60 research outputs found

    Multiple scattering of photons by atomic hyperfine multiplets

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    Mesoscopic interference effects in multiple scattering of photons depend crucially on the internal structure of the scatterers. In the present article, we develop the analytical theory of multiple photon scattering by cold atoms with arbitrary internal hyperfine multiplets. For a specific application, we calculate the enhancement factor of elastic coherent backscattering as a function of detuning from an entire hyperfine multiplet of neighboring resonances that cannot be considered isolated. Our theory permits to understand why atoms behave differently from classical Rayleigh point-dipole scatterers, and how the classical description is recovered for larger but still microscopic objects like molecules or clusters.Comment: minor changes, published versio

    Menopausal Quality of Life: A RCT of Yoga, Exercise and Omega-3 Supplements

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    Objective— Determine efficacy of three non-hormonal therapies for improving menopause- related quality of life (QOL) in women with vasomotor symptoms (VMS). Methods— 12-week 3×2 randomized, controlled, factorial design trial. Peri- and postmenopausal women, ages 40-62 years, were randomized to yoga (n=107), exercise (n=106), or usual activity (n=142), and also randomized to double-blind comparison of omega-3 (n=177) or placebo (n=178) capsules. Interventions: 1) weekly 90-minute yoga classes with daily at-home practice; 2) individualized facility-based aerobic exercise training 3 times/week; and 3) 0.615 gram omega-3 supplement, 3 times/day. Outcomes: Menopausal Quality of Life Questionnaire (MENQOL) total and domain (VMS, psychosocial, physical and sexual) scores. Results— Among 355 randomized women, average age 54.7 years, 338 (95%) completed 12- week assessments. Mean baseline VMS frequency was 7.6/day and mean baseline total MENQOL score was 3.8 (range 1-8 from better to worse) with no between-group differences. For yoga compared to usual activity, baseline to 12-week improvements were seen for MENQOL total -0.3 (95% CI -0.6 to 0.0, p=0.02), and VMS (p=0.02) and sexuality (p=0.03) domain scores. For exercise and omega-3 compared to controls, improvements in baseline to 12-week total MENQOL scores were not observed. Exercise showed benefit in the MENQOL physical domain score at 12- weeks (p=0.02). Conclusion— All women become menopausal and many seek medical advice on ways to improve quality of life; little evidence-based information exists. We found, among healthy sedentary menopausal women, yoga appears to improve menopausal QOL - the clinical significance of our finding is uncertain due to modest effect

    American poetologics : statements and poems by twentieth century poets = Amerikanische Poetologie. - Zweisprachig: Englisch / Deutsch

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    Amerikanische Lyriker haben die Dichtung des 20. Jahrhunderts weltweit maßgeblich beeinflusst. Dennoch sind ihre Gedichte und erst recht ihre Äußerungen zur Poetik mit wenigen Ausnahmen in Deutschland nur spärlich rezipiert worden. Der vorliegende Band stellt die Traditionslinien und die meisten wichtigeren Dichtungsschulen von William Carlos Williams bis in die 90er Jahre (u.a. Objektivismus, Beat-, San Francisco-, Black Mountain-, New York-, Deep Image- und Language-Lyrik sowie ethnische Dichtung) anhand der Selbstäußerungen von 23 Lyrikerinnen und Lyrikern und einer kleineren Auswahl repräsentativer Gedichte vor. Erkennbar wird dabei die Vielfalt und auch die Dynamik der poetischen Produktion und Reflexion in den Vereinigten Staaten

    Perceptual consequences of changes in epilaryngeal area and shape

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    The influence of epilaryngeal area on glottal flow and the acoustic signal has been described [Titze, J. Acoust. Soc. Am. 123, 2733–2749 (2008)], but it is not known how (or whether) changes in epilaryngeal area influence perceived voice quality. This study examined these relationships in a kinematic vocal tract model. Epilaryngeal constrictions and expansions were simulated at the levels of the aryepiglottic folds and the ventricular folds in the context of four glottal configurations representing normal vibration to severe vocal fold paralysis, for the three corner vowels /a/, /i/, and /u/. Minimum and maximum glottal flow, maximum flow declination rate, spectral slope, cepstral peak prominence, and the harmonics-to-noise ratio were measured, and listeners completed a perceptual sort-and-rate task for all samples. Epilaryngeal constriction and expansion caused salient differences in voice quality. The location of constriction was also perceivable. Vowels simulated with aryepiglottic constriction demonstrated lower maximum airflow and less noise than the other epilaryngeal shapes, and listeners consistently perceived them as distinct from other stimuli. Acoustic differences decreased with increasing severity of simulated paralysis. Results of epilaryngeal constriction and expansion were similar for /a/ and /i/, and produced slightly different patterns for /u/
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