot. We analyzed intra- and interspecific spatial patterns and spatial autocorrelation of tree size and age. We explored establishment dynamics and shifts in competition by analyzing growth suppression/release patterns and GD trends. Results showed a clumped, uneven-aged, multilayered structure where pine was dominant. The synergic action of ecological and human-induced factors is discussed to explain the prevalence of pine over time. Spatial pattern and autocorrelation analyses suggest a different colonization strategy of the two species, in which pine established after small-scale perturbations and experienced a stronger inter- and intra-specific competition. The interruption of tree establishment and shift in GD toward large trees resulting from the lack of forest management are the most important findings of this research. This highlights the importance of an active management to avoid the homogenization of the forest structure that is generally associated with a reduction in biodiversity and protective ability of forests. 相似文献