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Modelado matemático del efecto del anclaje sobre el sesgo de subconfianza  [cached]
Guillermo Macbeth,Eugenia Razumiejczyk
Revista de Psicología , 2012,
Abstract: Mathematical modelling of the anchoring effect on the underconfidence bias The anchoring effect is defined as the tendency of human thought to the fixation on certain pieces of information that affect decision-making. In the same context, the underconfidence bias is understood as an agent’s propensity to underestimate his or her own objective performance. While some aspects of these phenomena are well known, there are no formal models that specifically describe the relationship between both. This paper presents: i) an experiment that illustrates the anchoring effect on the underconfidence bias by both reducing and amplifying such bias in the domain of geographic decision tasks and ii) the foundations of a new mathematical model that promotes precision in the study of the relationship between anchoring and underconfidence. Se define el efecto de anclaje como la tendencia del pensamiento humano a la fijación en determinados fragmentos de información que afectan la toma de decisiones. El sesgo de subconfianza, por su parte, se entiende como la propensión de un agente a subestimar su desempe o objetivo. Si bien se conocen algunos aspectos de la interacción entre ambos efectos, no se dispone de modelos formales que describan tal relación específica. Este estudio presenta: i) un experimento que pone en evidencia el efecto que ejerce el anclaje tanto para reducir, como para amplificar la subconfianza en tareas de decisión geográfica y ii) los fundamentos de un modelo matemático novedoso que permite estudiar con mayor precisión la relación del anclaje con la subconfianza
Transfer and anchorage bond behaviour in self-compacting concrete
Martí-Vargas, J. R.,Serna-Ros, P.,Arbeláez, C. A.,Rigueira-Víctor, J. W.
Materiales de Construccion , 2006,
Abstract: Self-compacting concretes (SCC) provide solutions to the problems facing precast concrete construction, enhancing competitiveness, reducing turnaround times and improving final product quality. SCC is fast becoming a key product for the future development of the precast pre-stressed concrete industry. The present paper compares the bond performance of SCC and traditional concrete (TC). The bond performance results confirm the viability of SCC in precast pre-stressed concrete manufacture, despite a slightly higher loss of pre-stressing force and slightly greater anchorage lengths in SCC with a low water/cement ratio. No differences in transfer or anchorage length were detected,however, when high strength TC and SCC were compared. The ECADA test method proved to be well suited to detecting the differences between the concretes analyzed. El desarrollo de los hormigones autocompactantes (SCC)ofrece muchas posibilidades a las construcciones con hormigón prefabricado, aumentando su competitividad, reduciéndolos plazos de fabricación y ofreciendo mejoras en la calidad del producto final. El SCC se está convirtiendo en un producto clave para el futuro desarrollo de la industria de prefabricados de hormigón pretensado.En este estudio se compara el comportamiento adherente de los SCC con el de los hormigones tradicionales (TC) actuales. Los resultados obtenidos confirman la viabilidad del uso de los SCC para la fabricación de elementos prefabricados con hormigón pretensado, en lo relativo a su comportamiento adherente, aunque con la necesidad de considerar unas pérdidas de pretensado ligeramente mayores. Asimismo,debe esperarse un ligero aumento de las longitudes de anclaje cuando se trabaje con SCC de baja relación agua/cemento. Sin embargo, no se han detectado diferencias de comportamiento entre ambos tipos de hormigón cuando la resistencia a compresión es alta en lo relativo a las longitudes de transmisión y anclaje. El método de ensayo ECADA muestra una buena adecuación para detectar las diferencias de comportamiento entre los hormigones analizados
Anclaje de barras en zapatas de hormigón
Calavera, J.
Informes de la Construccion , 2009,
Abstract: The paper analyzes the simplified rule for footing whereby the anchorage length is developed from a distance equal to 0,5 h, measured form the end of the footing. This simplification is based on the assumption that the footings involved are stiff, but Eurocode EC-2 fails to mention that fact, while Spanish code EHE-08 prescribe the rule for flexible footing. The value of the soil contact pressure σt notwithstanding, the shallower a footing is, the more economical. Consequently, for soils with σt ≤ 0,2 N/ mm2 the right solution could differs from the rules laid down in the above two standards. Se analiza la regla simplificada de suponer, que para zapatas, el desarrollo de la longitud de anclaje se cuenta a 0,5 h a partir del extremo de las barras, para la tensión .que tenga la barra en ese punto. Esta simplificación, está basada en la hipótesis de zapata rígida, pero el Eurocódico EC-2 no lo dice y la Instrucción EHE-08 la fija para zapatas flexibles. Como para todas las presiones σt de contacto con el suelo, la zapata más económica es la de menor canto posible, para suelos con σt ≤ 0,2 N/mm2 la solución correcta puede diferir notablemente de la regla establecida por ambas Normas.
Caracterización del Traumatismo Dentoalveolar que Afecta a los Tejidos de Soporte en Dientes Temporales
ávila Rivera,Claudia; Cueto Urbina,Alfredo; González Ríos,Jenniffer;
International journal of odontostomatology , 2012, DOI: 10.4067/S0718-381X2012000200007
Abstract: the purpose of pursuing this research is to evaluate the distribution of dentoalveolar trauma in time by gender, age, etiology, where the injury occurs, diagnosis of trauma, and treatment affected teeth done. the sample corresponds to 207 children benefiting from pediatric dentist referral center simon bolivar, ages 1 to 7 years who suffered dentoalveolar trauma of the anterior teeth during the years 2005-2007 which corresponds according to the classification proposed by andreasen, injuries affecting the tooth supporting tissue, including: subluxation, lateral luxation, intrusive luxation, extrusive luxation and avulsion. the results obtained allow us to observe a higher percentage of trauma to the male gender with 60% being the most common age between 4 and 6, the upper central incisors are the teeth most affected (39-40%). the most common etiology corresponds to a 25% fall, this being more prevalent in school or kindergarten (20%). as for the diagnosis of dentoalveolar trauma subluxation the majority are present in 53% of cases. the control and indication is the treatment most used in these dentoalveolar traumas.
Crecimiento anormal del grano austenítico en el acero microaleado 38MnSiV55 y determinación de las fuerzas impulsoras y de anclaje  [cached]
Medina, S. F.,Chapa, M.,Gómez, M.,Quispe, A.
Revista de Metalurgia , 2003,
Abstract: Several castings of 38MnSiVS5 steel have been manufactured with different titanium and aluminium contents and the austenitic grain size has been determined at temperatures between 900 and 1200 °C. The volume fraction of normal and abnormal grain growth have been quantified. The results show that abnormal growth of the austenitic grain occurs irrespective of the titanium and aluminium contents, due fundamentally to the partial dissolution of TiN precipitates. The steels with high aluminium contents have presented worse behaviour due to the formation of a second type of precipitates, namely AIN, which quickly dissolve between 1000 and 1100 °C, causing a drastic decline in the local pinning forces which gives rise to more pronounced abnormal growth of the affected grains. In parallel, a study of the precipitates has been carried out by transmission and scanning microscopy, allowing the calculation of pinning forces according to Zener and Gladman expressions and the establishment of a comparison with driving forces. This comparison makes it possible to explain the differences encountered between the different castings. Se fabricaron varias coladas del acero 38MnSiV55 con diferentes contenidos de titanio y aluminio, y se determinó el tama o del grano austenítico a temperaturas comprendidas entre 900 y 1.200 °C. Se cuantificaron las fracciones de volumen de crecimiento normal y anormal, respectivamente. Los resultados muestran que el crecimiento anormal del grano austenítico ocurre independientemente de los contenidos de titanio y aluminio, debido, fundamentalmente, a la disolución parcial de los precipitados TiN. Aquellos aceros con porcentajes altos de aluminio mostraron un peor comportamiento debido a que la formación de un segundo tipo de precipitados, concretamente AIN, y su pronta disolución entre 1.000 y 1.100 °C, ocasiona un descenso drástico en las fuerzas de anclaje locales, lo que produce un crecimiento anormal más pronunciado de los granos afectados. Paralelamente, se realizó un estudio de los precipitados por Microscopía de Transmisión y de Barrido (MTB), que permitió calcular las fuerzas de anclaje de acuerdo con las expresiones de Zener y Gladman y establecer una comparación con las fuerzas impulsoras de crecimiento de grano. Dicha comparación permite explicar las diferencias encontradas entre las distintas coladas.
Influencia del sobrepase y la incompetencia bilabial como factores predisponentes de traumatismos dentoalveolares Influence of overpass and the bilabial incompetence like predisposing factors of dentoalveolar traumata
Yarisleydis Pérez Cordero,María Elena Fernández Collazo,Agustín Rodríguez Soto,Dadonim Vila Morales
Revista Cubana de Estomatolog?-a , 2011,
Abstract: En un 95 % de los casos que presentan vestibuloversión de incisivos superiores con incompetencia bilabial, originada fundamentalmente por hábitos bucales deformantes, está presente el traumatismo dentoalveolar. Se realizó un estudio descriptivo de corte transversal sobre los traumatismos dentoalveolares en un grupo de pacientes de edades comprendidas entre 0 y 15 a os, durante los meses de enero a diciembre del a o 2009, en el Policlínico Universitario "Antonio Pulido Humarán", La Habana, Cuba. El propósito fue relacionar el sobrepase dentario anterior y la competencia labial con los traumatismos dentoalveolares. La información se obtuvo a través del interrogatorio y por el método de la observación, mediante los exámenes clínico y radiográfico. Se encontró que la mayor presencia de traumatismos dentales estuvo en los pacientes afectados por maloclusiones (76,8 %), y dentro de ellas se encontró un sobrepase de un tercio de la corona en 47,2 % de los pacientes. El trauma de mayor aparición fue la fractura coronaria no complicada (46,6 %). En cuanto a la relación bilabial se observó el predominio de la incompetencia labial en pacientes con traumas dentarios portadores de maloclusiones. Los dientes más afectados fueron los incisivos centrales superiores. In the 95 % of cases presenting vestibuloversion of upper incisors with bilabial incompetence provoked mainly due to deforming oral habits, it is present the dentoalveolar trauma. To relate the anterior dental overpass, the labial incompetence according to the tooth involved as well as to assess the potential relation between the types of dentoalveolar traumata suffered, according the dental overpass and the bilabial relation, a cross-sectional and descriptive study was conducted on the dentoalveolar traumata in a group of patient aged between 1 and 15 from January to December, 2009 in the "Antonio Pulido Humarán" University Polyclinic, La Habana, Cuba. Information was gathered by questioning and by observational method by clinical and radiographic examinations. In study was evidenced that the great representation of dental traumata was in the patients involved by malocclusions for a 76.8 % including a overpass of a third of crown in the 47.2 % of patients. The more frequent trauma was the coronary fracture non-complicated in the 46.6 %. In the bilabial relation there was predominance of bilabial incompetence (53.6 %) in patients presenting with traumata with malocclusion. The teeth more involved were the central upper incisors.
The use of the Pendulum appliance for distal movement of first maxillary molars.  [PDF]
S. Sidiropoulou,I. S. Papageorgiou
Hellenic Orthodontic Review , 2002,
Abstract: This paper describes in details the Pendulum appliance and its use for the distal movement of first maxillary molars. This appliance has the advantage that it does not require patient compliance and achieves significant distal movement of maxillary first as well as of second permanent molars. Its effect is mainly dentoalveolar, but indirect effects, mostly skeletal, have also been observed on the vertical dimension. The Pendulum appliance is a reliable alternative for the distal movement of first maxillary molars.
Dentoalveolar changes following maxillary distraction osteogenesis  [PDF]
Lili Yang, Eduardo Yugo Suzuki, Boonsiva Suzuki
Open Journal of Stomatology (OJST) , 2013, DOI: 10.4236/ojst.2013.38071
Abstract:

The purpose of this study was to compare the dentoalveolar changes produced when using two different intraoperative surgical procedures for maxillary distraction osteogenesis. Eight patients were assigned into two groups according to the surgical procedure: down-fracture (DF, n = 6) vs non-down-fracture (NDF, n = 2). Lateral cephalograms and 3-D models before and after maxillary distraction were analyzed. The Mann-Whitney U test was used to compare the differences in the amounts of advancement and dento-alveolar changes between the DF and NDF groups. The significance level was established at 0.05. Although a significantly greater amount of maxillary movement was observed in the DF group (10.0 mm ± 2.2) than in the NDF group (5.9 mm ± 2.3), significantly greater arch length (8.7 mm ± 5.2) and arch width changes (6.0 mm ± 1.0) were observed in the NDF group than in the DF group, (arch lengths 3.0 mm ± 1.1 and arch width changes 3.2 mm ± 2.0). A significantly greater amount of dental anchorage loss was observed in the NDF group. The use of the NDF procedure resulted in greater amounts of dental anchorage loss than resulted from the DF procedures when tooth-borne devices were used during maxillary distraction osteogenesis. The type of surgical procedure might play an important role in the amount and direction of the dental changes.

Comportamiento de los traumatismos dentoalveolares en alumnos de las ESBU del municipio Artemisa Behaviors of dentoalveolar traumata present in urban basic secondary schools (UBSS) pupils of Artemisa municipality  [cached]
Mileydis Vi?as García,Yudit Algozaín Acosta,Ricardo Rodríguez Llanes,Licerba álvarez Campo
Revista Cubana de Estomatolog?-a , 2009,
Abstract: El trauma dentoalveolar (TDA) es un problema de salud pública debido a su incidencia y a las graves secuelas que puede dejar. Se realizó un estudio descriptivo, retrospectivo y de corte transversal para determinar el comportamiento de los TDA en alumnos de las escuelas secundarias básicas urbanas del municipio Artemisa en el período comprendido entre enero y junio de 2008. El universo fue de 2 684 alumnos y de estos, 309 constituyeron la muestra al estar afectados por algún tipo de TDA. A los afectados se le registraron las siguientes variables: escuela, edad, sexo, etiología del TDA, período en que ocurrió el TDA, arcada afectada, diente lesionado y tipo de lesión. Para recoger los datos se confeccionó un formulario y estos se procesaron estadísticamente por el sistema Excel (INSTAT). Los resultados se presentaron en tablas y gráficos. Se constató que del total de alumnos examinados, sólo el 11,5 % resultó afectado, con un comportamiento homogéneo del TDA en las cuatro ESBU. Al distribuirlos por sexo, aproximadamente más de la mitad correspondió al masculino y el intervalo de edad de mayor número de afectados fue de 11-12 a os. La principal causa de TDA fueron las caídas y el mayor por ciento del total de TDA ocurrió durante el período vacacional. La arcada superior fue la más propensa a los TDA y fueron los centrales los dientes más afectados. La pérdida de tejido coronario representó más de la mitad de las lesiones producidas por los TDA. The dentoalveolar trauma (DAT) becomes a public health problem due to its significant incidence and the future severe sequalae. A cross-sectional, retrospective and descriptive study was conducted to determine the behavior of DATs in pupils of urban basic secondary schools of Artemisa municipality from January to June, 2008. Sample includes 2 684 pupils and from these, 309 were the real sample who was affected by some kind of DAT. In this group the following variables were registered: school, age, sex, DAT etiology, period of DAT, involved arch, involved tooth and the kind of lesion. For data collection, we designed a form and these were statistically processed by Excel system (INSTAT). Results were showed in tables and charts. We conclude that from the total of pupils examined; only the 11.5% was affected with a DAT homogenous behavior in the four basic secondary schools. In distribution by sex, almost the was of male sex and the age interval with higher involvement was of 11-12. The leading cause of DAT was the teeth loss and the great percentage of DAT total occurred during vacations period. The superior arch w
Evaluation of care of dentoalveolar trauma
Fariniuk, Luiz Fernando;Souza, Maria Helena de;Westphalen, Vania Portela Dietzel;Carneiro, Everdan;Silva Neto, Ulisses X.;Roskamp, Liliane;Cavali, Ana égide;
Journal of Applied Oral Science , 2010, DOI: 10.1590/S1678-77572010000400004
Abstract: objectives: the aim of this study was to evaluate cases of dental trauma treated at the specialized center of pontifical catholic university of paraná, curitiba, brazil, during a period of 2 years. material and methods: a total of 647 patients were evaluated and treated between 2003 and 2005. data obtained from each patient were tabulated and analyzed as to gender, age, etiology, time elapsed after the injury, diagnosis (type of trauma), and affected teeth. results: the results revealed that male individuals aged 7 to 13 years presented the highest prevalence of injury, and falling was the main causal factor. in most cases, the time elapsed between the accident and the first care ranged from 4 to 24 h. a total of 1,747 teeth were affected, with higher incidence of concussion/subluxation and coronal fracture, followed by lateral luxation and avulsion. the permanent maxillary central incisors were the most commonly affected teeth. conclusion: the frequency and causes of dentoalveolar trauma should be investigated for identification of risk groups, treatment demands and costs in order to allow for the establishment of effective preventive measures that can reduce the treatment duration and costs for both patients and oral health services.
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