20,433 research outputs found

    Prevalence, Reasons for Use, and Risk Perception of Electronic Cigarettes among Post-Acute Coronary Syndrome Smokers

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    Purpose—The use of electronic cigarettes (e-cigarettes) has risen dramatically in recent years. However, there is currently no published data on use of e-cigarettes among cardiac patients. The current study reports on the prevalence, reasons for use, and perceived risks of e-cigarettes among post-Acute Coronary Syndrome (ACS) patients. The relationship between e-cigarette use and post- ACS tobacco smoking cessation is also explored. Methods—Participants were drawn from a randomized trial of smoking cessation treatments following hospitalization for ACS. The current study focuses on 49 participants that completed e- cigarette questions at 24 weeks post-ACS. Results—51.0% of participants reported ever use of an e-cigarette and 26.5% reported using an e-cigarette at some time during the 24 weeks post-ACS. Ever use and post-ACS use were both significantly associated with lower rates of abstinence from tobacco cigarettes. Participants perceived e-cigarettes as less harmful to cardiac health than tobacco use and Chantix, and similarly harmful as nicotine replacement therapy. Participant perceived likelihood of experiencing a heart attack in the next year was 34.6% if they were to regularly use e-cigarettes only, significantly lower than perceived risk of recurrence if they were to regularly smoke only tobacco cigarettes (56.2%) and significantly higher than perceived risk of recurrence if they were to use no nicotine (15.2%). Conclusions—A significant minority of patients are using e-cigarettes post-ACS. Providers should be prepared to discuss potential discrepancies between patient beliefs about the safety of e- cigarettes and the current state of the science

    Localized quantum walks as secured quantum memory

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    We show that a quantum walk process can be used to construct and secure quantum memory. More precisely, we show that a localized quantum walk with temporal disorder can be engineered to store the information of a single, unknown qubit on a compact position space and faithfully recover it on demand. Since the localization occurss with a finite spread in position space, the stored information of the qubit will be naturally secured from the simple eavesdropper. Our protocol can be adopted to any quantum system for which experimental control over quantum walk dynamics can be achieved.Comment: 7 pages, 4 figure

    The Yagita invariant of symplectic groups of large rank

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    Fix a prime pp, and let RR be any subring of the complex numbers that is either integrally closed or contains a primitive ppth root of 1. For each np1n\geq p-1 we compute the Yagita invariant at the prime pp for the symplectic group Sp(2n,R)Sp(2n,R).Comment: Minor changes compared to first versio

    Non-disturbing quantum measurements

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    We consider pairs of quantum observables (POVMs) and analyze the relation between the notions of non-disturbance, joint measurability and commutativity. We specify conditions under which these properties coincide or differ---depending for instance on the interplay between the number of outcomes and the Hilbert space dimension or on algebraic properties of the effect operators. We also show that (non-)disturbance is in general not a symmetric relation and that it can be decided and quantified by means of a semidefinite program.Comment: Minor corrections in v

    Pairing of a harmonically trapped fermionic Tonks-Girardeau gas

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    The fermionic Tonks-Girardeau (FTG) gas is a one-dimensional spin-polarized Fermi gas with infinitely strong attractive zero-range odd-wave interactions, arising from a confinement-induced resonance reachable via a three-dimensional p-wave Feshbach resonance. We investigate the off-diagonal long-range order (ODLRO) of the FTG gas subjected to a longitudinal harmonic confinement by analyzing the two-particle reduced density matrix for which we derive a closed-form expression. Using a variational approach and numerical diagonalization we find that the largest eigenvalue of the two-body density matrix is of order N/2, where N is the total particle number, and hence a partial ODLRO is present for a FTG gas in the trap.Comment: 4 pages, 3 figures, revtex

    Maintaining Quantum Coherence in the Presence of Noise through State Monitoring

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    Unsharp POVM measurements allow the estimation and tracking of quantum wavefunctions in real-time with minimal disruption of the dynamics. Here we demonstrate that high fidelity state monitoring, and hence quantum control, is possible even in the presence of classical dephasing and amplitude noise, by simulating such measurements on a two-level system undergoing Rabi oscillations. Finite estimation fidelity is found to persist indefinitely long after the decoherence times set by the noise fields in the absence of measurement.Comment: 5 pages, 4 figure

    Sensory acceptance of organic and conventional food by children in the age of 2 to 7 years

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    This study is initialized to find out which sensory factors might influence the acceptance of organic food by young children. 138 children aged from 2 to 7 years were recruited at the German Research Institute of Child Nutrition in Dortmund. All these children are participating in the DONALD-Study. Detailed nutrition records are available about breastfeeding and feeding of these children from birth to the age of one and further on. In a 2-year testing-period children tasted organic and conventional food in two-sided Paired Comparison Tests. In both years parents were asked a number of questions, mainly about the nutrition behaviour of their children. Sensory tests were analyzed and connected in different ways: with data of sensory profiles, nutrition records and different questionnaires
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