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排序方式: 共有1070条查询结果,搜索用时 15 毫秒
941.
利用Flash 8.0的脚本语句制作了一个旋转塔,并能随鼠标进行移动,制作中重点运用了影片剪辑的制作、获取鼠标位置及设置对象位置等知识。  相似文献   
942.
In order to explore the effect of strain on diverging post‐hatch muscle properties, muscle regulation during embryo development was investigated in selected and unselected breeds. Four broiler strains were used: JingNing (JN) chicken (a Chinese native chicken), HuangYu (HY) broiler, BaiYu (BY) broiler and Hyline layer (commercial crossbred chickens). Results showed that the four breeds had almost the same characteristic during different incubation periods. BY broilers moved more than JN and Hyline layers from Hamburger & Hamilton stage (HH)24 to HH31 (P < 0.05). HY broilers moved more than JN and Hyline layers from HH27 to HH31 (P < 0.01). All the embryos were heavier daily from HH24 to ED18 (P < 0.05); broilers presented greater body weights than JN and hyline layers (P > 0.05); broilers presented smaller fiber diameter than JN chickens before HH31 (P > 0.05). From then on, JN chicken exhibited smaller fiber diameter compared to the broilers (P > 0.05). Western blotting indicated all the breeds had continuous insulin‐like growth factor‐I (IGF‐I) expression, with the highest expression level in broilers from HH19 to HH24 and highest expression level in JN chicks from HH27 to HH31. The results indicated that the diverging growth among breeds was already shown in embryonic stages; the different expression patterns of IGF‐I may be involved in cell proliferation and differentiation.  相似文献   
943.
分析肌肉酸痛生理反应出现的原因,了解乳酸生成的过程,通过深层次的剖析,使我们进一步清晰了肌肉酸痛和乳酸有着密切关联。也由此使我们知道如何消除或缓解这一现象的出现,为以后的生活、工作、学习提供良好的身体状况。  相似文献   
944.
滨海盐渍土水盐运动室内实验研究及治理对策   总被引:12,自引:3,他引:12  
对滨海盐渍土水盐运动规律及其影响因素进行了实验研究,初步获得淋洗脱盐过程中3个盐峰阶段;同时利用相关分析和通径分析,取得了土壤盐分含量及主要盐分离子和土体构型、粘粒含量等对水盐运移的影响程度。提出了因地制宜、综合治理的对策。  相似文献   
945.
Zimmer M, Schreer JF, Power M. Seasonal movement patterns of Credit River brown trout (Salmo trutta).
Ecology of Freshwater Fish 2010: 19: 290–299. © 2010 John Wiley & Sons A/S Abstract – Movement habits in riverine populations of brown trout vary among watersheds. Thus it is important to identify factors influencing differences in individual behaviour so as to improve the information resource base available for the design of river‐specific management strategies. Such information is particularly needed in the rapidly urbanising watersheds of eastern North America where relatively little is known about anthropogenic influences on brown trout populations. In this study, we examined the influence of water temperature on brown trout behaviour in the Credit River in south‐central Ontario, Canada with respect to seasonal movement patterns. Observed patterns of movement were also correlated with variations in river discharge and habitat quality. Forty‐three radio‐tagged, adult brown trout were tracked in a confined 39.8 km portion of the Credit River from 15 May 2002 to 28 July 2003. Fish were captured in three sections of the river that differed in distance downstream and habitat quality. Fish size had little impact on movement patterns. However, there was considerable variation in seasonal movement with upstream movements to summer positions, maintenance of summer positions, downstream and often extensive movements in fall. Also observed was maintenance of winter positions and repeated upstream movements in late spring‐early summer to previously used summer positions. The elaborate movement behaviour in the Credit River population was attributed to seasonal changes in thermal habitat quality. Fish tagged in less suitable thermal habitats moved significantly more than fish from more suitable thermal habitats.  相似文献   
946.
Abstract –  We studied summer movement patterns of creek chubs, Semotilus atromaculatus, in a low-gradient, sand-bottomed stream on the western plains of the United States. Creek chubs were highly associated with patches of cover consisting of wood or macrophytes. Movements among 37 patches in a 1.1-km segment were assessed in a mark-recapture study. Over 2-week intervals, 44% of recaptured fish changed patches. Net distances moved ranged from 4 to 606 m, median distance moved was 49 m. Of fish recaptured repeatedly during the four sampling periods, most (65%) changed patches at least once, but few were consistently mobile. Inter-patch distance was an important variable with a negative effect on creek chub movements. Inter-patch cover was less important, but had a positive effect on movements. Frequent, short-distance movements among habitat patches in summer are a component of the ecology of creek chubs and the spatial arrangement of patches, and intervening stream conditions appear to mediate those movements.  相似文献   
947.
单点入渗过程不能反映不同尺度下森林土壤系统对地面径流量的调节和转化作用,该文采用水文分析法研究坡面径流场的入渗规律,期望获得较大面积上的平均入渗参数,并将此参数运用于不同尺度下的地面径流量及其过程的计算.   相似文献   
948.
Under an extremely arid condition,a PVC greenhouse was built on the top of Mogao Grottoes in gobi area.The results of 235-day constant extraction of condensed water on the greenhouse film and soil water content showed that 2.1 g/(m2·d) groundwater moved up and exported into the soil,and a phreatic water evaporation existed in the extreme dry area where the groundwater is buried deeper than 200 m.After a prolonged export,the soil water content in the greenhouse was not lower but obviously higher than the original control ones.According to the monitored parameters including relative humidity and absolute humidity of soil,and temperature outside and inside the greenhouse,it was found that there is the available condition and mechanism for the upward movement of groundwater,and also it can be sure that the exported water was not from the soil and atmosphere outside the greenhouse.Phreatic water,an important source for soil water,interacts with atmosphere moisture via soil respiration.Soil salinity also has important effects on soil water movement and spatial-temporal heterogeneity.The extremely dry climate,terrestrial heat and change of upper soil temperature are the fundamental driving forces of water transportation and phreatic water evaporation in the Groundwater-Soil-Plant-Atmosphere Continuum(GSPAC) system.  相似文献   
949.
Dynamics of large wood in an eastern U.S. mountain stream   总被引:1,自引:0,他引:1  
Large wood (LW) is an important feature in many streams in northeastern North America, yet the dynamics (recruitment, movement, and export) of large wood remain largely undocumented for streams in this region. In this study we quantify the dynamics of LW in 400 m of a second-order, high gradient, boulder-dominated stream in the eastern Adirondack Mountains, NY. Characteristics and location of all LW (>1-m length, >10-cm diameter) in the 400-m study reach were initially recorded and pieces were individually tagged in November 2000. Subsequent surveys were conducted in late summer/fall of 2001, 2003, and 2004. Twenty-six% of the 112 pieces of LW initially tagged moved 5.0 m or more during the 4 years of this study. Mobile wood was, on average, shorter than non-mobile wood. Nearly all mobile wood was shorter than the 8.0-m bankfull width of the stream. From 2000 to 2004, 2.16 m3 (0.54 m3 100 m−1; 43 pieces) of LW entered the study reach and 0.7 m3 (0.18 m3 100 m−1; 13 pieces) left the stream. Retention of wood in debris dams was key to reducing potential export. For this stream, located within a second-growth mixed northern hardwood riparian forest that is approaching maturity, the net wood accumulation rate was estimated as ranging from 0.09 to 0.15 m3 100 m−1 year−1. Our data support previous observations that LW length strongly influences its potential to move in high gradient streams, though debris dams can reduce LW movement rates and movement distances for wood of all sizes.  相似文献   
950.
Ramularia collo‐cygni (Rcc) is becoming an increasing problem for barley growers across Europe. However, the life cycle of the pathogen is only slowly being elucidated. In this study, Rcc DNA was detected in a number of harvested seed samples from 1999 to 2010, with mean levels peaking in winter barley samples in 2009. A number of experiments were carried out to determine whether the pathogen could move from barley seed to seedlings, and also from seed through the developing plant and into the subsequent generation of seed, both in controlled experiments and in field trials. Results from testing of seed indicated that the fungus is widespread at the end of the growing season in harvested grain samples and can be transmitted to developing plants from infected seed stock. Examination of infected seedlings did not reveal the presence of spores but fungal structures were found within the leaf. The location of the fungus within seed was examined, with Rcc DNA found in both embryo and non‐embryo tissue. The implications for barley production of the pathogen being seedborne are discussed.  相似文献   
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