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991.
A J Nixon R M Adams M B Teigland 《Journal of the American Veterinary Medical Association》1988,192(3):360-362
Bilateral subchondral cystic lesions of the femoral head in a horse resulted in lameness. The lesions had resulted in degenerative disease in the left coxofemoral joint. The cause of lameness was confirmed by use of intra-articular anesthesia, joint fluid analysis, and radiography. Subchondral cystic lesions involving the femoral head should be considered in the differential diagnosis of equine lameness localized in the upper portion of the hind limb. 相似文献
992.
Although the immune response to Brucella abortus is multifaceted, the key event in contending with this pathogen appears to be the interaction of the organism with cells of the mononuclear phagocyte system. A cell culture system was developed which allowed the long-term maintenance of blood monocyte-derived macrophages in Teflon culture vessels in a relatively unstimulated state. The assay system was optimized for timing of bacteria-macrophage interaction and numbers of bacteria and macrophages used in each assay. Interaction of B. abortus strain 2308 with bovine mononuclear phagocytes from animals phenotypically resistant and susceptible to infection with B. abortus was investigated. This cell culture and assay system should provide a useful model for the investigation of intracellular parasitism in cattle. 相似文献
993.
T. Mark Neer Joe N. Kornegay 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1995,9(2):100-104
Two Labrador Retriever dogs from a common dam had similar neurological deficits consisting of cortical blindness, dullness, and loss of previously learned habits. Both were examined at 5 months of age, and histopathological examination revealed leucoencephalomalacia and vacuolar degeneration of the cerebral white matter. Histopathologic findings in these 2 dogs differed from those reported previously in Labrador Retrievers with spongy degeneration of central nervous system white matter. A nonlittermate full sibling to 1 of these dogs was examined at 1.5 years of age for similar clinical signs that did not progress for the next 25 months. 相似文献
994.
995.
Xuan Guo Nicholas C. Coops Sarah E. Gergel Christopher W. Bater Scott E. Nielsen J. John Stadt Mark Drever 《Landscape Ecology》2018,33(3):491-511
Context
The application of regional-level airborne lidar (light detection and ranging) data to characterize habitat patches and model habitat connectivity over large landscapes has not been well explored. Maintaining a connected network of habitat in the presence of anthropogenic disturbances is essential for regional-level conservation planning and the maintenance of biodiversity values.Objectives
We quantified variation in connectivity following simulated changes in land cover and contrasted outcomes when different conservation priorities were emphasized.Methods
First, we defined habitat patches using vegetation structural attributes identified via lidar. Second, habitat networks were constructed for different forest types and assessed using network connectivity metrics. And finally, land cover change scenarios were simulated using a series of habitat patch removals, representing the impact of implementing different spatial prioritization schemes.Results
Networks for different forest structure types produced very different patch distributions. Conservation scenarios based on different schemes led to contrasting changes during land cover change simulations: the scheme prioritizing only habitat area resulted in immediate near-term losses in connectivity, whereas the scheme considering both habitat area and their spatial configurations maintained the overall connectivity most effectively. Adding climate constraints did not diminish or improve overall connectivity.Conclusions
Both habitat area and habitat configuration should be considered in dynamic modeling of habitat connectivity under changing landscapes. This research provides a framework for integrating forest structure and cover attributes obtained from remote sensing data into network connectivity modeling, and may serve as a prototype for multi-criteria forest management and conservation planning.996.
Alison B. Adams Jennifer Pontius Gillian L. Galford Scott C. Merrill David Gudex-Cross 《Landscape Ecology》2018,33(4):641-658
Purpose
Accurately assessing forest carbon storage on a landscape scale is critical to understanding global carbon cycles and the effects of land cover changes on ecological processes. Calculations of regional-scale forest carbon storage that rely on maps of land cover typically reflect only coarse forest classes. How differences in carbon stored by different tree species may affect such assessments is largely unexplored. We examined a range of forest carbon storage models to understand the effects of forest type specificity on carbon storage estimates in the northeastern United States.Methods
Models estimated forest carbon in total aboveground and coarse root biomass based on three levels of forest classification specificity: (1) relative basal area by species, (2) species associations, and (3) broad forest types per IPCC (in: IPCC guidelines for national greenhouse gas inventories, IPCC, Japan, 2006) guidelines.Results
The specificity of forest type classifications influenced results with generally lower carbon storage estimates resulting from higher-specificity forest classifications. The two most specific models, with mean carbon storage estimates of 103–107 Mg/ha, were most accurate compared to field validation points. These estimates are greater than 2013 field-based U.S. Forest Service estimates (84–90 Mg/ha).Conclusions
There are many sources of uncertainty in landscape-scale carbon storage assessments. Here we show that improving detail in one of these sources, forest stand composition, increases the accuracy of these assessments, and better reflects carbon storage patterns across heterogeneous landscapes. While more work is needed, particularly to improve stand age maps, this information can inform the interpretation of current carbon storage estimates and improve future estimates in heterogeneous forests.997.
Blake A. Barbaree Matthew E. Reiter Catherine M. Hickey Nathan K. Elliott Danica Schaffer-Smith Mark D. Reynolds Gary W. Page 《Landscape Ecology》2018,33(5):829-844
Context
Animal movements are inherently linked to landscape structure. Understanding this relationship for highly-mobile species requires documenting their responses to spatiotemporal variability of resources. To that end, characterizing movement behaviors and resource distributions using the principles of habitat connectivity facilitates coordinated landscape planning efforts within highly modified landscapes.Objectives and methods
We tracked locations and movements for 156 dunlin (Calidris alpina) and 109 long-billed dowitchers (Limnodromus scolopaceus) overwintering in two regions with distinct water distributions in California’s Central Valley. We then compared residency rates, functional connectivity to other regions, and associations between movement distances and average habitat availability and structural connectivity of habitat at multiple temporal and spatial scales.Results
A widespread yet highly variable regional water distribution was associated with lower residency rates and substantially higher functional connectivity to nearby regions when compared to a stable regional water distribution characterized by a large, contiguous wetland complex. Longer movements were associated with decreasing average availability and spatial aggregation of surface water. Movement models suggested shorebirds primarily responded to habitat availability at smaller scales (<?10 km) and structural connectivity at larger scales (≥?10 km).Conclusions
Differences in movement behaviors suggested that wintering shorebirds will avoid long distance movements and remain resident within a wetland region when possible. Conservation and management efforts should reliably flood individual wetlands and agricultural lands from November to April and prioritize locations that maximize structural wetland connectivity and limit spatiotemporal variability of surface water throughout the Central Valley.998.
999.
Ryan S. Bailey Julie D. Sheldon Matthew C. Allender Mark G. Papich Sathya K. Chinnadurai 《Journal of veterinary pharmacology and therapeutics》2019,42(4):380-384
This study documents the pharmacokinetics of oral tramadol in Muscovy ducks. Six ducks received a single 30 mg/kg dose of tramadol, orally by stomach tube, with blood collection prior to and up to 24 hr after tramadol administration. Plasma tramadol, and metabolites O‐desmethyltramadol (M1), and N,O‐didesmethyltramadol (M5) concentrations were determined by high‐pressure liquid chromatography (HPLC) with fluorescence (FL) detection. Pharmacokinetic parameters were calculated using a one‐compartment model with first‐order input. No adverse effects were noted after oral administration. All ducks achieved plasma concentrations of tramadol above 0.10 μg/ml and maintained those concentrations for at least 12 hr. Elimination half‐life was 3.95 hr for tramadol in ducks, which is similar to other avian species. All ducks in this study produced the M1 metabolite and maintained plasma concentrations above 0.1 μg/ml for at least 24 hr. 相似文献
1000.