Analysis of self-broadened pure rotational and rovibrational lines of methyl chloride at room temperature

International audienceRovibrational absorption spectra of methyl chloride in the spectral region between 2800 and 3200 cm 1 were recorded with a high-resolution Fourier spectrometer. A multispectrum fitting procedure was used to analyze 527 transitions of the ν1 band and to retrieve the self-broadening coefficients for various J- and K-values with an estimated accuracy around 8%. Pure rotational transitions of CH3Cl in the submillimeter/terahertz region (0.2-1.4 THz) were also investigated using two complementary techniques of frequency-multiplication and continuous-wave photomixing. 43 pure rotational self-broadening coefficients were extracted with the accuracy between 3 and 5%. The whole set of measured values was used to model the J- and K-rotational dependences of the self-broadening coefficients by second-order polynomials. In addition, semi-classical calculations were performed, based on the real symmetric-top geometry of the active molecule, an intermolecular potential model including not only the dominant electrostatic but also the short-range forces, as well as on an exact classical treatment of the relative translational motion of the colliding partners. Comparison of all experimental and theoretical results shows similar rotational dependences and no significant vibrational dependence, so that extrapolations to other spectral regions should be straightforward

Long-distance frequency dissemination with a resolution of 10-17

We use a new technique to disseminate microwave reference signals along ordinary optical fiber. The fractional frequency resolution of a link of 86 km in length is 10-17 for a one day integration time, a resolution higher than the stability of the best microwave or optical clocks. We use the link to compare the microwave reference and a CO2/OsO4 frequency standard that stabilizes a femtosecond laser frequency comb. This demonstrates a resolution of 3.10-14 at 1 s. An upper value of the instability introduced by the femtosecond laser-based synthesizer is estimated as 1.10-14 at 1 s

Multicenter randomized phase II study of two schedules of docetaxel, estramustine, and prednisone versus mitoxantrone plus prednisone in patients with metastatic hormone-refractory prostate cancer

A B S T R A C T Purpose Mitoxantrone-corticosteroid is currently the standard palliative treatment in hormone-refractory prostate cancer (HRPC) patients. Recent clinical trials documented the high activity of the docetaxel-estramustine combination. We conducted a randomized phase II study to evaluate prostate-specific antigen (PSA) response (primary end point) and safety of two docetaxelestramustine-prednisone (DEP) regimens and mitoxantrone-prednisone (MP). Patients and Methods One hundred thirty metastatic HRPC patients were randomly assigned to receive docetaxel (70 mg/m 2 on day 2 or 35 mg/m 2 on days 2 and 9 of each 21-day cycle) and estramustine (280 mg PO tid on days 1 through 5 and 8 through 12) or mitoxantrone 12 mg/m 2 every 3 weeks; all patients received prednisone (10 mg daily). Results One hundred twenty-seven patients were assessable for PSA response and safety. A Ն 50% PSA decline was found in a greater percentage of patients in the docetaxel arms (67% and 63%) compared with MP (18%; P ϭ .0001). Median time to PSA progression was five times longer with DEP than with MP (8.8 and 9.3 v 1.7 months, respectively; P ϭ .000001). Overall survival was better in the docetaxel arms (18.6 and 18.4 months) compared with the MP arm (13.4 months), but not significantly so (P ϭ .3). Crossover rates differed significantly among treatment arms (16%, 10%, and 48% in arms A, B, and C, respectively; P ϭ .00001). Treatment-related toxicities were mild and mainly hematologic. Conclusion The results of this randomized phase II study showed significantly higher PSA decline Յ 50% and longer times to progression in HRPC patients receiving DEP-based chemotherapy than MP, and that DEP could be proposed in this setting

An experimental test for the mass independent isotopic fractionation mechanism proposed for ozone

International audienceOzone exhibits large and mass independent isotopic fractionations (MIF) in oxygen isotope ratios relative to molecular di-oxygen (O2) from which it is formed. An interpretation of this effect was proposed based on the behavior of the indistinguishable isotopes 16O in scattering processes. We report here an experiment aimed at testing one of the predictions of this model.O3 was formed by high frequency discharge in O2 with pressures ranging between 1.6 and 38 Torr. The isotopic evolution of the closed O2 reservoir was monitored during its distillation taking place during the continuous removal of ozone by condensation. Its composition evolves from a mass independent to a mass dependent fractionation along with the decrease in pressure. The isotopic pathways defined by this evolution in the 3 isotopes diagram are in quantitative agreement with the theoretical prediction of the disappearance of MIF with the increase of the complex lifetime stabilized as ozone

Source level estimation of two blue whale subspecies in southwestern Indian Ocean

International audienceBlue whales produce intense, stereotypic low frequency calls that are particularly well suited for transmission over long distances. Because these calls vary geographically, they can be used to gain insight into subspecies distribution. In the Southwestern Indian Ocean, acoustic data from a triad of calibrated hydrophones maintained by the International Monitoring System provided data on blue whale calls from two subspecies: Antarctic and pygmy blue whales. Using time difference of arrival and least-squares hyperbolic methods, the range and location of calling whales were determined. By using received level of calls and propagation modeling, call source levels of both subspecies were estimated. The average call source level was estimated to 179 +/- 5 dB re 1 mu Pa-rms at 1 m over the 17-30 Hz band for Antarctic blue whale and 174 +/- 1 dB re 1 mu Pa-rms at 1 m over the 17-50 Hz band for pygmy blue whale. According to previous estimates, slight variations in the source level could be due to inter-individual differences, inter-subspecies variations and the calculation method. These are the first reported source level estimations for blue whales in the Indian Ocean. Such data are critical to estimate detection ranges of calling blue whales. (C) 2010 Acoustical Society of Americ