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[en] The main aim of this work is to understand how the prediction of the seismic performance of moment-resisting (MR) steel frames depends on the modelling of their dissipative zones when the structure geometry (number of stories and bays) and seismic excitation source vary. In particular, a parametric analysis involving 4 frames was carried out, and, for each one, the full-strength beam-to-column connections were modelled according to 4 numerical approaches with different degrees of sophistication (Smooth Hysteretic Model, Bouc-Wen, Hysteretic and simple Elastic-Plastic models). Subsequently, Incremental Dynamic Analyses (IDA) were performed by considering two different earthquakes (Spitak and Kobe). The preliminary results collected so far pointed out that the influence of the joint modelling on the overall frame response is negligible up to interstorey drift ratio values equal to those conservatively assumed by the codes to define conventional collapse (0.03 rad). Conversely, if more realistic ultimate interstorey drift values are considered for the q-factor evaluation, the influence of joint modelling can be significant, and thus may require accurate modelling of its cyclic behavior. (paper)
[en] The objectives were to generate a variety of strategies to identify alternative ways that the PV Sector can use its specific strengths to capitalize on opportunities or to avoid threats and to overcome its weaknesses. The so-called SWOT analysis provides a matrix illustrating how businesses can match the external opportunities and threats facing the sector with its internal strengths and weaknesses to yield in possible strategic alternatives. This method lends itself to brainstorming to create alternative strategies and actions, which might not otherwise be considered. In two working group meetings with participants from the PV industry, research and other stakeholders the SWOT were performed to result into implications for the PV sector. Through workshops the results will be discussed within an expert group and priorities for the future activities will be defined. The project is co-financed through the 6. Framework Programme of the EC. (authors)
[en] The objective was to develop a comprehensive strategy that answers to the need of today European PV industry. Namely: - Develop PV markets in Europe - Develop export markets. - Position the European PV industry within the European political environment and support the effort of national actors in their local objectives. This method lends itself to brainstorming to create actions and synergies, on order to achieve strategy objectives. The whole work is based on working groups clearly defined on the purpose, where all EPIA members are invited to participate. The overall first results are presented during the 19. EU PV Conference in Paris and EPIA will do recommendations on actions to be undertaken in the future. This strategy is co-financed by EPIA members and the 6. Framework Programme for research of the European Commission through the PV Catapult project. (authors)
[en] To determine whether percutaneous biopsy can safely differentiate radial scars (RS) that can be followed from those that require excision. Retrospective analysis of prospectively collected data regarding 15 986 biopsies was performed at the Centre Hospitalier de l'Universite de Montreal between October 1995 and December 2003 and yielded 227 RS. The type of biopsy, number of cores, and mammographic characteristics were recorded. Only lesions with surgical pathology or 24 months of mammographic stability were considered for analysis. Subgroup analyses were performed for patients who underwent 14-gauge core biopsy (CB), 11-gauge vacuum-assisted biopsy (VAB), or both. Among the 14-gauge CBs (n = 176), data were available for 144 (81.8%); among the 11-gauge VABs (n = 51), data were available for 40 (78.4%). Thirty lesions had 14-gauge CB followed by 11-gauge VAB. RS were associated with cancer in 19.6%, with a high-risk lesion in 20.1% and a benign lesion in 60.3%. Overall, 4% of cancers were missed (5% for 14-gauge CB and 0% for 11-gauge VAB), and cancer was underestimated in 22.2% (25% for 14-gauge CB and 16.7% for 11-gauge VAB). One (3.7%) additional cancer was found when benign radial scar on 14-gauge CB underwent subsequent 11-gauge VAB. Cancer was associated with 37% of RS presenting as masses but with only 17.1% of distortions and 12.3% of microcalcifications. If benign radial scar is found on 14-gauge CB, further evaluation is needed with 11-gauge VAB or surgery. Our data support mammographic follow-up for RS that are benign on 11-gauge VAB. (author)
[en] We present a detailed analysis of the UV spectrum of the calibration star BD+28°4211 using high-quality spectra obtained with the Hubble Space Telescope and Far-Ultraviolet Spectroscopic Explorer satellites. To this aim, we compare quantitatively the observed data with model spectra obtained from state-of-the-art non-LTE metal line-blanketed model atmospheres and synthetic spectra calculated with TLUSTY and SYNSPEC. We thus determine in a self-consistent way the abundances of 11 elements with well-defined lines in the UV, namely those of C, N, O, F, Mg, Si, P, S, Ar, Fe, and Ni. The derived abundances range from about solar to 1/10 solar. We find that the overall quality of the derived spectral fits is very satisfying. Our spectral analysis can be used to constrain rather tightly the effective temperature of BD+28°4211 to a value of Teff = 82, 000 ± 5000 K. We also estimate conservatively that its surface gravity falls in the range log g = 6.2-0.1+0.3. Assuming that the Hipparcos measurement for BD+28°4211 is fully reliable and that our model atmospheres are reasonably realistic, we can reconcile our spectroscopic constraints with the available parallax measurement only if the mass of BD+28°4211 is significantly less than the canonical value of 0.5 M☉ for a representative post-extended horizontal branch star
[en] We present follow-up time-series photometric observations that confirm and extend the results of the significant discovery made by Barlow et al. that the Hot DQ white dwarfs SDSS J220029.08 - 074121.5 and SDSS J234843.30 - 094245.3 are luminosity variable. These are the second and third known members of a new class of pulsating white dwarfs, after the prototype SDSS J142625.71+575218.3. We find that the light curve of SDSS J220029.08 - 074121.5 is dominated by an oscillation at 654.397 ± 0.056 s, and that the light pulse folded on that period is highly nonlinear due to the presence of the first and second harmonic of the main pulsation. We also present evidence for the possible detection of two additional pulsation modes with low amplitudes and periods of 577.576 ± 0.226 s and 254.732 ± 0.048 s in that star. Likewise, we find that the light curve of SDSS J234843.30 - 094245.3 is dominated by a pulsation with a period of 1044.168 ± 0.012 s, but with no sign of harmonic components. A new oscillation, with a low amplitude and a period of 416.919 ± 0.004 s, is also probably detected in that second star. We argue, on the basis of the very different folded pulse shapes, that SDSS J220029.08 - 074121.5 is likely magnetic, while SDSS J234843.30 - 094245.3 is probably not.
[en] As part of a multifaceted effort to better exploit the asteroseismological potential of the pulsating sdB star Feige 48, we present an improved spectroscopic analysis of that star based on new grids of NLTE, fully line-blanketed model atmospheres. To that end, we gathered four high signal-to-noise ratio time-averaged optical spectra of varying spectral resolutions from 1.0 Å to 8.7 Å, and we made use of the results of four independent studies to fix the abundances of the most important metals in the atmosphere of Feige 48. The mean atmospheric parameters we obtained from our four spectra of Feige 48 are: T eff = 29,850 ± 60 K, log g = 5.46 ± 0.01, and log N(He)/N(H) = –2.88 ± 0.02. We also modeled, for the first time, the He II line at 1640 Å from the STIS archive spectrum of the star, and with this line we found an effective temperature and a surface gravity that match well with the values obtained with the optical data. With some fine tuning of the abundances of the metals visible in the optical domain, we were able to achieve a very good agreement between our best available spectrum and our best-fitting synthetic one. Our derived atmospheric parameters for Feige 48 are in rather good agreement with previous estimates based on less sophisticated models. This underlines the relatively small effects of the NLTE approach combined with line blanketing in the atmosphere of this particular star, implying that the current estimates of the atmospheric parameters of Feige 48 are reliable and secure.
[en] We first present our new grids of model atmospheres and spectra for hot subdwarf O (sdO) stars: standard non-LTE (NLTE) H+He models with no metals, NLTE line-blanketed models with C+N+O, and NLTE line-blanketed models with C+N+O+Fe. Using hydrogen and helium lines in the optical range, we make detailed comparisons between theoretical spectra of different grids in order to characterize the line-blanketing effects of metals. We find these effects to be dependent on both the effective temperature and the surface gravity. Moreover, we find that the helium abundance also influences in an important way the effects of line blanketing on the resulting spectra. We further find that the addition of Fe (solar abundance) leads only to incremental effects on the atmospheric structure as compared with the case where the metallicity is defined by C+N+O (solar abundances). We use our grids to perform fits on a 9 A resolution, high signal-to-noise ratio (∼300 blueward of 5000 A) optical spectrum of SDSS J160043.6+074802.9, the only known pulsating sdO star. Our best and most reliable result is based on the fit achieved with NLTE synthetic spectra that include C, N, O, and Fe in solar abundances, leading to the following parameters: Teff = 68,500 ± 1770 K, log g = 6.09 ± 0.07, and log N(He)/N(H) = -0.64 ± 0.05 (formal fitting errors only). This combination of parameters, particularly the comparatively high helium abundance, implies that line-blanketing effects due to metals are not very large in the atmosphere of this sdO star.