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1.
This paper is about ‘material politics’. It argues that this may be understood as a material ordering of the world in a way that contrasts this with other and equally possible alternative modes of ordering. It also suggests that while material politics may well involve words, it is not discursive in kind. This argument is made for the mundane and material practice of boiling pigswill that the 2001 UK foot and mouth outbreak showed to have a layered importance. Boiling pigswill was a political technique in at least three different ways. First it made difference, dividing the rich from the poor by separating disease free countries from those in which foot and mouth is endemic. Second, it joined times and places by linking past agricultural practices with those of the contemporary world, and linking Britain with the world. And third, it also showed a way of limiting food scarcity on a world wide scale because it allowed food to be recycled, albeit on a small scale, in a region of plenty. ‘Politics’ is often linked to debate, discussion, or explicit contestation. Alternatively, it is sometimes seen as being embedded in and carried by artefacts. For the case of boiling pigswill neither approach is satisfactory. The first privileges the life of the mind while in the second politics is linked too strongly to a single order. The version of politics presented here foregrounds both materiality and difference. And it involves articulation: the question is not whether something is political all by itself but whether it can be called political as part of the process of analysing it. 相似文献
2.
Multi-proxy evidence of long-term changes in ecosystem structure in a Danish marine estuary, linked to increased nutrient loading 总被引：3，自引：0，他引：3
Marianne Ellegaard Annemarie L. Clarke Nina Reuss Simon Drew Kaarina Weckstrm Stephen Juggins N. John Anderson Daniel J. Conley 《Estuarine, Coastal and Shelf Science》2006,68(3-4):567
This paper presents a study of changes in eutrophication over the past 100 years in a fertile estuary. The Danish estuary Mariager Fjord is a long, narrow sill-fjord with a permanently anoxic basin. In 1997 anoxia spread from the basin to the entire inner estuary, killing almost all eukaryotes and prompting debate on the causes. This paper reports a multi-proxy survey of 210Pb-dated sediment cores from the anoxic basin. Analyses of diatoms, dinoflagellates, pigments and geochemical proxies were used to determine changes in ecosystem structure over the past 100 years. The aim was to establish ‘base-line conditions’, for management purposes, of the biological structure prior to 1900, and to examine possible causes of changes observed. Geochemical proxies total nitrogen (TN), total carbon (TC) and biogenic silica (BSi) were consistently high throughout the sediment record. Increased concentrations of pigments and natural isotopes (δ13C, δ15N) suggested increasing production and nutrient loading. The main changes in the biological proxies occurred between 1915 and the 1940s, and indicated that the estuary has been somewhat eutrophic since 1900, but that the eutrophication process increased over the past 100 years. A reconstruction of TN concentration by a diatom-based transfer function supports this interpretation, with inferred TN ca. 1900 around 60 μmol l−1, and an increase in TN concentration over the past century to ca. 130 μmol l−1 by 1995. Inferred TN decreased to ca. 100 μmol l−1 by 2001, similar to present day monitoring data. 相似文献
3.
Annemarie Meike 《Physics and Chemistry of Minerals》1988,16(2):148-156
The stress gradient calculated from an isotropic elastic approximation does not directly reflect the distribution of permanent deformation in a crystal of the same shape under the same conditions. However, with additional crystallographic constraints, it serves to predict locations where twinning and slip are first activated in a stressed crystal. In this study, thick-walled hollow cylinders were cored from single calcite crystals parallel to 0001 and
. One cylinder of each orientation was loaded at room temperature under one of two conditions: internal pressure (P
p
)=60 MPa, external pressure (P
c
)=100 MPa, or P
p
= 20 MPa, P
c
= 50 MPa. These conditions would produce a radial stress gradient in an isotropic elastic cylinder. Mechanical twins in the deformed calcite samples had a hexagonal distribution in the 0001 oriented cylinder and an orthorhombic distribution in the
oriented cylinder.Zones of dense r-slip dislocations were observed in the
cylinder. Calculated resolved shear stresses for r-slip in either cylinder remained far below the published critical resolved shear stress (c.r.s.s.) value. Calculated contributions from twinning back stress and anisotropy do not account for the difference between the resolved shear stress and the c.r.s.s. These results underscore the necessity of considering dislocation activiation stresses rather than c.r.s.s. in quantitative analyses of heterogeneous of deformation in single crystals. 相似文献
4.
Annemarie Christophersen Nicola Litchfield Kelvin Berryman Richard Thomas Roberto Basili Laura Wallace William Ries Gavin P. Hayes Kathleen M. Haller Toshikazu Yoshioka Richard D. Koehler Dan Clark Monica Wolfson-Schwehr Margaret S. Boettcher Pilar Villamor Nick Horspool Teraphan Ornthammarath Ramon Zuñiga Robert M. Langridge Mark W. Stirling Tatiana Goded Carlos Costa Robert Yeats 《Natural Hazards》2015,79(1):111-135
5.
Annemarie E. Pickersgill Gordon R. Osinski Roberta L. Flemming 《Meteoritics & planetary science》2015,50(9):1546-1561
Shock metamorphism, caused by hypervelocity impact, is a poorly understood process in feldspar due to the complexity of the crystal structure, the relative ease of weathering, and chemical variations, making optical studies of shocked feldspars challenging. Understanding shock metamorphism in feldspars, and plagioclase in particular, is vital for understanding the history of Earth's moon, Mars, and many other planetary bodies. We present here a comprehensive study of shock effects in andesine and labradorite from the Mistastin Lake impact structure, Labrador, Canada. Samples from a range of different settings were studied, from in situ central uplift materials to clasts from various breccias and impact melt rocks. Evidence of shock metamorphism includes undulose extinction, offset twins, kinked twins, alternate twin deformation, and partial to complete transformation to diaplectic plagioclase glass. In some cases, isotropization of alternating twin lamellae was observed. Planar deformation features (PDFs) are notably absent in the plagioclase, even when present in neighboring quartz grains. It is notable that various microlites, twin planes, and compositionally different lamellae could easily be mistaken for PDFs and so care must be taken. A pseudomorphous zeolite phase (levyne‐Ca) was identified as a replacement mineral of diaplectic feldspar glass in some samples, which could, in some instances, also be potentially mistaken for PDFs. We suggest that the lack of PDFs in plagioclase could be due to a combination of structural controls relating to the crystal structure of different feldspars and/or the presence of existing planes of weakness in the form of twin and cleavage planes. 相似文献
6.
Efficient testing of earthquake forecasting models 总被引：1，自引：0，他引：1
David A. Rhoades Danijel Schorlemmer Matthew C. Gerstenberger Annemarie Christophersen J. Douglas Zechar Masajiro Imoto 《Acta Geophysica》2011,59(4):728-747
Computationally efficient alternatives are proposed to the likelihood-based tests employed by the Collaboratory for the Study
of Earthquake Predictability for assessing the performance of earthquake likelihood models in the earthquake forecast testing
centers. For the conditional L-test, which tests the consistency of the earthquake catalogue with a model, an exact test using convolutions of distributions
is available when the number of earthquakes in the test period is small, and the central limit theorem provides an approximate
test when the number of earthquakes is large. Similar methods are available for the R-test, which compares the likelihoods of two competing models. However, the R-test, like the N-test and L-test, is fundamentally a test of consistency of data with a model. We propose an alternative test, based on the classical
paired t-test, to more directly compare the likelihoods of two models. Although approximate and predicated on a normality assumption,
this new T-test is not computer-intensive, is easier to interpret than the R-test, and becomes increasingly dependable as the number of earthquakes increases. 相似文献
7.
Gordon R. Osinski Adam B. Coulter Roberta L. Flemming Alexandra Ozaruk Annemarie E. Pickersgill Alaura C. Singleton 《Meteoritics & planetary science》2023,58(6):775-788
The ~5 km diameter Gow Lake impact structure formed in the Canadian Shield of northern Saskatchewan approximately 197 Myr ago. This structure has not been studied in detail since its discovery during a regional gravity survey in the early 1970s. We report here on field observations from a 2011 expedition that, when combined with subsequent laboratory studies, have revealed a wealth of new information about this poorly studied Canadian impact structure. Initially considered to be a prototypical central peak (i.e., a complex) impact structure, our observations demonstrate that Gow Lake is actually a transitional impact structure, making it one of only two identified on Earth. Despite its age, a well-preserved sequence of crater-fill impactites is preserved on Calder Island in the middle of Gow Lake. From the base upward, this stratigraphy is parautochthonous target rock, lithic impact breccia, clast-rich impact melt rock, red clast-poor impact melt rock, and green clast-poor impact melt rocks. Discontinuous lenses of impact melt-bearing breccia also occur near the top of the red impact melt rocks and in the uppermost green impact melt rocks. The vitric particles in these breccias display irregular and contorted outlines. This, together with their setting within crater-fill melt rocks, is indicative of an origin as flows within the transient cavity and not an airborne mode of origin. Following impact, a hydrothermal system was initiated, which resulted in alteration of the crater-fill impactites. Major alteration phases are nontronite clay, K-feldspar, and quartz. 相似文献
8.
Radiated Energy of Great Earthquakes from Teleseismic Empirical Green’s Function Deconvolution 总被引：1，自引：0，他引：1
Annemarie S. Baltay Gregory C. Beroza Satoshi Ide 《Pure and Applied Geophysics》2014,171(10):2841-2862
We expand on the empirical Green’s function deconvolution method of Ide et al. (2011) to estimate radiated energy for the six largest earthquakes worldwide over the last 10 years: 2011 M w 9.0 Tohoku-Oki, 2004 M w 9.1 Sumatra, 2010 M w 8.8 Maule, 2005 M w 8.7 Nias, 2007 M w 8.5 Bengkulu, and 2012 M w 8.6 off-Sumatra. Deconvolution of P, SV and SH components gives consistent energy results that are comparable to estimates found independently by other researchers. Apparent stress for the five great thrust earthquakes is between 0.4 and 0.8 MPa, while the 2012 off-Sumatra strike-slip earthquake has a higher apparent stress of 3 MPa, which is consistent with other studies that find a tendency for strike-slip events to be more energetic. Our results are within the spread of apparent stress from the wider global earthquake population over a large magnitude range. The azimuthal distribution of energy in each case shows signs of directivity, and in some cases, shows less energy radiated in the trench-ward direction, which may suggest enhanced tsunami potential. We find that eGfs as small as ~M 6.5 can be used for teleseismic deconvolution, and that an eGf-mainshock magnitude difference of 1.5 units yields stable results. This implies that M 8 is the minimum mainshock size for which teleseismic eGf deconvolution will work well. We propose that a database of eGf events could be used to calculate radiated energy and apparent stress of great, hazardous events in near real time, i.e., promptly enough that it could contribute to rapid response measures. 相似文献
9.
Urban social vulnerability assessment with physical proxies and spatial metrics derived from air- and spaceborne imagery and GIS data 总被引：2，自引：0，他引：2
Risk management in urban planning is of increasing importance to mitigate the growing amount of damage and the increasing
number of casualties caused by natural disasters. Risk assessment to support management requires knowledge about present and
future hazards, elements at risk and different types of vulnerability. This article deals with the assessment of social vulnerability
(SV). In the past this has frequently been neglected due to lack of data and assessment difficulties. Existing approaches
for SV assessment, primarily based on community-based methods or on census data, have limited efficiency and transferability.
In this article a new method based on contextual analysis of image and GIS data is presented. An approach based on proxy variables
that were derived from high-resolution optical and laser scanning data was applied, in combination with elevation information
and existing hazard data. Object-oriented image analysis was applied for the definition and estimation of those variables,
focusing on SV indicators with physical characteristics. A reference Social Vulnerability Index (SVI) was created from census
data available for the study area on a neighbourhood level and tested for parts of Tegucigalpa, Honduras. For the evaluation
of the proxy-variables, a stepwise regression model to select the best explanatory variables for changes in the SVI was applied.
Eight out of 47 variables explained almost 60% of the variance, whereby the slope position and the proportion of built-up
area in a neighbourhood were found to be the most valuable proxies. This work shows that contextual segmentation-based analysis
of geospatial data can substantially aid in SV assessment and, when combined with field-based information, leads to optimization
in terms of assessment frequency and cost. 相似文献
10.
Flood risks in a dynamic urban agglomeration: a conceptual and methodological assessment framework 总被引：2，自引：1，他引：1
Annemarie Müller 《Natural Hazards》2013,65(3):1931-1950
The analysis of risk and its causes is a crucial prerequisite for the development of risk prevention and mitigation measures in the scope of disaster risk management. This paper investigates on the problem of annually occurring floods in Santiago de Chile applying a framework for risk assessment, especially developed for the usage in a large urban area. A case-specific set of variables and indicators was compiled to show the relevant components and their interrelations influencing the flood risk and to provide a tool for monitoring and evaluating their changes over time. Methods for gathering information about the three components of risk, that is, hazard, elements at risk, and vulnerability, comprise the interpretation of very high resolution satellite data, the analysis of GIS, and census data as well as household surveys and expert interviews. The work shows how the assessment framework can be applied in practice to derive a geodata-based flood risk map at the scale of the administrative unit of a building block that can be used as a local decision-making tool. 相似文献