Weak Coupling Expansion of Yang-Mills Theory on Recursive Infinite Genus Surfaces

We analyze the partition function of two dimensional Yang-Mills theory on a family of surfaces of infinite genus. These surfaces have a recursive structure, which was used by one of us to compute the partition function that results in a generalized Migdal formula. In this paper we study the `small area' (weak coupling) expansion of the partition function, by exploiting the fact that the generalized Migdal formula is analytic in the (complexification of the) Euler characteristic. The structure of the perturbative part of the weak coupling expansion suggests that the moduli space of flat connections (of the SU(2) and SO(3) theories) on these infinite genus surfaces are well defined, perhaps in an appropriate regularization.Comment: 1+18 pages, 2 figure

Stochastic Differential Equation Noise Analysis of Common-Source Amplifier with Capacitive Load

In this paper, we analyse the effect of noise in a common-source amplifier with capacitive load working at high frequencies. Extrinsic noise is analyzed using time domain method employing techniques from stochastic calculus. Stochastic differential equations are used to obtain autocorrelation functions of the output noise voltage and other solution statistics like mean and variance. The analysis leads to important design implications for improved noise characteristics of the common-source amplifier

Honeycomb antiferromagnet with a triply degenerate dimer ground state

We present an antiferromagnetic quantum spin-1/2 model on honeycomb lattice. It has two parts, one of which is the usual nearest-neighbor Heisenberg model. The other part is a certain multiple spin interaction term, introduced by us, which is exactly solvable for the ground state. Without the Heisenberg part, the model has an exact threefold degenerate dimer ground state. This exact ground state is also noted to exist for the general spin-S case. For the spin-1/2 case, we further carry out the triplon analysis in the ground state, to study the competition between the Heisenberg and the multiple spin interactions. This approximate calculation exhibits a continuous quantum phase transition from the dimer order to N\'eel order.Comment: 6+ pages, 10 figures, submitted to Phys. Rev.

Three-Dimensional Myoarchitecture of the Lower Esophageal Sphincter and Esophageal Hiatus Using Optical Sectioning Microscopy.

Studies to date have failed to reveal the anatomical counterpart of the lower esophageal sphincter (LES). We assessed the LES and esophageal hiatus morphology using a block containing the human LES and crural diaphragm, serially sectioned at 50 μm intervals and imaged at 8.2 μm/pixel resolution. A 3D reconstruction of the tissue block was reconstructed in which each of the 652 cross sectional images were also segmented to identify the boundaries of longitudinal (LM) and circular muscle (CM) layers. The CM fascicles on the ventral surface of LES are arranged in a helical/spiral fashion. On the other hand, the CM fascicles from the two sides cross midline on dorsal surface and continue as sling/oblique muscle on the stomach. Some of the LM fascicles of the esophagus leave the esophagus to enter into the crural diaphragm and the remainder terminate into the sling fibers of the stomach. The muscle fascicles of the right crus of diaphragm which form the esophageal hiatus are arranged like a "noose" around the esophagus. We propose that circumferential squeeze of the LES and crural diaphragm is generated by a unique myo-architectural design, each of which forms a "noose" around the esophagus

Fetal ultrasonography of Chiari II malformation

Chiari II malformation is a complex hindbrain malformation, embryologically presenting as a neural tube closure defect comprising of downward herniation of cerebellum, pons, medulla and fourth ventricle into the spinal canal. We present a case of Chiari II malformation depicting essential sonographic observations at 20 weeks of gestation. Such fetuses have high morbidity and mortality and early diagnosis of such a disease is essential in terms of planning including pregnancy termination or neurosurgical procedures for follow-up pregnancy. Ultrasonography is an indispensable modality for the evaluation of fetal anatomy, growth, and such congenital anomalies