710 research outputs found
Faster Algorithms for Weighted Recursive State Machines
Pushdown systems (PDSs) and recursive state machines (RSMs), which are
linearly equivalent, are standard models for interprocedural analysis. Yet RSMs
are more convenient as they (a) explicitly model function calls and returns,
and (b) specify many natural parameters for algorithmic analysis, e.g., the
number of entries and exits. We consider a general framework where RSM
transitions are labeled from a semiring and path properties are algebraic with
semiring operations, which can model, e.g., interprocedural reachability and
dataflow analysis problems.
Our main contributions are new algorithms for several fundamental problems.
As compared to a direct translation of RSMs to PDSs and the best-known existing
bounds of PDSs, our analysis algorithm improves the complexity for
finite-height semirings (that subsumes reachability and standard dataflow
properties). We further consider the problem of extracting distance values from
the representation structures computed by our algorithm, and give efficient
algorithms that distinguish the complexity of a one-time preprocessing from the
complexity of each individual query. Another advantage of our algorithm is that
our improvements carry over to the concurrent setting, where we improve the
best-known complexity for the context-bounded analysis of concurrent RSMs.
Finally, we provide a prototype implementation that gives a significant
speed-up on several benchmarks from the SLAM/SDV project
A modern Fizeau experiment for education and outreach purposes
On the occasion of the laser's 50th anniversary, we performed a modern Fizeau
experiment, measuring the speed of light with a laser beam passing over the
city centre of Marseille. For a round trip distance of almost five kilometers,
the measurement has reached an uncertainty of about 10, mainly due to
atmospheric fluctuations. We present the experimental and pedagogical
challenges of this brilliant outreach experiment.Comment: accepted by Eur J Phys in november 201
Feshbach spectroscopy and scattering properties of ultracold Li+Na mixtures
We have observed 26 interspecies Feshbach resonances at fields up to 2050 G
in ultracold Li+Na mixtures for different spin-state combinations.
Applying the asymptotic bound-state model to assign the resonances, we have
found that most resonances have d-wave character. This analysis serves as
guidance for a coupled-channel calculation, which uses modified interaction
potentials to describe the positions of the Feshbach resonances well within the
experimental uncertainty and to calculate their widths. The scattering length
derived from the improved interaction potentials is experimentally confirmed
and deviates from previously reported values in sign and magnitude. We give
prospects for Li+Na and predict broad Feshbach resonances suitable
for tuning.Comment: 8 pages, 4 figures, version as published in PR
Feshbach spectroscopy and analysis of the interaction potentials of ultracold sodium
We have studied magnetic Feshbach resonances in an ultracold sample of Na
prepared in the absolute hyperfine ground state. We report on the observation
of three s-, eight d-, and three g-wave Feshbach resonances, including a more
precise determination of two known s-wave resonances, and one s-wave resonance
at a magnetic field exceeding 200mT. Using a coupled-channels calculation we
have improved the sodium ground-state potentials by taking into account these
new experimental data, and derived values for the scattering lengths. In
addition, a description of the molecular states leading to the Feshbach
resonances in terms of the asymptotic-bound-state model is presented.Comment: 11 pages, 4 figure
Prognostic significance of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 in primary breast cancer.
The uPA-mediated pathway of plasminogen activation is central to cancer metastasis. Whether uPA and PAI-1 are related to local recurrence, metastatic spread or both is not clear. We present a retrospective study of 429 primary breast cancer patients with a median follow-up of 5.1 years, in which the levels of uPA and PAI-1 in tumour extracts were analysed by means of an enzyme-linked immunosorbent assay. The median values of uPA and PAI-1, which were used as cut-off points, were 4.5 and 11.1 ng mg(-1) protein respectively. The levels of uPA and PAI-1 were correlated with tumour size, degree of anaplasia, steroid receptor status and number of positive nodes. Patients with high content of either uPA or PAI-1 had increased risk of relapse and death. We demonstrated an independent ability of PAI-1 to predict distant metastasis (relative risk 1.7, confidence limits 1.22 and 2.46) and that neither uPA nor PAI-1 provided any information regarding local recurrence
Observation of an Efimov resonance in an ultracold mixture of atoms and weakly bound dimers
We discuss our recent observation of an atom-dimer Efimov resonance in an
ultracold mixture of Cs atoms and Cs_2 Feshbach molecules [Nature Phys. 5, 227
(2009)]. We review our experimental procedure and present additional data
involving a non-universal g-wave dimer state, to contrast our previous results
on the universal s-wave dimer. We resolve a seeming discrepancy when
quantitatively comparing our experimental findings with theoretical results
from effective field theory.Comment: Conference Proceeding ICPEAC 2009 Kalamazoo, to appear in Journal of
Physics: Conference Serie
Observation of an Efimov resonance in an ultracold mixture of atoms and weakly bound dimers
We discuss our recent observation of an atom-dimer Efimov resonance in an
ultracold mixture of Cs atoms and Cs_2 Feshbach molecules [Nature Phys. 5, 227
(2009)]. We review our experimental procedure and present additional data
involving a non-universal g-wave dimer state, to contrast our previous results
on the universal s-wave dimer. We resolve a seeming discrepancy when
quantitatively comparing our experimental findings with theoretical results
from effective field theory.Comment: Conference Proceeding ICPEAC 2009 Kalamazoo, to appear in Journal of
Physics: Conference Serie
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