Characterization and deposition of aerosol organic matter in the eastern United States

Aerosol organic carbon (OC) was characterized in two eastern United States watersheds to investigate the potential importance of aerosol OC in watershed OC budgets and cycling. Fluxes of 1.7 and 2.1 mg aerosol OC m-2 d-1 were measured for aerosol samples in Harcum, VA and Millbrook, NY, respectively. Scaled to the area of nearby watersheds (York River watershed, VA and Hudson River watershed, NY) these fluxes are similar in magnitude or greater than the magnitude of riverine OC exported by corresponding rivers indicating that aerosols must be taken into account when thinking about biogeochemical exchanges between the atmospheric, terrestrial, and aquatic realms. Fossil fuel and contemporary biomass emissions are the major sources of aerosol total OC (TOC) to the eastern United States, and radiocarbon signatures were used to estimate the relative contributions from these two sources. On average 33% of aerosol TOC could be attributed to fossil sources throughout the year with mean seasonal fossil TOC contributions (11% to 57% fossil) revealing significant heterogeneity in the relative magnitude of anthropogenic fossil and contemporary biomass TOC sources throughout the year. The 33% fossil aerosol TOC corresponds to a human-derived, 50% increase in aerosol TOC delivered to watersheds and aquatic systems above pre-industrial levels. The effects of such an increase in the delivery of TOC to watersheds are unknown and warrant further investigation. Further radiocarbon analyses on aerosol TOC sub-fractions showed the water-soluble component of aerosol OC (WSOC) to contain significantly more contemporary-aged OC than either bulk aerosol OC or its water-insoluble components. These differences represent a fundamental partitioning in the solubility of fossil and contemporary-derived aerosol OC, and its potential post-depositional fate in watersheds and soils. Fossil OC remains in the less bioavailable particulate phase and its transport is dependent on the erodibility of particles. Molecular characterization of WSOC revealed it to be a highly complex mixture of thousands of compounds including organosulfur compounds not previously recognized to be quantitatively important in the atmosphere. Several elemental formulas consistent with previously identified secondary organic aerosol compounds were present in high abundance providing evidence for the importance of the production of aerosol WSOC via atmospheric processing. Black carbon was present at levels within WSOC that could not explain the 12-14% fossil contributions to WSOC observed in radiocarbon analyses suggesting that some other water-soluble compounds must account for the fossil OC. Collectively, the characterization of the amounts and isotopic and molecular characteristics of aerosol OC presented here provide a foundation on which future studies of the inputs and fates of aerosol OC within watersheds and aquatic systems may be based. Significant quantities of both fossil and contemporary-derived OC are delivered to watersheds representing a potentially important allochthonous source of OC to aquatic systems that should be considered in future studies

Triple Bars and Complex Central Structures in Disk Galaxies

We present an analysis of ground-based and HST images of three early-type barred galaxies. The first, NGC 2681, may be the clearest example yet of a galaxy with three concentric bars. The two other galaxies were previously suggested as triple-barred. Our analysis shows that while NGC 3945 is probably double-barred, NGC 4371 has only one bar; but both have intriguing central structures. NGC 3945 has a large, extremely bright disk inside its primary bar, with patchy dust lanes, a faint nuclear ring or pseudo-ring within the disk, and an apparent secondary bar crossing the ring. NGC 4371 has a bright nuclear ring only marginally bluer than the surrounding bulge and bar. There is no evidence for significant dust or star formation in either of these nuclear rings. The presence of stellar nuclear rings suggests that the centers of these galaxies are dynamically cool and disklike.Comment: LaTeX: 6 pages, 3 figures, uses emulateapj.sty. Accepted by Astrophysical Journal Letters. Version with full-resolution figures available at: http://www.astro.wisc.edu/~erwin/research

Many-Task Computing and Blue Waters

This report discusses many-task computing (MTC) generically and in the context of the proposed Blue Waters systems, which is planned to be the largest NSF-funded supercomputer when it begins production use in 2012. The aim of this report is to inform the BW project about MTC, including understanding aspects of MTC applications that can be used to characterize the domain and understanding the implications of these aspects to middleware and policies. Many MTC applications do not neatly fit the stereotypes of high-performance computing (HPC) or high-throughput computing (HTC) applications. Like HTC applications, by definition MTC applications are structured as graphs of discrete tasks, with explicit input and output dependencies forming the graph edges. However, MTC applications have significant features that distinguish them from typical HTC applications. In particular, different engineering constraints for hardware and software must be met in order to support these applications. HTC applications have traditionally run on platforms such as grids and clusters, through either workflow systems or parallel programming systems. MTC applications, in contrast, will often demand a short time to solution, may be communication intensive or data intensive, and may comprise very short tasks. Therefore, hardware and software for MTC must be engineered to support the additional communication and I/O and must minimize task dispatch overheads. The hardware of large-scale HPC systems, with its high degree of parallelism and support for intensive communication, is well suited for MTC applications. However, HPC systems often lack a dynamic resource-provisioning feature, are not ideal for task communication via the file system, and have an I/O system that is not optimized for MTC-style applications. Hence, additional software support is likely to be required to gain full benefit from the HPC hardware

New Wave of Component Reuse with Spring Framework - AP Case Study

The myth of component reuse has always been the “holy grail” of software engineering. The motivation var-ies from less time, effort and money expenditure to higher system quality and reliability which is especially impor-tant in the domain of high energy physics and accelerator controls. Identified as an issue by D. McIlroy in 1968 [1], it has been generally addressed in many ways with vari-ous success rates. But only recently with the advent of fresh ideas like the Spring Framework with its powerful yet simple “Inversion of Control” paradigm the solution to the problem has started to be surprisingly uncompli-cated. Gathered over years of experience this document explains best practices and lessons learned applied at CERN for the design of the operational software used to control the accelerator complex and focuses on features of the Spring Framework that render the component reuse achievable in practice. It also provides real life use cases of mission-critical control systems developed by the Ap-plication Section like the LHC Software Architecture (LSA), the Injector Control Architecture (InCA) or the Software Interlock System (SIS) that have built their own success mostly upon a stack of reusable software components

Bone marrow transplantation alters the tremor phenotype in the murine model of globoid-cell leukodystrophy

Tremor is a prominent phenotype of the twitcher mouse, an authentic genetic model of Globoid-Cell Leukodystrophy (GLD, Krabbe’s disease). In the current study, the tremor was quantified using a force-plate actometer designed to accommodate low-weight mice. The actometer records the force oscillations caused by a mouse’s movements, and the rhythmic structure of the force variations can be revealed. Results showed that twitcher mice had significantly increased power across a broad band of higher frequencies compared to wildtype mice. Bone marrow transplantation (BMT), the only available therapy for GLD, worsened the tremor in the twitcher mice and induced a measureable alteration of movement phenotype in the wildtype mice. These data highlight the damaging effects of conditioning radiation and BMT in the neonatal period. The behavioral methodology used herein provides a quantitative approach for assessing the efficacy of potential therapeutic interventions for Krabbe’s disease