39 research outputs found

    Results of instrumental aerial survey of ice-associated seals on the ice in the Okhotsk Sea in May 2013

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    Populations of ice-associated seals in the Okhotsk Sea are assessed using modern instrumental aerial technique. The aerial survey was conducted over a part of the ice-covered area of the Sea on May 1-9, 2013 by means of thermal scan and visual digital photography from the aircraft-laboratory An-38 «Vostok». The ice covered area of the Okhotsk Sea in the time of survey was estimated as 242,000 km2, and 2,993 km2 of it was covered by survey transects with total length 5,617 km. The number of animals on all transects within the equipment swath was counted. Four seal species were identified: bearded, spotted, ribbon, and ringed seals, and their number and distribution were determined. The infra-red scanner recorded 5,730 seals on the ice and 4,360 these animals were photographed including 844 ringed seals, 453 bearded, 721 spotted, 1,805 ribbon, 435 pups non-identified to the species, and 102 non-identified to species adult seals. These assessments were extrapolated over the whole ice-covered area of the Okhotsk Sea using a linear model framework, and the following estimations of the species total abundance were presented (95 % confidence intervals in brackets): 88,253 (64,120-130,320) ringed seals, 39,743 (27,868-60,026) bearded seals, 181,179 (118,392-316,995) ribbon seals, and 84,356 (55,172-113,540) spotted seals. A database on all recorded seals with their «portrait-photos» and accompanying information is created on materials of the aerial survey. The developed instrumental technology can be used as a basis for wider aerial surveys of ice-associated seals in the North Pacific

    Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

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    Synthesis of Optimal Algorithms of Recognition of Group Air Targets in Airborne Radar Systems

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    В статье при байесовском критерии оптимальности синтезированы алгоритмы распознавания на этапе вторичной обработки сигналов численного и типового состава групповой воздушной цели (ГВЦ), характера её полёта в радиолокационных системах (РЛС) воздушного базирования, построенных по импульсно-доплеровскому (ИД) принципу обработки сигналов с длительным временем их когерентного накопления. При этом предполагается, что имеется информация о состоянии ГВЦ, полученная в результате обработки сигналов в РЛС на этапе первичной обработки радиолокационных (РЛ) сигналов, отражённых от ГВЦ.In the article by Bayesian optimality criteria algorithms for the recognition stage, the secondary signal processing and numerical model of group air targets , the nature of its flight in radar systems , airborne, built by pulse-Doppler (ID) principle of signal processing of a long time coherent accumulation. In this case, it is assumed that there is information about the state of group air targets, the resulting signal processing in radar at the stage of primary processing of radar (radar) signals reflected from the group of air target

    Synthesis of Optimal Algorithms of Recognition of Group Air Targets in Airborne Radar Systems

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    В статье при байесовском критерии оптимальности синтезированы алгоритмы распознавания на этапе вторичной обработки сигналов численного и типового состава групповой воздушной цели (ГВЦ), характера её полёта в радиолокационных системах (РЛС) воздушного базирования, построенных по импульсно-доплеровскому (ИД) принципу обработки сигналов с длительным временем их когерентного накопления. При этом предполагается, что имеется информация о состоянии ГВЦ, полученная в результате обработки сигналов в РЛС на этапе первичной обработки радиолокационных (РЛ) сигналов, отражённых от ГВЦ.In the article by Bayesian optimality criteria algorithms for the recognition stage, the secondary signal processing and numerical model of group air targets , the nature of its flight in radar systems , airborne, built by pulse-Doppler (ID) principle of signal processing of a long time coherent accumulation. In this case, it is assumed that there is information about the state of group air targets, the resulting signal processing in radar at the stage of primary processing of radar (radar) signals reflected from the group of air target

    Direct observation of the dead-cone effect in quantum chromodynamics

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    The direct measurement of the QCD dead cone in charm quark fragmentation is reported, using iterative declustering of jets tagged with a fully reconstructed charmed hadron

    Hyperon signatures in the PANDA experiment at FAIR

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    We present a detailed simulation study of the signatures from the sequential decays of the triple-strange pbar p -> Ω+Ω- -> K+ΛbarK- Λ -> K+pbarπ+K-pπ- process in the PANDA central tracking system with focus on hit patterns and precise time measurement. We present a systematic approach for studying physics channels at the detector level and develop input criteria for tracking algorithms and trigger lines. Finally, we study the beam momentum dependence on the reconstruction efficiency for the PANDA detector

    Direct observation of the dead-cone effect in quantum chromodynamics

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    At particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD) [1]. The vacuum is not transparent to the partons and induces gluon radiation and quark pair production in a process that can be described as a parton shower [2]. Studying the pattern of the parton shower is one of the key experimental tools in understanding the properties of QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass m and energy E, within a cone of angular size m/E around the emitter [3]. A direct observation of the dead-cone effect in QCD has not been possible until now, due to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible bound hadronic states. Here we show the first direct observation of the QCD dead-cone by using new iterative declustering techniques [4, 5] to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD, which is derived more generally from its origin as a gauge quantum field theory. Furthermore, the measurement of a dead-cone angle constitutes the first direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.The direct measurement of the QCD dead cone in charm quark fragmentation is reported, using iterative declustering of jets tagged with a fully reconstructed charmed hadron.In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass mQm_{\rm{Q}} and energy EE, within a cone of angular size mQm_{\rm{Q}}/EE around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics
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