D-brane Dynamics and the Quantum Hall Effect

We study the recently proposed D-brane configuration [hep-th/0010105] modeling the quantum Hall effect, focusing on the nature of the interactions between the charged particles. Our analysis indicates that the interaction is repulsive, which it should be for the ground state of the system to behave as a quantum Hall liquid. The strength of interactions varies inversely with the filling fraction, leading us to conclude that a Wigner crystal is the ground state at small nu. For larger rational nu (still less than unity), it is reasonable to expect a fractional quantum Hall ground state.Comment: 13 pages, latex, two figures. v2: Corrected cyclotron gap makes quantum Hall ground state more likel

Frey’s procedure: short term follow up results in terms of pain, endocrine and exocrine status, a tertiary care centre experience

Background: Chronic pancreatitis, a debilitating disease which affects the patient to an extent to render him bedridden sometimes and often make him/her unable to perform daily work, leading to poor quality of life, severe emotional stress and financial burden. Frey’s procedure one of the most commonly performed surgery in patient of chronic pancreatitis with stones in pancreatic duct and small inflammatory head mass. This procedure had shown promising results in terms of pain control with unclear outcome with respect to exocrine and endocrine status.Methods: Study was conducted in Government Kilpauk Medical College, Chennai during March 2016 to December 2019. Total 21 patients were followed up for 18 months and Post-operative pain was analysed using pain scoring system used by Bloechle et al. Exocrine status in terms of diarrhea, bloating sensation and Fecal Elastase level(preoperative and postoperative) were analysed. Patient glycaemic status were also analysed and compared. Patient Nutritional status was analysed in terms of weight gain.Results: In this study there was significant improvement in pain after surgery in terms of VAS pain Score (Preop Mean-82.14, Post-op Mean- 9.76, p<0.001) , frequency of pain (Preop Mean-78.57, Post-op Mean- 14.29, p<0.001), analgesia required (Preop Mean-15, Post-op Mean- 3.10, p<0.001), and inability to work due to pain (Preop Mean-80.95, Post-op Mean- 11.90, p<0.001). Overall total Pain score was significantly improved after surgery (Preop Mean-256.67, Post-op Mean- 39.05, p<0.001). There was significant weight gain and significant improvement in Fecal Elastase level in patients following surgery, however there was no significant difference in pancreatic exocrine status on the basis of symptoms.Conclusions: Frey’s procedure is very effective in pain control in properly selected patients of chronic calcific pancreatitis, and it also improves nutritional status of patient. Frey’s procedure might improve patient exocrine and endocrine status but further  multicentre studies are needed to come to a conclusion.

Prediction of Formation Conditions of Gas Hydrates Using Machine Learning and Genetic Programming

The formation of gas hydrates in the pipelines of oil, gas, chemical, and other industries has been a significant problem for many years because the formation of gas hydrates may block the pipelines. Hence, the knowledge of the phase equilibrium conditions of gas hydrate became necessary for the economic and safe working of oil, gas, chemical industries. Various thermodynamic approaches with various mathematical techniques are available for the prediction of formation conditions of gas hydrates. In this chapter, the authors have discussed the least square support vector machine and artificial neural network models for the prediction of stability conditions of gas hydrates and the use of genetic programming (GP) and genetic algorithm (GA) to develop a generalized correlation for predicting equilibrium conditions of gas hydrates

Safety verification of asynchronous pushdown systems with shaped stacks

In this paper, we study the program-point reachability problem of concurrent pushdown systems that communicate via unbounded and unordered message buffers. Our goal is to relax the common restriction that messages can only be retrieved by a pushdown process when its stack is empty. We use the notion of partially commutative context-free grammars to describe a new class of asynchronously communicating pushdown systems with a mild shape constraint on the stacks for which the program-point coverability problem remains decidable. Stacks that fit the shape constraint may reach arbitrary heights; further a process may execute any communication action (be it process creation, message send or retrieval) whether or not its stack is empty. This class extends previous computational models studied in the context of asynchronous programs, and enables the safety verification of a large class of message passing programs

5-Exo-dig, 5-exo-trig cascade radical cyclisation on sugar-furanose templates: entry to angularly fused oxa-and dioxa-triquinane skeletons

Serial radical cyclisation on sugar-furanose templates to create angularly fused oxa- and dioxa-triquinane skeletons has been described, the salient feature of this approach being to incipiently generate a tertiary radical from cyclopropylmethyl bromide with simultaneous release of allyl group and to subsequently incorporate it in the triquinane system

Model checking time-constrained scenario-based specifications

We consider the problem of model checking message-passing systems with real-time requirements. As behavioural specifications, we use message sequence charts (MSCs) annotated with timing constraints. Our system model is a network of communicating finite state machines with local clocks, whose global behaviour can be regarded as a timed automaton. Our goal is to verify that all timed behaviours exhibited by the system conform to the timing constraints imposed by the specification. In general, this corresponds to checking inclusion for timed languages, which is an undecidable problem even for timed regular languages. However, we show that we can translate regular collections of time-constrained MSCs into a special class of event-clock automata that can be determinized and complemented, thus permitting an algorithmic solution to the model checking problem

Optical Property Evaluation of Next Generation Thermal Control Coatings

Next generation white thermal control coatings were developed via the Small Business Innovative Research program utilizing lithium silicate chemistry as a binder. Doping of the binder with additives yielded a powder that was plasma spray capable and that could be applied to light weight polymers and carbon-carbon composite surfaces. The plasma sprayed coating had acceptable beginning-of-life and end-of-live optical properties, as indicated by a successful 1.5 year exposure to the space environment in low Earth orbit. Recent studies also showed the coating to be durable to simulated space environments consisting of 1 keV and 10 keV electrons, 4.5 MeV electrons, and thermal cycling. Large scale deposition was demonstrated on a polymer matrix composite radiator panel, leading to the selection of the coating for use on the Gravity Recovery And Interior Laboratory (GRAIL) mission