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排序方式: 共有135条查询结果,搜索用时 625 毫秒
61.
62.
Blumenschine RJ Peters CR Masao FT Clarke RJ Deino AL Hay RL Swisher CC Stanistreet IG Ashley GM McHenry LJ Sikes NE Van Der Merwe NJ Tactikos JC Cushing AE Deocampo DM Njau JK Ebert JI 《Science (New York, N.Y.)》2003,299(5610):1217-1221
Excavation in the previously little-explored western portion of Olduvai Gorge indicates that hominid land use of the eastern paleobasin extended at least episodically to the west. Finds included a dentally complete Homo maxilla (OH 65) with lower face, Oldowan stone artifacts, and butchery-marked bones dated to be between 1.84 and 1.79 million years old. The hominid shows strong affinities to the KNM ER 1470 cranium from Kenya (Homo rudolfensis), a morphotype previously unrecognized at Olduvai. ER 1470 and OH 65 can be accommodated in the H. habilis holotype, casting doubt on H. rudolfensis as a biologically valid taxon. 相似文献
63.
64.
S. J. Pethybridge S. J. Jones R. G. Shivas F. S. Hay C. R. Wilson T. Groom 《Plant pathology》2008,57(6):1058-1065
The isolation frequency of Microsphaeropsis sp. in spring in association with necrotic lesions on leaves in Tasmanian pyrethrum (Tanacetum cinerariifolium) fields has increased substantially since first identification in 2001. Examination of morphological features and sequencing of the internal transcribed spacer region (ITS) resulted in the identification of a new species, herein described as Microsphaeropsis tanaceti sp. nov. The pathogenicity of three M. tanaceti isolates to two pyrethrum cultivars was confirmed by inoculating glasshouse‐grown plants in three experiments. No significant differences in the susceptibility of the two cultivars to infection by M. tanaceti were found. Symptoms were tan‐coloured spots which coalesced around the margins of the leaves. Therefore, the name ‘tan spot’ is proposed for this new disease of pyrethrum. The sensitivity of seven M. tanaceti isolates to difenoconazole and azoxystrobin, commonly used fungicides for the management of foliar diseases in spring, was assessed under in vitro conditions. Sensitivity testing for difenoconazole was conducted using a mycelial growth assay on potato dextrose agar, whilst testing for sensitivity to azoxystrobin used a conidial germination assay on water agar. Microsphaeropsis tanaceti was found to be more sensitive to azoxystrobin than difenoconazole, with complete inhibition of conidial germination at concentrations above 0·625 µg a.i. mL?1. By comparison, concentrations of 50 µg a.i. difenoconazole mL?1 or greater were required for significant inhibition of mycelial growth. It therefore appears likely that there is currently some control of tan spot as a result of the use of azoxystrobin and to a lesser extent, difenoconazole, for the control of other diseases. 相似文献
65.
Symbiotic marine bacteria chemically defend crustacean embryos from a pathogenic fungus 总被引:21,自引:0,他引:21
Embryos of the shrimp Palaemon macrodactylus are remarkably resistant to infection by the fungus Lagenidium callinectes, a recognized pathogen of many crustaceans. An Alteromonas sp. bacterial strain consistently isolated from the surface of the embryos, produces 2,3-indolinedione (isatin), a compound that inhibits the pathogenic fungus. If exposed to the fungus, bacteria-free embryos quickly die, whereas similar embryos reinoculated with the bacteria or treated only with 2,3-indolinedione live well. The commensal Alteromonas sp. bacteria protect shrimp embryos from fungal infection by producing and liberating the antifungal metabolite 2,3-indolinedione. 相似文献
66.
J C Hay 《Science (New York, N.Y.)》1968,160(826):429-430
A visual target was mloved left and right in exact synchrony with vertical movements of the head. A few minutes' exposure to this novel head-movement feedback led to a change in the visual discrimlination of head movement from object movement. The critical factor in the adaptation is the novel correlation of eye and head movement elicited during the period of exposure. 相似文献
67.
Bovine ulcerative mammillitis caused by a herpesvirus 总被引:2,自引:0,他引:2
68.
Mueller PO Hay WP Allen D Collatos C Watson E 《Journal of the American Veterinary Medical Association》1999,214(4):532-4, 496
A 4-month-old Holstein heifer was examined because of poor growth, weight loss, dysuria, hematuria, pyuria, and a palpable mass in the right caudal quadrant of the abdomen. Clinicopathologic abnormalities included hyperfibrinogenemia, hyperproteinemia, anemia, and leukocytosis, and were consistent with chronic inflammation. Results of ultrasonographic evaluation of the umbilical cord remnants were suggestive of urachal abscess formation. Transabdominal ultrasonography of the kidneys was attempted; the right kidney appeared normal, but the left kidney could not be imaged. The calf was anesthetized and a ventral midline celiotomy was performed. The left kidney was larger than normal, was multilobulated, and contained multiple abscess. It had also broken through the peritoneum and was located in the peritoneal cavity. Unilateral nephrectomy and resection of umbilical cord remnants were performed. The calf recovered without complications and was healthy 5 years later. In this calf, ventral midline celiotomy provided sufficient surgical exposure for removal of the ectopic left kidney and resection of umbilical cord remnants. 相似文献
69.
Urinary cortisol as an additional tool to assess the welfare of pregnant sows kept in two types of housing 总被引:1,自引:0,他引:1
The use of urinary cortisol (UC) as an additional tool to evaluate sows welfare was assessed in two experiments. In a preliminary methodological experiment, the kinetics of cortisol excretion in urine was studied during an Adreno Cortico Trophic Hormone (ACTH) challenge test in 10 pregnant sows. In a second experiment, 96 primiparous sows of an experimental unit were assigned to two different housing systems: 48 animals were housed in individual pens (IP) and 48 animals in collective pens (CP) with 6 animals per pen. UC was measured at the beginning and at the end of pregnancy and compared with other welfare indicators such as behaviour or skin damage. In both experiments, UC was measured using a high pressure liquid chromatography assay. In experiment 1, UC was constant on the day before injection of ACTH, with no variations related to circadian rhythm. It began to rise 2 h after the injection, peaked between 2 to 5 h after then returned to the basal concentration on the day after the injection. In experiment 2, UC concentrations were not different between CP- and IP-housed sows but they were higher in sows exhibiting the less stereotypies in comparison with sows exhibiting the most stereotypies. The results of this study suggest that UC is a good indicator of acute stress, more convenient than plasma cortisol measurement since it is a non-invasive method avoiding restraint or catheterisation of sows. They also suggest that UC could also give additional information on the assessment of chronic stress and improve the evaluation of animal welfare if used in conjunction with other welfare indicators. 相似文献
70.
OBJECTIVE: To evaluate the efficacy of a bioresorbable hyaluronate-carboxymethylcellulose membrane (HA-membrane) for prevention of experimentally induced abdominal adhesions in horses. STUDY DESIGN: Experimental study. ANIMAL POPULATION: Twelve healthy adult horses. METHODS: The effect of an HA-membrane on adhesion formation was evaluated in 12 healthy horses using an established model of serosal trauma to induce adhesions. A ventral median celiotomy and two jejunal resections and end-to-end anastomoses were performed. Two separate jejunal areas were abraded, and three 2-0 chromic gut sutures placed in the abraded areas. In treated horses (n = 6), HA-membranes were applied to the jejunum to completely cover the anastomoses and abraded areas of jejunum. Nontreated horses (n = 6) served as controls. All horses were killed 10 days after surgery. The abdominal cavity was evaluated for adhesion formation. The frequency of intra-abdominal adhesions between groups was compared with a chi2 test with statistical significance set at P < .05. RESULTS: All control horses had intra-abdominal adhesions; fibrous adhesions were associated with both jejunal abrasion sites in 5 horses. One treated horse developed adhesions. There were significantly fewer adhesions in the HA-membrane-treated group (P < .0034). CONCLUSIONS: In this experimental model, application of an HA-membrane to a localized area of serosal trauma reduced the frequency of intra-abdominal adhesion formation. CLINICAL RELEVANCE: Application of an HA membrane may decrease the frequency of adhesions in horses at an increased risk of postoperative adhesion formation. 相似文献