99 research outputs found

    Dissipative Tunneling in 2 DEG: Effect of Magnetic Field, Impurity and Temperature

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    We have studied the transport process in the two dimensional electron gas (2DEG) in presence of a magnetic field and a dissipative environment at temperature T. By means of imaginary time series functional integral method we calculate the decay rates at finite temperature and in the presence of dissipation. We have studied decay rates for wide range of temperatures -- from the thermally activated region to very low temperature region where the system decays by quantum tunneling. We have shown that dissipation and impurity helps the tunneling. We have also shown that tunneling is strongly affected by the magnetic field. We have demonstrated analytical results for all the cases mentioned above.Comment: 8 pages, 2 figure

    Quantum physics meets biology

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    Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the last decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world view of quantum coherences, entanglement and other non-classical effects, has been heading towards systems of increasing complexity. The present perspective article shall serve as a pedestrian guide to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future quantum biology, its current status, recent experimental progress and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.Comment: 26 pages, 4 figures, Perspective article for the HFSP Journa

    PT-symetrically regularized Eckart,Poeschl-Teller and Hulthen potentials

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    Version 1: The well known Eckart's singular s-wave potential is PT-symmetrically regularized and continued to the whole real line. The new model remains exactly solvable and its bound states remain proportional to Jacobi polynomials. Its real and discrete spectrum exhibits several unusual features. Version 2: Parity times time-reversal symmetry of complex Hamiltonians with real spectra is usually interpreted as a weaker mathematical substitute for Hermiticity. Perhaps an equally important role is played by the related strengthened analyticity assumptions. In a constructive illustration we complexify a few potentials solvable only in s-wave. Then we continue their domain from semi-axis to the whole axis and get the new exactly solvable models. Their energies come out real as expected. The new one-dimensional spectra themselves differ quite significantly from their s-wave predecessors.Comment: Original 10-page letter ``PT-symmetrized exact solution of the singular Eckart oscillator" is extended to a full pape

    Nigellissima: A Study of Glamour, Performativity and Embodiment

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    This is a study of glamour, its complexities and its relationship with and role within celebrity culture. We explore glamour in the context of Nigella, the London-born TV cook, food writer and self-proclaimed ‘domestic goddess’ of British culinary culture. In our study we consider the interconnections between glamour, specifically Italian-style retro-glamour, and performativity in Nigella’s career. We also address the role of embodiment and authenticity in the masquerade of femininity. Our analysis focuses on Nigella’s glamour over time, considering its creation, enactment and reaffirmation following scandal. We conclude by speculating on glamour’s complex and ambivalent relationship with celebrity culture, and the role of vulnerability in creating authentic and enduring glamour in contemporary consumer society

    The design of a community lifestyle programme to improve the physical and psychological well-being of pregnant women with a BMI of 30 kg/m2 or more

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    <p>Abstract</p> <p>Background</p> <p>Obesity is a global public health issue. Having a BMI of 30 kg/m<sup>2 </sup>or more (classifying a person as obese) at the start of pregnancy is a significant risk factor for maternal and fetal morbidity. There is a dearth of evidence to inform suitable inteventions to support pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more. Here we describe a study protocol to test the feasibility of a variety of potential healthy lifestyle interventions for pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more in a community based programme.</p> <p>Methods/Design</p> <p>Four hundred women will be approached to attend a 10-week community lifestyle programme. The programme will be provided as a supplement to standard antenatal care. The programme is multi-faceted, aimed at equipping participants with the skills and knowledge needed to adopt healthy behaviours. The social (cognitive) learning theory will be used as a tool to encourage behaviour change, the behaviour change techniques are underpinned by five theoretical components; self-efficacy, outcome expectancies, goal setting, feedback and positive reinforcement.</p> <p>The main outcomes are pregnancy weight gain and caesarean section rate. Other important outcomes include clinical outcomes (e.g., birth weight) and psychological outcomes (e.g., well-being). Secondary outcomes include women's experience of pregnancy and health care services, amount of physical activity, food intake and the suitability of the intervention components.</p> <p>A prospective study using quantitative and qualitative methods will inform the feasibility of implementing the community lifestyle programme with pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more. Mixed methods of data collection will be used, including diaries, focus groups/interviews, pedometers, validated and specifically designed questionnaires, a programme register, weight gain during pregnancy and perinatal outcome data.</p> <p>Discussion</p> <p>Findings from this current feasibility study will inform future interventions and NHS services and add to the evidence-base by providing information about the experiences of pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more undertaking a community lifestyle programme. The study will lead on to a randomised control trial of a suitable intervention to improve the pregnancy outcomes of this target group.</p> <p>Trail Registration</p> <p>ISRCTN29860479.</p
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