Caracterização estrutural da lignina da parede celular de Euterpe oleracea

This paper aimed to characterize the lignin in the cell wall of Euterpe oleracea Mart. Samples from two regions of the base of the palm were acquired: outer and inner regions (OR and IR, respectively). The extraction with organic solvents and the treatment with 1% NaOH were carried out. Holocellulose, α-cellulose and lignin content were quantified, the latter also isolated by the Björkman method for the structural characterization using 1H and 13C NMR in the liquid state, as well as spectroscopic (FTIR) and chromatographic analysis. The extracted stem had 10.33% (OR) and 15.66% (IR) of the lignin. After the treatment with 1% NaOH, a reduction in these values was observed, and it was also possible to confirm this result through the decrease in the intensities of the signals referring to the functional groups linked to lignin and hemicellulose. The spectroscopic and chromatographic analyzes revealed GS-type lignin incorporated with p-hydroxybenzoic and protocatechuic acid in both samples. The main structural units present in the lignin were also observed, such as β-O-4 bond, β-O-4’ ϒ-acetyl bond, guaiacyl unit, syringyl unit and p-hydroxybenzoate.Este trabalho teve como objetivo caracterizar a lignina na parede celular de Euterpe oleracea Mart. Foram adquiridas amostras de duas regiões da base da palmeira: região externa e região interna (OR e IR, respectivamente). A extração com solventes orgânicos e o tratamento com NaOH 1% foram realizados. O conteúdo de holocelulose, α-celulose e lignina foi quantificado, esta última também isolada pelo método de Björkman para a caracterização estrutural utilizando RMN de 1H e 13C no estado líquido, assim como análises espectroscópicas (FTIR) e cromatográficas. O caule extraído apresentou 10,33% (OR) e 15,66% (IR) de lignina. Após tratamento com NaOH 1%, observou-se uma redução desses valores, e foi possível confirmar esse resultado também através da diminuição nas intensidades dos sinais referentes aos grupos funcionais ligados à lignina e hemicelulose. As análises espectroscópicas e cromatográficas revelaram lignina do tipo GS incorporada com ácido p-hidroxibenzoico e protocatecuico em ambas as amostras. Também foram observadas as principais unidades estruturais presentes na lignina como ligação β-O-4, β-O-4’ ϒ-acetiladas, spiro-dienona, unidade guaiacila, unidade siringila e p-hidroxibenzoato

VARIAÇÃO INTRAESPECÍFICA NA ANATOMIA DO LENHO DE Hevea brasiliensis (Willd. ex A. Juss.) Mull. Arg. RELACIONADA À EXTRAÇÃO DE LÁTEX

Neste trabalho, foi estudada a influência da exploração do látex na anatomia do lenho de seringueiras nativas. Avaliou-se a hipótese de que as características anatômicas são afetadas pela atividade de extração do látex. Para isso, foram coletadas, de forma não-destrutiva, amostras em árvores nativas exploradas e não exploradas. As coletas foram feitas na Reserva Experimental de Catuaba, localizada em Senador Guiomard (AC). A estrutura anatômica do lenho foi analisada, sendo avaliados: o comprimento das fibras (não-gelatinosas e gelatinosas); diâmetro total e diâmetro do lume de fibras não-gelatinosas; diâmetro e frequência dos elementos de vaso; largura, altura e frequência de raios; e a proporção de tecidos. Árvores exploradas e não-exploradas diferiram na estrutura anatômica em relação às características quantitativas. Apenas as variáveis comprimento de fibra gelatinosa, diâmetro do lume das fibras, frequência de raios e proporção de elementos de vaso e raios não apresentaram diferenças significativas pelo teste de Mann-Whitney. Os resultados mais contundentes consistiram em aumento da largura e altura de raios nas árvores extraídas, bem como maiores proporções de fibras gelatinosas nas árvores não-extraídas. As diferenças observadas entre os grupos avaliados podem ser atribuídas à demanda de carboidratos que a regeneração do fluxo de látex ocasiona nesses indivíduos. Recomendam-se maiores estudos acerca do consumo de carboidratos não-estruturais, relacionados diretamente às mudanças na estrutura do xilema de seringueira

O clickbait no ciberjornalismo português e brasileiro: o caso brasileiro

O trabalho tem como proposta analisar a incidência de "clickbait" no jornalismo online português e brasileiro. Faz parte de uma atividade realizada em conjunto por pesquisadores brasileiros e portugueses, em que cada grupo efetuou a verificação em 18 veículos de informação geral do seu país com abrangência nacional, com produção própria e atualizada frequentemente, tanto nas páginas Web, assim como no Facebook. Este artigo traz os resultados encontrados na amostra brasileira que apontam um alto índice de "clickbait" ao se verificar os dados gerais, com 54,4% da amostra com ocorrência desta prática. Ao mesmo tempo, os valores se reduzem ao olharmos os 32 indicadores individualmente, em que apenas três tiveram índices superiores a 10%.The paper aims to analyze the incidence of clickbait in Portuguese and Brazilian online journalism. It is part of an activity carried out jointly by Brazilian and Portuguese researchers, in which each group carried out the verification in the Web and Facebook pages of 18 general information vehicles of such countries, each having national coverage, as well as its own production and frequent updates. This article presents the results found in the Brazilian sample that shows a high clickbait index, of 54.4%, when crosschecking the general data. On the other hand, the values are reduced when we look at the 32 indicators individually, in which only three had rates above 10%

O clickbait no ciberjornalismo português e brasileiro: o caso português

A investigação que aqui se apresenta partiu da proposta de analisar a incidência de clickbait no ciberjornalismo português e brasileiro. Faz parte de um projeto desenvolvido em conjunto por investigadores brasileiros e portugueses, em que cada grupo efetuou a verificação em 18 cibermeios de informação geral do seu país com abrangência nacional e com produção própria e atualizada frequentemente, tanto nas páginas Web como no Facebook. Neste artigo apresentamos os resultados encontrados nos 270 títulos/conteúdos que constituíram a amostra portuguesa, que apontam para um índice de clickbait de 39,6%. Analisando individualmente os 32 indicadores, verificamos que nenhum chega aos 10%, destacando-se como valor mais alto a "Informação empolada", presente em 8,5% da amostra.The paper aims to analyze the incidence of clickbait in Portuguese and Brazilian online journalism. It is part of an activity carried out jointly by Brazilian and Portuguese researchers, in which each group carried out the verification in the Web and Facebook pages of 18 general information vehicles of such countries, each having national coverage, as well as its own production and frequent updates. This article presents the results found in the Portuguese sample that shows a high clickbait index, of 39,6%, when cross-checking the general data. On the other hand, the values are reduced when we look at the 32 indicators individually, all of them with rates below 10%

“Quem ensina também aprende” : a formação pela prática de professores primários na província do Paraná

Resumo Segundo a historiografia da educação brasileira, muitas foram as ações relacionadas aos modos de formar professores primários durante o período imperial. Desses estudos, a maioria se centra na formação de professores atrelada à instituição das escolas normais, entretanto, há uma parcela menor de trabalhos que se propõem a discutir outro aspecto da formação de professores ao longo do século XIX, mais especificamente, a forma como sujeitos que não frequentaram esse espaço institucional (a escola normal), constituíram-se docentes primários. O artigo que aqui se apresenta partilha dessa perspectiva, e volta o olhar para os modos de formação pela prática de professores primários no Paraná na segunda metade do século XIX, por compreender que esse tipo de formação marcou um período em que a instrução pública estava se consolidando em meio a ações, deliberações, dificuldades e tensões, na tentativa de melhorias de sua condição. A pesquisa valeu-se da consulta da legislação educacional do período e de documentos advindos dos sujeitos envolvidos com a instrução pública, naquele momento, disponíveis no acervo do Arquivo Público do Paraná. No cotejamento e análise das fontes, é possível afirmar, que a formação pela prática dos professores primários na província do Paraná se deu no decorrer do desenvolvimento do processo de constituição do magistério primário

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit