7,201 research outputs found
Operator product expansions as a consequence of phase space properties
The paper presents a model-independent, nonperturbative proof of operator
product expansions in quantum field theory. As an input, a recently proposed
phase space condition is used that allows a precise description of point field
structures. Based on the product expansions, we also define and analyze normal
products (in the sense of Zimmermann).Comment: v3: minor wording changes, as to appear in J. Math. Phys.; 12 page
Detecting planets in protoplanetary disks: A prospective study
We investigate the possibility to find evidence for planets in circumstellar
disks by infrared and submillimeter interferometry. We present simulations of a
circumstellar disk around a solar-type star with an embedded planet of 1
Jupiter mass. The three-dimensional (3D) density structure of the disk results
from hydrodynamical simulations. On the basis of 3D radiative transfer
simulations, images of this system were calculated. The intensity maps provide
the basis for the simulation of the interferometers VLTI (equipped with the
mid-infrared instrument MIDI) and ALMA. While MIDI/VLTI will not provide the
possibility to distinguish between disks with or without a gap on the basis of
visibility measurements, ALMA will provide the necessary basis for a direct gap
detection.Comment: 5 page
Interferometric Detection of Planets/Gaps in Protoplanetary Disks
We investigate the possibility to find evidence for planets in circumstellar
disks by infrared and submillimeter interferometry. Hydrodynamical simulations
of a circumstellar disk around a solar-type star with an embedded planet of 1
Jupiter mass are presented. On the basis of 3D radiative transfer simulations,
images of this system are calculated. These intensity maps provide the basis
for the simulation of the interferometers VLTI (equipped with the mid-infrared
instrument MIDI) and ALMA. While ALMA will provide the necessary basis for a
direct gap and therefore indirect planet detection, MIDI/VLTI will provide the
possibility to distinguish between disks with or without accretion on the
central star on the basis of visibility measurements.Comment: 4 pages, TeX (or Latex, etc); to appear in proceedings of "Scientific
Frontiers in Research on Extrasolar Planets
Statistical Modeling of Epistasis and Linkage Decay using Logic Regression
Logic regression has been recognized as a tool that can identify and model non-additive genetic interactions using Boolean logic groups. Logic regression, TASSEL-GLM and SAS-GLM were compared for analytical precision using a previously characterized model system to identify the best genetic model explaining epistatic interaction for vernalization-sensitivity in barley. A genetic model containing two molecular markers identified in vernalization response in barley was selected using logic regression while both TASSEL-GLM and SAS-GLM included spurious associations in their models. The results also suggest the logic regression can be used to identify dominant/recessive relationships between epistatic alleles through its use of conjugate operators
Estsitalopraami efektiivsus depressiooni ravis võrrelduna konventsionaalsete selektiivsete serotoniini tagasihaarde inhibiitorite ja venlafaksiin XRiga: metaanalüüs
Estsitalopraam on kõige selektiivsem selektiivsete serotoniini tagasihaarde inhibiitorite rühma kuuluv antidepressant. Varasemad uuringud on näidanud, et estsitalopraam on oma toimelt tõhusam kui tsitalopraam. Artiklis on antud ülevaade metaanalüüsi uuringutest, milles estsitalopraami võrreldi teiste antidepressantidega (tsitalopraam, fluoksetiin, paroksetiin, sertraliin ja venlafaksiin XR). Estsitalopraam oli efektiivsem kui kõik teised võrdlusravimid nii üldise raviefekti, ravile reageerimise määra kui ka remissiooni saavutamise määra poolest. Eri ravimirühmade analüüs näitas, et estsitalopraam oli oluliselt tõhusam kui konventsionaalsed SSRId ja võrdväärne venlafaksiiniga, ehkki uuringu üldised tulemused ei näita tingimata, et estsitalopraam oleks oluliselt efektiivsem kui iga SSRI eraldi. Sarnased tulemused leiti ka raske depressiooniga patsientide seas.
Eesti Arst 2006; 85 (11): 739–75
Grain size limits derived from 3.6 {\mu}m and 4.5 {\mu}m coreshine
Recently discovered scattered light from molecular cloud cores in the
wavelength range 3-5 {\mu}m (called "coreshine") seems to indicate the presence
of grains with sizes above 0.5 {\mu}m. We aim to analyze 3.6 and 4.5 {\mu}m
coreshine from molecular cloud cores to probe the largest grains in the size
distribution. We analyzed dedicated deep Cycle 9 Spitzer IRAC observations in
the 3.6 and 4.5 {\mu}m bands for a sample of 10 low-mass cores. We used a new
modeling approach based on a combination of ratios of the two background- and
foreground-subtracted surface brightnesses and observed limits of the optical
depth. The dust grains were modeled as ice-coated silicate and carbonaceous
spheres. We discuss the impact of local radiation fields with a spectral slope
differing from what is seen in the DIRBE allsky maps. For the cores L260,
ecc806, L1262, L1517A, L1512, and L1544, the model reproduces the data with
maximum grain sizes around 0.9, 0.5, 0.65, 1.5, 0.6, and > 1.5 {\mu}m,
respectively. The maximum coreshine intensities of L1506C, L1439, and L1498 in
the individual bands require smaller maximum grain sizes than derived from the
observed distribution of band ratios. Additional isotropic local radiation
fields with a spectral shape differing from the DIRBE map shape do not remove
this discrepancy. In the case of Rho Oph 9, we were unable to reliably
disentangle the coreshine emission from background variations and the strong
local PAH emission. Considering surface brightness ratios in the 3.6 and 4.5
{\mu}m bands across a molecular cloud core is an effective method of
disentangling the complex interplay of structure and opacities when used in
combination with observed limits of the optical depth.Comment: 23 pages, 18 figures, accepted for publication in A&
The Arecibo L-band Feed Array Zone of Avoidance Survey I: Precursor Observations through the Inner and Outer Galaxy
The Arecibo L-band Feed Array (ALFA) is being used to conduct a low-Galactic
latitude survey, to map the distribution of galaxies and large-scale structures
behind the Milky Way through detection of galaxies' neutral hydrogen (HI) 21-cm
emission. This Zone of Avoidance (ZOA) survey finds new HI galaxies which lie
hidden behind the Milky Way, and also provides redshifts for partially-obscured
galaxies known at other wavelengths. Before the commencement of the full
survey, two low-latitude precursor regions were observed, totalling 138 square
degrees, with 72 HI galaxies detected. Detections through the inner Galaxy
generally have no cataloged counterparts in any other waveband, due to the
heavy extinction and stellar confusion. Detections through the outer Galaxy are
more likely to have 2MASS counterparts. We present the results of these
precursor observations, including a catalog of the detected galaxies, with
their HI parameters. The survey sensitivity is well described by a flux- and
linewidth-dependent signal-to-noise ratio of 6.5. ALFA ZOA galaxies which also
have HI measurements in the literature show good agreement between our
measurements and previous work. The inner Galaxy precursor region was chosen to
overlap the HI Parkes Zone of Avoidance Survey so ALFA performance could be
quickly assessed. The outer Galaxy precursor region lies north of the Parkes
sky. Low-latitude large-scale structure in this region is revealed, including
an overdensity of galaxies near l = 183 deg and between 5000 - 6000 km/s in the
ZOA. The full ALFA ZOA survey will be conducted in two phases: a shallow survey
using the observing techniques of the precursor observations, and also a deep
phase with much longer integration time, with thousands of galaxies predicted
for the final catalog.Comment: 26 pages, 7 figures, 2 tables, Astronomical Journal accepte
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