96 research outputs found

    Sufficient Conditions For An Optimal Solution To The Problem Of Scheduling A Bottleneck Of An N-Stage Process

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    This paper discusses the application of an algorithm for scheduling the bottleneck of an n-stage process involving multiple products to information systems development.  The algorithm is presented along with Pence’s Theorem, conditions sufficient for an optimal solution are presented, and the application of this algorithm and theorem to the development of information systems

    The IS Undergraduate Curriculum: Predicting Student Outcomes In An Upper Division Programming Course

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    Academic performance of students is a primary factor in student attrition.  Being able to reliably predict academic success would facilitate improved advising for academic program and course selection.  This study examines several predictor variables and assesses their value in predicting course performance in an upper division computer programming course in an undergraduate business-based Information Systems (IS) degree program

    An Exploration Of The Impact Of Online Delivery In Prerequisite Courses On CIS Majors Course Sequence

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    On-line courses have become an important component of the delivery of courses in all areas of education. The validity of online delivery is challenged if Web students perform poorly in subsequent major courses. This paper investigates the level of success, failure, potential, and limitation of on-line delivery in the CIS area at MSCD. The result of this research will provide a framework for developing a methodology for this kind of study, allowing academic institutions to evaluate the success and utility of online courses

    Examining the Properties of Low-Luminosity Hosts of Type Ia Supernovae from ASAS-SN

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    We present a spectroscopic analysis of 44 low-luminosity host galaxies of Type Ia supernovae (SNe Ia) detected by the All-Sky Automated Survey for Supernovae (ASAS-SN), using the emission lines to measure metallicities and star formation rates. We find that although the star formation activity of our sample is representative of general galaxies, there is some evidence that the lowest-mass SN Ia host galaxies (log(M⋆/M⊙M_\star/M_\odot)<8<8) in our sample have high metallicities compared to general galaxies of similar masses. We also identify a subset of 5 galaxies with particularly high metallicities. This highlights the need for spectroscopic analysis of more low-luminosity, low-mass SN Ia host galaxies to test the robustness of these conclusions and their potential impact on our understanding of SN Ia progenitors.Comment: 13 pages, 7 figures, 2 tables. Submitted to ApJ. Full versions of the tables in the paper are available in machine-readable format as ancillary file

    UBVRIz Light Curves of 51 Type II Supernovae

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    We present a compilation of UBV RIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986 to 2003: the Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being thus shorter (longer) for larger (smaller) s values.Comment: 110 pages, 9 Figures, 6 Tables, accepted in A

    Design, construction, and characterization of a compact DD neutron generator designed for 40Ar/39Ar geochronology

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    A next-generation, high-flux DD neutron generator has been designed, commissioned, and characterized, and is now operational in a new facility at the University of California Berkeley. The generator, originally designed for 40Ar/39Ar dating of geological materials, has since served numerous additional applications, including medical isotope production studies, with others planned for the near future. In this work, we present an overview of the High Flux Neutron Generator (HFNG) which includes a variety of simulations, analytical models, and experimental validation of results. Extensive analysis was performed in order to characterize the neutron yield, flux, and energy distribution at specific locations where samples may be loaded for irradiation. A notable design feature of the HFNG is the possibility for sample irradiation internal to the cathode, just 8 mm away from the neutron production site, thus maximizing the neutron flux (n/cm2/s). The generator's maximum neutron flux at this irradiation position is 2.58e7 n/cm2/s +/- 5% (approximately 3e8 n/s total yield) as measured via activation of small natural indium foils. However, future development is aimed at achieving an order of magnitude increase in flux. Additionally, the deuterium ion beam optics were optimized by simulations for various extraction configurations in order to achieve a uniform neutron flux distribution and an acceptable heat load. Finally, experiments were performed in order to benchmark the modeling and characterization of the HFNG.Comment: 31 pages, 20 figure

    Relationships between adverse childhood experiences and adult mental well-being: results from an English national household survey.

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    BACKGROUND: Individuals' childhood experiences can strongly influence their future health and well-being. Adverse childhood experiences (ACEs) such as abuse and dysfunctional home environments show strong cumulative relationships with physical and mental illness yet less is known about their effects on mental well-being in the general population. METHODS: A nationally representative household survey of English adults (n = 3,885) measuring current mental well-being (Short Edinburgh-Warwick Mental Well-being Scale SWEMWBS) and life satisfaction and retrospective exposure to nine ACEs. RESULTS: Almost half of participants (46.4 %) had suffered at least one ACE and 8.3 % had suffered four or more. Adjusted odds ratios (AORs) for low life satisfaction and low mental well-being increased with the number of ACEs. AORs for low ratings of all individual SWEMWBS components also increased with ACE count, particularly never or rarely feeling close to others. Of individual ACEs, growing up in a household affected by mental illness and suffering sexual abuse had the most relationships with markers of mental well-being. CONCLUSIONS: Childhood adversity has a strong cumulative relationship with adult mental well-being. Comprehensive mental health strategies should incorporate interventions to prevent ACEs and moderate their impacts from the very earliest stages of life

    Translational pharmacology of an inhaled small molecule αvβ6 integrin inhibitor for idiopathic pulmonary fibrosis

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    The αvβ6 integrin plays a key role in the activation of transforming growth factor-β (TGFβ), a pro-fibrotic mediator that is pivotal to the development of idiopathic pulmonary fibrosis (IPF). We identified a selective small molecule αvβ6 RGD-mimetic, GSK3008348, and profiled it in a range of disease relevant pre-clinical systems. To understand the relationship between target engagement and inhibition of fibrosis, we measured pharmacodynamic and diseaserelated end points. Here we report, GSK3008348 binds to αvβ6 with high affinity in human IPF lung and reduces downstream pro-fibrotic TGFβ signaling to normal levels. In human lung epithelial cells, GSK3008348 induces rapid internalization and lysosomal degradation of the αvβ6 integrin. In the murine bleomycin-induced lung fibrosis model, GSK3008348 engages αvβ6, induces prolonged inhibition of TGFβ signaling and reduces lung collagen deposition and serum C3M, a marker of IPF disease progression. These studies highlight the potential of inhaled GSK3008348 as an anti-fibrotic therapy

    Carnegie Supernova Project-I and -II: Measurements of H0H_0 using Cepheid, TRGB, and SBF Distance Calibration to Type Ia Supernovae

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    We present an analysis of Type Ia Supernovae (SNe~Ia) from both the Carnegie Supernova Project~I (CSP-I) and II (CSP-II), and extend the Hubble diagram from the optical to the near-infrared wavelengths (uBgVriYJHuBgVriYJH). We calculate the Hubble constant, H0H_0, using various distance calibrators: Cepheids, Tip of the Red Giant Branch (TRGB), and Surface Brightness Fluctuations (SBF). Combining all methods of calibrations, we derive $\rm H_0=71.76 \pm 0.58 \ (stat) \pm 1.19 \ (sys) \ km \ s^{-1} \ Mpc^{-1}from from B−band,and-band, and \rm H_0=73.22 \pm 0.68 \ (stat) \pm 1.28 \ (sys) \ km \ s^{-1} \ Mpc^{-1}from from H−band.ByassigningequalweighttotheCepheid,TRGB,andSBFcalibrators,wederivethesystematicerrorsrequiredforconsistencyinthefirstrungofthedistanceladder,resultinginasystematicerrorof-band. By assigning equal weight to the Cepheid, TRGB, and SBF calibrators, we derive the systematic errors required for consistency in the first rung of the distance ladder, resulting in a systematic error of 1.2\sim 1.3 \rm \ km \ s^{-1} \ Mpc^{-1}in in H_0.Asaresult,relativetothestatistics−onlyuncertainty,thetensionbetweenthelate−time. As a result, relative to the statistics-only uncertainty, the tension between the late-time H_0wederivebycombiningthevariousdistancecalibratorsandtheearly−time we derive by combining the various distance calibrators and the early-time H_0fromtheCosmicMicrowaveBackgroundisreduced.ThehighestprecisioninSN Ialuminosityisfoundinthe from the Cosmic Microwave Background is reduced. The highest precision in SN~Ia luminosity is found in the Yband( band (0.12\pm0.01mag),asdefinedbytheintrinsicscatter( mag), as defined by the intrinsic scatter (\sigma_{int}$). We revisit SN~Ia Hubble residual-host mass correlations and recover previous results that these correlations do not change significantly between the optical and the near-infrared wavelengths. Finally, SNe~Ia that explode beyond 10 kpc from their host centers exhibit smaller dispersion in their luminosity, confirming our earlier findings. Reduced effect of dust in the outskirt of hosts may be responsible for this effect.Comment: Revised calculations are made. Will be resubmitted to Ap
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