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排序方式: 共有472条查询结果,搜索用时 343 毫秒
461.
Current control of scab and mildew of apple in the UK requires the routine application of fungicides at 7 - 14-day intervals to achieve the blemish-free fruit required by the market. Such practices are generally effective, but with increased public concern about pesticides and rising costs to the grower, they are now less acceptable. The use of disease-warning systems offers scope for optimizing fungicide use by better timing of sprays. Adem? is a PC-based system that warns of the risk of scab, mildew, Nectria fruit rot and canker and fireblight. In a 'key stage' strategy, warnings by Adem? for scab and mildew integrated with practical pest and disease control resulted in similar or better control than a routine programme, with the additional benefit of reduced fungicide inputs and costs even in seasons exceptionally favourable for these diseases. Maximum savings in fungicide use were made by applying sprays curatively in response to scab warnings. However, this approach resulted in increased disease incidence to the crop and scab infection of fruit even in seasons unfavourable for scab attack. 相似文献
462.
Gholizadeh Amir Dehghani Hamid Akbarpour Omidali Amini Ashkboos Sadeghi Kaveh Hanifei Mehrdad Sharifi-Zagheh Aram 《Journal of Crop Science and Biotechnology》2022,25(5):611-619
Journal of Crop Science and Biotechnology - Salinity stress is one of the most important abiotic stresses which reduce crop production worldwide. In this study, 17 morphological and agronomic... 相似文献
463.
干旱区绿洲农业结构与水资源合理利用研究——以新疆策勒绿洲为例 总被引:4,自引:0,他引:4
绿洲农业是依靠灌溉发展起来的生态系统。干旱地区地表水资源共同特点是春、秋季供水紧张,夏季相对富裕;但种植业产业结构上用水又集中在春季,水的利用矛盾重重。本文分析新疆策勒绿洲近50年农业统计资料,结合课题组调查收集的第一手资料,在充分分析干旱区绿洲农业结构与水资源利用特点的基础上,用资源最优分配模型和线性优化模型方法,提出了绿洲农业结构、作物布局和水资源利用最佳方案,为干旱区绿洲水资源合理利用、区域经济发展提供科学依据。 相似文献
464.
AM Rao E Richter S Bandow B Chase PC Eklund KA Williams S Fang KR Subbaswamy M Menon A Thess RE Smalley G Dresselhaus MS Dresselhaus 《Science (New York, N.Y.)》1997,275(5297):187-191
Single wall carbon nanotubes (SWNTs) that are found as close-packed arrays in crystalline ropes have been studied by using Raman scattering techniques with laser excitation wavelengths in the range from 514.5 to 1320 nanometers. Numerous Raman peaks were observed and identified with vibrational modes of armchair symmetry (n, n) SWNTs. The Raman spectra are in good agreement with lattice dynamics calculations based on C-C force constants used to fit the two-dimensional, experimental phonon dispersion of a single graphene sheet. Calculated intensities from a nonresonant, bond polarizability model optimized for sp2 carbon are also in qualitative agreement with the Raman data, although a resonant Raman scattering process is also taking place. This resonance results from the one-dimensional quantum confinement of the electrons in the nanotube. 相似文献
465.
Background: Various frequencies of sperm aneuploidy are reported in sperms of subfertile patients compared to normal individuals. Moreover, sperm DNA damage is shown to be associated with male infertility. In this study, the rate of DNA damage and frequencies of aneuploidy in sperms of subfertile patients was investigated. Methods: Semen samples were obtained from healthy normal and subfertile (oligozoospermia, asthenozoospermia, and oligoasthenozoospermia) men. The frequency of aneuploidy was assessed using primed in situ labeling (PRINS) analysis with specific primers for chromosomes 18, 21, X, and Y. Sperm DNA damage was assessed using alkaline comet assay. Results: The mean frequencies of disomy for the patients were significantly higher than normal for all chromosomes (P<0.01). The extent of DNA damage in sperms of subfertiles was significantly higher than in normal individuals (P<0.001). The obtained results indicated that higher rate of DNA damages led to higher frequency of chromosomal disomy except for asthenozoospermia samples which exhibited higher rate of DNA damage and lower frequency of chromosomal disomy. Conclusions: These results demonstrate that men with oligozoospermia and oligoasthenozoospermia have an elevated risk for chromosome abnormalities in their sperm, particularly sex chromosomes. DNA damage might be involved in the process of malsegregation of chromosomes.Asthenozoospermia, DNA damage, Primed in situ labeling (PRINS), Comet assay 相似文献
466.
467.
Hamid Abbas El Faki Dr. L. V. Venkatarama H. S. R. Desikachar 《Plant foods for human nutrition (Dordrecht, Netherlands)》1984,34(2):127-133
The effect of different types of processing such as boiling, pressure cooking, puffing, frying, germination, and germination followed by cooking on the protein and carbohydrate digestibility of chickpea, horsegram and cowpea were studied in in vitro systems. In the case of chickpea, the protein digestibility was not significantly improved by any of the treatments. However, for horsegram and cowpea, improvement in protein digestibility was observed after some of the different processing treatments. Frying decreased the protein digestibility in all of the pulses. All of the treatments, except germination, caused a marked increase in in vitro carbohydrate digestibility. 相似文献
468.
Toxicity in three dogs from accidental oral administration of a topical endectocide containing moxidectin and imidacloprid 总被引:1,自引:1,他引:0
Three dogs were presented with a history of oral administration of a topical endectocide containing imidacloprid and moxidectin. They were diagnosed with imidacloprid and moxidectin intoxication, having ingested doses ranging from 7.5 to 1.4 mg/kg of imidacloprid and 1.9 to 2.8 mg/kg of moxidectin. The three dogs were affected to different degrees of severity, but all displayed signs of ataxia, generalised muscle tremors, paresis, hypersalivation and disorientation. Temporary blindness occurred in two cases. The three dogs were tested for the presence of the multi-drug resistance 1 gene deletion, which can cause an increased sensitivity to the toxic effects of moxidectin, and were found to be negative. Treatment included gastrointestinal decontamination, intravenous fluid therapy and benzodiazepines to control muscle tremors. All three dogs made a complete recovery within 48 h of ingestion. 相似文献
469.
Mycobacterium farcinogenes is the causal agent of bovine farcy, a chronic infectious disease of zebu cattle in some parts of tropical Africa. Whole
cell homologous antigen of M. farcinogenes was used in the standardization and evaluation of an enzyme linked immunosorbent assay (ELISA) for the detection of circulating
antibodies against bovine farcy using sera from confirmed bovine farcy and from bovine farcy-free cattle. The cut-off optical
density (OD) value was decided at 1.8 using filter 405nm after one hour of incubation at 37°C. Accordingly, 115 out of 124
(92.7%) serum samples from clinically proven bovine farcy cattle were reported sero-positive. Sera from cattle infected with
M. avium and M. paratuberculosis revealed OD value <1.8, indicating the differential diagnostic ability of M. farcinogenes antigen. Our test sensitivity was 92.7% and specificity was 97%, therefore could be routinely employed to support early clinical
diagnosis, epidemiological surveys and for screening animals before exportation to farcy-free regions. 相似文献
470.
伊犁河谷盐渍化区土壤盐分离子的空间变异特征 总被引:3,自引:0,他引:3
利用地统计学,结合地理信息系统(GIS),在面积约为400 km2的伊犁河谷典型研究区总共布设了土壤取样点60个,测定土壤表层(0~20 cm)总盐分及其组成(Ca2+、Mg2+、K+、Na+、SO42-、Cl-、CO32-、HCO3-)的空间变异性规律.结果表明:总盐分,Ca2+,HCO3-为正态分布,其余盐分离子符... 相似文献