Vibrational surface EELS probes confined Fuchs-Kliewer modes

Recently, two reports have demonstrated the amazing possibility to probe vibrational excitations from nanoparticles with a spatial resolution much smaller than the corresponding free-space phonon wavelength using electron energy loss spectroscopy (EELS). While Lagos et al. evidenced a strong spatial and spectral modulation of the EELS signal over a nanoparticle, Krivanek et al. did not. Here, we show that discrepancies among different EELS experiments as well as their relation to optical near- and far-field optical experiments can be understood by introducing the concept of confined bright and dark Fuchs-Kliewer modes, whose density of states is probed by EELS. Such a concise formalism is the vibrational counterpart of the broadly used formalism for localized surface plasmons; it makes it straightforward to predict or interpret phenomena already known for localized surface plasmons such as environment-related energy shifts or the possibility of 3D mapping of the related surface charge densities

Unveiling the Biometric Potential of Finger-Based ECG Signals

The ECG signal has been shown to contain relevant information for human identification. Even though results validate the potential of these signals, data acquisition methods and apparatus explored so far compromise user acceptability, requiring the acquisition of ECG at the chest. In this paper, we propose a finger-based ECG biometric system, that uses signals collected at the fingers, through a minimally intrusive 1-lead ECG setup recurring to Ag/AgCl electrodes without gel as interface with the skin. The collected signal is significantly more noisy than the ECG acquired at the chest, motivating the application of feature extraction and signal processing techniques to the problem. Time domain ECG signal processing is performed, which comprises the usual steps of filtering, peak detection, heartbeat waveform segmentation, and amplitude normalization, plus an additional step of time normalization. Through a simple minimum distance criterion between the test patterns and the enrollment database, results have revealed this to be a promising technique for biometric applications

ECG-based biometrics: A real time classification approach

Behavioral biometrics is one of the areas with growing interest within the biosignal research community. A recent trend in the field is ECG-based biometrics, where electrocardiographic (ECG) signals are used as input to the biometric system. Previous work has shown this to be a promising trait, with the potential to serve as a good complement to other existing, and already more established modalities, due to its intrinsic characteristics. In this paper, we propose a system for ECG biometrics centered on signals acquired at the subject's hand. Our work is based on a previously developed custom, non-intrusive sensing apparatus for data acquisition at the hands, and involved the pre-processing of the ECG signals, and evaluation of two classification approaches targeted at real-time or near real-time applications. Preliminary results show that this system leads to competitive results both for authentication and identification, and further validate the potential of ECG signals as a complementary modality in the toolbox of the biometric system designer

Bridging nano-optics and condensed matter formalisms in a unified description of inelastic scattering of relativistic electron beams

In the last decades, the blossoming of experimental breakthroughs in the domain of electron energy loss spectroscopy (EELS) has triggered a variety of theoretical developments. Those have to deal with completely different situations, from atomically resolved phonon mapping to electron circular dichroism passing by surface plasmon mapping. All of them rely on very different physical approximations and have not yet been reconciled, despite early attempts to do so. As an effort in that direction, we report on the development of a scalar relativistic quantum electrodynamic (QED) approach of the inelastic scattering of fast electrons. This theory can be adapted to describe all modern EELS experiments, and under the relevant approximations, can be reduced to any of the last EELS theories. In that aim, we present in this paper the state of the art and the basics of scalar relativistic QED relevant to the electron inelastic scattering. We then give a clear relation between the two once antagonist descriptions of the EELS, the retarded green Dyadic, usually applied to describe photonic excitations and the quasi-static mixed dynamic form factor (MDFF), more adapted to describe core electronic excitations of material. We then use this theory to establish two important EELS-related equations. The first one relates the spatially resolved EELS to the imaginary part of the photon propagator and the incoming and outgoing electron beam wavefunction, synthesizing the most common theories developed for analyzing spatially resolved EELS experiments. The second one shows that the evolution of the electron beam density matrix is proportional to the mutual coherence tensor, proving that quite universally, the electromagnetic correlations in the target are imprinted in the coherence properties of the probing electron beam.Comment: Re-Submission to SciPost. Updated version: minor revisions, SciPost templat

Physicochemical and microbiological changes in dried small-spotted catshark (Scyliorhynus canicula): developing an alternative shark-based salted-dried seafood product

A relatively high proportion of harvested seafood is still wasted due to spoilage, particularly in developing countries, or because they are by-catches or have little economic value, seemingly related to inherent problems linked to unattractive color, flavor, texture, small size, and high-fat content. Thus, many fish and seafood species are still underutilized.info:eu-repo/semantics/publishedVersio

Adubação foliar com fontes de potássio em batata, cvs. Asterix e Markies

Trabalho de Conclusão de Curso (Graduação)A cultura da batata (Solanum tuberosum L), tem grande importância socioeconômica mundial, figurando anualmente entre os alimentos mais consumidos no mundo.Visando um aumento de produção e de qualidade foi realizado um manejo de adubação potássica em via foliar utilizando fontes com Sulfato de potássio (K-Leaf) e Tiossulfato de potássio (KTS). A pesquisa teve como objetivo avaliar a influência da aplicação de adubos foliares, KTS e KLeaf, em condições de campo na região de Perdizes-MG durante o desenvolvimento dos cultivares Asterix e Markies. O delineamento experimental foi em blocos ao acaso, com seis tratamentos e quatro repetições para cada variedade, totalizando 48 parcelas. Os tratamentos foram constituídos de aplicações de adubos foliares K-Leaf e KTS K-leaf (8 kg ha-1 ) e KTS (5 kg ha-1 ) foram efetuadas com pulverizador costal pressurizado com CO2, realizadas em diferentes dias ao longo do ciclo da cultura, Foram realizadas três coletas de amostras de folhas, sendo cada uma 15 dias após as aplicações foliares dos tratamentos, qual foram coletadas a 3ª folha a partir do tufo apical, num total de 8 folhas por tratamento. Estas amostras foram analisadas quanto aos macros e micronutrientes para determinar o estado nutricional das plantas. Foram realizadas avaliações para as características pós-colheita: matéria seca; sólidos solúveis e coloração da fritura. Ao final do experimento, avaliaram-se características produtivas e qualitativas, concluise que a aplicação do KTS 36 e 51 dias após o plantio, resultou em ganho de produção comercial na variedade Markies. Em relação aos atributos pós-colheita, não houve influência nos tratamento

A evolução da abordagem farmacológica no tratamento contra a COVID-19

A COVID-19 é uma doença causada pelo vírus SARS-CoV-2, um vírus emergente que foi descoberto no final do ano de 2019 na China. No dia 11 de março de 2020 a doença foi declarada como pandemia pela Organização Mundial da Saúde devido aos níveis alarmantes de propagação e gravidade, tendo-se verificado vários impactos sociais, económicos e políticos a nível nacional e mundial. A proveniência exata do vírus é desconhecida, mas tudo leva a crer que seja de origem zoonótica. Recentemente, as terapêuticas existentes destinavam-se a atenuar os sintomas e a torná-los mais toleráveis. As vacinas anti-COVID-19 foram desde o início da pandemia um objetivo a alcançar de modo a garantir a saúde da população. Para surpresa de muitos e ao contrário do que se esperava, ao fim de um ano de pandemia começaram a ser anunciadas as primeiras vacinas anti-COVID-19, tendo contribuído para a redução da mortalidade em mais de 50% na região europeia da Organização Mundial de Saúde. Muitos fármacos foram inicialmente usados de forma off-label para tratar a COVID-19, como a ivermectina e a hidroxicloroquina, porém, mais tarde vieram a demonstrar-se inúteis. O soro convalescente também não evidenciou benefício terapêutico. Já fármacos como o remdesivir, a associação nirmatrelvir + ritonavir, a dexametasona, o molnupiravir e o tocilizumab exibiram potencial a nível clínico conseguindo de uma forma transversal reduzir a taxa de mortalidade e, em certos casos, diminuir também o número de internamentos ou o tempo de hospitalização. Com vista a que a doença se torne endémica e com o objetivo de assegurar uma proteção eficaz e duradora da população, novas estratégias terapêuticas têm de ser estudadas e desenvolvidas. De entre os vários medicamentos atualmente investigados e incluídos em ensaios clínicos, o Vaxart (vacina oral) e o SNG001 têm se evidenciado promissores para serem terapeuticamente aplicados num futuro próximo.COVID-19 is a disease caused by the SARS-CoV-2 virus, an emerging virus that was discovered in late 2019 in China. On March 11, 2020, the disease was declared a pandemic by the World Health Organization due to the alarming levels of spread and severity, with several social, economic, and political impacts at national and global level. The etiology of the virus is unknown, but everything suggests that it is of zoonotic origin. Recently, the existing therapies were aimed at alleviating symptoms and making them more tolerable. Vaccines anti-COVID-19 have been a goal to achieve since the beginning of the pandemic in order to guarantee the health of the population. To the suprise of many and in contrast to what was expected, after a year of pandemic, the first vacines against COVID-19 began to be announced, having contributed to the reduction of mortality by more than 50% in the World Health Organization European region. Many drugs were initially used off-label for the treatment of COVID-19, such as ivermectin and hydroxychloroquine, but later proved to be useless. Convalescent serum also showed no therapeutic benefit. Drugs such as remdesivir, the combination nirmatrelvir + ritonavir, dexamethasone, molnupiravir and tocilizumab showed potential at a clinical level, achieving a transversal reduction in the mortality rate and, in certain cases, also decreasing the number of hospitalizations or the time of hospitalization. In order for the disease to become endemic and in order to ensure an effective and lasting protection for the population, new therapeutic strategies must be studied and developed. Among the various drugs currently investigated and included in clinical trials, Vaxart (oral vaccine) and SNG001 have shown promising results to be therapeutically applied in the near future