Amélioration des performances du RAKE par pré-filtrage adaptatif autodidacte pour la liaison descendante de l'UMTS-FDD

é- Cet article présente un récepteur linéaire utilisant un égaliseur à réponse impulsionnelle infinie au niveau chip pour la liaison descendante de l'UMTS-FDD. Nous montrons que ce récepteur peut être réalisé en utilisant le principe du retournement temporel, des filtres récursifs adaptatifs autodidactes et un récepteur RAKE. Le récepteur ainsi constitué présente des performances supérieures à celles du récepteur RAKE pour un accroissement de complexité faible

The ARC-EN-CIEL radiation sources

MOPC005International audienceThe ARC-EN-CIEL (Accelerator-Radiation for Enhanced Coherent Intense Extended Light) project proposes a panoply of light sources for the scientific community on a 1 GeV superconducting LINAC (phase 2) on which two ERL loops (1 and 2 GeV) are added in phase 3. LEL1 (200-1.5 nm), LEL2 (10-0.5 nm) and LEL4 (2-0.2 nm) are three kHz High Gain Harmonic Generation Free Electron Laser sources seeded with the High order Harmonics generated in Gas, with 100-30 FWHM pulses. A collaboration, which has been set-up with the SCSS Prototype Accelerator in Japan to test this key concept of ARC-EN-CIEL, has led to the experimental demonstration of the seeding with HHG and the observation up the 7th non linear harmonic with a seed at 160 nm. LEL3 (40-8 nm) installed on the 1 GeV loop is a MHz FEL oscillator providing higher average power and brilliance. In addition, in vacuum undulator spontaneous emission source extend the spectral range above 10 keV and intense THz radiation is generated by edge radiation of bending magnets. Optimisations and light sources characteristics are described

Fast Measurements of the Electron Beam Transverse Size and Position on SOLEIL Storage Ring

On SOLEIL storage ring, three beamlines are dedicated to electron beam diagnostics: two in the X-ray range and one in the visible range. The visible range beamline uses the synchrotron radiation which is emitted in one of the ring dipoles and further extracted by a slotted mirror operated in surf-mode (surfing on the upper part of the synchrotron layer). The radiation in the visible range is then transported towards a diagnostic hutch in the experimental hall, allowing electron beam imaging at the source point onto a standard CCD camera. In the perspective of prototyping works for the eventually forthcoming upgrade of SOLEIL, and for the on-going commissioning of a new Multipole Injection Kicker (MIK), we recently installed in this hutch two new branches ended by two new cameras (a KALYPSO system and a standard CMOS camera). We report in this paper the optimization we performed on the mirror mode of operation, as well as on spectral filtering, polarization selection, image plane location, fast acquisition tools, to improve the resolution and increase the speed of our initial transverse beam size measurement at source point

The future of mammary stem cell biology: the power of in vivo transplants

The recent review by Smith and Medina [1] of in vivo transplantation models and their role in investigating mammary stem cell (MaSC) biology provides comprehensive coverage of the history and complexity of the ‘gold standard ’ MaSC assay in mice. This includes a description of the pioneering studies that showed that mammary epithelial outgrowths can be generated in cleared mammary fat pads transplanted with explants or admixtures of mammary cells [2]. However, this approach clearly does not lend itself to prospective analysis of isolated subpopulations in order to identify which cells possess in vivo regenerative activity. More recently, success in obtaining complex mammary gland structures from transplanted suspensions of single cells has now made this possible [3-7]. Moreover, the regenerated structures have been shown to contain daughter cells with the same in viv

Multi-wavelength Bragg coherent X-ray diffraction imaging of Au particles

International audienceMulti-wavelength (mw) Bragg coherent X-ray diffraction imaging (BCDI) is demonstrated on a single Au particle. The multi-wavelength Bragg diffraction patterns are inverted using conventional phase-retrieval algorithms where the dilation of the effective pixel size of a pixelated 2D detector caused by the variation of the X-ray beam energy is mitigated by interpolating the raw data. The reconstructed Bragg electron density and phase field are in excellent agreement with the results obtained from conventional rocking scans of the same particle. Voxel sizes of about 6 3 nm 3 are obtained for reconstructions from both approaches. Phase shifts as small as 0.41 rad, which correspond to displacements of 14 pm and translate into strain resolution better than 10 À4 in the Au particle, are resolved. The displacement field changes shape during the experiment, which is well reproduced by finite element method simulations considering an inhomogeneous strained carbon layer deposited on the Au particle over the course of the measurements. These experiments thus demonstrate the very high sensitivity of BCDI and mw-BCDI to strain induced by contaminations. Furthermore, mw-BCDI offers new opportunities for in situ and operando 3D strain imaging in complex sample environments

Contraception determinants in youths of Sierra Leone are largely behavioral

Background: Sexual initiation occurs early in Sierra Leone. This study aims to analyze the determinants of condom and/or contraceptive use among a representative sample of young persons (10 to 24 years) in Sierra Leone. Methods: This is a secondary analysis of data from a study conducted to monitor the implementation of a UNFPA package of interventions directed to improve SRH in young people of Sierra Leone. This assessment was conducted in 2016 at the end of the Ebola outbreak. In consequence, determinants linked to healthy lifestyle behaviors and UNFPA interventions were explored in addition to the usual determinants: socio demographic and sexual lifestyle. This study is a household quantitative survey with open ended questions used to illustrate and complete the analysis. Results: A total of 1409 young people were interviewed: of these, 216 boys and 381 girls were sexually active. Those who were pregnant or wished for pregnancy were excluded, leaving 194 boys and 268 girls for the analysis of determinants. The proportion of young people using neither condom nor other contraception at their last sexual intercourse in the whole sample was 40.5% and there was no statistically significant difference between boys and girls (42.3 vs 39.2; P = 0.504). Determinants were assessed and, after multivariable analysis, results differed between boys and girls and showed the importance of behavioral aspects. Four determinants were common to boys and girls: literacy, distance, negotiation capacity and hand washing. However, the distance factor for girls was to the health facility and for boys it was to school. Three more determinants remained in the boy's model: sleeping under a bednet, number of sexual partners and knowledge of contraceptive methods. Opinions about condoms and contraception revealed important barriers; opposition to contraceptive use was the main reason for non-use for both boys and girls, while lack of access was an important reason for boys. Conclusion: There is a need to reach out to the 40% of young people who are sexually active and neither pregnant nor with pregnancy desire, and are not using condom or contraception

Ovarian steroid hormones: what's hot in the stem cell pool?

The vital role of ovarian hormones in the development of the normal breast foreshadowed their importance in mammary stem cell regulation. Two recent papers reveal that 17β-estradiol and progesterone control the size and repopulating ability of the mammary stem cell compartment. This likely occurs via paracrine signaling from steroid receptor-positive luminal cells to steroid receptor-negative stem cells. These findings illuminate roles for the female sex steroids in mobilizing the stem cell pool in the normal breast, and also provide a crucial link between the known hormonal risks of breast cancer and the potential stem cell origin of this disease

The FEL SASE operation, bunch compression and the beam heater

We discuss the conditions required for an optimal SASE FEL operation when bunch compression techniques are exploited to enhance the bunch peak current. We discuss the case of velocity bunching and magnetic bunch compression. With the reference to the latter technique we provide a quantitative estimate of the amount of laser heater power necessary to suppress the micro-bunching instability without creating any problem to the SASE dynamic