164 research outputs found

    La radiación externa controlada como técnica de potenciación de las señales registradas con la termografía infrarroja

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    Infrared thermography is a very versatile non destructive technique which among other uses, can be applied to the study of moisture in buildings. However, this particular application can present some problems strictly related to the characteristics of the thermocamera device. In this case the available equipment works in the IR range of 2.5 to 5.6 μm. In this part of the spectrum, there exists a small and not very intense band of emission of the water molecules (approximately centered at 2.7 μm), in such a way that detection can be difficult through thermovision. In the present paper, a complementary technique to the IR thermography being able of favouring the emission of water on the mentioned band, has been developed. It enhances the capacity of detection of the instrument. Likewise, the process which takes place in the material has been numerically modelled.La termografía infrarroja es una técnica no destructiva, muy versátil, que, entre otras aplicaciones, tiene la de ser capaz de suministrar información en torno a la problemática de las humedades en la edificación. Sin embargo, esta aplicación concreta puede presentar algunos problemas directamente relacionados con las propias características de la termocámara utilizada. En el caso del presente trabajo el equipo de termografía infrarroja manejado trabaja en el rango del espectro IR comprendido entre 2,5 y 5,6 μm. En esta región del espectro existe una pequeña y no muy intensa banda de emisión de las moléculas de agua (aproximadamente centrada en 2,7 μm) cuya detección puede no ser fácil a través de la termovisión. En el presente trabajo se ha desarrollado una técnica complementaria a la termografía infrarroja que es capaz de favorecer la intensidad de emisión del agua en la región del espectro antes mencionada. En definitiva, dicha técnica estimula la capacidad de detección de la termocámara. Adicionalmente, el proceso hídrico que tiene lugar en el material ha sido numéricamente modelizado

    Tumores en ganado ovino sacrificado en matadero

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    Trabajo presentado al: XL Congreso Nacional y el XVI Congreso Internacional de la Sociedad Española de Ovinotecnia y Caprinotecnia. (Castellón de la Plana, España, 16-18 septiembre 2015).Peer Reviewe

    Increasing social complexity, climate change, and why societies might fail to cope

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    The PEOPLE 3000 working group focuses on integrating archaeological and paleoecological case studies with mathematical modeling. We seek to understand how coevolving human societies and ecosystems can successfully cope with the interrelated forces of population growth, increasing social complexity and climate change, and the diversity of trajectories of reorganization that social-ecological systems follow.Fil: Byers, David A.. State University of Utah; Estados UnidosFil: Lima, M.. State University of Utah; Estados UnidosFil: Gil, Adolfo Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Universidad Tecnologica Nacional. Facultad Regional San Rafael; ArgentinaFil: Gayo, E.. Pontificia Universidad Católica de Chile; ChileFil: Latorre, C.. Pontificia Universidad Católica de Chile; ChileFil: Robinson, Erick. University Of Wyoming; Estados UnidosFil: Villalba, R.. Universidad Tecnologica Nacional. Facultad Regional San Rafael; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

    Presencia de infección y lesiones mínimas en mama y otros tejidos en ovinos afectados de Maedi-Visna

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    5 páginas, 2 tablas.--Trabajo presentado al: XL Congreso Nacional y el XVI Congreso Internacional de la Sociedad Española de Ovinotecnia y Caprinotecnia. (Castellón de la Plana, España, 16-18 septiembre 2015).Este trabajo ha sido subvencionado por los proyectos LE361A12-1 y LE314U14 de la Junta de Castilla y León y por una beca FPU del Ministerio de Educación.Peer Reviewe

    Musical preferences and technologies: Contemporary material and symbolic distinctions criticised

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    Today how individuals interact with various cultural items is not perfectly consistent with theoretical frameworks of influential scholars on cultural consumption, such as Bourdieu (1984), Gans (1999), and Peterson and Simkus (1992). One such variation is in the ever increasing variety of technological modes to acquire and listen to music (Pinch and Bijsterveld, 2004). However, as a consequence of digital divides (van Dijk, 2006), technological items may not be distributed equally among social groups. At present, the value of status-making through a preference for different genres of music extends itself to different forms of consumption and ways of experiencing music. We are yet to fully understand the power these practices have on generating status. This article is therefore motivated by the need to integrate within quantitative frameworks of taste and cultural consumption, an analysis of individuals’ technological engagement. These two dimensions, integrated as components of musical practices, enhance our understanding of cultural boundaries across different social groups.The objective is to bridge a gap detected in the literature, addressing the following questions: Are technological modes to listen to music related to musical tastes

    Hydroclimate variability in the low-elevation Atacama Desert over the last 2500 yr

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    Paleoclimate reconstructions reveal that Earth system has experienced sub-millennial scale climate changes over the past two millennia in response to internal/external forcing. Although sub-millennial hydroclimate fluctuations have been detected in the central Andes during this interval, the timing, magnitude, extent and direction of change of these events remain poorly defined. Here, we present a reconstruction of hydroclimate variations on the Pacific slope of the central Andes based on exceptionally well-preserved plant macrofossils and associated archaeological remains from a hyperarid drainage (Quebrada Maní, ∼21° S, 1000 m a.s.l.) in the Atacama Desert. During the late Holocene, riparian ecosystems and farming social groups flourished in the hyperarid Atacama core as surface water availability increased throughout this presently sterile landscape. Twenty-six radiocarbon dates indicate that these events occurred between 1050–680, 1615–1350 and 2500–2040 cal yr BP. Regional comparisons with rodent middens and other records suggest that these events were synchronous with pluvial stages detected at higher-elevations in the central Andes over the last 2500 yr. These hydroclimate changes also coincide with periods of pronounced SST gradients in the Tropical Pacific (La Niña-like mode), conditions that are conducive to significantly increased rainfall in the central Andean highlands and flood events in the low-elevation watersheds at inter-annual timescales. Our findings indicate that the positive anomalies in the hyperarid Atacama over the past 2500 yr represent a regional response of the central Andean climate system to changes in the global hydrological cycle at centennial timescales. Furthermore, our results provide support for the role of tropical Pacific sea surface temperature gradient changes as the primary mechanism responsible for climate fluctuations in the central Andes. Finally, our results constitute independent evidence for comprehending the major trends in cultural evolution of prehistoric peoples that inhabited the region

    A meta-analysis of state-of-the-art electoral prediction from Twitter data

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    Electoral prediction from Twitter data is an appealing research topic. It seems relatively straightforward and the prevailing view is overly optimistic. This is problematic because while simple approaches are assumed to be good enough, core problems are not addressed. Thus, this paper aims to (1) provide a balanced and critical review of the state of the art; (2) cast light on the presume predictive power of Twitter data; and (3) depict a roadmap to push forward the field. Hence, a scheme to characterize Twitter prediction methods is proposed. It covers every aspect from data collection to performance evaluation, through data processing and vote inference. Using that scheme, prior research is analyzed and organized to explain the main approaches taken up to date but also their weaknesses. This is the first meta-analysis of the whole body of research regarding electoral prediction from Twitter data. It reveals that its presumed predictive power regarding electoral prediction has been rather exaggerated: although social media may provide a glimpse on electoral outcomes current research does not provide strong evidence to support it can replace traditional polls. Finally, future lines of research along with a set of requirements they must fulfill are provided.Comment: 19 pages, 3 table

    Ecology of the collapse of Rapa Nui society

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    Collapses of food producer societies are recurrent events in prehistory and have triggered a growing concern for identifying the underlying causes of convergences/divergences across cultures around the world. One of the most studied and used as a paradigmatic case is the population collapse of the Rapa Nui society. Here, we test different hypotheses about it by developing explicit population dynamic models that integrate feedbacks between climatic, demographic and ecological factors that underpinned the sociocultural trajectory of these people. We evaluate our model outputs against a reconstruction of past population size based on archaeological radiocarbon dates from the island. The resulting estimated demographic declines of the Rapa Nui people are linked to the long-term effects of climate change on the island's carrying capacity and, in turn, on the 'per-capita food supply'

    Beating the news using social media: the case study of American Idol

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    We present a contribution to the debate on the predictability of social events using big data analytics. We focus on the elimination of contestants in the American Idol TV shows as an example of a well defined electoral phenomenon that each week draws millions of votes in the USA. This event can be considered as basic test in a simplified environment to assess the predictive power of Twitter signals. We provide evidence that Twitter activity during the time span defined by the TV show airing and the voting period following it correlates with the contestants ranking and allows the anticipation of the voting outcome. Twitter data from the show and the voting period of the season finale have been analyzed to attempt the winner prediction ahead of the airing of the official result. We also show that the fraction of tweets that contain geolocation information allows us to map the fanbase of each contestant, both within the US and abroad, showing that strong regional polarizations occur. The geolocalized data are crucial for the correct prediction of the final outcome of the show, pointing out the importance of considering information beyond the aggregated Twitter signal. Although American Idol voting is just a minimal and simplified version of complex societal phenomena such as political elections, this work shows that the volume of information available in online systems permits the real time gathering of quantitative indicators that may be able to anticipate the future unfolding of opinion formation events
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