Variantes en el uso del concepto de natura en la teoría política medieval a partir de la segunda mitad del siglo XIII : natura multipliciter dicitur

La circulación hacia mediados del siglo XIII de los libri morales de Aristóteles transformó ampliamente la ética y el pensamiento político de la edad media. El conocimiento medieval de la filosofía moral aristotélica produjo un cambio cualitativo en diferentes temas de la filosofía práctica; como consecuencia de ello, a partir del siglo XIII, una parte importante de la teoría política tomó de Aristóteles el concepto de natura y muchos tratados se apoyaron en él y lo utilizaron para fundamentar el nacimiento del orden político que Aristóteles llamó polis, Tomás de Aquino civitas vel provincia y Juan de París communitas civitatis vel regni. Con todo, aunque el concepto aristotélico de natura fue relevante y aunque el modelo aristotélico logró inspirar a los autores de textos políticos medievales, la natura aristotélica no fue la única natura a la que recurrieron los textos políticos al momento de fundamentar teóricamente el surgimiento del orden político. El artículo analiza los diferentes conceptos de natura y reconstruye su lugar dentro de las explicaciones del nacimiento y constitución de las distintas variantes del orden político en la filosofía política medieval.

Chemical composition of bottom sediments from the Discovery Deep, Red Sea rift zone

Hot brines in depressions of the central Red Sea contain thousands of times more iron, manganese and other metals than . After removal of salts, approximately half of sediments from these depressions consists of iron hydroxides and they are enriched in zinc, copper, lead and molybdenum. Hydrothermal deposits with the same complex of metals, located along the coast of the Red Sea, are correlated with faults and may be due to occurrences of Tertiary volcanism. Brines of similar composition are known in the Cheleken Peninsula. Certain geological and geochemical data indicate that such brines are of relatively deep origin.

Chemistry of orthopyroxenes, clinopyroxenes, and spinels of ODP Hole 103-637A peridotites

Mineral compositions of the plagioclase-bearing ultramafic tectonites dredged and cored seaward of the continental slope of the Galicia margin (Leg 103, Site 637) were compared to mineral compositions from onshore low-pressure ultramafic bodies (southeastern Ronda, western Pyrenees, and Lizard Point), on the basis of standardized (30-s counting time) probe analyses. The comparison was extended to some plagioclase-free harzburgites related to ophiolites (Santa Elena in Costa Rica, north Oman, and the Humboldt body in New Caledonia) on the basis of new analytical data and data from the literature. The behavior of Cr, Na, Al, Mg, Fe, Ni, and Ti in olivine, pyroxenes, and spinel was examined in order to distinguish between the effects of partial melting and mineral facies change, from the spinel to plagioclase stability fields. The peridotite from the Galicia margin appears slightly depleted in major incompatible elements and experienced a minor partial melting. However, it experienced large scale but heterogeneous recrystallization in the plagioclase field. These features are very similar to those observed in Ronda, whereas in the western Pyrenees the minerals exemplify a very minor partial-melting event (or none at all) and have retained compositions corresponding to those of the relatively high-pressure Seiland sub facies. The minerals from the Lizard Point peridotite have characteristics (low Mg/(Mg + Fe) ratio; high Cr/(Cr + Al) ratio in spinel) more related to cumulate from a differentiated tholeiitic melt than related to ophiolitic tectonite. Diffusion profiles of Al and Cr across pyroxenes and spinel show that recrystallization features occurred at different speeds or temperatures in the different bodies. The pyroxenes from Ronda would have experienced recrystallization about 14 times faster than the peridotite from the Galicia margin. The western Pyrenean lherzolites also experienced rapid recrystallization; nevertheless, because they are of a different mineral facies, the data are not directly comparable to that from Ronda and Galicia. The harzburgite at Santa Elena as well as a xenolith from alkali basalt exemplify rapid cooling characterized by very weak re-equilibration. Recrystallization speed is related to emplacement speed in the present geological environment. The slow-rising Galicia margin peridotite was emplaced by thinning of the lithospheric subcontinental mantle near an incipient mid-oceanic ridge. The fast-rising peridotites from Ronda and the western Pyrenees were hot diapirs emplaced from the asthenosphere along transcurrent faults, possibly related to the opening of the Atlantic Ocean.

Heat flow measurements on METEOR cruise M86/5

Mud volcanoes (MV) are sources of mass and energy, transported from deeper levels of the sediment pile to the surface. Together with fluid and gas, thermal energy is emitted through these structures. Therefore heat flow determination is a sensible tool to detect and quantify the amount of convective flow. In the Gulf of Cadiz several mud volcanoes can be found along major tectonic lines (SWIM faults). We employ geothermal measurements to observe the activity of mud volcanoes and possible leakage at the faults apart from pronounced structures.

Summary of physical properties on cores used for petrofabric analyses triaxial experiments at DSDP Leg 67 Holes

Deformation features within the cores are studied with a view towards elucidating the structure of the Middle America Trench along the transect drilled during Leg 67. Where possible, inferences are made as to the physical environment of deformation. Extensional tectonics prevails in the area of the seaward slope and trench. Fracturing and one well-preserved normal fault are found mostly within the lower Miocene chalks, at the base of the sedimentary section. These chalks have high porosities (40%-60%) and water content (30%-190%, based on % dry wt.). Experimental triaxial compression tests conducted on both dry and water-saturated samples of chalk from Holes 495 and 499B show that only in the saturated samples is more brittle behavior observed. Brittle failure of the chalks is greatly facilitated by pore fluid pressures that lead to low effective pressures. Additional embrittlement (weakening) can take place as a result of the imposed extensional stress resulting from bending of a subducting elastic oceanic plate. The chalks exhibit, in a landward direction, an increase in density and mechanical strength and a decrease in water content. These changes are attributed to mechanical compaction that may have resulted from tectonic horizontal compression. The structure of the landward slope is not well understood because the slope sites had to be abandoned due to the presence of gas hydrate. The relationship of the chaotic, brittle deformation (observed in the cores from Hole 494A) at the base of the landward slope to tectonic processes remains unclear. The deformation observed on the slope sites (Holes 496 and 497) is mostly fracturing and near-vertical sigmoidal veinlets. These are interpreted as being the result of gas/fluid overpressurization due to the decomposition of the gas hydrate, and not due to tectonic loading of accreted sediments. Aside from four small displacement (less than 1cm) reverse faults observed in the lower Miocene chalks (which may be the product of soft-sediment deformation), there is a noticeable absence of structures reflecting a dominance of horizontal (tectonic) compression along the transect drilled. The absence of such features, the lack of continuity of sediment types across the trench-landward slope, and the normal stratigraphic sequence in Hole 494A do not support any known accretionary model.

Las transgresiones sexuales de Clitofonte : Seducción y adulterio

El protagonista de la novela de Aquiles Tacio Leucipa y Clitofonte incurre en dos tipos de transgresiones de la moral sexual: seducción de una joven virgen y adulterio. Analizaremos aquí el modo en que ambas faltas aparecen representadas en la novela, su definición, las reacciones sociales ante ellas y las penas que pueden aplicárseles, y compararemos esa representación con las caracterizaciones de estos delitos en las leyes griegas y romanas que interactuaban en el complejo panorama cultural del período imperial. Postulamos que este análisis puede aportar datos que contribuyan a la comprensión de la historia social y de los códigos morales y legales que delimitaban las relaciones lícitas e ilícitas entre los sexos, pues a pesar de que la ficción novelesca no refleja en forma directa la realidad histórica, afloran en ella elementos propios del contexto socio-cultural en que autor y público están inmersos

Paleomagnetism and bedding orientations at DSDP Sites 87-582, 87-583 and 87-584

Paleomagnetic measurements of sediment samples provide the magnetostratigraphy at Deep Sea Drilling Sites 582, 583, and 584 in the Nankai Trough and the Japan Trench. Drastic changes in the rate of sediment accumulation are documented by the magnetostratigraphic and biostratigraphic correlations. The changes in the accumulation rate correspond to the supply of sediments and variations in the accretionary process, which are directly related to the tectonic cycles in the geologic evolution of the Japanese island arc. Faults and folds within the drilled sedimentary sequences are oriented by paleomagnetic declination. Their directions and stress patterns are related to the relative plate motion along the trough and trench. The original remanent magnetization of the sediment was modified and remagnetized in the tectonic process of accretion by physical deformation, faulting, and intrusion of dewatering veinlets.

Measurements of velocity-dependent and slip-dependent frictional strength in laboratory friction experiments on natural samples from IODP Expedition 316 and ODP Hole 190-1174B

Slowslip forms part of the spectrum of fault behaviour between stable creep and destructive earthquakes. Slow slip occurs near the boundaries of large earthquake rupture zones and may sometimes trigger fast earthquakes. It is thought to occur in faults comprised of rocks that strengthen under fast slip rates, preventing rupture as a normal earthquake, or on faults that have elevated pore-fluid pressures. However, the processes that control slow rupture and the relationship between slow and normal earthquakes are enigmatic. Here we use laboratory experiments to simulate faulting in natural rock samples taken from shallow parts of the Nankai subduction zone, Japan, where very low-frequency earthquakes - a form of slow slip - have been observed.We find that the fault rocks exhibit decreasing strength over millimetre-scale slip distances rather than weakening due to increasing velocity. However, the sizes of the slip nucleation patches in our laboratory simulations are similar to those expected for the very lowfrequency earthquakes observed in Nankai. We therefore suggest that this type of fault-weakening behaviour may generate slow earthquakes. Owing to the similarity between the expected behaviour of slow earthquakes based on our data, and that of normal earthquakes during nucleation, we suggest that some types of slow slip may represent prematurely arrested earthquakes.

Las transgresiones sexuales de Clitofonte : Seducción y adulterio

El protagonista de la novela de Aquiles Tacio Leucipa y Clitofonte incurre en dos tipos de transgresiones de la moral sexual: seducción de una joven virgen y adulterio. Analizaremos aquí el modo en que ambas faltas aparecen representadas en la novela, su definición, las reacciones sociales ante ellas y las penas que pueden aplicárseles, y compararemos esa representación con las caracterizaciones de estos delitos en las leyes griegas y romanas que interactuaban en el complejo panorama cultural del período imperial. Postulamos que este análisis puede aportar datos que contribuyan a la comprensión de la historia social y de los códigos morales y legales que delimitaban las relaciones lícitas e ilícitas entre los sexos, pues a pesar de que la ficción novelesca no refleja en forma directa la realidad histórica, afloran en ella elementos propios del contexto socio-cultural en que autor y público están inmersos

Las transgresiones sexuales de Clitofonte : Seducción y adulterio

El protagonista de la novela de Aquiles Tacio Leucipa y Clitofonte incurre en dos tipos de transgresiones de la moral sexual: seducción de una joven virgen y adulterio. Analizaremos aquí el modo en que ambas faltas aparecen representadas en la novela, su definición, las reacciones sociales ante ellas y las penas que pueden aplicárseles, y compararemos esa representación con las caracterizaciones de estos delitos en las leyes griegas y romanas que interactuaban en el complejo panorama cultural del período imperial. Postulamos que este análisis puede aportar datos que contribuyan a la comprensión de la historia social y de los códigos morales y legales que delimitaban las relaciones lícitas e ilícitas entre los sexos, pues a pesar de que la ficción novelesca no refleja en forma directa la realidad histórica, afloran en ella elementos propios del contexto socio-cultural en que autor y público están inmersos

Chemical composition and elemental oxide ratios to AI2O3 of bulk solids at DSDP Leg 64 Holes

Analyses of sediments from Leg 64 sites reveal a diverse and in one case unique geochemistry. Sites are characterized by high heat flow along an active, divergent plate boundary, or rapid accumulation of diatom muds, or both. The geochemical trends of Sites 474-476 at the tip of Baja California reflect changes4n the percentages of sedimentary components - particularly biogenous matter and mineralogy - that support interpretations of sedimentary environments inferred to be present since the commencement of subsidence along this young, passive continental margin. The sediments below dolerite sills in Holes 477, 477A, 478, and 481 show major mineralogic and chemical deviations from "average" hemipelagic sediments. The sills appear to have two functions: (1) they allow hydrothermal circulation and metamorphism in a partially closed system by trapping heat and fluids emanating from below, and (2) they expel heated interstitial fluids at the moment of intrusion and mobilize elements, most likely leading to the formation of metalliferous deposits along the surface traces of normal faults in the basin. The hydrothermal system as a whole appears to be localized and ephemeral, as is indicated by the lack of similar geochemical trends and high heat flow at Sites 478 and 481. Site 479 illustrates sedimentation in an oxygen-minimum zone with anoxic sediments and concomitant geochemical trends, especially for MnO. With few exceptions, geochemical trends are remarkably constant with depth, suggesting that Site 479 can serve as an "internal" standard or average sediment against which the magnitude of hydrothermal alteration at the basinal Sites 477, 478, and 481 can be measured.