A Numerical Evaluation of the Stochastic Completeness of the Kinetic Coagulation Equation

The stochastic completeness of the kinetic coagulation equation depends on the extent of correlations between particle properties. Such correlations are induced by the coalescence process that causes spatial inhomogeneities in the number concentration of the particles, and are particularly strong in poorly mixed suspensions. A Monte Carlo simulation of the coalescence process is used to evaluate the suitability of the kinetic coagulation equation to simulate the coalescence process using Brownian diffusion, fluid shear and differential sedimentation collision kernels. It is demonstrated that the outcome of the kinetic equation matches well the true stochastic averages, unless the number concentration of particles involved is very small. In that case, the discrepancies between the two approaches are substantial in the large end of the particle size spectrum

GPs’ implicit prioritization through clinical choices – evidence from three national health services

We present results from an extensive discrete choice experiment, which was conducted in three countries (Norway, Scotland, and England) with the aim of disclosing stated prescription behaviour in different decision making contexts and across different cost containment cultures. We show that GPs in all countries respond to information about societal costs, benefits and effectiveness, and that they make trade-offs between them. The UK GPs have higher willingness to accept costs when they can prescribe medicines that are cheaper or more preferred by the patient, while Norwegian GPs tend to have higher willingness to accept costs for attributes regarding effectiveness or the doctors’ experience. In general there is a substantial amount of heterogeneity also within each country. We discuss the results from the DCE in the light of the GPs’ two conflicting agency roles and what we know about the incentive structures and cultures in the different countries

Effective Photodissociation Cross Sections for Molecular Oxygen and Nitric Oxide in the Schumann-Runge Bands

Simple polynomial representations of the altitude and zenith angle dependence of effective photodissociation cross sections for molecular oxygen and nitric oxide in the Schumann-Runge band region are presented. Longward of ∼202 nm, the atmosphere is optically thin and the effective cross sections are well correlated with local temperature. Atmospheric transmission values and O2 and NO photodissociation rates calculated using the parameterized effective cross sections are in good agreement with the results of the high spectral resolution computations of Frederick and Hudson. The effective cross section approach allows the use of different solar spectra and avoids the assumption of previous work that ray paths at different solar zenith angles, but with the same O2 absorbing column, have the same opacity and dissociation rates. The errors resulting from this assumption can exceed 20% at optical depths greater than 2

Post-collision Interactions in the Auger Decay of the Ar L-shell

The photoionization cross sections for Ar+ through Ar4+, produced by the Auger decay of a 2p hole in argon, have been measured between 242 eV and 253 eV by the use of synchrotron radiation. The high resolution of the monochromator has allowed a detailed study of the postcollision interactions that occur in this spectral region. The concept of photoelectron recapture by Ar2+ to produce the Ar+ continuum is studied. The relative values of the quantum-mechanical calculations of the photoelectron recapture probability are shown to be in excellent agreement with the present data. The magnitude and shape of the Ar2+ continuum has been explained on the basis that about 67% of the recaptured photoelectrons produce excited states of Ar+ which subsequently reemit the electrons by autoionization

On the inflationary flow equations

I explore properties of the inflationary flow equations. I show that the flow equations do not correspond directly to inflationary dynamics. Nevertheless, they can be used as a rather complicated algorithm for generating inflationary models. I demonstrate that the flow equations can be solved analytically and give a closed form solution for the potentials to which flow equation solutions correspond. I end by considering some simpler algorithms for generating stochastic sets of slow-roll inflationary models for confrontation with observational data.Comment: 4 pages RevTeX4 file. Corrected typos in Eqs 11 and 13. Supersedes journal versio

Directional–seasonal extreme value analysis of North Sea storm conditions

Design and re-analysis of offshore structures requires the joint estimation of extreme values for a set of environmental variables, representing so-called long-term and short-term characteristics of the environment, subject to sources of systematic variation including directionality and seasonality. Estimation is complicated by numerous sources of uncertainty, typically including limited sample size and the specification of a number of analysis parameters (such as thresholds for peaks over threshold analysis). In this work, we present a model to estimate joint extremal characteristics of the ocean environment incorporating non-stationary marginal and conditional extreme value analysis, and thorough uncertainty quantification, within a Bayesian framework. The model is used to quantify the joint directional–seasonal structure of extremes waves, winds and currents at a location in the Danish sector of the North Sea

Entropic Upper Bound on Gravitational Binding Energy

We prove that the gravitational binding energy {\Omega} of a self gravitating system described by a mass density distribution {\rho}(x) admits an upper bound B[{\rho}(x)] given by a simple function of an appropriate, non-additive Tsallis' power-law entropic functional Sq evaluated on the density {\rho}. The density distributions that saturate the entropic bound have the form of isotropic q-Gaussian distributions. These maximizer distributions correspond to the Plummer density profile, well known in astrophysics. A heuristic scaling argument is advanced suggesting that the entropic bound B[{\rho}(x)] is unique, in the sense that it is unlikely that exhaustive entropic upper bounds not based on the alluded Sq entropic measure exit. The present findings provide a new link between the physics of self gravitating systems, on the one hand, and the statistical formalism associated with non-additive, power-law entropic measures, on the other hand

Bounds on the cosmological abundance of primordial black holes from diffuse sky brightness: single mass spectra

We constrain the mass abundance of unclustered primordial black holes (PBHs), formed with a simple mass distribution and subject to the Hawking evaporation and particle absorption from the environment. Since the radiative flux is proportional to the numerical density, an upper bound is obtained by comparing the calculated and observed diffuse background values, (similarly to the Olbers paradox in which point sources are considered) for finite bandwidths. For a significative range of formation redshifts the bounds are better than several values obtained by other arguments $\Omega_{pbh} \leq 10^{-10}$; and they apply to PBHs which are evaporating today.Comment: 20 pages, 5 figures, to appear in PR