95 research outputs found
Sunyaev-Zeldovich effect in WMAP and its effect on cosmological parameters
We use multi-frequency information in first year WMAP data to search for the
Sunyaev-Zeldovich (SZ) effect. WMAP has sufficiently broad frequency coverage
to constrain SZ without the addition of higher frequency data: the SZ power
spectrum amplitude is expected to increase 50% from W to Q frequency band.
This, in combination with the low noise in WMAP, allows us to strongly
constrain the SZ contribution. We derive an optimal frequency combination of
WMAP cross-spectra to extract SZ in the presence of noise, CMB, and radio point
sources, which are marginalized over. We find that the SZ contribution is less
than 2% (95% c.l.) at the first acoustic peak in W band. Under the assumption
that the removed radio point sources are not correlated with SZ this limit
implies sigma_8<1.07 at 95% c.l. We investigate the effect on the cosmological
parameters of allowing an SZ component. We run Monte Carlo Markov Chains with
and without an SZ component and find that the addition of SZ does not affect
any of the cosmological conclusions. We conclude that SZ does not contaminate
the WMAP CMB or change cosmological parameters, refuting the recent claims that
they may be corrupted.Comment: 10 pages, 5 figures, 2 tables. Submitted to Phys. Rev.
Cyber risk at the edge: Current and future trends on cyber risk analytics and artificial intelligence in the industrial internet of things and industry 4.0 supply chains
Digital technologies have changed the way supply chain operations are structured. In this article, we conduct systematic syntheses of literature on the impact of new technologies on supply chains and the related cyber risks. A taxonomic/cladistic approach is used for the evaluations of progress in the area of supply chain integration in the Industrial Internet of Things and Industry 4.0, with a specific focus on the mitigation of cyber risks. An analytical framework is presented, based on a critical assessment with respect to issues related to new types of cyber risk and the integration of supply chains with new technologies. This paper identifies a dynamic and self-adapting supply chain system supported with Artificial Intelligence and Machine Learning (AI/ML) and real-time intelligence for predictive cyber risk analytics. The system is integrated into a cognition engine that enables predictive cyber risk analytics with real-time intelligence from IoT networks at the edge. This enhances capacities and assist in the creation of a comprehensive understanding of the opportunities and threats that arise when edge computing nodes are deployed, and when AI/ML technologies are migrated to the periphery of IoT networks
Mathematical Morphology: Star/Galaxy Differentiation & Galaxy Morphology Classification
We present an application of Mathematical Morphology (MM) for the
classification of astronomical objects, both for star/galaxy differentiation
and galaxy morphology classification. We demonstrate that, for CCD images, 99.3
+/- 3.8 % of galaxies can be separated from stars using MM, with 19.4 +/- 7.9 %
of the stars being misclassified. We demonstrate that, for photographic plate
images, the number of galaxies correctly separated from the stars can be
increased using our MM diffraction spike tool, which allows 51.0 +/- 6.0 % of
the high-brightness galaxies that are inseparable in current techniques to be
correctly classified, with only 1.4 +/- 0.5 % of the high-brightness stars
contaminating the population. We demonstrate that elliptical (E) and late-type
spiral (Sc-Sd) galaxies can be classified using MM at an accuracy of 91.4 +/-
7.8 %. It is a method involving less `free parameters' than current techniques,
especially automated machine learning algorithms. The limitation of MM galaxy
morphology based on seeing and distance is also presented. We examine various
star/galaxy differentiation and galaxy morhpology classification techniques
commonly used today, and show that the above MM techniques compare very
favourably.Comment: 13 pages, 11 figures, accepted for publication in PAS
Using a complete spectroscopic survey to find red quasars and test the KX method
We present an investigation of quasar colour-redshift parameter space in
order to search for radio-quiet red quasars and to test the ability of a
variant of the KX quasar selection method to detect quasars over a full range
of colour without bias. This is achieved by combining IRIS2 imaging with the
complete Fornax Cluster Spectroscopic Survey to probe parameter space
unavailable to other surveys. We construct a new sample of 69 quasars with
measured bJ - K colours. We show that the colour distribution of these quasars
is significantly different from that of the Large Bright Quasar Survey's
quasars at a 99.9% confidence level. We find 11 of our sample of 69 quasars
have signifcantly red colours (bJ - K >= 3.5) and from this, we estimate the
red quasar fraction of the K <= 18.4 quasar population to be 31%, and robustly
constrain it to be at least 22%. We show that the KX method variant used here
is more effective than the UVX selection method, and has less colour bias than
optical colour-colour selection methods.Comment: 11 pages, 14 figures, accepted for publication in MNRA
A New Algorithm for the Detection of Inter-cluster Galaxy Filaments using Galaxy Orientation Alignments
We present a new algorithm to detect inter-cluster galaxy filaments based
upon the assumption that the orientations of constituent galaxies along such
filaments are non-isotropic. We apply the algorithm to the 2dF Galaxy Redshift
Survey catalogue and find that it readily detects many straight filaments
between close cluster pairs. At large inter-cluster separations (>15 Mpc), we
find that the detection efficiency falls quickly, as it also does with more
complex filament morphologies. We explore the underlying assumptions and
suggest that it is only in the case of close cluster pairs that we can expect
galaxy orientations to be significantly correlated with filament direction.Comment: 7 pages, 5 figures, accepted for publication in MNRA
Oral Anticoagulant Therapy Prescription in Patients With Atrial Fibrillation Across the Spectrum of Stroke Risk: Insights From the NCDR PINNACLE Registry
IMPORTANCE: Patients with atrial fibrillation (AF) are at a proportionally higher risk of stroke based on accumulation of well-defined risk factors.
OBJECTIVE: To examine the extent to which prescription of an oral anticoagulant (OAC) in US cardiology practices increases as the number of stroke risk factors increases.
DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional registry study of outpatients with AF enrolled in the American College of Cardiology National Cardiovascular Data Registry's PINNACLE (Practice Innovation and Clinical Excellence) Registry between January 1, 2008, and December 30, 2012. As a measure of stroke risk, we calculated the CHADS2 score and the CHA2DS2-VASc score for all patients. Using multinomial logistic regression models adjusted for patient, physician, and practice characteristics, we examined the association between increased stroke risk score and prescription of an OAC.
MAIN OUTCOMES AND MEASURES: The primary outcome was prescription of an OAC with warfarin sodium or a non-vitamin K antagonist OAC.
RESULTS: The study cohort comprised 429 417 outpatients with AF. Their mean (SD) age was 71.3 (12.9) years, and 55.8% were male. Prescribed treatment consisted of an OAC (192 600 [44.9%]), aspirin only (111 134 [25.9%]), aspirin plus a thienopyridine (23 454 [5.5%]), or no antithrombotic therapy (102 229 [23.8%]). Each 1-point increase in risk score was associated with increased odds of OAC prescription compared with aspirin-only prescription using the CHADS2 score (adjusted odds ratio, 1.158; 95% CI, 1.144-1.172; P < .001) and the CHA2DS2-VASc score (adjusted odds ratio, 1.163; 95% CI, 1.157-1.169; P < .001). Overall, OAC prescription prevalence did not exceed 50% even in higher-risk patients with a CHADS2 score exceeding 3 or a CHA2DS2-VASc score exceeding 4.
CONCLUSIONS AND RELEVANCE: In a large quality improvement registry of outpatients with AF, prescription of OAC therapy increased with a higher CHADS2 score and CHA2DS2-VASc score. However, a plateau of OAC prescription was observed, with less than half of high-risk patients receiving an OAC prescription
Combo Night 2011
UNF Music Flagship Program Presents Combo Night Featuring UNF Jazz Studies Students
Wednesday, October 5, 2011 UNF Fine Arts Center - Choir Room, 140
The architecture of Abell 1386 and its relationship to the Sloan Great Wall
We present new radial velocities from AAOmega on the Anglo-Australian
Telescope for 307 galaxies (b_J < 19.5) in the region of the rich cluster Abell
1386. Consistent with other studies of galaxy clusters that constitute
sub-units of superstructures, we find that the velocity distribution of A1386
is very broad (21,000--42,000 kms^-1, or z=0.08--0.14) and complex. The mean
redshift of the cluster that Abell designated as number 1386 is found to be
~0.104. However, we find that it consists of various superpositions of
line-of-sight components. We investigate the reality of each component by
testing for substructure and searching for giant elliptical galaxies in each
and show that A1386 is made up of at least four significant clusters or groups
along the line of sight whose global parameters we detail. Peculiar velocities
of brightest galaxies for each of the groups are computed and found to be
different from previous works, largely due to the complexity of the sky area
and the depth of analysis performed in the present work. We also analyse A1386
in the context of its parent superclusters: Leo A, and especially the Sloan
Great Wall. Although the new clusters may be moving toward mass concentrations
in the Sloan Great Wall or beyond, many are most likely not yet physically
bound to it.Comment: 21 pages, 9 figures, includes the full appendix table. Accepted for
publication in MNRA
CHILES: HI morphology and galaxy environment at z=0.12 and z=0.17
We present a study of 16 HI-detected galaxies found in 178 hours of
observations from Epoch 1 of the COSMOS HI Large Extragalactic Survey (CHILES).
We focus on two redshift ranges between 0.108 <= z <= 0.127 and 0.162 <= z <=
0.183 which are among the worst affected by radio frequency interference (RFI).
While this represents only 10% of the total frequency coverage and 18% of the
total expected time on source compared to what will be the full CHILES survey,
we demonstrate that our data reduction pipeline recovers high quality data even
in regions severely impacted by RFI. We report on our in-depth testing of an
automated spectral line source finder to produce HI total intensity maps which
we present side-by-side with significance maps to evaluate the reliability of
the morphology recovered by the source finder. We recommend that this become a
common place manner of presenting data from upcoming HI surveys of resolved
objects. We use the COSMOS 20k group catalogue, and we extract filamentary
structure using the topological DisPerSE algorithm to evaluate the \hi\
morphology in the context of both local and large-scale environments and we
discuss the shortcomings of both methods. Many of the detections show disturbed
HI morphologies suggesting they have undergone a recent interaction which is
not evident from deep optical imaging alone. Overall, the sample showcases the
broad range of ways in which galaxies interact with their environment. This is
a first look at the population of galaxies and their local and large-scale
environments observed in HI by CHILES at redshifts beyond the z=0.1 Universe.Comment: 23 pages, 12 figures, 1 interactive 3D figure, accepted to MNRA
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