1,786 research outputs found

    Use of Social Media During The Covid-19 Pandemic of 2020

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    Nowadays billions of people use social media platforms as a way to keep in touch with family and friends, fill spare time, find content, find inspiration for things to do and buy, share, and discuss opinions with others, and the list goes on. This project focused and investigated on the use of social media during the years, in particular during quarantine/lockdown. Utilizing the public source data, I explored several research questions including how many hours people spent on social media, the popularity of social media apps, as well as what age group uses social media platforms (teenagers, young adults, adults). After data cleaning, the data visualization followed, and multiple dashboards were created using Tableau; the data analysis was mainly completed in R. The findings and analysis results were also presented in this research

    Assessing Cu impacts on freshwater diatoms: biochemical and metabolomic responses of Tabellaria flocculosa (Roth) Kutzing

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    Metals are a recognised threat to aquatic organisms but the impact of metals such as copper (Cu) on benthic freshwater diatoms is poorly understood, even if diatoms are commonly used as water quality indicators. Our study aimed to elucidate the cellular targets of Cu toxicity and the mechanisms cells resort to counteract toxicity and to increase tolerance to Cu. A concerted approach analysing the biochemical, physiological and metabolome alterations in diatom cells was conducted by exposing the freshwater diatom Tabellaria flocattosa to 0, 0.3, 6 and 10 mu g Cu/L. Cu was already toxic to T. flocculosa at concentrations common in environments and which are not usually considered to be contaminated (0.3 mu g Cu/L). Under Cu impact, the metabolome of T. flocculosa changed significantly, especially at high concentrations (6 and 10 mu g Cu/L). Cu toxicity was counteracted by increasing extracellular immobilization (EPS, frustulins), antioxidant (SOD, CAT) and detoxifying (GSTs) enzymes activity and low molecular weight antioxidants (GSH). These mechanisms were fuelled by higher energy production (increased ETS activity). At the highest Cu concentration (10 mu g/L), these processes were specially enhanced in an attempt to restrain the oxidative stress generated by high intracellular Cu concentrations. However, these mechanisms were not able to fully protect cells, and damage in membranes and proteins increased. Moreover, the decrease of hydroxylamine and unsaturated fatty acids and the increase of saturated fatty acids, 2-palmiloylglycerol, glycerol and diterpenoid compounds should be tested as new specific markers of Cu toxicity in future studies. This information can support the prediction of diatom behaviour in different Cu contamination levels, including highly impacted environments, such as mining scenarios, and may assist in environmental risk assessment policies and restoration programs. (C) 2018 Elsevier B.V. All rights reserved

    Electrical transport properties of CuS single crystals

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    Electrical resistivity, transverse magnetoresistance and thermoelectric power measurements were performed on CuS high quality single crystals in the range 1.2-300 K and under fields of up to 16 T. The zero field resistivity data are well described below 55 K by a quasi-2D model, consistent with a carrier confinement at lower temperatures, before the transition to the superconducting state. The transverse magnetoresistance develops mainly below 30 K and attains values as large as 470% for a 16 T field at 5 K, this behaviour being ascribed to a band effect mechanism, with a possible magnetic field induced DOS change at the Fermi level. The transverse magnetoresistance shows no signs of saturation, following a power law with field Delta rho/rho(0) proportional to H(1.4), suggesting the existence of open orbits for carriers at the Fermi surface. The thermoelectric power shows an unusual temperature dependence, probably as a result of the complex band structure of CuS

    Non-traditional students in higher education: barriers to learning and professional insertion

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    This article emerges from two research projects focused on non-traditional students in higher education. Our objectives aims to understand the barriers of learning and academic success, considering the perspectives of the several social actors in the academia; and to understand the barriers of the same students had in their transition to the work environment. The results show that a set of situational and institutional factors work as obstacles to these students. The results also show that age is a determinant factor regarding hiring and that the characteristics of the labour market today make hard the professional insertion of non-traditional undergraduates

    Low-complexity DCD-based sparse recovery algorithms

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    Sparse recovery techniques find applications in many areas. Real-time implementation of such techniques has been recently an important area for research. In this paper, we propose computationally efficient techniques based on dichotomous coordinate descent (DCD) iterations for recovery of sparse complex-valued signals. We first consider â„“2â„“1\ell_2 \ell_1 optimization that can incorporate \emph{a priori} information on the solution in the form of a weight vector. We propose a DCD-based algorithm for â„“2â„“1\ell_2 \ell_1 optimization with a fixed â„“1\ell_1-regularization, and then efficiently incorporate it in reweighting iterations using a \emph{warm start} at each iteration. We then exploit homotopy by sampling the regularization parameter and arrive at an algorithm that, in each homotopy iteration, performs the â„“2â„“1\ell_2 \ell_1 optimization on the current support with a fixed regularization parameter and then updates the support by adding/removing elements. We propose efficient rules for adding and removing the elements. The performance of the homotopy algorithm is further improved with the reweighting. We then propose an algorithm for â„“2â„“0\ell_2 \ell_0 optimization that exploits homotopy for the â„“0\ell_0 regularization; it alternates between the least-squares (LS) optimization on the support and the support update, for which we also propose an efficient rule. The algorithm complexity is reduced when DCD iterations with a \emph{warm start} are used for the LS optimization, and, as most of the DCD operations are additions and bit-shifts, it is especially suited to real time implementation. The proposed algorithms are investigated in channel estimation scenarios and compared with known sparse recovery techniques such as the matching pursuit (MP) and YALL1 algorithms. The numerical examples show that the proposed techniques achieve a mean-squared error smaller than that of the YALL1 algorithm and complexity comparable to that of the MP algorithm

    MAPEAMENTO TECNOLÓGICO DE REAÇÕES DO COMPOSTO TIOUREAS COM MOLÉCULAS DE AMIDA NA OBTENÇÃO DE PRODUTOS FARMACÊUTICOS DE USO COSMÉTICO E TERAPÊUTICO

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    As reações enzimáticas de proteínas inibidoras vêm se tornando importante fonte de estudos contribuindo para o avanço biotecnológico levando a descobertas de novas estruturas moleculares principalmente as derivadas da amida. A pesquisa biotecnológica aqui proposta utiliza o metabolismo de microrganismos como fungos e bactérias como principal mecanismo biotecnológico associado a sedimento manguezal exudado de petróleo e co-produtos glicerina e residual de mamona. Neste sentido, foi realizado um estudo de prospecção tecnológica no banco de dados Web of Science – Espacenet, por códigos indexados na Classificação Internacional De Patentes (CIP), que mostraram boas perspectivas em relação ao uso de microorganismos para a produção de moléculas de amida envolvendo reações enzimáticas inibidoras de uso na indústria farmacêutica para produção de produtos cosméticos e medicamentos

    Use Of Different Electrical Stimulations For Treating Pain In Women With Temporomandibular Disorders [utilização De Diferentes Estimulações Elétricas Para O Tratamento Da Dor Em Mulheres Com Disfunção Temporomandibular]

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    Objective: To analyze pain intensity in individuals with temporomandibular disorder (TMD) who were treated with ten sessions of transcutaneous electrical nerve stimulation (TENS) or high voltage electrical stimulation (HVES). Methods: Twenty-four women (22.98±1.86 years old) with a diagnosis of TMD in accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were selected. Sixty percent of the participants had a diagnosis of TMD classified as group Ia and 40% as Ia and IIa. They were divided into two groups named TENS group (TG) and high-voltage group (HVG). Each participant received ten applications of either TENS (10Hz, modulated at 50%, 200μs and motor threshold intensity) or HVES (10Hz, twin pulses of 20μs each at intervals of 100μs between the twin pulses, 100volts and positive pole) twice a week for 30 minutes. To measure the pain intensity, a visual analog scale (VAS) was used. Statistical analyses were performed using t test and simple linear regression. Results: Comparison of the pre- and post-TENS conditions showed diminished pain intensity (p<0.05) in most sessions except for sessions 6, 7 and 8. In contrast, HVES reduced the pain intensity in all sessions (p<0.05). Evaluation of the pre-application values showed that both treatments decreased the pain intensity uniformly over the ten sessions (p<0.05). Conclusions: TENS and HVES both promoted reductions in pain intensity in women with TMD. 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