3,502 research outputs found

    Book Review: Neither Kin nor Kind: The Peculiar Ties that Bond Organ Donors, their Families and Transplant Recipients

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    Reviewing Strange Harvest: Organ Transplants, Denatured Bodies, and the Transformed Self by Leslie A. Sharp, Berkeley, Cal., University of California Press, 2006

    Behavioral Mapless Navigation Using Rings

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    This paper presents work on the development and implementation of a novel approach to robotic navigation. In this system, map-building and localization for obstacle avoidance are discarded in favor of moment-by-moment behavioral processing of the sonar sensor data. To accomplish this, we developed a network of behaviors that communicate through the passing of rings, data structures that are similar in form to the sonar data itself and express the decisions of each behavior. Through the use of these rings, behaviors can moderate each other, conflicting impulses can be mediated, and designers can easily connect modules to create complex emergent navigational techniques. We discuss the development of a number of these modules and their successful use as a navigation system in the Trinity omnidirectional robot

    Drinking During the Week? Alcohol and Religion among College Students

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    Alcohol use among college students has been correlated with academic performance, major choice, and risky behaviors, such as impaired driving and high-risk sexual encounters. As college students matriculate, they learn to make decisions about who they are now, and who they will become in the future; decisions that include choices about religion. The study explored the differences in religious self-identification and alcohol use among students who identified themselves as unsure of their religious beliefs, those who were spiritual, and those who were religious; results found that students who self-identified as religious were less likely to drink alcohol within the past month

    Drinking During the Week? Alcohol Use and Religion among College Students

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    Alcohol use among college students has been correlated with academic performance, major choice, and risky behaviors, such as impaired driving and high-risk sexual encounters. As college students matriculate, they learn to make decisions about who they are now, and who they will become in the future; decisions that include choices about religion. The study explored the differences in religious self-identification and alcohol use among students who identified themselves as unsure of their religious beliefs, those who were spiritual, and those who were religious; results found that students who self-identified as religious were less likely to drink alcohol within the past month.

    Verifying the Safety of a Flight-Critical System

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    This paper describes our work on demonstrating verification technologies on a flight-critical system of realistic functionality, size, and complexity. Our work targeted a commercial aircraft control system named Transport Class Model (TCM), and involved several stages: formalizing and disambiguating requirements in collaboration with do- main experts; processing models for their use by formal verification tools; applying compositional techniques at the architectural and component level to scale verification. Performed in the context of a major NASA milestone, this study of formal verification in practice is one of the most challenging that our group has performed, and it took several person months to complete it. This paper describes the methodology that we followed and the lessons that we learned.Comment: 17 pages, 5 figure

    The hard to soft spectral transition in LMXBs - affected by recondensation of gas into an inner disk

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    Soft and hard spectral states of X-ray transient sources reflect two modes of accretion, accretion via a geometrically thin, optically thick disk or an advection-dominated accretion flow (ADAF). The luminosity at transition between these two states seems to vary from source to source, or even for the same source during different outbursts, as observed for GX 339-4. We investigate how the existence of an inner weak disk in the hard state affects the transition luminosity. We evaluate the structure of the corona above an outer truncated disk and the resulting disk evaporation rate for different irradiation. In some cases, recent observations of X-ray transients indicate the presence of an inner cool disk during the hard state. Such a disk can remain during quiescence after the last outburst as long as the luminosity does not drop to very low values (10^-4 to 10^-3 of the Eddington luminosity). Consequently, as part of the matter accretes via the inner disk, the hard irradiation is reduced. The hard irradiation is further reduced, occulted and partly reflected by the inner disk. This leads to a hard-soft transition at a lower luminosity if an inner disk exists below the ADAF. This seems to be supported by observations for GX 339-4.Comment: 9 pages, 4 figures, accepted for publication in Astronomy and Astrophysic

    A common founding clone with TP53 and PTEN mutations gives rise to a concurrent germ cell tumor and acute megakaryoblastic leukemia

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    We report the findings from a patient who presented with a concurrent mediastinal germ cell tumor (GCT) and acute myeloid leukemia (AML). Bone marrow pathology was consistent with a diagnosis of acute megakaryoblastic leukemia (AML M7), and biopsy of an anterior mediastinal mass was consistent with a nonseminomatous GCT. Prior studies have described associations between hematological malignancies, including AML M7 and nonseminomatous GCTs, and it was recently suggested that a common founding clone initiated both cancers. We performed enhanced exome sequencing on the GCT and the AML M7 from our patient to define the clonal relationship between the two cancers. We found that both samples contained somatic mutations in PTEN (C136R missense) and TP53 (R213 frameshift). The mutations in PTEN and TP53 were present at ∼100% variant allele frequency (VAF) in both tumors. In addition, we detected and validated five other shared somatic mutations. The copy-number analysis of the AML exome data revealed an amplification of Chromosome 12p. We also identified a heterozygous germline variant in FANCA (S858R), which is known to be associated with Fanconi anemia but is of uncertain significance here. In summary, our data not only support a common founding clone for these cancers but also suggest that a specific set of distinct genomic alterations (in PTEN and TP53) underlies the rare association between GCT and AML. This association is likely linked to the treatment resistance and extremely poor outcome of these patients. We cannot resolve the clonal evolution of these tumors given limitations of our data

    CASTER - a concept for a Black Hole Finder Probe based on the use of new scintillator technologies

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    The primary scientific mission of the Black Hole Finder Probe (BHFP), part of the NASA Beyond Einstein program, is to survey the local Universe for black holes over a wide range of mass and accretion rate. One approach to such a survey is a hard X-ray coded-aperture imaging mission operating in the 10--600 keV energy band, a spectral range that is considered to be especially useful in the detection of black hole sources. The development of new inorganic scintillator materials provides improved performance (for example, with regards to energy resolution and timing) that is well suited to the BHFP science requirements. Detection planes formed with these materials coupled with a new generation of readout devices represent a major advancement in the performance capabilities of scintillator-based gamma cameras. Here, we discuss the Coded Aperture Survey Telescope for Energetic Radiation (CASTER), a concept that represents a BHFP based on the use of the latest scintillator technology.Comment: 12 pages; conference paper presented at the SPIE conference "UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XIV." To be published in SPIE Conference Proceedings, vol. 589

    CASTER: a scintillator-based black hole finder probe

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    The primary scientific mission of the Black Hole Finder Probe (BHFP), part of the NASA Beyond Einstein program, is to survey the local Universe for black holes over a wide range of mass and accretion rate. One approach to such a survey is a hard X-ray coded-aperture imaging mission operating in the 10-600 keV energy band, a spectral range that is considered to be especially useful in the detection of black hole sources. The development of new inorganic scintillator materials provides improved performance (for example, with regards to energy resolution and timing) that is well suited to the BHFP science requirements. Detection planes formed with these materials coupled with a new generation of readout devices represent a major advancement in the performance capabilities of scintillator-based gamma cameras. Here, we discuss the Coded Aperture Survey Telescope for Energetic Radiation (CASTER), a concept that represents a BHFP based on the use of the latest scintillator technology

    Nuclear Magnetic Resonance and Hyperfine Structure

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    Contains reports on five research projects
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