675 research outputs found

    Industry Evolution Through Consolidation: Implications for Addiction Treatment.

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    Drawing on experiences in other industries, this article argues that the business of addiction treatment is likely to be transformed by the advent of a period of consolidation, in which a number of small independent programs will be acquired by larger, better capitalized, and managerially more sophisticated enterprises. Consolidation will be driven by opportunities to leverage new technologies, to exploit new regulatory initiatives, and to introduce economies of scale and scope into an industry that is currently highly fragmented. The process is likely to result in segmentation of the market, with the coexistence of large, generalist, highly standardized firms and a number of small highly specialized firms. When an industry consolidates, the types and quality of services provided can improve through the adoption of best practices and through increased competition among larger providers. If these larger providers are publicly traded, however, efforts to improve will inevitably be influenced by pressures to maintain or increase quarter-to-quarter earnings and share prices, leaving open the long-term impact on service quality

    Probability distribution of density fluctuations in the non-linear regime

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    We present a general procedure for obtaining the present density fluctuation probability distribution given the statistics of the initial conditions. The main difficulties faced with regard to this problem are those related to the non-linear evolution of the density fluctuations and those posed by the fact that the fields we are interested in are the result of filtering an underlying field with structure down to scales much smaller than that of filtering. The solution to the latter problem is discussed here in detail and the solution to the former is taken from a previous work. We have checked the procedure for values of the rms density fluctuation as large as 3/2 and several power spectra and found that it leads to results in excellent agreement with those obtained in numerical simulations. We also recover all available exact results from perturbation theory.Comment: Accepted to be published in Ap

    A three-dimensional Galactic extinction model

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    A large-scale three-dimensional model of Galactic extinction is presented based on the Galactic dust distribution model of Drimmel and Spergel (2001). The extinction A_V to any point within the Galactic disk can be quickly deduced using a set of three-dimensional cartesian grids. Extinctions from the model are compared to empirical extinction measures, including lines-of-sight in and near the Galactic plane using optical and NIR extinction measures; in particular we show how extinction can be derived from NIR color-magnitude diagrams in the Galactic plane to a distance of 8 kiloparsec.Comment: 12 pages, to be published in A&

    A major star formation region in the receding tip of the stellar Galactic bar. II. Supplementary information and evidence that the bar is not the same structure as the triaxial bulge previouly reported

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    This paper is the second part of Garzon et al. (1997: ApJ 491, L31) in which we presented an outline of the analysis of 60 spectra from a follow-up program to the Two Micron Galactic Survey (TMGS) project in the l=27 deg., b=0 deg. area. In this second part, we present a more detailed explanation of the analysis as well a library of the spectra for more complete information for each of the 60 stars, and further discussions on the implications for the structure of the Galaxy. This region contains a prominent excess in the flux distribution and star counts previously observed in several spectral ranges, notably in the TMGS. More than 50% of the spectra of the stars detected with m_K<5.0 mag, within a very high confidence level, correspond to stars of luminosity class I, and a significant proportion of the remainder are very late giants which must also be rapidly evolving. We make the case, using all the available evidence, that we are observing a region at the nearer end of the Galactic bar, where the Scutum spiral arm breaks away, and that this is powerful evidence for the presence of the bar. Alternative explanations do not give nearly such a satisfactory account of the observations. The space localization of one and, a fortiori, of both ends of the bar allows us to infer a position angle for the bar of around 75 deg. with respect to the Sun-Galactic centre line. The angle is different from that given by other authors for the bar and this, we think, is because they refer to the triaxial bulge and not to the bar as detected here.Comment: 21 pages, 1 table, 9 figures, accepted in A

    First Report of CRISPR/Cas9 Gene Editing in Castanea sativa Mill

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    CRISPR/Cas9 has emerged as the most important tool for genome engineering due to its simplicity, design flexibility, and high efficiency. This technology makes it possible to induce point mutations in one or some target sequences simultaneously, as well as to introduce new genetic variants by homology-directed recombination. However, this approach remains largely unexplored in forest species. In this study, we reported the first example of CRISPR/Cas9-mediated gene editing in Castanea genus. As a proof of concept, we targeted the gene encoding phytoene desaturase (pds), whose mutation disrupts chlorophyll biosynthesis allowing for the visual assessment of knockout efficiency. Globular and early torpedo-stage somatic embryos of Castanea sativa (European chestnut) were cocultured for 5 days with a CRISPR/Cas9 construct targeting two conserved gene regions of pds and subsequently cultured on a selection medium with kanamycin. After 8 weeks of subculture on selection medium, four kanamycin-resistant embryogenetic lines were isolated. Genotyping of these lines through target Sanger sequencing of amplicons revealed successful gene editing. Cotyledonary somatic embryos were maturated on maltose 3% and cold-stored at 4°C for 2 months. Subsequently, embryos were subjected to the germination process to produce albino plants. This study opens the way to the use of the CRISPR/Cas9 system in European chestnut for biotechnological application

    Two-particle angular correlations in the search for new physics at future e+e−e^+e^- colliders

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    The analysis of angular particle correlations can yield valuable insights into the initial state of matter in high-energy collisions, thereby potentially revealing the existence of Beyond the Standard Model scenarios such as Hidden Valley (HV). In this study, we focus on a QCD-like hidden sector with relatively massive HV quarks (â‰Č100\lesssim 100~GeV) which might enlarge and strengthen azimuthal correlations of final-state SM hadrons. In particular, we study the formation and possible observation of \textit{ridge-like} structures in the angular two-particle correlation function at future e+e−e^+e^- colliders, with a much cleaner environment than in hadron colliders, such as the LHC.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

    Some doubts on the validity of the foreground Galactic contribution subtraction from microwave anisotropies

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    The Galactic foreground contamination in CMBR anisotropies, especially from the dust component, is not easily separable from the cosmological or extragalactic component. In this paper, some doubts will be raised concerning the validity of the methods used to date to remove Galactic dust emission in order to show that none of them achieves its goal. First, I review the recent bibliography on the topic and discuss critically the methods of foreground subtraction: the cross-correlation with templates, analysis assuming the spectral shape of the Galactic components, the "maximum entropy method", "internal linear combination", and "wavelet-based high resolution fitting of internal templates". Second, I analyse the galactic latitude dependence from WMAP data. The frequency dependence is discussed with the data in the available literature. The result is that all methods of subtracting the Galactic contamination are inaccurate. The galactic latitude dependence analysis or the frequency dependence of the anisotropies in the range 50-250 GHz put a constraint on the maximum Galactic contribution in the power spectrum to be less than a ~10% (68% C. L.) for a ~1 degree scale, and possibly higher for larger scales. The origin of most of the signal in the CMBR anisotropies is not Galactic. In any case, the subtraction of the Galaxy is not accurate enough to allow a "precision Cosmology"; other sources of contamination (extragalactic, solar system) are also present.Comment: 24 pages, 1 figure, accepted to be published in J. Astrophys. Ast

    Near-infrared and optical observations of galactic warps: A common, unexplained feature of most discs

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    Context: Warps occurring in galactic discs have been studied extensively in HI and in the optical, but rarely in the near-infrared (NIR) bands that trace the older stellar populations. Aims: We provide NIR data of nearby edge-on galaxies, combined with optical observations, for direct comparison of the properties of galactic warps as a function of wavelength, and calculate warp curves for each galaxy and obtain the characteristic warp parameters. We discuss these properties as possible constraints to the different mechanisms that have been proposed for the development and persistence of galactic warps. Methods: We observed 20 galaxies that were selected from a statistically complete diameter-limited subsample of edge-on disc galaxies. We used the Cerro Tololo Infrared Imager (CIRIM) at the CTIO 1.5m Ritchey-Chretien telescope to acquire the NIR data. We used the 1.54m Danish and 0.92m Dutch telescopes at the European Southern Observatory's La Silla site for our optical observations. Results: Our results show that 13 of our 20 sample galaxies are warped, with the warp more pronounced in the optical than at NIR wavelengths. In the remaining seven galaxies, no warp is apparent within the limitations of our automated detection method. The transition between the unperturbed inner disc and the outer, warped region is rather abrupt. S0 galaxies exhibit very small or no warps. The magnetic model remains one of a number of interesting formation scenarios.Comment: 16 page

    A major star formation region in the receding tip of the stellar Galactic bar

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    We present an analysis of the optical spectroscopy of 58 stars in the Galactic plane at l=27l=27\arcdeg, where a prominent excess in the flux distribution and star counts have been observed in several spectral regions, in particular in the Two Micron Galactic Survey (TMGS) catalog. The sources were selected from the TMGS, to have a KK magnitude brighter than +5 mag and be within 2 degrees of the Galactic plane. More than 60% of the spectra correspond to stars of luminosity class I, and a significant proportion of the remainder are very late giants which would also be fast evolving. This very high concentration of young sources points to the existence of a major star formation region in the Galactic plane, located just inside the assumed origin of the Scutum spiral arm. Such regions can form due to the concentrations of shocked gas where a galactic bar meets a spiral arm, as is observed at the ends of the bars of face-on external galaxies. Thus, the presence of a massive star formation region is very strong supporting evidence for the presence of a bar in our Galaxy.Comment: 13 pages (latex) + 4 figures (eps), accepted in ApJ Let

    The metallicity distributions in high-latitudes with SDSS

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    We present metallicities and their variations with different parameters for 36 high-latitude fields covering Galactic longitudes 0<l<360. The metallicities for relatively short vertical distances (z<2.5 kpc) show systematic fluctuations with Galactic longitude, similar to those of the thick-disc scaleheight, which may be interpreted as indicating a common origin, viz., the flare effect of the disc. This suggestion is supported by the metallicity variations which we find as functions of radial distance. The metallicity variation at larger vertical distances (6.5<z<9.5 kpc) is small but monotonic. Three different vertical metallicity gradients could be detected: d[M/H]/dz=-0.22(+/-0.03), d[M/H]/dz=-0.38 (+/-0.06), and d[M/H]/dz=-0.08 (+/-0.07) dex/kpc for the intervals z<3, 3<z<5, and 5<z<10 kpc, respectively. Since our data cover the whole Galactic longitude interval, the resulting metallicity gradients can be interpreted as properties of the larger-scale Galaxy. The first gradient confirms the dissipational formation of the disc at short z-distances. The steeper gradient corresponds to the transition region between different population components of the Galaxy, and finally, the lowest value provides an adequate description of the inner-halo metallicity gradient.Comment: 14 pages, 7 figures and 2 tables, accepted for publication in New Astronom
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