Design and optimization of the graft pretension protocol for the reconstruction of the anterior cruciate ligament (ACL)

Anterior cruciate ligament (ACL) rupture is one of the mayor concerns of today’s professional high demand athletes due to its high probabilities of happening and slow recovery. In general, the grafts used in ACL reconstruction surgeries are tendons taken from the same patient in order to reduce the possibility of rejection. However, these soft tissue grafts share viscoelastic properties which produce an elongation of the graft after its implantation, which if too much can lead to an invalid surgery. Thus, in order to eliminate this undesired property, the tendon needs to be preconditioned after its removal from the patient and before the re-implantation. This procedure involves a graft board to be able to apply a specific load to the tendon, thus being able to elongate it before its final implantation in the affected person. However, this protocol has not been standardized to date, hence each surgeon proceeds in their own way. The main goal of this project is to design and optimize a graft pretension protocol for the reconstruction of the anterior cruciate ligament. Digital Extensor Bovine tendons were used in order to test the quality and efficiency of the proposed protocols. Using a hydraulic machine, an ACL reconstruction surgery was simulated. A successful surgical procedure is determined by the graft elongation after its implantation in the knee, which if elongated too much invalids the reconstruction, not being able to achieve the natural ACL functions. Thus, out of all the parameters obtained, the most important one and so, taken into account for the discussion, is the elongation of the graft in the rehabilitation process. Using this parameter, protocols can be compared. Two out of the three protocols proposed show to be statistical different from the control group. The third one produced a high elongation of the tendon grafts due to the small value load applied to them. As no significant difference was found between the two successful protocols, we can determine that the one implying less load would be the best one for its reproducibility in the operating room. In conclusion, a pretension protocol is beneficial to the grafts as it reduces post-surgery elongation and it has to consist of at least 89 N in order to be able to eliminate part of the graft’s intrinsic viscoelastic properties.Ingeniería Biomédica (Plan 2010

Identidad sin sujeto: Arendt y el mutuo reconocimiento

This article discusses whether, from Hannah Arendt’s point of view, the being-in-common of singularities can be conceived in terms of mutual recognition. Although it is shown that Arendt’s theory of action involves the idea that the identity of singularities is relational, it is also stressed that it is a fluid identity, thrown into contingency. Therefore, it is not a more solid self consciousness what individuals achieve when they open themselves to each other and when they recognize themselves in their difference. What they achieve is to be exposed to the fact of coexistence, to an experience of plurality in which others are more than just a mirror in which they recognize and affirm themselves

Estimating non-linear models with multiple fixed effects : a computational note

En este trabajo se estudia la estimación de modelos no lineales de datos de panel que incluyen efectos fijos múltiples. La estimación de estos modelos es complicada tanto por la dificultad de estimar especificaciones con miles de coeficientes, como por el problema de los parámetros incidentales, esto es, cuando la dimensión temporal del panel es corta la imprecisión en la estimación de los efectos individuales contamina la de los parámetros comunes debido a la no linealidad del modelo. En el artículo se propone una variación simple de los estimadores de verosimilitudes corregidas de sesgo, que permite explotar la aditividad de los efectos en la optimización numérica, evitando así el cálculo de los efectos estimados para valores dados de los parámetros comunes. Simulaciones muestran el rendimiento del estimador propuest

Modelling heterogeneity and dynamics in the volatility of individual wages

Incluye bibliografíaIn this paper I consider a model for the heterogeneity and dynamics of the conditional mean and the conditional variance of standarized individual wages. In particular, I propose a dynamic panel data model with individual effects both in the mean and in a conditional ARCH type variance function. I posit a distribution for earning shocks and I build a modified likelihood function for estimation and inference in a fixed-T context. Using a newly developed bias-corrected likelihood approach makes it possible to reduce the estimation bias to a term of order 1 over T squared. The small sample performance of bias corrected estimators is investigated in a Monte Carlo simulation study. The simulation results show that the bias of the maximum likelihood estimator is substantially corrected for designs that are broadly calibrated to the PSID. The empirical analysis is conducted on data drawn from the 1968-1993 PSID. I find that it is important to account for individual unobserved heterogeneity and dynamics in the variance, and that the latter is driven by job mobility. I also find that the model explains the non-normality observed in logwage dat

The cycle of earnings inequality : evidence from Spanish Social Security data

We use detailed information on labor earnings and employment from Social Security records to document earnings inequality in Spain from 1988 to 2010. Male earnings inequality was strongly countercyclical: it increased around the 1993 recession, showed a substantial decrease during the 1997-2007 expansion and then a sharp increase during the recent recession. These developments were partly driven by the cyclicality of employment and earnings in the lower-middle part of the distribution. We emphasize the importance of the housing boom and subsequent housing bust, and show that demand shocks in the construction sector signifi cantly impacted aggregate labor market outcomesEn este trabajo se utiliza información detallada de ingresos salariales y empleo procedente de registros de la Seguridad Social para documentar la evolución de la desigualdad salarial en España desde 1988 a 2010. La desigualdad salarial para los hombres ha sido fuertemente contracíclica: aumentó alrededor de la recesión de 1993, mostró un descenso sustancial en el período de expansión de 1997 a 2007 y evidenció un marcado incremento durante la crisis reciente. Esta evolución se ha debido, en parte, a la evolución cíclica del empleo y de los salarios en la parte baja-media de la distribución salarial. Enfatizamos la importancia del boom de la construcción y su posterior caída, y mostramos que los shocks de demanda en este sector han tenido efectos signifi cativos sobre variables agregadas del mercado laboral españo

Más allá de algunos lugares comunes: Repensar la potencia política del pensamiento de Jacques Rancière

In current discussions on contemporary political philosophy some commonplaces around Rancière’s thought are restated with the effect of neutralizing the potential of his reflections. I refer in particular to the following assumptions: a dichotomic understanding of Rancière’s distinction between politics and the police, an ontological interpretation of this difference, an identification of Rancière’s political propositions as anti-institutionalist; a reading of the practices of emancipation as something ephemeral without a durable effect for the common world. In this article I question these assumptions by emphasizing some usually neglected aspects of Rancière’s arguments.En discusiones sobre filosofía política contemporánea se reiteran una serie de lugares comunes en torno al pensamiento de Rancière que neutralizan la potencia de sus apuestas. Me refiero, en particular, a una comprensión dicotómica de la distinción rancieriana entre policía y política; a una interpretación ontológica de esta diferencia; a una identificación de las reflexiones políticas de Rancière como anti-institucionalistas; y a una lectura de las prácticas de emancipación como si se tratara de algo efímero, sin algún efecto perdurable para el mundo común. En este artículo cuestiono estas lecturas haciendo valer una serie de aspectos significativos de los planteamientos de Rancière, que se pierden de vista en aquellas

Hobbesian Moral and Political Theory.

Aunque la publicación de este libro data de algunos años, las tesis que allí se defienden siguen estando presentes en las discusiones académicas sobre filosofía hobbesiana y, en general, sobre filosofía política. Así se realiza, en parte, la pretensión que el autor anuncia en el prefacio del texto: introducir a Hobbes en la lista de pensadores selectos en el debate sobre filosofía moral y política, integrada por Kant, Locke, Marx y los utilitaristas clásicos. En esa medida, de acuerdo con las..

Lágrimas de felicidad tras aprobación, en el Senado, de tres causales de proyecto que despenaliza el aborto

La sala del Senado de Chile aprobó, las tres causales del proyecto de ley que despenaliza la interrupción del embarazo en tres causales: riesgo de vida materna, inviabilidad fatal y violación.http://www.elmostrador.cl/braga/2017/07/19/lagrimas-de-felicidad-tras-aprobacion-de-proyecto-que-despenaliza-el-aborto-en-tres-causales/?utm_source=La+Pauta+de+El+Mostrado

Retirement patterns of couples in Europe

En este trabajo analizamos las pautas de jubilación de parejas en el contexto europeo utilizando datos de la Survey of Health, Aging and Retirement in Europe (SHARE). En concreto, evaluamos si las salidas del mercado de trabajo de las mujeres (hombres) están causadas por el hecho de que sus maridos (mujeres) dejen de trabajar, usando la variación institucional en las edades oficiales de jubilación (anticipada y normal) específicas de cada país como instrumento. Explotando las discontinuidades en los incentivos a la jubilación de cada país, encontramos que la jubilación de los maridos tiene un efecto significativo de entre 16 y 18 puntos porcentuales en la probabilidad de dejar de trabajar de sus mujeres. Para los hombres el efecto es similar en magnitud, pero no es estadísticamente significativo. Este efecto indirecto de la jubilación conjunta puede tener importantes consecuencias para la implementación de reformasIn this paper we study the retirement patterns of couples in a multi-country setting using data from the Survey of Health, Aging and Retirement in Europe. In particular, we test whether women’s (men’s) transitions out of the labor force are causally related to the actual realization of their husbands’ (wives’) transition, using the institutional variation in country-specific early and full statutory retirement ages to instrument the latter. Exploiting the discontinuities in retirement behavior across countries, we find a significant joint retirement effect, especially for women, of around 16 to 18 percentage points. For men, we find a similar but less precise effect. Our empirical strategy allows us to give a causal interpretation to the effect we estimate. In addition, this effect has important implications for policy analysi