1,448 research outputs found
Fully electrically read-write device out of a ferromagnetic semiconductor
We report the realization of a read-write device out of the ferromagnetic
semiconductor (Ga,Mn)As as the first step to fundamentally new information
processing paradigm. Writing the magnetic state is achieved by current-induced
switching and read-out of the state is done by the means of the tunneling
anisotropic magneto resistance (TAMR) effect. This one bit demonstrator device
can be used to design a electrically programmable memory and logic device.Comment: 4 pages, 4 figure
Numerical investigation of a double frequency approach for longitudinal HF welding of cladded pipes
This article contains findings of simulation research on longitudinal induction welding of cladded pipes with use of simultaneous double frequency. Solutions are proposed to reach the required temperature distribution at the welding edge for the cladding composite of S355 and Alloy 625 with single and simultaneous double frequency. An advanced consideration of magnetic and other material properties was performed to simulate the dominating physical effects of high frequency (HF) welding. The background of use and advantages of simultaneous double frequency are presented. In the context of the research, a correlation for welding speed, frequency and temperature distribution with industrial relevance was found for the cladded pipe welding
CPT Violation Implies Violation of Lorentz Invariance
An interacting theory that violates CPT invariance necessarily violates
Lorentz invariance. On the other hand, CPT invariance is not sufficient for
out-of-cone Lorentz invariance. Theories that violate CPT by having different
particle and antiparticle masses must be nonlocal.Comment: Minor changes in the published versio
Hawks and Doves on Small-World Networks
We explore the Hawk-Dove game on networks with topologies ranging from
regular lattices to random graphs with small-world networks in between. This is
done by means of computer simulations using several update rules for the
population evolutionary dynamics. We find the overall result that cooperation
is sometimes inhibited and sometimes enhanced in those network structures, with
respect to the mixing population case. The differences are due to different
update rules and depend on the gain-to-cost ratio. We analyse and qualitatively
explain this behavior by using local topological arguments.Comment: 12 pages, 8 figure
Xenosurveillance reflects traditional sampling techniques for the identification of human pathogens: A comparative study in West Africa
BACKGROUND: Novel surveillance strategies are needed to detect the rapid and continuous emergence of infectious disease agents. Ideally, new sampling strategies should be simple to implement, technologically uncomplicated, and applicable to areas where emergence events are known to occur. To this end, xenosurveillance is a technique that makes use of blood collected by hematophagous arthropods to monitor and identify vertebrate pathogens. Mosquitoes are largely ubiquitous animals that often exist in sizable populations. As well, many domestic or peridomestic species of mosquitoes will preferentially take blood-meals from humans, making them a unique and largely untapped reservoir to collect human blood.
METHODOLOGY/PRINCIPAL FINDINGS: We sought to take advantage of this phenomenon by systematically collecting blood-fed mosquitoes during a field trail in Northern Liberia to determine whether pathogen sequences from blood engorged mosquitoes accurately mirror those obtained directly from humans. Specifically, blood was collected from humans via finger-stick and by aspirating bloodfed mosquitoes from the inside of houses. Shotgun metagenomic sequencing of RNA and DNA derived from these specimens was performed to detect pathogen sequences. Samples obtained from xenosurveillance and from finger-stick blood collection produced a similar number and quality of reads aligning to two human viruses, GB virus C and hepatitis B virus.
CONCLUSIONS/SIGNIFICANCE: This study represents the first systematic comparison between xenosurveillance and more traditional sampling methodologies, while also demonstrating the viability of xenosurveillance as a tool to sample human blood for circulating pathogens
Strong electric fields induced on a sharp stellar boundary
Due to a first order phase transition, a compact star may have a
discontinuous distribution of baryon as well as electric charge densities, as
e.g. at the surface of a strange quark star. The induced separation of positive
and negative charges may lead to generation of supercritical electric fields in
the vicinity of such a discontinuity. We study this effect within a
relativistic Thomas-Fermi approximation and demonstrate that the strength of
the electric field depends strongly on the degree of sharpness of the surface.
The influence of strong electric fields on the stability of compact stars is
discussed. It is demonstrated that stable configurations appear only when the
counter-pressure of degenerate fermions is taken into consideration.Comment: 13 pages, 2 figure
Coevolution of teaching activity promotes cooperation
Evolutionary games are studied where the teaching activity of players can
evolve in time. Initially all players following either the cooperative or
defecting strategy are distributed on a square lattice. The rate of strategy
adoption is determined by the payoff difference and a teaching activity
characterizing the donor's capability to enforce its strategy on the opponent.
Each successful strategy adoption process is accompanied with an increase in
the donor's teaching activity. By applying an optimum value of the increment
this simple mechanism spontaneously creates relevant inhomogeneities in the
teaching activities that support the maintenance of cooperation for both the
prisoner's dilemma and the snowdrift game.Comment: 10 pages, 4 figures; accepted for publication in New Journal of
Physic
The effect of intermittent shedding on prevalence estimation in populations
When studying the epidemiology of an infectious agent such as Salmonella, it is often necessary to estimate infection prevalence. The researcher must measure the amount of infection in those animals, pens, or herds that do or do not have a given exposure experience, e.g. all-in all-out versus continuous ·now. Accurate measurement, or statistical estimation, of the prevalence is important to calculate the relative risk of a management factor. An inaccurate prevalence estimate can be acceptable if it is nondifferential, and if both exposed and nonexposed populations have the same amount of error, unbiased (l ). If the measurement error is unbiased, the study may be weakened but not invalidated. However, if there is differential misclassification among the exposed and non exposed, or if there is a tendency to over or underestimate the prevalence, inappropriate conclusions could be reached
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