972 resultados para 443
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该文报道了笼养条件下出生的20胎41仔(26♂♂, 15♀♀)间蜂猴的生长发育的研究, 其研究内容及结果如下:(1)体重、体长、前肢长、后肢长、耳长和尾长的生长方程及头骨的瞬时增长率, 表明间蜂猴属快速生长的早熟类群. (2)幼猴到成猴毛色有一个由浅变深的过程, 面部皮肤(包括耳、鼻、眼圈)及手足皮肤从幼猴到成猴有一个明显的变化, 幼猴为浅粉红色, 成猴为黑色. (3)初生幼仔门齿、犬齿、第1前臼齿已破龈萌发, 15日龄左右乳齿长齐; 170-200日龄恒齿长全. (4)600-720日龄性成熟。
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A map is provided showing the location of milkfish rearing facilities in the Philippines. Most of the 17,443 milkfish broodstocks are located in central Philippines. A table shows details as to the rearing facility (cage, pen, pond, tank), number of broodstocks, and age. There are 13,420 broodstocks in ponds; 2,081 in cages; 842 in tanks, and 1,100 in pens. The youngest is 3 years, the oldest 23 years old.
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Understanding the performance and manner of functioning of existing products is at the base of new product development activities. In engineering design the term function is generally used to refer to the technical actions performed by a product. However, products accomplish a wider range of goals. This research explores the opportunity to describe and model, through the concept of function, product actions across four dimensions including technical, aesthetic, social and economic. The research demonstrates that non-technical functions can be represented through active verbs and nouns and modelled using a method known as the Function Analysis Diagram (FAD). The research argues that when technical, aesthetic, social and economic perspectives on product development are considered as different types of function, stakeholders have a common language to communicate which can benefit design collaboration.
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Recent developments in modeling driver steering control with preview are reviewed. While some validation with experimental data has been presented, the rigorous application of formal system identification methods has not yet been attempted. This paper describes a steering controller based on linear model-predictive control. An indirect identification method that minimizes steering angle prediction error is developed. Special attention is given to filtering the prediction error so as to avoid identification bias that arises from the closed-loop operation of the driver-vehicle system. The identification procedure is applied to data collected from 14 test drivers performing double lane change maneuvers in an instrumented vehicle. It is found that the identification procedure successfully finds parameter values for the model that give small prediction errors. The procedure is also able to distinguish between the different steering strategies adopted by the test drivers. © 2006 IEEE.
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The plant circadian clock is proposed to be a network of several interconnected feedback loops, and loss of any component leads to changes in oscillator speed. We previously reported that Arabidopsis thaliana EARLY FLOWERING4 (ELF4) is required to sustain this oscillator and that the elf4 mutant is arrhythmic. This phenotype is shared with both elf3 and lux. Here, we show that overexpression of either ELF3 or LUX ARRHYTHMO (LUX) complements the elf4 mutant phenotype. Furthermore, ELF4 causes ELF3 to form foci in the nucleus. We used expression data to direct a mathematical position of ELF3 in the clock network. This revealed direct effects on the morning clock gene PRR9, and we determined association of ELF3 to a conserved region of the PRR9 promoter. A cis-element in this region was suggestive of ELF3 recruitment by the transcription factor LUX, consistent with both ELF3 and LUX acting genetically downstream of ELF4. Taken together, using integrated approaches, we identified ELF4/ELF3 together with LUX to be pivotal for sustenance of plant circadian rhythms. © 2012 American Society of Plant Biologists.
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The capability to automatically identify shapes, objects and materials from the image content through direct and indirect methodologies has enabled the development of several civil engineering related applications that assist in the design, construction and maintenance of construction projects. This capability is a product of the technological breakthroughs in the area of image processing that has allowed for the development of a large number of digital imaging applications in all industries. In this paper, an automated and content based construction site image retrieval method is presented. This method is based on image retrieval techniques, and specifically those related with material and object identification and matches known material samples with material clusters within the image content. The results demonstrate the suitability of this method for construction site image retrieval purposes and reveal the capability of existing image processing technologies to accurately identify a wealth of materials from construction site images.
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利用14C标记1,2,7,8-四氯代二苯并二噁英(1,2,7,8Tetrachloro[U—14C]dibenzodioxin,14C1,2,7,8TCDD)初步研究了其在鲤体内的分布和代谢规律。14C1,2,7,8-TCDD溶解于丙酮/植物油中,腹腔暴露。暴露1、2、4、8、12d后取样,肝脏、胆汁、腹腔脂肪等消化制样后用液闪仪测量放射性活度。肝脏和胆汁内的放射性活度同步变化,都是第8d达到峰值后下降。腹腔脂肪内1—2d放射性明显高于随后取样的样品。肝和腹腔脂肪的分布量之比呈现“S”型变化趋势。暴露4d
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采用opaopoopq等系列44个随机引物对鲤亚科与亚科的几个种类进行随机扩增多态DNA(RAPD)扩增,通过对电泳结果进行系统分析,得出各种间遗传距离分支图.按节点的遗传距离最大数值0.232可以分出亲缘关系最远的两个群体,即由两种普通鲤为一群体,以及由岩原鲤、倒刺和白甲鱼组成的另一群体.从节点间遗传距离数值叠加计算可以得出岩原鲤与其他各种鱼类亲缘关系,遗传距离由近到远分别是:岩原鲤与倒刺(0.344)<岩原鲤与白甲鱼(0.388)<岩原鲤与普通鲤(0.443),岩原鲤与倒刺的遗传距离最小,这一
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分不同时间 ,收集经人工感染了蛙病毒的样蛙 ,取其心、肺、肾、肠、脾、肝六种组织 ,并通过免疫组化方法进行检测。结果分别在感染了病毒 3d、9d、1 1d后的幼蛙这六种组织中 ,由表及里观察到了深色的阳性信号 ,从而测定了病毒在入侵组织中的存在部位。其中 ,肺和肠组织中阳性信号最强 ,呈灶性分布 ,其余四种组织中的阳性信号则呈散在分布。在未注射病毒的幼蛙阴性对照组六种组织中没有检测到阳性信号。
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通过野外采样,室内培养、观察、鉴定。研究了沙坡头地区藻类多样性和分布特点,并为当地藻类资源利用提出建议.研究发现沙坡头地区藻类植物共计40种(包括1变型),其中蓝藻17种,绿藻10种,硅藻9种,裸藻4种,全为普生种,陆地生境中种类最丰富.亚气及陆地生境中蓝藻在种类数(除灌溉林地结皮)、生物量方面占主导地位;贫瘠水体生境中硅藻占主要地位,营养较丰富水体中绿藻处于优势地位.另外,陆生生境中多以具鞘微鞘藻Microcoleusvaginatus为优势种,小席藻Phormidiumtenue为主要种.
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在中国科学院封丘农业实验站研究了粘土、沙壤上、轻壤上等土壤中的藻类组成、分布和营养需求.结果表明共有56个种,其中分离纯化了33个种.藻类物种多样性随土壤中有机肥料或无机N.P.K肥的增多而增加.相同的种类在不同时间有不同的营养需求,可以据此阐明土壤藻类群落组成变化与土壤肥力的关系.