NODDI-SH: a computational efficient NODDI extension for fODF estimation in diffusion MRI

Diffusion Magnetic Resonance Imaging (DMRI) is the only non-invasive imaging technique which is able to detect the principal directions of water diffusion as well as neurites density in the human brain. Exploiting the ability of Spherical Harmonics (SH) to model spherical functions, we propose a new reconstruction model for DMRI data which is able to estimate both the fiber Orientation Distribution Function (fODF) and the relative volume fractions of the neurites in each voxel, which is robust to multiple fiber crossings. We consider a Neurite Orientation Dispersion and Density Imaging (NODDI) inspired single fiber diffusion signal to be derived from three compartments: intracellular, extracellular, and cerebrospinal fluid. The model, called NODDI-SH, is derived by convolving the single fiber response with the fODF in each voxel. NODDI-SH embeds the calculation of the fODF and the neurite density in a unified mathematical model providing efficient, robust and accurate results. Results were validated on simulated data and tested on \textit{in-vivo} data of human brain, and compared to and Constrained Spherical Deconvolution (CSD) for benchmarking. Results revealed competitive performance in all respects and inherent adaptivity to local microstructure, while sensibly reducing the computational cost. We also investigated NODDI-SH performance when only a limited number of samples are available for the fitting, demonstrating that 60 samples are enough to obtain reliable results. The fast computational time and the low number of signal samples required, make NODDI-SH feasible for clinical application

Absolute determination of D_s branching ratios and f_{D_s} extraction at a neutrino factory

A method for a direct measurement of the exclusive D_s branching ratios and of the decay constant f_{D_s} with a systematical error better than 5% is presented. The approach is based on the peculiar vertex topology of the anti-neutrino induced diffractive charm events. The statistical accuracy achievable with a neutrino factory is estimated

Religious attitudes and home bias: theory and evidence from a pilot study

This paper examines the relationship between religion and home bias. We propose a simple theoretical framework that suggests that countries interacting via their representative individuals might show a certain degree of religion-driven international altruism that in turn affects trade. We test these predictions exploiting data from a survey on religious attitudes and individuals' preferences over consumption of home-produced versus foreign goods that we designed and carried out in 15 different countries. We find evidence that religious openness and home bias are negatively correlated. This appears to provide some support to the hypothesis that religious openness, through trust and altruism, may have a pro-trade effect.

Search for the Decays B-S(0) -> tau(+) tau(-) and B-0 -> tau(+) tau(-)

A search for the rare decays B0s→τ+τ− and B0→τ+τ− is performed using proton–proton collision data collected with the LHCb detector. The data sample corresponds to an integrated luminosity of 3 fb−1 collected in 2011 and 2012. The τ leptons are reconstructed through the decay τ−→π−π+π−ντ. Assuming no contribution from B0→τ+τ− decays, an upper limit is set on the branching fraction B(B0s→τ+τ−)<6.8×10−3 at the 95% confidence level. If instead no contribution from B0s→τ+τ− decays is assumed, the limit is B(B0→τ+τ−)<2.1×10−3 at the 95% confidence level. These results correspond to the first direct limit on B(B0s→τ+τ−) and the world’s best limit on B(B0→τ+τ−)

The relationship between forgone health care and high school dropout:evidence from US adolescents

High school dropout is an important policy issue and its determinants are a longstanding interest of economics. However, very little is known on the roles of noncognitive traits in influencing school dropout decisions. We employ voluntary forgone health care as a proxy for the underlying noncognitive traits that may induce adolescents to dropout and estimate its effects on early school attrition. We exploit data from the US National Longitudinal Study of Adolescent to Adult Health (Add Health) and employ a series of flexible specifications with school fixed effects and cohort effects. Our models account for well-established determinants of dropout, including individual and parental characteristics, together with personality traits. Forgone health care consistently appears to be a statistically significant and substantial predictor of dropout among adolescents. We suggest that forgone health care could be used as a signaling device for policy makers targeting potential high school dropouts

The impact of public smoking bans on well-being externalities: evidence from a natural experiment

Recent studies on the effects of anti-smoking policies on subjective well-being present mixed results and focus mainly on smokers. We contribute to the literature by exploiting the policy experiment provided by the UK public smoking bans and evaluating the impact of smoking bans on the subjective well-being of smokers, non-smokers and couples of different types of smokers. We employ matching techniques combined with flexible difference-in-differences fixed effects panel data models on data from the British Household Panel Survey. We find that the UK public smoking bans appear to have a statistically significant short-term positive impact on the well-being of married individuals, especially among couples with dependent children. These effects appear to be substantial in size, robust to alternative specifications and may be driven by positive externalities due to parental altruism

Prospects for Detecting a Neutrino Magnetic Moment with a Tritium Source and Beta-beams

We compare the prospects for detecting a neutrino magnetic moment by the measurement of neutrinos from a tritium source, reactors and low-energy beta-beams. In all cases the neutrinos or antineutrinos are detected by scattering of electrons. We find that a large (20 MCurie) tritium source could improve the limit on the neutrino magnetic moment significantly, down to the level of a few $\times 10^{-12}$ while low-energy beta-beams with sufficiently rapid production of ions could improve the limits to the level of a few $\times 10^{-11}$. The latter would require ion production at the rate of at least $10^{15}$ s$^{-1}$.Comment: 6 pages, 3 figure