This study develops a three-dimensional finite element torso model with bidomain myocardium to simulate the transmembrane potential (TMP) of the heart induced by defibrillation fields. The inhomogeneities of the torso are modeled as eccentric spherical volumes with both the curvature and the rotation features of cardiac fibers incorporated in the myocardial region. The numerical computation of the finite element bidomain myocardial model is validated by a semianalytic solution. The simulations show that rotation of fiber orientation through the depth of the myocardial wall changes the pattern of polarization and decreases the amount of cardiac tissue polarized compared to the idealized analytic model with no fiber rotation incorporated. The TMP induced by transthoracic and transvenous defibrillation fields are calculated and visualized. The TMP is quantified by a continuous measure of the percentage of myocardial mass above a potential gradient threshold. Using this measure, the root mean square differences in TMP distribution produced by reversing the electrode polarity for anterior-posterior and transvenous electrode configurations are 13.6 and 28.6%, respectively. These results support the claim that a bidomain model of the heart predicts a change of defibrillation threshold with reversed electrode polarity.
When a neutral meson (P 0 orP 0 ) decays to two vector particles, a large number of observables can be constructed from differential decay rate based on the polarization of final state. But, theoretically, all of them are not independent to each other and hence, some relations among observables emerge. These relations have been well studied in the scenario with no T and CP T violation in neutral meson mixing and no direct CP violation as well. In this paper, we have studied the relations among observables in the presence of T , CP and CP T violating effects in mixing only. We find that except four of them, all the other old relations get violated and new relations appear if T and CP T violations in mixing are present. Invalidity of these relation will signify the presence of direct violation of T , CP and CP T (i.e. violation in the decay itself).
Quantum field theory, which is the basis for all of particle physics, requires that all processes respect CP T invariance. It is therefore of paramount importance to test the validity of CP T conservation. In this Letter, we show that the time-dependent, indirect CP asymmetries involving B decays to a CP eigenstate contain enough information to measure T and CP T violation in B 0 -B 0 mixing, in addition to the standard CP -violating weak phases. Entangled B 0B0 states are not required (so that this analysis can be carried out at LHCb, as well as at the B factories), penguin pollution need not be neglected, and the measurements can be made using B 0 d or B 0 s mesons.1 kanirban@imsc.res.in 2 abinashkn@imsc.res.in 3 sinha@imsc.res.in 4 london@lps.umontreal.ca CP T invariance is one of the fundamental principles of quantum field theory: all physical processes are expected to respect this symmetry. Indeed, CP T violation would have a profound impact on physics in general, as it would also lead to a violation of Lorentz symmetry [1,2]. Given its importance to the theoretical framework underlying all of particle physics, much attention has been devoted to experimentally testing the validity of CP T invariance.One of the consequences of CP T invariance in quantum field theory is that a particle and its antiparticle should have the same mass and lifetime. However, these quantities are mostly dominated by the strong or electromagnetic interactions. Given that CP T violation, if nonzero, is certainly a very small effect, it is very difficult to test it by measuring the differences of masses or lifetimes. A more promising area for testing CP T violation is in P 0 -P 0 mixing, where P 0 is a neutral pseudoscalar meson (e.g.,Since this mixing is a second-order electroweak process, small CP T -violating effects may be easier to detect. Now, it is known that, in addition to incorporating CP T violation, the most general B 0 -B 0 mixing matrix also involves T and CP violation. As a consequence, studying CP T violation is impossible without discriminating it from the effects of CP and T violation. That is, the effects of CP , T and CP T violation must be considered together.A first step was taken in Refs. [4,5], with followup papers in Refs. [6][7][8][9][10][11]. The proposed method uses entangled B 0B0 states produced in the decay of the Υ(4S), with one meson decaying to a CP eigenstate (J/ψK S or J/ψK L ) and the other used to tag the flavour. Using this technique, true T -and CP T -violating asymmetries can be measured. The BaBar Collaboration implemented this strategy [12,13], culminating in the measurement of T violation [14].At present, all experimental results are consistent with CP T conservation. On the other hand, an important improvement in statistics is expected at LHCb and Belle II, so that it will be possible to measure the CP -, T -and CP T -violating parameters with greater precision. However, the method using entangled states produced in the decay of the Υ(4S) cannot be used at LHCb. An alternate approach is nee...
This paper shows the development of a system to control inhalation anesthetic concentration delivered to a patient based upon that patient's midlatency auditory evoked potentials (MLAEP's). It was developed and tested in dogs by determining response to the supramaximal stimulus of tail clamping. Prior to tail clamp, the MLAEP was recorded along with inhalational anesthetic concentration and classified as responders or nonresponders as determined by tail clamping. This was performed at a number of different anesthetic levels to obtain a data training set. The MLAEP's were compacted by means of discrete time wavelet transform (DTWT), and together with anesthetic concentration value, a stepwise discriminant analysis (SDA) was performed to determine those features which could separate responders from nonresponders. It was determined that only three features were necessary for this recognition. These features were then used to train a four-layer artificial neural network (ANN) to separate the responders from nonresponders. The network was tested using a separate set of data, resulting in a 93% recognition rate in the anesthetic transition zone between responders and nonresponders, and 100% recognition rate outside this zone. The anesthetic controller used this ANN combined with fuzzy logic and rule-based control. A set of ten animal experiments were performed to test the robustness of this controller. Acceptable clinical performance was obtained, showing the feasibility of this approach.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.