General Recursion via Coinductive Types

A fertile field of research in theoretical computer science investigates the representation of general recursive functions in intensional type theories. Among the most successful approaches are: the use of wellfounded relations, implementation of operational semantics, formalization of domain theory, and inductive definition of domain predicates. Here, a different solution is proposed: exploiting coinductive types to model infinite computations. To every type A we associate a type of partial elements Partial(A), coinductively generated by two constructors: the first, return(a) just returns an element a:A; the second, step(x), adds a computation step to a recursive element x:Partial(A). We show how this simple device is sufficient to formalize all recursive functions between two given types. It allows the definition of fixed points of finitary, that is, continuous, operators. We will compare this approach to different ones from the literature. Finally, we mention that the formalization, with appropriate structural maps, defines a strong monad.Comment: 28 page

A Pilot Study Of The Prevalence Of Leg Pain Among Women With Endometriosis

Radiating leg pain is a common symptom presenting in manual therapy practices. Although this symptom has been reported as a complication of endometriosis, its prevalence and characteristics have not been studied. We surveyed members of a national endometriosis support group with endometriosis using a self-administered, mailed questionnaire. The main outcome measures were the prevalence and characteristics of leg pain. Of 94 respondents, leg pain was reported by 48 women (51%), and was bilateral in 59% of these symptomatic women. The likelihood of experiencing leg pain was related to weight gain since age 18, age, and height. The most common treatments tried included exercise, over-the-counter medications, and massage therapy, all with variable results. These data support leg pain as a prevalent complication of endometriosis, and that the disease may affect multiple peripheral nerves. Manual therapists should remain aware to this possible etiology for radiating pain

Caracterizacion del perfil clinico-epidemiologicos de los pacientes con diagnostico de Epilepsia registrados en la consulta externa del Hospital Infantil Manuel de Jesus Rivera en el periodo 1° de Enero 2013-31 de Diciembre 2014

La epilepsia es un trastorno neurológico crónico que afecta a personas de todas las edades, aún en nuestros días sigue siendo una enfermedad poco entendida aunque no por eso sea infrecuente como motivo de consulta, por lo que siempre ha sido necesario remarcarla como una de las prioridades a conocer. En Nicaragua existen pocos estudios relacionados con este tema, que describa el comportamiento clínico epidemiológico por lo que se desarrolló el presente estudio Descriptivo, retrospectivo, de corte transversal. El universo estuvo conformado por 1,366 niños y niñas con diagnóstico de epilepsia registrados en la consulta externa en el Hospital infantil Manuel de Jesús en el periodo Enero-Diciembre 2014-2015, obteniendo una muestra probabilística, para un total de 193 casos. El presente estudio reporta que la edad más frecuente fue el grupo de 1- 5 años, al igual que el sexo masculino, con residencia principalmente en el departamento de Managua, y presentando su primera crisis entre 1- 5 años de vida, en su mayoría sin ningún trastorno asociado. En general no se registraron antecedentes patológicos personales, y en el grupo que presentó, la asfixia perinatal fue el principal. Los antecedentes de epilepsia en la familia fueron negados. Las Epilepsias parciales fueron las más frecuentes, y dentro la subclasificación de ellas las complejas predominaron. El incumplimiento del tratamiento es el más relacionado a las crisis de Epilepsia. El cuanto al abordaje diagnóstico, el EEG es el principal medio diagnostico utilizado. En lo que respecta al manejo terapéutico, en la mayoría de los pacientes se utiliza la monoterapia, siendo el ácido valproico el principal fármaco. Se recomienda mejorar la descripción en los expedientes clínicos de las crisis de Epilepsia según la clasificación actual de la ILAE, crear conciencia de la necesidad de un manejo integral de las personas con epilepsia y desarrollar más estudios que nos permitan conocer mejor la evolución clínica de estos paciente

Termination Casts: A Flexible Approach to Termination with General Recursion

This paper proposes a type-and-effect system called Teqt, which distinguishes terminating terms and total functions from possibly diverging terms and partial functions, for a lambda calculus with general recursion and equality types. The central idea is to include a primitive type-form "Terminates t", expressing that term t is terminating; and then allow terms t to be coerced from possibly diverging to total, using a proof of Terminates t. We call such coercions termination casts, and show how to implement terminating recursion using them. For the meta-theory of the system, we describe a translation from Teqt to a logical theory of termination for general recursive, simply typed functions. Every typing judgment of Teqt is translated to a theorem expressing the appropriate termination property of the computational part of the Teqt term.Comment: In Proceedings PAR 2010, arXiv:1012.455

Ergodicity breaking in strong and network-forming glassy system

The temperature dependence of the non-ergodicity factor of vitreous GeO$_2$, $f_{q}(T)$, as deduced from elastic and quasi-elastic neutron scattering experiments, is analyzed. The data are collected in a wide range of temperatures from the glassy phase, up to the glass transition temperature, and well above into the undercooled liquid state. Notwithstanding the investigated system is classified as prototype of strong glass, it is found that the temperature- and the $q$-behavior of $f_{q}(T)$ follow some of the predictions of Mode Coupling Theory. The experimental data support the hypothesis of the existence of an ergodic to non-ergodic transition occurring also in network forming glassy systems

The ship model basin of Naples' University Federico II: Facilities, experimental tests, measurement systems

This work presents the main facilities of the Naples Towing Tank, LEIN: the instruments and the potential of the laboratory are presented, highlighting some strategies to resolve critical points typical of the towing tank tests. As example we point the attention on three aspects, typically critical: towing point of planing vessels, the accuracy of wave spectra generation and the settings of the radii of gyration for the seakeeping models

Bimanual coupling effect during a proprioceptive stimulation

Circle-line drawing paradigm is used to study bimanual coupling. In the standard paradigm, subjects are asked to draw circles with one hand and lines with the other hand; the influence of the concomitant tasks results in two "elliptical" figures. Here we tested whether proprioceptive information evoked by muscle vibration inducing a proprioceptive illusion (PI) of movement at central level, was able to affect the contralateral hand drawing circles or lines. A multisite 80 Hz-muscle vibration paradigm was used to induce the illusion of circle- and line-drawing on the right hand of 15 healthy participants. During muscle vibration, subjects had to draw a congruent or an incongruent figure with the left hand. The ovalization induced by PI was compared with Real and Motor Imagery conditions, which already have proved to induce bimanual coupling. We showed that the ovalization of a perceived circle over a line drawing during PI was comparable to that observed in Real and Motor Imagery condition. This finding indicates that PI can induce bimanual coupling, and proprioceptive information can influence the motor programs of the contralateral hand