671 research outputs found

    Stationary States in Infinite Volume with Non-zero Current

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    We study the Ginzburg\u2013Landau stochastic models in infinite domains with some special geometry and prove that without the help of external forces there are stationary measures with non-zero current in three or more dimensions

    Nonconventional averages along arithmetic progressions and lattice spin systems

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    We study the so-called nonconventional averages in the context of lattice spin systems, or equivalently random colourings of the integers. For i.i.d. colourings, we prove a large deviation principle for the number of monochromatic arithmetic progressions of size two in the box [1,N]N[1,N]\cap \N, as NN\to\infty, with an explicit rate function related to the one-dimensional Ising model. For more general colourings, we prove some bounds for the number of monochromatic arithmetic progressions of arbitrary size, as well as for the maximal progression inside the box [1,N]N[1,N]\cap \N. Finally, we relate nonconventional sums along arithmetic progressions of size greater than two to statistical mechanics models in dimension larger than one.Comment: 18 pages, 3 figures. A new section was added on arithmetic progressions of length larger than 2 and statistical mechanics models on Z^d, d>1. To appear in Indagationes Mathematicae (2012

    Super-hydrodynamic limit in interacting particle systems

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    This paper is a follow-up of the work initiated in [3], where it has been investigated the hydrodynamic limit of symmetric independent random walkers with birth at the origin and death at the rightmost occupied site. Here we obtain two further results: first we characterize the stationary states on the hydrodynamic time scale and show that they are given by a family of linear macroscopic profiles whose parameters are determined by the current reservoirs and the system mass. Then we prove the existence of a super-hyrdrodynamic time scale, beyond the hydrodynamic one. On this larger time scale the system mass fluctuates and correspondingly the macroscopic profile of the system randomly moves within the family of linear profiles, with the randomness of a Brownian motion.Comment: 22 page

    Duality relations for the ASEP conditioned on a low current

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    We consider the asymmetric simple exclusion process (ASEP) on a finite lattice with periodic boundary conditions, conditioned to carry an atypically low current. For an infinite discrete set of currents, parametrized by the driving strength sKs_K, K1K \geq 1, we prove duality relations which arise from the quantum algebra Uq[gl(2)]U_q[\mathfrak{gl}(2)] symmetry of the generator of the process with reflecting boundary conditions. Using these duality relations we prove on microscopic level a travelling-wave property of the conditioned process for a family of shock-antishock measures for N>KN>K particles: If the initial measure is a member of this family with KK microscopic shocks at positions (x1,,xK)(x_1,\dots,x_K), then the measure at any time t>0t>0 of the process with driving strength sKs_K is a convex combination of such measures with shocks at positions (y1,,yK)(y_1,\dots,y_K). which can be expressed in terms of KK-particle transition probabilities of the conditioned ASEP with driving strength sNs_N.Comment: 26 page

    Oral and craniofacial manifestations of Ellis-Van Creveld syndrome: A systematic review

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    Aim A systematic literature review on oral and craniofacial manifestations of Ellis-Van Creveld syndrome was performed. Methods From 2 databases were selected 74 articles using as key words "Ellis-Van Creveld" AND "Oral" OR "Craniofacial" OR "Dental" OR "Malocclusion". Prisma protocol was used to create an eligible list for the screening. Data were collected in a table to compare the clinical aspects found. Results From the first research emerged 350 articles, and only 72 of them were selected. Conclusion Through this analysis oral and cranio-facial manifestations of Ellis-Van Creveld syndrome were pointed out. Management of Ellis-Van Creveld syndrome requires a multidisciplinary approach involving different clinicians; dentists play an important role in early diagnosis and treatment of the patients

    Oral health status among migrants from middle-and low-income countries to europe: A systematic review

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    Introduction. Economic inequality, political instability and globalization have contributed to the constant growth of the migration phenomenon in recent years. In particular, a total of 4.2 million people migrated to Europe during 2019 and most of them settled in Germany, France and Italy. Objectives. The objective of this study was to conduct a systematic review of studies analyzing the oral health condition among migrants from middle-and low-income countries to Europe and assessing the eventual association between their sociodemographic and socioeconomic characteristics and oral health status. Materials and Methods. A systematic review was conducted in PubMed, Cochrane Library, Scopus and Science Direct databases. After titles, abstracts and full-text exami-nation, only 27 articles were selected on the basis of inclusion criteria and consequently included for quality assessments and data extraction. Results. Most of the studies reported a higher prevalence of caries experience, a poorer periodontal health and more difficulties in accessing dentalcare services among migrant groups compared with the non-migrant population. Inequalities were mostly associated with ethnic background, economic condition and social grade. Conclusion. Our review demonstrates the lack of dental health among migrants, underlining that their cultural beliefs and their social and economic living conditions could influence their oral health

    Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

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    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to Eo 20 MeV if only polyethylene spheres are used, but can be extended to hundreds of MeV by including metal-loaded spheres (extended range BSS, indicated with ERBSS). With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, an ERBSS experiment was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN—LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points wer

    Expansion of the alveolar bone crest with ultrasonic surgery device: clinical study in mandible.

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    The purpose of this paper was to document the application to the split-crest mandibular procedure in two stage in order to avoid cortical resorption due to periosteal detachment in buccal cortical bone of the alveolar crest. Twenty-two healthy patients with non-contributory past medical history (14 women and 8 men, all non-smokers, mean age 59 years, range 54–65 years) were included in this study. After buccal mucoperiosteal flap was followed by a sagittal corticotomy in the coronal area of the alveolar crest and a second sagittal corticotomy, but in a lower (basal) position and two vertical corticotomies in the buccal wall, using a ultrasonic surgery device (Surgysonic, Esacrom, Imola Italy). Adequate crest expansion was achieved without compromising cortical vascularisation by utilising a combination of scalpel, thin chisels and threaded osteotomes (Bone System, Milano, Italy). Postoperative results were assessed by panoramic and periapical radiographs. Ossification of the osteotomy lines was evident and could be observed as sites with increasing radiopacity on panoramic and periapical radiographs 3 months after implants insertion. No dehiscence of the mucosa was observed. No patient suffered from hypoaesthesia. The mean horizontal bone increase in coronal area was 5±3 mm. Mandibular ridge expansion using a split-crest technique that included grafting the implant sites with a ultrasonic surgery device is a viable therapeutic alternative for implant placement in this patient population

    Stochastic Duality and Orthogonal Polynomials

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    For a series of Markov processes we prove stochastic duality relations with duality functions given by orthogonal polynomials. This means that expectations with respect to the original process (which evolves the variable of the orthogonal polynomial) can be studied via expectations with respect to the dual process (which evolves the index of the polynomial). The set of processes include interacting particle systems, such as the exclusion process, the inclusion process and independent random walkers, as well as interacting diffusions and redistribution models of Kipnis–Marchioro–Presutti type. Duality functions are given in terms of classical orthogonal polynomials, both of discrete and continuous variable, and the measure in the orthogonality relation coincides with the process stationary measure
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