202 research outputs found
Terminological challenges in the translation of science documentaries: a case-study
This article aims to describe some of the main terminological problems audiovisual translators have to face when dealing with the translation of science documentaries, specifically in the English-Catalan combination. The first section of the article presents some theoretical concepts which underlie this research and which are taken, for the most part, from Cabré's Communicative Theory of Terminology. Then, specific terminological problems audiovisual translators have to solve are described using the data provided by a corpus of four science documentaries lasting approximately 50 minutes each. These challenges include identifying a term, understanding a term, finding the right equivalent, dealing with the absence of an adequate equivalent, solving denominative variations, choosing between in vivo and in vitro terminology, and overcoming mistranscriptions
A note on the convergence of parametrised non-resonant invariant manifolds
Truncated Taylor series representations of invariant manifolds are abundant
in numerical computations. We present an aposteriori method to compute the
convergence radii and error estimates of analytic parametrisations of
non-resonant local invariant manifolds of a saddle of an analytic vector field,
from such a truncated series. This enables us to obtain local enclosures, as
well as existence results, for the invariant manifolds
Correlation of CMB with large-scale structure: II. Weak lensing
We investigate the correlation of gravitational lensing of the cosmic
microwave background (CMB) with several tracers of large-scale structure,
including luminous red galaxies (LRGs), quasars, and radio sources. The lensing
field is reconstructed based on the CMB maps from the Wilkinson Microwave
Anisotropy Probe (WMAP) satellite; the LRGs and quasars are observed by the
Sloan Digital Sky Survey (SDSS); and the radio sources are observed in the NRAO
VLA Sky Survey (NVSS). Combining all three large-scale structure samples, we
find evidence for a positive cross-correlation at the level
( for the SDSS samples and for NVSS); the
cross-correlation amplitude is times that expected for the WMAP
cosmological parameters. Our analysis extends other recent analyses in that we
carefully determine bias weighted redshift distribution of the sources, which
is needed for a meaningful cosmological interpretation of the detected signal.
We investigate contamination of the signal by Galactic emission, extragalactic
radio and infrared sources, thermal and kinetic Sunyaev-Zel'dovich effects, and
the Rees-Sciama effect, and find all of them to be negligible.Comment: 34 pages, 6 figures, matches PRD accepted versio
Correlation of CMB with large-scale structure: I. ISW Tomography and Cosmological Implications
We cross-correlate large scale structure (LSS) observations from a number of
surveys with CMB anisotropies from WMAP to investigate the Integrated
Sachs-Wolfe (ISW) effect as a function of redshift, covering z~0.1-2.5. Our
main goal is to go beyond reporting detections towards developing a reliable
likelihood analysis that allows one to determine cosmological constraints from
ISW observations. With this in mind we spend a considerable amount of effort in
determining the redshift-dependent bias and redshift distribution b(z)*dN/dz of
these samples by matching with spectroscopic observations where available, and
analyzing auto-power spectra and cross-power spectra between the samples. The
data sets we use are 2-Micron All Sky Survey (2MASS) samples, Sloan Digital Sky
Survey (SDSS) photometric Luminous Red Galaxies, SDSS photometric quasars and
NRAO VLA Sky Survey (NVSS) radio sources. We make a joint analysis of all
samples constructing a full covariance matrix, which we subsequently use for
cosmological parameter fitting. We report a 3.7 sigma detection of ISW
combining all the datasets. We combine the ISW likelihood function with weak
lensing of CMB and CMB power spectrum to constrain the equation of state of
dark energy and the curvature of the Universe. While ISW does not significantly
improve the constraints in the simplest 6-parameter flat Lambda CDM model, it
improves constraints on 7-parameter models with curvature by a factor of 3.2
(relative to WMAP alone) to Omega_K=-0.004^{+0.014}_{-0.020}, and with dark
energy equation of state by 15% to w=-1.01^{+0.30}_{-0.40}. (Abridged.)Comment: 35 pages, 18 figures, matches version to appear in PRD. Fixed bug in
MCMC interface, parameter values changed by <0.2 sigma. The likelihood code
can be downloaded at http://www.astro.princeton.edu/~shirley/ISW_WL.htm
New improved Moser-Trudinger inequalities and singular Liouville equations on compact surfaces
We consider a singular Liouville equation on a compact surface, arising from
the study of Chern-Simons vortices in a self dual regime. Using new improved
versions of the Moser-Trudinger inequalities (whose main feature is to be
scaling invariant) and a variational scheme, we prove new existence results.Comment: to appear in GAF
Photometric Selection of Emission Line Galaxies, Clustering Analysis and a Search for the ISW effect
We investigate the use of simple colour cuts applied to the SDSS optical
imaging to perform photometric selections of emission line galaxies out to z<1.
From colour-cuts using the SDSS g, r and i bands, we obtain mean photometric
redshifts of z=0.32+-0.08, z=0.44+-0.12 and z=0.65+-0.21. We further calibrate
our high redshift selection using spectroscopic observations with the AAOmega
spectrograph on the 4m Anglo-Australian Telescope (AAT), observing ~50-200
galaxy candidates in 4 separate fields. With just 1-hour of integration time
and with seeing of ~1.6", we successfully determined redshifts for ~65% of the
targeted candidates. We calculate the angular correlation functions of the
samples and find correlation lengths of r0=2.64 h-1 Mpc, r0=3.62 h-1 Mpc and
r0=5.88 h-1 Mpc for the low, mid and high redshift samples respectively.
Comparing these results with predicted dark matter clustering, we estimate the
bias parameter for each sample to be b=0.70, b=0.92 and b=1.46. We calculate
the 2-point redshift-space correlation function at z~0.6 and find a clustering
amplitude of s0=6.4 h-1 Mpc. Finally, we use our photometric sample to search
for the Integrated Sachs-Wolfe signal in the WMAP 5yr data. We cross-correlate
our three redshift samples with the WMAP W, V, Q and K bands and find an
overall trend for a positive signal similar to that expected from models.
However, the signal in each is relatively weak. Combining all three galaxy
samples we find a signal of wTg(<100')=0.20+-0.12 microK in the WMAP W-band, a
significance of 1.7sigma.Comment: 14 pages, 17 figures, submitted to MNRA
First-year Sloan Digital Sky Survey-II (SDSS-II) supernova results: consistency and constraints with other intermediate-redshift datasets
We present an analysis of the luminosity distances of Type Ia Supernovae from
the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey in conjunction with
other intermediate redshift (z<0.4) cosmological measurements including
redshift-space distortions from the Two-degree Field Galaxy Redshift Survey
(2dFGRS), the Integrated Sachs-Wolfe (ISW) effect seen by the SDSS, and the
latest Baryon Acoustic Oscillation (BAO) distance scale from both the SDSS and
2dFGRS. We have analysed the SDSS-II SN data alone using a variety of
"model-independent" methods and find evidence for an accelerating universe at
>97% level from this single dataset. We find good agreement between the
supernova and BAO distance measurements, both consistent with a
Lambda-dominated CDM cosmology, as demonstrated through an analysis of the
distance duality relationship between the luminosity (d_L) and angular diameter
(d_A) distance measures. We then use these data to estimate w within this
restricted redshift range (z<0.4). Our most stringent result comes from the
combination of all our intermediate-redshift data (SDSS-II SNe, BAO, ISW and
redshift-space distortions), giving w = -0.81 +0.16 -0.18(stat) +/- 0.15(sys)
and Omega_M=0.22 +0.09 -0.08 assuming a flat universe. This value of w, and
associated errors, only change slightly if curvature is allowed to vary,
consistent with constraints from the Cosmic Microwave Background. We also
consider more limited combinations of the geometrical (SN, BAO) and dynamical
(ISW, redshift-space distortions) probes.Comment: 13 pages, 7 figures, accepted for publication in MNRA
Some doubts on the validity of the foreground Galactic contribution subtraction from microwave anisotropies
The Galactic foreground contamination in CMBR anisotropies, especially from
the dust component, is not easily separable from the cosmological or
extragalactic component. In this paper, some doubts will be raised concerning
the validity of the methods used to date to remove Galactic dust emission in
order to show that none of them achieves its goal.
First, I review the recent bibliography on the topic and discuss critically
the methods of foreground subtraction: the cross-correlation with templates,
analysis assuming the spectral shape of the Galactic components, the "maximum
entropy method", "internal linear combination", and "wavelet-based high
resolution fitting of internal templates". Second, I analyse the galactic
latitude dependence from WMAP data. The frequency dependence is discussed with
the data in the available literature. The result is that all methods of
subtracting the Galactic contamination are inaccurate. The galactic latitude
dependence analysis or the frequency dependence of the anisotropies in the
range 50-250 GHz put a constraint on the maximum Galactic contribution in the
power spectrum to be less than a ~10% (68% C. L.) for a ~1 degree scale, and
possibly higher for larger scales.
The origin of most of the signal in the CMBR anisotropies is not Galactic. In
any case, the subtraction of the Galaxy is not accurate enough to allow a
"precision Cosmology"; other sources of contamination (extragalactic, solar
system) are also present.Comment: 24 pages, 1 figure, accepted to be published in J. Astrophys. Ast
RiskDiff: a web tool for the analysis of the difference due to risk and demographic factors for incidence or mortality data
Background Analysing the observed differences for incidence or mortality of a particular disease between two different situations (such as time points, geographical areas, gender or other social characteristics) can be useful both for scientific or administrative purposes. From an epidemiological and public health point of view, it is of great interest to assess the effect of demographic factors in these observed differences in order to elucidate the effect of the risk of developing a disease or dying from it. The method proposed by Bashir and Estève, which splits the observed variation into three components: risk, population structure and population size is a common choice at practice. Results A web-based application, called RiskDiff has been implemented (available at http://rht.iconcologia.net/riskdiff.htm webcite), to perform this kind of statistical analyses, providing text and graphical summaries. Code from the implemented functions in R is also provided. An application to cancer mortality data from Catalonia is used for illustration. Conclusions Combining epidemiological with demographical factors is crucial for analysing incidence or mortality from a disease, especially if the population pyramids show substantial differences. The tool implemented may serve to promote and divulgate the use of this method to give advice for epidemiologic interpretation and decision making in public health
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