Determinação não destrutiva do nitrogênio total em plantas por espectroscopia de reflectância difusa no infravermelho próximo

Diffuse reflectance near-infrared (DR-NIR) spectroscopy associated with partial least squares (PLS) multivariate calibration is proposed for a direct, non-destructive, determination of total nitrogen in wheat leaves. The procedure was developed for an Analytical Instrumental Analysis course, carried out at the Institute of Chemistry of the State University of Campinas. The DR-NIR results are in good agreement with those obtained by the Kjeldhal standard procedure, with a relative error of less than ± 3% and the method may be used for teaching purposes as well as for routine analysis.

La Adquisición de competencias básicas en educación primaria: una aproximación interdisciplinar desde la didáctica de la lengua y de las matemáticas

Este artículo trata de la aplicación de las competencias básicas en el currículum de Educación Primaria. El objetivo que persigue es ofrecer algunas estrategias para ayudar a los maestros a integrar las competencias básicas en los métodos de programación y evaluación. Con este fin, y para prever las posibles dificultades en la implementación de las competencias básicas, en la primera parte del artículo se analiza la situación actual a partir de la lectura de diversos documentos legales vigentes. A continuación, en la segunda parte del artículo se aportan algunas herramientas para facilitar esta integración desde las áreas de lengua y de matemáticas. Realizamos esta aproximación desde la didáctica de la lengua y de las matemáticas por su carácter instrumental para la adquisición de otros conocimientos

Conflicto, colaboración y consenso en la enseñanza de las ciencias sociales = Conflict, collaboration and consensus in the teaching of the Social sciences

This article suggests the study of the key concept of conflict as a means of implementing a critical and communicativecurriculum based on the study of relevant social themes. To this end we put forward the principal characteristics of thecritical/communicative curriculum. We offer a didactic proposal about conflict and explain the results of its application intwo Secondary Education classrooms

Enseñar a convivir, enseñar a comunicarse = Teaching to live together, teaching to communicate

In this article we look at some of the questions related to the learning of how to live together so that we may then look more closely at the relative aspects of the learning of language. We insist on the importance of the not strictly linguistic aspects associated to the incorporation of children from immigrant families to the schools. From this point of view we underline the heterogeneous nature of the situation in which these children find themselves (in function with the social and professional situation of the family, of having been born here or not, and of having or not previous school experience in the community of origin etc). We also look at the necessary eradication of stereo types in the treating of this problem. We then discuss some strategies where there can be joint collaboration in the school for attaining these objectives

Una visión actualizada de la didáctica de la matemática en educación infantil = An up-to-date vision of pre-school mathematics teaching

This article aims to investigate pre-school mathematics teaching from an uptodate perspective. To pursue this contemporary vision we focus on four key questions: what kind of maths is being worked on, who is doing it, how it is being done, and why it is being done

Consideraciones metodológicas para la enseñanza y el aprendizaje del deporte escolar = Methodological considerations for the teaching and learning of school sport

Sport is a fundamental content in the teaching and learning of Physical Education independently of whether it is seen assuch by some authors. In whichever case according to the treatment that we give it, it will have sufficient educationalpotential without forgetting that it is the student who is the important figure in the process. To achieve the objectives wemust facilitate practices that are in agreement with the indispensable ethical principles to try to bring about a meaningfuland functional learning. The methodological criteria that we present in this article have this intention helped by examplesthat make it easier to understand the teaching learning process

Automatic evaluation and data generation for analytical chemistry instrumental analysis exercises

In general, laboratory activities are costly in terms of time, space, and money. As such, the ability to provide realistically simulated laboratory data that enables students to practice data analysis techniques as a complementary activity would be expected to reduce these costs while opening up very interesting possibilities. In the present work, a novel methodology is presented for design of analytical chemistry instrumental analysis exercises that can be automatically personalized for each student and the results evaluated immediately. The proposed system provides each student with a different set of experimental data generated randomly while satisfying a set of constraints, rather than using data obtained from actual laboratory work. This allows the instructor to provide students with a set of practical problems to complement their regular laboratory work along with the corresponding feedback provided by the system's automatic evaluation process. To this end, the Goodle Grading Management System (GMS), an innovative web-based educational tool for automating the collection and assessment of practical exercises for engineering and scientific courses, was developed. The proposed methodology takes full advantage of the Goodle GMS fusion code architecture. The design of a particular exercise is provided ad hoc by the instructor and requires basic Matlab knowledge. The system has been employed with satisfactory results in several university courses. To demonstrate the automatic evaluation process, three exercises are presented in detail. The first exercise involves a linear regression analysis of data and the calculation of the quality parameters of an instrumental analysis method. The second and third exercises address two different comparison tests, a comparison test of the mean and a t-paired test.

AVOIDING FIRST-YEAR UNIVERSITY CHEMISTRY TEXTBOOKS’ MISREPRESENTATIONS IN THE TEACHING OF SPONTANEOUS REACTIONS

This paper summarizes the misrepresentations related to Gibbs energy in general chemistry textbooks. These misrepresentations arise from a problem in the terminology textbooks use. Thus, after reviewing the proper definition of each of the terms analyzed, we present two problems to exemplify the correct treatment of the quantities involved, which may help in the discussion and clarification of the misleading conventions and assumptions reported in this study.

INTERACTIONS: DESIGN, IMPLEMENTATION AND EVALUATION OF A COMPUTATIONAL TOOL FOR TEACHING INTERMOLECULAR FORCES IN HIGHER EDUCATION

Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.

PROPOSTA EXPERIMENTAL DIDÁTICA PARA O ENSINO DE ANÁLISE DE COMPONENTES PRINCIPAIS

Principal component analysis (PCA) is a chemometric method that allows for the extraction of chemical information that would otherwise be impossible to determine. Teaching chemometrics to undergraduates can contribute to the overall professional development and training of new teachers, whose profiles have been gaining attention due to the current demand for data interpretation. In this study, a didactic experiment involving PCA is proposed. Spectrophotometry was used in the ultraviolet-visible (UV-Vis) region to assess the behavior of anthocyanins extracted from red cabbage at different pH values. The results suggest the possible separation of anthocyanin structures into three distinct groups, according to their chemical characteristics displayed in acid, neutral, and basic media. The objective is to develop educational materials targeted to undergraduate courses, which encompass a larger number of concepts and introduce instrumental techniques currently being employed in both academic research and the industrial sector. Specifically, the proposed experiment introduces concepts related to spectrophotometry in the UV-Vis range and the PCA chemometric method. The materials used are easily accessible, and UV-Vis spectroscopy equipment is less expensive in comparison with other spectroscopy methods.

Determination of copper at wide range concentrations using instrumental features of high-resolution continuum source flame atomic absorption spectrometry

This work describes a method to determine Cu at wide range concentrations in a single run without need of further dilutions employing high-resolution continuum source flame atomic absorption spectrometry. Different atomic lines for Cu at 324.754 nm, 327.396 nm, 222.570 nm, 249.215 nm and 224.426 nm were evaluated and main figures of merit established. Absorbance measurements at 324.754 nm, 249.215 nm and 224.426 nm allows the determination of Cu in the 0.07 - 5.0 mg L-1, 5.0 - 100 mg L-1 and 100 - 800 mg L-1 concentration intervals respectively with linear correlation coefficients better than 0.998. Limits of detection were 21 µg L-1, 310 µg L-1 and 1400 µg L-1 for 324.754 nm, 249.215 nm and 224.426 nm, respectively and relative standard deviations (n = 12) were £ 2.7%. The proposed method was applied to water samples spiked with Cu and the results were in agreement at a 95% of confidence level (paired t-test) with those obtained by line-source flame atomic absorption spectrometry.

Teaching mathematics and programming : new approaches with empirical evaluation

Programming and mathematics are core areas of computer science (CS) and consequently also important parts of CS education. Introductory instruction in these two topics is, however, not without problems. Studies show that CS students find programming difficult to learn and that teaching mathematical topics to CS novices is challenging. One reason for the latter is the disconnection between mathematics and programming found in many CS curricula, which results in students not seeing the relevance of the subject for their studies. In addition, reports indicate that students' mathematical capability and maturity levels are dropping. The challenges faced when teaching mathematics and programming at CS departments can also be traced back to gaps in students' prior education. In Finland the high school curriculum does not include CS as a subject; instead, focus is on learning to use the computer and its applications as tools. Similarly, many of the mathematics courses emphasize application of formulas, while logic, formalisms and proofs, which are important in CS, are avoided. Consequently, high school graduates are not well prepared for studies in CS. Motivated by these challenges, the goal of the present work is to describe new approaches to teaching mathematics and programming aimed at addressing these issues: Structured derivations is a logic-based approach to teaching mathematics, where formalisms and justifications are made explicit. The aim is to help students become better at communicating their reasoning using mathematical language and logical notation at the same time as they become more confident with formalisms. The Python programming language was originally designed with education in mind, and has a simple syntax compared to many other popular languages. The aim of using it in instruction is to address algorithms and their implementation in a way that allows focus to be put on learning algorithmic thinking and programming instead of on learning a complex syntax. Invariant based programming is a diagrammatic approach to developing programs that are correct by construction. The approach is based on elementary propositional and predicate logic, and makes explicit the underlying mathematical foundations of programming. The aim is also to show how mathematics in general, and logic in particular, can be used to create better programs.

In pursuit of an intercultural dimension in EFL-teaching : exploring cognitions among Finland-Swedish comprehensive school teachers

This thesis is about the educational purpose of foreign language teaching (FLT) in an increasingly internationalised world.The past 20-30 years have witnessed a fundamental rethinking of the aims of FLT, entailing a shift in emphasis from linguistic competence over communicative competence to intercultural competence. The growing emphasis on cultural issues, called for by research and international curricular documents, places new demandson language teachers. The overall aim of this study is to deepen the knowledge about the attitudes of teachers at the upper level of the Finland-Swedish comprehensive school towards the treatment of culture in English foreign language (EFL) teaching. The questions in focus are: 1) How do teachers interpret the concept"culture" in EFL-teaching?, 2) How do they specify the cultural objectives of their teaching? and 3) What do they do to attain these objectives? The thesis strives to reveal whether or not language teaching today can be describedas intercultural, in the sense that culture is taught with the aim of promotingintercultural understanding, tolerance and empathy. This abductive and largely exploratory study is placed within a constructivist and sociocultural framework,and is inspired by both phenomenography and hermeneutics. It takes its starting-point in language didactics, and can also be regarded as a contribution to teacher cognition research. The empirical data consists of verbatim transcribed interviews with 13 Finland-Swedish teachers of English at grades 7-9. The findings are presented according to three orientations and reviewed with reference to the 2004 Finnish National Framework Curriculum. Within the cognitive orientation, "culture" is perceived as factual knowledge, and the teaching of cultureis defined in terms of the transmission of knowledge, especially about Britain and the USA (Pedagogy of Information). Within the action-related orientation, "culture" is seen as skills of a social and socio-linguistic nature, andthe teaching aims at preparing the students for contacts with people from the target language areas (Pedagogy of Preparation). Within the affective orientation, which takes a more holistic approach, "culture" is seen as a bi-directional perspective. Students are encouraged to look at their own familiar culture from another perspective, and learn to empathise with and show respect for otherness in general, not just concerning representatives of English-speaking countries (Pedagogy of Encounter). Very few of the interviewed teachers represent the third approach, which is the one that can be characterised as truly intercultural. The study indicates that many teachers feel unsure about how to teach culture in an appropriate and up-to-date manner. This is attributed to, among other things, lack of teacher insights as well as lack of time and adequate material. The thesis ends with a set of recommendations as to how EFL could be developed ina more intercultural direction.