964 resultados para 100% minus sum of oxides
Resumo:
Fifty samples of Roman time soil preserved under the thick ash layer of the A.D.79 eruption of Mt Vesuvius were studied by pollen analysis: 33 samples from a former vineyard surrounding a Villa Rustica at Boscoreale (excavation site 40 x 50 m), 13 samples taken along the 60 m long swimming pool in the sculpture garden of the Villa of Poppaea at Oplontis, and four samples from the formal garden (12.4 x 17.5 m) of the House of the Gold Bracelet in Pompeii. To avoid contamination with modern pollen all samples were taken immediately after uncovering a new portion of the A.D. 79 soil. For comparison also samples of modern Italian soils were studied. Using standard methods for pollen preparation the pollen content of 15 of the archaeological samples proved to be too little to reach a pollen sum of more than 100 grains. The pollen spectra of these samples are not shown in the pollen tables. (Flotation with a sodium tungstate solution, Na2WO4, D = 2.05, following treatment with HCl and NaOH would probably have given a somewhat better result. This method was, however, not available as too expensive at that time.) Although the archaeological samples were taken a few meters apart their pollen values differ very much from one sample to the other. E.g., at Boscoreale (SW quarter). the pollen values of Pinus range from 1.5 to 54.5% resp. from 1 to 244 pine pollen grains per 1 gram of soil, the extremes even found under pine trees. Vitis pollen was present in 7 of the 11 vineyard samples from Boscoreale (NE quarter) only. Although a maximum of 21.7% is reached, the values of Vitis are mostly below 1.5%. Even the values of common weeds differ very much, not only at Boscoreale, but also at the other two sites. The pollen concentration values show similar variations: 3 to 3053 grains and spores were found in 1 g of soil. The mean value (290) is much less than the number of pollen grains, which would fall on 1 cm2 of soil surface during one year. In contrast, the pollen and spore concentrations of the recent soil samples, treated in exactly the same manner, range from 9313 to almost 80000 grains per 1 g of soil. Evidently most of the Roman time pollen has disappeared since its deposition, the reasons not being clear. Not even species which are known to have been cultivated in the garden of Oplontis, like Citrus and Nerium, plant species with easily distinguishable pollen grains, could be traced by pollen analysis. The loss of most of the pollen grains originally contained in the soil prohibits any detailed interpretation of the Pompeian pollen data. The pollen counts merely name plant species which grew in the region, but not necessarily on the excavated plots.
Resumo:
The "SESAME_IT3_ZooAbundance_0-50-100m_SZN" dataset contains data of mesozooplankton species composition and abundance (ind. m-3) from samples collected in the Sicily Channel in the early spring of 2008 (17,18 March) during the SESAME-WP2 cruise IT3. Samples were collected by vertical tows with a closing WP2 net (56 cm diameter, 200 µm mesh size) in the following depth layers: 100-200 m, 50-100 m, 0-50 m. Sampling was always performed in light hours with the exception of station S-IT3-03 where zooplankton were collected in dark hours. A flowmeter was applied to the mouth of the net, however, due to its malfunctioning, the volume of filtered seawater was calculated by multiplying the the area by the height of the sampled layer from winch readings. After collection, each sample was split in two halves (1/2) after careful mixing with graduated beakers. Half sample was immediately fixed and preserved in a formaldehyde-seawater solution (4% final concentration) for species composition and abundance. The other half sample was kept fresh for biomass measurements (data already submitted to SESAME database in different files).Here, only the zooplankton abundance of samples in the upper layers 0-50 m and 50-100 m are presented. The abundance data of the samples in the layer 50-100 m will be submitted later in a separate file. The volume of filtered seawater was estimated by multiplying the the area by the height of the sampled layer from winch readings. Identification and counts of specimens were performed on aliquots (1/20-1/5) of the fixed sample or on the total sample (half of the original sample) by using a graduate large-bore pipette. Copepods were identified to the species level and separated into females, males and juveniles (copepodites). All other taxa were identified at the species level when possible, or at higher taxonomic levels. Taxonomic identification was done according to the most relevant and updated taxonomic literature. Total mesozooplankton abundance was computed as sum of all specific abundances determined as explained above.
Resumo:
Pot experiments were performed to evaluate the phytoremediation capacity of plants of Atriplex halimus grown in contaminated mine soils and to investigate the effects of organic amendments on the metal bioavailability and uptake of these metals by plants. Soil samples collected from abandoned mine sites north of Madrid (Spain) were mixed with 0, 30 and 60 Mg ha?1 of two organic amendments, with different pH and nutrients content: pine-bark compost and horse- and sheep-manure compost. The increasing soil organic matter content and pH by the application of manure amendment reduced metal bioavailability in soil stabilising them. The proportion of Cu in the most bioavailable fractions (sum of the water-soluble, exchangeable, acid-soluble and Fe?Mn oxides fractions) decreased with the addition of 60 Mg ha?1 of manure from 62% to 52% in one of the soils studied and from 50% to 30% in the other. This amendment also reduced Zn proportion in water-soluble and exchangeable fractions from 17% to 13% in one of the soils. Manure decreased metal concentrations in shoots of A. halimus, from 97 to 35 mg kg?1 of Cu, from 211 to 98 mg kg?1 of Zn and from 1.4 to 0.6 mg kg?1 of Cd. In these treatments there was a higher plant growth due to the lower metal toxicity and the improvement of nutrients content in soil. This higher growth resulted in a higher total metal accumulation in plant biomass and therefore in a greater amount of metals removed from soil, so manure could be useful for phytoextraction purposes. This amendment increased metal accumulation in shoots from 37 to 138 mg pot?1 of Cu, from 299 to 445 mg pot?1 of Zn and from 1.8 to 3.7 mg pot?1 of Cd. Pine bark amendment did not significantly alter metal availability and its uptake by plants. Plants of A. halimus managed to reduce total Zn concentration in one of the soils from 146 to 130 mg kg?1, but its phytoextraction capacity was insufficient to remediate contaminated soils in the short-to-medium term. However, A. halimus could be, in combination with manure amendment, appropriate for the phytostabilization of metals in mine soils.
Resumo:
Molecular hydrogen strongly interacts with vicinal Ge(100) surfaces during preparation in a metal organic vapor phase epitaxy reactor. According to X-ray photoemission spectroscopy and Fourier-transform infrared spectroscopy results, we identify two characteristic reflection anisotropy (RA) spectra for H-free and monohydride-terminated vicinal Ge(100) surfaces. RAS allows in situ monitoring of the surface termination and enables spectroscopic hydrogen kinetic desorption studies on the Ge(100) surface. Comparison of evaluated values for the activation energy and the pre-exponential factor of H desorption evaluated at different photon energies reflects that H unevenly affects the shape of the RA spectrum.
Resumo:
La tesis doctoral se centra en la posibilidad de entender que la práctica de arquitectura puede encontrar en las prácticas comunicativas un apoyo instrumental, que sobrepasa cualquier simplificación clásica del uso de los medios como una mera aplicación superficial, post-producida o sencillamente promocional. A partir de esta premisa se exponen casos del último cuarto del siglo XX y se detecta que amenazas como el riesgo de la banalización, la posible saturación de la imagen pública o la previsible asociación incorrecta con otros individuos en presentaciones grupales o por temáticas, han podido influir en un crecimiento notable de la adquisición de control, por parte de los arquitectos, en sus oportunidades mediáticas. Esto es, como si la arquitectura hubiera empezado a superar y optimizar algo inevitable, que las fórmulas expositivas y las publicaciones, o más bien del exponer(se) y publicar(se), son herramientas disponibles para activar algún tipo de gestión intelectual de la comunicación e información circulante sobre si misma. Esta práctica de “autoedición” se analiza en un periodo concreto de la trayectoria de OMA -Office for Metropolitan Architecture-, estudio considerado pionero en el uso eficiente, oportunista y personalizado de los medios. Así, la segunda parte de la tesis se ocupa del análisis de su conocida monografía S,M,L,XL (1995), un volumen que contó con gran participación por parte de sus protagonistas durante la edición, y de cuyo proceso de producción apenas se había investigado. Esta publicación señaló un punto de inflexión en su género alterando todo formato y restricciones anteriores, y se ha convertido en un volumen emblemático para la disciplina que ninguna réplica posterior ha podido superar. Aquí se presenta a su vez como el desencadenante de la construcción de un “gran evento” que concluye en la transformación de la identidad de OMA en 10 años, paradójicamente entre el nacimiento de la Fundación Groszstadt y el arranque de la actividad de AMO, dos entidades paralelas clave anexas a OMA. Este planteamiento deviene de cómo la investigación desvela que S,M,L,XL es una pieza más, central pero no independiente, dentro de una suma de acciones e individuos, así como otras publicaciones, exposiciones, eventos y también artículos ensayados y proyectos, en particular Bigness, Generic City, Euralille y los concursos de 1989. Son significativos aspectos como la apertura a una autoría múltiple, encabezada por Rem Koolhaas y el diseñador gráfico Bruce Mau, acompañados en los agradecimientos de la editora Jennifer Sigler y cerca de una centena de nombres, cuyas aportaciones no necesariamente se basan en la construcción de fragmentos del libro. La supresión de ciertos límites permite superar también las tareas inicialmente relevantes en la edición de una publicación. Un objetivo general de la tesis es también la reflexión sobre relaciones anteriormente cuestionadas, como la establecida entre la arquitectura y los mercados o la economía. Tomando como punto de partida la idea de “design intelligence” sugerida por Michael Speaks (2001), se extrae de sus argumentos que lo esencial es el hallazgo de la singularidad o inteligencia propia de cada estudio de arquitectura o diseño. Asimismo se explora si en la construcción de ese tipo de fórmulas magistrales se alojaban también combinaciones de interés y productivas entre asuntos como la eficiencia y la creatividad, o la organización y las ideas. En esta dinámica de relaciones bidireccionales, y en ese presente de exceso de información, se fundamenta la propuesta de una equivalencia más evidenciada entre la “socialización” del trabajo del arquitecto, al compartirlo públicamente e introducir nuevas conversaciones, y la relación inversa a partir del trabajo sobre la “socialización” misma. Como si la consciencia sobre el uso de los medios pudiera ser efectivamente instrumental, y contribuir al desarrollo de la práctica de arquitectura, desde una perspectiva idealmente comprometida e intelectual. ABSTRACT The dissertation argues the possibility to understand that the practice of architecture can find an instrumental support in the practices of communication, overcoming any classical simplification of the use of media, generally reduced to superficial treatments or promotional efforts. Thus some cases of the last decades of the 20th century are presented. Some threats detected, such as the risk of triviality, the saturation of the public image or the foreseeable wrong association among individuals when they are introduced as part of thematic groups, might have encouraged a noticeable increase of command taken by architects when there is chance to intervene in a media environment. In other words, it can be argued that architecture has started to overcome and optimize the inevitable, the fact that exhibition formulas and publications, or simply the practice of (self)exhibition or (self)publication, are tools at our disposal for the activation of any kind of intellectual management of communication and circulating information about itself. This practice of “self-edition” is analyzed in a specific timeframe of OMA’s trajectory, an office that is considered as a ground-breaking actor in the efficient and opportunistic use of media. Then the second part of the thesis dissects their monograph S,M,L,XL (1995), a volume in which its main characters were deeply involved in terms of edition and design, a process barely analyzed up to now. This publication marked a turning point in its own genre, disrupting old formats and traditional restrictions. It became such an emblematic volume for the discipline that none of the following attempts of replica has ever been able to improve this precedent. Here, the book is also presented as the element that triggers the construction of a “big event” that concludes in the transformation of OMA identity in 10 years. Paradoxically, between the birth of the Groszstadt Foundation and the early steps of AMO, both two entities parallel and connected to OMA. This positions emerge from how the research unveils that S,M,L,XL is one more piece, a key one but not an unrelated element, within a sum of actions and individuals, as well as other publications, exhibitions, articles and projects, in particular Bigness, Generic City, Euralille and the competitions of 1989. Among the remarkable innovations of the monograph, there is an outstanding openness to a regime of multiple authorship, headed by Rem Koolhaas and the graphic designer Bruce Mau, who share the acknowledgements page with the editor, Jennifer Sigler, and almost 100 people, not necessarily responsible for specific fragments of the book. In this respect, the dissolution of certain limits made possible that the expected tasks in the edition of a publication could be trespassed. A general goal of the thesis is also to open a debate on typically questioned relations, particularly between architecture and markets or economy. Using the idea of “design intelligence”, outlined by Michael Speaks in 2001, the thesis pulls out its essence, basically the interest in detecting the singularity, or particular intelligence of every office of architecture and design. Then it explores if in the construction of this kind of ingenious formulas one could find interesting and useful combinations among issues like efficiency and creativity, or organization and ideas. This dynamic of bidirectional relations, rescued urgently at this present moment of excess of information, is based on the proposal for a more evident equivalence between the “socialization” of the work in architecture, anytime it is shared in public, and the opposite concept, the work on the proper act of “socialization” itself. As if a new awareness of the capacities of the use of media could turn it into an instrumental force, capable of contributing to the development of the practice of architecture, from an ideally committed and intelectual perspective.