1,909 research outputs found
Temporal and dimensional effects in evolutionary graph theory
The spread in time of a mutation through a population is studied analytically
and computationally in fully-connected networks and on spatial lattices. The
time, t_*, for a favourable mutation to dominate scales with population size N
as N^{(D+1)/D} in D-dimensional hypercubic lattices and as N ln N in
fully-connected graphs. It is shown that the surface of the interface between
mutants and non-mutants is crucial in predicting the dynamics of the system.
Network topology has a significant effect on the equilibrium fitness of a
simple population model incorporating multiple mutations and sexual
reproduction. Includes supplementary information.Comment: 6 pages, 4 figures Replaced after final round of peer revie
On -functions with bounded spectrum
We consider the class of functions in ,
whose Fourier transform has bounded support. We obtain a description of
continuous maps such that
for every function .
Only injective affine maps have this property
Corneoscleral laceration and ocular burns caused by electronic cigarette explosions
PURPOSE: To report cases of acute globe rupture and bilateral corneal burns from electronic cigarette (EC) explosions. METHODS: Case series. RESULTS: We describe a series of patients with corneal injury caused by EC explosions. Both patients suffered bilateral corneal burns and decreased visual acuity, and one patient sustained a unilateral corneoscleral laceration with prolapsed iris tissue and hyphema. A review of the scientific literature revealed no prior reported cases of ocular injury secondary to EC explosions; however, multiple media and government agency articles describe fires and explosions involving ECs, including at least 4 with ocular injuries. CONCLUSIONS: Given these cases and the number of recent media reports, ECs pose a significant public health risk. Users should be warned regarding the possibility of severe injury, including sight-threatening ocular injuries ranging from corneal burns to full-thickness corneoscleral laceration
A systematic review with meta-analysis of studies comparing response to experimentally-evoked pain between obese and non-obese individuals
© 2018 Astita et al. Background: The relationship between obesity and pain remains unclear. The aim of this systematic review was to determine whether response to experimentally-evoked pain differed between obese and non-obese individuals. Studies that compared responses to experimentally-evoked pain between obese and non-obese human participants post-puberty (i.e. >16 years) were sought. Eligible studies published between January 1950 and May 2017 were identified by searching OVID, MEDLINE, EMBASE and Science Direct. Explanation: Methodological quality of included studies was assessed using the ‘QualSyst’ questionnaire. Of 1106 references identified only nine studies (683 participants) were eligible for review. Pressure pain was assessed in five studies and electrical pain in three studies. Two studies investigated thermal pain. Obesity was categorized according to body mass index (BMI) or as weight as a percentage of ideal body weight. Six of the nine included studies were of low methodological quality. There was a lack of extractable data to pool for meta-analysis of studies using thermal or electrical pain. A forest plot of data extracted from four studies on pressure pain threshold found no differences between obese and non-obese groups (overall effect size was Z=0.57, p=0.57). Conclusion: Small sample size was the main limitation in all studies. Participants with obesity were more sensitive to mechanical noxious stimuli than non-obese participants in three of five studies. However, overall, it was not possible to determine whether there are differences in pain sensitivity response to experimental stimuli between obese and non-obese individuals
Conductance Phases in Aharonov-Bohm Ring Quantum Dots
The regimes of growing phases (for electron numbers N~0-8) that pass into
regions of self-returning phases (for N>8), found recently in quantum dot
conductances by the Weizmann group are accounted for by an elementary Green
function formalism, appropriate to an equi-spaced ladder structure (with at
least three rungs) of electronic levels in the quantum dot. The key features of
the theory are physically a dissipation rate that increases linearly with the
level number (and tentatively linked to coupling to longitudinal optical
phonons) and a set of Fano-like meta-stable levels, which disturb the
unitarity, and mathematically the change over of the position of the complex
transmission amplitude-zeros from the upper-half in the complex gap-voltage
plane to the lower half of that plane. The two regimes are identified with
(respectively) the Blaschke-term and the Kramers-Kronig integral term in the
theory of complex variables.Comment: 20 pages, 4 figure
The Late Time Behavior of False Vacuum Decay: Possible Implications for Cosmology and Metastable Inflating States
We describe here how the late time behavior of the decaying states, which is
predicted to deviate from an exponential form, while normally of insignificant
consequence, may have important cosmological implications in the case of false
vacuum decay. It may increase the likelihood of eternal inflation, and may help
explain the likelihood of observing a small vacuum energy at late times, as
well as arguing against decay into a large negative energy (anti-de Sitter
space), vacuum state as has been motivated by some string theory
considerations. Several interesting open questions are raised, including
whether observing the cosmological configuration of a metastable universe can
constrain its inferred lifetime.Comment: 4 pages, submitted to PRL, one reference changed, and changes to
abstract and concluding sentences to stem possible confusions regarding
observation and metastabilit
The complete mitochondrial genome of a parasite at the animal-fungal boundary
Background: Sphaerothecum destruens is an obligate intracellular fish parasite which has been identified as a serious threat to freshwater fishes. Taxonomically, S. destruens belongs to the order Dermocystida within the class Ichthyosporea (formerly referred to as Mesomycetozoea), which sits at the animal-fungal boundary. Mitochondrial DNA (mtDNA) sequences can be valuable genetic markers for species detection and are increasingly used in environmental DNA (eDNA) based species detection. Furthermore, mtDNA sequences can be used in epidemiological studies by informing detection, strain identification and geographical spread. Methods: We amplified the entire mitochondrial (mt) genome of S. destruens in two overlapping long fragments using primers designed based on the cox1, cob and nad5 partial sequences. The mt-genome architecture of S. destruens was then compared to close relatives to gain insights into its evolution. Results: The complete mt-genome of Sphaerothecum destruens is 23,939 bp in length and consists of 47 genes including 21 protein-coding genes, 2 rRNA, 22 tRNA and two unidentified open reading frames. The mitochondrial genome of S. destruens is intronless and compact with a few intergenic regions and includes genes that are often missing from animal and fungal mt-genomes, such as, the four ribosomal proteins (small subunit rps13 and 14; large subunit rpl2 and 16), tatC (twin-arginine translocase component C), and ccmC and ccmF cytochrome c maturation protein ccmC and heme lyase). Conclusions: We present the first mt-genome of S. destruens which also represents the first mt-genome for the order Dermocystida. The availability of the mt-genome can assist the detection of S. destruens and closely related parasites in eukaryotic diversity surveys using eDNA and assist epidemiological studies by improving molecular detection and tracking the parasite’s spread. Furthermore, as the only representative of the order Dermocystida, its mt-genome can be used in the study of mitochondrial evolution of the unicellular relatives of animals
The rigged Hilbert space approach to the Lippmann-Schwinger equation. Part II: The analytic continuation of the Lippmann-Schwinger bras and kets
The analytic continuation of the Lippmann-Schwinger bras and kets is obtained
and characterized. It is shown that the natural mathematical setting for the
analytic continuation of the solutions of the Lippmann-Schwinger equation is
the rigged Hilbert space rather than just the Hilbert space. It is also argued
that this analytic continuation entails the imposition of a time asymmetric
boundary condition upon the group time evolution, resulting into a semigroup
time evolution. Physically, the semigroup time evolution is simply a (retarded
or advanced) propagator.Comment: 32 pages, 3 figure
Dynamical percolation on general trees
H\"aggstr\"om, Peres, and Steif (1997) have introduced a dynamical version of
percolation on a graph . When is a tree they derived a necessary and
sufficient condition for percolation to exist at some time . In the case
that is a spherically symmetric tree, H\"aggstr\"om, Peres, and Steif
(1997) derived a necessary and sufficient condition for percolation to exist at
some time in a given target set . The main result of the present paper
is a necessary and sufficient condition for the existence of percolation, at
some time , in the case that the underlying tree is not necessary
spherically symmetric. This answers a question of Yuval Peres (personal
communication). We present also a formula for the Hausdorff dimension of the
set of exceptional times of percolation.Comment: 24 pages; to appear in Probability Theory and Related Field
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