3,740 research outputs found
Prevalence and factors of sibling-recurrent dental treatment under general anesthesia
Objective/Aims: Assess the prevalence of sibling recurrent dental general anesthesia (DGA) at VCU Pediatric Dentistry. Assess factors that contribute to sibling recurrent dental general anesthesia. Methods: The guardian of patients with siblings were provided a questionnaire to assess the prevalence and factors associated with recurrent DGA. Results: A total of 40 families with a child presenting for GA and at least one sibling were included in the study. Of these, 45% had sibling-recurrent GA treatment (20% in one sibling; 25% in 2 or more siblings). Additionally, 13% of the children currently presenting for GA had already been treated under GA, and 15% of the siblings previously treated with GA had recurrent caries after GA. Conclusion: Sibling-recurrent general anesthesia is high at VCU Pediatric Dentistry Clinic. This increased prevalence could be due to parental acceptance and positive experiences with DGA. Dental providers should be pro-active with prevention methods
Adaptive colour change and background choice behaviour in peppered moth caterpillars is mediated by extraocular photoreception
Light sensing by tissues distinct from the eye occurs in diverse animal groups, enabling circadian control and phototactic behaviour. Extraocular photoreceptors may also facilitate rapid colour change in cephalopods and lizards, but little is known about the sensory system that mediates slow colour change in arthropods. We previously reported that slow colour change in twig-mimicking caterpillars of the peppered moth (Biston betularia) is a response to achromatic and chromatic visual cues. Here we show that the perception of these cues, and the resulting phenotypic responses, does not require ocular vision. Caterpillars with completely obscured ocelli remained capable of enhancing their crypsis by changing colour and choosing to rest on colour-matching twigs. A suite of visual genes, expressed across the larval integument, likely plays a key role in the mechanism. To our knowledge, this is the first evidence that extraocular colour sensing can mediate pigment-based colour change and behaviour in an arthropod
On Multilingual Training of Neural Dependency Parsers
We show that a recently proposed neural dependency parser can be improved by
joint training on multiple languages from the same family. The parser is
implemented as a deep neural network whose only input is orthographic
representations of words. In order to successfully parse, the network has to
discover how linguistically relevant concepts can be inferred from word
spellings. We analyze the representations of characters and words that are
learned by the network to establish which properties of languages were
accounted for. In particular we show that the parser has approximately learned
to associate Latin characters with their Cyrillic counterparts and that it can
group Polish and Russian words that have a similar grammatical function.
Finally, we evaluate the parser on selected languages from the Universal
Dependencies dataset and show that it is competitive with other recently
proposed state-of-the art methods, while having a simple structure.Comment: preprint accepted into the TSD201
Node-balancing by edge-increments
Suppose you are given a graph with a weight assignment
and that your objective is to modify using legal
steps such that all vertices will have the same weight, where in each legal
step you are allowed to choose an edge and increment the weights of its end
points by .
In this paper we study several variants of this problem for graphs and
hypergraphs. On the combinatorial side we show connections with fundamental
results from matching theory such as Hall's Theorem and Tutte's Theorem. On the
algorithmic side we study the computational complexity of associated decision
problems.
Our main results are a characterization of the graphs for which any initial
assignment can be balanced by edge-increments and a strongly polynomial-time
algorithm that computes a balancing sequence of increments if one exists.Comment: 10 page
Cylindrical gravitational waves in expanding universes: Models for waves from compact sources
New boundary conditions are imposed on the familiar cylindrical gravitational
wave vacuum spacetimes. The new spacetime family represents cylindrical waves
in a flat expanding (Kasner) universe. Space sections are flat and nonconical
where the waves have not reached and wave amplitudes fall off more rapidly than
they do in Einstein-Rosen solutions, permitting a more regular null inifinity.Comment: Minor corrections to references. A note added in proo
Virtual Resonant States in Two-Photon Decay Processes: Lower-Order Terms, Subtractions, and Physical Interpretations
We investigate the two-photon decay rate of a highly excited atomic state
which can decay to bound states of lower energy via cascade processes. We show
that a naive treatment of the process, based on the introduction of
phenomenological decay rates for the intermediate, resonant states, leads to
lower-order terms which need to be subtracted in order to obtain the coherent
two-photon correction to the decay rate. The sum of the lower-order terms is
exactly equal to the one-photon decay rate of the initial state, provided the
naive two-photon decay rates are summed over all available two-photon channels.
A quantum electrodynamics (QED) treatment of the problem leads to an
"automatic" subtraction of the lower-order terms.Comment: 8 pages, RevTe
Momentum distributions and spectroscopic factors of doubly-closed shell nuclei in correlated basis function theory
The momentum distributions, natural orbits, spectroscopic factors and
quasi-hole
wave functions of the C12, O16, Ca40, Ca48, and Pb208 doubly closed shell
nuclei, have been calculated in the framework of the Correlated Basis Function
theory, by using the Fermi hypernetted chain resummation techniques. The
calculations have been done by using the realistic Argonne v8' nucleon-nucleon
potential, together with the Urbana IX three-body interaction. Operator
dependent correlations, which consider channels up to the tensor ones, have
been
used. We found noticeable effects produced by the correlations. For high
momentum values, the momentum distributions show large enhancements with
respect to the independent particle model results. Natural orbits occupation
numbers are depleted by about the 10\% with respect to the independent particle
model values. The effects of the correlations on the spectroscopic factors are
larger on the more deeply bound states.Comment: Modified version of the previous paper (there are new figures). The
paper has been accepted for publication in Physical Review
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