A comunicação na sala de aula de matemática: um projecto colaborativo com três professoras do ensino básico

Tese de doutoramento em Educação (Didáctica da Matemática), apresentada à Universidade de Lisboa através da Faculdade de Ciências, 2007Esta investigação visa estudar a comunicação na sala de aula de matemática e, de forma particular, o papel do professor e as dificuldades que enfrenta. Porque o professor é a chave de todo o processo de mudança, propus a três professoras do ensino básico a realização de um projecto colaborativo de investigação sobre a prática. Este estudo encontra um suporte teórico em duas áreas distintas: a comunicação na sala de aula de matemática e a colaboração. Na primeira procuro caracterizar a comunicação na sala de aula de Matemática, prestando uma especial atenção aos diferentes padrões de interacção presentes, à construção de uma comunidade matemática e ao papel do professor. Na segunda área, para além da distinção entre diferentes tipos de colaboração, atribuo uma especial atenção à colaboração como oportunidade de investigação e à prática colaborativa com todas as dificuldades e tensões associadas.A metodologia adoptada neste estudo insere-se no paradigma interpretativo estruturando-se em três estudos de caso que correspondem a cada uma das professoras que compõem o projecto de investigação colaborativa. Os três estudos de caso basearam-se essencialmente na análise de aulas, nas reuniões de trabalho do projecto colaborativo, durante um ano lectivo e meio, e ainda nas duas entrevistas semi-estruturadas realizadas a cada professora, no início e no final do projecto.Com esta investigação foi possível identificar concepções e práticas das professoras relativamente à comunicação na sala de aula. Permitiu ainda encontrar factores que influenciam o modo como as professoras vêem aí o seu papel assim como as potencialidades da colaboração para proporcionar a evolução dessas práticas. O projecto de investigação colaborativa que sustentou este estudo, revelou-se importante como lugar de entreajuda, reflexão e investigação sobre a complexidade das práticas de comunicação. Posso ainda concluir que só a partir da tomada de consciência do que caracteriza a prática de comunicação de um professor, na diversidade da sua experiência pessoal e profissional, é que se torna possível identificar as dificuldades e encontrar formas de as superar.The aim of the research project presented is to study communication in the Mathematics classroom, with a particular emphasis on the teacher's role and its difficulties. As teachers play a keyrole in every educational change, my starting point was a proposal made to three elementarymathematics teachers for joining a collaborative research project on communicative practices.The theoretical framework for this research project develops two distinct areas: communicationin the mathematics classroom and collaboration. In the former I characterise the theme, with a specialfocus on the diversity of interaction patterns involved, the building of a mathematical community andthe teacher's role in the whole process. In the latter, besides drawing a distinction between differentcollaboration styles, I discuss collaboration as an opportunity for research, as well as collaborativepractices, their tensions and problems.From a methodological point of view this study follows the interpretative paradigm. It isstructured around three case-studies, one on each of the three teachers involved in the collaborativeresearch project. All of them are based on analysis of a number of class transcripts, minutes of theproject meetings for one year and a half, and two semi-structured interviews which took place, in eachcase, at the initial and final stage of the project.The research project made it possible to identify what teachers' conceptions and practices withrespect to communication in the classroom are, which elements influence how teachers regardthemselves there and the potentiality collaboration has for improving such practices. The collaborativeresearch project with the teachers became a relevant instance for confronting practices, researchingabout their complexity, innovation and self support. The study highlights that only by becoming aware ofwhat characterises teachers' communication practices, in the diversity and uniqueness of their ownpersonal and professional experience, it is possible to identify sources of difficulties and forms to get around them

Teachable Moments: oportunidades a não perder

Neste texto começamos por analisar um episódio ao nível das ações desencadeadas por uma professora e do conhecimento didático que as suporta. Depois, analisamos a forma como futuros professores de Matemática, a iniciarem o seu mestrado profissionalizante entendem o episódio, do ponto de vista matemático e do ponto de vista da gestão da aula. Finalmente, terminamos com algumas questões para a formação de professores que decorrem desta análise

Peritoneal and hepatic hydatid disease causing major bile duct destruction

Echinococcosis is endemic in Mediterranean regions and is found primarily in the liver. Biliary fistula is a common complication, but major biliary duct involvement is very rare, and occurs in 0.47% of patients with hepatic hydatid disease. Cyst rupture causing secondary peritoneal hydatidosis is a rare but serious complication. We report the case of a 27-year-old man with multiple peritoneal and hepatic hydatid cysts. The patient came to our attention with cholestatic jaundice. Imaging exams showed numerous peritoneal cysts and massive hydatid disease of the liver, which involved the hepatic confluence, with destruction of the right hepatic duct and fistula formation to the left hepatic duct. The patient was treated with pre-operative albendazole therapy and radical surgery, which consisted of resection of all peritoneal cysts and extended right hepatectomy with biliary reconstruction. No recurrence was seen on CT investigations on the 12th month following surgery. Radical surgical approach remains the treatment of choice

Estuarine production of resident and nursery fish species: Conditioning by drought events?

The production of resident (Pomatoschistus minutus and Pomatoschistus microps) and marine juvenile fish species using the Mondego estuary (central Portugal) as nursery grounds (Dicentrarchus labrax, Platichthys flesus, Solea solea), was assessed in order to: (1) understand the potential of the estuary for fish production; (2) know the production of nursery fish species likely to be exported to the coastal stocks; and (3) how anthropogenic and natural stress could influence the estimated production. Sampling occurred from June 2003 to May 2006 and together the 5 species in study comprised around 70% of the whole fish community numbers and biomass. Increasing drought conditions were observed, starting with a normal hydrological year in 2003 until attaining a severe drought in 2005, which resulted in low river discharges (1/3 of the mean river discharges in 2003). Additionally, high water temperatures were observed in 2003 and 2005 (24 and 26 °C, night temperatures). The secondary production was estimated using the increment summation method, after recognition of the cohorts. Production was in general lower in the Mondego estuary when compared to other systems, which was associated to the estuary's small area (only 3.4 km2, less than 1/4 of area compared to other studied systems). Dicentrarchus labrax was among the most productive species. Production decreased in the drought year for all species, especially evident for D. labrax, P. minutus and P. flesus. No direct effects could be attributable to the salinity and temperature variations and to the low freshwater discharges (resulting from the drought and high temperatures), yet these were pointed as probable major reasons for the decreased production. A significant reduction (15-45% reduction in the estuarine production) was also concluded for the potential production to be exported for coastal areas by the nursery species in the drought conditions.http://www.sciencedirect.com/science/article/B6WDV-4R9GGXS-2/1/663d5981f8928a75fea6999bf328f16

Abrupt field-induced transition triggered by magnetocaloric effect in phase-separated manganites

The occurrence at low temperatures of an ultrasharp field-induced transition in phase separated manganites is analyzed. Experimental results show that magnetization and specific heat step-like transitions below 5 K are correlated with an abrupt change of the sample temperature, which happens at a certain critical field. This temperature rise, a magnetocaloric effect, is interpreted as produced by the released energy at the transition point, and is the key to understand the existence of the abrupt field-induced transition. A qualitative analysis of the results suggests the existence of a critical growing rate of the ferromagnetic phase, beyond which an avalanche effect is triggered.Comment: 6 pages, 4 figures included. Acepted for publication in Phys. Rev.

Unconventional Metallic Magnetism in LaCrSb{3}

Neutron-diffraction measurements in LaCrSb{3} show a coexistence of ferromagnetic and antiferromagnetic sublattices below Tc=126 K, with ordered moments of 1.65(4) and 0.49(4) Bohr magnetons per formula unit, respectively (T=10 K), and a spin reorientation transition at ~95 K. No clear peak or step was observed in the specific heat at Tc. Coexisting localized and itinerant spins are suggested.Comment: PRL, in pres

Assessing estuarine environmental quality using fish-based indices: Performance evaluation under climatic instability

http://www.sciencedirect.com/science/article/B6V6N-4TFDY7X-2/2/c9f9bbc565621cbb798d6d663e74a8f