Monopoles and Confinement in Lattice-Gauge Theory.

The mechanism by which quarks, believed to be the fundamental constituents of matter, are prevented from existing in the free state is still unknown. The phenomenon of quark confinement is one of the fundamental problems in physics. One of the most viable candidates for a hypothesis of confinement is the dual superconductor mechanism that likens quark confinement to the Meissner effect in superconductors. The peculiarities of quark interactions make a numerical approach to the subject a necessity, and therefore, much of the work in this area has been done through the methods of lattice gauge theory, with the simplicities afforded by putting spacetime on a four-dimensional grid. Over the years a large amount of indirect evidence has accumulated that the dual superconductor hypothesis does indeed lead to quark confinement but unambiguous evidence has eluded research efforts until recently. This work presents the first direct proof of a Meissner-like effect that leads to confinement, using the numerical techniques of lattice gauge theory. It is shown that for a U(1) lattice gauge theory, that serves as a toy model for the real world of quarks, a dual London relation and an electric fluxoid quantization condition is satisfied, allowing us to conclude that the vacuum in this case acts like an extreme type-II superconductor, and that quarks are confined. We also show that SU(2) lattice gauge theory, which is qualitatively different and another step closer to reality, shows a Meissner-like effect. In contrast to the U(1) case, our results are found consistent with a dual version of the Ginsburg-Landau theory of superconductivity. We find reason to believe that the SU(2) vacuum behaves like a superconductor on the borderline between type-I and type-II. Our approach paves the way for a study of the more complicated theory, quantum chromodynamics, that is believed to describe quarks

A study on environmental corrosion of gilded heritage structures of Royal Palace Patan, Nepal

This article presents the results of corrosion study carried out on 17th century gilded sample procured from the metallic golden window of Patan Royal Palace, Nepal. The characterization techniques employed in the study provide the detailed information about the environmental pollutants responsible for the corrosion and degradation of gilded window. The analytical results have revealed that the window has been made of pure copper sheet on which traditional mercury-amalgam gilding technique has been used. Particulate matters like elemental carbon, sulphur dioxide, chlorine and organic matter have been found to be the main factors responsible for the corrosion and degradation of gilded surface. The information obtained from the present study is expected to be the source of understanding and solution for the protection and conservation of the gilded heritage of Nepal

Vacuum structure of pure gauge theories on the lattice

We present results from simulations on two aspects of quark confinement in the pure gauge sector. First is the calculation of the profile of the flux tube connecting a static $q \bar{q}$ pair in $SU(2)$. By using the Michael sum rules as a constraint we give evidence that the energy density at the center of the flux tube goes to a constant as a function of quark separation. Slow variation of the width and energy density is not ruled out. Secondly in the confined phase of lattice $U(1)$ we calculate the curl of the magnetic monopole current and show that the dual London equation is satisfied and that the electric fluxoid is quantized.Comment: 14 pages (no figures, please request preprint), LSU HE NO. 130-199

Prenatal diagnosis of fetal cholelithiasis: a rare case

Fetal gallstones are a rare ultrasonography finding. Authors came across a similar case of fetal gallstones detected in routine third trimester scan. Patient had Rh negative blood group which might be the cause of fetal gallstone in this case however in most cases, the cause is undefined. Case was confirmed to have gallstones in postnatal scan which eventually resolved spontaneously within 1 month. The presence of gallstones in the fetus does not alter the fetal prognosis or obstetrical management since complete resolution is seen in most of the cases in late third trimester or neonatal period which may be due to either spontaneous passage of gallstones during early neonatal period or dilution of cholesterol crystals with postnatal hydration

Supply chain production model with preservation technology under fuzzy environment

In this paper, an attempt is made to characterize the preservation technology for deteriorating items to reduce the deterioration rate. This model assumes a single producer and single supplier and formulates a production model with a time varying rate of deterioration rate. Here production and demand are treated as a fuzzy variables and total cost is minimized for both the crisp and fuzzy model. Shortage is allowed on the supplier’s part, which is partially backlogged. A solution procedure is presented to determine an optimal replenishment cycle and total cost per unit time, which is a convex function of preservation technology cost. Results have been validated with relevant example. In a way, the proposed model provides a unique theory to reduce the deterioration rate for the production model

How do the women of Open Source support each other?

This paper presents an analysis of 10,698 messages from five online forums with 1,344 participants to identify patterns of activity, major topics of discussion, and the type of social support available for participants in these Open Source Software (OSS) forums. We found that these forums serve as safe spaces shared by marginalized populations, for collaborating, networking and most importantly providing social support to each other