535 research outputs found
A compact light readout system for longitudinally segmented shashlik calorimeters
The longitudinal segmentation of shashlik calorimeters is challenged by dead
zones and non-uniformities introduced by the light collection and readout
system. This limitation can be overcome by direct fiber-photosensor coupling,
avoiding routing and bundling of the wavelength shifter fibers and embedding
ultra-compact photosensors (SiPMs) in the bulk of the calorimeter. We present
the first experimental test of this readout scheme performed at the CERN PS-T9
beamline in 2015 with negative particles in the 1-5~GeV energy range. In this
paper, we demonstrate that the scheme does not compromise the energy resolution
and linearity compared with standard light collection and readout systems. In
addition, we study the performance of the calorimeter for partially contained
charged hadrons to assess the separation capability and the response of
the photosensors to direct ionization.Comment: To appear in Nuclear Instruments and Methods in Physics Research,
Generic Modal Cut Elimination Applied to Conditional Logics
We develop a general criterion for cut elimination in sequent calculi for
propositional modal logics, which rests on absorption of cut, contraction,
weakening and inversion by the purely modal part of the rule system. Our
criterion applies also to a wide variety of logics outside the realm of normal
modal logic. We give extensive example instantiations of our framework to
various conditional logics. For these, we obtain fully internalised calculi
which are substantially simpler than those known in the literature, along with
leaner proofs of cut elimination and complexity. In one case, conditional logic
with modus ponens and conditional excluded middle, cut elimination and
complexity were explicitly stated as open in the literature
Updates in Rhea - an expert curated resource of biochemical reactions.
Rhea (http://www.rhea-db.org) is a comprehensive and non-redundant resource of expert-curated biochemical reactions designed for the functional annotation of enzymes and the description of metabolic networks. Rhea describes enzyme-catalyzed reactions covering the IUBMB Enzyme Nomenclature list as well as additional reactions, including spontaneously occurring reactions, using entities from the ChEBI (Chemical Entities of Biological Interest) ontology of small molecules. Here we describe developments in Rhea since our last report in the database issue of Nucleic Acids Research. These include the first implementation of a simple hierarchical classification of reactions, improved coverage of the IUBMB Enzyme Nomenclature list and additional reactions through continuing expert curation, and the development of a new website to serve this improved dataset
A new approach for the treatment of CLL using chlorambucil/hydroxychloroquine-loaded anti-CD20 nanoparticles
Current approaches for the treatment of chronic lymphocytic leukemia (CLL) have greatly improved the prognosis for survival, but some patients remain refractive to these therapeutic regimens. Hence, in addition to reducing the long-term sideeffects of therapeutics for all leukemia patients, there is an urgent need for novel therapeutic strategies for difficult-to-treat leukemia cases. Due to the cytotoxicity of drugs, the major challenge currently is to deliver the therapeutic agents to neoplastic cells while preserving the viability of non-malignant cells. In this study, we propose a therapeutic approach in which high doses of hydroxychloroquine and chlorambucil were loaded into biodegradable polymeric nanoparticles coated with an anti-CD20 antibody.We first demonstrated the ability of the nanoparticles to target and internalize in tumor B-cells. Moreover, these nanoparticles could kill not only p53-mutated/deleted leukemia cells expressing a low amount of CD20, but also circulating primary cells isolated from chronic lymphocytic leukemia patients. The safety of these nanoparticles was also demonstrated in healthy mice, and their therapeutic effects were shown in a new model of aggressive leukemia. These results showed that anti-CD20 nanoparticles containing hydroxychloroquine and chlorambucil can be effective in controlling aggressive leukemia and provided a rationale for adopting this approach for the treatment of other B-cell disorders. [Figure not available: see fulltext.
Prospect for Charge Current Neutrino Interactions Measurements at the CERN-PS
Tensions in several phenomenological models grew with experimental results on
neutrino/antineutrino oscillations at Short-Baseline (SBL) and with the recent,
carefully recomputed, antineutrino fluxes from nuclear reactors. At a
refurbished SBL CERN-PS facility an experiment aimed to address the open issues
has been proposed [1], based on the technology of imaging in ultra-pure
cryogenic Liquid Argon (LAr). Motivated by this scenario a detailed study of
the physics case was performed. We tackled specific physics models and we
optimized the neutrino beam through a full simulation. Experimental aspects not
fully covered by the LAr detection, i.e. the measurements of the lepton charge
on event-by-event basis and their energy over a wide range, were also
investigated. Indeed the muon leptons from Charged Current (CC) (anti-)neutrino
interactions play an important role in disentangling different phenomenological
scenarios provided their charge state is determined. Also, the study of muon
appearance/disappearance can benefit of the large statistics of CC muon events
from the primary neutrino beam. Results of our study are reported in detail in
this proposal. We aim to design, construct and install two Spectrometers at
"NEAR" and "FAR" sites of the SBL CERN-PS, compatible with the already proposed
LAr detectors. Profiting of the large mass of the two Spectrometers their
stand-alone performances have also been exploited.Comment: 70 pages, 38 figures. Proposal submitted to SPS-C, CER
Prospects for the measurement of muon-neutrino disappearance at the FNAL-Booster
Neutrino physics is nowadays receiving more and more attention as a possible
source of information for the long-standing problem of new physics beyond the
Standard Model. The recent measurement of the mixing angle in the
standard mixing oscillation scenario encourages us to pursue the still missing
results on leptonic CP violation and absolute neutrino masses. However,
puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE
Collaboration has been setup to undertake conclusive experiments to clarify the
muon-neutrino disappearance measurements at small , which will be able to
put severe constraints to models with more than the three-standard neutrinos,
or even to robustly measure the presence of a new kind of neutrino oscillation
for the first time. To this aim the use of the current FNAL-Booster neutrino
beam for a Short-Baseline experiment has been carefully evaluated. This
proposal refers to the use of magnetic spectrometers at two different sites,
Near and Far. Their positions have been extensively studied, together with the
possible performances of two OPERA-like spectrometers. The proposal is
constrained by availability of existing hardware and a time-schedule compatible
with the CERN project for a new more performant neutrino beam, which will
nicely extend the physics results achievable at the Booster. The possible FNAL
experiment will allow to clarify the current disappearance tension
with appearance and disappearance at the eV mass scale. Instead, a new
CERN neutrino beam would allow a further span in the parameter space together
with a refined control of systematics and, more relevant, the measurement of
the antineutrino sector, by upgrading the spectrometer with detectors currently
under R&D study.Comment: 76 pages, 52 figure
Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network
We have studied the performance of a new algorithm for electron/pion
separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion
films. The software for separation consists of two parts: a shower
reconstruction algorithm and a Neural Network that assigns to each
reconstructed shower the probability to be an electron or a pion. The
performance has been studied for the ECC of the OPERA experiment [1].
The separation algorithm has been optimized by using a detailed Monte
Carlo simulation of the ECC and tested on real data taken at CERN (pion beams)
and at DESY (electron beams). The algorithm allows to achieve a 90% electron
identification efficiency with a pion misidentification smaller than 1% for
energies higher than 2 GeV
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