225 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
Inter-comparison of phytoplankton functional type phenology metrics derived from ocean color algorithms and Earth System Models
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordOcean color remote sensing of chlorophyll concentration has revolutionized our understanding of the biology of the oceans. However, a comprehensive understanding of the structure and function of oceanic ecosystems requires the characterization of the spatio-temporal variability of various phytoplankton functional types (PFTs), which have differing biogeochemical roles. Thus, recent bio-optical algorithm developments have focused on retrieval of various PFTs. It is important to validate and inter-compare the existing PFT algorithms; however direct comparison of retrieved variables is non-trivial because in those algorithms PFTs are defined differently. Thus, it is more plausible and potentially more informative to focus on emergent properties of PFTs, such as phenology. Furthermore, ocean color satellite PFT data sets can play a pivotal role in informing and/or validating the biogeochemical routines of Earth System Models. Here, the phenological characteristics of 10 PFT satellite algorithms and 7 latest-generation climate models from the Coupled Model Inter-comparison Project (CMIP5) are inter-compared as part of the International Satellite PFT Algorithm Inter-comparison Project. The comparison is based on monthly satellite data (mostly SeaWiFS) for the 2003–2007 period. The phenological analysis is based on the fraction of microplankton or a similar variable for the satellite algorithms and on the carbon biomass due to diatoms for the climate models. The seasonal cycle is estimated on a per-pixel basis as a sum of sinusoidal harmonics, derived from the Discrete Fourier Transform of the variable time series. Peak analysis is then applied to the estimated seasonal signal and the following phenological parameters are quantified for each satellite algorithm and climate model: seasonal amplitude, percent seasonal variance, month of maximum, and bloom duration. Secondary/double blooms occur in many areas and are also quantified. The algorithms and the models are quantitatively compared based on these emergent phenological parameters. Results indicate that while algorithms agree to a first order on a global scale, large differences among them exist; differences are analyzed in detail for two Longhurst regions in the North Atlantic: North Atlantic Drift Region (NADR) and North Atlantic Subtropical Gyre West (NASW). Seasonal cycles explain the most variance in zonal bands in the seasonally-stratified subtropics at about 30° latitude in the satellite PFT data. The CMIP5 models do not reproduce this pattern, exhibiting higher seasonality in mid and high-latitudes and generally much more spatially homogeneous patterns in phenological indices compared to satellite data. Satellite data indicate a complex structure of double blooms in the Equatorial region and mid-latitudes, and single blooms on the poleward edges of the subtropical gyres. In contrast, the CMIP5 models show single annual blooms over most of the ocean except for the Equatorial band and Arabian Sea.NASAEuropean Space Agency (ESA
Combined analysis of the integrated Sachs-Wolfe effect and cosmological implications
We present a global measurement of the integrated Sachs-Wolfe (ISW) effect
obtained by cross-correlating all relevant large scale galaxy data sets with
the cosmic microwave background radiation map provided by the Wilkinson
Microwave Anisotropy Probe. With these measurements, the overall ISW signal is
detected at the ~ 4.5 sigma level. We also examine the cosmological
implications of these measurements, particularly the dark energy equation of
state w, its sound speed, and the overall curvature of the Universe. The flat
LCDM model is a good fit to the data and, assuming this model, we find that the
ISW data constrain Omega_m = 0.20 +0.19 -0.11 at the 95% confidence level. When
we combine our ISW results with the latest baryon oscillation and supernovae
measurements, we find that the result is still consistent with a flat LCDM
model with w = -1 out to redshifts z > 1.Comment: 24 pages, 15 figures. Version accepted by PRD. Improved quasar data,
revised parameter constraint
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
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
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
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
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