1,064 research outputs found

    Ionization states of metallic elements in a quiescent prominence

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    Inthe frame of the Joint Observing Program 133, which was run during the 6th MEDOC Campaign, a quiet prominence was observed on the 1st of November 2000, between17:30-20:00 UT. From the data we obtained, we want to characterize the emission line profiles and to study the different ionization states of many chemical elements present in the cool plasma of the observed prominence. We also intend to analyze the macroscopic velocities of the material and compare the results with theoretical calculations

    Optical determination and identification of organic shells around nanoparticles: application to silver nanoparticles

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    We present a simple method to prove the presence of an organic shell around silver nanoparticles. This method is based on the comparison between optical extinction measurements of isolated nanoparticles and Mie calculations predicting the expected wavelength of the Localized Surface Plasmon Resonance of the nanoparticles with and without the presence of an organic layer. This method was applied to silver nanoparticles which seemed to be well protected from oxidation. Further experimental characterization via Surface Enhanced Raman Spectroscopy (SERS) measurements allowed to identify this protective shell as ethylene glycol. Combining LSPR and SERS measurements could thus give proof of both presence and identification for other plasmonic nanoparticles surrounded by organic shells

    Anxiety, depression, and attachment before and after the first-trimester screening for Down syndrome: comparing couples who undergo ART with those who conceive spontaneously.

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    OBJECTIVES: This study's aim was to describe the emotional status of parents to be before and after the first-trimester combined prenatal screening test. METHODS: One hundred three couples participated, of which 52 had undergone an in vitro fertilization/intracytoplasmic sperm injection treatment [assisted reproductive technology (ART)] and 51 had conceived spontaneously. Participants completed the state scale of the State-trait Anxiety Inventory, the Edinburgh Depression Scale, and the Maternal and Paternal Antenatal Attachment Questionnaire before the first-trimester combined prenatal screening test at around 12 weeks of gestational age (T1) and just after receiving the results at approximately 14 weeks of gestational age (T2). RESULTS: We observed a significant decrease in anxiety and depression symptoms and a significant increase in attachment from T1 to T2. Results showed no differences between groups at either time point, which suggests that ART parents are more similar to than different from parents conceiving spontaneously. Furthermore, given the importance of anxiety during pregnancy, a subsample of women with clinical anxiety was identified. They had significantly higher rates of clinical depression and lower attachment. CONCLUSIONS: These results indicate that, regardless of whether conception was through ART or spontaneous, clinical anxiety in women over the prenatal testing period is associated with more vulnerability during pregnancy (i.e. clinical depression and less attachment to fetus). © 2015 John Wiley & Sons, Ltd

    Oracle-based optimization applied to climate model calibration

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    In this paper, we show how oracle-based optimization can be effectively used for the calibration of an intermediate complexity climate model. In a fully developed example, we estimate the 12 principal parameters of the C-GOLDSTEIN climate model by using an oracle-based optimization tool, Proximal-ACCPM. The oracle is a procedure that finds, for each query point, a value for the goodness-of-fit function and an evaluation of its gradient. The difficulty in the model calibration problem stems from the need to undertake costly calculations for each simulation and also from the fact that the error function used to assess the goodness-of-fit is not convex. The method converges to a ‘best fit' estimate over 10 times faster than a comparable test using the ensemble Kalman filter. The approach is simple to implement and potentially useful in calibrating computationally demanding models based on temporal integration (simulation), for which functional derivative information is not readily availabl

    Picard satellite for solar astrometry

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    The Picard solar satellite has been launched on June 15, 2010. This mission is dedicated to the measurement of the solar diameter with an expected accuracy of milliarcseconds of arc. The radiometer onboard is to measure the total solar irradiance. The final goal is the evaluation of the W, the logarithmic ratio of radius and luminosity. This parameter will help the climatologists to recover past values of the solar luminosity when the radius is available from ancient eclipses data.Comment: 5 pages, 2 figures, Proc. 2nd Galileo-Xu Guangqi Meeting, Ventimiglia - Villa Hanbury, Italy, 11-16 July 201

    Monte-Carlo simulations of the recombination dynamics in porous silicon

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    A simple lattice model describing the recombination dynamics in visible light emitting porous Silicon is presented. In the model, each occupied lattice site represents a Si crystal of nanometer size. The disordered structure of porous Silicon is modeled by modified random percolation networks in two and three dimensions. Both correlated (excitons) and uncorrelated electron-hole pairs have been studied. Radiative and non-radiative processes as well as hopping between nearest neighbor occupied sites are taken into account. By means of extensive Monte-Carlo simulations, we show that the recombination dynamics in porous Silicon is due to a dispersive diffusion of excitons in a disordered arrangement of interconnected Si quantum dots. The simulated luminescence decay for the excitons shows a stretched exponential lineshape while for uncorrelated electron-hole pairs a power law decay is suggested. Our results successfully account for the recombination dynamics recently observed in the experiments. The present model is a prototype for a larger class of models describing diffusion of particles in a complex disordered system.Comment: 33 pages, RevTeX, 19 figures available on request to [email protected]

    Comparison of pelvic floor dysfunction 6 years after uncomplicated vaginal versus elective cesarean deliveries: a cross-sectional study.

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    Clinicians and patients have traditionally believed that elective cesarean section may protect against certain previously ineluctable consequences of labor, including a plethora of urinary, anorectal and sexual dysfunctions. We aimed to evaluate fecal, urinary and sexual symptoms 6 years postpartum, comparing uncomplicated vaginal delivery and elective cesarean delivery, and to assess their impact on quality of life. We conducted a cross-sectional study to compare perineal functional symptomatology between women having singleton elective cesarean deliveries (eCS) and singleton uncomplicated vaginal deliveries (uVD). Women who delivered 6 years before this study were chosen randomly from our hospital database. This database includes demographic, labor, and delivery information, as well as data regarding maternal and neonatal outcomes, all of which is collected at the time of delivery by the obstetrician. Four validated self-administrated questionnaires were sent by post to the participants: the short forms of the Urogenital Distress Inventory, Incontinence Impact Questionnaire, Wexner fecal incontinence scale, and Female Sexual Function Index. Current socio-demographic details, physical characteristics, obstetrical history and mode of delivery at subsequent births were also registered using a self-reported questionnaire. A total of 309 women with uVD and 208 with eCS returned postal questionnaires. The response rate was 49%. Socio-demographic characteristics and fecal incontinence were similar between groups. After eCS, women reported significantly less urgency urinary incontinence (adjusted Relative Risk 0.55; 95% confidence interval 0.34-0.88) and stress incontinence (adjusted Relative Risk 0.53; 95% confidence interval 0.35-0.80) than after uVD. No difference in total Incontinence Impact Questionnaire score was found between both modes of delivery. Lower abdominal or genital pain (adjusted Relative Risk 1.58; 95% confidence interval 1.01-2.49) and pain related to sexual activity (adjusted Relative Risk 2.50; 95% confidence interval 1.19-5.26) were significantly more frequent after eCS than uVD. Six years postpartum, uVD is associated with urinary incontinence, while eCS is associated with sexual and urination pain

    Exemple de gestion d'un site protégé : le plan de zonage du parc national de Port-Cros

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    Décrit le plan de zonage du parc national de Port-Cros, qui a dû prendre en compte : les problèmes fonciers, la production énergétique, l'accueil du public, et l'évolution des peuplements

    SC83288 is a clinical development candidate for the treatment of severe malaria

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    Severe malaria is a life-threatening complication of an infection with the protozoan parasite Plasmodium falciparum, which requires immediate treatment. Safety and efficacy concerns with currently used drugs accentuate the need for new chemotherapeutic options against severe malaria. Here we describe a medicinal chemistry program starting from amicarbalide that led to two compounds with optimized pharmacological and antiparasitic properties. SC81458 and the clinical development candidate, SC83288, are fast-acting compounds that can cure a P. falciparum infection in a humanized NOD/SCID mouse model system. Detailed preclinical pharmacokinetic and toxicological studies reveal no observable drawbacks. Ultra-deep sequencing of resistant parasites identifies the sarco/endoplasmic reticulum Ca(2+) transporting PfATP6 as a putative determinant of resistance to SC81458 and SC83288. Features, such as fast parasite killing, good safety margin, a potentially novel mode of action and a distinct chemotype support the clinical development of SC83288, as an intravenous application for the treatment of severe malaria
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