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S Merino A Aguilar JM Tomás R Bonet MJ Martinez D Simón-Pujol F Congregado 《Canadian Metallurgical Quarterly》1997,22(5):315-320
1. We investigated the effect of exercise on plasma adrenomedullin, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations and studied the relationship between these peptides and haemodynamic parameters in nine patients with old myocardial infarction (MI) and in eight normal subjects. 2. The exercise protocol consisted of two fixed work loads (40 and 80 W) for 4 min each and venous blood samples were taken at rest, during each exercise stage and after exercise while monitoring the mean arterial pressure (MAP) and heart rate (HR). In MI, pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), left ventricular end-diastolic pressure (LVEDP) and cardiac output (CO) were measured throughout exercise. 3. Adrenomedullin levels did not significantly increase with exercise. Adrenomedullin levels correlated with PAP and PCWP at rest (P < 0.05). Atrial natriuretic peptide levels correlated with PAP, PCWP and LVEDP throughout exercise (P < 0.05) but, on multiple regression analysis, PCWP correlated only with ANP (P < 0.01). Brain natriuretic peptide levels correlated with LVEDP throughout exercise (P < 0.01) and its increment correlated closely with basal BNP levels at rest (P < 0.01). 4. These results suggest that adrenomedullin does not respond to the acute haemodynamic changes of exercise, whereas ANP responds to it and PCWP is the major stimulus factor. Brain natriuretic peptide responds to exercise in proportion to the basal synthesis of BNP in patients with left ventricular dysfunction and LVEDP may play a role in increasing BNP during exercise. 相似文献
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Constructing inferences during narrative text comprehension. 总被引:1,自引:0,他引:1
Describes a constructionist theory that accounts for the knowledge-based inferences that are constructed when readers comprehend narrative text. Readers potentially generate a rich variety of inferences when they construct a referential situation model of what the text is about. The proposed constructionist theory specifies that some, but not all, of this information is constructed under most conditions of comprehension. The distinctive assumptions of the constructionist theory embrace a principle of search (or effort) after meaning. According to this principle, readers attempt to construct a meaning representation that addresses the reader's goals, that is coherent at both local and global levels, and that explains why actions, events, and states are mentioned in the text. This study reviews empirical evidence that addresses this theory and contrasts it with alternative theoretical frameworks. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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A survey of CSCW systems 总被引:4,自引:0,他引:4
Tom Rodden 《Interacting with computers》1991,3(3):319-353
Over the last decade, computer supported cooperative work (CSCW) has emerged as an identifiable research area that focuses on the role of the computer in group work. CSCW is a generic term which combines the understanding of the nature of group working with the enabling technologies of computer networking, systems support and applications. The paper examines the classes of system which have emerged to support cooperative working. A framework for characterising and describing CSCW systems is presented and four major classes of cooperative system identified. Each of these classes of cooperative system are examined highlighting their general characteristics and applicability to CSCW. 相似文献
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Tom Verhoeff 《Distributed Computing》1988,3(1):1-8
The problem of delay-insensitive data communication is described. The notion of delay-insensitive code is defined, giving precise conditions under which delay-insensitive data communication is feasible. Examples of these codes are presented and analyzed. It appears that delay-insensitive codes are equivalent with antichains in partially ordered sets and with all unidirectional error-detecting codes.
Tom Verhoeff received the B.S. and M.S. degrees in mathematics from Eindhoven University of Technology, The Netherlands, in 1985. He is currently an Assistant Professor at the Department of Mathematics and Computing Science of the same university. His main research interests are parallel computations, especially formalisms for their specification and design, and their implementation as delay-insensitive VLSI circuits. 相似文献
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Tom Carter 《Urban Policy and Research》2005,23(3):265-286
Current demographic trends in Canada include population aging and declining household growth. These trends generally result in falling housing demand and stable or declining house prices. Housing markets in Canada's major cities, however, have been characterized by increases in demand and prices in recent years; due in large part to the influence of arriving immigrants. The destinations of 76 percent of international immigrants to Canada are the three global cities—Toronto, Vancouver and Montreal—where they have a very significant effect on housing demand, particularly as under current immigration policy many of those arriving come with considerable wealth. Their influence, however, is much broader and includes the growth of exclusive, prosperous immigrant neighbourhoods, new architectural designs and other neighbourhood changes. Not all immigrants, however, arrive with wealth. Many are poor, live in less attractive neighbourhoods and pay unrealistic amounts of their inadequate incomes for poor quality housing. Some end up homeless on the street. The role of immigrants in housing markets is an important consideration for urban and housing policy. 相似文献
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Tom Fitzpatrick 《电子测试》2005,(11):34-42
虽然目前的IC设计持续以惊人的速度复杂化,但设计者仍然希望可以通过先进的验证工作提高工作效率.所谓的先进验证工作便是将测试平台自动化(Test-Bench Automation)和正式属性检测(Formal Property Checking)两功能添加到功能验证(Functional Verification)的流程之中.本文将主要探讨其中的基本概念、价值以及使用方法,进而帮助读者了解. 相似文献