Context. The contrast of granulation is an important quantity characterizing solar surface convection. Aims. We compare the intensity contrast at 630 nm, observed using the Spectro-Polarimeter (SP) aboard the Hinode satellite, with the 3D radiative MHD simulations of Vögler & Schüssler (2007). Methods. A synthetic image from the simulation is degraded using a theoretical point-spread function o...

Context. Among optical stellar interferometers, the CHARA Array located at Mt Wilson in California offers the potential of very long baselines (up to 330 m) and the prospect of coupling multiple beam combiners. This paper presents the principle and the measured performance of VEGA, Visible spEctroGraph and polArimeter installed in September 2007 at the coherent focus of the array. Aims. With 0....

Bu çalışmada, saf nikel oksit (NiO) ve Evropiyum (Eu) katkılı NiO nanoparçacıklar sol-jel yöntemi kullanılarak sentezlendi. Ni kaynağı olarak Nikel (II) asetat tetrahidrat Eu ise klorür kullanıldı. Sentezleme işlemi 80 ℃’de 3 saat sürede gerçekleştirildi. Sentezlenen 450 1 süreyle tavlandı. Nanoparçacıkları oluşturan bileşikler X-ışını kırınımı (XRD) analiz edildi. Nanoparçacıkların morfolojile...

For sensing systems that characterize the spectro-polarimetric radiance reaching the camera, the origin of the sensed phenomenology is a complex mixture of sources. While some of these sources do not contribute to the polarimetric signature, many do such as the downwelled sky polarization, the target and background pBRDF(polarimetric bi-directional reflectance distribution function), the upwell...

We examine the ability of the Expansionary Fiscal Contraction (EFC) hypothesis to explain the performance of of OECD economies during times of crisis. We ̄nd some limited evidence in its favour: if public consumption is reduced in response to a ̄scal crisis (as de ̄ned by a high level of debt), private consumption does seem to increase. However the size of the e®ect is smaller than that typicall...