16 research outputs found
Non-Life Insurance Pricing: Multi Agents Model
We use the maximum entropy principle for pricing the non-life insurance and
recover the B\"{u}hlmann results for the economic premium principle. The
concept of economic equilibrium is revised in this respect.Comment: 6 pages, revtex
Hamiltonian Study of Improved Lattice Gauge Theory in Three Dimensions
A comprehensive analysis of the Symanzik improved anisotropic
three-dimensional U(1) lattice gauge theory in the Hamiltonian limit is made.
Monte Carlo techniques are used to obtain numerical results for the static
potential, ratio of the renormalized and bare anisotropies, the string tension,
lowest glueball masses and the mass ratio. Evidence that rotational symmetry is
established more accurately for the Symanzik improved anisotropic action is
presented. The discretization errors in the static potential and the
renormalization of the bare anisotropy are found to be only a few percent
compared to errors of about 20-25% for the unimproved gauge action. Evidence of
scaling in the string tension, antisymmetric mass gap and the mass ratio is
observed in the weak coupling region and the behaviour is tested against
analytic and numerical results obtained in various other Hamiltonian studies of
the theory. We find that more accurate determination of the scaling
coefficients of the string tension and the antisymmetric mass gap has been
achieved, and the agreement with various other Hamiltonian studies of the
theory is excellent. The improved action is found to give faster convergence to
the continuum limit. Very clear evidence is obtained that in the continuum
limit the glueball ratio approaches exactly 2, as expected in a
theory of free, massive bosons.Comment: 13 pages, 15 figures, submitted to Phys. Rev.
Finite size correction for fixed word length Zipf analysis
05.45.Tp Time series analysis, 05.40.Jc Brownian motion, 05.10.-a Computational methods in statistical physics and nonlinear dynamics,
Statistical analysis of floating-car data: an empirical study
We present the results of statistical analysis of the
empirical floating-car data. Our investigations are based on
analyzing the time series of four basic quantities namely
velocity, velocity difference, spatial gap and the
acceleration associated to some instrumented cars. We
obtain the statistical characteristics, including the mean,
variance and relative variance of these time series by taking
direct time averages. We also try to identify the moving phases of
the instrumented vehicle according to the statistical properties of
its velocity time series. Moreover, by exploring the two-point
joint probabilities, we propose a new approach for modelling
vehicular dynamics based on the floating car data
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Genotype by random environmental interactions gives an advantage to non-favored minor alleles.
Fixation probability, the probability that the frequency of a newly arising mutation in a population will eventually reach unity, is a fundamental quantity in evolutionary genetics. Here we use a number of models (several versions of the Moran model and the haploid Wright-Fisher model) to examine fixation probabilities for a constant size population where the fitness is a random function of both allelic state and spatial position, despite neither allele being favored on average. The concept of fitness varying with respect to both genotype and environment is important in models of cancer initiation and progression, bacterial dynamics, and drug resistance. Under our model spatial heterogeneity redefines the notion of neutrality for a newly arising mutation, as such mutations fix at a higher rate than that predicted under neutrality. The increased fixation probability appears to be due to rare alleles having an advantage. The magnitude of this effect can be large, and is an increasing function of the spatial variance and skew in fitness. The effect is largest when the fitness values of the mutants and wild types are anti-correlated across environments. We discuss results for both a spatial ring geometry of cells (such as that of a colonic crypt), a 2D lattice and a mass-action (complete graph) arrangement
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Genotype by random environmental interactions gives an advantage to non-favored minor alleles.
Fixation probability, the probability that the frequency of a newly arising mutation in a population will eventually reach unity, is a fundamental quantity in evolutionary genetics. Here we use a number of models (several versions of the Moran model and the haploid Wright-Fisher model) to examine fixation probabilities for a constant size population where the fitness is a random function of both allelic state and spatial position, despite neither allele being favored on average. The concept of fitness varying with respect to both genotype and environment is important in models of cancer initiation and progression, bacterial dynamics, and drug resistance. Under our model spatial heterogeneity redefines the notion of neutrality for a newly arising mutation, as such mutations fix at a higher rate than that predicted under neutrality. The increased fixation probability appears to be due to rare alleles having an advantage. The magnitude of this effect can be large, and is an increasing function of the spatial variance and skew in fitness. The effect is largest when the fitness values of the mutants and wild types are anti-correlated across environments. We discuss results for both a spatial ring geometry of cells (such as that of a colonic crypt), a 2D lattice and a mass-action (complete graph) arrangement
Effect of Vitamin D Therapy on Sexual Function in Women with Sexual Dysfunction and Vitamin D Deficiency: A Randomized, Double-Blind, Placebo Controlled Clinical Trial
PURPOSE: We investigated the effect of vitamin D therapy on sexual function in women with low vitamin D levels and sexual dysfunction. MATERIALS AND METHODS: We performed this randomized, double-blind, placebo controlled trial in women 18 to 45 years old with sexual dysfunction, defined as a FSFI (Female Sexual Functioning Index) score less than 26.55, and serum 25OHD less than 30 ng/ml. Participants received an intramuscular injection of 300,000 IU cholecalciferol or a placebo at baseline and then after 4 weeks. Sexual function was evaluated with the FSFI at baseline, and 4 and 8 weeks. The serum level of 25OHD was measured and depression symptoms were evaluated by the BDI (Beck Depression Inventory) at baseline and 8 weeks. RESULTS: A total of 38 women in each group completed the study. Serum 25OHD levels increased only in the cholecalciferol group by a mean ± SD of 14.4 ± 3.2 ng/ml (p <0.001). The FSFI score was higher in the intervention group at study week 4 (19.6 vs 16.3, p = 0.002) and week 8 (25.0 vs 17.1, p <0.001). The BDI score was significantly decreased only in the cholecalciferol group by a mean of -21.0 ± 12.3 (p <0.001). The effect of treatment on sexual function was independent of its effect on depression symptoms. CONCLUSIONS: Vitamin D therapy in women with sexual dysfunction and vitamin D deficiency can improve sexual function. This effect does not seem to be mediated by an improvement in depression symptoms