Rigidez dos triângulos

Pós-graduação em Matemática em Rede Nacional - IBILCE

A pipa tetraédrica de Graham Bell: abordagem em sala de aula como elemento motivador da aprendizagem

Pós-graduação em Matemática em Rede Nacional - IBILCE

Figuras fulgurantes: a geometrização do espaço Llansol

Os pregos na erva (1962), the first book by Maria Gabriela Llansol, presents us several textures and pictures that break the dividing lines of both textual and imaging spaces due to the figurative compositional process that stands within the literary universe, coloring it with words. The short stories found in this book are based on minimum action that silences the voices of the characters, expanding some other composition, a new course, not in the order of the narrative continuum, but of the textual one. The three short stories to be analyzed (“Intróito”, “A casa às avessas” e “A manhã morta”) are highlighted due to the meaningful incidence of poetic colors that set representation and the motionless universe of narrative on the move, due to the dialogue established with painting, especially with the pictures by Amadeo Modigliani (“Young Brunette”) and Picasso (“Child holding a dove”). Thus, the lines of writing and the geometric ones of painting cross with each other and draft triangles and circles, being responsible for figures that go beyond figurative language and, by doing so, making the suggested images of textuality’s “fulgor” stronger.

Orange pectin mediated growth and stability of aqueous gold and silver nanocolloids

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

Breeding season diet of Scarlet Ibises and Little Blue Herons in a Brazilian mangrove swamp

We studied the diet composition and overlap of Scarlet Ibises (Eudocimus ruber) and Little Blue Herons (Egretta caerulea in a mangrove swamp in southeast Brazil during the 1996-1997 breeding season, which occurs during the rainiest period. Crabs comprised 95% of all prey taken by the ibises and 80% of the prey of the herons, Nevertheless, diet overlap was small (similar to 30%) due to ibises feeding mostly on Uca spp. and Eurythium limosum crabs, which were taken from their burrows; the herons fed on the arboreal and semi-arboreal Aratus Pisonii and Metasesarma rubripes crabs. Divergent hunting strategies of ibises (tactile foragers) and herons visually-oriented predators) explains the diet segregation when preying on an ecologically diverse crab guild, but it is unclear why herons prey rarely on fiddler crabs. Scarlet Ibises bred successfully while feeding oil estuarine organisms living in low salinities in the mangroves, showing that mangroves may be adequate foraging habitats for chick-rearing ibises during periods of low salinity.

Algumas potencialidades didáticas do setor trigonal na interface entre história e ensino de matemática

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O Ensino de Geometria por meio de atividades investigativas: uma experiência com alunos do primeiro ano do Ensino Médio

This qualitative nature of work was developed with the participation of a group of students enrolled in the first year of high school from a public school of the state of São Paulo, in the city of Taubaté. Their goal was to determine how students deal with geometry tasks in investigative classes. To guide this research was drawn up the following question: As students of the first year of high school express their knowledge of building triangles and quads in classes of investigative activities?. The choice of investigative nature of this activity occurred by enhancing student participation and thus generate a greater chance of it not be guided only by what the teacher wants, but by his own curiosity and using their own tools for this. In the data analysis process stands out the interest generated in students for this type of activity and posture maintained throughout the work, mobilizing their expertise to answer the questions posed

Avian Piscivores as Vectors for Myxobolus cerebralis in the Greater Yellowstone Ecosystem

Myxobolus cerebralis, the cause of whirling disease in salmonids, has dispersed to waters in 25 states within the USA, often by an unknown vector. Its incidence in Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri within the highly protected environment of Yellowstone Lake, Yellowstone National Park, is a prime example. Given the local abundances of piscivorous birds, we sought to clarify their potential role in the dissemination of M. cerebralis. Six individuals from each of three bird species (American white pelican Pelecanus erythrorhynchos, double-crested cormorant Phalacrocorax auritus, and great blue heron Ardea herodias) were fed known-infected or uninfected rainbow trout O. mykiss. Fecal material produced during 10-d periods before and after feeding was collected to determine whether M. cerebralis could be detected and, if so, whether it remained viable after passage through the gastrointestinal tract of these birds. For all (100%) of the nine birds fed known-infected fish, fecal samples collected during days 1–4 after feeding tested positive for M. cerebralis by polymerase chain reaction. In addition, tubificid worms Tubifex tubifex that were fed fecal material from known-infected great blue herons produced triactinomyxons in laboratory cultures, confirming the persistent viability of the parasite. No triactinomyxons were produced from T. tubifex fed fecal material from known-infected American white pelicans or double-crested cormorants, indicating a potential loss of parasite viability in these species. Great blue herons have the ability to concentrate and release viable myxospores into shallow-water habitats that are highly suitable for T. tubifex, thereby supporting a positive feedback loop in which the proliferation of M. cerebralis is enhanced. The presence of avian piscivores as an important component of aquatic ecosystems should continue to be supported. However, given the distances traveled by great blue herons between rookeries and foraging areas in just days, any practices that unnaturally attract them may heighten the probability of M. cerebralis dispersal and proliferation within the Greater Yellowstone Ecosystem.

O Ensino de Geometria por meio de atividades investigativas: uma experiência com alunos do primeiro ano do Ensino Médio

This qualitative nature of work was developed with the participation of a group of students enrolled in the first year of high school from a public school of the state of São Paulo, in the city of Taubaté. Their goal was to determine how students deal with geometry tasks in investigative classes. To guide this research was drawn up the following question: As students of the first year of high school express their knowledge of building triangles and quads in classes of investigative activities?. The choice of investigative nature of this activity occurred by enhancing student participation and thus generate a greater chance of it not be guided only by what the teacher wants, but by his own curiosity and using their own tools for this. In the data analysis process stands out the interest generated in students for this type of activity and posture maintained throughout the work, mobilizing their expertise to answer the questions posed

Tracing latitudinal gradient, river discharge and water masses along the Subtropical South American Coast using benthic Foraminifera assemblages

More than 30% of Buccella peruviana (D'Orbigny), Globocassidulina crassa porrecta (Earland & Heron-Allen), Cibicides mackannai (Galloway & Wissler) and C. refulgens (Montfort) indicate the presence of cold Sub Antarctic Shelf Water in winter, from 33.5 to 38.3 degrees S, deeper than 100 m, in the southern part of the study area. In summer, the abundance of this association decreases to less than 15% around 37.5-38.9 degrees S where two species (Globocassidulina subglobosa (Brady), Uvigerina peregrina (Cushman) take over. G. subglobosa, U. peregrina, and Hanzawaia boueana (D'Orbigny) are found at 27-33 degrees S in both seasons in less than 55 m deep in the northern part, and are linked with warm Subtropical Shelf Water and Tropical Water. Freshwater influence was signalized by high silicate concentration and by the presence of Pseudononion atlanticum (Cushman), Bolivina striatula (Cushman), Buliminella elegantissima (D'Orbigny), Bulimina elongata (D'Orbigny), Elphidium excavatum (Terquem), E. poeyanum (D'Orbigny), Ammobaculites exiguus (Cushman & Bronnimann), Arenoparrella mexicana (Kornfeld), Gaudryina exillis (Cushman & Bronnimann), Textularia earlandi (Parker) and thecamoebians in four sectors of the shelf. The presence of Bulimina marginata (D'Orbigny) between 34.1-32.8 degrees S in the winter and 34.2-32.7 degrees S in the summer indicates that the influence of the Subtropical Shelf Front on the sediment does not change seasonally, otherwise, the presence of Angulogerina angulosa (Williamson) in the winter, only in Mar del Plata (38.9 degrees S), show that Malvinas currents are not influencing the sediment in the summer.

Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures.

Tracing latitudinal gradient, river discharge and water masses along the subtropical South American coast using benthic Foraminifera assemblages

More than 30% of Buccella peruviana (D'Orbigny), Globocassidulina crassa porrecta (Earland & Heron-Allen), Cibicides mackannai (Galloway & Wissler) and C. refulgens (Montfort) indicate the presence of cold Sub Antarctic Shelf Water in winter, from 33.5 to 38.3º S, deeper than 100 m, in the southern part of the study area. In summer, the abundance of this association decreases to less than 15% around 37.5-38.9º S where two species (Globocassidulina subglobosa (Brady), Uvigerina peregrina (Cushman) take over. G. subglobosa, U. peregrina, and Hanzawaia boueana (D'Orbigny) are found at 27-33º S in both seasons in less than 55 m deep in the northern part, and are linked with warm Subtropical Shelf Water and Tropical Water. Freshwater influence was signalized by high silicate concentration and by the presence of Pseudononion atlanticum (Cushman), Bolivina striatula (Cushman), Buliminella elegantissima (D'Orbigny), Bulimina elongata (D'Orbigny), Elphidium excavatum (Terquem), E. poeyanum (D'Orbigny), Ammobaculites exiguus (Cushman & Brönnimann), Arenoparrella mexicana (Kornfeld), Gaudryina exillis (Cushman & Brönnimann), Textularia earlandi (Parker) and thecamoebians in four sectors of the shelf. The presence of Bulimina marginata (D'Orbigny) between 34.1-32.8º S in the winter and 34.2-32.7º S in the summer indicates that the influence of the Subtropical Shelf Front on the sediment does not change seasonally, otherwise, the presence of Angulogerina angulosa (Williamson) in the winter, only in Mar del Plata (38.9º S), show that Malvinas currents are not influencing the sediment in the summer.

An adaptive solar radiation numerical model

[EN]A numerical model for the evaluation of solar radiation in different locations is presented. The solar radiation model is implemented taking into account the terrain surface using two-dimensional adaptive meshes of triangles that are constructed using a refinement/derefinement procedure in accordance with the variations of terrain surface and albedo. The selected methodology defines the terrain characteristics with a minimum number of points so that the computational cost is reduced for a given accuracy. The model can be used in atmospheric sciences as well as in other fields such as electrical engineering, since it allows the user to find the optimal location for maximum power generation in photovoltaic or solar thermal power plants...

Multithread parallelization of lepp-bisection algorithms

[EN]Longest edge (nested) algorithms for triangulation refinement in two dimensions are able to produce hierarchies of quality and nested irregular triangulations as needed both for adaptive finite element methods and for multigrid methods. They can be formulated in terms of the longest edge propagation path (Lepp) and terminal edge concepts, to refine the target triangles and some related neighbors. We discuss a parallel multithread algorithm, where every thread is in charge of refining a triangle t and its associated Lepp neighbors. The thread manages a changing Lepp(t) (ordered set of increasing triangles) both to find a last longest (terminal) edge and to refine the pair of triangles sharing this edge...

Solar radiation estimation using a numerical model

[EN]A solar radiation numerical model is presented. It is intented to be useful for different purposes like the evaluation of the suitability of possible locations for solar power stations. This model allows the user to evaluate the radiation values in any location easily, and estimate the solar power generation taking into account not only the radiation level, but also the terrain surface conditions considering the cast shadows. The solar radiation model is implemented taking into account the terrain surface using 2-D adaptive meshes of triangles, which are constructed using a refinement/derefinement procedure in accordance with the variations of terrain surface and albedo...