Estimation of elastic and viscous properties of the left ventricle based on annulus plane harmonic behavior

Assessment of left ventricular (LV) function with an emphasis on contractility has been a challenge in cardiac mechanics during the recent decades. The LV function is usually described by the LV pressurevolume (P-V) diagram. The standard P-V diagrams are easy to interpret but difficult to obtain and require invasive instrumentation for measuring the corresponding volume and pressure data. In the present study, we introduce a technique that can estimate the viscoelastic properties of the LV based on harmonic behavior of the ventricular chamber and it can be applied non-invasively as well. The estimation technique is based on modeling the actual long axis displacement of the mitral annulus plane toward the cardiac base as a linear damped oscillator with time-varying coefficients. The time-varying parameters of the model were estimated by a standard Recursive Linear Least Squares (RLLS) technique. LV stiffness at end-systole and end diastole was in the range of 61.86-136.00 dyne/g.cm and 1.25-21.02 dyne/g.cm, respectively. The only input used in this model was the long axis displacement of the annulus plane, which can also be obtained non-invasively using tissue Doppler or MR imaging

The \u3ci\u3eTryphê\u3c/i\u3e of the Sybarites: A Historiographical Problem in Athenaeus

A large number of the most informative fragments of the Hellenistic Greek historians are transmitted by Athenaeus. Unlike the frequently jejune evidence provided by scholiasts, lexicographers, and the like, these texts allow us to draw historiographical conclusions about lost writers: on this basis, scholars have posited, for example, the place of a given author in the Hellenistic “schools” of history. The importance of Athenaeus as a source for history-writing between Xenophon and Diodorus calls for detailed study of the Deipnosophist’s method of citing these lost authors. The present article focuses on Athenaeus’ testimony concerning the downfall of Archaic Sybaris through luxury and excess in order to show that certain phrases, sentence patterns and even trains of thought can be reliably identified as belonging to Athenaeus rather than the cited authority. This discovery entails surprising results: traditions ascribing the destruction of Sybaris to morally corrosive luxury are late and of little historical value. More generally, the debilitating effects of luxury cannot serve as an exemplum supporting the claim that Hellenistic writers tended to explain historical events through moral causes; apparent evidence for this causal nexus is better assigned to Athenaeus than to the historians he names. In view of these conclusions, a cautious reassessment of all Athenaeus’ testimony on fragmentary historians is appropriate

Approaching Questions of Text Reuse in Ancient Greek Using Computational Syntactic Stylometry

We are investigating methods by which data from dependency syntax treebanks of ancient Greek can be applied to questions of authorship in ancient Greek historiography. From the Ancient Greek Dependency Treebank were constructed syntax words (sWords) by tracing the shortest path from each leaf node to the root for each sentence tree. This paper presents the results of a preliminary test of the usefulness of the sWord as a stylometric discriminator. The sWord data was subjected to clustering analysis. The resultant groupings were in accord with traditional classifications. The use of sWords also allows a more fine-grained heuristic exploration of difficult questions of text reuse. A comparison of relative frequencies of sWords in the directly transmitted Polybius book 1 and the excerpted books 9–10 indicate that the measurements of the two texts are generally very close, but when frequencies do vary, the differences are surprisingly large. These differences reveal that a certain syntactic simplification is a salient characteristic of Polybius’ excerptor, who leaves conspicuous syntactic indicators of his modifications

Approaching Questions of Text Reuse in Ancient Greek Using Computational Syntactic Stylometry

We are investigating methods by which data from dependency syntax treebanks of ancient Greek can be applied to questions of authorship in ancient Greek historiography. From the Ancient Greek Dependency Treebank were constructed syntax words (sWords) by tracing the shortest path from each leaf node to the root for each sentence tree. This paper presents the results of a preliminary test of the usefulness of the sWord as a stylometric discriminator. The sWord data was subjected to clustering analysis. The resultant groupings were in accord with traditional classifications. The use of sWords also allows a more fine-grained heuristic exploration of difficult questions of text reuse. A comparison of relative frequencies of sWords in the directly transmitted Polybius book 1 and the excerpted books 9–10 indicate that the measurements of the two texts are generally very close, but when frequencies do vary, the differences are surprisingly large. These differences reveal that a certain syntactic simplification is a salient characteristic of Polybius’ excerptor, who leaves conspicuous syntactic indicators of his modifications

The \u3ci\u3eTryphê\u3c/i\u3e of the Sybarites: A Historiographical Problem in Athenaeus

A large number of the most informative fragments of the Hellenistic Greek historians are transmitted by Athenaeus. Unlike the frequently jejune evidence provided by scholiasts, lexicographers, and the like, these texts allow us to draw historiographical conclusions about lost writers: on this basis, scholars have posited, for example, the place of a given author in the Hellenistic “schools” of history. The importance of Athenaeus as a source for history-writing between Xenophon and Diodorus calls for detailed study of the Deipnosophist’s method of citing these lost authors. The present article focuses on Athenaeus’ testimony concerning the downfall of Archaic Sybaris through luxury and excess in order to show that certain phrases, sentence patterns and even trains of thought can be reliably identified as belonging to Athenaeus rather than the cited authority. This discovery entails surprising results: traditions ascribing the destruction of Sybaris to morally corrosive luxury are late and of little historical value. More generally, the debilitating effects of luxury cannot serve as an exemplum supporting the claim that Hellenistic writers tended to explain historical events through moral causes; apparent evidence for this causal nexus is better assigned to Athenaeus than to the historians he names. In view of these conclusions, a cautious reassessment of all Athenaeus’ testimony on fragmentary historians is appropriate

Patient-specific CFD simulation of intraventricular haemodynamics based on 3D ultrasound imaging

Background: The goal of this paper is to present a computational fluid dynamic (CFD) model with moving boundaries to study the intraventricular flows in a patient-specific framework. Starting from the segmentation of real-time transesophageal echocardiographic images, a CFD model including the complete left ventricle and the moving 3D mitral valve was realized. Their motion, known as a function of time from the segmented ultrasound images, was imposed as a boundary condition in an Arbitrary Lagrangian-Eulerian framework. Results: The model allowed for a realistic description of the displacement of the structures of interest and for an effective analysis of the intraventricular flows throughout the cardiac cycle. The model provides detailed intraventricular flow features, and highlights the importance of the 3D valve apparatus for the vortex dynamics and apical flow. Conclusions: The proposed method could describe the haemodynamics of the left ventricle during the cardiac cycle. The methodology might therefore be of particular importance in patient treatment planning to assess the impact of mitral valve treatment on intraventricular flow dynamics

The Second Rodney King Trial: Justice in Jeopardy?

This Comment will trace the roots of the Double Jeopardy Clause of the U.S. Constitution and provide a detailed look at the development of the dual sovereignty doctrine. After this overview, it will analyze the historical, legal and policy arguments advanced by supporters and opponents of the doctrine. It will examine proposals for altering or abolishing the doctrine. Finally, in light of the underlying analysis, it will revisit the Rodney King case and examine whether the defendants\u27 second trial - or any successive prosecution - is justified