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)

Physical performance changes during circuit training and detraining in U15 soccer players

On-field soccer conditioning programs are effective to improve physical performance in soccer players. However, the effects of an in-season soccer-specific circuit during regular soccer training is still limited. Thus, this study aimed to analyse the effects of a soccer-specific circuit, followed by 4-weeks of detraining on physical performance in U15 soccer players. Twenty participants (13.3 ± 0.5 years) were involved in this study. A soccer-specific circuit (~15-min) performed without ball was applied three times per week and included sprints, changes of direction, jumps and skipping’s. Before and after 6-weeks, as well as after detraining, the outcome measures included: countermovement jump, repeated sprint ability, yo-yo intermittent recovery test level 1, change of direction and the 300-m modified shuttle-run test. After 6-weeks, repeated measures ANOVA revealed significant gains (p < .05) in almost variables, except for the percent sprint decrement in the repeated sprint ability test. After detraining, significant decreases (p < .05) were observed in almost variables, except for the countermovement jump best height and the repeated sprint ability best time. The results demonstrated that an in-season soccer-specific circuit was effective to improve physical performance in U15 soccer players. Nonetheless, 4-weeks of detraining is enough to revert the positive training-induced adaptations.This work was supported by a grant from the Portuguese Foundation for Science and Technology, I.P. (SFRH/BD/147608/2019)

Valoração econômica dos efeitos da erosão: estudo de caso em bacias hidrográficas.

O presente trabalho objetiva a mensuração econômica dos efeitos internos à área de produção causados pelo processo de erosão do solo, a partir do custo de reposição dos nutrientes perdidos pelo solo agrícola verificadas nas bacias hidrográficas dos Rios Atibaia e Jaguarí. Os valores econômicos podem vir a subsidiar a formulação de políticas públicas que visem não somente o controle da erosão do solo agrícola, mas também a melhoria da qualidade ambiental, expressa neste caso, pela qualidade dos recursos hídricos.1 Não ignorando as demais implicações extrínsecas à área agrícola, tomou-se os efeitos da erosão nas Bacias dos Rios Atibaia e Jaguarí como um estudo de caso, onde foi exercitado o princípio da determinação do valor econômico do ambiente, por meio do método, chamado de custo de reposição. Assim, foi possível estimar o chamado valor de uso. Os outros componentes do valor econômico total do ambiente, os valores de opção, de existência e os demais valores de uso, também poderiam ser estimados, no entanto não se constituiu objetivo do presente trabalho. A partir desta perspectiva, pode-se afirmar que os valores econômicos dos danos ambientais causados pelo processo erosão, nas Bacias dos Rios Atibaia e Jaguarí, portanto, não representam o valor econômico total do ambiente.bitstream/CNPMA/5814/1/documentos_40.pd

La régulation des plateformes dans le secteur du transport de passagers au Portugal et en Espagne: Stratégies différentes, coalitions différentes

Digital Platform Work (DPW) is part of a new phase of capitalism, in which monopolistic digital platforms use algorithms to mediate labour supply and demand. As DPW grows, the share of atypical workers in the labour market increases and European Union states are pressed to regulate it, but the strategies adopted are different. This is the case with the regulation of DPW in the passenger transport sector approved by the governments of Portugal and Spain. This paper makes a comparative analysis of these case studies based on parliamentary debates and media reports. We argue that the centre-left parties which led the governments in both countries, adopted a distinct regulation strategy because they each have specific conceptions of solidarity.info:eu-repo/semantics/publishedVersio

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

Radio emission from satellite-Jupiter interactions (especially Ganymede)

Analyzing a database of 26 years of observations of Jupiter from the Nan\c{c}ay Decameter Array, we study the occurrence of Io-independent emissions as a function of the orbital phase of the other Galilean satellites and Amalthea. We identify unambiguously the emissions induced by Ganymede and characterize their intervals of occurrence in CML and Ganymede phase and longitude. We also find hints of emissions induced by Europa and, surprisingly, by Amalthea. The signature of Callisto-induced emissions is more tenuous.Comment: 14 pages, 7 figures, in "Planetary Radio Emissions VIII", G. Fischer, G. Mann, M. Panchenko and P. Zarka eds., Austrian Acad. Sci. Press, Vienna, in press, 201

Informações sobre a fase de viveiro de algumas espécies florestais na Amazônia brasileira.

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