13,727 research outputs found
Concentrations of Polychlorinated Biphenyls (PCBs), Polychlorinated Dibenzo-p-dioxins and Furans (PCDD/Fs), and Polybrominated Diphenyl Ethers (PBDEs) as Functions of Sample Depth in Killer Whale (Orcinus orca) Blubber
Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs) were examined as a function of depth in killer whale (Orcinus orca) blubber samples. Lipid-normalized concentrations of PCBs, PCDD/Fs, and PBDEs did not display significant variation with depth in three distinct blubber layers (outer, central, and inner). Significantly more variation in contaminant concentrations were observed with depth on a wet weight basis for the killer whale sample. The current study indicates that non-invasive microdart biopsy sampling methods commonly used for monitoring contaminants in marine mammals yield representative details on contaminant burdens for chlorinated and brominated aromatic compounds in marine mammal blubber, regardless of the quantity and type of blubber sampled, provided that lipid normalization is performed on resulting analytical determinations
Assessment of semicircular canal function. Part 1 - Measurements of subjective effects produced by triangular waveforms of angular velocity
Nystagmus and sensation of rotation from semicircular canal stimulation by triangular waveforms of angular velocit
Immune cells and preterm labour:do invariant NKT cells hold the key?
We have developed our original made-to-measure (M2M) algorithm, PRIMAL, with the aim of modelling the Galactic disc from upcoming Gaia data. From a Milky Way like N-body disc galaxy simulation, we have created mock Gaia data using M0III stars as tracers, taking into account extinction and the expected Gaia errors. In PRIMAL, observables calculated from the N-body model are compared with the target stars, at the position of the target stars. Using PRIMAL, the masses of the N-body model particles are changed to reproduce the target mock data, and the gravitational potential is automatically adjusted by the changing mass of the model particles. We have also adopted a new resampling scheme for the model particles to keep the mass resolution of the N-body model relatively constant. We have applied PRIMAL to this mock Gaia data and we show that PRIMAL can recover the structure and kinematics of a Milky Way like barred spiral disc, along with the apparent bar structure and pattern speed of the bar despite the galactic extinction and the observational errors
An n-sided polygonal model to calculate the impact of cyber security events
This paper presents a model to represent graphically the impact of cyber
events (e.g., attacks, countermeasures) in a polygonal systems of n-sides. The
approach considers information about all entities composing an information
system (e.g., users, IP addresses, communication protocols, physical and
logical resources, etc.). Every axis is composed of entities that contribute to
the execution of the security event. Each entity has an associated weighting
factor that measures its contribution using a multi-criteria methodology named
CARVER. The graphical representation of cyber events is depicted as straight
lines (one dimension) or polygons (two or more dimensions). Geometrical
operations are used to compute the size (i.e, length, perimeter, surface area)
and thus the impact of each event. As a result, it is possible to identify and
compare the magnitude of cyber events. A case study with multiple security
events is presented as an illustration on how the model is built and computed.Comment: 16 pages, 5 figures, 2 tables, 11th International Conference on Risks
and Security of Internet and Systems, (CRiSIS 2016), Roscoff, France,
September 201
The Impact of the Safeguard Anti-Ballistic Missile System Construction on Northeastern North Dakota
Federal defense projects have let to rapid population changes in many communities. These communities often have experienced rapid growth during the construction and installation phase, followed by a population decrease when the project became operational and labor requirements declined. Large industrial construction projects (e.g., construction of coal conversion plants) may confront other communities with similar adjustment problems.Community/Rural/Urban Development,
Supercurrent-induced temperature gradient across a nonequilibrium SNS Josephson junction
Using tunneling spectroscopy, we have measured the local electron energy
distribution function in the normal part of a superconductor-normal
metal-superconductor (SNS) Josephson junction containing an extra lead to a
normal reservoir. In the presence of simultaneous supercurrent and injected
quasiparticle current, the distribution function exhibits a sharp feature at
very low energy. The feature is odd in energy, and odd under reversal of either
the supercurrent or the quasiparticle current direction. The feature represents
an effective temperature gradient across the SNS Josephson junction that is
controllable by the supercurrent.Comment: 4 pages, 4 figures, corrected typos, added plot to figure
Effect of Magnetic Impurities on Energy Exchange between Electrons
In order to probe quantitatively the effect of Kondo impurities on energy
exchange between electrons in metals, we have compared measurements on two
silver wires with dilute magnetic impurities (manganese) introduced in one of
them. The measurement of the temperature dependence of the electron phase
coherence time on the wires provides an independent determination of the
impurity concentration. Quantitative agreement on the energy exchange rate is
found with a theory by G\"{o}ppert et al. that accounts for Kondo scattering of
electrons on spin-1/2 impurities.Comment: 4 page
Inelastic cotunneling induced decoherence and relaxation, charge and spin currents in an interacting quantum dot under a magnetic field
We present a theoretical analysis of several aspects of nonequilibirum
cotunneling through a strong Coulomb-blockaded quantum dot (QD) subject to a
finite magnetic field in the weak coupling limit. We carry this out by
developing a generic quantum Heisenberg-Langevin equation approach leading to a
set of Bloch dynamical equations which describe the nonequilibrium cotunneling
in a convenient and compact way. These equations describe the time evolution of
the spin variables of the QD explicitly in terms of the response and
correlation functions of the free reservoir variables. This scheme not only
provides analytical expressions for the relaxation and decoherence of the
localized spin induced by cotunneling, but it also facilitates evaluations of
the nonequilibrium magnetization, the charge current, and the spin current at
arbitrary bias-voltage, magnetic field, and temperature. We find that all
cotunneling events produce decoherence, but relaxation stems only from {\em
inelastic} spin-flip cotunneling processes. Moreover, our specific calculations
show that cotunneling processes involving electron transfer (both spin-flip and
non-spin-flip) contribute to charge current, while spin-flip cotunneling
processes are required to produce a net spin current in the asymmetric coupling
case. We also point out that under the influence of a nonzero magnetic field,
spin-flip cotunneling is an energy-consuming process requiring a sufficiently
strong external bias-voltage for activation, explaining the behavior of
differential conductance at low temperature: in particular, the splitting of
the zero-bias anomaly in the charge current and a broad zero-magnitude "window"
of differential conductance for the spin current near zero-bias-voltage.Comment: 15 pages, 5 figures, published version, to appear in Phys. Rev.
Socioeconomic inequalities in childhood exposure to secondhand smoke before and after smoke-free legislation in three UK countries
Background: Secondhand smoke (SHS) exposure is higher among lower socioeconomic status (SES) children. Legislation restricting smoking in public places has been associated with reduced childhood SHS exposure and increased smoke-free homes. This paper examines socioeconomic patterning in these changes.<p></p>
Methods: Repeated cross-sectional survey of 10 867 schoolchildren in 304 primary schools in Scotland, Wales and Northern Ireland. Children provided saliva for cotinine assay, completing questionnaires before and 12 months after legislation.<p></p>
Results: SHS exposure was highest, and private smoking restrictions least frequently reported, among lower SES children. Proportions of saliva samples containing <0.1 ng/ml (i.e. undetectable) cotinine increased from 31.0 to 41.0%. Although across the whole SES spectrum, there was no evidence of displacement of smoking into the home or increased SHS exposure, socioeconomic inequality in the likelihood of samples containing detectable levels of cotinine increased. Among children from the poorest families, 96.9% of post-legislation samples contained detectable cotinine, compared with 38.2% among the most affluent. Socioeconomic gradients at higher exposure levels remained unchanged. Among children from the poorest families, one in three samples contained > 3 ng/ml cotinine. Smoking restrictions in homes and cars increased, although socioeconomic patterning remained.<p></p>
Conclusions Urgent action is needed to reduce inequalities in SHS exposure. Such action should include emphasis on reducing smoking in cars and homes
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