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Creators/Authors contains: "Howard, K"

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  1. Abstract The20Ne(α,p)23Na reaction rate is important in determining the final abundances of various nuclei produced in type Ia supernovae. Previously, the ground state cross section was calculated from time reversal reaction experiments using detailed balance. The reaction rates extracted from these studies do not consider contributions from the population of excited states, and therefore, are only estimates. A resonance scan, populating both the ground and first excited states, was performed for the20Ne(α,p)23Na reaction, measuring between 2.9 and 5 MeV center of mass energies at the Nuclear Science Lab at the University of Notre Dame. Data analysis is underway and preliminary results show substantial contribution from the excited state reaction. 
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  2. null (Ed.)
    Web Browsers have storage components and external software that aid in creating an enjoyable and functioning browser experience. Web browser history, cookies, ActiveX controls, and extensions all have vulnerabilities that are exploited by hackers, websites, and the web browsers themselves. Users are putting themselves at risk for an attack on their browser, possibly even their systems if they do not take the proper actions to secure their browser and keep their information private. This paper will discuss the aspects of the web browser named above, their security issues, and what can be done to stay protected. 
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  3. null (Ed.)
  4. Abstract We use photometric redshifts and statistical background subtraction to measure stellar mass functions in galaxy group-mass (4.5 − 8 × 1013 M⊙) haloes at 1 < z < 1.5. Groups are selected from COSMOS and SXDF, based on X-ray imaging and sparse spectroscopy. Stellar mass (Mstellar) functions are computed for quiescent and star-forming galaxies separately, based on their rest-frame UVJ colours. From these we compute the quiescent fraction and quiescent fraction excess (QFE) relative to the field as a function of Mstellar. QFE increases with Mstellar, similar to more massive clusters at 1 < z < 1.5. This contrasts with the apparent separability of Mstellar and environmental factors on galaxy quiescent fractions at z ∼ 0. We then compare our results with higher mass clusters at 1 < z < 1.5 and lower redshifts. We find a strong QFE dependence on halo mass at fixed Mstellar; well fit by a logarithmic slope of d(QFE)/dlog (Mhalo) ∼ 0.24 ± 0.04 for all Mstellar and redshift bins. This dependence is in remarkably good qualitative agreement with the hydrodynamic simulation BAHAMAS, but contradicts the observed dependence of QFE on Mstellar. We interpret the results using two toy models: one where a time delay until rapid (instantaneous) quenching begins upon accretion to the main progenitor (“no pre-processing”) and one where it starts upon first becoming a satellite (“pre-processing”). Delay times appear to be halo mass dependent, with a significantly stronger dependence required without pre-processing. We conclude that our results support models in which environmental quenching begins in low-mass (<1014M⊙) haloes at z > 1. 
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