We present 850um imaging of the XMM-LSS field observed for 170 hours as part of the James Clerk Maxwell Telescope SCUBA-2 Large eXtragalactic Survey (S2LXS). S2LXS XMM-LSS maps an area of 9 square ...degrees, reaching a moderate depth of 1-sigma ~ 4 mJy/beam. This is the largest contiguous area of extragalactic sky mapped by JCMT at 850um to date. The wide area of the S2LXS XMM-LSS survey allows us to probe the ultra-bright (S_850um > 15 mJy), yet rare submillimetre population. We present the S2LXS XMM-LSS catalogue, which comprises 40 sources detected at >5-sigma significance, with deboosted flux densities in the range of 7 mJy to 48 mJy. We robustly measure the bright-end of the 850um number counts at flux densities >7 mJy, reducing the Poisson errors compared to existing measurements. The S2LXS XMM-LSS observed number counts show the characteristic upturn at bright fluxes, expected to be motivated by local sources of submillimetre emission and high-redshift strongly lensed galaxies. We find that the observed 850um number counts are best reproduced by model predictions that include either strong lensing or source blending from a 15 arcsec beam, indicating that both may make an important contribution to the observed over-abundance of bright single dish 850um selected sources. We make the S2LXS XMM-LSS 850um map and >5-sigma catalogue presented here publicly available.
Evolution of microstructure and texture of commercial purity (CP) titanium grade 2 during two-step deformation process was investigated in this work. Deformation technique utilized in first step of ...samples preparation was the KoBo type extrusion. In the second step, further deformation was performed by the cold rolling process in order to facilitate high level of grain refinement.
After the first step of deformation microstructure of titanium sample consists of equiaxed grains with no internal structure, but with distinct distribution of grain sizes. Texture of KoBo extruded Ti sample is typical with 0001 basal planes oriented parallel to the extrusion direction. During the cold rolling microstructure is significantly refined. Some grains are elongated in the rolling direction, however most of the microstructure is occupied by fine grains with close to equiaxed shape. Almost 50% of the microstructure consists of highly refined fraction of grains with diameter below one micrometer. Analysis of microstructure suggest that refined grains are produced due to dynamic recrystallization that occurs both during KoBo and during subsequent cold rolling in the fine grained areas of KoBo extruded sample.
•Deformed microstructure of titanium after KoBo and CR is investigated.•Deformation during KoBo extrusion and CR is dominated by dislocation slip.•Twinning occurs only during low strain cold rolling.•Dynamic recrystallization is primary mechanism responsible for grain refinement.
We obtained CO(2-1) observations of seven GRB hosts with the APEX and IRAM 30m telescopes. We analysed these data together with all other hosts with previous CO observations. We obtained detections ...for 3 GRB hosts (980425, 080207, and 111005A) and upper limits for the remaining 4 (031203, 060505, 060814, and 100316D). In our entire sample of 12 CO-observed GRB hosts, 3 are clearly deficient in molecular gas, even taking into account their metallicity (980425, 060814, and 080517). Four others are close to the best-fit line for other star-forming galaxies on the SFR-MH2 plot (051022, 060505, 080207, and 100316D). One host is clearly molecule rich (111005A). Finally, the data for 4 GRB hosts are not deep enough to judge whether they are molecule deficient (000418, 030329, 031203, and 090423). The median value of the molecular gas depletion time, MH2/SFR, of GRB hosts is ~0.3 dex below that of other star-forming galaxies, but this result has low statistical significance. A Kolmogorov-Smirnov test performed on MH2/SFR shows an only ~2sigma difference between GRB hosts and other galaxies. This difference can partly be explained by metallicity effects, since the significance decreases to ~1sigma for MH2/SFR versus~metallicity. We found that any molecular gas deficiency of GRB hosts has low statistical significance and that it can be attributed to their lower metallicities; and thus the sample of GRB hosts has molecular properties that are consistent with those of other galaxies, and they can be treated as representative star-forming galaxies. Given the concentration of atomic gas recently found close to GRB and supernova sites, indicating recent gas inflow, our results about the weak molecular deficiency imply that such an inflow does not enhance the SFRs significantly, or that atomic gas converts efficiently into the molecular phase, which fuels star formation.
In the Horn of Africa, little is known about temporal changes in hydroclimate owing to the influence of multiple weather systems, the complex terrain, and the sparse instrumental records. Absolutely ...dated tree-ring records offer the potential to extend our understanding of climate into the pre-instrumental era, but tree-ring studies in this region, and indeed all of tropical Africa, have been rare largely due to lack of an annual climate cycle that reliably produces annual tree-rings. In this study, 40 cores were obtained from 31
Juniperus procera
trees growing in the grounds of Ethiopian Orthodox Tewahedo churches in the Gonder region of Ethiopia. The samples were cross-dated using a re-iterative process involving identifying anatomical features from high-resolution images. The tentative ring-width chronologies were revised after the determination of bomb-peak accelerator mass spectrometry radiocarbon dates. Individual series were significantly correlated to the respective master chronologies (r > 0.55;
P
< 0.05), and expressed population signal values ranged from 0.55 to 0.92. Historical drought years were successfully traced in the chronologies by pointer year analysis. This study confirms that
Juniperus procera
growing in areas of unimodal precipitation exhibits annual tree-rings and offers the potential as an indirect measure of past climate.
We present new empirical constraints on the evolution of \(\rho_{\rm H_2}\), the cosmological mass density of molecular hydrogen, back to \(z\approx2.5\). We employ a statistical approach measuring ...the average observed \(850\mu{\rm m}\) flux density of near-infrared selected galaxies as a function of redshift. The redshift range considered corresponds to a span where the \(850\mu{\rm m}\) band probes the Rayleigh-Jeans tail of thermal dust emission in the rest-frame, and can therefore be used as an estimate of the mass of the interstellar medium (ISM). Our sample comprises of \({\approx}150,000\) galaxies in the UKIDSS-UDS field with near-infrared magnitudes \(K_{\rm AB}\leq25\) mag and photometric redshifts with corresponding probability distribution functions derived from deep 12-band photometry. With a sample approximately 2 orders of magnitude larger than in previous works we significantly reduce statistical uncertainties on \(\rho_{\rm H_2}\) to \(z\approx2.5\). Our measurements are in broad agreement with recent direct estimates from blank field molecular gas surveys, finding that the epoch of molecular gas coincides with the peak epoch of star formation with \(\rho_{\rm H_2}\approx2\times10^7\,{\rm M_\odot}\,{\rm Mpc^{-3}}\) at \(z\approx2\). We demonstrate that \(\rho_{\rm H_2}\) can be broadly modelled by inverting the star-formation rate density with a fixed or weakly evolving star-formation efficiency. This 'constant efficiency' model shows a similar evolution to our statistically derived \(\rho_{\rm H_2}\), indicating that the dominant factor driving the peak star formation history at \(z\approx2\) is a larger supply of molecular gas in galaxies rather than a significant evolution of the star-formation rate efficiency within individual galaxies.
Huott et al describe the overall test methodology used in implementing the S/390 microprocessor and the associated L2 cache array in shared multiprocessor designs, the design-for-test ...implementations, and the test software used in creating the test patterns and in measuring test effectiveness.
Inoculation of rabbits and mice with a vaccinia-rabies glycoprotein recombinant (V-RG) virus resulted in rapid induction of high concentrations of rabies virus-neutralizing antibodies and protection ...from severe intracerebral challenge with several strains of rabies virus. Protection from virus challenge also was achieved against the rabies-related Duvenhage virus but not against the Mokola virus. Effective immunization by V-RG depended on the expression of a rabies glycoprotein that registered proline rather than leucine as the eighth amino acid from its NH2terminus (V-RGpro8). A minimum dose required for effective immunization of mice was 104plaque-forming units of V-RGpro8 virus. β -propiolactone-in-activated preparations of V-RGpro8 virus also induced high levels of rabies virus-neutralizing antibody and protected mice against intracerebral challenge with street rabies virus. V-RGpro8 virus was highly effective in priming mice to generate a secondary rabies virus-specific cytotoxic T-lymphocyte response following culture of lymphocytes with either ERA or PM strains of rabies virus.
We present a new measurement of the evolving galaxy far-IR luminosity function (LF) extending out to redshifts z~5, with resulting implications for the level of dust-obscured star-formation density ...in the young Universe. To achieve this we have exploited recent advances in sub-mm/mm imaging with SCUBA-2 on the James Clerk Maxwell Telescope (JCMT) and the Atacama Large Millimeter/Submillimeter Array (ALMA), which together provide unconfused imaging with sufficient dynamic range to provide meaningful coverage of the luminosity-redshift plane out to z>4. Our results support previous indications that the faint-end slope of the far-IR LF is sufficiently flat that comoving luminosity-density is dominated by bright objects (~L*). However, we find that the number-density/luminosity of such sources at high redshifts has been severely over-estimated by studies that have attempted to push the highly-confused Herschel SPIRE surveys beyond z~2. Consequently we confirm recent reports that cosmic star-formation density is dominated by UV-visible star formation at z>4. Using both direct (1/Vmax) and maximum likelihood determinations of the LF, we find that its high-redshift evolution is well characterized by continued positive luminosity evolution coupled with negative density evolution (with increasing redshift). This explains why bright sub-mm sources continue to be found at z>5, even though their integrated contribution to cosmic star-formation density at such early times is very small. The evolution of the far-IR galaxy LF thus appears similar in form to that already established for active galactic nuclei, possibly reflecting a similar dependence on the growth of galaxy mass.
Conservation of the last remaining Ganges River dolphins Platanista gangetica gangetica in Nepal will require robust population estimates and better information on suitable habitat characteristics. ...To gain a better understanding of these parameters, we conducted boatbased surveys in the 3 major river systems (Karnali, Sapta Koshi, and Narayani) of Nepal. We recorded covariates at high spatial resolution and utilized these data to inform occurrence and abundance models. We allowed for detection bias by applying occupancy and N-mixture models that account for imperfect and heterogeneous detection. Occupancy results indicate that dolphin site use varies among the different river systems, across 2 seasons, and increases with river depth. River effects received nearly 100% of the model support and had the strongest influence on dolphin occurrence and abundance. The seasonal influence on dolphin occurrence in the systems ( capital sigma omega sub(i) = 0.997) revealed that occupancy probabilities were heightened during the pre-monsoon season. Deep pool habitat was also identified as a predictor of dolphin habitat use, which accounted for 41.02% of all dolphin sightings occurring in this habitat. Although estimates vary depending on season, we estimate that there are between 37 and 42 (95% CI: 28 to 52) Ganges River dolphins distributed in the rivers of Nepal. Results suggest that seasonality and each specific river affect dolphins and their habitat in Nepal; we strongly recommend site and season-specific conservation actions. Further research on the integration of additional and alternative abundance techniques, behavioral studies, and pursuit of a conservat
PDF
