3,559 research outputs found
Improved intracellular processing of protein variants as a personalized therapeutic approach for Haemophilia
No full textSevere bleeding disorders such as Haemophilia B are mainly caused by missense mutations that may affect protein folding, thus leading to the production of structurally-altered proteins associated with low or very low circulating levels. The research activity was aimed at characterizing the mechanism underlying the defective intracellular biosynthesis (misfolding), premature degradation and/or stress of the endoplasmic reticulum in cellular models of sever Haemophilia B and to evaluate the effects of small molecules or drugs acting as chemical/pharmacological chaperones in restoring the molecular defect. Reference: Pignani S, Todaro A, Ferrarese M, Marchi S, Lombardi S, Balestra D, Pinton P, Bernardi F, Pinotti M, Branchini A. The chaperone-like sodium phenylbutyrate improves factor IX intracellular trafficking and activity impaired by the frequent p.R294Q mutation. J Thromb Haemost. 2018 Oct;16(10):2035-2043
Neutron irradiation test on ATLAS MDT chambers
No full textThe Monitored Drift Tubes (MDT) chambers of the ATLAS muon spectrometer are crucial for the identification of high-momentum final-state muons, which represent very promising and robust signatures of physics at the LHC. They will operate in a high rate and high background environment and therefore their performances should not significantly degrade for the whole ATLAS data taking. The maximum expected total flux, mainly consisting of neutrons and photons in the MeV range, is of the order of 5 kHz/cm(2) for the barrel MDTs, while at SLHC, with machine working at higher luminosity, fluxes can be 10 times higher. To test detector robustness, a MDT test chamber was exposed to intensive neutron irradiation at the TAPIRO ENEA-Casaccia Research Center facility
Neutron intensive irradiation test on ATLAS MDT chambers at TAPIRO nuclear reactor
No full textThe Monitored Drift Tubes (MDT) chambers are the tracking device for the ATLAS muon spectrometer. They will have to cope with a high rate and high background environment; for this reason, possible aging effects must be taken into account in the choice of the operating point. Moreover, an upgrade of LHC to 10 times higher luminosity is also foreseen. To test detector robustness, a MDT test chamber was exposed to intensive neutron irradiation at the TAPIRO ENEA-Casaccia Research Center
ATLAS MDT chamber behaviour after neutron irradiation and in a high rate background
No full textMany of the physics processes of interest at the Large Hadron Collider (LHC) will involve muon production in the final state. The Monitored Drift Tube (MDT) chambers, the precision tracking elements of the ATLAS muon spectrometer, are the main tools for the muon identification and measurement. They will operate in the harsh LHC background environment, mainly due to low energy photons and neutrons which will dominate the counting rate in most areas of the spectrometer, where an overall maximum counting rate of 500 Hz/cm(2) is expected. The upgrade to Super-LHC will involve fluxes ten times higher. To study the behaviour of MDT chambers under massive neutron irradiation at the level of Super-LHC, a test was performed at the "Tapiro" Neutron Facility of the ENEA "La Casaccia" Research Cente
The cluster distribution as a test of dark matter models - III. The cluster velocity field
No full textWe study the large-scale velocity fields traced by galaxy clusters in numerical simulations of a box of side 960 h(-1) h(-1), and compare them with available data on real clusters. In order to test the reliability of the simulations, which are based on an optimized version of the Zel'dovich approximation, we compare their cluster velocities with those of 'exact' N-body simulations, and find a remarkable agreement between the two according to a variety of statistical tests. We analyse cold dark matter (CDM) models with density parameter in the range 0.2 less than or equal to Ohm(0) less than or equal to 1, both with and without the cosmological constant term to provide a flat geometry. We also simulate a cold+hot dark matter (CHDM) model, with 30 per cent provided by the hot component. Comparison with real data is performed by applying tests based on the cumulative velocity frequency distribution (CVFD) and bulk flow statistics. For the CVFD, we use observational velocity data from different authors, and find that results based on different data sets are contradictory. In particular, the recent infrared Tully-Fisher (IRTF) data of Giovanelli yield smaller velocities with smaller errors than both the IRTF and D-n-sigma data of Hudson. It turns out that the Giovanelli data are only only consistent with the open Ohm(0) = 0.4 and the flat Omega(0) = 0.2 models, while the Hudson data, though less discriminatory because of their larger errors, appear to exclude open models with Ohm(0) less than or equal to 0.4 and hat models with Ohm(0) = 0.2. This latter conclusion also holds if one pools all the data into a single sample regardless of the systematic differences in the two different sources. Furthermore, CVFD and bulk flow analyses of the Branchini et al. reconstructed velocity data again disfavour precisely those models accepted on the grounds of Giovanelli's sample. Finally, we confirm that the Lauer & Postman reported bulk flow determination would be a rare event in the cosmological models we have analysed
BAO reconstruction: a swift numerical action method for massive spectroscopic surveys
No full textInternational audienceA new fully non-linear reconstruction algorithm for the accurate recovery of the baryonic acoustic oscillations (BAO) scale in two-point correlation functions is proposed, based on the least action principle and extending the Fast Action Minimisation method by Nusser & Branchini (2000). Especially designed for massive spectroscopic surveys, it is tested on dark matter halo catalogues extracted from the deus-fur Lambda cold dark matter simulation (Reverdy et al. 2015) to trace the trajectories of up to || haloes backward in time, well beyond the first-order Lagrangian approximation. The new algorithm successfully recovers the BAO feature in real and redshift space in both the monopole and the anisotropic two-point correlation function, also for anomalous samples showing misplaced or absent signature of BAO. In redshift space, the non-linear displacement parameter Σ_NL is reduced from || Mpc at redshift || = 0 to || Mpc at || ≃ 37 after reconstruction. A comparison with the first-order Lagrangian reconstruction is presented, showing that these techniques outperform the linear approximation in recovering an unbiased measurement of the acoustic scale
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