588 research outputs found
Ancient harbour infrastructure in the Levant: tracking the birth and rise of new forms of anthropogenic pressure
Beirut, Sidon and Tyre were major centres of maritime trade from the Bronze Age onwards. This economic prosperity generated increased pressures on the local environment, through urbanization and harbour development. Until now, however, the impact of expanding seaport infrastructure has largely been neglected and there is a paucity of data concerning the environmental stresses caused by these new forms of anthropogenic impacts. Sediment archives from Beirut, Sidon and Tyre are key to understanding human impacts in harbour areas because: (i) they lie at the heart of ancient trade networks; (ii) they encompass the emergence of early maritime infrastructure; and (iii) they enable human alterations of coastal areas to be characterized over long timescales. Here we report multivariate analyses of litho- and biostratigraphic data to probe human stressors in the context of their evolving seaport technologies. The statistical outcomes show a notable break between natural and artificial sedimentation that began during the Iron Age. Three anchorage phases can be distinguished: (i) Bronze Age proto-harbours that correspond to natural anchorages, with minor human impacts; (ii) semi-artificial Iron Age harbours, with stratigraphic evidence for artificial reinforcement of the natural endowments; and (iii) heavy human impacts leading to completely artificial Roman and Byzantine harbours
Photometric properties of intermediate-redshift Type Ia supernovae observed by the Sloan Digital Sky Survey-II Supernova Survey
Tsunamis in the geological record: Making waves with a cautionary tale from the Mediterranean
This is the final version of the article. Available from AAAS via the DOI in this record.From 2000 to 2015, tsunamis and storms killed more than 430,000 people worldwide and affected a further >530 million, with total damages exceeding US$970 billion. These alarming trends, underscored by the tragic events of the 2004 Indian Ocean catastrophe, have fueled increased worldwide demands for assessments of past, present, and future coastal risks. Nonetheless, despite its importance for hazard mitigation, discriminating between storm and tsunami deposits in the geological record is one of the most challenging and hotly contended topics in coastal geoscience. To probe this knowledge gap, we present a 4500-year reconstruction of "tsunami" variability from the Mediterranean based on stratigraphic but not historical archives and assess it in relation to climate records and reconstructions of storminess. We elucidate evidence for previously unrecognized "tsunami megacycles" with three peaks centered on the Little Ice Age, 1600, and 3100 cal. yr B.P. (calibrated years before present). These ~1500-year cycles, strongly correlated with climate deterioration in the Mediterranean/North Atlantic, challenge up to 90% of the original tsunami attributions and suggest, by contrast, that most events are better ascribed to periods of heightened storminess. This timely and provocative finding is crucial in providing appropriately tailored assessments of coastal hazard risk in the Mediterranean and beyond.Financial support for this work was provided by Labex OT-Med (ANR-11-LABX-0061). Additional assistance was provided
by the Institut Universitaire de France (CLIMSORIENT project), ANR Geomar (ANR-12-SENV-
0008-01), A*MIDEX (ANR-11-IDEX-0001-02), and Partenariat Hubert Curien PROCOPE
(33361WG). J.G. benefited from a research fellowship at Chrono-environnement funded
by the Région Bourgogne-Franche-Comté
8000 years of coastal changes on a western Mediterranean Island: A multi proxy approach from the Posada plain of Sardinia
A multi-proxy palaeoenvironmental investigation was conducted to reconstruct the Holocene history of coastal landscape change in the lower Posada coastal plain of eastern Sardinia. In this paper, millennial-scale human-sea level-environment interactions are investigated near Posada. Biostratigraphic and palynological approaches were used to interpret the chromo-stratigraphy exhibited by a series of new clothes taken from the coastal plain. This new study elucidates the main palaeoecologiocal changes, phases of shoreline migration and relative sea-level change during the lat 8000 years. The results indicate the major role of sea-level stabilisation and high sediment supply in driving major landscape changes, especially during the Neolithic period (6-4th millennia BC), and the long-term settlement history of this coastal area. It is concluded that human occupation of the coastal plain, from prehistoric to historical times, was most likely constrained by the rapid evolution if this coastal landscape.LR/7 2010 Regione Sardegn
BEAMS: separating the wheat from the chaff in supernova analysis
We introduce Bayesian Estimation Applied to Multiple Species (BEAMS), an
algorithm designed to deal with parameter estimation when using contaminated
data. We present the algorithm and demonstrate how it works with the help of a
Gaussian simulation. We then apply it to supernova data from the Sloan Digital
Sky Survey (SDSS), showing how the resulting confidence contours of the
cosmological parameters shrink significantly.Comment: 23 pages, 9 figures. Chapter 4 in "Astrostatistical Challenges for
the New Astronomy" (Joseph M. Hilbe, ed., Springer, New York, forthcoming in
2012), the inaugural volume for the Springer Series in Astrostatistic
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