2,785 research outputs found
Admiralty - Torts - A Permanently Moored Vessel Located in Navigable Waters, Though no Longer Involved in Commerce, Supplies the Necessary Maritime Nexus for Invocation of Admiralty Tort Jurisdiction Using the “Locality Plus” Test
Determination of some dominant parameters of the global dynamic sea surface topography from GEOS-3 altimetry
The 1977 altimetry data bank is analyzed for the geometrical shape of the sea surface expressed as surface spherical harmonics after referral to the higher reference model defined by GEM 9. The resulting determination is expressed as quasi-stationary dynamic SST. Solutions are obtained from different sets of long arcs in the GEOS-3 altimeter data bank as well as from sub-sets related to the September 1975 and March 1976 equinoxes assembled with a view to minimizing seasonal effects. The results are compared with equivalent parameters obtained from the hydrostatic analysis of sporadic temperature, pressure and salinity measurements of the oceans and the known major steady state current systems with comparable wavelengths. The most clearly defined parameter (the zonal harmonic of degree 2) is obtained with an uncertainty of + or - 6 cm. The preferred numerical value is smaller than the oceanographic value due to the effect of the correction for the permanent earth tide. Similar precision is achieved for the zonal harmonic of degree 3. The precision obtained for the fourth degree zonal harmonic reflects more closely the accuracy expected from the level of noise in the orbital solutions
Constraints on radiative decay of the 17-keV neutrino from COBE Measurements
It is shown that, for a nontrivial radiative decay channel of the 17-keV
neutrino, the photons would distort the microwave background radiation through
ionization of the universe. The constraint on the branching ratio of such
decays from COBE measurements is found to be more stringent than that from
other considerations. The limit on the branching ratio in terms of the Compton
parameter is for an
universe.Comment: 7 pages. (figures will be sent on request) (To appear in Phys. Rev.
D.
Insecurity for compact surfaces of positive genus
A pair of points in a riemannian manifold is secure if the geodesics
between the points can be blocked by a finite number of point obstacles;
otherwise the pair of points is insecure. A manifold is secure if all pairs of
points in are secure. A manifold is insecure if there exists an insecure
point pair, and totally insecure if all point pairs are insecure.
Compact, flat manifolds are secure. A standing conjecture says that these are
the only secure, compact riemannian manifolds. We prove this for surfaces of
genus greater than zero. We also prove that a closed surface of genus greater
than one with any riemannian metric and a closed surface of genus one with
generic metric are totally insecure.Comment: 37 pages, 11 figure
QUaD: A High-Resolution Cosmic Microwave Background Polarimeter
We describe the QUaD experiment, a millimeter-wavelength polarimeter designed
to observe the Cosmic Microwave Background (CMB) from a site at the South Pole.
The experiment comprises a 2.64 m Cassegrain telescope equipped with a
cryogenically cooled receiver containing an array of 62 polarization-sensitive
bolometers. The focal plane contains pixels at two different frequency bands,
100 GHz and 150 GHz, with angular resolutions of 5 arcmin and 3.5 arcmin,
respectively. The high angular resolution allows observation of CMB temperature
and polarization anisotropies over a wide range of scales. The instrument
commenced operation in early 2005 and collected science data during three
successive Austral winter seasons of observation.Comment: 23 pages, author list and text updated to reflect published versio
Lifestyle and metformin interventions have a durable effect to lower CRP and tPA levels in the diabetes prevention program except in those who develop diabetes.
OBJECTIVE: We evaluate whether lifestyle and metformin interventions used to prevent diabetes have durable effects on markers of inflammation and coagulation and whether the effects are influenced by the development of diabetes.
RESEARCH DESIGN AND METHODS: The Diabetes Prevention Program was a controlled clinical trial of 3,234 subjects at high risk for diabetes who were randomized to lifestyle, metformin, or placebo interventions for 3.4 years. Diabetes was diagnosed semiannually by fasting glucose and annually by oral glucose tolerance testing. In addition to baseline testing, anthropometry was performed every 6 months; fasting insulin yearly; and hs-CRP, tissue plasminogen activator (tPA), and fibrinogen at 1 year and end of study (EOS).
RESULTS: CRP and tPA levels were unchanged in the placebo group but fell in the lifestyle and metformin groups at 1 year and remained lower at EOS. These reductions were not seen in those who developed diabetes over the course of the study despite intervention. Fibrinogen was lower at 1 year in the lifestyle group. Differences in weight and weight change explained most of the influence of diabetes on the CRP response in the lifestyle group, but only partly in the placebo and metformin groups. Weight, insulin sensitivity, and hyperglycemia differences each accounted for the influence of diabetes on the tPA response.
CONCLUSIONS: Lifestyle and metformin interventions have durable effects to lower hs-CRP and tPA. Incident diabetes prevented these improvements, and this was accounted for by differences in weight, insulin resistance, and glucose levels
Comparing Cosmic Microwave Background Datasets
To extract reliable cosmic parameters from cosmic microwave background
datasets, it is essential to show that the data are not contaminated by
residual non-cosmological signals. We describe general statistical approaches
to this problem, with an emphasis on the case in which there are two datasets
that can be checked for consistency. A first visual step is the Wiener filter
mapping from one set of data onto the pixel basis of another. For more
quantitative analyses we develop and apply both Bayesian and frequentist
techniques. We define the ``contamination parameter'' and advocate the
calculation of its probability distribution as a means of examining the
consistency of two datasets. The closely related ``probability enhancement
factor'' is shown to be a useful statistic for comparison; it is significantly
better than a number of chi-squared quantities we consider. Our methods can be
used: internally (between different subsets of a dataset) or externally
(between different experiments); for observing regions that completely overlap,
partially overlap or overlap not at all; and for observing strategies that
differ greatly.
We apply the methods to check the consistency (internal and external) of the
MSAM92, MSAM94 and Saskatoon Ring datasets. From comparing the two MSAM
datasets, we find that the most probable level of contamination is 12%, with no
contamination only 1.05 times less probable, and 100% contamination strongly
ruled out at over 2 X 10^5 times less probable. From comparing the 1992 MSAM
flight with the Saskatoon data we find the most probable level of contamination
to be 50%, with no contamination only 1.6 times less probable and 100%
contamination 13 times less probable. [Truncated]Comment: LaTeX, 16 pages which include 16 figures, submitted to Phys. Rev.
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