Análisis de las Estrategias Metodológicas implementadas por el docente en el desarrollo del proceso de enseñanza- aprendizaje en la disciplina de Geografía e Historia de Nicaragua y su Didáctica en los alumnos/as de Primer año “B” del turno regular de Formación Inicial Docente en la Escuela Normal Central de Managua Alesio Blandón Juárez durante el I semestre del Curso Escolar 2016

El presente trabajo de investigación tiene como finalidad analizar la efectividad que tienen las Estrategias Metodológicas implementadas por el docente en el desarrollo del proceso de enseñanza- aprendizaje en la disciplina de Geografía de Nicaragua y su Didáctica en los alumnos/as de Primer año “B” del turno regular de Formación Inicial Docente en la Escuela Normal Central de Managua Alesio Blandón Juárez durante el I semestre del Curso Escolar 2016. Dicho trabajo de investigación tiene un enfoque naturista o cualitativo, es una vía de transformación social, a través de la cual el ser humano descubre la realidad que le rodea, determina los medios y procedimientos para actuar sobre ella y transformarla de acuerdo a una intensión social. Los procesos de investigación cualitativa, tienen como finalidad primordial la generación y construcción de conocimientos que contribuyen al desarrollo social y personal de cada uno de los miembros de una comunidad. La fase de recolección de los datos de la investigación desarrollada, se realizó de dos formas: una información que se recogió mediante la observación directa del comportamiento de los informantes claves y una información que se obtuvo mediante la interrogación de algunos informantes claves. Para ello, primeramente el investigador realizo una inmersión en el campo de trabajo, con el propósito de identificar los lugares adecuados para recoger y producir la información necesaria y requerid

Correlation Between Metabolite Peak Area Ratios on the Influence of Poor Shimming by H MR Spectroscopy

Using 1 H magnetic resonance spectroscopy (MRS), we quantitatively evaluated correlation representing linear relationship between the metabolite peak area ratios associated with poor shimming conditions. The inadequate shimming due to linear shim offsets directly affected overall MR spectral quality as well as peak area for each metabolite. Three major peaks such as N-acetylaspartate (NAA), creatine (Cr), choline (Cho) were used as a reference for data analysis. Despite considerable variations of metabolite peak area, a significant correlation between the metabolite peak area ratios relative to Cr was established while the correlation between the peak area ratios relative to Cho and NAA was not. The present study suggested that metabolite peak area ratios based on the metabolite of Cr could be an acceptable quantification method even under the poor shimming in clinical MRS examinatio

Feasibility of Proton Chemical Shift Imaging with a Stereotactic Headframe

To prove feasibility of proton chemical shift imaging (1H CSI) during stereotactic procedure, authors performed 1H CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, evaluated the pathologic results. The 1H CSI directed stereotactic biopsy was performed in four patients. 1H CSI and conventional Gd-enhancement stereotactic MRI were performed simultaneously after the fitting of a stereotactic headframe. Focal areas of increased phosphocholine(Cho)/phosphocreatine(Cr) and Lactate/Cr ratios were selected as target sites in the stereotactic MR images. 1H CSI is possible with the stereotactic headframe in place. Pathologic samples taken from areas of increased Cho/Cr ratios and decreased NAA/Cr ratios provided information upon increased cellularity, mitoses and cellular atypism, and facilitated diagnosis. Pathologic samples taken from areas of increased Lac/Cr ratio showed predominant feature of necrosis. 1H CSI was feasible with the stereotactic headframe in place. The final pathologic results obtained were concordant with the local metabolic information from 1H CSI. We believe that 1H CSI-directed stereotactic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting. © 2003 Elsevier Science Inc. All rights reserved

High Resolution MR Images from 3T Active-Shield Whole-Body MRI System

PURPOSE: Within a clinically acceptable time frame, we obtained the high resolution MR images of the human brain, knee, foot and wrist from 3T whole-body MRI system which was equipped with the world first 3T active shield magnet. MATERIALS AND METHODS: Spin echo (SE) and Fast Spin Echo (FSE) images were obtained from the human brain, knee, foot and wrist of normal subjects using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. For acquisition of MR images of knee, foot and wrist, we employed a homemade saddle shaped RF coil. Typical common acquisition parameters were as follows: matrix= 512x512, field of view (FOV) = 20 cm, slice thickness = 3 mm, number of excitations (NEX) = 1. For T1-weighted MR images, we used TR= 500 ms, TE = 10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE = 108 ms. RESULTS: Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.5T system. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. CONCLUSION: The present results demonstrate that the MR images from 3T system could provide better diagnostic quality of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods

Neurometabolic Improvement in Parkinson\u27s Disease After Stereotactic Functional Neurosurgery by Follow-Up MR Spectroscopy

PURPOSE - To investigate neurometabolism from the brain destructive lesions and striatal putamen-pallidus regions to the clinically worst side in patients with Parkinson\u27s disease after stereotactic functional neurosurgery. METHODS - Using proton magnetic resonance spectroscopy ($^1$H MRS), fifteen patients (7 males and 8 females; mean age 56.5 years; age range 43-67 years) with Parkinson\u27s disease (PD) were studied to measure N-acetylaspartate (NAA), creatine (Cr), choline-containing compounds (Cho) and lactate (Lac) levels on the neurosurgical lesions of thalamus, globus pallidus and striatal putamen-pallidus regions in a brain. RESULTS - Brain destructive lesion and striatal putamen-pallidus region in PD compared with controls were highly and significantly related to NAA/Cho ratios reduction, respectively (P =0.002, P =0.04), but showed no difference from the same regions of PD prior to neurosergery (P =0.06, P =0.77). Increased lactate peaks at 1.3 ppm were present in all the cerebral lesions, and these resonances were confirmed at a long TE =136 ms, indicating that these signals distinguished from lipids. CONCLUSIONS - Our results suggest that NAA/Cho ratios may provide as a neurometabolite marker for neurochemical changes in brain surgical lesion, and the ratios might be related to functional change of neuropathophysiological status in the striatal putamen-pallidus region of PD. Increase of lactate signals, being remarkable in surgical lesions, could be consistent with a common consequence of surgical necrosis. Therefore, MR spectroscopy could be a sensitive diagnostic tool in monitoring neurometabolic changes in PD with neurosurgical treatment

Proton MR Spectroscopic Changes in Parkinson\u27s Diseases After Thalamotomy

To investigate whether there are significant changes in regional brain metabolism in patients with Parkinson\u27s disease before and after thalamotomy using proton magnetic resonance spectroscopy (1H MRS). Fifteen patients underwent 15 stereotactic thalamotomies for control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was carried out on a 1.5 T unit using stimulated-echo acquisition mode (STEAM) sequence (TR/TM/TE, 2000/14/20 ms). Spectra were obtained from substantia nigra, thalamus and putamen areas with volumes of interests (7-8 ml) in patients before and after the surgery. Metabolite ratios of NAA/Cho, NAA/Cr and Cho/Cr were calculated from relative peak area measurements. We evaluated alterations of metabolite ratios in brain metabolism in Parkinson\u27s disease patients with clinical outcome following thalamotomy. NAA/Cho ratios showed generally low levels in substantia nigra and thalamus in Parkinson\u27s disease patients with clinical improvement following thalamotomy. In 80% (12/15) patients, decreased NAA/Cho ratios were observed from the selected voxels in substantia nigra after thalamic surgery \u3c0.05). The ratios were also significantly decreased in thalamus in 67% (10/15) patients with clinical improvement (\u3c0.05). Our results suggest that NAA/Cho ratio may be a valuable criterion for evaluation of Parkinson\u27s disease patients with the clinical improvement following surgery. 1H MRS may be a useful utility for the aid in better understanding the pathophysiologic process in Parkinson\u27s disease patients on the basis of the variation of NAA/Cho ratio. © 2002 Elsevier Science Ireland Ltd. All rights reserved