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51.
对转入除草剂抗性基因bar及来自病毒TuMV的/VIa基因的不结球白菜纯合株系二代进行了田问生物学性状调查,结果表明,转基因白菜的植物学性状与其未转基因对照材料相比,无明显差别;但在涉及其生存竞争力的一些生物学性状,如发芽势、花粉活力、种子库存力等方面,比对照材料弱,其经济性状也比对照稍差.获得的转基因性状——除草剂抗性,能稳定遗传,并在田间很好表达;NIa基因介导的TuMV抗性在露地开放栽培条件下,不能很好表达,转基因株染病较重.对产生以上现象的原因进行了分析讨论.图3表5参16  相似文献   
52.
阿特拉津对不同肥力土壤磷酸酶的影响   总被引:6,自引:0,他引:6  
通过室内恒温培养法,研究除草剂阿特拉津对4种长期定位施肥处理下的土壤的磷酸酶活性的影响。试验结果表明,在阿特拉津质量分数不同和处理时间长短不同的情况下,阿特拉津对土壤磷酸酶的活性既有激活作用又有抑制作用。在试验过程中,4种不同肥力的土壤其磷酸酶活性随着处理时间的延续而呈现出“降低→升高→降低→升高”的消长趋势。不同阿特拉津质量分数对磷酸酶的影响没有规律,同一质量分数处理既有激活作用,也有抑制作用。在4种不同肥力的土壤中,磷酸酶活性最高的是以氮、磷、钾无机肥配合有机肥施用的土壤。  相似文献   
53.
汪振双  苏昊林 《中国环境科学》2018,38(10):3801-3807
基于生命周期评价方法,考虑混凝土重复再生利用的环境影响分配,对重复再生混凝土的性能和环境影响进行研究,并基于功效系数法优化出混凝土最佳重复再生次数.研究结果表明,再生混凝土的坍落度,强度和电通量随着重复再生循环次数的增加而下降,经3次重复再生后,混凝土28d立方体抗压强度为33.3MPa,满足设计要求,而坍落度和电通量与普通混凝土相比,分别减小和增大了38.9%和85.7%;混凝土材料的生态效率随着混凝土重复再生次数的增加而提高,混凝土材料的GWP、CED和CMR的值均随着混凝土重复再生次数的增加而降低,降低幅度从高到低依次为:CMR > GWP > CED;综合考虑混凝土的坍落度,混凝土抗压强度、电通量、GWP、CED和CMR等6个指标,4种混凝土配合比情景中,混凝土总功效系数从高到低依次为:一次再生混凝土 > 二次再生混凝土 > 三次再生混凝土 > 普通混凝土.  相似文献   
54.
Using multiwave survey data collected among 251 financial sales professionals, we tested whether involuntarily working more from home (teleworking) was related to higher time‐based and strain‐based work‐to‐family conflict (WFC). Employees' boundary management strategy (integration vs. segmentation) and work–family balance self‐efficacy were considered as moderators of these relationships. Data were collected one month before, three months after, and 12 months after the implementation of a new cost‐saving policy that eliminated employees' access to office space in a centralized work location. The policy resulted in employees being forced to work more from home. A voluntary telework program had been in effect before the new policy, implying that working more from home as a result of the new policy was involuntary in nature. Results revealed that involuntarily working more from home was associated with higher strain‐based WFC but not higher time‐based WFC. However, moderator analyses revealed that the positive association between involuntarily working more from home and both types of WFC was significantly stronger among employees with weaker self‐efficacy in balancing work and family. Boundary management strategy had no detectable moderating effect. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
55.
Abstract

Rapid, inexpensive, sensitive, and selective enzyme‐linked immunosorbent assays (ELISAs) now are utilized in environmental science. In this laboratory, many ELISAs have been developed for pesticides and other toxic substances and also for their metabolites. Compounds for which ELISAs have recently been devised include insecticides (organophosphates, carbaryl, pyrethroids, and fenoxycarb), herbicides (s‐triazines, arylureas, triclopyr, and bromacil), fungicides (myclobutanil), TCDD, and metabolites of naphthalene and toluene. New rapid assays have been developed for mercury.  相似文献   
56.
Abstract

Gypchek®, the gypsy moth (Lymantria dispar L.) nucleopolyhedrosis virus product, is manufactured by the United States Department of Agriculture (USDA) Forest Service, and Animal and Plant Health Inspection Service under controlled conditions in a laboratory strain of gypsy moth larvae. Gypchek was registered with the U.S. Environmental Protection Agency in 1978 as a general use pesticide to control gypsy moth. This product has been the subject of intense research and development targeted toward maximizing efficacy while minimizing the cost of production and application. The current Gypchek tank mix is applied at 1.25 × 1012occlusion bodies (OB's) per hectare for each of two applications (3‐days apart) at 18.7 litres/ha per application.  相似文献   
57.
Abstract

Two Daphnia magna offsprings (animals from the first and third brood) whose parentals (F0‐generation) were exposed during 21 days to different tetradifon (4‐chlorophenyl 2,4,5‐trichlophenyl sulfone) concentrations, were transferred to a pesticide free medium during 21 days (recovery period). The algae Nannochloris oculata (5x105 cells/mL) was used as food. In this recovery study, survival, growth and reproduction (mean total young per female, mean brood size, onset of reproduction and mean number broods per female) were assessed as individual parameters and the intrinsic rate of natural increase (r) as population parameter, for F1 generation (1st and 3rd broods). Reproduction was still reduced in F1 (1st and 3rd broods) generation daphnids from parentals (F0) exposed to 0.18 mg/L tetradifon and higher concentrations even after 21 days in clean water. However, survival was not significantly different (p>0.05) in those F1 offsprings from parentals pre‐exposed to the acaricide. Growth was still reduced in F1 daphnids from parentals pre‐exposed to 0.10–0.44 mg/L tetradifon. The intrinsic rate of natural increase (r) was still affected in Fl generation daphnids, specially in those from the third brood. Therefore, Fl generation D. magna offsprings from a parental generation (F0) previously exposed to the acaricide tetradifon were not able to recuperate completely when a recovery period of 21 days was allowed.  相似文献   
58.
The effects of extrinsic rewards on creative performance have been controversial, and scholars have called for the examination of the boundary conditions of such effects. Drawing upon expectancy theory, we attend to both reinforcement and self‐determination pathways that reveal the informational and controlling functions of creativity‐related extrinsic rewards. We further identify the individual dispositions that moderate these two pathways. Specifically, we propose that extrinsic rewards for creativity positively predict creative performance only when employees have high creative self‐efficacy and regard such rewards as important. We likewise propose that extrinsic rewards positively affect the intrinsic motivation of employees with an internal locus of control, thus enhancing their creative performance. Results based on a sample of 181 employee–supervisor dyads largely supported these expectations. The current analysis enriches the creativity literature by combining different perspectives in a coherent framework, by demonstrating the positive effects of extrinsic rewards on intrinsic motivation, and by demonstrating that the rewards–creativity relationship varies across employees depending on their individual differences. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
59.
Abstract

[Carbonyl‐ C]methabenzthiazuron (MBT) was applied to growing winter wheat in an outdoor lysimeter. The amount applied corresponded to 4 kg Tribunil/ha. 140 days after application the 0–2,5 cm soil layer was removed from the lysimeter. This soil contained about 40 % of the applied radioactivity. Using 0,01 M CaCl2 solution or organic solvents, the extractable residues were removed from the soil. The bioavailability of the non‐extractable as well as aged residues remaining in the soil was investigated in standardized microecosystems containing 1.5 kg of dry soil. During a 4 weeks period the total uptake (4 maize plants/pot) amounted up to 3,6; 2,2; and 0,9 % of the radioactivity from soils containing aged MBT residues, MBT residues non‐extractable‐with 0,01 MCaCl2 or MBT residues non‐extractable with organic solvents, respectively. About 20 % of the radioactivity found in maize leaves represented chromatographically characterized parent compound. At the end of the plant experiment the soil was extracted again with 0,01 M CaCl2 and with organic solvents. The soil extracts and also the organic phases obtained from the aqueous fulvic acid solution contained unchanged parent compound.  相似文献   
60.
ABSTRACT: A 0.31-ha pond was treated with 5.0 mg/l dipotassium endothall on May 31, 1973, and the effects of this treatment on the rooted aquatics, on bluegill reproduction, survival, and growth, and on the buildup of endothall residues in bluegill flesh was investigated. The treatment eliminated Myriophyllum exalbescens, Ceratophyllum demersum, Potamogeton crispus, and Anacharis canadenis during the first season, however, all but C. demersum became reestablished the following year. Little endothall was incorporated into edible bluegill flesh. The dipotassium endothall did not affect the number of young-of-the-year (YOY) bluegills produced by the original adult stocking during the year of treatment and the year following treatment and did not affect the reproduction of first generation bluegills. The survival of adult and first generation bluegills was not affected by the herbicide. Bluegills were slower growing in the treatment than the control pond, when similar densities were present in each pond. It is not known whether this was due to some unknown effect of the dipotassium endothall or to other factors.  相似文献   
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