Advanced Grid programming with components: a biometric identification case study

Component-oriented software development has been attracting increasing attention for building complex distributed applications. A new infrastructure supporting this advanced concept is our prototype component framework based on the Grid component model. This paper provides an overview of the component framework and presents a case study where we utilise the component-oriented approach to develop a business process application for a biometric identification system. We then introduce the tools being developed as part of an integrated development environment to enable graphical component-based development of Grid applications. Finally, we report our initial findings and experiences of efficiently using the component framework and set of software tools

Efficient Deadlock Avoidance for Streaming Computation with Filtering

In this report, we show that deadlock avoidance for streaming computations with filtering can be performed efficiently for a large class of DAG topologies. We first give efficient algorithms for dummy interval computation in series-parallel DAGs, then generalize our results to a larger graph family, the CS4DAGs, in which every undirected cycle has exactly one source and one sink. Our results show that, for a large set of application topologies that are both intuitively useful and formalizable, the streaming model with filtering can be implemented safely with reasonable compilation overhead

Fluvial Volumes, Timescales, and Intermittency in Milna Crater, Mars

Ancient lake deposits and valley networks on Mars provide strong evidence that its surface was once modified by liquid water, but the extent of that modification is still debated. Ancient lacustrine deposits in Milna Crater provide insight into the timescale and fluid volume required to construct fluvially derived sedimentary deposits near the Noachian-Hesperian boundary. Placing the lacustrine deposits their regional context in Paran Valles provides a quantitative measurement of the intermittency of large, water-mediated sediment transport events in that region

Germanium Detector with Internal Amplification for Investigation of Rare Processes

Device of new type is suggested - germanium detector with internal amplification. Such detector having effective threshold about 10 eV opens up fresh opportunity for investigation of dark matter, measurement of neutrino magnetic moment, of neutrino coherent scattering at nuclei and for study of solar neutrino problem. Construction of germanium detector with internal amplification and perspectives of its use are described.Comment: 13 pages, latex, 3 figures, report at NANP-99, International Conference on Non-Accelerator Physics, Dubna, Russia, June 29- July 3, 1999. To be published in the Proceeding

Entropic phase separation of linked beads

We study theoretically a model system of a transient network of microemulsion droplets connected by telechelic polymers and explain recent experimental findings. Despite the absence of any specific interactions between either the droplets or polymer chains, we predict that as the number of polymers per drop is increased, the system undergoes a first order phase separation into a dense, highly connected phase, in equilibrium with dilute droplets, decorated by polymer loops. The phase transition is purely entropic and is driven by the interplay between the translational entropy of the drops and the configurational entropy of the polymer connections between them. Because it is dominated by entropic effects, the phase separation mechanism of the system is extremely robust and does not depend on the particlular physical realization of the network. The discussed model applies as well to other polymer linked particle aggregates, such as nano-particles connected with short DNA linkers

Effect of Non-Magnetic Impurities (Zn,Li) in a Hole Doped Spin-Fermion Model for Cuprates

The effect of adding non-magnetic impurities (NMI), such as Zn or Li, to high-Tc cuprates is studied applying Monte Carlo techniques to a spin-fermion model. It is observed that adding Li is qualitatively similar to doping with equal percentages of Sr and Zn. The mobile holes (MH) are trapped by the NMI and the system remains insulating and commensurate with antiferromagnetic (AF) correlations. This behavior persists in the region %NMI > %MH. On the other hand, when %NMI < %MH magnetic and charge incommensurabilities are observed. The vertical or horizontal hole-rich stripes, present when % NMI=0 upon hole doping, are pinned by the NMI and tend to become diagonal, surrounding finite AF domains. The %MH-%NMI plane is investigated. Good agreement with experimental results is found in the small portion of this diagram where experimental data are available. Predictions about the expected behavior in the remaining regions are made.Comment: Four pages with four figures embedded in tex

Electronic Correlations Near a Peierls-CDW Transition

Results of a phenomenological Monte carlo calculation for a 2D electron-phonon Holstein model near a Peierls-CDW transition are presented. Here the zero Matsubara frequency part of the phonon action is dominant and we approximated it by a phenomenological form that as an Ising-like Peierls-CDW transition. The resulting model is studied on a 32 by 32 lattice. The single particle spectral weight A(k,\omega), the density of states N(\omega), and the real part of the conductivity \sigma_1(\omega) all show evidence of a pseudogap which develops in the low-energy electronic degrees of freedom as the Peierls-CDW transition is approachedComment: 14 pages, 7 figure

A circumpolar parasite: Evidence of a cryptic undescribed species of sucking louse, Linognathus sp., collected from Arctic foxes, Vulpes lagopus, in Nunavut (Canada) and Svalbard (Norway)

The North has experienced unprecedented rates of warming over the past few decades, impacting the survival and development of insects and the pathogens that they carry. Since 2019, Arctic foxes from Canada (Nunavut) have been observed with fur loss inconsistent with natural shedding of fur. Adult lice were collected from Arctic foxes from Nunavut (n = 1) and Svalbard (n = 2; Norway) and were identified as sucking lice (suborder Anoplura). Using conventional PCR targeting the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), lice from Canada and Svalbard were 100% similar (8 pooled samples from Nunavut and 3 pooled samples from Svalbard), indicating that there is potential gene flow between ectoparasites on Scandinavian and North American Arctic fox populations. The cox1 sequences of Arctic fox lice and dog sucking lice (Linognathus setosus) had significant differences (87% identity), suggesting that foxes may harbour a cryptic species that has not previously been recognised. Conventional PCR targeting the gltA gene for Bartonella bacteria amplified DNA from an unknown gammaproteobacteria from two pooled louse samples collected from Svalbard foxes. The amplified sequences were 100% identical to each other but were only 78% like Proteus mirabilis reported in GenBank (CP053614), suggesting that lice on Arctic foxes may carry unique microorganisms that have yet to be described.publishedVersio

Degradation of Organics in a Glow Discharge Under Martian Conditions

The primary objective of this project is to understand the consequences of glow electrical discharges on the chemistry and biology of Mars. The possibility was raised some time ago that the absence of organic material and carbonaceous matter in the Martian soil samples studied by the VikinG Landers might be due in part to an intrinsic atmospheric mechanism such as glow discharge. The high probability for dust interactions during Martian dust storms and dust devils, combined with the cold, dry climate of Mars most likely results in airborne dust that is highly charged. Such high electrostatic potentials generated during dust storms on Earth are not permitted in the low-pressure CO2 environment on Mars; therefore electrostatic energy released in the form of glow discharges is a highly likely phenomenon. Since glow discharge methods are used for cleaning and sterilizing surfaces throughout industry, the idea that dust in the Martian atmosphere undergoes a cleaning action many times over geologic time scales appears to be a plausible one