Influence of Slippery Pacemaker Leads on Lead-Induced Venous Occlusion

The use of medical devices such as pacemakers and implantable cardiac defibrillators have become commonplace to treat arrhythmias. Pacing leads with electrodes are used to send electrical pulses to the heart to treat either abnormally slow heart rates, or abnormal rhythms. Lead induced vessel occlusion, which is commonly seen after placement of pacemaker or implantable cardiac defibrillators leads, may result in lead malfunction and/or superior vena cava syndrome, and makes lead extraction difficult. The association between the anatomic locations at risk for thrombosis and regions of venous stasis have been reported previously. The computational studies reveal obvious flow stasis in the proximity of the leads, due to the no-slip boundary condition imposed on the lead surface. With recent technologies capable of creating slippery surfaces that can repel complex fluids including blood, we explore computationally how local structures may be altered in the regions around the leads when the no-slip boundary condition on the lead surface is relaxed using various slip lengths. The slippery surface is modeled by a Navier slip boundary condition. Analytical studies are performed on idealized geometries, which were then used to validate numerical simulations. A patient-specific model is constructed and studied numerically to investigate the influence of the slippery surface in a more physiologically realistic environment. The findings evaluate the possibility of reducing the risk of lead-induced thrombosis and occlusion by implementing a slippery surface conditions on the leads

The Affordable Care Act raises the stakes on worker classification; what does this mean for the Voluntary Classification Settlement Program

This research considers worker classification and the many implications an employer must consider when classifying a worker as employee or independent contractor. One implication relates to healthcare benefits and healthcare taxes. As such, this research will evaluate the new healthcare taxes and implications resulting from the Affordable Care Act. Furthermore, this research will relate and explain worker classification with regards to the Voluntary Classification Settlement Program. This is a program offered by the Internal Revenue Service allowing employers to prospectively classify workers as employees with tax relief for past misclassification. The healthcare implications from the Affordable Care Act have raised the stakes on worker classification. This research will confirm whether this will provide greater incentive for employers to classify workers as employees or independent contractors. This research considers worker classification and the many implications an employer must consider when classifying a worker as employee or independent contractor. One implication relates to healthcare benefits and healthcare taxes. As such, this research will evaluate the new healthcare taxes and implications resulting from the Affordable Care Act. Furthermore, this research will relate and explain worker classification with regards to the Voluntary Classification Settlement Program. This is a program offered by the Internal Revenue Service allowing employers to prospectively classify workers as employees with tax relief for past misclassification. The healthcare implications from the Affordable Care Act have raised the stakes on worker classification. This research will confirm whether this will provide greater incentive for employers to classify workers as employees or independent contractors

Two point third order correlation functions for quasi-geostrophic turbulence: Kolmogorov-Landau approach

We use the more intuitive approach due to Kolmogorov (and subsequently, Landau in his text on fluid dynamics) to calculate some third-order structure functions for quasi-geostrophic turbulence for the forward cascade of pseudo-potential enstrophy and the inverse energy cascade in quasi-geostrophic turbulence

Quaternionic Hyperbolic Fenchel-Nielsen Coordinates

Let $Sp(2,1)$ be the isometry group of the quaternionic hyperbolic plane ${{\bf H}_{\mathbb H}}^2$. An element $g$ in $Sp(2,1)$ is `hyperbolic' if it fixes exactly two points on the boundary of ${{\bf H}_{\mathbb H}}^2$. We classify pairs of hyperbolic elements in $Sp(2,1)$ up to conjugation. A hyperbolic element of $Sp(2,1)$ is called `loxodromic' if it has no real eigenvalue. We show that the set of $Sp(2,1)$ conjugation orbits of irreducible loxodromic pairs is a $(\mathbb C {\mathbb P}^1)^4$-bundle over a topological space that is locally a semi-analytic subspace of ${\mathbb R}^{13}$. We use the above classification to show that conjugation orbits of `geometric' representations of a closed surface group (of genus $g \geq 2$) into $Sp(2,1)$ can be determined by a system of $42g-42$ real parameters. Further, we consider the groups $Sp(1,1)$ and $GL(2, {\mathbb H})$. These groups also act by the orientation-preserving isometries of the four and five dimensional real hyperbolic spaces respectively. We classify conjugation orbits of pairs of hyperbolic elements in these groups. These classifications determine conjugation orbits of `geometric' surface group representations into these groups.Comment: major structural revision. Restructured the exposition. Introduction re-writte

Rotating and Orbiting Strings in Dp-brane background

We probe the open fundamental strings in Dp-brane (p=1, 3, 5) backgrounds and find new classes of rotating and orbiting string solutions. We show that for various worldsheet embedding ansatz we get solutions of the string equations of motion that correspond to the well known giant magnon and single spikes, in addition to few new solutions corresponding to the orbiting strings. We make a systematic study of both rigidly rotating and orbiting strings in D1, D3 and D5-brane backgrounds.Comment: 27 page