1,261 research outputs found

    Bi-directional light transmission properties assessment for venetian blinds : Computer simulations compared to photogoniometer measurements

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    An accurate evaluation of daylight distribution through advanced fenestration systems (complex glazing, solar shading systems) requires the knowledge of their Bi-directional light Transmission Distribution Function (BTDF). An innovative equipment for the experimental assessment of these bi-directional functions has been developed, based on a digital imaging detection system. An extensive set of BTDF measurements was performed with this photogoniometer on venetian blinds presenting curved slats with a mirror coating on the upper side. In this paper, the measured data are compared with ray-tracing results achieved with a virtual copy of the device, that was constructed with a commercial ray-tracing software. The model of the blind was created by implementing the measured reflection properties of the slats coatings in the ray-tracing calculations. These comparisons represent an original and objective validation methodology for detailed bi-directional properties for a complex system; the good agreement between the two methods, yet presenting very different parameters and assessment methodologies, places reliance both on the digital-imaging detection system and calibration, and on the potentiality of a flexible calculation method combining ray-tracing simulations with simple components measurements

    The prognostic significance of transforming growth factors in human breast cancer.

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    Transforming growth factor alpha (TGF alpha) and Transforming growth factor beta-1 (TGF-beta 1) are growth regulatory for breast cancer cell lines in vitro and several studies have suggested that levels of the receptor for TGF alpha, the epidermal growth factor (EGFR) in tumour biopsies predict relapse and survival. We have examined the prognostic significance of TGF alpha, TGF-beta 1 and EGFR mRNA expression in a series of patients with primary breast cancer with a median follow up period of 60 months. In 167 patients the expression of TGF-beta 1 was inversely correlated with node status (P = 0.065) but not ER status, tumour size or menopausal status. Patients with high levels of TGF-beta 1 had a longer disease free interval with a significantly longer probability of survival at 80 months although the overall relapse free survival was not increased. EGFR mRNA expression was measured in 106 patients and was inversely correlated with ER status (P = 0.018). EGFR levels did not predict for early relapse or survival. TGF alpha mRNA levels were measured in 104 patients, no correlation was seen tumour size, node status, Er status, or clinical outcome

    Effects of endocrine therapy on steroid-receptor content of breast cancer.

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    In order to determine the mechanisms of relapse following response to endocrine therapy, we have measured the oestrogen receptor (RE) content of biopsies of breast cancer in patients receiving various types of endocrine treatment. RE content fell in responding (means of 260.2 to 12 fmol/mg protein) and in nonresponding (means of 155.1 to 31.8 fmol/mg protein) patients who had measurable receptor at the start of treatment. Some of these patients, and a further group of responders to endocrine therapy, were monitored until relapse. Tumour biopsies at the time of relapse showed that 10/14 tumour samples contained significant RE (mean of 86.7 fmol/mg protein; range less than 10-271 fmol/mg protein) after successful endocrine therapy. No relationship could be found between RE content and plasma gonadotrophin or steroid-hormone concentration, but the fall in RE content correlated with reduced numbers of tumour cells in the biopsy. These results indicate that relapse following successful endocrine therapy in breast cancer does not appear to be due to the emergence of RE-negative tumour cells. The fall in RE content during response to endocrine therapy may be due to reduced tumour-cell content of the biopsy

    Evidence for a vortex-glass transition in superconducting Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2}

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    Measurements of magneto-resistivity and magnetic susceptibility were performed on single crystals of superconducting Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2} close to the conditions of optimal doping. The high quality of the investigated samples allows us to reveal a dynamic scaling behaviour associated with a vortex-glass phase transition in the limit of weak degree of quenched disorder. Accordingly, the dissipative component of the ac susceptibility is well reproduced within the framework of Havriliak-Negami relaxation, assuming a critical power-law divergence for the characteristic correlation time τ\tau of the vortex dynamics. Remarkably, the random disorder introduced by the Fe1−x_{1-x}Cox_{x} chemical substitution is found to act on the vortices as a much weaker quenched disorder than previously reported for cuprate superconductors such as, e.g., Y1−x_{1-x}Prx_{x}Ba2_{2}Cu3_{3}O7−δ_{7-\delta}.Comment: 10 pages, 8 figure

    He II λ\lambda4686 emission from the massive binary system in η\eta Car: constraints to the orbital elements and the nature of the periodic minima

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    {\eta} Carinae is an extremely massive binary system in which rapid spectrum variations occur near periastron. Most notably, near periastron the He II λ4686\lambda 4686 line increases rapidly in strength, drops to a minimum value, then increases briefly before fading away. To understand this behavior, we conducted an intense spectroscopic monitoring of the He II λ4686\lambda 4686 emission line across the 2014.6 periastron passage using ground- and space-based telescopes. Comparison with previous data confirmed the overall repeatability of EW(He II λ4686\lambda 4686), the line radial velocities, and the timing of the minimum, though the strongest peak was systematically larger in 2014 than in 2009 by 26%. The EW(He II λ4686\lambda 4686) variations, combined with other measurements, yield an orbital period 2022.7±0.32022.7\pm0.3 d. The observed variability of the EW(He II λ4686\lambda 4686) was reproduced by a model in which the line flux primarily arises at the apex of the wind-wind collision and scales inversely with the square of the stellar separation, if we account for the excess emission as the companion star plunges into the hot inner layers of the primary's atmosphere, and including absorption from the disturbed primary wind between the source and the observer. This model constrains the orbital inclination to 135∘135^\circ-153∘153^\circ, and the longitude of periastron to 234∘234^\circ-252∘252^\circ. It also suggests that periastron passage occurred on T0=2456874.4±1.3T_0 = 2456874.4\pm1.3 d. Our model also reproduced EW(He II λ4686\lambda 4686) variations from a polar view of the primary star as determined from the observed He II λ4686\lambda 4686 emission scattered off the Homunculus nebula.Comment: The article contains 23 pages and 17 figures. It has been accepted for publication in Ap
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