57 research outputs found
Paleoseismic History of the Dead Sea Fault Zone
International audienceThe aim of this entry is to describe the DSF as a transform plate boundary pointing out the rate of activedeformation, fault segmentation, and geometrical complexities as a control of earthquake ruptures. Thedistribution of large historical earthquakes from a revisited seismicity catalogue using detailedmacroseismic maps allows the correlation between the location of past earthquakes and fault segments.The recent results of paleoearthquake investigations (paleoseismic and archeoseismic) with a recurrenceinterval of large events and long-term slip rate are presented and discussed along with the identification ofseismic gaps along the fault. Finally, the implications for the seismic hazard assessment are also discussed
Archaeoseismology: Methodological issues and procedure
Archaeoseismic research contributes important data on past earthquakes. A limitation of the usefulness of archaeoseismology is due to the lack of continuous discussion about the methodology. The methodological issues are particularly important because archaeoseismological investigations of past earthquakes make use of a large variety of methods. Typical in situ investigations include: (1) reconstruction of the local archaeological stratigraphy aimed at defining the correct position and chronology of a destruction layer, presumably related to an earthquake; (2) analysis of the deformations potentially due to seismic shaking or secondary earthquake effects, detectable on walls; (3) analysis of the depositional characteristics of the collapsed material; (4) investigations of the local geology and geomorphology to define possible natural cause(s) of the destruction; (5) investigations of the local factors affecting the ground motion amplifications; and (6) estimation of the dynamic excitation, which affected the site under investigation. Subsequently, a 'territorial' approach testing evidence of synchronous destruction in a certain region may delineate the extent of the area struck by the earthquake. The most reliable results of an archaeoseismological investigation are obtained by application of modern geoarchaeological practice (archaeological stratigraphy plus geological–geomorphological data), with the addition of a geophysical-engineering quantitative approach and (if available) historical information. This gives a basic dataset necessary to perform quantitative analyses which, in turn, corroborate the archaeoseismic hypothesis. Since archaeoseismological investigations can reveal the possible natural causes of destruction at a site, they contribute to the wider field of environmental archaeology, that seeks to define the history of the relationship between humans and the environment. Finally, through the improvement of the knowledge on the past seismicity, these studies can contribute to the regional estimation of seismic hazard
Realising consilience: How better communication between archaeologists, historians and natural scientists can transform the study of past climate change in the Mediterranean
This paper reviews the methodological and practical issues relevant to the ways in which natural scientists, historians and archaeologists may collaborate in the study of past climatic changes in the Mediterranean basin. We begin by discussing the methodologies of these three disciplines in the context of the consilience debate, that is, attempts to unify different research methodologies that address similar problems. We demonstrate that there are a number of similarities in the fundamental methodology between history, archaeology, and the natural sciences that deal with the past (“palaeoenvironmental sciences”), due to their common interest in studying societal and environmental phenomena that no longer exist. The three research traditions, for instance, employ specific narrative structures as a means of communicating research results. We thus present and compare the narratives characteristic of each discipline; in order to engage in fruitful interdisciplinary exchange, we must first understand how each deals with the societal impacts of climatic change. In the second part of the paper, we focus our discussion on the four major practical issues that hinder communication between the three disciplines. These include terminological misunderstandings, problems relevant to project design, divergences in publication cultures, and differing views on the impact of research. Among other recommendations, we suggest that scholars from the three disciplines should aim to create a joint publication culture, which should also appeal to a wider public, both inside and outside of academia.This paper emerged as a result of a workshop at Costa Navarino and the Navarino Environmental Observatory (NEO), Greece in April 2014, which addressed Mediterranean Holocene climate and human societies. The workshop was co-sponsored by IGBP/PAGES, NEO, the MISTRALS/PaleoMex program, the Labex OT-Med, the Bolin Centre for Climate Research at Stockholm University, and the Institute of Oceanography at the Hellenic Centre for Marine Research. We also acknowledge funding from the National Science Centre, Poland, within the scheme of the Centre's postdoctoral fellowships (DEC-2012/04/S/HS3/00226 (A.I)); the Swedish Research Council (grant numbers 421-2014-1181 (E.W.) and 621-2012-4344 (K.H.)); CSIC-Ramón y Cajal post-doctoral program RYC-2013-14073 and Clare Hall College, Cambridge, Shackleton Fellowship (B.M.); the EU/FP7 Project ‘Sea for Society’ (Science and Society - 2011-1, 289066)
The Nile: its role in the fortunes and misfortunes of the Fatimid dynasty during its rule of Egypt (969-1171)
The epoch spanning the years 935-1094 constitutes - on the whole - the longest and driest period on record in the history of the Nile. A stretch of relatively normal discharge followed this phase, only for dryness to return. The reasons of this dry-wet-dry phenomenon have been recently appraised in the context of global climatic changes – the so-called “Medieval Warm Period” - that affected most of the known world between the 11th and the 13th centuries. It was in this period of Egyptian history that the Shi‘i Isma‘ili Fatimids replaced the Sunni Ikhshidids as rulers in 358/969 and, with alternating fortunes, continued to reign until 567/1171.
In this paper, I examine how, faced with the convergence of extraordinary geo-climatic factors, the Fatimids managed (and mismanaged) the Nile and its valley. I contend that the imperial aspirations of the Fatimids in Cairo and beyond were in many ways subject to the typical unpredictability of the natural cycles of the river, hence the Fatimids’ success and failure in managing the varied economic, political and trading activities that took place along the Egyptian section of the Nile valley. A case in point highlighted here will be the Fatimids’ privileging of flax cultivation over wheat
Archeoseismic study of damage in Roman and Medieval structures in the center of Cologne, Germany
Resting-state functional connectivity of orthographic networks in acquired dysgraphia
Introduction.
While task-based fMRI has been used extensively to study the functional neural networks that instantiate cognitive functions, there is increasing interest in analyzing the activity of the brain while it is not performing a task – in the resting state (RS). In RS-fMRI, participants lie in a relaxed awake state during fMRI scanning, and correlations of the activation time-series between their different brain areas are analyzed. These analyses have revealed many of the same networks identified in task-based fMRI, including the default-mode network (DMN), the dorsal attention network, the motor network, etc. Various network properties have been studied; for example, some networks have stronger correlations between the nodes of the same network (to which we refer as “within-network coherence”), than between nodes from different networks (“across-network coherence”), resulting in clustering of network nodes (e.g., Cole et al., 2014).
There has been great interest in understanding how RS network connectivity may be affected by brain illness or injury (e.g., Finn et al., 2014, Park et al., 2011). However, one domain that has received scarce attention even in studies with neuro-typical individuals is orthographic processing (reading and spelling). We report on a study that examines the orthographic processing network (OPN) in neuro-typical individuals and in individuals with acquired dysgraphia subsequent to stroke, examining how this network can be affected by brain injury and how it responds to rehabilitation. Specifically, we examine the possibility that rehabilitation may lead to normalization of RS network connectivity such that the properties of the damaged network increasingly resemble those of intact networks.
Methods.
Participants are eight neuro-typical adults (NTA), and three adults with left-hemisphere stroke and acquired dysgraphia. NTAs had two RS-fMRI scans in the same session; dysgraphics had one scan, followed by 2-4 months of spelling rehabilitation, and two more scans. Regions of interest (ROIs) were identified using coordinates of the OPN (Turkeltaub et al., 2001) and the DMN (Laird et al., 2009). Within-network coherence corresponded to the average RS-fMRI correlations between every pair of ROIs within each network; across-network coherence was the average correlation between every pair of ROIs from the two different networks (Song et al., 2011).
Results (Figure 1).
(1) Each NTA showed stronger within-network coherence for the OPN than across-network coherence between OPN and DMN. (2) Before treatment, two of the dysgraphics showed weaker within-network coherence for the OPN than across-network coherence between OPN and DMN. Following treatment all three dysgraphics showed the same network coherence pattern as the NTAs.
Discussion.
The NTA findings indicate that the relationship between orthographic and default-mode networks is characterized by greater within- vs. across-network connectivity. Furthermore, we show for the first time a pattern of increasing within/across network “coherence normalization” following spelling rehabilitation. Additional dysgraphic participants and other networks (language, sensory-motor, etc.) will be analyzed to develop a better understanding of the RS orthographic network and its response to damage and recovery.
Acknowledgements.
The work is part of a multi-site, NIDCD-supported project examining language recovery neurobiology in aphasia (DC006740). We thank Melissa Greenberger and Xiao-Wei Song
Frankish Rural Settlement in the Latin Kingdom of Jerusalem /
Title from publisher's bibliographic system (viewed on 25 Nov 2014)
Medieval Climate in the Eastern Mediterranean: Instability and Evidence of Solar Forcing
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