132 research outputs found

    Red Dragon: A Redshift-Evolving Gaussian Mixture Model for Galaxies

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    Precision-era optical cluster cosmology calls for a precise definition of the red sequence (RS), consistent across redshift. To this end, we present the Red Dragon algorithm: an error-corrected multivariate Gaussian mixture model (GMM). Simultaneous use of multiple colors and smooth evolution of GMM parameters result in a continuous RS and blue cloud (BC) characterization across redshift, avoiding the discontinuities of red fraction inherent in swapping RS selection colors. Based on a mid-redshift spectroscopic sample of SDSS galaxies, a RS defined by Red Dragon selects quenched galaxies (low specific star formation rate) with a balanced accuracy of over 90%. This approach to galaxy population assignment gives more natural separations between RS and BC galaxies than hard cuts in color--magnitude or color--color spaces. The Red Dragon algorithm is publicly available at bitbucket.org/wkblack/red-dragon-gamma.Comment: 17 pages, 14 figures; comments welcom

    How the other half lives: under the arch with Lady Henry Somerset

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    The reforming work of Isabella Caroline Somerset (Lady Henry Somerset 1851-1921) is largely overlooked today. Dedicated to women’s causes at home and abroad and to temperance in particular, having first-hand knowledge of the privileged and the underprivileged, this determined, multi-talented and opinionated woman uncharacteristically wrote a fictional novel, Under the Arch (1906). In the novel, London aristocrats are portrayed rubbing shoulders with slum dwellers, but there is little real connection. The problems that the social policies introduced by the Liberals from 1906-1914 would address are nevertheless highlighted. It can be no coincidence that Somerset was well acquainted with many of these politicians. The themes of relieving the poor, Christian doctrine, marriage, women’s suffrage and imperialism are addressed, although Somerset’s focus is simply on “doing good” and loving one’s neighbour.info:eu-repo/semantics/publishedVersio

    Exile Vol. XXIX No. 2

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    Photo by John Taylor 2 Poem by Ezra Pound 3 Photo by James Lundy 4 Balanced Budget by August West 5 The Lighter by John Zarchen 6-7 Photo by Theodore Granberg 8 Uptown by Christopher B. Brougham 9 Photo by Jeff Russell 9 Heartstrings by Pete Waters 10 Spell by Eric Stevenson 10 Mums by Mandy Wilson 10 A New Day by Chad Hussey 11 Photo by Chad Hussey 12 Solitare by Gordon Black 13-14 Photo by James Lundy 15 A Grave Day-Dream by John Zarchen 16 Photo by James Lundy 17 Photo by Pauela Theodotou 18 Reconciliation by R. T. Hayashi 19 Michigan Rt. 37 by Ruth Wick 20 Shenango Valley by August West 20 Photo by James Lundy 21 Drawing by Adrienne Wehr 22 Ultraviolet Blues by Kathy Shelton 23 New Orleans & The Silky Black Seams Of My Stockings by Kate Reynolds 23 Refraction by Pam Houston 23-31 Photo by James Lundy 32 A Midsummer Night\u27s... by R. T. Hayashi 33 Couch sleeping by Eric Stevenson 33 Before We Could Build by Kim Kiefer 34 Photo by Chad Hussey 35 The Legend Of The Bear Mother by Amy Pence 36 Photo by James Lundy 37 Cover Drawing by Peter Brooke -title pag

    Cosmological Simulations with Scale-Free Initial Conditions I: Adiabatic Hydrodynamics

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    We analyze hierarchical structure formation based on scale-free initial conditions in an Einstein-de Sitter universe, including a baryonic component. We present three independent, smoothed particle hydrodynamics (SPH) simulations, performed with two different SPH codes (TreeSPH and P3MSPH) at two resolutions. Each simulation is based upon identical initial conditions, which consist of Gaussian distributed initial density fluctuations that have an n=-1 power spectrum. The baryonic material is modeled as an ideal gas subject only to shock heating and adiabatic heating and cooling. The evolution is expected to be self-similar in time, and under certain restrictions we identify the expected scalings for many properties of the distribution of collapsed objects in all three realizations. The distributions of dark matter masses, baryon masses, and mass and emission weighted temperatures scale quite reliably. However, the density estimates in the central regions of these structures are determined by the degree of numerical resolution. As a result, mean gas densities and luminosities obey the expected scalings only when calculated within a limited dynamic range in density contrast. The temperatures and luminosities of the groups show tight correlations with the baryon masses, which can be well-represented by power-laws. The Press-Schechter (PS) approximation predicts the distribution of group dark matter and baryon masses fairly well, though it tends to overestimate the baryon masses. Combining the PS mass distribution with the measured relations for T(M) and L(M) predicts the temperature and luminosity distributions reasonably, though there are some discrepancies at high temperatures/luminosities. The three simulations agree well for the properties of groups that are resolved by 32 or more particles.Comment: 40 pages, 16 embedded postscript figures, uses AASTEX 4.0 style. Minor wording changes, to appear in ApJ. Abridged abstrac

    Approaches to reduce zinc and iron deficits in food systems

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    There is a deficit of mineral micronutrients in global food systems, known as ‘hidden hunger’, especially in the global south. This review focuses on zinc (Zn) and iron (Fe), whose entry into food systems depends primarily on soil and crop factors. Approaches to increase dietary supplies of Zn and Fe include: (1) supplementation, (2) food fortification, (3) dietary diversification, and (4) crop biofortification, including breeding and fertilizer-based approaches. Supply-based estimates indicate that Zn deficiency might be more widespread than Fe deficiency in sub-Saharan Africa, although there are major knowledge gaps at an individual biomarker level. Recent analytical advances, including the use of stable isotopes of Zn and Fe, can play an increasing role in improving our understanding of the movement of micronutrients in food systems, and thereby help to reduce the immense human cost of ‘hidden hunger’

    The role of fundamental solution in Potential and Regularity Theory for subelliptic PDE

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    In this survey we consider a general Hormander type operator, represented as a sum of squares of vector fields plus a drift and we outline the central role of the fundamental solution in developing Potential and Regularity Theory for solutions of related PDEs. After recalling the Gaussian behavior at infinity of the kernel, we show some mean value formulas on the level sets of the fundamental solution, which are the starting point to obtain a comprehensive parallel of the classical Potential Theory. Then we show that a precise knowledge of the fundamental solution leads to global regularity results, namely estimates at the boundary or on the whole space. Finally in the problem of regularity of non linear differential equations we need an ad hoc modification of the parametrix method, based on the properties of the fundamental solution of an approximating problem

    Evaluation of the impact of interdisciplinarity in cancer care

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    <p>Abstract</p> <p>Background</p> <p>Teamwork is a key component of the health care renewal strategy emphasized in Quebec, elsewhere in Canada and in other countries to enhance the quality of oncology services. While this innovation would appear beneficial in theory, empirical evidences of its impact are limited. Current efforts in Quebec to encourage the development of local interdisciplinary teams in all hospitals offer a unique opportunity to assess the anticipated benefits. These teams working in hospital outpatient clinics are responsible for treatment, follow-up and patient support. The study objective is to assess the impact of interdisciplinarity on cancer patients and health professionals.</p> <p>Methods/Design</p> <p>This is a quasi-experimental study with three comparison groups distinguished by intensity of interdisciplinarity: strong, moderate and weak. The study will use a random sample of 12 local teams in Quebec, stratified by intensity of interdisciplinarity. The instrument to measure the intensity of the interdisciplinarity, developed in collaboration with experts, encompasses five dimensions referring to aspects of team structure and process. Self-administered questionnaires will be used to measure the impact of interdisciplinarity on patients (health care utilization, continuity of care and cancer services responsiveness) and on professionals (professional well-being, assessment of teamwork and perception of teamwork climate). Approximately 100 health professionals working on the selected teams and 2000 patients will be recruited. Statistical analyses will include descriptive statistics and comparative analysis of the impact observed according to the strata of interdisciplinarity. Fixed and random multivariate statistical models (multilevel analyses) will also be used.</p> <p>Discussion</p> <p>This study will pinpoint to what extent interdisciplinarity is linked to quality of care and meets the complex and varied needs of cancer patients. It will ascertain to what extent interdisciplinary teamwork facilitated the work of professionals. Such findings are important given the growing prevalence of cancer and the importance of attracting and retaining health professionals to work with cancer patients.</p
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