4,289 research outputs found

    Feshbach resonances and collapsing Bose-Einstein condensates

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    We investigate the quantum state of burst atoms seen in the recent Rb-85 experiments at JILA. We show that the presence of a resonance scattering state can lead to a pairing instability generating an outflow of atoms with energy comparable to that observed. A resonance effective field theory is used to study this dynamical process in an inhomogeneous system with spherical symmetry

    Assessment of the face validity, feasibility and utility of a patient-completed questionnaire for polymyalgia rheumatica: a postal survey using the QQ-10 questionnaire.

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    BACKGROUND: The development of a patient-reported outcome measure (PROM) for polymyalgia rheumatica (PMR), a condition that causes pain, stiffness and disability, is necessary as there is no current validated disease-specific measure. Initial literature synthesis and qualitative research established a conceptual framework for the condition along with a list of symptoms and effects of PMR that patients felt were important to them. These findings were used to derive the candidate items for a patient-completed questionnaire. We aim to establish the face validity of this initial "long form" of a PROM. METHODS: People with a current or previous diagnosis of PMR were recruited both from the community and from rheumatology clinics. They were asked to complete the PMR questionnaire along with the QQ-10 questionnaire, which is a measure used to assess the face validity, feasibility and utility of patient healthcare questionnaires. RESULTS: A total of 28 participants with an age range of 59-85 years and a length of time since diagnosis from 4 months to 18 years completed the QQ-10. The overall mean "value" score was 79% (SD 12), and the mean "burden" score was 21% (SD 18). The free-text comments were analysed thematically and were found to focus on layout, content, where in the clinical pathway the questionnaire would be most beneficial, specific items missing and other areas for consideration. CONCLUSIONS: The high mean value score and low burden score indicate that the questionnaire has good face validity and is acceptable to patients. The questionnaire now needs to undergo further psychometric evaluation and refinement to develop the final tool for use in clinical practice and research

    Hormone replacement therapy after surgery for stage 1 or 2 cutaneous melanoma

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    A total of 206 women were followed for a minimum of 5 years after primary melanoma surgery to establish if hormone replacement therapy (HRT) adversely affected prognosis. In all, 123 had no HRT and 22 have died of melanoma; 83 had HRT for varying periods and one has died of melanoma. After controlling for known prognostic factors, we conclude that HRT after melanoma does not adversely affect prognosis

    Superposition of macroscopic numbers of atoms and molecules

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    We theoretically examine photoassociation of a non-ideal Bose-Einstein condensate, focusing on evidence for a macroscopic superposition of atoms and molecules. This problem raises an interest because, rather than two states of a given object, an atom-molecule system is a seemingly impossible macroscopic superposition of different objects. Nevertheless, photoassociation enables coherent intraparticle conversion, and we thereby propose a viable scheme for creating a superposition of a macroscopic number of atoms with a macroscopic number of molecules.Comment: 4 pages, 2 figs, to appear in Phys. Rev. Let

    Landau-Zener Problem for Trilinear Hamiltonians

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    We consider a nonlinear version of the Landau-Zener problem, focusing on photoassociation of a Bose-Einstein condensate as a specific example. Contrary to the exponential rate dependence obtained for the linear problem, a series expansion technique indicates that, when the resonance is crossed slowly, the probability for failure of adiabaticity is directly proportional to the rate at which the resonance is crossed.Comment: 4.5 pages, 1 figure, transferred to PRA; v2 adds discussion, clarification, and explicit numbers for Na and 87R

    Melanoma incidence and mortality in Scotland 1979–2003

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    We studied 12 450 cases of invasive melanoma diagnosed in Scotland in 1979–2003, by thickness, pathological type, and body site at ages under 40, 40–59, and 60 years and over. Melanoma incidence trebled in males from 3.57 to 10.93/105 per year, and increased 2.3-fold in females from 5.60 to 12.96/105 per year. The rate of increase fell in each successive 5-year period. The greatest increase was in males aged 60 years and over at diagnosis. Significant incidence increases were seen in melanomas <1 mm in all three age groups, but those >4 mm only increased significantly at ages 60 years and over. All histological types increased significantly at ages 60 years and over, and in this age group the greatest increase was seen on the head and neck. Five-year disease-free survival improved steadily. Survival figures for 1994–1998 ranged from 93.6% for males and 95.8% for females with tumours <1 mm, to 52.4 and 48.3%, respectively, for those with tumours >4 mm. Over the 25 years, melanoma mortality doubled in males from 1.1 to 2.4/105 per year, but was unchanged in females at 1.5/105 per year. Public education on melanoma is required both for primary prevention and earlier diagnosis, particularly for older males
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