981 research outputs found

    A bifibrational reconstruction of Lawvere's presheaf hyperdoctrine

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    Combining insights from the study of type refinement systems and of monoidal closed chiralities, we show how to reconstruct Lawvere's hyperdoctrine of presheaves using a full and faithful embedding into a monoidal closed bifibration living now over the compact closed category of small categories and distributors. Besides revealing dualities which are not immediately apparent in the traditional presentation of the presheaf hyperdoctrine, this reconstruction leads us to an axiomatic treatment of directed equality predicates (modelled by hom presheaves), realizing a vision initially set out by Lawvere (1970). It also leads to a simple calculus of string diagrams (representing presheaves) that is highly reminiscent of C. S. Peirce's existential graphs for predicate logic, refining an earlier interpretation of existential graphs in terms of Boolean hyperdoctrines by Brady and Trimble. Finally, we illustrate how this work extends to a bifibrational setting a number of fundamental ideas of linear logic.Comment: Identical to the final version of the paper as appears in proceedings of LICS 2016, formatted for on-screen readin

    Fijación externa en las fracturas-luxaciones centrales de cadera: a propósito de 3 casos

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    Se presentan tres casos de fractura-luxación central de cadera tratados mediante estabilización y reducción progresiva con fijación externa. Las ventajas de este tratamiento con respecto al tratamiento conservador o quirúrgico son la estabilización inmediata y la sencillez de realización. Los resultados de fijación externa obtenidos en estos pacientes demuestran una rehabilitación y deambulación precoz e independiente. La recuperación clínica y funcional fue satisfactoria en dos casos. En otro caso, con mala reducción quirúrgica previa, el resultado fue pobre.Three cases of central fracture-dislocation of the hip treated by stabilization and progressive reduction by means of external fixation are presented. The advantages of this procedure over the conservative or even the surgical treatment are the early stabilization and the fact that the technique is a step-forward procedure. The results obtained in these patients with external fixation of the hip led to a good rehabilitation and to an early independent ambulation. The clinical and functional recovery of these patients was satisfactory in two cases. In other with previous failed open reduction the result was poor

    Pseudosubluxación C2-C3: un hallazgo radiológico frecuente en la infancia

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    Objetivo: Mostrar un hallazgo radiológico fisiológico de la columna cervical infantil que tiende a ser malinterpretado como patológico: la pseudosubluxación C2-C3. Se presenta un caso de una niña de 14 meses de edad remitida a nuestro centro bajo sospecha de subluxación C2-C3. Se aporta una metodología para el diagnóstico diferencial entre pseudosubluxación C2-C3 y subluxación C2-C3 verdadera. Una anamnesis detallada así como una exploración clínica y radiográfica minuciosas, permiten establecer el diagnóstico en la mayoría de los casos. La normal movilidad en flexión de C2 sobre C3 en la columna cervical infantil puede ser tan pronunciada que llegue a confundirse con una lesión. La interpretación adecuada de las radiografías simples de la columna cervical en los niños requiere el conocimiento de las peculiaridades de este segmento en la edad pediátrica.Objective: To report on a physiological radiographic finding of the cervical spine in childhood that trends to be misjudged as pathologic: C2-C3 pseudosubluxation. We presented a girl, aged 14 months, who was remitted to our Center for clinical suspect of C2-C3 subluxation. A diagnostic methodology is offered to distinguish between C2-C3 pseudosubluxation and a true C2-C3 subluxation. A detailed anamnesis as well as a meticulous radiological and clinical exploration, allow to establish the right diagnosis in most cases, without any other complementary probe. The normal mobility of C2 on C3 in flexion could be so pronounced as to be mistaken for a pathological finding. The suitable radiographic interpretation of the cervical spine in children requires the knowledge of the peculiarities of this segment in the pediatric age

    Tratamiento quirúrgico de la escoliosis en el síndrome de Rett: sistema de instrumentación TRANSPINE

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    El Síndrome de Rett es una afectación neurológica que en los estadios últimos presenta deformidades evolutivas que suelen precisar cirugía. Se han revisado en este estudio 11 pacientes con Síndrome de Rett y deformidad en columna que precisaron cirugía. Se analizaron las magnitudes de las curvas con ángulo de Cobb, alteraciones del plano sagital (cifosis y lordosis), oblicuidad pélvica pre y postoperatoria, niveles de fusión y complicaciones postoperatorias. La corrección media fue del 65%. Se realizó una fusión posterior en todos los pacientes sin incluir sacro pelvis. Los montajes se realizaron principalmente con sistema híbrido de tornillos, ganchos, pinzas y cables laminares TRANSPINE®. Las escoliosis neuromusculares, como el síndrome de Rett, que precisan corrección, pueden controlarse de forma segura y efectiva mediante artrodesis posterior con instrumentación híbrida.Rett Syndrome is a neurological impairment with a typically long C scoliosis curve that often require surgery. In this study it has been reviewed 11 patients with Rett syndrome and spine deformity. We analyzed the magnitudes of the curves with Cobb angle, sagittal plane (kyphosis and lordosis), preoperative and postoperative pelvic obliquity, fusion levels and postoperative complications. The average correction was 65%. Posterior fusion was performed in all patients excluding sacrum pelvis. The assemblies are made mainly with the hybrid system of screws, hooks, clips and cables TRANSPINE®. Neuromuscular scoliosis, such as Rett syndrome, which needs correction, can be controlled safely and effectively by posterior fusion with hybrid constructs

    Mesoporous Functionalized Acid Catalysts And Their Use As Environmentally Friendly Catalysts In Esterification Of Glycerols For Monoglyceride Production.

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    Monoglycerides are valuable compounds with wide applications as emulsifiers in food, pharmaceutical and cosmetic industries. They can be produced by esterification of glycerols with fatty acids

    Methodology for characterization, evaluation and optimization of acoustic environments

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    Currently we are working on methodologies to characterize, evaluate and optimize acoustic environments with different approaches. One methodology is based on the evaluation of temporal energetic behavior of acoustic environment through the use of parameters associated with the autocorrelation function (ACF). In this case the main objective is to verify the variability of the temporal behavior of urban acoustic environment depending of sounds sources that are part of them. We evaluate the temporal energetic behavior in 10 urban acoustic environments using ACF in two main cities, Brasilia (Brazil) and Bogotá (Colombia). The second methodology is based on the design of an experiment to improve and optimize acoustic environments on the basis of the auditory subjective experiences of the people. It has been designed a LabVIEW application for psychoacoustic laboratory tests to evaluate the subjective perception of people. The main objective is to evaluate how adding sound signals in acoustics environments with traffic noise couls improve the experience of the users

    Toracoplastia expansiva en el tratamiento de la escoliosis congénita torácica con malformaciones vertebrales asociadas a fusión costal

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    Se presenta el caso clínico de un paciente varón de 3 años de edad con escoliosis congénita torácica en el contexto de un síndrome de VACTERL, que presentaba defectos múltiples de segmentación vertebral con fusión costal asociada, en el que se realizó una toracoplastia expansiva mediante un sistema protésico vertical expandible de titanio de distracción costal, consiguiéndose una corrección indirecta de la escoliosis, favoreciendo el desarrollo torácico y pulmonar en la concavidad de la curva, y retrasando la instrumentación con fusión vertebral.This paper reports on a 3-year-old patient with congenital thoracic scoliosis in the context of a VACTERL's syndrome, who had many spinal segmental defects with ribs fusion associated, in which an expansion thoracoplasty was made by means of a vertical expandable prosthetic titanium rib. An indirect correction of the scoliosis was achieved allowing the thoracic and respiratory development in the concavity of the curve and, thus, postposing the instrumentation with spinal fusion
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