Microbial demethylation of dimethylsulfoniopropionate and methylthiopropionate

As discussed in chapter 1 , there is an increased interest in the production of certain natural sulfur-containing flavor compounds or flavor precursors. Production of natural flavors is becoming increasingly important, because consumerts end to prefer natural compounds for health reasons. With the aid of extraction techniques it is possible to obtain flavors directly from plant material, but these methods are time consuming and expensive, because the most interesting flavors are present in only very low concentrations. A more recent method to produce flavors is based on a biotechnological approach where natural precursors, isolated mainly from plant material, can be convertedt o the desired flavor in a bioreactor with the aid of enzymes and/or microorganisms.

The Sequential Order of Procedural Instructions: Some Formal Methods for Designers of Flow Charts

Document designers who present procedural instructions can choose several formats: prose, table, logical tree, or flow chart. In all cases, however, it is essential that the instructions are ordered in a way that allows users to reach the outcome in as little time as possible. In this article two formal methods are discussed that help determine which order is most efficient. The first method is based on the selection principle. The second method is based on the principle of the average least effort

The pitch rather than the pit: investor inattention during FIFA world cup matches

At the 2010 FIFA World Cup in South Africa, many soccer matches were played during stock market trading hours, providing us with a natural experiment to analyze fluctuations in investor attention. Using minute-by-minute trading data for fifteen international stock exchanges, we present three key findings. First, when the national team was playing, the number of trades dropped by 45%, while volumes were 55% lower. Second, market activity was influenced by match events. For instance, a goal caused an additional drop in trading activity by 5%. The magnitude of this reduction resembles what is observed during lunchtime, and as such might not be indicative for shifts in attention. However, our third finding is that the comovement between national and global stock market returns decreased by over 20% during World Cup matches, whereas no comparable decoupling can be found during lunchtime. We conclude that stock markets were following developments on the soccer pitch rather than in the trading pit, leading to a changed price formation process. JEL Classification: G12, G14, G15.Investor inattention, stock markets, trading volume, high-frequency data, soccer.

FPT is Characterized by Useful Obstruction Sets

Many graph problems were first shown to be fixed-parameter tractable using the results of Robertson and Seymour on graph minors. We show that the combination of finite, computable, obstruction sets and efficient order tests is not just one way of obtaining strongly uniform FPT algorithms, but that all of FPT may be captured in this way. Our new characterization of FPT has a strong connection to the theory of kernelization, as we prove that problems with polynomial kernels can be characterized by obstruction sets whose elements have polynomial size. Consequently we investigate the interplay between the sizes of problem kernels and the sizes of the elements of such obstruction sets, obtaining several examples of how results in one area yield new insights in the other. We show how exponential-size minor-minimal obstructions for pathwidth k form the crucial ingredient in a novel OR-cross-composition for k-Pathwidth, complementing the trivial AND-composition that is known for this problem. In the other direction, we show that OR-cross-compositions into a parameterized problem can be used to rule out the existence of efficiently generated quasi-orders on its instances that characterize the NO-instances by polynomial-size obstructions.Comment: Extended abstract with appendix, as accepted to WG 201

Understanding nominal GNP targeting

Gross national product

Effects of non-perturbatively improved dynamical fermions in UKQCD simulations

We present results for QCD with 2 degenerate flavours of quark using a non-perturbatively improved action on a lattice volume of $16^3\times32$ where the bare gauge coupling and bare dynamical quark mass have been chosen to maintain a fixed physical lattice spacing and volume (1.71 fm). By comparing measurements from these matched ensembles, including quenched ones, we find evidence of dynamical quark effects on the short distance static potential, the scalar glueball mass and the topological susceptibility. There is little evidence of effects on the light hadron spectrum over the range of quark masses studied ($m_{\pi}/m_{\rho}\geq 0.60$).Comment: Lattice 2000 (Spectrum and quark masses), 4 pages, 5 figure