Sistemas de cierre sobre algebras de efecto

El presente artículo es un intento de introducir los sistemas de cierre sobre las álgebras de efectos. Primero definiremos sistemas de cierre sobre álgebras de efectos y para el conjunto arbitrario $U$ y el subconjunto arbitrario S de todas las funciones de U a un álgebra de efectos L obtendremos el sistema de cierre que contiene S. Luego definiremos la base de este sistema de cierre y para un subconjunto arbitrario S de todas las funciones desde U hasta un álgebra de efectos L obtendremos la base de este sistema de cierr

Evaluation of consistency rate between clinical and histopathological diagnosis of oral soft tissue lesions

BACKGROUND: Some of the oral lesions including malignant tumors of mesenchymal and epithelial origin have same clinical features. Most of them are white or red patches with undermined edge. Also, in some cases, the microscopic view of histopathologic examination is not diagnostic. So, the integration of clinical and pathological information leads to the correct diagnosis. The aim of this study was the evaluation of consistency rate between clinical and histopathological diagnosis of oral malignant tumors of mesenchymal and epithelial origin.METHODS: This cross-sectional retrospective study was performed in four centers of oral pathology of Hamedan University of Medical Sciences, Hamedan, Iran, during January to June, 2016. The data were collected using the archived files of patients. Collected data from the files included age, sex, lesion location, lesion type, and first and second clinical and histopathologic diagnosis. Finally, histopathological findings were compared with the first and second clinical diagnosis. Data were analyzed using SPSS software.RESULTS: Ninety-one and seventy-nine of studied files were related to men and women, respectively. Most frequent malignant lesion was related to squamous cell carcinoma (SCC) (52.9%), followed by melanoma (29.4%). The consistency rate of first and second clinical and histopathologic diagnosis was 68.2% and 15.2%, respectively. Higher consistency rate was observed in melanoma, SCC, and fibrosarcoma lesions.CONCLUSION: High inconsistency rate between clinical and histopathological diagnosis was found in some cases which may have originated from low diagnostic knowledge of clinicians or their misconception from misdiagnosis. Therefore, the improvement of knowledge and awareness of clinicians by conducting retraining courses is necessary

Language and Arithmetic: A Failure to Find Cross Cognitive Domain Semantic Priming Between Exception Phrases and Subtraction or Addition

We examined cross-domain semantic priming effects between arithmetic and language. We paired subtractions with their linguistic equivalent, exception phrases (EPs) with positive quantifiers (e.g., “everybody except John”) while pairing additions with their own linguistic equivalent, EPs with negative quantifiers (e.g., “nobody except John”; Moltmann, 1995). We hypothesized that EPs with positive quantifiers prime subtractions and inhibit additions while EPs with negative quantifiers prime additions and inhibit subtractions. Furthermore, we expected similar priming and inhibition effects from arithmetic into semantics. Our design allowed for a bidirectional analysis by using one trial's target as the prime for the next trial. Two experiments failed to show significant priming effects in either direction. Implications and possible shortcomings are explored in the general discussion

Influence of citric acid and water on thermoplastic wheat flour/poly(lactic acid) blends. I: Thermal, mechanical and morphological properties

Wheat flour was plasticized with glycerol and compounded with poly(lactic acid) in a one-step twin-screw extrusion process in the presence of citric acid with or without extra water. The influence of these additives on process parameters and thermal, mechanical and morphological properties of injected samples from the prepared blends, was then studied. Citric acid acted as a compatibilizer by promoting depolymerization of both starch and PLA. For an extrusion without extra water, the amount of citric acid (2 parts for 75 parts of flour, 25 parts of PLA and 15 parts of glycerol) has to be limited to avoid mechanical properties degradation. Water, added during the extrusion, improved the whole process, minimizing PLA depolymerization, favoring starch plasticization by citric acid and thus improving phases repartition

Fairness in examination timetabling: student preferences and extended formulations

Variations of the examination timetabling problem have been investigated by the research community for more than two decades. The common characteristic between all problems is the fact that the definitions and data sets used all originate from actual educational institutions, particularly universities, including specific examination criteria and the students involved. Although much has been achieved and published on the state-of-the-art problem modelling and optimisation, a lack of attention has been focussed on the students involved in the process. This work presents and utilises the results of an extensive survey seeking student preferences with regard to their individual examination timetables, with the aim of producing solutions which satisfy these preferences while still also satisfying all existing benchmark considerations. The study reveals one of the main concerns relates to fairness within the students cohort; i.e. a student considers fairness with respect to the examination timetables of their immediate peers, as highly important. Considerations such as providing an equitable distribution of preparation time between all student cohort examinations, not just a majority, are used to form a measure of fairness. In order to satisfy this requirement, we propose an extension to the state-of-the-art examination timetabling problem models widely used in the scientific literature. Fairness is introduced as a new objective in addition to the standard objectives, creating a multi-objective problem. Several real-world examination data models are extended and the benchmarks for each are used in experimentation to determine the effectiveness of a multi-stage multi-objective approach based on weighted Tchebyceff scalarisation in improving fairness along with the other objectives. The results show that the proposed model and methods allow for the production of high quality timetable solutions while also providing a trade-off between the standard soft constraints and a desired fairness for each student

Development of blends of biopolymers based on thermoplastic starch and their compatibilization

Ces travaux de recherche ont porté sur l'élaboration et la compatibilisation de mélanges de matériaux biosourcés à base d'amidon plastifié et de poly (acide lactique). La transformation de l'amidon natif en amidon plastifié est réalisable par extrusion en utilisant des plastifiants. Dans notre étude, les propriétés finales de l'amidon plastifié ont été contrôlées en faisant varier les conditions du procédé (température, temps de séjour, vitesse de rotation des vis) et du matériau (nature et teneur en plastifiant). La plastification de l'amidon par l'eau, le glycérol, le sorbitol et l'acide citrique a ainsi été étudiée. Les mélanges d'amidon plastifié et le poly (acide lactique)(PLA) ont été préparés et caractérisés dans la deuxième partie du travail. Afin d'améliorer la compatibilité de ces polymères, une voie consiste à incorporer un copolymère dans le mélange.Dans ce travail, le copolymère utilisé est un copolymère (Amylose-g-PLA) constitué d'une dorsale amylose et de greffons poly (acide lactique). Une polymérisation en trois étapes a été utilisée pour la synthèse du copolymère dans le but de contrôler la taille et le nombre de greffons de PLA. Deux types de copolymère ont été préparés : le type 1 contenant un nombre élevé de greffons de faible masse molaire et le type 2 contenant un nombre limité de greffons de haute masse molaire. L'efficacité de l'addition de ces copolymères Amylose-g-PLA dans les mélanges (PLA et amidon plastifié) est étudiée dans la dernière partie de ce travail. Une comparaison entre la morphologie et les propriétés mécaniques des mélanges préparées avec ces différents copolymères révèle l'efficacité plus élevée du copolymère de type 1This study dealt with the development and the compatibilization of the blends of plasticized starch and polylactic acid. The transformation of native to plasticized starch is possible by extrusion in the presence of plasticizers. In this work, the final properties of plasticized starch are controlled by changing process parameters (temperature, extrusion time, screw's rotation speed) and nature and quantity of plasticizers. Plasticization of starch by water, glycerol, sorbitol and citric acid is studied. The blends of plasticized starch and poly (lactic acid) (PLA) are prepared and characterized in the second part of this work. To improve the compatibility of the blend, one way is the addition of a copolymer to the mixture to stabilize the dispersed phase in the matrix. The copolymer used in this work (Amylose-g-PLA) is constituted of amylose backbone and poly (lactic acid) (PLA) grafts. The number and the size of the grafted chains of PLA have been controlled by a three step process polymerization. Two copolymer structures have been prepared: type1, containing high numbers of low molar weight PLA grafts and type 2, lower numbers of high molar weight PLA grafts. In the final part, efficiency of these copolymers (Amylose-g-PLA) in these blends is studied. The comparison between morphology and mechanical properties of blends prepared with these copolymers, demonstrate the higher efficiency of type1 copolyme

Inverse Identification of Dynamic Wheel-rail Contact Forces

Accurate evaluation of contact forces between wheel and rail is essential in the assessmentof vehicle performance and to predict consequences of dynamic vehicle-track interaction.As the contact forces can not be measured directly in the field, one common approachis to measure the strain or acceleration at various positions on a wheel or wheel axle.Based on this data, the forces can be estimated. However, the existing schemes typicallyinvolve either a simplified wheel model (neglecting inertia) or, in the case of using moreadvanced models, imply strong restrictions in terms of the choice of spatial and temporaldiscretization of the underlying equations of motion.In this work, the vertical contact force is determined by the solution of an inverse problem.A minimization problem is considered in which the time-history of the contact forceis sought such that the discrepancy between the predicted and the measured response(strains) is minimized. A particular feature of this formulation is that the discretization ofthe pertinent state equations in space-time, the sampling instances of the measurementsand the parameterization of the sought contact force are all independent of each other.Additionally, the convergence of the spatial and temporal discretization of the model andthe time parameterization of the contact force history are investigated.The proposed strategy is firstly evaluated for a simplified 2D disc with focus on the effectsof discretization, sensitivity to noise and possible improvements as a result of properregularization. Effects of considering different measurement outputs for the minimizationproblem are investigated. In particular, the identification strategy is modified by applyingvirtual calibration whereby an apparent static load is used as the measurement output,in order to compensate for model and spatial mesh sensitivity.Considering the realistic problem at hand, the rotating wheel is introduced and themeasured strains are combined using two Wheatstone bridges to estimate the contactforce by the static calibration technique. The inverse identification strategy is adoptedfor the designed measurement system. Effects of centrifugal and gyroscopic terms inthe equation of motion and consequences of noise in the measurement data are evaluated.Finally, the inverse identification strategy is compared to static calibration and a Kalmanfiltering technique for realistic load cases

Inverse Identification of Dynamic Wheel-rail Contact Forces

Accurate evaluation of contact forces between wheel and rail is essential in the assessment of vehicle performance and to predict consequences of dynamic vehicle-track interaction. As the contact forces can not be measured directly in the field, one common approach is to measure the strain or acceleration at various positions on a wheel or wheel axle. Based on this data, the forces can be estimated. However, the existing schemes typically involve either a simplified wheel model (neglecting inertia) or, in the case of using more advanced models, imply strong restrictions in terms of the choice of spatial and temporal discretization of the underlying equations of motion. In this work, the vertical contact force is determined by the solution of an inverse problem. A minimization problem is considered in which the time-history of the contact force is sought such that the discrepancy between the predicted and the measured response (strains) is minimized. A particular feature of this formulation is that the discretization of the pertinent state equations in space-time, the sampling instances of the measurements and the parameterization of the sought contact force are all independent of each other. Additionally, the convergence of the spatial and temporal discretization of the model and the time parameterization of the contact force history are investigated. The proposed strategy is firstly evaluated for a simplified 2D disc with focus on the effects of discretization, sensitivity to noise and possible improvements as a result of proper regularization. Effects of considering different measurement outputs for the minimization problem are investigated. In particular, the identification strategy is modified by applying virtual calibration whereby an apparent static load is used as the measurement output, in order to compensate for model and spatial mesh sensitivity. Considering the realistic problem at hand, the rotating wheel is introduced and the measured strains are combined using two Wheatstone bridges to estimate the contact force by the static calibration technique. The inverse identification strategy is adopted for the designed measurement system. Effects of centrifugal and gyroscopic terms in the equation of motion and consequences of noise in the measurement data are evaluated. Finally, the inverse identification strategy is compared to static calibration and a Kalman filtering technique for realistic load cases