647 research outputs found
Topological gravity on plumbed V-cobordisms
An ensemble of cosmological models based on generalized BF-theory is
constructed where the role of vacuum (zero-level) coupling constants is played
by topologically invariant rational intersection forms (cosmological-constant
matrices) of 4-dimensional plumbed V-cobordisms which are interpreted as
Euclidean spacetime regions. For these regions describing topology changes, the
rational and integer intersection matrices are calculated. A relation is found
between the hierarchy of certain elements of these matrices and the hierarchy
of coupling constants of the universal (low-energy) interactions.
PACS numbers: 0420G, 0240, 0460Comment: 29 page
Multidimensional Toda type systems
On the base of Lie algebraic and differential geometry methods, a wide class
of multidimensional nonlinear systems is obtained, and the integration scheme
for such equations is proposed.Comment: 29 pages, LaTeX fil
Патологии метаподий древних копытных
This report describes pathological changes of twelve metapodial bones of ancient large ungulates (Bison priscus, Cervus elaphus, Megaloceros giganteus, Equus ex gr. gallicus) from various sites in West Siberia. Two basic types of deteriorations were observed: proximal epiphyseal deformity resulting from arthrosis, and periosteal proliferations on diaphysis. All of these likely are related to trauma. The most probable causes of the injuries include unsuccessful hunting activity of cave lions and environment-associated sharp or blunt force
Neuro-Insular Complexes in the Human Pancreas
It is well known that pancreatic islets are complex structures composed of endodermally derived endocrine cells, integrated with endothelial cells and other cells, originating from the mesoderm, and innervated by nerve fibers that have a neuroectodermal origin. In our studies, we focused on the interactions between the structures of the nervous system and endocrine cells, the so-called neuro-insular complexes, in the human pancreas. In this chapter, we present our results and literature data concerning the morphological organization of neuro-insular complexes in humans and other mammals. We also discuss the possible functional role of neuro-insular complexes, such as the involvement of the nervous system in the regulation and synchronization of islet hormone secretion and the morphogenetic plasticity of the endocrine pancreas in adults, as well as in the regulation of endocrine cell proliferation and maturation during prenatal development of the pancreas
Development of Human Pancreatic Innervation
Human pancreatic innervation is of particular interest due to its possible role in the pathogenesis of such diseases as diabetes mellitus, pancreatitis and pancreatic cancer. Despite the clinical importance, data concerning pancreatic innervation during human ontogeny and in various disorders are very limited. In this chapter, we present a review on human pancreatic autonomic innervation on the basis of the literature data and our previous results. Special attention is paid to the innervation of the endocrine pancreas. Gradual branching of neural network was seen during human pancreatic development. Innervation of the foetal pancreas is more abundant than in adults. In agreement with previous observations, we have revealed a close integration and similarity between endocrine cells and nervous elements in the developing human pancreas. Moreover, simultaneous interactions between the nervous system components, epithelial cells and endocrine cells were detected in the pancreas during prenatal human development. It has been suggested that pancreatic innervation plays an important role not only in regulation of endocrine and exocrine activity but also in normal islet morphogenesis
Kinetic Force Method with Quasiparticle Pairs for Numerical Modeling 3D Rarefied Gas Flows
Abstract. In the paper a new way of Kinetic Force Method application for modeling rarefied gas flows is suggested. This way is founded on a kinetic equation for auxiliary two-particle distribution function of quasiparticle pairs. One-particle distribution function satisfying the classical Boltzmann equation can be obtained from the auxiliary distribution function by a simple integration. The using of quasiparticle pairs guarantees energy and momentum conservation in the course of the rarefied gas flows modeling automatically. Comparison of the results obtained by Kinetic Force Method and DSMC method is carried out on the examples of numerical simulations of the homogeneous relaxation and the vacuum pump micro flows
Silicon Avalanche Pixel Sensor for High Precision Tracking
The development of an innovative position sensitive pixelated sensor to
detect and measure with high precision the coordinates of the ionizing
particles is proposed. The silicon avalanche pixel sensors (APiX) is based on
the vertical integration of avalanche pixels connected in pairs and operated in
coincidence in fully digital mode and with the processing electronics embedded
on the chip. The APiX sensor addresses the need to minimize the material budget
and related multiple scattering effects in tracking systems requiring a high
spatial resolution in the presence of a large occupancy. The expected operation
of the new sensor features: low noise, low power consumption and suitable
radiation tolerance. The APiX device provides on-chip digital information on
the position of the coordinate of the impinging charged particle and can be
seen as the building block of a modular system of pixelated arrays,
implementing a sparsified readout. The technological challenges are the 3D
integration of the device under CMOS processes and integration of processing
electronics.Comment: 13th Topical Seminar on Innovative Particle and Radiation Detectors
IPRD1
The sl(2n|2n)^(1) Super-Toda Lattices and the Heavenly Equations as Continuum Limit
The continuum limit of super-Toda models associated with the
affine (super)algebra series produces -dimensional
integrable equations in the spacetimes. The
equations of motion of the (super)Toda hierarchies depend not only on the
chosen (super)algebras but also on the specific presentation of their Cartan
matrices. Four distinct series of integrable hierarchies in relation with
symmetric-versus-antisymmetric, null-versus-nonnull presentations of the
corresponding Cartan matrices are investigated. In the continuum limit we
derive four classes of integrable equations of heavenly type, generalizing the
results previously obtained in the literature. The systems are manifestly N=1
supersymmetric and, for specific choices of the Cartan matrix preserving the
complex structure, admit a hidden N=2 supersymmetry. The coset reduction of the
(super)-heavenly equation to the spacetime (with a line segment) is
illustrated. Finally, integrable supersymmetrically extended models in
dimensions are constructed through dimensional reduction of the
previous systems.Comment: 12 page
Magnetoelectric direct and converse resonance effects in a flexible ferromagnetic-piezoelectric polymer structure
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