bluuebunny/crossref_metadata_2025 huggingface dataset:
Community Participation in Housing and Urban Development in Poor Urban Communities,Case Study of Umbadda, Khartoum
Authors: Eltahir Muna M.
Published: June 2021

Community participation represents a voluntary action carried out by community members who participate with each other in different kinds of work to achieve desired goals. Participation includes people's involvement in decision-making, in implementing programs, sharing in the benefits of development programs and their involvement in efforts to evaluate such programs. (Cohen, D. and Prusak).
According to Muhammad, community participation, known locally as nafeer or fazaa, is a deeply rooted ancient phenomenon in the Sudanese culture and has been common especially among traditional people in rural areas and villages, where it is usually men's domain (Muhammad, 1975). Community participation is affected by religious beliefs, ethnic and cultural backgrounds as well as laws, political environment, economic situation. Social relations (social capital), history and age of the neighborhood.
The present paper discusses community participation in Umbadda, Harra 14, a newly planned poor neighborhood in Greater Khartoum the capital of Sudan, which has a population of 5.5 million inhabitants growing at an annual rate of 5.6% per year. Data collection was based on a filed research carried out by the author in the summer of 2002 through intensive interviews with community leaders, and a structured household questionnaire.
Preliminary Assessment and Processing of Beach Sands along the River Nile Banks, Northern State, Sudan
Authors: A.S.Seifelnasr Ahmed , M.M. Magbua Eltahir
Published: June 2021

Several samples were collected from the beach sands accumulated in many places along the River Nile banks through the northern state, Sudan. The collected samples were subjected to microscopic, X-ray diffraction and chemical analysis. Mineralogical analysis has shown that the mineral components of those samples include magnetite, hornblende, garnet, ilmenite, rutile, zircon and monazite. Several separation techniques were also applied to separate the potential heavy minerals. The obtained results indicated that the tested beach sand samples contain substantial amounts of the potential heavy minerals, especially zircon and monazite.
Design and Development of 1.5KW Pelton Wheel Turbine
Authors: Musa Eimad Eldin Elhadi , Ibrahim Mohamed Mohamed Ahmed
Published: June 2021

This paper aims to represent a pelton wheel turbine that designed and fabricated in Omdurman Islamic University, faculty of engineering Sciences. The pelton wheel is designed using empirical formulae and its model is tested for the purpose to get its performance characteristics. The main geometric parameters which determined in this work are runner diameter, bucket size and nozzle diameter and dimension of other mechanical parts. The results which obtained by this design procedure are compared with that in available literature and they are acceptable.
Optical Fiber Communications by means of Chaos Generation
Authors: A. Rahman Osman Babiker , Awadelgied A. M. , Al Naimee Kais
Published: June 2021

The Chaos in the single-mode semiconductor lasers is generated by means of an optoelectronic feedback.
Chaotic been generation under selected experimental initial condition of semiconductor laser model with optoelectronics feedback under appropriate conditions.
MATLAB packages using to simulate the model behavior of semiconductor laser diodes with optoelectronics feedback.
The Chaos in the single-mode semiconductor lasers is generated by means of an optoelectronic feedback. And result generated due to the simulated models.
The existence of slow chaotic spiking sequences in the dynamics of a semiconductor laser with an optoelectronic feedback demonstrated experimentally and theoretically.
Beneficiation of Low-Grade and High-Phosphorus Iron Ore of Bajrawia, Sudan by Reverse Anionic Flotation: Potential of Microwave Treatment
Authors: Abbaker Ahmed Mohammedelmubarak , Moslim Eltahir Mohamed , Elsalmawy Montasir Sabbah El Din
Published: June 2021

Deposits of low grade and high-phosphorus iron ores are spreading globally, however, the usage of this kind of deposits in the manufacturing of steel bounded because of the high-phosphorus content as well as depression of iron in which affect the quality of the produced steel. The Bajrawia iron ore deposit is one of the largest in Sudan but it only contains (35.5% Fe) and undesirable amount of phosphorus (0.37% P). This paper investigated the utilization of reverse anionic flotation (RAF) for the upgrading of iron and dephosphorization. Additionally, the effect of microwave pre-treatment on forth flotation performance on a laboratory scale. Microwave pre-treatment was applied on optimized reverse anionic flotation parameters in an account of iron grade (47.31% Fe), iron recovery (86.43%) and phosphorus content (0.167% P). The findings into the microwave pre-treatment are quite promising. This investigation has revealed that microwave heating improves the flotation response of iron grade to (51.94%) and phosphorus content decreases into (0.127% P) due to increasing the liberation.
Three Different Features Based Metric To Assess Image Quality Blindly
Authors: Mahmood Saifeldeen Abdalmajeed
Published: June 2021

Abstract When creating image quality assessment metric (IQA) no confirmation all distortion types are available. Non-specific distortion blind/no-reference (NR) IQA algorithms mostly need prior knowledge about anticipated distortions. This paper introduce a generic and distortion unaware (DU) approach for IQA with No Reference (NR). The approach uses three different measuring features which are initiated from the gist of natural scenes (NS) using Log-derivatives of the parameters; a general Gaussian distribution model, two sharpness functions, and Weibull distribution. All features were analyzed and co mpared together to examine their performance. When calibrating the proposed features performance on LIVE database, experiments show they have good contribution to the state of the art IQA and they outperform the popular full-reference peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) methods. Also they show sharpness features are the best when assess both prediction monotonicity and predict accuracy evaluation among the three features categories. Besides they show asymmetric generalized Gaussian distribution (AGGD) based features have the best correlation with differential mean opinion score.
تأثير إستخدام خبث أفران مجموعة جياد الصناعية على جودة الخرسانة
Authors: حسين محمد علي علي , عبداللطيف أحمد حبيب الطيب
Published: June 2021

The need to produce high performance concrete led the researchers to try to exploit the potentialities of natural or artificial materials so as to improve the properties and performance of concrete. Slag is an industrial disposal which considered as a secondary product of pig-iron, these disposal will cause a severe harm to the environment in case of not get rid of it. In this investigation iron furnace slag which is produced at Giad Group - Iron Factory has been used as an alternative of proportion on cement after being processed, since its main oxides are similar to those of cement. In the practical part of our research slag has been added to the concrete mix in two ways, first by using it to replace as cement by weight as a substitutions of cement in different percent [10, 20, 30]% without changing in water-cement ratio [W/C], second by using the slag with the same previous percentage in addition to [15, 25]% to replace cement with reducing in water-cement ratio [W/C], and in addition superplasticizer [SP 901] has been added as percent from cement used in the mixture. The effect of slag was studied on the properties of fresh and hardened concrete including slump test and compressive strength in [7, 14, 28] days were investigated. The results show improvement in all concrete specimens for the added percentage of the slag as replacement materials and the addition of superplasticizer in the production of concrete and improvement in its properties. However, there is a gradual reduction in slump measurements due to slag percent increase in case of the two methods.
Applicability of using the 3D concrete printing technology in Sudan
Authors: Elnaeem Ruaa , Taglsir Mohammed
Published: June 2021

Three-dimensional (3D) Printing is an advanced manufacturing process that has been applied to many fields. Recently, the 3D Concrete Printing (3DCP) has been employed for construction due to its ability to produce complex shapes easily, with less human intervention and with minimum material wastage. However, there are challenging issues regarding the cost of construction and the components of concrete mixture which are not fully explored. The aim of this paper is to review the 3DCP technology and investigate the possibility of applying it in Sudan, specifically for low-cost housing. In order to meet this aim, a comprehensive review has been done to study the projects implemented worldwide using 3DCP technique. Then, some concrete mixtures have been reviewed analyze the amount of materials used in each mix. The necessary tests to ensure the, workability, Extrudability and buildability have also been specified. Then the 3DCP technique has been compared with three common construction methods in Sudan for low-cost housing those were 40 square meters area in plan. These methods are the cement blocks, the Ferrocement and the graded sand mixture.. The comparison has been made in terms of construction cost, construction duration and the man-force required. The results have shown that the 3DCP model needed the least number of construction days. However, it was the highest in terms of the cost and the second best in terms of the used labors. It has been concluded that applying 3DCP technology in Sudan is possible and could be effective in the low-cost housing projects.
اثر استخدام الرمل السيليكي على مقاومة الخرسانة
Authors: M. Adam Fathelrahman , E. A. Omer , I. Ali Mohammed , E. M. Salih
Published: June 2021

In this research, a study of using silica sand of a purity reaches 95% was done in order to know its effects on the strength of concrete when it used as an alternative to the normal sand by a different ratio of 25%, 50%, 75% and 100%. The study was done using Normal Portland Cement with a water/cement ratio of 0.52 and the mix design was done according to the British Standard Method. The ratio 1:1.5:3 was used for the different materials composed of the mix design. A reference mix design was used without containing any silica sand by means of 0% ratio of silica sand. Compression tests for the strength of concrete have been done for cubes of 7 days and 28 days age of curing and the results obtained appeared that the using of silica sand increases the concrete strength with reaching the peak at a ratio of 50% of silica sand where the strength was increased for the 7 days and 28 days by a ratio of 10% and 11% more than the strength of reference mix design respectively. Also, the study appears that the increase of silica sand by more than 50%, leads to the brittleness of concrete and this has been seen clearly when the ratio of silica sand reached 100% since the strength of concrete be down by 31% for 7 days and by 16% for the 28 days.
التدفق النقدي الاحتمالي, نموذج مونتكارلو و سلوك مدراء مشاريع التشييد فى السودان
Authors: احمد ادم ابراهيم
Published: June 2021

Construction industry in the Sudan has experienced a high or disastrous economical, financial, political and social environment during the last decade and respondents and their organizations had committed to deliver projects within deterministic costs. Inevitably, project stakeholders had been challenged by the effect of overall disastrous project risks. The research checked whether respondents were capable to manage those issues and risks efficiently and effectively. The research highlighted the effect of overall risks on a default project employing Monte Carlo simulation. 80 % of the respondents had overestimated their achievements when compared to actual projects outputs. In fact, the average respondent employed only 11 % of the researched tools and techniques, while none of the tools or techniques usage was rated as good, excellent or outstanding. It was proofed that adopting optimistic or the most likely estimates is a deterministic solution to both the project and the organization. Finally, it is recommended to train respondents and company chief executive officers in handle construction cost risks.
¿Cómo elaboramos CJP?
Authors: Tórrez Mario Isaías
Published: June 2021

Recién se publica el número correspondiente, se abre el periodo para recibir trabajos o colaboraciones del colectivo académico del Instituto Centroamericano de Estudios Jurídicos y Políticos, ICEJP-UPOLI o de nuestros colaboradores y colaboradoras nacionales e internacionales de la academia o de la sociedad civil organizada.
Centroamérica ante los retos de los procesos constituyentes:
Authors: Narváez Fidel Ernesto
Published: June 2021

Centroamérica forma parte de una de las regiones que las instituciones internacionales califican como las más desiguales e inseguras del mundo. Sin embargo, los movimientos sociales durante los últimos meses en Honduras y Guatemala han exigido una reforma del sistema político y han solicitado una respuesta democrática, popular y constituyente a la problemática social prolongada. Esto ha procurado la aparición de un tejido social homogéneo y la de un prisma de oportunidades para superar el status quo de la región. Este artículo pretende coadyuvar al fortalecimiento de ese proceso de ruptura y a la vez de transición política y democratización económica desde la perspectiva de otros países de América Latina y que integran el llamado bloque del Nuevo Constitucionalismo Latinoamericano.
Effective Regulation of the Israeli Higher Education System in the Global and Neoliberal Era
Authors: Davidovitch Nitza , Cohen Erez
Published: June 2021

For over six decades Israel’s system of higher education has been managed by the Ministry of Education and the Council for Higher Education (CHE). During this period, significant transitions have occurred in the academic system throughout the world and in Israel, leaving their mark on research and teaching and on the related regulatory agencies. The purpose of the study is to examine the need for regulation of higher education in a capitalist world, with Israel serving as a case study.

The study examines the CHE’s management of changes that occurred in the academic world and the overall considerations utilized by the pilots of this regulatory agency, which led to shaping policy from a perspective of time and with an eye to the challenges of the future, in comparison to supervisory agencies around the world. The research method is based on research literature addressing the system of higher education in Israel and elsewhere as well as on interviews with senior academics occupying key positions in the CHE in the past and present. The research findings indicate that the CHE has a bureaucratic image, a short-sighted policy, and that it reacts to events more than leading them, as opposed to its declared goal of promoting high standard, innovative, and accessible research and teaching processes to benefit the economy and society.

The conclusion generated by the research findings is that implementation of a hybrid model suitable for the twenty first century, which combines liberalization and regulation, should be explored. This model will let institutions of higher education develop independently while reducing government supervision, and will allow the regulatory body to regulate their activity via incentives and restrictions, while identifying market failures that it will define. Such a regulatory body will include an array of academic experts from the field of higher education with proven experience in the fields of academic research and teaching, in order to separate the managing of Israel’s system of higher education from politics and bureaucracy.
Predicting the Risk of Insolvency in Small Enterprises: Critical Analysis of the Predictive Model Associated with the New Italian Code of Business Crisis
Authors: Maria Arcari Anna , Grechi Daniele
Published: June 2021

Numerous studies have been conducted to verify whether, and under what conditions, Altman's Z-Score model can also be applied to unlisted, non-US companies. The response of numerous studies confirms the substantial validity of this algorithm. However, in Italy, the legislator, in launching the new Business Crisis Code in 2019, in adherence to an important European recommendation, did not adopt the aforementioned model but approved a different one. In order to find a justification for this choice, the present work intends to test the effectiveness of the warning indices that will be adopted in Italy by comparing them with the Altman predictive model in the Z'' Score version. To this end, the two models were applied to the balance sheets of 789 Italian firms that went bankrupt in the period 2016-2018 and, at the same time, to a control sample, equal in number and composition, of non-bankrupt firms.

The results of this analysis produced two distinct findings. The Italian method proved to be less effective in predicting a crisis than the Z'' score. but more effective in determining whether a firm is truly healthy. This evidence is useful to confirm once again the effectiveness of the Z'' Score in a non-American context but also, and above all, to provide suggestions to the Italian legislator so that it can refine the predictive model currently in force.
¿Utilizan los alumnos esquemas conceptuales en la interpretación del sonido?
Authors: Saura Llamas Octavio , Pro Bueno Antonio de
Published: June 2021

The origin of this work can be traced to investigations that have centred on the students’ previous knowledge that conditions their learning process. There are, however, two aspects which must be taken into account: firstly, to know about the students’ previous ideas should no be considered as an end in itself but as the starting point towards deliberate intervention and, secondly, when someone uses his knowledge, he does it with conceptual structures and with certain strategies related to them.Our work concentrates on the identification of the students’ ideas (both conceptual and procedural) about one of the few areas to which not many contributions have been made: the learning of sound. We attempt to identify the possible schemes the students use in their interpretation of aspects related to their everyday life. Finally, we establish certain implications for the teaching of these contents in compulsory secondary Education.
Estrategia visual en la generalización de pautas lineales
Authors: García Cruz Juan Antonio , Martinón Antonio
Published: June 2021

In this paper the role played by the drawing included in linear generalizing problems is outlined. The main focus is on the generalization developed by secondary education students. The research has been conducted over a population of 13 to 18 year old students. A visual strategy is identified and some modalities described. The Dorfler theoretical framework for the process of generalization is used to analize the students behaviour. Finally we conclude with some didactical remarks.
La V epistemológica aplicada a algunos enfoques en resolución de problemas
Authors: Escudero Consuelo , Moreira Marco Antonio
Published: June 2021

This paper includes a technique to apply a simplified Gowin’s Vee as a reference tool to analyse four different trends which are useful for research in Physics problem solving. They are: a) the strategy alternative; b) the problem solving in accordance with scientific methodology; c) the problem solving and its social environment and d) the problem solving in Science and Technology with a practical proposal. Its analysis shows the way it can be used for the classroom.
Por una concepción moderna de la enseñanza de la física
Authors: Ramal Zea José Mª
Published: June 2021

In this paper it is suggested how to approach, from a modern viewpoint, some questions, which are usually worked in the Physics lessons. Some particular activities are proposed and discussed.
Algunas dificultades en torno a la conservación de la energía
Authors: Solbes Jordi , Tarín F.
Published: June 2021

The subject of energy is a very important part of a physics course, as it provides a clear link between the different sections of physics. In this paper we analyze the teaching and learning of energy at secondary level and we show that traditional methods to teach energy: a) do not consider students misconceptions, b) introduce energy conservation in mechanics and thermodynamics but do not clarify if it is a theorem or a principle, and c) do not present the conservation of energy as a general principle of the whole physics. Finally, a new approach to energy teaching is showed.
Educación ambiental: de la acción a la investigación
Authors: Mayer Marc
Published: June 2021

Environmental education has developed greatly over the last twenty years, reflecting upon the deep contradiction between the need for human development, which means the need for scientific development and a global market economy, and the need for a better quality of life and natural environment. In the educational proposals, the action for the environment is no more separated from a deeper understanding of the way we think and from the importance given to the emotional links with our planet. This wiser way to conceive environmental education is strongly concerned with the complexity of thought and the «reductionism» implicit in many pedagogical theories and environmental claims. Environmental education could become a new way to look at education, putting together the complexity theories, the importance of making sense of ignorance and uncertainty, and the need of constructing and comparing values. This new way to conceive education claims new educational structures and consistent strategies to use in research and evaluation: the action carried out all over the world in the last years indicates the issues and the strategies environmental education research has to face.
Errores comunes sobre relatividad entre los profesores de enseñanza secundaria
Authors: Alemany Berenguer Rafael Andrés
Published: June 2021

The limited understanding of the Principle of Relativity and its vague and ambiguous formulation in most text-books, may be some of the sources of very common misconceptions on explaining this outstanding piece of the 20th century science. To diagnose these misconceptions a general check of many of books was carried out with the results that are expounded in this work. The conclusions revealed that mistakes emerged through misunderstanding of modern physics assumptions about the proper nature of reality, and difficulty in transfehng those new ideas to operative thought in order to achieve an effective learning.
Una revisión del movimiento educativo ciencia-tecnología-sociedad
Authors: Membiela Pedro
Published: June 2021

In this paper I present a revision of the Science-Technology-Society movement, its origins, historic development and relations with science education. Comments are made about research carried out on teacher and student opinions about this subject, and the different integration models of STS in the school curriculum. A constructivist curriculum development model is presented and questions related to content selection are considered, as well as teaching models and the conditions that curriculum materials need to fulfill to be considered as STS. Finally, a short revision of the present situation of the STS movement in Spain is made.
Evolución de las representaciones mentales sobre colisiones
Authors: Villani Alberto , Orquiza de Carvalho L.
Published: June 2021

The article concerns the results of a qualitative research with secondary school students on the evolution of their ideas about collisions in mechanics. We focus our attention on the mechanism of partial attainment of new ideas and the relationship between the resistance to change and the experimental situations. Some implications for teaching are also discussed.
Análisis de los trabajos prácticos de química general en un primer curso de universidad
Authors: Insausti M. J.
Published: June 2021

Learning in the laboratory has been and still is a highly controversial issue among science educators although there are not many studies carried out in Spanish Universities. This paper reports an evaluation of the cunent situation in a Laboratory of General Chemistry.For the purpose of this research, a model of learning has been adopted and an evaluation of students attitude towards the Practical Works has been made.
Dificultades en la enseñanza-aprendizaje de los problemas de física y química. II. Opiniones del profesor
Authors: Oñorbe de Torre A. , Sánchez Jiménez J. M.
Published: June 2021

Analysing the ideas with which teachers and pupils confront problems in physics and chemistry. The starting point for this analysis is the compilation of difficulties and causes of failure involved in solving problems raised in a didactic investigation of the subjects.This second part-referring to the teachers- shows the relationships between difficulties faced as well as distinguishing between groups of teachers who share similar ideas about problem solving education. Finally a comparison is made between the two sections -teachers and pupils- with implications to teaching and learning.
Estudios sobre consistencia en las ideas de los alumnos en ciencias
Authors: Oliva Martínez José Mª
Published: June 2021

This article reviews the different lines of research related to the studies about «consistency» in the ideas as expressed by students, a highly interesting concept both from the theoretical and practical standpoints.
Una aproximación empírica a través de las relaciones Ciencia-Tecnología- Sociedad (CTS, en estudiantes de secundaria y universitarios valencianos
Authors: Borreguero P. , Rivas F.
Published: June 2021

The study reveals the Science -Technology -Society (STS) outlooks of high school students and university students. The VOSTS inventory (Aikenhead et al., 1989) was used to reflect The STS beliefs, positions and literacy. The outcomes of the study point to the need of introducing new concepts and attitudes, emphasizing epistemology, information and cognition.
El trabajo práctico. Una intervanción para la formación de profesores
Authors: García S. , Martínez M. C. , Mondelo Alonso Matilde
Published: June 2021

In this article we raise and discuss the field of teacher training with regard to practical work. We take as a point future teaching staff on one instructuve possibility of the aforementioned pract.
Problemas de terminología en estudios realizados acerca de "lo que el alumno sabe" sobre ciencias
Authors: Jiménez Gómez Emma , Solano Martínez Isabel , Marín Martínez Nicolás
Published: June 2021

In this paper we have carried out a bibliographic review of the terms currer tly used by science education researchers to describe «pupils' knowledge» of Science. Further, we have analised their meanings from the perspective of the methodological framework used and have offered our own proposal, as a result of that review, so as to reach a consensus on both the terminology and the possible range of meanings to be used. It must be pointed out that we have excluded those studies which discuss «pupils' knowledge» from a purely psychological perspective because of the enormous amount of bibliography on this topic.
Historia, filosofía y enseñanza de las ciencias: la aproximación actual
Authors: Matthews M. R.
Published: June 2021

This paper traces the use of, and arguments for, the history and philosophy of science in school science courses. Specific attention is paid to the British National Curriculum proposals and .:o the recommendations of the US Project 2061 curriculum guidelines. Some objections to the inclusion of historical material in science courses are outlined and answered. Mention is made of the Piagetian thesis that individual psychoIog: cal development mirrors the development of concepts in the history of science. This introduces the topic of idealisation in science. Some significant instances are itemised where science education has, at its considerable cost, ignored work in philosophy of science. Arguments for the inclusion of the history and philosophy of science in science teacher education programmes are given. The paper finishes with a list of topical issues in present science education where collaboration between science teachers, historians, philosophers, and sociologists would be of considerable benefit.
El paradigma de las concepciones alternativas y la formación de los profesores de ciencias
Authors: Vázquez Alonso Ángel
Published: June 2021

The pre -service education of science teachers is empirically studied in the framework provided by the paradigm of alternative conceptions by means of 13 simple usual Physics questions. The rates of pre -service teachers' alternative conceptions show a strong resemblance with those found in previous research even with students. Differences between sex and age groups are remarkable, but the major finding is that only physicists show a suitable pattern lacking alternative conceptions about Physics topics, while other science careers not only have a lot of alternative conceptions but also science and non -science teachers show similar patterns. We claim a pre -service teacher education more based on conceptual change aimed to avoid teachers' alternative conceptions in basic science contents of different areas.
Evolución de los conceptos ácido-base a lo largo de la enseñanza media
Authors: Bardanca M. , Nieto M. , Rodríguez Mª C.
Published: June 2021

The aim of this paper is to know the evolution of the concept of acids and bases throughout the different courses of Secondary School.
La resolución de problemas: una revisión estructurada
Authors: Perales Palacios F. Javier
Published: June 2021

The aim of this paper is to review and organize the background, historic development and present situation of problem-solving research on Sciences and Mathematics.
Técnicas de creación y manipulación de imágenes de estructuras orgánicas tridimensionales. Nuevos entornos de aplicación didáctica
Authors: Juanes J. A. , Zoreda J. L. , Vacas Peña José Manuel , Riesco J. M. , Vázquez R.
Published: June 2021

The development of computer -generated images opens new perspectives in the field of teaching. These techniques permit geometric modelling of three-dimensional structures, allowing the production and manipulation of real images and the numerical and graphic characterization of two -three-dimensional contours. The procedure proposed is based on the manipulation, by geometric (turns, traslations) and algebraic (addition, intersection) operations, of an initially finite set of surfaces (elipsoids, paraboloids, cylinders and planes), defined by their parameters, for teaching purposes.
Diseño de unidades didácticas en el área de Ciencias Experimentales
Authors: Sánchez Blanco Gaspar , Valcárcel Pérez María Victoria
Published: June 2021

This study puts forward some planning strategies for the teaching of Science based on a constructivist approach for the teaching/learning process. These strategies are shown in a model for the design of teaching units which includes five interdependent tasks: scientific analysis, pedagogical analysis, selection of objectives, selection of pedagogical strategies and selection of evaluation strategies. The first two aim at the reflection and estimation of contents and constrains of the teaching/learning processes. The other three are concerned with teachers' decision making and the explicitness of their teaching plans, as well as with their classroom performance in order to achieve them.
¿Cuál brilla más?: predicciones y reflexiones acerca del brillo de las bombillas
Authors: Sebastià José M.
Published: June 2021

This work analyses the extension, consistency and stability of university students' interpretations concerning electric circuits. We also develope some theoretical considerations about the origin of the students' interpretations and their possibilities of transformation and change.
Lenguaje literal y connotado en la enseñanza de las Ciencias
Authors: Lahore Alberto A.
Published: June 2021

This article intends to be a reflection on the function of language in science learning, and a possible explanation of the difficulties encountered by students in the use and interpretation of scientific language.
El papel del péndulo en la construcción del paradigma newtoniano
Authors: Solaz Portolés Joan Josep , Sanjosé López V.
Published: June 2021

This paper shows the important role of one of the most common instruments, the pendulum, in the construction of the newtonian paradigm. From the analysis of some interesting applications carried out by the greatest scientists of that time, we conclude that the appropriate use of the pendulum in the classroom can be an easy way to introduce historical and epistemological evolution of basic physical concepts.
Estrutura interna de testes de cohecimento em Física: um exemplo em mecânica
Authors: Lang da Silveira F. , Moreira Marco Antonio
Published: June 2021

Research findings are presented concerning the internal structure analysis of a multiple choice test constructed to detect whether or not the student has the Newtonian conception of the interrelationship between force and motion. These findings show that the test has two different but related factors: one subset of items checks students' ability to identify forces in certain physical situations according to the Newtonian view while another subset checks whether or not they relate the resultant force with acceleration. In addition, the analysis also shows that the two subsets have slightly different predicting power concerning student performance in mechanics. This kind of analysis might be very relevant for teacher's work regarding learning evaluation.
Estrategias y argumentos en el estudio descriptivo de la asociación usando microordenadores
Authors: Batanero Bernabeu Carmen , Estepa Castro José Antonio , Díaz Godino J.
Published: June 2021

In this work, problem solving procedures about statistical variables association using microcomputers are analysed. The effect of several didactical variables on these procedures is also studied. The studied population consisted of 18 prospective teachers who had been previously trained for 7 weeks. By studying the students' replies we determined their ideas of the scope and meaning of the term «association» and derived criteria for construction of new didactic situations.
Ayudar a los alumnos a aprender cómo aprender. La opinión de un profesor-investigador.
Authors: Novak J. D.
Published: June 2021

Four basic questions are approached in this paper: I. What we know about how people learn. 2. How we can help students learn to learn. 3. What the obstacles are to helping students learn. 4. What the expectations are for the empowerment of people. The answers, based on the author's experience and on research done at Cornell University refer widely to significant learning, to heuristic learning and to the conceptual maps.
Un ejemplo de aportación de la didáctica de la física a la enseñanza: los ejercicios cualitativos y los razonamientos funcionales
Authors: Saltiel E.
Published: June 2021

Didactic specialists use exercises as a resource for research, whereas for teachers they are resources for teaching and evaluating. In most cases the evaluative exercises are of a quantitave type and the didactic value of the exercises of a qualitative type is not clearly shown. Starting from the analysis of the answers to exercises on the same subject but of different types, the author shows how important qualitative exercises are and how they can he used as resources for teaching and evaluating.
El conocimiento acerca de las matemáticas y las prácticas de enseñanza
Authors: Sánchez García Mª V. , Llinares Ciscar Salvador
Published: June 2021

The individual and contextual influences that two periods of school experience have over the way in which two prospective teachers build their personal view of Mathematics and its teaching are studied. In particular, the important role played by the perceived knowledge of the subject matter knowledge is shown. Also, the strategies used in trying to give coherence and meaning to the experimented changes are discussed.
Ideas de los alumnos acerca del mol. Estudio curricular
Authors: García Martín J. P. , Pizarro Galán A. Mª , Perera Cendal F. , Martín Díaz M. J. , Bacas Leal P.
Published: June 2021

In this paper a display is made of the controversy about the concept of mol and the convenience of introducing it in the school "curricula" at the age in which nowadays is made. The results we have obtained from the research carried out on the difficulties experienced by 15 to 19 year old students in understanding this concept and other related concepts are given.
Una analogía térmica para la enseñanza de la corriente continua en electricidad : descripción y evaluación
Authors: Dupin J. J. , Joshua S.
Published: June 2021

This paper reports the application of thermical analogy to the teaching of electrical current to secondary students. At the same time the students' cognitive processes on this subject are commented.
Problemática, metodología y teoría: el recorrido de un grupo de investigación en enseñanza de las ciencias
Authors: Díbar Ure M. C.
Published: June 2021

This paper discusses some results obtained from research on the teaching of mechanics to initial university courses in Brazil, together with the epistemological problems arising.
Análisis de la resolución de problemas como estrategia de enseñanza de la biología
Authors: Sigüenza Molina Agustín Francisco , Sáez Mª J.
Published: June 2021

Solving -problems as a biology teaching strategy could make the process of comprehension easier and lead to the student's acquisition of knowledge. This paper analyses problem -solving as a basic element of the above strategy (method). For this reason it first proposes the definition of the terms «problem» and «problem -solving» inside practical teaching and secondly discusses the nature of solving as a method within the particular case of biology teaching learning.
Importancia de la química descriptiva en la enseñanza de la química. Propuesta de un modelo para su aprendizaje.
Authors: Quílez Pardo J. , Llopis R.
Published: June 2021

This paper tries to establish a methodology for teaching Descriptive Chemistry by applying basic principles and the social dimension of Chemistry in a stimulating way. The selection of ammonia for this purpose is based on these assumptions.
El concepto de geosinclinal tras la revolución movilista: otro desajuste entre la ciencia actual y la ciencia en el aula
Authors: Anguita Francisco
Published: June 2021

A revision of Geology and Physical Science textbooks widely used at high-school level shows that the geosyncline idea (in itself or as a part of plate tectonics theory) is frequently presented as a tenable hypothesis on mountain origins. As this is not a scientifically acceptable position any more, a great deal of confusion is probably being created among both students and teachers without very solid geologic foundations.
Plus ça change" : los efectos de la región, número de asignaturas de ciencias cursadas y sexo sobre la opinión de los estudiantes canadienses en cuestiones de Ciencia, Técnica y Sociedad
Authors: Ryan Alan G.
Published: June 2021

An analysis of Canadian high school students' views on science -technology -society issues was undertaken in order to see if educationally significant differences in response were attributable to changes in three variables. The variables were: the region in which the students lived, the number of science courses being taken by the responding students, and the sex of the responder. On the whole, few variations among students' responses were found. The variations reported in the paper included the findings that Maritimer students tend to have a more idealistic view of how scientists conduct their work, that students who are taking three science courses have a greater understanding of the role of models in science, and that males, apart from a small group of male chauvinists, offer the same reasons as females to explain why there are fewer Canadian female scientists than males.
Ideas de los alumnos sobre la digestión : aspectos fisiológicos
Authors: Banet Hernández Enrique , Núñez Francisco
Published: June 2021

In this article we report the ideas owned by students from different levels (EGB, BUP, Teacher Training College) as well as by some teachers, in relation to certain concepts involved in the processes of digestion and substance absorption. The dificulties observed in the conceptualization of several processes, especially in lower lever students, show the need for a change in the teaching planning.
Las tareas razonadas en ciencias
Authors: Hierrezuelo Moreno José , Molina González E.
Published: June 2021

In this paper we present the development of the reasoning level of 15-17 years old pupils using the Science Reasoning Task. Some consequences for science education are presented.
Un enfoque constructivista para el desarrollo del currículo en ciencias
Authors: Driver R.
Published: June 2021

The differences between children's ideas and scientific thinking gives us some indication of the types of changes and the magnitude of those changes which we may be attempting to promote in young people's understanding during school years. In this paper 1 will review how such changes might be promoted and consider implications for curriculum planning.
El fracaso en la resolución de problemas de Física : una investigación orientada por nuevos supuestos
Authors: Gil D. , Martínez-Torregrosa y Senet F.
Published: June 2021

This paper shows an attempt to question the usual way of teaching problem solving and to elaborate more effective theoretically based proposats. Some results of the applications of new orientations are included.
Esquemas conceptuales previos de los alumnos en Geología
Authors: Granda A.
Published: June 2021

The presence of conceptual errors or pre -scientific ideas about Geology in our students runs parallel to what they sustain about other sciences: we observe not only their persistence but also their similarity to concepts/theories from previous scientific periods.
Opiniones de los adolescentes respecto al cambio sustancial de las reacciones químicas
Authors: Carbonell F. , Furió-Mas Carles
Published: June 2021

This paper deals with the problem of what our students, aged 13-18, think about the non -permanence of reactives in two familiar chemical processes and the conceptual interpretations put forward by students before an elementary chemical reaction.
¿Ingresan los alumnos a la Universidad con un adecuado desarrollo de los niveles de razonamiento?
Authors: Braga I. L.
Published: June 2021

Most of the students that enrol in the area of physical sciences and mathematics, in the Universities in Chile fail in the first courses of physics and mathematics. To try to solve this problem a course on intellectual development was devised; the contents and outcome of this course are presented.
Los científicos y sus actitudes políticas ante los problemas de nuestro tiempo
Authors: Polo Conde F. , López Cancio J. A.
Published: June 2021

In this paper, personal memories of famous scientists and their positions with regard to some problems as world war, disarmement, space race,... which affect to what is generally known as «the responsibility of the scientist» are analysed.
Representaciones de los alumnos en Biología: estado de la cuestión y problemas para su investigación en el aula
Authors: Serrano T.
Published: June 2021

Within the current perspective of the students' alternative frameworks research, the number of physic concepts investigated is far superior and better known than the biological ones; thus, a general aim of this paper is to outline some of the work done in the latter area. There are two sections in this paper. The first presents a main selection of the research done into biological topics with a more detailed analysis of the studies related to students' conceptions of heredity. A central feature of this analysis is to point out the underlining learning theories held by researchers and their selection of research designs and techniques accordingly. The significance of these studies for teachers are sketched. The second section outlines: first, some difficulties regarding the process and interpretation of the research results, and second, the scarcity of class intervention studies.
¿Qué se pretende en los laboratorios de física universitaria?
Authors: Sebastià José M.
Published: June 2021

The purpose of this article is to show the results of an analysis done, from a student's and teacher's point of view, on the objetives of the physics laboratory at the university. From a sample of 128 students and another one consisting of 20 teachers, 20 possible objectives of physics laboratory were classified according to the importance that both students and teachers thought should be given to each of the suggested objectives, and on the importance which is being given to them at the moment. A contrastive study was also done of the results obtained from both samples, showing a high correlation in the ideal objectives of the laboratory and a consistent diagnosis in reference to the working situation at the moment.
Método activo en química de COU
Authors: Seminario Permanente de Física y Química Equip
Published: June 2021

In this paper we analize the results of several pupils' classes of C.O.U. in Chemistry that have followed an experimental methodology, comparing them with those achieved by one class that has followed a traditional teaching method. As for «the Test to enter the University)) we have also made a comparison between the results obtained by our experimental classes and the rest of the pupils that have not followed this experimental method.
Ciencia y construcción del pensamiento
Authors: Moreno Marimón Montserrat
Published: June 2021

Two didactic approaches are considered in this paper: the direct transmission of knowledge and the constructivist model, with an analysis of the conceptions they imply on intelligence and how it works. The contribution that the evolution of science itself may bring to the process of individual learning is autlined.
Las orientaciones actuales de la didáctica de las ciencias experimentales en España (1985)
Authors: Mata A. , Anta C.
Published: June 2021

Trends in science education by applying a bibliometric analysis to de Spanish bibliographic production published in 1985 are presented.
¿Qué aprendemos de las semejanzas entre las ideas históricas y el razonamiento espontáneo de los estudiantes?
Authors: Saltiel E. , Viennot L.
Published: June 2021

Many studies are now available concerning the intuitive ideas of children and students in Science, and a large number of these also refer to difficulties encountered in the historical development of theories. This is especially the case in mechanics, which gave rise to parallels between students' misconceptions and Aristotle's or preclassical theories. It is very common to qualify, even with no special justification, such and such intuitive response «Aristotelian». The questions discussed in this paper are the following: —to what extent are such parallels justified? Fot instance, is there a stage in the historical development of mechanics theories which fits the spontaneous reasoning of our students?—At a second level, what are the implications of such a parallel and what do we learn from this? Does it really help us interpret students' responses and to what extent does it guide our teaching strategies?