2,383 research outputs found

    Influence of diffusion on models for non-equilibrium wetting

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    It is shown that the critical properties of a recently studied model for non-equilibrium wetting are robust if one extends the dynamic rules by single-particle diffusion on terraces of the wetting layer. Examining the behavior at the critical point and along the phase transition line, we identify a special point in the phase diagram where detailed balance of the dynamical processes is partially broken.Comment: 6 pages, 9 figure

    The glass transition and crystallization kinetic studies on BaNaB9O15 glasses

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    Transparent glasses of BaNaB9O15 (BNBO) were fabricated via the conventional melt-quenching technique. The amorphous and the glassy nature of the as-quenched samples were respectively, confirmed by X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). The glass transition and crystallization parameters were evaluated under non-isothermal conditions using DSC. The correlation between the heating rate dependent glass transition and the crystallization temperatures was discussed and deduced the Kauzmann temperature for BNBO glass-plates and powdered samples. The values of the Kauzmann temperature for the plates and powdered samples were 776 K and 768 K, respectively. Approximation-free method was used to evaluate the crystallization kinetic parameters for the BNBO glass samples. The effect of the sample thickness on the crystallization kinetics of BNBO glasses was also investigated.Comment: 23 pages, 12 figure

    Finite size effects in nonequilibrium wetting

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    Models with a nonequilibrium wetting transition display a transition also in finite systems. This is different from nonequilibrium phase transitions into an absorbing state, where the stationary state is the absorbing one for any value of the control parameter in a finite system. In this paper, we study what kind of transition takes place in finite systems of nonequilibrium wetting models. By solving exactly a microscopic model with three and four sites and performing numerical simulations we show that the phase transition taking place in a finite system is characterized by the average interface height performing a random walk at criticality and does not discriminate between the bounded-KPZ classes and the bounded-EW class. We also study the finite size scaling of the bKPZ universality classes, showing that it presents peculiar features in comparison with other universality classes of nonequilibrium phase transitions.Comment: 14 pages, 6figures, major change

    BUZZARD: A NUMA-Aware In-Memory Indexing System

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    With the availability of large main memory capacities, in-memory index structures have become an important component of modern data management platforms. Current research even suggests index-based query processing as an alternative or supplement for traditional tuple-at-a-time processing models. However, while simple sequential scan operations can fully exploit the high bandwidth provided by main memory, indexes are mainly latency bound and spend most of their time waiting for memory accesses. Considering current hardware trends, the problem of high memory latency is further exacerbated as modern shared-memory multiprocessors with non-uniform memory access (NUMA) become increasingly common. On those NUMA platforms, the execution time of index operations is dominated by memory access latency that increases dramatically when accessing memory on remote sockets. Therefore, good index performance can only be achieved through careful optimization of the index structure to the given topology. BUZZARD is a NUMA-aware in-memory indexing system. Using adaptive data partitioning techniques, BUZZARD distributes a prefix-tree-based index across the NUMA system and hands off incoming requests to worker threads located on each partition's respective NUMA node. This approach reduces the number of remote memory accesses to a minimum and improves cache utilization. In addition, all indexes inside BUZZARD are only accessed by their respective owner, eliminating the need for synchronization primitives like compare-and-swap

    A glycosylphosphatidylinositol-anchored carbonic anhydrase-related protein of Toxoplasma gondii is important for rhoptry biogenesis and virulence

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    Carbonic anhydrase-related proteins (CARPs) have previously been described as catalytically inactive proteins closely related to α-carbonic anhydrases (α-CAs). These CARPs are found in animals (both vertebrates and invertebrates) and viruses as either independent proteins or domains of other proteins. We report here the identification of a new CARP (TgCA_RP) in the unicellular organism Toxoplasma gondii that is related to the recently described η-class CA found in Plasmodium falciparum. TgCA_RP is posttranslationally modified at its C terminus with a glycosylphosphatidylinositol anchor that is important for its localization in intracellular tachyzoites. The protein localizes throughout the rhoptry bulbs of mature tachyzoites and to the outer membrane of nascent rhoptries in dividing tachyzoites, as demonstrated by immunofluorescence and immunoelectron microscopy using specific antibodies. T. gondii mutant tachyzoites lacking TgCA_RP display a growth and invasion phenotype in vitro and have atypical rhoptry morphology. The mutants also exhibit reduced virulence in a mouse model. Our results show that TgCA_RP plays an important role in the biogenesis of rhoptries
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