12,226 research outputs found
Towards a fully self-consistent spectral function of the nucleon in nuclear matter
We present a calculation of nuclear matter which goes beyond the usual
quasi-particle approximation in that it includes part of the off-shell
dependence of the self-energy in the self-consistent solution of the
single-particle spectrum. The spectral function is separated in contributions
for energies above and below the chemical potential. For holes we approximate
the spectral function for energies below the chemical potential by a
-function at the quasi-particle peak and retain the standard form for
energies above the chemical potential. For particles a similar procedure is
followed. The approximated spectral function is consistently used at all levels
of the calculation. Results for a model calculation are presented, the main
conclusion is that although several observables are affected by the inclusion
of the continuum contributions the physical consistency of the model does not
improve with the improved self-consistency of the solution method. This in
contrast to expectations based on the crucial role of self-consistency in the
proofs of conservation laws.Comment: 26 pages Revtex with 4 figures, submitted to Phys. Rev.
A skewer survey of the Galactic halo from deep CFHT and INT images
We study the density profile and shape of the Galactic halo using deep
multicolour images from the MENeaCS and CCCP projects, over 33 fields selected
to avoid overlap with the Galactic plane. Using multicolour selection and PSF
homogenization techniques we obtain catalogues of F stars (near-main sequence
turnoff stars) out to Galactocentric distances up to 60kpc. Grouping nearby
lines of sight, we construct the stellar density profiles through the halo in
eight different directions by means of photometric parallaxes. Smooth halo
models are then fitted to these profiles. We find clear evidence for a
steepening of the density profile power law index around R=20 kpc, from -2.50
+- 0.04 to -4.85 +- 0.04, and for a flattening of the halo towards the poles
with best-fit axis ratio 0.63 +- 0.02. Furthermore, we cannot rule out a mild
triaxiality (w>=0.8). We recover the signatures of well-known substructure and
streams that intersect our lines of sight. These results are consistent with
those derived from wider but shallower surveys, and augur well for upcoming,
wide-field surveys of comparable depth to our pencil beam surveys.Comment: 14 pages, 8 figures, 6 table
Finding halo streams with a pencil-beam survey: new wraps in the Sagittarius stream
We use data from two CFHT-MegaCam photometric pencil-beam surveys in the g'
and the r' bands to measure distances to the Sagittarius, the Palomar 5 and the
Orphan stream. We show that, using a cross-correlation algorithm to detect the
turnoff point of the main sequence, it is possible to overcome the main
limitation of a two-bands pencil-beam survey, namely the lack of adjacent
control-fields that can be used to subtract the foreground and background stars
to enhance the signal on the colour-magnitude diagrams (CMDs). We describe the
cross-correlation algorithm and its implementation. We combine the resulting
main sequence turnoff points with theoretical isochrones to derive photometric
distances to the streams. Our results (31 detections on the Sagittarius stream
and one each for the Palomar 5 and the Orphan streams) confirm the findings by
previous studies, expand the distance trend for the Sagittarius faint southern
branch and, for the first time, trace the Sagittarius faint branch of the
northern-leading arm out to 56 kpc. In addition, they show evidence for new
substructure: we argue that these detections trace the continuation of the
Sagittarius northern-leading arm into the southern hemisphere, and find a
nearby branch of the Sagittarius trailing wrap in the northern hemisphere.Comment: 16 pages, 15 figures, 2 table
Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment
Does training content matter? Differences between soft- and hard-skill trainings in transfer motivation
PurposeTransfer motivation has been identified as a pivotal factor influencing transfer of training. However, the role of training content has often been overlooked as explanatory variable for the rate of transfer motivation. This study aims to examine to what extent experiences in transfer motivation and its personal and contextual antecedents depend on whether the training content is soft or hard skill. To this end, this study used the perspective of the unified model of task-specific motivation.Design/methodology/approachA total of 1,122 trainees (462 soft skill and 660 hard skill) filled out a questionnaire representing the components of transfer motivation and its personal- and contextual antecedents. Data were analyzed by means of multi group structural equation modeling.FindingsThe results showed mean differences between soft- and hard-skill trainings in personal- and contextual antecedents of transfer motivation and for different types of transfer motivation. However, no differences in transfer intention were found.Practical implicationsThe outcomes provide insight as to what practitioners and trainers could do in training design and work environments to raise personal and contextual antecedents and to what extent a differentiation should be made between soft- and hard-skill trainings. This can eventually help them in raising transfer motivation among trainees.Originality/valueTo the best of the authors’ knowledge, this study is the first that examines whether experiences in personal and contextual antecedents of transfer motivation, transfer motivation and transfer intention differ for trainings consisting of different characteristics
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