Uniform Poincare inequalities for unbounded conservative spin systems: The non-interacting case

We prove a uniform Poincare' inequality for non-interacting unbounded spin systems with a conservation law, when the single-site potential is a bounded perturbation of a convex function. The result is then applied to Ginzburg-Landau processes to show diffusive scaling of the associated spectral gap.Comment: 19 pages, revised version, to appear in Stoch. Proc. App

Social desirability bias in self-reported wellbeing measures. Evidence from an online survey

Social desirability seems to enhance well-being measures because individuals tend to increase the degree of their satisfaction and happiness resulting in response artifacts and in a serious threat to the validity of self-reported data. This paper explores social desirability bias in self-reported subjective well-being, controlling for several sociodemographic variables such as gender, age, education, marital/relationship status, and employment status. This is in order to test whether social desirability has incremental validity in predicting some well-being measures. Three different facets of well-being are proposed which deal with subjective happiness, general life satisfaction, and gratitude and loneliness, respectively regarded as a positive and negative emotional response. Through a web-based survey a convenience sample of 170 participants completed an online questionnaire including measures of social desirability, subjective happiness, life satisfaction, gratitude, and loneliness. Correlation analyses and two-step hierarchical multiple regression analyses were conducted. All well-being measures show modest significant correlations with social desirability ranging from 0.235 to 0.309, except subjective happiness. Social desirability accounted for from about 3% to 6% of the variance of these measures, after controlling for socio-demographic variables. Social desirability seems thus to play little role in well-being self-report measures, as revealed by previous studies. Some limitations are discussed, as well as issues about social desirability bias in online investigation

RR Lyrae variables in Galactic globular clusters - I: The observational scenario

In this paper we revisit observational data concerning RR Lyrae stars in Galactic globular clusters, presenting frequency histograms of fundamentalized periods for the 32 clusters having more than 12 pulsators with well recognized period and pulsation mode. One finds that the range of fundamentalized periods covered by the variables in a given cluster remains fairly constant in varying the cluster metallicity all over the metallicity range spanned by the cluster sample, with the only two exceptions given by M15 and NGC6441. We conclude that the width in temperature of the RR Lyrae instability strip appears largely independent of the cluster metallicity. At the same time, it appears that the fundamentalized periods are not affected by the predicted variation of pulsators luminosity with metal abundance, indicating the occurrence of a correlated variation in the pulsator mass. We discuss mean periods in a selected sample of statistically significant "RR rich" clusters with no less than 10 RRab and 5 RRc variables. One finds a clear evidence for the well known Oosterhoff dichotomy in the mean period of ab-type variables, together with a similarly clear evidence for a constancy of the mean fundamentalized period in passing from Oosterhoff type II to type I clusters. On this basis, the origin of the Oosterhoff dichotomy is discussed, presenting evidence against a strong dependence of the RR Lyrae luminosity on the metal content.Comment: 9 pages, 6 figures. Accepted for publication on A&

Exchange Rates and Monetary Policy in Open Economies: The Experience of Chile in the Nineties

This paper provides an empirical characterization of the conduct of monetary policy in a small open economy. In particular, using as a case study the Chilean inflation-targeting experience of the nineties, we assess the roles of the exchange rate and output in the determination of the policy interest rate. We conclude that Chile adopted a gradual approach to targeting inflation. This means, in practice, that the central bank modified its policy instrument —the interest rate— whenever expected inflation deviated from its target, but with some concern about output. In this context, we find evidence that the monetary authorities also reacted to real exchange rate misalignments. This reaction was comparatively larger than the one found in developed economies. Finally, the evidence, although not conclusive, suggests that there was a non-linear response to exchange rate misalignments: the central bank reacted more strongly to large deviations than to small ones.

Towards a quantitative measure of rareness

Within the context of detection of incongruent events, an often overlooked aspect is how a system should react to the detection. The set of all the possible actions is certainly conditioned by the task at hand, and by the embodiment of the artificial cognitive system under consideration. Still, we argue that a desirable action that does not depend from these factors is to update the internal model and learn the new detected event. This paper proposes a recent transfer learning algorithm as the way to address this issue. A notable feature of the proposed model is its capability to learn from small samples, even a single one. This is very desirable in this context, as we cannot expect to have too many samples to learn from, given the very nature of incongruent events. We also show that one of the internal parameters of the algorithm makes it possible to quantitatively measure incongruence of detected events. Experiments on two different datasets support our claim

Stellar populations in the dwarf spheroidal galaxy Leo I

We present a detailed study of the color magnitude diagram (CMD) of the dwarf spheroidal galaxy Leo I, based on archival Hubble Space Telescope data. Our photometric analysis, confirming previous results on the brighter portion of the CMD, allow us to obtain an accurate sampling of the stellar populations also at the faint magnitudes corresponding to the Main Sequence. By adopting a homogeneous and consistent theoretical scenario for both hydrogen and central helium-burning evolutionary phases, the various features observed in the CMD are interpreted and reliable estimations for both the distance modulus and the age(s) for the main stellar components of Leo I are derived. More in details, from the upper luminosity of the Red Giant Branch and the lower luminosity of the Subgiant Branch we simultaneously constrain the galaxy distance and the age of the oldest stellar population in Leo I. In this way we obtain a distance modulus (m-M)_V=22.00$\pm$0.15 mag and an age of 10--15 Gyr or 9--13 Gyr, adopting a metallicity Z=0.0001 and 0.0004, respectively. The reliability of this distance modulus has been tested by comparing the observed distribution of the Leo I anomalous Cepheids in the period-magnitude diagram with the predicted boundaries of the instability strip, as given by convective pulsating models.Comment: 19 pages, 3 tables, 14 figures To be published in A