3,132 research outputs found
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The blossoming of data communications and the thorns of computer crimes: An analysis of the use and abuse of network computing
Lagrangian Based Methods for Coherent Structure Detection
There has been a proliferation in the development of Lagrangian analytical methods for detecting coherent structures in fluid flow transport, yielding a variety of qualitatively different approaches. We present a review of four approaches and demonstrate the utility of these methods via their application to the same sample analytic model, the canonical double-gyre flow, highlighting the pros and cons of each approach. Two of the methods, the geometric and probabilistic approaches, are well established and require velocity field data over the time interval of interest to identify particularly important material lines and surfaces, and influential regions, respectively. The other two approaches, implementing tools from cluster and braid theory, seek coherent structures based on limited trajectory data, attempting to partition the flow transport into distinct regions. All four of these approaches share the common trait that they are objective methods, meaning that their results do not depend on the frame of reference used. For each method, we also present a number of example applications ranging from blood flow and chemical reactions to ocean and atmospheric flows. (C) 2015 AIP Publishing LLC.ONR N000141210665Center for Nonlinear Dynamic
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A hierarchy fuzzy MCDM method for studying electronic marketing strategies in the information service industry
In this paper the impacts of Electronic Commerce {EC) on the international marketing strategies for the information service industries are studied. In seeking to blend humanistic concerns in this research with technological development by addressing challenges for deterministic attitudes, it also examines critical environmental factors relevant to Internet commerce in the changes of the international marketing environment. The needs for a new marketing paradigm for EC, which comes out of new trends of international electronic marketing, are also examined. The impacts of EC for the information service industry are discussed and a hierarchy fuzzy multicriteria decision-making (Fuzzy MCDM) method for evaluating the propagating EC market strategies is proposed. Finally, in order to show the practicability and usefulness in this method, an example is taken as a verifiable method. From the results of practical applications in evaluating the electronic marketing strategies, the proposed method is appropriate and appears to be ideal for a fuzzy environment
Hashimoto’s encephalopathy cases: Chinese experience
BACKGROUND: Hashimoto’s encephalopathy is a poorly understood syndrome consisting of heterogeneous neurological symptoms and high serum antithyroid antibody titers, typically responding to steroids. More clinical series studies are required to characterize the clinical, laboratory and imaging features, and outcomes, especially in the Chinese population. METHODS: We analyzed the clinical, laboratory, and imaging features and outcomes of thirteen consecutive patients with Hashimoto’s encephalopathy diagnosed in Xuan Wu Hospital, Beijing from 2005 to 2010 retrospectively. RESULTS: Cognitive impairment (84.6%) and psychiatric symptoms (38.5%) were the most frequent symptoms. Seizures (30.8%) and myoclonus (7.7%) were less common than previously described. Three (23.1%) patients showed abnormal signals in hippocampus or temporal lobe, which were believed related to their memory disorders or seizures. MRI changes showed resolution paralleling clinical improvement in one patient. Among eight patients who received steroid therapy, five patients recovered, one patient improved with residual deficits, and two patients relapsed or had no effect. Among five non-steroid treated patients, three patients experienced stable remission with antiepileptic drugs or general neurotrophic therapy, and two patients experienced continuous deterioration. CONCLUSIONS: Most patients with Hashimoto’s encephalopathy showed good response to steroids. Some patients improved without steroid therapy. Considering its reversible course, we recommend that Hashimoto’s encephalopathy should always be in the differential diagnosis while evaluating disorders of the central nervous system
Aerothermodynamic Design of the Mars Science Laboratory Heatshield
Aerothermodynamic design environments are presented for the Mars Science Laboratory entry capsule heatshield. The design conditions are based on Navier-Stokes flowfield simulations on shallow (maximum total heat load) and steep (maximum heat flux, shear stress, and pressure) entry trajectories from a 2009 launch. Boundary layer transition is expected prior to peak heat flux, a first for Mars entry, and the heatshield environments were defined for a fully-turbulent heat pulse. The effects of distributed surface roughness on turbulent heat flux and shear stress peaks are included using empirical correlations. Additional biases and uncertainties are based on computational model comparisons with experimental data and sensitivity studies. The peak design conditions are 197 W/sq cm for heat flux, 471 Pa for shear stress, 0.371 Earth atm for pressure, and 5477 J/sq cm for total heat load. Time-varying conditions at fixed heatshield locations were generated for thermal protection system analysis and flight instrumentation development. Finally, the aerothermodynamic effects of delaying launch until 2011 are previewed
Predictors of short-term clinical response to cardiac resynchronization therapy
Aims:
Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with symptomatic heart failure and QRS prolongation but there is uncertainty about which patient characteristics predict short-term clinical response.
Methods and results:
In an individual patient meta-analysis of three double-blind, randomized trials, clinical composite score (CCS) at 6 months was compared in patients assigned to CRT programmed on or off. Treatment–covariate interactions were assessed to measure likelihood of improved CCS at 6 months. MIRACLE, MIRACLE ICD, and REVERSE trials contributed data for this analysis (n = 1591). Multivariable modelling identified QRS duration and left ventricular ejection fraction (LVEF) as predictors of CRT clinical response (P < 0.05). The odds ratio for a better CCS at 6 months increased by 3.7% for every 1% decrease in LVEF for patients assigned to CRT-on compared to CRT-off, and was greatest when QRS duration was between 160 and 180 ms.
Conclusions:
In symptomatic chronic heart failure patients (NYHA class II–IV), longer QRS duration and lower LVEF independently predict early clinical response to CRT
International Technology Diffusion of Joint and Cross-border Patents
With the advent of globalization, economic and financial interactions among countries have become widespread. Given technological advancements, the factors of production can no longer be considered to be just labor and capital. In the pursuit of economic growth, every country has sensibly invested in international cooperation, learning, innovation, technology diffusion and knowledge. In this paper, we use a panel data set of 40 countries from 1981 to 2008 and a negative binomial model, using a novel set of cross-border patents and joint patents as proxy variables for technology diffusion, in order to investigate such diffusion. The empirical results suggest that, if it is desired to shift from foreign to domestic technology, it is necessary to increase expenditure on R&D for business enterprises and higher education, exports and technology. If the focus is on increasing bilateral technology diffusion, it is necessary to increase expenditure on R&D for higher education and technology
Similarity-Detection and Localization
The detection of similarities between long DNA and protein sequences is
studied using concepts of statistical physics. It is shown that mutual
similarities can be detected by sequence alignment methods only if their amount
exceeds a threshold value. The onset of detection is a continuous phase
transition which can be viewed as a localization-delocalization transition. The
``fidelity'' of the alignment is the order parameter of that transition; it
leads to criteria for the selection of optimal alignment parameters.Comment: 4 pages including 4 figures (308kb post-script file
Joint and Cross-border Patents as Proxies for International Technology Diffusion
With the advent of globalization, economic and financial interactions among countries have become widespread. Given technological advancements, the factors of production can no longer be considered to be just labor and capital. In the pursuit of economic growth, every country has sensibly invested in international cooperation, learning, innovation, technology diffusion and knowledge, and outward direct investment. In this paper, we use a panel data set of 40 countries from 1981 to 2008 and a negative binomial model, using a novel set of cross-border patents and joint patents as proxy variables for technology diffusion, in order to investigate such diffusion.
The empirical results suggest that, if it is desired to shift from foreign to domestic technology, it is necessary to increase expenditure on R&D for business enterprises and higher education, exports and technology. If the focus is on increasing bilateral technology diffusion, it is necessary to increase expenditure on R&D for higher education and technology. It is also found that outward foreign direct investment has no significant impact on either joint or cross-border patents, whereas inward foreign direct investment has a significant negative impact on cross-border patents but no impact on joint patents. Moreover, government expenditure on higher education has a significant impact on both cross-border and joint patent
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