6,611 research outputs found
Inherent structures and non-equilibrium dynamics of 1D constrained kinetic models: a comparison study
e discuss the relevance of the Stillinger and Weber approach to the glass
transition investigating the non-equilibrium behavior of models with
non-trivial dynamics, but with simple equilibrium properties. We consider a
family of 1D constrained kinetic models, which interpolates between the
asymmetric chain introduced by Eisinger and J\"ackle [Z. Phys. {\bf B84}, 115
(1991)] and the symmetric chain introduced by Fredrickson and Andersen [Phys.
Rev. Lett {\bf 53}, 1244 (1984)], and the 1D version of the Backgammon model
[Phys. Rev. Lett. {\bf 75}, 1190 (1995)]. We show that the configurational
entropy obtained from the inherent structures is the same for all models
irrespective of their different microscopic dynamics. We present a detailed
study of the coarsening behavior of these models, including the relation
between fluctuations and response. Our results suggest that any approach to the
glass transition inspired by mean-field ideas and resting on the definition of
a configurational entropy must rely on the absence of any growing
characteristic coarsening pattern.Comment: 32 pages, 28 figures, RevTe
Linear Toric Fibrations
These notes are based on three lectures given at the 2013 CIME/CIRM summer
school. The purpose of this series of lectures is to introduce the notion of a
toric fibration and to give its geometrical and combinatorial
characterizations. Polarized toric varieties which are birationally equivalent
to projective toric bundles are associated to a class of polytopes called
Cayley polytopes. Their geometry and combinatorics have a fruitful interplay
leading to fundamental insight in both directions. These notes will illustrate
geometrical phenomena, in algebraic geometry and neighboring fields, which are
characterized by a Cayley structure. Examples are projective duality of toric
varieties and polyhedral adjunction theory
A Mixed Real and Floating-Point Solver
Reasoning about mixed real and floating-point constraints is essential for developing accurate analysis tools for floating-point pro- grams. This paper presents FPRoCK, a prototype tool for solving mixed real and floating-point formulas. FPRoCK transforms a mixed formula into an equisatisfiable one over the reals. This formula is then solved using an off-the-shelf SMT solver. FPRoCK is also integrated with the PRECiSA static analyzer, which computes a sound estimation of the round-off error of a floating-point program. It is used to detect infeasible computational paths, thereby improving the accuracy of PRECiSA
A 475 years-old founder effect involving IL12RB1: a highly prevalent mutation conferring Mendelian susceptibility to mycobacterial diseases in European descendants
Mutations in IFNGR1, IFNGR2, IL12RB1, IL12B, STAT1 and NEMO result in a common clinical phenotype known as Mendelian Susceptibility to Mycobacterial Diseases (MSMD). Interleukin-12 receptor 01 (IL12R beta 1) deficiency is the most common genetic etiology for MSMD. Known mutations affecting IL12RB1 are recessively inherited and are associated with null response to both IL-12 and IL-23. Mutation IL12RB1 1623_1624delinsTT was originally described in 5 families from European origin (2 from Germany: I from Cyprus, France and Belgium). Interestingly, this same mutation was found in an unexpectedly high prevalence among IL-12R beta 1 deficient patients in Argentina: 5-out-of-6 individuals born to unrelated families carried this particular change. To determine whether mutation 1623_1624delinsTT represents a DNA mutational hotspot or a founder effect, 34 polymorphic markers internal or proximal to IL12RB1 were studied in the Argentinean and the Belgian patients. A common haplotype spanning 1.45-3.51 Mb was shared by all chromosomes carrying mutation 1623_1624delinsTT, and was not detected on 100 control chromosomes. Applying a modified likelihood-based method the age of the most recent common ancestor carrying mutation 1623_1624delinsTT was estimated in 475 years (95% CI, 175-1275), which is the time when the Spaniards initiated the colonization of the Americas. Mutation 1623_1624delinsTT represents the first founder effect described on IL-12R beta 1, the most frequently affected gene in MSMD, and affecting patients with European ancestors. The reason(s) behind the persistency of this mutation across multiple generations, its relative high prevalence, and any potential selective advantage are yet to be established
A phenomenological theory giving the full statistics of the position of fluctuating pulled fronts
We propose a phenomenological description for the effect of a weak noise on
the position of a front described by the Fisher-Kolmogorov-Petrovsky-Piscounov
equation or any other travelling wave equation in the same class. Our scenario
is based on four hypotheses on the relevant mechanism for the diffusion of the
front. Our parameter-free analytical predictions for the velocity of the front,
its diffusion constant and higher cumulants of its position agree with
numerical simulations.Comment: 10 pages, 3 figure
Evaluating diagnosis and treatment of oral and esophageal candidiasis in Ugandan AIDS patients.
A randomized cross-over clinical and endoscopic evaluation of 85 Ugandan patients showed that esophageal candidiasis in AIDS patients with oral candidiasis could be managed without endoscopy and biopsies. Oral lesions, especially when accompanied by esophageal symptoms, were sufficient for diagnosis. Miconazole was more effective than nystatin in treating esophageal candidiasis and could be a valid alternative to more expensive azolic drugs in developing countries
Towards Safe Human-Robot Interaction: evaluating in real-time the severity of possible collisions in industrial scenarios
It is today a common opinion that a more structured and fruitful human-robot cooperation will facilitate industrial robots to be massively used also in SMEs. In order to guarantee a certain level of safety while removing physica
Enhancement of photoacoustic detection of inhomogeneities in polymers
We report a series of experiments on laser pulsed photoacoustic excitationin
turbid polymer samples addressed to evaluate the sound speed in the samples and
the presence of inhomogeneities in the bulk. We describe a system which allows
the direct measurement of the speed of the detected waves by engraving the
surface of the piece under study with a fiduciary pattern of black lines. We
also describe how this pattern helps to enhance the sensitivity for the
detection of an inhomogeneity in the bulk. These two facts are useful for
studies in soft matter systems including, perhaps, biological samples. We have
performed an experimental analysis on Grilon(R) samples in different situations
and we show the limitations of the method.Comment: 8 pages, 7 figure
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