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排序方式: 共有402条查询结果,搜索用时 93 毫秒
1.
《The Journal of Applied Poultry Research》2006,15(2):312-325
This study examined growth responses and meat yield of broilers provided a 3- or 4-phase feeding schedule formulated to moderate or high nutrient density. Four dietary treatments were implemented consisting of high or moderate nutrient density diets that were provided for the duration of 3 phases (1 to 17, 18 to 35, and 36 to 56 d) or 4 phases (1 to 17, 18 to 35, 36 to 46, and 47 to 56 d).Provision of a 3-phase schedule did not alter growth performance, meat yield, or diet cost per final BW. Broilers receiving high nutrient diets had improved growth rate and feed conversion from 1 to 35 d. In the 3-phase schedule, birds given the high nutrient density diets had advantages in BW gain and pectoralis minor breast weight. Market changes in meat prices impact differences in gross feeding margins between diets formulated to high or moderate nutrient density more than variation in diet cost. 相似文献
2.
A field experiment was conducted to find out the critical physiological stages of irrigation schedules inducing better growth, physiological efficiency and seed yield potential of berseem ( Trifolium alexandrinum L., Var. S-99-1). For this purpose eight irrigation treatments were made comprised of four treatments of three irrigation (W1 , W2 , W3 and W4 ), three treatments of four irrigation (W5 , W7 and W8 ) and one treatment of five irrigation (W6 ) at various physiological stages i. e. regeneration, flower initiation, full bloom, seed initiation and advance seed development stage.
Thus based on the experimental results the physiological role of watering in berseem seed production could be discussed as:
With-holding of irrigation either at regeneration or at full bloom stage developed potential water stress in plants as indicated by high proline content of irrigation treatments — W4 , W1 and W7 ; and further brought out disturbance on the formation of carotene, synthesis of water soluble sugar and translocation of sugar towards reproductive organs during grain development stage. These stresses adversely affected the plant growth and flowering behaviour. The irrigation at seed initiation stage increased the seed yield. Continuous irrigation did not appear to be useful. Thus it can be concluded that irrigation at three critical physiological stages i. e. regeneration, full bloom and seed initiation was found to be essential for obtaining potential seed yield of berseem. 相似文献
Thus based on the experimental results the physiological role of watering in berseem seed production could be discussed as:
With-holding of irrigation either at regeneration or at full bloom stage developed potential water stress in plants as indicated by high proline content of irrigation treatments — W
3.
明确温度与米蛾成虫生殖和卵发育的关系并进行模式化表达,为人工智能规模化繁育米蛾及利用其卵进行天敌昆虫的繁殖提供科学依据。在室内5个恒温条件下(15℃、20℃、25℃、30℃、35℃)测定米蛾卵的发育历期、孵化进度、孵化率及成虫产卵量、产卵动态、寿命等。结果显示,米蛾卵在15℃条件下停滞发育(不能孵化),在20~35℃的温度范围内,卵的发育历期与温度呈负相关,卵的发育速率总体趋势符合Logistic曲线模型V=0.25/[1+exp(5.06-0.24t)](R=0.9993,F=358.06,P=0.0373),孵化率与温度的关系符合二项式关系模型y=1/[0.0144+526644.37exp(-t)](R=0.9471,F=26.14,P=0.0145),在试验温度范围内,米蛾成虫单雌产卵量有随着温度升高呈现先增加后降低的趋势,且米蛾单雌产卵量(y)与温度(t)的关系符合二项式模型y=-2.38t2+128.42t-1383.58(R=0.9941,F=84.28,P=0.0117),成虫寿命亦随着温度的升高逐渐缩短。米蛾雌虫产卵适宜温度范围是25~30℃,最适温度为26.98℃,卵发育的适宜温度范围是20~30℃,最适温度为26.90℃。 相似文献
4.
Hu Lide Yang Dan Wang Shilong 《保鲜与加工》1993,(6):58-64
After researching the function requirements of the planning and scheduling in manufacturing cells, the paper advanced a control structure with three phases, i. e. planning , scheduling and dispatching. The paper represented in detail the main purposes, requirements and scheduling actions in each phase. It suits to general machining FMSs. 相似文献
5.
The standard Linux is a typical time-sharing system, it has a poor real-time performance. But according to the applications of the Linux OS are expanding on real-time domain, it becomes necessary to enhance the performance of the Linux system. This paper analyses the schedule policies and schedule algorithms of the Linux kernel, and discusses several different kinds of methods about enhancing real-time performance of the Linux system from the total Linux system. They authors summarizes the current research's developments of the Linux system. 相似文献
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华北典型区冬小麦区域耗水模拟与灌溉制度优化 总被引:3,自引:0,他引:3
以经校验Aquacrop模型模拟了不同土壤条件下冬小麦水分与产量响应关系,结合北京大兴区土壤分布及其冬小麦实际种植情况,对模型模拟结果进行区域尺度拓展,以此为基础分析了研究区不同灌溉制度下冬小麦耗水量、产量及水分生产率的变化规律,并推荐了与华北地区水资源实际情况相适宜的冬小麦亏缺灌溉制度。结果表明:应用Aquacrop模型能较好模拟冬小麦生育期内土壤墒情和冠层覆盖度的动态变化过程及其生物量与产量情况,可利用经校验后的模型进行冬小麦水分与产量响应关系研究。灌溉定额在300 mm范围内,随着灌溉量增加,耗水量增大;在灌水次数相同条件下,灌溉日期不同,因蒸腾量变化导致耗水量差异显著。在相同处理下总体上降水多年份产量较高,而不同处理之间随着灌溉量增加产量增大;在灌水次数相同情况下,灌溉关键生育时段选择对冬小麦产量形成及水分生产率提高至关重要。以冬小麦增产提效为原则,在灌1水情况下重点保障拔节-抽穗阶段的需水;灌2水情况下重点保障返青-拔节、抽穗-乳熟阶段需水;灌3水情况下重点保障返青-拔节、拔节-抽穗、抽穗-乳熟阶段需水。针对华北水资源严重短缺实际,建议北京大兴区冬小麦采用灌2水的亏缺灌溉制度,较灌4水情况下的灌溉量与耗水量分别减少140、65 mm,能确保75%产量。可见,在与华北类似的资源性缺水区域,选择适宜亏缺灌溉制度,能大幅降低区域灌溉量与耗水量,在稳定区域冬小麦产量及涵养地下水源方面具有重要的现实意义。 相似文献
10.
基于当前的移动aget问题以及网格计算特点,在前人的理论基础上,文中结合agent 技术和网格计算研究基于移动agent的网格计算管理模型,运用系统中各个元素进行agent 建模。介绍移动agent 技术,以及网格计算管理模型应具备的特征,最后提出基于移动Agent 的网格计算管理模型来解决网格中资源管理,作业调度,负载平衡的问题。仿真结果表明,基于agent 的网格计算管理模型仿真能够细致地刻画系统特性,降低系统对网络带宽的严格要求,同时也缩短时间延迟,提高服务响应速度。 相似文献