Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release

Optical and X-ray studies of interacting binaries

Available from British Library Document Supply Centre-DSC:D213797 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Spectral distribution of Be/X-ray binaries in the small magellanic cloud

The spectral distributions of Be/X-ray binaries in the Large Magellanic Cloud and Galaxy have been shown to differ significantly from the distribution of isolated Be stars in the Galaxy. Population synthesis models can explain this difference in spectral distributions through substantial angular momentum loss from the binary system. In this work, we explore the spectral distribution of Be/X-ray binaries in the Small Magellanic Cloud (SMC) using high signal-to-noise ratio spectroscopy of a sample of 37 optical counterparts to known X-ray pulsars. Our results show that the spectral distribution of Be/X-ray binaries in the SMC is consistent with that of the Galaxy, despite the lower metallicity environment of the SMC. This may indicate that, although the metallicity of the SMC is conducive to the formation of a large number of high-mass X-ray binaries, the spectral distribution of these systems is likely to be most strongly influenced by angular momentum losses during binary evolution, which are not particularly dependent on the local metallicity<br/

Intragastric acidification reduces the occurrence of false-negative urea breath test results in patients taking a proton pump inhibitor

The aim of this study was to investigate whether reducing intragastric pH, at the time of urea ingestion, decreases the likelihood of false-negative (FN) urea breath test (UBT) results in patients taking a proton pump inhibitor (PPI). Methods : Patients with active Helicobacter pylori infection underwent a baseline 14 C-UBT (UBT-1) followed by treatment with lansoprazole 30 mg/day for 14 to 16 days. On day 13, patients returned for a repeat standard UBT (UBT-2). Between days 14 to 16, patients underwent a modified UBT (UBT-3), which included consuming 200 ml of 0.1 N citrate solution 30 min before and at the time of 14 C-urea administration. Breath samples were collected 10 and 15 min after 14 C-urea ingestion. Mean 14 CO 2 excretion and the number of FN and equivocal UBT results were compared for the three UBTs. Results : A total of 20 patients completed the study. Lansoprazole caused a significant decrease in mean breath 14 CO 2 excretion (disintegrations per minute) between UBT-1 (2.96 ± 0.23) and UBT-2 (2.08 ± 0.52, p < 0.05 ). Lansoprazole caused six (30%) FN and eight (40%) equivocal UBT-2 results. Mean breath 14 CO 2 excretion for UBT-3 (677 ± 514) was greater than for UBT-2 (234 ± 327, p = 0.001 ). UBT-3 caused only two (10%) FN and three (15%) equivocal results. The 15-min breath sample caused fewer FN and equivocal results than the 10-min sample for both UBT-2 and UBT-3. Conclusions : Giving citrate before and at the time of 14 C-urea administration increases mean breath 14 CO 2 excretion and decreases FN and equivocal UBT results in patients taking a PPI. These observations suggest that it may be possible to design a UBT protocol that will remain accurate in the face of PPI therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71971/1/j.1572-0241.2001.03687.x.pd