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Effective Area (effective + area)
Selected AbstractsMRI verified STN stimulation site , gait improvement and clinical outcomeEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2010E. L. Johnsen Background:, Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective in alleviating Parkinson's disease (PD) symptoms (tremor, rigidity and bradykinesia) and may improve gait and postural impairment associated with the disease. However, improvement of gait is not always as predictable as the clinical outcome. This may relate to the type of gait impairment or localization of the active DBS contact. Methods:, The active contact was visualized on peri-operative magnetic resonance imaging in 22 patients with idiopathic PD, consecutively treated with bilateral STN DBS. Stimulation site was grouped as either in the dorsal/ventral STN or medial/lateral hereof and anterior/posterior STN or medial/lateral hereof. The localization was compared with relative improvement of clinical outcome (UPDRS-III). In 10 patients, quantitative gait analyses were performed, and the improvement in gait performance was compared with stimulation site in the STN. Results:, Of 44 active contacts, 77% were inside the nucleus, 23% were medial hereof. Stimulation of the dorsal half improved UPDRS-III significantly more than ventral STN DBS (P = 0.02). However, there were no differences between anterior and posterior stimulation in the dorsal STN. Step velocity and length improved significantly more with dorsal stimulation compared with ventral stimulation (P = 0.03 and P = 0.02). Balance during gait was also more improved with dorsal stimulation compared with ventral stimulation. Conclusions:, Deep brain stimulation of the dorsal STN is superior to stimulation of the ventral STN. Possible different effects of stimulation inside the nucleus underline the need for exact knowledge of the active stimulation site position to target the most effective area. [source] Failure envelopes and plastic potentials for eccentrically loaded surface footings on undrained soilINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 4 2001M. Fraser Bransby Abstract The failure envelope in V,M space for surface foundations on undrained material under eccentric loading can be determined using an extended version of the scaling (or effective area) concept of Meyerhof. A similar displacement transformation allows production of the plastic potential. The two-dimensional finite element analyses of fully attached foundations subject to combined vertical (V) and moment (M) loading have been used to calculate appropriate scaling points for deduction of the failure envelope and plastic potential. Failure envelopes and plastic potentials are presented for footings on uniform and non-uniform undrained material and it is seen that the equivalent ,critical state' or ,parallel point' lies slightly beneath the peak moment capacity. For accurate prediction of failure envelopes for footings on non-uniform strength soil, consideration must be made of the apparent reduction of the soil heterogeneity as the area of footing in contact with the soil decreases. Copyright © 2001 John Wiley & Sons, Ltd. [source] Size Scaling of Tensile Failure Stress in a Float Soda,Lime,Silicate GlassINTERNATIONAL JOURNAL OF APPLIED GLASS SCIENCE, Issue 2 2010Andrew A. Wereszczak The (tensile) strength,size scaling of a float soda,lime,silicate glass was studied using biaxial flexure and Hertzian ring crack initiation testing. The examined Weibull effective areas spanned ,0.4,48,000 mm2. Both the air and tin sides were tested. The air side was stronger than the tin side as others have observed; however, the differences in their characteristic strengths decreased with a decreasing effective area, and their strengths converged for effective areas smaller than ,100 mm2. The failure stress at the smallest effective area examined for the tin side was ,500% greater than that at the largest effective area, while that difference was ,250% for the air side. A Weibull modulus change at ,100 mm2 suggests different strength-limiting flaw types were dominant below and above this effective area. These results reinforce the importance of the interpretation and use of the tensile strength of glass in context to how much of its area is being subjected to tensile stress. [source] High-energy X-ray diffraction using the Pixium 4700 flat-panel detectorJOURNAL OF SYNCHROTRON RADIATION, Issue 4 2009J. E. Daniels The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction. The detector design is based on digital flat-panel technology, combining an amorphous Si panel with a CsI scintillator. The detector has a useful pixel array of 1910 × 2480 pixels with a pixel size of 154,µm × 154,µm, and thus it covers an effective area of 294,mm × 379,mm. Designed for medical imaging, the detector has good efficiency at high X-ray energies. Furthermore, it is capable of acquiring sequences of images at 7.5 frames per second in full image mode, and up to 60 frames per second in binned region of interest modes. Here, the basic properties of this detector applied to high-energy X-ray diffraction are presented. Quantitative comparisons with a widespread high-energy detector, the MAR345 image plate scanner, are shown. Other properties of the Pixium 4700 detector, including a narrow point-spread function and distortion-free image, allows for the acquisition of high-quality diffraction data at high X-ray energies. In addition, high frame rates and shutterless operation open new experimental possibilities. Also provided are the necessary data for the correction of images collected using the Pixium 4700 for diffraction purposes. [source] Simple models for predicting transmission properties of photonic crystal fibersMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2006Rachad Albandakji Abstract Simple, fast, and efficient 1D models for evaluating the transmission properties of photonic crystal fibers are proposed. Using these models, axial propagation constant, chromatic dispersion, effective area, and leakage loss can be predicted with a reasonable accuracy but much faster than often time-consuming 2D analytical and numerical techniques and with much less computational resources. It is shown that the results are in good agreement with the published data available in the literature. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1286,1290, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21624 [source] High-energy neutrino emission from low-mass microquasarsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010J. F. Zhang ABSTRACT In this paper we study the high-energy neutrino emission from low-mass microquasars (LMMQs) by assuming that an acceleration region for particles is located in the inner jet, based on the framework of a hadronic jet model. Adopting the parametrized formulae for inelastic pp interactions and the recent p, parametrizations, we calculate the spectral energy distributions (SEDs) of various photon and neutrino spectra. Furthermore, we also consider the electromagnetic cascade processes due to ,, absorption. We then apply the jet model to the microquasar (MQ) GX 339,4, and calculate the expected neutrino event rate for three years of observations using the newest effective area of the KM3NeT detector in the Mediterranean Sea. The resulting results indicate that (1) photon spectra can roughly reproduce observations from radio to X-ray energies, and can also predict emission fluxes at high and very high energies (VHE); (2) GX 339,4 is a potential neutrino source, neutrinos from which are likely to be identified with some years of observations from the next-generation -scale neutrino telescopes. [source] Electrical resistance variation of carbon-nanotube networks due to surface modification of glass substratePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2010Eui Yun Jang Abstract This study presents the effect of the wettability between a glass substrate and carbon-nanotube (CNT) colloidal solution on the density of CNT networks in a dip-coating process. The surface roughness and the density of functional groups of the glass substrate were modified by using an oxygen-plasma treatment, and then we observed the density of CNT networks with respect to different surface conditions due to the surface modification. It is confirmed that the surface chemical property and the surface morphology of the glass substrate determines the density of CNT networks formed by the dip-coating method. The change of surface free energy induced by hydroxylation and hydration enhances the wettability between a glass substrate and CNT colloidal solution. Moreover, the effective area on which silanol groups can be formed is dependent on the roughness of the surface of the substrate. Eventually, the change of the surface free energy due to the hydroxylation, hydration, and surface roughness effect on the density of the coated CNTs, which determines the sheet resistance of CNT networks. [source] Imaging geophysical data,taking the viewer into accountARCHAEOLOGICAL PROSPECTION, Issue 1 2004T. J. Dennis Abstract A common way of presenting geophysical data from two-dimensional sources is as a grey-scale image. Some theoretical background to discrete image representation is described, and the deleterious effects of inappropriate (too sparse) sampling and display of such images discussed in an archaeological context. In high-quality images, such as magazine illustrations or digital television, the sampling densities can be sufficiently high to avoid the appearance of artefacts. Geophysical images in contrast are often sampled at very low densities; if the effective area of each sample is significantly less than the sample spacing, then the classic effect called ,aliasing' in communication engineering, caused by the violation of Nyquist's criterion, will be seen. Knowledge of the sensor's footprint can be used to select an appropriate sample density, and so minimize this source of distortion. To maximize the visibility of what may be low-contrast structures immersed in a high level of background noise, it is helpful also to consider the bandpass nature of the spatial frequency response of the human visual system. The non-linear phenomenon of visual masking is shown to influence the choice on presentation methods. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effect of different electrode configurations on the migration of copper ions during the electrokinetic remediation processASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Juan Almeira Abstract Electrokinetic remediation (EKR) is becoming a popular technique for removal of heavy metals from polluted soils, but its low efficiency induced from high pH area should be improved. It is known that the proper arrangement of electric field direction and intensity may influence the migration of H+ and OH, by direction and distance, which means that basic and acid zones can be optimized through electric field orientation arrangement. The aim of this work is to study the influence of the arrangement of electrodes on acid/basic zone, minimizing basic area and maximizing acid area in the soil. In this paper, five soil samples named TQ1, TQ2, TQ2, B55, and B60 were treated by EKR with different two-dimensional (2D) electrodes arrangement, in order to investigate the effect of electrode configurations on the distribution of pH and copper ions removal. Based on the results of copper removal, energy consumption, effective area, and the percentage of acid, basic and pH jump area, the best electrode configuration would be a cathode,anode,cathode arrangement with 60° angle. It can also be seen from the results that only in the area of pH < 4, copper ions could be removed effectively. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Antenna performance analysis for decameter solar radio observationsASTRONOMISCHE NACHRICHTEN, Issue 7 2009A.A. Stanislavsky Abstract Decameter wavelength radio emission is finely structured in solar bursts. For their research it is very important to use a sufficient sensitivity of antenna systems. In this paper we study an influence of the radiotelescope-antenna effective area on the results of decameter solar radio observations. For this purpose we compared the solar bursts received by the array of 720 ground-based dipoles and the single dipole of the radiotelescope UTR-2. It is shown that a larger effective area of the ground-based antenna allows us to measure a weaker solar emission and to distinguish a fine structure of strong solar events. This feature has been also verified by simultaneous ground- and space-based observations in the overlapping frequency range (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Search for narrow energy-shifted lines in AGN spectra in the XMMNewton archive,ASTRONOMISCHE NACHRICHTEN, Issue 10 2006A. L. Longinotti Abstract Thanks to the large effective area and the spectral resolution of current X-ray satellites, the detection of X-ray narrow spectral features in the 5,7 keV band is becoming commonplace in many AGN observations. Such lines, both in emission and in absorption, are mostly interpreted as arising from Iron atoms. When observed with some displacement from their rest frame position, these lines carry the potential to study the motion of circumnuclear gas in AGN, providing a diagnostic of the effects of the gravitational field of the central black hole. These narrow features have been often found with marginal statistical significance. A systematic search for narrow features in type1 AGN is being performed on all spectra available in the XMM-Newton archive with the aim to estimate the significance of the features with Monte Carlo simulations of synthetic spectra. The project and preliminary results are presented. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||