5,837 research outputs found

    Dissipation-managed soliton in a quasi-one-dimensional Bose-Einstein condensate

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    We use the time-dependent mean-field Gross-Pitaevskii equation to study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-one-dimensional Bose-Einstein condensate (BEC). Because of three-body recombination of bosonic atoms to molecules, atoms are lost (dissipated) from a BEC. Such dissipation leads to the decay of a BEC soliton. We demonstrate by a perturbation procedure that an alimentation of atoms from an external source to the BEC may compensate for the dissipation loss and lead to a dynamically-stabilized soliton. The result of the analytical perturbation method is in excellent agreement with mean-field numerics. It seems possible to obtain such a dynamically-stabilized BEC soliton without dissipation in laboratory.Comment: 5 pages, 3 figure

    A Prospective Analysis of Adverse Drug Reactions in a South Indian Hospital

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    Adverse drug reactions are a great cause of concern to the medical profession, the patients and the pharmaceutical industry. However ADR reporting and monitoring is yet to catch up in India. Hence we undertook a study to record and analyze adverse reactions among all patients admitted to the medical wards of a tertiary care. Centre patients admitted to all medical wards over one year were assessed for ADRs throughout their admission. Suspected ADRs were recorded and analyzed for i) the type of reaction ii) severity iii) Consequence on treatment that is if the drug was continued, or stopped, or needed to be treated with other drugs, iv) Physiological system involved and the v) group of the drugs associated with ADRs. Among 1250 patients admitted during the study period, 250 adverse events were observed. Majority (76.8%) were of mild type, 66% were severe requiring intensive care and 3 patients died. Antimicrobials were responsible for maximum (42.4%) ADRs followed by drugs acting on CNS (20%). When we analyzed the systems affected, CNS side effects were more common in our study. While in many other studies Cardiovascular and gastrointestinal side effects were the most common. Combination of drugs was responsible for a large percentage of ADRs. Inadvertent use of antipsychotics with sedatives led to respiratory failure in 4 patients of which 1 died. Contaminated IV fluids are suspected to be the cause of death in another fatal ADR. In conclusion there is a need for vigilant ADR monitoring to be done by all doctors to prevent morbidity and mortality from ADRs

    Dynamics of gap solitons in a dipolar Bose-Einstein condensate on a three-dimensional optical lattice

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    We suggest and study the stable disk- and cigar-shaped gap solitons of a dipolar Bose-Einstein condensate of 52^{52}Cr atoms localized in the lowest band gap by three optical-lattice (OL) potentials along orthogonal directions. The one-dimensional version of these solitons of experimental interest confined by an OL along the dipole moment direction and harmonic traps in transverse directions is also considered. Important dynamics of (i) breathing oscillation of a gap soliton upon perturbation and (ii) dragging of a gap soliton by a moving lattice along axial zz direction demonstrates the stability of gap solitons. A movie clip of dragging of three-dimensional gap soliton is included.Comment: To see the dragging movie clip please download sourc

    More Communication with Less Entanglement

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    We exhibit the intriguing phenomena of "Less is More" using a set of multipartite entangled states. We consider the quantum communication protocols for the {\em exact} teleportation, superdense coding, and quantum key distribution. We find that sometimes {\em less} entanglement is {\em more} useful. To understand this phenomena we obtain a condition that a resource state must satisfy to communicate a nn-qubit pure state with mm terms. We find that the an appropriate partition of the resource state should have a von-Neumann entropy of log2m{\rm log}_{2} m. Furthermore, it is shown that some states may be suitable for exact superdense coding, but not for exact teleportation.Comment: 7 pages, 1 tabl

    Study to Assess the Prevalence of Soft Drinking and its Determinants among the School going Children of Gwalior city

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    Background: Over the time there has been spectrum of changes in the universe. It may be at physical, chemical and cultural level. People have adopted newer life styles like their working style, clothing’s, food habits and so on. One of the pertinent example of this newer food habits is rising consumption of soft drinks rather than traditional home made drinks. This study was aimed to find out various determinants responsible for this rising trend of soft drinking so that effective intervention can be undertaken to overcome this creeping problem. Objectives: To find out the prevalence of soft drinking consumption among the students and to assess the determinants of soft drink consumption among the students. Materials and methods: It was a cross sectional study. A sample of 200 students was selected from the both govt. and private schools by stratified random sampling. Then they all were interviewed by using pre tested, semi structured proforma. Later on data was analyzed manually and by using suitable statistical software. Results: Frequent drinking of soft drinks was found more among the students of private schools than govt. (p < 0.05). A significant association was found between pocket money, TV watching and frequency of soft drinking (p< 0.05).Other reasons which were found to be responsible by far for frequent soft drinking like lack of awareness regarding hazards, frequent TV watching, desire of new taste, lack of health education from the parents side etc. Conclusion: Soft drinking consumption is creeping day by day amongst the children with out knowing their hazards. And they are the future of any country so there should be effective intervention from both sides govt. as well as parents to get rid of it at earliest

    Dynamics of quasi-one-dimensional bright and vortex solitons of a dipolar Bose-Einstein condensate with repulsive atomic interaction

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    By numerical and variational analysis of the three-dimensional Gross-Pitaevskii equation we study the formation and dynamics of bright and vortex-bright solitons in a cigar-shaped dipolar Bose-Einstein condensate for large repulsive atomic interactions. Phase diagram showing the region of stability of the solitons is obtained. We also study the dynamics of breathing oscillation of the solitons as well as the collision dynamics of two solitons at large velocities. Two solitons placed side-by-side at rest coalesce to form a stable bound soliton molecule due to dipolar attraction.Comment: To obtain the included video clips S1, S2, S3 and S4, please download sourc
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