199 research outputs found
La Orogenia Cadomiense y el rifting del Paleozoico Inferior en el Sudoeste de Iberia
La intensidad y la duración de la Orogenia Cadomiense en el sudoeste de Iberia han sido temas controvertidos. El magmatismo calcoalcalino del Vendiense superior, que se encuentra ampliamente representado en la Zona de Ossa Morena, es el efecto orogénico cadomiense más significativo. Además, en las rocas del Proterozoico superior que afloran en Peraleda del Zaucejo (sur de la Zona Centroibérica) se ha establecido firmemente la existencia de foliación y metamorfismos tardiprecámbricos. En la Zona de Ossa Morena, sin embargo, la deformación penetrativa de las rocas precámbricas parece corresponder casi exclusivamente a pliegues y cabalgamientos de edad varisca. En conjunto, la intensidad de la orogenia cadomiense en el sudoeste de Iberia es, como en el resto del Macizo Ibérico, moderada. Los datos geocronológicos existentes aparentan la existencia de un magmatismo initerrumpido desde el Proterozoico superior hasta el Ordovícico; sin embargo, se sugiere que tal continuidad no es real. Del análisis de los datos estratigráficos se deduce que la orogenia cadomiense se habría desarrollado exclusivamente en el Proterozoico terminal, siendo el Cámbrico inferior un período de transición entre el ciclo orogénico cadomiense y el ciclo varisco. Desde el Cámbrico Inferior alto, se desarrolló en la Zona de Ossa Morena el rifting pre-varisco, cuyo reflejo estratigráfico es la sustitución de carbonatos de plataforma (Cámbrico Inferior) por sedimentos terrígenos y rocas volcánicas. Localmente, el rifting pre-varisco originó una fábrica milonítica y un metamorfismo de grado medio-alto, como el que se observa en Valuengo y en Monesterio. Como consecuencia del rifting cambro-ordovícico, la Zona de Ossa-Moreno debió de ser en el Silúrico un fragmento aislado de corteza continental
Two-Sample Two-Stage Least Squares (TSTSLS) estimates of earnings mobility: how inconsistent are they?
Academics and policymakers have shown great interest in cross-national comparisons of intergenerational earnings mobility. However, producing consistent and comparable estimates of earnings mobility is not a trivial task. In most countries researchers are unable to observe earnings information for two generations. They are thus forced to rely upon imputed data from different surveys instead. This paper builds upon previous work by considering the consistency of the intergenerational correlation (ρ) as well as the elasticity (β), how this changes when using a range of different instrumental (imputer) variables, and highlighting an important but infrequently discussed measurement issue. Our key finding is that, while TSTSLS estimates of β and ρ are both likely to be inconsistent, the magnitude of this problem is much greater for the former than it is for the latter. We conclude by offering advice on estimating earnings mobility using this methodology
Control de la enfermedad de Chagas a traves del mejoramiento de la vivienda : informe final; sectores salud y social
ESTUDIO COMPARATIVO ENTRE CORRELACIONES EMPÍRICAS Y MODELOS MECANÍSTICOS PARA FLUJO MULTIFÁSICO EN POZOS HORIZONTALES DE INYECCIÓN DE VAPOR
RESUMENLa inyección de vapor en pozos horizontales tiene gran aplicabilidad en yacimientos de crudo pesado. Sin embargo,uno de los retos de esta tecnología es la predicción de los perfiles de presión, temperatura y calidad del vapor alo largo del pozo. Por más de 30 años, se han utilizado correlaciones empíricas para determinar estos perfiles,las cuales presentan errores cercanos al ± 30%. En los últimos años se ha dado mayor énfasis a los modelosmecanísticos, ya que permiten obtener perfiles hidráulicos más ajustados a la realidad y adicionalmente predicenlos patrones de flujo que se presentan en las tuberías.En este trabajo se evalúa el desempeño de tres modelos mecanísticos y cinco correlaciones utilizadas comúnmentepara predecir el gradiente de presión en flujo bifásico (vapor húmedo), con aplicación a pozos horizontales,compuestos por una sección de tubería vertical y otra horizontal. El gradiente de presión calculado con cadamodelo es comparado con el gradiente de presión experimental tomado de dos casos reportados en la literatura.Se presentan estimaciones del error del gradiente de presión medido versus el calculado por cada modelo. En laevaluación, dos modelos mecanísticos estudiados arrojan errores absolutos promedio menores del 10%.Palabras claves: Flujo multifásico, modelos mecanísticos, patrones de flujo, correlaciones, holdup.ABSTRACTThe steam injection in horizontal wells has great applicability to heavy oil reservoirs. However, one of thechallenges of this technology is the prediction of the profiles of pressure, temperature and vapor quality along thewell. For over 30 years, empirical correlations were used to determine these profiles, which have errors close to ±30%. In recent years there has been greater emphasis on mechanistic models, allowing hydraulic profiles get moreadjusted to reality and further predict the flow patterns that occur in the pipes.This paper evaluates the performance of three mechanistic models and five correlations commonly used to predictthe pressure gradient in two-phase flow (wet steam), with application to horizontal wells, consisting of a verticalpipe section and other horizontal pipe section. The pressure gradient calculated with each model is compared withthe experimental pressure gradient taken from two cases reported in the literature. We present error estimates of thepressure gradient measured versus calculated for each model. In the evaluation, two studied mechanistic modelsobtained lower mean absolute error of 10%.Keywords: mechanistic models, steam injection, horizontal wells, flow pattern
Concordancia interexaminador de hallazgos periodontales utilizando radiografía periapical convencional
Introducción: la enfermedad periodontal afecta más de la mitad de la población en Colombia siendo estimada una de las primeras causas de morbilidad oral. Las ayudas diagnósticas que permitan la evaluación de su extensión y severidad resultan de importancia puesto que así se tendrán herramientas confables para cuantifcar la gravedad del problema. Objetivo: determinar la concordancia interexaminador para la detección de hallazgos radiográfcos en pacientes con periodontitis crónica localizada empleando radiografía periapical convencional. Métodos: estudio de pruebas diagnósticas incluyendo pacientes con periodontitis crónica localizada, sobre el diente con peor nivel de inserción clínico y a través de una sola radiografía convencional por órgano dentario empleando técnica de paralelismo. Las valoraciones radiográfcas fueron realizadas por dos evaluadores independientes y cegados para los hallazgos: lámina dura, defectos óseos y tipo de defecto. El acuerdo obtenido se estimó a través de Kappa de Cohen. Resultados: se tomaron en total 125 radiografías. La edad promedio fue 38,8±9,9 años, y 61,6% eran mujeres. La concordancia para lámina dura fue 0,08 (IC 95 %: -0,04 – 0,21), defectos óseos 1,00 (IC 95 %: 1,00 – 1,00); tipo de defecto presente 0,31 (IC 95 %: 0,29 – 0,38). Conclusiones: la concordancia se evaluó como nula, casi perfecta y aceptable para los hallazgos lámina dura, presencia de defectos óseos y tipo de defecto respectivamente. Para algunos hallazgos y dada la importancia de los procesos diagnósticos y terapéuticos se necesitan valoraciones más exactas que se traduzcan en un mayor grado de acuerdo.Introduction: periodontal disease affects more than 50% of the Colombian population being considered as one of the main causes of oral morbidity. Diagnostic tests that could evaluate its extension and severity are important since we can account then for reliable tools to quantify the disease severity. Objetive: To estimate the interrater reliability for the detection of radiographic fndings in chronic periodontitis patients using conventional periapical radiography. Methods: It was performed a diagnostic test study including patients diagnosed with untreated localized chronic periodontitis including the worst prognosis tooth and performing a single conventional radiography using parallelism technique. We assigned a code for each radiograph and two independent and blinded assessors performed radiographic measurements for the following fndings: lamina dura, presence of bone defects and defect type. Agreement evaluation was performed through Cohen’s Kappa statistic. Results: We evaluated 125 radiographs. Average age was 38,8±9,9 years from whose 61,6 % were female patients. Reproducibility for lamina dura was 0,08 (95% CI: -0,04 – 0,21); bone defects 1,00 (95% CI: 1,00 – 1,00) and type of bone defects 0,31 (95% CI: 0,29 – 0,38). Conclusions: reliability for lamina dura assessment was considered null, for bone defects almost perfect while for type of bone defect acceptable. For some fndings it is necessary accurate assessments, which could refect higher agreement due to the importance of diagnostic and treatment plan establishment. 
Seismic imaging and modelling of the lithosphere of SW-Iberia.
[EN]Data from a closely spaced wide-angle transect has been used to study the middle-to-lower crust and the Moho in SW-Iberia. A low-fold wide-angle stack image reveals a highly heterogeneous seismic signature at lower-crustal levels changing laterally along the profile. The lower crust features an irregular distribution of the reflectivity that can be explained by a heterogeneous distribution of physical properties. The Moho discontinuity also features a high variability in its seismic character that correlates with the different tectonic terranes in the area. A 2D finite difference code was used for solving the elastic wave equation and to provide synthetic wide-angle shots. Relatively simple layer cake model derived from conventional refraction interpretation generates the main events of the shot records. However, these models cannot account for the lateral variability of the seismic signature. In order to obtain more realistic simulations, the velocity model was modified introducing stochastic lensing at different levels within the crust. The Moho was modelled as a 3 km thick layered structure. The resulting average velocity models include a high velocity layer at mid-crustal depth, a highly reflective lower crust and a relatively thin horizontal Moho. This heterogeneous model can be achieved by lensing within the crust, a layered mafic intrusion and a strongly laminated lower crust and Moho
Etiology of chronic urticaria: the Ecuadorian experience
Background: The purpose of this study was to identify chronic urticaria (CU) etiologies and treatment modalities in Ecuador. We propose that the sample distribution fits the expected one, and that there is an association between the etiology and its treatment.
Methods: We performed a retrospective study involving 112 patients diagnosed with CU using a Checklist for a complete chronic urticaria medical history. Demographic and clinical variables were collected. The etiology of CU was classified using the EAACI/GA2LEN/EDF/WAO guideline. Descriptive analyses were performed for demographical and clinical variables. Chi square tests were applied to analyze the fit of distribution and the independence of variables. P values less than 0.05 were considered significant.
Results: Among all the patients, 76.8% were diagnosed with chronic spontaneous urticaria (CSU), of which 22.3% had a known etiology or possible exacerbating condition. Food allergy was identified as the most common accompanying condition in patients with CSU (10.7%) (p < 0.01).. On the other hand, 23.2% inducible urticarias (CIndU) were indentified; dermographism was the most common (10.7%) (p < 0.01). Regarding treatment regimens, sg-H1-antihistamines alone represented the highest proportion (44.6%). The combination of any H1-antihistamine plus other drug was a close second (42.0%) (p < 0.01). Almost 48% of CSUs of unknown etiology were treated with any antihistamine plus another drug. In patients with known etiology, sg-antihistamines alone (44.0%) was the most common management. In addition, 53.8% of CIndUs were treated with sg-antihistamines alone. Though, these associations were not statistically significant.
Conclusion: CSU is the most frequent subtype of CU. Modern non-sedating antihistamines in licensed doses are the drug of choice. Nevertheless, a great proportion of patients require the addition of another type of medication
Successful management of peri-implantitis around short and ultrashort single-crown implants: a case series with a 3-year follow-up
Introduction and Aim. In case of peri-implantitis, resective surgery is contraindicated for short and ultrashort implants, limiting the treatment options to regenerative surgery or to implant removal. 'is retrospective case series presents the clinical and radiographic outcomes of a surgical regenerative procedure to treat peri-implantitis around short and ultrashort implants. Materials and Methods. The study is a retrospective evaluation of patients suffering from peri-implantitis and those who underwent access flap surgery, concomitant chemical and mechanical decontamination of implant surface, and bone grafting using a self-hardening mixture of bone substitutes and biphasic calcium sulfate. No membranes were applied to cover the grafting material, and primary tension-free closure was achieved. The retrospective protocol was reviewed and approved by the Ethics Committee for Clinical Sperimentation (CESC) of Verona and Rovigo, Italy (based in the University of Verona) (Prog. 1863CESC. Date of approval: 2018-07-04). Results. 15 patients (17 implants) have been diagnosed with peri-implantitis after a mean follow-up of 24 months after loading. Implant length was between 5 and 8 mm. 8 patients (10 implants) had a history of periodontitis. At baseline, the mean PD (probing pocket dept) at the deepest site was 8.12 mm, with an average mBI (modified bleeding index) of 2.35 and a mean BD (bone defect depth) of 3.04 mm. At the 3-year follow-up, the CSR was 100%, the mean mBI was 0.88 (average reduction: - 1.47), the mean PD was 3.35 mm (mean PD reduction: 4.77 mm), and the mean bone defect was reduced by 1.74 mm, with a mean bone fill of 55%. Conclusions. The results of the present case series suggest that if accurate surface decontamination is achieved, high survival rate and good clinical and radiographic results can be obtained after 3 years. However, only the histological examination could confirm the growth of new bone in direct contact with the implant surface or if the grafted material only fills the space left by the peri-implant defect
Durabilidad del aluminio desnudo y anodizado en atmósferas de muy diferentes corrosividades. I. Aluminio desnudo
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