La Maîtrise Intuitive des Relations entre Masse,Volume et Masse Volumique Chez des Elèves du Premier Cycle

Three experiments have been devoted to the application of the methodology developped by Anderson, N. H. (1981, 1982) in the framework of the Information Integration Theory to the problem of the mastery by children (14 old) of the relations between the notions of mass, volume and volumic mass. It appears that, having to judge of the mass values of diverses objects from given values of volume and volumic mass, a majority of pupils are able to take account of the positive link between the mass on the one part and the volume and the volumic mass on the other part but apply an additive type integration rule. However, a minority of pupils are able to apply a normatively correct multiplicative rule. Concerning the judgements of volume values from given mass and volumic mass values, and the judgements of volumic mass values from given mass and volume values, a majority of pupils apply a soustractive integration rule. In these two cases however the integration patterns are extremely variegated. The relation between the algebraic level of analysis of the judgement data and an information processing level of analysis of the same data is discussed. The use by teachers of the paradigm presented in the study with the aim of improving upon the current evaluation methods is proposed.     

Introduction to this Special Issue

In 2001, for the first time in the history of the International Association for Counselling, International Conference was held in a developing Asian country–India, with the theme Families in Transition–Counselling in Transition–Meeting the Challenges Ahead. This special issue contains some of the presentations made by Indian participants during this conference which best reflect the challenges and diversities of counseling efforts with families in India. The first article was specially written for this issue in order to give an international relationship of this journal an in depth contextual understanding of Indian families in transition and the challenges they pose to the contemporary Indian counselor. Two articles are reflected to counseling families affected by socio-politial and economic changes. Five authors have written on counseling related to physical and mental disability/addiction and last two articles are reflected to authors experiences as family counselors.     

Conditioned inhibition in feature negative discrimination learning with pigeons

Discrimination performance was investigated with pigeons using feature negative (FN) discrimination procedures which differed in the temporal arrangement of the stimuli on S? trials. In both procedures, a single common element was presented on reinforced (S+) trials. In thesimultaneous FN procedure, a distinguishing element was presented simultaneously with the common element of S? trials. In thesequential FN procedure, the distinguishing element preceded onset of the common element on S? trials. In two experiments, the sequential FN procedure yielded better discrimination performance. In Experiment 1, a summation test designed to separate learning and performance variables indicated that sequential FN subjects had learned the negative relationship between the distinguishing element and reinforcement while simultaneous FN subjects had not. In Experiment 2, summation and acquisition tests indicated that the distinguishing element developed inhibitory properties in the sequential FN procedure but not in the simultaneous FN procedure.     

Kinetics study on biomass pyrolysis for fuel gas production

Kinetic knowledge is of great importance in achieving good control of the pyrolysis and gasification process and optimising system design. An overall kinetic pyrolysis scheme is therefore addressed here. The kinetic modelling incorporates the following basic steps: the degradation of the virgin biomass materials into primary products (tar, gas and semi-char), the decomposition of primary tar into secondary products and the continuous interaction between primary gas and char. The last step is disregarded completely by models in the literature. Analysis and comparison of predicted results from different kinetic schemes and experimental data on our fixed bed pyrolyser yielded very positive evidence to support our kinetic scheme. Project (No. 2001CB409600) Supported by the National Key Basic Research Program (973) of China     

普通话二字组词语的动态声调

普通话二字组词语不同的声调组合方式 ,使前后位声调产生不同的动态变化形式。前位声调的动态变化明显表现在上声调变为低降调和中升调上 ;后位声调的动态变化则表现在调值的明显改变上。后位声调的动态变化更为普遍 ,应该引起足够的重视     

Constructing a Joint Story-Writing Space: The Dynamics of Young Children's Collaboration at Computers

This study explored kindergartners' and first graders' collaborative processes to understand the nature of peer collaboration and the learning opportunities afforded by peer discourse. Data were drawn from 6 dyads who participated in a computer writing project for 2 school semesters. Children's videotaped interactions were analyzed with the focus on understanding how children's collaborative roles and patterns changed over time. Examination of video data and children's computer products revealed that (a) children's interaction patterns changed from a more independent style toward a more integrative style, as shown in their distribution of control over mouse and keyboard and in the written outcomes of their collaboration; (b) a shift in role patterns emerged across repeated instances of peer collaboration so that children began alternating the roles of leader and observer, and less competent children began carrying out more important tasks; and (c) the computer served as an object of reference for children to sustain their interaction and stay on task.