The non-perturbative O(a)-improved action for dynamical Wilson fermions

We compute the improvement coefficient $c_{sw}$ that multiplies the Sheikholeslami-Wohlert term as a function of the bare gauge coupling for two flavour QCD. We discuss several aspects concerning simulations with improved dynamical Wilson fermions.Comment: Latex file, 2 figures, 6 pages, talk given by K.J. at the International Symposium on Lattice Field Theory, 21-27 July 1997, Edinburgh, Scotlan

A Polynomial Hybrid Monte Carlo Algorithm

We present a simulation algorithm for dynamical fermions that combines the multiboson technique with the Hybrid Monte Carlo algorithm. We find that the algorithm gives a substantial gain over the standard methods in practical simulations. We point out the ability of the algorithm to treat fermion zeromodes in a clean and controllable manner.Comment: Latex, 1 figure, 12 page

Study of Liapunov Exponents and the Reversibility of Molecular Dynamics Algorithms

We study the question of lack of reversibility and the chaotic nature of the equations of motion in numerical simulations of lattice QCD.Comment: latex file with 3 pages, 1 figure. Talk presented at Lattice'96 by C. Li

A Gauge-Fixing Action for Lattice Gauge Theories

We present a lattice gauge-fixing action $S_{gf}$ with the following properties: (a) $S_{gf}$ is proportional to the trace of $(\sum_\mu \partial_\mu A_\mu)^2$, plus irrelevant terms of dimension six and higher; (b) $S_{gf}$ has a unique absolute minimum at $U_{x,\mu}=I$. Noting that the gauge-fixed action is not BRST invariant on the lattice, we discuss some important aspects of the phase diagram.Comment: 13 pages, Latex, improved presentation, no change in result

Stochastic equations for a self-regulating gene

Expression of cellular genes is regulated by binding of transcription factors to their promoter, either activating or inhibiting transcription of a gene. Particularly interesting is the case when the expressed protein regulates its own transcription. In this paper the features of this self-regulating process are investigated. In the here presented model the gene can be in two states. Either a protein is bound to its promoter or not. The steady state distributions of protein during and at the end of both states are analyzed. Moreover a powerful numerical method based on the corresponding master equation to compute the protein distribution in the steady state is presented and compared to an already existing method. Additionally the special case of self-regulation, in which protein can only be produced, if one of these proteins is bound to the promoter region, is analyzed. Furthermore a self-regulating gene is compared to a similar gene, which also has two states and produces the same amount of proteins but is not regulated by its protein-product

On Competition and the Strategic Management of Intellectual Property in Oligopoly

An innovative firm with private information about its indivisible process innovation chooses strategically whether to apply for a patent with probabilistic validity or rely on secrecy. By doing so, the firm manages its rivals’ beliefs about the size of the innovation, and affects the incentives in the product market. A Cournot competitor tends to patent big innovations, and keep small innovations secret, while a Bertrand competitor adopts the reverse strategy. Increasing the number of firms gives a greater (smaller) patenting incentive for Cournot (Bertrand) competitors. Increasing the degree of product substitutability increases the incentives to patent the innovation

Weakening Assumptions for Deterministic Subexponential Time Non-Singular Matrix Completion

In (Kabanets, Impagliazzo, 2004) it is shown how to decide the circuit polynomial identity testing problem (CPIT) in deterministic subexponential time, assuming hardness of some explicit multilinear polynomial family for arithmetical circuits. In this paper, a special case of CPIT is considered, namely low-degree non-singular matrix completion (NSMC). For this subclass of problems it is shown how to obtain the same deterministic time bound, using a weaker assumption in terms of determinantal complexity. Hardness-randomness tradeoffs will also be shown in the converse direction, in an effort to make progress on Valiant's VP versus VNP problem. To separate VP and VNP, it is known to be sufficient to prove that the determinantal complexity of the m-by-m permanent is $m^{\omega(\log m)}$. In this paper it is shown, for an appropriate notion of explicitness, that the existence of an explicit multilinear polynomial family with determinantal complexity m^{\omega(\log m)}$is equivalent to the existence of an efficiently computable generator$G_n$for multilinear NSMC with seed length$O(n^{1/\sqrt{\log n}})$. The latter is a combinatorial object that provides an efficient deterministic black-box algorithm for NSMC. ``Multilinear NSMC'' indicates that$G_n$only has to work for matrices$M(x)$of$poly(n)$size in$n$variables, for which$det(M(x))$ is a multilinear polynomial

The Civic and Community Engagement of Religiously Active Americans

Presents survey findings about attitudes of those who are active in religious or spiritual groups toward people, their communities, their ability to make an impact on their communities, and the Internet, as well as their involvement with other groups

Enron versus EUSES: A Comparison of Two Spreadsheet Corpora

Spreadsheets are widely used within companies and often form the basis for business decisions. Numerous cases are known where incorrect information in spreadsheets has lead to incorrect decisions. Such cases underline the relevance of research on the professional use of spreadsheets. Recently a new dataset became available for research, containing over 15.000 business spreadsheets that were extracted from the Enron E-mail Archive. With this dataset, we 1) aim to obtain a thorough understanding of the characteristics of spreadsheets used within companies, and 2) compare the characteristics of the Enron spreadsheets with the EUSES corpus which is the existing state of the art set of spreadsheets that is frequently used in spreadsheet studies. Our analysis shows that 1) the majority of spreadsheets are not large in terms of worksheets and formulas, do not have a high degree of coupling, and their formulas are relatively simple; 2) the spreadsheets from the EUSES corpus are, with respect to the measured characteristics, quite similar to the Enron spreadsheets.Comment: In Proceedings of the 2nd Workshop on Software Engineering Methods in Spreadsheet

Resolution studies with the DATURA beam telescope

Detailed studies of the resolution of a EUDET-type beam telescope are carried out using the DATURA beam telescope as an example. The EUDET-type beam telescopes make use of CMOS MIMOSA 26 pixel detectors for particle tracking allowing for precise characterisation of particle sensing devices. A profound understanding of the performance of the beam telescope as a whole is obtained by a detailed characterisation of the sensors themselves. The differential intrinsic resolution as measured in a MIMOSA 26 sensor is extracted using an iterative pull method and various quantities that depend on the size of the cluster are discussed: the residual distribution, the intra-pixel residual-width distribution and the intra-pixel density distribution of track incident positions