Results 1 - 10 of 77703
Results 1 - 10 of 77703. Search took: 0.056 seconds
|Sort by: date | relevance|
[en] A new measurement of the b → Λb production fraction multiplied by the Λb → J/ψΛ branching fraction was performed by the D0 experiment using 6.1 fb-1 of p(bar p) collisions at √s = 1.96 TeV. The result of this measurement, f(b → Λb) · Β(Λb → J/ψΛ) = (6.01 ± 0.60 (stat.) ± 0.58 (syst.) ± 0.28 (PDG)) x 10-5, represents an improvement in precision by about a factor of three with respect to the current world average. We give an estimate of Β(Λb → J/ψΛ), which takes into account correlations among the different b-hadron production fractions and other weakly decaying baryons.
[en] A technique of measuring the magnetic flux, including the balancing of the differential coil system is described. To increase the accuracy, the differential coil system is placed in the magnetic field with the following alteration of the mutual orientation of the axis of the coil system and the magnetic field intensity vector up to the complete compensation of the output signal of the coil system. Coil axes of the differential system are not parallel
[en] A potentiometric titration of 5 to 25 mg uranium is described. Sulphamic and phosphoric acid are added to the sample (volume 1 ml), U VI is reduced to U IV by Fe2+ and the excess of Fe2+ is oxidized by a mixture of nitric acid, sulphamic acid and ammonium molybdate; vanadyl sulphate is added to ensure a sharp end-point of the titration. The resultant U IV is titrated automatically with 0.02500N potassiumdichromate using a platinum indicator electrode. The automatic titration is performed both with a commercial titrator (Mettler) and with an R.C.N. titrator which waits after each addition until the equilibrium is reached. Using the Mettler titrator an accuracy of 0.05% relative was reached. The R.C.N. setpoint titrator gave results with an accuracy of 0.04% relative at the 20-mg U level. Each titration takes 5 to 7 min. (author)
[en] First, let me express my appreciation to Professor Werner for his discussion of my paper. These are quite contentious and fiercely disputed questions, and the only way to make progress in resolving these disputes is to make a good faith effort to present the arguments clearly and explicitly. Only once things are pinned down on paper with some precision can a proper analysis proceed. Werner’s willingness to do this means progress can be made. There are some important points on which Werner and I agree. We agree that neither Einstein nor Bell presuppose determinism in framing their arguments, so the conclusions of those arguments cannot be avoided simply by adopting indeterminism. We even largely agree on what Bell thought he proved. For example, we agree that Bell did not take his theorem to refute determinism or ‘hidden variables’. Werner even seems to concede that Bell himself thought that he had proven the necessity for any theory that reproduces the predictions of the quantum formalism—or more generally any theory that predicts violations of his inequality for pairs of experiments done at space-like separation—to be non-local (in a particular sense of ‘non-local’). Agreement on this much is already a tremendous amount of progress, and I do not wish to undervalue it
[en] Purpose: The anatomical changes that occur between the simulation CT and daily cone-beam CT (CBCT) are investigated using an automated landmark-guided deformable image registration (LDIR) algorithm with simultaneous intensity correction. LDIR was designed to be accurate in the presence of tissue intensity mismatch and heavy noise contamination. Method: An auto-landmark generation algorithm was used in conjunction with a local small volume (LSV) gradient matching search engine to map corresponding landmarks between the CBCT and planning CT. The LSVs offsets were used to perform an initial deformation, generate landmarks, and correct local intensity mismatch. The landmarks act as stabilizing controlpoints in the Demons objective function. The accuracy of the LDIR algorithm was evaluated on one synthetic case with ground truth and data of ten head and neck cancer patients. The deformation vector field (DVF) accuracy was accessed using a synthetic case. The Root mean square error of the 3D canny edge (RMSECE), mutual information (MI), and feature similarity index metric (FSIM) were used to access the accuracy of LDIR on the patient data. The quality of the corresponding deformed contours was verified by an attending physician. Results: The resulting 90 percentile DVF error for the synthetic case was within 5.63mm for the original demons algorithm, 2.84mm for intensity correction alone, 2.45mm using controlpoints without intensity correction, and 1.48 mm for the LDIR algorithm. For the five patients the mean RMSECE of the original CT, Demons deformed CT, intensity corrected Demons CT, control-point stabilized deformed CT, and LDIR CT was 0.24, 0.26, 0.20, 0.20, and 0.16 respectively. Conclusion: LDIR is accurate in the presence of multimodal intensity mismatch and CBCT noise contamination. Since LDIR is GPU based it can be implemented with minimal additional strain on clinical resources. This project has been supported by a CPRIT individual investigator award RP11032
[en] An overview of the theory and techniques of radiometric thermometry is presented. The characteristics of thermal radiators (targets) are discussed along with surface roughness and oxidation effects, fresnel reflection and subsurface effects in dielectrics. The effects of the optical medium between the radiating target and the radiation thermometer are characterized including atmospheric effects, ambient temperature and dust environment effects and the influence of measurement windows. The optical and photodetection components of radiation thermometers are described and techniques for the correction of emissivity effects are addressed
[en] Possible sources of systematic error in solar Doppler rotational velocities are examined. Scattered light is shown to affect the Mount Wilson solar rotation results, but this effect is not enough to bring the spectroscopic results in coincidence with the sunspot rotation. Interference fringes at the spectrograph focus at Mount Wilson have in two intervals affected the rotation results. It has been possible to correlate this error with temperature and thus correct for it. A misalignment between the entrance and exit slits is a possible source of error, but for the Mount Wilson slit configuration the amplitude of this effect is negligibly small. Rapid scanning of the solar image also produces no measurable effect. (orig.)
[en] We investigate the effects of the saturation boundary on small-x evolution at the next-to-leading order accuracy and beyond. We demonstrate that the instabilities of the next-to-leading order BFKL evolution are not cured by the presence of the nonlinear saturation effects, and a resummation of the higher order corrections is therefore needed for the nonlinear evolution. The renormalization group improved resummed equation in the presence of the saturation boundary is investigated, and the corresponding saturation scale is extracted. A significant reduction of the saturation scale is found, and we observe that the onset of the saturation corrections is delayed to higher rapidities. This seems to be related to the characteristic feature of the resummed splitting function which at moderately small values of x possesses a minimum.