4,235 research outputs found
Kohn-Sham calculations combined with an average pair-density functional theory
A recently developed formalism in which Kohn-Sham calculations are combined
with an ``average pair density functional theory'' is reviewed, and some new
properties of the effective electron-electron interaction entering in this
formalism are derived. A preliminary construction of a fully self-consitent
scheme is also presented in this framework.Comment: submitted to Int. J. Mod. Phys. B (proceedings of the 30th
International Workshop on Condensed Matter Theories
An automated system for lung nodule detection in low-dose computed tomography
A computer-aided detection (CAD) system for the identification of pulmonary
nodules in low-dose multi-detector helical Computed Tomography (CT) images was
developed in the framework of the MAGIC-5 Italian project. One of the main
goals of this project is to build a distributed database of lung CT scans in
order to enable automated image analysis through a data and cpu GRID
infrastructure. The basic modules of our lung-CAD system, a dot-enhancement
filter for nodule candidate selection and a neural classifier for
false-positive finding reduction, are described. The system was designed and
tested for both internal and sub-pleural nodules. The results obtained on the
collected database of low-dose thin-slice CT scans are shown in terms of free
response receiver operating characteristic (FROC) curves and discussed.Comment: 9 pages, 9 figures; Proceedings of the SPIE Medical Imaging
Conference, 17-22 February 2007, San Diego, California, USA, Vol. 6514,
65143
The interaction-strength interpolation method for main-group chemistry: benchmarking, limitations, and perspectives
We have tested the original interaction-strength-interpolation (ISI)
exchange-correlation functional for main group chemistry. The ISI functional is
based on an interpolation between the weak and strong coupling limits and
includes exact-exchange as well as the G\"orling-Levy second-order energy. We
have analyzed in detail the basis-set dependence of the ISI functional, its
dependence on the ground-state orbitals, and the influence of the
size-consistency problem. We show and explain some of the expected limitations
of the ISI functional (i.e. for atomization energies), but also unexpected
results, such as the good performance for the interaction energy of
dispersion-bonded complexes when the ISI correlation is used as a correction to
Hartree-Fock.Comment: 20 pages, 20 figure
Spectral Dependence of Polarized Radiation due to Spatial Correlations
We study the polarization of light emitted by spatially correlated sources.
We show that in general polarization acquires nontrivial spectral dependence
due to spatial correlations. The spectral dependence is found to be absent only
for a special class of sources where the correlation length scales as the
wavelength of light. We further study the cross correlations between two
spatially distinct points that are generated due to propagation. It is found
that such cross correlation leads to sufficiently strong spectral dependence of
polarization which can be measured experimentally.Comment: 5 pages, 4 figure
Computer-aided detection of pulmonary nodules in low-dose CT
A computer-aided detection (CAD) system for the identification of pulmonary
nodules in low-dose multi-detector helical CT images with 1.25 mm slice
thickness is being developed in the framework of the INFN-supported MAGIC-5
Italian project. The basic modules of our lung-CAD system, a dot enhancement
filter for nodule candidate selection and a voxel-based neural classifier for
false-positive finding reduction, are described. Preliminary results obtained
on the so-far collected database of lung CT scans are discussed.Comment: 3 pages, 4 figures; Proceedings of the CompIMAGE - International
Symposium on Computational Modelling of Objects Represented in Images:
Fundamentals, Methods and Applications, 20-21 Oct. 2006, Coimbra, Portuga
Predisposition to change is linked to job satisfaction: Assessing the mediation roles of workplace relation civility and insight
The globalization processes typical of liquid modern society require organizations to have high levels of flexibility, dynamism, and rapidity of change, testing the adaptability of workers with possible repercussions on well-being and productivity. Therefore, this study aimed to investigate the role of several psychological factors in favoring job satisfaction in a group of organizational workers (mean age = 46.24; SD = 9.99; 40.9% males and 59.1% females). Firstly, the impact of predisposition to change on job satisfaction through workplace relational civility (others with me) or insight orientation as independent mediating variables was analyzed. After that, this relationship was also studied by testing the effect that the simultaneous interaction of both mediators could have. Results show that workplace relational civility (others with me) significantly mediated the relationship between predisposition to change and job satisfaction, while no significance was found in the effect of insight when considered individually. However, the latter acquires greater relevance if placed in interaction with the other mediator, that is found to be the most proximal factor linking job satisfaction to the other more distal variables. Such findings might have a relevant role in strengthening preventive intervening, favoring positive results for greater well-being of both subjects and organizations
Vacuum Stability and Higgs Diphoton Decays in the MSSM
Current Higgs data at the Large Hadron Collider is compatible with a SM
signal at the 2 level, but the central value of the signal strength in
the diphoton channel is enhanced with respect to the SM expectation. If the
enhancement resides in the diphoton partial decay width, the data could be
accommodated in the Minimally Supersymmetric Standard Model (MSSM) with highly
mixed light staus. We revisit the issue of vacuum instability induced by large
mixing in the stau sector, including effects of a radiatively-corrected tau
Yukawa coupling. Further, we emphasize the importance of taking into account
the dependence in the stability bound. While the metastability of
the Universe constrains the possible enhancement in the Higgs to diphoton decay
width in the light stau scenario, an increase of the order of 50% can be
achieved in the region of large . Larger enhancements may be
obtained, but would require values of associated with
non-perturbative values of the tau Yukawa coupling at scales below the GUT
scale, thereby implying the presence of new physics beyond the MSSM.Comment: 25 pages, 7 figure
- …