Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Diffusion of exchangeable water in cortical bone studied by nuclear magnetic resonance.

The rate-limiting step in the delivery of nutrients to osteocytes and the removal of cellular waste products is likely diffusion. The transport of osteoid water across the mineralized matrix of bone was studied by proton nuclear magnetic resonance spectroscopy and imaging by measuring the diffusion fluxes of tissue water in cortical bone specimens from the midshaft of rabbit tibiae immersed in deuterium oxide. From the diffusion coefficient (D(a) = (7.8 +/- 1.5) x 10(-7) cm(2)/s) measured at 40 degrees C (close to physiological temperature), it can be inferred that diffusive transport of small molecules from the bone vascular system to the osteocytes occurs within minutes. The activation energy for water diffusion, calculated from D(a) measured at four different temperatures, suggests that the interactions between water molecules and matrix pores present significant energy barriers to diffusion. The spatially resolved profile of D(a) perpendicular to the cortical surface of the tibia, obtained using a finite difference model, indicates that diffusion rates are higher close to the endosteal and periosteal surfaces, decreasing toward the center of the cortex. Finally, the data reveal a water component (approximately 30%) diffusing four orders of magnitude more slowly, which is ascribed to water tightly bound to the organic matrix and mineral phase

Three‐dimensional nuclear magnetic resonance microimaging of trabecular bone

The conventional approach to measuring structural parameters in trabecular bone rests on stereology from optical images, derived from sections of embedded bone. In order to provide data that are statistically representative of a sufficiently large volume, multiple sections need to be analyzed in each of the three orthogonal planes. In this work, an alternative technique is presented which is based on three‐dimensional (3D) volumetric proton nuclear magnetic resonance (NMR) microimaging. The method presented provides images from 9 × 9 × 4 mm3 volumes of defatted bone specimens in 15–20 minutes scan time at isotropic resolution corresponding to (78 μm)3 voxel size. Surface‐rendered images of bovine and human trabecular bone are shown and an algorithm was developed and implemented for determining the orientation and magnitude of the principal axes of the mean intercept length tensor. Copyright © 1995 ASBM

The Ketogenic Diet Does Not Affect Growth of Hedgehog Pathway Medulloblastoma in Mice.

The altered metabolism of cancer cells has long been viewed as a potential target for therapeutic intervention. In particular, brain tumors often display heightened glycolysis, even in the presence of oxygen. A subset of medulloblastoma, the most prevalent malignant brain tumor in children, arises as a consequence of activating mutations in the Hedgehog (HH) pathway, which has been shown to promote aerobic glycolysis. Therefore, we hypothesized that a low carbohydrate, high fat ketogenic diet would suppress tumor growth in a genetically engineered mouse model of medulloblastoma. However, we found that the ketogenic diet did not slow the growth of spontaneous tumors or allograft flank tumors, and it did not exhibit synergy with a small molecule inhibitor of Smoothened. Serum insulin was significantly reduced in mice fed the ketogenic diet, but no alteration in PI3 kinase activity was observed. These findings indicate that while the ketogenic diet may be effective in inhibiting growth of other tumor types, it does not slow the growth of HH-medulloblastoma in mice

Potential role of nuclear magnetic resonance for the evaluation of trabecular bone quality

This paper discusses two novel applications of nuclear magnetic resonance (NMR) as an investigational tool for the assessment of cancellous bone microarchitecture. It further outlines extensions of the method for in vivo clinical evaluation of bone strength in patients with skeletal disorders such as osteoporosis. The first method relies on the hypothesis that the presence of two phases of different magnetic permeability, i.e., bone and bone marrow, causes a spatial nonuniformity of the magnetic field across the measurement volume. The resulting spread in resonance frequency shortens the decay time constant (T2*) of the time domain proton signal in bone marrow or its substitute (water). Increased trabecular spacing, such as it occurs in osteoporosis, reduces the spatial field inhomogeneity and thus prolongs T2*, which has been shown both in vitro and in vivo. Subjects with osteoporosis, characterized by either low bone mineral density and/or spine compression fractures, have T2* values that are significantly prolonged. The second method focuses on a direct measurement of micromorphometric parameters of cancellous bone, using the principles of proton NMR microscopy in conjunction with computer processing of the resulting digital images. Image contrast between the trabeculae and the intertrabecular space is based on the marrow protons providing a signal, as opposed to bone, which appears with background intensity. Once tissues have been classified (into bone and marrow), for example, by means of a histogram-based segmentation algorithm, bone area fraction, mean trabecular plate density (MTPD), and mean trabecular plate thickness (MTPT) can be computed without the need for further operator intervention. The most critical parameter for successful implementation is image slice thickness which determines the extent of partial volume blurring. At 400 MHz spectrometer frequency (9.4 T field strength), images of appropriate resolution can be obtained from a 1 cm3 specimen of vertebral cancellous bone in 1 hour or less. It is shown that for relatively isotropic cancellous bone such as the one found in the vertebrae, a slice thickness on the order of 200 μm is adequate, with an inplane resolution on the order of 50 × 50 μm2 As an illustration of the technique, the relationship among the different stereologic parameters in cadaver specimens of human lumbar vertebrae is reported, showing a strong association between the area fraction and both MTPD and MTPT. The chief benefit of the new technique is its nondestructive nature and its ability to provide histomorphometric images from multiple physical locations and in multiple planes, which is desirable because of the large spatial variations in the morphologic parameters within the bone. Finally, the technique is demonstrated to be potentially also noninvasive, as illustrated with images from the human finger, acquired on a modified 1.5 Tesla clinical magnetic resonance imaging system at a pixel size of 95 × 95 μm2 © 1993 Springer-Verlag New York Inc