6,354 research outputs found
The effect of electron surface scattering on fine metal particle electromagnetic radiation absorption
The magnetic dipole absorption cross section of a spherically shaped metal
particle was calculated in terms of kinetic approach. The particle considered
was placed in the field of a plane electromagnetic wave. The model of boundary
conditions was investigated taking into account the dependence of the
reflectivity coefficient both on the surface roughness parameter and on the
electron incidence angle. The results obtained were compared with theoretical
computation results for a model of combined diffusion-specular boundary
conditions of Fuchs.Comment: 9 pages, 5 figure
Long-distance entanglement and quantum teleportation in XX spin chains
Isotropic XX models of one-dimensional spin-1/2 chains are investigated with
the aim to elucidate the formal structure and the physical properties that
allow these systems to act as channels for long-distance, high-fidelity quantum
teleportation. We introduce two types of models: I) open, dimerized XX chains,
and II) open XX chains with small end bonds. For both models we obtain the
exact expressions for the end-to-end correlations and the scaling of the energy
gap with the length of the chain. We determine the end-to-end concurrence and
show that model I) supports true long-distance entanglement at zero
temperature, while model II) supports {\it ``quasi long-distance''}
entanglement that slowly falls off with the size of the chain. Due to the
different scalings of the gaps, respectively exponential for model I) and
algebraic in model II), we demonstrate that the latter allows for efficient
qubit teleportation with high fidelity in sufficiently long chains even at
moderately low temperatures.Comment: 9 pages, 6 figure
Morpho-functional basis of endothelial dysfunction in diabetes mellitus
The diabetes mellitus (DM) inevitably progresses and leads to complications, among which the main place is occupied by micro- and macroangiopathies. The presence of endothelial damage in DM can be established even before macroscopically significant damage to the vessel. At the same time, there is no summary ED characteristic for diabetes. The aim of the study is to make a comprehensive evaluation of ED in DM -1 and DM-2 types.Materials and methods of research. 60 persons, including 53 DM type 1 and type 2, with a severe course (state of decompensation) participated in the present study. We used the method of estimating ED by the number of circulating desquamation endothelial cells (CECs) at the stages of decomposition with simultaneous determination of NO2- and NO3- metabolites of nitric oxide.Results and discussion. In patients with diabetes, the level of CECs increased in 3-5 times and ranged from 1800 to 11,200 cells / ml. The average amount of CECs in patients with diabetes was 3358.5 ± 366.3 cells / ml.Conclusions: Endothelium is involved in the pathological process at DM. This is evidenced by a significant increase in CECs in the blood plasma. The use of this method allows to detect ED before clinically considerable vascular impairment and reflects the severity of the course and duration of DM
Conditioned reflex activity of rats at later periods after the end of flight aboard the Kosmos-605 biosatellite
The aftereffects of spaceflight on the higher nervous activity of rats were studied. A five lane maze with a feeding terminal was used to check such factors as transfer of experience, the habit and speed of reaching the goal in the maze, long term memory, and the dynamics of errors. During the 3rd-7th postflight week, functional disturbances in the rat HNA were manifested in the deterioration of the capacity for the transfer of experience and for locating the feeding compartment in the maze, thus indicating a general decrease of work capacity. The increased number of errors and failures pointed to exhaustion of higher nervous processes and to the weakened functional activity of the brain
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