13,610 research outputs found
Moser-Trudinger inequality on conformal discs
We show that the Moser-Trudinger inequality holds in a conformal disc if and
only if the metric is bounded from above by the Hyperbolic metric. We also find
a necessary and sufficient condition for the Moser-Trudinger inequality to hold
in an unbounded subset of the two dimensional Euclidean space
Quantum channels from reflections on moving mirrors
Light reflection on a mirror can be thought as a simple physical effect.
However if this happens when the mirror moves a rich scenario opens up. Here we
aim at analyzing it from a quantum communication perspective. In particular, we
study the kind of quantum channel that arises from (Gaussian) light reflection
upon an accelerating mirror. Two competing mechanisms emerge in such a context,
namely photons production by the mirror's motion and {\blu interference between
modes}. As consequence we find out a quantum amplifier channel and quantum
lossy channel respectively below and above a threshold frequency (that depends
on parameters determining mirror's acceleration). Exactly at the threshold
frequency the channel behaves like a purely classical additive channel, while
it becomes purely erasure for large frequencies. In addition the time behavior
of the channel is analyzed by employing wave packets expansion of the light
field.Comment: 12 pages, 3 figure
Privacy of a lossy bosonic memory channel
We study the security of the information transmission between two honest
parties realized through a lossy bosonic memory channel when losses are
captured by a dishonest party. We then show that entangled inputs can enhance
the private information of such a channel, which however does never overcome
that of unentangled inputs in absence of memory.Comment: RevTex file, 4 pages, 2 figure
Integration of the VIMOS control system
The VIRMOS consortium of French and Italian Institutes (PI: O. Le Fevre,
co-PI: G. Vettolani) is manufacturing two wide field imaging multi-object
spectrographs for the European Southern Observatory Very Large Telescope (VLT),
with emphasis on the ability to carry over spectroscopic surveys of large
numbers of sources: the VIsible Multi-Object Spectrograph, VIMOS, and the Near
InfraRed Multi-Object Spectrograph, NIRMOS. There are 52 motors to be
controlled in parallel in the spectrograph, making VIMOS a complex machine to
be handled. This paper will focus on the description of the control system,
designed in the ESO VLT standard control concepts, and on some integration
issues and problem solving strategies.Comment: 3 pages, 3 figures, ICALEPCS 2001 Conference, PSN#TUBT00
Exact solution of the 1D Hubbard model in the atomic limit with inter-site magnetic coupling
In this paper we present for the first time the exact solution in the
narrow-band limit of the 1D extended Hubbard model with nearest-neighbour
spin-spin interactions described by an exchange constant J. An external
magnetic field h is also taken into account. This result has been obtained in
the framework of the Green's functions formalism, using the Composite Operator
Method. By means of this theoretical background, we have studied some relevant
features such as double occupancy, magnetization, spin-spin and charge-charge
correlation functions and derived a phase diagram for both ferro (J>0) and
anti-ferro (J<0) coupling in the limit of zero temperature. We also report a
study on density of states, specific heat, charge and spin susceptibilities. In
the limit of zero temperature, we show that the model exhibits a very rich
phase diagram characterized by different magnetic orders and by the coexistence
of charge and spin orderings at commensurate filling. Moreover, our analysis at
finite temperature of density of states and response functions shows the
presence of low-temperature charge and spin excitations near the phase
boundaries.Comment: 20 pages, 32 figure
Drug repurposing against COVID-19. focus on anticancer agents
The very limited time allowed to face the COVID-19 pandemic poses a pressing challenge to find proper therapeutic approaches. However, synthesis and full investigation from preclinical studies to phase III trials of new medications is a time-consuming procedure, and not viable in a global emergency, such as the one we are facing
Reconstructing the density operator by using generalized field quadratures
The Wigner function for one and two-mode quantum systems is explicitely
expressed in terms of the marginal distribution for the generic linearly
transformed quadratures. Then, also the density operator of those systems is
written in terms of the marginal distribution of these quadratures. Some
examples to apply this formalism, and a reduction to the usual optical homodyne
tomography are considered.Comment: 17 pages, Latex,accepted by Quantum and Semiclassical Optic
GANGLIOSIDE GM1 AS ADJUVANT FOR ORKAMBI® THERAPY TO RESTORE PLASMA MEMBRANE STABILITY AND FUNCTION OF F508DEL-CFTR
Cystic fibrosis (CF) is the most common, fatal genetic disease in the Caucasian population caused by loss of function mutations in gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is expressed at the apical surface of epithelial cells of different organs, such as: lungs, pancreas, gut, and testes. For this reason even if in CF the pulmonary manifestations are the most severe, CF is considered a multi-system disease, which affects several bodily districts.
The new challenge for the CF therapy is based on the development of small molecules able to rescue the function of the mutated CFTR. Many pharmacological agents have been designed to increase the surface level of mutated CFTR (correctors), as well as its plasma membrane (PM) activity (potentiators).
Recently, combined therapy that includes a corrector of the CFTR folding (lumacaftor or VX-809) and a potentiator of the channel activity (ivacaftor or VX-770) called Orkambi\uae, was approved for CF patients homozygous for the deletion of phenylalanine at position 508 (F508del), the most common CF-causing mutation. Unfortunately, clinical studies revealed that the effects of Orkambi\uae on lung function were modest, due to low stability of rescued F508del-CFTR at the PM level.
Indeed, many factors contribute to PM CFTR stability, including its compartmentalization in PM macromolecular complexes composed of phospholipids, sphingolipids, with particular regards for monosialoganglioside 1 (GM1), and scaffolding proteins such as ezrin and NHERF-1.
Interestingly, it has been proved that in bronchial epithelial cells the lack of CFTR in the cell PM, such as in the case of the patients carrying the mutation F508del, is associated with a decreased content of GM1. By performing photolabelling experiments, I demonstrated for the first time that GM1 and CFTR at PM level reside in the same microdomain, suggesting a direct interaction between them. Then I investigated on the potential effect of the exogenous administration of ganglioside GM1 on the PM stabilization and function of F508del-CFTR rescued by Orkambi\uae treatment. In particular, I proved that in CF bronchial epithelial cells GM1 antagonizes the negative effect of VX-770, increasing F508del-CFTR maturation and its channel activity by the recruitment of the scaffolding proteins NHERF-1 and ezrin.
Taken together the results obtained during my PhD project pointed out the role of GM1 as possible adjuvant to Orkambi\uae therapy to restore the function of F508del-CFTR
Sensitivity studies based on the EFT parametrization in the double differential cross section for the H →ZZ∗ →4l decay channel at LHC
After the Higgs boson discovery, great interest was given to the measurements of its properties and studies have been performed to test its nature and probe whether it is the Standard Model (SM) Higgs boson or not. In this scenario,
a set of pseudo-observables characterizing the properties of the Higgs decays are defined in generic extensions of the SM with no new particles below the Higgs mass. A phenomenological study is presented in the context of the Effective Field Theory (EFT) approach to the Higgs Physics. The expected sensitivity with the next LHC runs to the EFT parameters has been evaluated using the measurement of the double differential cross section for the H → ZZ∗ → 4l decay channel
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