Combination of Lyapunov Functions and Density Functions for Stability of Rotational Motion

Lyapunov methods and density functions provide dual characterizations of the solutions of a nonlinear dynamic system. This work exploits the idea of combining both techniques, to yield stability results that are valid for almost all the solutions of the system. Based on the combination of Lyapunov and density functions, analysis methods are proposed for the derivation of almost input-to-state stability, and of almost global stability in nonlinear systems. The techniques are illustrated for an inertial attitude observer, where angular velocity readings are corrupted by non-idealities

Systematics of species of the genus Akodon (Rodentia: Sigmodontinae) in southeastern Brazil and implications for the biogeography of the Campos de Altitude

http://deepblue.lib.umich.edu/bitstream/2027.42/111041/1/MP197.pd

Acerca dos resíduos minerais nas pastas pelo sulfato. Contribuição para o estudo da influência das técnicas de preparação laboratorial sobre a composição mineral de pastas de eucalipto

No Laboratório de Tecnologia Florestal procedeu-se a uma série de análises dos componentes minerais de pastas preparadas pelo sulfato a partir de amostras de Eucalyptus globulus e E. saligna, tendo sido usados digestores de capacidades e de materiais diferentes. Quer para a dissolução dos reagentes quer para a lavagem e formação da folha de ensaio recorreu-se a água de proveniências diversas nomeadamente a água destilada. Os resultados obtidos foram comparados entre si e também confrontados com os resultantes da análise de pastas industriais. Como conclusões imediatas, verificámos que, embora o teor em cinzas totais se não afastasse muito de ensaio para ensaio, a composição mineral dessas cinzas era notavelmente afectada, reflectindo a influência de dois grupos de factores: composição da matéria-prima original transformada em pasta e técnica de fabricação adoptada, tendo marcada importância a metodologia seguida nas operações que se processam até à formação da folha de amostra. Relativamente a este último interveniente, é de realçar as discrepâncias entre pastas preparadas por métodos laboratoriais e as de origem industrial, tornando-se impraticável qualquer extrapolação. Salienta-se a necessidade de realizar estudos que contribuam para uma normalização aceitável dos métodos laboratoriais de operação, tomando em conta não só o equipamento como as técnicas de lavagem e subsequentes tratamentos aplicados, de modo a obterem-se amostras de características significativasinfo:eu-repo/semantics/publishedVersio

Advanced hydrogels based on natural macromolecules: chemical routes to achieve mechanical versatility

Advances in synthetic routes to chemically modify natural macromolecules such as polysaccharides and proteins have allowed designing functional hydrogels able to tackle current challenges in the biomedical field. Hydrogels are hydrophilic three-dimensional systems able to absorb or retain a large volume of water, prepared from a low percentage of precursor macromolecules. The typical fragile elastic structure of common hydrogel formulations often limits their usage. Three main fabrication strategies involving several compounds or multimodified materials known as double networks, dual-crosslinked networks, and interpenetrating networks have been explored to impart mechanical strength to hydrogels. Widely investigated for synthetic polymers, these approaches allow obtaining added-value hydrogels with a large spectrum of mechanical properties. Advances in the development of such hydrogels with biomacromolecules as main constituent materials have enabled the fabrication of hydrogels with improved key properties for medical use, including biocompatibility, controlled release of active substances and tailored biodegradability, while exploring sustainable sources. This review describes recent advances in the use of proteins, as well as natural and semi-synthetic polymers for the fabrication of hydrogels for biomedical applications. Structures processed via double network, dual-crosslinked, or interpenetrating network strategies are reviewed, and emphasis is given to the type of chemical modifications and reactions, as well as the covalent and non-covalent interactions/bonds involved in those mechanisms.publishe

NEW SEISMIC SOURCE ZONE MODEL FOR PORTUGAL AND AZORES

The development of seismogenic source models is one of the first steps in seismic hazard assessment. In seismic hazard terminology, seismic source zones (SSZ) are polygons (or volumes) that delineate areas with homogeneous characteristics of seismicity. The importance of using knowledge on geology, seismicity and tectonics in the definition of source zones has been recognized for a long time [1]. However, the definition of SSZ tends to be subjective and controversial. Using SSZ based on broad geology, by spreading the seismicity clusters throughout the areal extent of a zone, provides a way to account for possible long-term non-stationary seismicity behavior [2,3]. This approach effectively increases seismicity rates in regions with no significant historical or instrumental seismicity, while decreasing seismicity rates in regions that display higher rates of seismicity. In contrast, the use of SSZ based on concentrations of seismicity or spatial smoothing results in stationary behavior [4]. In the FP7 Project SHARE (Seismic Hazard Harmonization in Europe), seismic hazard will be assessed with a logic tree approach that allows for three types of branches for seismicity models: a) smoothed seismicity, b) SSZ, c) SSZ and faults. In this context, a large-scale zonation model for use in the smoothed seismicity branch, and a new consensus SSZ model for Portugal and Azores have been developed. The new models were achieved with the participation of regional experts by combining and adapting existing models and incorporating new regional knowledge of the earthquake potential. The main criteria used for delineating the SSZ include distribution of seismicity, broad geological architecture, crustal characteristics (oceanic versus continental, tectonically active versus stable, etc.), historical catalogue completeness, and the characteristics of active or potentially-active faults. This model will be integrated into an Iberian model of SSZ to be used in the Project SHARE seismic hazard assessment

Key factors influencing the sale of bulls in livestock auctions

This research determines which factors most influence the purchase price of bulls in livestock auctions in the State of Rio Grande do Sul, Southern Brazil. Hence, 760 beef bulls sold in eleven different auctions between August and November 2013 were analysed. The data consists of: breed, muscularity (MUSC), frame (FRAME), body condition score (BCS), scrotal circumference (SC) and body weight (BW). Other data such as the animal entry order and the purchase price of the bulls was collected during the auction. A linear generalized model was used to evaluate the interaction of each variable with the purchase price of the bulls. An ANOVA with Tukey post-hoc was used to compare the differences between the categories that influenced the purchase price of bulls and were realized in the software SPSS 20.0. All breeds presented declining pricesfrom the first to the second entry order and increasing purchase prices from the order third to forth. Bulls with large frame received higher purchase prices independent of the auction order, except for the second order of entry, in which medium and small animals were more valued. Angus bulls obtained the highest prices in relation to the breeds Brangus and Hereford. The frame and breed constituted the main phenotypic characteristics that influence in price. In addition, the order of entry of bulls in the ring influence the purchase price

Temperature-responsive nanomagnetic logic gates for cellular hyperthermia

While a continuous monitoring of temperature at the micro- and nano-scales is clearly of interest in many contexts, in many others a yes or no answer to the question "did the system locally exceed a certain temperature threshold?" can be more accurate and useful. This is the case of hard-to-detect events, such as those where temperature fluctuations above a defined threshold are shorter than the typical integration time of micro/nanothermometers and systems where fluctuations are rare events in a wide time frame. Herein we present the synthesis of iron selenide magnetic nanoplatelets and their use as non-volatile logic gates recording the near infrared (NIR) dose that triggers a temperature increase above a critical temperature around 42 °C in prostate cancer cell cultures. This use is based on the bistable behavior shown by the nanoplatelets below a magnetic phase transition at a tunable temperature T C and on their photothermal response under NIR light. The obtained results indicate that the synthesized nanomagnets may be employed in the future as both local heaters and temperature monitoring tools in a wide range of contexts involving systems which, as cells, are temperature-sensitive around the tunable T C

Estudo da Variação Intradiária das Concentrações de Pólen de Gramíneas na Atmosfera de Portugal Continental

Introdução: O pólen da família das Poaceae (gramíneas) é uma das principais fontes de aeroalergénios no mundo, particularmente na Europa Mediterrânica. Representa, por isso, um importante factor de risco de asma, rinite e/ou conjuntivite alérgica e constitui a principal causa de polinose em Portugal. Objectivo: Analisar a variação intradiária das concentrações de pólen de gramíneas na atmosfera das 5 estações de monitorização continentais da Rede Portuguesa de Aerobiologia (RPA): Porto, Coimbra, Lisboa, Évora e Portimão. Métodos: Neste estudo utilizaram -se os dados diários e horários das monitorizações de pólen de gramíneas das cinco estações de monitorização continentais da RPA, ao longo de 7 anos (2002 -2008). Resultados: Entre as localidades encontraram -se diferenças significativas, em termos de Estudo da variação intradiária das concentrações de pólen de gramíneas na atmosfera de Portugal Continental O pólen atmosférico de gramíneas constitui a principal causa de rinite, asma, conjuntivite e eczema nos indivíduos alérgicos ao pólen na área Mediterrânica1,2, nomeadamente em Portugal3,4. Dado que o pólen, particularmente o pólen de gramíneas, é um factor de risco para as doenças alérgicas respiratórias exercendo um impacto negativo sobre a qualidade de vida dos indivíduos sensibilizados, é de particular interesse, quer dos profissionais de saúde, quer do doente conhecer a sua distribuição intradiária, ou seja a variação horária das concentrações de pólen de gramíneas ao longo do dia, de modo a adequar de forma mais eficaz medidas de evicção e de intervenção terapêutica. curvas horárias. O pólen encontrou -se presente na atmosfera durante 24 horas em todas as localidades, e os valores das concentrações horárias variaram ao longo do dia e de ano para ano. As concentrações mais baixas registaram -se entre as 22 e as 6 horas e as mais elevadas, entre as 7 e as 21 horas, as quais em Évora ultrapassaram os 30 grãos de pólen/m3/hora. Em geral, registaram -se 2 picos de concentrações máximas, um de manhã (9 -10 horas) ou à tarde (12 -13 horas) e outro no final da tarde / início da noite (19 -20 horas). Conclusões: O ritmo diurno difere muito de local para local. Cada localidade tem o seu próprio padrão de variação das concentrações horárias do pólen atmosférico de gramíneas que se pode dever, quer às diferentes espécies presentes, quer às diferentes condições ambientais. O risco de exposição variou de localidade para localidade e ao longo do dia, sendo o Porto a localidade onde este é menor, enquanto Évora apresenta o maior risco

Gluon Propagator on Coarse Lattices in Laplacian Gauges

The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau gauge in the asymptotic limit. Like Landau gauge, it respects Lorentz invariance, but it is free of Gribov copies; the gauge fixing is unambiguous. In this paper we study the infrared behavior of the lattice gluon propagator in Laplacian gauge by using a variety of lattices with spacings from $a = 0.125$ to 0.35 fm, to explore finite volume and discretization effects. Three different implementations of the Laplacian gauge are defined and compared. The Laplacian gauge propagator has already been claimed to be insensitive to finite volume effects and this is tested on lattices with large volumes.Comment: RevTex 4.0, 14 pages, 9 colour figures; Correction to Reference