7,128 research outputs found
Novel diagnostic for precise measurement of the modulation frequency of Seeded Self-Modulation via Coherent Transition Radiation in AWAKE
We present the set-up and test-measurements of a waveguide-integrated
heterodyne diagnostic for coherent transition radiation (CTR) in the AWAKE
experiment. The goal of the proof-of-principle experiment AWAKE is to
accelerate a witness electron bunch in the plasma wakefield of a long proton
bunch that is transformed by Seeded Self-Modulation (SSM) into a train of
proton micro-bunches. The CTR pulse of the self-modulated proton bunch is
expected to have a frequency in the range of 90-300 GHz and a duration of
300-700 ps. The diagnostic set-up, which is designed to precisely measure the
frequency and shape of this CTR-pulse, consists of two waveguide-integrated
receivers that are able to measure simultaneously. They cover a significant
fraction of the available plasma frequencies: the bandwidth 90-140 GHz as well
as the bandwidth 255-270 GHz or 170-260 GHz in an earlier or a latter version
of the set-up, respectively. The two mixers convert the CTR into a signal in
the range of 5-20 GHz that is measured on a fast oscilloscope, with a high
spectral resolution of 1-3 GHz dominated by the pulse length. In this
contribution, we will describe the measurement principle, the experimental
set-up and a benchmarking of the diagnostic in AWAKE.Comment: Conference proceedings to 3rd European Advanced Accelerator Concepts
Worksho
Entanglement in thermal equilibrium states
We revisist the issue of entanglement of thermal equilibrium states in
composite quantum systems. The possible scenarios are exemplified in bipartite
qubit/qubit and qubit/qutrit systems.Comment: 4 figure
NICU Infants & SNHL: Experience of a western Sicily tertiary care centre
Introduction: The variability of symptoms and signs caused by central nervous system (CNS) lesions make multiple sclerosis difficult to recognize,Introduction: This study adds the evaluation of the independent etiologic factors that may play a role in the development of SNHL in a NICU population. We compared neonatal intensive care unit NICU infants with sensorineural hearing loss SNHL to age and gender matched normal hearing NICU controls. Materials and methods: 284 consecutive NICU infants positive to the presence of risk indicators associated with permanent congenital, delayed-onset, or progressive hearing loss underwent to global audiological assessment. The following risk factors were researched, making a distinction between prenatal and perinatal risk factors: in the first group, family history of permanent childhood hearing impairment, consanguinity, pregnant maternal infection and drugs exposition during pregnancy; in the second group, premature birth, respiratory distress, hyperbilirubinemia requiring exchange tranfusion, very low birth weight, cranio-facial abnormality, perinatal infections, ototoxic drugs administration, acidosis, hyponatremia, head trauma. Results: The analysis of the auditory deficit for infants according to numbers of risk factors showed mean values of: 78 + 28.08 dB nHL for infants positive to two risk factors; 75.71 + 30.30 dB nHL in cases positive to three risk factors; 96.66 + 34.46 dB nHL for four risk factors and 85 + 35 dB nHL in case of >5 risk factors. Conclusion: NICU infants have greater chances of developing SNHL, because of the presence of multiple risk factors; in fact, as the number of coexisting risk factors increases, the prevalence rate of SNHL also increases (r=0.81)
Revealing quantum statistics with a pair of distant atoms
Quantum statistics have a profound impact on the properties of systems
composed of identical particles. In this Letter, we demonstrate that the
quantum statistics of a pair of identical massive particles can be probed by a
direct measurement of the exchange symmetry of their wave function even in
conditions where the particles always remain spatially well separated and thus
the exchange contribution to their interaction energy is negligible. We present
two protocols revealing the bosonic or fermionic nature of a pair of particles
and discuss possible implementations with a pair of trapped atoms or ions.Comment: 4+13 pages, v2 corresponds to the version published by PR
Singular kernels, multiscale decomposition of microstructure, and dislocation models
We consider a model for dislocations in crystals introduced by Koslowski,
Cuiti\~no and Ortiz, which includes elastic interactions via a singular kernel
behaving as the norm of the slip. We obtain a sharp-interface limit
of the model within the framework of -convergence. From an analytical
point of view, our functional is a vector-valued generalization of the one
studied by Alberti, Bouchitt\'e and Seppecher to which their rearrangement
argument no longer applies. Instead we show that the microstructure must be
approximately one-dimensional on most length scales and exploit this property
to derive a sharp lower bound
A simple abstraction of arrays and maps by program translation
We present an approach for the static analysis of programs handling arrays,
with a Galois connection between the semantics of the array program and
semantics of purely scalar operations. The simplest way to implement it is by
automatic, syntactic transformation of the array program into a scalar program
followed analysis of the scalar program with any static analysis technique
(abstract interpretation, acceleration, predicate abstraction,.. .). The
scalars invariants thus obtained are translated back onto the original program
as universally quantified array invariants. We illustrate our approach on a
variety of examples, leading to the " Dutch flag " algorithm
Fidelity and Concurrence of conjugated states
We prove some new properties of fidelity (transition probability) and
concurrence, the latter defined by straightforward extension of Wootters
notation. Choose a conjugation and consider the dependence of fidelity or of
concurrence on conjugated pairs of density operators. These functions turn out
to be concave or convex roofs. Optimal decompositions are constructed. Some
applications to two- and tripartite systems illustrate the general theorem.Comment: 10 pages, RevTex, Correction: Enlarged, reorganized version. More
explanation
Antinuclear antibodies (ANA) in chronic hepatitis C virus infection: correlates of positivity and clinical relevance.
We examined correlates of antinuclear antibody (ANA) positivity (ANA+) in individuals with chronic hepatitis C virus (HCV) infection and the effect of positivity on clinical outcome of HCV. Pretreatment sera from 645 patients from three centres in Sweden (n = 225), the UK (n = 207) and Italy (n = 213) were evaluated by indirect immunofluorescence on Hep-2 cells for ANA pattern and titre by a single laboratory. Liver biopsies were all scored by one pathologist. A total of 258 patients were subsequently treated with interferon monotherapy. There was a significant difference in the prevalence of ANA (1:40) by geographic location: Lund 4.4%, London 8.7%, Padova 10.3% [odds ratio (OR) = 0.66; 95% CI: 0.46-0.94; P = 0.023]. Duration of HCV infection, age at infection, current age, route of infection, viral genotype, alcohol consumption, fibrosis stage and inflammatory score were not correlated with ANA+ or ANA pattern. Female gender was correlated with ANA+ and this association persisted in multivariable analyses (OR = 3.0; P = 0.002). Increased plasma cells were observed in the liver biopsies of ANA-positive individuals compared with ANA-negative individuals, while a trend towards decreased lymphoid aggregates was observed [hazard ratio (HR) = 9.0, P = 0.037; HR = 0.291, P = 0.118, respectively]. No correlations were observed between ANA positivity and nonresponse to therapy (OR = 1.4; P = 0.513), although ANA+ was correlated with faster rates of liver fibrosis, this was not statistically significant (OR = 1.8; P = 0.1452). Low titre ANA+ should not be a contraindication for interferon treatment. Our observation of increased plasma cells in ANA+ biopsies might suggest B-cell polyclonal activity with a secondary clinical manifestation of increased serum immunoglobulins
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