12,203 research outputs found
A Development Environment for Visual Physics Analysis
The Visual Physics Analysis (VISPA) project integrates different aspects of
physics analyses into a graphical development environment. It addresses the
typical development cycle of (re-)designing, executing and verifying an
analysis. The project provides an extendable plug-in mechanism and includes
plug-ins for designing the analysis flow, for running the analysis on batch
systems, and for browsing the data content. The corresponding plug-ins are
based on an object-oriented toolkit for modular data analysis. We introduce the
main concepts of the project, describe the technical realization and
demonstrate the functionality in example applications
SECURITY OF RUNNING OF COMPETETIVE COURSE IN ALPINE SKIING ACCORDING TO ITS GEOMETRY OF SETTING
In alpine ski disciplines there are plenty of incidents. Sometimes up to 40 % of competitors do not finish the run. The reasons are wrong preparation of skiers and wrong tactics of running. But there are also some errors in setting of gates of a course. The aim of this paper is to present some examples of those errors. One of them is a long intergate distances with small angles of deviation where skier achieves high velocity and just after that a big angle of deviation of a course with small intergate distance. The other is positioning of one gate above a downcast and the other just below a downcast. In Kvitfjel 2007 up to 10 skiers ran off the track in such a configuration
KINEMATICS OF TACTICS IN THE MEN'S 1500 M FREESTYLE SWIMMING FINAL AT THE BEIJING 2008 OLYMPIC GAMES
The purpose of this study was to obtain a knowledge on tactics of long distance swimming at the highest professional level. Eight swimmers - men, finalists of 1500 m distance of freestyle of the Beijing 2008 Olympic Games were investigated. The distribution of velocity of swimming for the entire distance based on 50 m segments was analyzed. Partial, halves and tierces velocities, velocity indexes and linear regression equations were calculated. It was revealed that better swimmers (placed 1 – 4) had their distribution of swimming as ascending line and with very small difference between segmental velocities and that of the entire distance, while the rest of swimmers had descending velocity line and higher dispersion of partial values
Generation of Pure-State Single-Photon Wavepackets by Conditional Preparation Based on Spontaneous Parametric Downconversion
We study the conditional preparation of single photons based on parametric
downconversion, where the detection of one photon from a given pair heralds the
existence of a single photon in the conjugate mode. We derive conditions on the
modal characteristics of the photon pairs, which ensure that the conditionally
prepared single photons are quantum-mechanically pure. We propose specific
experimental techniques that yield photon pairs ideally suited for
single-photon conditional preparation.Comment: 14 pages, 6 figure
Collective motion of active Brownian particles in one dimension
We analyze a model of active Brownian particles with non-linear friction and
velocity coupling in one spatial dimension. The model exhibits two modes of
motion observed in biological swarms: A disordered phase with vanishing mean
velocity and an ordered phase with finite mean velocity. Starting from the
microscopic Langevin equations, we derive mean-field equations of the
collective dynamics. We identify the fixed points of the mean-field equations
corresponding to the two modes and analyze their stability with respect to the
model parameters. Finally, we compare our analytical findings with numerical
simulations of the microscopic model.Comment: submitted to Eur. Phys J. Special Topic
When it Pays to Rush: Interpreting Morphogen Gradients Prior to Steady-State
During development, morphogen gradients precisely determine the position of
gene expression boundaries despite the inevitable presence of fluctuations.
Recent experiments suggest that some morphogen gradients may be interpreted
prior to reaching steady-state. Theoretical work has predicted that such
systems will be more robust to embryo-to-embryo fluctuations. By analysing two
experimentally motivated models of morphogen gradient formation, we investigate
the positional precision of gene expression boundaries determined by
pre-steady-state morphogen gradients in the presence of embryo-to-embryo
fluctuations, internal biochemical noise and variations in the timing of
morphogen measurement. Morphogens that are direct transcription factors are
found to be particularly sensitive to internal noise when interpreted prior to
steady-state, disadvantaging early measurement, even in the presence of large
embryo-to-embryo fluctuations. Morphogens interpreted by cell-surface receptors
can be measured prior to steady-state without significant decrease in
positional precision provided fluctuations in the timing of measurement are
small. Applying our results to experiment, we predict that Bicoid, a
transcription factor morphogen in Drosophila, is unlikely to be interpreted
prior to reaching steady-state. We also predict that Activin in Xenopus and
Nodal in zebrafish, morphogens interpreted by cell-surface receptors, can be
decoded in pre-steady-state.Comment: 18 pages, 3 figure
Qualification Procedures of the CMS Pixel Barrel Modules
The CMS pixel barrel system will consist of three layers built of about 800
modules. One module contains 66560 readout channels and the full pixel barrel
system about 48 million channels. It is mandatory to test each channel for
functionality, noise level, trimming mechanism, and bump bonding quality.
Different methods to determine the bump bonding yield with electrical
measurements have been developed. Measurements of several operational
parameters are also included in the qualification procedure. Among them are
pixel noise, gains and pedestals. Test and qualification procedures of the
pixel barrel modules are described and some results are presented.Comment: 7 Pages, 7 Figures. Contribution to Pixel 2005, September 5-8, 2005,
Bonn, Germna
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