A measurement of direct photon production in {sup 208}Pb+ {sup 208}Pb collisions at 158A GeV has been carried out in the CERN WA98 experiment. The invariant yield of direct photons in central ...collisions is extracted as a function of transverse momentum in the interval 0.5<p{sub T}<4 GeV/c . A significant direct photon signal, compared to statistical and systematical errors, is seen at p{sub T}>1.5 GeV/c . The result constitutes the first observation of direct photons in ultrarelativistic heavy-ion collisions. It could be significant for diagnosis of quark-gluon-plasma formation.
Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body ...correlation has been found as expected for a mainly chaotic and symmetric source.
In dentistry, mechanical articulators with which mandibular movements can be reproduced in dentals casts play a major role. Commonly used semiadjustable articulators, however, have major limitations: ...On the one hand, the movement of the mandible is not reproduced exactly, on the other, they do not provide time-related information on jaw movement. Both problems can be solved by replacing the mechanical articulator by a digital simulation ("virtual articulator") based on digitized plaster casts and electronically recorded masticatory movements. We present a system for the 3D measurement of plaster casts in a skull-related, anatomical coordinate system using the fringe projection technique, and electronically recorded condylar movements. Using numerical algorithms, the contacts between upper and low jaw, and the angle of rotation of the temporomandibular joint can be computed for each movement in dynamic occlusion. Taking the data recorded from a patient as an example, the influence of the accuracy of the digitization of plaster casts on the computation of the rotation of the temporomandibular joint is discussed in relation to the anatomy of the masticatory apparatus.
Statement of problem. The analysis of occlusal contacts on mounted diagnostic casts is an important task in prosthetic diagnostics. However, it is still restricted mainly to qualitative aspects ...because existing measuring techniques fail to provide 3-dimensional data for more than a few single points in acceptable time. Purpose. The aim of this study was to develop a method for quantifying occlusal contacts and paths by using anatomically oriented diagnostic casts and to design the method to allow fast acquisition of digital 3-dimensional coordinates. Material and methods. Plaster casts with color-marked contacts were digitized optically with a profilometric system based on the fringe projection technique. Digital camera images taken simultaneously were used to define the contact areas by marking them either manually or automatically with the help of image-processing routines. Three-dimensional coordinates were determined by finding the corresponding points within the profilometric data set. Results. Color-marked contact areas on diagnostic casts were successfully digitized with a computer-controlled, automatic setup in approximately 30seconds. The accuracy of the acquired 3-dimensional data was estimated to be better than 60 μm in lateral and 30 μm in height resolution. The data set was visualized and evaluated in a skullrelated coordinate system. Summary. This study verified the use of a new tool to quantify color-marked occlusal contacts on diagnostic casts in terms of spatial coordinates. The resulting digital data may be stored easily and analyzed numerically as well as visualized 3-dimensionally with computer graphic equipment. Because the anatomic orientation of the casts is maintained throughout the measurement process, it is possible to compare the data with electronically registered condyle paths and therefore to investigate, for example, their relation to the corresponding guidance paths of the frontal teeth and the canines in dynamic occlusion. (J Prosthet Dent 2001;85:156-61.)
An event-by-event analysis of the azimuthal angular correlation with respect to the reaction plane has been carried out for
K
+ and
π
+ emission near mid-rapidity in 158
A·GeV Pb + Pb collisions. In ...semi-central collisions,
K
+ mesons are found to be preferentially emitted out of the reaction plane, while
π
+ mesons are emitted in the reaction plane. The results suggest that the kaon emission is influenced by in-medium potential effects in addition to collective flow effects.
Electronic speckle pattern interferometry (ESPI) is a well-established tool for non-destructive testing. It allows the quantitative determination of surface deformations and micro-movements with a ...sub-micrometer resolution. In the case of objects which are extended in depth, however, the evaluation and interpretation of the resulting correlation fringe patterns can be affected by perspective image distortions as well as by a varying image size. In this paper a method for combination of ESPI with a photogrammetric 3D coordinate measurement is presented. In this way, interferogram data are precisely allocated in 3D-space. Furthermore, it is possible to take into account a spatially varying sensitivity vector. The utilizability of the method is demonstrated by a deformation measurement on a stone sculpture.
Im Kiefer-Gesichts-Bereich ist die Beurteilung von Narben hinsichtlich ihrer Ästhetik von immenser Bedeutung. Ziel unserer prospektiven Untersuchungen war es, verschiedene Methoden zu dieser ...Beurteilung hinsichtlich ihrer Objektivität und Validität zu überprüfen. 3 Monate postoperativ wurden 45 Patienten mit Eingriffen im Gesichtsbereich nachuntersucht. Dabei wurde die Ästhetik der Narbe durch den Patienten selbst, aber auch von 3 Fachkollegen beurteilt. Zusätzlich wurden das Oberflächenrelief mittels der optischen Profilometrie bestimmt und eine Farbanalyse anhand des RGB- und HSV-Farbmodells durchgeführt. Während der Rotanteil im Narbenbereich überraschenderweise keinerlei Übereinstimmung mit der Bewertung durch die Fachkollegen aufwies, zeigte der Farbton (H) im HSV-Modell eine hochsignifikante Korrelation. Die Messung des Oberflächenreliefs war eher für die Selbstbeurteilung der Patienten von Bedeutung. Mit der Bestimmung des Farbtons (H) im HSV-Modell steht eine objektive und reliable Messmethode zur Bewertung von Narben hinsichtlich der Ästhetik zur Verfügung. Cosmetic outcome of surgical treatment in the facial region is influenced by the appearance of the scar. The purpose of this investigation was to evaluate the objectivity and validity of various methods for the assessment of scars. 45 patients undergoing facial surgery were examined three months after surgery. Three maxillofacial surgeons evaluated the wounds in a blinded manner using a visual analog scale (VAS). The patients also used the VAS for evaluation of their own scar. The surface of the scars was also measured by optical profilometry. Finally, the colour of the scars was analysed using both the RGB colour model and the HSV colour model. Interestingly, there was no significant correlation between the values of R (red) as assessed by the three surgeons. However, there was a very strong correlation between the values of H (hue) as assessed by the three raters. The appearance of the surface was more important in the patients' evaluation than in the raters' assessment. The hue of a scar as measured in terms of the H value in the HSV colour model is an objective and reliable measure for assessing the cosmetic outcome of facial surgery.PUBLICATION ABSTRACT
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