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71.
D Mellière D Berrahal P Desgranges E Allaire JP Becquemin 《Canadian Metallurgical Quarterly》1998,23(5):342-348
The purpose of this study was to compare the physiological responses of professional and elite road cyclists during an incremental cycle ergometer test. Twenty-five elite cyclists (EC; 23+/-1 yr) and 25 professional cyclists (PC; 25+/-2yr) performed a ramp protocol (increases of 25 W x min(-1)) during which the following parameters were measured: oxygen consumption (VO2), pulmonary ventilation (VE), ventilatory equivalents for oxygen and carbon dioxide (VE x VO2(-1) and VE x VCO2(-1), respectively), respiratory exchange ratio (RER), ventilatory thresholds 1 and 2 (VT1 and VT2, respectively), blood lactate, and electromyographic activity (EMG) of the vastus lateralis. Significant differences existed between the two groups mainly at submaximal intensities, since both VT1 and VT2 occurred at a higher exercise intensity (p<0.001) in PC than in EC (VT2: 80.4+/-6.6 vs 87.0+/- 5.9% VO2max in EC and PC, respectively). Lactate levels showed a similar response in both groups at low-to-moderate intensities (< 300 W), and thereafter blood lactate was significantly higher in EC. Finally, the "electromyographic threshold" (EMGT) occurred at a significantly higher intensity (p < 0.05) in PC when compared to EC (64.7+/-14.2 vs 56.0+/-14.9% VO2max, respectively). It was concluded that, in comparison with EC, PC exhibit some remarkable physiological characteristics such as a high VT2, an important reliance on fat metabolism even at high power outputs, and several neuromuscular adaptations. 相似文献
72.
A Edmar A Lombès M Renouil A Bangui D Lamblin B Boumahni G Chaurand JB Mariette A Fourmaintraux L Vallee 《Canadian Metallurgical Quarterly》1998,5(9):1000-1003
BACKGROUND: MELAS syndrome is a rare mitochondrial cytopathy; its diagnosis can be difficult. CASE REPORT: A 6-month-old boy presented with febrile seizures, possibly due to viral meningitis. At 7 months, he developed myoclonia and "brain attacks" and, subsequently, myoclonical attacks, regression of psychomotor and mental acquisitions, and progressive visual loss. The ratio of lactatorachia/lactacidemia was increased. The molecular genetic analysis showed an heteroplasmic point mutation with A-to-G mutation at nucleotide 3243 of the mitochondrial tRNA(leu) (UUR) gene. He was the second child of a mother having frequent headaches. His great aunt, a sister of his maternal grandmother, was mentally retarded and had frequent epileptic seizures and hemiparesy since her childhood. CONCLUSION: Any unusual neurological symptom, particularly when combined with "illegitimate" symptoms, should lead to search for a mitochondrial cytopathy. 相似文献
73.
Szymanski TH Au A Lafrenière-Roula M Tyan V Supmonchai B Wong J Zerrouk B Obenaus ST 《Applied optics》1998,37(2):264-275
The design of a scalable optical local area network formultiprocessing systems is described. Each workstation has aparallel-fiber-ribbon optical link to a centralized complementarymetal-oxide silicon (CMOS) switch core, implemented on a singlecompact printed circuit board (PCB). When the Motorola Optobusfiber technology is used, each workstation has a data bandwidth of 6.4Gbits/s to the core. A centralized switch core interconnecting 32workstations supports a 204-Gbit/s aggregate data bandwidth. Theswitch core is based on a conventional broadcast-and-selectarchitecture, implemented with parallel CMOS integrated circuits(IC's). The switch core scales well; by incorporation of theCMOS optoelectronic IC's with optical input-output, the electricalcore can be reduced to a single-chip optoelectronic IC with terabitcapacities. A prototype of an optoelectronic switch core has been fabricated and is described. The appeal of the architectureincludes its reliance on commercially available parallel-fibertechnology, its reliance on the well-developed markets of local areanetworks and networks of workstations, and its smooth scalability from the electrical to optical domains as technology matures. 相似文献
74.
A method of multichannel processing to compute correlation products simultaneously is introduced. The signals that process are encoded on a single light beam through the use of an electro-optic modulators that induce optical delays greater than the coherence length of light. The coherence-modulated light beam thus obtained is then spatially and temporally modulated through an acousto-optic Bragg cell. The potential number of channels is estimated to be approximately 5-10. The method can be combined with other existing systems, such as time-, space-, or frequency-multiplexed correlators, to increase the channel number. The method also applies to high-resolution spectral analysis. 相似文献
75.
Bays R Wagnières G Robert D Braichotte D Savary JF Monnier P van den Bergh H 《Applied optics》1996,35(10):1756-1766
A noninvasive method to measure the optical properties of a diffusing and absorbing medium is described. Based on the spatially resolved measurement of diffuse reflectance at the sample surface, this method is particularly suitable for investigating the in vivo optical properties of biological tissues endoscopically in a clinical context. The sensitivity of the measurement is discussed, and two optical probes for two different clinical applications are presented. Preliminary measurements are performed on a nonbiological medium, which illustrate the possibilities of the proposed method. Finally, we report on in vivo measurements of the optical properties of the human esophageal wall at 630 nm. 相似文献
76.
77.
Mylène C. Q. Farias 《Journal of the Society for Information Display》2011,19(11):764-770
Abstract— In the past few years, a big effort in the scientific community has been devoted to the development of better image‐ and video‐quality metrics that correlate well with the human perception of quality. In this paper, an overview of the main ideas used in the design of objective quality metrics is given. More specifically, we briefly describe the different types of objective metrics and present a representative set of the different approaches taken by these algorithms. Finally, the challenges and recent developments in the area of image and video quality are discussed. 相似文献
78.
Véronique Souchère Laurent Millair Javier Echeverria François Bousquet Christophe Le Page Michel Etienne 《Environmental Modelling & Software》2010,25(11):1359-1370
Erosive runoff is a recurring problem and is a source of sometimes deadly muddy floods in the Pays de Caux (France). The risk results from a conjunction of natural factors and human activity. Efficient actions against runoff in agricultural watersheds are well known. However they are still difficult to implement as they require co-operation between stakeholders. Local actors thus need tools to help them understand the collective consequences of their individual decisions and help to initiate a process of negotiation between them. We decided to use a participatory approach called companion modelling (ComMod), and, in close collaboration with one of the first group of local stakeholders, to create a role-playing game (RPG) to facilitate negotiations on the future management of erosive runoff. This paper describes and discusses the development of the RPG and its use with other groups of local stakeholders within the framework of two game sessions organized by two different watershed management committees. During the joint construction step, stakeholders shared their viewpoints about the environment, agents, rules, and how to model runoff in preparation for the creation of the RPG. During the RPG sessions, two groups of eight players, including farmers, mayors and watershed advisors, were confronted with disastrous runoff in a fictive agricultural watershed. Results showed that they managed to reduce runoff by 20–50% by engaging a dialogue about grass strips, storage ponds and management of the intercrop period. However, further progress is still needed to better control runoff through the implementation of better agricultural practices because, during the RPG sessions, the watershed advisors did not encourage farmers to do so. Because of the complexity of management problems, results of jointly constructing the game and the RPG sessions showed that modelling and simulation can be a very useful way of accompanying the collective learning process. This new way of working was welcomed by the participants who expressed their interest in organizing further RPG sessions. 相似文献
79.
Roberto Sanchez Geneviève Dauphin-Tanguy Xavier Guillaud Frédéric Colas 《Simulation Modelling Practice and Theory》2010,18(9):1185-1198
This paper proposes a model of a three phase electrical inverter with a LC output filter in delta connection used in a renewable energy supply system. The concept of inverse bond graph via bicausality is used for the control law design. The control law robustness is tested by connecting passive and active (induction machine) loads. 相似文献
80.
We explore one aspect of the structure of a codified legal system at the national level using a new type of representation
to understand the strong or weak dependencies between the various fields of law. In Part I of this study, we analyze the graph
associated with the network in which each French legal code is a vertex and an edge is produced between two vertices when
a code cites another code at least one time. We show that this network distinguishes from many other real networks from a
high density, giving it a particular structure that we call concentrated world and that differentiates a national legal system (as considered with a resolution at the code level) from small-world graphs identified in many social networks. Our analysis then shows that a few communities (groups of highly wired vertices)
of codes covering large domains of regulation are structuring the whole system. Indeed we mainly find a central group of influent
codes, a group of codes related to social issues and a group of codes dealing with territories and natural resources. The
study of this codified legal system is also of interest in the field of the analysis of real networks. In particular we examine
the impact of the high density on the structural characteristics of the graph and on the ways communities are searched for.
Finally we provide an original visualization of this graph on an hemicyle-like plot, this representation being based on a
statistical reduction of dissimilarity measures between vertices. In Part II (a following paper) we show how the consideration
of the weights attributed to each edge in the network in proportion to the number of citations between two vertices (codes)
allows deepening the analysis of the French legal system. 相似文献