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Test Object (test + object)
Selected AbstractsFrequency shifting and pulse shaping with photonic-crystal fibers for coherent nonlinear spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 6 2006Ya. M. Linik Abstract The frequency-shifted and pulse-shaped output of photonic-crystal fibers (PCFs) pumped by amplified femtosecond Cr:forsterite laser pulses is employed for frequency- and time-resolved four-wave mixing (FWM) spectroscopy. Cross-correlation frequency-resolved optically gated laser-induced grating (LIG) technique is applied for the characterization of the pulse-shaped blue-shifted PCF output. The light pulses produced in the PCF are combined with the second-harmonic output of the Cr:forsterite laser, to probe a doublet of Raman resonances in the nonlinear response of a test object by means of coherent anti-Stokes Raman scattering (CARS). Copyright © 2006 John Wiley & Sons, Ltd. [source] Wissenschaftliche Photographie als visuelle Kultur.BERICHTE ZUR WISSENSCHAFTSGESCHICHTE, Issue 3 2005Die Erforschung und Dokumentation von Spektren Abstract This paper discusses facets of 19th-century scientific photography as a visual culture. The example of spectral research and documentation is particularly well suited, because prismatically diffracted light from the sun or from luminous gases was one of the most frequently examined phenomena of that century. The results were significant not only for physics but also for analytical chemistry and astrophysics. The spectrum also served as an ideal test object for checking the effectiveness of a wide array of photochemically sensitizable surfaces to the various color regions. Scientific photography became the most important experimental technique in the infrared and ultraviolet. H. A. Rowland's spectrum charts are discussed as an example of the transition from comprehensiveness in documentation to fetishism. The discussion of the Lippmann process, one of the first methods of color photography, addresses the associated training of the eye. Issues of authenticity and the much averred ,mechanical objectivity" are raised with regard to retouching. The overriding theme of visual science cultures leads furthermore to unanticipated interdependencies with other scientific fields, such as geography, and draws the importance of practitioners into the foreground. [source] Load force during manual transport in Parkinson's diseaseACTA NEUROLOGICA SCANDINAVICA, Issue 6 2004X. Guo Objectives , To search for a physiological method for the measurement of upper extremity dexterity during activities of daily life in Parkinson's disease (PD). Materials and methods , We examined load force output during manual transport in seven patients with PD and 10 healthy controls. PD patients were measured in both the non-medicated and medicated states. The test movement included two continuous sub-movements: an upward-forward transport of an object from the table to the stand, and a downward-backward transport of the object from the stand to the table. Hand movements were recorded using an optoelectronic camera, and load force was measured using a force sensor installed in the test object. Results , Compared with the controls, PD patients had a different pattern of load force output characterized by slower force development and release, lower peak force, and less dynamic force generation during movement. After medication, the speed of force development and the level of peak force increased in the patients. Conclusions , These findings suggest that PD impairs the production of preprogrammed movements. The movements observed in the PD patients may result from compensatory strategies relying more on feedback mechanisms. [source] Two-point dixon fat,water separation: Improving reliability and accuracy in phase correction algorithmsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2008Maria A. Schmidt PhD Abstract Purpose To propose an advanced phase-correction region-growing algorithm for two-point fat,water separation suitable for parotid assessment, and to evaluate the general performance of phase-correction algorithms. Materials and Methods Two region-growing algorithms were evaluated in test objects and in head images: the original phase-correction algorithm (OPC) and the advanced phase-correction algorithm with voxel size manipulation (VSM) which includes: 1) starting the region-growing process from images of lower resolution and subsequently stepping toward the original matrix size, and 2) limiting the use of low-pass filters to fat,water interfaces with partial volume effects Results Fundamental problems relate to biological tissue spectrum being poorly approximated by two discrete peaks for fat and water. The VSM algorithm was shown to be less noise-sensitive, faster, and to produce a better approximation for the field inhomogeneity map. In head images (6 volunteers, 10 slices each) 43 errors were found with the OPC algorithm and only 6 errors with the VSM algorithm. Only the OPC algorithm produced errors surrounding the parotids (10 errors). Conclusion The VSM algorithm provides a more accurate and less noise-sensitive fat,water separation. This highly significant performance improvement allows the application of phase-correction algorithms to a wider range of clinical applications. J. Magn. Reson. Imaging 2008. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||