41 research outputs found

    The fundamental solution and Strichartz estimates for the Schr\"odinger equation on flat euclidean cones

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    We study the Schr\"odinger equation on a flat euclidean cone R+×Sρ1\mathbb{R}_+ \times \mathbb{S}^1_\rho of cross-sectional radius ρ>0\rho > 0, developing asymptotics for the fundamental solution both in the regime near the cone point and at radial infinity. These asymptotic expansions remain uniform while approaching the intersection of the "geometric front", the part of the solution coming from formal application of the method of images, and the "diffractive front" emerging from the cone tip. As an application, we prove Strichartz estimates for the Schr\"odinger propagator on this class of cones.Comment: 21 pages, 4 figures. Minor typos corrected. To be published in Comm. Math. Phy

    Biomphalaria alexandrina snails as immunogens against Schistosoma mansoni infection in mice

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    Despite effective chemotherapy, schistosomiasis remains the second largest public health problem in the developing world. Currently, vaccination is the new strategy for schistosomiasis control. The presence of common antigenic fractions between Schistosoma mansoni and its intermediate host provides a source for the preparation of a proper vaccine. The objective of this paper is to evaluate the nucleoprotein extracted from either susceptible or resistant snails to protect against schistosomiasis. The vaccination schedule consisted of a subcutaneous injection of 50 ”g protein of each antigen followed by another inoculation 15 days later. Analyses of marker enzymes for different cell organelles [succinate dehydrogenase, lactate dehydrogenase (LDH), glucose-6-phosphatase, acid phosphatase and 5'-nucleotidase] were carried out. Energetic parameters (ATP, ADP, AMP, phosphate potentials, inorganic phosphate, amino acids and LDH isoenzymes) were also investigated. The work was extended to record worm and ova counts, oogram determination in the liver and intestine and the histopathological pattern of the liver. The nucleoprotein of susceptible snails showed reduction in worm and ova counts by 70.96% and 51.31%, respectively, whereas the nucleoprotein of resistant snails showed reductions of 9.67% and 16.77%, respectively. In conclusion, we found that the nucleoprotein of susceptible snails was more effective in protecting against schistosomiasis

    The quality-control test of the digital logic for the ATLAS new small wheel read-out controller ASIC

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    The Read-Out Controller (ROC) ASIC is an on-detector custom real-time data packet processor for the upgraded New Small Wheel (NSW) Trigger and Data Acquisition (TDAQ) system of the ATLAS Experiment at CERN, Geneva. The ROC is a highly-configurable data concentrator that allows the optimization of bandwidth utilization, reduces the required number of data links, minimizes data loss, implements congestion and flow control mechanisms, allows data filtering, supplies phase adjustable clock signals and offers relatively larger buffer spaces for the readout system. The paper details the designed, implemented and deployed FPGA-based test setup for the quality-control of the ROC packet processing logic. The FPGA-based test setup emulates the ROC context using firmware-based input data streams emulators and output data analyzers which are controlled and monitored by a soft-core Xilinx MicroBlaze microprocessor instantiated on the same FPGA. The ROC chip is accommodated on a custom PCB which assures the power supply and the interface to the FPGA. A mathematical model of the ROC performance as a function of its configuration and input data throughput is proposed. The ROC digital design was successfully validated and its performance assessed, confirming the theoretical model. The design coverage, test procedure and partial mass-testing results are presented and analyzed

    Evaluation of the Delivery QoS Characteristics of Gigabit Ethernet Switches

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    The event selection system for ATLAS is designed to perform real-time image processing on particle collision data equivalent to 2 TB/s. This data is filtered by a multi-level architecture, resulting in 200 GB/s of data analysed by a distributed system consisting of several thousand PCs and switches. As part of our ongoing work on this system, we performed tests on several Gigabit Ethernet switches manufactured by market leaders, using our custom-built test equipment. We analysed the implications of running network devices at, and just beyond, saturation while deploying service differentiation mechanisms. We quantified the quality degradation that traffic flows experienced when passing through switches. We focused on emergent properties in saturation, including fairness and fidelity to expectations. We discuss the ideals for switch behaviour and compare them against the observed behaviour of real implementations of differentiation mechanisms in switches. This creates a generic benchmark, which is independent of the switch internals

    Network performance measurements as part of feasibility studies on moving an ATLAS event filter to off-site institutes

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    We present a system for measuring network performance as part of the feasibility studies for locating the ATLAS third level trigger, the event filter (EF), in remote locations. Part of the processing power required to run the EF algorithms, the current estimate is 2000 state off the art processors, can be provided in remote, CERN-affiliated institutes, if a suitable network connection between CERN and the remote site could be achieved. The system is composed of two PCs equipped with GPS systems, CERN-designed clock cards and Alteon gigabit programmable network interface cards. In the first set of measurements we plan to quantify connection in terms of end-to-end latency, throughput, jitter and packet loss. Running streaming tests and study throughput, IP QoS, routing testing and traffic shaping follows this. Finally, we plan to install the event filter software in a remote location and feed it with data from test beams at CERN. Each of these tests should be preformed with the test traffic treated in the network on the "best effort" basis and also when the traffic is sent via a 'dedicated' channel. The description of the system initially deployed in CERN-Geneva/Switzerland and Cracow/Poland is followed by results from the first measurements. (4 refs)

    A Holocene record of Pacific Decadal Oscillation (PDO)-related hydrologic variability in Southern California (Lake Elsinore, CA)

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    High-resolution terrestrial records of Holocene climate from Southern California are scarce. Moreover, there are no records of Pacific Decadal Oscillation (PDO) variability, a major driver of decadal to multi-decadal climate variability for the region, older than 1,000 years. Recent research on Lake Elsinore, however, has shown that the lake’s sediments hold excellent potential for paleoenvironmental analysis and reconstruction. New 1-cm contiguous grain size data reveal a more complex Holocene climate history for Southern California than previously recognized at the site. A modern comparison between the twentieth century PDO index, lake level change, San Jacinto River discharge, and percent sand suggests that sand content is a reasonable, qualitative proxy for PDO-related, hydrologic variability at both multi-decadal-to-centennial as well as event (i.e. storm) timescales. A depositional model is proposed to explain the sand-hydrologic proxy. The sand-hydrologic proxy data reveal nine centennial-scale intervals of wet and dry climate throughout the Holocene. Percent total sand values >1.5 standard deviation above the 150–9,700 cal year BP average are frequent between 9,700 and 3,200 cal year BP (n = 41), but they are rare from 3,200 to 150 cal year BP (n = 6). This disparity is interpreted as a change in the frequency of exceptionally wet (high discharge) years and/or changes in large storm activity. A comparison to other regional hydrologic proxies (10 sites) shows more then occasional similarities across the region (i.e. 6 of 9 Elsinore wet intervals are present at >50% of the comparison sites). Only the early Holocene and the Little Ice Age intervals, however, are interpreted consistently across the region as uniformly wet (≄80% of the comparison sites). A comparison to two ENSO reconstructions indicates little, if any, correlation to the Elsinore data, suggesting that ENSO variability is not the predominant forcing of Holocene climate in Southern California
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