Conjuntos minimais de sistemas lineares por partes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Piecewise Linear Systems with Closed Sliding Poly-Trajectories

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Equivalent Carbon Dioxide Capture and Storage Processes in Offshore Petroleum Production Facilities

The present study approaches the economic and technical evaluation of equivalent carbon dioxide (CO(2) eqv.) capture and storage processes, considered in a proposal case compared to a base case. The base case considers an offshore petroleum production facility, with high CO(2) content (4 vol%) in the composition of the produced gas and both CO(2) and natural gas emissions to the atmosphere, called CO(2) eqv. emissions. The results obtained with this study, by using a Hysys process simulator, showed a CO(2) emission reduction of 65% comparing the proposal case in relation to the base case.

On the relation between the conditional moment closure and unsteady flamelets

We consider the relation between the conditional moment closure (CMC) and the unsteady flamelet model (FM). The CMC equations were originally constructed as global equations, while FM was derived asymptotically for a thin reaction zone. The recent tendency is to use FM-type equations as global equations. We investigate the possible consequences and suggest a new version of FM: coordinate-invariant FM (CIFM). Unlike FM, CIFM complies with conditional properties of the exact transport equations which are used effectively in CMC. We analyse the assumptions needed to obtain another global version of FM: representative interactive flamelets (RIF), from original FM and demonstrate that, in homogeneous turbulence, one of these assumptions is equivalent to the main CMC hypothesis.

Production and quality of cotton fibers in relation to solar radiation

The present paper refers to a research work carried out at the Dept. of Agriculture and Horticulture of ESALQ, University of São Paulo, in Piracicaba, State of São Paulo (latitude 22º42'S, longitude 47º33' WG and altitude 546 m). Sowing at different times and using artificial cover, an attempt was made to evaluate the behavior of cultivar IAC 17 of cotton (Gossypium hirsutum L.) as to production and quality of fiber relating to incident solar radiation. Incident solar radiation, as well as insolation during the trial period, were tabulated and compared with yelds and agricultural and technological characters of fibers. The treatment under cover showed a mean level of incident solar radiation equivalent to less than 20% of that at clear sky, causing a decrease in cotton production and in the agricultural and technological characters of fibers.

State-space approach to evaluate the relation between soil physical and chemical properties

The state-space approach is used to evaluate the relation between soil physical and chemical properties in an area cultivated with sugarcane. The experiment was carried out on a Rhodic Kandiudalf in Piracicaba, State of São Paulo, Brazil. Sugarcane was planted on an area of 0.21 ha i.e., in 15 rows 100 m long, spaced 1.4 m. Soil water content, soil organic matter, clay content and aggregate stability were sampled along a transect of 84 points, meter by meter. The state-space approach is used to evaluate how the soil water content is affected by itself and by soil organic matter, clay content, and aggregate stability of neighboring locations, in different combinations, aiming to contribute to a better understanding of the relation among these variables in the soil. Results show that soil water contents were successfully estimated by this approach. Best performances were found when the estimate of soil water content at locations i was related to soil water content, clay content and aggregate stability at locations i-1. Results also indicate that this state-space model using all series describes the soil water content better than any equivalent multiple regression equation.

Equivalent roughness of gravel-bed rivers

The relation between the equivalent roughness and different grain size percentiles of the sediment in gravel-bed rivers was determined under the hypothesis that the vertical distribution of the flow velocity follows a logarithmic law. A set of 954 data points was selected from rivers with gravel size sediment or larger, with a non-sinuous alignment and free of vegetation or obstacles. According to the results, the ks roughness is equivalent to approximately 2.4D90, 2.8D84, and 6.1D50. No correlation was detected between the sediment sorting and the sediment mobility index on one hand, and, on the other, the coefficient of proportionality of each grain size percentile.

Time motion analysis of football (soccer) referees during official matches in relation to the type of fluid consumed

The aim of the present study was to determine the effect of volume and composition of fluid replacement on the physical performance of male football referees. Ten referees were evaluated during three official matches. In one match the participants were asked to consume mineral water ad libitum, and in the others they consumed a pre-determined volume of mineral water or a carbohydrate electrolyte solution (6.4% carbohydrate and 22 mM Na+) equivalent to 1% of their baseline body mass (half before the match and half during the interval). Total water loss, sweat rate and match physiological performance were measured. When rehydrated ad libitum (pre-match and at half time) participants lost 1.97 ± 0.18% of their pre-match body mass (2.14 ± 0.19 L). This parameter was significantly reduced when they consumed a pre-determined volume of fluid. Sweat rate was significantly reduced when the referees ingested a pre-determined volume of a carbohydrate electrolyte solution, 0.72 ± 0.12 vs 1.16 ± 0.11 L/h ad libitum. The high percentage (74.1%) of movements at low speed (walking, jogging) observed when they ingested fluid ad libitum was significantly reduced to 71% with mineral water and to 69.9% with carbohydrate solution. An increase in percent movement expended in backward running was observed when they consumed a pre-determined volume of carbohydrate solution, 7.7 ± 0.5 vs 5.5 ± 0.5% ad libitum. The improved hydration status achieved with the carbohydrate electrolyte solution reduced the length of time spent in activities at low-speed movements and increased the time spent in activities demanding high-energy expenditure.

Analyse systématique de la relation entre l’exposition prénatale aux biphényles polychlorés et les effets neurodéveloppementaux et thyroïdiens chez l’enfant

Les biphényles polychlorés (BPC) sont des contaminants de l’environnement, omniprésents dans la chaîne alimentaire, qui ont une propension à la bioaccumulation dans le corps humain. Ils traversent la barrière placentaire et sont suspectés d’induire des altérations du développement mental ou moteur chez des enfants exposés aux BPC pendant la vie intrautérine. Ces effets s’expliqueraient notamment par la capacité des BPC à perturber l’homéostasie de la fonction thyroïdienne chez la femme enceinte ou le nouveau-né. Malgré le nombre considérable d’études épidémiologiques réalisées, la relation entre l’exposition prénatale aux BPC et les altérations du développement mental et moteur ou de la fonction thyroïdienne n’a pas encore été clairement établie ; d’une part, différents bioindicateurs de l’exposition ont été employés (différents congénères de BPC mesurés et différentes matrices biologiques ou unités de mesure) limitant la comparaison directe entre les études et, d’autre part, le lien de causalité entre les BPC et les effets ciblés n’a pas été vérifié avec des critères épidémiologiques reconnus. Cette étude a été réalisée afin d’analyser la relation « concentration biologique de BPC – effet » entre l'exposition aux BPC de la mère pendant la grossesse et le développement mental et moteur de l’enfant ainsi que les paramètres de la fonction thyroïdienne chez la femme enceinte et le nouveau-né à partir d’une analyse systématique des études épidémiologiques disponibles en standardisant les données biologiques entre les études. Sur la base de considérations toxicocinétiques et en appliquant des facteurs de conversion établis à partir de la littérature épidémiologique publiée, les concentrations des BPC rapportées dans les différentes études revues ont été standardisées en termes d’équivalent de BPC totaux par kilogramme de lipides dans le plasma maternel (µg PCBMPEQ/kg de lipides). Afin d’analyser la possibilité d’une association causale entre l’exposition aux BPC et les effets d’intérêt, les critères de Hill ont été appliqués systématiquement à l’ensemble des associations « concentrations biologiques standardisées – effet ciblés ». En appliquant cette approche aux données publiées de 20 études épidémiologiques sur la relation entre les BPC et le poids à la naissance, l’exposition prénatale aux BPC, aux niveaux décrits (moyenne < 1920 µg PCBMPEQ/kg de lipides), n’apparaît pas associée de manière significative à un poids à la naissance inférieur à 2500 g dans les populations étudiées. Par ailleurs, en considérant des études menées sur le suivi de neuf cohortes d’enfants, la probabilité qu’une altération cognitive ou motrice cliniquement significative, qui persiste entre la naissance et l’âge scolaire, soit observée à des concentrations de BPC totaux inférieures à 1000 µg PCBMPEQ/kg de lipides semble faible. Aussi, à partir de l’analyse systématique des données de 17 études épidémiologiques, l’exposition aux BPC aux niveaux standardisés décrits (moyenne < 1000 µg PCBMPEQ/kg de lipides) ne semble pas induire de variation des hormones thyroïdiennes ou de TSH en dehors des intervalles physiologiques reconnus chez la femme enceinte et le nouveau-né. Ainsi, la valeur biologique de référence établie à 1000 µg PCBMPEQ/kg de lipides pour prévenir les effets sur le développement devrait aussi prévenir les effets sur le poids à la naissance et la fonction thyroïdienne chez la femme enceinte ou le nouveau-né. Les résultats présentés dans cette thèse fournissent aux autorités de santé publique responsables de l’établissement de directives et des normes de l’information utile à la révision des critères sanitaires visant à protéger des effets des BPC sur le développement de l’enfant et la fonction thyroïdienne chez la femme enceinte et le nouveau-né.

Subterranean termites (Isoptera: Rhinotermitidae): Exploitation of equivalent food resources with different forms of placement

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Foraging in subterranean termites (Isoptera: Rhinotermitidae): how do Heterotermes tenuis and Coptotermes gestroi behave when they locate equivalent food resources?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aerial Rivers and Lakes: Looking at Large-Scale Moisture Transport and Its Relation to Amazonia and to Subtropical Rainfall in South America

This is an observational study of the large-scale moisture transport over South America, with some analyses on its relation to subtropical rainfall. The concept of aerial rivers is proposed as a framework: it is an analogy between the main pathways of moisture flow in the atmosphere and surface rivers. Opposite to surface rivers, aerial rivers gain (lose) water through evaporation (precipitation). The magnitude of the vertically integrated moisture transport is discharge, and precipitable water is like the mass of the liquid column-multiplied by an equivalent speed it gives discharge. Trade wind flow into Amazonia, and the north/northwesterly flow to the subtropics, east of the Andes, are aerial rivers. Aerial lakes are the sections of a moisture pathway where the flow slows down and broadens, because of diffluence, and becomes deeper, with higher precipitable water. This is the case over Amazonia, downstream of the trade wind confluence. In the dry season, moisture from the aerial lake is transported northeastward, but weaker flow over southern Amazonia heads southward toward the subtropics. Southern Amazonia appears as a source of moisture to this flow. Aerial river discharge to the subtropics is comparable to that of the Amazon River. The variations of the amount of moisture coming from Amazonia have an important effect over the variability of discharge. Correlations between the flow from Amazonia and subtropical rainfall are not strong. However, some months within the set of dry seasons observed showed a strong increase (decrease) occurring together with an important increase (decrease) in subtropical rainfall.

Steady-state function of the ubiquitous mammalian Na/H exchanger (NHE1) in relation to dimer coupling models with 2Na/2H stoichiometry

We describe the steady-state function of the ubiquitous mammalian Na/H exchanger (NHE)1 isoform in voltage-clamped Chinese hamster ovary cells, as well as other cells, using oscillating pH-sensitive microelectrodes to quantify proton fluxes via extracellular pH gradients. Giant excised patches could not be used as gigaseal formation disrupts NHE activity within the patch. We first analyzed forward transport at an extracellular pH of 8.2 with no cytoplasmic Na (i.e., nearly zero-trans). The extracellular Na concentration dependence is sigmoidal at a cytoplasmic pH of 6.8 with a Hill coefficient of 1.8. In contrast, at a cytoplasmic pH of 6.0, the Hill coefficient is <1, and Na dependence often appears biphasic. Results are similar for mouse skin fibroblasts and for an opossum kidney cell line that expresses the NHE3 isoform, whereas NHE1(-/-) skin fibroblasts generate no proton fluxes in equivalent experiments. As proton flux is decreased by increasing cytoplasmic pH, the half-maximal concentration (K(1/2)) of extracellular Na decreases less than expected for simple consecutive ion exchange models. The K(1/2) for cytoplasmic protons decreases with increasing extracellular Na, opposite to predictions of consecutive exchange models. For reverse transport, which is robust at a cytoplasmic pH of 7.6, the K(1/2) for extracellular protons decreases only a factor of 0.4 when maximal activity is decreased fivefold by reducing cytoplasmic Na. With 140 mM of extracellular Na and no cytoplasmic Na, the K(1/2) for cytoplasmic protons is 50 nM (pH 7.3; Hill coefficient, 1.5), and activity decreases only 25% with extracellular acidification from 8.5 to 7.2. Most data can be reconstructed with two very different coupled dimer models. In one model, monomers operate independently at low cytoplasmic pH but couple to translocate two ions in "parallel" at alkaline pH. In the second "serial" model, each monomer transports two ions, and translocation by one monomer allosterically promotes translocation by the paired monomer in opposite direction. We conclude that a large fraction of mammalian Na/H activity may occur with a 2Na/2H stoichiometry.

Atmospheric parameters, spectral indexes and their relation to CPV spectral performance

Air Mass and atmosphere components (basically aerosol (AOD) and precipitable water (PW)) define the absorption of the sunlight that arrive to Earth. Radiative models such as SMARTS or MODTRAN use these parameters to generate an equivalent spectrum. However, complex and expensive instruments (as AERONET network devices) are needed to obtain AOD and PW. On the other hand, the use of isotype cells is a convenient way to characterize spectrally a place for CPV considering that they provide the photocurrent of the different internal subcells individually. Crossing data from AERONET station and a Tri-band Spectroheliometer, a model that correlates Spectral Mismatch Ratios and atmospheric parameters is proposed. Considering the amount of stations of AERONET network, this model may be used to estimate the spectral influence on energy performance of CPV systems close to all the stations worldwide.