Does Speculation Affect Oil Price Volatiliy?

O objetivo do presente estudo é tentar perceber se a atividade especulativa é o fator principal na repentina subida de preços do crude no spot market, especialmente no mais recente episódio especulativo que ocorreu entre 2003 e a primeira metade de 2008. A base do nosso estudo assenta num modelo já existente de vectores autoregressivos que foi proposto por Kilian e Murphy (2014); um modelo estrutural do mercado global do crude que permite uma análise de choques de procura e oferta e também choques especulativos. A originalidade do modelo apresentado nesta dissertação, relativamente ao daqueles autores, reside na introdução de um componente especulativo para medir os spreads usando contratos de futuros do crude. Com o output do modelo estrutural apresentado conseguimos excluir a teoria da especulação como fator na subida do preço do crude; no entanto, os nossos resultados sugerem que a subida se deve a um aumento na procura conduzido por um crescimento económico inesperado na economia global. As conclusões deste estudo permitem confirmar as de outras obras literárias da mesma natureza e revelam a importância dos futuros enquanto instrumentos preditivo

Femtosecond laser ablation of dentin

The surface morphology, structure and composition of human dentin treated with a femtosecond infrared laser (pulse duration 500 fs, wavelength 1030 nm, fluences ranging from 1 to 3 J cm(-2)) was studied by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The average dentin ablation threshold under these conditions was 0.6 +/- 0.2 J cm(-2) and the ablation rate achieved in the range 1 to 2 mu m/pulse for an average fluence of 3 J cm(-2). The ablation surfaces present an irregular and rugged appearance, with no significant traces of melting, deformation, cracking or carbonization. The smear layer was entirely removed by the laser treatment. For fluences only slightly higher than the ablation threshold the morphology of the laser-treated surfaces was very similar to the dentin fracture surfaces and the dentinal tubules remained open. For higher fluences, the surface was more porous and the dentin structure was partially concealed by ablation debris and a few resolidified droplets. Independently on the laser processing parameters and laser processing method used no sub-superficial cracking was observed. The dentin constitution and chemical composition was not significantly modified by the laser treatment in the processing parameter range used. In particular, the organic matter is not preferentially removed from the surface and no traces of high temperature phosphates, such as the beta-tricalcium phosphate, were observed. The achieved results are compatible with an electrostatic ablation mechanism. In conclusion, the high beam quality and short pulse duration of the ultrafast laser used should allow the accurate preparation of cavities, with negligible damage of the underlying material

CoR's Faster Route over Myrinet

In this paper we concentrate in the efforts made to exploit the performance of Myrinet to build a faster communication route into CoR1. By accessing the Myrinet interface through GM2, we achieved low latency and high bandwidth message passing without the overhead of a higher level protocol stack, system calls or interrupts. CoR is an ongoing project unique in its design goal of combining multithreading, message passing and distributed shared memory with facilities to dynamically select from different transport media and protocols the one that best fits communication and interaction requirements. The ability to mix CoR and PVM calls in the same program brings numerous benefits to the application developer familiar with PVM, notably: 1) new transport communication layers; PvmRouteMyrinet and PvmRouteUdp; 2) migration mechanisms for exploiting fine grain message passing; 3) thread-safe communication PVM API; 4) object-oriented distributed shared memory

pCoR - a protoype for resource oriented computing

In this paper we present CoR a resource oriented computing model that address the question of how to integrate user-level fine-grained multithreading, communication and coordination into a cluster of symmetrical multiprocessor computers. To support the design of complex distributed application using the proposed paradigm we built pCoR a run-time system which has new areas that represents extensions to the strict shared memory and message passing models supported by other platforms: remote operations, dynamic domains, communication ports, multithreading management, shared memory, replication and partition are some of its distinguished features. In addition, it provides a thread-safe transport communication layer to take advantage of modern high-performance commodity hardware/software like Myrinet network

Temas relacionados à educação na produção científica periódica dos bolsistas de produtividade em pesquisa da área de ciência da informação no Brasil.

Objective. To analyze issues related to Education in the scientific production of Information Science, derived from articles of Information Science researchers in Brapci between the years 1972 and 2015. Design/Methodology/Approach. The bibliometric procedures and their production and citation indicators were used. A database was constructed from the scientific production of 47 researchers. Articles were retrieved by using the following search terms: “education”, “teaching”, “learning” and “curriculum”. Vantage Point®, Microsoft Excel®, UCINET® and Netdraw® were employed as data processing and analysis tools. Results/Discussion. The major themes were related to Library and Library Science; Technology; Information Literacy; Archives and Archives; Universities and Distance Education. It brings the most cited authors and the most intense relationships between cited authors and keywords. Conclusions. The most cited authors turn to studies on information policies, literacy, ethical issues and information communication. Originality/Value. The study is sustained by the need to clarify the interdisciplinary and inter-domains relations between Information Science and Education

Avaliação de Uma Rede Neural Artificial Como Modelo Regressor Para Séries Temporais

Técnicas de predição de demanda são utilizadas em inúmeros ramos da indústria, com o objetivo de agregar valor ao negócio das empresas, especialmente por meio da busca pelo dimensionamento ótimo dos recursos de produção. A predição de demanda em refeitórios, com o intuito de balancear a quantidade de alimento produzido, buscando um melhor aproveitamento dos ingredientes, é um desafio, pois fatores como a quantidade de usuários, o tempo de atendimento e o tipo de alimento utilizado podem ser bastante variáveis neste tipo de problema. O estudo das filas, neste contexto, é de primordial importância, dado que, conhecendo suas características, podem-se estimar, por meio de previsão, informações que podem melhorar a qualidade de atendimento. O presente trabalho teve por finalidade utilizar modelos baseados em Redes Neurais Artificiais (RNA) para realizar regressões em uma série temporal personalizada, gerada por meio de metodologia própria, mediantes os dados coletados in loco no restaurante do IFMG - Campus Bambuí. Teve-se por principal objetivo desenvolver um modelo computacional que fosse capaz de descrever o comportamento para os intervalos de tempo no atendimento dos usuários. Por meio deste recurso, pôde-se gerar informações importantes para a tomada de decisão, como os horários de maior e menor pico de atendimento.Palavras-chave: Redes neurais artificiais, regressão, séries temporais.==================================================================================Demand prediction techniques are used in numerous industry sectors with the aim of adding value to the business of the companies, especially through the search for optimal sizing of production resources. The prediction of demand in restaurants with the intention of balancing the quantity food produced looking for better use of ingredients is a challenge, since factors like the quantity of users, the time of service and the kind of food can be quite variable in this type of problem. The study of queue, in this context, is of paramount importance, given that, knowing its characteristics, it is possible to estimate, by means of prediction, information that can improve service quality. Present work had the purpose of using models based on Artificial Neural Networks (ANN) to perform regressions in a personalized time series, generated through its own methodology with data collected in the restaurant of the IFMG - Campus Bambuí. The main objective was to develop a computational model that would be able to describe the behavior for the time intervals in the restaurant customer service. Through this resource, it was possible to generate important information for decision making, such as the peak times of higher and lower demands.Keywords: Artificial neural networks, regression, time series

Ageing effects on the wettability behavior of laser textured silicon

In the present work we investigate the ageing of acid cleaned femtosecond laser textured silicon surfaces. Changes in the surface structure and chemistry were analysed by Rutherford backscattering spectrometry (RBS) and X-ray photoelectron spectroscopy (XPS), in order to explain the variation with time of the water contact angles of the laser textured surfaces. It is shown that highly hydrophobic silicon surfaces are obtained immediately after laser texturing and cleaning with acid solutions (water contact angle >120 degrees). However these surfaces are not stable and ageing leads to a decrease of the water contact angle which reaches a value of 80 degrees. XPS analysis of the surfaces shows that the growth of the native oxide layer is most probably responsible for this behavior. (C) 2010 Elsevier B.V. All rights reserved

The design and production by additive manufacturing: case of face shields / O projeto e a produção por manufatura aditiva: caso dos protetores faciais.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) quickly reached a global pandemic status in 2020 creating a huge demand for personal protective and medical equipment. Additive manufacturing, in this context, became a solution to alleviate the demands of the healthcare sector. This article presents how lean manufacturing approaches and Design for Additive Manufacturing (DfAM) helped to implement an additive manufacturing line for face shields production. The methodological approach was action research, in which undergraduate and graduate students, professionals, and researchers joined forces to produce and deliver 27,000 face shields. The article contributes towards the implementation of additive manufacturing for small batches production of product final parts and offers content for future discussions regarding production digitization

The effects of musical auditory stimulation on heart rate autonomic responses to driving: A prospective randomized case-control pilot study

Stress induced by driving has been revealed to increase the chances of cardiovascular complications and is involved or related to traffic accidents. In order to develop strategies to avoid health problems during driving we aimed to evaluate the acute effects of auditory stimulation with music on heart rate variability (HRV) during driving in congested urban traffic. This is a prospective cross-sectional randomized controlled pilot study conducted with five healthy women. Subjects were evaluated on two different random days, whose order of execution was established through a randomization process. In the music protocol the volunteers were exposed to music for the entire 20 min of traffic while in the control protocol the subjects performed the same procedures but were not exposed to any music. We noted that all Higuchi fractal dimension parameters except Kmax 10, Kmax 130 and Kmax 140 were reduced between pre-driving in the control protocol vs. driving in the control protocol. The same changes were noted between pre-driving in the music protocol vs. driving in the control protocol. In conclusion, musical auditory stimulation improved nonlinear HRV changes induced by driving

Calculation of the cost of the basic food basket in Vitória da Conquista – BA, in the context of the Sars-Cov-2 pandemic: methodological procedures and evaluation of results

Este artigo tem como objetivo analisar os ajustes realizados nos procedimentos metodológicos para a coleta de preços e cálculo do custo da Cesta Básica em Vitória da Conquista, no contexto da SARS-CoV-2 (COVID 19). Em particular, busca-se avaliar a eficácia das rotinas da pesquisa de preços de forma remota para a coleta de preços, com padronização, uniformidade e efetividade. O cálculo do custo da Cesta Básica se assenta em uma abordagem interdisciplinar e multidimensional, em especial nos pressupostos teóricos e conceituais da Economia Política, da Microeconomia e da Socioeconomia, bem como, na aplicação de instrumentos analíticos que proporcionem diretrizes para a formulação de políticas de melhoria do nível de renda e bem-estar da população. A experiência de pesquisa de preços para o cálculo do custo da Cesta Básica, realizada de forma remota, mediante a utilização de plataformas digitais, representou um aperfeiçoamento da metodologia e das técnicas de coleta de dados, permitindo a validação e a continuidade da pesquisa.The objective of this article is to analyze the adjustments made to the methodological procedures for collecting prices and calculating the cost of the Basic Basket in Vitória da Conquista, in the context of SARS-CoV-2 (COVID 19). In particular, it seeks to remotely assess the effectiveness of price survey routines for price collection, with standardization, uniformity and effectiveness. The calculation of the cost of the Food Basket is based on an interdisciplinary and multidimensional approach, in particular on the theoretical and conceptual assumptions of Political Economy, Microeconomics and Socioeconomics, as well as on the application of analytical instruments that provide guidelines for the formulation of policies for improvement in the level of income and well-being of the population. The experience of researching prices for calculating the cost of the Basic Basket, carried out remotely, using digital platforms, represented an improvement in the methodology and techniques for data collection, allowing for validation and continuity of the research