Search results for "Approx"
showing 10 items of 922 documents
Experimental study of $^{100}$Tc $\beta$ decay with total absorption $\gamma$-ray spectroscopy
2017
International audience; The β decay of Tc100 has been studied by using the total absorption γ-ray spectroscopy technique at the Ion Guide Isotope Separator On-Line facility in Jyväskylä. In this work the new Decay Total Absorption γ-ray Spectrometer in coincidence with a cylindrical plastic β detector has been employed. The β intensity to the ground state obtained from the analysis is in good agreement with previous high-resolution measurements. However, differences in the feeding to the first-excited state as well as weak feeding to a new level at high excitation energy have been deduced from this experiment. Theoretical calculations performed in the quasiparticle random-phase approximatio…
Measurement of the spin-dependent structure function g1(x) of the deuteron
1993
We report on the first measurement of the spin-dependent structure function g1d of the deuteron in the deep inelastic scattering of polarised muons off polarised deuterons, in the kinematical range 0.006<x<0.6, 1 GeV2<Q2<30 GeV2. The first moment, Γ1d=sh{phonetic}01 g1d dx=0.023±0.020 (stat.) ± 0.015 (syst.), is smaller than the prediction of the Ellis-Jaffe sum rules. Using earlier measurements of g1p, we infer the first moment of the spin-dependent neutron structure function g1n. The difference Γ1p-Γ1n=0.20 ±0.05 (stat.) ± 0.04 (syst.) agrees with the prediction of the Bjorken sum rule, Γ1p-Γ1n=0.191 ±0.002.
Characterization of the Magnetic Induction Field produced by Secondary Substations
2014
The aim of this paper is to develop a methodology for measuring the magnetic field distribution around the prefabricated secondary substations in vibrated reinforced concrete, as well as the definition of a methodology to determining the maximum value of magnetic induction produced by the substations in correspondence to nominal current of the transformer. As proposed has been developed in conformity with laws and standards and can be applied to active and passive secondary substations. The experimental validation of the proposed methodology, carried out by a measurements campaign whose results are reported, confirms the validity and returns a versatile and simple tool for the verification …
Inferring Learning Strategies from Cultural Frequency Data
2015
Social learning has been identified as one of the fundamentals of culture and therefore the understanding of why and how individuals use social information presents one of the big questions in cultural evolution. To date much of the theoretical work on social learning has been done in isolation of data. Evolutionary models often provide important insight into which social learning strategies are expected to have evolved but cannot tell us which strategies human populations actually use. In this chapter we explore how much information about the underlying learning strategies can be extracted by analysing the temporal occurrence or usage patterns of different cultural variants in a population…
Nonlinear Relaxation in Population Dynamics
2001
We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the i-th population and on the distribution of the population and of the local field.
Continental-scale patterns of pathogen prevalence: a case study on the corncrake
2014
Pathogen infections can represent a substantial threat to wild populations, especially those already limited in size. To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling for any potentially confounding genetic effects. Here, we report geographic variation in haemosporidian infection among European populations of corncrake. This species now occurs in fragmented populations, but there is little genetic structure and equally high levels of genetic diversity among these populations. We observed a longitudinal gradient…
An adaption mechanism for the error threshold of XCSF
2020
Learning Classifier System (LCS) is a class of rule-based learning algorithms, which combine reinforcement learning (RL) and genetic algorithm (GA) techniques to evolve a population of classifiers. The most prominent example is XCS, for which many variants have been proposed in the past, including XCSF for function approximation. Although XCSF is a promising candidate for supporting autonomy in computing systems, it still must undergo parameter optimization prior to deployment. However, in case the later deployment environment is unknown, a-priori parameter optimization is not possible, raising the need for XCSF to automatically determine suitable parameter values at run-time. One of the mo…
Electromagnetic wave propagation in non-homogeneous waveguides
2015
We investigate an electromagnetic waveguide, having several cylindrical ends. The waveguide is assumed to be empty and to have a perfectly conductive boundary. We study the electromagnetic field, excited in the waveguide in the presence of charges and currents. The field can be described as a solution of the stationary Maxwell system with conductive boundary conditions and “intrinsic” radiation conditions at infinity. We prove the problem to be well-posed. Electromagnetic waves propagation in the waveguide can be described by means of a scattering matrix. We introduce such a matrix for all values of the spectral parameter k in the waveguide continuous spectrum and study its properties. Moreove…
The Born–Oppenheimer equilibrium bond distance of GeO from millimetre- and submillimetre-wave spectra and quantum-chemical calculations
2014
The millimetre- and submillimetre-wave spectra of the five common isotopologues of (GeO)-O-16 in their electronic and vibrational ground state have been recorded in the spectral region 115-732GHz; for (GeO)-Ge-74-O-16, the rotational spectrum in the v = 1 state has been detected as well. Exploiting the high precision of the measurements, the Born-Oppenheimer breakdown parameter Delta(Ge)(01) could be determined from a Dunham analysis of the spectral data, whereas Delta(O)(01) was obtained from quantum-chemical calculations, because of the lack of high-precision measurements for the (GeO)-O-18 isotopologues. From the rotational equilibrium constant, the Born-Oppenheimer equilibrium distance …
Convergence of dynamic programming principles for the $p$-Laplacian
2018
We provide a unified strategy to show that solutions of dynamic programming principles associated to the $p$-Laplacian converge to the solution of the corresponding Dirichlet problem. Our approach includes all previously known cases for continuous and discrete dynamic programming principles, provides new results, and gives a convergence proof free of probability arguments.