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181.
182.
约瑟夫:米兰作为2015年世博会主办城市,您认为世博会能为米兰提供什么机会?特别是城市管理方面,政府有什么预期目标? 卡罗:米兰世博会体现了正面的发展,我们应该遵循米兰精神:在接近城市的传统和渊源的同时与国际接轨.  相似文献   
183.
Pasquale  J. Anderson  E. Muller  P.K. 《Computer》1994,27(3):84-93
New I/O devices with data rates ranging from 10 to 100 Mbytes per second are becoming available for personal computers and workstations. Along with continual improvements in processor, memory, and bus technology, these devices have enabled I/O-intensive applications for desktop computing that require input, processing, and output of very large amounts of data. We focus on an important aspect of operating system support for these applications: efficient transfer of large data objects between the protection domains in which processes and devices reside. A rapidly growing class of I/O-intensive applications is multimedia computing. After we present an I/O-pipeline model, we analyze issues relevant to the design of an operating system inter-domain data-transfer facility. Then we present the design for such a facility. An I/O pipeline is a model of a dynamic computation structure consisting of a sequence of domains: an input domain followed by one or more intermediate domains, and an output domain  相似文献   
184.
In this paper we present X-Learn, an XML-based, multi-agent system for supporting “user-device” adaptive e-learning, i.e. e-learning activities which take into account the profile, past behaviour, preferences and needs of users, as well as the characteristics of the devices they use for these activities. X-Learn is characterized by the following features: (i) it is highly subjective, since it handles quite a rich and detailed user profile that plays a key role during the learning activities; (ii) it is dynamic and flexible, i.e. it is capable of reacting to variations in user exigencies and objectives; (iii) it is device-adaptive, since it decides the learning objects to present to the user on the basis of the device he is currently using; (iv) it is generic, i.e. it is capable of operating in a large variety of learning contexts; (v) it is XML based, since it exploits many facilities of XML technology for handling and exchanging information related to e-learning activities. The paper also reports various experimental results, as well as a comparison between X-Learn and other related e-learning management systems already presented in the literature.  相似文献   
185.
When a filter is placed in front of a double slit illuminated by a primary source of finite extent, the theory of partial coherence predicts that in general the interference fringes do not acquire unit visibility even as the passband of the filter is made arbitrarily narrow. The effect of reducing the filter bandwidth is that the visibility of the fringes tends to the modulus of the spectral degree of coherence and that more interference fringes become visible. A systematic experimental verification of these theoretical predictions is lacking so far and is provided here from the use of a highly sensitive CCD camera.  相似文献   
186.
187.
Interleukin-1beta (IL-1b) is an important immune regulatory factor that in human endometrium plays a role in both menstruation and implantation in the event of pregnancy. It promotes inflammatory-like processes and also stimulates tissue remodelling. We present a cDNA microarray study documenting the major effects of IL-1beta on gene expression in stromal cells from human endometrium. Endometrial stromal cells from five normal healthy women at the mid secretory phase were cultured with or without IL-1beta at 50 and 500 pg/ml for 48 h. cDNA microarrays were used to compare the levels of gene expression in total RNA isolated from cells stimulated with IL-1beta. These cDNA arrays were produced containing 15 164 sequence-verified clones, which included genes known to be important in angiogenesis, immune modulators, apoptosis, cell signalling, extra-cellular matrix (ECM) remodelling and cell cycle regulation. Genes which were regulated by IL-1beta were identified by analysis of the microarray data using the Significance Analysis of Microarrays software package. Upregulated (n = 23) and downregulated (n = 6) different genes were observed, which changed at least 3-fold, at a false discovery rate of less than 2% (P < 0.02). Our results have identified genes regulated by IL-1beta, which are involved in leukocyte recruitment, ECM remodelling and other cellular functions. Changes in three genes, IL-8, colony-stimulating factor 2 and aldoketo reductase family 1 member 1, which were upregulated by IL-1beta, were verified using real-time PCR. Novel functions regulated by IL-1beta in endometrium, including genes involved in free radical protection, and fatty acid metabolism were also identified. These results also provide new insights into the role of IL-1beta in disorders of the endometrium, especially in implantation-related infertility and endometriosis, in which this cytokine plays a major role.  相似文献   
188.
189.
A comparison between 13C NMR spectra of polymer solutions and Fourier transform infrared spectra of polymer films for several ethene-butadiene copolymers, including most butadiene as 1,2-cyclopropane and 1,2-cyclopentane units, is presented. This spectral comparison, also with the help of a low-molecular-mass model compound specifically synthesized for this purpose, has allowed to locate infrared absorbances associated with the cyclic comonomer units. In particular, a satisfactory calibration curve for evaluation of the amount of the reactive cyclopropane units, from the absorbance of the 1020 cm−1 band, has been achieved. An analysis of 1,2-cyclopropane unit reactivity in annealed films, has also pointed out that the presence of remnants of the polymerization catalyst can produce large increase in cyclopropane reactivity.  相似文献   
190.
In Italy, the consumption of raw or slightly cooked mussels represents the most important risk factor for the transmission of hepatitis A virus (HAV). Although there exist effective methods for the bacterial depuration of contaminated mussels, these methods are poorly effective on enteric viruses. The objective of the present study was to evaluate the effectiveness of a closed-circuit depuration system that uses both ozone and UV light for disinfecting water and that allows salinity and temperature, important parameters for the metabolism of mussels (Mytilus galloprovincialis), to be maintained at constant levels. The results showed that this depuration method decreased the viral load (from 1.72 log 50% tissue culture infective dose [TCID50] ml(-1) to <1 log TCID50 ml(-1) within 24 h and from 3.82 log TCID50 ml(-1) to <1 log TCID50 ml(-1) within 48 h). However, in both cases, after 120 h of depuration, a residual amount of virus capable of replicating in cells was detected. These results show that depuration, even if performed with advanced systems, may not guarantee the absence of virus.  相似文献   
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