973 resultados para Sin--Islam--Early works to 1800


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The benthic foraminifer fauna at Sumisu Rift Sites 790 and 791 indicates that a deep open-ocean (>2300 m) or a basin with open-ocean access existed between 1.1 and 0.7 Ma at the time of the initiation of rifting. The appearance of a low- to medium-oxygen fauna (1600-2300 m) between 0.7 and 0.5 Ma suggests that the open-ocean access may have been terminated at this time because of the development of volcanoes and rift flank uplifts around the basin. The occurrence of low-oxygen faunas at 0.03 Ma suggests a secondary closing of the basin. The lower bathyal benthic faunas from lower Pliocene sediments of rift margin Site 788 suggest about 0.6-1.6 km of total basement uplift. This uplift may have led to the formation of the major hiatus between 2.3 and <0.3 Ma. The faunal changes of benthic foraminifers at Sites 792 and 793 in the forearc basin document a shallowing water depth from below the carbonate compensation depth (CCD) (about 3.5 km) in the late early Oligocene to the present depths of 1800 and 2975 m, respectively. These data suggest about 1 km of total basement uplift in the inner part of the forearc basin (Site 792) and about 0.6 km total basement subsidence in the central part of the forearc basin (Site 793) since about 31 Ma. The former uplift led to a thinner sediment accumulation (800 m) and the latter subsidence to a thicker sediment accumulation (1400 m) at these sites. Faunal changes of benthic foraminifers observed in Sites 782 and 786 sequences drilled at the outer-arc high document a deepening water depth from 1.3 to 2.1 km in late Eocene to the present depth of about 3 km. These data suggest about 1.1-1.9 and 1.3-2.1 km of total basement subsidence at Sites 786 and 782, respectively. These results indicate total basement uplift in the inner part of the Bonin arc-trench system since late Oligocene and total basement subsidence in the outer part of the system since late Eocene. The last occurrence (LO) of Stilostomella spp. and Pleurostomella spp. and the first occurrence (F0) of Bulimina aculeata d'Orbigny occurred consistently at 0.7 Ma at all three arc proximal sites (790,791, and 792). This fact is taken to suggest a change of water mass, from one originating from the central part of the ocean to that originating from ocean-margin areas at that time.

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Early Pliocene to middle late Miocene hemipelagic and distal turbidite sediments from Hole 1095B, near the Antarctic Peninsula, yield moderately abundant, moderately well preserved radiolarian faunas and other biosiliceous material (diatoms, silicoflagellates, and sponge spicules). Preservation characteristics, however, vary strongly even between closely related samples, and there are many intervals of poor preservation. In the 140- to 460-meters below seafloor interval studied, it was possible to identify the following standard Southern Ocean radiolarian zones: Upsilon, Tau, Amphymenium challengerae, Acrosphaera? labrata, Siphonosphaera vesuvius, and upper Acrosphaera australis (total age range ~4-10 Ma). Some normally common radiolarian groups, such as actinommids, are unusually rare in the studied material, and the relative ranges of several individual species, such as Acrosphaera labrata vs. A. australis, appear to be somewhat anomalous. These observations imply that the ranges of taxa in this section may be somewhat diachronous, due to either local ecologic factors and/or the highly variable preservation of the faunas. Thus, the ages of events reported are probably only approximate, although they are still useful for constraining the age of sediments in this section.

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The Olvés Church is a Lhree naves basilica. From its construction in 1767, it sufTercd important damages and successivc reparations. The church is built on a claycy hillock on top of the village with vcry fort slopcs. The retaining walls Lhat surround the church havc sufTered movements. A soil sludy was done to know its propcrtics and the reason of the movement. Also, the structural roof is broken and it is not fixed to thc walls that can movc. Thc first phase is done, with a pavcd squa rc ovcr an ancient cemetery. The next phase is a new roof structure to support the lean walls. Al'ter that done, the repair inside can start.

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Debido al gran interés existente en el ahorro y recuperación de energía, y en el deseo de obtener productos que permitan usos beneficiosos del fango procedente de la depuración del agua residual, la digestión anaerobia es el proceso de estabilización de uso más extendido. El tiempo de retención de sólidos es un factor clave en el proceso de digestión anaerobia. En base al tiempo de retención de sólidos, se dimensiona el volumen de los digestores anaerobios para así obtener la reducción de materia orgánica deseada, con la correspondiente producción de biogás. La geometría del digestor y su sistema de agitación deben ser adecuados para alcanzar el tiempo de retención de sólidos de diseño. Los primeros trabajos sobre la agitación de los digestores realizaban únicamente experimentos con trazadores y otros métodos de medición. En otros casos, la mezcla era evaluada mediante la producción de biogás. Estas técnicas tenían el gran hándicap de no conocer lo que sucedía realmente dentro del digestor y sólo daban una idea aproximada de su funcionamiento. Mediante aplicación de la mecánica de fluidos computacional (CFD) es posible conocer con detalle las características del fluido objeto de estudio y, por lo tanto, simular perfectamente el movimiento del fango de un digestor anaerobio. En esta tesis se han simulado mediante CFD diferentes digestores a escala real (unos 2000 m3 de volumen) agitados con bomba/s de recirculación para alcanzar los siguientes objetivos: establecer la influencia de la relación entre el diámetro y la altura, de la pendiente de la solera, del número de bombas y del caudal de recirculación en dichos digestores, definir el campo de velocidades en la masa de fango y realizar un análisis energético y económico. Así, es posible conocer mejor cómo funciona el sistema de agitación de un digestor anaerobio a escala real equipado con bomba/s de recirculación. Los resultados obtenidos muestran que una relación diámetro/altura del digestor por encima de 1 empeora la agitación del mismo y que la pendiente en la solera del digestor favorece que la masa de fango esté mejor mezclada, siendo más determinante la esbeltez del tanque que la pendiente de su solera. No obstante, también es necesario elegir adecuadamente los parámetros de diseño del sistema de agitación, en este caso el caudal de recirculación de fango, para obtener una agitación completa sin apenas zonas muertas. En el caso de un digestor con una geometría inadecuada es posible mejorar su agitación aumentando el número de bombas de recirculación y el caudal de las mismas, pero no se llegará a alcanzar una agitación total de la masa de fango debido a su mal diseño original. Anaerobic digestion is the process for waste water treatment sludge stabilization of more widespread use due to the huge interest in saving and recovering energy and the wish to obtain products that allow beneficial uses for the sludge. The solids retention time is a key factor in the anaerobic digestion. Based on the solids retention time, volume anaerobic digester is sized to obtain the desired reduction in organic matter, with the corresponding production of biogas. The geometry of the digester and the stirring system should be adequate to achieve the design solid retention time. Early works on digesters stirring just performed tracer experiments and other measurement methods. In other cases, mixing was evaluated by biogas production. These techniques had the great handicap of not knowing what really happened inside the digester and they only gave a rough idea of its operation. By application of computational fluid dynamics (CFD), it is possible to know in detail the characteristics of the fluid under study and, therefore, simulate perfectly the sludge movement of an anaerobic digester. Different full-scale digesters (about 2000 m3 of volume) agitated with pump/s recirculation have been simulated by CFD in this thesis to achieve the following objectives: to establish the influence of the relationship between the diameter and height, the slope of the bottom, the number of pumps and the recirculation flow in such digesters, to define the velocity field in the mass of sludge and carry out an energy and economic analysis. Thus, it is possible to understand better how the agitation system of a full-scale anaerobic digester equipped with pump/s recirculation works. The results achieved show that a diameter/height ratio of the digester above 1 worsens its stirring and that the slope of the digester bottom favors that the mass of sludge is better mixed, being more decisive the tank slenderness than the slope of its bottom. However, it is also necessary to select properly the design parameters of the agitation system, in this case the sludge recirculation flow rate, for a complete agitation with little dead zones. In the case of a digester with inadequate geometry, its agitation can be improved by increasing the number of recirculation pumps and flow of them, but it will not reach a full agitation of the mass of sludge because of the poor original design.

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The Saccharomyces cerevisiae Rlp7 protein has extensive identity and similarity to the large ribosomal subunit L7 proteins and shares an RNA-binding domain with them. Rlp7p is not a ribosomal protein; however, it is encoded by an essential gene and therefore must perform a function essential for cell growth. In this report, we show that Rlp7p is a nucleolar protein that plays a critical role in processing of precursors to the large ribosomal subunit RNAs. Pulse–chase labeling experiments with Rlp7p-depleted cells reveal that neither 5.8SS, 5.8SL, nor 25S is produced, indicating that both the major and minor processing pathways are affected. Analysis of processing intermediates by primer extension indicates that Rlp7p-depleted cells accumulate the 27SA3 precursor RNA, which is normally the major substrate (85%) used to produce the 5.8S and 25S rRNAs, and the ratio of 27SBL to 27SBS precursors changes from approximately 1:8 to 8:1 (depleted cells). Because 27SA3 is the direct precursor to 27SBS, we conclude that Rlp7p is specifically required for the 5′ to 3′ exonucleolytic trimming of the 27SA3 into the 27SBS precursor. As it is essential for processing in both the major and minor pathways, we propose that Rlp7p may act as a specificity factor that binds precursor rRNAs and tethers the enzymes that carry out the early 5′ to 3′ exonucleolytic reactions that generate the mature rRNAs. Rlp7p may also be required for the endonucleolytic cleavage in internal transcribed spacer 2 that separates the 5.8S rRNA from the 25S rRNA.

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Barley (Hordeum vulgare L.) plants were grown at different photon flux densities ranging from 100 to 1800 μmol m−2 s−1 in air and/or in atmospheres with reduced levels of O2 and CO2. Low O2 and CO2 partial pressures allowed plants to grow under high photosystem II (PSII) excitation pressure, estimated in vivo by chlorophyll fluorescence measurements, at moderate photon flux densities. The xanthophyll-cycle pigments, the early light-inducible proteins, and their mRNA accumulated with increasing PSII excitation pressure irrespective of the way high excitation pressure was obtained (high-light irradiance or decreased CO2 and O2 availability). These findings indicate that the reduction state of electron transport chain components could be involved in light sensing for the regulation of nuclear-encoded chloroplast gene expression. In contrast, no correlation was found between the reduction state of PSII and various indicators of the PSII light-harvesting system, such as the chlorophyll a-to-b ratio, the abundance of the major pigment-protein complex of PSII (LHCII), the mRNA level of LHCII, the light-saturation curve of O2 evolution, and the induced chlorophyll-fluorescence rise. We conclude that the chlorophyll antenna size of PSII is not governed by the redox state of PSII in higher plants and, consequently, regulation of early light-inducible protein synthesis is different from that of LHCII.

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The last few years have witnessed the exponential growth of platforms like Uber and Airbnb and the creation of countless other less well-known examples. The expansion of the on-demand economy puts huge pressure on regulators to adapt it to the existing frameworks for labour and taxation. The rapid growth of the sector also divides experts: it is seen by many as threat for working conditions, and by others as an incredible opportunity. The purpose of this essay is to take a balanced perspective on what we know about the on-demand economy and what needs further investigation. More research is needed on the individual cases before one can draw conclusions on how this new sector works. The political economy of the sector is made even more interesting by the fact that the technology is developing faster than the regulation. Yet, our plea to policy-makers is to refrain from legislating too early and to take the time to understand how the supply and the demand of these services behave and their equilibrium.

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"Comparative table of the MSS. and editions": v. 1, p. [xxxvi]

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Includes index.

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pt. 1. Egyptian text in hieroglyphics.--pt.2. Vocabulary.--pt. 3. Translation.

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First published 1897.

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Includes indexes.