2,553 research outputs found
Non-homogeneous random walks, subdiffusive migration of cells and anomalous chemotaxis
This paper is concerned with a non-homogeneous in space and non-local in time
random walk model for anomalous subdiffusive transport of cells. Starting with
a Markov model involving a structured probability density function, we derive
the non-local in time master equation and fractional equation for the
probability of cell position. We show the structural instability of fractional
subdiffusive equation with respect to the partial variations of anomalous
exponent. We find the criteria under which the anomalous aggregation of cells
takes place in the semi-infinite domain.Comment: 18 pages, accepted for publicatio
Space-Charge and resonance considerations for choosing the SNS ring working points
The beam power of the SNS is an order of magnitude higher than that of existing accelerator facilities. This imposes a strict requirement on the uncontrolled beam loss at a level. The major source of beam loss is associated with machine resonances. Thus, the first step towards reaching low beam loss is to find the best suitable working points on the tune diagram. In this note, we explore the tune space by considering machine resonances and the effect of space charge, which can drive particles into these excited resonances.In addition, space charge itself can induce resonances. Our present studies were driven by these facts and by the fact that previous working points [1] were identified for the shorter ring with 220 m circumference. Also, the combined effects of space charge and magnet errors raised concern for the nominal working point [2-3]
Beam test results of 3D fine-grained scintillator detector prototype for a T2K ND280 neutrino active target
An upgrade of the long baseline neutrino experiment T2K near detector ND280
is currently being developed with the goal to reduce systematic uncertainties
in the prediction of number of events at the far detector Super-Kamiokande. The
upgrade program includes the design and construction of a new highly granular
fully active scintillator detector with 3D WLS fiber readout as a neutrino
target. The detector of about in size and a mass
of 2.2~tons will be assembled from about plastic
scintillator cubes of . Each cube is read out by three
orthogonal Kuraray Y11 Wave Length Shifting (WLS) fibers threaded through the
detector. A detector prototype made of 125 cubes was assembled and tested in a
charged particle test beam at CERN in the fall of 2017. This paper presents the
results obtained on the light yield and timing as well as on the optical
cross-talk between the cubes.Comment: 5 pages, 8 figure
A toy model of fractal glioma development under RF electric field treatment
A toy model for glioma treatment by a radio frequency electric field is
suggested. This low-intensity, intermediate-frequency alternating electric
field is known as the tumor-treating-field (TTF). In the framework of this
model the efficiency of this TTF is estimated, and the interplay between the
TTF and the migration-proliferation dichotomy of cancer cells is considered.
The model is based on a modification of a comb model for cancer cells, where
the migration-proliferation dichotomy becomes naturally apparent. Considering
glioma cancer as a fractal dielectric composite of cancer cells and normal
tissue cells, a new effective mechanism of glioma treatment is suggested in the
form of a giant enhancement of the TTF. This leads to the irreversible
electroporation that may be an effective non-invasive method of treating brain
cancer.Comment: Submitted for publication in European Physical Journal
Metamaterial with polarization and direction insensitive resonant transmission response mimicking electromagnetically induced transparency
We report on a planar metamaterial, the resonant transmission frequency of which does not depend on the polarization and angle of incidence of electromagnetic waves. The resonance results from the excitation of high-Q antisymmetric trapped current mode and shows sharp phase dispersion characteristic to Fano-type resonances of the electromagnetically induced transparency phenomenon
Metamaterials: optical activity without chirality
We report that the classical phenomenon of optical activity, which is traditionally associated with chirality (helicity) of organic molecules, proteins, and inorganic structures, can be observed in artificial planar media which exhibit neither 3D nor 2D chirality. We observe the effect in the microwave and optical parts of the spectrum at oblique incidence to regular arrays of nonchiral subwavelength metamolecules in the form of strong circular dichroism and birefringence indistinguishable from those of chiral three-dimensional media
New Methods of Three-Dimensional Images Recognition Based on Stochastic Geometry and Functional Analysis
A new approach to 3D objects recognition based on modern methods of stochastic geometry and functional analysis is proposed in the paper. A detailed mathematical description of the method developed on the approach is also presented. The 3D trace transform allows creating an invariant description of spatial objects, which better resist distortion and coordinate noise than the one, obtained as a result of the object normalization procedure, does. The ability to control properties of developed features increases intellectual capacities of the 3D trace transform significantly, which can be mentioned as its undeniable advantage. The justification of the proposed theory and mathematical model is a variety of worked out theoretical examples of hypertriplet features that have particular described properties. The paper considers in detail scan techniques of the hypertrace transform and its mathematical model as well as approaches to developing and distinguishing informative features
Application of bent crystals at IHEP 70-GeV accelerator to enhance the efficiency of its usage
Bent crystal was extracting 70-GeV protons with average intensity 4*10^11 (as
measured in external beamline) per spill of 1.6 s duration, in parallel to the
simultaneous work of two internal targets in the accelerator ring. An
additional crystal, placed in the external beamline, was deflecting a small
part of the extracted beam with intensity 10^7 protons toward another physics
experiment. Crystal-extracted beam had a typical size of 4 mm by 4 mm fwhm at
the end of the external beamline. Measurements for the extraction efficiency
and other characteristics at the simultaneous work of four experimental set-ups
are presented. With crystal working in the above-said regime during one month,
no degradation of channeling was observed. The studies of extraction efficiency
have been continued with new crystals.Comment: 6pp. Presented at EPAC 200
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