Design and implementation of an IoT gateway to create smart environments

The paper presents a proposal of a practical implementation for an IoT gateway dedicated to real-time monitoring and remote control of a swimming pool. Based on a Raspberry Pi, the gateway allows bidirectional communication and data exchange between the user and the sensor network implemented on the environment using an Arduino.info:eu-repo/semantics/publishedVersio

Academic Achievement in Physics-Chemistry: The Predictive Effect of Attitudes and Reasoning Abilities

Science education plays a critical role as political priority due to its fundamental importance in engaging students to pursue technological careers considered essential in modern societies, in order to face scientific development challenges. High-level achievement on science education and positive attitudes toward science constitutes a crucial challenge for formal education. Several studies indicate close relationships between students’ attitudes, cognitive abilities, and academic achievement. The main purpose of this study is to analyze the impact of student’s attitudes toward the school discipline of Physics and Chemistry and their reasoning abilities on academic achievement on that school subject, among Portuguese 9th grade students using the data collected during the Project Academic Performance and Development: a longitudinal study on the effects of school transitions in Portuguese students (PTDC/CPE-CED/104884/2008). The participants were 470 students (267 girls – 56.8% and 203 boys – 43.2%), aged 14–16 years old (m D 14.3 0.58). The attitude data were collected using the Attitude toward Physics-Chemistry Questionnaire (ATPCQ) and, the Reasoning Test Battery (RTB) was used to assess the students reasoning abilities. Achievement was measured using the students’ quarterly (9-week) grades in the physics and chemistry subject. The relationships between the attitude dimensions toward Physics-chemistry and the reasoning dimensions and achievement in each of the three school terms were assessed by multiple regression stepwise analyses and standardized regression coefficients (b), calculated with IBM SPSS Statistics 21 software. Both variables studied proved to be significant predictor variables of school achievement. The models obtained from the use of both variables were always stronger accounting for higher proportions of student’s grade variations. The results show that ATPCQ and RTB had a significantly positive relationship with student’s achievement in Physics-chemistry, indicating that both attitudinal and cognitive variables should be taken into account on science education as well as in educative intervention

Métodos de análise quantitativa inorgânica em caldo de cana de açúcar; vinhaça e melaço: I. determinação de cálcio, magnésio, potássio, enxofre e fósforo em um mesmo extrato

This paper reports a study about the determination of inorganic constituents (calcium, magnesium, potassium, sulfur (as sulfate) and phosphurus (as phosphate) in sugar cane juice, vinasse and molasses. Two techniques for organic matter oxidation were studied: wet and dry digestion. The data obtained showed that for these determinations any of these procedures can be employed, excepting the sulfur determination in molasses which must be made be wet digestion. The proposed techniques employ analytical methods acessible to most laboratories and permit fast and accurate determination of the five inorganic constituents.Neste trabalho é apresentada uma marcha analítica simples, rápida e acessível à maioria dos nossos laboratórios, visando a determinação de constituintes inorgânicos do caldo de cana de açúcar, vinhaça e melaço. Foram estudadas duas técnicas para a digestão do material (via seca e via úmida) e a seguir, nos extratos obtidos determinados cálcio, magnésio, potássio, enxofre e fósforo. Os dados obtidos mostraram que para a análise dos citados constituintes, nos mencionados materiais, pode ser empregado, indiferentemente, o ataque por via seca ou úmida, excetuando-se a determinação de enxofre em melaço que deve ser efetuada por via úmida. As técnicas de análise preconizadas apresentaram uma adequada precisão, conforme demonstram os resultados obtidos neste trabalho

A disponibilidade do fósforo de oiversos fosfatos estudada por meio do método de Neubauer"

In order to study the phosphorus availability from various phosphates fertilizers an experiment was performed according to the biological seedling method of Neubauer. The physico-chemical properties of the soil "terra roxa-misturada", a red soil derived from basaltic rocks are given in the Portuguese text. Rice (Oryza sativa, L.) instead of rye (Secale cereale, L.) was used. Five replications of each of the following treatments were made: 1 - check, with 350 g of sand 2 - 350 g of sand plus 100 g of soil 3 - 350 g of sand and plus 100 g of soil plus 40 mg of P2O5, from superphosphate. 4 - 350 g of sand plus 100 g of soil plus 40 mg of P2O5. from Olinda (Brazil) phosphorite. 5 - 350 g of sand plus 100 g of soil plus 40 mg of P2O5 from Florida (U. S. A.) phosphorite. 6 - 350 g os sand plus 100 g of soil plus 40 mg of P2O5 from Hyperphosphate, a commertial name of a North African (Gafsa) phosphorite. 7 - 350 g of sand plus 100 g of soil plus 40 mg of P2O5 from Araxá (Brazil) apatite. After 18 days of growth, the roots and tops of rice seedlings were harvested and analysed for phosphorus, and the results are summarized in table 1. Table 1 - Milligrams of P2O5 determined in rice seedlings. Treatments Mean of 5 replications mg of P2O5 1 ..................... 24.196 2 ..................... 23.850 3 ..................... 30.724 4 ..................... 27.620 5 ..................... 27.480 6..................... 30.210 7 ..................... 26.032 The least significant difference at the 5% level by Tukey's procedure for comparisons among the treatments means is 1.365 mg of P(2)0. It is interesting to observe that rice plants did not take any phosphorus from the soil according to he data of the treatments n.° 1 and n.° 2. This can be explained by the high phosphorus fixing capacity of the soil "terra roxa misturada"

Aplicação do método espectrofotométrico da 2,2'-dipiridil cetoxima na determinação do cobalto em plantas

As a conclusion of the studies on the spectrophotometric method using 2,2,-dipyridyl ketoxime, it is suggested a technique for the cobalt determination in plants. The method, as it is proposed, presents both precision and accuracy sonsidered satisfactory, and the least relative error of the concentration is obtained in the range from 0,9 to 9,0 or 1,0 to 10,0 microgrames of cobalt in 3ml of solvent. It follows Beer's law and the molar absorptivity of the compound is 17.685. The results of cobalt determination in several vegetables are presented.Os resultados obtidos nos estudos da parte experimental do método da 2,2'-dipiridil cetoxima, permitiriam o estabelecimento de uma técnica para a determinação do cobalto em plantas. A aplicação do método foi precedida de uma avaliação de sua amplitude, exatidão e precisão. Verificou-se que nos intervalos de 0,9 a 9,0 ou de 1,0 a 10,0 microgramas de cobalto/3 ml do solvente, foram obtidos os menores erros relativos da concentração. Dentro dos limites estudados, o método segue a lei de Beer. A precisão da técnica proposta, avaliada através de ensaios de recuperação, foi considerada satisfatória

Determinação colorimétrica do silício em vegetais

O presente trabalho relata os estudos do método colorimétrico de determinação do silício, baseado na reação do citado elemento com o anion molibdato e posterior redução do sílico-molibdato formado com solução de ácido ascórbico contendo ferro divalente. Os estudos efetuados permitiram estabelecer uma técnica rápida para determinação do silício em material vegetal, mediante ataque das cinzas provenientes do material vegetal, com ácidos clorídrico, fluorídrico e excesso de ácido bórico, e posterior aplicação do método colorimétrico. Foram realizadas determinações de silício em materiais vegetais de diferentes origens, obtendo-se satisfatória precisão e os resultados concordaram razoavelmente com aqueles fornecidos pelo método gravimétrico tradicional.The present work reports a study about the determination of silicon in plant materials, using the method based in the formation of heteropoly blue complex (molybdenum blue method) A preliminary study about the influence of several factors that may affect the method was performed. It was studied the absorption of the molybdenum blue, the influence of oxalic acid, effect of time and pH on the formation of molybdsilicic acid and its reduction, the influence of the use of hydrofluoric acid for solubilization of silicates and the reducing solutions. Based in this preliminary studies, it was proposed a technique for the determination of silicon in plant materials employing the colorimetric method. In the recommended procedures the plant materials ash is treated with a mineral acid (HC1), hydrofluoric acid and excess of boric acid. The reduction of molybdisilicic acid is made using an acid ascorbic solution containing divalent iron. In all procedure it is not necessary the use of platinum or nickel ware. In order to compare the colorimetric (based in the proposed technique) and gravimetric methods, five replications of differents plant materials were analysed by both methods. The data obtained allowed to conclude that the technique proposed is good and the accuracy is satisfactory

Determinação da capacidade de troca de cátions, do solo por fotometria de chama

O presente trabalho relata os dados obtidos sobre a determinação da capacidade de troca de cátions do solo, através da determinação do cálcio por fotometria de chama. A amostra de solo (2g) foi prèviamente saturada com íons cálcio, o excesso do reagente foi lavado e o cálcio deslocado do solo, mediante extração com solução normal de acetato de amônio pH 7. A determinação do cálcio, contido no extrato, foi feita mediante o emprêgo do fotômetro de chama Coleman modêlo 21. Os dados obtidos, demonstraram que a técnica adotada, além de sua simplicidade e rapidez, fornece resultados cuja precisão é satisfatória.This paper describes a method for determining cation exchange capacity of soils (C.E.C.).Two grams sample of 9 different soils were placed in a percolation tube with diammeter of 15 mm and lenght of 200 mm. Twenty mililiters of normal calcium acetate solution pH = 7,0 were percolated through the soil. Excess of calcium acetate was washed with ethyl alcohol 80% (80 parts of alcohol plus 20 parts of water, in volume) by suction. Adsorbed calcium was extratecd with 50 ml of normal ammonium acetate solution (pH - 7,0) by suction. Calcium extratecd by ammonium acetate solution was determined by photometry.The method described is very rapid and afford a good precision, according to table 1

Método do EDTA na determinação do cálcio e magnésio "trocável" do solo

This paper describes the determination of exchangeable calcium and magnesium in soil by using ethylenediamine tetracetic acid, after the separation of the principals interferents (iron, aluminum, manganese and phosphate) by using both ammonium hidroxide and ammonium sulfide in only one operation. In order to compare the chelometric and the permanganometric methods for determining exchangeable calcium, five replications of nine soils were analysed by both methods. The accuracy of the determination of exchangeable magnesium in soil was evalueted by means of the recovered magnesium, when the proposed method was applied. The data obtained in both studies allowed to conclude that the technique proposed is good and the accuracy is satisfactory

Adsorção de sulfato pelo solo

The adsorption of sulfate by soil samples was studied and the data obtained showed that amount of SO4(2-) adsorbed increased with the equilibrium aqueous phase sulfate concentration at constant soil pH and decreased with soil pH at constante sulfate concentration of the equilibrium solution. The linear form of the Freundlich adsorption equation expressed the relationship between log x/m and between log C and soil pH.Avaliou-se a capacidade de retenção ou adsorção do ânsion sulfato por várias amostras de solos, mediante a agitação de dois gramas de material com 5 ml de soluções padrões contendo quantidades crescentes de sulfato. Após um repouso durante 16 horas, procedeu-se à determinação do teor de sulfato da solução de equilíbrio. Calculou-se a quantidade de sulfato adsorvida por diferença entre a originalmente existente e a determinada na solução de equilíbrio após a agitação da suspensão do solo e repouso. O material estudado constituiu-se de amostras de solos procedentes de vários horizontes de diversas séries do Município de Piracicaba, tratadas com carbonato de cálcio a fim de se obter uma variação relativamente ampla do pH. Os dados obtidos evidenciaram que a quantidade de sulfato adsorvido pelas amostras de solos estudadas aumenta com a concentração de sulfato da solução de equilíbrio e diminui à medida que se eleva o pH. A equação de Freundlich, na sua forma linear, traduziu de um modo adequado a dependência da quantidade de sulfato adsorvida pelo so lo (log x/m) da concentração de sulfato da solução de equilíbrio (log c) e do pH do solo

Dengue in pregnancy and maternal mortality: a cohort analysis using routine data.

Dengue is a mosquito-borne disease with major public health importance due to its growing incidence and geographical spread. There is a lack of knowledge on its contribution to maternal death. We conducted a population-based cohort study to investigate the association between symptomatic dengue during pregnancy and deaths in Brazil from 2007 to 2012. We did this by linking routine records of confirmed dengue cases to records of deaths of women who had a live birth. Using the Firth method, we estimated odds ratios for maternal deaths associated with dengue during pregnancy. Dengue increased the risk of maternal death by 3 times (95%CI,1.5-5.8) and dengue haemorrhagic fever increased the risk of maternal death by 450 times (95%CI,186.9-1088.4) when compared to mortality of pregnant women without dengue. The increase in risk occurred mostly during acute dengue 71.5 (95%CI,32.8-155.8), compared with no dengue cases. This study showed an increased risk of adverse outcomes in pregnant women with dengue. Therefore in areas where dengue is circulating, the health of pregnant women should be not only a public health priority, but health professionals attending pregnant women with dengue should more closely observe these patients to be able to intervene in a timely way and avoid deaths