Crisis en la Historia: revisiones y perspectivas

Se cuestiona el concepto de crisis historiográfica, que habría surgido del abandono del paradigma estructuralista de los años sesenta y setenta. Ese esquema sólo se dio en una minoría de estudios. La mayor parte tuvo como principio (inicio y fundamento) el análisis documental que desborda y quiebra todo modelo. En historia rigen obras ejemplares que originan dinastías de trabajos delimitados por temas, enfoques y usos conceptuales. La evolución es lenta, con pequeñas crisis en pequeños paradigmas. La crisis (en singular) es una noción ideológica que corresponde a luchas por el predominio de algunos conjuntos. El micro medio tiene importancia en esto; la situación política es el escenario coyuntural de ese desarrollo. Para finalizar, se propone vincular la historia con la gran tradición filosófica consagrada a la doctrina del ser.The concept of historiographic crisis, which would have arisen from the abandonment of the structuralist paradigm prevailing in the sixties and seventies, is questioned in this paper. This scheme was true only in a few studies. The beginning and foundation of most of them was the documentary analysis which overflows and breaks every model. In history, there are exemplary works which give rise to dynasties of works delimited by conceptual subjects, approaches and uses. The evolution is slow, with small crises in small paradigms. Crisis is an ideological notion related to the struggles for the predominance of some groups. The micro medium is important in this; the political situation is the stage for such development. To conclude, we propose to link history to the great philosophical tradition devoted to the doctrine of being

Risks and opportunities in arbitrage and market-making in blockchain-based currency markets. Part 1 : Risks

This study provides a practical introduction to high-frequency trading in blockchain-based currency markets. These types of markets have some specific characteristics that differentiate them from the stock markets, such as a large number of trading exchanges (centralized and decentralized), relative simplicity in moving funds from one exchange to another, and the large number of new currencies that have very little liquidity. This study analyzes the possible risks that specifically characterize this type of trading operation, the potential opportunities, and the algorithms that are mostly used, providing information that can be useful for practitioners who intend to operate in these markets by providing (and risking) liquidity

Unequal peasant struggles in the Middle Ages and lessons for the historian in the comparison documentary

Entre 1110 y 1116 se desarrolló una gran insurrección campesina en la zona leonesa, la cual acompañó a la rebelión que en esos años protagonizaron los burgueses de Sahagún. En esa lucha participaron campesinos de Grajal. Se compara esa sublevación con un conflicto que los pobladores de ese concejo sostuvieron posteriormente con el monasterio de Sahagún, en torno al uso de las aguas del Cea. Se analiza así una lucha local, se observan las divisiones internas del campesinado y el papel de sus líderes encauzando las demandas. Con el análisis comparado se establecen las barreras que el campesino debió superar para conseguir la unidad de acción que se dio en el alzamiento regional de principios del siglo XII.Between 1110 and 1116 developed a great peasant insurrection in Leonesa area, which accompanied the rebellion that in those years staged the Sahagun burghers. In this struggle the Grajal peasant took part. This uprising is compared with a conflict that the people of the local council argued subsequently with the Sahagun monastery, surrounding the use of the Cea´s waters. It is analyzed as well a local struggle there are the internal divisions of the peasantry and the role of its leaders by channelling the demands. The analysis compared with laying down the barriers that the peasant had to overcome to achieve the unity of action that was regional in the uprising of the early twelfth century.Fil: Astarita, Carlos Alberto Tomas. Universidad de Buenos Aires; Argentina. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

3D reconstruction of the flow and vortical field in a rotating sharp "U” turn channel

Particle image velocimetry experiments have been carried out to obtain visualizations and measurements of the main and secondary flow fields in a square channel with a sharp "U” turn. Both the main and the secondary flow fields have been used to perform a 3D reconstruction of the mean flow and vortical fields in the turn region and in the outlet duct. In order to study the influence of the rotation, tests both in stationary (absence of rotation, Re=20,000) and in rotating (Re=20,000 and Ro=0.3) conditions have been performed. The results show that the Coriolis and centrifugal forces, caused by the rotation, yield strong modifications to the symmetrical flow and vortical fields that are generated, in the static case, only by the abrupt inversion of the flow directio

Herejías e identidades en un conflicto de España en el siglo XII

En la rebelión del burgo Sahagún de 1110-1116, que se extendió al campesinado de un extenso territorio circundante, encontramos tres cuestiones superpuestas: a) el enfrentamiento entre los burgueses y el abad; b) la persecución a los mozárabes; c) el estallido antisemita del campesinado. Aquí se examinarán estas cuestiones por separado para mostrar que cada una representó una problemática especial y motivó resoluciones represivas peculiaresIn the rebellion of the Sahagún burgo in 1110-1116, extended to peasantry of an extensive territory that surrounds it, we find three overlapping issues: a) the confrontation between the bourgeois and the abad; b) the persecution to the mozarabes; c) the anti-semitic outbreak of the peasantry. These issues should be considered independently, to show each represented a special problem and motivated peculiar repressive resolutions.Fil: Astarita, Carlos Alberto Tomas. Universidad de Buenos Aires. Facultad de Filosofia y Letras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones en Humanidades y Ciencias Sociales; Argentina. Universidad Nacional de La Plata; Argentin

Desarrollo institucional en dos áreas del sistema feudal

En el presente estudio se comparan los fundamentos institucionales de dos áreas del sistema feudal, entre los siglos IX y XII. Una de ellas, León y Castilla al norte del Duero, corresponde al centro del feudalismo, y se asemeja en sus características y cronología esenciales a Francia entre el Loire al Rin, al centro norte de Italia, Flandes, sur este de Inglaterra y norte de la región catalano aragonesa. Se trata del área nuclear del sistema1. La otra, al sur del Duero, es la Extremadura Histórica, que abarca desde este río al Sistema Central, y se corresponde con una de las fronteras sobre la cual el feudalismo se reproducirá más tardíamente y con características propias. Este análisis tiene como punto de partida una similitud al nivel más profundo de la organización social, ya que en las dos zonas predominó la familia nuclear, pero las estructuras y evoluciones de estas dos regiones fueron distintas. La tesis es que en la base de esta diferencia se encuentran dos cualidades institucionales diferentes que hicieron al modo de producción en las mencionadas centurias. Entre el conjunto de casos que se pueden tener en cuenta para este estudio, dos grupos de fueros polarizan nuestra atención: Sahagún (1085, 1152) y Sepúlveda (1076, 1300)2. La consideración de estos códigos será acompañada por otra documentación.In the present study are compared the institutional foundations of two areas of the feudal system between the XI and XII centuries. One of them León y Castilla to the north of the Duero, corresponds to the center of the feudalism and resembles in its features and essential chronology to France between the Loire to the Rhine, to the central-north of Italy, Flandes, south east of England and north of the catalano-aragonese region. It's the nuclear area of the system. The other, to the south of the Duero, is the Extremadura Histórica, ranging from this river to the Central System and it corresponds with one of the frontiers on which feudalism will play later and with its own characteristics. This analysis take as its starting point a similarity to the deepest level of social organization since in the two areas dominated the nuclear family but the structures and developments of these two regions they were different. The thesis is that in the base of this difference are two differents institutional qualities that made to the mode of production in the mentioned centuries. Among the set of cases that can be considered for this study two groups of Fueros polarized our attention: Sahagún (1085, 1152) and Sepúlveda (1076, 1300). The consideration of these codes it will be accompanied by other documentation.Fil: Astarita, Carlos Alberto Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Investigaciones en Humanidades y Ciencias Sociales; Argentina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educacion; Argentina. Universidad de Buenos Aires; Argentin

Photooxygenation of furans in water and ionic liquid solutions

Photooxygenation of differently functionalized furans is investigated in aqueous solutions and in ionic liquids [emim]Br and [bmim]BF4. The reaction is generally selective and the final products derive from rearrangement of the intermediate endoperoxides, depending mainly on the polarity and/or nucleophilic nature of the solvent

Trajectory Perturbation in Surrogate Safety Indicators

Abstract Traffic conflicts based surrogate safety indicators have been applied extensively on real trajectories and in simulation. Such indicators can be useful to assess the safety of a given scenario without the need to use real crash data (which in many cases may be unavailable). Unfortunately, all traffic conflict indicators that are commonly used have a structural limitation: they are not able to consider potential conflicts with roadside obstacles or barriers and conflicts between vehicles which are travelling on non-conflicting trajectories. This limitation is a serious limitation since crash data analy sis shows that at least 40% of fatal crashes are originated by single vehicle accidents against a fixed object or by vehicles travelling in opposite directions. This paper is intended as a concept paper that presents an alternative view on conflict safety indicators showing that new indicators can be generated by the perturbation of vehicle trajectories overcoming the above indicated limitations