Neuromorphometric characterization with shape functionals

This work presents a procedure to extract morphological information from neuronal cells based on the variation of shape functionals as the cell geometry undergoes a dilation through a wide interval of spatial scales. The targeted shapes are alpha and beta cat retinal ganglion cells, which are characterized by different ranges of dendritic field diameter. Image functionals are expected to act as descriptors of the shape, gathering relevant geometric and topological features of the complex cell form. We present a comparative study of classification performance of additive shape descriptors, namely, Minkowski functionals, and the nonadditive multiscale fractal. We found that the proposed measures perform efficiently the task of identifying the two main classes alpha and beta based solely on scale invariant information, while also providing intraclass morphological assessment

Danos de gafanhotos (Orthoptera, Acrididae, Leptysminae) em reflorestamentos no Estado do Pará.

bitstream/item/27899/1/Com.Tec.206.pdfDisponível também on-line

The Spectroscopic Age of 47 Tuc

High signal-to-noise integrated spectra of the metal-rich globular cluster 47 Tuc, spanning the H-gamma(HR) and Fe4668 line indices, have been obtained. The combination of these indices has been suggested (Jones & Worthey 1995, ApJ, 446, L31) as the best available mechanism for cleanly separating the age-metallicity degeneracy which hampers the dating of distant, unresolved, elliptical galaxies. For the first time, we apply this technique to a nearby spheroidal system, 47 Tuc, for which independent ages, based upon more established methods, exist. Such an independent test of the technique's suitability has not been attempted before, but is an essential one before its application to more distant, unresolved, stellar populations can be considered valid. Because of its weak series of Balmer lines, relative to model spectra, our results imply a spectroscopic ``age'' for 47 Tuc well in excess of 20 Gyr, at odds with the colour-magnitude diagram age of 14+/-1 Gyr. The derived metal abundance, however, is consistent with the known value. Emission ``fill-in'' of the H-gamma line as the source of the discrepancy cannot be entirely excluded by existing data, although the observational constraints are restrictive.Comment: 17 pages, 4 figures, LaTeX, accepted for publication in The Astronomical Journal, also available at http://casa.colorado.edu/~bgibson/publications.htm

Chattering-free sliding mode control with a fuzzy model for structural applications

This paper proposes a chattering-free sliding mode control (CFSMC) method for seismically excited structures. The method is based on a fuzzy logic (FL) model applied to smooth the control force and eliminate chattering, where the switching part of the control law is replaced by an FL output. The CFSMC is robust and keeps the advantages of the conventional sliding mode control (SMC), whilst removing the chattering and avoiding the time-consuming process of generating fuzzy rule basis. The proposed method is tested on an 8-story shear frame equipped with an active tendon system. Results indicate that the new method not only can effectively enhance the seismic performance of the structural system compared to the SMC, but also ensure system stability and high accuracy with less computational cost. The CFSMC also requires less amount of energy from the active tendon system to produce the desired structural dynamic response.ARC DE150101703 and ARC LP14010059

Seca do frutos do açaizeiro no estado do Pará.

Objetivou-se relatar a seca dos frutos do açaizeiro, em três diferentes municípios do estado do Pará, safra 2014. Amostras de frutos secos dos municípios de Abaetetuba e Belém foram analisadas no Laboratório de Fitopatologia da Embrapa Amazônia Oriental e do município de Igarapé Mirim no Laboratório de Microbiologia de Alimentos do IFPA - Campus Castanhal, respectivamente. Os frutos foram incubados em caixas do tipo 'gerbox' à temperatura de 25±2 ºC e fotoperíodo de 12h, durante até 72h. Procederam-se isolamentos diretos em placas de Petri com meio de cultura ágar-água a 20%. Frutos com esporulação do patógeno foram utilizados para o isolamento direto, sem incubação prévia, e analisados em microscópios estereoscópio e de luz. Após três dias de incubação, discos de micélios foram repicados para o meio de cultura batata dextrose ágar (BDA). Observaram-se crescimento micelial branco e, após 10 dias de incubação, verificou-se a formação de colônias de coloração acinzentada nas placas de Petri. Foram confeccionadas lâminas para microscopia de luz. Verificaram-se a presença de hifas septadas e ramificadas e intensa produção de conídios unicelulares hialinos, em ambas as amostras. A doença seca dos frutos foi confirmada em amostras oriundas dos municípios de Abaetetuba, Belém e Igarapé Mirim, com associação do fungo Colletotrichum spp

Avoided crossings in mesoscopic systems: electron propagation on a non-uniform magnetic cylinder

We consider an electron constrained to move on a surface with revolution symmetry in the presence of a constant magnetic field $B$ parallel to the surface axis. Depending on $B$ and the surface geometry the transverse part of the spectrum typically exhibits many crossings which change to avoided crossings if a weak symmetry breaking interaction is introduced. We study the effect of such perturbations on the quantum propagation. This problem admits a natural reformulation to which tools from molecular dynamics can be applied. In turn, this leads to the study of a perturbation theory for the time dependent Born-Oppenheimer approximation

Avaliação fenológica da espécie Carapa guianensis Aubl.

A espécie Carapa guianensis Aubl., conhecida popularmente na região amazônica como andiroba é muita utilizada na medicina tradicional, na indústria farmacêutica, cosmética e como recurso madeireiro. É de extrema importância o estudo das fenofases dessa espécie, pois servirá como apoio a gestão deste recurso natural, como para a coleta de sementes para a extração do óleo da andiroba. O objetivo deste estudo foi de avaliar o período de floração e frutificação da Carapa guianenses Aubl., correlacionando com a precipitação pluviométrica visando identificar a época mais adequada para a coleta e utilização das sementes desta espécie. Foram avaliados sete indivíduos diariamente no período de janeiro de 2012 á dezembro de 2016 conservados no horto de plantas medicinais da Embrapa Amazônia Oriental e registrado a quantidade de dias de floração e frutificação. Ocorreu floração e frutificação em todos os meses do ano. A maior média de número (18,8) de dias de floração e frutificação foi registrada no mês de maio e uma precipitação pluviométrica em torno de 271 mm. A menor média (7,8) de número de dias de floração ocorreu no mês de julho e a menor média de número de dias de frutificação foi registrada no mês de outubro com 2,4 dias quando foi registrada a menor média (60,18 mm) de pluviometria. Os resultados demonstraram que a precipitação pluviométrica influenciou o número de dias de ocorrência das fenofases e a coleta para uso das sementes pode ser realizada em todos os meses do ano

FISH DIVERSITY ALONG THE LONGITUDINAL GRADIENT IN A MAN–MADE LAKE OF WEST AFRICA, TAABO HYDROELECTRIC RESERVOIR, IVORY COAST

Fish assemblage patterns in Taabo Reservoir, a hydroelectric lake of Ivory Coast, were studied and related to the longitudinal gradient (river–dam gradient) composed of riverine, transitional, and lacustrine zones. Data were collected at 5 stations and each one was sampled during 5 surveys. Fish community structure was analysed using alpha and beta diversity indices. In total, 53 fish species were obtained in the whole ecosystem. Total species richness recorded at each ecological zone was 42, 43 and 45 species respectively in the riverine, transitional and lacustrine zones. Alpha diversity did not differed significantly along the longitudinal gradient but reached the highest value (33 species) in the transitional zone and the lowest (18 species) occurred in both the riverine and lacustrine zones. Temporal variability of Alpha diversity according to the hydrological regime of the lake differed with the zone. Beta diversity showed that fish assemblages similarity was higher between the transitional and the riverine zones (βw = 0.43) and lower between the riverine and the lacustrine zones (βw = 0.79)