862 research outputs found
What Causes High Resistivity in CdTe
CdTe can be made semi-insulating by shallow donor doping. This is routinely
done to obtain high resistivity in CdTe-based radiation detectors. However, it
is widely believed that the high resistivity in CdTe is due to the Fermi level
pinning by native deep donors. The model based on shallow donor compensation of
native acceptors was dismissed based on the assumption that it is practically
impossible to control the shallow donor doping level so precisely that the free
carrier density can be brought below the desired value suitable for radiation
detection applications. In this paper, we present our calculations on carrier
statistics and energetics of shallow donors and native defects in CdTe. Our
results show that the shallow donor can be used to reliably obtain high
resistivity in CdTe. Since radiation detection applications require both high
resistivity and good carrier transport, one should generally use shallow donors
and shallow acceptors for carrier compensation and avoid deep centers that are
effective carrier traps
A Carleman type theorem for proper holomorphic embeddings
In 1927, Carleman showed that a continuous, complex-valued function on the
real line can be approximated in the Whitney topology by an entire function
restricted to the real line. In this paper, we prove a similar result for
proper holomorphic embeddings. Namely, we show that a proper \cC^r embedding
of the real line into \C^n can be approximated in the strong \cC^r topology
by a proper holomorphic embedding of \C into \C^n
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Hydrodynamic Luminescence in a Model Diesel Injector Return Valve
A sample of unadditized diesel fuel was passed through an optically accessible model diesel injector return valve, which consisted of two successive nozzles connected to an intermediate fuel gallery. The first nozzle was cylindrical, while the second nozzle was stepped. The fuel was observed to produce a multi-phase, cavitating flow and a luminous blue-violet emission at the entrance to the second nozzle hole. The flow in the upstream intermediate fuel gallery and the first nozzle hole remained single-phase. Spectral analysis of the luminous emission revealed a spectrum with thermal features containing broad spectral lines and peaks at 358 nm, 389 nm, 405 nm, 412 nm, 430 nm and 475 nm, suggesting that the emission was dominated by π* → π transitions in the alkylated mono-, di-, and tri-aromatics, with additional spectral contributions from CH, C2, C3 and hydrogen (H)
Support for collective action against refugees: The role of national, European, and global identifications, and autochthony beliefs
To understand recent anti-refugee protests in Europe, we examined how different levels of inclusiveness of group identities (national, European, and global) are related to intentions to protest among native Europeans. We focused on the mediating role of autochthony (a belief that the first inhabitants of a territory are more entitled) and the moderating role of threat. Survey data from 11 European countries (N=1909) showed that national identification was positively associated with autochthony, and therefore, with the intention to protest against refugees. In contrast, global identification was related to lower protest intentions via lower autochthony. These paths were found only among Europeans who perceived refugees as a threat. European identification was not related to the endorsement of autochthony or to collective action. These findings indicate why and when majority members are willing to participate in collective action against refugees, and underscore the importance of global identification in the acceptance of refugees
Brucellosis remains a neglected disease inthe developing world: a call forinterdisciplinary action
Brucellosis places significant burdens on the human healthcare system and limits the economic growth of individuals, communities, and nations where such development is especially important to diminish the prevalence of poverty. The implementation of public policy focused on mitigating the socioeconomic effects of brucellosis in human and animal populations is desperately needed. When developing a plan to mitigate the associated consequences, it is vital to consider both the abstract and quantifiable effects. This requires an interdisciplinary and collaborative, or One Health, approach that consists of public education, the development of an infrastructure for disease surveillance and reporting in both veterinary and medical fields, and campaigns for control in livestock and wildlife species
On Uniformly Sampling Traces of a Transition System (Extended Version)
A key problem in constrained random verification (CRV) concerns generation of
input stimuli that result in good coverage of the system's runs in targeted
corners of its behavior space. Existing CRV solutions however provide no formal
guarantees on the distribution of the system's runs. In this paper, we take a
first step towards solving this problem. We present an algorithm based on
Algebraic Decision Diagrams for sampling bounded traces (i.e. sequences of
states) of a sequential circuit with provable uniformity (or bias) guarantees,
while satisfying given constraints. We have implemented our algorithm in a tool
called TraceSampler. Extensive experiments show that TraceSampler outperforms
alternative approaches that provide similar uniformity guarantees.Comment: Extended version of paper that will appear in proceedings of
International Conference on Computer-Aided Design (ICCAD '20); changed wrong
text color in sec 7; added 'extended version
Probing seed black holes using future gravitational-wave detectors
Identifying the properties of the first generation of seeds of massive black
holes is key to understanding the merger history and growth of galaxies.
Mergers between ~100 solar mass seed black holes generate gravitational waves
in the 0.1-10Hz band that lies between the sensitivity bands of existing
ground-based detectors and the planned space-based gravitational wave detector,
the Laser Interferometer Space Antenna (LISA). However, there are proposals for
more advanced detectors that will bridge this gap, including the third
generation ground-based Einstein Telescope and the space-based detector DECIGO.
In this paper we demonstrate that such future detectors should be able to
detect gravitational waves produced by the coalescence of the first generation
of light seed black-hole binaries and provide information on the evolution of
structure in that era. These observations will be complementary to those that
LISA will make of subsequent mergers between more massive black holes. We
compute the sensitivity of various future detectors to seed black-hole mergers,
and use this to explore the number and properties of the events that each
detector might see in three years of observation. For this calculation, we make
use of galaxy merger trees and two different seed black hole mass distributions
in order to construct the astrophysical population of events. We also consider
the accuracy with which networks of future ground-based detectors will be able
to measure the parameters of seed black hole mergers, in particular the
luminosity distance to the source. We show that distance precisions of ~30% are
achievable, which should be sufficient for us to say with confidence that the
sources are at high redshift.Comment: 14 pages, 6 figures, 2 tables, accepted for proceedings of 13th GWDAW
meetin
Virgo calibration and reconstruction of the gravitational wave strain during VSR1
Virgo is a kilometer-length interferometer for gravitational waves detection
located near Pisa. Its first science run, VSR1, occured from May to October
2007. The aims of the calibration are to measure the detector sensitivity and
to reconstruct the time series of the gravitational wave strain h(t). The
absolute length calibration is based on an original non-linear reconstruction
of the differential arm length variations in free swinging Michelson
configurations. It uses the laser wavelength as length standard. This method is
used to calibrate the frequency dependent response of the Virgo mirror
actuators and derive the detector in-loop response and sensitivity within ~5%.
The principle of the strain reconstruction is highlighted and the h(t)
systematic errors are estimated. A photon calibrator is used to check the sign
of h(t). The reconstructed h(t) during VSR1 is valid from 10 Hz up to 10 kHz
with systematic errors estimated to 6% in amplitude. The phase error is
estimated to be 70 mrad below 1.9 kHz and 6 micro-seconds above.Comment: 8 pages, 8 figures, proceedings of Amaldi 8 conference, to be
published in Journal of Physics Conference Series (JPCS). Second release:
correct typo
Calibration and sensitivity of the Virgo detector during its second science run
The Virgo detector is a kilometer-length interferometer for gravitational
wave detection located near Pisa (Italy). During its second science run (VSR2)
in 2009, six months of data were accumulated with a sensitivity close to its
design. In this paper, the methods used to determine the parameters for
sensitivity estimation and gravitational wave reconstruction are described. The
main quantities to be calibrated are the frequency response of the mirror
actuation and the sensing of the output power. Focus is also put on their
absolute timing. The monitoring of the calibration data as well as the
parameter estimation with independent techniques are discussed to provide an
estimation of the calibration uncertainties. Finally, the estimation of the
Virgo sensitivity in the frequency-domain is described and typical
sensitivities measured during VSR2 are shown.Comment: 30 pages, 23 figures, 1 table. Published in Classical and Quantum
Gravity (CQG), Corrigendum include
ASSESSMENT OF STROBILURIN RESISTANCE IN CERCOSPORA BETICOLA ON SUGAR BEET IN MICHIGAN AND NEBRASKA, USA
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