Millimetric Astronomy from the High Antarctic Plateau: site testing at Dome C

Preliminary site testing at Dome C (Antarctica) is presented, using both Automatic Weather Station (AWS) meteorological data (1986-1993) and Precipitable Water Vapor (PWV) measurements made by the authors. A comparison with South Pole and other sites is made. The South Pole is a well established astrophysical observing site, where extremely good conditions are reported for a large fraction of time during the year. Dome C, where Italy and France are building a new scientific station, is a potential observing site in the millimetric and sub-millimetric range. AWS are operating at both sites and they have been continuously monitoring temperature, pressure, wind speed and direction for more than ten years. Site testing instruments are already operating at the South Pole (AASTO, Automated Astrophysical Site-Testing Observatory), while ''light'' experiments have been running at Dome C (APACHE, Antarctic Plateau Anisotropy CHasing Experiment) during summertime. A direct comparison between the two sites is planned in the near future, using the AASTO. The present analysis shows that the average wind speed is lower at Dome C (~1 m/s) than at the South Pole (~2 m/s), while temperature and PWV are comparable.Comment: 10 pages, 8 figures, se also http://www.atnf.csiro.au/pasa/16_2

The Sunyaev-Zeldovich Effect at 1 and 2 mm towards ROSAT Clusters

An observing campaign was devoted to the search for the Sunyaev-Zeldovich (S-Z) effect towards X-ray ROSAT Clusters in the millimetric spectral domain. A double channel (1.2 and 2 {\it mm}) photometer was installed at the focus of the 15m Swedish ESO Submillimeter Telescope (SEST) in Chile in september 1994 and 1995 and observations of the targets S1077, A2744, S295 and RXJ0658-5557 were gathered. Detections were found for A2744 at 1 {\it mm} and in both channels (at 1.2 and 2 {\it mm}) towards RXJ0658-5557. For the first time there is evidence for the S-Z enhancement and both the latter and the decrement were detected on the same source. We discuss astrophysical and systematic effects which could give origin to these signals.Comment: 6 pg Latex file (style file included) including 1 ps figure, XVIth Moriond Astrophysics Meeting "The Anisotropies of the Cosmic Microwave Background", Les Arcs, Savoie-France, March 16-23 199

COMPASS: a 2.6m telescope for CMBR polarization studies

COMPASS (COsmic Microwave Polarization at Small Scale) is an experiment devoted to measuring the polarization of the CMBR. Its design and characteristics are presented

Treatment of esophageal achalasia in children: Today and tomorrow

Esophageal achalasia (EA) is a rare esophageal motility disorder in children. Laparoscopic Heller myotomy (LHM) represents the treatment of choice in young patients. Peroral endoscopic myotomy (POEM) is becoming an alternative to LHM. The aim of this study is to evaluate the effectiveness, safety, and outcomes of POEM vs LHM in treatment of children with EA. Data of pediatric patients with EA, who underwent LHM and POEM from February 2009 to December 2013 in two centers, were collected. Eighteen patients (9 male, mean age: 11.6 years; range: 2-17 years) were included. Nine patients (6 male, mean age: 10.7 years; range: 2-16 years) underwent LHM, and the other 9 (3 males, mean age: 12.2 years; range: 6-17 years) underwent POEM procedure. Mean operation time was shorter in POEM group compared with LHM group (62/149 minutes). Myotomy was longer in POEM group than in LHM group (11/7 cm). One major complication occurred after LHM (esophageal perforation). No clinical and manometric differences were observed between LHM and POEM in follow-up. The incidence of iatrogenic gastroesophageal reflux disease was low (1 patient in both groups). Results of a midterm follow-up show that LHM and POEM are safe and effective treatments also in children. Besides, POEM is a mini-invasive technique with an inferior execution timing compared to LHM. A skilled endoscopic team is mandatory to perform this procedur

Looking for the S-Z Effect towards Distant ROSAT Clusters of Galaxies

We report on observations of the Sunyaev-Zeldovich effect towards X-ray ROSAT clusters taken with a double channel (1.2 and 2 mm) photometer installed at the focus of the 15m SEST antenna in Chile. This paper describes the first results obtained for the high-z clusters S1077, A2744 and S295. Marginal detections were found for A2744 and at 1 mm for S1077. We discuss these data in terms of contamination of sources along the line of sight and give a constraint on the amplitude of the kinematic effect.Comment: 17 pg Latex file (using aasms4.sty) gzip'd tar'd uuencoded file including 1 ps figure, ApJ Letter in pres

CBR anisotropy and cold dust observations from Antarctica

Ground-based experiments in Antarctica exploring cosmic background-radiation (CBR) anisotropies at intermediate angular scales and millimeter wavelengths are discussed. The spectra of the Magellanic Clouds is analyzed, and the determination of sky fluctuations is addressed. Focus is placed on the detection of thermal emission from a very cold component of the interstellar material both in the galaxy and Magellanic Clouds. Estimated total dust column densities are found to be an order of magnitude greater than those previously found, while statistical sky fluctuations are estimated at a level of less than 0.0002

The Case for Thoughtful Prescribing of Proton Pump Inhibitors in Infants.

International audienc

The enhancement and decrement of the Sunyaev-Zel'dovich effect towards the ROSAT Cluster RXJ0658-5557The enhancement and decrement of the Sunyaev-Zeldovich effect towards the ROSAT Cluster RXJ0658-5557

Published in: Astrophys. J. 513 (1999) 23 citations recorded in [Science Citation Index] Abstract: We report simultaneous observations at 1.2 and 2 mm, with a double channel photometer on the SEST Telescope, of the X-ray cluster RXJ0658-5557 in search for the Sunyaev-Zel'dovich (S-Z). The S-Z data were analyzed using the relativistically correct expression for the Comptonization parameter and we find from the detected decrement (2.60 +/- 0.79) ~ 10^{-4}, which is consistent with that computed using the X-ray (ROSAT and ASCA) observations. The uncertainty includes contributions due to statistical uncertainty in the detection and systematics and calibration. The 1.2 {mm} channel data alone gives rise to a larger Comptonization parameter and this result is discussed in terms of contamination from foreground sources and/or dust in the cluster or from a possible systematic effect. We then make use of the combined analysis of the ROSAT and ASCA X-ray satellite observations to determine an isothermal model for the S-Z surface brightness. Since the cluster is asymmetrical and probably in a merging process, models are only approximate. The associated uncertainty can, however, be estimated by exploring a set of alternative models. We then find as the global uncertainty on the Comptonization parameter a factor of 1.3. Combining the S-Z and the X-ray measurements, we determine a value for the Hubble constant. The 2 mm data are consistent with H_0(q_0 = 1/2)= 53^{+38}_{-28} km/s Mpc^{-1}, where the uncertainty is dominated by the uncertainty in models of the X-ray plasma halo