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排序方式: 共有990条查询结果,搜索用时 734 毫秒
981.
982.
Tobias Schwarz MA Dr. Med. Vet. Federica Morandi DVM Giacomo Gnudi Dr. Med. Vet. Erik Wisner DVM Calum Paterson MSc Martin Sullivan BVMS PhD Pamela Johnston BVM&S PhD 《Veterinary radiology & ultrasound》2000,41(4):335-339
The radiographic appearance of nodular fat necrosis is described in ten cats and one dog. The most common radiographic sign was the presence of a focal mineralized circular to oval soft tissue mass in the abdominal fat as present in 9 cats. These masses had a distinct eggshell-like rim encapsulating the lesion. In one cat and one dog multiple masses were present, without radiographic signs of mineralization. Abdominal ultrasound was performed in three cats and one dog, findings included the presence of hyperechoic masses with associated acoustic shadowing, some with a hypoechoic centre. Almost all animals were old and obese. In three cats and one dog, changes were confirmed with biopsy or post mortem examination. Lesions having the appearance of those in this paper are most likely incidental findings and should not be confused with abdominal masses of neoplastic origin. Ultrasound can be helpful in identifying such lesions. 相似文献
983.
van Leeuwen Erik P. Hendriks Kees C. M. A. Klap Jaco M. de Vries Wim de Jong Erik Erisman Jan Willem 《Water, air, and soil pollution》2000,119(1-4):335-362
In order to assess the relationship betweenenvironmental stress and crown condition of foresttrees monitored since 1986 in Europe, estimates ofstress factors, including temperature stress, droughtstress and air pollution stress, were derived with thebest data, methods and models currently available.This paper presents information on the methods used toderive such stress factors, and on the overall ranges,the temporal trends, the spatial distribution and thereliability of the calculated stress factors. Thetemperature stress indices did not show much temporalvariation between 1985 to 1995. As expected spatialpatterns were north-south orientated, going fromcolder northern regions to warmer southern regions.The calculated relative transpiration showed a morecomplex pattern, coinciding to a large extend withpatterns of rainfall and temperature. Potential aciddeposition decreased between 1986 and 1992, butremained fairly constant after 1992. The strongdecrease was mainly the result of the decrease inSOx deposition, and to a small decrease inNOy deposition. Highest levels of the S and Ndeposition were calculated in Central and WesternEurope. Base cation deposition was largest in coastalareas and in southern Europe. This is mainly due tosoil dust, Sahara dust and sea salt. Base cationdeposition can compensate almost entirely for thepotential inputs in the south of Europe, whereas incentral Europe it equalled about 25% of thepotential acid input. A comparison between sitespecific modelled deposition and deposition derivedfrom throughfall data showed that the total aciddeposition is usually overestimated by the model,whereas the total nitrogen deposition isunderestimated, especially at plots with high nitrogenloads. There is, however, a significant correlationbetween measured and modelled data for all S and Ndeposition, thus allowing their use in a statistical analyses. 相似文献
984.
Jens‐Erik Dessen Turid Mrkre Jan Ivar Bildy Stig N. Johnsen Lars Thomas Poppe Bjarne Hatlen Magny S. Thomassen Kjell‐Arne Rrvik 《Journal of fish diseases》2019,42(1):21-34
This study demonstrated that increased dietary protein‐to‐lipid ratio (P/L‐ratio) improved survival of farmed Atlantic salmon naturally affected by pancreas disease (PD). In addition to diet, body weight (BW) and delousing mortality prior to the PD outbreak also contributed significantly (p < 0.05) to explain the observed variation in PD‐associated mortality. Subsequent to the PD outbreak, large amount of fish failed to grow and caused thin fish with poor condition (runts). At the end of the trial, significantly (p < 0.05) lower amounts of runt fish and increased amount of superior graded fish where detected among fish fed increased P/L‐ratio and within the fish with the largest BWs prior to PD. Diet, BW and delousing mortality contributed significantly (p < 0.05) to explain the variation in the amount of superior graded fish, whereas BW and diet explained the variation in the amount of runt fish. A significant (p < 0.01) negative linear relationship was observed between the amount of superior graded fish and the total mortality, whereas a positive linear relationship was detected between percentage of fillets with melanin and the total mortality. Thus, increased dietary P/L‐ratio seem to reduce the mortality and impaired slaughter quality associated with PD. 相似文献
985.
Paul Y. Barthez Erik R. Wisner Stephen P. DiBartola Dennis J. Chew 《Veterinary radiology & ultrasound》1999,40(6):649-656
The transit time of 99mTc-DTPA in the kidneys is an indicator of renal function that has been used in humans for the diagnosis of renal obstruction, renal artery stenosis, and rejection of renal transplants. Its use, however, has not been reported in the dog. 99mTc-DTPA scintigraphy was performed in 8 normal dogs and the time of peak was calculated as the time between the injection and the maximum renal uptake. Deconvolution analysis was performed to estimate the renal retention function using 3 different techniques, i.e. the matrix method, the fast Fourier transform (FFT) method, and the constrained least square method. The parenchymal and whole kidney mean transit times were calculated from the deconvolved renogram using alternatively the thorax and the aorta as the input function. Average mean transit times ranged from 137 to 184 seconds. Parenchymal mean transit time was significantly shorter than whole kidney mean transit time (P<0.03). Mean transit time calculated with the thorax as the input function was significantly longer than mean transit time calculated with the aorta (P<0.001). No differences were observed between mean transit time calculated with the matrix, FFT and constrained least square methods. 相似文献
986.
Polycyclic Aromatic Hydrocarbons in the Sediments of the Milwaukee Harbor Estuary, Wisconsin, U.S.A.
An Li Irwan A. Ab Razak Fan Ni Michael F. Gin Erik R. Christensen 《Water, air, and soil pollution》1998,101(1-4):417-434
From 1990 to 1994, a total of 21 sediment cores and 37 grab sediment samples were collected from the Milwaukee Harbor Estuary. Each sediment core was sectioned and dated using 210Pb and137 Cs radioisotope techniques. A total of 305 samples were analyzed for sixteen polycyclic aromatic compounds (PAHs). Grain size distribution, porosity, and total organic carbon content as measured by loss on ignition were also determined. The results provide a historical overview of the impact of industrialization in the Milwaukee area. Although highly variable, the concentration profile of PAHs show, in general, peaks in the 1950's through 1980's. The PAH concentrations have declined since then for most sediment cores. The current levels of total PAHs in most surface sediment samples range from 25 to 200 ppm. A few cores, some of which were collected in 1994, have an elevated PAH concentration at the surface. Toxicity of the surface sediments was evaluated by comparing with the benchmark values developed by the United States National Oceanic and Atmospheric Administration (NOAA). The most heavily contaminated area was found in the Kinnickinnic River between the Becher Street Bridge and the Wisconsin Wrecking Company Wharf. The highest total PAH concentration determined from seven vibra cores collected in this area ranges from 380 to 1000 ppm. The former Wisconsin Solvay Coke Company may have been a major point source of PAHs until the 1970's. Highway traffic and various industrial discharges also contribute to the sediment PAHs in this area. 相似文献
987.
Inger Hilde Zahl Anders Kiessling Ole Bent Samuelsen Rolf Erik Olsen 《Fish physiology and biochemistry》2010,36(3):719-730
Stress in response to anesthesia with benzocaine, MS-222, metomidate and isoeugenol was studied in Atlantic salmon (Salmo salar), Atlantic halibut (Hippoglossus hippoglossus), and Atlantic cod (Gadus morhua) with no concomitant stress from handling or confinement in association with anesthesia or sampling. All of the anesthetics
tested induced a stress response in all species, displayed by a release of cortisol to the water. MS-222 anesthesia elicited
the highest cortisol release rates, reaching maximum levels 0.5 h post-exposure and returning to basal levels after 3–4 h.
Benzocaine anesthesia caused a bimodal response where the initial peak in cortisol release rate was followed by a second increase
lasting towards the end of the trial (6 h). This bimodality was more profound in Atlantic salmon than in Atlantic halibut
and Atlantic cod. Metomidate anesthesia induced the lowest release of cortisol of the agents tested in both Atlantic halibut
and Atlantic cod, but resulted in a bimodal response in Atlantic salmon where the initial increase in cortisol release was
followed by a larger increase peaking at 2–2.5 h post exposure before returning to basal levels after 5 h. The stress induced
in Atlantic salmon by isoeugenol anesthesia resembled that of MS-222, but did not reach the same elevated level. Overall,
the cortisol release was most profound in Atlantic salmon followed by Atlantic halibut and Atlantic cod. 相似文献
988.
Tore S. Kristiansen Lars H. Stien Jan Erik Fosseidengen Espen Strand Jon-Erik Juell 《Aquaculture International》2011,19(4):625-636
Atlantic cod and other teleosts with closed swimbladders have slow gas resorption rates and are therefore vulnerable to sudden pressure reductions that lead to swimbladder expansion and possible loss of behavioural control. This problem is of particular relevance to fish farmers, who require safe protocols for lifting of cages containing cod that account for swimbladder expansion. To recommend a limit for pressure reduction, we experimentally determined the maximum pressure reduction, relative to neutral buoyancy pressure, free-swimming farmed cod would expose themselves to. Classical reward conditioning was used to motivate cod that were neutrally buoyant at 2?C3.3 ATM (10?C23 m depth) to respond to a sound signal by swimming rapidly upwards to a feeding station positioned at 1.5 ATM (5 m depth). Sixteen cod were implanted with data storage tags (DSTs) that registered their ambient pressure throughout the experiment. The DST data showed that cod voluntarily stopped rapid ascents before they reached the feeding station at an average maximum pressure reduction of about 41% relative to their neutral buoyancy pressure. This was equivalent to a 70% swimbladder expansion relative to neutral volume. During the experiment, cod seldom remained above their neutral buoyancy depths, except when feeding, indicating a behavioural aversion to positive buoyancy. To avoid the loss of buoyancy control in cod, we conclude that single lifting events of sea-cages, which forces swimbladder expansion, should never exceed a 70% expansion of the swimbladder above the pre-existing neutral buoyancy volume. 相似文献
989.
The continental shelf of the southeast United States forms one of North America's Large Marine Ecosystems (LME). Despite increased attention on ecosystem management, fisheries within this LME continue to be managed on a single stock basis, in part because interactions among species and environmental effects are poorly understood. Using fishery data from two different sources (recreational and commercial), we applied multivariate statistical techniques to elucidate spatial and temporal dynamics of reef fish assemblages. Spatial analyses of species composition revealed a zoogeographic boundary near Cape Canaveral, Florida, suggesting that management of reef fishes could be applied to the northern and southern regions with discrimination. Temporal analyses revealed, in general, gradual changes in species composition of landings, but with primary shifts in 1992 and again in 1999–2000. Chronological patterns, evident in these two independent data sets, bear the signature of one or more trending factors, which in this LME could include increased exploitation, spread of invasive species, habitat degradation, or climate change. 相似文献
990.
Kelvin T. Chiong Mona B. Damaj Carmen S. Padilla Carlos A. Avila Shankar R. Pant Kranthi K. Mandadi Ninfa R. Ramos Denise V. Carvalho T. Erik Mirkov 《Plant methods》2017,13(1):106