727 research outputs found
La metodología de la investigación en Traductología
Empirical research methods in Translation Studies have been used in Spain for a decade. A glimpse of the most recent studies carried out in our country is given, as well as the actual trends in research. A research methodology based on the scientific method is proposed, and a research design to study the acquisition of translation competence in trainees is presented, including three original measuring instruments created for the study: the first instrument measures the translation notions of the students; the second one measures students' performance when faced with translation problems; and the third one measures performance regarding translation errors
The magnetic environment in the central region of nearby galaxies
The central regions of galaxies harbor some of the most extreme physical
phenomena, including dense stellar clusters, non-circular motions of molecular
clouds and strong and pervasive magnetic field structures. In particular, radio
observations have shown that the central few hundred parsecs of our Galaxy has
a striking magnetic field configuration. It is not yet clear whether these
magnetic structures are unique to our Milky Way or a common feature of all
similar galaxies. Therefore, we report on (a) a new radio polarimetric survey
of the central 200 pc of the Galaxy to better characterize the magnetic field
structure and (b) a search for large-scale and organized magnetized structure
in the nuclear regions of nearby galaxies using data from the Very Large Array
(VLA) archive. The high angular resolution of the VLA allows us to study the
central 1 kpc of the nearest galaxies to search for magnetized nuclear features
similar to what is detected in our own Galactic center. Such magnetic features
play a important role in the nuclear regions of galaxies in terms of gas
transport and the physical conditions of the interstellar medium in this
unusual region of galaxies.Comment: 8 pages; Proceedings for "The Universe under the Microscope" (AHAR
2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal
of Physics: Conference Series by Institute of Physics Publishing, R.
Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.
The social value of a QALY : raising the bar or barring the raise?
Background: Since the inception of the National Institute for Health and Clinical Excellence (NICE) in England,
there have been questions about the empirical basis for the cost-per-QALY threshold used by NICE and whether
QALYs gained by different beneficiaries of health care should be weighted equally. The Social Value of a QALY
(SVQ) project, reported in this paper, was commissioned to address these two questions. The results of SVQ were
released during a time of considerable debate about the NICE threshold, and authors with differing perspectives
have drawn on the SVQ results to support their cases. As these discussions continue, and given the selective use of
results by those involved, it is important, therefore, not only to present a summary overview of SVQ, but also for
those who conducted the research to contribute to the debate as to its implications for NICE.
Discussion: The issue of the threshold was addressed in two ways: first, by combining, via a set of models, the
current UK Value of a Prevented Fatality (used in transport policy) with data on fatality age, life expectancy and
age-related quality of life; and, second, via a survey designed to test the feasibility of combining respondents’
answers to willingness to pay and health state utility questions to arrive at values of a QALY. Modelling resulted in
values of £10,000-£70,000 per QALY. Via survey research, most methods of aggregating the data resulted in values
of a QALY of £18,000-£40,000, although others resulted in implausibly high values. An additional survey, addressing
the issue of weighting QALYs, used two methods, one indicating that QALYs should not be weighted and the
other that greater weight could be given to QALYs gained by some groups.
Summary: Although we conducted only a feasibility study and a modelling exercise, neither present compelling
evidence for moving the NICE threshold up or down. Some preliminary evidence would indicate it could be
moved up for some types of QALY and down for others. While many members of the public appear to be open to
the possibility of using somewhat different QALY weights for different groups of beneficiaries, we do not yet have
any secure evidence base for introducing such a system
Electromechanics of charge shuttling in dissipative nanostructures
We investigate the current-voltage (IV) characteristics of a model
single-electron transistor where mechanical motion, subject to strong
dissipation, of a small metallic grain is possible. The system is studied both
by using Monte Carlo simulations and by using an analytical approach. We show
that electromechanical coupling results in a highly nonlinear IV-curve. For
voltages above the Coulomb blockade threshold, two distinct regimes of charge
transfer occur: At low voltages the system behave as a static asymmetric double
junction and tunneling is the dominating charge transfer mechanism. At higher
voltages an abrupt transition to a new shuttle regime appears, where the grain
performs an oscillatory motion back and forth between the leads. In this regime
the current is mainly mediated by charges that are carried on the grain as it
moves from one lead to the other.Comment: 8 pages, 10 figures, final version to be published in PR
Low frequency current noise of the single-electron shuttle
Coupling between electronic and mechanical degrees of freedom in a single
electron shuttle system can cause a mechanical instability leading to shuttle
transport of electrons between external leads. We predict that the resulting
low frequency current noise can be enhanced due to amplitude fluctuations of
the shuttle oscillations. Moreover, at the onset of mechanical instability a
pronounced peak in the low frequency noise is expected.Comment: 14 pages, 3 figures, 1 tabl
Submillimeter galaxies behind the Bullet Cluster (1E 0657-56)
Clusters of galaxies are effective gravitational lenses able to magnify
background galaxies and making it possible to probe the fainter part of the
galaxy population. Submillimeter galaxies, which are believed to be
star-forming galaxies at typical redshifts of 2 to 3, are a major contaminant
to the extended Sunyaev-Zeldovich (SZ) signal of galaxy clusters. For a proper
quantification of the SZ signal the contribution of submillimeter galaxies
needs to be quantified. The aims of this study are to identify submillimeter
sources in the field of the Bullet Cluster (1E 0657-56), a massive cluster of
galaxies at z~0.3, measure their flux densities at 870 micron, and search for
counterparts at other wavelengths to constrain their properties. We carried out
deep observations of the submillimeter continuum emission at 870 micron using
the Large APEX BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment
(APEX) telescope. Several numerical techniques were used to quantify the noise
properties of the data and extract sources. In total, seventeen sources were
found. Thirteen of them lie in the central 10 arcminutes of the map, which has
a pixel sensitivity of 1.2 mJy per 22 arcsec beam. After correction for flux
boosting and gravitational lensing, the number counts are consistent with
published submm measurements. Nine of the sources have infrared counterparts in
Spitzer maps. The strongest submm detection coincides with a source previously
reported at other wavelengths, at an estimated redshift z~2.7. If the submm
flux arises from two images of a galaxy magnified by a total factor of 75, as
models have suggested, its intrinsic flux would be around 0.6 mJy, consistent
with an intrinsic luminosity below 10^12 L_sun.Comment: Accepted by A&A, 15 pages, 11 figure
Strong fragmentation of low-energy electromagnetic excitation strength in Sn
Results of nuclear resonance fluorescence experiments on Sn are
reported. More than 50 transitions with MeV were
detected indicating a strong fragmentation of the electromagnetic excitation
strength. For the first time microscopic calculations making use of a complete
configuration space for low-lying states are performed in heavy odd-mass
spherical nuclei. The theoretical predictions are in good agreement with the
data. It is concluded that although the E1 transitions are the strongest ones
also M1 and E2 decays contribute substantially to the observed spectra. In
contrast to the neighboring even Sn, in Sn the
component of the two-phonon quintuplet built on top of
the 1/2 ground state is proved to be strongly fragmented.Comment: 4 pages, 3 figure
Search for the electric dipole excitations to the multiplet in Sn
The odd-mass Sn nucleus was investigated in nuclear resonance
fluorescence experiments up to an endpoint energy of the incident photon
spectrum of 4.1 MeV at the bremsstrahlung facility of the Stuttgart University.
More than 50 mainly hitherto unknown levels were found. From the measurement of
the scattering cross sections model independent absolute electric dipole
excitation strengths were extracted. The measured angular distributions
suggested the spins of 11 excited levels. Quasi-particle phonon model
calculations including a complete configuration space were performed for the
first time for a heavy odd-mass spherical nucleus. These calculations give a
clear insight in the fragmentation and distribution of the , , and
excitation strength in the low energy region. It is proven that the
component of the two-phonon quintuplet built on
top of the ground state is strongly fragmented. The theoretical
calculations are consistent with the experimental data.Comment: 10 pages, 5 figure
Ribosome Display Selection of a Murine IgG1 Fab Binding Affibody Molecule Allowing Species Selective Recovery Of Monoclonal Antibodies
Affinity reagents recognizing constant parts of antibody molecules are invaluable tools in immunotechnology applications, including purification, immobilization, and detection of immunoglobulins. In this article, murine IgG1, the primary isotype of monoclonal antibodies (mAbs) was used as target for selection of novel binders from a combinatorial ribosome display (RD) library of 1011 affibody molecules. Four rounds of selection using three different mouse IgG1 mAbs as alternating targets resulted in the identification of binders with broad mIgG1 recognition and dissociation constants (KD) in the low nanomolar to low micromolar range. For one of the binders, denoted Zmab25, competition in binding to full length mIgG1 by a streptococcal protein G (SPG) fragment and selective affinity capture of mouse IgG1 Fab fragments after papain cleavage of a full mAb suggest that an epitope functionally overlapping with the SPG-binding site in the CH1 domain of mouse IgG1 had been addressed. Interestingly, biosensor-based binding experiments showed that neither human IgG1 nor bovine Ig, the latter present in fetal bovine serum (FBS) was recognized by Zmab25. This selective binding profile towards murine IgG1 was successfully exploited in species selective recovery of two different mouse mAbs from complex samples containing FBS, resembling a hybridoma culture supernatant
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