Self-organized evolution in socio-economic environments

We propose a general scenario to analyze social and economic changes in modern environments. We illustrate the ideas with a model that incorporating the main trends is simple enough to extract analytical results and, at the same time, sufficiently complex to display a rich dynamic behavior. Our study shows that there exists a macroscopic observable that is maximized in a regime where the system is critical, in the sense that the distribution of events follow power-laws. Computer simulations show that, in addition, the system always self-organizes to achieve the optimal performance in the stationary state.Comment: 4 pages RevTeX; needs epsf.sty and rotate.sty; submitted to Phys Rev Let

Perturbation theory for very long-range potentials

Systems with very long-range interactions (that decay at large distances like $U(r)\sim r^{-l}$ with $l\le d$ where $d$ is the space dimensionality) are difficult to study by conventional statistical mechanics perturbation methods. Examples of these systems are gravitational and charged (non-electroneutral). In this work we propose two alternative methodologies to avoid these difficulties and capture some of the properties of the original potential. The first one consists in expressing the original potential in terms of a finite sum of hard-core Yukawa potentials. In the second one, the potential is rewritten as a damped potential, using a damping function with a parameter that controls the range of the interaction. These new potentials, which mimic the original one, can now be treated by conventional statistical mechanics methods.Comment: 25 pages, 11 figure

Optimal network topologies for local search with congestion

The problem of searchability in decentralized complex networks is of great importance in computer science, economy and sociology. We present a formalism that is able to cope simultaneously with the problem of search and the congestion effects that arise when parallel searches are performed, and obtain expressions for the average search cost--written in terms of the search algorithm and the topological properties of the network--both in presence and abscence of congestion. This formalism is used to obtain optimal network structures for a system using a local search algorithm. It is found that only two classes of networks can be optimal: star-like configurations, when the number of parallel searches is small, and homogeneous-isotropic configurations, when the number of parallel searches is large.Comment: 4 pages. Final version accepted in PR

Study of the mechanical behavior of asphalt mixtures using fractional rheology to model their viscoelasticity

This study focuses on the mechanical behavior of asphalt mixtures composed of aggregate particles attached with an asphalt binder. Asphalt mixtures are viscoelastic composite materials widely used in the construction of pavement layers. The modelling of such materials is currently done using the Burgers model. However, this model is limited when explaining some of the viscoelastic phenomena of an asphalt mixture, mainly because the Burgers model was developed for a single material with a dual nature. This work presents a new approach that provides a more appropriate framework for studying asphalt mixtures. The model assumes an aggregate particle enclosed by an asphalt material. Viscoelastic equations were developed using derivatives of fractional order. Then, the creep, recovery, and relaxation phenomena in an asphalt mixture were analyzed using the new model. Unlike the Burgers model, the new model can predict the elastic jump observed at the beginning of the creep modulus. Thus, the new model seems to describe better those practical cases of asphalt mixtures used in the construction of pavement layers. The new model can be used to modify the properties of the binder for designing optimized and more resistant asphalt mixtures

Mesoscopic structure conditions the emergence of cooperation on social networks

We study the evolutionary Prisoner's Dilemma on two social networks obtained from actual relational data. We find very different cooperation levels on each of them that can not be easily understood in terms of global statistical properties of both networks. We claim that the result can be understood at the mesoscopic scale, by studying the community structure of the networks. We explain the dependence of the cooperation level on the temptation parameter in terms of the internal structure of the communities and their interconnections. We then test our results on community-structured, specifically designed artificial networks, finding perfect agreement with the observations in the real networks. Our results support the conclusion that studies of evolutionary games on model networks and their interpretation in terms of global properties may not be sufficient to study specific, real social systems. In addition, the community perspective may be helpful to interpret the origin and behavior of existing networks as well as to design structures that show resilient cooperative behavior.Comment: Largely improved version, includes an artificial network model that fully confirms the explanation of the results in terms of inter- and intra-community structur

Endodontic regenerative treatment for internal radicular resorption using bio-ceramic material, case report

The internal resorption of the internal radicular conduct is a process than can be both physiological or pathological, being the osteoclasts, odontoclasts and dentinoclast responsible for said process. 49-year-old female patient, refers orthodontic treatment at age 20, attends a dental check-up due to pain when chewing. Dental organ (DO) #11 was diagnosed with internal root resorption and symptomatic, suppurative apical periodontitis. Treatment started performing an endodontic access and taking a conductometry reading with an apical foramen locator, using a precision hybrid instrumentation technique and applying hypochlorite irrigation, the intra-canal was medicated with chemically pure calcium hydroxide for 7 days. The canal obturation was repaired infiltrating a bio-ceramic material (BIO-C Sealer) followed by the placement of the single cone using a vertical condensation technique

Colombia's cyberinfrastructure for biodiversity: Building data infrastructure in emerging countries to foster socioeconomic growth

Science and innovation are not a luxury but a prerequisite for social and economic development (Annan, 2003)

Query Extension Suggestions for Visual Query Systems Through Ontology Projection and Indexing

Ontology-based visual query formulation is a viable alternative to textual query editors in the Semantic Web domain for extracting data from structured data sources in terms of the skills and knowledge required. A visual query system is at any moment responsible for providing the user with query extension suggestions; however, suggestions leading to empty results are often not useful. To this end, in this article, we first present an approach for projecting OWL 2 ontologies into navigation graphs to be used for query formulation and then a solution where an efficient finite index is used to calculate non-ranked approximated extension suggestions for ontology-based visual query systems using navigation graphs. The results of our experiments suggest that one can efficiently project an ontology into a navigation graph, query it for running an interactive user interface, and suggest query extensions that do not lead to dead-ends

¿Es prioritario vacunar a niños de 3-11 años contra COVID-19 en Colombia?

En octubre 31 del 2021, Colombia inició la vacunación contra COVID-19 para niños de 3 a 11 años de edad, conla vacuna CoronaVac (Sinovac). Esta estrategia se implementó en ausencia de un informe técnico sobre la eficaciay seguridad de CoronaVac en niños, y sin una evaluación del costo-beneficio de esta, en comparación con otrasestrategias. En este comentario se consideran aspectos fundamentales que debieron tomarse en cuenta al ponderar silos beneficios de esta estrategia eran mayores que sus riesgos. Específicamente, la eficacia y seguridad de CoronaVacen niños de 3 a 11 años, la relación riesgo/beneficio de la estrategia, el rol de los niños en la transmisión comunitariade SARS-CoV-2, y las implicaciones éticas de la estrategia.En octubre 31 del 2021, Colombia inició la vacunación contra COVID-19 para niños de 3 a 11 años de edad, conla vacuna CoronaVac (Sinovac). Esta estrategia se implementó en ausencia de un informe técnico sobre la eficaciay seguridad de CoronaVac en niños, y sin una evaluación del costo-beneficio de esta, en comparación con otrasestrategias. En este comentario se consideran aspectos fundamentales que debieron tomarse en cuenta al ponderar silos beneficios de esta estrategia eran mayores que sus riesgos. Específicamente, la eficacia y seguridad de CoronaVacen niños de 3 a 11 años, la relación riesgo/beneficio de la estrategia, el rol de los niños en la transmisión comunitariade SARS-CoV-2, y las implicaciones éticas de la estrategia.En octubre 31 del 2021, Colombia inició la vacunación contra COVID-19 para niños de 3 a 11 años de edad, conla vacuna CoronaVac (Sinovac). Esta estrategia se implementó en ausencia de un informe técnico sobre la eficaciay seguridad de CoronaVac en niños, y sin una evaluación del costo-beneficio de esta, en comparación con otrasestrategias. En este comentario se consideran aspectos fundamentales que debieron tomarse en cuenta al ponderar silos beneficios de esta estrategia eran mayores que sus riesgos. Específicamente, la eficacia y seguridad de CoronaVacen niños de 3 a 11 años, la relación riesgo/beneficio de la estrategia, el rol de los niños en la transmisión comunitariade SARS-CoV-2, y las implicaciones éticas de la estrategia