1,383 research outputs found

    The Gaseous Extent of Galaxies and the Origin of \lya Absorption Systems. III. Hubble Space Telescope Imaging of \lya-Absorbing Galaxies at z < 1

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    We present initial results of a program to obtain and analyze HST WFPC2 images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We measure properties of 87 galaxies, of which 33 are associated with corresponding \lya absorption systems and 24 do not produce corresponding \lya absorption lines to within sensitive upper limits. Considering only galaxy and absorber pairs that are likely to be physically associated and excluding galaxy and absorber pairs within 3000 \kms of the background QSOs leaves 26 galaxy and absorber pairs and seven galaxies that do not produce corresponding \lya absorption lines to within sensitive upper limits. Redshifts of the galaxy and absorber pairs range from 0.0750 to 0.8912 with a median of 0.3718, and impact parameter separations of the galaxy and absorber pairs range from 12.4 to 157.4h1157.4 h^{-1} kpc with a median of 62.4h162.4 h^{-1} kpc. The primary result of the analysis is that the amount of gas encountered along the line of sight depends on the galaxy impact parameter and B-band luminosity but does not depend strongly on the galaxy average surface brightness, disk-to-bulge ratio, or redshift. This result confirms and improves upon the anti-correlation between \lya absorption equivalent width and galaxy impact parameter found previously by Lanzetta et al. (1995). There is no evidence that galaxy interactions play an important role in distributing tenuous gas around galaxies in most cases. Galaxies might account for all \lya absorption systems with W>0.3W > 0.3 \AA, but this depends on the unknown luminosity function and gaseous cross sections of low-luminosity galaxies as well as on the uncertainties of the observed number density of \lya absorption systems.Comment: Minor changes. Figure 1 stays intact and is available at ftp://ftp.ess.sunysb.edu/pub/lanzetta/wfpc

    A Tool-Supported Approach for Concurrent Execution of Heterogeneous Models

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    International audienceIn the software and systems modeling community, research on domain-specific modeling languages (DSMLs) is focused on providing technologies for developing languages and tools that allow domain experts to develop system solutions efficiently. Unfortunately, the current lack of support for explicitly relating concepts expressed in different DSMLs makes it very difficult for software and system engineers to reason about information spread across models describing different system aspects [4]. As a particular challenge, we investigate in this paper relationships between, possibly heterogeneous, behavioral models to support their concurrent execution. This is achieved by following a modular executable metamodeling approach for behavioral semantics understanding, reuse, variability and composability [5]. This approach supports an explicit model of concurrency (MoCC) [6] and domain-specific actions (DSA) [10] with a well-defined protocol between them (incl., mapping, feedback and callback) reified through explicit domain-specific events (DSE) [12]. The protocol is then used to infer a relevant behavioral language interface for specifying coordination patterns to be applied on conforming executable models [17]. All the tooling of the approach is gathered in the GEMOC studio, and outlined in the next section. Currently, the approach is experienced on a systems engineering language provided by Thales, named Capella 7. The goal and current state of the case study are exposed in this paper. 7 Cf. https://www.polarsys.org/capella

    Spectral Polarization of the Redshifted 21 cm Absorption Line Toward 3C 286

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    A re-analysis of the Stokes-parameter spectra obtained of the z=0.692 21 cm absorption line toward 3C 286 shows that our original claimed detection of Zeeman splitting by a line-of-sight magnetic field, B_los = 87 microgauss is incorrect. Because of an insidious software error, what we reported as Stokes V is actually Stokes U: the revised Stokes V spectrum indicates a 3-sigma upper limit of B_los < 17 microgauss. The correct analysis reveals an absorption feature in fractional polarization that is offset in velocity from the Stokes I spectrum by -1.9 km/s. The polarization position-angle spectrum shows a dip that is also significantly offset from the Stokes I feature, but at a velocity that differs slightly from the absorption feature in fractional polarization. We model the absorption feature with 3 velocity components against the core-jet structure of 3C 286. Our chisquare minimization fitting results in components with differing (1) ratios of H I column density to spin temperature, (2) velocity centroids, and (3) velocity dispersions. The change in polarization position angle with frequency implies incomplete coverage of the background jet source by the absorber. It also implies a spatial variation of the polarization position angle across the jet source, which is observed at frequencies higher than the 839.4 MHz absorption frequency. The multi-component structure of the gas is best understood in terms of components with spatial scales of ~100 pc comprised of hundreds of low-temperature (T < 200 K) clouds with linear dimensions of about 1 pc.Comment: Accepted for Publication by the Astrophysical Journa

    Arc Deformation and Marginal Basin Opening: Japan Sea as a Case Study

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    Laurent Jolivet est est Professeur à l'Université d'Orléans depuis le 1er Septembre 2009International audienceWe discuss the opening mechanism of the Japan Sea in Miocene time using (1) tectonic and published paleomagnetic data along the eastern margin from the north of Hokkaido Island to Sado Island, (2) a mechanical model which is tested by small-scale physical modeling, and (3) crustal structure and bathymetric features in the Japan Sea which constrain our kinematic model and preopening reconstructions. Our main conclusions are the following. The eastern margin of the Japan Sea was, as a whole, a dextral shear zone about 100 km wide. This conclusion is supported by the existence of a ductile dextral shear zone in Central Hokkaido (Hidaka Mountains) and associated brittle deformation in western Hokkaido and northeastern Honshu. The stress field during the opening (which ended about 12 Ma ago at the end of the middle Miocene) changes from right-lateral transpression in the north to right-lateral transtension in the south. The western margin, along the Korean peninsula, during the same period, also was an active dextral shear zone. Paleomagnetic results indicate that clockwise rotations occurred in the south during the opening and counterclockwise rotations in the north. We propose a model of right-lateral pull-apart deformation with clockwise rotations of rigid blocks in the southern transtensional domain and counterclockwise rotations in the transpressional one. Small-scale physical models show that the clockwise rotation in transtension is possible provided that the eastern boundary (Pacific side) is free of stress. The opening stopped and compression subsequently began about 12 Ma ago. Finally, we show that the dextral shear, which is distributed over the whole Japan Sea area, is accommodated by N-S trending right-lateral faults and rotation of blocks located between these right-lateral faults

    Lyman-alpha Forest Tomography from Background Galaxies: The First Megaparsec-Resolution Large-Scale Structure Map at z>2

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    We present the first observations of foreground Lyman-α\alpha forest absorption from high-redshift galaxies, targeting 24 star-forming galaxies (SFGs) with z2.32.8z\sim 2.3-2.8 within a 5×155' \times 15' region of the COSMOS field. The transverse sightline separation is 2h1Mpc\sim 2\,h^{-1}\mathrm{Mpc} comoving, allowing us to create a tomographic reconstruction of the 3D Lyα\alpha forest absorption field over the redshift range 2.20z2.452.20\leq z\leq 2.45. The resulting map covers 6h1Mpc×14h1Mpc6\,h^{-1}\mathrm{Mpc} \times 14\,h^{-1}\mathrm{Mpc} in the transverse plane and 230h1Mpc230\,h^{-1}\mathrm{Mpc} along the line-of-sight with a spatial resolution of 3.5h1Mpc\approx 3.5\,h^{-1}\mathrm{Mpc}, and is the first high-fidelity map of large-scale structure on Mpc\sim\mathrm{Mpc} scales at z>2z>2. Our map reveals significant structures with 10h1Mpc\gtrsim 10\,h^{-1}\mathrm{Mpc} extent, including several spanning the entire transverse breadth, providing qualitative evidence for the filamentary structures predicted to exist in the high-redshift cosmic web. Simulated reconstructions with the same sightline sampling, spectral resolution, and signal-to-noise ratio recover the salient structures present in the underlying 3D absorption fields. Using data from other surveys, we identified 18 galaxies with known redshifts coeval with our map volume enabling a direct comparison to our tomographic map. This shows that galaxies preferentially occupy high-density regions, in qualitative agreement with the same comparison applied to simulations. Our results establishes the feasibility of the CLAMATO survey, which aims to obtain Lyα\alpha forest spectra for 1000\sim 1000 SFGs over 1deg2\sim 1 \,\mathrm{deg}^2 of the COSMOS field, in order to map out IGM large-scale structure at z2.3\langle z \rangle \sim 2.3 over a large volume (100h1Mpc)3(100\,h^{-1}\mathrm{Mpc})^3.Comment: Accepted for publication in Astrophysical Journal Letters; 8 pages and 5 figure

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Search for stop and higgsino production using diphoton Higgs boson decays

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    Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass
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