9,113 research outputs found
Monte Carlo algorithms are very effective in finding the largest independent set in sparse random graphs
The effectiveness of stochastic algorithms based on Monte Carlo dynamics in
solving hard optimization problems is mostly unknown. Beyond the basic
statement that at a dynamical phase transition the ergodicity breaks and a
Monte Carlo dynamics cannot sample correctly the probability distribution in
times linear in the system size, there are almost no predictions nor intuitions
on the behavior of this class of stochastic dynamics. The situation is
particularly intricate because, when using a Monte Carlo based algorithm as an
optimization algorithm, one is usually interested in the out of equilibrium
behavior which is very hard to analyse. Here we focus on the use of Parallel
Tempering in the search for the largest independent set in a sparse random
graph, showing that it can find solutions well beyond the dynamical threshold.
Comparison with state-of-the-art message passing algorithms reveals that
parallel tempering is definitely the algorithm performing best, although a
theory explaining its behavior is still lacking.Comment: 14 pages, 12 figure
Work-related allergic rhinitis: a contemporary review of the literature
Adverse health effects have been reported in workers exposed to inhaled allergens. Allergic rhinitis is a heterogeneous disorder that significantly affects daily activity, work productivity, sleep, learning, and quality of life in all generations. Occupational-ly-related hazards which contribute to the development of allergic rhinitis represent an important avoidable cause of morbidity. The occupational exposure to chemicals or biological agents is the cause of high incidences of allergic rhinitis and this risk is high when the organization and preparation are inadequate and there is a lacking or insufficient information, education and communication. The prevalence of work-related rhinitis, which encompasses both occupational rhinitis and work-exacerbated rhinitis, is estimated to be 31-61%. Data on occupational rhinitis itself are scarce. Although work-related asthma and allergies are a huge burden for society, investigation of oc-cupational exposures in early work life using an unexposed reference group is rare. Occupational allergic diseases are likely to worsen or become intractable as a result of continuous exposure to high concentrations of causative antigens, and are socioeco-nomically important diseases with which the patients might sometimes lose jobs due to work interruptions. It is important to adequately assess, communicate and manage risks in occupational chemical exposure settings with the aim to protect workers and the necessity to introduce periodic health examinations programs focusing on workers to monitor health and well-being and improve working conditions and the working environment
The potential role of perceived support for reduction of special education teachers’ burnout
Teacher burnout is conceived as a general concern in special education because of the emotionally demanding work context. This study explored the potential role of perceived support for reduction of burnout in a sample of 276 special education teachers working in lower (n=130) and higher (n=146) secondary schools. Participants completed the Maslach Burnout Inventory - Educators Survey (MBI-ES) and a scale on the perceived collaboration and support from general education teachers. To explore the association between perceived support and each burnout measure considered (emotional exhaustion, depersonalisation, and personal accomplishment), correlation analyses were performed. Then, in order to check the robustness of our empirical findings, multilevel regression models (at teacher-school-administrative area level) were used controlling for several variables (teacher socio-demographic characteristics, teacher training and professional background, inclusive teaching practice and school context). Results suggest the potential role of perceived support in reducing emotional exhaustion and improving personal accomplishment in all the models considered. Instead, the relationship between perceived support and depersonalisation seems to be quite controversial, moreover when adding controls related to teacher’s training and professional background
Economic–financial evaluation and multicriteria analysis of innovative public transport guided systems: an application to “Linea della Musica” in Rome
Trams and innovative public transport systems in historical city centres, are often not considered by public authorities, due to their strong visual impact, (e.g. in proximity of artistic-cultural places), and high project costs. The decision-makers guess that the high initial investment could not be compensated for in subsequent years. For this reason, it is very important to evaluate all the innovative solutions, not only economically, but considering all externalities, positive and negative, in a multi-criteria analysis taking into account public opinions and passengers’ behaviours essential for assessing revenues, and also return of image. On this basis, the results may be impressive: the positive economic impact may be highlighted, and they can have a result better than traditional systems. The subject of the analysis is the innovative system “Tramwave” of Ansaldo STS that combines an investment cost imperceptibly higher than the traditional tram, and a zero visual impact due to the absence of the overhead line due to the uptake of electrical energy from the ground. This system, applied to “Linea della Musica”, a planned tramway line in Rome, through a detailed financial balance of costs and revenues, shows a positive Net Present Value 30–40 years after the initial investment. The current crisis, both culturally and economically, can cause two types of reactions: an indiscriminate cutting of essential public services, or a positive crackdown, that puts ideas in motion, awakens the pride of the common good, and realizes innovations for saving money. The proposed analysis will try to encourage the second reaction
Low In solubility and band offsets in the small- -GaO/(GaIn)O system
Based on first-principles calculations, we show that the maximum reachable
concentration in the (GaIn)O alloy in the low-
regime (i.e. In solubility in -GaO) is around 10%. We then
calculate the band alignment at the (100) interface between -GaO
and (GaIn)O at 12%, the nearest computationally treatable
concentration. The alignment is strongly strain-dependent: it is of type-B
staggered when the alloy is epitaxial on GaO, and type-A straddling in
a free-standing superlattice. Our results suggest a limited range of
applicability of low-In-content GaInO alloys.Comment: 3 pages, 3 figure
One-loop topological expansion for spin glasses in the large connectivity limit
We apply for the first time a new one-loop topological expansion around the
Bethe solution to the spin-glass model with field in the high connectivity
limit, following the methodological scheme proposed in a recent work. The
results are completely equivalent to the well known ones, found by standard
field theoretical expansion around the fully connected model (Bray and Roberts
1980, and following works). However this method has the advantage that the
starting point is the original Hamiltonian of the model, with no need to define
an associated field theory, nor to know the initial values of the couplings,
and the computations have a clear and simple physical meaning. Moreover this
new method can also be applied in the case of zero temperature, when the Bethe
model has a transition in field, contrary to the fully connected model that is
always in the spin glass phase. Sharing with finite dimensional model the
finite connectivity properties, the Bethe lattice is clearly a better starting
point for an expansion with respect to the fully connected model. The present
work is a first step towards the generalization of this new expansion to more
difficult and interesting cases as the zero-temperature limit, where the
expansion could lead to different results with respect to the standard one.Comment: 8 pages, 1 figur
Ensemble renormalization group for disordered systems
We propose and study a renormalization group transformation that can be used
also for models with strong quenched disorder, like spin glasses. The method is
based on a mapping between disorder distributions, chosen such as to keep some
physical properties (e.g., the ratio of correlations averaged over the
ensemble) invariant under the transformation. We validate this ensemble
renormalization group by applying it to the hierarchical model (both the
diluted ferromagnetic version and the spin glass version), finding results in
agreement with Monte Carlo simulations.Comment: 7 pages, 10 figure
Working with parents to support their disabled children’s social and school inclusion. An exploratory counseling study
This article synthesizes the long-lasting counseling process of a family with a child suffering from a chronic illness. The provided intervention model draws on a series of principles from various theoretical approaches, namely systemic, psychodynamic, and resiliency. Family functioning and support is considered a catalytic parameter in assisting children with disabilities to fully develop their potential. This project is based on a family and child-centered integrative counseling model adopting the nonmedical conception of disability. Through the presentation of a case study of a couple who faced a critical situation in the life of their child, this article briefly describes the way the family dynamics were readdressed through this intervention counseling model. In addition, this work attempts to give a picture of the complex and confusing emotional states parents may go through when dealing with physical and psychological health-threatening situations and present guidelines for integrated counseling models. © 2015 Taylor & Francis Group, LL
Les traités d'"économique" aux XVIe et XVIIe siècles : une forme d'institutio nobilis
International audience: Dans cet article, l'auteur analyse des traités d'économique du XVIe et XVIIe siècles pour montrer comment ils entrent parmi les lieux privilégiés pour la codification de la vie more nobiliu
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