3,824 research outputs found

    Correlations and invariance of seismicity under renormalization-group transformations

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    The effect of transformations analogous to those of the real-space renormalization group are analyzed for the temporal occurrence of earthquakes. The distribution of recurrence times turns out to be invariant under such transformations, for which the role of the correlations between the magnitudes and the recurrence times are fundamental. A general form for the distribution is derived imposing only the self-similarity of the process, which also yields a scaling relation between the Gutenberg-Richter b-value, the exponent characterizing the correlations, and the recurrence-time exponent. This approach puts the study of the structure of seismicity in the context of critical phenomena.Comment: Short paper. I'll be grateful to get some feedbac

    L'avis d'ouverture de chantier informatisé: un moyen de prévention et de management

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    L’instruction de sĂ©curitĂ© IS 39 stipule que les travaux exĂ©cutĂ©s par des entreprises sur le domaine du CERN doivent faire l’objet d’un Avis d’Ouverture de Chantier (AOC) rĂ©digĂ© par le superviseur des travaux avant le dĂ©marrage de ceux-ci, dans le but d’attirer l’attention sur les risques et les nuisances qu’ils peuvent engendrer pour les usagers dans la zone de travaux. A cet effet, un groupe de travail a spĂ©cifiĂ© une version informatisĂ©e du document AOC sur EDH afin d’en faciliter la saisie, la visualisation ainsi que la gestion et l’archivage ; Ă  cela s’ajoutent la description des risques et mesures prĂ©ventives possibles, la consultation des diffĂ©rentes bases de donnĂ©es CFU (Contract Follow Up), du patrimoine immobilier et finalement toutes les commoditĂ©s liĂ©es Ă  EDH pour le routage du document selon la liste des rĂŽles des personnes concernĂ©es (approbation, distribution pour information). DĂšs lors, l’AOC devient un moyen d’analyse et de gestion (dĂ©tection et traçabilitĂ© des co-activitĂ©s, des travaux selon les emplacements, firmes intervenantes et dates) grĂące aux diffĂ©rents critĂšres et calculs selon lesquels il est manipulĂ© par les utilisateurs

    Job insecurity and child well-being in single-parent families in Europe: A matter of family and gender policy

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    Objective: The aim of this article is to extend our knowledge about child deprivation in single-parent families from a comparative European perspective. We first analyse the relationship between the employment status of single parents and child deprivation. Furthermore, we examine whether gender equality in the labour market and family cash benefits reduce deprivation and alleviate the consequences of unemployment and employment precariousness. Background: Children from single-parent families suffer deprivation mainly due to their parents' job insecurity and the fact that, in general, there is only one breadwinner in their households, usually a woman. However, the situation of these children may differ between European countries according to gender equality and family policies. Method: We use cross-sectional data from the European Union Statistics on Income and Living Conditions 2014 and multilevel logistic regressions. The analysis is based on a sample of single-parent households (N = 5910) from 28 European countries. Results: The results indicate that temporary employment and unemployment are associated with a greater risk of child deprivation in single-parent families. The results also show that gender equality in the labour market reduces child deprivation, especially in families where the parent has a temporary employment. Redistributive family policies have a more limited impact. Conclusion: The main findings indicate that advances in gender equality in the labour market are essential to combat child deprivation in single-parent families in Europe

    The XMM spectral catalog of SDSS optically selected Seyfert 2 galaxies

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    We present an X-ray spectroscopic study of optically selected (SDSS) Seyfert 2 (Sy2) galaxies. The goal is to study the obscuration of Sy2 galaxies beyond the local universe, using good quality X-ray spectra in combination with high S/N optical spectra for their robust classification. We analyzed all available XMM-Newton archival observations of narrow emission line galaxies that meet the above criteria in the redshift range 0.05<z<0.35. We initially selected narrow line AGN using the SDSS optical spectra and the BPT classification diagram. We further modeled and removed the stellar continuum, and we analyzed the residual emission line spectrum to exclude any possible intermediate-type Seyferts. Our final catalog comprises 31 Sy2 galaxies with median redshift z~0.1. X-ray spectroscopy is performed using the available X-ray spectra from the 3XMM and the XMMFITCAT catalogs. Implementing various indicators of obscuration, we find seven (~23%) Compton-thick AGN. The X-ray spectroscopic Compton-thick classification agrees with other commonly used diagnostics, such as the X-ray to mid-IR luminosity ratio and the X-ray to [OIII] luminosity ratio. Most importantly, we find four (~13%) unobscured Sy2 galaxies, at odds with the simplest unification model. Their accretion rates are significantly lower than the rest of our Sy2 sample, in agreement with previous studies that predict the absence of the broad line region below a certain Eddington ratio threshold.Comment: 12 pages, 6 figures, accepted for publication in A&

    Some Practical Applications of Dark Matter Research

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    Two practical spin-offs from the development of cryogenic dark matter detectors are presented. One in materials research, the other in biology.Comment: 8 pages,4 figure

    Design of asymmetrical directional couplers on ridge and strip SOI technology with high-dimensional variation tolerance

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    [EN] The supermode analysis of asymmetrical directional couplers (ADC) based on SOI technology for strip and ridge structures at 1550 nm is herein reported, targeting to reduce ADC device fabrication requirements. The reported analysis based on supermodes permits us to assess the sensitivity of the ADC coupling efficiency by calculating the index difference between even and odd supermodes. Optimum designs have been found for 100 and 400 nm gaps, respectively, capable of converting and (de) multiplexing both TE0 and TE1 modes taking into account the width, gap, height, and slab thickness variations produced with respect to the nominal design. (C) 2018 Optical Society of AmericaMinisterio de Economia y Competitividad (MINECO) (TEC2015-70858-C2-1-R, RTC-2014-2232-3).GarcĂ­a-RodrĂ­guez, D.; Corral, JL.; Llorente, R. (2018). Design of asymmetrical directional couplers on ridge and strip SOI technology with high-dimensional variation tolerance. Optics Letters. 43(11):2491-2494. https://doi.org/10.1364/OL.43.002491S249124944311Essiambre, R.-J., Kramer, G., Winzer, P. J., Foschini, G. J., & Goebel, B. (2010). Capacity Limits of Optical Fiber Networks. Journal of Lightwave Technology, 28(4), 662-701. doi:10.1109/jlt.2009.2039464Richardson, D. J. (2016). New optical fibres for high-capacity optical communications. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 374(2062), 20140441. doi:10.1098/rsta.2014.0441Mizuno, T., Takara, H., Sano, A., & Miyamoto, Y. (2016). Dense Space-Division Multiplexed Transmission Systems Using Multi-Core and Multi-Mode Fiber. Journal of Lightwave Technology, 34(2), 582-592. doi:10.1109/jlt.2015.2482901Winzer, P. J. (2014). Making spatial multiplexing a reality. Nature Photonics, 8(5), 345-348. doi:10.1038/nphoton.2014.58Melati, D., Alippi, A., Annoni, A., Peserico, N., & Melloni, A. (2017). Integrated all-optical MIMO demultiplexer for mode- and wavelength-division-multiplexed transmission. Optics Letters, 42(2), 342. doi:10.1364/ol.42.000342Garcia-Rodriguez, D., Corral, J. L., & Llorente, R. (2017). Mode Conversion for Mode Division Multiplexing at 850 nm in Standard SMF. IEEE Photonics Technology Letters, 29(11), 929-932. doi:10.1109/lpt.2017.2694605Garcia-Rodriguez, D., Corral, J. L., Griol, A., & Llorente, R. (2017). Dimensional variation tolerant mode converter/multiplexer fabricated in SOI technology for two-mode transmission at 1550  nm. Optics Letters, 42(7), 1221. doi:10.1364/ol.42.001221Le, Y.-S., Wang, Z., Li, Z.-Y., Li, Y., Li, Q., Cui, C., & Wu, C.-Q. (2018). Three-mode all-optical (de)multiplexing on a SOI chip. Optics Communications, 406, 173-176. doi:10.1016/j.optcom.2017.04.059Sun, C., Yu, Y., Ye, M., Chen, G., & Zhang, X. (2016). An ultra-low crosstalk and broadband two-mode (de)multiplexer based on adiabatic couplers. Scientific Reports, 6(1). doi:10.1038/srep38494Hanzawa, N., Saitoh, K., Sakamoto, T., Matsui, T., Tsujikawa, K., Uematsu, T., & Yamamoto, F. (2015). PLC-Based Four-Mode Multi/Demultiplexer With LP11 Mode Rotator on One Chip. Journal of Lightwave Technology, 33(6), 1161-1165. doi:10.1109/jlt.2014.2378281Yamashita, Y., Fujisawa, T., Makino, S., Hanzasa, N., Sakamoto, T., Matsui, T., 
 Saitoh, K. (2017). Design and Fabrication of Broadband PLC-Based Two-Mode Multi/Demultiplexer Using a Wavefront Matching Method. Journal of Lightwave Technology, 35(11), 2252-2258. doi:10.1109/jlt.2016.2641461Zanzi, A., Brimont, A., Griol, A., Sanchis, P., & Marti, J. (2016). Compact and low-loss asymmetrical multimode interference splitter for power monitoring applications. Optics Letters, 41(2), 227. doi:10.1364/ol.41.000227Hanzawa, N., Saitoh, K., Sakamoto, T., Matsui, T., Tsujikawa, K., Koshiba, M., & Yamamoto, F. (2014). Mode multi/demultiplexing with parallel waveguide for mode division multiplexed transmission. Optics Express, 22(24), 29321. doi:10.1364/oe.22.029321Wang, J., He, S., & Dai, D. (2014). On-chip silicon 8-channel hybrid (de)multiplexer enabling simultaneous mode- and polarization-division-multiplexing. Laser & Photonics Reviews, 8(2), L18-L22. doi:10.1002/lpor.201300157Pan, C., & Rahman, B. M. A. (2016). Accurate Analysis of the Mode (de)multiplexer Using Asymmetric Directional Coupler. Journal of Lightwave Technology, 34(9), 2288-2296. doi:10.1109/jlt.2016.2530852Mikkelsen, J. C., Sacher, W. D., & Poon, J. K. S. (2014). Dimensional variation tolerant silicon-on-insulator directional couplers. Optics Express, 22(3), 3145. doi:10.1364/oe.22.003145Xu, K. (2014). Corrections to «On the Design and Optimization of Three-Terminal Light-Emitting Device in Silicon CMOS Technology» [Jul/Aug 14 8201208]. IEEE Journal of Selected Topics in Quantum Electronics, 20(4), 422-422. doi:10.1109/jstqe.2014.2318271Corral, J. L., Garcia-Rodriguez, D., & Llorente, R. (2016). Mode-Selective Couplers for Two-Mode Transmission at 850 nm in Standard SMF. IEEE Photonics Technology Letters, 28(4), 425-428. doi:10.1109/lpt.2015.249708
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