590 research outputs found
Local Traffic Safety Analyzer – Improved Road Safety and Optimized Signal Control for Future Urban Intersections
Improving road safety and optimizing the traffic flow – these are major challenges at urban intersections. In particular, strengthening the needs of vulnerable road users (VRUs) such as pedestrians, cyclists and e-scooter drivers is becoming increasingly important, combined with support for automated and connected driving. In the LTSA project, a new system is being developed and implemented exactly for this purpose. The LTSA is an intelligent infrastructure system that records the movements of all road users in the vicinity of an intersection using a combination of several locally installed sensors e.g. video, radar, lidar. AI-based software processes the detected data, interprets the movement patterns of road users and continuously analyzes the current traffic situation (digital twin). Potentially dangerous situations are identified, e.g. right turning vehicles and simultaneously crossing VRUs, and warning messages can be sent to connected road users via vehicle-to-infrastructure communication (V2X). Automated vehicles can thus adapt their driving maneuvers. In addition, the collected data is applied to improve traffic light control depending on the current traffic situation, especially for VRUs. This abstract describes the LTSA system and its implementation in the German city of Potsdam. The current project state is presented and an outlook on next steps is given
New Bounds for the Integer Carath\'{e}odory Rank
Given a pointed rational -dimensional cone , we obtain new parametric
and asymptotic upper bounds for the integer Carath\'{e}odory rank
, defined as the smallest integer such that any
integer vector in can be expressed as a non-negative integer combination of
at most elements from the Hilbert basis of . Firstly, we significantly
improve previously known bounds on the integer Carath\'{e}odory rank in an
asymptotic setting, where we only consider "most" integer vectors in .
Secondly, we show that the equality , referred to as
the integer Carath\'{e}odory property, holds in arbitrary dimension for cones
that possess polyhedral representations with bimodular matrices. Furthermore,
we obtain a new upper bound on for simplicial cones
represented by -modular matrices with . Similar results are
established for cones represented by generating sets
Distances to lattice points in knapsack polyhedra
We give an optimal upper bound for the maximum norm distance from a vertex of a knapsack polyhedron to its nearest feasible lattice point. In a randomised setting, we show that the upper bound can be significantly improved on average. As a corollary, we obtain an optimal upper bound for the additive integrality gap of integer knapsack problems and show that the integrality gap of a 'typical' knapsack problem is drastically smaller than the integrality gap that occurs in a worst case scenario. We also prove that, in a generic case, the integer programming gap admits a natural optimal lower boun
The explosion mechanism of core-collapse supernovae: progress in supernova theory and experiments
The explosion of core-collapse supernova depends on a sequence of events
taking place in less than a second in a region of a few hundred kilometers at
the center of a supergiant star, after the stellar core approaches the
Chandrasekhar mass and collapses into a proto-neutron star, and before a shock
wave is launched across the stellar envelope. Theoretical efforts to understand
stellar death focus on the mechanism which transforms the collapse into an
explosion. Progress in understanding this mechanism is reviewed with particular
attention to its asymmetric character. We highlight a series of successful
studies connecting observations of supernova remnants and pulsars properties to
the theory of core-collapse using numerical simulations. The encouraging
results from first principles models in axisymmetric simulations is tempered by
new puzzles in 3D. The diversity of explosion paths and the dependence on the
pre-collapse stellar structure is stressed, as well as the need to gain a
better understanding of hydrodynamical and MHD instabilities such as SASI and
neutrino-driven convection. The shallow water analogy of shock dynamics is
presented as a comparative system where buoyancy effects are absent. This
dynamical system can be studied numerically and also experimentally with a
water fountain. The potential of this complementary research tool for supernova
theory is analyzed. We also review its potential for public outreach in science
museums.Comment: 19 pages, 6 figures, invited review accepted for publication in PAS
On the influence of Stark broadening on Si I lines in stellar atmospheres
We study the influence of Stark broadening and stratification effects on Si\i
lines in the rapidly oscillating (roAp) star 10 Aql, where the Si\i 6142.48 \AA
and 6155.13 \AA lines are asymmetrical and shifted. First we have calculated
Stark broadening parameters using the semiclassical perturbation method for
three Si\i lines: 5950.2 \AA, 6142.48 \AA and 6155.13 \AA. We revised the
synthetic sp$ calculation code taking into account both Stark width and shift
for these lines. From the comparison of our calculations with the observations
we found that Stark broadening + the stratification effect can explain
asymmetry of the Si\i 6142.48 \AA and 6155.13 \AA lines in the atmospere of
roAp star 10 Aql.Comment: Accepted to A&
Malignancy risk analysis in patients with inadequate fine needle aspiration cytology (FNAC) of the thyroid
Background
Thyroid fine needle aspiration cytology (FNAC) is the standard diagnostic modality for thyroid nodules. However, it has limitations among which is the incidence of non-diagnostic results (Thy1). Management of cases with repeatedly non-diagnostic FNAC ranges from simple observation to surgical intervention. We aim to evaluate the incidence of malignancy in non-diagnostic FNAC, and the success rate of repeated FNAC. We also aim to evaluate risk factors for malignancy in patients with non-diagnostic FNAC.
Materials and Methods
Retrospective analyses of consecutive cases with thyroid non diagnostic FNAC results were included.
Results
Out of total 1657 thyroid FNAC done during the study period, there were 264 (15.9%) non-diagnostic FNAC on the first attempt. On repeating those, the rate of a non-diagnostic result on second FNAC was 61.8% and on third FNAC was 47.2%. The overall malignancy rate in Thy1 FNAC was 4.5% (42% papillary, 42% follicular and 8% anaplastic), and the yield of malignancy decreased considerably with successive non-diagnostic FNAC. Ultrasound guidance by an experienced head neck radiologist produced the lowest non-diagnostic rate (38%) on repetition compared to US guidance by a generalist radiologist (65%) and by non US guidance (90%).
Conclusions
There is a low risk of malignancy in patients with a non-diagnostic FNAC result, commensurate to the risk of any nodule. The yield of malignancy decreased considerably with successive non-diagnostic FNAC
First Results of a New Electromechanical Controlled External Ventricular Drainage in a Porcine Model
Efficient characterization of multiple binding sites of small molecule imaging ligands on amyloid-beta, tau and alpha-synuclein
PURPOSE: There is an unmet need for compounds to detect fibrillar forms of alpha-synuclein (αSyn) and 4-repeat tau, which are critical in many neurodegenerative diseases. Here, we aim to develop an efficient surface plasmon resonance (SPR)-based assay to facilitate the characterization of small molecules that can bind these fibrils. METHODS: SPR measurements were conducted to characterize the binding properties of fluorescent ligands/compounds toward recombinant amyloid-beta (Aβ), K18-tau, full-length 2N4R-tau and αSyn fibrils. In silico modeling was performed to examine the binding pockets of ligands on αSyn fibrils. Immunofluorescence staining of postmortem brain tissue slices from Parkinson's disease patients and mouse models was performed with fluorescence ligands and specific antibodies. RESULTS: We optimized the protocol for the immobilization of Aβ, K18-tau, full-length 2N4R-tau and αSyn fibrils in a controlled aggregation state on SPR-sensor chips and for assessing their binding to ligands. The SPR results from the analysis of binding kinetics suggested the presence of at least two binding sites for all fibrils, including luminescent conjugated oligothiophenes, benzothiazole derivatives, nonfluorescent methylene blue and lansoprazole. In silico modeling studies for αSyn (6H6B) revealed four binding sites with a preference for one site on the surface. Immunofluorescence staining validated the detection of pS129-αSyn positivity in the brains of Parkinson's disease patients and αSyn preformed-fibril injected mice, 6E10-positive Aβ in arcAβ mice, and AT-8/AT-100-positivity in pR5 mice. CONCLUSION: SPR measurements of small molecules binding to Aβ, K18/full-length 2N4R-tau and αSyn fibrils suggested the existence of multiple binding sites. This approach may provide efficient characterization of compounds for neurodegenerative disease-relevant proteinopathies
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