2,998 research outputs found

### Cabri's role in the task of proving within the activity of building part of an axiomatic system

We want to show how we use the software Cabri, in a Geometry class for preservice mathematics teachers, in the process of building part of an axiomatic system of Euclidean Geometry. We will illustrate the type of tasks that engage students to discover the relationship between the steps of a geometric construction and the steps of a formal justification of the related geometric fact to understand the logical development of a proof; understand dependency relationships between properties; generate ideas that can be useful for a proof; produce conjectures that correspond to theorems of the system; and participate in the deductive organization of a set of statements obtained as solution to open-ended problems

### Una propuesta para abordar el teorema de PitÃ¡goras en clase

En este artÃ­culo se expone una propuesta de enseÃ±anza para presentar el teorema de PitÃ¡goras a alumnos de educaciÃ³n media. TambiÃ©n se refieren algunos detalles del anÃ¡lisis que fundamentÃ³ la propuesta. Esta incluye trabajo de los estudiantes en torno a la desigualdad triangular, a la relaciÃ³n pitagÃ³rica y a expresiones algebraicas

### Instrumented activity and semiotic mediation: two frames to describe the conjecture construction process as curricular organizer

We document part of the process through which conjectures produced by students, with the aid of the dynamic geometry software Cabri, when they solve proposed geometric problems, become a curriculum organizer in the classroom. We first focus on characterizing studentsâ€™ instrumented activity recurring to utilization schema (Rabardel, 1995, in Bartolini Bussi and Mariotti, 2008), and then describe the teacherâ€™s content management through which the ideas produced by the students become key elements of knowledge construction

### Analyzing the proving activity of a group of three students

We present an analysis and outline an evaluation of the proving activity of a group of three university level students when solving a geometrical problem whose solution required the formulation of a conjecture and its justification within a specific theoretical system. To carry out the analysis, we used the model presented by Boero, Douek, Morselli and Pedemonte (2010) that centers on the arguments and rational behavior. Our analysis indicates that the studentâ€˜s proving activity is close to the one we used as a reference

### Prefacio

Aunque los artÃ­culos que componen este libro provienen principalmen- te de nuestro mÃ¡s reciente trabajo investigativo, no son documentos de inves- tigaciÃ³n sino de divulgaciÃ³n. En ellos nos acercamos, mucho mÃ¡s de lo que es habitual para un profesor, a asuntos clave para la enseÃ±anza y el aprendizaje de la demostraciÃ³n, entendido este como participaciÃ³n en prÃ¡cticas propias de la comunidad del discurso matemÃ¡tico. El libro estÃ¡ dirigido principalmente a profesores de matemÃ¡ticas en ejercicio de su profesiÃ³n y a estudiantes de postgrado en el campo de la EducaciÃ³n MatemÃ¡tica

### Dynamic geometry, implication and abduction: a case study

In this paper we illustrate the role of dynamic geometry as an environment that propitiates the use of empirical explorations to favor learning to prove. This is possible thanks to abductive processes, related to the establishment of implications that university students of a plane geometry course carry out when, supported by a dynamic geometry program, they solve a problem in which they must discover a geometric fact, formulate a conjecture and prove it

### Use of dragging as organizer for conjecture validation

In this article, we report on a study centred on the teaching and learning of proof in which there is evidence that dragging becomes a source for significant student participation in the validation of conjectures. The findings highlight the teacherâ€™s use of dragging as an organizer of the activity, in cases when there are conjectures that students consider acceptable but for which they do not have the theoretical elements to validate them

### A genetic approach to improvements of Candida tropicalis as a biocatalyst

It is well documented in the literature that, in addition to carbon sources such as glucose, Candida species are able to utilise a wide variety of n-alkanes which are degraded via beta-oxidation. Prior to beta-oxidation a primary oxidation system acts on the end terminal methyl groups to generate carboxyl groups. The main industrial aim of the work was to optimise the bioconversion of pelargonate [CH3(CH2)7COOH] to azeleate [HOOC(CH2)7COOH], i.e. the primary oxidation steps, by blocking the beta-oxidation pathway in C. tropicalis. To this end, a library of Sau 3AI partially digested C. tropicalis NCYC997 genomic DNA in pBR322 was constructed from which it was hoped to isolate and disrupt the long-chain fatty acid acyl-CoA oxidase genes, POX4 and POX5, which catalyse the first step of beta-oxidation. The library was probed with oligonucleotides specific to POX4 and POX5, and a putative POX4 clone was isolated.ChemGen Corporatio

### The Dual Capacity Doctrine in Products Liability Cases in Pennsylvania

Worker\u27s compensation statutes limit recovery by employees, for injuries occurring in the course of employment, to the benefits of the statute. The dual capacity doctrine in products liability cases allows recovery against the employer, as a manufacturer of a defective product, beyond worker\u27s compensation recovery. This comment explores the possibility of acceptance of the dual capacity doctrine in light of the implications of a recent Pennsylvania Supreme Court decision

### Garments without guilt? : an exploration of corporate social responsibility within the context of the fashion supply chain : case study of Sri Lanka

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