519 research outputs found
Magnetic interaction of Co ions near the {10\bar{1}0} ZnO surface
Co-doped ZnO is the prototypical dilute magnetic oxide showing many of the
characteristics of ferromagnetism. The microscopic origin of the long range
order however remains elusive, since the conventional mechanisms for the
magnetic interaction, such as super-exchange and double exchange, fail either
at the fundamental or at a quantitative level. Intriguingly, there is a growing
evidence that defects both in point-like or extended form play a fundamental
role in driving the magnetic order. Here we explore one of such possibilities
by performing {\it ab initio} density functional theory calculations for the
magnetic interaction of Co ions at or near a ZnO \{100\} surface. We
find that extended surface states can hybridize with the -levels of Co and
efficiently mediate the magnetic order, although such a mechanism is effective
only for ions placed in the first few atomic planes near the surface. We also
find that the magnetic anisotropy changes at the surface from an hard-axis
easy-plane to an easy axis, with an associated increase of its magnitude. We
then conclude that clusters with high densities of surfacial Co ions may
display blocking temperatures much higher than in the bulk
Eliciting Informative Priors by Modelling Expert Decision Making
This article introduces a new method for eliciting prior distributions from
experts. The method models an expert decision-making process to infer a prior
probability distribution for a rare event . More specifically, assuming
there exists a decision-making process closely related to which forms a
decision , where a history of decisions have been collected. By modelling
the data observed to make the historic decisions, using a Bayesian model, an
analyst can infer a distribution for the parameters of the random variable .
This distribution can be used to approximate the prior distribution for the
parameters of the random variable for event . This method is novel in the
field of prior elicitation and has the potential of improving upon current
methods by using real-life decision-making processes, that can carry real-life
consequences, and, because it does not require an expert to have statistical
knowledge. Future decision making can be improved upon using this method, as it
highlights variables that are impacting the decision making process. An
application for eliciting a prior distribution of recidivism, for an
individual, is used to explain this method further
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Genomics, Computational Biology and Drug Discovery for Mycobacterial Infections: Fighting the Emergence of Resistance
Tuberculosis (TB) and leprosy are mycobacterial infections caused by Mycobacterium tuberculosis and Mycobacterium leprae respectively. These diseases continue to be endemic in developing countries where the cost of new medicines presents major challenges. The situation is further exacerbated by the emergence of resistance to many front-line antibiotics. A priority now is to design new antimycobacterials that are not only effective in combatting the diseases but are also less likely to give rise to resistance. In both these respects understanding the structure of drug targets in M. tuberculosis and M. leprae is crucial. In this review we describe structure-guided approaches to understanding the impacts of mutations that give rise to antimycobacterial resistance and the use of this information in the design of new medicines
Squeezed States and Affleck Dine Baryogenesis
Quantum fluctuations in the post inflationary Affleck-Dine baryogenesis model
are studied. The squeezed states formalism is used to give evolution equations
for the particle and anti-particle modes in the early universe. The role of
expansion and parametric amplification of the quantum fluctuations on the
baryon asymmetry produced is investigated.Comment: 8 pages 9 figure
NATURAL PRODUCTS AS AN IMPORTANT LEADS FOR DISCOVERY OF NEW ANTITUBERCULAR AGENTS: A REVIEW
There is a very much need for a discovery of new molecules a potent molecule that can cure tuberculosis and prevent the recurrence. A multidisciplinary approach is required to procure a potent bioactive compound and this includes expertise in the fields of ethnobotany, ethnopharmacology and Phytochemistry. The present communication acts as a bioprospecting source for the drug discovery against tuberculosis, including several anti tubercular agents which is used by used by tribal people and prescribed by THPS which showed a good inhibition rate. Therefore, this review strives to describe the literature on the traditional plants/potent molecules those have been proved to have antimicrobial activity and to provide essential discussion and accelerate the research.Â
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