ABSTRACT Hydrogen peroxide (H2O2) can be indicated as a strategy to mitigate salt stress in plants, so the objective of this study was to evaluate the effect of different concentrations and methods of application of H2O2 as a mitigator of salt stress on the growth, physiology, and quality of seedlings of yellow passion fruit. The experiment was carried out in a protected environment (screened) belonging to UFERSA, in Caraúbas - RN, Brazil, in a randomized block design and analyzed in a 2 × 4 × 3 factorial scheme, with four replications and one plant per plot. The treatments consisted of levels of electrical conductivity of irrigation water - ECw (0.5 and 3.2 dS m-1), H2O2 concentrations (0, 12, 24, and 36 μM), and H2O2 application methods (M1 = seed soaking, M2 = foliar spraying, and M3 = seed soaking + foliar spraying). Increased levels of salinity in irrigation water negatively affect seedling quality. Hydrogen peroxide at an average concentration of 24 µM mitigates salt stress in passion fruit seedlings cv. BRS Gigante Amarelo. H2O2 application to seeds associated with foliar spraying mitigates the effects of salt stress on the absolute growth rate of the leaf area of passion fruit seedlings irrigated with an ECw of 3.2 dS m-1.

RESUMO O peróxido de hidrogênio (H2O2) pode ser indicado como uma estratégia para mitigar o estresse salino em plantas, por isso o objetivo deste estudo foi avaliar os efeitos das concentrações e métodos de aplicação de H2O2 como mitigador do estresse salino sobre o crescimento, fisiologia e qualidade de mudas de maracujá cv. BRS Gigante Amarelo. O experimento foi conduzido em ambiente protegido (telado) pertencente a UFERSA, em Caraúbas - RN, Brasil, em delineamento em blocos casualizados e analisados em esquema fatorial 2 × 4 × 3, com quatro repetições e uma planta por parcela. Os tratamentos consistiram em: condutividade elétrica da água de irrigação - CEa (0,5 e 3,2 dS m-1); concentrações de H2O2 (0, 12, 24 e 36 μM); e métodos de aplicação de H2O2 (M1 = embebição das sementes, M2 = pulverização foliar e M3 = embebição das sementes + pulverização foliar). O aumento dos níveis de salinidade da água de irrigação afeta negativamente a qualidade das mudas. O peróxido de hidrogênio na concentração de 24 µM mitiga o estresse salino em mudas de maracujazeiro cv. BRS Gigante Amarelo. A aplicação de H2O2 em sementes associada à pulverização foliar mitiga os efeitos do estresse salino sobre a taxa de crescimento absoluto da área foliar de mudas de maracujá irrigadas com CEa de 3,2 dS m-1.

Abstract Introduction The Cognitive Distortions Questionnaire (CD-Quest) is an instrument that identifies logical errors or cognitive distortions and is used in trial-based cognitive therapy (TBCT). However, it had previously only been available for adults. Objectives To develop and validate a version of the CD-Quest for teens (CD-Quest-T) aged 11 to 17 years and test its psychometric properties. Method A total of 299 schoolchildren participated in the investigation. After content validity was assessed, the language was adapted for the target age group, and the length of the instrument was reduced to eight items (from the initial 15). Five cognitive therapists analyzed the content and structure of the items. Finally, to investigate the construct validity of the CD-Quest-T, the instrument was divided into a full scale and two subscales, which measure the frequency of the distortions and the intensity attributed to them, respectively. Results The overall internal consistency of the scale was α = 0.77, whereas subscale indices were α = 0.75 for the frequency scale and α = 0.73 for the intensity scale. Results from exploratory factor analysis and concurrent validity analysis indicated that the CD-Quest-T items have good psychometric properties and generate scores reliably. Conclusion The psychometric properties of the CD-Quest-T demonstrate its adequacy for measurement of cognitive distortions in adolescents.

Abstract Ganoderma lucidum is a medicinal mushroom widely recognized as a source of biomolecules with pharmacological properties, however, little is known about the factors that influence the synthesis of bioactive proteins by this fungus when cultivated under submerged fermentation. The objective of this work was to evaluate the production of mycelial biomass and intracellular proteases and protease inhibitors by G. lucidum cultivated under different submerged fermentation conditions. The cultivation was carried out in a medium composed of glucose (10 or 20 g.L-1), soy peptone (2.5 or 5 g.L-1) and yeast extract (5 g.L-1), with incubation under agitation (120 rpm) and non-agitation, totaling 8 experimental conditions. Biomass production was determined from the dry weight, while glucose consumption was estimated by quantification of reducing sugars. The proteins were extracted in NaCl (0.15 M), and the protein extracts were submitted to protein quantification by the Bradford method, total proteolytic activity using azocasein, caseinolytic and fibrinolytic activity in Petri dishes, activity of serine (trypsin and chymotrypsin) and cysteine (papain) protease inhibitors. Cultivation in agitated condition showed higher biomass production with a maximum value of 7 g.L-1, in addition to higher activities of trypsin, chymotrypsin and papain inhibitors, with 154 IU.mg-1, 153 IU.mg-1 e 343 IU.mg-1 of protein, respectively. The non-agitated condition showed a greater potential for obtaining proteins, total proteases, caseinolytic and fibrinolytic enzymes, with maximum values of 433 mg.g-1 of extract, 71 U.mL-1 of extract, 63.62 mm2 and 50.27 mm2, respectively. Thus, a medium composed of soy peptone, yest extract and glucose in a 1:2:4 proportion is recommended, under agitation to produce protease inhibitors, and the non-agitated condition when the target is, mainly caseinolytic and fibrinolytic enzymes.

Resumo Ganoderma lucidum é um cogumelo medicinal amplamente reconhecido como fonte de biomoléculas com propriedades farmacológicas, entretanto, pouco se conhece acerca dos fatores que influenciam a síntese de proteínas bioativas por esse fungo, quando cultivado sob fermentação submersa. O objetivo deste trabalho foi avaliar a produção de biomassa micelial e de proteases e inibidores de proteases intracelulares por G. lucidum cultivado em diferentes condições de fermentação submersa. O cultivo foi realizado em meio contendo glicose (10 ou 20 g.L-1), peptona de soja (2,5 ou 5 g.L-1) e extrato de levedura (5 g.L-1), com incubação sob agitação (120 rpm) ou não-agitado, totalizando 8 condições experimentais. A produção de biomassa foi determinada a partir do peso seco e o consumo de glicose a partir da quantificação de açúcares redutores. As proteínas foram extraídas em NaCl (0,15 M) e os extratos proteicos foram submetidos à quantificação de proteínas pelo método de Bradford, atividade proteolítica total usando azocaseína, atividade caseinolítica e fibrinolítica em placa de Petri, atividade de inibidores de serino-proteases (tripsina e quimotripsina) e cisteíno-protease (papaína). O cultivo em condição agitada apresentou maior produção de biomassa com valor máximo de 7g.L-1, além de maiores atividades de inibidores de tripsina, quimotripsina e papaína, com 154 UI.mg-1, 153 UI.mg-1 e 343 UI.mg-1 de proteína, respectivamente. A condição não-agitada demonstrou maior potencial para a obtenção de proteínas, proteases totais, enzimas caseinolíticas e fibrinolíticas, com valores máximos de 433 mg.g-1 de extrato, 71 U.mL-1 de extrato, 63,62 mm2 e 50,27 mm2, respectivamente. Assim, recomenda-se o meio composto de peptona de soja, extrato de levedura e glicose na proporção 1:2:4, em condição agitada para a produção de inibidores de proteases, e a condição não-agitada para a síntese de proteases, principalmente enzimas caseinolíticas e fibrinolíticas.

Abstract Different degrees in the biological activities of Canavalia rosea had been previously reported . In this study, our group assessed the cardioprotective effects of the ethyl acetate fraction (EAcF) of the Canavalia rosea leaves. Firstly, it was confirmed, by in vitro approach, that the EAcF has high antioxidant properties due to the presence of important secondary metabolites, as flavonoids. In order to explore their potential protector against cardiovascular disorders, hearts were previously perfused with EAcF (300 μg.mL-1) and submitted to the global ischemia followed by reperfusion in Langendorff system. The present findings have demonstrated that EAcF restored the left ventricular developed pressure and decreased the arrhythmias severity index. Furthermore, EAcF significantly increased the glutathiones peroxidase activity with decreased malondialdehyde and creatine kinase levels. EAcF was effective upon neither the superoxide dismutase, glutationes reductase nor the catalase activities. In addition, the Western blot analysis revealed that ischemia-reperfusion injury significantly upregulates caspase 3 protein expression, while EAcF abolishes this effect. These results provide evidence that the EAcF reestablishes the cardiac contractility and prevents arrhythmias; it is suggested that EAcF could be used to reduce injury caused by cardiac reperfusion. However more clinical studies should be performed, before applying it in the clinic.

Abstract Several studies have been conducted evaluating the management of fertilizers as strategies to mitigate the deleterious effects of salt stress, so the objective of this work was to evaluate the quality of ‘Crioula’ guava seedlings under irrigation with water of different salinity levels and fertilized with combinations of nitrogen and potassium. The experiment was performed in a protected (screened) environment using a randomized block design and analyzed in a 5 × 4 factorial scheme, with four replicates, with the plot formed by two plants. The treatments were formed from the combination of the factor electrical conductivity of irrigation water (ECw 0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1), with the factor combinations (C) of nitrogen (N) and potassium (K2O) doses, being C1 = 70% N + 50% K2O, C2 = 100% N + 75% K2O, C3= 130% N + 100% K2O and C4= 160% N + 125% K2O. The recommended dose of 100% N and K, respectively, was 541.1 mg N dm-3 soil and 798.6 mg K dm-3 soil. The combinations of N and K fertilization corresponding to 70% N + 50% K2O and 100% N + 75% K2O of the recommended doses promoted greater growth of ‘Crioula’ guava seedlings. Water with ECw of 2.1 dS m-1 promotes the formation of quality ‘Crioula’ guava seedlings.

Resumo Diversos estudos vêm sendo desenvolvido avaliando o manejo de adubos como estratégias para mitigar os efeitos deletérios do estresse salino, neste sentido, objetivou-se com este trabalho avaliar a qualidade de mudas de goiabeira Crioula sob irrigação com águas de diferentes níveis salinos e adubadas com combinações de nitrogênio e potássio. O experimento foi conduzido em ambiente protegido (telado) utilizando-se o delineamento de blocos casualizados e analisados em esquema fatorial 5 × 4, com quatro repetições, com a parcela formada por duas plantas. Os tratamentos foram formados pela combinação do fator condutividade elétrica da água de irrigação (CEa), com valores de 0,3; 1,1; 1,9; 2,7 e 3,5 dS m-1; e o fator combinações (C) de doses de nitrogênio (N) e potássio (K2O), sendo C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3= 130% N + 100% K2O e C4= 160% N + 125% K2O. A dose recomendada de 100% de N e K, respectivamente, foi de 541,1 e 798,6 mg de K dm-3 de solo. As combinações de adubação nitrogenada e potássica de 70% N + 50% K2O e 100% N + 75% K2O, em relação às doses recomendadas, resultaram em um maior crescimento de mudas de goiabeira Crioula. Água com CEa média de 2,1 dS m-1 foi capaz de promove a formação de mudas de qualidade de goiabeira Crioula.

ABSTRACT Syndemic psychosocial and reproductive factors affecting women’s retention in HIV care remain understudied. We analyzed correlates of non-retention in a cohort of women with HIV in Brazil from 2000–2015. Participants self-reported exposure to physical/sexual violence, illicit drug use, adolescent pregnancy, or induced abortion. Lifetime history of these psychosocial stressors were used to create a syndemic score based on the presence or absence of these conditions. All dichotomous variables were summed (range 0 to 4), with greater scores indicating more syndemic factors experienced. Logistic regression models identified predictors of non-retention, defined as < 2 HIV viral load or CD4 results within the first year of enrollment. Of 915 women, non-retention was observed for 18%. Prevalence of syndemic factors was adolescent pregnancy (53.2%), physical/sexual violence (38.3%), induced abortion (27.3%), and illicit drug use (17.2%); 41.2% experienced > 2 syndemic conditions. Syndemic scores of 2 and 3 were associated with non-retention, as well as low education, years with HIV and seroprevalent syphilis. Psychosocial and reproductive syndemics can limit women’s retention in HIV care. Syphilis infection predicted non-retention and could be explored as a syndemic factor in future studies.

Neste trabalho, apresentaremos experimentos portáteis no intuito de abordar os conceitos da indução eletromagnética com alunos do Ensino Básico. Os materiais utilizados para a realização dos experimentos são de fácil aquisição e o conjunto deles pode ser adquirido na forma de um kit, facilmente transportável. A proposta é que os alunos aprendam os conceitos por meio de discussão em sala e da execução de experimentos. Para isso, será dado maior destaque às aulas interativas em detrimento das expositivas. Assim, nos inspiramos na metodologia desenvolvida pelo grupo da Universidade de Rutgers, liderado pela professora Eugenia Etkina. A fundamentação dessa proposta é que os alunos estudem e aprendam os conceitos físicos de forma semelhante à forma que os cientistas trabalham para construir o conhecimento científico. Tal metodologia foi denominada “Investigative Science Learning Environment” (ISLE). Desta feita, os alunos são apresentados ao método científico, ainda no Ensino Médio, de forma concreta, em que a observação, a proposição e a refutação de hipóteses são fundamentais para a criação de um modelo para o fenômeno físico estudado. Para avaliar a metodologia e os experimentos portáteis, apresentamos uma proposta de sequência didática a ser aplicada em uma turma da terceira śerie do Ensino Médio.

In this paper we will present a portables experiments in order to approach the concepts of electromagnetic induction to Basic Education students. The materials used to perform the experiments are easy to acquire, and the set of them can be purchased in the form of an experimental kit, easily transportable. The proposal is that students learn the concepts through classroom discussion and the execution of experiments, with greater emphasis on interactive classes over lectures. For this, we were inspired by the methodology developed by the group from Rutgers University, led by Professor Eugenia Etkina. The foundation of this proposal is that student’s study and learn physical concepts similar to the way scientists work to setup scientific knowledge. Such methodology was called “Investigative Science Learning Environment” (ISLE). In this method, students are introduced to the scientific method, in high school, in a concrete way where observation, proposition and refutation of hypotheses are fundamental for creating a model for the physical phenomenon studied. To evaluate the methodology and use of the portable experiment, we present a proposal for a didactic sequence to be applied to a twelve-year high school class.

Resumo Shewanella xiamenensis G5-03 foi capaz de descolorir o corante azo vermelho Congo em água residuária sintética. A influência de alguns fatores na eficiência da descoloração do corante foi avaliada. As condições ótimas de descoloração foram temperatura de 30-35 °C, pH 10,0 e condições estáticas. A cinética de descoloração do vermelho Congo se ajustou ao modelo de Michaelis–Menten (Vmax = 111,11 mg L-1 h-1 and Km = 448,3 mg L-1). A bactéria também foi capaz de degradar a benzidina, um produto da quebra da ligação azo do vermelho Congo, o que contribuiu para a redução da fitotoxicidade. A habilidade da S. xiamenensis G5-03 em simultaneamente descolorir e degradar o vermelho Congo demostra seu potencial de aplicação no tratamento de águas residuárias contendo corantes azo.

Abstract Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on the dye decolorization efficiency was evaluated. The optimal decolorization conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. The kinetic of Congo red decolorization fitted to the Michaelis–Menten model (Vmax = 111.11 mg L-1 h-1 and Km = 448.3 mg L-1). The bacterium was also able to degrade benzidine, a product of azo bond breakage of the Congo red, which contributed to reduce the phytotoxicity. The ability of S. xiamenensis G5-03 for simultaneous decolorization and degradation of Congo red shows its potential application for the biological treatment of wastewaters containing azo dyes.

ABSTRACT We propose a compartmental SIRD model with time-dependent parameters that can be used to give epidemiological interpretations to the phenomenological parameters of the Richards growth model. We illustrate the use of the map between these two models by fitting the fatality curves of the COVID-19 epidemic data in Italy, Germany, Sweden, Netherlands, Cuba, and Japan, up to July 30, 2020.

This work describes the first determination of the absolute configuration (AC) of (−)-cubebin by means of electronic circular dichroism (ECD), supported by quantum chemical calculations. The comparison of experimental ECD with the corresponding quantum chemical prediction for the proper diastereoisomer resulted in the definitive assignment of the AC of the naturally occurring (−)-cubebin as (8R,8aR,9S). The challenging determination of the relative configuration (RC) of cubebin based only on experimental nuclear magnetic resonance (NMR) methods is stressed. Computation of the 13C and 1H NMR chemical shifts for all the possible diastereoisomers leads to values of mean absolute error and root mean square deviation that do not allow distinguishing among them. Thus, errors in stereochemical determination can easily occur even when using two-dimensional methods, which clearly demonstrate the complexity of this special case. To determine the RC of this bioactive natural compound with high level of confidence, it was necessary to combine the DP4+ method with X-ray crystallography. Therefore, employing the commonly used empirical methods to determine the AC of (−)-cubebin can easily lead to misassignment of its stereochemistry.

In this Technical Note we analyze the cumulative curves of deaths attributed to Covid-19 in the 26 Brazilian states and the Federal District until August 21, 2020. Mathematical growth models implemented by the ModInterv Covid-19 application, which can be accessed via internet browser or via a mobile app available at the Google Play Store, were used to investigate at which stage the epidemic is in each of these entities of the Federation. The analysis revealed that almost all states in the Northern and Northeastern regions are in the saturation phase, when the epidemic is relatively under control, while in all Southern states and in most states in the Midwest the epidemic is still accelerating or shows only a slight deceleration. The Southeastern region presents a great diversity of epidemic stages, with each state at a different stage, ranging from acceleration to saturation.

Nesta Nota Técnica nós analisamos as curvas acumuladas de mortes atribuídas à Covid-19 nos 26 estados e Distrito Federal até o dia 21 de agosto de 2020. Foram utilizados modelos matemáticos de crescimento implementados pelo aplicativo ModInterv Covid-19, que pode ser acessado via internet (http://fisica.ufpr.br/modinterv) ou através de aplicativo para celular disponível na Play Store (https://play.google.com/store/apps/details?id=com.tanxe.covid_19), para investigar em qual fase da epidemia cada um dessas unidades da federação se encontra. A análise revelou que quase todos os estados das Regiões Norte e Nordeste encontram-se em uma fase de saturação, quando a epidemia está relativamente sob controle, ao passo que em todos os estados do Sul e a maioria dos estados do Centro-Oeste a epidemia ainda está em aceleração ou apresenta apenas uma leve desaceleração. A Região Sudeste apresenta uma grande diversidade de estágios da epidemia, com cada estado em um estágio diferente, indo de acelerado à saturação.

In this technical note we analyze the accumulated fatality curves attributed to Covid-19 in the 27 Brazilian state capitals until July 19, 2020. We employed three mathematical growth models to assess at which stage of the epidemic each of these cities is at. These models were implemented in the Modinterv Covid-19 application, developed by the Federal Universities of Paraná, Pernambuco and Sergipe, which can be accessed through the &lt;http://fisica.ufpr.br/modinterv&gt; page. The analysis reveals that only Recife and Belém appear to have reached the saturation phase of the epidemic, when the accumulated fatality curve begins to approach the plateau. Among the other capitals, eight are still in the initial phase of rapid growth and seventeen are in the intermediate phase, when the epidemic curve has already passed through the inflection point but is still relatively far from the plateau.

Nessa nota técnica analisamos as curvas acumuladas de mortes atribuídas à Covid-19 nas 27 capitais brasileiras até o dia 19 de julho de 2020. Empregamos três modelos matemáticos de crescimento para avaliar em que fase da epidemia encontra-se cada uma dessas cidades. Esses modelos&nbsp; foram implementados&nbsp; no aplicativo Modinterv Covid-19, desenvolvido pelas Universidades Federais do Paraná, Pernambuco e Sergipe, o qual pode ser acessado através da página http://fisica.ufpr.br/modinterv. A análise revela que apenas Recife e Belém aparentam ter atingido a fase de saturação da epidemia, quando a curva acumulada de morte começa a se aproximar do platô. Entre as demais capitais, oito ainda estão na fase inicial de crescimento rápido e dezessete estão na fase intermediária, quando a curva epidêmica já passou pelo ponto de inflexão mas ainda está relativamente distante do platô.

The Covid-19 pandemic, caused by the new coronavirus (SARS-CoV-2), is one of the gravest public health crises the world has ever faced. In this context, it is important to have effective models to describe the different stages of the epidemic, in order to offer guidance to the competent authorities regarding the adoption of public policies to contain and control the pandemic. In this work, we present a novel method to analyze epidemic curves based on growth models, using as examples the cumulative curves of deaths attributed to Covid-19 for the states of the Northeastern Region of Brazil. Depending on the case, the q-exponential model, the Richards model or the generalized Richards model were used to make the numerical fits of the respective empirical curves. The models used here describe very well the empirical curves of all the Northeastern Brazilian States, thus allowing a more precise diagnosis of the stage of the epidemic in each of the States.  Among them, only the state of Paraíba is still in the early growth phase, when the epidemic curve does not yet have an inflexion point, being in this case better described by the q-exponential model.  The other states were better described either by the Richards model or by its generalized version. The Richards model, in particular, was able to identify with reasonable reliability the emergence of the inflexion point for states that only recently have reached this stage of the epidemic, such as Piauí, Rio Grande do Norte and Sergipe. This model is also able to predict when the inflection is about to occur, as is the case in Bahia. The generalized Richards model, in turn, has proved more appropriate to describe epidemic curves in states that are in a more developed phase of the epidemic, such as Ceará and Pernambuco, when the epidemic curves already show a more consolidated trend of saturation toward the plateau.

A pandemia da Covid-19, causada pelo novo coronavírus (SARS-CoV-2), é uma das maiores crises de saúde pública que o mundo já enfrentou. Nesse contexto, é importante ter modelos eficazes para descrever os diferentes estágios da evolução da epidemia, a fim de orientar as autoridades competentes na adoção de políticas públicas para o enfrentamento e controle da pandemia. No presente trabalho, nós propomos um novo método de análise de curvas epidêmicas com base na seleção criteriosa de modelos de crescimento, tomando como exemplo as curvas acumuladas de óbitos atribuídos à Covid-19 para os estados da região Nordeste do Brasil. A depender do caso, foram utilizados o modelo q-exponencial, o modelo de Richards ou o modelo generalizado de Richards para fazer o ajuste numérico das respectivas curvas empíricas. Verificou-se que os modelos utilizados descrevem muito bem as curvas empíricas de todos os estados do Nordeste, permitindo assim diagnosticar mais precisamente o estágio da epidemia em cada um dos estados. Dentre eles, apenas o estado da Paraíba ainda encontra-se na fase inicial de crescimento, quando a curva epidêmica ainda não apresenta um ponto de inflexão, sendo nesse caso melhor descrita pelo modelo q-exponencial. Os demais estados foram mais bem descritos ou pelo modelo de Richards ou por sua versão generalizada. O modelo de Richards, em particular, foi capaz de identificar com razoável confiabilidade o surgimento do ponto de inflexão para os estados que só recentemente alcançaram esse estágio da epidemia, como foi o caso do Piauí, Rio Grande do Norte e Sergipe. Esse modelo também é capaz de prever quando a inflexão está prestes a acontecer, como é o caso da Bahia. O modelo generalizado de Richards, por sua vez, mostrou-se mais apropriado para descrever curvas epidêmicas de estados que estão em uma fase mais desenvolvida da epidemia, como Ceará e Pernambuco, quando as curvas epidêmicas já apresentam uma tendência mais consolidada de saturação em direção ao platô.

Introduction: The Covid-19 pandemic is one of the biggest public health crises the world has ever faced. In this context, it is important to have effective models to describe the different stages of the epidemic’s evolution in order to guide the authorities in taking appropriate measures to fight the disease. Objective: To present an analysis of epidemic curves of Covid-19 based on phenomenological growth models, with applications to the curves for the cumulative numbers of confirmed cases of infection by the novel coronavirus (Sars-Cov-2) and deaths attributed to the disease (Covid-19) caused by the virus, for the Brazilian cities of Recife and Teresina. Methods: The Richards generalized model and the generalized growth model were used to make the numerical fits of the respective empirical curves. Results: The models used described very well the empirical curves against which they were tested. In particular, the generalized Richards model was able to identify the appearance of the inflexion point in the cumulative curves, which in turn represents the peak of the respective daily curves. A brief discussion is also presented on the relationship between the fitting parameters obtained from the model and the mitigation measures adopted in each of the municipalities considered. Conclusions: The generalized Richards model proved to be very effective in describing epidemic curves of Covid-19 and estimating important epidemiological parameters, such as the time of the peak of the curve for daily cases and deaths, thus allowing a practical and efficient monitoring of the epidemic evolution.

Introdução: A pandemia da Covid-19 é uma das maiores crises de saúde pública que o mundo já enfrentou. Nesse contexto, é importante ter modelos eficazes para descrever os diferentes estágios da evolução da epidemia, a fim de orientar as autoridades competen- tes na adoção de políticas públicas para o enfrentamento da mesma. Objetivo: Apresentar uma análise de curvas epidêmicas com base em modelos fenomenológicos de crescimento, tomando como exemplo as curvas acumuladas de casos confirmados de infecção pelo novo coronavírus (Sars-Cov-2) e de óbitos atribuídos à doença (Covid-19) causada pelo vírus, para as cidades do Recife e Teresina. Métodos: Foram utilizados o modelo generalizado de Richards e o modelo de crescimento generalizado para fazer o ajuste numérico das respectivas curvas empíricas. Resultados: Verificou-se que os modelos utilizados descrevem muito bem as curvas empíricas em que foram testados. Em particular, o modelo generalizado de Richards é capaz de identificar com razoável confiabilidade o surgimento do ponto de infle- xão nas curvas acumuladas, o qual corresponde ao ponto de máximo das respectivas curvas diárias. Apresenta-se ainda uma breve discussão sobre a relação entre os parâmetros obtidos no ajuste do modelo e as medidas de mitigação adotadas para retardar a propagação da Covid-19 em cada um dos municípios considerados. Conclusões: O modelo generalizado de Richards mostrou-se bastante eficaz para descrever curvas epidêmicas da Covid-19 e es- timar parâmetros epidemiológicos importantes, como o pico das curvas de casos e óbitos diários, permitindo assim realizar de modo prático e eficiente o monitoramento da evolução da epidemia.

The collection time could be an important target for optimizing technological processes in obtaining essential oils of interest to agribusiness. The objective of this study was to distinguish the time for the collecting of Achillea millefolium L. leaves, which provides the highest yield and quality of the essential oil. Also, identify the type of polyethylene packaging and leaf storage period during the one-year period that would maintain the essential oil characteristics. Gas chromatography-mass spectrometry and chemometric studies were performed into two steps trial to detect changes in chemical profile induced by different conditions. First, an analysis of the leaf collection time was performed using chromatographic data from six different gathering times throughout the day. After determining the best time to collect from the leaves, the essential oil was extracted in five storage periods over a year. The highest oil content was observed in leaves harvested between 11 and 15 h, with a maximum of 39 min after 13 h. Therefore, it is recommended to perform extraction in the early afternoon. There was no significant statistical differentiation related to polyethylene packages. In addition, it is recommended that the essential oil can be stored without significant changes for up to six months.