4,035 research outputs found
Casimir effects in graphene systems: unexpected power laws
We present calculations of the zero-temperature Casimir interaction between
two freestanding graphene sheets as well as between a graphene sheet and a
substrate. Results are given for undoped graphene and for a set of doping
levels covering the range of experimentally accessible values. We describe
different approaches that can be used to derive the interaction. We point out
both the predicted power law for the interaction and the actual distance
dependence.Comment: 10 pages,5 figures, conferenc
Beneficial and Harmful Agile Practices for Product Quality
There is the widespread belief that Agile neglects the product quality. This
lack of understanding how Agile processes assure the quality of the product
prevents especially companies from regulated domains from an adoption of Agile.
This work aims to identify which Agile Practices contribute towards product
quality. Hence, data from a survey study is analyzed to identify Ag-ile
Practices which are beneficial or harmful for the quality of the product. From
49 practices that were used in the survey so far, 36 were perceived to have a
positive impact on product quality, while four practices were rated as being
harmful. The results enrich understanding of how product quality can be
achieved in Agile, and support selection of practices to improve quality
Palliative balloon dilation of native coarctation of the aorta in a preterm infant
The role of balloon dilation for native coarctation in neonates is controversial, due to
the relatively high recurrence rate. Balloon dilation may however provide adequate
palliation in preterm infants, by relieving symptoms and allowing somatic growth until
definitive surgical repair can be performed. We report successful balloon angioplasty,
on 2 occasions, in a preterm neonate with coarctation of the aorta and associated left
ventricular cardiomyopathy.peer-reviewe
Individual Control of Risk: Seat Belt Use, Subjective Norms and the Theory of Reasoned Action
When faced with a risk for which an inexpensive solution is available, individuals often choose the risk rather than the solution. Protection from certain kinds of risks, e.g., using seat belts or condoms or insulating against radon, is largely under personal control, but individuals often choose not to comply with behaviors which would reduce the risk. The Theory of Reasoned Action (TRA) has been used to predict when individuals will comply. The authors attempted to validate aspects of the TRA by the use of scenarios. Factor analysis of their data supports the theory that intention is a major determinate of behavior but fails to establish the influence of scenarios on subjects\u27 intention to wear seat belts
Anisotropic superexchange of a 90 degree Cu-O-Cu bond
The magnetic anisotropy af a rectangular Cu-O-Cu bond is investigated in
second order of the spin-orbit interaction. Such a bond is characteristic for
cuprates having edge sharing CuO_2 chains, and exists also in the Cu_3O_4 plane
or in ladder compounds. For a ferromagnetic coupling between the copper spins
an easy axis is found perpendicular to the copper oxygen plaquettes in
agreement with the experimental spin structure of Li_2CuO_2. In addition, a
pseudo-dipolar interaction is derived. Its estimation in the case of the
Cu_3O_4 plane (which is present for instance in Ba_2Cu_3O_4Cl_2 or
Sr_2Cu_3O_4Cl_2) gives a value which is however two orders of magnitude smaller
than the usual dipole-dipole interaction.Comment: 6 pages, 2 figures, improved referenc
USCT data challenge 2019
Recent years have witnessed the active development of scanning systems and reconstructionalgorithms for ultrasound computed tomography (USCT) with applications to breast imagingfor early cancer detection. Despite these advances in hardware and software development,we encounter the need for reference data to develop, test and compare different imagingmethods. With the goals of encouraging scientific exchange and collaborations, providingbenchmarks of reconstruction algorithms, and standardizing USCT data formats, we havereleased open-source data sets of simulated waveforms that mimic measurements of a USCTscanning aperture using numerical breast phantoms. This is part of ongoing efforts centeredaround the USCT platform for data exchange and collaboration
Nuclear deformation and neutrinoless double- decay of Zr, Mo, Ru, Pd, Te and Nd nuclei in mass mechanism
The decay of Zr, Mo,
Ru, Pd, Te and Nd isotopes for the
transition is studied in the Projected Hartree-Fock-Bogoliubov
framework. In our earlier work, the reliability of HFB intrinsic wave functions
participating in the decay of the above mentioned nuclei
has been established by obtaining an overall agreement between the
theoretically calculated spectroscopic properties, namely yrast spectra,
reduced : transition probabilities, quadrupole moments
, gyromagnetic factors as well as half-lives
for the transition and the available
experimental data. In the present work, we study the decay for the transition in the mass mechanism
and extract limits on effective mass of light as well as heavy neutrinos from
the observed half-lives using nuclear
transition matrix elements calculated with the same set of wave functions.
Further, the effect of deformation on the nuclear transition matrix elements
required to study the decay in the mass
mechanism is investigated. It is noticed that the deformation effect on nuclear
transition matrix elements is of approximately same magnitude in and decay.Comment: 15 pages, 1 figur
Investigations of fast neutron production by 190 GeV/c muon interactions on different targets
The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus
interactions is poorly understood, yet it is fundamental to the understanding
of the background in many underground experiments. The aim of the present
experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c
muons scattering on carbon, copper and lead targets. We have investigated the
energy spectrum and angular distribution of spallation neutrons, and we report
the result of our measurement of the neutron production differential cross
section.Comment: 19 pages, 11 figures ep
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