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Von eBay bis Xbox Live — wer im Internet unterwegs ist, nutzt viele (Teil-) Identit?ten. Um Waren zu verkaufen oder Dienste anzubieten, tritt man anders auf, als wenn man einfach nur online spielen m?chte. Pseudonyme helfen die Privatsph?re zu wahren. Doch nicht immer ist die Modifikation von Identit?tsmerkmalen zul?ssig.  相似文献   
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Comments on the article by J. Macnamara and G. Austin (see record 1994-05070-001) suggesting that Piaget seriously misinterpreted the significance of children's documented difficulties in correctly responding to tasks involving conservation of quantity. It is shown that Macnamara and Austin make some basic errors in their analysis of the Piagetian position and that their alternative theory of how children learn to conserve is both inconsistent with empirical evidence and epistemologically untenable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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Add-drop filters are demonstrated using silica-on-silicon optical waveguide technology. This device consists of a full directional coupler subdivided by Mach-Zehnder sections. Tapering of the coupling coefficients is experimentally shown to dramatically reduce the filters' sidelobes. Only one photolithographic step is required using the silica planar waveguide technology, yielding accurate wavelength control of the filters. Excellent agreement between measurement and design was achieved  相似文献   
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BACKGROUND: This study is part of the European Community Respiratory Health Survey (ECRHS), which uses a common methodology in different areas throughout the world. This paper describes the prevalences of reported asthma, asthma-like symptoms and nasal allergies, their relationships to age group and sex, and the relationships of asthma-like symptoms to current asthma, in the general population aged 20-44 years of three French urban areas. METHODS: The study population of 2804 subjects in Grenoble, 3774 in Montpellier and 3152 in Paris (18th district), randomly selected from electoral rolls, answered a postal questionnaire (stage I of ECRHS). The response rates were 77.8%, 68.6% and 74.4%, respectively. RESULTS: The prevalences were approximately 14% for wheezing, 16% for chest tightness and 4.5% for nocturnal shortness of breath in the three areas. Asthma attacks in the last 12 months were reported by 2.7% of subjects in Grenoble, 3.5% of subjects in Montpellier and 4.0% of subjects in Paris (P = 0.02). For nasal allergies, the prevalences were 28.0%, 34.3% and 30.8%, respectively (P < 0.001). Asthma was inversely correlated to age (higher prevalence in the youngest) but was not related to sex. Neither age distribution nor sex ratio explained the differences between areas. Among the asthma-like symptoms, wheezing and nocturnal shortness of breath correlated strongly with asthma, chest tightness correlated moderately and nocturnal coughing correlated poorly. CONCLUSION: The prevalences observed were higher than expected from previous comparable French studies in young adults. These results are consistent with the hypothesis of a recent increase of asthma and allergies.  相似文献   
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Considering the critical contribution of your rectifier to the safe, effective, and reliable operation of your electrocoating process, the selection and maintenance of the optimum unit for your operation is time well spent.  相似文献   
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Is homophobia associated with homosexual arousal?   总被引:1,自引:0,他引:1  
The authors investigated the role of homosexual arousal in exclusively heterosexual men who admitted negative affect toward homosexual individuals. Participants consisted of a group of homophobic men (n?=?35 ) and a group of nonhomophobic men (n?=?29); they were assigned to groups on the basis of their scores on the Index of Homophobia (W. W. Hudson & W. A. Ricketts, 1980). The men were exposed to sexually explicit erotic stimuli consisting of heterosexual, male homosexual, and lesbian videotapes, and changes in penile circumference were monitored. They also completed an Aggression Questionnaire (A. H. Buss & M. Perry, 1992). Both groups exhibited increases in penile circumference to the heterosexual and female homosexual videos. Only the homophobic men showed an increase in penile erection to male homosexual stimuli. The groups did not differ in aggression. Homophobia is apparently associated with homosexual arousal that the homophobic individual is either unaware of or denies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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Rationally, engineering a favorable physicochemical microenvironment for enzymes has recently emerged as an effective strategy to improve their catalytic performance. In this review, we discuss four microenvironmental effects according to the mechanism of action: localizing and excluding reactants and regulators, regulating microenvironmental pH, creating a water-like microenvironment, and increasing the local temperature. These mechanisms are enzyme-independent and can in principle be used in combination to tailor enzyme behaviors, offering new approaches to enabling, enhancing, and regulating enzyme catalysis in diverse applications without the need for genetic engineering.  相似文献   
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