891 research outputs found

    Indexed induction and coinduction, fibrationally.

    Get PDF
    This paper extends the fibrational approach to induction and coinduction pioneered by Hermida and Jacobs, and developed by the current authors, in two key directions. First, we present a sound coinduction rule for any data type arising as the final coalgebra of a functor, thus relaxing Hermida and Jacobs’ restriction to polynomial data types. For this we introduce the notion of a quotient category with equality (QCE), which both abstracts the standard notion of a fibration of relations constructed from a given fibration, and plays a role in the theory of coinduction dual to that of a comprehension category with unit (CCU) in the theory of induction. Second, we show that indexed inductive and coinductive types also admit sound induction and coinduction rules. Indexed data types often arise as initial algebras and final coalgebras of functors on slice categories, so our key technical results give sufficent conditions under which we can construct, from a CCU (QCE) U : E -> B, a fibration with base B/I that models indexing by I and is also a CCU (QCE)

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

    Get PDF
    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

    Fibrational induction meets effects

    Get PDF
    This paper provides several induction rules that can be used to prove properties of effectful data types. Our results are semantic in nature and build upon Hermida and Jacobs’ fibrational formulation of induction for polynomial data types and its extension to all inductive data types by Ghani, Johann, and Fumex. An effectful data type μ(TF) is built from a functor F that describes data, and a monad T that computes effects. Our main contribution is to derive induction rules that are generic over all functors F and monads T such that μ(TF) exists. Along the way, we also derive a principle of definition by structural recursion for effectful data types that is similarly generic. Our induction rule is also generic over the kinds of properties to be proved: like the work on which we build, we work in a general fibrational setting and so can accommodate very general notions of properties, rather than just those of particular syntactic forms. We give examples exploiting the generality of our results, and show how our results specialize to those in the literature, particularly those of Filinski and Støvring

    Hidatidosis ósea: nuestra casuística

    Get PDF
    Se revisan los resultados de 16 casos de hidatidosis musculoesquelética tratados en la Unidad de Sépticos del Aparato Locomotor del Hospital Universitario "La Fe" de Valencia en el período 1972-1989. Las dificultades diagnósticas fueron importantes, siendo en 5 de los casos un diagnóstico operatorio. Analizados los métodos de tratamiento se llega a la conclusión de que la curación definitiva sólo se consigue con la resección completa y amplia de la lesión. Los curetajes, acompañados o no de aseptizaciones químicas, suelen dar recidivas. Se recomienda combinar el tratamiento médico con el quirúrgico.The results of 16 cases of musculoskeletal hydatidosis treated in the locomotive Apparatus Septic Unit of the Valencia University Hospital "La Fe" between 1972 and 1989 wer e reviewed. The diagnostic difficulties wer e marked and 5 cases wer e diagnosed at surgery. After analyzing the therapeutical approaches, it is drawn the conclusion that a definitive healing is achieved only when an extensive and complete resection is done. Curettage, with and without chemical aseptization, generally results in recurrence. A combined medical and surgical treatment is recommended

    A Direct Real-Time Observation of Anion Intercalation in Graphite Process and Its Fully Reversibility by SAXS/WAXS Techniques

    Get PDF
    The process of anion intercalation in graphite and its reversibility plays a crucial role in the next generation energy-storage devices. Herein the reaction mechanism of the aluminum graphite dual ion cell by operando X-ray scattering from small angles to wide angles is investigated. The staging behavior of the graphite intercalation compound (GIC) formation, its phase transitions, and its reversible process are observed for the first time by directly measuring the repeated intercalation distance, along with the microporosity of the cathode graphite. The investigation demonstrates complete reversibility of the electrochemical intercalation process, alongside nano- and micro-structural reorganization of natural graphite induced by intercalation. This work represents a new insight into thermodynamic aspects taking place during intermediate phase transitions in the GIC formation
    corecore