Implementation of ROSA radio occultation data handling into EUMETSAT and GRAS SAF processing

Within this contribution, outcomes from a GRAS - SAF Visiting Scientist activity focused on the analysis of ROSA data quality for their use in operational weather forecasting will be described and main results will be shown. The ROSA Radio Occultation instrument has been developed by Thales-Alenia-Space, Italy and was funded by the Italian Space Agency (ASI). Such instrument is actually flying on-board three opportunity missions: the Indian OCEANSAT-2, the Argentinean SAC-D and the Indian-French MEGATROPIQUES. Focus of this Visiting Scientist activity has primarily been the analysis of ROSA data from OCEANSAT-2.This activity was divided into two parts. In the first one, performed at EUMETSAT, ROSA data processing was implemented into the EUMETSAT YAROS processor. The required updates into such processing package were implemented in order to make it able to properly manage also ROSA raw observations. It has to be noted that this processor is the baseline for the operational next generation EUMETSAT Radio Occultation ground segment: any changes performed in the framework of YAROS can easily be transferred to the operational ground segment. The YAROS - EUMETSAT processor was then updated and adapted to work with the ROSA raw data, tracking frequencies and instrument database. Adaptation to open loop data, navigation bits acquisition and potentially ionospheric measurement will be performed in the next future. NetCDF-4 YAROS output files are phases, amplitudes, bending angles over impact parameter, along with all other required data. Robust bias and standard deviation of bending angles to ECMWF collocated data were the statistical indicators generated to evaluate the quality of the ROSA observations. The second part of the activity was the adaptation of the GRAS-SAF ROPP (Radio Occultation Processing Package) processor for ROSA data processing. This second part was performed at Danish Meteorological Institute and has been focused on bending angles, refractivity and higher level product generation and validation against ECMWF and co-located occultation profiles. For the first time, one month of ROSA data have been deeply analyzed by a state-of-the-art Radio Occultation processing software and results will be described in the framework of this contributio

A Quantum Monte Carlo algorithm for non-local corrections to the Dynamical Mean-Field Approximation

We present the algorithmic details of the dynamical cluster approximation (DCA), with a quantum Monte Carlo (QMC) method used to solve the effective cluster problem. The DCA is a fully-causal approach which systematically restores non-local correlations to the dynamical mean field approximation (DMFA) while preserving the lattice symmetries. The DCA becomes exact for an infinite cluster size, while reducing to the DMFA for a cluster size of unity. We present a generalization of the Hirsch-Fye QMC algorithm for the solution of the embedded cluster problem. We use the two-dimensional Hubbard model to illustrate the performance of the DCA technique. At half-filling, we show that the DCA drives the spurious finite-temperature antiferromagnetic transition found in the DMFA slowly towards zero temperature as the cluster size increases, in conformity with the Mermin-Wagner theorem. Moreover, we find that there is a finite temperature metal to insulator transition which persists into the weak-coupling regime. This suggests that the magnetism of the model is Heisenberg like for all non-zero interactions. Away from half-filling, we find that the sign problem that arises in QMC simulations is significantly less severe in the context of DCA. Hence, we were able to obtain good statistics for small clusters. For these clusters, the DCA results show evidence of non-Fermi liquid behavior and superconductivity near half-filling.Comment: 25 pages, 15 figure

Pathophysiology of L-dopa-induced motor and non-motor complications in Parkinson's disease

Involuntary movements, or dyskinesia, represent a debilitating complication of levodopa (L-dopa) therapy for Parkinson's disease (PD). L-dopa-induced dyskinesia (LID) are ultimately experienced by the vast majority of patients. In addition, psychiatric conditions often manifested as compulsive behaviours, are emerging as a serious problem in the management of L-dopa therapy. The present review attempts to provide an overview of our current understanding of dyskinesia and other L-dopa-induced dysfunctions, a field that dramatically evolved in the past twenty years. In view of the extensive literature on LID, there appeared a critical need to re-frame the concepts, to highlight the most suitable models, to review the central nervous system (CNS) circuitry that may be involved, and to propose a pathophysiological framework was timely and necessary. An updated review to clarify our understanding of LID and other L-dopa-related side effects was therefore timely and necessary. This review should help in the development of novel therapeutic strategies aimed at preventing the generation of dyskinetic symptoms

Mitochondrial division inhibitor-1 is neuroprotective in the A53T-α-synuclein rat model of Parkinson’s disease

Alpha-synuclein (α-syn) is involved in both familial and sporadic Parkinson’s disease (PD). One of the proposed pathogenic mechanisms of α-syn mutations is mitochondrial dysfunction. However, it is not entirely clear the impact of impaired mitochondrial dynamics induced by α-syn on neurodegeneration and whether targeting this pathway has therapeutic potential. In this study we evaluated whether inhibition of mitochondrial fission is neuroprotective against α-syn overexpression in vivo. To accomplish this goal, we overexpressed human A53T-α- synuclein (hA53T-α-syn) in the rat nigrostriatal pathway, with or without treatment using the small molecule Mitochondrial Division Inhibitor-1 (mdivi-1), a putative inhibitor of the mitochondrial fission Dynamin-Related Protein-1 (Drp1). We show here that mdivi-1 reduced neurodegeneration, α-syn aggregates and normalized motor function. Mechanistically, mdivi-1 reduced mitochondrial fragmentation, mitochondrial dysfunction and oxidative stress. These in vivo results support the negative role of mutant α-syn in mitochondrial function and indicate that mdivi-1 has a high therapeutic potential for PD

Understanding the variability of clear-sky outgoing long-wave radiation based on ship-based temperature and water vapour measurements

High-resolution radiative transfer model calculations with the Atmospheric Radiative Transfer Simulator (ARTS) were used to simulate the clear-sky outgoing long-wave radiative flux (OLR) at the top of the atmosphere. The unique set of radiosonde data collected by the research vessel Polarstern of the Alfred Wegener Institute for Polar and Marine Research during 27 expeditions in the years 1982 to 2003 was used to investigate the sources of clear-sky OLR variability for ocean areas in different climate zones and seasons. For this dataset, tropospheric temperature variations contribute approximately 33 W m(-2) OLR variability. tropospheric relative humidity variations 8.5 W m(-2), and vertical structure 2.3-3.4 W m(-2). Of these, 0.3-1.0 W m(-2) are due to structures on a vertical scale smaller than 4 km, which cannot be resolved by conventional remote-sensing instruments. It was also found that the poor absolute accuracy of current humidity data in the upper troposphere, approximately 40% relative error in relative humidity, leads to a significant uncertainty in OLR of about 3.8 W m(-2) (for a midlatitude summer atmosphere), which should be put in the context of the double CO2 effect of only 2.6 W m(-2) (for the same atmosphere).Validerad; 2006; 20070427 (pafi)</p