Matching the Local and Cosmic Star Formation Histories

Given the many recent advances in our understanding of the star formation history (SFH) of the Local Group and other nearby galaxies, and in the evolution of star formation with redshift, we present a new comparison of the comoving space density of the star formation rate as a function of look-back time for the Local and Distant Universe. We update the Local SFH derived from the analysis of resolved stellar populations (``fossil records'') in individual nearby galaxies, based on our own estimations as well as available in the literature. While the preliminary comparison of SFHs is found to be broadly consistent, some discrepancies still remain, including an excess of the Local SFR density in the most recent epoch.Comment: 4 pages, slightly revised version from a contribution to 'Galaxies in the Local Volume', Sydney, 8 - 13 July 2007, B. Koribalski and H. Jerjen, ed

PLUTONIUM FINISHING PLANT (PFP) SUB-GRADE EE/CA EVALUATION OF ALTERNATIVES A NEW MODEL

An engineering evaluation/cost analysis (EE/CA) was performed at the Hanford Site's Plutonium Finishing Plant (PFP). The purpose of the EVCA was to identify the sub-grade items to be evaluated; determine the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) hazardous substances through process history and available data; evaluate these hazards; and as necessary, identify the available alternatives to reduce the risk associated with the contaminants. The sub-grade EWCA considered four alternatives for an interim removal action: (1) No Action; (2) Surveillance and Maintenance (S&M); (3) Stabilize and Leave in Place (Stabilization); and (4) Remove, Treat and Dispose (RTD). Each alternative was evaluated against the CERCLA criteria for effectiveness, implementability, and cost

Galaxy And Mass Assembly (GAMA): spectroscopic analysis

The Galaxy And Mass Assembly (GAMA) survey is a multiwavelength photometric and spectroscopic survey, using the AAOmega spectrograph on the Anglo-Australian Telescope to obtain spectra for up to _ 300 000 galaxies over 280 square degrees, to a limiting magnitude of rpet < 19.8mag. The target galaxies are distributed over 0 < z . 0.5 with a median redshift of z _ 0.2, although the redshift distribution includes a small number of systems, primarily quasars, at higher redshifts, up to and beyond z = 1. The redshift accuracy ranges from σv _ 50 kms−1 to σv _ 100 kms−1 depending on the signal-to-noise of the spectrum. Here we describe the GAMA spectroscopic reduction and analysis pipeline. We present the steps involved in taking the raw two-dimensional spectroscopic images through to flux-calibrated one-dimensional spectra. The resulting GAMA spectra cover an observed wavelength range of 3750 . λ . 8850 °A at a resolution of R _ 1300. The final flux calibration is typically accurate to 10 − 20%, although the reliability is worse at the extreme wavelength ends, and poorer in the blue than the red. We present details of the measurement of emission and absorption features in the GAMA spectra. These measurements are characterised through a variety of quality control analyses detailing the robustness and reliability of the measurements. We illustrate the quality of the measurements with a brief exploration of elementary emission line properties of the galaxies in the GAMA sample. We demonstrate the luminosity dependence of the Balmer decrement, consistent with previously published results, and explore further how Balmer decrement varies with galaxy mass and redshift. We also investigate the mass and redshift dependencies of the [NII]/Hα vs [OIII]/Hβ spectral diagnostic diagram, commonly used to discriminate between star forming and nuclear activity in galaxies.Web of Scienc

AN APPROACH TO CHARACTERIZING & EVALUATING ALTERNATIVES FOR THE DECOMMISSIONING OF SUB-GRADE STRUCTURES AT THE PLUTONIUM FINISHING PLANT (PFP)

In 2002, the Richland Operations Office (RL) of the US Department of Energy (DOE), the US Environmental Protection Agency (EPA), and the Washington State Department of Ecology (Ecology) developed milestones for transitioning the Plutonium Finishing Plant (PFP) facility to a clean slab-on-grade configuration. These milestones required developing an engineering evaluation/cost analysis (EF/CA) for the facility's sub-grade structures and installations as part of a series of evaluations intended to provide for the transition of the facility to a clean slab-on-grade configuration. In addition to supporting decisions for interim actions, the analyses of sub-grade structures and installations performed through this EE/CA will contribute to the remedial investigation feasibility study(ies) and subsequently to the final records of decision for the relevant operable units responsible for site closure in the 200 West Area of the Hanford Site

Diffuse supernova neutrinos: oscillation effects, stellar cooling and progenitor mass dependence

We estimate the diffuse supernova neutrino background (DSNB) using the recent progenitor-dependent, long-term supernova simulations from the Basel group and including neutrino oscillations at several post-bounce times. Assuming multi-angle matter suppression of collective effects during the accretion phase, we find that oscillation effects are dominated by the matter-driven MSW resonances, while neutrino-neutrino collective effects contribute at the 5-10% level. The impact of the neutrino mass hierarchy, of the time-dependent neutrino spectra and of the diverse progenitor star population is 10% or less, small compared to the uncertainty of at least 25% of the normalization of the supernova rate. Therefore, assuming that the sign of the neutrino mass hierarchy will be determined within the next decade, the future detection of the DSNB will deliver approximate information on the MSW-oscillated neutrino spectra. With a reliable model for neutrino emission, its detection will be a powerful instrument to provide complementary information on the star formation rate and for learning about stellar physics.Comment: 19 pages, including 4 figures and 1 table. Clarifying paragraphs added; results unchanged. Matches published version in JCA

Panton-Valentine leukocidin associated staphylococcal disease: a cross-sectional study at a London hospital, England

AbstractRecently, there has been international concern at the rapid emergence of highly pathogenic strains of Staphylococcus aureus associated with a toxin called Panton–Valentine leukocidin (PVL). In the UK, these strains are considered to be rare and mainly severe. We estimate the proportion of staphylococcal infections that are caused by strains containing the PVL genes, and describe risk factors for these infections. Three hundred and ninety consecutive S. aureus clinical isolates, submitted for routine diagnostic purposes were screened for PVL genes. Risk factors for infection were identified from the patient medical record. 9.7% (95% CI 7.0–13.1%) of clinical isolates and 20.8% of skin and soft tissue specimens contained the genes for PVL. Methicillin-resistant S. aureus with PVL was rare (0.8% of all isolates) but PVL with methicillin-sensitive S. aureus was common (9.0% of all specimens). PVL infection was more frequent in males (OR 3.0, 95% CI 1.3–7.0), and in young adults aged 20–39 years (OR 3.7, 95% CI 1.3–10.4). Over half of PVL positive S. aureus infections originated in patients based in the community. Community-onset PVL-associated disease is common in the UK and mainly causes skin and soft tissue infections that do not require admission to hospital. Consideration should be given to current infection control strategy, which advocates household contact screening and decolonization on the assumption that PVL-associated disease is rare

ASSESSING CHEMICAL HAZARDS AT THE PLUTONIUM FINISHING PLANT (PFP) FOR PLANNING FUTURE D&D

This paper documents the fiscal year (FY) 2006 assessment to evaluate potential chemical and radiological hazards associated with vessels and piping in the former plutonium process areas at Hanford's Plutonium Finishing Plant (PFP). Evaluations by PFP engineers as design authorities for specific systems and other subject-matter experts were conducted to identify the chemical hazards associated with transitioning the process areas for the long-term layup of PFP before its eventual final decontamination and decommissioning (D and D). D and D activities in the main process facilities were suspended in September 2005 for a period of between 5 and 10 years. A previous assessment conducted in FY 2003 found that certain activities to mitigate chemical hazards could be deferred safely until the D and D of PFP, which had been scheduled to result in a slab-on-grade condition by 2009. As a result of necessary planning changes, however, D and D activities at PFP will be delayed until after the 2009 time frame. Given the extended project and plant life, it was determined that a review of the plant chemical hazards should be conducted. This review to determine the extended life impact of chemicals is called the ''Plutonium Finishing Plant Chemical Hazards Assessment, FY 2006''. This FY 2006 assessment addresses potential chemical and radiological hazard areas identified by facility personnel and subject-matter experts who reevaluated all the chemical systems (items) from the FY 2003 assessment. This paper provides the results of the FY 2006 chemical hazards assessment and describes the methodology used to assign a hazard ranking to the items reviewed

THE TWO-BEAM ACCELERATOR

A Two-Beam Accelerator, in which one of the beams is an intense low energy beam made to undergo free electron lasing and the other beam is a compact bunch of high energy electrons, is shown to be an interesting possibility for a linear collider

High-Energy Cosmology: gamma rays and neutrinos from beyond the galaxy

Our knowledge of the high-energy universe is undergoing a period of rapid change as new astronomical detectors of high-energy radiation start to operate at their design sensitivities. Now is a boomtime for high-energy astrophysics, with new discoveries from Swift and HESS, results from MAGIC and VERITAS starting to be reported, the upcoming launches of the gamma-ray space telescopes GLAST and AGILE, and anticipated data releases from IceCube and Auger. A formalism for calculating statistical properties of cosmological gamma-ray sources is presented. Application is made to model calculations of the statistical distributions of gamma-ray and neutrino emission from (i) beamed sources, specifically, long-duration GRBs, blazars, and extagalactic microquasars, and (ii) unbeamed sources, including normal galaxies, starburst galaxies and clusters. Expressions for the integrated intensities of faint beamed and unbeamed high-energy radiation sources are also derived. A toy model for the background intensity of radiation from dark-matter annihilation taking place in the early universe is constructed. Estimates for the gamma-ray fluxes of local group galaxies, starburst, and infrared luminous galaxies are briefly reviewed. Because the brightest extragalactic gamma-ray sources are flaring sources, and these are the best targets for sources of PeV -- EeV neutrinos and ultra-high energy cosmic rays, rapidly slewing all-sky telescopes like MAGIC and an all-sky gamma-ray observatory beyond Milagro will be crucial for optimal science return in the multi-messenger age.Comment: 10 pages, 3 figs, accepted for publication in the Barcelona Conference on Multimessenger Astronomy; corrected eq. 27, revised Fig. 3, added 2 ref

Cold gas in elliptical galaxies

We explore the evolution of the cold gas (molecular and neutral hydrogen) of elliptical galaxies and merger remnants ordered into a time sequence on the basis of spectroscopic age estimates. We find that the fraction of cold gas in early merger remnants decreases significantly for ~1-2 Gyr, but subsequent evolution toward evolved elliptical systems sees very little change. This trend can be attributed to an initial gas depletion by strong star-formation which subsequently declines to quiescent rates. This explanation is consistent with the merger picture for the formation of elliptical galaxies. We also explore the relation between HI-to-H2 mass ratio and spectroscopic galaxy age, but find no evidence for a statistically significant trend. This suggests little net HI to H2 conversion for the systems in the present sample.Comment: 11 pages, 6 figures, accepted for publication by MNRA