SAFETY PATROL: MECHANISMS FOR IMPROVING EMERGENCY RESPONSE TIMES

To equip first responders with critical, time-sensitive information and accelerate emergency services response times, various solutions are provided herein through several techniques. Under a first technique, after an emergency event such as a gunshot is either automatically detected by a camera or manually initiated by a user, or when a dangerous object such as a gun is detected by a camera, a network may react by associating the source of the dangerous event or object with a person based on proximity data; identifying the physical characteristics of the person (such as height, hair color, clothing, visible tattoos, etc.); attaching such characteristics as textual metadata; and then transmitting that metadata to first responders. A second technique automatically develops a radio frequency (RF) signature profile of a person of interest (from RF signals emitted by devices carried by the person), associates that profile to the person, and leverages that profile to track the person as they move throughout a building or campus, allowing a user to look back in time (to, for example, identify where a person came from and how they entered a building) by tracking the RF profile over time. The above-described data is extremely important during any ongoing emergency and equips first responders with critical information which only a network can provide

Spectral properties of the X-ray binary pulsar LMC X-4 during different intensity states

We present spectral variations of the binary X-ray pulsar LMC X-4 observed with the RXTE/PCA during different phases of its 30.5 day long third period. Only out of eclipse data were used for this study. The 3-25 keV spectrum, modeled with high energy cut-off power-law and iron line emission is found to show strong dependence on the intensity state. Correlations between the Fe line emission flux and different parameters of the continuum are presented here.Comment: 4 pages, 4 figure

Seasonal variations of glaciochemical, isotopic and stratigraphic properties in Siple Dome (Antarctica) surface snow

Six snow-pit records recovered from Siple Dome, West Antarctica, during 1994 are used to study seasonal variations in chemical (major ion and H202), isotopic (deuterium) and physical stratigraphic properties during the 1988-94 period. Comparison of δD measurements and satellite-derived brightness temperature for the Siple Dome area suggests that most seasonal SD maxima occur within ±4 weeks of each 1 January. Several other chemical species (H2O2, non-sea-salt (nss) SO4 2-, methanesulfonic acid and NO3-) show coeval peaks with SD, together providing an accurate method for identifying summer accumulation. Sea-salt-derived species generally peak during winter/spring, but episodic input is noted throughout some years. No reliable seasonal signal is identified in species with continental sources (nssCa2+ nss Mg2+), NH4 + or nssCl-. Visible strata such as large depth-hoar layers (\u3e5 cm) are associated with summer accumulation and its metamorphosis, but smaller hoar layers and crusts are more difficult to interpret. A multi-parameter approach is found to provide the most accurate dating of these snow-pit records, and is used to determine annual layer thicknesses at each site Significant spatial accumulation variability exists on an annual basis, but mean accumulation in the sampled 10 km2 grid for the 1988-94 period is fairly uniform

Cluster Ellipticities as a Cosmological Probe

We investigate the dependence of ellipticities of clusters of galaxies on cosmological parameters using large-scale cosmological simulations. We determine cluster ellipticities out to redshift unity for LCDM models with different mean densities $\Omega_m$ and amplitudes of mass fluctuation $\sigma_{8,0}$. The mean ellipticity increases monotonically with redshift for all models. Larger values of $\sigma_{8,0}$, i.e., earlier cluster formation time, produce lower ellipticities. The dependence of ellipticity on $\Omega_m$ is relatively weak in the range $0.2 \leq \Omega_m \leq 0.5$ for high mass clusters. The mean ellipticity $\bar{e}(z)$ decreases linearly with the amplitude of fluctuations at the cluster redshift $z$, nearly independent of $\Omega_m$; on average, older clusters are more relaxed and are thus less elliptical. The distribution of ellipticities about the mean is approximated by a Gaussian, allowing a simple characterization of the evolution of ellipticity with redshift as a function of cosmological parameters. At $z=0$, the mean ellipticity of high mass clusters is approximated by $\bar{e}(z=0) = 0.248-0.069 \sigma_{8,0} + 0.013 \Omega_{m,0}$. This relation opens up the possibility that, when compared with future observations of large cluster samples, the mean cluster ellipticity and its evolution could be used as a new, independent tool to constrain cosmological parameters, especially the amplitude of mass fluctuations, $\sigma_{8,0}$.Comment: 16 pages, 4 figure

Optical and structural properties of ZnO films deposited on GaAs by pulsed laser deposition

doi:10.1063/1.373643ZnO films were synthesized on GaAs substrates at different growth conditions by pulse laser deposition. High-purity (99.999%) oxygen was used as the ambient gas. The pressure of the ambient oxygen gas for ZnO film growth was varied from 20 to 50 mTorr, and the growth temperature from 300 to 450 °C. ZnO films showed very strong bound exciton peaks located between 3.37 and 3.35 eV. The full width at half maximum of the bound exciton peak is less than 5 meV. These results indicate ZnO films on GaAs substrates can be used for optical devices such as light-emitting diodes. The other significant properties of textured ZnO films on GaAs substrates are described.This work was supported in part by University of Missouri Research Board under Grant No. RB95-061, the U.S. Army Research Office ~Research Triangle Park, N.C.! under Grant No. DAAH04-94-G-0305, and the Office of Naval Research-Electronics Division, Contract No. N00014-99-1-0288

Black Holes in Galaxy Mergers: Evolution of Quasars

Based on numerical simulations of gas-rich galaxy mergers, we discuss a model in which quasar activity is tied to the self-regulated growth of supermassive black holes in galaxies. Nuclear inflow of gas attending a galaxy collision triggers a starburst and feeds black hole growth, but for most of the duration of the starburst, the black hole is heavily obscured by surrounding gas and dust which limits the visibility of the quasar, especially at optical and UV wavelengths. Eventually, feedback energy from accretion heats the gas and expels it in a powerful wind, leaving a 'dead quasar'. Between buried and dead phases there is a window during which the galaxy would be seen as a luminous quasar. Because the black hole mass, radiative output, and distribution of obscuring gas and dust all evolve strongly with time, the duration of this phase of observable quasar activity depends on both the waveband and imposed luminosity threshold. We determine the observed and intrinsic lifetimes as a function of luminosity and frequency, and calculate observable lifetimes ~10 Myr for bright quasars in the optical B-band, in good agreement with empirical estimates and much smaller than the black hole growth timescales ~100 Myr, naturally producing a substantial population of 'buried' quasars. However, observed and intrinsic energy outputs converge in the IR and hard X-ray bands as attenuation becomes weaker and chances of observation greatly increase. We obtain the distribution of column densities along sightlines in which the quasar is seen above a given luminosity, and find that our result agrees remarkably well with observed estimates of the column density distribution from the SDSS for appropriate luminosity thresholds. (Abridged)Comment: 12 pages, 7 figures. Accepted for publication in ApJ (September 2005). Replacement with minor revisions from referee repor

Rare recessive loss-of-function methionyl-tRNA synthetase mutations presenting as a multi-organ phenotype

BACKGROUND: Methionyl-tRNA synthetase (MARS) catalyzes the ligation of methionine to its cognate transfer RNA and therefore plays an essential role in protein biosynthesis. METHODS: We used exome sequencing, aminoacylation assays, homology modeling, and immuno-isolation of transfected MARS to identify and characterize mutations in the methionyl-tRNA synthetase gene (MARS) in an infant with an unexplained multi-organ phenotype. RESULTS: We identified compound heterozygous mutations (F370L and I523T) in highly conserved regions of MARS. The parents were each heterozygous for one of the mutations. Aminoacylation assays documented that the F370L and I523T MARS mutants had 18 ± 6% and 16 ± 6%, respectively, of wild-type activity. Homology modeling of the human MARS sequence with the structure of E. coli MARS showed that the F370L and I523T mutations are in close proximity to each other, with residue I523 located in the methionine binding pocket. We found that the F370L and I523T mutations did not affect the association of MARS with the multisynthetase complex. CONCLUSION: This infant expands the catalogue of inherited human diseases caused by mutations in aminoacyl-tRNA synthetase genes

Ariel - Volume 10 Number 3

Executive Editors Madalyn Schaefgen David Reich Business Manager David Reich News Editors Medical College Edward Zurad CAHS John Guardiani World Mark Zwanger Features Editors Meg Trexler Jim O\u27Brien Editorials Editor Jeffrey Banyas Photography and Sports Editor Stuart Singer Commons Editor Brenda Peterso