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11.
It would be preferable to use a reliable crop growth model for studies on climate change impact assessment. The objectives of this study was to evaluate simulation performance for two maize models, including CERES-Maize and IXIM models, included in the DSSAT model (version 4.6) in terms of phenology and yield. Two early maturing cultivars, Chalok#1 and Junda# 6, were grown under controlled environment in plastic houses at Suwon, Korea. Each cultivar, which was sown at four different date in 2013 and 2014, was subjected to four sets of temperature conditions including ambient (AT), AT+1.5°C, AT+3°C, and AT+5°C. In simulations of phenology under given conditions, the anthesis date and grain filling ratio were underestimated, especially when temperature was unusually high, e.g., in 2013. The maize models also had poor accuracy in grain yield, which resulted from the fact that these models had relatively large errors in simulation of kernel number and kernel weight under elevated temperature conditions. In addition, both models were not able to simulate the drastic decrease of kernel number due to heat stress around flowering periods. These results indicated that two maize models would need improvements in simulation of crop response to supra-optimal temperature before they would be used to assess the impact of the climate change on maize yield. This studies merits further study to improve algorithms in phenology simulation at supraoptimal temperature.  相似文献   
12.
5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline derivative was synthesized, and its herbicidal activity was assessed under glasshouse and flooded paddy conditions. 5-(2,6-Difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline demonstrated good rice selectivity and potent herbicidal activity against annual weeds at 125 g of a.i. ha(-1) under greenhouse conditions. Soil application of this compound showed complete control of barnyard-grass to the fourth leaf stage at 250 g of a.i. ha(-1). Field trials indicated that this compound controlled annual weeds rapidly with a good tolerance on transplanted rice seedlings by post-emergence and soil application. This compound showed a low mammalian and environmental toxicity in various toxicological tests.  相似文献   
13.
作物模型输入变量的敏感性分析   总被引:3,自引:1,他引:3  
 运行作物模型需要大量的输入变量。为了方便模型用户建立模型变量数据库 ,研究估计了作物模型 ALMANAC主要模型输入变量的重要程度。根据在美国德克萨斯州 8个县主要玉米品种的田间试验资料 ,首先建立了模拟 10年 (1989~ 1998年 )玉米和高粱产量的标准数据库 ,模拟结果与实产吻合程度很好。以此为基础 ,分别分析了产量对太阳辐射、降雨、土壤层厚度、土壤有效水分以及径流曲线数变化的敏感性。结果表明 ,径流曲线数变化对于模拟结果的影响最大 ,其次分别是降雨和太阳辐射。玉米对所有变量变化的敏感性都大于高粱。获得合适的降雨资料 ,准确估计径流曲线数 ,对于作物生长模拟十分重要。  相似文献   
14.
Chlorella is a nutrient-rich microalga that contains protein, lipid, minerals, vitamins, and high levels of lutein. This study evaluated the bioavailability of lutein from Chlorella vulgaris using a coupled in vitro digestion and human intestinal Caco-2 cell model. Lutein bioaccessibility was low, and approximately 75% of total C. vulgaris lutein was not micellized during the digestion process but remained in the insoluble digestate. Microfluidization improved lutein micellization efficiency during C. vulgaris digestion. C. vulgaris was microfluidized at a pressure exceeding 10000 psi, and the cell surface disruption was visualized by scanning electron microscopy. The mean C. vulgaris particle size was reduced from 3.56 to 0.35 μm with the microfluidization treatment. C. vulgaris microfluidization at 20000 psi was three times more efficient for aqueous lutein micelles production as compared with untreated C. vulgaris, and the final lutein content accumulated by intestinal Caco-2 cells was also higher with microfluidization. C. vulgaris lutein stability was not affected by microfluidization. These results indicate that microfluidization may be useful for improving lutein bioaccessibility from C. vulgaris during food processing.  相似文献   
15.
Feline idiopathic cystitis (FIC) is the most common cause of feline lower urinary tract disease (FLUTD). This retrospective, case-controlled study evaluated possible risk factors associated with FIC and compared different clinical presentations in 64 cats with FIC. Several risk factors known to be involved in FLUTD were identified as playing a role in FIC. Of the stressful situations considered, most did not occur with increased frequency in cats with FIC compared to controls, except for a house move. The presence of pyuria, haematuria and an increased urine protein:creatinine ratio were significantly higher in obstructed males compared with non-obstructed males. An obstruction was significantly more likely in cats with struvite crystalluria compared with cats without struvite crystalluria. These findings suggest that urethral plugs might be an important cause or contributing factor of obstruction in FIC. Episodes of FIC seem to occur mainly in susceptible cats in combination with a deficient environment.  相似文献   
16.
BACKGROUND: The spotted wing Drosophila, Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae), is an invasive pest of small‐fruit crops. Unlike most other Drosophila, this insect is able to oviposit into and damage ripe and ripening fruit, making it unmarketable. Because this is a new pest in the United States, it is necessary to identify registered insecticides to manage this insect effectively in conventional and organic production systems. RESULTS: The present laboratory bioassays and field trials identified a number of insecticides representing various modes of action that are effective in controlling D. suzukii. Products that performed well in the laboratory bioassay also performed well in the field, indicating that screening of new chemistries in the laboratory is a worthy exercise. Field application of pyrethoids, organophosphates or spinosyns provided 5–14 days of residual control of D. suzukii. The efficacy of the neonicotinoids as adulticides was not satisfactory compared with the other contact‐mode‐of‐action chemistries. Based on the zero tolerance by the small‐fruit industry and the individual effects mentioned above, neonicotinoids are not currently recommended for D. suzukii management. CONCLUSIONS: There are effective insecticides registered for controlling D. suzukii infestations in susceptible small‐fruit crops. Copyright © 2011 Society of Chemical Industry  相似文献   
17.
Four cultivars of strawberries (Senga Sengana, BFr77111, Elsanta, and Honeoye) were studied for their content of antioxidants, total antioxidant capacity, and low molecular weight carbohydrates in relation to harvest year, ripening stage, and cold storage. For ascorbic acid, chlorogenic acid, ellagic acid, and total antioxidative capacity, measured in both water-soluble and water-insoluble extracts, there was a 2-5-fold variation among cultivars. Unripe berries contained lower concentrations of chlorogenic acid and p-coumaric acid and also quercetin and kaempferol compared with riper berries. During cold storage for up to 3 days, relatively few changes in the concentration of the different antioxidants occurred. The concentrations of several investigated parameters were interrelated, for example, for ascorbic acid and water-soluble antioxidant capacity and for ellagic acid and water-insoluble antioxidant capacity. The dominating sugars in strawberries were fructose and glucose, but considerable amounts of sucrose were also present, and their contents varied among cultivars, giving a predicted glycemic index of approximately 81. Verbascose, raffinose, and stachyose were found in only minor amounts. The study shows that the concentration of a number of bioactive compounds in strawberries varied according to cultivar, ripening stage, and storage. This information should make it possible to select strawberries with an optimal content of bioactive compounds.  相似文献   
18.
Variations in physical and compositional bran characteristics among different sources and classes of wheat and their association with bread‐baking quality of whole grain wheat flour (WWF) were investigated with bran obtained from Quadrumat milling of 12 U.S. wheat varieties and Bühler milling of six Korean wheat varieties. Bran was characterized for composition including protein, fat, ash, dietary fiber, phenolics, and phytate. U.S. soft and club wheat brans were lower in insoluble dietary fiber (IDF) and phytate content (40.7–44.7% and 10.3–17.1 mg of phytate/g of bran, respectively) compared with U.S. hard wheat bran (46.0–51.3% and 16.5–22.2 mg of phytate/g of bran, respectively). Bran of various wheat varieties was blended with a hard red spring wheat flour at a ratio of 1:4 to prepare WWFs for determination of dough properties and bread‐baking quality. WWFs with U.S. hard wheat bran generally exhibited higher dough water absorption and longer dough mixing time, and they produced smaller loaf volume of bread than WWFs of U.S. soft and club wheat bran. WWFs of two U.S. hard wheat varieties (ID3735 and Scarlet) produced much smaller loaves of bread (<573 mL) than those of other U.S. hard wheat varieties (>625 mL). IDF content, phytate content, and water retention capacity of bran exhibited significant relationships with loaf volume of WWF bread, whereas no relationship was observed between protein content of bran and loaf volume of bread. It appears that U.S. soft and club wheat bran, probably owing to relatively low IDF and phytate contents, has smaller negative effects on mixing properties of WWF dough and loaf volume of bread than U.S. hard wheat bran.  相似文献   
19.
Sonographic evaluation of the pancreas was performed in ten healthy research dogs following intraperitoneal fluid administration. Physiological saline solution was aseptically introduced into the peritoneal cavity of each dog to create an acoustic window that would facilitate sonographic delineation of normal pancreatic tissues. Abdominal ultrasound examinations were performed in all dogs before and after the production of the diagnostic hydroperitoneum. Sonograms of the pancreas and other abdominal organs were scored on the basis of image clarity by experienced and novice ultrasonographers. Statistical analysis was then used to compare the effectiveness of each preparation method. A significant difference (P < 0.05) was established between the scores from the diagnostic hydroperitoneum sonograms and the baseline scans performed without intraperitoneal fluid placement. Sonographic visualization scores for the pancreas and other abdominal organs were increased following production of the diagnostic hydroperitoneum. These results indicate that the technique of diagnostic hydroperitoneum will significantly improve ultrasonographic visualization of the pancreas, and may prove useful in the diagnosis of canine pancreatic disease.  相似文献   
20.
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