Emory University

Atlanta, GA, United States

Departments View all

Department of Pediatrics
4,461
Total Impact Points
110
Members
Department of Psychiatry and Behavioral Sciences
6,574
Total Impact Points
88
Members
Department of Pathology and Laboratory Medicine
7,360
Total Impact Points
83
Members

Publication History View all

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Both grain surface and gas phase chemistry have been invoked to explain the disparate relative abundances of methyl formate and its structural isomers acetic acid and glycolaldehyde in the Sgr B2(N) star-forming region. While a network of grain surface chemistry involving radical–radical reactions during the warm-up phase of a hot core is the most chemically viable option proposed to date, neither qualitative nor quantitative agreement between modeling and observation has yet been obtained. In this study, we seek to test additional grain surface and gas phase processes to further investigate methyl formate-related chemistry by implementing several modifications to the Ohio State University gas/grain chemical network. We added two new gas phase chemical pathways leading to methyl formate, one involving an exothermic, barrierless reaction of protonated methanol with neutral formic acid; and one involving the reaction of protonated formic acid with neutral methanol to form both the cis and trans forms of protonated methyl formate. In addition to these gas phase processes, we have also investigated whether the relative product branching ratios for methanol photodissociation on grains influence the relative abundances of methyl formate and its structural isomers. We find that while the new gas phase formation pathways do not alter the relative abundances of methyl formate and its structural isomers, changes in the photodissociation branching ratios and adjustment of the overall timescale for warm-up can be used to explain their relative ratios in Sgr B2(N).
    The Astrophysical Journal 09/2015; 728:71-9.
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present the second output-sensitive skyline computation algorithm which is faster than the only existing output-sensitive skyline computation algorithm [1] in worst case because our algorithm does not rely on the existence of a linear time procedure for finding medians.
    Information Processing Letters 12/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: In multi-regional trials, the underlying overall and region-specific accrual rates often do not hold constant over time and different regions could have different start-up times, which combined with initial jump in accrual within each region often leads to a discontinuous overall accrual rate, and these issues associated with multi-regional trials have not been adequately investigated. In this paper, we clarify the implication of the multi-regional nature on modeling and prediction of accrual in clinical trials and investigate a Bayesian approach for accrual modeling and prediction, which models region-specific accrual using a nonhomogeneous Poisson process and allows the underlying Poisson rate in each region to vary over time. The proposed approach can accommodate staggered start-up times and different initial accrual rates across regions/centers. Our numerical studies show that the proposed method improves accuracy and precision of accrual prediction compared to existing methods including the nonhomogeneous Poisson process model that does not model region-specific accrual.
    Statistical methods in medical research. 11/2014;

Information

  • Address
    201 Dowman Drive, 30322, Atlanta, GA, United States
  • Head of Institution
    James Wagner
  • Website
    www.emory.edu
  • Phone
    404.727.6123
Information provided on this web page is aggregated encyclopedic and bibliographical information relating to the named institution. Information provided is not approved by the institution itself. The institution’s logo (and/or other graphical identification, such as a coat of arms) is used only to identify the institution in a nominal way. Under certain jurisdictions it may be property of the institution.

2744 Members View all

Top Collaborating Institutions

Collaborations

This map visualizes which other institutions researchers from Emory University have collaborated with.

Rg score distribution

See how the RG Scores of researchers from Emory University are distributed.