Complete light absorption in graphene-metamaterial corrugated structures

We show that surface-plasmon polaritons excited in negative permittivity metamaterials having shallow periodic surface corrugation profiles can be explored to push the absorption of single and continuous sheets of graphene up to 100%. In the relaxation regime, the position of the plasmonic resonances of the hybrid system is determined by the plasma frequency of the metamaterial, allowing the frequency range for enhanced absorption to be set without the need of engineering graphene.Comment: 6 pages, 4 figures; published version: text revised and references adde

Confined magneto-optical waves in graphene

The electromagnetic mode spectrum of single-layer graphene subjected to a quantizing magnetic field is computed taking into account intraband and interband contributions to the magneto-optical conductivity. We find that a sequence of weakly decaying quasi-transverse-electric modes, separated by magnetoplasmon polariton modes, emerge due to the quantizing magnetic field. The characteristics of these modes are tuneable, by changing the magnetic field or the Fermi energy.Comment: 9 pages, 7 figures. published version: text and figures revised and updated + new references and one figure adde

Physics Beyond the Standard Model: Focusing on the Muon Anomaly

We present a model based on the implication of an exceptional E_{6}-GUT symmetry for the anomalous magnetic moment of the muon. We follow a particular chain of breakings with Higgses in the 78 and 351 representations. We analyse the radiative correction contributions to the muon mass and the effects of the breaking of the so-called Weinberg symmetry. We also estimate the range of values of the parameters of our model.Comment: 14 RevTeX pages, 5 figure

Combination of gemcitabine with cell-penetrating peptides: A pharmacokinetic approach using in silico tools

Gemcitabine is an anticancer drug used to treat a wide range of solid tumors and is a first line treatment for pancreatic cancer. Our group has previously developed novel conjugates of gemcitabine with cell-penetrating peptides (CPP), and here we report some preliminary data regarding the pharmacokinetics of gemcitabine, two gemcitabine-CPP conjugates and respective CPP gathered from GastroPlus™, and analyze these results considering our previous evaluation of gemcitabine release and conjugates’ bioactivity. Additionally, seeking to shed some light on the relation between the penetration ability of CPP and their physicochemical properties, chemical descriptors for the 20 natural amino acids were calculated, a new principal property scale (z-scale) was created and CPP prediction models were developed, establishing quantitative structure-activity relationships (QSAR). The z-scores of the peptides conjugated with gemcitabine are presented and analyzed with the aforementioned data.This work has been financed by Fundo Europeu de Desenvolvimento Regional (FEDER) funds through the COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation (POCI) and Portugal 2020, and Portuguese funds through Fundação para a Ciência e a Tecnologia (FCT, Portugal), in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274), and through grant UID/QUI/50006/2019 (LAQV-REQUIMTE). NV also acknowledges support from FCT and FEDER (European Union), award number IF/00092/2014/CP1255/CT0004. AF thanks FCT for a doctoral fellowship (PD/BD/135120/2017)

Critical temperature of a fully anisotropic three-dimensional Ising model

The critical temperature of a three-dimensional Ising model on a simple cubic lattice with different coupling strengths along all three spatial directions is calculated via the transfer matrix method and a finite size scaling for L x L oo clusters (L=2 and 3). The results obtained are compared with available calculations. An exact analytical solution is found for the 2 x 2 oo Ising chain with fully anisotropic interactions (arbitrary J_x, J_y and J_z).Comment: 17 pages in tex using preprint.sty for IOP journals, no figure

A BWM approach to determinants of sustainable entrepreneurship in small and medium-sized enterprises

Small and medium-sized enterprises (SMEs) constitute an extremely large percentage of most nations’ businesses. These companies are also expressing growing concerns about sustainability and its strategic integration into operations. However, SMEs have been prevented from making investments in sustainability by the absence of a holistic view of this topic, an overemphasis on an economic perspective, and the consequent devaluation of environmental and social perspectives. In this context, greater importance needs to be given to investigating SME sustainability and building a transparent, holistic, and realistic business model. The present study combines cognitive mapping and the best worst method (BWM) to identify determinants of sustainable entrepreneurship in SMEs. These techniques were applied in two meetings with a panel of specialists with knowledge about and experience in this subject matter. The insights obtained during the two panel meetings allowed the proposed process-oriented approach to assist decision-makers in analyzing a sample of SMEs and selecting the ones that best match the following clusters of decision criteria: (1) entrepreneur profile; (2) firm internal characteristics; (3) economic factors; (4) other external factors; and (5) market. The results were validated by four representatives of the Portuguese Institute for Small and Medium-sized Enterprises and Innovation (Instituto de Apoio às Pequenas e Médias Empresas e à Inovação (IAPMEI) in Portuguese). The study’s contributions and limitations are also discussed.info:eu-repo/semantics/publishedVersio

The magnetic Purcell effect: the case of an emitter near an antiferromagnet

In this paper we discuss the magnetic Purcell effect of a magnetic dipole near a semi-infinite antiferromagnet. Contrary to the electric Purcell effect, the magnetic one is not so well studied in the literature. We derive the dispersion relation of the surface wave existing at an antiferromagnetic-dielectric interface from the calculation of the reflection coefficient of the structure. After characterizing the surface wave we quantize the electromagnetic vector potential of the surface wave. This allows us to discuss the magnetic Purcell effect via the Fermi golden rule. Copyright (C) EPLA, 2019- BAF and NMRP acknowledge discussions on the topic of this paper with Bruno Amorim and Gil Farias, and the Center of Physics of the University of Minho and the University of Porto for funding in the framework of the Strategic Financing UID/FIS/04650/2013. NMRP acknowledges support from the European Commission through the project "Graphene-Driven Revolutions in ICT and Beyond" (Ref. No. 785219), COMPETE2020, PORTUGAL2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) through project POCI-01-0145-FEDER-028114

Cosmic String Wakes in Scalar-Tensor Gravities

The formation and evolution of cosmic string wakes in the framework of a scalar-tensor gravity are investigated in this work. We consider a simple model in which cold dark matter flows past an ordinary string and we treat this motion in the Zel'dovich approximation. We make a comaprison between our results and previous results obtained in the context of General Relativity. We propose a mechanism in which the contribution of the scalar field to the evolution of the wakes may lead to a cosmological observation.Comment: Replaced version to be published in the Classical and Quantum Gravit