The nature of an object-oriented program:how do practitioners understand the nature of what they are creating?

Object-oriented programming is seen as a difficult skill to master. There is considerable debate about the most appropriate way to introduce novice programmers to object-oriented concepts. Is it possible to uncover what the critical aspects or features are that enhance the learning of object-oriented programming? Practitioners have differing understandings of the nature of an object-oriented program. Uncovering these different ways of understanding leads to agreater understanding of the critical aspects and their relationship tothe structure of the program produced. A phenomenographic studywas conducted to uncover practitioner understandings of the nature of an object-oriented program. The study identified five levels of understanding and three dimensions of variation within these levels. These levels and dimensions of variation provide a framework for fostering conceptual change with respect to the nature of an object-oriented program.

Establishment of a reedbed within a created surface water fed wetland nature reserve

In the early 1990's, outline designs for two wetland nature reserves were being prepared: the Teeside International Nature Reserve (TINR) and the Cardiff Bay Barrage Environmental Compensation Measures at Redwick, Gwent. The initial design for both proposals identified reedbed as a desirable habitat for establishment. The initial design works identified the importance of reedbed evapotranspiration [ET(Reed)] within the water budget, however, literature searches identified a paucity of information on this parameter. Field experiments for the measurement of ET(Reed) from Phragmites australis are described for three sites distributed across England and Wales. Reference Crop Evapotranspiration (ETo) was calculated using techniques recommended by the Food and Agriculture Organisation. A technique for the calculation of a reedbed crop coefficient [Kc(Reed)[, from ET(Reed) and ETo data is discussed. Kc(Reed) values produced in the project were found to be similar to those developed previously in continental Europe. Mean monthly and crop development stage Kc(Reed) values are presented which are applicable in the UK and possibly worldwide. A conceptual hydrological model of surface water fed reedbed systems is developed, and used to calculate the hydrological sustainability of reedbed creation areas in the UK. Finally, the water budget model is verified using data from a small clay catchment located on the TINR. In addition, a methodology is developed for the hydrological design of surface water fed reedbed systems, and recommendations required for the feasibility, design and establishment stage of reedbed creation sites. Further research needs are also identified.

Systemological Knowledge-based Technology for Solving Complete Ill-structured Problems

Original method and technology of systemological «Unit-Function-Object» analysis for solving complete ill-structured problems is proposed. The given visual grapho-analytical UFO technology for the fist time combines capabilities and advantages of the system and object approaches and can be used for business reengineering and for information systems design. UFO- technology procedures are formalized by pattern-theory methods and developed by embedding systemological conceptual classification models into the system-object analysis and software tools. Technology is based on natural classification and helps to investigate deep semantic regularities of subject domain and to take proper account of system-classes essential properties the most objectively. Systemological knowledge models are based on method which for the first time synthesizes system and classification analysis. It allows creating CASE-toolkit of a new generation for organizational modelling for companies’ sustainable development and competitive advantages providing.

The B-Terminal Busy Probability Prediction

In the teletraffic engineering of all the telecommunication networks, parameters characterizing the terminal traffic are used. One of the most important of them is the probability of finding the called (B-terminal) busy. This parameter is studied in some of the first and last papers in Teletraffic Theory. We propose a solution in this topic in the case of (virtual) channel systems, such as PSTN and GSM. We propose a detailed conceptual traffic model and, based on it, an analytical macro-state model of the system in stationary state, with: Bernoulli– Poisson–Pascal input flow; repeated calls; limited number of homogeneous terminals; losses due to abandoned and interrupted dialling, blocked and interrupted switching, not available intent terminal, blocked and abandoned ringing and abandoned conversation. Proposed in this paper approach may help in determination of many network traffic characteristics at session level, in performance evaluation of the next generation mobile networks.

Invasive exotic plant indicators for ecosystem restoration: An example from the Everglades restoration program

We have developed a comprehensive ecological indicator for invasive exotic plants, a human-influenced component of the Everglades that could threaten the success of the restoration initiative. Following development of a conceptual ecological model for invasive exotic species, presented as a companion paper in this special issue, we developed criteria to evaluate existing invasive exotic monitoring programs for use in developing invasive exotic performance measures. We then used data from the selected monitoring programs to define specific performance measures, using species presence and abundance as the basis of the indicator for invasive exotic plants. We then developed a series of questions used to evaluate region and/or individual species status with respect to invasion. Finally, we used an expert panel who had answered the questions for invasive exotic plants in the Everglades Lake Okeechobee model to develop a stoplight restoration report card to communicate invasive exotic plant status. The report card system provides a way to effectively evaluate and present indicator data to managers, policy makers, and the public using a uniform format among indicators. Collectively, the model, monitoring assessment, performance measures, and report card enable us to evaluate how invasive plants are impacting the restoration program and how effectively that impact is being managed. Applied through time, our approach also allows us to follow the progress of management actions to control the spread and reduce the impacts of invasive species and can be easily applied and adapted to other large-scale ecosystem projects.

Concept maps as a tool to analyze the ideas of teacher training students regarding what to teach on human nutrition in Primary Education

Concept maps are a technique used to obtain a visual representation of a person's ideas about a concept or a set of related concepts. Specifically, in this paper, through a qualitative methodology, we analyze the concept maps proposed by 52 groups of teacher training students in order to find out the characteristics of the maps and the degree of adequacy of the contents with regard to the teaching of human nutrition in the 3rd cycle of primary education. The participants were enrolled in the Teacher Training Degree majoring in Primary Education, and the data collection was carried out through a training activity under the theme of what to teach about Science in Primary School? The results show that the maps are a useful tool for working in teacher education as they allow organizing, synthesizing, and communicating what students know. Moreover, through this work, it has been possible to see that future teachers have acceptable skills for representing the concepts/ideas in a concept map, although the level of adequacy of concepts/ideas about human nutrition and its relations is usually medium or low. These results are a wake-up call for teacher training, both initial and ongoing, because they shows the inability to change priorities as far as the selection of content is concerned.

Welke Constructen Zijn van Invloed op Attitude van Leerkrachten om Samenwerkend Leren in te Zetten als Instructiestrategie?

Lugtenberg, S. (2016)Welke Constructen Zijn van Invloed op Attitude van Leerkrachten om Samenwerkend Leren in te Zetten als Instructiestrategie? Mei, 17, 2016, Heerlen, Nederland: Open Universiteit

The use of motivational interviews by nurses to promote health behaviors in adolescents: a scoping review protocol

Adolescents - defined as young people between 10 and 19 years of age1 - are, in general, a relatively healthy segment of the population.2 However, the developmental changes that take place during adolescence may affect their subsequent risk for diseases and for a variety of health-related behaviors. In fact, early onset of preventable health problems (e.g. obesity, malnutrition, STDs) and the engagement in health risk behaviors (e.g., sedentary life style, excessive alcohol consumption, unprotected sex) during adolescence, are likely to put them at greater risk for physical and mental health problems at a later stage in life. Moreover, health related problems and health risk behaviors may disrupt adolescents' physical and cognitive development and therefore may affect their ability to think and act in relation to decisions about their health in the future.1 In summary, health-related behaviors in adolescence, apart from their influence on the continuum of "health-disease", they also have the potential to influence future behaviors. In fact, several studies have shown that past behaviors are good predictors of future behaviors .3,4 Thus, promoting healthy practices during adolescence and taking measures to better protect young people from health risks are essential for the prevention of health problems in adulthood.5 According to the World Health Organization, the main problems affecting young people include mental health problems (such as behavioral disorders, eating disorders, suicide, anxiety or depression), the use of substances (illegal substances, alcohol and tobacco), interpersonal violence, nutrition (a proper nutrition consists of healthy eating habits and physical exercise), unintentional injuries (which are a leading cause of death and disability among young people, with road traffic injuries accounting for about 700 deaths per day), sexual and reproductive health (for example, risky sexual behaviors, early pregnancy and childbirth) and HIV (resulting from sexual transmission and drug injection).5,6 On the other hand, the number of children and youth with chronic health conditions has increased dramatically in the past four decades7 as larger numbers of chronically ill children survive beyond the age of 10.8 Despite the lack of data on adolescents' health making it difficult to determine the prevalence of chronic illnesses in this age group9, it is known that one in ten adolescents suffers from a chronic condition worldwide.10 In fact, national population based studies from Western countries show that 20-30% of teenagers have a chronic illness, defined as one that lasts longer than six months.8 The most prevalent chronic illness among adolescents is asthma and the one with the highest incidence is diabetes mellitus, particularly type II.9 Traditionally, healthcare professionals have been mainly investing in health education activities, through the transmission of knowledge with a view to creating habits, customs and behaviors, and promoting healthy lifestyles. However, empowering people does not only consist of giving them the right information11 , i.e. good information is not enough to cause people to make changes.12 The motivation or desire to change unhealthy behaviors and habits depends on many factors, namely intrinsic motivation, control over personal decisions, self-confidence and perception of effectiveness, personal ambivalence, and individualized assistance.12 Many professionals assume that supplying knowledge is sufficient for behavioral changes; however, even very good advice often fails to generate behavioral change. After all, people continue to engage in unhealthy behaviors despite clearly knowing what they should do and how to change. "What is lacking is the motivation to apply that knowledge".13, p.1233 In fact, behavioral change is a complex phenomenon with multiple determinants that also includes motivational variables. It is associated with ambivalent processes expressed in the dilemma between keeping the current status and moving on to new ways of acting. For example, telling adolescents that if they keep on engaging in a certain behavior, they are increasing the risk of developing a long-term condition such as cardiovascular disease, stroke or diabetes is rarely enough to trigger the desired behavioral change; people are more likely to change when they believe that the change is really effective and that they are able to implement it.12 Therefore, it is essential to provide specific training for "healthcare professionals to master motivational techniques, avoid confrontation with the users, and facilitate behavioral changes".14 In this context, motivating patients to make behavioral changes is also an important nursing task where change in lifestyle is a major element of patients' treatment and preventive interventions.15 One of the nurse's goals is to help improve a patient's health or help them to manage existing health conditions. Once nurses are in a position where they have to focus on accomplishing tasks and telling patients what needs to be accomplished16, the role of the nurse is expanding even more into the use of motivational strategies.17 MI is bringing nurses back to therapeutic communication and moving them closer to successful health promotion and disease management, by promoting behavior change and empowering their patients. As the nursing profession evolves, MI is seen as a challenge and the basis of nurse's interactions with individuals, families and communities.16, 17 In the same way, MI may be taken as an essential tool in the provision of nursing care to adolescents, being itself a workspace with possible therapeutic effects regarding problems, clarification of doubts, and development of skills.18 In fact, MI may be particularly applicable in work with adolescents because of their specific developmental stage. Adolescents attempt to establish their own autonomy and identity while struggling with social interactions and moral issues, which leads to ambivalence.19 Consistent with the developmental challenges during adolescence, "MI explicitly honors autonomy, people's right and irrevocable ability to decide about their own behavior"20 while allowing the person to explore possibilities for change of risky or maladaptive behaviours.19 MI can be defined as a directive, client-centred counselling style for eliciting behavior change by helping clients to explore and resolve ambivalence. It is most centrally defined not by technique but by its spirit as a facilitative style of interpersonal relationship.21 It is a set of strategies and techniques widely used in clinical practice based on the transtheoretical model of change. The Stages of Change model describes five stages of readiness—precontemplation, contemplation, preparation, action, and maintenance—and provides a framework for understanding behavior change.22 The MI has been widely tested and applied in different areas, such as modification of addictive behaviors, interventions with offenders in the context of justice, eating disorders, promotion of therapeutic adherence among chronic patients, promotion of learning in school settings or intervention with adolescents at risk.18,23 In general, clinical practice has been adopting the perspective of motivation as something relatively immutable, i.e., the adolescent is either motivated for change/treatment and, in these conditions, the professional's role is to help him/her, or the adolescent is not motivated and then change/treatment is not feasible. Alternatively the theoretical model underlying the MI technique postulates that the individual's adherence to change/treatment depends on his/her motivation, which can change throughout the therapeutic intervention. As several studies found positive results for effects of MI24-26 and its use by health professionals is encouraged23,27 nurses may play an important role in patients' process of change. As nurses have a crucial role in clinical contexts, they can facilitate the process of ending risk behaviors and/or adopting positive health behaviors through some motivational techniques, namely with adolescents. A considerable number of systematic reviews about MI already exist pointing to some benefits of its use in the treatment of a broad range of behavioral problems and diseases.13,28,29 Some of the current reviews focus on examining the effectiveness of MI for adolescents with diverse health risks/problems 30-32. However, to date there are no reviews that present and assess the evidence for the use of nurse-led MI in adolescents. Therefore, we have little knowledge of what works for whom (which adolescent subpopulation) under what circumstances (in which setting, for what problem) in relation to motivational interviewing by nurses. There is a clear need for scoping or mapping the use of MI by nurses with adolescents to identify evidence gaps and to inform opportunities for future development in nursing practice. On the other hand, information regarding nurse-led implemented and evaluated interventions, techniques and/or strategies used, contexts of application and adolescents subpopulation groups is dispersed in the literature33-36 which impedes the formulation of precise questions about the effectiveness of those interventions conducted by nurses and therefore the realization of a systematic review. In other words, it is known that different kind of motivational interventions have been implemented in different contexts by nurses, however does not exist a map about all the motivational techniques and/or strategies used. Furthermore the literature does not clarify which is the role of nurses at cross professional motivational intervention implemented programs and finally the outcomes and evaluation of interventions are unclear. Thus, the practical implication of this mapping will be clarifying all these aspects. Without this clarification is not possible to proceed to the realization of a systematic review about the effectiveness of the use of motivational interviews by nurses to promote health behaviors in adolescents, in a particular context and/or health risk behavior; or regarding the effectiveness of certain technique and/or strategy of MI. Consequently, there are important questions about the nature of the evidence in this area that need to be answered before formulating a precise question of effectiveness. This scoping review aims to respond to these questions. An initial search of the JBI Database of Systematic Reviews & Implementation Reports, Cochrane Database of Systematic Reviews, , Database of promoting health effectiveness reviews (DoPHER), The Campbell Library, Medline and CINAHL, has revealed that currently there is no Scoping Review (published or in progress) on the subject. In this context, this scoping review will examine and map the published and unpublished research around the use of MI by nurses implemented and evaluated to promote health behaviors in adolescents; to establish its current extent, range and nature and identify its feasibility, outcomes and gaps in the evidence defining research priorities in this field. This scoping review will be informed by the JBI methodology37 that suggests a five stage methodological framework for conducting scoping reviews which includes: identifying the research question, searching for relevant studies, selecting studies, charting data, collating, summarizing and reporting the results.

Prática de ensino supervisionada em educação pré-escolar e ensino do 1º ciclo do ensino básico: conceções alternativas em ciência

O presente relatório tem como finalidade apresentar o trabalho realizado no âmbito das unidades curriculares da Prática de Ensino Supervisionada em Pré-Escolar e em 1.º Ciclo do Ensino Básico, inseridas no Mestrado em Educação Pré-Escolar e Ensino do 1.º Ciclo do Ensino Básico na Universidade de Évora, com enfoque na temática: “Conceções Alternativas em Ciência”. A PES decorreu em dois contextos distintos, sendo primeiramente realizada numa sala de Educação Pré-Escolar na Escola Básica Galopim de Carvalho e por fim, numa turma de 2.º ano do 1.º Ciclo do Ensino Básico, na Escola Básica dos Canaviais. Ambas pertencem ao Agrupamento n.º 4 de Évora. A investigação realizada consistiu em identificar e valorizar as conceções alternativas das crianças/alunos; promover a construção de conhecimentos a partir das conceções alternativas; usar estratégias de mudança concetual que visassem criar um confronto entre as conceções alternativas e os conceitos científicos. Esta investigação permitiu a confirmação de que é importante, no ensino das ciências, serem promovidas atividades de mudança concetual, apesar de alguns investigadores afirmarem que estas conceções alternativas podem ser um obstáculo na aprendizagem de novos conhecimentos; ABSTRACT: This report aims to present the work done within the course units of “Supervised Teaching Practice in Pre-School and 1st Basic Education” in Masters in “Pre-School Education and Training of 1st Basic Education” at the University of Évora, focusing on the theme “Alternative conceptions in Science”. The PES held in two different contexts: first performed in a pre-school education classroom at “Escola Básica Galopim de Carvalho” and second in a second year class of 1st Basic Education at “Escola Básica dos Canaviais”. Both schools belong to “Agrupamento n. º 4 of Évora”. The research was carried out to identify and value the alternative conceptions of children/students; promote the construction of knowledge from alternative conceptions; use conceptual change strategies which aimed to create a confrontation between alternative conceptions and scientific concepts. This investigation has confirmed that it is important in science education to promote conceptual change activities, as some researchers claim that these alternative conceptions can be an obstacle in learning/developing new skills.

Geological realism in hydrogeological and geophysical inverse modeling: A review

Scientific curiosity, exploration of georesources and environmental concerns are pushing the geoscientific research community toward subsurface investigations of ever-increasing complexity. This review explores various approaches to formulate and solve inverse problems in ways that effectively integrate geological concepts with geophysical and hydrogeological data. Modern geostatistical simulation algorithms can produce multiple subsurface realizations that are in agreement with conceptual geological models and statistical rock physics can be used to map these realizations into physical properties that are sensed by the geophysical or hydrogeological data. The inverse problem consists of finding one or an ensemble of such subsurface realizations that are in agreement with the data. The most general inversion frameworks are presently often computationally intractable when applied to large-scale problems and it is necessary to better understand the implications of simplifying (1) the conceptual geological model (e.g., using model compression); (2) the physical forward problem (e.g., using proxy models); and (3) the algorithm used to solve the inverse problem (e.g., Markov chain Monte Carlo or local optimization methods) to reach practical and robust solutions given today's computer resources and knowledge. We also highlight the need to not only use geophysical and hydrogeological data for parameter estimation purposes, but also to use them to falsify or corroborate alternative geological scenarios.

Efectos de una intervención educativa en los conocimientos y prácticas de los estilos de vida saludables para la prevención del cáncer de seno en estudiantes mujeres de un colegio público de la localidad de Ciudad Bolívar en Bogotá, Colombia

Objetivo: Evaluar los efectos de una intervención educativa en la práctica del autoexamen de seno, los conocimientos y práctica de los estilos de vida saludables para la prevención del cáncer de seno en estudiantes mujeres de un colegio público de la localidad de Ciudad Bolívar en Bogotá, Colombia. Materiales y métodos: Estudio de intervención, antes y después, no controlado en un periodo de seis meses con la participación de mujeres jóvenes estudiantes entre 10 y 20 años de edad. Se contemplaron cinco momentos metodológicos ejecutados en los meses de febrero en el cual se realizó la aplicación del cuestionario auto-diligenciado; de marzo en el cual las estudiantes recibieron una sesión educativa de 90 minutos y una de 60 minutos, soportadas con material audiovisual y folletos informativos. Se realizó el seguimiento prospectivo para la toma de datos en uno, tres y seis meses post-intervención. Conclusiones: 155 estudiantes fueron encuestadas. La prevalencia de práctica del autoexamen de seno fue de 78,1% (n=121). Se evidenció un cambio significativo en el conocimiento de la técnica y la práctica del autoexamen de seno, así como aumentos significativos en los conocimientos de los principales factores de riesgo para el cáncer de mama (p<,0001). En cuanto a los estilos de vida, las estudiantes mejoraron de manera significativa la práctica regular de actividad física con más de 150 minutos semanales a los 6 meses post-intervención. Conclusión: Una intervención educativa puede mejorar los conocimientos acerca de los factores de riesgo para cáncer de mama, la práctica del autoexamen de seno y los estilos de vida en mujeres jóvenes estudiantes de una localidad de bajo nivel socio-económico en Bogotá, Colombia. Estudios experimentales de alta calidad son requeridos.

Efectos de una intervención educativa en la promoción de la actividad física, los conocimientos y comportamientos saludables para la prevención del cáncer colorrectal en jóvenes de una institución educativa secundaria en Bogotá Colombia

El cáncer colorrectal es un serio problema de salud pública a nivel mundial. Evidencias epidemiológicas han sugerido que al menos el 50% de la enfermedad puede ser prevenida mediante un estilo de vida saludable. Las intervenciones educativas surgen como una herramienta clave de movilización social para la prevención y han sido sugeridas desde las autoridades nacionales para el control del cáncer en el país.

Efectos de una intervención educativa en los conocimientos y comportamientos relacionados con la fotoprotección durante la práctica de la actividad física en los estudiantes de un colegio público de Bogotá D.C., Colombia

Introducción: La incidencia del cáncer de piel melanoma y no melanoma es un problema de salud pública a nivel mundial. El incremento en la incidencia del cáncer de piel en los últimos años se debe a múltiples factores como: cambios en los estilos de vida, el envejecimiento de la población, cambios ambientales, el desconocimiento a la exposición a la radiación ultravioleta (RUV) durante la práctica de actividad física sin elementos de fotoprotección, siendo éste último reconocido como el principal factor de riesgo. Objetivo: Evaluar los efectos de una intervención educativa en los conocimientos y comportamientos relacionados con la fotoprotección durante la práctica de la actividad física en estudiantes de un colegio público de Bogotá D.C., Colombia. Métodos: Estudio de intervención, antes y después, no controlado en 281 estudiantes de los grados noveno, décimo y once de estratos 1-3 de un colegio público de Bogotá, con seguimiento a 1, 3 y 6 meses post-intervención. Se evaluaron los conocimientos y los hábitos de fotoprotección mediante un cuestionario Cancer Awareness Measure (CAM) y el modelo Transteórico de cambio comportamental de Prochaska y Di Clemente. El estudio se realizó durante el primer semestre de 2015 con 4 sesiones educativas de 60 minutos apoyadas con material audiovisual y pedagógico, acorde a la Guía para la Comunicación Educativa en el marco el control del cáncer publicada por el Instituto Nacional de Cancerología. Resultados: Del grupo de estudiantes que participaron del estudio, el 52,3% eran hombres, el promedio de edad fue de 15,46 ± 1,2 años. El tipo de piel predominante fue la trigueña con 65,8%. La intervención educativa produjo cambios significativos en los conocimientos de foto protección, finalizado el seguimiento al sexto mes. En cuanto a la prevención los estudiantes refirieron tener conocimiento de cómo examinar su piel en el momento basal (12,5% n=35), presentándose un aumento significativo de 62,6% (n=211) al sexto mes (p<0,05). Conclusión: El estudio demostró la efectividad de la intervención educativa, evidenciando cambios significativos en los conocimientos en fotoprotección y comportamientos preventivos del cáncer de piel durante la práctica de la actividad física en estudiantes de un colegio público de Bogotá D.C., Colombia.

Efectos de una intervención educativa en la promoción de la actividad física, otros comportamientos saludables y los conocimientos para la prevención del cáncer de pulmón en jóvenes del colegio La Merced en Bogotá D.C., Colombia

Introducción: El cáncer de pulmón es el tipo de cáncer más mortal a nivel mundial, al cual se atribuyen una de cada cinco muertes anualmente. El objetivo de este estudio fue determinar los efectos de una intervención educativa en la promoción de la actividad física, otros comportamientos saludables y los conocimientos para la prevención del cáncer de pulmón en jóvenes estudiantes de una institución educativa pública en Bogotá, Colombia. Métodos: Estudio experimental no controlado en 243 estudiantes de sexo femenino (Edad 14±1,5 años). La intervención educativa se desarrolló en tres momentos: una sesión educativa con una duración de 60 minutos acorde a la Guía para la Comunicación Educativa en el Marco del Control del Cáncer, en Colombia. Segundo, se enviaron tres correos electrónicos con información acerca del cáncer pulmonar; finalmente se desarrollaron actividades grupales. Para la toma de datos se utilizaron el cuestionario Cáncer Awareness Measure (CAM) y el Sistema de Vigilancia de Factores de Riesgo del Comportamiento (BRFSS). La evaluación se realizó en un período de seguimiento a 1, 3 y 6 meses post-intervención. Resultados: La intervención educativa incrementó significativamente los conocimientos de las jóvenes sobre los signos de alarma del cáncer pulmonar y los principales factores de riesgo modificables, tales como el consumo de cigarrillo, la exposición al humo del mismo y el sedentarismo, al sexto mes post-intervención. Las mejoras en el cambio comportamental no lograron significancia estadística. Conclusiones: Una intervención educativa mejora los conocimientos acerca de la detección temprana y la prevención del cáncer de pulmón, así como los comportamientos saludables en jóvenes estudiantes en Bogotá, Colombia. Se requiere de estudios controlados aleatorizados.

Etapas de cambio comportamental frente al consumo de drogas ilegales, tabaco y alcohol en escolares de 9 a 17 años de Bogotá – Colombia

Objetivo: El propósito del estudio fue describir estadísticamente las etapas de cambio comportamental frente al consumo de sustancias psicoactivas –SPA– (alcohol, tabaco y drogas ilegales) en escolares entre 9 y 17 años de Bogotá- Colombia, pertenecientes al estudio FUPRECOL. Método: Se trata de un estudio descriptivo y transversal en 6.965 niños y adolescentes entre 9 y 17 años, pertenecientes a 24 instituciones educativas oficiales de Bogotá - Colombia. La medición de los procesos de cambio propuestos por el Modelo Transteórico (MTT), aplicados al consumo de drogas, tabaco y alcohol se aplicaron de manera auto-diligenciada mediante un cuestionario estructurado. Resultados: De la muestra evaluada, el 58,4% fueron mujeres con un promedio de edad 12,74 ± 2.38 años. En la población en general, frente al consumo de drogas, el 6% de los escolares se encontraban en etapa de pre-contemplación, 44 % en contemplación; 30% en preparación/acción, 20% en mantenimiento. Con relación al consumo de alcohol, el 5% de los niños y adolescentes se encontraban en etapa de pre-contemplación, 36 % en contemplación; 12% en preparación/acción, 46% en mantenimiento. Frente al tabaco, el 4% de los niños y adolescentes se encontraban en etapa de pre-contemplación, 33 % en contemplación; 12% en preparación/acción, 51% en mantenimiento. Conclusiones: En los escolares evaluados, un importante porcentaje se ubica en la etapa de mantenimiento frente a la intención de consumo de tabaco y alcohol. Frente al consumo de drogas ilegales los niños y adolescentes están en la etapa de contemplación. Se requieren esfuerzos mayores para fomentar programas preventivos que enseñen sobre el riesgo del abuso/dependencia de este tipo de sustancias psicoactiva sobre la salud; dándole prioridad en las agendas y políticas públicas dentro del ámbito escolar.