Mediation of contraction in rat cauda epididymidis by alpha-adrenoceptors

Subtypes of alpha-adrenoceptors responsible for contractions of the rat cauda epididymidis were studied in vivo by micropuncture using a servo-nulling pressure transducer system. Administration of both non-selective and selective alpha-adrenoceptor agonists in doses of 1-40 microg noradrenaline kg(-1) body weight (BW), 1-100 microg clonidine kg(-1) BW, or 100-800 mg methoxamine kg(-1) BW enhanced contractions of the proximal cauda epididymidis in a dose-response manner. The potency of the agonists were noradrenaline > or = clonidine>methoxamine. Pre-treatments with selective alpha(1)-adrenoceptor antagonist (prazosin) and alpha(2)-adrenoceptor antagonist (yohimbine) at the doses of 400 and 800 microg kg(-1) BW, respectively, had very little effect on spontaneous contractions, but effectively blocked the responses to the maximal doses of methoxamine and clonidine. The responses could not be explained by the systemic effects of agonists and antagonists. The results suggest that contraction of the proximal cauda epididymidis of rats is mediated by both alpha(1)- and alpha(2)-adrenoceptors. The latter appears to be more abundant.     

The activation of mechanisms linking judgements of work design and management with musculoskeletal pain

The report of work-related musculoskeletal pain may be related to worker evaluations of the design and management of work through two mechanisms: one biomechanical and the other stress-related. This study of engineering workers (n = 204) explored the validity of these mechanisms using sequential logistic regression. Analyses suggested that workers' ratings of the adequacy of the design and management of their work were related to their report of work-related musculoskeletal pain. However, the mechanisms appeared to be activated in certain conditions. The reporting of pain in the upper body was both biomechanically- and stress-related, whereas that in the lower body was only biomechanically-related. It is argued that the mechanism activated appeared to be determined by the anatomical location of the pain, and probably the variance shared between the different aspects of work design and management, on the one hand, and the mechanical load of the job, on the other.     

Software corrections of vocal disorders

We discuss how vocal disorders can be post-corrected via a simple nonlinear noise reduction scheme. This work is motivated by the need of a better understanding of voice dysfunctions. This would entail a 2-fold advantage for affected patients: Physicians can perform better surgical interventions and on the other hand researchers can try to build up devices that can help to improve voice quality, i.e. in a phone conversation, avoiding any surgical treatment. As a first step, a proper signal classification is performed, through the idea of geometric signal separation in a feature space. Then through the analysis of the different regions populated by the samples coming from healthy people and from patients affected by T1A glottis cancer, one is able to understand which kind of interventions are necessary in order to correct the illness, i.e. to move the corresponding feature vector from the sick region to the healthy one. We discuss such a filter and show its performance.     

NAVSTAR全球定位系统卫星空间环境的设计要求和方案的发展

NAVSTAR全球定位系统（GPS）卫星星座为美国军队和各商业用户提供全球导航支持。已经设计了两代卫星（Ⅰ批和Ⅱ／Ⅱ-A批）并投入了使用，第3代（Ⅱ-R批）已经准备发射，第4代（Ⅱ—F批）正在生产组装。从第一次发射开始，在技术先进性和轨道实验方面就着重于改善以后发射的卫星的设计要求和设计方案。考虑了那些直接与具体的空间环境有关的要求，并注意它们对提出的定位设计方案的影响。可以看到针对光化学污染、航天器带电和辐射衰减的轨道实验使得设计更灵活，并使其具有更长的寿命和更强的功能。     

球迷玩家必备：足球特色硬件心动展示

什么叫铁杆球迷．什么叫与众不同？到了世界杯，咱球迷玩的就是张扬。球衣、球鞋、足球、旗帜缺一不可．身边用的IT硬件也要有足球特色才行。各个硬件厂商同样明白这个道理．融合足球魅力的个性产品已经呈现在我们面前。[编者按]     

配件行情

笔记本电脑整机的价格体系再次崩溃．5999元、4999元这样的字眼不断充斥市场．价格降低了．配置上自然也要做一番功夫。毕竟成本不能压低的话．就要亏本了。笔记本电脑内存方面．即使是4999元也用上256MB容量．不过笔记本电脑硬盘本来逐渐减少的30GB容量型号再次在市场上热起来．成为不少低配机型的标配。除了这两大件以外．安全锁和读卡器等配件由于选购的用户多了．也开始有放量销售的迹象．不过价格略显混乱。     

用MDBT分析纳米Zn及其合金

应用高能球磨机械合金化方法制备纳米Zn及Zn—Al合金体材料，采用拉伸实验和MDBT实验对这些材料的样品的机械性能进行测量分析．结果表明：球磨3～5h获得的Zn-0．6％Al含金具有很好的塑性．室温下球磨3h所得的纯Zn比液氮温度下球磨3h加室温球磨6h所得的纯Zn具有更好的塑性．     

BLOSSOMS: Building Lightweight Optimized Sensor Systems on a Massive Scale

As a joint effort between the Chinese Academy of Sciences and the Hong Kong University of Science and Technology, the BLOSSOMS sensor network project aims to identify research issues at all levels from practical applications down to the design of sensor nodes. In this project, a heterogeneous sensor array including different types of application-dependent sensors as well as monitoring sensors and intruding sensors are being developed. Application-dependent power-aware communication protocols are also being studied for communications among sensor nodes. An ontology-based middleware is built to relieve the burden of application developers from collecting, classifying and processing messy sensing contexts. This project is also developing a set of tools allowing researchers to model, simulate/emulate, analyze, and monitor various functions of sensor networks.     

5000元中端特色配置

点评：整套配置侧重于游戏性能，对显卡进行了强化。Sempron 2600 性价比出色，继承了KB核心出色的性能，采用更先进的90nm制程，超频性能强劲。昂达NF4X为nForce4 4X芯片，并板载了网卡和声卡，690元可谓超值。显卡采用了PCI-E接口的蓝宝Radeon X700，搭配128MB 2.0ns GDDR3显存，足以应付目前的各种游戏。飞利浦107H6外形时尚，采用飞利浦一贯的外观设计。     

平台2015:Intel处理器及平台在下一个十年的演化

毫无疑问,近年来计算技术取得了长足的进步。但是,在未来的十年,主流计算技术中新的工作量、使用模式的出现及变化对未来的计算平台提出的要求,与过去十年所取得的进展也差不多,这些巨大的要求包括:更高的性能、更低的功率密度、更好的功能可扩展性。倘若出现这些使用计算机的震撼性的变化,我们怎样定义和构架未来的计算平台,就将不得不做出引人注目的改变。要整体地理解和满足的,不仅仅有计算的需要,而且还有接口以及系统基础设施的需要。Intel对这三个基础平台要素的演化的长期设想,以及驱动演化的架构的创新和核心能力,即是我们称之为平台2015(Platform2015)的内容。除了考察相关的趋势、使用、平台处理含意之外,本文将集中在平台2015的计算单元,描述Intel微处理器架构在未来十年的演化。