121 research outputs found
Fermi resonance in Ne, Ar and Kr-matrix infrared spectra of 5-bromouracil
Low-temperature matrix isolation Fourier-transform infrared spectroscopy and quantum-chemical calcula-tions with DFT/B3LYP and MP2 methods were used for investigation of isolated 5-bromouracil (BrU) mole-cules. Only one tautomeric form of BrU was dominated in the low-temperature Ne, Ar, and Kr matrices. It was revealed that population of minor hydroxy-tautomers did not exceed 0.2%. Appearance of additional absorption bands in the region of stretching vibrations CO (about 1710 cm⁻¹) as well as of deformation ones (1297, 1093, 901 cm⁻¹) was explained by Fermi resonance. In Ne matrices the peak intensities of absorption bands assigned to the out-of-plane vibrations of the ring and exocyclic atoms were decreased sharply. For the first time, least square method with the using of polynomial was proposed for the corrective scaling of calculated frequencies of vibrations. It is shown that the correction of calculated frequencies with the polynomial of degree two permits to decrease the root-mean-square discrepancy between the calculated and experimental ones to 4–5 cm⁻¹ in the re-gion of 1500–500 cm⁻¹. The same polynomial may be applied for the correction of spectra of molecules with a similar structure
Stability of Negative Image Equilibria in Spike-Timing Dependent Plasticity
We investigate the stability of negative image equilibria in mean synaptic
weight dynamics governed by spike-timing dependent plasticity (STDP). The
neural architecture of the model is based on the electrosensory lateral line
lobe (ELL) of mormyrid electric fish, which forms a negative image of the
reafferent signal from the fish's own electric discharge to optimize detection
of external electric fields. We derive a necessary and sufficient condition for
stability, for arbitrary postsynaptic potential functions and arbitrary
learning rules. We then apply the general result to several examples of
biological interest.Comment: 13 pages, revtex4; uses packages: graphicx, subfigure; 9 figures, 16
subfigure
Linear stability analysis of retrieval state in associative memory neural networks of spiking neurons
We study associative memory neural networks of the Hodgkin-Huxley type of
spiking neurons in which multiple periodic spatio-temporal patterns of spike
timing are memorized as limit-cycle-type attractors. In encoding the
spatio-temporal patterns, we assume the spike-timing-dependent synaptic
plasticity with the asymmetric time window. Analysis for periodic solution of
retrieval state reveals that if the area of the negative part of the time
window is equivalent to the positive part, then crosstalk among encoded
patterns vanishes. Phase transition due to the loss of the stability of
periodic solution is observed when we assume fast alpha-function for direct
interaction among neurons. In order to evaluate the critical point of this
phase transition, we employ Floquet theory in which the stability problem of
the infinite number of spiking neurons interacting with alpha-function is
reduced into the eigenvalue problem with the finite size of matrix. Numerical
integration of the single-body dynamics yields the explicit value of the
matrix, which enables us to determine the critical point of the phase
transition with a high degree of precision.Comment: Accepted for publication in Phys. Rev.
Assessing the feasibility of interrupting the transmission of soil-transmitted helminths through mass drug administration: The DeWorm3 cluster randomized trial protocol
DeWorm3 collectionThe file attached is the Published/publisher’s pdf version of the article.© 2018 Ásbjörnsdóttir et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
One health, une seule santé
One Health, « Une seule santé », est une stratégie mondiale visant à développer les collaborations interdisciplinaires pour la santé humaine, animale et environnementale. Elle promeut une approche intégrée, systémique et unifiée de la santé aux échelles locale, nationale et mondiale, afin de mieux affronter les maladies émergentes à risque pandémique, mais aussi s'adapter aux impacts environnementaux présents et futurs. Bien que ce mouvement s’étende, la littérature en français reste rare. Traduit de l’anglais, coordonné par d’éminents épidémiologistes et s'appuyant sur un large panel d' approches scientifiques rarement réunies autour de la santé, cet ouvrage retrace les origines du concept et présente un contenu pratique sur les outils méthodologiques, la collecte de données, les techniques de surveillance et les plans d’étude. Il combine recherche et pratique en un seul volume et constitue un ouvrage de référence unique pour la santé mondiale
Genetic heterogeneity of day blindness in Alaskan Malamutes
Day blindness is a progressive and specific degeneration of cone photoreceptors in the retina of young dogs. This disorder has been associated with a breed-specific non-synonymous substitution in exon 6 of the cyclic nucleotide gated channel beta 3 (CNGB3) gene in German Shorthaired Pointer dogs and a genomic deletion removing the entire gene in Alaskan Malamute dogs from the USA. To further investigate this disorder, we characterized CNGB3 in a three-generation pedigree of Alaskan Malamute dogs from Australia segregating for day blindness. Fifteen of the dogs showed clinical signs of day blindness. Four of these were definitively diagnosed by standardized electroretinography. Polymerase chain reaction amplification of exon 6 of CNGB3 was attempted, and as expected, amplification was successful in the 18 unaffected or carrier dogs. However, a non-mutated exon 6 was also amplified and sequenced in six of the 15 affected dogs. On sequencing each exon and exon/intron boundary in two such affected individuals and two unaffected individuals, three exonic substitutions and 12 intronic changes were noted. These sequence variations in affected individuals were also present in one or both unaffected dogs and so appear to have no obvious effect on the protein's function. Hence, day blindness shows genetic heterogeneity within the Alaskan Malamute population of Australia, a result that is somewhat unexpected given the relatively small effective population size of this breed
- …