2,640 research outputs found
Exact Renormalization Group and Sine Gordon Theory
The exact renormalization group is used to study the RG flow of quantities in
field theories. The basic idea is to write an evolution operator for the flow
and evaluate it in perturbation theory. This is easier than directly solving
the differential equation. This is illustrated by reproducing known results in
four dimensional field theory and the two dimensional Sine-Gordon
theory. It is shown that the calculation of beta function is somewhat
simplified. The technique is also used to calculate the c-function in two
dimensional Sine-Gordon theory. This agrees with other prescriptions for
calculating c-functions in the literature. If one extrapolates the connection
between central charge of a CFT and entanglement entropy in two dimensions, to
the c-function of the perturbed CFT, then one gets a value for the entanglement
entropy in Sine-Gordon theory that is in exact agreement with earlier
calculations (including one using holography) in arXiv:1610.04233
Event Coreference Resolution by Iteratively Unfolding Inter-dependencies among Events
We introduce a novel iterative approach for event coreference resolution that
gradually builds event clusters by exploiting inter-dependencies among event
mentions within the same chain as well as across event chains. Among event
mentions in the same chain, we distinguish within- and cross-document event
coreference links by using two distinct pairwise classifiers, trained
separately to capture differences in feature distributions of within- and
cross-document event clusters. Our event coreference approach alternates
between WD and CD clustering and combines arguments from both event clusters
after every merge, continuing till no more merge can be made. And then it
performs further merging between event chains that are both closely related to
a set of other chains of events. Experiments on the ECB+ corpus show that our
model outperforms state-of-the-art methods in joint task of WD and CD event
coreference resolution.Comment: EMNLP 201
Stable Atrial Sensing on Long-Term Follow Up of VDD Pacemakers
Background:
The hemodynamic advantages of maintaining AV synchrony through AV synchronous pacing are widely known as compared to single chamber pacing. DDD pacemaker implantation entails higher cost and is technically more challenging than the VDD pacemaker.
Methods:
Seventy one patients underwent VDD lead (Biotronik GmbH, St. Jude Medical and Medtronic Inc.) implantation at KEM hospital, Mumbai during a period of 3 years through subclavian, axillary and cephalic routes for degenerative, post-surgical or congenital high grade atrioventricular or complete heart block. They were followed up regularly for ventricular threshold and P wave amplitude of the floating atrial dipole.
Results:
Follow up data of almost 95% of patients is available for a period of 15.8 ± 6.7 months. P wave amplitude at implant was 2.1 ± 0.7mV and at follow up 1.1 ± 0.6mV with mean ventricular threshold of <0.5V at implant and <1V at follow-up.
Conclusion:
Implantation of a single lead VDD pacemaker is possible in all patients with symptomatic AV block and intact sinus node function without any technical complications. P wave sensing is reliable and consistent with floating atrial lead at an average follow up of 15.8 months, providing an excellent alternative to DDD pacemaker implantation
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