3,421 research outputs found

    Self-Similar Random Processes and Infinite-Dimensional Configuration Spaces

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    We discuss various infinite-dimensional configuration spaces that carry measures quasiinvariant under compactly-supported diffeomorphisms of a manifold M corresponding to a physical space. Such measures allow the construction of unitary representations of the diffeomorphism group, which are important to nonrelativistic quantum statistical physics and to the quantum theory of extended objects in d-dimensional Euclidean space. Special attention is given to measurable structure and topology underlying measures on generalized configuration spaces obtained from self-similar random processes (both for d = 1 and d > 1), which describe infinite point configurations having accumulation points

    On the Fock space for nonrelativistic anyon fields and braided tensor products

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    We realize the physical N-anyon Hilbert spaces, introduced previously via unitary representations of the group of diffeomorphisms of the plane, as N-fold braided-symmetric tensor products of the 1-particle Hilbert space. This perspective provides a convenient Fock space construction for nonrelativistic anyon quantum fields along the more usual lines of boson and fermion fields, but in a braided category. We see how essential physical information is thus encoded. In particular we show how the algebraic structure of our anyonic Fock space leads to a natural anyonic exclusion principle related to intermediate occupation number statistics, and obtain the partition function for an idealised gas of fixed anyonic vortices.Comment: Added some references, more explicit formulae for the discrete case and remark on partition function. 25 pages latex, no figure

    On the virial coefficients of nonabelian anyons

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    We study a system of nonabelian anyons in the lowest Landau level of a strong magnetic field. Using diagrammatic techniques, we prove that the virial coefficients do not depend on the statistics parameter. This is true for all representations of all nonabelian groups for the statistics of the particles and relies solely on the fact that the effective statistical interaction is a traceless operator.Comment: 9 pages, 3 eps figure

    Gauge Transformations in Quantum Mechanics and the Unification of Nonlinear Schr\"odinger Equations

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    Beginning with ordinary quantum mechanics for spinless particles, together with the hypothesis that all experimental measurements consist of positional measurements at different times, we characterize directly a class of nonlinear quantum theories physically equivalent to linear quantum mechanics through nonlinear gauge transformations. We show that under two physically-motivated assumptions, these transformations are uniquely determined: they are exactly the group of time-dependent, nonlinear gauge transformations introduced previously for a family of nonlinear Schr\"odinger equations. The general equation in this family, including terms considered by Kostin, by Bialynicki-Birula and Mycielski, and by Doebner and Goldin, with time-dependent coefficients, can be obtained from the linear Schr\"odinger equation through gauge transformation and a subsequent process we call gauge generalization. We thus unify, on fundamental grounds, a rather diverse set of nonlinear time-evolutions in quantum mechanics.Comment: RevTeX, 20 pages, no figures. also available on http://www.pt.tu-clausthal.de/preprints/asi-tpa/021-96.htm

    Thermal destruction of vessels with liquid upon heating

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    A new engineering technique of calculating the heating and thermal destruction of vessels containing liquid under extreme thermal loading conditions is offered. The heating of the shell and the internal vessel volume is described on the basis of the thermodynamic approach. The pressure growth in a vessel is a result of gas heating and liquid evaporation. Stresses within the shell and its destruction conditions are determined, which allows predicting the critical time of destruction upon heating. The calculation and experimental data for pressure growth inside the vessel are in good agreement

    Voltage-gated sodium channels (NaV) in GtoPdb v.2021.3

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    Sodium channels are voltage-gated sodium-selective ion channels present in the membrane of most excitable cells. Sodium channels comprise of one pore-forming α subunit, which may be associated with either one or two β subunits [177]. α-Subunits consist of four homologous domains (I-IV), each containing six transmembrane segments (S1-S6) and a pore-forming loop. The positively charged fourth transmembrane segment (S4) acts as a voltage sensor and is involved in channel gating. The crystal structure of the bacterial NavAb channel has revealed a number of novel structural features compared to earlier potassium channel structures including a short selectivity filter with ion selectivity determined by interactions with glutamate side chains [274]. Interestingly, the pore region is penetrated by fatty acyl chains that extend into the central cavity which may allow the entry of small, hydrophobic pore-blocking drugs [274]. Auxiliary β1, β2, β3 and β4 subunits consist of a large extracellular N-terminal domain, a single transmembrane segment and a shorter cytoplasmic domain.The nomenclature for sodium channels was proposed by Goldin et al., (2000) [144] and approved by the NC-IUPHAR Subcommittee on sodium channels (Catterall et al., 2005, [52])

    Voltage-gated sodium channels (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

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    Sodium channels are voltage-gated sodium-selective ion channels present in the membrane of most excitable cells. Sodium channels comprise of one pore-forming α subunit, which may be associated with either one or two β subunits [176]. α-Subunits consist of four homologous domains (I–IV), each containing six transmembrane segments (S1–S6) and a pore-forming loop. The positively charged fourth transmembrane segment (S4) acts as a voltage sensor and is involved in channel gating. The crystal structure of the bacterial NavAb channel has revealed a number of novel structural features compared to earlier potassium channel structures including a short selectivity filter with ion selectivity determined by interactions with glutamate side chains [268]. Interestingly, the pore region is penetrated by fatty acyl chains that extend into the central cavity which may allow the entry of small, hydrophobic pore-blocking drugs [268]. Auxiliary β1, β2, β3 and β4 subunits consist of a large extracellular N-terminal domain, a single transmembrane segment and a shorter cytoplasmic domain.The nomenclature for sodium channels was proposed by Goldin et al., (2000) [143] and approved by the NC-IUPHAR Subcommittee on sodium channels (Catterall et al., 2005, [51])

    Voltage-gated sodium channels (NaV) in GtoPdb v.2023.1

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    Sodium channels are voltage-gated sodium-selective ion channels present in the membrane of most excitable cells. Sodium channels comprise of one pore-forming α subunit, which may be associated with either one or two β subunits [179]. α-Subunits consist of four homologous domains (I-IV), each containing six transmembrane segments (S1-S6) and a pore-forming loop. The positively charged fourth transmembrane segment (S4) acts as a voltage sensor and is involved in channel gating. The crystal structure of the bacterial NavAb channel has revealed a number of novel structural features compared to earlier potassium channel structures including a short selectivity filter with ion selectivity determined by interactions with glutamate side chains [278]. Interestingly, the pore region is penetrated by fatty acyl chains that extend into the central cavity which may allow the entry of small, hydrophobic pore-blocking drugs [278]. Auxiliary β1, β2, β3 and β4 subunits consist of a large extracellular N-terminal domain, a single transmembrane segment and a shorter cytoplasmic domain.The nomenclature for sodium channels was proposed by Goldin et al., (2000) [146] and approved by the NC-IUPHAR Subcommittee on sodium channels (Catterall et al., 2005, [53])

    Polyamine metabolism in compensatory renal growth

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    Compensatory renal growth, following renal mass extirpation, is accompanied by multiple biochemical alterations including increased nucleic acid, protein, and polyamine synthesis. The aliphatic polyamines-putrescine, spermidine, and spermine are found in most living organisms and appear to participate in many forms of augmented growth including embryonic, regenerative, hormone-induced, and neoplastic [1–3]. While the precise biochemical function of these compounds has not been defined, increased levels of polyamines and their biosynthetic enzymes occur in association with enhanced nucleic acid and protein synthesis in rapidly growing tissues [3–6]. Polyamines apparently contribute to nucleic acid accumulation by promoting biosynthesis and retarding degradation [6–8]. The decarboxylation of ornithine to putrescine is the rate-limiting step in polyamine synthesis. The catalyst, ornithine decarboxylase, is very inducible and has a short half-life in both normal and regenerating liver (10 to 11 min) [5]. Changes in enzyme activity precede or occur simultaneously with increases in RNA, DNA, and protein concentrations [3].In this study, alterations in renal polyamine synthesis were investigated in conjunction with other evidences of stimulated kidney growth following unilateral nephrectomy. These data are discussed in the context of previous observations regarding polyamine biosynthesis during enhanced renal growth
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