Stabilization of the Electroweak Scale in 3-3-1 Models

One way of avoiding the destabilization of the electroweak scale through a strong coupled regime naturally occurs in models with a Landau-like pole at the TeV scale. Hence, the quadratic divergence contributions to the scalar masses are not considered as a problem anymore since a new nonperturbative dynamic emerges at the TeV scale. This scale should be an intrinsic feature of the models and there is no need to invoke any other sort of protection for the electroweak scale. In some models based on the $SU(3)_C\otimes SU(3)_W\otimes U(1)_{X}$ gauge symmetry, a nonperturbative dynamics arise and it stabilizes the electroweak scale.Comment: 10 pages. Version with some improvements and corrections in the tex

A fast, preconditioned conjugate gradient Toeplitz and Toeplitz-like solvers

AbstractFor a Toeplitz or Toeplitz-like matrix T, we define a preconditioning applied to the symmetrized matrix THT, which decreases the condition number compared to the one of THT and even the one of T. This enables us to accelerate the conjugate gradient algorithm for solving Toepiltz and Toeplitz-like linear systems, thus extending the previous results of [1], restricted to the Hermitian positive definite case. The extension relies on some recent formulae of Gohberg and Olshevsky for the inverses of Toeplitz-like matrices

Polarization and Aharonov-Bohm oscillations in quantum-ring magnetoexcitons

We study interaction and radial polarization effects on the the absorption spectrum of neutral bound magnetoexcitons confined in quantum-ring structures. We show that the size and orientation of the exciton's dipole moment, as well as the interaction screening, play important roles in the Aharonov-Bohm oscillations. In particular, the excitonic absorption peaks display A-B oscillations both in position and amplitude for weak electron-hole interaction and large radial polarization. The presence of impurity scattering induces anticrossings in the exciton spectrum, leading to a modulation in the absorption strength. These properties could be used in experimental investigations of the effect in semiconductor quantum-ring structures.Comment: Updated version, 6 pages, 4 figures. To appear in Phys. Rev.

Transducer electronic data sheets: anywhere, anytime, anyway

Transducer electronic data sheets (TEDS) are a key element of smart transducers because they support core features such as plug and play, self-calibration, and self-diagnostics. The ISO/IEC/IEEE 21451-4 standard defines templates to describe the most common types of transducers and suggests the use of one-wire memories to store the corresponding data. In this paper we explore new ways to store and access TEDS tables, including near field communication (NFC) tags and QR codes. We also present a mobile TEDS parser, compatible with Android, that is capable of reading TEDS data from all supported mediums (one-wire memories, NFC tags, and QR codes) and decoding them as human-readable text. The idea is to make TEDS available in the easiest way possible. We also underline the need to extend the 21451-4 standard by adding support for frequency-time sensors. A new TEDS template is proposed, and filling examples are presented. The main novelties of the paper are (i) the proposal of new ways to store 21451-4 TEDS tables using NFC tags and QR codes; (ii) the release of new tools to access TEDS tables including a mobile parser; and (iii) the definition of a new TEDS template for frequency-time sensors.info:eu-repo/semantics/publishedVersio

Wavelets e uma aplicação na espectrometria

Nessa dissertação apresentamos um desenvolvimento matemático da construção de uma família de Wavelets, além de sua aplicação em um problema da espectrometria para a obtenção de propriedades do petróleo. Para tal, fazemos uso de outras ferramentas, como teoria Fuzzy, Algoritmo Genético e clusterização, obtendo um método de predição das propriedades. Por fim, apresentamos os resultados do método desenvolvido por meio dos espectros de amostras de petróleo, fornecidos pelo LabPetro-UFES

Study of latencies in ThingSpeak

IoT platforms play an important role on modern measurement systems because they allow the ingestion and processing of huge amounts of data (big data). Given the increasing use of these platforms, it is important to characterize their performance and robustness in real application scenarios. The paper analyzes the ThingSpeak platform by measuring the latencies associated to data packets sent to cloud and replied back, and by checking the consistency of the returned data. Several experiments were done considering different ways to access the platform: REST API, MQTT API, and MQTT broker alone. For each experiment, the methodology is explained, results are presented, and conclusions are extracted. The REST and MQTT APIs have similar performances, with roundtrip times between 1 s and 3 s. The MQTT broker alone is more agile, with roundtrip times below 250 ms. In all cases, the up and down links are far from being symmetric, with the uplink delay showing higher variance than the downlink delay. The obtained results can serve as a reference for other IoT platforms and provide guidelines for application development.info:eu-repo/semantics/publishedVersio

Low strength T-cross section RC beams shear-strengthened by NSM technique

In 2003 a research program started with the aim of developing design guidelines for the shear strengthening of T cross section reinforced concrete (RC) beams using carbon fiber reinforced polymer (CFRP) laminates applied according to the Near Surface Mounted (NSM) technique. The previous series of tested beams were mainly conceived to appraise the influence of parameters such as percentage and orientation of laminates. The occurrence of a failure mode consisting in the separation of the strengthened cover of the web lateral faces, prompted the authors to further in-vestigate the influence of the concrete mechanical properties. The series described in the present work comprehends ten beams characterized by low strength concrete. The main results are presented and analyzed also by comparison with those regarding a previous series characterized by the same test set-up and higher concrete strength.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/ECM/59033/2004Consorzio RELUIS. Dipartimento di Protezione Civil

Impurity-enhanced Aharonov-Bohm effect in neutral quantum-ring magnetoexcitons

We study the role of impurity scattering on the photoluminescence (PL) emission of polarized magnetoexcitons. We consider systems where both the electron and hole are confined on a ring structure (quantum rings) as well as on a type-II quantum dot. Despite their neutral character, excitons exhibit strong modulation of energy and oscillator strength in the presence of magnetic fields. Scattering impurities enhance the PL intensity on otherwise "dark" magnetic field windows and non-zero PL emission appears for a wide magnetic field range even at zero temperature. For higher temperatures, impurity-induced anticrossings on the excitonic spectrum lead to unexpected peaks and valleys on the PL intensity as function of magnetic field. Such behavior is absent on ideal systems and can account for prominent features in recent experimental results.Comment: 7 pages, 7 figures, RevTe

Biologia reprodutiva de pornunça (Manihot sp. - Euphorbiaceae) em área da Embrapa Semi-Árido, Petrolina-PE.

Com o objetivo de contribuir com informações sobre a biologia reprodutiva da espécie, o presente trabalho foi realizado na área da Embrapa Semi-Árido, PetrolinaPE (9º00? S, 40º22? W, 350 m de altitude) no período de janeiro a março 2003. As observações foram feitas em 12 indivíduos de Manihot sp., onde flores marcadas foram acompanhadas diariamente