Bielefeld University

About: Bielefeld University is a education organization based out in Bielefeld, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Quantum chromodynamics. The organization has 10123 authors who have published 26576 publications receiving 728250 citations. The organization is also known as: University of Bielefeld & UNIVERSITAET BIELEFELD.

Quarkonium production in hadronic collisions

Abstract: We summarize the theoretical description of charmonium and bottonium production in hadronic collisions and compare it to the available data from hadron-nucleon interactions. With the parameters of the theory established by these data, we obtain predictions for quarkonium production at RHIC and LHC energies.

Exploring trial-by-trial modulations of the Simon effect.

Abstract: The present study investigates sequential modulations of the Simon effect The Simon effect involves faster responses to spatially corresponding than to noncorresponding stimuli, even when stimulus position is irrelevant Recently, the Simon effect has been shown to decrease or to disappear after noncorresponding predecessor trials Possible explanations for these sequential modulations include (a) the gating of position-based response activation (conflict monitoring), (b) repetition or alternation effects, and (c) the interaction between feature integration (binding) processes and stimulus-response (S-R) correspondence Three experiments tested different predictions of these models by comparing Simon effects after neutral trials with those after corresponding and noncorresponding trials, respectively, and by varying the stimulus-onset asynchrony (SOA) between and within experiments Experiments 1 and 2 revealed large Simon effects after corresponding trials, intermediate Simon effects after neutral trials, and small (or no) Simon effects after noncorresponding trials Moreover, some systematic effects of S-R repetitions and S-R alternations were observed Finally, the sequential modulations were maximal at short SOAs and decreased with increasing SOA, but still occurred at an SOA of 6 seconds The results seem to exclude repetition or alternation effects as the main cause of sequential modulations of the Simon effect, but both conflict monitoring and binding may contribute to these effects

Cosmic radio dipole from NVSS and WENSS

Abstract: We use linear estimators to determine the magnitude and direction of the cosmic radio dipole from the NRAO VLA Sky Survey (NVSS) and the Westerbork Northern Sky Survey (WENSS). We show that special attention has to be given to the issues of bias due to shot noise, incomplete sky coverage and masking of the Milky Way. We compare several different estimators and show that conflicting claims in the literature can be attributed to the use of different estimators. We find that the NVSS and WENSS estimates of the cosmic radio dipole are consistent with each other and with the direction of the cosmic microwave background (CMB) dipole. We find from the NVSS a dipole amplitude of (1.8 ± 0.6) × 10-2 in direction (RA,dec) = (154° ± 19°, −2° ± 19°). This amplitude exceeds the one expected from the CMB by a factor of about 4 and is inconsistent with the assumption of a pure kinetic origin of the radio dipole at 99.6% CL.

Fast index based algorithms and software for matching position specific scoring matrices

Abstract: In biological sequence analysis, position specific scoring matrices (PSSMs) are widely used to represent sequence motifs in nucleotide as well as amino acid sequences. Searching with PSSMs in complete genomes or large sequence databases is a common, but computationally expensive task. We present a new non-heuristic algorithm, called ESAsearch, to efficiently find matches of PSSMs in large databases. Our approach preprocesses the search space, e.g., a complete genome or a set of protein sequences, and builds an enhanced suffix array that is stored on file. This allows the searching of a database with a PSSM in sublinear expected time. Since ESAsearch benefits from small alphabets, we present a variant operating on sequences recoded according to a reduced alphabet. We also address the problem of non-comparable PSSM-scores by developing a method which allows the efficient computation of a matrix similarity threshold for a PSSM, given an E-value or a p-value. Our method is based on dynamic programming and, in contrast to other methods, it employs lazy evaluation of the dynamic programming matrix. We evaluated algorithm ESAsearch with nucleotide PSSMs and with amino acid PSSMs. Compared to the best previous methods, ESAsearch shows speedups of a factor between 17 and 275 for nucleotide PSSMs, and speedups up to factor 1.8 for amino acid PSSMs. Comparisons with the most widely used programs even show speedups by a factor of at least 3.8. Alphabet reduction yields an additional speedup factor of 2 on amino acid sequences compared to results achieved with the 20 symbol standard alphabet. The lazy evaluation method is also much faster than previous methods, with speedups of a factor between 3 and 330. Our analysis of ESAsearch reveals sublinear runtime in the expected case, and linear runtime in the worst case for sequences not shorter than | | m + m - 1, where m is the length of the PSSM and a finite alphabet. In practice, ESAsearch shows superior performance over the most widely used programs, especially for DNA sequences. The new algorithm for accurate on-the-fly calculations of thresholds has the potential to replace formerly used approximation approaches. Beyond the algorithmic contributions, we provide a robust, well documented, and easy to use software package, implementing the ideas and algorithms presented in this manuscript.