35 resultados para lithic artifacts
Resumo:
Egesta of a cave-dwelling mysid (Hemimysis speluncola Ledoyer, 1963) was studied in a submarine cave of Medes Islands, NW Mediterranean by in situ fecal pellet collecting. Fecal pellet production and gut fullness of mysids during incubation experiments are used to estimate mysid egestion rates. Intrinsic factors related with the natural history of this species such as population structure, density of mysids, daily rhythms and pellet decomposition rates are tested for their influence on the egestion rate. The effects of methodological artifacts, such as the stress induced by both incubation and preservation procedures, are also studied. An average mysid egests about 2.5 pellets per day into the cave. The time of day is the main factor affecting egestion. The highest deposition rate is between 2 to 4 hours after sunrise when about 38 % of the total daily pellet production becomes egested. Fecal pellet morphology changes with mysid demographic classes: immature mysids produce slender and thick pellets, whereas mature mysids produce only thick pellets. Immature classes show higher percentages of full guts than mature ones. Mysid density in the incubators does not affect the results on gut fullness, but it causes a decrease in the number of pellets collected after incubation. Coprorhexia seems to be the only plausible process to explain this paradox. The incubation procedure does not increase deposition rate significantly. Time of incubation is critical because the half-life of fecal pellets is about 2.5 hours. Fixation with liquid nitrogen decreases gut fullness and also deposition rates. Higher values are obtained with 70 % ethanol and 5 % formalin solutions which show very similar results for both gut fullness and pellet deposition rates. Nevertheless, ethanol is not suitable as fixative because it enhances the opacity of the body. Several suggestions are given in order to optimize the reliability of further in situ experiments for evaluation of egesta of Hemimysis speluncola in submarine caves.
Resumo:
A very accurate archaeological dating of a Roman site in NE Spain (El Vila-sec) was made based on the typology of pottery artifacts. Three different phases were identifi ed with activity ranging from the mid- 1st century BC to the early-3rd century AD. Analyses of bricks from kilns at El Vila-sec produced data on their stored archaeomagnetic vector. These data were compared with the secular variation curve for the Iberian Peninsula and the SCHA.DIF.3K regional archaeomagnetic model. Both, the reference curve and the model, produced probability distributions for the final period of use for two kilns from the second archaeological phase that were not used during the third phase. At a 95% con fidence level, both time distributions cover a wide chronological range including the presumed archaeological age. Both the Iberian secular variation curve and the SCHA.DIF.3K regional model proved to be suitable models for dating the site, although on their own they do not produce a single unambiguous solution. This archaeomagnetic approach could also be applied to neighbouring archaeological sites that have an imprecise archaeological age.
Resumo:
Artifacts are present in most of the electroencephalography (EEG) recordings, making it difficult to interpret or analyze the data. In this paper a cleaning procedure based on a multivariate extension of empirical mode decomposition is used to improve the quality of the data. This is achieved by applying the cleaning method to raw EEG data. Then, a synchrony measure is applied on the raw and the clean data in order to compare the improvement of the classification rate. Two classifiers are used, linear discriminant analysis and neural networks. For both cases, the classification rate is improved about 20%.
Resumo:
El objetivo del artículo es presentar las bases teóricas y conceptuales de una disciplina a medio camino entre la psicología, la geografía y la antropología: la “psicogeografía cultural del desarrollo humano” (PCDH). Entendiendo por PCDH el estudio del desarrollo psicológico humano dentro de ciertas “geografías vitales y psicológicas” como un río, montaña o valle; una institución social como la escuela o la familia; ciertos artefactos como una bandera, un libro o un mapa; ideologías como el nacionalismo o liberalismo; relaciones sociales entre, por ejemplo, padre e hijo y ciertas actividades realizadas
Resumo:
In this paper, an advanced technique for the generation of deformation maps using synthetic aperture radar (SAR) data is presented. The algorithm estimates the linear and nonlinear components of the displacement, the error of the digital elevation model (DEM) used to cancel the topographic terms, and the atmospheric artifacts from a reduced set of low spatial resolution interferograms. The pixel candidates are selected from those presenting a good coherence level in the whole set of interferograms and the resulting nonuniform mesh tessellated with the Delauney triangulation to establish connections among them. The linear component of movement and DEM error are estimated adjusting a linear model to the data only on the connections. Later on, this information, once unwrapped to retrieve the absolute values, is used to calculate the nonlinear component of movement and atmospheric artifacts with alternate filtering techniques in both the temporal and spatial domains. The method presents high flexibility with respect to the required number of images and the baselines length. However, better results are obtained with large datasets of short baseline interferograms. The technique has been tested with European Remote Sensing SAR data from an area of Catalonia (Spain) and validated with on-field precise leveling measurements.
Resumo:
The main goal of this article is to illustrate a way of detecting identity foundations in people using extended autobiographical multi-methodology as a qualitative approach that combines different techniques to study the narrative construction of identity. There are four groups of techniques: 1) in-depth interviews; 2) the revised self-portrait technique; 3) the analysis of artifacts, routines and ways of living, and 4) “psycho-geographical maps.” “Identity foundations” are understood as a set of resources (toolbox) that have been historicallyaccumulated, culturally developed and socially distributed and transmitted, which are essential for defining and presenting oneself. Two examples are provided that illustrate how to use this methodological approach to achieve the aforementioned objective. In conclusion, the study recommends taking into account the explicit and implicit, underlying cultural forces involved in constructing human identity
Resumo:
Relief Mapping is giving great results for the creation of 3D impostor models. An impostor model is a simplication of an original geometric model that is used to replace it. Then, the original volume can be reproduced in a high quality representation with very few artifacts or cracks and a high compactness. We have studied the state of the art on Relief Impostors and some current techniques related to them. In particular, we have implemented the Omni-directional Relief Impostors (ORI) technique and its hierarchical extension (HORI), througn the usage of spatial partition methods. We expose an alternative to the spatial distribution and selection of the impostors. Furthermore, we show a different computation for the rendering view distance in order to guarantee a minimal quality for the simplified representation. Finally, we discuss the obtained results and propose some new ideas or approaches to enhance the efficiency and quality of the final rendering using ORIs' and HORIs' techniques. In addition, our implementation has involved a software engineering study in the Open Source field.
Resumo:
During the fieldwork in the medieval fortification of Ausa (Gipuzkoa), a vast amount of sherds from several pottery artifacts featured by a cylindrical body has been found out. They presumably had the same function in contexts dated from the first half of xiv century. Although it has not been possible to reconstruct any of these artefacts, the study of the sherds allows us to think that they would have formed some sort of big-sized horn. This high-sounding instrument, which has been frequently reproduced in iconographic references, does not have at this moment any direct parallelism in Hispanic contexts, despite being plentiful of references to similar objects in medieval ranges from Provence and Languedoc. By introducing these artefacts from different approaches, we aim to go over the scarce knowledge of these instruments, whose evidence lets us to believe in their widespread distribution all over the landscape in several material contexts from Medieval Ages.
Resumo:
During the fieldwork in the medieval fortification of Ausa (Gipuzkoa), a vast amount of sherds from several pottery artifacts featured by a cylindrical body has been found out. They presumably had the same function in contexts dated from the first half of xiv century. Although it has not been possible to reconstruct any of these artefacts, the study of the sherds allows us to think that they would have formed some sort of big-sized horn. This high-sounding instrument, which has been frequently reproduced in iconographic references, does not have at this moment any direct parallelism in Hispanic contexts, despite being plentiful of references to similar objects in medieval ranges from Provence and Languedoc. By introducing these artefacts from different approaches, we aim to go over the scarce knowledge of these instruments, whose evidence lets us to believe in their widespread distribution all over the landscape in several material contexts from Medieval Ages.
Resumo:
The question of whether symbolically mediated behavior is exclusive to modern humans or shared with anatomically archaic populations such as the Neandertals is hotly debated. At the Grotte du Renne, Arcy-sur-Cure, France, the Châtelperronian levels contain Neandertal remains and large numbers of personal ornaments, decorated bone tools and colorants, but it has been suggested that this association reflects intrusion of the symbolic artifacts from the overlying Protoaurignacian and/or of the Neandertal remains from the underlying Mousterian.
Resumo:
Systems made of parts that are totally connected do not work, neither ecosys- tems nor artifacts. Relative connectance is inversely related to diversity, and both magnitudes can find a common frame of expression, in which some constant expressing the constraints of any organization might be embodied. If S is Simp- son's index, the expression (1 - S)IS as a measure of diversity offers some advantages or, at least, helps further reasoning. Such expression is the ratio between total interspecific possible interactions and possible intraspecific inter- actions.
Resumo:
The CORNISH project is the highest resolution radio continuum survey of the Galactic plane to date. It is the 5 GHz radio continuum part of a series of multi-wavelength surveys that focus on the northern GLIMPSE region (10° < l < 65°), observed by the Spitzer satellite in the mid-infrared. Observations with the Very Large Array in B and BnA configurations have yielded a 1.''5 resolution Stokes I map with a root mean square noise level better than 0.4 mJy beam 1. Here we describe the data-processing methods and data characteristics, and present a new, uniform catalog of compact radio emission. This includes an implementation of automatic deconvolution that provides much more reliable imaging than standard CLEANing. A rigorous investigation of the noise characteristics and reliability of source detection has been carried out. We show that the survey is optimized to detect emission on size scales up to 14'' and for unresolved sources the catalog is more than 90% complete at a flux density of 3.9 mJy. We have detected 3062 sources above a 7σ detection limit and present their ensemble properties. The catalog is highly reliable away from regions containing poorly sampled extended emission, which comprise less than 2% of the survey area. Imaging problems have been mitigated by down-weighting the shortest spacings and potential artifacts flagged via a rigorous manual inspection with reference to the Spitzer infrared data. We present images of the most common source types found: H II regions, planetary nebulae, and radio galaxies. The CORNISH data and catalog are available online at http://cornish.leeds.ac.uk.
Resumo:
This work investigates performance of recent feature-based matching techniques when applied to registration of underwater images. Matching methods are tested versus different contrast enhancing pre-processing of images. As a result of the performed experiments for various dominating in images underwater artifacts and present deformation, the outperforming preprocessing, detection and description methods are proposed
Resumo:
[spa] En el presente artículo se presentan los tres grandes ámbitos en los que se desarrolla la investigación arqueométrica sobre cerámicas: la identificación de los materiales, la proveniencia de los artefactos y la tecnología en la que se inscriben. El artículo hace una incidencia especial en aquello que se entiende por tecnología, indicando que la tecnología de producción es únicamente una parte de la misma, y que el concepto básico es el de diseño, que debe adecuarse a una multiplicidad de características de desempeño, explicadas por la cadena conductual en la cual transcurre la vida de los artefactos. Dado que las culturas se expresan por medio de artefactos, la vertiente material de éstos refleja, aunque sólo sea en parte, los compromisos que dichos artefactos tienen en las culturas en estudio. La arqueometría, con un cuerpo teórico y metodológico adaptado a la investigación de esta vertiente natural de los artefactos, aparece así como una forma complementaria de hacer arqueología y no como un campo de estudio diferenciado.
Resumo:
A capillary microtrap thermal desorption module is developed for near real-time analysis of volatile organic compounds (VOCs) at sub-ppbv levels in air samples. The device allows the direct injection of the thermally desorbed VOCs into a chromatographic column. It does not use a second cryotrap to focalize the adsorbed compounds before entering the separation column so reducing the formation of artifacts. The connection of the microtrap to a GC–MS allows the quantitative determination of VOCs in less than 40 min with detection limits of between 5 and 10 pptv (25 °C and 760 mmHg), which correspond to 19–43 ng m−3, using sampling volumes of 775 cm3. The microtrap is applied to the analysis of environmental air contamination in different laboratories of our faculty. The results obtained indicate that most volatile compounds are easily diffused through the air and that they also may contaminate the surrounding areas when the habitual safety precautions (e.g., working under fume hoods) are used during the manipulation of solvents. The application of the microtrap to the analysis of VOCs in breath samples suggest that 2,5-dimethylfuran may be a strong indicator of a person's smoking status