902 resultados para Kerr black holes Kerr metric buchi neri di Kerr metrica di Kerr ergosfera ergosphera orizzonte degli eventi event horizon


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Legs 59 and 60 of the International Phase of Oceanic Drilling (IPOD) were designed to study the nature and history of volcanism of the active Mariana arc, its currently spreading inter-arc basin (the Mariana Trough), and the series of inactive basins and intervening ridges that lie to the west. The older basins and ridges were drilled during Leg 59 as the first part of a transect of single-bit holes drilled in each major basin and ridge. The eastern part of the transect - the technically active region - was drilled during Leg 60. The evolution of island-arc volcanos and magma genesis associated with lithospheric subduction remain some of the most complex petrologic problems confronting us. Many types of source material (mantle, oceanic crust, continental crust) and an unusually wide range of possible physical conditions at the time of magma genesis must be identified even before the roles of partial melting and subsequent magma fractionation, mixing, and contamination can be assessed.

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Soviet sedimentologists use the term "coarse silt" to denote the size fraction 0.1 to 0.05 mm (50-100 µm). Petelin (1961) has shown that this fraction is most diagnostic for terrigeneous and volcanogenic mineral assemblages and provinces in Recent deep-sea sediments, because of its greatest variability of both heavy and light non-opaque minerals, which may be easily identified by the common immersion method. We believe that the fraction is suitable for mineralogical study of unconsolidated and friable sediments from DSDP cores as well, if the objective is to investigate their source area and transporation tracks. In the case of fine-grained oceanic sediments, mineral composition of the coarse silt does not differ markedly from that of the "coarse fraction" (>62 µm).

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Uncertainty currently exists about the removal of carbon (C) and phosphorus (P) from the oceanic reservoir, especially in low oxygen settings. In this paper, the cycling of C and P is examined in sediments from the anoxic Saanich Inlet, cored by Ocean Drilling Program (ODP) Leg 169S in 1996 at two sites. Although Corg/Porg ratios are high and increase with depth in the Saanich Inlet, this effect is due largely to a remobilization of P from an organic matter sink to an authigenic sink. Reducible sedimentary components act as temporary shuttles in this process even in this anoxic setting, with the ultimate burial sink for the remobilized P being carbonate fluorapatite. The effective Corg/Preactive molar ratio appears to be about 150-200, indicating some preferential loss of P compared to C during organic matter degradation, but not approaching previously reported values of over 3000 in black shales. Reactive P accumulation rates in this basin range from 10,000-60,000 µmol/cm**2/kyr, greatly exceeding the range of 500-8000 µmol/cm**2/kyr found in most continental-margin settings, including regions of modern phosphogenesis. The initiation of marine sedimentation in the Saanich Inlet occurred after deglaciation, and the high rates of P burial seen here may provide an end-member example of the effects of sea level and margin sedimentation on the distribution of P within the marine P cycle.

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La tesi analizza il fenomeno dell'Appropriazione Culturale, ne definisce le varie forme e si concentra su vari casi di Appropriazione Culturale negli anni 2000, con un focus sull'Appropriazione della cultura Afroamericana.

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The aim of this master thesis is to study the exponential decay of solutions of elliptic partial equations. This work is based on the results obtained by Agmon. To this purpose, first, we define the Agmon metric, that plays an important role in the study of exponential decay, because it is related to the rate of decay. Under some assumptions on the growth of the function and on the positivity of the quadratic form associated to the operator, a first result of exponential decay is presented. This result is then applied to show the exponential decay of eigenfunctions with eigenvalues whose real part lies below the bottom of the essential spectrum. Finally, three examples are given: the harmonic oscillator, the hydrogen atom and a Schrödinger operator with purely discrete spectrum.

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In questo elaborato si vuole studiare l’implementazione di un sistema di comunicazione dati e audio basato su segnali Ultra Wide Band (UWB). L’obiettivo del progetto è quindi quello di implementare un sistema di comunicazione punto-multi punto basato su UWB.

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L’obiettivo di questa tesi è riuscire ad elaborare una point cloud 3D proveniente dal laser scanner per individuare possibili ostacoli e creare con essa, successivamente, una mappa che permetta la navigazione di un rover.

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Attraverso lo studio di serie temporali di coordinate è possibile studiare l'entità degli spostamenti, nel tempo, di punti materializzati sulla Terra. In particolare, si incentra l'attenzione sull'analisi della stazione permanente GNSS DCRU collocata presso la base italo-francese Concordia, così da valutare il campo di velocità di deflusso superficiale del ghiaccio in una porzione di plateau dell’Antartide orientale sede della perforazione profonda in ghiaccio del progetto European Project for Ice Coring in Antarctica (EPICA) . Tale stazione è stata inserita in una rete di inquadramento dell'IGS e ha acquisito dati satellitari dal 2005 a oggi, raccolti giornalmente in file RINEX. Tramite l'utilizzo del software Bernese versione 5.2 è stato possibile ottenere dai file RINEX i file SINEX contenenti le soluzioni giornaliere, che costituiscono la serie temporale, e le relative varianze e covarianze. Avvalendosi del programma Tsview implementato per GGMatlab si sono poi valutate le componenti principali che caratterizzano una serie temporale, quali il trend, le componenti stagionali ed i rumori che giocano, talvolta, un ruolo importante nella valutazione dell'incertezza legata alle misure. Infine si è cercato di dare un'interpretazione fisica ai risultati che sono tutt'ora oggetto di studio. In questa tesi, quindi, si delinea un quadro generale delle procedure e delle problematiche da affrontare, sia per ottenere dall'acquisizione satellitare le soluzioni giornaliere costituenti la serie temporale, sia per analizzare la serie stessa.

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The archaeological excavations carried out in 2013 in the hut n. 16 of the protohistoric settlement of Brunku ’e s’Omu (central-western Sardinia) returned some metal products. The morpho-metric and functional study of these artifacts al-lowed the identification of two mending strips and other remains related to Bronze Age (late II millennium BC) ceramic vessels reparing. Some uncertainly dated slags and metal fragments were also identified. Visual examination and archaeometric investigation carried out by means of portable energy dispersive X-ray fluores-cence spectrometry (pXRF) were performed on these metals. The analyses were able to relate some remains to iron manufacturing and highlighted the lead composition of the other ones. The chosen approach further clarified some as-pects of nuragic metallurgists’ behaviour in selecting and processing metalliferous geo-materials.

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The colour of commercial cooked black tiger prawns (Penaeus monodon) is a key quality requirement to ensure product is not rejected in wholesale markets. The colour, due to the carotenoid astaxanthin, can be impacted by frozen storage, but changes in colour or astaxanthin profile, during frozen storage, have not been studied in detail. Subsequently in this study, the aims were to define the astaxanthin (as cis, trans, mono-ester and di-ester forms) content, together with the colour properties, in both pleopods (legs) and abdominal segments. Changes in astaxanthin content and colour properties were further determined during frozen storage (−20°C). Total astaxanthin content was seen to decrease in all samples over time, with the rate of degradation being significantly greater (P < 0.05) in pleopods than abdomen. In both pleopods and abdomen, rate of degradation of esterified forms was significantly greater (P < 0.05) than non-esterified forms. Hue angle (increase), a* value (decrease) and L value (increase) were all seen to significantly change (P < 0.05) during storage, with changes being more prevalent in the pleopods. The pleopods are the key indicator of astaxanthin and colour loss in cooked black tiger prawns and preservation strategies are required to preserve astaxanthin and colour during frozen storage.

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Curatorial considerations, aims and objectives:The title for this exhibition (37 ° South to 19 ° North) refers to the Latitude of Melbourne, Australia and Cuernavaca, Mexico.My curatorial objective for making such a reference to the geographical was to invoke a sense of both distance and connection between the two locations of Australia and Mexico and to also create a sense of sharing, not only between our distant landscapes and cultures but also between the feelings and emotions that we all experience in response to the places in which we live out the moments which make up our daily lives.In developing this project I considered the work of more than 35 contemporary Australian photographers and finally selected 15 photographers (including myself). Most of these artists have or have had close connection to Melbourne and to the southern/eastern line of Australian continent. The final selection ranged from Hobart to Maroochydore and one artist who had lived in Melbourne for many years but was now living in Mexico. These photographers (and the specific works) were selected because their long term creative practice captures a sense of location (place and space) with a deep introspective sensibility which I feel offers a viewer a personal and softly spoken vision of some particular aspect of an Australian location, be that exterior landscape or interior place and a sense of unique connection to such places. These images are not documents but rather representations of feelings, stories, memories and dreams which emerge in the milieu of our inhabitants.In selecting the works, careful consideration was also given to diversity of approaches to photographic practice in conjunction to thematic content. Formats and media included black and white, pin hole photography, toy camera, large format (both 4” x 5” and 10”x 8”), phone camera, various digital camera images and other experimental approaches. The local art scene in Cuernavaca is very strong and there is a strong interest in photography. This is partially due to the number of local arts schools and universities which offer studies in photography as well as the political dimension regarding Mexican art in general - as a tool of both political media, reportage and documentary work, photography is a significant medium for many of the people who would be visiting the exhibition. I therefore felt it was important to address the diversity of approaches to the medium which are currently being explored by Australian practitioners.The City Museum of Cuernavaca provided two large walls and some smaller sections of side walls on both the grounds level and the upper level of the main museum galleries for exhibition.The works were arranged with a simple thematic structure. Top level, left to right, then bottom level, left to right starting with images which presented a sense of wilderness and landscape (which were also quite abstract and reductive) to more representational landscape images moving to landscape with small figures (people) emerging within the images (Ash Kerr) to landscapes with larger figures and the emerging presence of man-made elements to urban landscapes and then to interior urban scapes and finally to interior locations with people and finally finishing on the metaphorical image by Harry Nankin of Bogong Moths and the politics of climate change. (It is also interesting to note that the migration path of the Bongong moth matches well the distribution of the artists selected for this project)Broadly speaking the images started outside with broad landscape to intimate interior locations. With these works a great deal of personal content from each photographer was presented. Most artists chose to present 3 large format images while some only presented 2 images. Other graphic and visual elements were considered in the final placement of the images.It must also be noted that the artists selected ranged broadly from very highly established and significant local artists to mid-career/younger establishing artist to some lesser known and emerging artists. From a curatorial perspective I feel this is offers the possibility of what I shall term, a more balanced representation of the local Australian practice and it provides a context in which both established and emerging artists / works must engage on a dialogue, within the exhibition. I believe it also placing the curatorial premise on the strength of the work rather than on whom the artists are and their status. It also supports the younger emerging artists and provides a less formal and predictable outcome for the established artists and for as a collective presentation as a whole.

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Increasing in resolution of numerical weather prediction models has allowed more and more realistic forecasts of atmospheric parameters. Due to the growing variability into predicted fields the traditional verification methods are not always able to describe the model ability because they are based on a grid-point-by-grid-point matching between observation and prediction. Recently, new spatial verification methods have been developed with the aim of show the benefit associated to the high resolution forecast. Nested in among of the MesoVICT international project, the initially aim of this work is to compare the newly tecniques remarking advantages and disadvantages. First of all, the MesoVICT basic examples, represented by synthetic precipitation fields, have been examined. Giving an error evaluation in terms of structure, amplitude and localization of the precipitation fields, the SAL method has been studied more thoroughly respect to the others approaches with its implementation in the core cases of the project. The verification procedure has concerned precipitation fields over central Europe: comparisons between the forecasts performed by the 00z COSMO-2 model and the VERA (Vienna Enhanced Resolution Analysis) have been done. The study of these cases has shown some weaknesses of the methodology examined; in particular has been highlighted the presence of a correlation between the optimal domain size and the extention of the precipitation systems. In order to increase ability of SAL, a subdivision of the original domain in three subdomains has been done and the method has been applied again. Some limits have been found in cases in which at least one of the two domains does not show precipitation. The overall results for the subdomains have been summarized on scatter plots. With the aim to identify systematic errors of the model the variability of the three parameters has been studied for each subdomain.

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Esta revisión sistemática de la literatura tuvo como objetivo investigar sobre la depresión en personas con epilepsia en la última década (2005-2015), enfocándose en identificar en el paciente con epilepsia: características sociodemográficas, prevalencia de la depresión, tipos de intervención para el manejo de la depresión, factores asociados con la aparición y el mantenimiento de la depresión y por último, identificar las tendencias en investigación en el estudio de la depresión en pacientes con epilepsia. Se revisaron 103 artículos publicados entre 2005 y 2015 en bases de datos especializadas. Los resultados revelaron que la prevalencia de depresión en pacientes con epilepsia es diversa y oscila en un rango amplio entre 3 y 70 %, por otro lado, que las principales características sociodemográficas asociadas a la depresión está el ser mujer, tener un estado civil soltero y tener una edad comprendida entre los 25 y los 45 años. A esto se añade, que los tratamientos conformados por terapia psicológica y fármacos, son la mejor opción para garantizar la eficacia en los resultados del manejo de la depresión en los pacientes con epilepsia. Con respecto a los factores asociados a la aparición de la depresión en pacientes con epilepsia, se identificaron causas tanto neurobiológicas como psicosociales, asimismo los factores principales asociados al mantenimiento fueron una percepción de baja calidad de vida y una baja auto-eficacia. Y finalmente los tipos de investigación más comunes son de tipo aplicado, de carácter descriptivo, transversales y de medición cuantitativa.