48 research outputs found

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

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    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    D* Production in Deep Inelastic Scattering at HERA

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    This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D+(D0Kπ+)π+D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ (+ c.c.) has been used in the study. The e+pe^+p cross section for inclusive D^{*\pm} production with 5<Q2<100GeV25<Q^2<100 GeV^2 and y<0.7y<0.7 is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {1.3<pT(D±)<9.01.3<p_T(D^{*\pm})<9.0 GeV and η(D±)<1.5| \eta(D^{*\pm}) |<1.5}. Differential cross sections as functions of p_T(D^{*\pm}), η(D±),W\eta(D^{*\pm}), W and Q2Q^2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and η\eta(D^{*\pm}), the charm contribution F2ccˉ(x,Q2)F_2^{c\bar{c}}(x,Q^2) to the proton structure function is determined for Bjorken xx between 2 \cdot 104^{-4} and 5 \cdot 103^{-3}.Comment: 17 pages including 4 figure

    Observation of Events with an Energetic Forward Neutron in Deep Inelastic Scattering at HERA

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    In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken x and Q2 in the range 3 · 10-4 \u3c xBJ \u3c 6 · 10-3 and 10 \u3c Q2 \u3c 100 GeV2

    Dynamic traffic management mechanism for active optimization of ISP costs

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    This paper proposes a dynamic traffic management mechanism which addresses the problem of cost-optimal distribution of inevitable inter-domain traffic on multiple links, and enables dynamic overlay traffic management and adaptation to constantly changing traffic patterns to meet cost optimization goals. The mechanism allows for the management of traffic generated by overlay applications such as content delivery platforms, online storage systems, or P2P

    Mechanism for dynamic optimization of inter-domain traffic cost in multi-homed ISP's network

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    This paper proposes a dynamic traffic management (DTM) mechanism which addresses the problem of cost-optimal distribution of inevitable overlay inter-domain traffic on multiple links. The paper extends the DTM mechanism to the 95th percentile charging rule enabling dynamic overlay traffic management and adaptation to constantly changing traffic patterns to meet cost optimization goals. The mechanism allows for the management of traffic generated by overlay applications such as content delivery platforms, online storage systems, or P2P. We discuss simulation results performed for the DTM in case of two inter-domain links charged according to the 95th percentile rule

    Flow-aware multi-topology adaptive routing

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    Internet routing processes currently rely on protocols that were developed more than ten years ago. Today, we have far more computational power and memory at our disposal, and it is possible to take advantage of these resources in order to greatly increase the efficiency of routing protocols. Therefore, we propose a new approach to routing packets in IP-based networks: Flow-Aware Multi-Topology Adaptive Routing, or FAMTAR. FAMTAR combines flow-aware traffic management and an adaptive routing mechanism. A standard routing protocol is used to find the optimal path between two nodes in a network. FAMTAR makes it possible to automatically create additional paths when such demand occurs. Between two endpoints, the transmission may follow n different paths, where n is limited only by the topology of the network. In this letter, we compare FAMTAR to a classic routing protocol and demonstrate FAMTAR's superiority

    Loop resolution mechanism for Flow-Aware Multi-Topology Adaptive Routing

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    Flow-Aware Multi-Topology Adaptive Routing is a new proposal which provides multipath transmissions in the networks based on any IP routing protocol. However, due to utilization of flow tables which store flow forwarding information, it suffers from routing instability and the occurrence of failures. This problem is solved by the mechanism proposed in this letter. The mechanism is based on a Time-To-Live field from the IP protocol header. The mechanism is simple, yet very effective. The evaluation shows that at the cost of additional operations performed by routers the problem is completely eliminated

    Analysis of the selected antioxidant compounds in ice cream supplemented with Spirulina (Arthrospira platensis) extract

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    The research is aimed at evidencing that ice-cream formulations incorporating algae can have health-benefiting effects on human body. The main task of the project is to design ice-cream product line that distinguish itself from regular ice-cream by increased anti-oxidant activity resulted from inclusion of the algae extract. The currently known research evidences that ice-cream can be effective as carriers of health-promoting probiotic bacteria, which in turn encourages also application of other microorganisms in particular algae of specific strains (e.g. Spirulina platensis) as a supplement to ice-cream. In submitted research, the level of polyphenols and antioxidant activity expressed as degree of inhibiting generation of cationo-free radical from DPPH•+ solution were analyzed. Preliminary results based on antioxidative activity tests measured with potential to quench free radicals have shown that ice-cream formulations enriched with algae extract exhibit significantly higher potential achieving inhibition level of 39.7% in the mint ice cream samples as compared to 32.8% inhibition for the control sample without algae. Furthermore, each of the examined samples (dairy, pistachio, mint) ice creams versions supplemented with Spirulina were characterized by enhanced antioxidant activities expressed as potential to quench free radicals and the carotenoids content
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