569 research outputs found
The Angular Two-Point Correlation Function for the FIRST Radio Survey
The FIRST (Faint Images of the Radio Sky at Twenty Centimeters) survey now
covers 1550 square degrees of sky where and
. This yields a catalog of 138,665 sources
above the survey threshold of 1 mJy, about one third of which are in
double-lobed and multi-component sources. We have used these data to obtain the
first high-significance measurement of the two-point angular correlation for a
deep radio sample. We find that the correlation function between
and is well fitted by a power law of the form
where and . On small scales
(), double and multi-component sources are shown to have a
larger clustering amplitude than that of the whole sample. Sources with flux
densities below 2 mJy are found to have a shallower slope than that obtained
for the whole sample, consistent with there being a significant contribution
from starbursting galaxies at these faint fluxes. The cross-correlation of
radio sources and Abell clusters is determined. A preliminary approach to
inferring spatial information is outlined.Comment: 22 pages, latex, 4 figures. To appear in Astrophysical Journal.
Replaced paper contains a revised value for the the spatial correlation
function amplitude (r_0
Demographic and Clinical Characteristics of Mucinous Epithelial Ovarian Cancer, and Survival Following a Mucinous Epithelial Ovarian Cancer Diagnosis
Alternative & renewable energy sources & technolog
Correlation between structure and electrical transport in ion-irradiated graphene grown on Cu foils
Graphene grown by chemical vapor deposition and supported on SiO2 and
sapphire substrates was studied following controlled introduction of defects
induced by 35 keV carbon ion irradiation. Changes in Raman spectra following
fluences ranging from 10^12 cm^-2 to 10^15 cm^-2 indicate that the structure of
graphene evolves from a highly ordered layer, to a patchwork of disordered
domains, to an essentially amorphous film. These structural changes result in a
dramatic decrease in the Hall mobility by orders of magnitude while,
remarkably, the Hall concentration remains almost unchanged, suggesting that
the Fermi level is pinned at a hole concentration near 1x10^13 cm^-2. A model
for scattering by resonant scatterers is in good agreement with mobility
measurements up to an ion fluence of 1x10^14 cm^-2
Factors associated with initial treatment and survival for clinically localized prostate cancer: results from the CDC-NPCR Patterns of Care Study (PoC1)
<p>Abstract</p> <p>Background</p> <p>Despite the large number of men diagnosed with localized prostate cancer, there is as yet no consensus concerning appropriate treatment. The purpose of this study was to describe the initial treatment patterns for localized prostate cancer in a population-based sample and to determine the clinical and patient characteristics associated with initial treatment and overall survival.</p> <p>Methods</p> <p>The analysis included 3,300 patients from seven states, diagnosed with clinically localized prostate cancer in 1997. We examined the association of sociodemographic and clinical characteristics with four treatment options: radical prostatectomy, radiation therapy, hormone therapy, and watchful waiting. Diagnostic and treatment information was abstracted from medical records. Socioeconomic measures were derived from the 2000 Census based on the patient's residence at time of diagnosis. Vital status through December 31, 2002, was obtained from medical records and linkages to state vital statistics files and the National Death Index. Multiple logistic regression analysis and Cox proportional hazards models identified factors associated with initial treatment and overall survival, respectively.</p> <p>Results</p> <p>Patients with clinically localized prostate cancer received the following treatments: radical prostatectomy (39.7%), radiation therapy (31.4%), hormone therapy (10.3%), or watchful waiting (18.6%). After multivariable adjustment, the following variables were associated with conservative treatment (hormone therapy or watchful waiting): older age, black race, being unmarried, having public insurance, having non-screen detected cancer, having normal digital rectal exam results, PSA values above 20, low Gleason score (2-4), comorbidity, and state of residence. Among patients receiving definitive treatment (radical prostatectomy or radiation therapy), older age, being unmarried, PSA values above 10, unknown Gleason score, state of residence, as well as black race in patients under 60 years of age, were associated with receipt of radiation therapy. Overall survival was related to younger age, being married, Gleason score under 8, radical prostatectomy, and state of residence. Comorbidity was only associated with risk of death within the first three years of diagnosis.</p> <p>Conclusions</p> <p>In the absence of clear-cut evidence favoring one treatment modality over another, it is important to understand the factors that inform treatment selection. Since state of residence was a significant predictor of both treatment as well as overall survival, true regional differences probably exist in how physicians and patients select treatment options. Factors affecting treatment choice and treatment effectiveness need to be further explored in future population-based studies.</p
Digital image analysis using video microscopy of human-derived prostate cancer vs normal prostate organoids to assess migratory behavior on extracellular matrix proteins
The advent of perpetuating living organoids derived from patient tissue is a promising avenue for cancer research but is limited by difficulties with precise characterization. In this brief communication, we demonstrate via time-lapse imaging distinct phenotypes of prostate organoids derived from patient material– without confirmation of cellular identity. We show that organoids derived from histologically normal tissue more readily spread on a physiologic extracellular matrix (ECM) than on pathologic ECM (p<0.0001), while tumor-derived organoids spread equally on either substrate (p=0.2406). This study is an important proof-of-concept to defer precise characterization of organoids and still glean information into disease pathology
New Constraint on Open Cold-Dark-Matter Models
We calculate the large-angle cross-correlation between the
cosmic-microwave-background (CMB) temperature and the x-ray-background (XRB)
intensity expected in an open Universe with cold dark matter (CDM) and a nearly
scale-invariant spectrum of adiabatic density perturbations. Results are
presented as a function of the nonrelativistic-matter density (in
units of the critical density) and the x-ray bias (evaluated at a
redshift in evolving-bias models) for both an open Universe and a
flat cosmological-constant Universe. Recent experimental upper limits to the
amplitude of this cross-correlation provide a new constraint to the
- parameter space that open-CDM models (and the open-inflation
models that produce them) must satisfy.Comment: 4 pages, LaTeX. Revised version contains additional figure that
clarifies new constraint. (To appear in PRL.
Constraints on the Clustering, Biasing and Redshift Distribution of Radio Sources
We discuss how different theoretical predictions for the variance
of the distribution of radio sources can be matched to measurements from the
FIRST survey at different flux limits. The predictions are given by the
integration of models for the angular correlation function for
three different functional forms of the redshift distribution , different
spatial correlation functions and by different evolutions of the bias
with redshift. We also consider the two cases of open and flat Universes.
Although the predicted show substantial differences due to
differences in the 's, these differences are not significant compared to
the uncertainties in the current observations. It turns out that the best fit
is provided by models with constant biasing at all times, although the
difference between models with epoch-independent bias and models with bias that
evolves linearly with redshift is not very large. All models with strong
evolution of bias with epoch are ruled out. As a further step we directly
calculated at 3mJy from the catalogue and matched it with our
models for the angular correlation function in the hypothesis that the
clustering signal comes from two different populations, namely AGN-powered
sources and starbursting galaxies. The results are consistent with a scenario
for hierarchical clustering where the fainter starbursting galaxies trace the
mass at all epochs, while brighter AGN's are strongly biased, with
evolving linearly with redshift, as suggested by some theories of galaxy
formation and evolution.Comment: 14 pages, 12 figures, version to appear on MNRA
Characterization of particulate size distributions and water-soluble ions measured at a broiler farm
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