Why bother ?

Poster (2012, November 27)

Comment gérer la densification par les promoteurs, par les particuliers et par les outils d'urbanisme ?

Conference (2012, November 27)

A brief review of auroral emissions of the outer planets

Conference (2012, November 26)

Comparison Between Mornigstar Ratings And Traditional Performance Measures Ratings

E-print/Working paper (2012)

In this paper, we compare Morningstar ratings with those obtained using the same methodology of rating attribution with a set of commonly used performance measures. We look at three types of investment ... [more ▼]

In this paper, we compare Morningstar ratings with those obtained using the same methodology of rating attribution with a set of commonly used performance measures. We look at three types of investment horizons: 3-year, 5-year and 10-year ratings. Our analysis focuses on Open-End US Mutual Funds available in Morningstar Direct Database from which we create three sets of 16,617, 13,505 and 7,992 funds corresponding respectively to the three investment horizons analyzed. Our results show that Morningstar ratings are very close (correlation around 80%) to ratings obtained with Sharpe’s alpha, Jensen’s alpha, Four-factor alpha and Excess returns. And less significantly, we also observe that ratings given by the Sortino ratio, Sharpe MVaR, M-squared, Sharpe ratio, One-factor information ratio, Four-factor information ratio, Prospect ratio and Stutzer index are quite similar to Morningstar’s ratings (correlation lying between 70% and 78%). At the other end of the spectrum, however, ratings obtained with Annual return diverge widely from Morningstar ratings. We also analyse which explanatory variables can explain the differences between ratings computed with Morningstar as compared with the alternative performance measures using a probit regression. We find that Load adjustments, tax and risk included by Morningstar in the computation of MRAR are often determining. Expense ratio, Return Skewness and the three factors of the Fama-French model (Beta, Size load and Book-to-market loading) can be significant determinants depending on the performance measure analyzed and on the selected investment horizon. Fund characteristics such as Age, Fund size, Turnover rate and Manager tenure are not statistically significant in determining the differences in ratings. Besides, we analyze differences between ratings (in terms of number of STARs) and we confirm previous results (i.e. the link between Morningstar’s and the alternative performance measures, but also the explanatory capacity of the load for lots of differences between ratings). Finally, we test all possible combinations of our set of performance measures, and observe that Sharpe’s alpha, excess return, Sharpe MVaR, Four-factor alpha and Jensen’s alpha are part of the best combinations. As a conclusion, Morningstar ratings can be replicated using simple and traditional performance measures but the replication is less accurate when tax and loads features are important. Therefore, Morningstar data management and access bring the most of its ratings’ value added. [less ▲]

The nuclear physics of OHe

in Mankoc (Ed.) Proceedings of the 15th Bled Workshop "What Comes Beyond the Standard Models" (2012, November 24)

A recent composite-dark-matter scenario assumes that the dominant fraction of dark matter consists of O-helium (OHe) dark atoms, in which a lepton-like doubly charged particle O is bound with a primordial ... [more ▼]

A recent composite-dark-matter scenario assumes that the dominant fraction of dark matter consists of O-helium (OHe) dark atoms, in which a lepton-like doubly charged particle O is bound with a primordial helium nucleus. It liberates the physics of dark matter from unknown features of new physics, but it demands a deep understanding of the details of known nuclear and atomic physics, which are still unclear. Here, we consider in detail the physics of the binding of OHe to various nuclei of interest for direct dark matter searches. We show that standard quantum mechanics leads to bound states in the keV region, but does not seem to provide a simple mechanism that stabilizes them. The crucial role of a barrier in the OHe-nucleus potential is confirmed for such a stabilization. [less ▲]

FORMATION: "La mesure de l'efficacité de la prise en charge neuropsychologique. Pourquoi mesurer et comment faire?"

Conference (2012, November 24)

Integration/blending of external information into genetic/genomic evaluations

Diverse speeche and writing (2012)

Mechanical Processes of a Single Synthetic Molecular Machine Studied by AFM-based Force Spectroscopy

Doctoral thesis (2012)

Some biomolecules are able to generate directional forces by rectifying random thermal motions. This allows these molecular machines to perform mechanical tasks such as intracellular cargo transport or ... [more ▼]

Some biomolecules are able to generate directional forces by rectifying random thermal motions. This allows these molecular machines to perform mechanical tasks such as intracellular cargo transport or muscle contraction in plants and animals. Although some artificial molecular machines have been synthesized and used collectively to perform mechanical tasks, so far there have been no direct measurements of mechanical processes at the single-molecule level. Here we report measurements of the mechanical work performed by a synthetic molecule less than 5 nm long. We show that biased Brownian motion of the submolecular components in a hydrogen-bonded [2]rotaxane -a molecular ring threaded onto a molecular axle- can be harnessed to generate significant directional forces. We used the cantilever of an atomic force microscope to apply a mechanical load to the ring during single-molecule pulling-relaxing cycles. The ring was pulled along the axle, away from the thermodynamically favoured binding site, and was then found to travel back to this site against an external load of 30 pN. Using fluctuation theorems, we were able to relate the measurements of the work done at the level of individual molecules to the free energy change measured previously by ensemble measurements. Finally, we used dynamic single-molecule force spectroscopy to probe kinetic information of the interaction between the molecular ring and the preferred binding site. The results also demonstrate that AFM-based single-molecule force spectroscopy, which has been widely used to investigate the mechanochemical behaviour of (bio)macromolecules, can be applied to a molecule that is less than 5 nm in its extended form. [less ▲]

Intervention dans le cadre du Workshop Studien zur Struktur des Bewusstseins

Conference (2012, November 23)

Usages politiques du temps et visions de l'avenir, quelles conséquences sur l'action publique liée aux changements climatiques? Analyse de contenu sur plusieurs échelles politiques

Conference (2012, November 22)