Relativistic Hartree approach with exact treatment of vacuum polarization for finite nuclei

We study the relativistic Hartree approach with the exact treatment of the vacuum polarization in the Walecka sigma-omega model. The contribution from the vacuum polarization of nucleon-antinucleon field to the source term of the meson fields is evaluated by performing the energy integrals of the Dirac Green function along the imaginary axis. With the present method of the vacuum polarization in finite system, the total binding energies and charge radii of 16O and 40Ca can be reproduced. On the other hand, the level-splittings in the single-particle level, in particular the spin-orbit splittings, are not described nicely because the inclusion of vacuum effect provides a large effective mass with small meson fields. We also show that the derivative expansion of the effective action which has been used to calculate the vacuum contribution for finite nuclei gives a fairly good approximation.Comment: 15 pages, 8 figure

Synthesis of Solution-Phase Phosphoramidite and Phosphite Ligand Libraries and Their In Situ Screening in the Rhodium-Catalyzed Asymmetric Addition of Arylboronic Acids

Herein, we report the automated parallel synthesis of solution-phase libraries of phosphoramidite ligands for the development of enantioselective catalysts. The ligand libraries are screened in situ in the asymmetric rhodium-catalyzed addition of arylboronic acids to aldehydes and imines. It is shown that the described methodology results in the straightforward discovery of leads for highly efficient enantioselective catalysts.

Sputum Induction in Children Is Feasible and Useful in a Bustling General Hospital Practice

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The Jeroen Bosch Hospital funded this study.Peer reviewedPublisher PD

Testing the Gaussian Copula Hypothesis for Financial Assets Dependences

Using one of the key property of copulas that they remain invariant under an arbitrary monotonous change of variable, we investigate the null hypothesis that the dependence between financial assets can be modeled by the Gaussian copula. We find that most pairs of currencies and pairs of major stocks are compatible with the Gaussian copula hypothesis, while this hypothesis can be rejected for the dependence between pairs of commodities (metals). Notwithstanding the apparent qualification of the Gaussian copula hypothesis for most of the currencies and the stocks, a non-Gaussian copula, such as the Student's copula, cannot be rejected if it has sufficiently many ``degrees of freedom''. As a consequence, it may be very dangerous to embrace blindly the Gaussian copula hypothesis, especially when the correlation coefficient between the pair of asset is too high as the tail dependence neglected by the Gaussian copula can be as large as 0.6, i.e., three out five extreme events which occur in unison are missed.Comment: Latex document of 43 pages including 14 eps figure

The role of self-concept content, certainty and stability in academic procrastination

Academic procrastination has been associated with a variety of negative outcomes. While theorists have proposed that those with an unstable self-concept engage in procrastination due to the fear that they will be unable to meet the required standard, a systematic review conducted as part of the present study (Chapter 2) revealed that all research pertaining to the self-concept in academic procrastination has been correlational, thereby limiting the validity of such theories. As such, the present study employed an experimental design to investigate the self-concept of academic procrastinators (Chapter 3). Ninety-nine undergraduate students completed trait, symptom and academic procrastination inventories as well as measures of state-based affect and cognition, and self-concept content, certainty and stability before and after receiving feedback for a writing task. Compared to low procrastinators, high procrastinators described a self-concept characterised by a greater number of negative and procrastination-related attributes, higher levels of fear of negative evaluation, lower levels of self-concept clarity, self-efficacy and self-esteem and more severe symptoms of depression, anxiety and stress. Furthermore, both the content and certainty associated with procrastinators’ self-concept descriptions changed significantly as a result of receiving randomly allocated feedback for a writing task. While high procrastinators reported significant improvements to their self-concept after receiving a positive evaluation, low procrastinators showed a more positive self-concept which did not change after feedback. These results provide the first empirical evidence for the presence of an unstable self-concept in academic procrastinators, providing support for the aforementioned theory and emphasising the importance of addressing self-concept stability in the psychological treatment of academic procrastination. Further research may investigate mindfulness-based interventions