302 research outputs found
Entropy production in Gaussian bosonic transformations using the replica method: application to quantum optics
In spite of their simple description in terms of rotations or symplectic
transformations in phase space, quadratic Hamiltonians such as those modeling
the most common Gaussian operations on bosonic modes remain poorly understood
in terms of entropy production. For instance, determining the von Neumann
entropy produced by a Bogoliubov transformation is notably a hard problem, with
generally no known analytical solution. Here, we overcome this difficulty by
using the replica method, a tool borrowed from statistical physics and quantum
field theory. We exhibit a first application of this method to the field of
quantum optics, where it enables accessing entropies in a two-mode squeezer or
optical parametric amplifier. As an illustration, we determine the entropy
generated by amplifying a binary superposition of the vacuum and an arbitrary
Fock state, which yields a surprisingly simple, yet unknown analytical
expression
Editorial of the 1st International Cross-Industry Safety Conference proceedings
The Amsterdam University of Applied Sciences was proud to organize the 1 st International Cross-industry Safety Conference (ICSC) dedicate d to both practical and theoretical aspects of safety. The conference functioned as a plat form to disseminate and share knowledge and experience about safety within and between industry and academia. The conference featured keynote speeches by Neville Stanton (Professor of Human Factors in Transport at the University of Southampton, UK), Johan Svenningsson (CEO Sydkraft Nuclear Power AB & Country Chairman Uniper, Sweden), David Lindley (Aviation Engineering and Safety Consultant, UK), and Bart Poolman (Lead QASHE Advisor for Heerema Marine Contractors, NL)..
Zig Zag symmetry in AdS/CFT duality
The validity of the Bianchi identity, which is intimately connected with the
zig zag symmetry, is established, for piecewise continuous contours, in the
context of Polakov's gauge field-string connection in the large 'tHooft
coupling limit, according to which the chromoelectric `string' propagates in
five dimensions with its ends attached on a Wilson loop in four dimensions. An
explicit check in the wavy line approximation is presented.Comment: 24 pages version to appear in EPJ
Non-perturbative quenched propagator beyond the infrared approximation
A new approach to the quenched propagator in QED beyond the IR limit is
proposed. The method is based on evolution equations in the proper time.Comment: 13 pages, 1 figure; Misprint on reference correcte
Worldline Casting of the Stochastic Vacuum Model and Non-Perturbative Properties of QCD: General Formalism and Applications
The Stochastic Vacuum Model for QCD, proposed by Dosch and Simonov, is fused
with a Worldline casting of the underlying theory, i.e. QCD. Important,
non-perturbative features of the model are studied. In particular,
contributions associated with the spin-field interaction are calculated and
both the validity of the loop equations and of the Bianchi identity are
explicitly demonstrated. As an application, a simulated meson-meson scattering
problem is studied in the Regge kinematical regime. The process is modeled in
terms of the "helicoidal" Wilson contour along the lines introduced by Janik
and Peschanski in a related study based on a AdS/CFT-type approach. Working
strictly in the framework of the Stochastic Vacuum Model and in a semiclassical
approximation scheme the Regge behavior for the Scattering amplitude is
demonstrated. Going beyond this approximation, the contribution resulting from
boundary fluctuation of the Wilson loop contour is also estimated.Comment: 37 pages, 1 figure. Final version to appear in Phys.Rev.
Evolving text classification rules with genetic programming
We describe a novel method for using genetic programming to create compact classification rules using combinations of N-grams (character strings). Genetic programs acquire fitness by producing rules that are effective classifiers in terms of precision and recall when evaluated against a set of training documents. We describe a set of functions and terminals and provide results from a classification task using the Reuters 21578 dataset. We also suggest that the rules may have a number of other uses beyond classification and provide a basis for text mining applications
Worldline Approach to Forward and Fixed Angle fermion-fermion Scattering in Yang-Mills Theories at High Energies
Worldline techniques are employed to study the general behaviour of the
fermion-fermion collision amplitude at very high energies in a non-abelian
gauge field theory for the forward and fixed angle scattering cases. A central
objective of this work is to demonstrate the simplicity by which the worldline
methodology isolates that sector of the full theory which carries the soft
physics, relevant to each process. Anomalous dimensions pertaining to a given
soft sector are identified and subseuently used to facilitate the
renormalization group running of the respective four point functions. Gluon
reggeization is achieved for forward, while Sudakov suppression is established
for fixed angle scattering.Comment: 28 pages, 10 figures in three file
Anyons in 1+1 Dimensions
The possibility of excitations with fractional spin and statististics in
dimensions is explored. The configuration space of a two-particle system
is the half-line. This makes the Hamiltonian self-adjoint for a family of
boundary conditions parametrized by one real number . The limit ) reproduces the propagator of non-relativistic
particles whose wavefunctions are even (odd) under particle exchange. A
relativistic ansatz is also proposed which reproduces the correct Polyakov spin
factor for the spinning particle in dimensions. These checks support
validity of the interpretation of as a parameter related to the
``spin'' that interpolates continuously between bosons () and
fermions (). Our approach can thus be useful for obtaining the
propagator for one-dimensional anyons.Comment: 13p. latex (Revtex), no figures
2OACTIVATION OF T CELLS UPON TREATMENT WITH BISPECIFIC ANTIBODIES CORRELATES WITH THE EXPRESSION OF CO-INHIBITORY RECEPTORS ON TUMOR-INFILTRATING LYMPHOCYTES IN HUMAN LUNG CANCER
Introduction: T cell bispecific antibodies (TCB) are designed to recruit and simultaneously activate T cells against target cells such as tumor cells expressing a particular surface antigen. However, it is currently unknown how immuno-modulatory mechanisms active in the tumor microenvironment such as the expression of T cell co-inhibitory receptors may influence the therapeutic effect of TCBs. Methods: We performed a comprehensive phenotypic analysis of tumor infiltrating immune cells from lung carcinoma digests by multicolour flow cytometry. In particular, expression of T cell co-inhibitory and -stimulatory receptors was analyzed. Tumor digests were treated with catumaxomab, a TCB directed against CD3 and EpCAM. T cell activation and effector functions were assessed upon exposure to catumaxomab. Results: CD8+ T cells in lung carcinoma showed a broad heterogeneity in expression of the T cell co-inhibitory receptors PD-1, Tim-3, CTLA-4, Lag-3 and BTLA. Tumor stage and nodal status correlated with number and intensity of expressed receptors. Upon exposure to catumaxomab, a considerable heterogeneity in T cell activation among different tumors was observed. Of note, T cells expressing high levels and multiple co-inhibitory receptors were more impaired in their activation and effector functions after treatment with catumaxomab indicating a higher level of exhaustion. In a further analysis of CD8+ TIL subsets we found that BTLA+ T cells expressed more additional inhibitory receptors than all other subsets, namely PD-1, Tim-3, CTLA-4 and Lag-3, whereas only a small part of PD-1+ T cells expressed another receptor. Tim-3+ T cells usually co-expressed PD-1, but multiple receptors were found only on a low number of cells. Conclusion: In summary, our data suggest that the activity of TCBs is largely affected by the expression of T cell co-inhibitory receptors on tumor-infiltrating immune cells. Furthermore, these data provide a clinical rationale for combining bispecific antibodies with compounds which antagonize T cell exhaustion. Disclosure: D. Thommen, J. Schreiner, P. Herzig, P. Mueller and A. Zippelius: received research funding from Roche Glycart; V. Karanikas: is employed by Roche Glycart. All other authors have declared no conflicts of interes
Cytolytic T-cell response against Epstein-Barr virus in lung cancer patients and healthy subjects
<p>Abstract</p> <p>Background</p> <p>This study aimed to examine whether EBV seropositive patients with lung cancer have an altered virus-specific CTL response, as compared to age-matched healthy controls and whether any variation in this response could be attributed to senescence.</p> <p>Methods</p> <p>Peripheral blood mononuclear cells from lung cancer patients, age-matched and younger healthy individuals were used to measure EBV-specific CTLs after in vitro amplification with the GLCTLVAML and RYSIFFDYM peptides followed by HLA-multimer staining.</p> <p>Results</p> <p>Lung cancer patients and aged-matched controls had significantly lesser EBV-specific CTL than younger healthy individuals. Multimer positive populations from either group did not differ with respect to the percentage of multimer positive CTLs and the intensity of multimer binding.</p> <p>Conclusions</p> <p>This study provides evidence that patients with lung cancer exhibit an EBV-specific CTL response equivalent to that of age-matched healthy counterparts. These data warrant the examination of whether young individuals have a more robust anti-tumor response, as is the case with the anti-EBV response.</p
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