305 research outputs found
Shear and Vorticity in a Combined Einstein-Cartan-Brans-Dicke Inflationary Lambda-Universe
A combined BCDE (Brans-Dicke and Einstein-Cartan) theory with lambda-term is
developed through Raychaudhuri's equation, for inflationary scenario. It
involves a variable cosmological constant, which decreases with time, jointly
with energy density, cosmic pressure, shear, vorticity, and Hubble's parameter,
while the scale factor, total spin and scalar field increase exponentially. The
post-inflationary fluid resembles a perfect one, though total spin grows, but
the angular speed does not (Berman, 2007d). Keywords: Cosmology; Einstein;
Brans-Dicke; Cosmological term; Shear; Spin; Vorticity; Inflation;
Einstein-Cartan; Torsion. PACS: 04.20.-q ; 98.80.-k ; 98.80.Bp ; 98.80.JkComment: 8 pages including front one. Published versio
General Relativistic Singularity-Free Cosmological Model
We "explain", using a Classical approach, how the Universe was created out of
"nothing", i.e., with no input of initial energy nor mass. The inflationary
phase, with exponential expansion, is accounted for, automatically, by our
equation of state for the very early Universe. This is a Universe with
no-initial infinite singularity of energy density.Comment: Astrophysics and Space Science, 321,157 (2009
Pryce-Hoyle Tensor in a Combined Einstein-Cartan-Brans-Dicke Model
In addition to introducing matter injection through a scalar field determined
by Pryce-Hoyle tensor, we also combine it with a BCDE
(Brans-Dicke-Einstein-Cartan) theory with lambdaterm developed earlier by
Berman(2008), for inflationary scenario. It involves a variable cosmological
constant, which decreases with time, jointly with energy density, cosmic
pressure, shear, vorticity, and Hubble's parameter, while the scale factor,
total spin and scalar field increase exponentially. The post-inflationary fluid
resembles a perfect one, though total spin grows, but not the angular speed
(Berman, 2007d). The Pryce-Hoyle tensor, which can measured by the number of
injected particles per unit proper volume and time, as well as shear and
vorticity, can be neglected in the aftermath of inflation ("no-hair").Comment: 16 pages including front cover. New version, accepted by
International Journal of Theoretical Physics. To be published soo
Report on Alaska Benefits and Costs of Exporting Alaska North Slope Crude Oil
Prepared for Alaska State Senate Finance CommitteeYe
Wavelets techniques for pointwise anti-Holderian irregularity
In this paper, we introduce a notion of weak pointwise Holder regularity,
starting from the de nition of the pointwise anti-Holder irregularity. Using
this concept, a weak spectrum of singularities can be de ned as for the usual
pointwise Holder regularity. We build a class of wavelet series satisfying the
multifractal formalism and thus show the optimality of the upper bound. We also
show that the weak spectrum of singularities is disconnected from the casual
one (denoted here strong spectrum of singularities) by exhibiting a
multifractal function made of Davenport series whose weak spectrum di ers from
the strong one
Structural neural networks subserving oculomotor function in first-episode schizophrenia
BACKGROUND: Smooth pursuit and antisaccade abnormalities are well documented in schizophrenia, but their neuropathological correlates remain unclear.
METHODS: In this study, we used statistical parametric mapping to investigate the relationship between oculomotor abnormalities and brain structure in a sample of first-episode schizophrenia patients (n = 27). In addition to conventional volumetric magnetic resonance imaging, we also used magnetization transfer ratio, a technique that allows more precise tissue characterization.
RESULTS: We found that smooth pursuit abnormalities were associated with reduced magnetization transfer ratio in several regions, predominantly in the right prefrontal cortex. Antisaccade errors correlated with gray matter volume in the right medial superior frontal cortex as measured by conventional magnetic resonance imaging but not with magnetization transfer ratio.
CONCLUSIONS: These preliminary results demonstrate that specific structural abnormalities are associated with abnormal eye movements in schizophrenia
The Seventh Data Release of the Sloan Digital Sky Survey
This paper describes the Seventh Data Release of the Sloan Digital Sky Survey
(SDSS), marking the completion of the original goals of the SDSS and the end of
the phase known as SDSS-II. It includes 11663 deg^2 of imaging data, with most
of the roughly 2000 deg^2 increment over the previous data release lying in
regions of low Galactic latitude. The catalog contains five-band photometry for
357 million distinct objects. The survey also includes repeat photometry over
250 deg^2 along the Celestial Equator in the Southern Galactic Cap. A
coaddition of these data goes roughly two magnitudes fainter than the main
survey. The spectroscopy is now complete over a contiguous area of 7500 deg^2
in the Northern Galactic Cap, closing the gap that was present in previous data
releases. There are over 1.6 million spectra in total, including 930,000
galaxies, 120,000 quasars, and 460,000 stars. The data release includes
improved stellar photometry at low Galactic latitude. The astrometry has all
been recalibrated with the second version of the USNO CCD Astrograph Catalog
(UCAC-2), reducing the rms statistical errors at the bright end to 45
milli-arcseconds per coordinate. A systematic error in bright galaxy photometr
is less severe than previously reported for the majority of galaxies. Finally,
we describe a series of improvements to the spectroscopic reductions, including
better flat-fielding and improved wavelength calibration at the blue end,
better processing of objects with extremely strong narrow emission lines, and
an improved determination of stellar metallicities. (Abridged)Comment: 20 pages, 10 embedded figures. Accepted to ApJS after minor
correction
Measurement of the Tau Branching Fractions into Leptons
Using data collected with the L3 detector near the Z resonance, corresponding
to an integrated luminosity of 150pb-1, the branching fractions of the tau
lepton into electron and muon are measured to be
B(tau->e nu nu) = (17.806 +- 0.104 (stat.) +- 0.076 (syst.)) %,
B(tau->mu nu nu) = (17.342 +- 0.110 (stat.) +- 0.067 (syst.)) %.
From these results the ratio of the charged current coupling constants of the
muon and the electron is determined to be g_mu/g_e = 1.0007 +- 0.0051. Assuming
electron-muon universality, the Fermi constant is measured in tau lepton decays
as G_F = (1.1616 +- 0.0058) 10^{-5} GeV^{-2}. Furthermore, the coupling
constant of the strong interaction at the tau mass scale is obtained as
alpha_s(m_tau^2) = 0.322 +- 0.009 (exp.) +- 0.015 (theory)
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