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排序方式: 共有711条查询结果,搜索用时 15 毫秒
1.
2.
David Lipsitz DVM Robin E. Levitski DVM Wayne L. Berry BVSc MMedVet 《Veterinary radiology & ultrasound》2001,42(1):14-19
Three dogs with multilobular osteochondrosarcoma of the skull were evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2, proton weighted and post contrast T1W images were obtained with a 1.5 Tesla magnet. The MR imaging findings were similar in all three dogs with mixed signal intensities in the T1W, T2W and proton weighted images and fairly large areas of contrast enhancement in the post contrast T1W images. The extent of brain and soft tissue involvement were well delineated and provided useful information concerning surgical planning. MR imaging provided a useful method of evaluating dogs with skull tumors. 相似文献
3.
Jacqueline W.M. Postma Pål Axel Olsson Ursula Falkengren-Grerup 《Soil biology & biochemistry》2007,39(2):400-408
Colonisation by root endophytes can be beneficial to plants growing on acid, nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi can supply herbs with nutrients and may give protection against aluminium toxicity. Two other root colonising fungi, fine endophytes (FE) and dark septate fungi (DSE), are less well known but are potentially of benefit to their host plant. AM fungi are the most prevalent symbionts in herbs at neutral to acidic soil pH. At extremely low pH, fungal growth can be limited and AM colonisation is usually rare. Fine and dark septate endophytes, on the other hand, have been observed more often under these conditions. In order to relate endophyte colonisation to a gradient in soil pH, we investigated root colonisation by AM, FE and DSE in Maianthemum bifolium, Galium odoratum, Mercurialis perennis and Stellaria nemorum, from a range of acidic beech forests. With decreasing pH, colonisation by AM decreased, whereas the other two endophytes increased. AM and FE colonisation were inversely correlated in Maianthemum bifolium. We compared changes in root colonisation with those in chemical composition of soil and leaf samples and found a positive correlation between leaf magnesium concentrations and the presence of DSE in Galium odoratum. Aluminium concentration in Maianthemum bifolium tended to be lower when FE colonisation was high, suggesting a possible role for the fungi in plant protection against Al. We suggest that FE and DSE may replace AM fungi in herbaceous vegetation at extremely low pH, counteracting some of the negative effects of high soil acidity on plants. 相似文献
4.
Frequency of pulmonary mineralization and hypoxemia in 21 dogs with pituitary-dependent hyperadrenocorticism 总被引:1,自引:0,他引:1
Berry CR Hawkins EC Hurley KJ Monce K 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2000,14(2):151-156
The purpose of this study was to determine the frequency of hypoxemia and pulmonary mineralization using 99m Tc-methylene diphosphonate (99m Tc-MDP) in dogs with pituitary-dependent hyperadrenocorticism (PDH). Twenty-one dogs with PDH were pro-spectively evaluated using thoracic radiography, arterial blood gas analysis, and bone phase and pulmonary perfusion scintigraphy (using 99m Tc-macro-aggregated albumin [99m Tc-MAA]). The radiographs and bone and perfusion studies were evaluated subjectively. An averaged quantitative count density ratio was calculated between the thorax and cranial thoraco-lumbar vertebrae from lateral thoracic 99m Tc-MDP images. Thoracic: vertebral ratios were calculated using 99m Tc-MDP studies from 21 control dogs. The thoracic: vertebral ratios were compared between the 2 groups (PDH and control). The mean age (±SD) of the 21 PDH dogs was 10.2 (±3) years, whereas the mean age of the control group was 9.8 (±3) years. Seven of the 21 dogs with PDH were hypoxemic (denned as an arterial partial pressure of oxygen [PaO2 ] <80 mm Hg) with an average PaO2 (±SD) of 62 (±15) mm Hg. Of the 7 hypoxemic dogs, 2 were found to have pulmonary mineralization based on bone scintigraphic images. Pulmonary perfusion abnormalities were not identified using 99m Tc-MAA in any of the 21 PDH dogs. Six PDH dogs had an abnormal interstitial pulmonary pattern and 5 of these dogs were hypoxemic. The average quantitative thoracic: vertebral ratio was not significantly different between the PDH and control dogs (0.5 ± 0.4 versus 0.4 ± 0.1, P = .16). Causes of hypoxemia other than pulmonary thromboembolism should be considered in dogs with PDH. Pulmonary mineralization may contribute to hypoxemia in dogs with PDH. 相似文献
5.
Smarick SD Rylander H Burkitt JM Scott NE Woelz JS Jandrey KE Aldrich J Sturges BK 《Journal of the American Veterinary Medical Association》2007,230(3):370-374
CASE DESCRIPTION: A 9-year-old dog was evaluated for traumatic cervical myelopathy after a surgical attempt to realign and stabilize the C2 and C3 vertebrae. CLINICAL FINDINGS: The dog could not ventilate spontaneously and was tetraplegic; positive-pressure ventilation (PPV) was maintained. Myelography and computed tomography revealed spinal cord compression with subluxation of the C2 and C3 vertebrae and extrusion of the C2-3 intervertebral disk. TREATMENT AND OUTCOME: Surgically, the protruding disk material was removed and the vertebrae were realigned with screws and wire. For PPV, assist control ventilation in volume control mode and then in pressure control mode was used in the first 6 days; this was followed by synchronized intermittent mandatory ventilation until 33 days after the injury; then only continuous positive airway pressure was provided until the dog could breathe unassisted, 37 days after the injury. Physical therapy that included passive range of motion exercises, neuromuscular electrical stimulation, and functional weight-bearing positions was administered until the dog was discharged 46 days after injury; the dog was severely ataxic and tetraparetic but could walk. Therapy was continued at home, and 1 year later, the dog could run and had moderate ataxia and tetraparesis. CLINICAL RELEVANCE: Hypoventilation with tetraparesis in traumatic spinal cord injury can be successfully treated with PPV exceeding 30 days, surgery, and physical therapy. 相似文献
6.
Per McCord Vanessa Gordon Gopesh Saha Jacqueline Hellinga George Vandemark Richard Larsen Mark Smith David Miller 《Euphytica》2014,200(2):269-279
Alfalfa (Medicago sativa L.) is an internationally significant forage crop. Forage yield, lodging resistance and spring vigor are important agronomic traits conditioned by quantitative genetic and environmental effects. The objective of this study was to identify quantitative trait loci (QTL) and molecular markers associated with increased forage yield, resistance to lodging, and spring vigor. A backcross population composed of 128 progeny was developed by crossing the breeding parents DW000577 (lodging susceptible) and NL002724 (lodging-resistant) and back-crossing an individual F1 plant to the maternal parent (i.e. DW000577). A linkage map of NL002724 was developed based upon the segregation of 236 AFLP, SRAP, and SSR markers among the backcross progeny. The markers were distributed among 14 linkage groups, covering an estimated recombination distance of 1497.6 centiMorgans (cM). Replicated clones of both parents and backcross progeny were evaluated in the field for estimated forage yield, lodging, and spring vigor in Washington and Wisconsin during 2007 and 2008. Significant QTL were found for all three traits. In particular, two QTL for lodging resistance were identified that explained ≥14 % of trait variation, and were significant in all years and locations. Major QTL explaining over 25 % of trait variation for forage yield were detected in multiple environments at two separate locations on chromosome III. Several QTL for spring vigor were located in the same or similar positions as QTL for forage yield, possibly explaining the significant correlation between these traits. Molecular markers associated with the aforementioned QTL were also identified. 相似文献
7.
A phase transition from a classical thermal mixed state to a quantum-mechanical pure state of exciton polaritons is observed in a GaAs multiple quantum-well microcavity from the decrease of the second-order coherence function. Supporting evidence is obtained from the observation of a nonlinear threshold behavior in the pump-intensity dependence of the emission, a polariton-like dispersion relation above threshold, and a decrease of the relaxation time into the lower polariton state. The condensation of microcavity exciton polaritons is confirmed. 相似文献
8.
Hans G.P. Jansen Angel Rodriguez Amy Damon John Pender Jacqueline Chenier Rob Schipper 《Agricultural Systems》2006
Based on the results of participatory diagnostic surveys conducted in 95 rural communities in the hillsides of Honduras, we determine income earning strategies at the community level; identify their main determinants; and analyze the adoption of of conservation practices. Eight income-earning strategies were distinguished that reflect differences in comparative advantage between communities. We explain the choice of income earning strategy using a multinomial logit model that includes biophysical, economic, social and institutional variables. We use a probit model to show that adoption of conservation practices is determined by the type of income earning strategy, population density, market access, and organizational variables. 相似文献
9.
Jennifer A Berry Lewis J Bartlett Selina Bruckner Christian Baker S Kris Braman Keith S Delaplane Geoffrey R Williams 《Journal of insect science (Online)》2022,22(1)
The American beekeeping industry continually experiences colony mortality with annual losses as high as 43%. A leading cause of this is the exotic, ectoparasitic mite, Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae). Integrated Pest Management (IPM) options are used to keep mite populations from reaching lethal levels, however, due to resistance and/or the lack of suitable treatment options, novel controls for reducing mites are warranted. Oxalic acid for controlling V. destructor has become a popular treatment regimen among commercial and backyard beekeepers. Applying vaporized oxalic acid inside a honey bee hive is a legal application method in the U.S., and results in the death of exposed mites. However, if mites are in the reproductive stage and therefore under the protective wax capping, oxalic acid is ineffective. One popular method of applying oxalic is vaporizing multiple times over several weeks to try and circumvent the problem of mites hiding in brood cells. By comparing against control colonies, we tested oxalic acid vaporization in colonies treated with seven applications separated by 5 d (35 d total). We tested in apiaries in Georgia and Alabama during 2019 and 2020, totaling 99 colonies. We found that adult honey bees Linnaeus (Hymenoptera: Apidae), and developing brood experienced no adverse impacts from the oxalic vaporization regime. However, we did not find evidence that frequent periodic application of oxalic during brood-rearing periods is capable of bringing V. destructor populations below treatment thresholds. 相似文献
10.
The potential of mini-ridging for controlling intrarow weeds: estimating minimum lethal burial depth
Charles N. Merfield Jacquelyn R. Bennett Nadine A. Berry Arthur Bluon Dean M. O’Connell Simon Hodge 《Weed Research》2020,60(5):353-362
Weed management using synthetic herbicides is undergoing a global decline, necessitating a re-evaluation of existing control measures and the development of novel weed management tools. ‘Mini-ridging’ is a non-discriminatory, physical weeding method that functions by burying weeds in the intrarow with a laterally shifted ridge of soil. In glasshouse trials using potted plants, we found that plant recovery after soil application was influenced by plant size, which in turn was influenced by plant species, developmental stage and/or age. The likelihood of plant recovery after soil application was negatively related to the depth of soil applied: very few plants survived total coverage by soil but, conversely, survival could be substantial if some parts of the plants were not covered. The results suggest that burial under a depth of 6 cm of soil would eliminate most plants regardless of species or growth stage. Larger plants would require the application of a greater total depth of soil to achieve this 6 cm of soil cover, and weed management would, therefore, tend to be more successful and more practical if weeds were targeted when still small. This research demonstrates the potential of plant burial as a simple and reliable means of non-chemical weed management, and re-emphasises that, for weed control to be effective, the applied soil layer must cover the whole plant. 相似文献