Next-to-leading order gravitational spin1-spin2 coupling with Kaluza-Klein reduction

We use the recently proposed Kaluza-Klein (KK) reduction over the time dimension, within an effective field theory (EFT) approach, to calculate the next to leading order (NLO) gravitational spin1-spin2 interaction between two spinning compact objects. It is shown here that to NLO in the spin1-spin2 interaction, the reduced KK action within the stationary approximation is sufficient to describe the gravitational interaction, and that it simplifies calculation substantially. We also find here that the gravito-magnetic vector field defined within the KK decomposition of the metric mostly dominates the mediation of the interaction. Our results coincide with those calculated in the ADM Hamiltonian formalism, and we provide another explanation for the discrepancy with the result previously derived within the EFT approach, thus demonstrating clearly the equivalence of the ADM Hamiltonian formalism and the EFT action approach.Comment: 12 pages, revtex4-1, 3 figures; v2: reference added; v3: edited, section 3 elaborated; v4: publishe

Status of Global Analysis of Neutrino Oscillation Data

In this talk we discuss some details of the analysis of neutrino data and our present understanding of neutrino masses and mixing. This talk is based on hep-ph/0306001, hep-ph/0306226 and hep-ph/0404085.Comment: 10 pages, LaTeX file using ws-procs9x6, 6 figures included. Talk given by MCGG at the 5th Workshop on "Neutrino Oscillations and their Origin" (NOON2004), Tokyo, Japan, February 11-15, 200

Stem-Like Adaptive Aneuploidy and Cancer Quasispecies

We analyze and reinterpret experimental evidence from the literature to argue for an ability of tumor cells to self-regulate their aneuploidy rate. We conjecture that this ability is mediated by a diversification factor that exploits molecular mechanisms common to embryo stem cells and, to a lesser extent, adult stem cells, that is eventually reactivated in tumor cells. Moreover, we propose a direct use of the quasispecies model to cancer cells based on their significant genomic instability (i.e. aneuploidy rate), by defining master sequences lengths as the sum of all copy numbers of physically distinct whole and fragmented chromosomes. We compute an approximate error threshold such that any aneuploidy rate larger than the threshold would lead to a loss of fitness of a tumor population, and we confirm that highly aneuploid cancer populations already function with aneuploidy rates close to the estimated threshold

Nuclear quantum effects in solids using a colored-noise thermostat

We present a method, based on a non-Markovian Langevin equation, to include quantum corrections to the classical dynamics of ions in a quasi-harmonic system. By properly fitting the correlation function of the noise, one can vary the fluctuations in positions and momenta as a function of the vibrational frequency, and fit them so as to reproduce the quantum-mechanical behavior, with minimal a priori knowledge of the details of the system. We discuss the application of the thermostat to diamond and to ice Ih. We find that results in agreement with path-integral molecular dynamics can be obtained using only a fraction of the computational effort.Comment: submitted for publicatio

The Younger, the Better? Relative Age Effects at University

In this paper we estimate relative age effects in academic performance using a unique database of students at Bocconi University. The identification exploits school entry cut-off ages that generate up to 11 months difference between the youngest and the oldest students within each cohort. Our data allow to control for potential selection issues as well as for differences in cognitive ability, as measured by an attitudinal entry test. Contrary to most of the existing evidence for primary school children, we document that in university the youngest students perform better compared to their oldest peers, particularly in the most technical subjects. To rationalize this result we produce additional evidence on relative age effects in cognitive ability and in social behavior using a combination of data from Bocconi admission tests and from a survey on the social behavior of Italian first-year university students. We find that the youngest students in the cohort perform slightly better in cognitive tests and also appear to have less active social lives: they are less likely to do sports, go to discos and have love relationships. These results suggest that negative relative age effects in university performance might be generated by two mechanisms: (i) a profile of cognitive development that might be decreasing already around age 20; (ii) psychological relative age effects that lead the youngest in a cohort to develop social skills (self-esteem, leadership) at a slower pace. Younger students, thus, have less active social lives and devote more time to studying, as confirmed by additional evidence from the PISA study.education, relative age