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Caracterização dos quimiorreceptores de O2 envolvidos no controle dos reflexos cardio-respiratórios de trairão, Hoplias lacerdae (Teleostei, Erythrinidae) em resposta à hipóxia ambiental
(Universidade Federal de São Carlos, 2008-01-24) Micheli, Mariana Andrade de; Rantin, Francisco Tadeu; https://lattes.cnpq.br/3546242299713690; https://lattes.cnpq.br/7871812883659034
The ability to sense and respond to oxygen availability in the environment is of extreme functional importance for fish. This is even more so in tropical freshwater habitats where environmental hypoxia can occur rapidly in space and time. Recent physiological studies on the cardio-respiratory response of tropical fishes have focused on hypoxia tolerant species. This aim of this study was to examine the neural control and function of the cardio-respiratory system in a fish that is adapted to living at high levels of oxygen. Trairão, Hoplias lacerdae was chosen because it is a member of the Erythrinidae family, in which most of species are hypoxia tolerant, including some where the O2 receptors has already been characterized. The study focused on investigation of the localization, distribution and orientation of chemoreceptors of O2 in trairão. Also how the cardio-respiratory parameters were modified by hypoxia. The fish were submitted to selective denervations of the branchial branches of the cranial nerves IX and X. These were, (1) only IX nerve sectioned at the 1st gill arch (IX; n = 9), (2) first gill arch both IX and branch of X sectioned (G1; n = 9), (3) all four gill arches both IX and X sectioned (G4; n = 8), (4) a control group (n = 8) and (5) a sham-operated group that underwent surgery but no nerves were sectioned (n = 4). A cannula was inserted into the ventral aorta to monitor changes in heart rate and blood pressure. Ventilation rate and amplitude was also monitored with a cannula through the roof of the buccal cavity. The fish were exposed to a gradual hypoxia from 140 to 10 mmHg. Either the internal and external surfaces of the gill were treated with NaCN to determine the receptors orientation. Results showed that the receptors related to the heart rate control and ventilation amplitude were distributed over all gill arches on both the internal and external surfaces, and the branches of the both nerves IX and X were involved in these responses. This pattern differs from that observed for the ventilation rat. The receptors involved in the control of this response are located internally to the first gill arch. Tairão also showed blood pressure control chemorecptors on the first gill arch, involved in a very efficient barostatic control. Extrabranchial O2 chemoreceptors were not identified in trairão. This differs from the hypoxia tolerant fish, where extrabranchial chemoreceptors are important to start the cardio-respiratory responses the most fast and accurate possible
Uma investigação sobre a prática pedagógica: refletindo sobre a investigação nas aulas de matemática
(Universidade Federal de São Carlos, 2008-01-24) Abreu, Maria das Graças dos Santos; Passos, Cármen Lúcia Brancaglion; https://lattes.cnpq.br/6276753402517432
This research, of qualitative approach, was done in State public schools and private ones of the city of Campinas SP. It is about a research of my own practice that seeks to comprehend the changes occurred in practice inside of an exploratoryinvestigative task accomplishment context during the Mathematics classes. These tasks are work proposals in which students explore an open situation, look for regularities, formulate problems, create conjectures, discuss and communicate written or orally their own conclusions. This study, that has a perspective towards to the researcher own professional practice, tries to analyze and comprehend how the professional process is performed in an environment of exploratory-investigative tasks and the interpretation of my own practice in a context of investigative classes. The investigation was guided by the question: What are the contributions that a work with exploratory-investigative tasks gives to the process of reflection of my own practice and to the transformation of some teaching and student knowledge? The required documentation to the study were constituted of: Written records of the students, gathered in different moments of my professional path; written records of the teacher-researcher, organized in a narrative form, that fulfill the purpose of a field diary; audio records of two work groups and of a socialization class of the results. The development of this work was divided in three parts: The first of them presents the methodology chosen for the development of the research, the data and a professional narrative of the teacher s professional background, since the period of an Elementary student, the Graduation, the first years of teaching and the come back to the University for the Master s Degree; The second part presents the theoretical references about teacher s development, teaching knowledge, teacher-researcher and teacher researcher of its own practice also presents an abstract that pursuits the differences and closeness between problem solving and the mathematical investigations; the third part presents the analyses of the gathered data and centered in three categories: (a) the guidance/interaction performed by the teacher; (b) student s acquired autonomy; and (c) the Mathematics class as an epistemological place of knowledge production. In the final part of this research we find the reflections produced by the teacher due to the narrative productions, from the performed studies and collected material analyzes. The results point to the importance of the teacher s research about its own practice that in this movement of investigation of his/her part inside the classroom, finds him/herself investigating his/her own world, searching him/herself, discovering him/herself, putting him/herself together with the students in order to reflect and review the already acquired knowledge, converting them into new knowledge and producing new knowledge to yourself and to other Mathematics teachers. It also presents the student s development regarding the investigation tasks, pointing out that this model of work offer opportunities for participating with an individual and group collection; autonomy to the creation and development of Mathematics