11,041 research outputs found
Food safety as a public health issue for developing countries
"This brief reviews the incidence and health consequences of biological pathogens in developing countries, as these are the most important food safety risks in those parts of the world, and provides an overview of possible methods of control." from TextFood safety ,food security ,Public health ,
Kondo effect in three-dimensional Dirac and Weyl systems
Magnetic impurities in three-dimensional Dirac and Weyl systems are shown to
exhibit a fascinatingly diverse range of Kondo physics, with distinctive
experimental spectroscopic signatures. When the Fermi level is precisely at the
Dirac point, Dirac semimetals are in fact unlikely candidates for a Kondo
effect due to the pseudogapped density of states. However, the influence of a
nearby quantum critical point leads to the unconventional evolution of Kondo
physics for even tiny deviations in the chemical potential. Separating the
degenerate Dirac nodes produces a Weyl phase: time-reversal symmetry-breaking
precludes Kondo due to an effective impurity magnetic field, but different
Kondo variants are accessible in time-reversal invariant Weyl systems.Comment: 4+ pages, 2 figure
Quantum phase transitions and thermodynamics of the power-law Kondo model
We revisit the physics of a Kondo impurity coupled to a fermionic host with a
diverging power-law density of states near the Fermi level, , with exponent . Using the analytical understanding of
several fixed points, based partially on powerful mappings between models with
bath exponents and , combined with accurate numerical renormalization
group calculations, we determine thermodynamic quantities within the stable
phases, and also near the various quantum phase transitions. Antiferromagnetic
Kondo coupling leads to strong screening with a negative zero-temperature
impurity entropy, while ferromagnetic Kondo coupling can induce a stable
fractional spin moment. We formulate the quantum field theories for all
critical fixed points of the problem, which are fermionic in nature and allow
for a perturbative renormalization-group treatment.Comment: 13 pages, 11 figure
Kondo effect on the surface of 3D topological insulators: Signatures in scanning tunneling spectroscopy
We investigate the scattering off dilute magnetic impurities placed on the
surface of three-dimensional topological insulators. In the low-temperature
limit, the impurity moments are Kondo-screened by the surface-state electrons,
despite their exotic locking of spin and momentum. We determine signatures of
the Kondo effect appearing in quasiparticle interference (QPI) patterns as
recorded by scanning tunneling spectroscopy, taking into account the full
energy dependence of the T matrix as well as the hexagonal warping of the
surface Dirac cones. We identify a universal energy dependence of the QPI
signal at low scanning energies as the fingerprint of Kondo physics, markedly
different from the signal due to non-magnetic or static magnetic impurities.
Finally, we discuss our results in the context of recent experimental data.Comment: 9 pages, 9 figure
Plan Commission Basics for Engineers
Whether you are a plan commission member (city engineer, county surveyor, extension agent) or you have to work with one, this session is designed for you. Learn how “public health, safety, and welfare” plays into not only what you do, but also the decisions the plan commission and other local government bodies make. This session is based on the popular Nitty Gritty for Plan Commission and Board of Zoning Appeals Training Series. We will allow time for Q&A
Navigating the Local Planning Process for Engineers
Engineers and surveyors involved with development or infrastructure must sometimes interact with a local government’s planning department. In Indiana, state law even requires that city plan commissions include the city engineer and that county plan commissions include the county surveyor. This session provides basic information that engineering professionals need to know to successfully navigate the local planning process and public meetings, including state law requirements
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