A Monthly Indicator of the French Business Climate

In France, the business tendency surveys conducted in all the important sectors of the economy are key components in diagnosing the economic outlook. Over the years, INSEE has gradually introduced business climate indicators for each business sector. Such indicators summarise the data contained in the many balances of opinion supplied by the surveys and enable to measure the economic situation each month. An indicator of this kind has been lacking, however, for the economy as the whole. To fill this gap and enrich the existing panel of business climate indicators we provide in this paper the first composite indicator based on French business surveys covering all the important economic sectors of the French economy. We chose the dynamic factor analysis to deal with mixed and changing frequencies and time availability of the data. Parameters are estimated by maximum likelihood based on the Kalman filter. Several indicators can be estimated according to the type (sector-based business climate indicators or elementary components) and the number of variables included in the model. To validate our results and choose the best indicator, we defined three criteria : real-time stability, predictive accuracy to forecast GDP growth and ability to reproduce French business cycles. The new monthly synthetic indicator which passed the tests best allows a clear and simple interpretation of all the business surveys and can deliver each month an early and accurate quantitative message concerning the current business climate in France. This indicator can also be used to improve GDP growth forecast.business survey, dynamic factor analysis, unobserved components model, Kalman filter

ISOPHOT Observations of Narrow-Line Seyfert 1 Galaxies

Broad infrared spectra (7-200 micrometer) of four NLS1 galaxies, obtained with the imaging photo-polarimeter (ISOPHOT) on board the Infrared Space Observatory (ISO), are presented. The infrared luminosities and temperatures, opacities and sizes of the emitting dust components are derived. A comparison between the observed infrared spectra and the optical emission line fluxes of a sample of 16 NLS1 galaxies suggests that these objects suffer different degrees of dust absorption according to the inclination of the line of sight with respect to the dust distribution.Comment: Contributed talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

Dust Emission from Active Galactic Nuclei

Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to Seyfert 1 line spectrum for pole-on viewing and Seyfert 2 characteristics in edge-on sources. Although the observed IR is in broad agreement with this scheme, the behavior of the 10 micron silicate feature and the width of the far-IR emission peak remained serious problems in all previous modeling efforts. We show that these problems find a natural explanation if the dust is contained in about 5-10 clouds along radial rays through the torus. The spectral energy distributions (SED) of both type 1 and type 2 sources are properly reproduced from different viewpoints of the same object if the visual optical depth of each cloud is larger than about 60 and the clouds' mean free path increases roughly in proportion to radial distance.Comment: 11 pages, submitted to ApJ Letter

Heterogeneously grown tunable group-IV laser on silicon

Tunable tensile-strained germanium (epsilon-Ge) thin films on GaAs and heterogeneously integrated on silicon (Si) have been demonstrated using graded III-V buffer architectures grown by molecular beam epitaxy (MBE). epsilon-Ge epilayers with tunable strain from 0% to 1.95% on GaAs and 0% to 1.11% on Si were realized utilizing MBE. The detailed structural, morphological, band alignment and optical properties of these highly tensile-strained Ge materials were characterized to establish a pathway for wavelength-tunable laser emission from 1.55 μm to 2.1 μm. High-resolution X-ray analysis confirmed pseudomorphic epsilon-Ge epitaxy in which the amount of strain varied linearly as a function of indium alloy composition in the InxGa1-xAs buffer. Cross-sectional transmission electron microscopic analysis demonstrated a sharp heterointerface between the epsilon-Ge and the InxGa1-xAs layer and confirmed the strain state of the epsilon-Ge epilayer. Lowtemperature micro-photoluminescence measurements confirmed both direct and indirect bandgap radiative recombination between the Γ and L valleys of Ge to the light-hole valence band, with L-lh bandgaps of 0.68 eV and 0.65 eV demonstrated for the 0.82% and 1.11% epsilon-Ge on Si, respectively. The highly epsilon-Ge exhibited a direct bandgap, and wavelength-tunable emission was observed for all samples on both GaAs and Si. Successful heterogeneous integration of tunable epsilon-Ge quantum wells on Si paves the way for the implementation of monolithic heterogeneous devices on Si

Inner Size of a Dust Torus in the Seyfert 1 Galaxy NGC 4151

The most intense monitoring observations yet made were carried out on the Seyfert 1 galaxy NGC 4151 in the optical and near-infrared wave-bands. A lag from the optical light curve to the near-infrared light curve was measured. The lag-time between the V and K light curves at the flux minimum in 2001 was precisely 48+2-3 days, as determined by a cross-correlation analysis. The correlation between the optical luminosity of an active galactic nucleus (AGN) and the lag-time between the UV/optical and the near-infrared light curves is presented for NGC 4151 in combination with previous lag-time measurements of NGC 4151 and other AGNs in the literature. This correlation is interpreted as thermal dust reverberation in an AGN, where the near-infrared emission from an AGN is expected to be the thermal re-radiation from hot dust surrounding the central engine at a radius where the temperature equals to that of the dust sublimation temperature. We find that the inner radius of the dust torus in NGC 4151 is $\sim$ 0.04 pc corresponding to the measured lag-time, well outside the broad line region (BLR) determined by other reverberation studies of the emission lines.Comment: Accepted for publication in ApJ Letters, 13 pages, 3 figures; Corrected typo

Valoración Radiológica del Fracaso de las Prótesis Cervico-Cefálicas de Cadera en Fracturas de Cuello Femoral y Cirugía de Revisión

Lo s autore s analiza n los diferentes signos radiológicos que sugieren intolerancia de la s prótesis cérvico-cefálicas de cader a implantada s po r fractur a cervical que será n sometida s a Cirugí a de Revisión. Se estudian retrospectivamente 61 casos intervenidos entre los años 77 al 89, analizándos e la evolución de los diferentes modelos: Monk, Austin-Moore, Thompson, Mülle r y Robert-Mathys. Asimismo se estudia n la presencia de calcificaciones intr a y periarticulare s y la aparició n de complicaciones. Po r último, se pretende concretar la indicación de la Artroplasti a parcia l de cader a en paciente s anciano s con alto riesgo quirúrgico en oposición a un mejor resultad o de la Artroplasti a Total en el resto de pacientes.The author s analys e the different radiologica l feature s suggestin g intoleranc e o f the cervical-cephali c hi p prosthesis, implante d b y cervica l fractur e a n d submitte d t o revisio n surgery. Retrospectivel y 6 1 cases, whic h wer e carrie d ou t betwee n 197 7 an d 1989, ar e studied, an d the evolutio n o f the different pattern s i n analysed : Monk, Austin-Moore , Thompson , Mülle r an d Robert-Mathys. A t the sam e time , the presenc e o f intr a an d peri-articula r calcification s an d the appearanc e o f complication s ar e examined . Finally , they inten d t o summariz e th e indicatio n o f the hi p hemiarthroplast y i n ol d patien s wit h a hig h surgica l risk oppositio n t o a bette r result o f the tota l hi p arthroplast y in the rest o f th e patients

Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies

The most intense monitoring observations yet made in the optical (UBV) and near-infrared (JHK) wave bands were carried out for nearby Seyfert1 galaxies of NGC 5548, NGC 4051, NGC 3227, and NGC 7469. Over three years of observations with MAGNUM telescope since early 2001, clear time-delayed response of the K-band flux variations to the V-band flux variations was detected for all of these galaxies. Their H-K color temperature was estimated to be 1500-1800 K from the observed flux variation gradients, which supports a view that the bulk of the K flux should originate in the thermal radiation of hot dust that surrounds the central engine. Cross-correlation analysis was performed to quantify the lag time corresponding to the light-travel distance of the hot dust region from the central engine. The measured lag time is 47-53 days for NGC 5548, 11-18 days for NGC 4051, about 20 days for NGC 3227, and 65-87 days for NGC 7469. We found that the lag time is tightly correlated with the optical luminosity as expected from dust reverberation ($\Delta t \propto L^{0.5}$), while only weakly with the central virial mass, which suggests that an inner radius of the dust torus around the active nucleus has a one-to-one correspondence to central luminosity. In the lag time versus central luminosity diagram, the K-band lag times place an upper boundary on the similar lag times of broad-emission lines in the literature. This not only supports the unified scheme of AGNs, but also implies a physical transition from the BLR out to the dust torus that encircles the BLR. Furthermore, our V-band flux variations of NGC 5548 on timescales of up to 10 days are found to correlate with X-ray variations and delay behind them by one or two days, indicating the thermal reprocessing of X-ray emission by the central accretion flow.Comment: ApJ, March 2006, v639 issue, 24 pages, 33 figures, 10 table

Aislamiento y cultivo de células osteoblásticas: Interés para la investigación en cirugía ortopédica y traumatología

Describimos un método de aislamiento y caracterización de células osteoblásticas procedentes de la superficie de trabéculas óseas de explantes obtenidos de metafisis de fémures y tibias de conejo y de cabezas femorales humanas de pacientes sometidos a cirugía protésica de cadera. Después de eliminar las células de la médula ósea de los explantes, estos se despositaron sobre dos tipos de mallas, de 80 y 100 µm., obteniéndose un cultivo en monocarpa que se mostró confluente a partir de los 20 días. La población celular aislada presentó un fenotipo osteoblástico utilizando métodos colorimétricos para determinación de la actividad de fosfatasa alcalina (FA) y morfológicos por medio de la observación con microscopía electrónica de barrido. Las células cultivadas exhibieron una morfología diferente según el grado de confluencia de cultivo, siendo en todo momento positivas las sucesivas determinaciones colorimétricas de FA realizadas a lo largo de la experiencia. Consideramos el método de gran interés en investigación en ortopédica, pues permite el estudio de comportamiento de estas células cuando están sometidas a cualquier tipo de estímulo externo, así como cuando se enfrentan a nuevas generaciones de biomateriales, etc.We describe a method of isolation and characterization of osteoblastic cells taken from the surface of bone trabeculae of explants obtained from femur and tibia metaphysis in rabbits and human femoral head in patients undergoing orthopaedic surgery. Afther removing the cells from the bone marrow of explants, they were placed over two mesh, 80 and 100 µmn, obtaining then a culture in monolayer which showed to be confluent after 20 days. The isolated cell population showed an osteoblastic phenotype using colourmetric methods to determinate the alkaline phosphatase (AF) activity and morphologic methods by means of scanning. The cultivated cell showed a different morphology according to the degree of confluence of the culture, being always positive the sucesive colourmetric determinations of AF along the experiment. We consider the method of a great interest for orthopaedic investigations, since it allows the study of the behaviour of these cells when they are subjet to different types of external stimulus as well as meet they the new generations of biomaterials