Controle patrimonial (ativo imobilizado) da Embrapa Florestas.

bitstream/item/25618/1/165-10.pd

Even-odd effects in the electrical conductance of a three terminals device composed by linear chains: an analytical approach

"Available online 6 May 2022"In this work we propose a theoretical study of odd-even effects in charge transport through a linear three terminal chain device. We use the Landauer approach, with the electronic structure treated at tight binding (TB) level and model the self-energy as an energy independent parameter. Moreover, we use decimation techniques to renormalize the system, reducing it into a 3 × 3 matrix, so as to make an analytical treatment. By varying the size of the chain, we alter not only the parity of the full system but also the parity of each possible pathway and show how odd-even effect appears in the transmission function, local density of states and the behavior of the electrical current as function of the parity. Our theoretical approach reveals, in a clear way, how the parity of each branch competes with the parity of the full system to the conductance values near the Fermi level.This research was carried out with financial support from Federal University of Pernambuco (Brazil). L. Marques acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and projects SATRAP (POCI-01-0145-FEDER-028108), SATRAP+( EXPL/FIS-MAC/0947/2021). The authors also acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing access to STAMPEDE2 - HPC resources that have contributed to the research results reported within this paper

Double versus single junction: from tunneling to contact regime in a double quantum dot molecule system

In this work a theoretical study of the charge transport through a nanostructure composed by a double quantum dot was made by treating the system in two different ways: as single junction (SJ) within the scanning tunneling microscopy theory and a double junction (DJ) within the usual non equilibrium Green's function theory approach. In the first case (SJ), the three blocks - contact-device-contact - is treated as a single junction by 'breaking' the nanostructure into two parts and considering each one as belonging to an 'extended contact'. In the DJ case, the usual treatment with two contacts-related broadening and the exact Green's function describing the propagation inside the system was made. Proceeding in this way, for a minimum two-level model system, we show that the results obtained with the SJ and DJ treatment are identical despite they start with a different general formulae for transmission. Finally, both treatments were used with a minimal model for a biphenyl system in an asymmetric sample-biphenyl-tip configuration and analyzed in terms of a SJ point of view bringing another perspective to the main features of this system.This research was carried out with financial support from Federal University of Pernambuco (Brazil) . L. Marques acknowledges the financial support of the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and project SATRAP (POCI010145FEDER028108)

Science-religion dialogue in education: religion teachers’ perceptions in a roman-catholic context

This paper examines the relationship between science and religion in the education system of Roman-Catholic Portuguese society. In particular, we explored perceptions of the relationship between science and religion for religious education teachers. We surveyed 198 Portuguese religious education teachers about how they view science and religion. The questionnaires’ results revealed a number of similarities: religious education teachers are highly involved in religious practices and exposed to science; they perceived a compatibility between science and religion; and they have an openness to dialogue between both. They do not adhere to anti-scientific perspectives, but they simultaneously try to limit what can be explained by science. Thus, an interpretative view of dialogue and/or integration seems to best explain the perceptions of religious education teachers of the relationship between science and religion. These findings allow a space of discussion, enabling teachers to possibly foster the science-religion dialogue in their contexts of pedagogical activity.info:eu-repo/semantics/acceptedVersio

Influência do estado nutricional na cianogênese de clones de copa de seringueira.

A determinação do potencial cianogênico (HCNp) em folhas jovens de clones de copa de seringueira mostrou uma grande variação nos valores de amostras de indivíduos de mesmo clone plantados em áreas distintas. Para constatar a possível influência do estado nutricional na formação dos glicosídios cianogênicos foram feitas correlações entre os teores foliares de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn e o HCNp determinado nas folhas jovens dos clones de copa CPAA C 01 e CPAA C 81. Dos nutrientes analisados, foram verificadas interações significativas apenas com os teores de nitrogênio e manganês

Alterações na rizosfera em resposta a aplicação de glifosato e zinco na soja.

O objetivo deste trabalho foi verificar os efeito da aplicação de glifosato na absorção de zinco (Zn) na rizosfera. O experimento foi realizado em casa de vegetação com caixa tipo ?Tetra Pak?, revestidas externamente com papel alumínio, contendo 1,2 quilos do Neossolo Quartzarênico órtico. Os tratamentos consistiram de duas doses de Zn (0 e 5 mg kg-1 - fonte: ZnSO4×7H2O) e duas cultivares parentais (BRS 133 e BRS 245RR), sendo que a última foi também dividida em dois tratamentos: com e sem glifosato (Roundup Ready®). Foram determinados a produção de matéria seca, teores de Zn2+ disponível e H+ trocável fora e dentro da rizosfera, teor total de Zn nas folhas (R1) e raízes. Os resultados mostram que a aplicação de glifosato interfere na rizosfera diminuindo a absorção de Zn pelas plantas

Electronic transport through odd-even methylenic spacers connected to an aromatic ring

In this work we propose a theoretical study of charge transport through a nanostructure composed by a methylenic bridge with a phenyl ring at the end, attached between a small silicon cluster in the bottom and a small lead cluster at the top. We use the Non Equilibrium Green Function theory (NEGF-theory) approach, with the electronic structure treated at the density functional theory (DFT) level and model the self energy with the wide band limit approximation. By varying the size of the methylenic bridge from two to five carbons, we show that a geometrical odd–even effect appears in charge transport for cryogenic temperatures, while it is suppressed at room temperature. Such phenomenon was studied by combining MD simulations with ab-initio NEGF transport calculations, thus accounting for the thermal effects. Our theoretical approach reveals the role of avoided-crossing effect on system conductance, occurring only for some alkyl bridge lengths.FCT - Fundação para a Ciência e a Tecnologia(CPCA/A2/4628/2020)This research was carried out with financial support from Federal University of Pernambuco (Brazil). L. Marques acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and projects SATRAP (POCI-01-0145-FEDER-028108), Control-LUB (UTAP-EXPL/NTec/0107/2017) and Advanced Computing Project CPCA /A2/4628/2020for access to Oblivion HPC resources