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991.
Geesink GH van Buren RG Savenije B Verstegen MW Ducro BJ van der Palen JG Hemke G 《Meat science》2004,67(1):1-6
Two experiments were done to determine whether short-term supplementation (5 days pre-slaughter) with magnesium acetate, or a combination of magnesium acetate, tryptophan, vitamin E and vitamin C would improve pork quality. In the first experiment the pigs (Pietrain×Yorkshire, n=96) were fed a standard feed or a magnesium supplemented feed for 5 days prior to slaughter. As a possible stress factor half of the animals were slaughtered upon arrival at the slaughterplant whereas the remaining animals were allowed two hours of rest in lairage before slaughter. Magnesium supplementation did not result in an increase in plasma magnesium concentration at slaughter. Omission of lairage resulted in higher plasma glucose concentrations, but plasma lactate concentrations were not affected. Drip loss and ultimate pH were not affected by diet or omission of lairage. Omission of lairage resulted in poorer color characteristics. This effect was prevented by supplementation with magnesium. In the second experiment the pigs (Pietrain×Yorkshire, n=92) were fed a standard feed or this standard feed supplemented with magnesium acetate, tryptophan, vitamin E and vitamin C for 5 days prior to slaughter. Supplementation with vitamin E did not increase muscle vitamin E concentration. Inclusion of supplements in the diet failed to improve water-holding capacity or color characteristics. These results indicate that short-term supplementation with magnesium acetate, tryptophan, vitamin E and vitamin C is of little value in improving pork quality when pigs are not stressed beyond levels associated with routine slaughter procedures. 相似文献
992.
The ideas of parallel imaging techniques, designed to shorten the acquisition time by the simultaneous use of multiple receive coils, can be adapted for parallel transmission of a spatially selective multidimensional RF pulse. In analogy to data acquisition, a multidimensional RF pulse follows a certain trajectory in k-space. Shortening this trajectory shortens the pulse duration. The use of multiple transmit coils, each with its own time-dependent waveform and spatial sensitivity, compensates for the missing parts of k-space. This results in a maintained spatial definition of the pulse profile while its duration is reduced. This paper describes the basic equations of parallel transmission with arbitrarily shaped transmit coils ("Transmit SENSE") focusing on two-dimensional RF pulses. Results of numerical studies are presented demonstrating the theoretical feasibility of the approach. 相似文献
993.
D. Schinkel R.P. de Boer A.J. Annema A.J.M. van Tuijl 《Analog Integrated Circuits and Signal Processing》2004,41(1):13-20
A CMOS temperature switch with uncalibrated high accuracy is presented. The circuit is based on the classical CMOS bandgap reference structure, using parasitic PNPs and a PTAT multiplier. The circuit was designed in a standard digital 0.18 m CMOS process. The temperature switch has an in-designed hysteresis of 1.2°C around a threshold value of 128°C. At the switching-threshold all matched transistors have also matched operating conditions, yielding a temperature threshold that is highly independent of transistor output resistance and supply voltage. The chip area was minimized using a novel and generic strategy. With a chip area of only 0.03 mm2, the onwafer 3 spread of the threshold temperature is 1.1°C. Power consumption is only 15 A at 1 volt supply. 相似文献
994.
Boone Christophe; Carroll Glenn R.; van Witteloostuijn Arjen 《Industrial and Corporate Change》2004,13(1):117-148
We demonstrate how organizational ecology can contribute tostrategic management and managerial practice by using resource-partitioningtheory to make predictions with respect to: (i) the short-runperformance (i.e. growth and profitability) consequences ofbroad (generalist) vis-à-vis focus (specialist) strategies;(ii) the detrimental performance implications of a particularinstance of being strategically stuck in the middle;and (iii) the performance consequences of organizational sizedifferences. We hypothesize that these effects depend on theposition of the organization in resource space. These predictionsare tested by estimating models of growth and profitability,using data on Dutch generalist (national) and specialist (regional)newspapers from 1968 to 1994. The findings show that resource-partitioningtheory provides a dynamic backbone to understand the performanceconsequences of different generic strategies and organizationalsize positions. 相似文献
995.
An essential assumption for the usefulness of basing accident prevention measures on minor incidents is the common cause hypothesis: that causal pathways of near misses are similar to those of actual accidents (such as injuries and damages). The idea of a common cause hypothesis was originally proposed by Heinrich in his seminal book "Industrial Accident Prevention" [McGraw-Hill, New York]. In this paper, it is argued that the hypothesis of similarity of causes for major and minor accidents has become confounded with the interdependence of the ratio relationship between severity and frequency. This confounded view of the hypothesis has led to invalid tests of the hypothesis and erroneous conclusions. The evidence from various studies is examined and it is concluded that the hypothesis has not been properly understood or tested. Consequently, such a proper test was carried out using data from the UK railways which were analysed using the confidential incident reporting and analysis system (CIRAS) 21 cause taxonomy. The results provide qualified support for the common cause hypothesis with only three out of the 21 types of causes having significantly different proportions for the three consequence levels investigated: 'injury & fatality', 'damage' and 'near miss'. 相似文献
996.
Design, synthesis and properties of a degradable polyurethane scaffold for meniscus regeneration 总被引:5,自引:0,他引:5
Heijkants RG van Calck RV De Groot JH Pennings AJ Schouten AJ van Tienen TG Ramrattan N Buma P Veth RP 《Journal of materials science. Materials in medicine》2004,15(4):423-427
Longitudinal lesions in menisci are among the most frequent orthopedic problems of the knee. Repair by simple techniques is only limited to the vascular part of the meniscus. For repair of the avascular part of the meniscus a scaffold, which will assist the body in the formation of new meniscus cell tissue, might be applicable. In this study a biomedical segmented polyurethane with poly(epsilon-caprolactone) as soft segment and 1,4-butanediisocyanate and 1,4-butanediol as uniform hard segments has been synthesised. The material has a micro phase separated morphology and excellent mechanical properties. A porous scaffold was prepared via a combination of liquid-liquid phase separation and salt leaching. The foams prepared combined a very high interconnectivity and porosity with the desired compression modulus. After six months of implantation in the knees of beagles full ingrowth with cells was obtained and it was found that meniscus like tissue had been formed in the scaffold. Moreover, compression behaviour appeared to be comparable to native meniscus tissue. 相似文献
997.
In this work the liquefaction cycle is introduced as a framework to describe the coupled processes that take place in fluid-saturated granular media that lead to liquefaction. The modular formulation of liquefaction makes it possible to test the various processes that contribute to liquefaction separately, and to assemble different formulations of the relevant physics into a numerical model for liquefaction. This view on liquefaction is used here to assess the role of drainage in liquefaction. We present a simple scale analysis of the role of drainage. A numerical implementation of the liquefaction cycle shows, however, that the scale analysis is deceptive for the case when strong spatial variations in the permeability inhibit fluid migration. As an illustration the numerical model is used to quantify the imprint of a low-permeability layer on the liquefaction behavior.We greatly appreciate our conversations with Masami Nakagawa and Vaughan Griffiths about this work. The critical and constructive comments of two anonymous reviewers are very much appreciated. The visit of Annemieke van den Beukel to Golden was supported by the Molengraaff fonds, the Schuurman Schimmel van Outeren Stichting, the Stichting Dr. Hendrik Mullers Vaderlandsch Fonds, and the Trajectum Fonds. 相似文献
998.
Gelinck GH Huitema HE van Veenendaal E Cantatore E Schrijnemakers L van der Putten JB Geuns TC Beenhakkers M Giesbers JB Huisman BH Meijer EJ Benito EM Touwslager FJ Marsman AW van Rens BJ de Leeuw DM 《Nature materials》2004,3(2):106-110
At present, flexible displays are an important focus of research. Further development of large, flexible displays requires a cost-effective manufacturing process for the active-matrix backplane, which contains one transistor per pixel. One way to further reduce costs is to integrate (part of) the display drive circuitry, such as row shift registers, directly on the display substrate. Here, we demonstrate flexible active-matrix monochrome electrophoretic displays based on solution-processed organic transistors on 25-microm-thick polyimide substrates. The displays can be bent to a radius of 1 cm without significant loss in performance. Using the same process flow we prepared row shift registers. With 1,888 transistors, these are the largest organic integrated circuits reported to date. More importantly, the operating frequency of 5 kHz is sufficiently high to allow integration with the display operating at video speed. This work therefore represents a major step towards 'system-on-plastic'. 相似文献
999.
1000.
Anastasios?TombrosEmail author C.J.?van Rijsbergen 《Knowledge and Information Systems》2004,6(5):617-642
The application of document clustering to information retrieval has been motivated by the potential effectiveness gains postulated by the cluster hypothesis. The hypothesis states that relevant documents tend to be highly similar to each other and therefore tend to appear in the same clusters. In this paper we propose an axiomatic view of the hypothesis by suggesting that documents relevant to the same query (co-relevant documents) display an inherent similarity to each other that is dictated by the query itself. Because of this inherent similarity, the cluster hypothesis should be valid for any document collection. Our research describes an attempt to devise means by which this similarity can be detected. We propose the use of query-sensitive similarity measures that bias interdocument relationships toward pairs of documents that jointly possess attributes expressed in a query. We experimentally tested three query-sensitive measures against conventional ones that do not take the query into account, and we also examined the comparative effectiveness of the three query-sensitive measures. We calculated interdocument relationships for varying numbers of top-ranked documents for six document collections. Our results show a consistent and significant increase in the number of relevant documents that become nearest neighbors of any given relevant document when query-sensitive measures are used. These results suggest that the effectiveness of a cluster-based information retrieval system has the potential to increase through the use of query-sensitive similarity measures. 相似文献