Nonlinear compression of temporal solitons in an optical waveguide via inverse engineering

We propose a novel method based on the so-called shortcut to adiabatic passage techniques to achieve fast compression of temporal solitons in a nonlinear waveguide. We demonstrate that soliton compression could be achieved, in principle, at an arbitrarily small distance by inverse engineering the pulse width and the nonlinearity of the medium. The proposed scheme could possibly be exploited for various short-distance communication protocols and may be even in nonlinear guided wave-optics devices and generation of ultrashort soliton pulses

Distinct stick-slip modes in adhesive polymer interfaces

Stick-slip, manifest as intermittent tangential motion between two solids, is a well-known friction instability that occurs in a number of natural and engineering systems. In the context of adhesive polymer interfaces, this phenomenon has often been solely associated with Schallamach waves, which are termed slow waves due to their low propagation speeds. We study the dynamics of a model polymer interface using coupled force measurements and high speed \emph{in situ} imaging, to explore the occurrence of stick-slip linked to other slow wave phenomena. Two new waves---slip pulse and separation pulse---both distinct from Schallamach waves, are described. The slip pulse is a sharp stress front that propagates in the same direction as the Schallamach wave, while the separation pulse involves local interface detachment and travels in the opposite direction. Transitions between these stick-slip modes are easily effected by changing the sliding velocity or normal load. The properties of these three waves, and their relation to stick-slip is elucidated. We also demonstrate the important role of adhesion in effecting wave propagation.Comment: 22 pages, 9 figure

A new deterministic model of strange stars

The observed evidence for the existence of strange stars and the concomitant observed masses and radii are used to derive an interpolation formula for the mass as a function of the radial coordinate. The resulting general mass function becomes an effective model for a strange star. The analysis is based on the MIT bag model and yields the energy density, as well as the radial and transverse pressures. Using the interpolation function for the mass, it is shown that a mass-radius relation due to Buchdahl is satisfied in our model. We find the surface redshift ($Z$) corresponding to the compactness of the stars. Finally, from our results, we predict some characteristics of a strange star of radius 9.9 km.Comment: one new figures and minor revisions have been done. To appear in Eur.Phys.J.

Basic Relevant Theories for Combinators at Levels I and II

The system B+ is the minimal positive relevant logic. B+ is trivially extended to B+T on adding a greatest truth (Church constant) T. If we leave ∨ out of the formation apparatus, we get the fragment B∧T. It is known that the set of ALL B∧T theories provides a good model for the combinators CL at Level-I, which is the theory level. Restoring ∨ to get back B+T was not previously fruitful at Level-I, because the set of all B+T theories is NOT a model of CL. It was to be expected from semantic completeness arguments for relevant logics that basic combinator laws would hold when restricted to PRIME B+T theories. Overcoming some previous difficulties, we show that this is the case, at Level I. But this does not form a model for CL. This paper also looks for corresponding results at Level-II, where we deal with sets of theories that we call propositions. We adapt work by Ghilezan to note that at Level-II also there is a model of CL in B∧T propositions. However, the corresponding result for B+T propositions extends smoothly to Level-II only in part. Specifically, only some of the basic combinator laws are proved here. We accordingly leave some work for the reader.&nbsp

A study of the role of intervention in the final outcome of acute pancreatitis

Background: Acute pancreatitis is a common disease which varies in severity, from mild self-limiting pancreatic inflammation to severe pancreatic necrosis with life-threatening sequelae. As per the recent recommendations early intensive care with delayed intervention and step-up approach when indicated has definite survival advantages over the risks associated with early surgical procedures. The present study was aimed at evaluating the mortality and morbidity risk in patients undergoing procedural intervention in acute pancreatitis.Methods: This was a prospective study done in Sri Ramachandra Medical College and Hospital from April 2012- September 2014. All patients with a diagnosis of acute pancreatitis were included in this study. A total of 110 patients were analysed. Routine lab parameters, serum amylase, lipase, lipid profile, calcium, CRP, LDH, CT abdomen, CXR and 2D Echo was done for all patients. Procedural intervention was planned as per the guidelines.Results: Patients were given early intensive care as per the initial severity scores. 25 patients required intervention. Serum LDH, amylase, lipase and CT severity index were better predictors of requirement of intervention and death. Open necrosectomy was done in 15 patients (13.6%), laparoscopic necrosectomy in 3 patients (2.7%) and step up approach was tried in 7 patients (6.4%). Patients who were tried step up approach were monitored closely for any deterioration in their clinical condition to decide about surgery. 7 out of 8 patients who underwent surgery died.  Alcoholic pancreatitis that underwent intervention had a high risk of mortality.Conclusions: Intensive care monitoring with delayed intervention had a better survival benefit. Patients subjected to minimally invasive interventions had a better chance of survival.

3′-sulfated LewisA/C: An oncofetal epitope associated with metaplastic and oncogenic plasticity of the gastrointestinal foregut

Metaplasia, dysplasia, and cancer arise from normal epitheli