2,224 research outputs found
Global risk model for vector-borne transmission of Zika virus reveals the role of El Nino 2015 (vol 114, pg 119, 2016)
Global risk model for vector-borne transmission of Zika virus reveals the role of El Nino 2015
Zika, a mosquito-borne viral disease that emerged in South America in 2015, was declared a Public Health Emergency of International Concern by the WHO in February of 2016. We developed a climate-driven R(0) mathematical model for the transmission risk of Zika virus (ZIKV) that explicitly includes two key mosquito vector species: Aedes aegypti and Aedes albopictus. The model was parameterized and calibrated using the most up to date information from the available literature. It was then driven by observed gridded temperature and rainfall datasets for the period 1950–2015. We find that the transmission risk in South America in 2015 was the highest since 1950. This maximum is related to favoring temperature conditions that caused the simulated biting rates to be largest and mosquito mortality rates and extrinsic incubation periods to be smallest in 2015. This event followed the suspected introduction of ZIKV in Brazil in 2013. The ZIKV outbreak in Latin America has very likely been fueled by the 2015–2016 El Niño climate phenomenon affecting the region. The highest transmission risk globally is in South America and tropical countries where Ae. aegypti is abundant. Transmission risk is strongly seasonal in temperate regions where Ae. albopictus is present, with significant risk of ZIKV transmission in the southeastern states of the United States, in southern China, and to a lesser extent, over southern Europe during the boreal summer season
Quasiperiodic and Lyndon episturmian words
Recently the second two authors characterized quasiperiodic Sturmian words,
proving that a Sturmian word is non-quasiperiodic if and only if it is an
infinite Lyndon word. Here we extend this study to episturmian words (a natural
generalization of Sturmian words) by describing all the quasiperiods of an
episturmian word, which yields a characterization of quasiperiodic episturmian
words in terms of their "directive words". Even further, we establish a
complete characterization of all episturmian words that are Lyndon words. Our
main results show that, unlike the Sturmian case, there is a much wider class
of episturmian words that are non-quasiperiodic, besides those that are
infinite Lyndon words. Our key tools are morphisms and directive words, in
particular "normalized" directive words, which we introduced in an earlier
paper. Also of importance is the use of "return words" to characterize
quasiperiodic episturmian words, since such a method could be useful in other
contexts.Comment: 33 pages; minor change
Law and Neuroscience: Recommendations Submitted to the President\u27s Bioethics Commission
President Obama charged the Presidential Commission for the Study of Bioethical Issues to identify a set of core ethical standards in the neuroscience domain, including the appropriate use of neuroscience in the criminal-justice system. The Commission, in turn, called for comments and recommendations. The MacArthur Foundation Research Network on Law and Neuroscience submitted a consensus statement, published here, containing 16 specific recommendations. These are organized within three main themes: 1) what steps should be taken to enhance the capacity of the criminal justice system to make sound decisions regarding the admissibility and weight of neuroscientific evidence?; 2) to what extent can the capacity of neurotechnologies to aid in the administration of criminal justice be enhanced through research?; and 3) in what additional ways might important ethical issues at the intersection of neuroscience and criminal justice be addressed
Law and Neuroscience: Recommendations Submitted to the President\u27s Bioethics Commission
President Obama charged the Presidential Commission for the Study of Bioethical Issues to identify a set of core ethical standards in the neuroscience domain, including the appropriate use of neuroscience in the criminal-justice system. The Commission, in turn, called for comments and recommendations. The MacArthur Foundation Research Network on Law and Neuroscience submitted a consensus statement, published here, containing 16 specific recommendations. These are organized within three main themes: 1) what steps should be taken to enhance the capacity of the criminal justice system to make sound decisions regarding the admissibility and weight of neuroscientific evidence?; 2) to what extent can the capacity of neurotechnologies to aid in the administration of criminal justice be enhanced through research?; and 3) in what additional ways might important ethical issues at the intersection of neuroscience and criminal justice be addressed
G2i Knowledge Brief: A Knowledge Brief of the MacArthur Foundation Research Network on Law and Neuroscience
Courts are daily confronted with admissibility issues – such as in cases involving neuroscientific testimony – that sometimes involve both the existence of a general phenomenon (i.e., “G”) and the question of whether a particular case represents a specific instance of that general phenomenon (i.e., “i”).
Unfortunately, courts have yet to carefully consider the implications of “G2i” for their admissibility decisions. In some areas, courts limit an expert’s testimony to the general phenomenon. They insist that whether the case at hand is an instance of that phenomenon is exclusively a jury question, and thus not an appropriate subject of expert opinion. In other cases, in contrast, courts hold that expert evidence must be provided on both the group-data issue (i.e., that the phenomenon exists) and what is called the “diagnostic” issue (i.e., that this case is an instance of that phenomenon).
Consequently, the MacArthur Foundation Research Network on Law and Neuroscience has prepared this knowledge brief to help courts manage the G2i divide. Specifically, we recommend that courts first determine whether proffered expert testimony concerns only the existence of the general phenomenon or instead concerns both that and the diagnosis that a particular case represents an instance of that phenomenon. Only after making that determination should the court make its admissibility decision (guided, for instance, by the Daubert factors for admitting scientific evidence)
Quantum chaos in a deformable billiard: Applications to quantum dots
We perform a detailed numerical study of energy-level and wavefunction
statistics of a deformable quantum billiard focusing on properties relevant to
semiconductor quantum dots. We consider the family of Robnik billiards
generated by simple conformal maps of the unit disk; the shape of this family
of billiards may be varied continuously at fixed area by tuning the parameters
of the map. The classical dynamics of these billiards is well-understood and
this allows us to study the quantum properties of subfamilies which span the
transition from integrability to chaos as well as families at approximately
constant degree of chaoticity (Kolmogorov entropy). In the regime of hard chaos
we find that the statistical properties of interest are well-described by
random-matrix theory and completely insensitive to the particular shape of the
dot. However in the nearly-integrable regime non-universal behavior is found.
Specifically, the level-width distribution is well-described by the predicted
distribution both in the presence and absence of magnetic flux when
the system is fully chaotic; however it departs substantially from this
behavior in the mixed regime. The chaotic behavior corroborates the previously
predicted behavior of the peak-height distribution for deformed quantum dots.
We also investigate the energy-level correlation functions which are found to
agree well with the behavior calculated for quasi-zero-dimensional disordered
systems.Comment: 25 pages (revtex 3.0). 16 figures are available by mail or fax upon
request at [email protected]
Spinodal Decomposition in a Binary Polymer Mixture: Dynamic Self Consistent Field Theory and Monte Carlo Simulations
We investigate how the dynamics of a single chain influences the kinetics of
early stage phase separation in a symmetric binary polymer mixture. We consider
quenches from the disordered phase into the region of spinodal instability. On
a mean field level we approach this problem with two methods: a dynamical
extension of the self consistent field theory for Gaussian chains, with the
density variables evolving in time, and the method of the external potential
dynamics where the effective external fields are propagated in time. Different
wave vector dependencies of the kinetic coefficient are taken into account.
These early stages of spinodal decomposition are also studied through Monte
Carlo simulations employing the bond fluctuation model that maps the chains --
in our case with 64 effective segments -- on a coarse grained lattice. The
results obtained through self consistent field calculations and Monte Carlo
simulations can be compared because the time, length, and temperature scales
are mapped onto each other through the diffusion constant, the chain extension,
and the energy of mixing. The quantitative comparison of the relaxation rate of
the global structure factor shows that a kinetic coefficient according to the
Rouse model gives a much better agreement than a local, i.e. wave vector
independent, kinetic factor. Including fluctuations in the self consistent
field calculations leads to a shorter time span of spinodal behaviour and a
reduction of the relaxation rate for smaller wave vectors and prevents the
relaxation rate from becoming negative for larger values of the wave vector.
This is also in agreement with the simulation results.Comment: Phys.Rev.E in prin
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