17,341 research outputs found
Event rates vs. cross sections at neutrino telescopes
One of the major goals of neutrino astronomy is to explore the otherwise
unknown fluxes and interactions of ultrahigh energy neutrinos. The existing
neutrino telescopes look at three types of events: particle showers, muons, and
taus. In this paper we discuss the dependence of the event rates on the
neutrino nucleon cross-sections as we scale the cross sections, with energy, in
different scenarios beyond the standard model. Our focus will be on the IceCube
detector.Comment: 3 pages, 2 figures; proceedings of the "TeV Particle Astrophysics
II", Madison, Wisconsin; to be published in the Journal of Physics:
Conference Serie
Level-crossing rate and average duration of fades for mobile radio channel with hyperbolically distributed scatterers
In this paper we study the geometrical and time-variant wireless vector channel model with hyperbolically distributed scatterers for a macrocell mobile environment. In this study we investigate the level-crossing rate (LCR), the average duration of fades (ADF), the probability density function (PDF), the cumulative distribution function (CDF) and the autocorrelation functions (ACF) of this recently-proposed model. The simulated results are verified against the analytical Clarke's channel model. In this paper we study the geometrical and time-variant wireless vector channel model with hyperbolically distributed scatterers for a macrocell mobile environment. In this study we investigate the level-crossing rate (LCR), the average duration of fades (ADF), the probability density function (PDF), the cumulative distribution function (CDF) and the autocorrelation functions (ACF) of this recently-proposed model. The simulated results are verified against the analytical Clarke's channel model
Towards a register-based census in Oman
ICEGOV 2020: Proceedings of the 13th International Conference on Theory and Practice of Electronic GovernanceA national census is an official count of a country’s population that
aims to motivate and measure sustainable development.
Traditionally, a census is a cumbersome manual operation that
involves distributing surveys to all households in the country
through field agents or by mail. Recently, some countries have
utilized voluntary electronic submissions in addition to the manual
work to reduce costs and increase efficiency. However, an
increasing number of countries are resorting to a register-based
census that uses pre-existing official registers to derive its data.
This paper describes Oman’s upcoming register-based census, e-
Census 2020, and analyses it against the European Commission’s
necessary conditions that facilitate a successful transition from a
traditional to a register-based censusNORTE-01-0145-FEDER-000037. "SmartEGOV: Harnessing
EGOV for Smart Governance (Foundations, methods, Tools) /
NORTE-01-0145-FEDER-000037", supported by Norte Portugal
Regional Operational Programme (NORTE 2020), under the
PORTUGAL 2020 Partnership Agreement, through the European
Regional Development Fund (EFDR
ATR-FTIR spectroscopy detects alterations induced by organotin(IV) carboxylates in MCF-7 cells at sub-cytotoxic/-genotoxic concentrations.
The environmental impact of metal complexes such as organotin(IV) compounds is of increasing concern. Genotoxic effects of organotin(IV) compounds (0.01 μg/ml, 0.1 μg/ml or 1.0 μg/ml) were measured using the alkaline single-cell gel electrophoresis (comet) assay to measure DNA single-strand breaks (SSBs) and the cytokinesis-block micronucleus (CBMN) assay to determine micronucleus formation. Biochemical-cell signatures were also ascertained using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. In the comet assay, organotin(IV) carboxylates induced significantly-elevated levels of DNA SSBs. Elevated micronucleus-forming activities were also observed. Following interrogation using ATR-FTIR spectroscopy, infrared spectra in the biomolecular range (900 cm-1 – 1800 cm-1) derived from organotin-treated MCF-7 cells exhibited clear alterations in their biochemical-cell fingerprint compared to control-cell populations following exposures as low as 0.0001 μg/ml. Mono-, di- or tri-organotin(IV) carboxylates (0.1 μg/ml, 1.0 μg/ml or 10.0 μg/ml) were markedly cytotoxic as determined by the clonogenic assay following treatment of MCF-7 cells with ≥ 1.0 μg/ml. Our results demonstrate that ATR-FTIR spectroscopy can be applied to detect molecular alterations induced by organotin(IV) compounds at sub-cytotoxic and sub-genotoxic concentrations. This biophysical approach points to a novel means of assessing risk associated with environmental contaminants
Magnetic Induction Imaging with Optical Atomic Magnetometers: Towards Applications to Screening and Surveillance
We propose a new approach, based on optical atomic magnetometers and magnetic induction tomography (MIT), for remote and non-invasive detection of conductive targets. Atomic magnetometers overcome the main limitations of conventional MIT instrumentation, in particular their poor low-frequency sensitivity, their large size and their limited scalability. Moreover, atomic magnetometers have been proven to reach extremely high sensitivities, with an improvement of up to 7 orders of magnitude in the 50 MHz to DC band, with respect to a standard pick-up coil of the same size. In the present scheme, an oscillating magnetic field induces eddy currents in a conductive target and laser-pumped atomic magnetometers, either stand-alone or in an array, detect the response of the objects. A phase-sensitive detection scheme rejects the background, allowing remote detection of the secondary field and, thus, mapping of objects, hidden in cargos, underwater or underground. The potential for extreme sensitivity, miniaturization, dynamic range and array operation paves the way to a new generation of non-invasive, active detectors for surveillance, as well as for real-time cargo screening. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
Orientation-dependent C60 electronic structures revealed by photoemission
We observe, with angle-resolved photoemission, a dramatic change in the
electronic structure of two C60 monolayers, deposited respectively on Ag (111)
and (100) substrates, and similarly doped with potassium to half-filling of the
C60 lowest unoccupied molecular orbital. The Fermi surface symmetry, the
bandwidth, and the curvature of the dispersion at Gamma point are different.
Orientations of the C60 molecules on the two substrates are known to be the
main structural difference between the two monolayers, and we present new
band-structure calculations for some of these orientations. We conclude that
orientations play a key role in the electronic structure of fullerides.Comment: 4 pages, 4 figure
Polaronic behavior of undoped high-Tc cuprates
We present angle-resolved photoemission spectroscopy (ARPES) data on undoped
La2CuO4, indicating polaronic coupling between bosons and charge carriers.
Using a shell model, we calculate the electron-phonon coupling and find that it
is strong enough to give polarons. We develop an efficient method for
calculating ARPES spectra in undoped systems. Using the calculated couplings,
we find the width of the phonon side band in good agreement with experiment. We
analyze reasons for the observed dependence of the width on the binding energy.Comment: 4 pages, RevTeX, 5 eps figures, more material available at
http://www.fkf.mpg.de/andersen/phonons
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