Osteotomía valgizante de tibia: estudio de dos técnicas quirúrgicas

Se evalúan clínica y radiológicamente 51 rodillas artrósicas tratadas median - te osteotomía tibial valguizante según dos técnica s diferentes con fines comparativos. En 37 rodillas se empleó la osteotomía en cúpula con fijador externo y en las restante s se practicó la técnica en cuña de sustracción. El período de seguimiento medio fue de 42.2 meses. La suma de resultados buenos y excelente s ha sido 77.9%. La osteotomía en cúpula tiene , en esta serie, un mayor índice de pérdidas de corrección, correcciones insuficientes y complicaciones, obteniendo menor porcentaje de buenos resultados. Estos se deterioran en pacientes de mayor edad y gonartrosis evolucionada. Los autores consideran la osteotomía valguizante de tibia, un tratamiento válido par a pacientes de edad no avanzada y con gonartrosis grados I y II con genu varo.Two tecniques o f high tibia l osteotom y i n fifty-one ostheoarthiti c knee s evaluate d b y roentgenographi c an d clinica l examination . I n thirty-seve n patien s a dom e shape d osteotom y wit h externa l fixatio n wa s done . I n th e rest o f case s w e performe d a wedg e osteotomy . T h e numbe r o f goo d an d excelen t results wa s 77.9%. Th e dom e osteotom y ha s i n o u r experience , a hig h rat e o f recurren t varu s angulation , malalignemen t an d othe r complications. T h e olde r grou p o f patients ha d wors e results. Th e author s recomen d th e wedg e hig h tibia l osteotom y fo r osteoarthritis an d varu s kne e i n younge r patients

Imprevisión, una simple teoría

El presente artículo analizará y mostrará alternativas a la teoría de la imprevisión durante la actual crisis sanitaria surgida con ocasión de la pandemia del cóvid 19, ante las barreras que se suscitan a la hora de pretender su materialización y ante la flagrante transgresión a los principios de derecho privado que significarían la aplicación de esta teoría, como mecanismos más expeditos para el restablecimiento económico de un contrato cuando se ha alterado por circunstancias extraordinarias, imprevistas o imprevisibles, posteriores a la celebración y antes de la finalización del contrato, y que alteran desmedidamente el cumplimiento de las obligaciones a cargo de uno de los extremos contractuales. Con este propósito, y bajo una metodología hermenéutica analítica, se hará un recuento de la teoría de la imprevisión en la normatividad vigente y de los pronunciamientos jurisprudenciales relevantes al respecto, se analizará pormenorizadamente cada uno de los requisitos de esta institución, se abordarán las barreras que se suscitan al momento de su aplicación, se pondrá en evidencia por qué esta teoría es contraria a los principios de derecho privado y, finalmente, se mostrarán herramientas, diferentes a la revisión judicial del contrato, que cumplen el mismo propósito, de forma más práctica, expedita, y sin transgredir los principios de derecho privado.Universidad Libre -- Facultad de derecho -- Especialización en Derecho ComercialThis article will analyze and show alternatives to the theory of unpredictability during the current health crisis decreed on the occasion of Covid 19, given the difficulties that are succinct when trying to materialize it and the flagrant violation of the principles of law private, as more expeditious mechanisms for the economic reestablishment of a contract when it has been altered by extraordinary, unforeseen or unforeseeable circumstances, after the conclusion and before the end of it, which unduly alter the fulfillment of the obligations in charge of one of the contractual ends. With this purpose and under an analytical hermeneutical methodology, a recount will be made of the theory of unforeseen within the current regulations and the relevant jurisprudential pronouncements in this regard, each of the requirements of this institution will be analyzed in detail, the difficulties will be addressed that are succinct at the time of its application, it will become clear why this theory is contrary to the principles of private law, and finally it will show different tools to the judicial review of the contract that fulfill the same purpose, in a more practical way, expeditiously and without violating the principle of private rights

Factor analysis of Internet traffic destinations from similar source networks

This article is (©) Emerald Group Publishing and permission has been granted for this version to appear here (http://www.emeraldinsight.com/doi/full/10.1108/10662241211199951). Emerald does not grant permission for this article to be further copied/distributed or hosted elsewhere without the express permission from Emerald Group Publishing Limited.Purpose – This study aims to assess whether similar user populations in the Internet produce similar geographical traffic destination patterns on a per-country basis. Design/methodology/approach – We have collected a country-wide NetFlow trace, which encompasses the whole Spanish academic network, which comprises more than 350 institutions and one million users, during four months. Such trace comprises several similar campus networks in terms of population size and structure. To compare their behaviors, we propose a mixture model, which is primarily based on the Zipf-Mandelbrot power law to capture the heavy-tailed nature of the per-country traffic distribution. Then, factor analysis is performed to understand the relation between the response variable, number of bytes or packets per day, with dependent variables such as the source IP network, traffic direction, and country. Findings – Surprisingly, the results show that the geographical distribution is strongly dependent on the source IP network. Furthermore, even though there are thousands of users in a typical campus network, it turns out that the aggregation level which is required to observe a stable geographical pattern is even larger. Consequently, our results show a slow convergence rate to the domain of attraction of the model, specifically, we have found that at least 35 days worth of data are necessary to reach stability of the model’s estimated parameters. Practical implications – Based on these findings, conclusions drawn for one network cannot be directly extrapolated to different ones. Therefore, ISPs’ traffic measurement campaigns should include an extensive set of networks to cope with the space diversity, and also encompass a significant period of time due to the large transient time. Originality/value – Current state of the art includes some analysis of geographical patterns, but not comparisons between networks with similar populations. Such comparison can be useful for the design of Content Distribution Networks and the cost-optimization of peering agreements.This work has been partially funded by the Spanish Ministry of Education and Science under project ANFORA (TEC2009-13385), European Union CELTIC initiative program under project TRAMMS, European Union project OneLab, and the F.P.U. and F.P.I. Research Fellowship programs of Spain. The authors would also like to thank the anonymous reviewers who helped us to improve the quality of the paper

Influence of vertical movement in bathymetries and its influence on the measurement conditions

Bathymetries constitute a fundamental element of building objects settled on land submerged land: dikes, docks, underwater pipelines; in addition to dredges, volume of reservoir, etc. In civil engineering the bathymetry affect areas of small extent in which measures should be the most accurate as possible, influencing many factors in its precision. Among these factors can be distinguished: speed of sound in water, positioning system, vessel movements (pitch and roll) and vertical movement of the boat. Vertical movement of the vessel is perhaps one of the least studied factors, but their influence on the accuracy of bathymetries could be very important depending on swell conditions and depth that exists at the time of measurement. This paper defines a mathematical model based on measurements of bathymetry observed with GPS that lets you define wave conditions that found the boat according to its trajectory and speed. From this point, the article quantifies the effect of the vertical movement of the boat to correct its effect on the measured depths with an echo-sounder. Finally, from the results it is possible to obtain a set of recommendations about operations to measure a bathymetry depending on the accuracy that you should obtain

Determination of an empirical model for the deformation of a dam on the basis of the hydrostatic thrust and temperature

The deformational control of structures has its main exponent in the geometric control of large dams. Considering the constructive typology, they can suffer deformation, which is function of the hydrostatic thrust and the temperature that supports the dam under usual circumstances. The project designer usually calculates the deformation that the dam will suffer on the basis of thrust and temperature, but this calculation is theoretical, and it must be contrasted with the real data about deformation that are periodically observed in the dam, in order to certificate the adequate evolution of the structure through time. This research work is focused on the determination of an empirical model that allows the calculation of the deformation on the basis of the simultaneous observations of a direct pendulum that have been recorded with the correspondent temperatures during 14 years. This empirical model is later contrasted and validated with the records taken during the subsequent year. Although it is only valid for the dam where the tests were held (La Cohilla Dam, Cantabria, Spain), the methodology is suitable for any other structure. The main contribution of this research is the methodology itself, which allows obtaining an empirical model that determines the expected deformation, whatever the conditions of hydrostatic thrust and temperature are. It complements the theoretical model that the project designer has established, which is done just for a certain set of conditions of these variables

Bathymetries, history of an evolution in precision and performance

Bathymetries are a fundamental element in civil engineering when the work to be made must be based on the study of submerged terrain. In this sense, they are necessary in many situations: marine constructions such as dikes, docks, etc; dredging volume control, river flood study, etc. Traditionally bathymetries have been a difficult and costly job both in time and effort. However, over time and supported by the development of topographic and geodetic technologies, they have undergone an important transformation and progress in both precision and performance. In this sense, this article reviews the evolution of the different topographic techniques used over time, emphasizing the investigation and study of the accuracies and efficiencies typical of them; especially those that are used today. In this way, it can be concluded that, with the appropriate methodology, currently, bathymetries can be made with centimeter accuracy and with an efficiency that can exceed several square kilometers each day depending on the desired accuracy and the conditions of the bottom to be measured

Quantitative contrast between the methodologies for the volumetric evaluation with cross-sections and 3D models in tunnels excavated with explosives

This research aims to establish the differences that are produced when calculating the volume of the excavation of a tunnel by means of equidistant cross sections obtained from a 3D model, and the 3D model itself, which was obtained from laser scanner data. The purpose of this research intends to contrast numerically a methodology that has been traditionally applied (cross-sections), and a more recent one which is supported by the use of powerful calculation algorithms that are appropriate for 3D models. All this research is applied to a tunnel that is used as spillway of a large dam that serves to regulate the water of a hydraulic facility. The results of this work justify in a quantitative way that, compared to the modern approach, the classical methodology produces deviations that can reach the 10% of the total volume of the excavation, which implies very high expenses, given the costs of this kind of work

Skyrmion motion induced by voltage-controlled in-plane strain gradients

[EN] Micromagnetic simulations are used to investigate the motion of magnetic skyrmions in an in-plane strain gradient. The skyrmion diameter and energy are found to depend on the strain, which leads to a force that moves the skyrmion toward regions with higher strain. An analytical expression for the skyrmion velocity as a function of the strain gradient is derived assuming a rigid profile for the skyrmion, and good agreement with simulations is obtained. Furthermore, electromechanical simulations of a hybrid ferromagnetic/piezoelectric device show that the in-plane strain gradients needed to move skyrmions can be achievedProject No. MAT2017-87072-C4-1-P from the (Ministerio de Economía y Competitividad) Spanish government Project No. SA299P18 from Consejería de Educacíon Junta de Castilla y León