O uso de modelos no ensino de química: uma investigação acerca dos saberes construídos durante a formação inicial de professores de Química da UFRN

In the past twenty years, there has been a significant increase of researches about teacher s professionalization. In that context, the investigations concerning teacher s knowledge represent an important contribution, as they aim to identify and to rescue the base of knowledge that sustains the teacher s profession. In particular, the reflections and propositions of Lee Shulman have been constitute a fundamental subsidy to the teacher s professionalization in the sense of harnessing the pedagogic knowledge to the content s knowledge, establishing the pedagogic knowledge of the content that characterizes and differentiates the teacher and the bachelor in a certain field of knowledge. Among the indispensable knowledge for the Chemistry teacher's professional practice, in this research we have pointed out the pertinence of the knowledge on the use of models in Chemistry classes in the middle and high school. Those knowledges regard the comprehension of students concerning the understanding and models elaborated in science and the models implemented in the Chemistry teaching, as well as the abilities to plan didactic situations that use models. In this research, we aimed to identify the contributions and barriers during the Chemistry teacher education, in UFRN, in relation to the construction of knowledge that subsidize training teachers in the elaboration of teaching activities that involve the use of models. The investigation was accomplished in UFRN, in the Course of Degree in Chemistry, along with 13 student teachers that studied the subject Practice of Chemistry Teaching. For this research, the following instruments were used: questionnaires with open and closed questions, elaboration of a plan of activities for the Chemistry teaching and an interview to answer the established study s questions. The data was analyzed in an established criteria, classified and tabled. The results showed that the student teachers representations regarding scientific knowledge contemplated, among other topics, the idea of a method for his/her construction. In some cases, the models role was emphasized in that construction, as well as the social dimension in the validation of that knowledge. The scientific models were highlighted by most of the student teachers, as a representation method to explain, understand and interpret the chemical phenomena. On the other hand, the didactic models stood out, in most of cases, as a method of aiding the Chemistry students of the Basic Education to understand the scientific models. The representations regarding those categories contemplated important aspects, although in a superficial way, reflecting the limitations of reflections during the formative process. In the elaboration of teaching activities that use models, difficulties were evidenced, in the process of plan construction, relative to the didactic structure and to the proposition of activities that contemplated models, although the student teachers have mobilized different elements regarding the pedagogic knowledge of the content. Such verifications evidence the urge for the teacher development programs to promote changes in the teacher education in order to propitiate, during this process, reflections, discussions and propositions of activities regarding categories highlighted in this research, contributing to the construction of initial elements regarding the pedagogic knowledge of the content that will be developed throughout teaching, therefore corroborating to the teacher s professionalization

O lugar pedagógico da educação física na educação infantil: saberes (re)construídos na formação continuada do PAIDÉIA/UFRN

The present study aimed to investigate the overview of teachers in continuing education program who work in kindergarten, about the continuing education developed by the Paideia/UFRN through the Course of Specialization in Art Teaching and Physical Education in Childhood, having as key focus, the knowing / doing related to physical education in Childhood. From this general goal, it was elected some specific objectives as: to know the interests and expectations that motivated the teachers to participate of that referred training; the evaluation by teachers on regard of the continuing education proposed: boosters factors for possible changes in teaching activities regarding the practice of teaching physical education in kindergarten. The methodology took the principles and techniques of qualitative research strategy and the characteristics of descriptive and interpretive strategy. The locus of this research was the Course of Specialization in Art Education and Physical Education in childhood, having as the citizens of this research twenty three teachers taking that specialization course. For building and systematization of the data, we used the following tools and procedures: a questionnaire, a semi structured interview and documents analysis. The data was constructed based on the technique of content analysis, focusing the reflections and speech of the teachers about the creation of new meanings and senses for the knowing / doing in Physical Education. It was found, among other results, the need and quest for improvement of teacher education, in order to improve educational practice. It was also evident that the situations of dialogues (interactions with peers, with their professors and other professionals in the related area or not) were mentioned by most teachers in the course as a relevant moment of redefinition of knowledge. In relation to Physical Education, it was found that participation in the course of specialization provided the recognition of teaching practice of physical education as part of the curriculum and the importance of inclusion of its specificities in their educational planning. From these elaborations, we come to the conclusion that knowing the perspectives of the teachers about continuing education can contribute to the theoretical and methodological discussions in teachers education and the creation of new actions - projects and programs of continuing education constructing increasingly ways towards a successful teacher formation, able to provide new forms of acting in the educational context

Avaliação do processo oxidativo avançado por permanganato de potássio no tratamento de solos contaminados com idrocarbonetos poliaromáticos

The soil contamination with petroleum is one of the major concern of industries operating in the field and also of environmental agencies. The petroleum consists mainly of alkanes and aromatic hydrocarbons. The most common examples of hydrocarbons polyaromatic are: naphthalene, anthracene, phenanthrene, benzopyrene and their various isomers. These substances cause adverse effects on human and the environment. Thus, the main objective of this work is to study the advanced oxidation process using the oxidant potassium permanganate (KMnO4) for remediation of soils contaminated with two polyaromatic hydrocarbons (PAHs): anthracene and phenanthrene. This study was conducted at bench scale, where the first stage was at batch experiment, using the variables: the time and oxidant dosage in the soil. The second stage was the remediation conducted in continous by a fix column, to this stage, the only variable was remediation time. The concentration of oxidant in this stage was based on the best result obtained in the tests at batch, 2,464 mg / L. The results of degradation these contaminants were satisfactory, at the following dosages and time: (a) 5g of oxidant per kg soil for 48 hours, it was obtained residual contaminants 28 mg phenanthrene and 1.25 mg anthracene per kg of soil and (b) for 7g of oxidant per kg soil in 48 hours remaining 24 mg phenanthrene and anthracene 0.77 mg per kg soil, and therefore below the intervention limit residential and industrial proposed by the State Company of Environmental Sao Paulo (CETESB)

Remediação de solos contaminados com óleo diesel utilizando um sistema de lavagem com microemulsão

The underground reservoirs of fuel retailing system represent an environmental threat, because once in bad conservation, these tanks allow fuel leakage and infiltration. For soil contaminated with fuel, such as diesel oil, the present study introduces the microemulsion systems used by the method of washing. In tests carried out in column with a sample of sandy soil artificially contaminated and previously characterized as to its void level to porosity, to permeability which is an important parameter concerning the study of the method of washing. While microemulsions were characterized for their viscosity and wettability, a variation of active matter was also done departing from the original formulation. The hydraulic diffusivity of the microemulsion was studied so as the injection of such fluid in a soil with sandy characteristics. The results of the extractions revealed the excellent performance of these systems which get to remove around 95% of diesel fuel. This proves the efficiency of the microemulsion in the process of removal of diesel fuel from the soil with the advantage of being a system easily obtainable and less aggressive to the environment when compared to organic solvents.

Estudos in silico da proteína AlkB e prospecção de bactérias alcanotróficas em solos da bacia petrolífera potiguar

Some microorganisms from virgin ecosystems are able to use petroleum it as source of carbon and energy. The knowledge of microbial biodiversity can help to reveal new metabolic systems for utilization alkanes with biotechnological importance. The aim of this study is: i) Accomplish an in silico study of the AlkB protein aimed to understand the probable mechanism involved on selectivity of alkanes in Gram positive and Gram negative bactéria. ii) prospect and analyze the response of the microbial alkanotrophics communities in soil and mangrove sediments of BPP RN and soil of Atlantic forest in the Horto Dois Irmãos Reserve area/PE using the molecular biomarker, gene alkB; with the PCR and PCR-DGGE approach

Os significados do tabagismo construídos na dinâmica social

The present study has the purpose of catching the significances of smoking in the social dinamics based on the Theory of Social Representations. It was developed among adults with ages from 20 to 59 years, low social and economic conditions, at Natal RN, Brazil. The Free-words Association Test was applied as the instrument of data collection and a semi-structured interview with the smokers and non-smokers, besides a structured interview with smokers, non-smokers and ex-smokers. All data was analyzed by the descriptive statistics using the Analysis of Content Technique of the thematic kind and by the softwares ALCESTE and EVOC 2000. Elaborations about smoking were marked by social, cultural and historical dimension, however they showed sensibility to changes and revealed positive and negative aspects of the habit. The analysis of the semi-structured interviews showed the following categories and under-categories respectively: Initiation of the habit (Friends and Family and Appreciation and Beauty); Psychosocial Implications of smoking (Personal relationship, Work and Financial); Behavior when facing smoking (Positive, Negative and Neutral); Smoking Effects (Smokers´ health and the other people health); Description about oral diseases ( Bad breath, Oral cancer and Dental problems); Smoking treatment (Physician and psychological, Supernatural and Difficulties). ALCESTE analysis presented 4 classes: Ambivalence between pleasure and get ill, Smoking as a trouble and danger to society, Social discrimination of smokers and Mouth as a place of reaffirmation of the discrimination. Those helped us to understand the psychosocial repercussion of the habit. On the social representation structure we identified as a probable central nucleus of the smoker group the categories Pleasure and Bad to the health and as peripheral elements Alcoholic Drink, Financial damage and Nervousness. For the non-smoker group the category Bad to the health comes first and Stop Smoking comes as a peripheral element. Finally, we hope that the knowledge of these representations can contribute to plan and/or to rethink over the professional practices and public policies related to smoking. Besides that, for an amplified comprehension of the study object the discussions over the identified representations should be deepen and amplified to other population and social groups

Remediação de solos contaminados com diesel por lavagem com solução de tensoativos

Combating pollution of soils is a challenge that has concerned researchers from different areas and motivated the search for technologies that aim the recovery of degraded soils. Literature shows numerous processes that have been proposed with the intent of remediating soils contaminated by oils and other by-products of the oil industry, considering that the processes available have, generally, high operating costs, this work proposes a costeffective alternative to the treatment of Diesel-contaminated soils. The washing solutions were prepared using water as aqueous phase, the saponified coconut oil (OCS) as surfactant and n-butanol as co-surfactant. In this study, the soil was characterized by physical and chemical analyses. The study of diesel desorption from the soil was held in bath, using hexane and washing solutions, which had 10 and 20 wt.% active matter (AM - co-surfactant/surfactants) respectively. The study of the influence of active matter concentration and temperature in bath agitated used an experimental planning. The experiment also developed a system of percolation in bed to wash the soil and studied the influence of the concentration of active substance and volume of washing solution using an experimental planning. The optimal times to achieve hexane extraction were 30 and 180 min, while the best results using a 10% AM was 60 min and using a 20% AM was 120 min. The results of the experimental planning on bath showed that the maximum diesel removal was obtained when at a 20 wt.% of AM and under 50 °C, removing 99.92% of the oil. As for experiments in the system of percolation soil bed, the maximum diesel removal was high when the volume of the washing solution was of 5 L and the concentration of 20% AM. This experiment concluded that the concentration of AM and the temperature were vital to bath experiments for diesel removal, while in the system of percolation soil bed only concentration of AM influenced the soil remediation

Detecção de metamidofós em solos por métodos ecotoxicológico e cromatografia líquida acoplada à espectrometria de massas sequencial (LC-MS/MS)

Soil contamination by pesticides is an environmental problem that needs to be monitored and avoided. However, the lack of fast, accurate and low cost analytical methods for discovering residual pesticide in complex matrices, such as soil, is a problem still unresolved. This problem needs to be solved before we are able to assess the quality of environmental samples. The intensive use of pesticides has increased since the 60s, because the dependence of their use, causing biological imbalances and promoting resistance and recurrence of high populations of pests and pathogens (upwelling). This has contributed to the appearance of new pests that were previously under natural control. To develop analytical methods that are able to quantify residues pesticide in complex environment. It is still a challenge for many laboratories. The integration of two analytical methods one ecotoxicological and another chemical demonstrates the potential for environmental analysis of methamidophos. The aim of this study was to evaluate an ecotoxicological method as "screening" analytical methamidophos in the soil and perform analytical confirmation in the samples of the concentration of the analyte by chemical method LC-MS/MS In this work we tested two soils: a clayey and sandy, both in contact with the kinetic methamidophos model followed pseudo-second order. The clay soil showed higher absorption of methamidophos and followed the Freundlich model, while the sandy, the Langmuir model. The chemical method was validated LC-MS/MS satisfactory, showing all parameters of linearity, range, precision, accuracy, and sensitivity adequate. In chronic ecotoxicological tests with C. dubia, the NOEC was 4.93 and 3.24 for ng L-1 of methamidophos to elutriate assays of sandy and clay soils, respectively. The method for ecotoxicological levels was more sensitive than LC-MS/MS detection of methamidophos, loamy and sandy soils. However, decreasing the concentration of the standard for analytical methamidophos and adjusting for the validation conditions chemical acquires a limit of quantification (LOQ) in ng L-1, consistent with the provisions of ecotoxicological test. The methods described should be used as an analytical tool for methamidophos in soil, and the ecotoxicological analysis can be used as a "screening" and LC-MS/MS as confirmatory analysis of the analyte molecule, confirming the objectives of this work