294 research outputs found

    The failed liberalisation of Algeria and the international context: a legacy of stable authoritarianism

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    The paper attempts to challenge the somewhat marginal role of international factors in the study of transitions to democracy. Theoretical and practical difficulties in proving causal mechanisms between international variables and domestic outcomes can be overcome by defining the international dimension in terms of Western dominance of world politics and by identifying Western actions towards democratising countries. The paper focuses on the case of Algeria, where international factors are key in explaining the initial process of democratisation and its following demise. In particular, the paper argues that direct Western policies, the pressures of the international system and external shocks influence the internal distribution of power and resources, which underpins the different strategies of all domestic actors. The paper concludes that analysis based purely on domestic factors cannot explain the process of democratisation and that international variables must be taken into more serious account and much more detailed

    The Roman centuriated landscape: conception, genesis and development as inferred from the Ager Tarraconensis case

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    Although centuriation was only one system of Roman land division, its impact on the landscape and its visibility in modern field arrangements make it the most commonly recognized expression of Roman landscapes. Centuriated grid systems are usually analyzed from a materialistic point of view and consequently regarded as an assertion of Roman dominance over conquered territories. In this sense, their productive function is clear. The hinterland of Tarraco (the ancient capital of the Roman province of Tarraconensis) offers one of the most clearly documented examples of multiple-grid centuriated systems. From 2006 to 2010, the Landscape Archaeology Research Group (GIAP) of the Catalan Institute of Classical Archaeology employed a wide array of digital and field methodologies at Tarraco to record the traces of centuriated land divisions and their Roman origin. Most importantly, these methods have allowed research to move beyond pure description of the traces to explore the concepts and ideas behind the making of a centuriated landscape. By using Tarraco as a case study, this article shows how centuriation was not only a system for dividing the land but also a conceptual appropriation of the landscape based on a strong mythical and religious backgroun

    Towards take-all control:A C-‐21β oxidase required for acylation of triterpene defence compounds in oat

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    Oats produce avenacins, antifungal triterpenes that are synthesized in the roots and provide protection against take-all and other soilborne diseases. Avenacins are acylated at the carbon-21 position of the triterpene scaffold, a modification critical for antifungal activity. We have previously characterized several steps in the avenacin pathway, including those required for acylation. However, transfer of the acyl group to the scaffold requires the C-21β position to be oxidized first, by an as yet uncharacterized enzyme. We mined oat transcriptome data to identify candidate cytochrome P450 enzymes that may catalyse C-21β oxidation. Candidates were screened for activity by transient expression in Nicotiana benthamiana. We identified a cytochrome P450 enzyme AsCYP72A475 as a triterpene C-21β hydroxylase, and showed that expression of this enzyme together with early pathway steps yields C-21β oxidized avenacin intermediates. We further demonstrate that AsCYP72A475 is synonymous with Sad6, a previously uncharacterized locus required for avenacin biosynthesis. sad6 mutants are compromised in avenacin acylation and have enhanced disease susceptibility. The discovery of AsCYP72A475 represents an important advance in the understanding of triterpene biosynthesis and paves the way for engineering the avenacin pathway into wheat and other cereals for control of take-all and other diseases

    Aurès

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    Préhistoire (E.B.) Les recherches préhistoriques demeurent encore au stade de la prospection dans l’ensemble de l’Aurès. Un seul gisement connu depuis le début du siècle, a fait l’objet d’une fouille moderne : la grotte du Khanguet Si Mohamed Tahar (connue aussi sous le nom de grotte Cappeletti), encore est-elle située sur le versant nord du massif, surplombant le bassin de Timgad. Ce gisement a servi à définir un faciès du Néolithique de tradition capsienne (C. Roubet, 1979). Cependant l’occ..

    Combined Characterisation of GOME and TOMS Total Ozone Using Ground-Based Observations from the NDSC

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    Several years of total ozone measured from space by the ERS-2 GOME, the Earth Probe Total Ozone Mapping Spectrometer (TOMS), and the ADEOS TOMS, are compared with high-quality ground-based observations associated with the Network for the Detection of Stratospheric Change (NDSC), over an extended latitude range and a variety of geophysical conditions. The comparisons with each spaceborne sensor are combined altogether for investigating their respective solar zenith angle (SZA) dependence, dispersion, and difference of sensitivity. The space- and ground-based data are found to agree within a few percent on average. However, the analysis highlights for both Global Ozone Monitoring Experiment (GOME) and TOMS several sources of discrepancies, including a dependence on the SZA at high latitudes and internal inconsistencies

    Using synthetic biological parts and microbioreactors to explore the protein expression characteristics of Escherichia coli

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    Synthetic biology has developed numerous parts for the precise control of protein expression. However, relatively little is known about the burden these place on a host, or their reliability under varying environmental conditions. To address this, we made use of synthetic transcriptional and translational elements to create a combinatorial library of constructs that modulated expression strength of a green fluorescent protein. Combining this library with a microbioreactor platform, we were able to perform a detailed large-scale assessment of transient expression and growth characteristics of two <i>Escherichia coli</i> strains across several temperatures. This revealed significant differences in the robustness of both strains to differing types of protein expression, and a complex response of transcriptional and translational elements to differing temperatures. This study supports the development of reliable synthetic biological systems capable of working across different hosts and environmental contexts. Plasmids developed during this work have been made publicly available to act as a reference set for future research

    Technical Note: New ground-based FTIR measurements at Ile de La Réunion: observations, error analysis, and comparisons with independent data

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    Ground-based high spectral resolution Fourier-transform infrared (FTIR) solar absorption spectroscopy is a powerful remote sensing technique to obtain information on the total column abundances and on the vertical distribution of various constituents in the atmosphere. This work presents results from two FTIR measurement campaigns in 2002 and 2004, held at Ile de La Réunion (21° S, 55° E). These campaigns represent the first FTIR observations carried out at a southern (sub)tropical site. They serve the initiation of regular, long-term FTIR monitoring at this site in the near future. To demonstrate the capabilities of the FTIR measurements at this location for tropospheric and stratospheric monitoring, a detailed report is given on the retrieval strategy, information content and corresponding full error budget evaluation for ozone (O3), methane (CH4), nitrous oxide (N2O), carbon monoxide (CO), ethane (C2H6), hydrogen chloride (HCl), hydrogen fluoride (HF) and nitric acid (HNO3) total and partial column retrievals. Moreover, we have made a thorough comparison of the capabilities at sea level altitude (St.-Denis) and at 2200 m a.s.l. (Maïdo). It is proved that the performances of the technique are such that the atmospheric variability can be observed, at both locations and in distinct altitude layers. Comparisons with literature and with correlative data from ozone sonde and satellite (i.e., ACE-FTS, HALOE and MOPITT) measurements are given to confirm the results. Despite the short time series available at present, we have been able to detect the seasonal variation of CO in the biomass burning season, as well as the impact of particular biomass burning events in Africa and Madagascar on the atmospheric composition above Ile de La Réunion. We also show that differential measurements between St.-Denis and Maïdo provide useful information about the concentrations in the boundary layer.Peer reviewe
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