2,312 research outputs found
A Test of the Lauer--Postman Bulk Flow
We use Tully--Fisher distances for a sample of field late spiral galaxies to
test the Lauer and Postman (1994; hereinafter LP) result suggestive of a bulk
flow with respect to the Cosmic Microwave Background reference frame, of
amplitude of +689 km/s in the direction l=343, b=+52. A total of 432 galaxies
are used, subdivided between two cones, of 30deg semiaperture each and pointed
respectively toward the apex and antapex of the LP motion. The peculiar
velocities in the two data sets are inconsistent with a bulk flow of the
amplitude claimed by LP. When combined in opposition, the peculiar velocity
medians in shells of constant redshift width are never larger than half the
amplitude of the LP bulk flow. Out to 5000 km/s the median bulk velocity in the
LP apex--antapex cones is about 200 km/s or less, dropping to a value
indistinguishable from zero beyond that distance. It can be excluded that field
spiral galaxies within 8000 km/s partake of a bulk flow of the amplitude and
direction reported by LP.Comment: 9 pages including figures embedded in text; uses AAS LaTex and psfi
The linked survival prospects of siblings : evidence for the Indian states
This paper reports an analysis of micro-data for India that shows a high correlation in infant mortality
among siblings. In 13 of 15 states, we identify a causal effect of infant death on the risk of infant death of the
subsequent sibling (a scarring effect), after controlling for mother-level heterogeneity. The scarring effects
are large, the only other covariate with a similarly large effect being motherâs (secondary or higher)
education. The two states in which evidence of scarring is weak are Punjab, the richest, and Kerala, the
socially most progressive. The size of the scarring effect depends upon the sex of the previous child in three
states, in a direction consistent with son-preference. Evidence of scarring implies that policies targeted at
reducing infant mortality will have social multiplier effects by helping avoid the death of subsequent
siblings. Comparison of other covariate effects across the states offers some interesting new insights
Survival and risk of adverse events in older patients receiving postoperative adjuvant chemotherapy for resected stages II-IIIA lung cancer: observational cohort study
Objective To compare the survival and risk of serious adverse events in older patients with stages II-IIIA non-small cell lung cancer treated with or without postoperative platinum based chemotherapy
Reinventing grounded theory: some questions about theory, ground and discovery
Grounded theoryâs popularity persists after three decades of broad-ranging critique. In this article three problematic notions are discussedââtheory,â âgroundâ and âdiscoveryââwhich linger in the continuing use and development of grounded theory procedures. It is argued that far from providing the epistemic security promised by grounded theory, these notionsâembodied in continuing reinventions of grounded theoryâconstrain and distort qualitative inquiry, and that what is contrived is not in fact theory in any meaningful sense, that âgroundâ is a misnomer when talking about interpretation and that what ultimately materializes following grounded theory procedures is less like discovery and more akin to invention. The procedures admittedly provide signposts for qualitative inquirers, but educational researchers should be wary, for the significance of interpretation, narrative and reflection can be undermined in the procedures of grounded theory
High-Redshift SDSS Quasars with Weak Emission Lines
We identify a sample of 74 high-redshift quasars (z>3) with weak emission
lines from the Fifth Data Release of the Sloan Digital Sky Survey and present
infrared, optical, and radio observations of a subsample of four objects at
z>4. These weak emission-line quasars (WLQs) constitute a prominent tail of the
Lya+NV equivalent width distribution, and we compare them to quasars with more
typical emission-line properties and to low-redshift active galactic nuclei
with weak/absent emission lines, namely BL Lac objects. We find that WLQs
exhibit hot (T~1000 K) thermal dust emission and have rest-frame 0.1-5 micron
spectral energy distributions that are quite similar to those of normal
quasars. The variability, polarization, and radio properties of WLQs are also
different from those of BL Lacs, making continuum boosting by a relativistic
jet an unlikely physical interpretation. The most probable scenario for WLQs
involves broad-line region properties that are physically distinct from those
of normal quasars.Comment: Updated to match version published in ApJ. 20 pages, 12 figure
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Cataclysmic Variables from Sloan Digital Sky Survey. VI. The Sixth Year (2005)
The 28 cataclysmic variables (CVs) found in 2005 in the Sloan Digital Sky Survey are presented with their coordinates, magnitudes, and spectra. Five of these systems are previously known CVs (HH Cnc, SX LMi, QZ Ser, AP CrB, and HS 1016+3412), and the rest are new discoveries. Additional spectroscopic, photometric, and/or polarimetric observations of 10 systems were carried out, resulting in estimates of the orbital periods for seven of the new binaries. The 23 new CVs include one eclipsing system, one new Polar, and five systems whose spectra clearly reveal atmospheric absorption lines from the underlying white dwarf
Barriers to primary care responsiveness to poverty as a risk factor for health
<p>Abstract</p> <p>Background</p> <p>Poverty is widely recognized as a major determinant of poor health, and this link has been extensively studied and verified. Despite the strong evidentiary link, little work has been done to determine what primary care health providers can do to address their patients' income as a risk to their health. This qualitative study explores the barriers to primary care responsiveness to poverty as a health issue in a well-resourced jurisdiction with near-universal health care insurance coverage.</p> <p>Methods</p> <p>One to one interviews were conducted with twelve experts on poverty and health in primary care in Ontario, Canada. Participants included family physicians, specialist physicians, nurse practitioners, community workers, advocates, policy experts and researchers. The interviews were analysed for anticipated and emergent themes.</p> <p>Results</p> <p>This study reveals provider- and patient-centred structural, attitudinal, and knowledge-based barriers to addressing poverty as a risk to health. While many of its findings reinforce previous work in this area, this study's findings point to a number of areas front line primary care providers could target to address their patients' poverty. These include a lack of provider understanding of the lived reality of poverty, leading to a failure to collect adequate data about patients' social circumstances, and to the development of inappropriate care plans. Participants also pointed to prejudicial attitudes among providers, a failure of primary care disciplines to incorporate approaches to poverty as a standard of care, and a lack of knowledge of concrete steps providers can take to address patients' poverty.</p> <p>Conclusions</p> <p>While this study reinforces, in a well-resourced jurisdiction such as Ontario, the previously reported existence of significant barriers to addressing income as a health issue within primary care, the findings point to the possibility of front line primary care providers taking direct steps to address the health risks posed by poverty. The consistent direction and replicability of these findings point to a refocusing of the research agenda toward an examination of interventions to decrease the health impacts of poverty.</p
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