Modulating spin transfer torque switching dynamics with two orthogonal spin-polarizers by varying the cell aspect ratio

We study in-plane magnetic tunnel junctions with additional perpendicular polarizer for subnanosecond-current-induced switching memories. The spin-transfer-torque switching dynamics was studied as a function of the cell aspect ratio both experimentally and by numerical simulations using the macrospin model. We show that the anisotropy field plays a significant role in the dynamics, along with the relative amplitude of the two spin-torque contributions. This was confirmed by micromagnetic simulations. Real-time measurements of the reversal were performed with samples of low and high aspect ratio. For low aspect ratios, a precessional motion of the magnetization was observed and the effect of temperature on the precession coherence was studied. For high aspect ratios, we observed magnetization reversals in less than 1 ns for high enough current densities, the final state being controlled by the current direction in the magnetic tunnel junction cell.Comment: 6 pages, 7 figure

HIV knowledge and its correlation with the Undetectable = Untransmittable slogan in Brazil

Knowledge about HIV transmission and prevention is a necessary step for adopting preventive behaviors. We assessed HIV knowledge and its correlation with the perceived accuracy of the “Undetectable = Untransmittable” (U=U) slogan in an online sample with 401 adult Brazilians. Overall, 28% of participants showed high HIV knowledge level. The perceived accuracy of the U=U slogan significantly correlated with HIV knowledge. Younger participants, those reporting lower income or lower education, or who had never tested for HIV showed poorer HIV knowledge. Filling gaps of knowledge among specific populations is urgent in order to increase preventive behaviors and decrease HIV stigma

Improved coherence of ultrafast spin-transfer-driven precessional switching with synthetic antiferromagnet perpendicular polarizer

International audienceThe coherence of the precessional switching was compared in planar spin-valves comprising either an additional simple perpendicular polarizer or a synthetic antiferromagnet perpendicular polarizer. A significant improvement in the precession coherence was observed experimentally in the second type of samples. Micromagnetic simulations were performed to study the effect of the stray field from the perpendicular polarizer. They provide an explanation for the gradual loss of coherence of the precession in terms of vortex formation, which occurs much faster when a simple perpendicular polarizer is used

High rates of physical inactivity and cardiovascular risk factors in patients with resistant hypertension

Background: Hypertension.is a multifactorial disease of high prevalence in Brazil and the world’s population and is the major treatable risk factor for cardiovascular disease. Objectives: To investigate the prevalence, according to sex, of risk behaviors and comorbidities associated with Hypertension.in the treated patients in Hiperdia Center Viçosa, MG. Methods: Cross-sectional study that evaluated 172 medical records of hypertensive patients greater than 18 years, nondiabetic, referred to the center of Viçosa Hiperdia. Among the data evaluated from analysis of medical records are the factors and behaviors of cardiovascular risk as overweight / obesity, dyslipidemia, smoking, drinking and physical inactivity, as well as medical conditions or comorbidities associated with hypertension. For data analysis were used the Kolmogorov-Smirnov test, Mann-Whitney test and the Pearson correlation test. The level of significance was 5%. Results: There was a higher prevalence of men among the patients and rates of alcoholism and smoking were significantly higher in this group. Women had a higher rate of obesity. Physical inactivity and dyslipidemia were present in 77% and 44% of patients, respectively, with no difference between sexes. Resistant Hypertension.was found in 71% of patients. Lower education was also very present among the hypertensive. Among the clinical conditions related to hypertension, there was a predominance of left ventricular hypertrophy, followed by kidney disease and cerebrovascular disease. Conclusions: The study showed that 71% of patients were classified as resistant Hypertension.and that, beyond this serious condition, they still showed a combination of behaviors and risk factors that confer a high risk of cardiovascular complicationsFundamento: A hipertensão arterial sistêmica é uma doença multifatorial, de alta prevalência na população brasileira e mundial e constitui o principal fator de risco tratável para as doenças cardiovasculares. Objetivos: Verificar a prevalência, de acordo com o sexo, dos comportamentos de risco e das comorbidades associadas à hipertensão nos pacientes atendidos no Centro Hiperdia de Viçosa, MG Métodos: Estudo transversal que avaliou 172 prontuários de hipertensos maiores de 18 anos, não diabéticos, encaminhados ao Centro Hiperdia de Viçosa. Entre os dados avaliados a partir de análise de prontuários estão os fatores e comportamentos de risco cardiovascular como sobrepeso/obesidade, dislipidemia, tabagismo, etilismo e sedentarismo, bem como condições clínicas ou comorbidades associadas à HAS. Para análise dos dados foram empregados os testes de Kolmogorov-Smirnov, o teste de Mann-Whitney e o teste de correlação de Pearson. O nível de significância adotado foi de 5%. Resultados: Observou-se uma prevalência maior de homens entre os hipertensos analisados e as taxas de etilismo e tabagismo foram significativamente maiores neste grupo. As mulheres apresentaram uma taxa maior de obesidade. O sedentarismo e a dislipidemia estiveram presentes em 77% e 44% dos pacientes, respectivamente, sem diferença entre os sexos. Hipertensão arterial resistente foi encontrada em 71% dos pacientes. Dentre as condições clínicas relacionadas à hipertensão, houve um predomínio da hipertrofia do ventrículo esquerdo, seguida pela doença renal e pela doença cerebrovascular. Conclusões: O estudo mostrou que 71 % dos pacientes eram classificados como hipertensos resistentes e que, além desta séria condição, os mesmos ainda apresentavam uma combinação de comportamentos e fatores de risco que conferem um alto risco de complicações cardiovasculare

The BINGO Project IX: Search for Fast Radio Bursts -- A Forecast for the BINGO Interferometry System

The Baryon Acoustic Oscillations (BAO) from Integrated Neutral Gas Observations (BINGO) radio telescope will use the neutral Hydrogen emission line to map the Universe in the redshift range $0.127 \le z \le 0.449$, with the main goal of probing BAO. In addition, the instrument optical design and hardware configuration support the search for Fast Radio Bursts (FRBs). In this work, we propose the use of a BINGO Interferometry System (BIS) including new auxiliary, smaller, radio telescopes (hereafter \emph{outriggers}). The interferometric approach makes it possible to pinpoint the FRB sources in the sky. We present here the results of several BIS configurations combining BINGO horns with and without mirrors ($4$ m, $5$ m, and $6$ m) and 5, 7, 9, or 10 for single horns. We developed a new {\tt Python} package, the {\tt FRBlip}, which generates synthetic FRB mock catalogs and computes, based on a telescope model, the observed signal-to-noise ratio (S/N) that we used to compute numerically the detection rates of the telescopes and how many interferometry pairs of telescopes (\emph{baselines}) can observe an FRB. FRBs observed by more than one baseline are the ones whose location can be determined. We thus evaluate the performance of BIS regarding FRB localization. We found that BIS will be able to localize 23 FRBs yearly with single horn outriggers in the best configuration (using 10 outriggers of 6 m mirrors), with redshift $z \leq 0.96$; the full localization capability depends on the number and the type of the outriggers. Wider beams are best to pinpoint FRB sources because potential candidates will be observed by more baselines, while narrow beams look deep in redshift. The BIS can be a powerful extension of the regular BINGO telescope, dedicated to observe hundreds of FRBs during Phase 1. Many of them will be well localized with a single horn + 6 m dish as outriggers.(Abridged)Comment: 12 pages, 9 figures, 5 tables, submitted to A&

Can we predict real-time fMRI neurofeedback learning success from pretraining brain activity?

Neurofeedback training has been shown to influence behavior in healthy participants as well as to alleviate clinical symptoms in neurological, psychosomatic, and psychiatric patient populations. However, many real-time fMRI neurofeedback studies report large inter-individual differences in learning success. The factors that cause this vast variability between participants remain unknown and their identification could enhance treatment success. Thus, here we employed a meta-analytic approach including data from 24 different neurofeedback studies with a total of 401 participants, including 140 patients, to determine whether levels of activity in target brain regions during pretraining functional localizer or no-feedback runs (i.e., self-regulation in the absence of neurofeedback) could predict neurofeedback learning success. We observed a slightly positive correlation between pretraining activity levels during a functional localizer run and neurofeedback learning success, but we were not able to identify common brain-based success predictors across our diverse cohort of studies. Therefore, advances need to be made in finding robust models and measures of general neurofeedback learning, and in increasing the current study database to allow for investigating further factors that might influence neurofeedback learning

BeyondPlanck IV. On end-to-end simulations in CMB analysis -- Bayesian versus frequentist statistics

End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by any other means. In this paper, we address an important issue regarding such simulations, namely how to define the inputs in terms of sky model and instrument parameters. These may either be taken as a constrained realization derived from the data, or as a random realization independent from the data. We refer to these as Bayesian and frequentist simulations, respectively. We show that the two options lead to significantly different correlation structures, as frequentist simulations, contrary to Bayesian simulations, effectively include cosmic variance, but exclude realization-specific correlations from non-linear degeneracies. Consequently, they quantify fundamentally different types of uncertainties, and we argue that they therefore also have different and complementary scientific uses, even if this dichotomy is not absolute. Before BeyondPlanck, most pipelines have used a mix of constrained and random inputs, and used the same hybrid simulations for all applications, even though the statistical justification for this is not always evident. BeyondPlanck represents the first end-to-end CMB simulation framework that is able to generate both types of simulations, and these new capabilities have brought this topic to the forefront. The Bayesian BeyondPlanck simulations and their uses are described extensively in a suite of companion papers. In this paper we consider one important applications of the corresponding frequentist simulations, namely code validation. That is, we generate a set of 1-year LFI 30 GHz frequentist simulations with known inputs, and use these to validate the core low-level BeyondPlanck algorithms; gain estimation, correlated noise estimation, and mapmaking

THE STRUCTURE OF SUBTIDAL MACROALGAL ASSEMBLAGES AT THE TAMOIOS ECOLOGICAL STATION, A THREATENED CONSERVATION UNIT IN RIO DE JANEIRO, BRAZIL

The structure of subtidal rocky bottom communities at Tamoios Ecological Station (TES), situated in Ilha Grande Bay, Rio de Janeiro State, as well as in other Brazilian marine protected areas, is insufficiently characterized. The present study describes the macroalgal assemblages of shallow subtidal rocky bottoms on two islands of the TES-Imboassica (IM) and Búzios Pequena (BP)adopting species and genera as observational units. Two sites were surveyed on each island in summer 2011. Random 30x30 cm quadrats (n=3) were scraped to collect all macroalgae except crustose species. The subtidal assemblages, in which 58 macroalgal species occurred, were characterized by the high frequency and percent cover of Sargassum vulgare C. Agardh (56.8±8.4%). The sites differed significantly in total number of species and Shannon-Weiner diversity index (PERMANOVA, p5%) were Sargassum, Laurencia, Wrangelia, Canistrocarpus, Asparagopsis, Hypnea, Ceratodictyon, Gayliella, Spyridia and Chondria.Dissimilarities within and between the islands, as shown by nMDS of the cover data, suggest that different spatial scales should be considered in monitoring the rocky bottom communities of Ilha Grande Bay