Etnomatemática Do Sistema De Contagem Guarani Das Aldeias Itaty, Do Morro Dos Cavalos, E M'biguaçu

The Guarani are one of several indigenous Brazilian tribes. Since the first Portuguese colonizers arrived to Brazil, the culture and costumes - including mathematical knowledge - and practices of Guarani and other indigenous people were considered inferior and unworthy. Considering this panorama and taking into account the multicultural features of Brazilian school, we present this article with the objective of analyzing the counting system and some graphical symbols of two Guarani tribes, the Itaty tribe, settled at the "Morro dos Cavalos" and M'Biguaçu tribe, located between the cities Palhoça and Biguaçu in Santa Catarina State, Brazil. This ethnographic case study was carried out through interviews with leaders of the Guarani tribes mentioned above. The present study is based on the theoretical principles of the "Ethnomatematics Program". The results of our analyses made evident that the counting system as well as the symbols employed are strongly correlated to these people's culture, thus playing roles both in quantification and in what we call in this paper as qualitative function.3056992101

Millimeter-scale unipolar transport in high sensitivity organic-inorganic semiconductor X-Ray detectors

Hybrid inorganic-in-organic semiconductors are an attractive class of materials for optoelectronic applications. Traditionally, the thicknesses of organic semiconductors are kept below 1 micron due to poor charge transport in such systems. However, recent work suggests that charge carriers in such organic semiconductors can be transported over centimeter length scales opposing this view. In this work, a unipolar X-ray photoconductor based on a bulk heterojunction architecture, consisting of poly(3-hexylthiophene), a C70 derivative and high atomic number bismuth oxide nanoparticles operating in the 0.1 – 1 mm thickness regime is demonstrated, having a high sensitivity of ~160 µCmGy-1cm-3. The high performance enabled by hole drift lengths approaching a millimeter facilitates a device architecture allowing a high fraction of the incident X-rays to be attenuated. An X-ray imager is demonstrated with sufficient resolution for security applications such as portable baggage screening at border crossings and public events and scalable medical applications

Genetic evaluation of age at first calving for Guzerá beef cattle using linear, threshold, and survival Bayesian models

Age at first calving (AFC) is characterized as a censored trait due to missing values provided by recording mistakes and nonoccur-rence or delay in calving communication. In this context, we aimed to compare several statistical methods for genetic evaluation of AFC in Guzerá beef cattle under a Bayesian approach. Seven different methods were used for this purpose. The traditional linear mixed model (LM), which considers only uncensored records; the LM with simulated records (SM), which is based on data augmentation framework; the penalty method, in which a constant of 21 d was added to censored records; the bivariate threshold-linear method considering (TLcens) or not (TLmiss) censored information; and the piecewise Weibull proportional hazards model considering (PWPHcens) or not (PWPH) censored records. Heritability estimates ranged from 0.19 (TLcens) to 0.28 (SM) in non-survival approaches; and 0.40 and 0.46 to PWPH and PWPHcens methods, respectively. In general, breeding values correlations between different methods and the percentage of selected bulls in common indicated reranking, with these correlation ranging from -0.28 (between SM and PWPH) to 0.99 (between TLmiss and LM). The traditional LM, which considers only uncensored records, should be preferred due to its robustness and simplicity. Based on cross-validation analyses, we conclude that the TLmiss could be also a suitable alternative for breeding value prediction, and censored methods did not improve the analysis

Censored Bayesian models for genetic evaluation of age at first calving in Brazilian Brahman cattle

We compared different Bayesian models to handle censored data for genetic parameters estimation of age at first calving (AFC) in Brazilian Brahman cattle. Data from females with AFC above 1825 days of age were assumed to have failed to calve and were considered as censored records. Data including information of 53, 703 cows were analyzed through the following methods: conventional linear model method (LM), which consider only uncensored records; simulation method (SM), in which the data were augmented by drawing random samples from positive truncated normal distributions; penalty method (PM), in which a constant of 21 days was added to censored records; and the bivariate threshold-linear method (TLcens). The LM was the most suited for genetic evaluation of AFC in Brazilian Brahman cattle based on the predictive ability evaluation through cross-validation analysis. The similar results for LM and PM regarding Spearman correlations, and the higher percentages of selected animals in common, indicated that there was not relevant reranking of animals when censored records were used. In summary, the heritability estimates for AFC ranged from 0.09 (TLcens) to 0.20 (LM). Given its poor predictive performance, the SM is not recommended for handling censored records for genetic evaluation of AFC

II Ciclo de Conferências : Conselho Técnico-Científico: temas atuais em investigação

A obra é constituída pelos resumos das comunicações apresentadas pelos docentes da Escola Superior Agrária do Instituto Politécnico de Castelo Branco e são referentes aos projetos de investigação nos quais estão envolvidos.O atual Conselho Técnico-Científico (CTC) da Escola Superior Agrária de Castelo Branco (ESACB) tomou posse em fevereiro de 2012, tendo decidido dar continuidade ao ciclo de conferências iniciado pelo CTC anterior. Os trabalhos de Investigação, Inovação e Experimentação que foram apresentados demonstram não só o dinamismo e a ligação com a comunidade, como também a preocupação na identificação e resolução de problemas, que acrescentem valor aos produtos e processos que se situam no âmbito das competências desta Escola. Sendo este um objetivo prioritário da missão do IPCB/ESA, a divulgação destas conferências permite chegar a um público mais alargado e abrir caminhos para a concretização de novos projetos, que contribuam de forma efetiva para o desenvolvimento e aumento da competitividade da região e do país

Growth model with restricted surface relaxation

We simulate a growth model with restricted surface relaxation process in d=1 and d=2, where d is the dimensionality of a flat substrate. In this model, each particle can relax on the surface to a local minimum, as the Edwards-Wilkinson linear model, but only within a distance s. If the local minimum is out from this distance, the particle evaporates through a refuse mechanism similar to the Kim-Kosterlitz nonlinear model. In d=1, the growth exponent beta, measured from the temporal behavior of roughness, indicates that in the coarse-grained limit, the linear term of the Kardar-Parisi-Zhang equation dominates in short times (low-roughness) and, in asymptotic times, the nonlinear term prevails. The crossover between linear and nonlinear behaviors occurs in a characteristic time t_c which only depends on the magnitude of the parameter s, related to the nonlinear term. In d=2, we find indications of a similar crossover, that is, logarithmic temporal behavior of roughness in short times and power law behavior in asymptotic times

Cistercian Pavements from Santa Maria de Alcobaça Abbey: first examples of tin-glazed tiles in Portugal

The Mosteiro de Alcobaça (Alcobaça Monastery, founded in 1153) was built to the image of Clairvaux Abbey, founded by the Cistercian abbot St. Bernard. In many ways Alcobaça mirrored the original concepts of the Cistercian Order, with an austere architectural style and shedding signs of richness. The glazed tiles found on the pavement of the deambulatory and some adjacent chapels are some of the first examples of lead-tin glazes in Christian Portugal. For the first time, these tiles were analytically characterized, to determine their chemical composition, production technology and decoration technique. The analytical techniques used were μ-PIXE (particle-induced X-ray emission), SEM-EDS (scanning electron microscopy with energy-dispersive X-ray spectrometry), and μ-Raman spectroscopy

Self-avoiding fractional Brownian motion - The Edwards model

In this work we extend Varadhan's construction of the Edwards polymer model to the case of fractional Brownian motions in $\R^d$, for any dimension $d\geq 2$, with arbitrary Hurst parameters $H\leq 1/d$.Comment: 14 page