3,887 research outputs found
Significance Arithmetic for Fortran
Significance tracing arithmetic for Fortra
Role of the electric field in surface electron dynamics above the vacuum level
Scanning tunneling spectroscopy (STS) is used to study the dynamics of hot
electrons trapped on a Cu(100) surface in field emission resonances (FER) above
the vacuum level. Differential conductance maps show isotropic electron
interference wave patterns around defects whenever their energy lies within a
surface projected band gap. Their Fourier analysis reveals a broad wave vector
distribution, interpreted as due to the lateral acceleration of hot electrons
in the inhomogeneous tip-induced potential. A line-shape analysis of the
characteristic constant-current conductance spectra permits to establish the
relation between apparent width of peaks and intrinsic line-width of FERs, as
well as the identification of the different broadening mechanisms.Comment: 7 pages, 4 figures, to appear in Phys. Rev.
Signal specific electric potential sensors for operation in noisy environments
Limitations on the performance of electric potential sensors are due to saturation caused by environmental electromagnetic noise. The work described involves tailoring the response of the sensors to reject the main components of the noise, thereby enhancing both the effective dynamic range and signal to noise. We show that by using real-time analogue signal processing it is possible to detect a human heartbeat at a distance of 40 cm from the front of a subject in an unshielded laboratory. This result has significant implications both for security sensing and biometric measurements in addition to the more obvious safety related applications
The role of the spin in quasiparticle interference
Quasiparticle interference patterns measured by scanning tunneling microscopy
(STM) can be used to study the local electronic structure of metal surfaces and
high temperature superconductors. Here, we show that even in non-magnetic
systems the spin of the quasiparticles can have a profound effect on the
interference patterns. On Bi(110), where the surface state bands are not
spin-degenerate, the patterns are not related to the dispersion of the
electronic states in a simple way. In fact, the features which are expected for
the spin-independent situation are absent and the observed interference
patterns can only be interpreted by taking spin-conserving scattering events
into account.Comment: 4 pages, 2 figure
Towards Mapping Competencies through Learning Analytics: Real-time Competency Assessment for Career Direction through Interactive Simulation
Assessment and Evaluation in Higher Education, 201, pp. 1-13
Susceptibility of cat fleas (siphonaptera: Puclicidae) to fipronil and imidacloprid using adult and larval bioassays
© 2014 Entomological Society of America This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact [email protected] monitoring of the susceptibility offleas to insecticides has typically been conducted by exposing adults on treated surfaces. Other methods such as topical applications of insecticides to adults and larval bioassays on treated rearing media have been developed. Unfortunately, baseline responses of susceptible strains of cat flea, Ctenocephalides felis (Bouchè), except for imidacloprid, have not been determined for all on-animal therapies and new classes of chemistry now being used. However, the relationship between adult and larval bioassays of fleas has not been previously investigated. The adult and larval bioassays of fipronil and imidacloprid were compared for both field-collected isolates and laboratory strains. Adult topical bioassays of fipronil and imidacloprid to laboratory strains and field-collected isolates demonstrated that LD50s of fipronil and imidacloprid ranged from 0.11 to 0.40 nanograms per flea and 0.02 to 0.18 nanograms per flea, respectively. Resistance ratios for fipronil and imidacloprid ranged from 0.11 to 2.21. Based on the larval bioassay published for imidacloprid, a larval bioassay was established for fipronil and reported in this article. The ranges of the LC50s of fipronil and imidacloprid in the larval rearing media were 0.07-0.16 and 0.11-0.21 ppm, respectively. Resistance ratios for adult and larval bioassays ranged from 0.11 to 2.2 and 0.58 to 1.75, respectively. Both adult and larval bioassays provided similar patterns for fipronil and imidacloprid. Although the adult bioassays permitted a more precise dosage applied, the larval bioassays allowed for testing isolates without the need to maintain on synthetic or natural hosts.Peer reviewedFinal Published versio
Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption
Explosive energy release is a common phenomenon occurring in magnetized
plasma systems ranging from laboratories, Earth's magnetosphere, the solar
corona and astrophysical environments. Its physical explanation is usually
attributed to magnetic reconnection in a thin current sheet. Here we report the
important role of magnetic flux rope structure, a volumetric current channel,
in producing explosive events. The flux rope is observed as a hot channel prior
to and during a solar eruption from the Atmospheric Imaging Assembly (AIA)
telescope on board the Solar Dynamic Observatory (SDO). It initially appears as
a twisted and writhed sigmoidal structure with a temperature as high as 10 MK
and then transforms toward a semi-circular shape during a slow rise phase,
which is followed by fast acceleration and onset of a flare. The observations
suggest that the instability of the magnetic flux rope trigger the eruption,
thus making a major addition to the traditional magnetic-reconnection paradigm.Comment: 13 pages, 3 figure
Estimation of solar prominence magnetic fields based on the reconstructed 3D trajectories of prominence knots
We present an estimation of the lower limits of local magnetic fields in
quiescent, activated, and active (surges) promineces, based on reconstructed
3-dimensional (3D) trajectories of individual prominence knots. The 3D
trajectories, velocities, tangential and centripetal accelerations of the knots
were reconstructed using observational data collected with a single
ground-based telescope equipped with a Multi-channel Subtractive Double Pass
imaging spectrograph. Lower limits of magnetic fields channeling observed
plasma flows were estimated under assumption of the equipartition principle.
Assuming approximate electron densities of the plasma n_e = 5*10^{11} cm^{-3}
in surges and n_e = 5*10^{10} cm^{-3} in quiescent/activated prominences, we
found that the magnetic fields channeling two observed surges range from 16 to
40 Gauss, while in quiescent and activated prominences they were less than 10
Gauss. Our results are consistent with previous detections of weak local
magnetic fields in the solar prominences.Comment: 14 pages, 12 figures, 1 tabl
The BioGRID Interaction Database: 2011 update
The Biological General Repository for Interaction Datasets (BioGRID) is a public database that archives and disseminates genetic and protein
interaction data from model organisms and humans
(http://www.thebiogrid.org). BioGRID currently holds 347 966
interactions (170 162 genetic, 177 804 protein) curated from both
high-throughput data sets and individual focused studies, as derived
from over 23 000 publications in the primary literature. Complete
coverage of the entire literature is maintained for budding yeast
(Saccharomyces cerevisiae), fission yeast (Schizosaccharomyces pombe)
and thale cress (Arabidopsis thaliana), and efforts to expand curation
across multiple metazoan species are underway. The BioGRID houses 48
831 human protein interactions that have been curated from 10 247
publications. Current curation drives are focused on particular areas
of biology to enable insights into conserved networks and pathways that
are relevant to human health. The BioGRID 3.0 web interface contains
new search and display features that enable rapid queries across
multiple data types and sources. An automated Interaction Management
System (IMS) is used to prioritize, coordinate and track curation
across international sites and projects. BioGRID provides interaction
data to several model organism databases, resources such as Entrez-Gene
and other interaction meta-databases. The entire BioGRID 3.0 data
collection may be downloaded in multiple file formats, including PSI MI
XML. Source code for BioGRID 3.0 is freely available without any
restrictions
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