Robust estimators for the fixed effects panel data model.

The presence of outlying observations in panel data can affect the classical estimates in a dramatic way. Nevertheless the common practice seems to disregard the problem. The aim of this work is to study robust regression techniques in the fixed effects linear panel data framework. Robustness of the procedures is investigated by means of breakdown point computations and simulation experiments. A distinction between outlying blocks and cells in a panel is made. To show the potential of robust panel data methods an empirical example on the response of the private sector behavior to fiscal policy is presented.Breakdown point; Data; Effects; Estimator; Fixed effects model; Framework; Linear regression; Methods; Model; Panel data; Policy; Private sector; Regression; Robust regression; Robustness; Simulation; Studies;

On the norms of quaternionic harmonic projection operators

As a consequence of integral bounds for three classes of quaternionic spherical harmon-ics, we prove some bounds from below for the (Lp,L2) norm of quaternionic harmonic projectors, for p between 1 and 2

A family of sharp inequalities on real spheres

We prove a family of sharp multilinear integral inequalities on real spheres involving functions that possess some symmetries that can be described by annihilation by certain sets of vector fields. The Lebesgue exponents involved are seen to be related to the combinatorics of such sets of vector fields. Moreover, we derive some Euclidean Brascamp–Lieb inequalities localized to a ball of radius R, with a blow-up factor of type R^δ, where the exponent δ is related to the aforementioned Lebesgue exponents, and prove that in some cases δ is optimal

Teleportation of an atomic ensemble quantum state

We propose a protocol to achieve high fidelity quantum state teleportation of a macroscopic atomic ensemble using a pair of quantum-correlated atomic ensembles. We show how to prepare this pair of ensembles using quasiperfect quantum state transfer processes between light and atoms. Our protocol relies on optical joint measurements of the atomic ensemble states and magnetic feedback reconstruction

Single photons emitted by nano-crystals optically trapped in a deep parabolic mirror

We investigate the emission of single photons from CdSe/CdS dot-in-rods which are optically trapped in the focus of a deep parabolic mirror. Thanks to this mirror, we are able to image almost the full 4$\pi$ emission pattern of nanometer-sized elementary dipoles and verify the alignment of the rods within the optical trap. From the motional dynamics of the emitters in the trap we infer that the single-photon emission occurs from clusters comprising several emitters. We demonstrate the optical trapping of rod-shaped quantum emitters in a configuration suitable for efficiently coupling an ensemble of linear dipoles with the electromagnetic field in free space.Comment: updated version after review, including supplementary material as appendi

Faecal Calprotectin and a Twenty-Four-Parameter Questionnaire in Autistic Children with Gastrointestinal Symptoms

This study investigated potential correlation between the inflammatory marker, Calprotectin, and a S.O.S questionnaire from forty-nine Autistic children. Symptom and behavioral questionnaires were completed contemporaneously with stool sample collection. Mixed Model data analysis showed strong correlation between some questionnaire parameters and Calprotectin. ‘Need for a fixed routine’ was highly significantly correlated with Calprotectin (\u1d45d<0.00009) with Multivariate Coefficient of 3.227, whilst paradoxically ‘constipation’ indicated significant change (\u1d45d<0.02) with negative Multivariate Coefficient (-1.584). The negative ‘constipation’ appears to associate with the positive ‘need for a fixed routine’ indicating possibility of reciprocal, independent prediction of gastrointestinal inflammation. Results suggest that ‘need for a fixed routine’ and ‘constipation’ be included in a screening questionnaire as independent predictors of bowel dysfunction in these children