10,868 research outputs found
The output distribution of important LULU-operators
Two procedures to compute the output distribution phi_S of certain stack
filters S (so called erosion-dilation cascades) are given. One rests on the
disjunctive normal form of S and also yields the rank selection probabilities.
The other is based on inclusion-exclusion and e.g. yields phi_S for some
important LULU-operators S. Properties of phi_S can be used to characterize
smoothing properties of S. One of the methods discussed also allows for the
calculation of the reliability polynomial of any positive Boolean function
(e.g. one derived from a connected graph).Comment: 20 pages, up to trivial differences this is the final version to be
published in Quaestiones Mathematicae 201
On the quantumness of correlations in nuclear magnetic resonance
Nuclear Magnetic Resonance (NMR) was successfully employed to test several
protocols and ideas in Quantum Information Science. In most of these
implementations the existence of entanglement was ruled out. This fact
introduced concerns and questions about the quantum nature of such bench tests.
In this article we address some issues related to the non-classical aspects of
NMR systems. We discuss some experiments where the quantum aspects of this
system are supported by quantum correlations of separable states. Such
quantumness, beyond the entanglement-separability paradigm, is revealed via a
departure between the quantum and the classical versions of information theory.
In this scenario, the concept of quantum discord seems to play an important
role. We also present an experimental implementation of an analogous of the
single-photon Mach-Zehnder interferometer employing two nuclear spins to encode
the interferometric paths. This experiment illustrate how non-classical
correlations of separable states may be used to simulate quantum dynamics. The
results obtained are completely equivalent to the optical scenario, where
entanglement (between two field modes) may be present
Endovascular repair for acute traumatic transection of the descending thoracic aorta: experience of a single centre with a 12-years follow up
Background: Most blunt aortic injuries occur in the proximal proximal descending aorta causing acute transection
of this vessel. Generally, surgical repair of the ruptured segment of aorta is associated with high rates of morbidity
and mortality and in this view endovascular treatment seems to be a valid and safer alternative. Aim of this article
is to review our experience with endovascular approach for the treatment of acute traumatic rupture of descending
thoracic aorta.
Methods: From April 2002 to November 2014, 11 patients (9 males and 2 females) were referred to our Department
with a diagnosis of acute transection of thoracic aorta. Following preoperative Computed Tomography (CT) evaluation,
thoracic endovascular aortic repair (TEVAR) with left subclavian artery coverage was performed. Follow-up consisted
clinical and instrumental (CT, Duplex ultrasound) controls at discharge, 1, 3 and 6 months and yearly thereafter.
Results: At 12-year follow up, the overall survival for the entire patients cohort was 100 %, no major or minor
neurological complications and no episode of left arm claudication occurred. Cardiovascular, respiratory and bleeding
complications, in the early period, was represented by minor, non fatal events. No stent graft failure, collapse, leak or
distal migration were detected at CT scan during the entire follow up period.
Conclusions: According to our experience, despite the small number of patient population, TEVAR procedure with
with left subclavian artery coverage, performed in emergency settings, seems to provide excellent long term results.
Trials registration: The protocol was registered at a public trials registry, www.clinicaltrials.gov (trial identifier
NCT02376998)
IC 4200: a gas-rich early-type galaxy formed via a major merger
We present the result of radio and optical observations of the S0 galaxy IC
4200. We find that the galaxy hosts 8.5 billion solar masses of HI rotating on
a ~90 deg warped disk extended out to 60 kpc from the centre of the galaxy.
Optical spectroscopy reveals a simple-stellar-population-equivalent age of 1.5
Gyr in the centre of the galaxy and V- and R-band images show stellar shells.
Ionised gas is observed within the stellar body and is kinematically decoupled
from the stars and characterised by LINER-like line ratios.We interpret these
observational results as evidence for a major merger origin of IC 4200, and
date the merger back to 1-3 Gyr ago.Comment: Accepted for publication in Astronomy & Astrophysics; 18 pages, 13
figures; the tables of Appendix C can be downloaded at
http://www.astro.rug.nl/~pserra/IC420
Fatigue Damage Estimation from Random Vibration Testing: Application to a notched specimen
Vibrations are random in a wide range of applications and they are the main cause of mechanical failure. To prevent such failure, it is necessary to evaluate the fatigue life using test or analysis techniques. For computing the severity of the damage many methods are available in literature, but the estimation damage is just an approximation. The objective of this study is to propose a numerical model, together with experimental validation, in order to estimate fatigue damage caused by random vibrations in metallic materials undergoing uniaxial fatigue testing
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