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The issue of hadron deformation has been a subject of intense scientific interest during the last two decades. The detailed study of the N→△ transition has emerged as the prefered method of experimental investigation of this iss...
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The issue of hadron deformation has been a subject of intense scientific interest during the last two decades. The detailed study of the N→△ transition has emerged as the prefered method of experimental investigation of this issue. A brief overview of the experimental and theoretical landscape on the field is presented followed by a presentation of the most recent results from the Bates and Mainz N →△ programs which focus at the low Q2 region. The experimental data yield precise non zero quadrupole to dipole amplitude EMR and CMR ratios, giving credence to the conjecture of deformation in hadrons favoring the attribution of the origin of deformation at the low Q2 region to the dominance of mesonic effects.
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The study of the γ ?N →Δ reaction presents the best quantitative method to explore the deviation of hadron shapes from spherical symmetry (nonspherical amplitudes). Significant non-spherical electric (E2) and Coulomb quadrupole...
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The study of the γ ?N →Δ reaction presents the best quantitative method to explore the deviation of hadron shapes from spherical symmetry (nonspherical amplitudes). Significant non-spherical electric (E2) and Coulomb quadrupole (C2) amplitudes have been observed with good precision as a function of Q~2 from photon point up to ≈ 7 (GeV/c)~2. Quark model calculations for these quadrupole amplitudes are at least an order of magnitude too small and even have the wrong sign. Lattice QCD, chiral effective field theory, and dynamic model calculations which include the effects of the pion-cloud are in approximate agreement with experiment.
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Biodegradation of polylactide (PLA) under real composting conditions was investigated, and the results were compared with biodegradation values obtained in three simulated laboratory conditions (i.e., cumulative (CMR), gravimetric...
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Biodegradation of polylactide (PLA) under real composting conditions was investigated, and the results were compared with biodegradation values obtained in three simulated laboratory conditions (i.e., cumulative (CMR), gravimetric (GMR) and direct (DMR) methods). Laboratory conditions underrepresent the biodegradation that takes place in real composting conditions. PLA bottles completely biodegraded in 30 days in real composting while 60% mineralization was reached at 38 days in the CMR method, 45 days in the GMR method, and 55 days in the DMR method.
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Magnetic resonance imaging is a highly advanced reference imaging modality for cardiac morphology, function and perfusion in humans. A framework is proposed for automatic ventricular analysis using cardiac magnetic resonance image...
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Magnetic resonance imaging is a highly advanced reference imaging modality for cardiac morphology, function and perfusion in humans. A framework is proposed for automatic ventricular analysis using cardiac magnetic resonance images. The short axis cine CMR images are corrected for intensity-inhomogeneity using Bias Corrected Fuzzy C-Means method. Ventricular Segmentation of CMR images is important to quantitatively analyze global and regional cardiac function. Extraction of morphological and functional features of CMR images helps in diagnosis of various cardiovascular diseases. The effectiveness of the proposed framework is verified by the experimental results on real CMR images.
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Cardiac Magnetic Resonance Imaging (CMR) is a central tool for diagnosis of various ischemic and non-ischemic cardiomyopathies. CMR protocols commonly comprise assessment of functional properties using cardiac phase-resolved CINE ...
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Cardiac Magnetic Resonance Imaging (CMR) is a central tool for diagnosis of various ischemic and non-ischemic cardiomyopathies. CMR protocols commonly comprise assessment of functional properties using cardiac phase-resolved CINE MRI and characterization of myocardial viability using late gadolinium enhancement (LGE) imaging. Conventional LGE imaging requires inversion recovery preparation with a specific inversion time to null the healthy myocardium, which restricts the acquisition to a single cardiac phase. In turn, this necessitates separate scans for cardiac function and viability. In this work, we develop a new method for functional LGE imaging in a single breath-hold using a three-step approach: 1) ECG-triggered multi-contrast data is acquired for each cardiac phase, 2) semi-quantitative relaxation maps are generated, 3) LGE imaging contrast is synthesized based on the semiquantitative maps. The proposed functional LGE method is evaluated in four healthy subject and 20 patients at 1.5T and 3T. Thorough suppression of the healthy myocardium, as well as 40-80ms temporal resolution are achieved, with no visually apparent temporal blurring at tissue interfaces. Functional LGE in patients with focal scar demonstrates robust hyperenhancement in the scar area throughout all cardiac phases, allowing for visual assessment of scar motility. The proposed technique bears the potential to simplify and speedup common cardiac imaging protocols, while enabling improved data fusion of functional and viability information for improved evaluation of CMR.
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A compound of La_(0.7)Ba_(0.297)Ca_(0.003)MnO_3 was obtained by low temperature sol-gel synthesis. The structural and electrical properties of the material were systematically studied. La_(0.7)B_(a0.297)Ca_(0.003)MnO_3 material is...
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A compound of La_(0.7)Ba_(0.297)Ca_(0.003)MnO_3 was obtained by low temperature sol-gel synthesis. The structural and electrical properties of the material were systematically studied. La_(0.7)B_(a0.297)Ca_(0.003)MnO_3 material is a member of mixed valence manganites which has a perovskite structure. The general structure isAMnO3 (A=trivalent rare earth with divalent ion-doped such as Sr~(2+), Ca~(2+), Ba~(2+), etc). The previous study proved that doped Ca~(2+) ion to the La_(0.7)Ba_(0.3)MnO_3 material increased its CMR effect and MCE effect and decreased its T_c become near room temperature. CMR effect is change of resistivity due to external magnetic field in the perovskite-based material. Meanwhile, MCE (Magnetocaloric effect) is thermal response from material due to external magnetic field. In this work, we focus only on the electrical properties of La_(0.7)Ba0.297Ca0.003MnO_3 (low doped calcium content in the La_(0.7)Ba_(0.3)MnO_3 material) obtained by low temperature sol-gel synthesis. The X-ray diffraction pattern shows that the material is fully crystalline with a rhombohedral structure and R-3c space group. Polycrystalline La_(0.7)B_(a0.297)Ca_(0.003)MnO_3 has magnetic transition behavior from metallic-ferromagnetic behavior to the insulator-paramagnetic behavior with increasing temperature. This material also has magnetoresistance effect. Magnetoresistance value of the material is about 9% at 280 K under an external magnetic field of 1.5 T. In this case, extrinsic MR (extrinsic magnetoresistance) plays an important role since the material is polycrystalline. From this study, we conclude that with low temperature processing we obtained material that has CMR effect and magnetic transition phenomenon like material which prepared by high temperature processing.
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Electrostatic spray relative to non-electrostatic spray has an outstanding advantage in deposit distribution and canopy penetration aspects. In order to study the effect of the flow rate, volume diameter and Charge to Mass Ratio (...
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Electrostatic spray relative to non-electrostatic spray has an outstanding advantage in deposit distribution and canopy penetration aspects. In order to study the effect of the flow rate, volume diameter and Charge to Mass Ratio (CMR) to the spray deposition in electrostatic spraying, three sprayers and six nozzles were used under the same conditions to test the flow rate, volume diameter, charge to mass ratio and droplets coverage. The results showed that flow rate, volume diameter and charge to mass ratio all have effect on electrostatic spraying coverage. And in accordance the order of priority of coverage influence from strong to weak is as follows: the charge to mass ratio, volume diameter, and flow rate.
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The goal of this study was to develop a near-automated technique for the segmentation of left ventricular (LV) endo- and epicardial as well as right ventricular (RV) endocardial contours from cardiac magnetic resonance (CMR) image...
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The goal of this study was to develop a near-automated technique for the segmentation of left ventricular (LV) endo- and epicardial as well as right ventricular (RV) endocardial contours from cardiac magnetic resonance (CMR) images. The newly developed technique was tested against conventional manual tracing. Our approach is based on a 3D narrow-band statistical level-set algorithm (applied to a stack of CMR short-axis images) followed by several refinement steps. This technique was tested on steady-state free precession (SSFP) CMR images acquired during 10-15 sec breath-holds in 6 patients, including a total of 120 images. Computational time was around 3 min for a stack of 10 slices. For performance evaluation, an experienced interpreter manually traced ventricular contours on all the images. Quantitative error metrics (Hausdorff distance, HD; mean absolute distance, MAD, Dice coefficient, DC) were computed between automatically identified and manually traced contours. Bland-Altman and linear regression analyses were also performed between automatically and manually computed ventricular volumes. The results (MAD: LV Endo = 1.3±0.7 px, RVEndo = 1.7±1.2 px, LVEpi = 1.5±0.7px) indicate that fast and accurate identification of LV and RV contours using 3D narrow-band statistical level-sets is feasible.
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The strong interest to study microwave features of modem artificial materials occurs. One of prospective candidates for such a role are Sr-doped lanthanum manganites-perovskites. Due to special interparticles interactions in the p...
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The strong interest to study microwave features of modem artificial materials occurs. One of prospective candidates for such a role are Sr-doped lanthanum manganites-perovskites. Due to special interparticles interactions in the perovskite lattice they show a number of unique properties, including in particular, the colossal magnetoresistance — CMR [1]. The essence of the CMR phenomenon consists in the abrupt increase of electric resistance under the impact of the external static magnetic field. Mainly due to this effect doped manginites are considered as promising materials for design of novel generation of magnetic sensors and devices of the magnetic information read-out, for novel generation of magnetically controlled microwave and terahertz devices [2]. On the other hand, lanthanum manganites are very interesting object as a model of so-called "left handed" media i.e. media which demonstrate the negativity of refraction coefficient [3].
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We study the origin of the colour magnitude relation (CMR) in the Virgo cluster. The CMR could be either caused by a variation of the mean stellar metallicity along the sequence (Kodama and Arimoto, 1997) or by a combination of ag...
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We study the origin of the colour magnitude relation (CMR) in the Virgo cluster. The CMR could be either caused by a variation of the mean stellar metallicity along the sequence (Kodama and Arimoto, 1997) or by a combination of age and metallicity variations (Ferreras, Charlot and Silk, 1999). This uncertainty is due to the fact that the integrated light of the stellar populations suffers from a degeneracy between the age and the metallicity, i.e., the two effects cannot easily be separated using colours or absorption line-strengths (Worthey, 1994). We use spectra of exceptional high S/N (obtained at the WHT 4.2m telescope, La Palma) for six elliptical galaxies well selected along the CMR of Bower, Lucey and Ellis (1992a,b) following their best-fit regression line. The data are analysed using a new evolutionary stellar population synthesis model which has the ability to study galaxy spectra at the resolution given by their velocity dispersions (Vazdekis, 1999). We estimate the mean stellar ages for these galaxies using a new Hγ age indicator which is completely insensitive to the metallicity (in the range -0.7<[Fe/H]<+0.2) for old stellar population (Vazdekis and Arimoto, 1999). We find that the luminosity weighted mean stellar ages for all these galaxies are larger than ~ 8 Gyr, showing a significant spread in age but without a clear trend as a function of galaxy luminosity or colour. Taking into account these ages and analising the strengths of several metal lines we find a positive correlation of the total metallicity with luminosity, colour and velocity dispersion. However, while various metal-indicators dominated by elements such as Mg or CN yield very steep index-luminosity relations, others such as Fe or Ca show modest trends. An extensive analysis is presented in Vazdekis et al. (2000).
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