Optimal Interest Rate Rules in Inflation Targeting Frameworks

This work describes the main characteristics of an inflation targeting regime and derives the optimal solution for interest rates according to an original methodology for two models based on the Phillips and IS curves containing general exogenous variables and a complete loss-function.

r-filters: a Hodrick-Prescott Filter Generalization

A two-parameter family of filters is proposed in which the HP filter is considered as the lowest order member. While the HP filter converges to linear time trend as the smoothing factor grows, the higher order members of the proposed family converge to higher order polynomial time trends. The filter order - the new parameter introduced - allows to set the filter selectivity. Furthermore, two different methods to implement these filters are presented.

Imaging material properties of biological samples with a Force Feedback Microscope

Mechanical properties of biological samples have been imaged with a \textit{Force Feedback Microscope}. Force, force gradient and dissipation are measured simultaneously and quantitatively, merely knowing the AFM cantilever spring constant. Our first results demonstrate that this robust method provides quantitative high resolution force measurements of the interaction The little oscillation imposed to the cantilever and the small value of its stiffness result in a vibrational energy much smaller than the thermal energy, reducing the interaction with the sample to a minimum. We show that the observed mechanical properties of the sample depend on the force applied by the tip and consequently on the sample indentation. Moreover, the frequency of the excitation imposed to the cantilever can be chosen arbitrarily, opening the way to frequency-dependent studies in biomechanics, sort of spectroscopic AFM investigations

Service life of shotcrete : investigation on the effect of set accelerating admixture

Le béton projeté par voie humide est une méthode de mise en place très populaire dans la construction de tunnels et le soutènement de parois dans les mines. L'utilisation d’un adjuvant accélérateur de prise offre des avantages significatifs en gain de productivité et pour la sécurité des travailleurs pendant la réalisation du travail. Cependant, l’effet de ces adjuvants, et particulièrement leur dosage, sur la durée de vie du béton projeté est mal compris et souvent négligé. Le dosage de l’adjuvant en chantier est souvent élevé, ce qui a pour conséquence de faire augmenter les coûts de production et réduire la qualité du béton. Cette recherche a pour objectif d’étudier l'influence de l'utilisation des accélérateurs de prise sur la durabilité du béton comme matériau, en considérant les particularités du béton projeté et en profitant des avancées faites en matière de prédiction de la durée de vie des bétons conventionnels. L’effet d’un adjuvant accélérateur de prise (à différents dosages) à base de sulfate d’aluminium (A/$) sera étudié. Les résultats permettront d’améliorer la qualité des applications de béton projeté dans l'industrie de la construction et les devis qui, chaque jour, sont plus exigeants et requièrent des performances de plus en plus élevées. Les données générées à partir des différents essais réalisés sont très intéressantes, car elles démontrent la complexité d’une telle étude à cause des changements non proportionnels des caractéristiques du béton avec différents dosages d’accélérateur de prise. De plus, les données générées illustrent bien l'influence de l’adjuvant accélérateur de prise sur la qualité du béton.Wet-mix shotcrete is a widely used placement method in tunnelling and ground support. The use of a set accelerating admixture provides significant advantages in terms of productivity gains and worker safety during work progress. However, knowledge about adverse effects linked the use of set accelerator admixture (and particularly its dosage) is very limited. Indeed, dosage control is sometimes overlooked on the job site or the accelerator may be misguidedly overdosed, with the consequence of increasing costs and reducing the quality of the in-place shotcrete. The goal of this research is to study and better understand the effects of the use of set accelarating admixture on the durability of concrete as a material, starting with the particularities of shotcrete and taking advantage of the latest tools in modelling service life of conventional concretes. An alkali-free set accelerating admixture (at different dosages) based on aluminium-sulphate salts (A/$) will be investigated. The results will help improve the quality of shotcrete applications in the construction industry, and specifications which are increasingly demanding and require everimproving performances. The data generated from the several tests performed is very interesting, because it shows the intricacies of such an investigation due to the non-linear changes of concrete using different set accelerator dosages. It also demonstrates clearly the effects of using high dosages of set accelerating admixtures on the quality of shotcrete

Spectroscopic investigation of local mechanical impedance of living cells

The mechanical properties of PC12 living cells have been studied at the nanoscale with a Force Feedback Microscope using two experimental approaches. Firstly, the local mechanical impedance of the cell membrane has been mapped simultaneously to the cell morphology at constant force. As the force of the interaction is gradually increased, we observed the appearance of the sub-membrane cytoskeleton. We shall compare the results obtained with this method with the measurement of other existing techniques. Secondly, a spectroscopic investigation has been performed varying the indentation of the tip in the cell membrane and consequently the force applied on it. In contrast with conventional dynamic atomic force microscopy techniques, here the small oscillation amplitude of the tip is not necessarily imposed at the cantilever first eigenmode. This allows the user to arbitrarily choose the excitation frequency in developing spectroscopic AFM techniques. The mechanical response of the PC12 cell membrane is found to be frequency dependent in the 1 kHz - 10 kHz range. The damping coefficient is reproducibly observed to decrease when the excitation frequency is increased.Comment: 8 pages, 8 figure

Desenvolvendo um Cérebro Ágil: como os Hábitos Influenciam na Aprendizagem, Memorização e como Obter Melhor Desempenho

Objetivo: O objetivo deste artigo é mostrar como os hábitos podem ter influencia na aprendizagem, memorização e de que forma os podemos otimizar para obter um melhor desempenho.   Estrutura teórica: A estrutura teórica do estudo inclui a revisão teórica de vários artigos sobre a temática predominando a escolha de journals com boa qualificação.   Desenho/método/aprovação:A aprendizagem e a memorização são fundamentais para o sucesso pessoal, profissional e acadêmico. Inúmeros fatores contribuem para melhorar a dinâmica de estudos e retenção de informações, como a dieta, sono, atenção sustentada, entre outros. Em suma, este artigo apresenta uma visão abrangente do tema, com descobertas relevantes e aponta caminhos seguros para um melhor desempenho.   Conclusões: A memorização e a aprendizagem dependem de inúmeros fatores que podem afetar suas habilidades. Alimentos atuam como fontes de proteínas e ao mesmo tempo podem surgir alterando o DNA com a epigenética, assim como exercícios e hábitos. Para desenvolver um cérebro ágil é necessário conhecer suas estruturas a fundo e trabalhar em cada detalhe. Contudo, torna-se importante trabalhar com moderação e baseado em dados, excessos podem causar reações indesejáveis. Ainda assim, é possível alcançar este resultado.   Pesquisa, implicações práticas e sociais: O principal objetivo deste estudo foi demonstrar que podemos alcançar resultados diferentes no que diz respeito ao desenvolvimento do nosso cérebro aplicando as técnicas corretas e seguindo uma série de métodos.   Originalidade/valor: Aprendizado por reforço é considerado pela ciência como o mais efetivo método de estudos, trazendo benefícios duradouros