3,950 research outputs found
Near threshold response of a wave shifted Cerenkov radiator to heavy ions
The response of Pilot 425 to heavy ions with energies less than 600 MeV/amu beta approximately 0.8 is examined both theoretically and experimentally. Measurements are presented from an experiment which employed a Ne-20 beam at many energies below 575 MeV/amu. The signal is assumed to come from three sources: (1) Cerenkov light from the heavy ion, (2) Cerenkov light from secondary electrons, and (3) scintillation of the radiator. It is found that the effective index of refraction is 1.518 and that scintillation is present at a level of approximately 2.7 percent of the Cerenkov signal for beta = 1 for Ne-20. The first of these values differs from values previously quoted in the literature
High resolution Cerenkov and range detectors for balloon-borne cosmic-ray experiment
A combination of an active Cerenkov detector and passive range detectors is proposed for the high resolution measurement of isotopic composition in the neighborhood of iron in the galactic cosmic rays. A large area (4,300 sq cm) Cerenkov counter and passive range detectors were tested. Tests with heavy ions (2.1 GeV/amu C-12, 289 MeV/amu Ar-40, and 594 MeV/amu Ne-20) revealed the spatial uniformity of response of the Cerenkov counter to be better than 1% peak-to-peak. Light collection efficiency is independent of projectile energy and incidence angle to within at least 0.5%. Passive Lexan track recorders to measure range in the presence of the nuclear interaction background which results from stopping particles through 0.9 interaction lengths of matter were also tested. It was found that nuclear interactions produce an effective range straggling distribution only approximately 75% wider than that expected from range straggling alone. The combination of these tested techniques makes possible high mass resolution in the neighborhood of iron
Triggering synchronized oscillations through arbitrarily weak diversity in close-to-threshold excitable media
It is shown that arbitrarily weak (frozen) heterogeneity can induce global
synchronized oscillations in excitable media close to threshold. The work is
carried out on networks of coupled van der Pol-FitzHugh-Nagumo oscillators. The
result is shown to be robust against the presence of internal dynamical noise.Comment: 4 pages (RevTeX 3 style), 5 EPS figures, submitted to Phys. Rev. E
(16 aug 2001
Consumer credit information systems: A critical review of the literature. Too little attention paid by lawyers?
This paper reviews the existing literature on consumer credit reporting, the most extensively used instrument to overcome information asymmetry and adverse selection problems in credit markets. Despite the copious literature in economics and some research in regulatory policy, the legal community has paid almost no attention to the legal framework of consumer credit information systems, especially within the context of the European Union. Studies on the topic, however, seem particularly relevant in view of the establishment of a single market for consumer credit. This article ultimately calls for further legal research to address consumer protection concerns and inform future legislation
Dynamics of a small neutrally buoyant sphere in a fluid and targeting in Hamiltonian systems
We show that, even in the most favorable case, the motion of a small
spherical tracer suspended in a fluid of the same density may differ from the
corresponding motion of an ideal passive particle. We demonstrate furthermore
how its dynamics may be applied to target trajectories in Hamiltonian systems.Comment: See home page http://lec.ugr.es/~julya
Investing in Prevention or Paying for Recovery - Attitudes to Cyber Risk
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Broadly speaking an individual can invest time and effort to avoid becoming victim to a cyber attack and/or they can invest resource in recovering from any attack. We introduce a new game called the pre-vention and recovery game to study this trade-off. We report results from the experimental lab that allow us to categorize different approaches to risk taking. We show that many individuals appear relatively risk loving in that they invest in recovery rather than prevention. We find little difference in behavior between a gain and loss framing
Correlations, deviations and expectations: the Extended Principle of the Common Cause
The Principle of the Common Cause is usually understood to provide causal explanations for probabilistic correlations obtaining between causally unrelated events. In this study, an extended interpretation of the principle is proposed, according to which common causes should be invoked to explain positive correlations whose values depart from the ones that one would expect to obtain in accordance to her probabilistic expectations. In addition, a probabilistic model for common causes is tailored which satisfies the generalized version of the principle, at the same time including the standard conjunctive-fork model as a special case
Robust Magnetic Polarons in Type-II (Zn,Mn)Te Quantum Dots
We present evidence of magnetic ordering in type-II (Zn, Mn) Te quantum dots.
This ordering is attributed to the formation of bound magnetic polarons caused
by the exchange interaction between the strongly localized holes and Mn within
the dots. In our photoluminescence studies, the magnetic polarons are detected
at temperatures up to ~ 200 K, with a binding energy of ~ 40 meV. In addition,
these dots display an unusually small Zeeman shift with applied field (2 meV at
10 T). This behavior is explained by a small and weakly temperature-dependent
magnetic susceptibility due to anti-ferromagnetic coupling of the Mn spins
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