315 research outputs found

    Development of a Tool to Recreate the Mars Science Laboratory Aerothermal Environment

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    The Mars Science Laboratory will enter the Martian atmosphere in 2012 with multiple char depth sensors and in-depth thermocouples in its heatshield. The aerothermal environment experienced by MSL may be computationally recreated using the data from the sensors and a material response program, such as the Fully Implicit Ablation and Thermal (FIAT) response program, through the matching of the char depth and thermocouple predictions of the material response program to the sensor data. A tool, CHanging Inputs from the Environment of FIAT (CHIEF), was developed to iteratively change different environmental conditions such that FIAT predictions match within certain criteria applied to an external data set. The computational environment is changed by iterating on the enthalpy, pressure, or heat transfer coefficient at certain times in the trajectory. CHIEF was initially compared against arc-jet test data from the development of the MSL heatshield and then against simulated sensor data derived from design trajectories for MSL. CHIEF was able to match char depth and in-depth thermocouple temperatures within the bounds placed upon it for these cases. Further refinement of CHIEF to compare multiple time points and assign convergence criteria may improve accuracy

    Increasing Underrepresented Scientists in Cancer Research: The UCSD CURE Program

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    The Moores UCSD Cancer Center’s Continuing Umbrella of Research Experiences program aims to increase the number of underrepresented students pursuing careers in cancer research, cancer care, and health disparities research. Participants receive 8 weeks of laboratory and classroom training during the summer followed by participation in research mentors’ laboratories. Of the 82 CURE students accrued (2002 and 2008), 91% persisted in science after 1 year. Of the 63 students eligible to graduate in 2009, 7 had dropped out of college; 56 graduated. Of the graduates, 98% were science majors and 61% (34) had already matriculated to graduate or health professional schools for cancer research and clinical care careers

    The Panchromatic Hubble Andromeda Treasury. Progression of Large-Scale Star Formation across Space and Time in M31

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    We investigate the clustering of early-type stars younger than 300 Myr on galactic scales in M31. Based on the stellar photometric catalogs of the Panchromatic Hubble Andromeda Treasury program that also provides stellar parameters derived from the individual energy distributions, our analysis is focused on the young stars in three star-forming regions, located at galactocentric distances of about 5, 10, and 15 kpc, corresponding to the inner spiral arms, the ring structure, and the outer arm, respectively. We apply the two-point correlation function to our selected sample to investigate the clustering behavior of these stars across different time- and length-scales. We find that young stellar structure survives across the whole extent of M31 longer than 300 Myr. Stellar distribution in all regions appears to be self-similar, with younger stars being systematically more strongly clustered than the older, which are more dispersed. The observed clustering is interpreted as being induced by turbulence, the driving source for which is probably gravitational instabilities driven by the spiral arms, which are stronger closer to the galactic centre.Comment: 10 pages, 5 figures. To appear in "LESSONS FROM THE LOCAL GROUP - A Conference in Honour of David Block and Bruce Elmegreen" eds. Freeman, K.C., Elmegreen, B.G., Block, D.L. & Woolway, M. (Springer: New York

    PHAT Stellar Cluster Survey I. Year 1 Catalog and Integrated Photometry

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    The Panchromatic Hubble Andromeda Treasury (PHAT) survey is an on-going Hubble Space Telescope (HST) multi-cycle program to obtain high spatial resolution imaging of one-third of the M31 disk at ultraviolet through near-infrared wavelengths. In this paper, we present the first installment of the PHAT stellar cluster catalog. When completed, the PHAT cluster catalog will be among the largest and most comprehensive surveys of resolved star clusters in any galaxy. The exquisite spatial resolution achieved with HST has allowed us to identify hundreds of new clusters that were previously inaccessible with existing ground-based surveys. We identify 601 clusters in the Year 1 sample, representing more than a factor of four increase over previous catalogs within the current survey area (390 arcmin^2). This work presents results derived from the first \sim25% of the survey data; we estimate that the final sample will include \sim2500 clusters. For the Year 1 objects, we present a catalog with positions, radii, and six-band integrated photometry. Along with a general characterization of the cluster luminosities and colors, we discuss the cluster luminosity function, the cluster size distributions, and highlight a number of individually interesting clusters found in the Year 1 search.Comment: 26 pages, 22 figures, Accepted by Ap
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