89 research outputs found
Infections are a very dangerous affair: Enterobiasis and death
Background: Enterobiasis or oxyuriasis from Enterobius vermicularis is an infection usually localized in the large bowel and cecum. Generally, the symptoms are characterized by anal itching, and intestinal or nervous disorders. Rarely, it is responsible for death. Methods: A forensic autopsy of a 52-year-old white male inmate who died 5 days after hospitalization was performed. Histological and toxicological analyses were also performed. Results: The death occurred by localization of Enterobius vermicularis in the duodenum and in the proximal ileum, with intestinal haemorrhage, inflammation, and peritonitis documented by histological examination. Conclusion: This is a common infectious disease, and can rarely occur with a fatal outcome, even in advanced populations. The lack of knowledge related to the rarity of death from enterobiasis disease can determine a dangerous concern
High intensity tapping regime in a frustrated lattice gas model of granular compaction
In the frame of a well established lattice gas model for granular compaction,
we investigate the high intensity tapping regime where a pile expands
significantly during external excitation. We find that this model shows the
same general trends as more sophisticated models based on molecular dynamic
type simulations. In particular, a minimum in packing fraction as a function of
tapping strength is observed in the reversible branch of an annealed tapping
protocol.Comment: 5 pages, 4 figure
Glassy states in lattice models with many coexisting crystalline phases
We study the emergence of glassy states after a sudden cooling in lattice
models with short range interactions and without any a priori quenched
disorder. The glassy state emerges whenever the equilibrium model possesses a
sufficient number of coexisting crystalline phases at low temperatures,
provided the thermodynamic limit be taken before the infinite time limit. This
result is obtained through simulations of the time relaxation of the standard
Potts model and some exclusion models equipped with a local stochastic dynamics
on a square lattice.Comment: 12 pages, 4 figure
A hard-sphere model on generalized Bethe lattices: Statics
We analyze the phase diagram of a model of hard spheres of chemical radius
one, which is defined over a generalized Bethe lattice containing short loops.
We find a liquid, two different crystalline, a glassy and an unusual
crystalline glassy phase. Special attention is also paid to the close-packing
limit in the glassy phase. All analytical results are cross-checked by
numerical Monte-Carlo simulations.Comment: 24 pages, revised versio
Approximation schemes for the dynamics of diluted spin models: the Ising ferromagnet on a Bethe lattice
We discuss analytical approximation schemes for the dynamics of diluted spin
models. The original dynamics of the complete set of degrees of freedom is
replaced by a hierarchy of equations including an increasing number of global
observables, which can be closed approximately at different levels of the
hierarchy. We illustrate this method on the simple example of the Ising
ferromagnet on a Bethe lattice, investigating the first three possible
closures, which are all exact in the long time limit, and which yield more and
more accurate predictions for the finite-time behavior. We also investigate the
critical region around the phase transition, and the behavior of two-time
correlation functions. We finally underline the close relationship between this
approach and the dynamical replica theory under the assumption of replica
symmetry.Comment: 21 pages, 5 figure
Universal features of correlated bursty behaviour
Inhomogeneous temporal processes, like those appearing in human
communications, neuron spike trains, and seismic signals, consist of
high-activity bursty intervals alternating with long low-activity periods. In
recent studies such bursty behavior has been characterized by a fat-tailed
inter-event time distribution, while temporal correlations were measured by the
autocorrelation function. However, these characteristic functions are not
capable to fully characterize temporally correlated heterogenous behavior. Here
we show that the distribution of the number of events in a bursty period serves
as a good indicator of the dependencies, leading to the universal observation
of power-law distribution in a broad class of phenomena. We find that the
correlations in these quite different systems can be commonly interpreted by
memory effects and described by a simple phenomenological model, which displays
temporal behavior qualitatively similar to that in real systems
A List Referring Monte Carlo Method for Lattice Glass Models
We present an effcient Monte-Carlo method for lattice glass models which are
characterized by hard constraint conditions. The basic idea of the method is
similar to that of the -fold way method. By using a list of sites into which
we can insert a particle, we avoid trying a useless transition which is
forbidden by the constraint conditions. We applied the present method to a
lattice glass model proposed by Biroli and M{\'e}zard. We first evaluated the
efficiency of the method through measurements of the autocorrelation function
of particle configurations. As a result, we found that the efficiency is much
higher than that of the standard Monte-Carlo method. We also compared the
efficiency of the present method with that of the -fold way method in
detail. We next examined how the efficiency of extended ensemble methods such
as the replica exchange method and the Wang-Landau method is inflnuenced by the
choice of the local update method. The results show that the efficiency is
considerably improved by the use of efficient local update methods. For
example, when the number of sites is 1024, the ergodic time
of the replica exchange method in the grand-canonical ensemble,
which is the average round-trip time of a replica in chemical-potential space,
with the present local update method is more than times shorter than
that with the standard local update method. This result shows that the
efficient local update method is quite important to make extended ensemble
methods more effective.Comment: 16 pages, 21 figures; 1 subsection, 1 appendix, and 5 figures are
added, abstract is changed, 1 figure is remove
The epidemiology of Varicella Zoster Virus infection in Italy
<p>Abstract</p> <p>Background</p> <p>The epidemiological importance of varicella and zoster and the availability of an efficacious and safe vaccine have led to an important international debate regarding the suitability of mass vaccination. The objective of the study was to describe the epidemiology of varicella and zoster in Italy and to determine whether there have been changes with respect to observations provided by an analogous study conducted 8 years ago, in order to define the most appropriate vaccination strategy.</p> <p>Methods</p> <p>A number of data sources were evaluated, a cross-sectional population-based seroprevalence study was conducted on samples collected in 2004, and the results were compared with data obtained in 1996.</p> <p>Results</p> <p>The data from active and passive surveillance systems confirm that varicella is a widespread infectious disease which mainly affects children. VZV seroprevalence did not substantially differ from that found in the previous study. The sero-epidemiological profile in Italy is different from that in other European countries. In particular, the percentage of susceptible adolescents is at least nearly twice as high as in other European countries and in the age group 20–39 yrs, approximately 9% of individuals are susceptible to VZV.</p> <p>Conclusion</p> <p>The results of this study can contribute to evaluating the options for varicella vaccination. It is possible that in a few years, in all Italian Regions, there will exist the conditions necessary for implementing a mass vaccination campaign and that the large-scale availability of MMRV tetravalent vaccines will facilitate mass vaccination.</p
Dynamic model of elastoplastic normal collision of spherical particles under nonlocal plasticity
The problem of normal collision of a spherical particle with a half-space is considered with allowance for nonlocal plastic deformation in the case where the strength limit depends on the contact radius, as well as for the strengthening effect in the deformed material. The dimensionless coefficient of normal velocity restitution has been calculated numerically as a function of the initial velocity of the spherical particle. The obtained data coincide well with experimental results available in the literature
Effect of Interaction on the Formation of Memories in Paste
A densely packed colloidal suspension with plasticity, called paste, is known
to remember directions of vibration and flow. These memories in paste can be
visualized by the morphology of desiccation crack patterns. Here, we find that
paste made of charged colloidal particles cannot remember flow direction. If we
add sodium chloride into such paste to screen the Coulombic repulsive
interaction between particles, the paste comes to remember flow direction. That
is, one drop of salt water changes memory effect in the paste and thereby we
can tune the morphology of desiccation crack patterns more precisely.Comment: 10 pages, 11 figures, Title change
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