Recording from two neurons: second order stimulus reconstruction from spike trains and population coding

We study the reconstruction of visual stimuli from spike trains, recording simultaneously from the two H1 neurons located in the lobula plate of the fly Chrysomya megacephala. The fly views two types of stimuli, corresponding to rotational and translational displacements. If the reconstructed stimulus is to be represented by a Volterra series and correlations between spikes are to be taken into account, first order expansions are insufficient and we have to go to second order, at least. In this case higher order correlation functions have to be manipulated, whose size may become prohibitively large. We therefore develop a Gaussian-like representation for fourth order correlation functions, which works exceedingly well in the case of the fly. The reconstructions using this Gaussian-like representation are very similar to the reconstructions using the experimental correlation functions. The overall contribution to rotational stimulus reconstruction of the second order kernels - measured by a chi-squared averaged over the whole experiment - is only about 8% of the first order contribution. Yet if we introduce an instant-dependent chi-square to measure the contribution of second order kernels at special events, we observe an up to 100% improvement. As may be expected, for translational stimuli the reconstructions are rather poor. The Gaussian-like representation could be a valuable aid in population coding with large number of neurons

Análise de solos: finalidade e procedimentos de amostragem.

A análise de solos é o único método que permite, antes do plantio, conhecer a capacidade de um determinado solo suprir nutrientes para as plantas. É a forma mais simples, econômica e eficiente de diagnose da fertilidade das terras e constitui base imprescindível para a recomendação de quantidades adequadas de corretivos e fertilizantes para aumentar a produtividade das culturas e, como consequência a produção e a lucratividade das lavouras.bitstream/CPAP-2010/57309/1/COT79.pd

Soil carbon and nitrogen stocks under natural forested savannah and cultivated pasture in the Pantanal, Mato Grosso do Sul, Brazil.

The goal of this study was to estimate the soil C and N stocks under Urochloa spp.pasture with a natural forested savannah as a reference.(Embrapa Gado de Corte. Documentos, 216). Coordenador Roberto Giolo de Almeida. II SIGEE. Disponível em: . Acesso em: 30 nov. 2016

Comparison of nonlinear growth models and factors affecting body weight at different ages in Toy Poodles

Limited information is available to evaluate optimal growth in Toy Poodles. This work aimed at comparing three growth curves, proposing centile charts and developing a model to estimate the adult body weight (BW) in Toy Poodles. A total of 65 puppies (male = 30, female = 35) born in the same breeding centre were used. BW at birth and, weekly BW, for 53 weeks, BW of parents, litter size, type of management, daily activity and neutering were recorded. Forty-six puppies were sold, and their data were reported by the new owners. Three growth curves (i.e. Hawthorne, Brody and Gompertz) were constructed and compared; Linear Mixed Models including demographic characteristics and management habits were built. The BW at birth was 154 \ub1 35 g and adult BW was 3208 \ub1 860 g. Based on the goodness-of-fit and accuracy indices, Gompertz was the best growth model and was selected to plot centile curves based on sex. Toy Poodles achieved 50% of their adult weight at 11\u201312 weeks, with an overall growth rate of 11.8%. Adult BW was affected by birth BW (p <.01), sex (p <.05) and mother\u2019s BW (p <.01) and their effects varied depending on the age. Extrinsic factors, including litter size, type of management and daily activity were less significant, probably due to the standardised and high-level management of these Toy Poodles. These new and applicable tools for monitoring the growth and predicting adult BW could be useful for veterinarians, breeders and owners for early diagnosis of poor health and welfare. Subject classification codes: companion animals sectionsHighlights Performance of three logistic models for describing the growth curve in Italian Toy Poodles were compared Based on the goodness of fit and accuracy indices, Gompertz was the best growth model The centile growth curves were constructed for males and females using the Gompertz Adult body weight (BW) was mainly affected by the sex and birth BW, and less by BW of the parents and litter size Monitoring BW of puppies may be useful to enhance their health and welfare

Avaliação de Cleruchoides noackae em Laboratório e Campo em Minas Gerais, Brasil.

Resumo

Environmental Governance in the Insertion of Electric Mobility in the Fernando of Noronha Archipelago (Brazil, Pernambuco)

Climate change is a topic that has been gaining importance in global discussions In addition to industries automobiles release greenhouse gases GHG into the atmosphere that act directly on the increase of the greenhouse effect and consequently on the increase in the temperature of the globe which requires measures to minimize their effects on the atmosphere The island of Fernando de Noronha has been used as a model for the implementation of electric mobility Law n 16 810 2020 establishes that until 2030 combustion cars will no longer be allowed to enter the island being replaced by electric cars Solar electric mobility has been gradually taking place in this territory and with conflicts on the part of those interested who use vehicles as a means of subsistence on the island This research aimed to analyze how environmental governance was carried out in the process of inserting electric mobility on the island of Fernando de Noronha PE through bibliographical and documentary research interviews and observation In view of the results it was observed in the environmental governance of the electric mobility insertion process that only three principles of environmental governance were identified within this territory decentralization transparency and security leaving the other principles behin

Produtividade de braquiarias na sub-regiao da Nhecolandia, Pantanal, MS - Brasil.

O Pantanal, essa imensa planicie sedimentar, de aproximadamente 140.000 km2, possui como um dos pilares da economia a exploracao da bovinocultura de corte. O regime de criacao e do tipo extensivo, concentrada principalmente na atividade de cria. Dentre as sub-regioes do Pantanal, a Nhecolandia e uma das maiores em termos de area e onde esta concentrado o maior rebanho bovino. Os solos sao essencialmente arenosos, apresentando a vegetacao natural em quatro unidades geomorficas: "cerradao ou mata", "caronal, predominacia do capim carona - Elyonurus muticus, "campo-cerrado" e "vazante", essas divisoes sao determinadas pelo nivel de fertilidade do solo, nivel e duracao das enchentes. A precipitacao pluvial anual esta em torno de 1.000 a 1.400 mm. A alimentacao do rebanho bovino baseava-se exclusivamente em pastagem nativa. Entretanto, como alternativa para o aumento da produtividade, ha cerca de duas decadas vem sendo efetuada a formacao de pastagens, com a introducao de gramineas exoticas, inicialmente em areas de cerradao e cerrado e mais recentemente em campo de caronal, visando aumentar a oferta alimentar aos animais em epocas criticas. Destaca-se basicamente a introducao de Brachiarias decumbens e B. humidicola.bitstream/item/41118/1/PA17.pd

Carbon and nitrogen stocks in soil under different landscape units at the Pantanal ecosystem, Mato Grosso do Sul, Brazil.

This study aimed to evaluate the soil carbon and nitrogen storage under different landscape units in the Pantanal ecosystem.(Embrapa Gado de Corte. Documentos, 216). Coordenador Roberto Giolo de Almeida. II SIGEE. Disponível em: . Acesso em: 30 nov. 2016

Magnetic reconfiguration of MnAs/GaAs(001) observed by Magnetic Force Microscopy and Resonant Soft X-ray Scattering

We investigated the thermal evolution of the magnetic properties of MnAs epitaxial films grown on GaAs(001) during the coexistence of hexagonal/orthorhombic phases using polarized resonant (magnetic) soft X-ray scattering and magnetic force microscopy. The results of the diffuse satellite X-ray peaks were compared to those obtained by magnetic force microscopy and suggest a reorientation of ferromagnetic terraces as temperature rises. By measuring hysteresis loops at these peaks we show that this reorientation is common to all ferromagnetic terraces. The reorientation is explained by a simple model based on the shape anisotropy energy. Demagnetizing factors were calculated for different configurations suggested by the magnetic images. We noted that the magnetic moments flip from an in-plane mono-domain orientation at lower temperatures to a three-domain out-of-plane configuration at higher temperatures. The transition was observed when the ferromagnetic stripe width L is equal to 2.9 times the film thickness d. This is in good agreement with the expected theoretical value of L = 2.6d.Comment: 16 pages in PD