Liquid core modal interferometer integrated with silica waveguides

An integrated structure is demonstrated as a refractive index sensor. The structure consists of a liquid-filled elliptical microchannel embedded in silica glass and integrated with waveguides. The microchannel features entry points that are open to the top surface of the device and distinct from the optical input. The structure allows light to couple from a solid-core input waveguide to the liquid-core waveguide formed by the microchannel, and back to a solid-core output waveguide. Bimodal interference allows the structure to be sensitive to the refractive index of the liquid, with a full beat corresponding to a refractive index change of /spl sim/10/sup -4/. The structure allows the direct integration of optical fluids with silica waveguides for sensing and optical processing applications.     

A solution to Plato's problem: The latent semantic analysis theory of acquisition, induction, and representation of knowledge.

How do people know as much as they do with as little information as they get? The problem takes many forms; learning vocabulary from text is an especially dramatic and convenient case for research. A new general theory of acquired similarity and knowledge representation, latent semantic analysis (LSA), is presented and used to successfully simulate such learning and several other psycholinguistic phenomena. By inducing global knowledge indirectly from local co-occurrence data in a large body of representative text, LSA acquired knowledge about the full vocabulary of English at a comparable rate to schoolchildren. LSA uses no prior linguistic or perceptual similarity knowledge; it is based solely on a general mathematical learning method that achieves powerful inductive effects by extracting the right number of dimensions (e.g., 300) to represent objects and contexts. Relations to other theories, phenomena and problems are sketched. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Star wars and strategic defense initiatives: work activity and health symptoms of unionized bank tellers during work reorganization

Work activity and health symptoms of bank tellers whose work was undergoing reorganization were examined during a university-union study of the health effects of work in women's traditional jobs. Data were gathered through collective and individual interviews, analysis of work activity, and a questionnaire administered to 305 tellers. Employees worked in a standing posture over 80 percent of the time. More than two-thirds frequently suffered pain in back, legs, and feet. The average teller had been involved in 3.7 robberies as a direct victim and six as a witness. Work required feats of memory and concentration. In order to meet job demands, tellers engaged in supportive activities and teamwork. The introduction of individualized objectives threatened the employees' ability to collaborate and induced distress. More than twice as many tellers as other female workers in Québec experience psychological distress (Ilfeld scale), related to: robbery during the past two years (odds ratio = 1.7; confidence interval = 1.0-2.9); difficult relations with superiors (O.R. = 2.6; C.I. = 1.3-5.3); and full-time work (O.R. = 2.3; C.I. = 1.3-3.9). Diverse methods enriched the analysis, and union participation allowed the proposal of concrete correction measures.     

Induction of cyclooxygenase-2 by parathyroid hormone in human osteoblasts in culture

OBJECTIVE: Parathyroid hormone (PTH) induced bone resorption by osteoclasts depends on the presence of osteoblasts. PTH induced production of prostaglandins by osteoblasts and induction of bone resorption by prostaglandins suggest that these autacoids may be implicated in the effects of PTH on bone. Our objective was to determine if the increase in prostaglandin production induced in human osteoblasts by PTH is due to an increase in cyclooxygenase-2 (COX-2) expression. METHODS: Primary cultures of human osteoblasts were obtained from specimens of trabecular bone. Confluent cells were treated with PTH, dexamethasone or compound NS-398, a specific COX-2 inhibitor. The concentration of prostaglandin E2 (PGE2) in the supernatants was determined by radioimmunoassay and COX-2 mRNA levels evaluated by Northern blot. RESULTS: PTH induced COX-2 mRNA expression and PGE2 production. These effects were time and concentration dependent and were inhibited by dexamethasone. Compound NS-398 reduced PGE2 production to the same extent as dexamethasone, and neither compound had an additive effect on this variable. CONCLUSION: These results show that PTH induces COX-2 expression in human osteoblasts in culture and suggest that this isoenzyme is the main factor in the control of prostaglandin synthesis in these experimental conditions.     

Distributed predicate detection in series-parallel systems

This paper addresses the problems of state space decomposition and predicate detection in a distributed computation involving asynchronous messages. We introduce a natural communication dependency which leads to the definition of the communication graph. This abstraction proves to be a useful tool to decompose the state lattice of a distributed computation into simpler structures, known as concurrent intervals. Efficient algorithms have been proposed in the literature to detect special classes of predicates, such as conjunctive predicates and bounded sum predicates. We show that more general classes of predicates can be detected when proper constraints are imposed on the underlying computations. In particular, we introduce a class of predicates, defined as separable predicates, that properly includes the above-mentioned classes. We show that separable predicates can be efficiently detected on distributed computations whose communication graphs satisfy the series-parallel constraint     

<Emphasis Type="Italic">trans</Emphasis> Fatty Acid Content of Canadian Margarines Prior to Mandatory <Emphasis Type="Italic">trans</Emphasis> Fat Labelling

Dietary trans fatty acids (TFA) are of major concern because of their adverse effects on blood lipid levels and coronary heart disease. In Canada, margarines were significant sources of TFA during the 1980s and 1990s. However, this is expected to change with increased public awareness over their adverse health effects and the introduction of new legislature to include TFA content on the Nutritional Facts table of food labels. In this study, the TFA content of the top-selling 29 Canadian margarines, which represented 96.3% of the market share, was determined by capillary gas-liquid chromatography in order to assess the influence of regulatory development during the 3-year transition period between the announcement of new food labelling regulations in Canada that require mandatory declaration of the trans fat content in most pre-packaged foods in January 2003 and its enforcement on 12 December 2005. The 29 margarines included 15 tub margarines made from non-hydrogenated vegetable oils (NHVO-tub margarines), 11 tub margarines made from partially hydrogenated vegetable oils (PHVO-tub margarines) and three print margarines, which were also made from partially hydrogenated vegetable oils (PHVO-print margarines). The 15 NHVO tub-margarines accounted for 71% of the total margarine market share and generally contained less than 2% TFA (mean value 0.9 ± 0.3% of total fatty acids). The mean total TFA contents of PHVO-tub margarines and PHVO-print margarines, were 20.0 ± 4.5% and 39.6 ± 3.5%, and their market shares were 19.3 and 6.0%, respectively. Although during the last 10 years, increasing number of soft tub margarines that contained very little trans fats have been made available in Canada, the PHVO-tub- and -print margarines still contain high levels of trans fats similar to those margarines that were sold in the 1990s. The market share data suggest that the margarines prepared using NHVO and containing almost no TFA were preferred by Canadians over those margarines prepared using PHVO, even before the mandatory declaration of TFA content came into effect on 12 December 2005.     

Evaluation Challenges and Directions for Information-Seeking Support Systems

ISSSs provide an exciting opportunity to extend previous information-seeking and interactive information retrieval evaluation models and create a research community that embraces diverse methods and broader participation.     

Liquid-Core Directional Couplers Integrated With Silica Waveguides

Liquid-core directional couplers are fabricated in silica-on-silicon, monolithically integrated with silica waveguides at the input and output ports. The device output as a function of device length is shown experimentally using a series of devices of different lengths with toluene as the core medium. The experimental results agree with simulations, and the device is shown to be polarization insensitive. Applications in sensing, filtering and optical processing are discussed     

Microchannel-Based Refractive Index Sensors Monolithically Integrated With Silica Waveguides: Structures and Sensitivities

Refractive index sensors using self-forming microchannels embedded in borophosphosilicate glass and monolithically integrated with silica waveguides are presented. Fabricated devices presented include solid-core and liquid-core directional couplers, liquid-core modal interferometers, Mach-Zehnder interferometers, segmented waveguides, and microchannel grating devices. Sensitivities of these devices are calculated and compared with each other and to other well-known devices. Experimental characterizations show that the performance of fabricated devices agrees well with calculations.