3,150 research outputs found
Direct test of time-reversal symmetry in the entangled neutral kaon system at a -factory
We present a novel method to perform a direct T (time reversal) symmetry test
in the neutral kaon system, independent of any CP and/or CPT symmetry tests.
This is based on the comparison of suitable transition probabilities, where the
required interchange of in out states for a given process is obtained
exploiting the Einstein-Podolsky-Rosen correlations of neutral kaon pairs
produced at a -factory. In the time distribution between the two decays,
we compare a reference transition like the one defined by the time ordered
decays with the T -conjugated one defined by . With the use of this and other T conjugated comparisons, the KLOE-2
experiment at DANE could make a significant test
Precision Measurement of KS Meson Lifetime with the KLOE detector
Using a large sample of pure, slow, short lived K0 mesons collected with KLOE
detector at DaFne, we have measured the KS lifetime. From a fit to the proper
time distribution we find tau = (89.562 +- 0.029_stat +- 0.043_syst) ps. This
is the most precise measurement today in good agreement with the world average
derived from previous measurements. We observe no dependence of the lifetime on
the direction of the Ks.Comment: 5 pages, 7 figure
CP Measurement in Quantum Teleportation of Neutral Mesons
Quantum teleportation using neutral pseudoscalar mesons shows novel
connections between particle physics and quantum information. The projection
basis, which is crucial in the teleportation process, is determined by the
conservation laws of particle physics, and is different from the Bell basis, as
in the usual case. Here we show that one can verify the teleportation process
by CP measurement. This method significantly simplifies the high energy quantum
teleportation protocol. Especially, it is rigorous, and is independent of
whether CP is violated in weak decays. This method can also be applied to
general verification of Einstein-Podolsky-Rosen correlations in particle
physics.Comment: 7 page
Signal amplification by combining two advanced immunohistochemical techniques
The immunohistochemical techniques known as EnVision™+ System (EVS) and Mirror Image Complementary Antibody (MICA) were recently introduced into laboratory practice because of their high sensitivity. In this paper these techniques were compared and their sequences combined to obtain a new method possibly more sensitive than the original ones. The immunohistochemical staining employing the avidin-biotin complex (ABC), largely used as routine, was adopted as a term of comparison. Samples from the small and large intestine of pigs and sheep were fixed in Bouin and embedded in Paraplast. The primary antibodies utilized were directed against the neuronal nitric oxide synthase (nNOS), vasoactive intestinal polypeptide (VIP) and chromogranin A (Cr A). Targets of these antibodies were nerve structures of the intestinal wall, as well as endocrine cells scattered in the mucosa of the bowel, defined neuroendocrine cells or paraneurons. The EVS method appeared as slightly superior to the MICA method regarding sensitivity of detection. The EVS/MICA (combined) method resulted four/eight times more effective than the original techniques regarding sensitivity of detection and staining intensity, both at low and high dilutions of the primary antibodies. Of these latter, immunopositive structures were still clearly identifiable, at a dilution of 1:256,000. Such efficiency could be explained by the high number of revealing molecules of peroxidase contained in the new sequence. The application of the combined method is recommended when a small quantity of tissue antigens needs to be detected immunohistochemically
A Constructive Heuristics and an Iterated Neighborhood Search Procedure to Solve the Cost-Balanced Path Problem
This paper presents a new heuristic algorithm tailored to solve large instances of an NP-hard variant of the shortest path problem, denoted the cost-balanced path problem, recently proposed in the literature. The problem consists in finding the origin–destination path in a direct graph, having both negative and positive weights associated with the arcs, such that the total sum of the weights of the selected arcs is as close to zero as possible. At least to the authors’ knowledge, there are no solution algorithms for facing this problem. The proposed algorithm integrates a constructive procedure and an improvement procedure, and it is validated thanks to the implementation of an iterated neighborhood search procedure. The reported numerical experimentation shows that the proposed algorithm is computationally very efficient. In particular, the proposed algorithm is most suitable in the case of large instances where it is possible to prove the existence of a perfectly balanced path and thus the optimality of the solution by finding a good percentage of optimal solutions in negligible computational time
Study of isospin violating excitation in
We study the reaction in the vicinity of mass
region. The isospin-violating excitation is accounted for by two major
mechanisms. One is electromagnetic (EM) transition and the other is strong
isospin violations. For the latter, we consider contributions from the
intermediate hadronic meson loops and - mixing as the major
mechanisms via the and s-channel transitions, respectively. By fitting the
recent KLOE data, we succeed in constraining the model parameters and
extracting the branching ratio. It shows that the
branching ratio is sensitive to the excitation line shape and background
contributions. Some crucial insights into the correlation between isospin
violation and Okubo-Zweig-Iizuka (OZI) rule evading transitions are also
learned.Comment: Revised version to appear in J. Phys.
CPT and Lorentz violation as signatures for Planck-scale physics
In recent years, the breakdown of spacetime symmetries has been identified as
a promising research field in the context of Planck-scale phenomenology. For
example, various theoretical approaches to the quantum-gravity problem are
known to accommodate minute violations of CPT invariance. This talk covers
various topics within this research area. In particular, some mechanisms for
spacetime-symmetry breaking as well as the Standard-Model Extension (SME) test
framework will be reviewed; the connection between CPT and Lorentz invariance
in quantum field theory will be exposed; and various experimental CPT tests
with emphasis on matter--antimatter comparisons will be discussed.Comment: 6 page
A New Fast Silicon Photomultiplier Photometer
The realization of low-cost instruments with high technical performance is a
goal which deserves some efforts in an epoch of fast technological
developments: indeed such instruments can be easily reproduced and therefore
allow to open new research programs in several Observatories. We realized a
fast optical photometer based on the SiPM technology, using commercially
available modules. Using low-cost components we have developed a custom
electronic chain to extract the signal produced by a commercial MPPC module
produced by Hamamatsu, in order to obtain sub millisecond sampling of the light
curve of astronomical sources, typically pulsars. In the early February 2011 we
observed the Crab Pulsar at the Cassini telescope with our prototype
photometer, deriving its period, power spectrum and shape of its light curve in
very good agreement with the results obtained in the past with other
instruments.Comment: Accepted for Publications of the Astronomical Society of Pacific
(PASP), 8 pages, 8 figure
The effect of estrogen and tamoxifen on hepatocyte proliferation in Vivo and in Vitro
We have previously shown that changes in estrogen‐hepatocyte interaction occur during liver regeneration. Following 70% hepatectomy, estrogen levels in the blood were elevated, the number of estrogen receptors in the liver was increased and there was an active translocation of estrogen receptors from the cytosol to the nucleus. The injection of tamoxifen, an estrogen antagonist, inhibits hepatocyte proliferation following partial hepatectomy. The administration of 1 μg tamoxifen per gm body weight at zero time or 6 hr after the operation resulted in a significant inhibition both of DNA synthesis and of the number of cells in mitosis. Injections of tamoxifen 12 hr or later after the operation had no effect. Concomitant injections of equimolar amounts of estrogen abolished the inhibition by tamoxifen. The effects of estrogen and tamoxifen were also tested on hepatocytes in primary culture. Estrogens in the presence of 5% normal rat serum stimulated hepatocyte DNA synthesis as determined by [3H]thymidine incorporation and the labeling index, whereas epidermal growth factor‐induced DNA synthesis in the absence of normal rat serum was strongly inhibited. Tamoxifen, in contrast, inhibited DNA synthesis of hepatocytes in the presence of 5% normal rat serum and reversed the stimulatory effect of estrogen in the same system. Attempts to elucidate the mechanism of tamoxifen inhibition in vitro indicated that one effect of tamoxifen is to prevent the amiloride‐sensitive Na+ influx necessary to initiate hepatocyte proliferation. Copyright © 1989 American Association for the Study of Liver Disease
- …