221 research outputs found

    Remote Sensing and Local Knowledge of Hydrocarbon Exploitation: The Case of Bovanenkovo, Yamal Peninsula, West Siberia, Russia

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    The capacity of satellite imagery to detect anthropogenic impacts on land cover was assessed for the Bovanenkovo gas field on the Yamal Peninsula in northwest Siberia, which contains some of the world’s largest untapped gas deposits. The region is also the homeland of nomadic Nenets reindeer herders, whose annual migration between the tree line and the northern tundra exposes them to impacts associated with exploration and production activities. These range from physical obstructions, such as roads, railways, and pipelines, to direct and indirect ecological impacts, such as changes in vegetation and hydrology. Nenets’ perceptions of their territories encompass changes in the quantity and quality of terrestrial and freshwater habitats and campsites that have been used seasonally for centuries. Industrial impacts on land cover were examined at spatial scales from very detailed to coarse. Very-high-resolution Quickbird-2 imagery revealed the most impacts, but could not detect items like trash that reduce the quality of reindeer pastures. ASTER, SPOT, and Landsat imagery were useful at the broader landscape level. A proper assessment of the overall ecological impacts of hydrocarbon exploitation requires a combination of remote sensing and detailed ground-truthing. Ideally, these efforts should combine scientific and local knowledge from both indigenous herders and non-indigenous industrial workers.L’aptitude de l’imagerie satellitaire Ă  dĂ©tecter les incidences anthropogĂšnes sur la couverture vĂ©gĂ©tale a Ă©tĂ© Ă©valuĂ©e dans le cas du champ de gaz naturel de Bovanenkovo, dans la pĂ©ninsule de Yamal situĂ©e dans le nord-ouest de la SibĂ©rie oĂč se trouve un des plus grands gisements de gaz inexploitĂ©s du monde. Les NĂ©nĂštses, ou Ă©leveurs de rennes nomades, Ă©voluent dans cette rĂ©gion et leur migration annuelle entre la limite forestiĂšre et la toundra du nord les met en contact avec les travaux d’exploration et de production du gaz. Il peut s’agir d’obstructions physiques prenant la forme de routes, de chemins de fer et de pipelines ou encore, d’incidences Ă©cologiques directes et indirectes touchant notamment la vĂ©gĂ©tation et l’hydrologie. Les perceptions relatives aux territoires des NĂ©nĂštses concernent des changements en matiĂšre de quantitĂ© et de qualitĂ© des habitats terrestres et d’eau douce ainsi que les lieux de campement qui sont utilisĂ©s d’une saison Ă  l’autre depuis des siĂšcles. Les incidences industrielles sur la couverture vĂ©gĂ©tale ont Ă©tĂ© examinĂ©es Ă  diverses Ă©chelles spatiales, allant de trĂšs dĂ©taillĂ©e Ă  grossiĂšre. Les images de trĂšs haute rĂ©solution obtenues au moyen de Quickbird-2 ont permis de rĂ©vĂ©ler le plus grand nombre d’incidences, mais n’ont pas permis de dĂ©tecter des Ă©lĂ©ments tels que les ordures qui avaient pour effet d’amenuiser la qualitĂ© des pĂąturages destinĂ©s aux rennes. Les images obtenues Ă  partir d’ASTER, de SPOT et de Landsat ont Ă©tĂ© utiles au niveau plus vaste du paysage. L’évaluation adĂ©quate des incidences Ă©cologiques gĂ©nĂ©rales dĂ©coulant de l’exploitation des hydrocarbures nĂ©cessite Ă  la fois des outils de tĂ©lĂ©dĂ©tection et le recours Ă  des sites tĂ©moins. IdĂ©alement, ces efforts devraient faire appel tant aux connaissances scientifiques que locales, connaissances provenant des Ă©leveurs indigĂšnes et des travailleurs industriels non-indigĂšnes

    Comparison of Life Calculations for Oscillating Bearings Considering Individual Pitch Control in Wind Turbines

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    The fatigue life calculation of bearings under rotating conditions has been well researched and standardized. In contrast, for bearings in oscillating applications no international standards exist. As a result, pitch bearings in wind turbines are designed with different, non standardized approaches. Furthermore, the impact of individual pitch control on pitch bearings has not yet been studied. In this paper four approaches for fatigue life calculation will be applied and compared under individual pitch control conditions. For comparison, the loads and the bearing geometry of the reference turbine IWT 7.5 MW, which is individual pitch controlled, are used. This paper will show how the bearing life calculated by different approaches reacts to individual pitch control conditions. Furthermore, the factors for the modified rating life, according to the ABMA and ISO standards, which implement different operation conditions on the bearings in rotating applications, are calculated for the given loads and the given bearing geometry in oscillating applications

    Terretonin N: A New Meroterpenoid from Nocardiopsis sp.

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    Hamed A, Abdel-Razek AS, Frese M, et al. Terretonin N: A New Meroterpenoid from Nocardiopsis sp. Molecules. 2018;23(2): 299.Terretonin N (1), a new highly oxygenated and unique tetracyclic 6-hydroxymeroterpenoid, was isolated together with seven known compounds from the ethyl acetate extract of a solid-state fermented culture of Nocardiopsis sp. Their structures were elucidated by spectroscopic analysis. The structure and absolute configuration of 1 were unambiguously determined by X-ray crystallography. The isolation and taxonomic characterization of Nocardiopsis sp. is reported. The antimicrobial activity and cytotoxicity of the strain extract and compound 1 were studied using different microorganisms and a cervix carcinoma cell line, respectively

    Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer

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    Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region's most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species' total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi-faceted role that reindeer exert in Arctic ecosystems

    X-ray photoemission electron microscopy for the study of semiconductor materials

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    Photoemission Electron Microscopy (PEEM) using X-rays is a novel combination of two established materials analysis techniques--PEEM using UV light, and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. This combination allows the study of elemental composition and bonding structure of the sample by NEXAFS spectroscopy with a high spatial resolution given by the microscope. A simple, two lens, 10 kV operation voltage PEEM has been used at the Stanford Synchrotron Radiation Laboratory and at the Advanced Light Source (ALS) in Berkeley to study various problems including materials of interest for the semiconductor industry. In the present paper the authors give a short overview over the method and the instrument which was used, and describe in detail a number of applications. These applications include the study of the different phases of titanium disilicide, various phases of boron nitride, and the analysis of small particles. A brief outlook is given on possible new fields of application of the PEEM technique, and the development of new PEEM instruments

    The diagnostic value of ultrasonography-derived edema of the temporal artery wall in giant cell arteritis: a second meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Ultrasonography of temporal arteries is not commonly used in the approach of patients with suspected giant cell arteritis (GCA) in clinical practice. A meta-analysis of primary studies available through April 2004 concluded that ultrasonography could indeed be helpful in diagnosing GCA. We specifically re-examined the diagnostic value of the ultrasonography-derived halo sign, a dark hypoechoic circumferential thickening around the artery lumen, indicating vasculitic wall edema, in GCA.</p> <p>Methods</p> <p>Original, prospective studies in patients with suspected GCA that examined ultrasonography findings of temporal arteries using the ACR 1990 classification criteria for GCA as reference standard, published through 2009, were identified. Only eight studies involving 575 patients, 204 of whom received the final diagnosis of GCA, fulfilled technical quality criteria for ultrasound. Weighted sensitivity and specificity estimates of the halo sign were assessed, their possible heterogeneity was investigated and pooled diagnostic odds ratio was determined.</p> <p>Results</p> <p>Unilateral halo sign achieved an overall sensitivity of 68% (95% CI, 0.61-0.74) and specificity of 91% (95% CI, 0.88-0.94) for GCA. The values of inconsistency coefficient (I<sup>2</sup>) of both sensitivity and specificity of the halo sign, showed significant heterogeneity concerning the results between studies. Pooled diagnostic odds ratio, expressing how much greater the odds of having GCA are for patients with halo sign than for those without, was 34 (95% CI, 8.21-138.23). Diagnostic odds ratio was further increased to 65 (95% CI, 17.86-236.82) when bilateral halo signs were present (sensitivity/specificity of 43% and 100%, respectively). In both cases, it was found that DOR was constant across studies.</p> <p>Conclusion</p> <p>Temporal artery edema demonstrated as halo sign should be always looked for in ultrasonography when GCA is suspected. Providing that currently accepted technical quality criteria are fulfilled, halo sign's sensitivity and specificity are comparable to those of autoantibodies used as diagnostic tests in rheumatology. Validation of revised GCA classification criteria which will include the halo sign may be warranted.</p

    Unorthodoxy in legislation: The Hungarian experience

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    This paper deals with legal unorthodoxy. The main idea is to study the so-called unorthodox taxes Hungary has adopted in recent years. The study of unorthodox taxes will be preceded by a more general discussion of how law is made under unorthodoxy, and what are the special features of unorthodox legal policy. Unorthodoxy challenges equality before the law and is critical towards mass democracies. It also raises doubts on the operability of the rule of law, relying on personal skills, or loyalty, rather than on impersonal mechanisms arising from checks and balances as developed by the division of political power. Besides, for lack of legal suppositions, legislation suffers from casuistry and regulatory capture

    The anthropology of extraction: critical perspectives on the resource curse

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    Attempts to address the resource curse remain focussed on revenue management, seeking technical solutions to political problems over examinations of relations of power. In this paper, we provide a review of the contribution anthropological research has made over the past decade to understanding the dynamic interplay of social relations, economic interests and struggles over power at stake in the political economy of extraction. In doing so, we show how the constellation of subaltern and elite agency at work within processes of resource extraction is vital in order to confront the complexities, incompatibilities, and inequities in the exploitation of mineral resources
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