Theory of bending,torsion and buckling of thin-walled members of open cross section     

Stephen P. Timoshenko 《Journal of The Franklin Institute》1945,239(4):249-268

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Validity Issues in Test Speededness     

Ying Lu  Stephen G. Sireci 《Educational Measurement》2007,26(4):29-37

Speededness refers to the situation where the time limits on a standardized test do not allow substantial numbers of examinees to fully consider all test items. When tests are not intended to measure speed of responding, speededness introduces a severe threat to the validity of interpretations based on test scores. In this article, we describe test speededness, its potential threats to validity, and traditional and modern methods that can be used to assess the presence of speededness. We argue that more attention must be paid to this issue and that more research must be done to set appropriate time limits on power tests so that speed of responding does not interfere with the construct measured.  相似文献   

Physics and engineering of high power switching devices : Thomas H. Lee. 542 pages,diagrams, 6x9 in., MIT Press,Cambridge, Mass., 1975. Price, $25.00.     

Stephen A. Sebo 《Journal of The Franklin Institute》1978,306(5):375-376

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The Invisible Majority: Adult Learners in English Higher Education     

Stephen McNair 《Higher Education Quarterly》1998,52(2):162-178

The report of the National Inquiry into Higher Education (the Dearing Committee) makes much play of lifelong learning, and the last decade has seen a rapid increase in the proportion of mature learners in higher education overall. In 1993 the National Institute for Adult Continuing Education argued that the advent of lifelong learning and an adult majority in higher education called for a radical rethinking of the nature and purposes of higher education. There has been some positive change, and the Dearing report is broadly positive, but by failing to recognise the nature of the lifelong agenda, it may be too little too late.  相似文献   

Toward a reconstitution of academic governance     

Stephen H. Balch 《Academic Questions》2004,17(1):67-72

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Rethinking fat as a fuel for endurance exercise     

Jeff S. Volek  Timothy Noakes  Stephen D. Phinney 《European Journal of Sport Science》2015,15(1):13-20

Abstract

A key element contributing to deteriorating exercise capacity during physically demanding sport appears to be reduced carbohydrate availability coupled with an inability to effectively utilize alternative lipid fuel sources. Paradoxically, cognitive and physical decline associated with glycogen depletion occurs in the presence of an over-abundance of fuel stored as body fat that the athlete is apparently unable to access effectively. Current fuelling tactics that emphasize high-carbohydrate intakes before and during exercise inhibit fat utilization. The most efficient approach to accelerate the body’s ability to oxidize fat is to lower dietary carbohydrate intake to a level that results in nutritional ketosis (i.e., circulating ketone levels >0.5 mmol/L) while increasing fat intake for a period of several weeks. The coordinated set of metabolic adaptations that ensures proper interorgan fuel supply in the face of low-carbohydrate availability is referred to as keto-adaptation. Beyond simply providing a stable source of fuel for the brain, the major circulating ketone body, beta-hydroxybutyrate, has recently been shown to act as a signalling molecule capable of altering gene expression, eliciting complementary effects of keto-adaptation that could extend human physical and mental performance beyond current expectation. In this paper, we review these new findings and propose that the shift to fatty acids and ketones as primary fuels when dietary carbohydrate is restricted could be of benefit for some athletes.  相似文献   

TV and the iPad: How the Tablet is Redefining the Way We Watch     

Stephen P. McCreery  Dean M. Krugman 《广播与电子媒介杂志》2015,59(4):620-639

The tablet computer offers options for streaming TV programming that potentially alters viewing behaviors compared to the traditional television set, yet there is a dearth of research related to this viewing alternative. This study uses a national sample of adult iPad owners to investigate the tablet's role as a TV. The frameworks of continuity-discontinuity, use-diffusion, and attention and absorption to programming are applied to uncover where the tablet fits into the current repertoire of viewing devices, and how individuals are engaging with traditional TV programming through it. Results show that overall, the tablet's functionality as a TV can lead to experiential differences.  相似文献   

The Unbearable Insecurity of the Electronic Resources Librarian     

Stephen Buck 《期刊图书馆员》2015,68(1-4):106-116

The article will outline the Core Competencies for Electronic Resources Librarians (NASIG Core Competencies Task Force [July 2013]) and intersect them with the practical everyday working experiences of an e-resources and periodicals librarian. The aim of the article is to convey an understanding of working in a practical library office environment, while being aware of the complexity of the theoretical competencies that are desirable and recommended. While it is aimed mainly at librarians, it should also be of interest to publishers and other vendors as they gain an understanding of what it is that librarians (their customers) do all day.  相似文献   

Thermally multiplexed polymerase chain reaction     

Christopher R. Phaneuf  Nikita Pak  D. Curtis Saunders  Gregory L. Holst  Joav Birjiniuk  Nikita Nagpal  Stephen Culpepper  Emily Popler  Andi L. Shane  Robert Jerris  Craig R. Forest 《Biomicrofluidics》2015,9(4)

Amplification of multiple unique genetic targets using the polymerase chain reaction (PCR) is commonly required in molecular biology laboratories. Such reactions are typically performed either serially or by multiplex PCR. Serial reactions are time consuming, and multiplex PCR, while powerful and widely used, can be prone to amplification bias, PCR drift, and primer-primer interactions. We present a new thermocycling method, termed thermal multiplexing, in which a single heat source is uniformly distributed and selectively modulated for independent temperature control of an array of PCR reactions. Thermal multiplexing allows amplification of multiple targets simultaneously—each reaction segregated and performed at optimal conditions. We demonstrate the method using a microfluidic system consisting of an infrared laser thermocycler, a polymer microchip featuring 1 μl, oil-encapsulated reactions, and closed-loop pulse-width modulation control. Heat transfer modeling is used to characterize thermal performance limitations of the system. We validate the model and perform two reactions simultaneously with widely varying annealing temperatures (48 °C and 68 °C), demonstrating excellent amplification. In addition, to demonstrate microfluidic infrared PCR using clinical specimens, we successfully amplified and detected both influenza A and B from human nasopharyngeal swabs. Thermal multiplexing is scalable and applicable to challenges such as pathogen detection where patients presenting non-specific symptoms need to be efficiently screened across a viral or bacterial panel.  相似文献   

The effect of l-citrulline and watermelon juice supplementation on anaerobic and aerobic exercise performance     

Paul T. Cutrufello  Stephen J. Gadomski  Gerald S. Zavorsky 《Journal of sports sciences》2015,33(14):1459-1466

Citrulline has been proposed as an ergogenic aid, leading to an interest in watermelon given its high citrulline concentration. The aim of this study was to determine the effects of a single, pre-exercise dose of l-citrulline, watermelon juice, or a placebo on the total maximum number of repetitions completed over 5 sets, time to exhaustion, maximal oxygen consumption (VO₂max), anaerobic threshold, and flow-mediated vasodilation. A randomised double-blind within-participants study design was used to examine these effects among 22 participants (n = 11 males). Supplementation included either a 7.5% sucrose drink containing 6 g of l-citrulline, 710 mL of watermelon juice (~1.0 g citrulline), or a 7.5% sucrose placebo drink. Supplementation was administered 1 or 2 h before exercise testing to investigate a timing effect. There was no significant effect between the three supplements for the total number of repetitions, time to exhaustion, VO₂max, anaerobic threshold, or flow-mediated vasodilation. There was also no interaction observed relative to gender or supplement timing (P > 0.05). A single dose of l-citrulline or watermelon juice as a pre-exercise supplement appears to be ineffective in improving exercise performance; however, greater doses of l-citrulline have been shown to be safe and are currently left unexamined.  相似文献