1-1.4 Micron Spectral Atlas of Stars

We present a catalog of J-band (1.08 um to 1.35 um) stellar spectra at low resolution (R ~ 400). The targets consist of 105 stars ranging in spectral type from O9.5 to M7 and luminosity classes I through V. The relatively featureless spectra of hot stars, earlier than A4, can be used to remove the atmospheric features which dominate ground-based J-band spectroscopy. We measure equivalent widths for three absorption lines and nine blended features which we identify in the spectra. Using detailed comparison with higher resolution spectra, we demonstrate that low resolution data can be used for stellar classification, since several features depend on the effective temperature and gravity. For example The CN index (1.096 - 1.104 um) decreases with temperature, but the strength of a blended feature at 1.28 um (consisting of primarily P beta) increases. The slope of a star's spectrum can also be used to estimate its effective temperature. The luminosity class of a star correlates with the ratio of the Mg I (1.1831 um) line to a blend of several species at 1.16 um. Using these indicators, a star can be classified to within several subclasses. Fifteen stars with particularly high and low metal abundances are included in the catalog and some spectral dependence on metal abundance is also found.Comment: 35 pages, 10 figures (3a-e are in gif format. For complete high resolution figures, go to http://www.astro.ucla.edu/~malkan/newjspec/) ; Accepted for published in ApJS; For associated spectra files, see http://www.astro.ucla.edu/~malkan/newjspec

Experimental Outlook for the Pentaquark

A critical look is taken at both positive and null evidence for the $\Theta^+$ pentaquark. Potential problems with experiments will be discussed and the question of what conclusion can be drawn from both the positive and the null results is examined. First the question of existence of the $\Theta^+$ pentaquark is considered, followed by a discussion of new experiments that are either planned or in progress to answer questions about its mass, width and isospin. Finally, indirect evidence for the parity of the $\Theta^+$ is examined, and suggestions for experiments to measure its parity directly are given.Comment: MESON2004 conference proceedings, 10 pages, 1 figur

A general numerical analysis program for the superconducting quasiparticle mixer

A user-oriented computer program SISCAP (SIS Computer Analysis Program) for analyzing SIS mixers is described. The program allows arbitrary impedance terminations to be specified at all LO harmonics and sideband frequencies. It is therefore able to treat a much more general class of SIS mixers than the widely used three-frequency analysis, for which the harmonics are assumed to be short-circuited. An additional program, GETCHI, provides the necessary input data to program SISCAP. The SISCAP program performs a nonlinear analysis to determine the SIS junction voltage waveform produced by the local oscillator. The quantum theory of mixing is used in its most general form, treating the large signal properties of the mixer in the time domain. A small signal linear analysis is then used to find the conversion loss and port impedances. The noise analysis includes thermal noise from the termination resistances and shot noise from the periodic LO current. Quantum noise is not considered. Many aspects of the program have been adequately verified and found accurate

The preservation of quartz grain surface textures following vehicle fire and their use in forensic enquiry

During a terrorist trial, dispute arose as to whether the temperature produced in a car fire was sufficient to destroy quartz grain surface textures. A series of seven sequential experiments showed that the temperature for quartz surface texture modification/destruction and the production of vugs, vesicles and glassy precipitation ('snowdrifting') occurred at 1200 degrees C under normal atmospheric conditions. By adding a number of man-made and natural substances, it was found that only the presence of salts depressed this modification temperature (to 900 degrees C). Experiments to determine the temperature of fire in a car indicated that the maximum temperature produced under natural conditions (810 degrees C) was insufficient to affect the quartz grain Surface textures. These results confirm the use of surface texture analysis of quartz grains recovered from the remains of cars Subjected to fire and their use as a forensic indicator. (C) 2008 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved

The clinical application of PET/CT: a contemporary review

The combination of positron emission tomography (PET) scanners and x-ray computed tomography (CT) scanners into a single PET/CT scanner has resulted in vast improvements in the diagnosis of disease, particularly in the field of oncology. A decade on from the publication of the details of the first PET/CT scanner, we review the technology and applications of the modality. We examine the design aspects of combining two different imaging types into a single scanner, and the artefacts produced such as attenuation correction, motion and CT truncation artefacts. The article also provides a discussion and literature review of the applications of PET/CT to date, covering detection of tumours, radiotherapy treatment planning, patient management, and applications external to the field of oncology

Sommerfeld's image method in the calculation of van der Waals forces

We show how the image method can be used together with a recent method developed by C. Eberlein and R. Zietal to obtain the dispersive van der Waals interaction between an atom and a perfectly conducting surface of arbitrary shape. We discuss in detail the case of an atom and a semi- infinite conducting plane. In order to employ the above procedure to this problem it is necessary to use the ingenious image method introduced by Sommerfeld more than one century ago, which is a generalization of the standard procedure. Finally, we briefly discuss other interesting situations that can also be treated by the joint use of Sommerfeld's image technique and Eberlein-Zietal method.Comment: To appear in the proceedings of Conference on Quantum Field Theory under the Influence of External Conditions (QFEXT11

REASSURE: A Self-contained Mechanism for Healing Software Using Rescue Points

Software errors are frequently responsible for the limited availability of Internet Services, loss of data, and many security compromises. Self-healing using rescue points (RPs) is a mechanism that can be used to recover software from unforeseen errors until a more permanent remedy, like a patch or update, is available. We present REASSURE, a self-contained mechanism for recovering from such errors using RPs. Essentially, RPs are existing code locations that handle certain anticipated errors in the target application, usually by returning an error code. REASSURE enables the use of these locations to also handle unexpected faults. This is achieved by rolling back execution to a RP when a fault occurs, returning a valid error code, and enabling the application to gracefully handle the unexpected error itself. REASSURE can be applied on already running applications, while disabling and removing it is equally facile. We tested REASSURE with various applications, including the MySQL and Apache servers, and show that it allows them to successfully recover from errors, while incurring moderate overhead between 1% and 115%. We also show that even under very adverse conditions, like their continuous bombardment with errors, REASSURE protected applications remain operational