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Time-trends and treatment gaps in the antithrombotic management of patients with atrial fibrillation after percutaneous coronary intervention: Insights from the CHUM AF-STENT Registry.
BACKGROUND: The management of atrial fibrillation and flutter (AF) patients undergoing percutaneous coronary intervention (PCI) has undergone a rapid recent evolution. In 2016, the Canadian Cardiovascular Society (CCS) published expert recommendations to help guide clinicians in balancing bleeding and thrombotic risks in these patients. HYPOTHESIS: Antithrombotic regimen prescriptions for AF patients undergoing PCI evolved after the publication of the 2016 CCS AF guidelines. METHODS: A prospective cohort of AF patients undergoing PCI with placement of a coronary stent from a single tertiary academic center was analyzed for the recommended antithrombotic regimen at discharge. Prescribing behavior was compared between three time periods (Cohort A [2010-2011]; Cohort B [2014-2015]; Cohort C [2017]) using the χ2 test. In addition, antithrombotic management in Cohorts B and C were compared to guideline-recommended therapy. RESULTS: A total of 459 patients with AF undergoing PCI were identified. Clinical and procedural characteristics were similar between cohorts, with the exception of an increase in drug-eluting stent (DES) use over time (P < .01). Overall, the rate of oral anticoagulation (OAC) increased over time (P < .01), associated with an increase in nonvitamin K OAC prescription (P < .01) and a concomitant decrease in vitamin K antagonist prescription (P < .01). Despite this, the overall rate of anticoagulation remains below what would be predicted with perfect guideline compliance (75% vs 94%, P < .01). CONCLUSION: There has been a dramatic shift in clinical practice for AF patients requiring PCI, with increases in prescription of OAC even in the context of an increase in the use of DES. However, room for further practice optimization still exists
Sharp transition for single polarons in the one-dimensional Su-Schrieffer-Heeger model
We study a single polaron in the Su-Schrieffer-Heeger (SSH) model using four
different techniques (three numerical and one analytical). Polarons show a
smooth crossover from weak to strong coupling, as a function of the
electron-phonon coupling strength , in all models where this coupling
depends only on phonon momentum . In the SSH model the coupling also depends
on the electron momentum ; we find it has a sharp transition, at a critical
coupling strength , between states with zero and nonzero momentum of
the ground state. All other properties of the polaron are also singular at
, except the average number of phonons in the polaronic
cloud. This result is representative of all polarons with coupling depending on
and , and will have important experimental consequences (eg., in ARPES
and conductivity experiments)
A Study of the Formation of Single- and Double-Walled Carbon Nanotubes by a CVD Method
The reduction in H2/CH4 atmosphere of aluminum-iron oxides produces metal particles small enough to catalyze the formation of single-walled carbon nanotubes. Several experiments have been made using the same temperature profile and changing only the maximum temperature (800-1070 °C). Characterizations of the catalyst materials are performed using notably 57Fe Mo¨ssbauer spectroscopy. Electron microscopy and a macroscopical method are used to characterize the nanotubes. The nature of the iron species (Fe3+, R-Fe, ç-Fe-C, Fe3C) is correlated to their location in the material. The nature of the particles responsible for the high-temperature formation of the nanotubes is probably an Fe-C alloy which is, however, found as Fe3C by postreaction analysis. Increasing the reduction temperature increases the reduction yield and thus favors the formation of surface-metal particles, thus producing more nanotubes. The obtained carbon nanotubes are mostly single-walled and double-walled with an average diameter close to 2.5 nm. Several formation mechanisms are thought to be active. In particular, it is shown that the second wall can grow inside the first one but that subsequent ones are formed outside. It is also possible that under given experimental conditions, the smallest (<2 nm) catalyst particles preferentially produce double-walled rather than single-walled carbon nanotubes
New pixelized Micromegas detector for the COMPASS experiment
New Micromegas (Micro-mesh gaseous detectors) are being developed in view of
the future physics projects planned by the COMPASS collaboration at CERN.
Several major upgrades compared to present detectors are being studied:
detectors standing five times higher luminosity with hadron beams, detection of
beam particles (flux up to a few hundred of kHz/mm^2, 10 times larger than for
the present detectors) with pixelized read-out in the central part, light and
integrated electronics, and improved robustness. Studies were done with the
present detectors moved in the beam, and two first pixelized prototypes are
being tested with muon and hadron beams in real conditions at COMPASS. We
present here this new project and report on two series of tests, with old
detectors moved into the beam and with pixelized prototypes operated in real
data taking condition with both muon and hadron beams.Comment: 11 pages, 5 figures, proceedings to the Micro-Pattern Gaseous
Detectors conference (MPGD2009), 12-15 June 2009, Kolympari, Crete, Greece
Minor details added and language corrections don
The Force-Velocity Relation for Growing Biopolymers
The process of force generation by the growth of biopolymers is simulated via
a Langevin-dynamics approach. The interaction forces are taken to have simple
forms that favor the growth of straight fibers from solution. The
force-velocity relation is obtained from the simulations for two versions of
the monomer-monomer force field. It is found that the growth rate drops off
more rapidly with applied force than expected from the simplest theories based
on thermal motion of the obstacle. The discrepancies amount to a factor of
three or more when the applied force exceeds 2.5kT/a, where a is the step size
for the polymer growth. These results are explained on the basis of restricted
diffusion of monomers near the fiber tip. It is also found that the mobility of
the obstacle has little effect on the growth rate, over a broad range.Comment: Latex source, 9 postscript figures, uses psfig.st
Eikonal analysis of Coulomb distortion in quasi-elastic electron scattering
An eikonal expansion is used to provide systematic corrections to the eikonal
approximation through order , where is the wave number. Electron
wave functions are obtained for the Dirac equation with a Coulomb potential.
They are used to investigate distorted-wave matrix elements for quasi-elastic
electron scattering from a nucleus. A form of effective-momentum approximation
is obtained using trajectory-dependent eikonal phases and focusing factors.
Fixing the Coulomb distortion effects at the center of the nucleus, the
often-used ema approximation is recovered. Comparisons of these approximations
are made with full calculations using the electron eikonal wave functions. The
ema results are found to agree well with the full calculations.Comment: 12 pages, 6 Postscript figure
Universal pattern in (e,e'p) at large missing momenta: quasi-deuteron or diffractive final state interactions?
The intrinsic single particle momentum distributions in nuclei are supposed
to show a universal behavior at large momenta, dominated by short-range
correlated pairs, or quasi-deuterons. We discuss whether the quasi-deuteron
universality survives the final state interaction effects, which are present in
the missing momentum spectra measured in experiments at GeV
energies. We demonstrate that in the observed missing momentum spectra an
approximate universality is present, but originating from the universal pattern
of diffractive final state interactions of the struck proton independent of the
target nucleus.Comment: 10 pages, Latex, 3 uuencoded figure
New pixelized Micromegas detector with low discharge rate for the COMPASS experiment
New Micromegas (Micro-mesh gaseous detectors) are being developed in view of
the future physics projects planned by the COMPASS collaboration at CERN.
Several major upgrades compared to present detectors are being studied:
detectors standing five times higher luminosity with hadron beams, detection of
beam particles (flux up to a few hundred of kHz/mm^{2}, 10 times larger than
for the present Micromegas detectors) with pixelized read-out in the central
part, light and integrated electronics, and improved robustness. Two solutions
of reduction of discharge impact have been studied, with Micromegas detectors
using resistive layers and using an additional GEM foil. Performance of such
detectors has also been measured. A large size prototypes with nominal active
area and pixelized read-out has been produced and installed at COMPASS in 2010.
In 2011 prototypes featuring an additional GEM foil, as well as an resistive
prototype, are installed at COMPASS and preliminary results from those
detectors presented very good performance. We present here the project and
report on its status, in particular the performance of large size prototypes
with an additional GEM foil.Comment: 11 pages, 5 figures, proceedings to the Micro-Pattern Gaseous
Detectors conference (MPGD2011), 29-31 August 2011, Kobe, Japa
Event-based control strategy for consensus of a group of VTOL-UAVs
International audienceThis paper presents the development of a collaborative event-based control applied to the problem of consensus and formation of a group of VTOL-UAVs (Vertical Takeoff and Landing, Unmanned Aerial Vehicles). Each VTOL-UAV decides, based on the difference of its current state (linear position and velocity) and its latest broadcast state, when it has to send a new value to its neighbors. The asymptotic convergence to average consensus or desired formation is depicted via numerical simulations
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