21 research outputs found
The Ku-band Polarization Identifier
The Ku-band Polarization Identifier (KUPID) will integrate a very low noise
12-18 GHz, correlation polarimeter onto the Crawford Hill seven meter,
millimeter-wave antenna. The primary components of the polarimeter will be
built at the University of Miami and other key components, including the
microwave horn and data acquisition system will be built at the University of
Chicago and Princeton University. This project will measure the Q and U Stokes
parameters in regions near the north celestial pole, in regions of low galactic
contamination, and in regions near the galactic plane. The KUPID survey
experiment makes use of many of the techniques employed in the Princeton IQU
Experiment (PIQUE) that was developed by the members of this collaboration to
detect CMB polarization at shorter wavelengths. The KUPID experiment will be
constructed in parallel and on the same timescale as the CAPMAP experiment (see
Barkats, this volume) which is the follow-on experiment to PIQUE. KUPID will
observe on the Crawford Hill antenna from late spring until early autumn, while
CAPMAP will observe during the lower water vapor months of late autumn until
early spring.Comment: To be published in the proceedings of "The Cosmic Microwave
Background and its Polarization", New Astronomy Reviews, (eds. S. Hanany and
K. A. Olive
Cosmic Microwave Background Anisotropies from Scaling Seeds: Global Defect Models
We investigate the global texture model of structure formation in cosmogonies
with non-zero cosmological constant for different values of the Hubble
parameter. We find that the absence of significant acoustic peaks and little
power on large scales are robust predictions of these models. However, from a
careful comparison with data we conclude that at present we cannot safely
reject the model on the grounds of present CMB data. Exclusion by means of
galaxy correlation data requires assumptions on biasing and statistics. New,
very stringent constraints come from peculiar velocities.
Investigating the large-N limit, we argue that our main conclusions apply to
all global O(N) models of structure formation.Comment: LaTeX file with RevTex, 27 pages, 23 eps figs., submitted to Phys.
Rev. D. A version with higher quality images can be found at
http://mykonos.unige.ch/~kunz/download/lam.tar.gz for the LaTeX archive and
at http://mykonos.unige.ch/~kunz/download/lam.ps.gz for the compiled
PostScript fil
Hypersurface-Invariant Approach to Cosmological Perturbations
Using Hamilton-Jacobi theory, we develop a formalism for solving
semi-classical cosmological perturbations which does not require an explicit
choice of time-hypersurface. The Hamilton-Jacobi equation for gravity
interacting with matter (either a scalar or dust field) is solved by making an
Ansatz which includes all terms quadratic in the spatial curvature.
Gravitational radiation and scalar perturbations are treated on an equal
footing. Our technique encompasses linear perturbation theory and it also
describes some mild nonlinear effects. As a concrete example of the method, we
compute the galaxy-galaxy correlation function as well as large-angle microwave
background fluctuations for power-law inflation, and we compare with recent
observations.Comment: 51 pages, Latex 2.09 ALBERTA THY/20-94, DAMTP R94/25 To appear in
Phys. Rev.
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The Ku-band polarization identifier
The Ku-band polarization identifier (KUPID) will integrate a very low noise 12–18 GHz, correlation polarimeter onto the Crawford Hill seven meter, millimeter-wave antenna. The primary components of the polarimeter will be built at the University of Miami and other key components, including the microwave horn and data acquisition system will be built at the University of Chicago and Princeton University. This project will measure the
Q and
U Stokes parameters in regions near the north celestial pole, in regions of low galactic contamination, and in regions near the galactic plane. The KUPID survey experiment makes use of many of the techniques employed in the Princeton IQU experiment (PIQUE) that was developed by the members of this collaboration to detect CMB polarization at shorter wavelengths. The KUPID experiment will be constructed in parallel and on the same timescale as the CAPMAP experiment (see Barkats, this volume) which is the follow-on experiment to PIQUE. KUPID will observe on the Crawford Hill antenna from late spring until early autumn, while CAPMAP will observe during the lower water vapor months of late autumn until early spring
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Iridium thin films deposited via pulsed laser deposition for future applications as transition-edge sensors
The University of Miami has recently started developing and studying high-resolution microcalorimeters operating near 100mK for X-ray and particle physics and astrophysics. These detectors will be based on Transition Edge Sensors technology fabricated using iridium thin films deposited via the Pulsed Laser Deposition technique. We report here the preliminary result of the room temperature characterization of the Ir thin films, and an overview of future plans to use the films as transition edge sensors
The distribution of small preantral follicles within the ovaries of prepubertal African elephants (Loxodonta africana)
BACKGROUND: Data on the distribution of primordial (single layer of squamous granulosa cells), early primary (some granulosa cells cuboidal) and primary (all granulosa cells cuboidal) follicles, grouped together as small follicles (SF) within the ovary of the elephant is lacking, yet such information is necessary to be able to estimate accurately the total numbers of small follicles in the ovaries of elephant throughout their lifespan.
AIM: To determine if the density of SF differs between ovaries, between the surfaces of an ovary, or between the interpolar and intermarginal zones of an ovary.
MATERIALS/METHODS: Stereological techniques were employed on 25 ÎĽm thick histological sections of the ovaries recovered from 12 prepubertal elephant calves aged 2 months to 4.5 years. Cell densities were calculated using the optical brick method and Cavalieri's principle for volume calculation.
RESULTS: The density of SF (numbers of SF per unbiased counting frame [UCF]) did not differ between the left (1.11 ± 0.39 (mean ± sd)) and right (1.10 ± 0.39) ovaries (P = 0.82, n = 12), or between the lateral (median 1.24; interquartile range 0.85–1.39) and medial (1.03; 0.76–1.36) surfaces of the ovary (P = 0.22, n = 24) or among the 5 segments of the ovary between the two poles (P = 0.20, n = 24). The third of the cortex nearest to the mesovarial margin of the ovary had fewer small follicles per UCF (0.85; 0.51–1.28) than the middle third (1.01; 0.78–1.42; P = 0.034), and the third adjacent to the free margin (1.27; 0.79–1.51; P = 0.0024), n = 24 per group.
CONCLUSION: Providing a random sample is taken from the full interpolar and intermarginal dimensions of ovary of a non-pregnant elephant, the density of small follicles throughout the cortex may be accurately measured using stereological techniques applied to one of its surfaces.http://www.elsevier.com/locate/anireprosciab201
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Measurements of anisotropy in the cosmic microwave backgroundradiation at 0 degrees.5 scales near the stars HR 5127 and phiHerculis
We present measurements of cosmic microwave background (CMB) anisotropy near the stars HR 5127 and phi Herculis from the fifth flight of the Millimeter-wave Anisotropy eXperiment (MAX). We scanned 8 degrees strips of the sky with an approximately Gaussian 0.5 degrees FWHM beam and a 1.4 degrees peak to peak sinusoidal chop. The instrument has four frequency bands centered at 3.5, 6, 9, and 14 cm(-1). The IRAS 100 mu mmap predicts that these two regions have low interstellar dust contrast. The HR 5127 data are consistent with CMB anisotropy. The phi Herculis data, which were measured at lower flight altitudes, show time variability at 9 and 14 cm(-1), which we believe to be due to atmospheric emission. However, the phi Herculis data at 3.5 and 6 cm-l are essentially independent of this atmospheric contribution and are consistent with CMB anisotropy. Confusion from Galactic foregrounds is unlikely based on the spectrum and amplitude of the structure at these frequencies. If the observed HR 5127 structure and the atmosphere-independent phi Herculis structure are attributed to CMB anisotropy, then we find Delta T/T = [I(I + 1)C-1/2 pi](1/2) =1.2(-0.3)(+0.4) x 10(-5) for HR 5127 and 1.9(-0.4)(+0.7) x 10(-5) for phi Herculis in the flat band approximation. The upper and lower limits represent a 68 percent confidence interval added in quadrature with a 10 percent calibration uncertainty
Extragalactic Submillimetric Surveys with BLAST
The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently conducted an extragalactic submillimetric survey of the Chandra Deep Field South region of unprecedented size, depth, and angular resolution in three wavebands centered at 250,
350, and 500 µm. BLAST wavelengths are chosen to study the Cosmic Infrared Background near its peak at 200 µm.
We find that most of the CIB at these wavelengths is contributed by galaxies detected at 24 µm by the MIPS instrument on Spitzer, and that the source counts distribution shows a population with strongly evolving density and luminosity. These results anticipate what can be expected from the surveys that will be conducted with the SPIRE instrument on the Herschel space observatory