1,280,941 research outputs found
On the definition of the classical connectives and quantifiers
Classical logic is embedded into constructive logic, through a definition of
the classical connectives and quantifiers in terms of the constructive ones.Comment: Why is this a Proof?, Festschrift for Luiz Carlos Pereira , 201
Codimension one foliations with numerically trivial canonical class on singular spaces
In this article, we describe the structure of codimension one foliations with
canonical singularities and numerically trivial canonical class on varieties
with terminal singularities, extending a result of Loray, Pereira and Touzet to
this context
Tilted excitation implies odd periodic resonances
This work was supported by the Brazilian agencies FAPESP and CNPq. MSB also acknowledges the Engineering and Physical Sciences Research Council grant Ref. EP/I032606/1. GID thanks Felipe A. C. Pereira for fruitful discussions.Peer reviewedPostprin
Consistently Solving the Simplicity Constraints for Spinfoam Quantum Gravity
We give an independent derivation of the Engle-Pereira-Rovelli spinfoam model
for quantum gravity which recently appeared in [arXiv:0705.2388]. Using the
coherent state techniques introduced earlier in [arXiv:0705.0674], we show that
the EPR model realizes a consistent imposition of the simplicity constraints
implementing general relativity from a topological BF theory.Comment: 6 pages, 2 figures, v2: typos correcte
Designing transformative spaces for sustainability in social-ecological systems
Transformations toward sustainability have recently gained traction, triggered in part by a growing recognition of the dramatic socio-cultural, political, economic, and technological changes required to move societies toward more desirable futures in the Anthropocene. However, there is a dearth of literature that emphasizes the crucial aspects of sustainability transformations in the diverse contexts of the Global South. Contributors to this Special Feature aim to address this gap by weaving together a series of case studies that together form an important navigational tool on the “how to” as well as the “what” and the “where to” of sustainability transformations across diverse challenges, sectors, and geographies. They propose the term “transformative space” as a “safe-enough” collaborative process whereby actors invested in sustainability transformations can experiment with new mental models, ideas, and practices that can help shift social-ecological systems onto more desirable pathways. The authors also highlight the challenges posed to researchers as they become “transformative space-makers,” navigating the power dynamics inherent in these processes. Because researchers and practitioners alike are challenged to provide answers to complex and often ambiguous or incomplete questions around sustainability, the ideas, reflections and learning gathered in this Special Feature provide some guidance on new ways of engaging with the world
Chinchillidae and Dolichotinae rodents (Rodentia: Hystricognathi: Caviomorpha) from the late Pleistocene of Southern Brazil
New records of rodents from the late Pleistocene Chuí Creek, Rio Grande do Sul State, southern Brazil, are here described. A partial dentary with fragmented cheek teeth is identified as Chinchillidae, Lagostomus Brookes cf. L. maximus (Desmarest). Other two specimens are identified as cheek teeth of Dolichotinae indet. (Caviidae). Pleistocene fossils of Lagostomus were previously reported for Argentina and Uruguay. The material of Lagostomus from Chuí Creek represents the first confidently record of this taxon Brazil. Pleistocene fossil remains of Dolichotinae have been found in Argentina, Uruguay and other areas of southern Brazil, though the Brazilian find lack precise stratigraphic information. These new records widen the paleobiogeographic distribution of Lagostomus and confirm the presence of Dolichotinae during the late Pleistocene of southern Brazil.Fil: Kerber, Leonardo. Fundação Zoobotânica do Rio Grande do Sul; BrasilFil: Pereira Lopes, Renato. Universidade Federal do Rio Grande do Sul; BrasilFil: Vucetich, María Guiomar. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Ribeiro, Ana Maria. Fundação Zoobotânica do Rio Grande do Sul; BrasilFil: Pereira, Jamil. Museu Coronel Tancredo Fernandes de Mello; Brasi
Semi-parametric models: an application in medicine
Conferência realizada em Rhodes, Grécia, de 23-28 de setembro de 2019.Modeling of medical data often requires the inclusion of non-linear forms of the predictors and, the Generalized
Additive Models (GAMs) can provide an excellent fit in the presence of non-linear relationships and significant noise in
the predictor variables. The accurate assessment of QT interval is of paramount importance since its prolongation (LQTS)
is a life threatening condition. The QT interval is affected by heart rate and gender and may be adjusted to improve the
detection of patients at increased risk. Bazett's formula is the most commonly used QT correction formula, and takes into
account only the heart rate assessed by the RR interval, and cut-of values of corrected QT are defined according to gender.
In this work we analyzed relevance of QRS, together with gender and RR to explain QT length using GAMs. Results
showed that QRS and gender are significant to non-pathological QT modelling.info:eu-repo/semantics/publishedVersio
Possible discovery of the r-process characteristics in the abundances of metal-rich barium stars
We study the abundance distributions of a sample of metal-rich barium stars
provided by Pereira et al. (2011) to investigate the s- and r-process
nucleosynthesis in the metal-rich environment. We compared the theoretical
results predicted by a parametric model with the observed abundances of the
metal-rich barium stars. We found that six barium stars have a significant
r-process characteristic, and we divided the barium stars into two groups: the
r-rich barium stars (, [La/Nd]\,) and normal barium stars. The
behavior of the r-rich barium stars seems more like that of the metal-poor
r-rich and CEMP-r/s stars. We suggest that the most possible formation
mechanism for these stars is the s-process pollution, although their abundance
patterns can be fitted very well when the pre-enrichment hypothesis is
included. The fact that we can not explain them well using the s-process
nucleosynthesis alone may be due to our incomplete knowledge on the production
of Nd, Eu, and other relevant elements by the s-process in metal-rich and super
metal-rich environments (see details in Pereira et al. 2011).Comment: 5 pages, 5 figures, accepted for publication in A&
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