5,236 research outputs found

    Resolving Architectural Mismatches of COTS Through Architectural Reconciliation

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    The integration of COTS components into a system under development entails architectural mismatches. These have been tackled, so far, at the component level, through component adaptation techniques, but they also must be tackled at an architectural level of abstraction. In this paper we propose an approach for resolving architectural mismatches, with the aid of architectural reconciliation. The approach consists of designing and subsequently reconciling two architectural models, one that is forward-engineered from the requirements and another that is reverse-engineered from the COTS-based implementation. The final reconciled model is optimally adapted both to the requirements and to the actual COTS-based implementation. The contribution of this paper lies in the application of architectural reconciliation in the context of COTS-based software development. Architectural modeling is based upon the UML 2.0 standard, while the reconciliation is performed by transforming the two models, with the help of architectural design decisions.

    Chandra Observations of Extended X-ray Emission in Arp 220

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    We resolve the extended X-ray emission from the prototypical ultraluminous infrared galaxy Arp 220. Extended, faint edge-brightened, soft X-ray lobes outside the optical galaxy are observed to a distance of 10 to 15 kpc on each side of the nuclear region. Bright plumes inside the optical isophotes coincide with the optical line emission and extend 11 kpc from end to end across the nucleus. The data for the plumes cannot be fit by a single temperature plasma, and display a range of temperatures from 0.2 to 1 keV. The plumes emerge from bright, diffuse circumnuclear emission in the inner 3 kpc centered on the Halpha peak, which is displaced from the radio nuclei. There is a close morphological correspondence between the Halpha and soft X-ray emission on all spatial scales. We interpret the plumes as a starburst-driven superwind, and discuss two interpretations of the emission from the lobes in the context of simulations of the merger dynamics of Arp 220.Comment: Accepted for publication in ApJ; see also astro-ph/0208477 (Paper 1

    Extreme Pyroconvective Updrafts During a Megafire

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    Airborne cloud radar reveals extreme wildfire updrafts (~60 m s−1) and downdrafts (~30 m s−1) rivaling those in supercell thunderstorms. These extreme vertical velocities occur through a 3-km-deep layer and below the base of a developing pyrocumulonimbus (pyroCb) cloud, which extends to the tropopause at 12 km. In situ aircraft sampling shows updrafts are linked to large temperature and moisture excesses but remain subsaturated at flight level (i.e., below cloud base). Parcel estimates using the in situ data help explain how these “hot-moist” updrafts trigger the overlying pyroCb. The extreme vertical motions observed also pose a previously undocumented aviation hazard

    Excitations in confined helium

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    We design models for helium in matrices like aerogel, Vycor or Geltech from a manifestly microscopic point of view. For that purpose, we calculate the dynamic structure function of 4He on Si substrates and between two Si walls as a function of energy, momentum transfer, and the scattering angle. The angle--averaged results are in good agreement with the neutron scattering data; the remaining differences can be attributed to the simplified model used here for the complex pore structure of the materials. A focus of the present work is the detailed identification of coexisting layer modes and bulk--like excitations, and, in the case of thick films, ripplon excitations. Involving essentially two--dimensional motion of atoms, the layer modes are sensitive to the scattering angle.Comment: Phys. Rev. B (2003, in press

    The Physical Connections Among IR QSOs, PG QSOs and Narrow-Line Seyfert 1 Galaxies

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    We study the properties of infrared-selected QSOs (IR QSOs), optically-selected QSOs (PG QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s). We compare their properties from the infrared to the optical and examine various correlations among the black hole mass, accretion rate, star formation rate and optical and infrared luminosities. We find that the infrared excess in IR QSOs is mostly in the far infrared, and their infrared spectral indices suggest that the excess emission is from low temperature dust heated by starbursts rather than AGNs. The infrared excess is therefore a useful criterion to separate the relative contributions of starbursts and AGNs. We further find a tight correlation between the star formation rate and the accretion rate of central AGNs for IR QSOs. The ratio of the star formation rate and the accretion rate is about several hundred for IR QSOs, but decreases with the central black hole mass. This shows that the tight correlation between the stellar mass and the central black hole mass is preserved in massive starbursts during violent mergers. We suggest that the higher Eddington ratios of NLS1s and IR QSOs imply that they are in the early stage of evolution toward classical Seyfert 1's and QSOs, respectively.Comment: 32 pages, 6 figures, accepted by Ap

    Testing the single-pass VOC removal efficiency of an active green wall using methyl ethyl ketone (MEK)

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    © 2017, The Author(s). In recent years, research into the efficacy of indoor air biofiltration mechanisms, notably living green walls, has become more prevalent. Whilst green walls are often utilised within the built environment for their biophilic effects, there is little evidence demonstrating the efficacy of active green wall biofiltration for the removal of volatile organic compounds (VOCs) at concentrations found within an interior environment. The current work describes a novel approach to quantifying the VOC removal effectiveness by an active living green wall, which uses a mechanical system to force air through the substrate and plant foliage. After developing a single-pass efficiency protocol to understand the immediate effects of the system, the active green wall was installed into a 30-m3 chamber representative of a single room and presented with the contaminant 2-butanone (methyl ethyl ketone; MEK), a VOC commonly found in interior environments through its use in textile and plastic manufacture. Chamber inlet levels of MEK remained steady at 33.91 ± 0.541 ppbv. Utilising a forced-air system to draw the contaminated air through a green wall based on a soil-less growing medium containing activated carbon, the combined effects of substrate media and botanical component within the biofiltration system showed statistically significant VOC reduction, averaging 57% single-pass removal efficiency over multiple test procedures. These results indicate a high level of VOC removal efficiency for the active green wall biofilter tested and provide evidence that active biofiltration may aid in reducing exposure to VOCs in the indoor environment

    Advancing Social Determinants of Health Through Investments in Postsecondary Attainment and Sustaining Employment

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    In 2018, the Humana Foundation shifted the focus of its work to the social determinants of health, with the key aim of promoting health equity. With this new focus came a recognition that larger, long-term investments would be needed to support strategies addressing upstream determinants of health. The foundation also recognized the need to co-create processes with communities to understand how to provide essential holistic supports. This article explores one area of the foundation’s new efforts, the Strategic Community Investment Program, which focuses in part on postsecondary attainment and sustaining employment. The foundation partnered with the University of Louisville’s Center for Health Organization Transformation to systematically review models in the literature of successful postsecondary attainment strategies to evaluate the results in communities. This article shares key learnings from the literature and coordinated practice in communities that were used to revise the foundation’s strategy, and concludes with suggestions for other foundations interested in addressing postsecondary attainment and other social determinants of health to better meet the challenges and opportunities of the communities they serve

    From ‘greenest government ever’ to ‘get rid of all the green crap’: David Cameron, the Conservatives and the environment

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    The environment was David Cameron’s signature issue underpinning his modernization agenda. In opposition the ‘Vote Blue, Go Green’ strategy had a positive impact on the party’s image: the environment operated as a valence issue in a period of raised public concern, particularly about climate change, and Cameron’s high-profile support contributed to the cross-party consensus that delivered radical change in climate policy. Although the Coalition government has implemented important environmental measures, the Conservatives have not enhanced their green credentials in government and Cameron has failed to provide strong leadership on the issue. Since 2010, climate change has to some extent been transformed into a positional issue. Conservative MPs, urged on by the right-wing press, have adopted an increasingly partisan approach to climate change, and opinion polls reveal clear partisan divisions on climate change amongst public opinion. As a positional issue climate change has become challenging for the Conservatives, showing them to be internally divided, rebellious and inclined to support producer interests. This article makes a contribution to our understanding of Conservative modernization, while also challenging the dominant assumption in the scholarly literature that the environment, particularly climate change, is a valence issue

    Star formation in z>1 3CR host galaxies as seen by Herschel

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    We present Herschel (PACS and SPIRE) far-infrared (FIR) photometry of a complete sample of z>1 3CR sources, from the Herschel GT project The Herschel Legacy of distant radio-loud AGN (PI: Barthel). Combining these with existing Spitzer photometric data, we perform an infrared (IR) spectral energy distribution (SED) analysis of these landmark objects in extragalactic research to study the star formation in the hosts of some of the brightest active galactic nuclei (AGN) known at any epoch. Accounting for the contribution from an AGN-powered warm dust component to the IR SED, about 40% of our objects undergo episodes of prodigious, ULIRG-strength star formation, with rates of hundreds of solar masses per year, coeval with the growth of the central supermassive black hole. Median SEDs imply that the quasar and radio galaxy hosts have similar FIR properties, in agreement with the orientation-based unification for radio-loud AGN. The star-forming properties of the AGN hosts are similar to those of the general population of equally massive non-AGN galaxies at comparable redshifts, thus there is no strong evidence of universal quenching of star formation (negative feedback) within this sample. Massive galaxies at high redshift may be forming stars prodigiously, regardless of whether their supermassive black holes are accreting or not.Comment: 30 pages, 13 figures, 4 tables. Accepted for publication in A&
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