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Speed
Kinds of Speed Terms modified by Speed Selected AbstractsMEASUREMENT OF THE NATURAL FREQUENCIES AND CRITICAL SPEED OF ROLL-TENSIONED DISCSEXPERIMENTAL TECHNIQUES, Issue 4 2000E. Aubry First page of article [source] Accelerating non-contrast-enhanced MR angiography with inflow inversion recovery imaging by skipped phase encoding and edge deghosting (SPEED)JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2010Zheng Chang PhD Abstract Purpose: To accelerate non-contrast-enhanced MR angiography (MRA) with inflow inversion recovery (IFIR) with a fast imaging method, Skipped Phase Encoding and Edge Deghosting (SPEED). Materials and Methods: IFIR imaging uses a preparatory inversion pulse to reduce signals from static tissue, while leaving inflow arterial blood unaffected, resulting in sparse arterial vasculature on modest tissue background. By taking advantage of vascular sparsity, SPEED can be simplified with a single-layer model to achieve higher efficiency in both scan time reduction and image reconstruction. SPEED can also make use of information available in multiple coils for further acceleration. The techniques are demonstrated with a three-dimensional renal non-contrast-enhanced IFIR MRA study. Results: Images are reconstructed by SPEED based on a single-layer model to achieve an undersampling factor of up to 2.5 using one skipped phase encoding direction. By making use of information available in multiple coils, SPEED can achieve an undersampling factor of up to 8.3 with four receiver coils. The reconstructed images generally have comparable quality as that of the reference images reconstructed from full k -space data. Conclusion: As demonstrated with a three-dimensional renal IFIR scan, SPEED based on a single-layer model is able to reduce scan time further and achieve higher computational efficiency than the original SPEED. J. Magn. Reson. Imaging 2010;31:757,765. © 2010 Wiley-Liss, Inc. [source] SPEED: single-point evaluation of the evolution dimensionMAGNETIC RESONANCE IN CHEMISTRY, Issue 9 2007Eriks Kup Abstract Two-dimensional NMR spectroscopy can be speeded up by orders of magnitude by severely restricting the number of sampling operations in the evolution dimension,we demonstrate that just a single measurement may suffice. The frequencies evolving in the indirect dimension (t1) are deduced from the amplitudes of the signals acquired in the direct dimension (t2). Prior measurements of the one-dimensional spectra are required. Results are presented for the two-dimensional 13C-HSQC spectrum of 2-ethylindanone recorded at a single fixed setting of the evolution time, demonstrating a speed advantage of 120. The method can be extended to multidimensional spectra, with correspondingly greater gains in speed. Copyright © 2007 John Wiley & Sons, Ltd. [source] TIME MATTERS IN TEAM PERFORMANCE: EFFECTS OF MEMBER FAMILIARITY, ENTRAINMENT, AND TASK DISCONTINUITY ON SPEED AND QUALITYPERSONNEL PSYCHOLOGY, Issue 3 2003DAVID A. HARRISON We compared the speed and quality of performance for familiar, initially unfamiliar but continuing, and one-shot (single session) teams. We also proposed and observed entrainment effects for task time limits. Over the course of weekly sessions with changing tasks, continuing teams reached speed levels of the initially familiar teams, but the one-shot teams were consistently slower. Continuing teams also tended to have higher-quality output than the one-shot teams. There were no differences in how quickly each type of group entrained to time limits on the tasks. Entrainment was not robust to task discontinuity (Task A, then B). However, entrainment on repeated trials of a task persisted even when a different type of task "interrupted" those repeated trials (Task A, then B, then A again). Results compel a richer incorporation of time as a medium for complex task sequences, and time-based constructs as a feature of team membership in the study of group effectiveness. [source] SWIMMING SPEEDS OF SINGING AND NON-SINGING HUMPBACK WHALES DURING MIGRATIONMARINE MAMMAL SCIENCE, Issue 3 2007Michael J. Noad Abstract Limited data exist on swimming speeds of humpback whales (Megaptera novaeangliae) and none on swimming speeds of singing whales during migration. We tracked humpback whales visually and acoustically during migration from the breeding grounds past our study site on the east coast of Australia (latitude 26°28,S). The mean swimming speed for whales while singing was 2.5 km/h, significantly less than for non-singing whales with a mean of 4.0 km/h but significantly greater than the mean of 1.6 km/h observed for singing whales on the Hawaiian breeding grounds. Between song sessions, there was no significant difference in speeds between whales that had been singing and other whales. Migration speeds were less for whales while singing but increased during the season. Although humpback whales can swim rapidly while singing (maximum observed 15.6 km/h), they generally do not do so, even during migration. Slower migration by singers would delay their return to the polar feeding areas and may be costly, but may be a strategy to provide access to more females. [source] Fast Volume Rendering and Data Classification Using Multiresolution in Min-Max OctreesCOMPUTER GRAPHICS FORUM, Issue 3 2000Feng Dong Large-sized volume datasets have recently become commonplace and users are now demanding that volume-rendering techniques to visualise such data provide acceptable results on relatively modest computing platforms. The widespread use of the Internet for the transmission and/or rendering of volume data is also exerting increasing demands on software providers. Multiresolution can address these issues in an elegant way. One of the fastest volume-rendering alrogithms is that proposed by Lacroute & Levoy 1 , which is based on shear-warp factorisation and min-max octrees (MMOs). Unfortunately, since an MMO captures only a single resolution of a volume dataset, this method is unsuitable for rendering datasets in a multiresolution form. This paper adapts the above algorithm to multiresolution volume rendering to enable near-real-time interaction to take place on a standard PC. It also permits the user to modify classification functions and/or resolution during rendering with no significant loss of rendering speed. A newly-developed data structure based on the MMO is employed, the multiresolution min-max octree, M 3 O, which captures the spatial coherence for datasets at all resolutions. Speed is enhanced by the use of multiresolution opacity transfer functions for rapidly determining and discarding transparent dataset regions. Some experimental results on sample volume datasets are presented. [source] Speed, States, and Social Theory: A Response to Hartmut RosaCONSTELLATIONS: AN INTERNATIONAL JOURNAL OF CRITICAL AND DEMOCRATIC THEORY, Issue 1 2003William E. Scheuerman First page of article [source] Monitoring dyslexics' intelligence and attainments: A follow-up studyDYSLEXIA, Issue 1 2003Michael Thomson Abstract Intelligence (Wechsler Intelligence Scale for Children R and III, 1992) and written language attainment (BAS Word Reading, Neale Analysis of Reading, Vernon Graded Word Spelling) data for around 250 children attending a specialist school for dyslexics are presented. The Wechsler scales data show some evidence for ,ACID' and ,SCAD' profile effects on the subtests, with specifically weak Index scores on Freedom from Distractibility and Processing Speed. The relationship between intelligence and reading development is also examined, with evidence for significant correlations between intelligence and written language and a longitudinal study showing that there is no ,Matthew' or drop-off effect in intelligence. The attainments tests demonstrate that the widening gap between a dyslexic's chronological age and his/her attainments can be closed, and how attainments may be monitored within the context of ,growth curves'. The results are discussed in relation to recent reports (e.g. B.P.S. on Dyslexia, Literacy and Psychological Assessment) on the relationship between intelligence and attainments and it is concluded that this report could be seriously misleading for practising educational psychologists. Copyright © 2003 John Wiley & Sons, Ltd. [source] Differences in the Rapid Knockdown and Lethal Effects of Aerosol Formulations against German Cockroach (Blattaria, Blattellidae) StrainsENTOMOLOGICAL RESEARCH, Issue 4 2002Dong-Kyu LEE ABSTRACT The knockdown and lethal efficacies of five aerosol formulations including Combat Speed® (AIs: 0.1 % imiprothrin and 0.3% cyphenothrin), Raid Power® (AIs: 1.0% pyrethrin and 0.2% permethrin), Home Keeper®, (AIs: 0.2% tetramethrin and 0.3% permethrin), Super Killer® (AIs: 0.32% tetramethrin and 0.08% bioresmethrin), and Perma Kill-K® (AIs: 0.3% dichlorvos and 0.1% tetramethrin) against five strains of the German cockroach, Blattella germanica (L.) were assessed. The results show that the mean value of KT50 (5.4 sec.) of Combat Speed® was 4.5 and 3.1-folds lower than those of Perma Kill-K® and Home Keeper®, respectively. The mean value of KT90 (9.0 sec; slope = 10.02) of Combat Speed® was 3.8 to 5.8-folds lower than Perma Kill-K®, Supper Killer® and Home Keeper®. As lethal effects, the mean value of LT50 (17.3 sec.) of Combat Speed® was over 26 folds lower than Supper Killer® and Perma Kill-K®. The mean value of LT90 (32.9 sec.) of Combat Speed® was 37.4 and 15.1-folds lower than those of Supper Killer® and Perma Kill-K®, respectively. In general, Combat Speed® and Raid Power® were considered the insecticide aerosols with faster knockdown and higher lethal effects than Supper Killer®, Perma Kill-K®, and Home Keeper® against five strains of German cockroaches in Korea. Also, the knockdown and lethal effects of Supper Killer®, Perma Kill-K®, and Home Keeper® were highly variable depends on the strains. [source] Defining International Entrepreneurship and Modeling the Speed of Internationalization,ENTREPRENEURSHIP THEORY AND PRACTICE, Issue 5 2005Benjamin M. Oviatt This article provides a reformulated definition of international entrepreneurship. Consistent with the new definition, a model is presented of how the speed of entrepreneurial internationalization is influenced by various forces. The model begins with an entrepreneurial opportunity and depicts the enabling forces of technology, the motivating forces of competition, the mediating perceptions of entrepreneurs, and the moderating forces of knowledge and networks that collectively determine the speed of internationalization. [source] The effect of training on stride parameters in a cohort of National Hunt racing Thoroughbreds: A preliminary studyEQUINE VETERINARY JOURNAL, Issue 5 2009M. FERRARI Summary Reasons for performing study: The influence of training on stride parameters is controversial and to date there is no information on how training influences stride parameters during high-speed locomotion in the field. Objective: To determine the influence of training on stride variables during high-speed locomotion in Thoroughbred racehorses. Methods: Speed, stride frequency, stance and protraction times were quantified in 8 Thoroughbreds with foot mounted accelerometers and GPS sensors during their first week of canter after the summer break and 6 months into training. Results: At a speed of 11 m/s, stride frequency was (mean ± s.d.) 2.160 ± 0.120 strides/s pre- and 2.167 ± 0.083 strides/s post training; mean stance time was 125.3 ± 9 ms pre- and 125.9 ± 7 ms post training; protraction time was 340.7 ± 20.4 ms pre- and 337.2 ± 14.3 ms post training. The increase in stride frequency and the decrease in protraction time after training were significant. There was no statistically significant difference in the maximum speed reached by each horse pre- and post training. Conclusions: Stance time stayed constant throughout the training season in the tested horses. A significant decrease in protraction time and a corresponding significant increase in stride frequency were observed after training. Potential relevance: Training of racehorses could be adapted to maximise the effect on modifiable parameters and reduce the risk of training-induced pathologies. Further research will be conducted to investigate the effect of different training protocols on a large number of horses. [source] Sex, Reproductive Status, and Cost of Tail Autotomy via Decreased Running Speed in LizardsETHOLOGY, Issue 1 2009William E. Cooper Jr Autotomy, voluntary shedding of body parts to permit escape, is a theoretically interesting defense because escape benefit is offset by numerous costs, including impaired future escape ability. Reduced sprint speed is a major escape cost in some lizards. We predicted that tail loss causes decreased speed in males and previtellogenic females, but not vitellogenic females already slowed by mass gain. In the striped plateau lizard, Sceloporus virgatus, adults of both sexes are subject to autotomy, and females undergo large increases in body condition (mass/length) during vitellogenesis. Time required for running 1 m was similar in intact autotomized males and previtellogenic females, but increased by nearly half after autotomy. Vitellogenic females were slower than other lizards when intact, but their speed was unaffected by autotomy. Following autotomy, speeds of all groups were similar. Thus, speed costs of autotomy vary with sex and reproductive condition: decreased running speed is not a cost of autotomy in vitellogenic females or presumably gravid females. Costs of autotomy are more complex than previously known. Speed and other costs might interact in unforseen ways, making it difficult to predict whether strategies to compensate for diminished escape ability differ with reproductive condition in females. [source] A New Model of Light-Powered Chiral Molecular Motor with Higher Speed of Rotation, Part 1 , Synthesis and Absolute StereostructureEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2005Takuma Fujita Abstract To develop a molecular motor with a higher speed of rotation, a new model light-powered chiral molecular motor 2 of five-membered ring type was designed, and the motor rotation isomers (,)- 2a and (,)- 2c were directly synthesized in enantiopure forms for the first time from the ketone (+)- 8. The precursor alcohols 9 and 10 were enantioresolved by the camphorsultam-dichlorophthalic acid (CSDP acid; 3) method, and their absolute configurations were determined by X-ray crystallographic analysis of the CSDP ester (,)- 11b and chemical correlations. The enantiopure ketone (S)-(+)- 8 formed from (1S,2S)-(+)- 9 or (1R,2S)-(,)- 10 was subjected to the McMurry reaction with TiCl3/LiAlH4, yielding the motor rotation isomers [CD(,)257.8]-(2S,2,S)-(M,M)-(E)-(,)- 2a and [CD(,)270.0]-(2S,2,S)-(M,M)-(Z)-(,)- 2c. These studies enabled us unambiguously to determine the absolute stereostructure of the motor 2, which is of critical importance for control over the direction of motor rotation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Waveform distortion caused by high power adjustable speed drives part I: High computational efficiency modelsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2003F. De Rosa Waveform distortion caused by high power adjustable speed drives is considered and two high computational efficiency models are proposed. Both models are essentially based on the switching function theory and on a new simplified control system representation. The first refers to the solution based on the Line Commutated Inverters, the second to the case of the Pulse Width Modulated Inverters. Models' accuracy and computational efficiency are demonstrated. In a companion paper, the proposed models are applied inside a simulation procedure for the probabilistic analysis of waveform distortion on both the supply and motor sides of the two types of Adjustable Speed Drives here considered. [source] Plasticity of human skeletal muscle: gene expression to in vivo functionEXPERIMENTAL PHYSIOLOGY, Issue 5 2007Stephen D. R. Harridge Human skeletal muscle is a highly heterogeneous tissue, able to adapt to the different challenges that may be placed upon it. When overloaded, a muscle adapts by increasing its size and strength through satellite-cell-mediated mechanisms, whereby protein synthesis is increased and new nuclei are added to maintain the myonuclear domain. This process is regulated by an array of mechanical, hormonal and nutritional signals. Growth factors, such as insulin-like growth factor I (IGF-I) and testosterone, are potent anabolic agents, whilst myostatin acts as a negative regulator of muscle mass. Insulin-like growth factor I is unique in being able to stimulate both the proliferation and the differentiation of satellite cells and works as part of an important local repair and adaptive mechanism. Speed of movement, as characterized by maximal velocity of shortening (Vmax), is regulated primarily by the isoform of myosin heavy chain (MHC) contained within a muscle fibre. Human fibres can express three MHCs: MHC-I, -IIa and -IIx, in order of increasing Vmax and maximal power output. Training studies suggest that there is a subtle interplay between the MHC-IIa and -IIx isoforms, with the latter being downregulated by activity and upregulated by inactivity. However, switching between the two main isoforms appears to require significant challenges to a muscle. Upregulation of fast gene programs is caused by prolonged disuse, whilst upregulation of slow gene programs appears to require significant and prolonged activity. The potential mechanisms by which alterations in muscle composition are mediated are discussed. The implications in terms of contractile function of altering muscle phenotype are discussed from the single fibre to the whole muscle level. [source] Affected-sib-pair test for linkage based on constraints for identical-by-descent distributions corresponding to disease models with imprinting,GENETIC EPIDEMIOLOGY, Issue 4 2004Michael Knapp Abstract Holmans' possible triangle test for affected sib pairs has proven to be a powerful tool for linkage analysis. This test is a likelihood-ratio test for which maximization is restricted to the set of possible sharing probabilities. Here, we extend the possible triangle test to take into account genomic imprinting, which is also known as parent-of-origin effect. While the classical test without imprinting looks at whether affected sib pairs share 0, 1, or 2 alleles identical-by-descent, the likelihood-ratio test allowing for imprinting further distinguishes whether the sharing of exactly one allele is through the father or mother. Thus, if the disease gene is indeed subject to imprinting, the extended test presented here can take into account that affecteds will have inherited the mutant allele preferentially from one particular parent. We calculate the sharing probabilities at a marker locus linked to a disease susceptibility locus. Using our formulation, the constraints on these probabilities given by Dudoit and Speed ([1999] Statistics in Genetics; New York: Springer) can easily be verified. Next, we derive the asymptotic distribution of the restricted likelihood-ratio test statistic under the null hypothesis of no linkage, and give LOD-score criteria for various test sizes. We show, for various disease models, that the test allowing for imprinting has significantly higher power to detect linkage if imprinting is indeed present, at the cost of only a small reduction in power in case of no imprinting. Altogether, unlike many methods currently available, our novel model-free sib-pair test adequately models the epigenetic parent-of-origin effect, and will hopefully prove to be a useful tool for the genetic mapping of complex traits. © 2004 Wiley-Liss, Inc. [source] Power and robustness of a score test for linkage analysis of quantitative traits using identity by descent data on sib pairsGENETIC EPIDEMIOLOGY, Issue 4 2001Darlene R. Goldstein Abstract Identification of genes involved in complex traits by traditional (lod score) linkage analysis is difficult due to many complicating factors. An unfortunate drawback of non-parametric procedures in general, though, is their low power to detect genetic effects. Recently, Dudoit and Speed [2000] proposed using a (likelihood-based) score test for detecting linkage with IBD data on sib pairs. This method uses the likelihood for ,, the recombination fraction between a trait locus and a marker locus, conditional on the phenotypes of the two sibs to test the null hypothesis of no linkage (, = ½). Although a genetic model must be specified, the approach offers several advantages. This paper presents results of simulation studies characterizing the power and robustness properties of this score test for linkage, and compares the power of the test to the Haseman-Elston and modified Haseman-Elston tests. The score test is seen to have impressively high power across a broad range of true and assumed models, particularly under multiple ascertainment. Assuming an additive model with a moderate allele frequency, in the range of p = 0.2 to 0.5, along with heritability H = 0.3 and a moderate residual correlation , = 0.2 resulted in a very good overall performance across a wide range of trait-generating models. Generally, our results indicate that this score test for linkage offers a high degree of protection against wrong assumptions due to its strong robustness when used with the recommended additive model. Genet. Epidemiol. 20:415,431, 2001. © 2001 Wiley-Liss, Inc. [source] Effects of lorazepam on visual perceptual abilitiesHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 3 2008S. Pompéia Abstract Objective To evaluate the effects of an acute dose of the benzodiazepine (BZ) lorazepam in young healthy volunteers on five distinguishable visual perception abilities determined by previous factor-analytic studies. Methods This was a double-blind, cross-over design study of acute oral doses of lorazepam (2,mg) and placebo in young healthy volunteers. We focused on a set of paper-and-pencil tests of visual perceptual abilities that load on five correlated but distinguishable factors (Spatial Visualization, Spatial Relations, Perceptual Speed, Closure Speed, and Closure Flexibility). Some other tests (DSST, immediate and delayed recall of prose; measures of subjective mood alterations) were used to control for the classic BZ-induced effects. Results Lorazepam impaired performance in the DSST and delayed recall of prose, increased subjective sedation and impaired tasks of all abilities except Spatial Visualization and Closure Speed. Only impairment in Perceptual Speed (Identical Pictures task) and delayed recall of prose were not explained by sedation. Conclusion Acute administration of lorazepam, in a dose that impaired episodic memory, selectively affected different visual perceptual abilities before and after controlling for sedation. Central executive demands and sedation did not account for results, so impairment in the Identical Pictures task may be attributed to lorazepam's visual processing alterations. Copyright © 2008 John Wiley & Sons, Ltd. [source] Energy Saving Speed and Charge/Discharge Control of a Railway Vehicle with On-board Energy Storage by Means of an Optimization ModelIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2009Masafumi Miyatake Member Abstract The optimal operation of rail vehicle minimizing total energy consumption is discussed in this paper. In recent years, the energy storage devices have enough energy and power density to use in trains as on-board energy storage. The on-board storage can assist the acceleration/deceleration of the train and may decrease energy consumption. Many works on the application of the energy storage devices to trains were reported, however, they did not deal enough with the optimality of the control of the devices. The authors pointed out that the charging/discharging command and vehicle speed profile should be optimized together based on the optimality analysis. The authors have developed the mathematical model based on a general optimization technique, sequential quadratic programming. The proposed method can determine the optimal acceleration/deceleration and current commands at every sampling point under fixed conditions of transfer time and distance. Using the proposed method, simulations were implemented in some cases. The electric double layer capacitor (EDLC) is assumed as an energy storage device in our study, because of its high power density etc. The trend of optimal solutions such as values of control inputs and energy consumption is finally discussed. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] The European Employment Strategy From Amsterdam to Stockholm: Has it Reached its Cruising Speed?INDUSTRIAL RELATIONS JOURNAL, Issue 5 2001Janine Goetschy First page of article [source] Speed of Processing and Face Recognition at 7 and 12 MonthsINFANCY, Issue 4 2002Susan A. Rose This research examined developmental and individual differences in infants' speed of processing faces and the relation of processing speed to the type of information encoded. To gauge processing speed, 7- and 12-month-olds were repeatedly presented with the same face (frontal view), each time paired with a new one, until they showed a consistent preference for the new one. Subsequent probe trials assessed recognition of targets that either preserved configural integrity (Study 1: 3/4 profile and full profile poses) or disrupted it while preserving featural information (Study 2: rotations of 160° or 200° and fracturings). There were developmental differences in both speed and in infants' appreciation of information about faces. Older infants took about 60% fewer trials to reach criterion and had more mature patterns of attention (i.e., looks of shorter duration and more shifts of gaze). Whereas infants of both ages recognized the familiar face in a 3/4 pose, the 12-month-olds also recognized it in profile and when rotated. Twelve-month-olds who were fast processors additionally recognized the fractured faces; otherwise, processing speed was unrelated to the type of information extracted. At 7 months then, infants made use of some configural information in processing faces; at 12 months, they made use of even more of the configural information, along with part-based or featural information. [source] Face tracking for model-based coding and face animationINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2003Jörgen Ahlberg Abstract We present a face and facial feature tracking system able to extract animation parameters describing the motion and articulation of a human face in real-time on consumer hardware. The system is based on a statistical model of face appearance and a search algorithm for adapting the model to an image. Speed and robustness is discussed, and the system evaluated in terms of accuracy. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13: 8,22, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10042 [source] More Haste, Less Speed in Theology,INTERNATIONAL JOURNAL OF SYSTEMATIC THEOLOGY, Issue 3 2007JEAN-YVES LACOSTE Theological language lives urgently, under kerygmatic constraints, and yet is allowed delay for its tasks of interpretation. It searches for its words, forging a third language, which ,fulfils' the language of Jew and Greek and yet is a ,hard' language, tying the future of mankind to the fate of a single crucified man. It awakens a capacity for experience that is latent in us, yet violates our expectations. Hermeneutic demands take a new turn when speech becomes text. Languages age and die, but the meaning of their words does not. The world of past languages can be understood. The theologian is a translator, allowing the text to speak. Reading is preliminary to kerygmatic speech, and theology moves between the words of scripture and the words of immediate experience. The successful interpretation does not substitute itself for what it interprets, but makes us at home in the words and experience of the text. We learn it not as a mother-tongue but as a foreign language, and we discover that it is habitable. In introducing us to a universal reality mediated by that particular world, theology reveals us to ourselves, showing us that our continuity with it is stronger than any discontinuity. Theology must have its ,method', which is to acquire its own language by way of a detour through another language. Theological arguments are displacements. The speech that speaks the truth about essential things comes to meet us from its housing in particular languages and times. Which does not mean that the text may be re-written. What we understand in our own language is another language; what is made accessible to our world is another relation to the world. [source] Predictive ability of propofol effect,site concentrations during fast and slow infusion ratesACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2010P. O. SEPÚLVEDA Background: The performance of propofol effect,site pharmacokinetic models during target-controlled infusion (TCI) might be affected by propofol administration rate. This study compares the predictive ability of three effect,site pharmacokinetic models during fast and slow infusion rates, utilizing the cerebral state index (CSI) as a monitor of consciousness. Methods: Sixteen healthy volunteers, 21,45 years of age, were randomly assigned to receive either a bolus dose of propofol 1.8 mg/kg at a rate of 1200 ml/h or an infusion of 12 mg/kg/h until 3,5 min after loss of consciousness (LOC). After spontaneous recovery of the CSI, the bolus was administered to patients who had first received the infusion and vice versa. The study was completed after spontaneous recovery of CSI following the second dose scheme. LOC was assessed and recorded when it occurred. Adequacies of model predictions during both administration schemes were assessed by comparing the effect,site concentrations estimated at the time of LOC during the bolus dose and during the infusion scheme. Results: LOC occurred 0.97 ± 0.29 min after the bolus dose and 6.77 ± 3.82 min after beginning the infusion scheme (P<0.05). The Ce estimated with Schnider (ke0=0.45/min), Marsh (ke0=1.21/min) and Marsh (ke0=0.26/min) at LOC were 4.40 ± 1.45, 3.55 ± 0.64 and 1.28 ± 0.44 ,g/ml during the bolus dose and 2.81 ± 0.61, 2.50 ± 0.39 and 1.72 ± 0.41 ,g/ml, during the infusion scheme (P<0.05). The CSI values observed at LOC were 70 ± 4 during the bolus dose and 71 ± 2 during the infusion scheme (NS). Conclusion: Speed of infusion, within the ranges allowed by TCI pumps, significantly affects the accuracy of Ce predictions. The CSI monitor was shown to be a useful tool to predict LOC in both rapid and slow infusion schemes. [source] Internal Thoracic Arterial Grafts Evaluation by Multislice CT Scan:JOURNAL OF CARDIAC SURGERY, Issue 6 2004A Preliminary Study The aim of this study is to evaluate the multidetector multislice CT Scan (MCTS) as a means of postoperative evaluation of ITA coronary artery bypass grafts. Methods: Twenty-eight patients having been operated on for coronary artery bypass with ITA during a 6-months period, benefited, 7 days after surgery, from a patency and anastomotic site control of ITA with a MCTS associated with cardiac gating (Light Speed, General Electric, USA). Results: Internal thoracic artery bypasses are visualized perfectly on all their courses, with possibility of 3D reconstructions, showing the relationship between cardiac cavities and the arterial bypasses. The anastomotic site on the LAD was, in selected cases, perfectly visualized. Sequential bypasses with left ITA are well visualized as well as T or Y right-to-left ITA grafts. However, surgical clips create some image artefacts. Conclusions: The postoperative control of ITAs are possible by MCTS with a satisfactory resolution. This makes it possible to check the patency of ITAs, their course on the heart surface, and the location and quality of anastomosis with a noninvasive reproductive method. [source] Patterns of performance degradation and restoration during sleep restriction and subsequent recovery: a sleep dose-response studyJOURNAL OF SLEEP RESEARCH, Issue 1 2003Gregory Belenky SUMMARY Daytime performance changes were examined during chronic sleep restriction or augmentation and following subsequent recovery sleep. Sixty-six normal volunteers spent either 3 (n = 18), 5 (n= 16), 7 (n = 16), or 9 h (n = 16) daily time in bed (TIB) for 7 days (restriction/augmentation) followed by 3 days with 8 h daily TIB (recovery). In the 3-h group, speed (mean and fastest 10% of responses) on the psychomotor vigilance task (PVT) declined, and PVT lapses (reaction times greater than 500 ms) increased steadily across the 7 days of sleep restriction. In the 7- and 5-h groups speed initially declined, then appeared to stabilize at a reduced level; lapses were increased only in the 5-h group. In the 9-h group, speed and lapses remained at baseline levels. During recovery, PVT speed in the 7- and 5-h groups (and lapses in the 5-h group) remained at the stable, but reduced levels seen during the last days of the experimental phase, with no evidence of recovery. Speed and lapses in the 3-h group recovered rapidly following the first night of recovery sleep; however, recovery was incomplete with speed and lapses stabilizing at a level comparable with the 7- and 5-h groups. Performance in the 9-h group remained at baseline levels during the recovery phase. These results suggest that the brain adapts to chronic sleep restriction. In mild to moderate sleep restriction this adaptation is sufficient to stabilize performance, although at a reduced level. These adaptive changes are hypothesized to restrict brain operational capacity and to persist for several days after normal sleep duration is restored, delaying recovery. [source] Venture Creation Speed and Subsequent Growth: Evidence from South AmericaJOURNAL OF SMALL BUSINESS MANAGEMENT, Issue 3 2010Joan-Lluis Capelleras Though time is an important dimension of the venture creation process, our understanding of why some entrepreneurs are able to act more quickly than others is limited. Equally, not much is known about the relationship between venture creation speed and the subsequent venture growth. In this paper, we use a resource-based perspective to provide insights into the factors that quicken or retard venture creation and to explore how speed impacts on subsequent growth. This is important because the topic remains generally underresearched and because even less is understood about venture creation speed in the context of South American economies. Data were collected from face-to-face interviews with 647 entrepreneurs in Argentina, Brazil, Chile, and Peru. Using a multivariate regression framework, we find that entrepreneurs make use of their human and social capital resources to shape the speed by which their venture is created. Moreover, their perceptions of unfavorable environmental conditions seem to retard venture creation. Findings also suggest that entrepreneurs who take more time to create a more solid resource base tend to receive better growth outcomes. Implications from the findings are discussed. [source] Speed- and topography-dependent boundary friction characteristics of steelLUBRICATION SCIENCE, Issue 8 2010Saiko Aoki Abstract A novel tribometer that undergoes significant changes at ultra-slow (>5.0,µm,s,1) to moderate (<20,cm,s,1) sliding speeds was developed in order to study the friction-speed characteristics of steel lubricated with oil. Three different surface topographies were applied to the specimens, and the friction characteristics with an additive-free base oil (MO91) and a stearic acid-formulated oil (StA/MO91) were studied to understand the effects of surface textures on the lubrication performance of an adsorbed molecular layer formed by StA. Friction reduction behaviour of the adsorbed layer observed in the transverse direction was attributed to microscopic hydrodynamic action that maintained the load-carrying performance of the adsorbed layer. Copyright © 2010 John Wiley & Sons, Ltd. [source] Deterministic and statistical methods for reconstructing multidimensional NMR spectra,MAGNETIC RESONANCE IN CHEMISTRY, Issue 3 2006Ji Won Yoon Abstract Reconstruction of an image from a set of projections is a well-established science, successfully exploited in X-ray tomography and magnetic resonance imaging. This principle has been adapted to generate multidimensional NMR spectra, with the key difference that, instead of continuous density functions, high-resolution NMR spectra comprise discrete features, relatively sparsely distributed in space. For this reason, a reliable reconstruction can be made from a small number of projections. This speeds the measurements by orders of magnitude compared to the traditional methodology, which explores all evolution space on a Cartesian grid, one step at a time. Speed is of crucial importance for structural investigations of biomolecules such as proteins and for the investigation of time-dependent phenomena. Whereas the recording of a suitable set of projections is a straightforward process, the reconstruction stage can be more problematic. Several practical reconstruction schemes are explored. The deterministic methods,additive back-projection and the lowest-value algorithm,derive the multidimensional spectrum directly from the experimental projections. The statistical search methods include iterative least-squares fitting, maximum entropy, and model-fitting schemes based on Bayesian analysis, particularly the reversible-jump Markov chain Monte Carlo procedure. These competing reconstruction schemes are tested on a set of six projections derived from the three-dimensional 700-MHz HNCO spectrum of a 187-residue protein (HasA) and compared in terms of reliability, absence of artifacts, sensitivity to noise, and speed of computation. Copyright © 2006 John Wiley & Sons, Ltd. [source] Book Reviews: Rights in Rebellion: Indigenous Struggle and Human Rights in Chiapas by Shannon SpeedAMERICAN ANTHROPOLOGIST, Issue 3 2010Mark Goodale No abstract is available for this article. [source] | ||||||||||||||||||||||||||||||||||||||||