Nonlinear optical properties of push–pull polyenes for electro-optics

Improved nonlinear organic chromophores of varying conjugation length with either thiobarbituric acid or 3-dicyanomethylene-2,3-dihydrobenzothiophene-1,1-dioxide (FORON® Blue) acceptors have been synthesized and investigated for their nonlinear optical properties. Very large quadratic hyperpolarizabilities β(−2ω; ω, ω) have been found, up to 25,700×10^(−48) esu at λ=1.91 μm. In a guest–host polymer very high electro-optic (EO) coefficients, of up to 55 pm/V, have been determined at λ=1.31 μm with 20-wt % chromophore loading. We find good agreement between molecular parameters evaluated by electric-field-induced second-harmonic generation (EFISH) and the measurements of guest–host solid–solid solutions. The latter method is well suited to the determination of the product of dipole moment μ and hyperpolarizability β quickly and reliably at the wavelength of interest for EO applications without the complications associated with EFISH measurements

Is fall prevention by vitamin D mediated by a change in postural or dynamic balance?

Introduction: The objectives were:(1) to validate a quantitative balance assessment method for fall risk prediction; (2) to investigate whether the effect of vitamin D and calcium on the risk of falling is mediated through postural or dynamic balance, as assessed by this method. Materials and methods: A secondary analysis of a double blind randomized controlled trial was employed, which included 64 institutionalized elderly women with complete balance assessment (age range: 65-97; mean 25-hydroxyvitamin D levels: 16.4ng/ml (SD ±9.9). Participants received 1,200mg calcium plus 800IU cholecalciferol (n=33) or 1,200mg calcium (n=31) per day over a 3-month treatment period. Using an electronic device attached to the lower back of the participant, balance was assessed as the degree of trunk angular displacement and angular velocity during a postural task (standing on two legs, eyes open, for 20 s) and a dynamic task (get up from a standard height chair with arm rests, sit down and then stand up again and remain standing). Results: It was found that both postural and dynamic balance independently and significantly predicted the rate of falling within the 3-month follow-up. Vitamin D plus calcium reduced the rate of falls by 60% [relative risk (RR)=0.40; 95% CI: 0.17, 0.94] if compared with calcium alone. Once postural and dynamic balance were added to the regression analysis, they both attenuated the effect of vitamin D plus calcium on the rate of falls. For postural balance, the RR changed by 22% from 0.40 to 0.62 if angular displacement was added to the model, and by 9% from 0.40 to 0.49 if angular velocity was added. For dynamic balance, it changed by 1% from 0.40 to 0.41 if angular displacement was added, and by 14% from 0.40 to 0.54 if angular velocity was added. Discussion: Thus, balance assessment using trunk angular displacement is a valid method for the prediction of falls in older women. Of the observed 60% reduction in the rate of falls by vitamin D plus calcium supplementation compared with calcium alone, up to 22% of the treatment effect was explained by a change in postural balance and up to 14% by dynamic balanc

Gender-specific hip fracture risk in community-dwelling and institutionalized seniors age 65years and older

Summary: In this study of acute hip fracture patients, we show that hip fracture rates differ by gender between community-dwelling seniors and seniors residing in nursing homes. While women have a significantly higher rate of hip fracture among the community-dwelling seniors, men have a significantly higher rate among nursing home residents. Introduction: Differences in gender-specific hip fracture risk between community-dwelling and institutionalized seniors have not been well established, and seasonality of hip fracture risk has been controversial. Methods: We analyzed detailed data from 1,084 hip fracture patients age 65years and older admitted to one large hospital center in Zurich, Switzerland. In a sensitivity analysis, we extend to de-personalized data from 1,265 hip fracture patients from the other two large hospital centers in Zurich within the same time frame (total n = 2,349). The denominators were person-times accumulated by the Zurich population in the corresponding age/gender/type of dwelling stratum in each calendar season for the period of the study. Results: In the primary analysis of 1,084 hip fracture patients (mean age 85.1years; 78% women): Among community-dwelling seniors, the risk of hip fracture was twofold higher among women compared with men (RR = 2.16; 95% CI, 1.74-2.69) independent of age, season, number of comorbidities, and cognitive function; among institutionalized seniors, the risk of hip fracture was 26% lower among women compared with men (RR = 0.77; 95% CI: 0.63-0.95) adjusting for the same confounders. In the sensitivity analysis of 2,349 hip fracture patients (mean age 85.0years, 76% women), this pattern remained largely unchanged. There is no seasonal swing in hip fracture incidence. Conclusion: We confirm for seniors living in the community that women have a higher risk of hip fracture than men. However, among institutionalized seniors, men are at higher risk for hip fracture

Leading-order QCD Analysis of Neutrino-Induced Dimuon Events

The results of a leading-order QCD analysis of neutrino-induced charm production are presented. They are based on a sample of 4111 \numu- and 871 \anumu-induced opposite-sign dimuon events with $E_{\mu 1},E_{\mu 2} > 6~{\rm GeV}$, $35 5.5\,{\rm GeV^2}$, observed in the CHARM~II detector exposed to the CERN wideband neutrino and antineutrino beams. The analysis yields the value of \linebreak the charm quark mass $m_c=1.79\pm0.38\,{\rm GeV}/c^2$ and the Cabibbo--Kobayashi--Maskawa matrix element $|V_{cd}|=0.219\pm0.016$. The strange quark content of the nucleon is found to be suppressed with respect to non-strange sea quarks by a factor $\kappa =0.39\pm0.09$

Experimental search for muonic photons

We report new limits on the production of muonic photons in the CERN neutrino beam. The results are based on the analysis of neutrino production of dimuons in the CHARM II detector. A $90\%$ CL limit on the coupling constant of muonic photons, $\alpha_{\mu} / \alpha < (1.5 \div 3.2) \times10^{-6}$ is derived for a muon neutrino mass in the range $m_{\nu_{\mu}} = (10^{-20} \div 10^5)$ eV. This improves the limit obtained from a precision measurement of the anomalous magnetic moment of the muon $(g-2)_\mu$ by a factor from 8 to 4