29,051 research outputs found
Major Outcomes in Atrial Fibrillation Patients with One Risk Factor: Impact of Time in Therapeutic Range
BACKGROUND:
The benefits and harms of oral anticoagulation (OAC) therapy in patients with only one stroke risk factor (i.e. CHA2DS2-VASc= 1 in males, or 2 in females) has been subject of debate.
METHODS:
We analysed all patients with only one stroke risk factor from the merged datasets of SPORTIF III and V trials. Anticoagulation control was defined according to time in therapeutic range (TTR).
RESULTS:
Of the original trial cohort, 1,097 patients had only one stroke risk factor. Stroke/systemic thromboembolic event had an incidence of 0.9 per 100 patient-years, with an incidence of 1.6 per 100 patient-years for all-cause death and 2.3%/patient-years for the composite outcome of stroke/systemic thromboembolic event/all-cause death. There were no significant differences in the risk for stroke/systemic thromboembolic event between sexes, nor between the different stroke risk factors amongst these atrial fibrillation patients with only one stroke risk factor. Cox regression analysis in patients treated with warfarin only found TTR to be inversely associated with stroke/systemic thromboembolic event (p=0.034) and all-cause death (p=0.015). Chronic heart failure was significantly associated with the outcome of all-cause death (p=0.0019) and the composite outcome of stroke/systemic thromboembolic event/all-cause death (p=0.021). There was a significant inverse linear association between TTR and the cumulative risk for both stroke/systemic thromboembolic event and all-cause death (both p<0.001).
CONCLUSIONS:
In atrial fibrillation patients with only one additional stroke risk factor (i.e. CHA2DS2-VASc= 1 in males or 2 in females), rates of major adverse events (stroke/systemic thromboembolic event, mortality) were high, despite anticoagulation. TTR in warfarin-treated patients was inversely associated with the occurrence of both stroke/systemic thromboembolic event and all-cause death
Second-Order Coding Rates for Channels with State
We study the performance limits of state-dependent discrete memoryless
channels with a discrete state available at both the encoder and the decoder.
We establish the epsilon-capacity as well as necessary and sufficient
conditions for the strong converse property for such channels when the sequence
of channel states is not necessarily stationary, memoryless or ergodic. We then
seek a finer characterization of these capacities in terms of second-order
coding rates. The general results are supplemented by several examples
including i.i.d. and Markov states and mixed channels
The Third-Order Term in the Normal Approximation for the AWGN Channel
This paper shows that, under the average error probability formalism, the
third-order term in the normal approximation for the additive white Gaussian
noise channel with a maximal or equal power constraint is at least . This matches the upper bound derived by
Polyanskiy-Poor-Verd\'{u} (2010).Comment: 13 pages, 1 figur
Gate-tunable coherent perfect absorption of terahertz radiation in graphene
Perfect absorption of radiation in a graphene sheet may play a pivotal role
in the realization of technologically relevant optoelectronic devices. In
particular, perfect absorption of radiation in the terahertz (THz) spectral
range would tremendously boost the utility of graphene in this difficult range
of photon energies, which still lacks cheap and robust devices operating at
room temperature. In this work we show that unpatterned graphene flakes
deposited on appropriate substrates can display gate-tunable coherent perfect
absorption (CPA) in the THz spectral range. We present theoretical estimates
for the CPA operating frequency as a function of doping, which take into
account the presence of common sources of disorder in graphene samples.Comment: To appear in 2D Material
Second-Order Asymptotics for the Classical Capacity of Image-Additive Quantum Channels
We study non-asymptotic fundamental limits for transmitting classical
information over memoryless quantum channels, i.e. we investigate the amount of
classical information that can be transmitted when a quantum channel is used a
finite number of times and a fixed, non-vanishing average error is permissible.
We consider the classical capacity of quantum channels that are image-additive,
including all classical to quantum channels, as well as the product state
capacity of arbitrary quantum channels. In both cases we show that the
non-asymptotic fundamental limit admits a second-order approximation that
illustrates the speed at which the rate of optimal codes converges to the
Holevo capacity as the blocklength tends to infinity. The behavior is governed
by a new channel parameter, called channel dispersion, for which we provide a
geometrical interpretation.Comment: v2: main results significantly generalized and improved; v3: extended
to image-additive channels, change of title, journal versio
Exactly solvable one-qubit driving fields generated via non-linear equations
Using the Hubbard representation for we write the time-evolution
operator of a two-level system in the disentangled form. This allows us to map
the corresponding dynamical law into a set of non-linear coupled equations. In
order to find exact solutions, we use an inverse approach and find families of
time-dependent Hamiltonians whose off-diagonal elements are connected with the
Ermakov equation. The physical meaning of the so-obtained Hamiltonians is
discussed in the context of the nuclear magnetic resonance phenomeno
Real-time marker-less multi-person 3D pose estimation in RGB-Depth camera networks
This paper proposes a novel system to estimate and track the 3D poses of
multiple persons in calibrated RGB-Depth camera networks. The multi-view 3D
pose of each person is computed by a central node which receives the
single-view outcomes from each camera of the network. Each single-view outcome
is computed by using a CNN for 2D pose estimation and extending the resulting
skeletons to 3D by means of the sensor depth. The proposed system is
marker-less, multi-person, independent of background and does not make any
assumption on people appearance and initial pose. The system provides real-time
outcomes, thus being perfectly suited for applications requiring user
interaction. Experimental results show the effectiveness of this work with
respect to a baseline multi-view approach in different scenarios. To foster
research and applications based on this work, we released the source code in
OpenPTrack, an open source project for RGB-D people tracking.Comment: Submitted to the 2018 IEEE International Conference on Robotics and
Automatio
A Tight Upper Bound for the Third-Order Asymptotics for Most Discrete Memoryless Channels
This paper shows that the logarithm of the epsilon-error capacity (average
error probability) for n uses of a discrete memoryless channel is upper bounded
by the normal approximation plus a third-order term that does not exceed 1/2
log n + O(1) if the epsilon-dispersion of the channel is positive. This matches
a lower bound by Y. Polyanskiy (2010) for discrete memoryless channels with
positive reverse dispersion. If the epsilon-dispersion vanishes, the logarithm
of the epsilon-error capacity is upper bounded by the n times the capacity plus
a constant term except for a small class of DMCs and epsilon >= 1/2.Comment: published versio
A band structure scenario for the giant spin-orbit splitting observed at the Bi/Si(111) interface
The Bi/Si(111) (sqrt{3} x sqrt{3})R30 trimer phase offers a prime example of
a giant spin-orbit splitting of the electronic states at the interface with a
semiconducting substrate. We have performed a detailed angle-resolved
photoemission (ARPES) study to clarify the complex topology of the hybrid
interface bands. The analysis of the ARPES data, guided by a model
tight-binding calculation, reveals a previously unexplored mechanism at the
origin of the giant spin-orbit splitting, which relies primarily on the
underlying band structure. We anticipate that other similar interfaces
characterized by trimer structures could also exhibit a large effect.Comment: 11 pages, 13 figure
Theory of correlations in strongly interacting fluids of two-dimensional dipolar bosons
Ground-state properties of a two-dimensional fluid of bosons with repulsive
dipole-dipole interactions are studied by means of the Euler-Lagrange
hypernetted-chain approximation. We present a self-consistent semi-analytical
theory of the pair distribution function and ground-state energy of this
system. Our approach is based on the solution of a zero-energy scattering
Schr\"{o}dinger equation for the "pair amplitude" with an
effective potential from Jastrow-Feenberg correlations. We find excellent
agreement with quantum Monte Carlo results over a wide range of coupling
strength, nearly up to the critical coupling for the liquid-to-crystal quantum
phase transition. We also calculate the one-body density matrix and related
quantities, such as the momentum distribution function and the condensate
fraction.Comment: 8 pages, 8 figures, submitte
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