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1.
The objective of this study was to obtain spatial distribution maps of paddy rice fields using multi-date moderateresolution imaging spectroradiometer (MODIS) data in China. Paddy rice fields were extracted by identifying the unique characteristic of high soil moisture in the flooding and transplanting period with improved algorithms based on rice growth calendar regionalization. The characteristic could be reflected by the enhanced vegetation index (EVI) and the land surface water index (LSWI) derived from MODIS sensor data. Algorithms for single, early, and late rice identification were obtained from selected typical test sites. The algorithms could not only separate early rice and late rice planted in the same fields, but also reduce the uncertainties. The areal accuracy of the MODIS-derived results was validated by comparison with agricultural statistics, and the spatial matching was examined by ETM+ (enhanced thematic mapper plus) images in a test region. Major factors that might cause errors, such as the coarse spatial resolution and noises in the MODIS data, were discussed. Although not suitable for monitoring the inter-annual variations due to some inevitable factors, the MODIS-derived results were useful for obtaining spatial distribution maps of paddy rice on a large scale, and they might provide reference for further studies.  相似文献   

2.
This study was undertaken to isolate and characterize the protease activity of human eye lens sample of mature and hyper mature cataract. Samples were collected just after surgery of the cataract lens and were stored at -20°C. The total protein extract was isolated from 5 samples in each case (mature and hyper mature cataract) and clear supernatant obtained after centrifugation was used as an enzyme source. The optimum pH for the proteases of mature cataract was 7.5 while the proteases of hyper mature cataract were recorded for maximum activity at pH 5.5 and 7.5. The optimum temperature for both enzyme sources was 50 °C. Effect of different metal ions such as potassium, lead, silver, zinc and borate was studied. In each case protease activity was increased. Reducing agent e.g. β mercaptoethanol also caused an increase in activity indicating the involvement of sulfhydryl groups. Protease activity was also located on agar plates.  相似文献   

3.
Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of China. The paper is to evaluate soil aggregate stability and to determine the relationship between soil organic carbon (SOC) and soil aggregate stability. Soil samples at 0 cm-20 cm layer were adopted from a long-term (16 a) field experiment including conventional tillage: plain culture, summer rice crop and winter upland crop under drained conditions (PUR-r); and conservation tillage: ridge culture without tillage, summer rice and winter fallow with floodwater layer annually (NTR-f), winter upland crop under drained conditions (NTR-r), and wide ridge culture without tillage, summer rice crop and winter upland crop under conditions (NTRw-r), respectively. Different pretreatments, such as slaking in fast wetting, wetting and subsequent slaking, were applied to simulate the breakdown mechanisms of aggregates in paddy soil. The results show that soil particles contents were mainly consisted of silt (0.050 mm to 1.000 mm) in fraction of 42.9% to 51.2%, sand (0.050 mm to 0.001 mm) in fraction of 28.0% to 31.8%, and clay (〈0.001 mm) in fraction of 17.9% to 25.4%. The amount of aggregate-size was greatly observed in fraction of 2.000 mm-6.720 mm under ridge culture in paddy soil (more than 50$) under slaking and wetting pretreatment. The proportion of soil macro-aggregates (〉0.250 mm) in conservation tillage was greatly higher than that in conventional tillage under subsequent fast slaking treatment. Minimal differences of aggregate stability between slaking in fast wetting and wetting were observed, while significant differences were found between ridge culture and plain culture. The aggregate stability under slaking treatment ranked in the order of NTR-r〉NTRw-r〉 NTR-f 〉 PUR-r, while under wetting was NTRw-r 〉 NTR-r 〉 NTR-f 〉PUR-r. There was a positive correlation between the aggregate stability and SOC concentration under wetting, and a low correlation was observed under slaking pretreatment. Soil exposure with tillage and lack of rice/rape-seed stubble inputs caused declines in aggregation and organic carbon, both of which make soil susceptible to water erosion. Adoption of ridge culture with no-tillage integrated with crop rotation and stubble mulch significantly altered soil organic concentration. It was a valuable conservation practice for soil aggregation and soil organic carbon sequestration on paddy soil.  相似文献   

4.
Octenyl succinic anhydride (OSA) modified early Indica rice starch was prepared in aqueous slurry systems using response surface methodology. The paste properties of the OSA starch were also investigated. Results indicated that the suitable parameters for the preparation of OSA starch from early Indica rice starch were as follows: reaction period 4 h, reaction temperature 33.4℃, pH of reaction system 8.4, concentration of starch slurry 36.8% (in proportion to water, w/w), amount of OSA 3% (in proportion to starch, w/w). The degree of substitution was 0.0188 and the reaction efficiency was 81.0%. The results of paste properties showed that with increased OSA modification, the starch derivatives had higher paste clarity, decreased retrogradation and better freeze-thaw stability.  相似文献   

5.
This study compares the life events perceived as "rites of passage" from adolescence to adulthood by respondents between the ages of 14 and 23 in 3 countries and discusses the possible influences of culture and globalization on these perceptions. Participants include: (1) 250 adolescents from the US (125 males and 125 females); (2) 191 adolescents from southeastern Brazil (70 males and 121 females); and (3) 163 adolescents from Malaysia (76 males and 87 females). These adolescents ranked a variety of life events which may be perceived as indicative of adult status by completing a questionnaire about perceived rites of passage. Although there were similarities among the 3 groups, several differences also emerged. The most commonly noted indicator of adult status for Malaysian youth was physical maturity, followed by completing one's education. Participants from the US cited financial independence as the major indicator of adult status, while those from Brazil cited the ability to make important decisions independently from family and to take responsibility for others, such as children, aging parents or a spouse. Brazilian youth were significantly more likely to cite a love affair and voting in major elections as rites of passage than were participants from the other 2 countries. Participants from the US were significantly more likely to cite military service, and Malaysian youth were significantly more likely to consider completion of education and achieving physical maturity as rites of passage. Gender and age differences within groups were evident on some items, but these were not consistent across groups. Possible explanations for the differences between countries and implications for educators working with adolescents in rapidly changing societies are discussed.  相似文献   

6.
An experimental and model-based study of the effect of rich air/fuel ratios (AFRs) and temperature on the NOx slip of a lean NOx trap (LNT) was conducted in a lean-burn gasoline engine with an LNT after-treatment system. The emissions of the engine test bench and the inlet temperature of the LNT were used as the major inlet boundary conditions of the LNT. The engine periodically operated between a constant lean AFR of 23 with alterable rich AFRs of 10, 11, 12, 13, and 14. A decrease in the rich AFR of the engine strengthened the desorption atmosphere in the LNT, an effect closely related to the number of reductants, and further heightened the NOx desorption of the LNT, but with a penalty in fuel consumption. To eliminate that penalty, the inlet boundary conditions of the LNT were varied by adjusting the inlet temperature within a range between 200 ℃ and 400℃. An increase in inlet temperature heightened the NOx desorption of the LNT, and a NOx breakthrough occurred after the inlet tem- perature exceeded 390 ℃. To control NOx breakthrough, the inlet temperature can be adjusted to offset the strong desorption atmosphere in the LNT commonly created by a rich AFR.  相似文献   

7.
In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (MQL) has been suggested since a decade ago as a means of addressing the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.  相似文献   

8.
Objective: To observe the effect ofangiotensin Ⅱ (Ang Ⅱ) on expression of gap junction channel protein connexin 43 (Cx43) in the proliferation process of vascular smooth muscle cells (VSMCs) during the early stage of arteriosclerosis. Methods: Thirty-two adult male rabbits were randomly divided into 4 groups. Rabbits in Group A were fed common diet while others in Groups B, C, and D were fed high-cholesterol diet. Losartan (10 mg/(kg.d)) and ramipril (0.5 mg/(kg-d)) were added in the diet of Groups C and D, respectively. The animals were sacrificed after 8 weeks and abdominal aortas were removed and dissected. The expression of Cx43 was assayed using RT-PCR and Western Blotting analysis. Results: Cx43 was increased markedly in both protein and mRNA level in Groups B, C, and D fed high-cholesterol diet compared with that in control group (P〈0.01). Cx43 level in losartan or ramipril treated groups was higher than that in control group (P〈0.01, P〈0.05), but lower than that in high-cholesterol diet groups (P〈0.05, P〈0.01). Conclusion: Cx43 level was upregulated in VSMCs during early atherosclerosis. Losartan and ramipril can inhibit the expression of Cx43.  相似文献   

9.
This work analyses the potential role of nitrogen pollution technology of crop systems of Pujiang, County in Eastern China‘s Zhejiang Province, rice and vegetables are important cropping systems. We used a case study approach involving comparison of farmer practices and improved technologies. This approach allows assessing the impact of technology on pollution, is forward looking, and can yield information on the potential of on-the-shelf technology and provide opportunities for technology development. The approach particularly suits newly developed rice technologies with large potential of reducing nitrogen pollution and for future rice and vegetables technologies. The results showed that substantial reductions in nitrogen pollution are feasible for both types of crops.  相似文献   

10.
甘霖 《海外英语》2015,(6):138-140
Meridian is one of Alice Walker’s early work. It tells a story that happened in the American south during the 1960 s and early 70s’. It describes the life of the main character, Meridian Hill, a black woman from a southern town, who got out of the oppression of white society, and ends up in participate in Civil Rights Movement. The paper firstly illustrates the soul of womanism—anti-sexism, anti-racism, sisiterhood as well as the maternity love, then analyzes how these theories permeated into the novel—Meridian. The paper paid attention to the function of this novel on the improvement of Alice Walker’s womanism.In proving that womanism not only permeates into Meridian, but also improved womanism from many perspectives, it comes to the conclusion that Meridian is a novel to improve Alice Walker’s womanism, it serves as the good novel to highlight the African Culture, and made a great contribution for the encouragement of black women to seek for freedom in the society.  相似文献   

11.
Lovastatin production by Aspergillus terreus ATCC 20542 in solid-state fermentation (SSF) was studied. Various substrates were used to evaluate the ability of A. terreus to produce lovastatin. The results showed that either rice or wheat bran was suitable substrate for lovastatin production in SSF. The maximum yield of lovastatin (2.9 mg/g dry substrate) using rice as substrate was achieved after incubating for 11 d at the following optimized process parameters: 50%~60% initial moisture content,pH 5.5,incubation temperature 28 °C.  相似文献   

12.
Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant,Streptomyces ambofaciens XC 2–37, produced 9% more spiramycin than the parent strainS. ambofaciens XC 1–29. The effects of soybean oil and propyl alcohol on spiramycin production withS. ambofaciens XC 2–37 were studied. The potency ofS. ambofaciens XC 2–37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation. The new process withS. ambofaciens XC 2–37 was scaled up for industrial scale production of spiramycin in a 60 m3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.  相似文献   

13.
Field experiments were conducted in farmers’ rice fields in 2001 and 2002 to study the effects of nitrogen (N) management strategies on N use efficiency in recovery (RE), agronomy (AE) and physiology (PE) and redistribution of dry matter accumulation (DMA) and nitrogen accumulation (NA) in two typical rice cultivars in Jinhua, Zhejiang Province. This study aimed mainly at identifying the possible causes of poor fertilizer N use efficiency (NUE) of rice in Zhejiang by comparing farmers’ fertilizer practice (FFP) with advanced site-specific nutrient management (SSNM) and real-time N management (RTNM). The results showed that compared to FFP, SSNM and RTNM reduced DMA and NA before panicle initiation and increased DMA and NA at post-flowering. There is no significant difference between SSNM and FFP in post-flowering dry matter redistribution (post-DMR) and post-flowering nitrogen redistribution (post-NR). These results suggest that high input rate of fertilizer N and improper fertilizer N timing are the main factors causing low NUE of irrigated rice in the farmer’s routine practice of Zhejiang. With SSNM, about 15% of the current total N input in direct-seeding early rice and 45% in single rice could be reduced without yield loss in Zhejiang, China. Project supported by the International Rice Research Institute (IRRI), Swiss Agency for Development and Cooperation (SDC), the Potash & Phosphate Institute and the Potash & Phosphate Institute of Canada (PPI-PPIC), the International Fertilizer Industry Association (IFA), the International Potash Institute (IPI), and 948 Project of the Ministry of Agriculture of China (No. 2003-Z53)  相似文献   

14.
A new site-specific nutrient management approach was developed to break the apparent attainable yield barrier of 6 t·ha−1 in the double rice cropping system of Zhejiang. On-farm experiments involving 21 rice-growing farmer families and NPK long-term experiments commenced in 1997 in the central part of Zhejiang Province to assess the status of soil fertility and productivity under intensive rice-rice cropping. A new site-specific nutrient management (SSNM) approach has been developed for this studied area. Field-specific fertilizer recommendations are calculated considering indigenous nutrient supply, reasonable grain yield targets and corresponding nutrient demand, nutrient balance and nutrient use efficiency, as well as socio-economic factors. The agronomic performance of SSNM was tested against the farmer's fertilizer practice (FFP) in four 1998–1999 cropping seasons. Across seasons and years, SSNM consistently increased plant nutrient uptake, grain yield and profit by about 10%–15% compared to the FFP. Yield levels of 7.5 t·ha−1 or more seem achievable and sustainable through introduction of SSNM and improved extension services in Zhejiang Province. Project supported by the International Fertilizer Industry Association(IFA), the Potash and Phosphate Institute, Canada (PPIC), and International Potash Institute(IPI).  相似文献   

15.
Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator (GPT) was isolated from a cDNA library of immature seeds of rice and named asOsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of 70 amino acid residues. TheOsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000-grain weight. The expression ofOsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6-phosphate imported viaGPT can be used for starch biosynthesis in rice nongreen plastids. Project supported by National Natural Scienc Foundation of China (No.39830250) and Natural Science Foundation of Zhejiang Province (No.2A0106), China. The nucleotide sequence data will appear in the GenBank under accession number AF375053.  相似文献   

16.
Lead concentrations in roots, stems and leaves of accumulating and non-accumulating ecotypes ofSedum alfredii (Hance) were studied through a hydroponic experiment with different Pb concentrations supplied as Pb(NO3)2. Lead concentrations in leaves and stems of the accumulating ecotype were 4–9 times and 3–5 times those of the non-accumulating ecotype, and Pb-accumulated amounts in stems and leaves of the accumulating ecotype were 4–9 times and 8–11 times higher than those of the non-accumulating ecotype, respectively. The results indicated that the accumulating ecotype had better ability to transport Pb from roots to shoots. The subcellular distributions of Pb in the root, stem and leaf tissues were studied using sucrose differential centrifugation. Approximately 50% of Pb contents was found to be associated with the cell wall fraction in stems of the accumulating ecotype and the percentage increased to 80% both in roots and leaves, no matter when plants were grown with different levels of Pb. The results indicated that the distribution of Pb on cell walls of the accumulating ecotype could mainly account for the high tolerance to Pb. Project supported by a Key Project from the Educational Ministry of China (No:02180) and by the Outstanding Young Scientist Grant from the National Natural Science Foundation of China (No: 39925024).  相似文献   

17.
A two-step method was developed to quantitatively assess the infection rate of the entomophthoraceous fungus,Zoophthora anhuiensis (Li) Humber, on the green peach aphid,Myzus persicae (Sulzer). Firstly, a standard time-dose-mortality relationship, established by modeling data from bioassay 1 at varying conidial dosages (0.4–10.4 conidia/mm2) ofZ. anhuiensis F97028, was used to yield an estimate of expected mortality probability at a given dosage. Secondly, biossay 2 was conducted by simultaneously exposing six ≤4-day-old nymphal colonies to a shower ofZ. anhueinsis conidia at each of four dosages (resulting from exposures of 0.3–8.0 min). Subsequently, the colonies were separately immersed in a 0.1% chlorothalonil solution for 0.5 min to disinfect all surviving conidia on the host integument from 1–12 h after exposure under temperature treatments of 15 and 20°C, respectively. The infection rate during a specific period from the end of the exposure to the immersion was then estimated as the ratio of the observed mortality over the expected mortality probability at a particular dosage. The results showed that the infection ofM. persicae fromZ. anhuiensis was highly rapid with little difference between aphid colonies maintained at 15 and 20°C before being immersed in the fungicidal solution after exposure. The first 6-hour period after exposure was most crucial to successful infection of the fungus with the infection rate greatly depending on conidial dosages. It took ≤1 h to infect >50% of the aphids at a dosage of >1.5 conida/mm2 and >90% at >50 conidia/mm2. Project supported by the National Natural Science Foundation of China (No. 39870513) and the Cheong Kong Scholars Programme, State Education Ministry of China  相似文献   

18.
Motivation: It was found that high accuracy splicing-site recognition of rice (Oryza sativa L.) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results: The prediction accuracy we obtained was 87.53% at the true 5′ end splicing site and 87.37% at the true 3′ end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches. Project partially supported by the Start-up Funding of Zhejiang University to Chen Liang-biao  相似文献   

19.
Robinson, McKay, Katayama, and Fan (Contemporary Educational Psychology, 23, 331–343, 1998) reported that women were underrepresented in terms of authorships, editorial board memberships, and editorships in the field of educational psychology based on membership trends. More recently, Evans, Hsieh, and Robinson (Educational Psychology Review, 17, 263–271, 2005) reported that women had made gains as editors but had not kept pace with organizational membership in terms of authorships and editorial board memberships. Our goal in this paper was to further examine women’s participation in educational psychology journals by extending the datasets of Robinson et al. and Evans et al. The number of female authors per article, particularly those from non-US institutions, has continued to increase. However, consistent with Evans et al., although females are continuing to make numerical gains in both authorships—both primary and secondary—and editorial board memberships, their involvement has not kept pace in relation to membership trends.  相似文献   

20.
To assess the influence of cyclosporin A (CsA) and tacrolimus (FK506) on mycophenolic acid (MPA) and correlation analysis of the pharmacokinetic parameters and patient characteristics, clinical outcome in Chinese kidney transplant recipients, the pharmacokinetics of 1000 mg mycophenolate mofetil (MMF) twice daily was measured by high-performance liquid chromatography (HPLC). PKS (Pharmaceutical Kinctics Software) 1.0.2 software package was used for the calculation of pharmacokinetic parameters. The meanC max,t max, and AUC(0–12) were (21.88±10.52) μg/ml, (1.20±0.95) h, and (52.546±13.215) μg·h/ml, respectively. The level of AUC(0–12) in the FK506 group was significantly higher than that in the CsA group. MPA appeared not to be affected by renal function. MPA AUC(0–12) showed statistically significant difference according to the patient's gender. Project (No. 20040462) supported by the Foundation of Education Bureau of Zhejiang Province, China  相似文献   

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