The brightest OH maser in the sky: a flare of emission in W75 N

A flare of maser radio emission in the OH-line 1665 MHz has been discovered in the star forming region W75 N in 2003, with the flux density of about 1000 Jy. At the time it was the strongest OH maser detected during the whole history of observations since the discovery of cosmic masers in 1965. The flare emission is linearly polarized with a degree of polarization near 100%. A weaker flare with a flux of 145 Jy was observed in this source in 2000 - 2001, which was probably a precursor of the powerful flare. Intensity of two other spectral features has decreased after beginning of the flare. Such variation of the intensity of maser condensation emission (increasing of one and decreasing of the other) can be explained by passing of the magneto hydrodynamic shock across regions of enhanced gas concentration.Comment: 9 pages with 2 figures, accepted for publication in Astronomy Letter

Clustered Star Formation in W75 N

We present 2" to 7" resolution 3 mm continuum and CO(J=1-0) line emission and near infrared Ks, H2, and [FeII] images toward the massive star forming region W75 N. The CO emission uncovers a complex morphology of multiple, overlapping outflows. A total flow mass of greater than 255 Msun extends 3 pc from end-to-end and is being driven by at least four late to early-B protostars. More than 10% of the molecular cloud has been accelerated to high velocities by the molecular flows (> 5.2 km/s relative to v{LSR}) and the mechanical energy in the outflowing gas is roughly half the gravitational binding energy of the cloud. The W75 N cluster members represent a range of evolutionary stages, from stars with no apparent circumstellar material to deeply embedded protostars that are actively powering massive outflows. Nine cores of millimeter-wavelength emission highlight the locations of embedded protostars in W75 N. The total mass of gas & dust associated with the millimeter cores ranges from 340 Msun to 11 Msun. The infrared reflection nebula and shocked H2 emission have multiple peaks and extensions which, again, suggests the presence of several outflows. Diffuse H2 emission extends about 0.6 parsecs beyond the outer boundaries of the CO emission while the [FeII] emission is only detected close to the protostars. The infrared line emission morphology suggests that only slow, non-dissociative J-type shocks exist throughout the pc-scale outflows. Fast, dissociative shocks, common in jet-driven low-mass outflows, are absent in W75 N. Thus, the energetics of the outflows from the late to early B protostars in W75 N differ from their low-mass counterparts -- they do not appear to be simply scaled-up versions of low-mass outflows.Comment: Astrophysical Journal, in press. 23 pages plus 10 figures (jpg format). See http://www.aoc.nrao.edu/~dshepher/science.shtml for reprint with full resolution figure

Non-adaptive Measurement-based Quantum Computation and Multi-party Bell Inequalities

Quantum correlations exhibit behaviour that cannot be resolved with a local hidden variable picture of the world. In quantum information, they are also used as resources for information processing tasks, such as Measurement-based Quantum Computation (MQC). In MQC, universal quantum computation can be achieved via adaptive measurements on a suitable entangled resource state. In this paper, we look at a version of MQC in which we remove the adaptivity of measurements and aim to understand what computational abilities still remain in the resource. We show that there are explicit connections between this model of computation and the question of non-classicality in quantum correlations. We demonstrate this by focussing on deterministic computation of Boolean functions, in which natural generalisations of the Greenberger-Horne-Zeilinger (GHZ) paradox emerge; we then explore probabilistic computation, via which multipartite Bell Inequalities can be defined. We use this correspondence to define families of multi-party Bell inequalities, which we show to have a number of interesting contrasting properties.Comment: 13 pages, 4 figures, final version accepted for publicatio

Averaging lifetimes for B hadron species

The measurement of the lifetimes of the individual B species are of great interest. Many of these measurements are well below the 10 $\%$ level of precision. However, in order to reach the precision necessary to test the current theoretical predictions, the results from different experiments need to be averaged. Therefore, the relevant systematic uncertainties of each measurement need to be well defined in order to understand the correlations between the results from different experiments. \par In this paper we discuss the dominant sources of systematic errors which lead to correlations between the different measurements. We point out problems connected with the conventional approach of combining lifetime data and discuss methods which overcome these problems

CLASS B1152+199 and B1359+154: Two New Gravitational Lens Systems Discovered in the Cosmic Lens All-Sky Survey

The third phase of the Cosmic Lens All-Sky Survey (CLASS) has recently been completed, bringing the total number of sources imaged to over 15000 in the CLASS and JVAS combined survey. In the VLA observations carried out in March and April of 1998, two new candidate lensed systems were discovered: CLASS B1152+199 and B1359+154. B1152+199 is a 1.6 arcsecond double, with a background quasar at z=1.019 lensed by a foreground galaxy at z=0.439. The relatively flat radio spectra of the lensed images, combined with a previous ROSAT detection of the source, make B1152+199 a strong candidate for time delay studies at both radio and X-ray wavelengths. B1359+154 is a quadruply lensed quasar at z=3.235, with a maximum image separation of 1.7 arcseconds. As yet, the redshift of the lensing object in this system is undetermined. The steep spectral index of the source suggests that B1359+154 will not exhibit strong variability, and is therefore unlikely to be useful for determining the Hubble constant from measured time delays.Comment: accepted for publication in The Astronomical Journa

A disk of dust and molecular gas around a high-mass protostar

The processes leading to the birth of low-mass stars such as our Sun have been well studied, but the formation of high-mass (> 8 x Sun's mass) stars has heretofore remained poorly understood. Recent observational studies suggest that high-mass stars may form in essentially the same way as low-mass stars, namely via an accretion process, instead of via merging of several low-mass (< 8 Msun) stars. However, there is as yet no conclusive evidence. Here, we report the discovery of a flattened disk-like structure observed at submillimeter wavelengths, centered on a massive 15 Msun protostar in the Cepheus-A region. The disk, with a radius of about 330 astronomical units (AU) and a mass of 1 to 8 Msun, is detected in dust continuum as well as in molecular line emission. Its perpendicular orientation to, and spatial coincidence with the central embedded powerful bipolar radio jet, provides the best evidence yet that massive stars form via disk accretion in direct analogy to the formation of low-mass stars

The Role of Thailand in the International Trade in CITES-Listed Live Reptiles and Amphibians

BACKGROUND: International wildlife trade is one of the leading threats to biodiversity conservation. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is the most important initiative to monitor and regulate the international trade of wildlife but its credibility is dependent on the quality of the trade data. We report on the performance of CITES reporting by focussing on the commercial trade in non-native reptiles and amphibians into Thailand as to illustrate trends, species composition and numbers of wild-caught vs. captive-bred specimens. METHODOLOGY/PRINCIPAL FINDINGS: Based on data in the WCMC-CITES trade database, we establish that a total of 75,594 individuals of 169 species of reptiles and amphibians (including 27 globally threatened species) were imported into Thailand in 1990-2007. The majority of individuals (59,895, 79%) were listed as captive-bred and a smaller number (15,699, 21%) as wild-caught. In the 1990s small numbers of individuals of a few species were imported into Thailand, but in 2003 both volumes and species diversity increased rapidly. The proportion of captive-bred animals differed greatly between years (from 0 to >80%). Wild-caught individuals were mainly sourced from African countries, and captive-bred individuals from Asian countries (including from non-CITES Parties). There were significant discrepancies between exports and imports. Thailand reports the import of >10,000 individuals (51 species) originating from Kazakhstan, but Kazakhstan reports no exports of these species. Similar discrepancies, involving smaller numbers (>100 individuals of 9 species), can be seen in the import of reptiles into Thailand via Macao. CONCLUSION/SIGNIFICANCE: While there has been an increase in imports of amphibian and reptiles into Thailand, erratic patterns in proportions of captive-bred specimens and volumes suggests either capricious markets or errors in reporting. Large discrepancies with respect to origin point to misreporting or possible violations of the rules and intentions of CITES

Use of near infrared reflectance spectroscopy to predict nitrogen uptake by winter wheat within fields with high variability in organic matter

In this study, the ability to predict N-uptake in winter wheat crops using NIR-spectroscopy on soil samples was evaluated. Soil samples were taken in unfertilized plots in one winter wheat field during three years (1997-1999) and in another winter wheat field nearby in one year (2000). Soil samples were analyzed for organic C content and their NIR-spectra. N-uptake was measured as total N-content in aboveground plant materials at harvest. Models calibrated to predict N-uptake were internally cross validated and validated across years and across fields. Cross-validated calibrations predicted N-uptake with an average error of 12.1 to 15.4 kg N ha-1. The standard deviation divided by this error (RPD) ranged between 1.9 and 2.5. In comparison, the corresponding calibrations based on organic C alone had an error from 11.7 to 28.2 kg N ha-1 and RPDs from 1.3 to 2.5. In three of four annual calibrations within a field, the NIR-based calibrations worked better than the organic C based calibrations. The prediction of N-uptake across years, but within a field, worked slightly better with an organic C based calibration than with a NIR based one, RPD = 1.9 and 1.7 respectively. Across fields, the corresponding difference was large in favour of the NIR-calibration, RPD = 2.5 for the NIR-calibration and 1.5 for the organic C calibration. It was concluded that NIR-spectroscopy integrates information about organic C with other relevant soil components and therefore has a good potential to predict complex functions of soils such as N-mineralization. A relatively good agreement of spectral relationships to parameters related to the N-mineralization of datasets across the world suggests that more general models can be calibrated