Measurements of αs\alpha_s from event shapes and the four-jet rate

New results from measurements of the strong coupling constant $\alpha_s(M_Z)$ at LEP are presented. In particular, a new LEP combination of results based on event-shape variables has become available, where a new method for the estimation of the theoretical uncertainty has been implemented. Furthermore, two other analyses are quoted, based on power corrections and the four-jet rate.Comment: Talk presented at the 31st International Conference on High Energy Physics, Amsterdam, 24-31 July 200

Systems of symplectic forms on four-manifolds

We study almost Hermitian 4-manifolds with holonomy algebra, for the canonical Hermitian connection, of dimension at most one. We show how Riemannian 4-manifolds admitting five orthonormal symplectic forms fit therein and classify them. In this set-up we also fully describe almost Kaehler 4-manifolds.Comment: Final version, to appear in Annali di SNS.added thm. 5.

Complex homothetic foliations on K\"ahler manifolds

We obtain a local classification of complex homothetic foliations on Kaehler manifolds by complex curves. This is used to construct almost Kaehler, Ricci-flat metrics subject to additional curvature properties.Comment: Final version, up to typos. To appear in BLM

Photonic tuning of quasi-particle decay in a superfluid

We show that the damping rate of elementary excitations of hybrid systems close to a phase transition can undergo a remarkable resonance like enhancement before mode softening takes place. In particular, we consider the friction of a collective density wave in a homogeneous superfluid of weakly interacting bosonic atoms coupled to the electromagnetic field of a single mode optical resonator. Here the Beliaev damping can thus be controlled by an external laser drive and be enhanced by several orders of magnitude

Private Sector Investment in Agricultural Research in Pakistan

Private sector investment in agricultural research in Pakistan, although growing in importance, is limited at present and with a few exceptions, has not had a significant impact on agricultural production and productivity. The publicly funded agricultural research system has made the major contribution to increases in production and productivity growth. However the impressive gains of the past cannot be achieved with the current underfunded public research system which makes it all the more important for private sector investment in agricultural research to achieve its full potential in areas of its comparative advantage. This paper identifies the magnitude of private sector agricultural research investment in Pakistan and discusses some of the current policy constraints that hamper its scope. Information was gathered through informal and formal surveys of multinational and national firms conducting agricultural research in Pakistan in the areas of inputs and product processing. Although private sector investment in agricultural research has more than doubled in the past ten years, uncertainty persists surrounding privatisation issues, unresolved intellectual property rights regulation, and the enforcement of seed certification and truth-in-labelling rules and regulations.

Ordering variable for parton showers

The parton splittings in a parton shower are ordered according to an ordering variable, for example the transverse momentum of the daughter partons relative to the direction of the mother, the virtuality of the splitting, or the angle between the daughter partons. We analyze the choice of the ordering variable and conclude that one particular choice has the advantage of factoring softer splittings from harder splittings graph by graph in a physical gauge.Comment: 28 pages, 5 figure