407 research outputs found
How long is the convex minorant of a one-dimensional random walk?
We prove distributional limit theorems for the length of the largest convex minorant of a one-dimensional random walk with independent identically distributed increments. Depending on the increment law, there are several regimes with different limit distributions for this length. Among other tools, a representation of the convex minorant of a random walk in terms of uniform random permutations is utilized
Theory of temperature dependence of the Fermi surface-induced splitting of the alloy diffuse-scattering intensity peak
The explanation is presented for the temperature dependence of the fourfold
intensity peak splitting found recently in diffuse scattering from the
disordered Cu3Au alloy. The wavevector and temperature dependence of the
self-energy is identified as the origin of the observed behaviour. Two
approaches for the calculation of the self-energy, the high-temperature
expansion and the alpha-expansion, are proposed. Applied to the Cu3Au alloy,
both methods predict the increase of the splitting with temperature, in
agreement with the experimental results.Comment: 4 pages, 3 EPS figures, RevTeX, submitted to J. Phys. Condens. Matter
(Letter to the Editor
Perfect magnetohydrodynamics as a field theory
We propose the generally covariant action for the theory of a self-coupled
complex scalar field and electromagnetism which by virtue of constraints is
equivalent, in the regime of long wavelengths, to perfect magnetohydrodynamics
(MHD). We recover from it the Euler equation with Lorentz force, and the
thermodynamic relations for a prefect fluid. The equation of state of the
latter is related to the scalar field's self potential. We introduce 1+3
notation to elucidate the relation between MHD and field variables. In our
approach the requirement that the scalar field be single valued leads to the
quantization of a certain circulation in steps of ; this feature leads,
in the classical limit, to the conservation of that circulation. The
circulation is identical to that in Oron's generalization of Kelvin's
circulation theorem to perfect MHD; we here characterize the new conserved
helicity associated with it. We also demonstrate the existence for MHD of two
Bernoulli-like theorems for each spacetime symmetry of the flow and geometry;
one of these is pertinent to suitably defined potential flow. We exhibit the
conserved quantities explicitly in the case that two symmetries are
simultaneously present, and give examples. Also in this case we exhibit a new
conserved MHD circulation distinct from Oron's, and provide an example.Comment: RevTeX, 16 pages, no figures; clarifications added and typos
corrected; version to be published in Phys. Rev.
Mechatronical Module Development on the Basis of Wave Rack Gear for Working Members Drive of Automatized Machines
Peculiarities of geometry elements synthesis of wave transmission with a rolling (cog) rack, its kinematics and simulation interaction of discrete wedge pushers with rolling rack are considered here. Principles of drive creation and systems of microprocessor control of the mechatronical module of the translation by using wave transmission with the rolling rack as well as the main appraches in design-technological preparation of its making are presented.Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΡΠΈΠ½ΡΠ΅Π·Π° Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΠΈ ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠ² Π²ΠΎΠ»Π½ΠΎΠ²ΠΎΠΉ ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠΈ Ρ ΡΠΎΠ»ΠΈΠΊΠΎΠ²ΠΎΠΉ (ΡΠ΅Π²ΠΎΡΠ½ΠΎΠΉ) ΡΠ΅ΠΉΠΊΠΎΠΉ, Π΅Π΅ ΠΊΠΈΠ½Π΅ΠΌΠ°ΡΠΈΠΊΠΈ ΠΈ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ Π΄ΠΈΡΠΊΡΠ΅ΡΠ½ΡΡ
ΠΊΠ»ΠΈΠ½ΠΎΠ²ΡΡ
ΡΠΎΠ»ΠΊΠ°ΡΠ΅Π»Π΅ΠΉ Ρ ΡΠΎΠ»ΠΈΠΊΠΎΠ²ΠΎΠΉ ΡΠ΅ΠΉΠΊΠΎΠΉ. ΠΠ·Π»ΠΎΠΆΠ΅Π½Ρ ΠΏΡΠΈΠ½ΡΠΈΠΏΡ ΡΠΎΠ·Π΄Π°Π½ΠΈΡ ΠΏΡΠΈΠ²ΠΎΠ΄Π° ΠΈ ΡΠΈΡΡΠ΅ΠΌΡ ΠΌΠΈΠΊΡΠΎΠΏΡΠΎΡΠ΅ΡΡΠΎΡΠ½ΠΎΠ³ΠΎ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΠΌΠ΅Ρ
Π°ΡΡΠΎΠ½Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄ΡΠ»Ρ ΠΏΠΎΡΡΡΠΏΠ°ΡΠ΅Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΠ΅ΡΠ΅ΠΌΠ΅ΡΠ΅Π½ΠΈΡ Ρ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ΠΌ Π²ΠΎΠ»Π½ΠΎΠ²ΠΎΠΉ ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠΈ Ρ ΡΠΎΠ»ΠΈΠΊΠΎΠ²ΠΎΠΉ ΡΠ΅ΠΉΠΊΠΎΠΉ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ ΠΏΠΎΠ΄Ρ
ΠΎΠ΄Ρ Π² ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΎΡΡΠΊΠΎ-ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΏΠΎΠ΄Π³ΠΎΡΠΎΠ²ΠΊΠ΅ Π΅Π³ΠΎ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²Π°
Antigen-Specific versus Non-Antigen-Specific Immunoadsorption in ABO-Incompatible Renal Transplantation
Introduction: ABO-incompatible (ABOi) renal transplantation (RTx) from living donors is an established procedure to expand the donor pool for patients with end stage renal disease. Immunoadsorption (IA) is a standard procedure for the removal of preformed antibodies against the allograft. In this study, antigen-specific and non-antigen-specific IA in ABOi RTx were compared. Patients and Methods: 10 patients underwent antigen-specific IA (Glycosorb group) and 13 patients non-antigen-specific IA (Immunosorba group). The effects of both procedures regarding antibody reduction, number of treatments, complications, costs, as well as the allograft function and patient survival were compared between both groups. Results: Although the IgG levels were reduced equally by both procedures (p=0.82), the reduction of the IgM level was more effective in the Glycosorb group (p=0.0172). Patients in both groups required a median number of 6 IA before ABOi RTx. Allograft function at one year after AB0i RTx was similar in both groups (estimated glomerular filtration rate: 66 vs. 64 ml/min/1.73mΒ² respectively), with a death-censored graft survival of 90.0% and 92.3% respectively. Complication rates did not differ between procedures. Due to the reuse of non-antigen-specific Immunosorba columns, costs were considerably lower in this group; however, the use of the Immunosorba-based IA was less time-efficient. Conclusion: Considering upcoming alternatives as simultaneous performance of dialysis and IA or a possible reuse of Glycosorb columns, this might become less relevant in the future
Charged multifluids in general relativity
The exact 1+3 covariant dynamical fluid equations for a multi-component
plasma, together with Maxwell's equations are presented in such a way as to
make them suitable for a gauge-invariant analysis of linear density and
velocity perturbations of the Friedmann-Robertson-Walker model. In the case
where the matter is described by a two component plasma where thermal effects
are neglected, a mode representing high-frequency plasma oscillations is found
in addition to the standard growing and decaying gravitational instability
picture. Further applications of these equations are also discussed.Comment: 14 pages (example added), to appear in Class. Quantum Gra
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