The right choice of moment for anisotropic fluid dynamics

We study anisotropic fluid dynamics derived from the Boltzmann equation based on a particular choice for the anisotropic distribution function within a boost-invariant expansion of the fluid in one spatial dimension. In order to close the conservation equations we need to choose an additional moment of the Boltzmann equation. We discuss the influence of this choice of closure on the time evolution of fluid-dynamical variables and search for the best agreement to the solution of the Boltzmann equation in the relaxation-time approximation.Comment: 4 pages, 4 figures, proceedings for Quark Matter 201

Equivariance, BRST and Superspace

The structure of equivariant cohomology in non-abelian localization formulas and topological field theories is discussed. Equivariance is formulated in terms of a nilpotent BRST symmetry, and another nilpotent operator which restricts the BRST cohomology onto the equivariant, or basic sector. A superfield formulation is presented and connections to reducible (BFV) quantization of topological Yang-Mills theory are discussed.Comment: (24 pages, report UU-ITP and HU-TFT-93-65

Stresses in the vicinity of an un-reinforced mitre intersection: an experimental and finite element comparison

The experimental investigation reported provides elastic stresses in the vicinity of the unreinforced intersection of a single 90° mitred bend, subjected to an in-plane bending moment. The specimen was extensively strain gauged on the outer surface. A small number of rosettes were also laid on the inside surface close to the welded intersection. The procedures used for the successful installation of the inside surface gauges are discussed. In the experiment, consideration was also given to deflections and rotations. Satisfactory comparisons with adaptive-p thin-shell finite element results were obtained in general and differences are explained in terms of the known experimental variables and finite element approximations. The nature of the stresses at such intersections is discussed and various methods of obtaining fatigue 'hot-spot' stresses are considered

Market implications of FMD epidemics in the Finnish pig sector: Does market structure matter?

This paper examines the role of market coordination and market distortions caused by a hypothetical FMD outbreak in the Finnish pig sector. By using stochastic dynamic programming, it simulates the consequences of two outbreak scenarios (large vs. small) under two distinct market regimes (competitive market vs. monopoly in the domestic supply). Simulated losses depend on the magnitude of outbreak and expected duration of possible turndown of meat exports, whereas market regime has a limited impact.Foreign trade, livestock epidemics, dynamic programming, Livestock Production/Industries,

On non-singular renewal kernels with an application to a semigroup of transition kernels

AbstractWe study the non-singularity and limit properties of the renewal kernel R=∑K∗n associated with a positive convolution kernel K(x,dy×dt) defined on a general measurable space (E, E). The principal tool is the use of embedded renewal measures. As an application we consider continuous parameter semigroups (Rt(x,dy);t⩾0) of transition kernels on (E, E)

The Impacts of Alternative Policy Scenarios on Multifunctionality

This paper provides first results of the sector model approach to analyze the effects of alternative policy scenarios on the multifunctional role of Finnish agriculture. In terms of environmental non-commodity outputs we focus on nutrient runoffs, landscape diversity and biodiversity. As regards to socio-economic outputs our focus is on direct and indirect agricultural labour force. The results suggest that while partial de-coupling agricultural supports from production is not likely to result in any drastic decline of agricultural production the amount of green fallow will increase considerably. As a result, the agricultural land will become biologically richer. The agricultural labour force is likely to decrease substantially irrespective of agricultural policy.agricultural policy, multifunctionality, sector model, Agricultural and Food Policy, Q18, Q21,

Elliptic flow in nuclear collisions at the Large Hadron Collider

We use perfect-fluid hydrodynamical model to predict the elliptic flow coefficients in Pb + Pb collisions at the Large Hadron Collider (LHC). The initial state for the hydrodynamical calculation for central $A + A$ collisions is obtained from the perturbative QCD + saturation (EKRT) model. The centrality dependence of the initial state is modeled by the optical Glauber model. We show that the baseline results obtained from the framework are in good agreement with the data from the Relativistic Heavy Ion Collider (RHIC), and show predictions for the $p_T$ spectra and elliptic flow of pions in Pb + Pb collisions at the LHC. Also mass and multiplicity effects are discussed.Comment: 11 pages, 10 figure

Quantum Field Theory and Differential Geometry

We introduce the historical development and physical idea behind topological Yang-Mills theory and explain how a physical framework describing subatomic physics can be used as a tool to study differential geometry. Further, we emphasize that this phenomenon demonstrates that the interrelation between physics and mathematics have come into a new stage.Comment: 29 pages, enlarged version, some typewritten mistakes have been corrected, the geometric descrition to BRST symmetry, the chain of descent equations and its application in TYM as well as an introduction to R-symmetry have been added, as required by mathematicia