132 research outputs found
Red Dragon: A Redshift-Evolving Gaussian Mixture Model for Galaxies
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
The reforming work of Isabella Caroline Somerset (Lady Henry Somerset 1851-1921) is largely overlooked today. Dedicated to womenâs 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, womenâs suffrage and imperialism are addressed, although Somersetâs focus is simply on âdoing goodâ and loving oneâs neighbour.info:eu-repo/semantics/publishedVersio
Exile Vol. XXIX No. 2
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
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
Recommended from our members
An Online Database for Informing Ecological Network Models: http://kelpforest.ucsc.edu
Ecological network models and analyses are recognized as valuable tools for understanding the dynamics and resiliency of
ecosystems, and for informing ecosystem-based approaches to management. However, few databases exist that can
provide the life history, demographic and species interaction information necessary to parameterize ecological network
models. Faced with the difficulty of synthesizing the information required to construct models for kelp forest ecosystems
along the West Coast of North America, we developed an online database (http://kelpforest.ucsc.edu/) to facilitate the
collation and dissemination of such information. Many of the databaseâs attributes are novel yet the structure is applicable
and adaptable to other ecosystem modeling efforts. Information for each taxonomic unit includes stage-specific life history,
demography, and body-size allometries. Species interactions include trophic, competitive, facilitative, and parasitic forms.
Each data entry is temporally and spatially explicit. The online data entry interface allows researchers anywhere to
contribute and access information. Quality control is facilitated by attributing each entry to unique contributor identities
and source citations. The database has proven useful as an archive of species and ecosystem-specific information in the
development of several ecological network models, for informing management actions, and for education purposes (e.g.,
undergraduate and graduate training). To facilitate adaptation of the database by other researches for other ecosystems,
the code and technical details on how to customize this database and apply it to other ecosystems are freely available and
located at the following link (https://github.com/kelpforest-cameo/databaseui)
Approaches to reduce zinc and iron deficits in food systems
There is a deficit of mineral micronutrients in global food systems, known as âhidden hungerâ, 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 âhidden hungerâ
The role of fundamental solution in Potential and Regularity Theory for subelliptic PDE
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
<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
The Dynamics of Protest Diffusion: Movement Organizations, Social Networks, and News Media in the 1960 Sit-Ins
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