889 research outputs found
Towards a Generalized Distribution Formalism for Gauge Quantum Fields
We prove that the distributions defined on the Gelfand-Shilov spaces, and
hence more singular than hyperfunctions, retain the angular localizability
property. Specifically, they have uniquely determined support cones. This
result enables one to develop a distribution-theoretic techniques suitable for
the consistent treatment of quantum fields with arbitrarily singular
ultraviolet and infrared behavior. The proofs covering the most general case
are based on the use of the theory of plurisubharmonic functions and
Hormander's estimates.Comment: 12 p., Department of Theoretical Physics, P.N.Lebedev Physical
Institute, Leninsky prosp. 53, Moscow 117924, Russi
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A general technique for characterizing x-ray position sensitive arrays
We present a general statistical technique for characterizing x-ray sensitive linear diode arrays and CCD arrays. We apply this technique to characterize the response of a linear diode array, Princeton Instrument model X-PDA, and a virtual phase CCD array, TI 4849, to direct illumination by x-rays. We find that the response of the linear array is linearly proportional to the incident intensity and uniform over its length to within 2 %. Its quantum efficiency is 38 % for Cu K{sub {alpha}} x-rays. The resolution function is evaluated from the spatial autocorrelation function and falls to 10 % of its peak value after one pixel. On the other hand, the response of the CCD detecting system to direct x-ray exposure is non-linear. To properly quantify the scattered x-rays, one must correct for the non- linearity. The resolution is two pixels along the serial transfer direction. We characterize the noise of the CCD and propose a model that takes into account the non-linearity and the resolution function to estimate the quantum efficiency of the detector. The quantum efficiency is 20 %
A Magnetic Transition Probed by the Ce Ion in Square-Lattice Antiferromagnet CeMnAsO
We examined the magnetic properties of the square-lattice antiferromagnets
CeMnAsO and LaMnAsO and their solid solutions La1-xCexMnAsO by resistivity,
magnetic susceptibility, and heat capacity measurements below room temperature.
A first-order phase transition is observed at 34.1 K, below which the
ground-state doublet of the Ce ion splits by 3.53 meV. It is likely that Mn
moments already ordered above room temperature are reoriented at the
transition, as reported for related compounds, such as NdMnAsO and PrMnSbO.
This transition generates a large internal magnetic field at the Ce site in
spite of the fact that simple Heisenberg interactions should be cancelled out
at the Ce site owing to geometrical frustration. The transition takes place at
nearly the same temperature with the substitution of La for Ce up to 90%. The
Ce moment does not undergo long-range order by itself, but is parasitically
induced at the transition, serving as a good probe for detecting the magnetism
of Mn spins in a square lattice.Comment: 11 pages, 5 figures, to be published in J. Phys. Soc. Jp
Harnessing RNA sequencing for global, unbiased evaluation of two new adjuvants for dendritic-cell immunotherapy
Effective stimulation of immune cells is crucial for the success of cancer immunotherapies. Current approaches to evaluate the efficiency of stimuli are mainly defined by known flow cytometry-based cell activation or cell maturation markers. This method however does not give a complete overview of the achieved activation state and may leave important side effects unnoticed. Here, we used an unbiased RNA sequencing (RNA-seq)-based approach to compare the capacity of four clinical-grade dendritic cell (DC) activation stimuli used to prepare DC-vaccines composed of various types of DC subsets; the already clinically applied GM-CSF and Frühsommer meningoencephalitis (FSME) prophylactic vaccine and the novel clinical grade adjuvants protamine-RNA complexes (pRNA) and CpG-P. We found that GM-CSF and pRNA had similar effects on their target cells, whereas pRNA and CpG-P induced stronger type I interferon (IFN) expression than FSME. In general, the pathways most affected by all stimuli were related to immune activity and cell migration. GM-CSF stimulation, however, also induced a significant increase of genes related to nonsense-mediated decay, indicating a possible deleterious effect of this stimulus. Taken together, the two novel stimuli appear to be promising alternatives. Our study demonstrates how RNA-seq based investigation of changes in a large number of genes and gene groups can be exploited for fast and unbiased, global evaluation of clinical-grade stimuli, as opposed to the general limited evaluation of a pre-specified set of genes, by which one might miss important biological effects that are detrimental for vaccine efficacy
, and the neutrino mass hierarchy at a double baseline Li/B -Beam
We consider a -Beam facility where Li and B ions are
accelerated at , accumulated in a 10 Km storage ring and let
decay, so as to produce intense and beams. These beams
illuminate two iron detectors located at Km and
Km, respectively. The physics potential of this setup is analysed in full
detail as a function of the flux. We find that, for the highest flux ( ion decays per year per baseline), the sensitivity to
reaches ; the sign of
the atmospheric mass difference can be identified, regardless of the true
hierarchy, for ; and, CP-violation
can be discovered in 70% of the -parameter space for , having some sensitivity to CP-violation down to
for .Comment: 35 pages, 20 figures. Minor changes, matches the published versio
Euclidean Approach to the Entropy for a Scalar Field in Rindler-like Space-Times
The off-shell entropy for a massless scalar field in a D-dimensional
Rindler-like space-time is investigated within the conical Euclidean approach
in the manifold C_\be\times\M^N, C_\be being the 2-dimensional cone, making
use of the zeta-function regularisation. Due to the presence of conical
singularities, it is shown that the relation between the zeta-function and the
heat kernel is non trivial and, as first pointed out by Cheeger, requires a
separation between small and large eigenvalues of the Laplace operator. As a
consequence, in the massless case, the (naive) non existence of the Mellin
transform is by-passed by the Cheeger's analytical continuation of the
zeta-function on manifold with conical singularities. Furthermore, the
continuous spectrum leads to the introduction of smeared traces. In general, it
is pointed out that the presence of the divergences may depend on the smearing
function and they arise in removing the smearing cutoff. With a simple choice
of the smearing function, horizon divergences in the thermodynamical quantities
are recovered and these are similar to the divergences found by means of
off-shell methods like the brick wall model, the optical conformal
transformation techniques or the canonical path integral method.Comment: 17 pages, LaTex. A sign error corrected and few comments adde
Boundary relations and generalized resolvents of symmetric operators
The Kre\u{\i}n-Naimark formula provides a parametrization of all selfadjoint
exit space extensions of a, not necessarily densely defined, symmetric
operator, in terms of maximal dissipative (in \dC_+) holomorphic linear
relations on the parameter space (the so-called Nevanlinna families). The new
notion of a boundary relation makes it possible to interpret these parameter
families as Weyl families of boundary relations and to establish a simple
coupling method to construct the generalized resolvents from the given
parameter family. The general version of the coupling method is introduced and
the role of boundary relations and their Weyl families for the
Kre\u{\i}n-Naimark formula is investigated and explained.Comment: 47 page
Quantum Fields in Hyperbolic Space-Times with Finite Spatial Volume
The one-loop effective action for a massive self-interacting scalar field is
investigated in -dimensional ultrastatic space-time ,
being a non-compact hyperbolic manifold with finite volume. Making
use of the Selberg trace formula, the -function related to the small
disturbance operator is constructed. For an arbitrary gravitational coupling,
it is found that has a simple pole at . The one-loop effective
action is analysed by means of proper-time regularisations and the one-loop
divergences are explicitly found. It is pointed out that, in this special case,
also -function regularisation requires a divergent counterterm, which
however is not necessary in the free massless conformal invariant coupling
case. Finite temperature effects are studied and the high-temperature expansion
is presented. A possible application to the problem of the divergences of the
entanglement entropy for a free massless scalar field in a Rindler-like
space-time is briefly discussed.Comment: 13 pages, LaTex. The contribution of hyperbolic elements has been
added. Other minor corrections and reference
Annotated bibliography "Arabic papyrology and diplomatics": new publications 2018 and addenda 2017
Middle Eastern Studie
Loss of the coxsackie and adenovirus receptor contributes to gastric cancer progression
Loss of the coxsackie and adenovirus receptor (CAR) has previously been observed in gastric cancer. The role of CAR in gastric cancer pathobiology, however, is unclear. We therefore analysed CAR in 196 R0-resected gastric adenocarcinomas and non-cancerous gastric mucosa samples using immunohistochemistry and immunofluorescence. Coxsackie and adenovirus receptor was found at the surface and foveolar epithelium of all non-neoplastic gastric mucosa samples (n=175), whereas only 56% of gastric cancer specimens showed CAR positivity (P<0.0001). Loss of CAR correlated significantly with decreased differentiation, increased infiltrative depths, presence of distant metastases, and was also associated with reduced carcinoma-specific survival. To clarify whether CAR impacts the tumorbiologic properties of gastric cancer, we subsequently determined the role of CAR in proliferation, migration, and invasion of gastric cancer cell lines by application of specific CAR siRNA or ectopic expression of a human full-length CAR cDNA. These experiments showed that RNAi-mediated CAR knock down resulted in increased proliferation, migration, and invasion of gastric cancer cell lines, whereas enforced ectopic CAR expression led to opposite effects. We conclude that the association of reduced presence of CAR in more severe disease states, together with our findings in gastric cancer cell lines, suggests that CAR functionally contributes to gastric cancer pathogenesis, showing features of a tumour suppressor
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