Routing and time-slot assignment in optical TDM networks

Optical time-division multiplexing (O-TDM) networks can provide a finer bandwidth granularity than wavelength-division multiplexing networks, and will play an important role in future all-optical networks. Since optical buffers are expensive, a small buffer size will be the characteristic of O-TDM systems. This paper analyzes the problem of routing and time-slot assignment in O-TDM networks. The results lead to the proposal of a Dijkstra-like shortest-path routing scheme that intends to maximize the performance of an optical network with a small number of optical buffers. Performance evaluation of the proposed scheme is also presented.     

Effect of purified Trichoderma reesei cellulases on formation of cotton powder from cotton fabric

The mode of action of monocomponent purified Trichoderma reesei cellobiohydrolases (CBHI and CBHII) and endoglucanases (EGI and EGII) on cotton fabrics was studied by analyzing the weight loss of the fabric, the reducing sugars, the soluble oligosaccharides and the molecular weight of the cotton powder formed. The impact of mechanical action on these factors was also evaluated. EGI and EGII released the highest amounts of reducing sugars and soluble oligosaccharides in both treatments with or without additional mechanical action. After cellulase treatment without additional mechanical action, all of the cellulases were found to have reduced the molecular weight of cotton poplin powder. When mechanical action was combined with enzyme treatments, only EGII reduced the molecular weight. The weight loss of EG‐treated fabrics was clearly higher than the weight loss of CBH‐treated fabrics with both low and high mechanical action levels. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1917–1922, 2003     

A cesium fountain frequency standard: preliminary results

An atomic frequency standard based on a fountain of cold cesium atoms has been in operation in our laboratory for a few months. Ramsey fringes as narrow as 0.7 Hz have been obtained. The short-term frequency stability, measured against an H-maser, is 3 10^-13 τ^-1/2, probably limited by the local oscillator frequency noise. A preliminary evaluation of some systematic effects shows that cold collisions will be the limiting effect for long-term stability and accuracy. Measurements of this shift presented here, using a magnetooptical trap, show that at low density an uncertainty of about 10 ¹⁵ is obtained. Under these conditions, the number of atoms is large enough to allow a potential stability of 10^-13 τ ^-1/2 to be reached. When optical molasses is used, the initial density is lower and collisional effects are reduced by a factor of three     

Genetics in the OR--implications for perioperative nursing practice

New developments in deoxyribonucleic acid (DNA) technology are increasing understanding of the role of genetics in health and disease. This kind of health information requires that perioperative nurses develop new skills and roles that will enhance the quality of genetic health care they provide to patients, particularly with regard to managing genetic information. Perioperative nurses expand their scope of practice to incorporate a genetic focus into health assessment, patient education, and patient support as they assimilate new genetic information into their daily lives. Perioperative nurses familiar with genetic counseling services--and how and when to refer patients for such services--will ensure that all patients have access to the most current and appropriate genetic information with which to make informed health choices.     

人工举升装置的新进展

本文从三个方面介绍了人工举升装置的新进展。即：有杆泵采油装置，螺杆泵采油装置和气举采油装置。在人工举升装置中，有杆采油装置处于主导地位。本文介绍的九种有杆采油新技术包括：新型固定凡尔罩。三种经改进的盘根盒；泵入口气体分离器。计算机油井监控器，经改进的清蜡装置，聚乙烯油管衬管；处理气井产出水的新方法。三种螺杆泵新技术包括：新型金属定子；防止泵故障的流量控制器和防止倒扣的油管接箍锁定装置。两种气举采油新技术为：连续油管的钢丝绳可回收阀和在美国西得克萨斯油田应用的CO_2气举法。     

Three-dimensional analysis of the vascular system in the rat spinal cord with scanning electron microscopy of vascular corrosion casts. Part 1: Normal spinal cord

Vascular corrosion casts of polyester resin in the normal spinal cord at C4-C6 and C7-T1 were inspected three-dimensionally by scanning electron microscopy in 13 rats. Arteries and veins were easily differentiated by the impression pattern of endothelial nuclei on the casts. The centrifugal arterial system from the sulcal arteries supplied most of the gray and white matter in the ventral and lateral spinal cord. Each sulcal artery supplied only one side of the cord. The average number of sulcal arteries was 2.6 per mm. The centripetal arterial system from the posterior spinal arteries fed the posterior gray and white matter. In contrast with classical concepts, there was no pial arterial plexus on the ventral and ventrolateral surface except for infrequent transverse branches from the anterior spinal artery. In the posterior columns, two types of large veins were identified: the posterior medial septal veins and the posterior oblique veins that drained the posterior columns, medial posterior gray matter, and posterior gray commissure. The remainder of the gray and white matter was drained by the sulcal veins and the radial veins. This method clearly demonstrates the three-dimensional structure of both the arterial and venous system in the rat spinal cord.     

The phenolics of ciders: Bitterness and astringency

The bitterness and astringency of defined procyanidin fractions from bittersweet English ciders were assessed using a paired-comparison tasting technique. The results demonstrate that, while no one procyanidin can be uniquely identified with bitterness or astringency, bitterness is associated with oligomeric procyanidins reaching a maximum with the epicatechin tetramer whereas astringency is characteristic of higher-molecular-weight procyanidins. The effect of presentation media on taste response was also studied. High sugar and buffer strength suppressed the perceived bitterness, whereas ethanol increased bitterness but simultaneously decreased astringency. It is shown that the observed taste differences between two bittersweet ciders and the taste-modifying effect of ethanol can be explained satisfactorily by current theories of taste.     

On-line evidence for elaborative logical inferences in text.

A model of propositional-logic reasoning proposed by M. D. S. Braine, B. J. Reiser, and B. Rumain (1984) claims that inferences such as "p or q; not p /∴ q" are made spontaneously by readers at the moment both premises are available. This claim is inconsistent with some evidence in the text-processing literature that suggests that only those inferences necessary for textual coherence are made spontaneously. In the present study, participants read stories in which a logical inference was not necessary to maintain textual coherence, and inference making was assessed with on-line probes. Two experiments tested logical forms central to Braine et al's model, and both indicated that participants were making the logical inferences. Two further experiments replicated this result with stories that did not begin with thematic titles. These findings support Braine et al.'s prediction that some propositional-logic inferences are made routinely in texts that do not require them for coherence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)