Neuroscience. Overcoming inhibitions     

Kim WY  Snider WD 《Science (New York, N.Y.)》2008,322(5903):869-872

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黄土耕作坡面溅蚀过程中微地形响应特征   总被引：4，自引：0，他引：4  

塔娜  王健  张慧荟  田龙  张青峰 《水土保持通报》2016,36(1):110-114

[目的]探究60mm/h雨强下不同耕作坡面在溅蚀阶段的微地形变化特征,为黄土坡地水土保持耕作方式布设提供科学依据。[方法]在室内人工模拟降雨试验的基础上,采用激光扫描量测方法分别获取溅蚀前后4种不同耕作方式(人工锄耕、人工掏挖、等高耕作、耙磨整平)黄土坡面微地形相对高程,并对能反映微地形变化的高精度M-ΔDEM进行了分析。[结果]不同耕作措施下坡面微地形均具有较弱的空间变异,其空间分异主要受耕作措施的影响;降雨对微地形具有一定的夷平效应,且不同耕作坡面在1~1.3m尺度范围内均表现出侵蚀平衡现象;不同耕作微地形对溅蚀均具有阻滞作用,其中人工掏挖和等高耕作具有较强的水土保持作用。[结论]微地形水系分维能较好地反映复杂的微地形特征,而坡面耕作方式是溅蚀过程中微地形时空变异分布状况的控制性因子。  相似文献   

Lymphoreticular alterations in neonatally thymectomized and antilymphocyte globulin treated Holstein-Friesian calves     

T.G. Snider  K.R. Pierce 《Veterinary immunology and immunopathology》1981,2(4):331-342

Neonatal calves were thymectomized when 4 to 10 days old and treated briefly with antilymphocyte globulin. Non-thymectomized calves were treated with normal horse globulin or not treated with antilymphocyte globulin. The lymph nodes were examined at selected times by light microscopy and immunofluorescence and after necropsy.The prescapular lymph nodes at 5 weeks represented normal, normally reactive and abnormally reactive structure. Peripheral lymph nodes from 5-week-old calves not treated by thymectomy or antilymphocyte globulin had a low level of lymphopoietic activity. The thymus intact calves treated with normal horse globulin had reactive lymphoid hyperplasia primarily of the cortex. The thymectomized, antilymphocyte globulin treated calves at this age had increased primary follicle activity and depletion of paracortical areas in peripheral lymph nodes. The degree of lymphoid hyperplasia corresponded to the relative frequency of cells with surface immunoglobulin at 5 weeks of age.The lymph nodes and spleen collected at necropsy at 16 to 26 weeks did not segregate into three distinct categories, probably a reflection of the additional stimulation on the immune system by experimental and natural antigen exposure. The differences between treatments were not observed at the time of necropsy. These morphological observations strongly support the conclusion that the calves were affected by neonatal thymectomy, but had recovered from the effect of thymectomy by 16 to 26 weeks of age.  相似文献   

Anthelmintic efficacy of fenbendazole against the bovine hookworm Bunostomum phlebotomum     

J C Williams  B A Baumann  T J Hoerner  J W Knox  T G Snider  V M Fredotovich 《American journal of veterinary research》1983,44(9):1644-1647

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Cardiac arrhythmias associated with multiple trauma in dogs     

D K Macintire  T G Snider 《Journal of the American Veterinary Medical Association》1984,184(5):541-545

Premature ventricular contractions and ventricular tachycardia were detected in 10 dogs 1 to 48 hours after trauma. All dogs were treated aggressively if the arrhythmias became severe. One dog died, 8 were discharged with stable cardiac rhythm, and 1 was euthanatized. Necropsy revealed gross and microscopic lesions of acute myocardial necrosis, probably of ischemic origin. Cardiac arrhythmias were associated with thoracic trauma, neurologic injury, severe shock, and/or extensive tissue trauma.  相似文献   

Multiple organ metastasis of an aortic body tumor in a boxer     

J M Gliatto  M A Crawford  T G Snider  R Pechman 《Journal of the American Veterinary Medical Association》1987,191(9):1110-1112

A 9-year-old sexually intact male Boxer with a history of multiple episodes of syncope and various cardiac arrhythmias was determined radiographically to have a large mass in the heart-base region and was subsequently euthanatized upon worsening of clinical signs. Histologic and ultrastructural examination of tissue from the heart-base mass indicated that the tumor was most likely a chemodectoma derived from the aortic body (aortic body tumor, extra-adrenal paraganglioma). Macroscopic and/or microscopic evidence of metastasis of the tumor was seen in the lungs, myocardium, spleen, liver, kidneys, and dura mater over the cerebellum.  相似文献   

Efficacy of fenbendazole against inhibited larvae of Ostertagia ostertagi in yearling cattle     

J C Williams  J W Knox  K S Marbury  M D Kimball  S W Scheide  T G Snider  M U David 《American journal of veterinary research》1984,45(10):1989-1993

Efficacy of fenbendazole, at doses of 7.5 and 10.0 mg/kg of body weight, against inhibited early 4th-stage larvae of Ostertagia ostertagi and other nematodes of the abomasum and intestinal tract, was investigated in naturally infected yearling heifers in late May 1982. In Louisiana, this is near the end of the period (March to May) in which maximal numbers of inhibition-prone larvae are acquired. The mean numbers of O ostertagi in 10 untreated control cattle were: adults, 4,880; developing 4th-stage larvae, 12,546; and inhibited early 4th-stage larvae, 167,931. At the 7.5 mg/kg dose level (10% liquid suspension) in 10 cattle, percentage reduction of O ostertagi in comparison with controls was: adults, 95.7%; developing 4th stages, 91.1%; and inhibited 4th stage, 55.0%. Percentage reductions of other genera were as follows: abomasum--Trichostrongylus axei, 99.6%; Haemonchus sp, 95.1%; intestinal tract--Cooperia spp, 97.8%; Trichostrongylus colubriformis, 100.0%; and Oesophagostomum radiatum 4th stage and adults, 100.0%. At the 10.0 mg/kg dose (10% liquid suspension) in 11 cattle, the percentage reduction of O ostertagi in comparison with controls was: adults, 98.6%; developing 4th stages, 92.9%; and inhibited 4th stage, 80.0%. Percentage reductions of other genera were: abomasum--T axei, 99.9%; Haemonchus sp, 98.8%; intestinal tract--Cooperia spp, 99.3%; T colubriformis, 100.0%; and Oes radiatum 4th stage and adults, 100.0%. Variability of efficacy against inhibited larvae was observed, particularly at the 7.5 mg/kg dose; at this dose, 7 of the 10 heifers in the group yielded in excess of 54,000 surviving larvae.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Disseminated protothecosis diagnosed by evaluation of CSF in a dog     

Lane LV  Meinkoth JH  Brunker J  Smith SK  Snider TA  Thomas J  Bradway D  Love BC 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2012,41(1):147-152

A 5-year-old female spayed Shetland Sheepdog Mix dog was evaluated for a history of recent seizure activity, progressive hind limb ataxia, polyuria, and polydipsia and no history of gastrointestinal signs. Physical examination findings included conscious proprioceptive deficits, ataxia, and anterior uveitis along with a hypermature cataract in the right eye. Results of a CBC, serum biochemical profile, urinalysis, and computed tomography scan of the brain were unremarkable. Cerebrospinal fluid (CSF) analysis revealed marked eosinophilic pleocytosis and rare organisms consistent with Prototheca spp within neutrophils and macrophages. On postmortem histologic examination, mononuclear inflammation and numerous intralesional algal organisms, similar to those seen on the cytologic preparation of CSF, were found in the brain, eyes, kidneys, and heart. Abnormalities were not detected on gross and histologic examination of the gastrointestinal tract. Cultures of CSF and subdural/olfactory bulb, but not intestinal tract, yielded growth of Prototheca spp, and PCR analysis and DNA sequencing confirmed the organism as Prototheca zopfii genotype 2. We have reported a rare case of disseminated protothecosis that was diagnosed by evaluation of CSF in a dog presented with neurologic signs and no overt enteric disease. Protothecosis should be considered as a rare cause of seizures, even in the absence of obvious enteric signs, and should be included in the differential diagnosis of eosinophilic pleocytosis.  相似文献   

Pine Straw Harvesting Effects on Vadose-Zone Water Content of a Leadvale Silt Loam in Western Arkansas     

Daniel H. Pote  David M. Burner  John L. Snider 《Journal of Sustainable Forestry》2013,32(3):230-238

This study addresses concerns that harvesting marketable pine straw from forests may decrease timber productivity by allowing water to evaporate more quickly from the soil surface. Three harvesting schedules and a control treatment (no straw harvest) were replicated six times on 24 plots (0.18 ha each), and compared to determine harvesting effects on water content of the soil vadose zone in an established (16 yr) loblolly (Pinus taeda L.) plantation (3.0?×?1.5 m² tree spacing). Pine straw harvesting tended to decrease volumetric soil water content (%) at depths below 20 cm, but the effect was significant (p < .05) only at the 50-cm depth in Weeks 3 and 4 (late June) of the study, when water content at this depth averaged 20.9% for soils where straw was harvested annually, and 30.2% for soils where the straw was never harvested (control). In soils where pine straw had been allowed to accumulate for at least a year after the previous harvest, average water content was not significantly different than in the control plots. Therefore, pine straw harvesting can potentially lengthen drought-stress periods for loblolly pine on some soils during the 1st yr after pine straw has been removed.  相似文献   

Electron Transport Through Photosystem II Is Not Limited By A Wide Range of Water Deficit Conditions In Field‐Grown Gossypium hirsutum     

J. L. Snider  G. D. Collins  J. Whitaker  C. D. Perry  D. R. Chastain 《Journal of Agronomy and Crop Science》2014,200(1):77-82

Despite exhaustive literature describing drought stress effects on photosynthesis in Gossypium hirsutum, the sensitivity of photosynthetic electron flow to water deficit is heavily debated. To address this, G. hirsutum plants were grown at a field site near Camilla, GA under contrasting irrigation regimes, and pre‐dawn water potential (Ψ_PD), stomatal conductance (g_s), net photosynthesis (P_N), actual quantum yield of photosystem II (Φ_PSII) and electron transport rate (ETR) were measured at multiple times during the 2012 growing season. Ψ_PD values ranged from ?0.3 to ?1.1 MPa. Stomatal conductance exhibited a strong (r² = 0.697), sigmoidal response to Ψ_PD, where g_s was ≤0.1 mol m^?2 s^?1 at Ψ_PD values ≤ ?0.86 MPa. Neither Φ_PSII (r² = 0.015) nor ETR (r² = 0.010) was affected by Ψ_PD, despite exceptionally low Ψ_PD values (?1.1 MPa) causing a 71.7 % decline in P_N relative to values predicted for well‐watered G. hirsutum leaves at Ψ_PD = ?0.3 MPa. Further, P_N was strongly influenced by g_s, whereas ETR and Φ_PSII were not. We conclude that photosynthetic electron flow through photosystem II is insensitive to water deficit in field‐grown G. hirsutum.  相似文献