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991.
Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD; 24 of 25 cases occurred in foals <45 d old; the remaining foal was 90 d old. There were 12 males and 12 females; no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and Hanoverian. Most of the cases (19 of 25) occurred in the spring. There were 9 cases of sudden death; the remaining animals had diarrhea, fever, distended abdomen, depression, weakness, non-responsiveness, and/or recumbency. Gross findings included icterus, hepatomegaly with acinar pattern, serosal hemorrhages, pulmonary edema, and/or fluid content in small and large intestine. Microscopically, all foals had severe, multifocal, necrotizing hepatitis. Necrotizing lymphohistiocytic colitis was observed in 10 of 25 foals, and multifocal necrotizing myocarditis was found in 8 of 25. Gram-negative, Steiner-positive, intracytoplasmic filamentous bacteria were observed in hepatocytes, enterocytes, and myocardiocytes, respectively. PCR detected C. piliforme DNA in the liver (24 of 24), colon (20 of 24), and heart (5 of 25). Our results indicate that necrotic hepatitis is the hallmark of TD in horses; the so-called triad of lesions is not a consistent characteristic of the disease in this species.  相似文献   
992.
曾经如“雨后春笋”般出现的本土地板企业,为产业带来财富的同时.也带来了浮躁的氖围。然而,面对接踵而至的原材料紧缺、退税削减、专利诉讼、趋同竞争等因素,尤其是近一年来海外经济的低迷状态,企业在用自己的思考与行动寻求着改变。他们逐渐远离浮躁,并将多年积累的经验沉淀成为一种求实、务实、扎实的企业内在品质。我的这一想法在广州之行中再次得到了印证。  相似文献   
993.
Increasing food loss and waste (FLW) is a global problem, and efforts are being made to use waste food as potential livestock feed material. The amount of self-supplied feed is lower in Japan than in other countries, and the government recommends FLW use for animal feed. Sake (Japanese rice wine) is a traditional alcoholic beverage. During the sake manufacturing process, large amounts of squeezed solids or “lees” (sake lees) are generated. Sake lees are nutritious and functional, but are prone to spoilage. In this study, we investigated whether sake lees should be mixed with animal feed immediately or after drying. To assess the usefulness of sake lees as a poultry feed ingredient and determine the effect of sake lees on intestinal immunity, we performed a feeding trial with three treatments: a raw sake lees (RSL) diet, dried sake lees (DSL) diet, and control diet. Three-week-old broilers were fed these diets (n=8 per group) for two weeks. We then calculated feed efficiency and performed RT-qPCR to assess the effects of diet on intestinal immunity. The growth performance in the RSL diet group was equivalent to that in the control diet group. The DSL diet became difficult for broilers to eat, resulting in decreased growth performance. In the ileum of RSL-diet broilers, the mRNA expression levels of TGF-β1 and avian β-defensin (AvBD)12 were significantly increased compared to those of control diet broilers (p<0.05), and a significant correlation was observed between the two genes (p<0.05). Our results indicated that sake lees should not be dried and should be mixed immediately with feed, and this sake lees when fed to chicken activates the intestinal immunity. However, sake lees have a lower fat content than corn, and it is thus important to combine sake lees with high-energy feed.  相似文献   
994.
番茄穴盘育苗苗龄的研究   总被引:8,自引:0,他引:8  
在穴盘育苗条件下 ,对番茄的适宜苗龄进行了研究 ,结果表明 ,大龄苗〔60d(天 )〕秧苗素质较差 ,前期产量虽高 ,但总产量偏低 ,小龄苗〔30d(天 )〕总产量最高 ,但前期产量低 ,中龄苗〔4 5d(天 )〕则表现秧苗素质好 ,前期产量较高 ,且总产量与小龄苗相比差异不显著 ,具有较高的生产力。  相似文献   
995.
Landscape Ecology and Species Conservation   总被引:6,自引:0,他引:6  
  相似文献   
996.
An aggregation index (AI) to quantify spatial patterns of landscapes   总被引:43,自引:0,他引:43  
There is often need to measure aggregation levels of spatial patterns within a single map class in landscape ecological studies. The contagion index (CI), shape index (SI), and probability of adjacency of the same class (Qi), all have certain limits when measuring aggregation of spatial patterns. We have developed an aggregation index (AI) that is class specific and independent of landscape composition. AI assumes that a class with the highest level of aggregation (AI =1) is comprised of pixels sharing the most possible edges. A class whose pixels share no edges (completely disaggregated) has the lowest level of aggregation (AI =0). AI is similar to SI and Qi, but it calculates aggregation more precisely than the latter two. We have evaluated the performance of AI under varied levels of (1) aggregation, (2) number of patches, (3) spatial resolutions, and (4) real species distribution maps at various spatial scales. AI was able to produce reasonable results under all these circumstances. Since it is class specific, it is more precise than CI, which measures overall landscape aggregation. Thus, AI provides a quantitative basis to correlate the spatial pattern of a class with a specific process. Since AI is a ratio variable, map units do not affect the calculation. It can be compared between classes from the same or different landscapes, or even the same classes from the same landscape under different resolutions.  相似文献   
997.
A long-term experiment set up by G. W. Dimbleby to test the effect of birch as a soil improver on a heather moor podzol is described. After 30 yr, an acid woodland type of vegetation developed under the birch trees with Deschampsia flexuosa and Vaccinium myrtillus locally dominant. The mean annual dry matter production of stems and branches was approximately 2.9 t ha?1. The raw humus layer removed as an experimental treatment had re-formed. Its pH, about 3.4, had remained unchanged for 15 yr. The mean extractable Ca content of the upper 3 cm horizon of the birch plots and of the control plots under heather had increased and on some of the birch plots the concentrations of exchangeable Ca were somewhat higher than those under heather. The N content of the Ol + Of, Oh and Ea horizons was higher under the birch than under heather but there was no evidence of movement of Fe out of the ironpan under the influence of birch. The profile under birch remained a fully differentiated podzol.  相似文献   
998.
999.
A 20 s exposure to 2450 MHz microwave radiation had a marked differential effect on the viable count of soil micro-organisms, had little influence on numbers of heterotrophic bacteria, but reduced fungal colonies on dilution plates to zero. The growth of fungi from soil particles was also reduced following treatment. Prolonging the exposure to microwave radiation progressively inhibited nitrification and S-oxidation, but stimulated ammonification. Brief exposures (20s) also stimulated S-oxidation and increased the numbers of thiobacilli in soil. Most of these effects are explained by reference to the marked increase in soil temperature resulting from microwave treatment.  相似文献   
1000.
The activity of the ovary-inhibiting hormone in the eyestalks of female prawns, Parapenaeopsis hardwickii, was determined during its ovarian developmental cycle. In the inactive (stage I) and post-spawned phases of ovarian development, the ovary-inhibiting hormone activity was found to be very high. During the phase of full vitellogenesis (stage IV), the inhibiting activity is almost negligible. After spawning (stage V) it is present, but at a lower level than during inactive and post-spawned phases. Hence it is inferred that ovary-inhibiting hormone appears to be responsible for the phase of ovarian quiescence and to control the rate of vitellogenesis.  相似文献   
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