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Global Efficiency (global + efficiency)
Selected AbstractsAltered small-world brain functional networks in children with attention-deficit/hyperactivity disorderHUMAN BRAIN MAPPING, Issue 2 2009Liang Wang Abstract In this study, we investigated the changes in topological architectures of brain functional networks in attention-deficit/hyperactivity disorder (ADHD). Functional magnetic resonance images (fMRI) were obtained from 19 children with ADHD and 20 healthy controls during resting state. Brain functional networks were constructed by thresholding the correlation matrix between 90 cortical and subcortical regions and further analyzed by applying graph theoretical approaches. Experimental results showed that, although brain networks of both groups exhibited economical small-world topology, altered functional networks were demonstrated in the brain of ADHD when compared with the normal controls. In particular, increased local efficiencies combined with a decreasing tendency in global efficiencies found in ADHD suggested a disorder-related shift of the topology toward regular networks. Additionally, significant alterations in nodal efficiency were also found in ADHD, involving prefrontal, temporal, and occipital cortex regions, which were compatible with previous ADHD studies. The present study provided the first evidence for brain dysfunction in ADHD from the viewpoint of global organization of brain functional networks by using resting-state fMRI. Hum Brain Mapp, 2009. © 2008 Wiley-Liss, Inc. [source] Similar subcortical pattern of cognitive impairment in AIDS patients with and without dementiaEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2000S. V. Suarez The aim of this study was to develop a series of neuropsychological tests that define the cortical and subcortical features of cognitive impairment and the characteristics of memory in demented and mildly cognitively impaired AIDS patients. We attempted to establish a usable method to assess and determine the type and degree of cognitive impairment in individual AIDS patients. We examined 53 patients without central nervous system opportunistic infections. A short battery included two scales of global efficiency (the Mattis dementia rating scale and the Mini Mental State Examination), a psychomotor speed test, an executive control assessment and explicit memory evaluation. Patients were categorized into four groups based on their score on both the Mattis dementia rating scale and the DSM-IV criteria: (1) asymptomatic; (2) having AIDS without cognitive impairment; (3) having AIDS with mild cognitive impairment; and (4) having AIDS dementia. Patients with mildly impaired cognition demonstrated slowed thinking, abnormal initiation and conceptualization, and memory impairment. AIDS dementia patients had slower motor activity and memory recall was more severely affected. The short neuropsychological battery was able to characterize modified cognitive performances in both severely and mildly cognitively impaired AIDS patients. The subcortical pattern of the memory disorder was obvious, regardless of the degree of cognitive impairment. [source] High-speed-range enhancement of switched reluctance motor with continuous mode for automotive applicationsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 7 2008M. Rekik Abstract This paper describes an original method for the elaboration of control laws for the Switched Reluctance Motor (SRM) for high-speed operation. In this case, the control optimisation relies on the choice of optimal turn-on and turn-off angles to ensure, in general, high global efficiency, in classical supply mode with full-wave voltage. Then, after showing the influence of number of turns, a new supply mode called the continuous mode is described. This mode, used with a higher number of turns, allows to reduce the inverter current rating and hence silicon requirements without compromising performance at high speed. This makes the SRM competitive compared to other technologies (synchronous and induction motors). The simulation results for a 12/8 SRM are presented and compared to those for an induction motor. Copyright © 2007 John Wiley & Sons, Ltd. [source] Balancing global and local strategic contexts: Expatriate knowledge transfer, applications, and learning within a transnational organizationHUMAN RESOURCE MANAGEMENT, Issue 4 2007J. Barry Hocking We investigate how expatriates contribute to the transnational firm's strategic objectives of global efficiency, national ("local") responsiveness, and worldwide learning. We focus on expatriate knowledge application and experiential learning achievements, two assignment-based outcomes of potential strategic value to the firm. We assess how the individual's everyday knowledge access and communication activities, measured by frequency and geographic extent, affect these assignment outcomes. Within our case organization, a prototype transnational firm, we find that expatriate knowledge applications result from frequent knowledge access and communication with the corporate headquarters and other global units of the firm. In contrast, their experiential learning derives from frequent access to hostcountry (local) knowledge that subsequently is adapted to the global corporate context. From a practical perspective, we conclude that experiential learning is an invaluable resource for both present and future corporate assignments. © 2007 Wiley Periodicals, Inc. [source] Large eddy simulation of turbulent flows via domain decomposition techniques.INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2005Part 1: theory Abstract The present paper discusses large eddy simulations of incompressible turbulent flows in complex geometries. Attention is focused on the application of the Schur complement method for the solution of the elliptic equations arising from the fractional step procedure and/or the semi-implicit discretization of the momentum equations in velocity,pressure representation. Fast direct and iterative Poisson solvers are compared and their global efficiency evaluated both in serial and parallel architecture environments for model problems of physical relevance. Copyright © 2005 John Wiley & Sons, Ltd. [source] AGGLOMERATION VERSUS PRODUCT VARIETY: IMPLICATIONS FOR REGIONAL INEQUALITIES,JOURNAL OF REGIONAL SCIENCE, Issue 5 2006Kristian Behrens ABSTRACT We investigate how cross-country differences in firms' fixed set-up costs affect the trade-off between global efficiency and spatial equity. Our analysis reveals that the standard assumption of symmetry in set-up costs masks the existence of an interesting effect: the range of available varieties depends on the spatial distribution of firms. In such a setting, where the market outcome leads to excessive agglomeration in the symmetric case, a planner may opt for asymmetric set-up costs and even more agglomeration. We show that the planner will always favor lower set-up costs in the large country with more agglomeration when the consumer's marginal preference for variety is high, or with less agglomeration when the consumer's marginal preference for variety is low. [source] | ||||||||||