1,028 research outputs found
Actividades colaborativas en la educación en y para el trabajo entre niñas y niños en una comunidad p'urhépecha
Este texto tiene la finalidad de presentar los resultados de una investigación enfocada a indagar actividades que realizan niñas y niños de entre ocho y diez años en la comunidad p’urhépecha de Cherán, Michoacán, en contextos familiares y comunitarios. Su análisis e interpretación parte de una perspectiva antropológica y sociocultural. En lo particular, busco aclarar cuáles y de qué manera estas actividades están vinculadas con una educación en y para el trabajo, y cuáles son los propósitos educativos que las madres y los padres relacionan con las actividades de sus hijos.ITESO A.C
Single image geometry inspection using inverse endoscopic fringe projection
Fringe projection is an important technology for the measurement of free form elements in several application fields. It can be applied to measure geometry elements smaller than one millimeter. In combination with deviation analysis algorithms, errors in fabrication lines can be found promptly to minimize rejections. However, some fields cannot be covered by the classical fringe projection approach. Due to shadowing, filigree form elements on narrow or internal carrier geometries cannot be captured. To overcome this limitation, a fiberscopic micro fringe projection sensor was developed [1]. The new device is capable of resolutions of less than 15 m with uncertainties of about 35 m in a workspace of 3x3x3 mm. Using standard phase measurement techniques, such as Gray-code and cos-patterns, measurement times of over a second are too long for in-situ operation. The following work will introduce an approach of applying a new single image measuring method to the fiberscopic system, based on inverse fringe projection [2]. The fiberscopic fringe projection system employs a laser light source in combination with a digital micro-mirror device (DMD) to generate fringe patterns. Fiber optical image bundles (FOIB) are used as well as gradient-index lenses to project these patterns on the specimen. This advanced optical system creates high demands on the pattern generation algorithms to generate exact inverse patterns for arbitrary CAD-modelled geometries. Approaches of optical simulations of the complex beam path and the drawbacks of the limited resolutions of the FOIBs are discussed. Early results of inverse pattern simulations using a ray tracing approach of a pinhole system model are presented.DFG/CRC/TR 7
Transformaciones culturales y generacionales en la participación colaborativa de niñas y niños de una comunidad p´urhépecha
Este artículo presenta los resultados de una investigación sobre la participación
colaborativa y aprendizajes de niñas y niños de una comunidad p’urhépecha en las
actividades de la vida diaria de sus familias. Planteamos que los padres orientan estas
formas de participación siguiendo sus concepciones acerca de qué actividades son
pertinentes al desarrollo de sus hijos. Los resultados de entrevistas realizadas a padres
con poca experiencia escolar y a otros que se distinguen por su amplia historia personal
en relación con la institución escolar, muestran diferencias culturales al interior de
la comunidad y transformaciones generacionales entre las familias en el involucramiento
de los hijos en actividades colaborativas que repercuten en su desarrollo como
miembros que contribuyen a la familia y la comunidad.
This article presents the results of research on children’s collaborative participation and learning in the daily family activities of a P’urhépecha community. We believe that parents orient forms of participation according to their conceptions of pertinent activities for their children’s development. The results of interviews with parents who have little educational experience and with other parents who are known for a long personal history with school, show cultural differences within the community and generational transformations among families in terms of their children’s involvement in collaborative activities—which reflect on their development as individuals who contribute to their family and community.ITESO, A.C
Reproducibility of thoracic kyphosis measurements in patients with adolescent idiopathic scoliosis
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COMPREHENSIVE CALCULATION-BASED IMRT QA USING R&V DATA, TREATMENT RECORDS, AND A SECOND TREATMENT PLANNING SYSTEM
Purpose: Traditional patient-specific IMRT QA measurements are labor intensive and consume machine time. Calculation-based IMRT QA methods typically are not comprehensive. We have developed a comprehensive calculation-based IMRT QA method to detect uncertainties introduced by the initial dose calculation, the data transfer through the Record-and-Verify (R&V) system, and various aspects of the physical delivery.
Methods: We recomputed the treatment plans in the patient geometry for 48 cases using data from the R&V, and from the delivery unit to calculate the “as-transferred” and “as-delivered” doses respectively. These data were sent to the original TPS to verify transfer and delivery or to a second TPS to verify the original calculation. For each dataset we examined the dose computed from the R&V record (RV) and from the delivery records (Tx), and the dose computed with a second verification TPS (vTPS). Each verification dose was compared to the clinical dose distribution using 3D gamma analysis and by comparison of mean dose and ROI-specific dose levels to target volumes. Plans were also compared to IMRT QA absolute and relative dose measurements.
Results: The average 3D gamma passing percentages using 3%-3mm, 2%-2mm, and 1%-1mm criteria for the RV plan were 100.0 (σ=0.0), 100.0 (σ=0.0), and 100.0 (σ=0.1); for the Tx plan they were 100.0 (σ=0.0), 100.0 (σ=0.0), and 99.0 (σ=1.4); and for the vTPS plan they were 99.3 (σ=0.6), 97.2 (σ=1.5), and 79.0 (σ=8.6). When comparing target volume doses in the RV, Tx, and vTPS plans to the clinical plans, the average ratios of ROI mean doses were 0.999 (σ=0.001), 1.001 (σ=0.002), and 0.990 (σ=0.009) and ROI-specific dose levels were 0.999 (σ=0.001), 1.001 (σ=0.002), and 0.980 (σ=0.043), respectively. Comparing the clinical, RV, TR, and vTPS calculated doses to the IMRT QA measurements for all 48 patients, the average ratios for absolute doses were 0.999 (σ=0.013), 0.998 (σ=0.013), 0.999 σ=0.015), and 0.990 (σ=0.012), respectively, and the average 2D gamma(5%-3mm) passing percentages for relative doses for 9 patients was were 99.36 (σ=0.68), 99.50 (σ=0.49), 99.13 (σ=0.84), and 98.76 (σ=1.66), respectively.
Conclusions: Together with mechanical and dosimetric QA, our calculation-based IMRT QA method promises to minimize the need for patient-specific QA measurements by identifying outliers in need of further review
H-1-MRS Measured Ectopic Fat in Liver and Muscle in Danish Lean and Obese Children and Adolescents
This cross sectional study aims to investigate the associations between ectopic lipid accumulation in liver and skeletal muscle and biochemical measures, estimates of insulin resistance, anthropometry, and blood pressure in lean and overweight/obese children.Fasting plasma glucose, serum lipids, serum insulin, and expressions of insulin resistance, anthropometry, blood pressure, and magnetic resonance spectroscopy of liver and muscle fat were obtained in 327 Danish children and adolescents aged 8-18 years.In 287 overweight/obese children, the prevalences of hepatic and muscular steatosis were 31% and 68%, respectively, whereas the prevalences in 40 lean children were 3% and 10%, respectively. A multiple regression analysis adjusted for age, sex, body mass index z-score (BMI SDS), and pubertal development showed that the OR of exhibiting dyslipidemia was 4.2 (95%CI: [1.8; 10.2], p = 0.0009) when hepatic steatosis was present. Comparing the simultaneous presence of hepatic and muscular steatosis with no presence of steatosis, the OR of exhibiting dyslipidemia was 5.8 (95%CI: [2.0; 18.6], p = 0.002). No significant associations between muscle fat and dyslipidemia, impaired fasting glucose, or blood pressure were observed. Liver and muscle fat, adjusted for age, sex, BMI SDS, and pubertal development, associated to BMI SDS and glycosylated hemoglobin, while only liver fat associated to visceral and subcutaneous adipose tissue and intramyocellular lipid associated inversely to high density lipoprotein cholesterol.Hepatic steatosis is associated with dyslipidemia and liver and muscle fat depositions are linked to obesity-related metabolic dysfunctions, especially glycosylated hemoglobin, in children and adolescents, which suggest an increased cardiovascular disease risk
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