Numerical modeling of DNA-chip hybridization with chaotic advection

We present numerical simulations of DNA-chip hybridization, both in the “static” and “dynamical” cases. In the static case, transport of free targets is limited by molecular diffusion; in the dynamical case, an efficient mixing is achieved by chaotic advection, with a periodic protocol using pumps in a rectangular chamber. This protocol has been shown to achieve rapid and homogeneous mixing. We suppose in our model that all free targets are identical; the chip has different spots on which the probes are fixed, also all identical, and complementary to the targets. The reaction model is an infinite sink potential of width d_h, i.e., a target is captured as soon as it comes close enough to a probe, at a distance lower than d_h. Our results prove that mixing with chaotic advection enables much more rapid hybridization than the static case. We show and explain why the potential width d_h does not play an important role in the final results, and we discuss the role of molecular diffusion. We also recover realistic reaction rates in the static case.     

Interpersonal conflict resolution strategies in children: A father-child co-construction

The interpersonal conflict gives an opportunity to learn living together and to accept differences. We consider the interpersonal conflict resolution strategies as an indicator of the socialization and as such of the autonomisation and social integration. If, at the earliest age, the child has the advantage of a differentiated and early paternal involvement, he would use a larger variety of adjustment mechanisms when he will be in conflitual situations. Indeed, the father facilitates and stimulates the subjectivation process which integrates the appearing premises of self-consciousness, around 3–4 year old, in the conducts of initiative and self affirmation; the father introduces and consolidates the process which integrates the opening to wider interpersonal relations, which notably appears in collaboration conducts and more especially resolution interpersonal conflict.     

小学数学教科书中的比及其教学

在现行小学数学教科书,都把两个数的比定义为两个数相除,这样的定义不仅削弱了比的现实功能,而且无法让学生感悟比的数学本质.论证了比的本质是两个数量倍数关系的表达与度量,还论证了比与除法、分数、比例的差异.并且,对相关内容的教学提出了建议.     

Strategy development in children with mathematical disabilities: insights from the choice/no-choice method and the chronological-age/ ability-level-match design

This study investigated the strategy characteristics and development of children with mathematical disabilities (MD) in the domain of simple addition and subtraction, in terms of Lemaire and Siegler's model of strategic change, using the choice/no-choice method and the combined chronological-age (CA)/ability-level (AL)-match design. Four groups of children, matched on either CA or mathematical AL, solved a series of 36 problems with the bridge over 10 in four conditions. In the choice condition, children could choose between retrieval, decomposition to 10, and counting on to solve each problem. In the retrieval, decomposition, and counting conditions, they had to answer the same 36 problems using retrieval, decomposition to 10, and counting on, respectively. The results revealed clear differences in the frequency, efficiency, and adaptiveness with which the CA-matched children applied the available strategies. In contrast, we observed no differences in strategy frequency, efficiency, and adaptiveness between the AL-matched children. These results support the hypothesis that the strategy development of children with MD is marked by a delay rather than a specific deficit. Moreover, this study further documents the value of the methodology used to study children's strategy use and development in the domain of simple arithmetic.     

Neo-liberal influences in a ‘conservative’ regime: the role of institutions,family strategies,and market devices in transition to higher education in France

ABSTRACT

This article focuses on the interplay between institutional arrangements, family strategies, and market devices in the transition to higher education (HE) in France with a view to documenting both persistent features of the French ‘conservative’ educational regime and recent changes, in particular those related to neo-liberal influences. Using a theoretical model inspired by research on welfare regimes and integrating key elements of the sociology of networks, institutions, and markets, as well as data from a comprehensive qualitative study, the article focuses on three main topics: the impact of both institutional stratification and family choices on segregation and channelling into HE; the framing of students’ choices generated by impersonal policy instruments and personal human guidance; the role of private providers and agencies, as well as the devices they use to influence students’ transition to HE. The conclusion emphasises the impact of these different processes on the perpetuation of educational inequalities.     

Students’ transition from elementary to high school and changes of the relationship between motivation and academic performance

336 students, 186 girls and 150 boys were met at the end of the school year, both at grade six and at Secondary one, in order to examine the impact of the transition from elementary to secondary school on various motivational variables. Analyses showed changes in self-efficacy beliefs and learning goals, whatever students’ level of achievement and gender. However, self-efficacy beliefs appeared as the most powerful predictor of academic performance at both school levels. In addition, the pattern of relations between academic performance and the variables examined was relatively similar at both times of measurement. The discussion focuses on changes in self-efficacy beliefs and learning goals and on their relations to academic performance.     

Curricula and curricular analysis: Some pointers for a debate

This introduction to our guest-edited issue provides a framework for reflecting on curricula, based on the four still fundamental questions raised by Tyler (Basic principles of curriculum and instruction. University of Chicago Press, Chicago, 1949) about effective ways to organize educational experiences that can meet the school’s educational purpose. The authors begin by decoding the Franco-European and Anglo-Saxon/North American approaches to the concept of curriculum, and seek points where the two are complementary. Using Tyler’s four questions, they then clarify the concept in a conceptual outline, organize it into a rational model, and seek a reference framework that can offer pointers for a debate on curriculum. They then show that, because a curriculum necessarily originates in a specific society, some of that society’s irrationality affects the nature of the curriculum. Thus, any curriculum experiences a tension between the rationality of the models that define it in theoretical terms and the irrationality of its surrounding society—which has the power to regulate it. Therefore, tools for curriculum analysis must consider all these dimensions, contradictions, and tensions to achieve a truly systemic perspective. While a system model is important for evaluation, it is also important to understand the less rational aspects and to place them in dialogue with their models. In this respect, providing pointers for the debate on curriculum remains a perilous exercise. Finally, the authors reflect on a systemic and holistic approach to the curriculum, and suggest pointers for contemporary reflection on curriculum.     

A developmental approach to the risk of a first recurrence in child protective services

The objective of this study is to estimate the risk of a first recurrence over a five-year period following initial child protective services (CPS) intervention and identify the characteristics associated with the risk of recurrence for three different age groups. Recurrence is defined as the first substantiated report within the observation period after initial services have ended. The study involved a cohort of 25,897 Quebec children who received postinvestigation services for the first time and whose cases were closed between 2005 and 2009. Survival analysis was used to estimate the five-year risk of recurrence and Cox regression to model the risk of recurrence for three age groups. The covariates introduced into the regression analyses were characteristics of the child and initial services. The risk of recurrence in the five years following termination of initial CPS services was 36% for the entire cohort and varied depending on the child's age at the time of case closure. Children aged 6–11 when their cases were closed had the highest risk of recurrence. Although Aboriginal descent and prior CPS investigations have a consistent effect on the risk of recurrence in all three age groups, the effects of other covariates, such as out-of-home placement and court involvement, vary or are even reversed, depending on the child's age. These findings highlight the need to adopt a differential approach that takes into account the child's age, both in the provision of protective services and in research involving the population receiving such services.     

Thinking for speaking: the expression of motion events by Russian and Chinese learners of Catalan as a second language / Pensar para hablar: la expresión de eventos de movimiento en hablantes nativos de ruso y mandarín que aprenden catalán como una segunda lengua

Abstract

In this study we provide evidence for the influence of L1 typological patterns in elicited narratives in Catalan by bilingual speakers of three different typological languages. The expression of the semantic components of Path and Manner of motion of Russian L1 speakers and Mandarin L1 speakers was compared to that of native Catalan speakers. Following the Thinking for Speaking framework, it was hypothesized that if the preferred semantic structure of L1 is transferred to the L2, then productions would be organized and structured differently according to the typological characteristics of L1. Results show different patterns of expression in L2 with regard to lexical choice and syntactic-semantic structure. We argue that the results provide empirical support for the Thinking for Speaking hypothesis.     

Rethinking access,success and student retention in Open and Distance Learning

The focus of this paper is access problems distance students encounter when required to use the Internet for their studies, and how such problems influence the students’ ability to gain access to higher education. Empirically, the paper is informed by a qualitative case study of a Master’s programme in public administration offered to a group of students in a relatively remote area of Indonesia. It shows how access problems certainly become a challenge for such students, not only because of the absence of technology but also because of social constraints related to the presence of technology. However, as there are often no proper alternatives, new technology may well be considered a step forwards for such students, even if the new technology to some extent creates serious problems.