Liquid-liquid phase transitions and water-like anomalies in liquids

In this thesis we employ computer simulations and statistical physics to understand the origin of liquid-liquid phase transitions and their relationship with anomalies typical of liquid water. Compared with other liquids, water has many anomalies. For example the density anomaly: when water is cooled below 4 C the density decreases rather than increases. This and other anomalies have also been found to occur in a few other one-component liquids, sometimes in conjunction with the existence of a liquid-liquid phase transition (LLPT) between a low-density liquid (LDL) and a high-density liquid (HDL). Using simple models we explain how these anomalies arise from the presence of two competing length scales. As a specific example we investigate the cut ramp potential, where we show the importance of "competition" in this context, and how one length scale can sometimes be zero. When there is a clear energetic preference for either LDL or HDL for all pressures and temperatures, then there is insufficient competition between the two liquid structures and no anomalies occur. From the simple models it also follows that anomalies can occur without the presence of a LLPT and vice versa. It remains therefore unclear if water has a LLPT that ends in a liquid-liquid critical point (LLCP), a hypothesis that was first proposed based on simulations of the ST2 water model. We confirm the existence of a LLCP in this model using finite size scaling and the Challa-Landau-Binder parameter, and show that the LLPT is not a liquid-crystal transition, as has recently been suggested. Previous research has indicated the possible existence of a LLCP in liquid silica. We perform a detailed analysis of two different silica models (WAC and BKS) at temperatures much lower than was previously simulated. Within the accessible temperature range we find no LLCP in either model, although in the case of WAC potential it is closely approached. We compare our results with those obtained for other tetrahedral liquids and conclude that insufficient "stiffness" in the Si-O-Si bond angle might be responsible for the absence of a LLCP

Pedagogía y derecho

Ni los juristas ni las pedagogías tienden a cruzar las relaciones existentes entre Derecho y Pedagogía tan extensamente como deberían. El Dr. Lascaris estudia su mutua implicación señalando históricamente su superposición constante. La historia de la ley está interesada en las instituciones educativas desde el punto de vista de su regulación jurídica; la pedagogía debe tener en cuenta el Derecho administrativo y administrativo tanto por la repercusión que las concepciones jurídicas tienen en la educación como por la necesidad de conocer la ley regulación de sus propias instituciones. Por otro lado, la Ley tiene su valor educativo en la medida en que enseña a los críticos a no hacer algunas acciones: ese es el valor educativo del castigo. Este valor educativo debe ser complementado por una educación cívica y una enseñanza jurídica que impliquen a todos los hombres a una aceptación consciente de la Ley

Origen del término pedagogía

Antes de definir un concepto es procedimiento aconsejado, según la hermenéutica analítica, el delimitar su valor etimológico y su posible evolución semántica . No pretendo hacer aquí su historia completa , para la cual me remito a los Diccionarios básicos, sino tan solo señalar sus hitos principales que nos puedan servir después como lugares de referencia en nuestro estudio . Pedagogía es una palabra griega . No culta inventada sobre raíces griegas, sino con vida propia en el griego , no solo en el moderno, sino en el clásico

La intransmisibilidad del saber

Sea cual sea la definición de enseñanza que se dé, siempre se comprenderá en ella una relación entre educando y educador, y, fruto de esta relación, se da el «incremento» el «saber» en educando . Si se prescinde de la enseñanza y se toma el caso (hoy utópico) de la total autoformación, se encontraría que es el individuo mismo, uno solo, el que elabora todas sus conocimientos, sin ayuda ajena . Así se ve que en el caso del Autodidacto, de Aben Tofail, es el solitario quien, por el empleo de su sola inteligencia y por la contemplación de la naturaleza, forja toda la filosofía; pero en este caso (que, por lo demás, no pretende afirmar la posibilidad real de su desarrollo, sino que atiende al proceso .dialéctico de la constitución de la ciencia) no pasa de ser una pura especulación . Y así, si se fija la atención, como pura ejemplificación, en otros dos modelos de esta autoformación, veremos que el pensador ( ?) no ha osado plantear la cuestión con tal radicalidad

Vluchtschansen in Midden-Limburg. Boerenschansen uit de 16de en 17de eeuw als schuilplaatsen voor de plattelandsbevolking

In the southern provinces of the Netherlands and the neighbouring parts of Belgium traces have been discovered of an interesting group of 'farmers' entrenchments', small fortifications from the Early Modern Period. Between the sixteenth and eighteenth century, a period of frequent warfare. many villages and hamlets built simple fortifications as refuges for the population and their cattle. Some of these refuges were located close to the villages, other examples were  built in less accessible terrains such as stream valleys. In this article, an inventory of these small fortifications for one of the core regions, the central part of the Dutch province of Limburg, is presented. Two examples are studied in some more detail: the refuges of Boshoven and Laar (municipality of Weert). At Boshoven, part of the archive still exists. This object is remarkable, as the oldest cadastral map (c.1830) still shows how every inhabitant of the village owned a tiny plot within the refuge. At Laar, a small archaeological survey was executed. following a request from the village for input for a planned restoration project

Normothermic liver machine perfusion as a dynamic platform for regenerative purposes. What does the future have in store for us?

Liver transplantation has become an immense success; nevertheless, far more recipients are registered on waiting lists than there are available donor livers for transplantation. High-risk, extended criteria donor livers are increasingly used to reduce the discrepancy between organ demand and supply. Especially for high-risk livers, dynamic preservation using machine perfusion can decrease post-transplantation complications and may increase donor liver utilization by resuscitation and viability testing before transplantation. To further increase the availability of donor livers suitable for transplantation, new strategies are required that make it possible to use organs that are initially too damaged to be transplanted. With the current progress in experimental liver transplantation research, (long-term) normothermic machine perfusion may be used in the future as a dynamic platform for regenerative medicine approaches, enabling repair and regeneration of injured donor livers. Currently explored therapeutics such as defatting cocktails, ribonucleic acid interference, senolytics, and stem cell therapy may assist in the repair and/or regeneration of injured livers before transplantation. This review will provide a forecast of the future utility of normothermic machine perfusion for repair and regeneration of damaged donor livers to ultimately decrease the imbalance between donor liver demand and supply

Pedagogía del arte

La inusitada proliferación de la Pedagogía en los últimos cien años y su ambigüedad esencial, han nevado a replantear la temática del nombre (siempre sobre las perennes coordenadas del pensamiento helénico, pues todavía no ha inventado la humanidad moderna otra forma de pensar), con la perspectiva de un dinamismo que unas veces se ofrece como pragmático y otras como histórico. En cambio, el Arte siempre ha constituido un hacer del hombre, y la Pedagogía del Arte es algo ordinariamente concebible cuando el hombre no es capaz de tal hacer, o, al menos, va dirigida a quienes no se muestran capaces de tal hacer

Super-paramagnetic clustering of yeast gene expression profiles

High-density DNA arrays, used to monitor gene expression at a genomic scale, have produced vast amounts of information which require the development of efficient computational methods to analyze them. The important first step is to extract the fundamental patterns of gene expression inherent in the data. This paper describes the application of a novel clustering algorithm, Super-Paramagnetic Clustering (SPC) to analysis of gene expression profiles that were generated recently during a study of the yeast cell cycle. SPC was used to organize genes into biologically relevant clusters that are suggestive for their co-regulation. Some of the advantages of SPC are its robustness against noise and initialization, a clear signature of cluster formation and splitting, and an unsupervised self-organized determination of the number of clusters at each resolution. Our analysis revealed interesting correlated behavior of several groups of genes which has not been previously identified