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排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
A monoclonal antibody to an Albanian isolate of plum pox potyvirus (PPV) was obtained (MAbAL), that specifically recognized strain M of this virus. The specificity of MAbAL, assessed by comparative ELISA on 130 PPV isolates of different geographical origin, 22 of which were also tested by comparative IC-PCR, gave consistent and highly reproducible results. MAbAL seems to be elicited by a stable surface determinant that makes it particularly suitable for successful use under a wide range of conditions. MAbAL is an useful addition to the panel of PPV-specific MAbs available to date.  相似文献   
2.
Phytoremediation is a method in which plants, soil microorganisms, amendments, and agronomic techniques interact to enhance contaminant degradation. We hypothesized that bermudagrass (Cynodon dactylon L) and an appropriate amount of N fertilizer would improve remediation of pyrene-contaminated Captina silt loam soil. The soil was contaminated with 0 or 1,000 mg pyrene/kg of soil and amended with urea at pyrene-C:urea-N (C:N) ratios of 4.5:1, 9:1, 18:1, or unamended (36:1). Either zero, one, two, or three bermudagrass sprigs were planted per pot and ?33 kPa moisture potential was maintained. Pyrene concentrations, inorganic-N levels, shoot and root parameters, and pyrene degrader microbial numbers were measured following a 100-day greenhouse study. At a C:N ratio of 4.5:1, the presence of plants increased pyrene biodegradation from 31% for the no plant treatment to a mean of 62% for the one, two, and three plant treatments. With no plants and C:N ratios of 4.5:1, 9:1, 18:1, and 36:1, the mean pyrene biodegradation was 31, 52, 77, and 88%, respectively, indicating that increased inorganic-N concentration in the soil reduced pyrene degradation in the treatments without plants. Additionally, none of the one, two, or three plant treatments at any of the C:N ratios were different with a mean pyrene degradation value of 69% after 100 days. Pyrene resulted in reduced shoot and root biomass, root length, and root surface area, but increased root diameter. The pyrene degrading microbial numbers were approximately 10,000-fold higher in the pyrene-contaminated soil compared to the control. At the highest N rate, bermudagrass increased pyrene degradation compared to the no plant treatment, however, in the unvegetated treatment pyrene degradation was reduced with added N.  相似文献   
3.
A combination of rapid population growth and an accelerating demographic shift from rural to urbanized habitats has resulted in urbanization becoming an increasingly global phenomenon. Two alternate hypotheses describing urban landscape trajectories suggest urbanization is either leading to more homogeneous global patterns or urbanization has dichotomous trajectories of increasing dispersal or coalescence. To better understand the global variation in urban land-cover patterns and trajectories we described the variation in urban landscape structure for 120 cities distributed throughout the world assessed at circa 1990 and 2000. We coupled these data to a low-dimensional neighborhood based model of urban growth using a data-model fusion approach. Trajectories of urban growth were assessed using both the original data and model projections to 2030. The patterns of landscape change were related to both the rate of growth and income. The historical patterns of change showed a trend of increasing landscape complexity and this trend was projected to continue. Urban rate of growth was closely related to the change in several landscape metrics. Income was associated with landscape dynamics and this effect interacted with city size. Large cities were less sensitive to the income effect than small cities. Along with changes to the magnitude of each metric, the overall variation in metrics between years generally exhibited a decrease in variability and this variability was projected to continue decreasing. These findings supported the hypothesis that urban landscapes are becoming more homogeneous and that the dispersal-coalescing dichotomy represent endpoints rather than alternate states of urban growth.  相似文献   
4.
5.
Homeostasis of calcium (Ca) and phosphate (Pi) is maintained by a concerted interplay of absorption and reabsorption via the gastrointestinal tract and the kidney and by storage and mobilization from the bone regulated mainly by parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol and calcitonin. The present study aimed at characterizing the effects of dietary P restriction on bone, vitamin D metabolism and rumen fermentation traits reflecting the endogenous P cycle maintaining the ruminal P supply for microbial metabolism. The experiments were done in eleven female, non-pregnant, non-lactating four- to nine-year-old Black Headed Mutton sheep allotted to two feeding groups: "P-restricted" (0.11% P/kg DM and 0.88% Ca/kg DM) and "Control" (0.38% P/kg DM and 0.88% Ca/kg DM). Dietary P restriction did not lead to hypophosphataemia, probably due to a compensation by bone mobilization, demonstrated by increased serum concentrations of a resorption marker and altered gene expression in bone tissue. In addition, the RNA expression of fibroblast growth factor 23, a bone-derived factor involved in the regulation of vitamin D metabolism, was significantly reduced with dietary P restriction. Furthermore, several genes related to vitamin D metabolism and plasma concentrations of 1,25-(OH)2D were associated with serum concentrations of phosphate (Pi). In the parotid gland, the expression of the Pi transporter NaPi2b was negatively associated with serum Pi and positively with parathyroid PTH expression. Although Pi concentrations in saliva and the gastrointestinal tract were significantly reduced, we found no adverse effects of the P-restricted ration on the production of short chain fatty acids, but slight differences in the production of butyrate as well as its relationship to rumen Pi and ammonia concentrations that might indicate an impact on ruminal fermentation.  相似文献   
6.
A 6-year-old Saint Bernard dog was diagnosed with encrusting cystitis caused by Corynebacterium urealyticum. The infection persisted despite the prolonged use of antimicrobials and surgical debridement of the urinary bladder. Resolution occurred following intravenous vancomycin, urine acidification, and intravesical gentamicin. The challenges involved in the treatment of encrusting cystitis are described.  相似文献   
7.
The present study examined branch and stem characteristics of trees growing around gaps in Norway spruce plantations. Trees located at the edge of gaps with a radius of either 5 m or 7 m either unplanted or with supplementary planting were compared to trees in the original closed plantation. The experiment was carried out in two locations in the south of Sweden and the design included four blocks at each location and one replicate of each treatment in each block. The measurements were carried out on standing and felled trees in 2005 at the time of the first thinning. The results indicate a significant effect of gaps and supplementary planting on the diameter of the largest branch, the number of living branches close to breast height, branch basal area, height to the first living branch and taper. The effect of supplementary planting on branch and stem characteristics was greater in large gaps than in small ones. This study indicated that supplementary planting may be useful in affecting stem-form and branch parameters, although other studies have shown that the trees that result from supplementary planting contribute little to total production.  相似文献   
8.
Preureteral vena cava (circumcaval ureter, retrocaval ureter) occurs in a third of the feline population and has been associated with ureteral strictures in humans. The aim of this retrospective cross‐sectional study was to describe the contrast‐enhanced multidetector row computed tomographic (MDCT) characteristics of presumed preureteral vena cava in a group of cats. Medical records from two institutions located in different continents were searched from 2010–2013 for cases with complete contrast‐enhanced MDCT examinations of the abdomen (i.e. included the entire course of the ureters and prerenal and renal segments of the caudal vena cava) and a diagnosis of preureteral caudal vena cava. For cases meeting inclusion criteria, CT scan data were retrieved and characteristics of the preureteral caudal vena cava were recorded. Presence of concomitant renal or ureteral diseases was also recorded. A total of 272 cats had contrast‐enhanced abdominal CT scans during the study period and of these, 68 cats (22.43 ± 4.96%) had a diagnosis of presumed preureteral vena cava. In all affected cats, a “reverse‐J ureter” was observed, i.e. a ureter running medially at the level of L4–5, passing dorsally to the caudal vena cava and then exiting ventrally between the caudal vena cava and aorta returning to its normal position. Having a preureteral vena cava resulted in an increased risk for concurrent urinary signs (OR = 3.00; CI: 95%; 1.28–6.99; P = 0.01). Findings supported the use of contrast‐enhanced MDCT for characterizing morphology of preureteral vena cava and its relation with ureters in cats.  相似文献   
9.
ABSTRACT

One of the major global trends linked to the process of globalization is the expansion of agro-industry into the humid tropics. Although agro-industry is an important source of income for Brazil, it is also leading to the displacement of local populations and extensive clearing of native vegetation. In this context, we focus on a second trend resulting from globalization in which financial institutions have demonstrated increasing concern with environmental and social responsibility, notably through the inclusion of environmental and social conditions in loans to the agricultural sector. In this article, we provide an assessment of the potential for this type of economic instrument to help reduce the negative impacts of agro-industrial expansion, and how the different actors who are shaping this debate (non-governmental organizations, industries, the finance sector, government) can best help to realize this potential. We evaluate this broader question through the lens of two International Finance Corporation loans to Brazil's Grupo Maggi, the world's largest independently-held soybean exporter. We identify four areas in which private sector self-regulation can improve to realize environmental and social performance goals: (a) Financial institutions and firms can increase the clarity, quality, timeliness, and regularity of monitoring and reporting; (b) Civil society can develop a more sophisticated approach to distinguishing between companies and initiatives that essentially maintain the status quo and those that are trying to improve; (c) Civil society can help to develop simple, standard measures of environmental and social performance of agricultural lands for use by financial institutions and firms in establishing environmental and social management systems; and (d) Governments can develop strong regulations that capitalize on voluntary regulation mechanisms' flexibility and efficiency, as well as developing incentive systems for producers and firms that demonstrate high social and environmental performance in their operations.  相似文献   
10.
A cross-sectional study examined the occurrence of Tritrichomonas foetus, and other intestinal parasites, in feral and shelter cats in Prince Edward Island (PEI). Fecal samples were collected from 100 feral cats, 100 cats from the PEI Humane Society, and 5 cats from a private residence. The occurrence of T. foetus, based on fecal culture, was 0% in feral and shelter cats. A single positive sample was obtained from an owned Abyssinian cat that was imported to PEI. Intestinal parasites were identified via fecal flotation in 76% of feral cats and 39% of cats from the humane society. Feral cats had a higher incidence of Toxocara cati than cats from the humane society (P < 0.001), conversely, shelter cats had a higher incidence of Cystoisospora spp. (P < 0.001). These results suggest that while T. foetus is not of importance in feral and shelter cats in PEI, imported cats could serve as reservoirs.  相似文献   
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