On Rotations as Spin Matrix Polynomials

Recent results for rotations expressed as polynomials of spin matrices are derived here by elementary differential equation methods. Structural features of the results are then examined in the framework of biorthogonal systems, to obtain an alternate derivation. The central factorial numbers play key roles in both derivations.Comment: 6 Figures. References updated in v2, along with some editing of tex

Intra-cavitary uterine pathology in women with abnormal uterine bleeding: a prospective study of 1220 women.

OBJECTIVES: Our primary aim was to assess how patients characteristics, bleeding pattern, sonographic endometrial thickness (ET) and additional features at unenhanced ultrasound examination (UTVS) and at fluid instillation sonography (FIS) contribute to the diagnosis of intracavitary uterine pathology in women presenting with abnormal uterine bleeding (AUB). We further aimed to report the prevalence of pathology in women presenting with AUB. METHODS: 1220 consecutive women presenting with AUB underwent UTVS, colour Doppler imaging (CDI) and FIS. Most women (n = 1042) had histological diagnosis. RESULTS: Mean age was 50 years and 37% were postmenopausal. Of 1220 women 54% were normal, polyps were diagnosed in 26%, intracavitary fibroids in 11%, hyperplasia without atypia in 4% and cancer in 3%. All cancers were diagnosed in postmenopausal (7%) or perimenopausal (1%) women. ET had a low predictive value in premenopausal women (LR+ and LR- of 1.34 and 0.74, respectively), while FIS had a LR+ and LR- of 6.20 and 0.24, respectively. After menopause, ET outperformed all patient characteristics for the prediction of endometrial pathology (LR+ and LR- of 3.13 and 0.24). The corresponding LR+ and LR- were 10.85 and 0.71 for CDI and 8.23 and 0.26 for FIS. CONCLUSION: About half of the women presenting to a bleeding clinic will have pathology. In premenopausal women, benign lesions are often the cause of AUB. For the prediction of intracavitary pathology ET is of little value in premenopausal women. CDI and FIS substantially improve the diagnostic accuracy

IP Eri: A surprising long-period binary system hosting a He white dwarf

We determine the orbital elements for the K0 IV + white dwarf (WD) system IP Eri, which appears to have a surprisingly long period of 1071 d and a significant eccentricity of 0.25. Previous spectroscopic analyses of the WD, based on a distance of 101 pc inferred from its Hipparcos parallax, yielded a mass of only 0.43 M$_\odot$, implying it to be a helium-core WD. The orbital properties of IP Eri are similar to those of the newly discovered long-period subdwarf B star (sdB) binaries, which involve stars with He-burning cores surrounded by extremely thin H envelopes, and are therefore close relatives to He WDs. We performed a spectroscopic analysis of high-resolution spectra from the HERMES/Mercator spectrograph and concluded that the atmospheric parameters of the K0 component are $T_{\rm eff} = 4960$ K, $\log{g} = 3.3$, [Fe/H] = 0.09 and $\xi = 1.5$ km/s. The detailed abundance analysis focuses on C, N, O abundances, carbon isotopic ratio, light (Na, Mg, Al, Si, Ca, Ti) and s-process (Sr, Y, Zr, Ba, La, Ce, Nd) elements. We conclude that IP Eri abundances agree with those of normal field stars of the same metallicity. The long period and non-null eccentricity indicate that this system cannot be the end product of a common-envelope phase; it calls instead for another less catastrophic binary-evolution channel presented in detail in a companion paper (Siess et al. 2014).Comment: 14 pages, 10 figures, 4 tables, accepted for publication in A&A (Update of Table 3, Fig. 8 and text in Sect. 5.1, 5.3 and 6 due to minor corrections on N and Y II

The dynamics of a low-order coupled ocean-atmosphere model

A system of five ordinary differential equations is studied which combines the Lorenz-84 model for the atmosphere and a box model for the ocean. The behaviour of this system is studied as a function of the coupling parameters. For most parameter values, the dynamics of the atmosphere model is dominant. For a range of parameter values, competing attractors exist. The Kaplan-Yorke dimension and the correlation dimension of the chaotic attractor are numerically calculated and compared to the values found in the uncoupled Lorenz model. In the transition from periodic behaviour to chaos intermittency is observed. The intermittent behaviour occurs near a Neimark-Sacker bifurcation at which a periodic solution loses its stability. The length of the periodic intervals is governed by the time scale of the ocean component. Thus, in this regime the ocean model has a considerable influence on the dynamics of the coupled system.Comment: 20 pages, 15 figures, uses AmsTex, Amssymb and epsfig package. Submitted to the Journal of Nonlinear Scienc

Need for narrative

What do consumers need from a narrative? How can videographers satisfy those needs? Through semi-structured interviews with 55 Eurostar passengers from 14 countries, this film documents how people define narratives, why they need them, and how they experience the effects of need for narrative. The adjoining commentary contributes to the development of videography as an attractive method by introducing the videographer’s perspective and elucidating key story elements that can help satisfy viewers’ needs for narrative. The suggested approach maintains the vivid quality of videography and respects its methodological rigour, while increasing its effectiveness in close alignment with a consumer society that visual communication increasingly permeates. As such, the commentary and the film jointly unveil videographers’ etic and viewers’ emic use and evaluation of the videographic method

Entangling ability of a beam splitter in the presence of temporal which-path information

We calculate the amount of polarization-entanglement induced by two-photon interference at a lossless beam splitter. Entanglement and its witness are quantified respectively by concurrence and the Bell-CHSH parameter. In the presence of a Mandel dip, the interplay of two kinds of which-path information -- temporal and polarization -- gives rise to the existence of entangled polarization-states that cannot violate the Bell-CHSH inequality.Comment: 8 pages including 2 figure

Thin-layer chromatography of pigments from reaction center particles of Rhodopseudomonas spheroides

1. Pigments extracted from reaction center particles of Rhodopseudomonas spheroides were separated and identified by means of thin-layer chromatography.\ud \ud 2. The results strongly suggest that bacteriochlorophyll a is the only bacteriochlorophyll pigment present in reaction centers.\ud \ud 3. Other compounds identified are bacteriopheophytin a, ubiquinone-10 and spheroidene

Spin resonance in EuTiO3 probed by time-domain GHz ellipsometry

We show an example of a purely magnetic spin resonance in EuTiO3 and the resulting new record high Faraday rotation of 590 deg/mm at 1.6 T for 1 cm wavelengths probed by a novel technique of magneto-optical GHz time-domain ellipsometry. From our transmission measurements of linear polarized light we map out the complex index of refraction in the GHz to THz range. We observe a strong resonant absorption by magnetic dipole transitions involving the Zeeman split S=7/2 magnetic energy levels of the Eu 2+ ions, which causes a very large dichroism for circular polarized radiation.Comment: 4 pages, 4 figure