Contextualização na Matemática: percursos e percalços

O presente trabalho busca verificar as reais possibilidades da Contextualização no ensino de Matemática, partindo dos Parâmetros Curriculares Nacionais (PCN) e inserindo-se na vida escolar por meio das convicções dos educadores e livros didáticos. Os PCN marcaram o posicionamento do Ministério da Educação contrário à metodologia do ensino tradicional, que no ensino de Matemática representou a vitória das correntes pedagógicas constituídas sobre as críticas ao ensino da Matemática Moderna. O termo utilizado para unificar as diferentes correntes foi a Contextualização. Assim, o ensino contextualizado seria baseado no cotidiano e nos conhecimentos prévios dos estudantes e por meio da resolução de problemas abordaria os temas transversais, a história ou aplicações da Matemática. Mas, entrevistando professores da rede particular de ensino de Maceió e analisando os livros didáticos utilizados por estes observa-se que dificilmente este recurso preconizado pelos documentos oficiais conseguirá ser implantado

Processes for alcohol-free beer production : a review

Since the invention of beer by the Sumerian people in 5000 BC, alcohol was the main reason of the interest of consumers on beer. Only in the beginning of the 20th century alcohol-free beer was demanded and since then technology has advanced dramatically in the production of those beverages. The aim on alcohol-free beer production is to have products that taste similarly to their alcoholic equivalents, the sole absence of alcohol and low concentrations of esters and higher alcohols and the higher concentration of aldehydes create a “worty” organoleptic impression of those products. Alcohol-free beers can be obtained by the restriction of alcohol formation during fermentation, the use of special yeast strains that consume or don’t produce alcohol, the thermal removal of alcohol and by the removal of alcohol trough membrane processes. Membrane separated alcohol-free beers preserve more of the natural constituents of beer aroma and those products usually taste better than those obtained through other processes. Pervaporation techniques show a broad spectrum of use and can even be combined with other processes and perform the removal of undesired products or separation and recuperation of aromatic substances

Scaling-up climate services with users in Latin America

Latin America farmers are highly vulnerable to climate variability, with crop losses observed throughout the region on a virtually annual basis. For instance, as indicated by the United Nations’ Food and Agriculture Organization (FAO) and World Food Program (WFP), the 2014–2017 drought conditions in Central America affected over 3.5 million people in Guatemala, Honduras and El Salvador. At the same time, local stakeholders and farmers generally have limited access to existing climate and forecast information, do not have sufficient capacities to understand the climate information and/or mechanisms to relate this information to the impact that climate variations can generate at a local level. This precludes the translation of information into actionable knowledge, and therefore into action. In this study, we describe a process through which scientists and strategic partners have co-developed, tested and scaled out an approach to assess, co-produce, translate and transfer climate information to enable agricultural decision making –the Local Technical Agroclimatic Committees (LTAC). LTACs allow open and clear dialogues about climate variations at multiple timescales, how these can affect crops, and the design of measures to reduce crop loss, particularly providing agronomic recommendations to farmers. We systematically describe the process of evidence generation, creation, partner engagement, scaling up, and monitoring of the approach throughout Latin America. Currently, 35 LTACs exist in 9 Latin American countries, engaging more than 250 public and private institutions, increasing the resilience and food security of an estimated 330,000 farmers, and potentially transforming how Latin American farmers manage climate risk. The study illustrates changes in institutional and farmers' capacities to co-produce, translate and use climate information and explores how better climate and crop prediction models can effectively underpin this process. We show how strategic alliances with farmer organizations, national public, and private and regional climate outlook forums help deliver improved and accurate climate information to users. Finally, we document how LTACs and their integration with other local-scale processes have led to changes in farmers’ management practices to take better advantage of good climatic conditions or avoid losses

Analysis of solutions of differential equations of vibratory systems with varied external forces

Several Engineering problems can be modeled from differential equations, analytical and numerical methods can be employed to determine the solutions. Among these problems, applied in the area of Mechanics, there are those that involve the analysis of vibratory systems. The present work aims to conduct a study on the solutions of the second order ordinary differential equations that model these vibratory systems, seeking to solve these equations analytically from the application of different external forces. In order to solve analytically each of the equations that describe these systems, the homogeneous equation solution is first determined. Then, depending on the type of external force that acts on the system, the particular solution is obtained using the methods of Indeterminate Coefficients or Parameter Variation. The general solution is then obtained from the linear combination of homogeneous and the particular solutions. The analysis of the solutions shows that the displacements of the masses according to time, depending on the external force applied in the system, present varied behaviors among themselves. Over time, the homogeneous solution, characterized as transient response, becomes negligible, remaining only the particular solution, characterized as the permanent response.

Análise quantitativa da remoção de esmalte dental durante a técnica de microabrasão

Objetivo: Quantificar, por meio de perfilometria, a profundidade de esmalte dental removido durante o emprego de uma técnica de microabrasão utilizando-se ácido clorídrico e abrasão manual com espátula plástica. Método: Trinta e seis espécimes obtidos de terceiros molares humanos foram polidos, para obtenção de superfícies planas, e divididos em 3 grupos (n = 12) de acordo com os diferentes tratamentos recebidos: tratamento placebo com água deionizada, como controle negativo (CG); microabrasão com ácido clorídrico a 6.6%, OpalustreTM (G1); e ácido clorídrico a 6%, Whiteness RMTM (G2). A microabrasão foi realizada, de forma padronizada, submetendo os espécimes a 4 ciclos de 10 segundos cada e abrasão manual utilizando-se uma espátula plástica com carga de 200 g. A perda da superfície de esmalte foi medida após cada um dos ciclos de tratamento por meio de perfilômetro de contato. Resultados: Após os primeiros 10 segundos de abrasão, já foi encontrada perda de esmalte em ambos os grupos tratados (G1 e G2). Nos grupos G1 e G2, a cada ciclo de 10 segundos, foi observado um aumento significativo na perda de esmalte (p ≤ 0.05). Após 4 abrasões de 10 segundos cada, as médias de perda de esmalte nos grupos tratados foram 46.04 μm (G1) e 54.65 μm (G2). Foi encontrada uma diferença significativa entre G1 e G2 com relação à perda de esmalte após 30 e 40 segundos de microabrasão. Relevância: Os resultados deste estudo fornecem referências para a realização do procedimento de microabrasão em esmalte dental com segurança, utilizando-se ácido clorídrico e abrasão manual com espátula plástica.Objective: To quantify, by means of profi lometry, the removal of dental enamel during the use of a microabrasion technique involving the use of hydrochloric acid and manual abrasion with a plastic spatula. Method: Thirty six specimens obtained from human third molars were polished to obtain fl at surfaces and divided into 3 groups (n = 12) according to the different treatments received: A placebo treatment with deionized water as a negative control (CG); microabrasion with 6.6% hydrochloric acid, OpalustreTM (G1); and microabrasion with 6% hydrochloric acid, Whiteness RMTM (G2). The microabrasion was performed in a standardized manner by submitting the specimens to 4 cycles of 10 seconds each and manual abrasion using a plastic spatula (200 g load). The loss of enamel surface was measured after each cycle of treatment by contact profi lometry. Results: Enamel loss was already observed after the fi rst 10 seconds of abrasion with hydrochloric acid in both treated groups (G1 and G2). After 4 abrasions of 10 seconds each, the average fi nal enamel losses in the treated groups were 46.04 μm (G1) and 54.65 μm (G2). In the G1 and G2 groups, a signifi cant increase in enamel wear was detected in each cycle in comparison to the control group (p ≤ 0.05). A signifi cant difference in enamel loss between G1 and G2 was found after 30 and 40 seconds of microabrasion. Relevance: The results of this study provide objective data for safely performing the microabrasion technique on dental enamel using hydrochloric acid and manual abrasion using a plastic spatula

Maternal Fibroblast Growth Factor 21 Levels Decrease during Early Pregnancy in Normotensive Pregnant Women but Are Higher in Preeclamptic Women—A Longitudinal Study

Fibroblast growth factor 21 (FGF-21) is an endocrine factor involved in glucose and lipid metabolism that exerts pleiotropic effects. The aim of this study was to investigate the serum FGF-21 profile in healthy and mild preeclamptic pregnant women at each trimester of pregnancy; (2) Methods: Serum FGF-21 levels were determined by ELISA in a nested case-control study within a longitudinal cohort study that included healthy (n = 54) and mild preeclamptic (n = 20) pregnant women, women at three months after delivery (n = 20) and eumenorrheic women during the menstrual cycle (n = 20); (3) Results: FGF-21 levels were significantly lower in the mid-luteal phase compared to the early follicular phase of the menstrual cycle in eumenorrheic women (p < 0.01). Maternal levels of FGF-21 were significantly lower in the first and second trimesters and peaked during the third trimester in healthy pregnant women (p < 0.01). Serum levels of FGF-21 in healthy pregnant were significantly lower in the first and second trimester of pregnancy compared with the follicular phase of the menstrual cycle and postpartum (p < 0.01). Serum FGF-21 levels were significantly higher in preeclamptic compared to healthy pregnant women during pregnancy (p < 0.01); (4) Conclusions: These results suggest that a peak of FGF-21 towards the end of pregnancy in healthy pregnancy and higher levels in preeclamptic women might play a critical role that contributes to protecting against the negatives effects of high concentrations of non-esterified fatty acids (NEFA) and hypertensive disorder. Furthermore, FGF-21 might play an important role in reproductive function in healthy eumenorrheic women during the menstrual cycle

Effects of high-intensity interval and moderate-intensity continuous exercise on inflammatory, leptin, IgA, and lipid peroxidation responses in obese males

Purpose: To compare the effects of a single high-intensity interval exercise session (HIIE) with amoderate-intensity continuous exercise session (MICE) on the inflammatory profile, IgA levels, and lipid peroxidation in sedentary obese males. Methods: Ten sedentary obese men (age 28.5 ± 2.7 years; BMI 35.9 ± 4.9 kg/m2; body fat 40.6 ± 2.0%) performed three experimental sessions, on separate days with 1 week wash-out period between interventions, according to a randomized order: (1) HIIE: 10 × 60 s at 90% of the HRmax alternated by 60 s of active recovery; (2) MICE: 20min at 70% of the HRmax; (3) Rest—control. Blood and saliva samples were collected before, immediately after and 60min after the end of each session in order to analyse serum levels of cytokines, IgA, and lipoperoxidation markers. Results: Leptin levels decreased immediately after HIIE (P = 0.033) and was different from the MICE (P = 0.025). IFN-g levels were reduced immediately after (P = 0.032) and 60min after HIIE (P = 0.003) compared to baseline, and it also increased IL-4 levels immediately after exercise (P = 0.007) compared to resting values. MICE promoted an increase in IFN-g levels immediately after exercise (P = 0.025) and 60min after exercise (P = 0.004) in relation to baseline. Both exercise conditions increased IL-6 levels up to 60min after exercise (P < 0.05). The IFN-g/IL-4 ratio decreased immediately after (P = 0.002) and 60min after HIIE (P = 0.005) in relation to pre-exercise. No changes were found for IgA-S and TBARS for any of the conditions. Conclusion: A single HIIE session is able to decrease IFN-g/IL-4 ratio, indicating an anti-inflammatory response, without alterations in the function of the mucosal immune systemand lipoperoxidation. On the other hand, a brief session ofMICE induced changes in the pattern of cytokines associated with increased cellular immune function

Maternal serum angiopoietin-like 3 levels in healthy and mild preeclamptic pregnant women

Objective: Angiopoietin-like protein 3(ANGPTL3) is an important regulator of lipoprotein metabolism in the fed state by inhibiting the enzyme lipoprotein lipase in oxidative tissues. However, the possible role of ANGPTL3 throughout gestation and its relationship with hormonal and biochemical variables are still unknown. The aim of this study was to determinate serum ANGPTL3 level in healthy non-pregnant women, during healthy and preeclamptic pregnancy and postpartum. Methods: Serum ANGPTL3 was analyzed by enzyme-linked immunosorbent assay (ELISA), in a prospective cohort of healthy pregnant women (n = 52) and women with mild preeclampsia (n = 21), and women at three months postpartum (n = 20) and healthy non-pregnant women (n = 20). The results obtained were correlated with biochemical, hormonal and anthropometric variables and insulin resistance indices. Results: Levels of ANGPTL3 were not different between the follicular and the luteal phases of the cycle in healthy non-pregnant women. There was a significant reduction in serum ANGPTL3 levels from the first to the third trimester in healthy pregnant women compared with healthy non-pregnant and postpartum women (p 0.05) Conclusions: We describe for the first time the profile of ANGPTL3 throughout pregnancy and postpartum as well as and discussed about explore their potential contribution interactions with lipoprotein metabolism throughout pregnancy and postpartum. Thus, low levels of ANGPTL3 during pregnancy might favor lipid uptake in oxidative tissues as the main maternal energy source, while may helping to preserve glucose for use by the fetus and placenta.Fil: Garces, María Fernanda. Universidad Nacional de Colombia; ColombiaFil: Rodriguez Navarro, Haiver Antonio. Universidad Nacional de Colombia; ColombiaFil: Buell Acosta, Julieth Daniela. Universidad Nacional de Colombia; ColombiaFil: Burgos Cardenas, Alvaro Javier. Universidad Nacional de Colombia; ColombiaFil: Franco Vega, Roberto. Universidad Nacional de Colombia; ColombiaFil: Maldonado Acosta, Luis Miguel. Universidad Nacional de Colombia; ColombiaFil: Eslava Schmalbach, Javier. Universidad Nacional de Colombia; ColombiaFil: Parada Baños, Arturo José. Universidad Nacional de Colombia; ColombiaFil: Castro Pinzon, Andres. Universidad Nacional de Colombia; ColombiaFil: Sanchez, Elizabeth. Universidad Nacional de Colombia; ColombiaFil: Angel Muller, Edith. Universidad Nacional de Colombia; ColombiaFil: Lacunza, Ezequiel. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Inmunológicas Básicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Castaño, Justo P.. Universidad de Córdoba; EspañaFil: Dieguez, Carlos. Universidad de Santiago de Compostela; EspañaFil: Nogueiras, Rubén. Universidad de Santiago de Compostela; EspañaFil: Ruiz Parra, Ariel Ivan. Universidad Nacional de Colombia; ColombiaFil: Caminos, Jorge Eduardo. Universidad Nacional de Colombia; Colombi

SOCIO-POLITICAL CONFLICT AND ECONOMIC PERFORMANCE IN BOLIVIA*

ABSTRACT: We examine how socio-political conflict in Bolivia has affected its economic performance since the 1970s. Such conflict includes strikes, demonstrations, road blockades, and conventional rent-seeking. Since conflict has costs, it diverts resources away from production, tends to reduce investment and could therefore reduce economic growth. We first review the characteristics of conflict in Bolivia using a unique data set. We then provide estimates of the direct costs of conflict and examine the relationship with economic performance using hypotheses derived from a simple model. In particular, we make a distinction between economic growth that is due to external factors -like changes in income due to movements in the terms of trade -and economic growth that is due to productive investment. Growth due to external factors tends to be positively related to conflict, whereas growth due to productive investment should be negatively related to conflict. Finally, we discuss how levels of conflict, economic performance, and governance might be related in Bolivia&apos;s recent history. * We would like to thank participants at the conference on Bolivia, held the Kennedy School of Government in November 2006, for their comments, and especially Francisco Rodriguez for his detailed suggestions. For discussions and background information, we are also very grateful t