Dust content solutions for the Alcubierre warp drive spacetime

The Alcubierre metric is a spacetime geometry where a massive particle inside a spacetime distortion, called warp bubble, is able to travel at velocities arbitrarily higher than the velocity of light, a feature known as the warp drive. This is a consequence of general relativity, which allows global superluminal velocities but restricts local speeds to subluminal ones as required by special relativity. In this work we solved the Einstein equations for the Alcubierre warp drive spacetime geometry considering the dust matter distribution as source, since the Alcubierre metric was not originally advanced as a solution of the Einstein equations, but as a spacetime geometry proposed without a source gravity field. We found out that all Einstein equations solutions of this geometry containing pressureless dust lead to vacuum solutions. We also concluded that these solutions connect the Alcubierre metric to the Burgers equation, which describes shock waves moving through an inviscid fluid. Our results also indicated that these shock waves behave as plane waves.Comment: 15 pages, 1 figure. LaTeX. Accepted for publication in the European Physical Journal

The Influence of Performance Level, Age and Gender on Pacing Strategy During a 100-km Ultramarathon

The aim of this study is to analyse the influence of performance level, age and gender on pacing during a 100-km ultramarathon. Results of a 100-km race incorporating the World Masters Championships were used to identify differences in relative speeds in each 10-km segment between participants finishing in the first, second, third and fourth quartiles of overall positions (Groups 1, 2, 3 and 4, respectively). Similar analyses were performed between the top and bottom 50% of finishers in each age category, as well as within male and female categories. Pacing varied between athletes achieving different absolute performance levels. Group 1 ran at significantly lower relative speeds than all other groups in the first three 10-km segments (all P < 0.01), and significantly higher relative speeds than Group 4 in the 6th and 10th (both P < 0.01), and Group 2 in the 8th (P = 0.04). Group 4 displayed significantly higher relative speeds than Group 2 and 3 in the first three segments (all P < 0.01). Overall strategies remained consistent across age categories, although a similar phenomenon was observed within each category whereby ‘top’ competitors displayed lower relative speeds than ‘bottom’ competitors in the early stages, but higher relative speeds in the later stages. Females showed lower relative starting speeds and higher finishing speeds than males. ‘Top’ and ‘bottom’ finishing males displayed differing strategies, but this was not the case within females. Although pacing remained consistent across age categories, it differed with level of performance within each, possibly suggesting strategies are anchored on direct competitors. Strategy differs between genders and differs depending on performance level achieved in males but not females

Blog Química Sustentável – Por uma Educação Ambiental promotora de sustentabilidade

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DESENVOLVIMENTO DE PELLETS CONTENDO AGREGADOS DE HIFAS DE METARHIZIUM ANISOPLIAE PARA CONTROLE BIOLÓGICO DE ARTRÓPODES

ntrodu&ccedil;&atilde;o e objetivos: Artr&oacute;podes s&atilde;o respons&aacute;veis por s&eacute;rios danos a agricultura e a sa&uacute;de humana e animal, causando expressivos preju&iacute;zos &agrave; economia brasileira1. M&eacute;todos de controle biol&oacute;gico de tais artr&oacute;podes est&atilde;o sendo desenvolvidos com a utiliza&ccedil;&atilde;o de prop&aacute;gulos do fungo Metarhizium anisopliae2,3. O objetivo do presente trabalho foi desenvolver pellets contendo agregados de hifas de M. anisopliae CG 47, e avaliar sua viabilidade p&oacute;s-processamento. Metodologia: Os agregados de hifas foram obtidos atrav&eacute;s da inocula&ccedil;&atilde;o de con&iacute;dios em meio descrito por Mascarin et al. (2014)4, seguido de incuba&ccedil;&atilde;o orbital por 4 dias, a 27&ordm;C e 250 rpm. Os pellets foram desenvolvidos utilizando-se celulose microcristalina e biomassa (1:1,1, p/v) atrav&eacute;s da t&eacute;cnica de extrus&atilde;o-esferoniza&ccedil;&atilde;o, seguida de secagem em leito fluidizado a 40&ordm;C. A umidade residual dos pellets foi determinada em balan&ccedil;a de infravermelho. A viabilidade foi determinada incubando-se 30 mg de pellets em meio &aacute;gar-&aacute;gua, a 27&ordm;C por 15 dias, e a germina&ccedil;&atilde;o dos con&iacute;dios resultantes foi quantificada ap&oacute;s 48h de incuba&ccedil;&atilde;o em meio BDAY. Resultados e discuss&atilde;o: Os pellets apresentaram umidade residual de 5,3% ap&oacute;s 90 minutos de secagem em leito fluidizado. A viabilidade dos con&iacute;dios foi de 96,67%. Conclus&otilde;es: Os con&iacute;dios produzidos a partir dos agregados de hifas mantiveram-se vi&aacute;veis ap&oacute;s sua incorpora&ccedil;&atilde;o em pellets de celulose e secagem por 90 minutos a 40&ordm;C; dessa forma, permite-se inferir que foi estabelecida uma metodologia eficiente para formula&ccedil;&atilde;o de um prop&aacute;gulo de M. anisopliae que apresenta potencial para controle biol&oacute;gico de artr&oacute;podes. Agradecimentos: Conselho Nacional de Desenvolvimento Cient&iacute;fico e Tecnol&oacute;gico (CNPq), Coordena&ccedil;&atilde;o de Aperfei&ccedil;oamento de Pessoal de N&iacute;vel Superior (CAPES)

A strategy for the rapid identification of fungal metabolites and the discovery of the antiviral activity of pyrenocine a and harzianopyridon

The isolation and identification of bioactive metabolites from complex extracts obtained from microbial growth media is a time consuming, costly, and labor-intensive task. A strategy to rapidly identify secondary metabolites isolated from extracts obtained from the culture media of marine-derived and endophytic fungal strains is described. Identification was achieved by HPLC-UV-MS and 1H NMR analyses in combination with data obtained from the Dictionary of Natural Products. Among the compounds identified, (-)-naphthoquinoneimine, citreorosein, emodin, pyrenocine A and harzianopyridone displayed moderate to potent antiviral activity. (-)-Naphthoquinoneimine was isolated as the enantiomer of its previously reported dextrorotatory congener, while 6,7-dihydroxy-2,2-dimethyl-4-chromanone is herein reported for the first time as a natural product396720731CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPBEX 4498-14-32010/50190-2; 2013/50228-8; 2011/08064-2; 2008/00331-9; 2013/23153-

Optimal Cutoff Scores for Dementia and Mild Cognitive Impairment in the Brazilian Version of the Montreal Cognitive Assessment among the Elderly

Objective: To propose cutoff scores for the Brazilian version of the Montreal Cognitive Assessment (MoCA-BR) stratified by education in order to detect mild cognitive impairment (MCI) and mild Alzheimer’s disease (AD) in the elderly. Method: A transversal study in health centers was performed on 159 elderly people with 4–12 years of education and 70 of their peers with over 12 years of schooling. The MoCA-BR cutoff scores for screening cognitive impairment were determined based on an ROC curve analysis. Results: The ROC curve analysis indicated that cutoff scores under 20 were good for screening elderly people with cognitive impairment with more than 12 years of education, and scores under 21 were good for screening those with 4–12 years of education. Conclusions: MoCA-BR scores under 21 points (after adding 1 point to the elderly with ≤12 years of education) indicate a need to continue the diagnostic investigation with regular follow-ups

Mortality inequalities measured by socioeconomic indicators in Brazil: a scoping review

OBJECTIVE Summarize the literature on the relationship between composite socioeconomic indicators and mortality in different geographical areas of Brazil. METHODS This scoping review included articles published between January 1, 2000, and August 31, 2020, retrieved by means of a bibliographic search carried out in the Medline, Scopus, Web of Science, and Lilacs databases. Studies reporting on the association between composite socioeconomic indicators and all-cause, or specific cause of death in any age group in different geographical areas were selected. The review summarized the measures constructed, their associations with the outcomes, and potential study limitations. RESULTS Of the 77 full texts that met the inclusion criteria, the study reviewed 24. The area level of composite socioeconomic indicators analyzed comprised municipalities (n = 6), districts (n = 5), census tracts (n = 4), state (n = 2), country (n = 2), and other areas (n = 5). Six studies used composite socioeconomic indicators such as the Human Development Index, Gross Domestic Product, and the Gini Index; the remaining 18 papers created their own socioeconomic measures based on sociodemographic and health indicators. Socioeconomic status was inversely associated with higher rates of all-cause mortality, external cause mortality, suicide, homicide, fetal and infant mortality, respiratory and circulatory diseases, stroke, infectious and parasitic diseases, malnutrition, gastroenteritis, and oropharyngeal cancer. Higher mortality rates due to colorectal cancer, leukemia, a general group of neoplasms, traffic accident, and suicide, in turn, were observed in less deprived areas and/or those with more significant socioeconomic development. Underreporting of death and differences in mortality coverage in Brazilian areas were cited as the main limitation. CONCLUSIONS Studies analyzed mortality inequalities in different geographical areas by means of composite socioeconomic indicators, showing that the association directions vary according to the mortality outcome. But studies on all-cause mortality and at the census tract level remain scarce. The results may guide the development of new composite socioeconomic indicators for use in mortality inequality analysis