New linearization and reweighting for simulations of string sigma-model on the lattice

We study the discretized worldsheet of Type IIB strings in the Gubser-Klebanov-Polyakov background in a new setup, which eliminates a complex phase previously detected in the fermionic determinant. A sign ambiguity remains, which a study of the fermionic spectrum shows to be related to Yukawa-like terms, including those present in the original Lagrangian before the linearization standard in a lattice QFT approach. Monte Carlo simulations are performed in a large region of the parameter space, where the sign problem starts becoming severe and instabilities appear due to the zero eigenvalues of the fermionic operator. To face these problems, simulations are conducted using the absolute value of a fermionic Pfaffian obtained introducing a small twisted-mass term, acting as an infrared regulator, into the action. The sign of the Pfaffian and the low modes of the quadratic fermionic operator are then taken into account by a reweighting procedure of which we discuss the impact on the measurement of the observables. In this setup we study bosonic and fermionic correlators and observe a divergence in the latter, which we argue - also via a one-loop analysis in lattice perturbation theory - to originate from the U(1)-breaking of our Wilson-like discretization for the fermionic sector

Strings on the lattice and AdS/CFT

We present a new auxiliary field representation for the four-fermi term of the gauge-fixed Green-Schwarz superstring action which describes fluctuations around the null-cusp background in $AdS_5\times S^5$. We sketch the main features of the fermionic operator spectrum, identifying the region of parameter space where the sign ambiguity is absent. Measurements for the observables in the setup here described are presented and discussed in a forthcoming publication

Radiography registration for mosaic tomography

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQA hybrid method of stitching X-ray computed tomography (CT) datasets is proposed and the feasibility to apply the scheme in a synchrotron tomography beamline with micrometre resolution is shown. The proposed method enables the field of view of the system to be extended while spatial resolution and experimental setup remain unchanged. The approach relies on taking full tomographic datasets at different positions in a mosaic array and registering the frames using Fourier phase correlation and a residue-based correlation. To ensure correlation correctness, the limits for the shifts are determined from the experimental motor position readouts. The masked correlation image is then minimized to obtain the correct shift. The partial datasets are blended in the sinogram space to be compatible with common CT reconstructors. The feasibility to use the algorithm to blend the partial datasets in projection space is also shown, creating a new single dataset, and standard reconstruction algorithms are used to restore high-resolution slices even with a small number ofprojections.A hybrid method of stitching X-ray computed tomography (CT) datasets is proposed and the feasibility to apply the scheme in a synchrotron tomography beamline with micrometre resolution is shown. The proposed method enables the field of view of the system to be extended while spatial resolution and experimental setup remain unchanged. The approach relies on taking full tomographic datasets at different positions in a mosaic array and registering the frames using Fourier phase correlation and a residue-based correlation. To ensure correlation correctness, the limits for the shifts are determined from the experimental motor position readouts. The masked correlation image is then minimized to obtain the correct shift. The partial datasets are blended in the sinogram space to be compatible with common CT reconstructors. The feasibility to use the algorithm to blend the partial datasets in projection space is also shown, creating a new single dataset, and standard reconstruction algorithms are used to restore high-resolution slices even with a small number of projections.243686694CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSem informaçã

Avaliação dos pés de pessoas com diabetes mellitus: o uso de um aplicativo móvel.

Introdução: Diabetes Mellitus é um sério problema de saúde pública responsável por diversas complicações crônicas, dentre elas, o pé diabético, cujas conseqüências apontam para amputações de membros inferiores, podendo levar a morte, redução da qualidade de vida, além de gerar grande impacto socioeconômico. O enfermeiro, enquanto profissional na atenção direta à pessoa com diabetes, é essencial no desenvolvimento de ações para prevenção de riscos, monitoramento da clínica, controle da doença e de complicações. Objetivo: Descrever o desenvolvimento e validação de um aplicativo para dispositivos móveis sobre avaliação e classificação de risco dos pés de pessoas com Diabetes Mellitus. Metodologia: Estudo metodológico realizado em quatro etapas: 1) Definição de requisitos e elaboração do modelo conceitual; 2) Geração das alternativas de implementação e prototipagem; 3) Testes; e 4) Implementação. Considerando a especificidade de conhecimento em tecnologias exigida para concretização do produto desejado, todas as etapas do estudo foram desenvolvidas na Universidade Federal do Espírito Santo (UFES) numa parceria entre o Programa de Pós-Graduação em enfermagem (PPGENF), projeto de extensão Cuidar Tech (Laboratório de Tecnologias de Enfermagem) e o Laboratório e Observatório de Ontologias Projetuais (LOOP), vinculado ao Departamento de Desenho Industrial. O método geral de desenvolvimento do aplicativo foi orientado pela norma ABNT ISO/TR 16982:2014. No primeiro momento para elaboração da parte textual de cada tela foram utilizados guidelines publicados na Europa e Américas. Geradas opções de elaboração e prototipagem utilizando o software Intel XDK. Na etapa dos testes o produto foi avaliado quanto a usabilidade pelas heurísticas de Nielson, pela equipe que desenvolveu o aplicativo e validado quanto aos aspectos de funcionalidade, confiabilidade, usabilidade e eficiência por oito enfermeiros, selecionados de forma aleatória por conveniência, obedecendo a norma Brasileira ABNT ISO/IEC 25062:2011 que recomenda amostragem mínima de oito participantes. Na última etapa foi lançado na loja de aplicativos Google Play Store. Resultados: Na avaliação de usabilidade pela heurística de Nielson foram detectados quatro problemas catastróficos e quatro graves gerando modificações. A avaliação dos enfermeiros anunciou que o aplicativo móvel Cuidar Tech exame dos pés está de acordo com as necessidades dos usuários. Produtos: Um manuscrito e uma produção técnica. O manuscrito retrata o desenvolvimento do aplicativo móvel e o produto foi intitulado Cuidar Tech exame dos pés. Conclusão: Espera-se auxiliar os enfermeiros na avaliação e classificação de risco dos pés de pessoas com Diabetes Mellitus, ofertando uma ferramenta tecnológica que contribua na prática do enfermeiro assessorando seu desempenho na assistência e ampliando a resolutividade da Atenção Primária à Saúde. PALAVRAS CHAVES: Diabetes Mellitus. Avaliação de enfermagem. Pé. Aplicativos Móveis

Green-Schwarz superstring on the lattice

We consider possible discretizations for a gauge-fixed Green-Schwarz action of Type IIB superstring. We use them for measuring the action, from which we extract the cusp anomalous dimension of planar N=4 SYM as derived from AdS/CFT, as well as the mass of the two AdS excitations transverse to the relevant null cusp classical string solution. We perform lattice simulations employing a Rational Hybrid Monte Carlo (RHMC) algorithm and two Wilson-like fermion discretizations, one of which preserves the global SO(6) symmetry the model. We compare our results with the expected behavior at various values of g=λ√4π . For both the observables, we find a good agreement for large g, which is the perturbative regime of the sigma-model. For smaller values of g, the expectation value of the action exhibits a deviation compatible with the presence of quadratic divergences. After their non-perturbative subtraction the continuum limit can be taken, and suggests a qualitative agreement with the non-perturbative expectation from AdS/CFT. Furthermore, we detect a phase in the fermion determinant, whose origin we explain, that for small g leads to a sign problem not treatable via standard reweigthing. The continuum extrapolations of the observables in the two different discretizations agree within errors, which is strongly suggesting that they lead to the same continuum limit. Part of the results discussed here were presented earlier in [1]

Lattice and string worldsheet in AdS/CFT: a numerical study

We consider a possible discretization for the gauge-fixed Green-Schwarz (two-dimensional) sigma-model action for the Type IIB superstring and use it for measuring the cusp anomalous dimension of planar $\mathcal{N}=4$ SYM as derived from string theory. We perform lattice simulations employing a Rational Hybrid Monte Carlo (RHMC) algorithm and a Wilson-like fermion discretization. In this preliminary study, we compare our results with the expected behavior for very large values of $g=\frac{\sqrt{\lambda}}{4\pi}$, which is the perturbative regime of the sigma-model, and find a qualitative agreement at finite lattice spacing. For smaller $g$ the continuum limit is obstructed by a divergence. We also detect a phase in the fermion determinant, whose origin we explain, which for small $g$ leads to a sign problem not treatable via standard reweigthing. Results presented here are discussed thoroughly in~\cite{toappear}

Electronics and data acquisition demonstrator for a kinetic inductance camera

A prototype of digital frequency multiplexing electronics allowing the real time monitoring of kinetic inductance detector (KIDs) arrays for mm-wave astronomy has been developed. It requires only 2 coaxial cables for instrumenting a large array. For that, an excitation comb of frequencies is generated and fed through the detector. The direct frequency synthesis and the data acquisition relies heavily on a large FPGA using parallelized and pipelined processing. The prototype can instrument 128 resonators (pixels) over a bandwidth of 125 MHz. This paper describes the technical solution chosen, the algorithm used and the results obtained

The influence of outdoor air pollution on cadmium exposure assessment: a cross-sectional population-based Italian study.

The influence of outdoor air pollution on cadmium exposure assessment: a cross-sectional population-based Italian study

Supporting Earth-Observation Calibration and Validation: A new generation of tools for crowdsourcing and citizen science

Citizens are providing vast amounts of georeferenced data in the form of in situ data collections as well as interpretations and digitization of Earth-observation (EO) data sets. These new data streams have considerable potential for supporting the calibration and validation of current and future products derived from EO. We provide a general introduction to this growing area of interest and review existing crowdsourcing and citizen science (CS) initiatives of relevance to EO. We then draw upon our own experiences to provide case studies that highlight different types of data collection and citizen engagement and discuss the various barriers to adoption. Finally, we highlight opportunities for how citizens can become part of an integrated EO monitoring system in the framework of the European Union (EU) space program, including Copernicus and other monitoring initiatives