Status of background-independent coarse-graining in tensor models for quantum gravity

A background-independent route towards a universal continuum limit in discrete models of quantum gravity proceeds through a background-independent form of coarse graining. This review provides a pedagogical introduction to the conceptual ideas underlying the use of the number of degrees of freedom as a scale for a Renormalization Group flow. We focus on tensor models, for which we explain how the tensor size serves as the scale for a background-independent coarse-graining flow. This flow provides a new probe of a universal continuum limit in tensor models. We review the development and setup of this tool and summarize results in the 2- and 3-dimensional case. Moreover, we provide a step-by-step guide to the practical implementation of these ideas and tools by deriving the flow of couplings in a rank-4-tensor model. We discuss the phenomenon of dimensional reduction in these models and find tentative first hints for an interacting fixed point with potential relevance for the continuum limit in four-dimensional quantum gravity.Comment: 28 pages, Review prepared for the special issue "Progress in Group Field Theory and Related Quantum Gravity Formalisms" in "Universe

Bioethanol As Basis for Regional Development in Brazil: An Input-Output Model With Mixed Technologies

Many issues of strategic importance that have emerged in recent years are contributing to the formulation of national policies for promoting biofuels worldwide. In the developed countries, such initiatives result mainly from concerns on energy security and greenhouse gases emissions. Developing countries envisage biofuels as a potential means to improve access to energy, increase income and employment, alleviate poverty, spur rural development, reduce oil imports and enhance exports of biomass products. These interests converge as to render bioethanol trade a unique opportunity for sustainable development. Despite its simplicity and ease of use, the basic input-output (i-o) model does not allow the representation of technology-differentiated sectors producing the same good or service. For instance, in Brazil, sugarcane can be collected manually or via harvesting machines and alcohol can be produced in plants appended to a sugar mill or in autonomous distilleries. An i-o model with mixed technologies was constructed for the purposes of the study. A linear technology is used to represent the sugarcane and ethanol sectors, whereas the remaining industries are characterized by the usual Leontief production function. Activity levels for the linear-technology sectors are set by a scenario analysis, avoiding the use of much more complicated mathematical tools, such as a computable general equilibrium (cge) model. The construction of the database was done in two stages. Firstly, an i-o table containing 42 sector and 80 commodities was estimated for the base year of 2002. Secondly, the sugarcane and ethanol industries were disaggregated from the sectors they appear in IBGE economic tables, based on detailed engineering information obtained from experts and specialized publications. The extended input-output model with mixed technologies was used to analyze the socioeconomic impacts of a large-scale expansion of bioethanol production in Brazil so as to replace 5% of the estimated global demand for gasoline in 2025. The resulting direct, indirect and induced effects indicate that if ethanol production is augmented in nearly 800%, GDP would increase by a factor of 11.4%, equivalent to approximately the entire economy in the Northeast region of Brazil, and more than 5 million of jobs would be created.

Regularization of energy-momentum tensor correlators and parity-odd terms

We discuss the problem of regularizing correlators in conformal field theories. The only way to do it in coordinate space is to interpret them as distributions. Unfortunately except for the simplest cases we do not have tabulated mathematical results. The way out we pursue here is to go to momentum space and use Feynman diagram techniques and their regularization methods. We focus on the energy-momentum tensor correlators and, to gain insight, we compute and regularize 2-point functions in 2d with various techniques both in coordinate space and in momentum space, obtaining the same results. Then we do the same for 2-point functions in 4d. Finally we turn to 3-point function in 4d, and concentrate on the parity-odd part. We derive in particular the regularized trace and divergence of the energy-momentum tensor in a chiral fermion model. We discuss the problems related to the parity-odd trace anomaly.Comment: 40 pages, 1 figure. v2: minor changes and typos correcte

Evaluation Of Three Radiographic Methods For Detecting Occlusal Caries Lesions

Aim: To compare, in vitro, the performance of three radiographic methods for the detection of occlusal caries in permanent teeth. Methods: A total of 96 extracted molars with no apparent occlusal cavitation were selected, they were photographed and radiographed under standardized conditions using conventional E-plus films and two digital systems, CDR and Sidexis. Two examiners analyzed all films and images, recording the presence and lesion depth. One quarter of the teeth were re-examined for intra- and interexaminer agreements. The teeth were subsequently bisected and examined under a stereomicroscope. The intra and interexaminer agreements and the diagnostic performance (sensitivity, specificity, accuracy and the area under receiver operating characteristic, ROC curve) of each method were evaluated. Results: Out of 96 occlusal surfaces, 41 were sound, 31 had lesions in enamel, and 24 had dentin lesions. Weighted Kappa values for intraexaminer agreement varied widely, depending on both the observer and method. The interexaminer agreement was higher for the digital images than for the conventional films. The area under the ROC curve for enamel and dentin caries (at D1 diagnostic threshold) was 0.55 for films, 0.60 for Schick and 0.54 for Sirona, which were not significantly different from each other. Conclusions: Digital images presented better results of interexaminer agreement; however, no additional effect in the diagnostic performance could be observed in comparison to conventional films.8267-7

Gestão democrática da educação : Para além do local/regional

Este trabalho descreve a experiência investigativa, em processo de conclusão, sobre gestão democrática em dois sistemas municipais de ensino do extremo sul catarinense (Brasil), sob nossa coordenação, no âmbito do FORGESB – Grupo de Estudos e Pesquisa sobre Formação e Gestão na Educação Básica, integrado ao Programa de Pós-graduação em Educação, PPGE, Universidade do Extremo Sul Catarinense, UNESC, Criciúma/Santa Catarina. Cabe ressaltar, que a descrição se desenvolve no diálogo com outros trabalhos e autores que discutem questões referentes à temática da gestão educacional, em especial, com o estudo de Gorostiaga (2011) acerca da “Participação e gestão escolar na Argentina e no Brasil”.Mesa 37/ Sociología política de la educación. Políticas educativas, Gestión institucional y el escenario de la educación como derechoFacultad de Humanidades y Ciencias de la Educació