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11.
Jennifer M. Galloway Christine T. Doherty R. Timothy Patterson Helen M. Roe 《第四纪科学杂志》2009,24(4):322-335
A pollen‐based study from Tiny Lake in the Seymour‐Belize Inlet Complex of central coastal British Columbia, Canada, permits an evaluation of the dynamic response of coastal temperate rainforests to postglacial climate change. Open Pinus parklands grew at the site during the early Lateglacial when the climate was cool and dry, but more humid conditions in the later phases of the Lateglacial permitted mesophytic conifers to colonise the region. Early Holocene conditions were warmer than present and a successional mosaic of Tsuga heterophylla and Alnus occurred at Tiny Lake. Climate cooling and moistening at 8740 ± 70 14C a BP initiated the development of closed, late successional T. heterophylla–Cupressaceae forests, which achieved modern character after 6860 ± 50 14C a BP, when a temperate and very wet climate became established. The onset of early Holocene climate cooling and moistening at Tiny Lake may have preceded change at more southern locations, including within the Seymour‐Belize Inlet Complex, on a meso‐ to synoptic scale. This would suggest that an early Holocene intensification of the Aleutian Low pressure system was an important influence on forest dynamics in the Seymour‐Belize Inlet Complex and that the study region was located near the southern extent of immediate influence of this semi‐permanent air mass. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
12.
In a previous work (Paouris and Mavromichalaki in Solar Phys. 292, 30, 2017), we presented a total of 266 interplanetary coronal mass ejections (ICMEs) with as much information as possible. We developed a new empirical model for estimating the acceleration of these events in the interplanetary medium from this analysis. In this work, we present a new approach on the effective acceleration model (EAM) for predicting the arrival time of the shock that preceds a CME, using data of a total of 214 ICMEs. For the first time, the projection effects of the linear speed of CMEs are taken into account in this empirical model, which significantly improves the prediction of the arrival time of the shock. In particular, the mean value of the time difference between the observed time of the shock and the predicted time was equal to +3.03 hours with a mean absolute error (MAE) of 18.58 hours and a root mean squared error (RMSE) of 22.47 hours. After the improvement of this model, the mean value of the time difference is decreased to ?0.28 hours with an MAE of 17.65 hours and an RMSE of 21.55 hours. This improved version was applied to a set of three recent Earth-directed CMEs reported in May, June, and July of 2017, and we compare our results with the values predicted by other related models. 相似文献
13.
Prior to the penetration of the European capitalist economy into central and northern Australia, the Aboriginal mode of production was one of hunting and gathering. Spiritual, economic and social relationships betwen people and land produced a spatial distribution of small bands of people living on their traditional lands. To the incoming white settlers the low population density and type of land use appeared uneconomic. This observation was used as ideological justification for the expropriation and development of the land for commercial pastoralism. This paper discusses the articulation of the Aboriginal and European modes of production in the East Kimberley region of northwest Australia. It argues that the introduced capitalist economy virtually destroyed the Aboriginal means of subsistence, incorporating Aborigines into the new mode of production within various subordinate roles. The exploitation of Aborigines, formerly as labour and now predominantely as consumers, is fundamental to the maintenance of the capitalist mode of production in pastoral areas. The spatial effects of the dominant mode of production have been to centralise Aborigines in locations suited to the various phases of development of the European economy, undermining the traditional Aboriginal social-spatial structure. The centralisation of the Aboriginal population also enhances the opportunities for the further development of the mining industry, which is in direct competition with Aboriginal interests in land. Aboriginal resistance to these spatial tendencies is intense in many quarters, but efforts to return to living on traditional lands and to develop alternative ways of living are hampered by the dominant mode of production. 相似文献
14.
Alan Matthews Helen S. Morgans-Bell Hugh C. Jenkyns Ludwik Halicz 《Geochimica et cosmochimica acta》2004,68(14):3107-3123
This study explores the fractionation of iron isotopes (57Fe/54Fe) in an organic-rich mudstone succession, focusing on core and outcrop material sampled from the Upper Jurassic Kimmeridge Clay Formation type locality in south Dorset, UK. The organic-rich environments recorded by the succession provide an excellent setting for an investigation of the mechanisms by which iron isotopes are partitioned among mineral phases during biogeochemical sedimentary processes.Two main types of iron-bearing assemblage are defined in the core material: mudstones with calcite ± pyrite ± siderite mineralogy, and ferroan dolomite (dolostone) bands. A cyclic data distribution is apparent, which reflects variations in isotopic composition from a lower range of δ57Fe values associated with the pyrite/siderite mudstone samples to the generally higher values of the adjacent dolostone samples. Most pyrite/siderite mudstones vary between −0.4 and 0.1‰ while dolostones range between −0.1 and 0.5‰, although in very organic-rich shale samples below 360 m core depth higher δ57Fe values are noted. Pyrite nodules and pyritized ammonites from the type exposure yield δ57Fe values of −0.3 to −0.45‰. A fractionation model consistent with the δ57Fe variations relates the lower δ57Fe pyrite and siderite ± pyrite mudstones values to the production of isotopically depleted Fe(II) during biogenic reduction of the isotopically heavier lithogenic Fe(III) oxides. A consequence of this reductive dissolution is that a 57Fe-enriched iron species must be produced that potentially becomes available for the formation of the higher δ57Fe dolostones. An isotopic profile across a dolostone band reveals distinct zonal variations in δ57Fe, characterized by two peaks, respectively located above and below the central part of the band, and decoupling of the isotopic composition from the iron content. This form of isotopic zoning is shown to be consistent with a one-dimensional model of diffusional-chromatographic Fe-isotope exchange between dolomite and isotopically enriched pore water. An alternative mechanism envisages the infiltration of dissolved ferrous iron from variable (high and low) δ57Fe sources during coprecipitation of Fe(II) ion with dolomite. The study provides clear evidence that iron isotopes are cycled during the formation and diagenesis of organic carbon-rich sediments. 相似文献
15.
Ghislain Dubois Benjamin Sovacool Carlo Aall Maria Nilsson Carine Barbier Alina Herrmann Sébastien Bruyère Camilla Andersson Bore Skold Franck Nadaud Florian Dorner Karen Richardsen Moberg Jean Paul Ceron Helen Fischer Dorothee Amelung Marta Baltruszewicz Jeremy Fischer Françoise Benevise Rainer Sauerborn 《Chemie der Erde / Geochemistry》2013
Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy. 相似文献
16.
17.
EU-US (European Union-United States) interactions in relation to the regulation of genetically modified organisms (GMOs) have been examined in detail in recent years. To do this scholars have tended to focus on a small number of high profile processes, such as the formal complaint of the US to the World Trade Organisation regarding the regulation of GMOs in the Europe. It is important to analyse developments of this kind but overemphasis on them has also lead to a distorted view of the case and a failure to appreciate the significance of other, less visible, types of interaction. In this paper we focus instead on trying to understand the roles played by various EU-US transnational networks—The Transatlantic Business Dialogue, The Transatlantic Economic Partnership, The Transatlantic Consumer Dialogue, The Transatlantic Environmental Dialogue and the EU-US Consultative Forum on Biotechnology. These networks have been trying to shape the regulation of GMOs in both jurisdictions since the mid 1990s. By analysing them through a ‘governance lens’ we find that we can better understand EU-US interactions and the dynamics and influences around the regulation of GMOs. This gives us valuable insights into processes of contemporary governance. 相似文献
18.
Jennifer L. Ruesink Alan C. Trimble Helen Berry Amy G. Sprenger Megan N. Dethier 《Estuaries and Coasts》2014,37(1):149-159
Production and resource use by intertidal taxa were studied in the estuarine fjord of Puget Sound, Washington, USA. Along nearly 100 km, salinity is similar, and intertidal habitat and immersion time were kept consistent, thus allowing a focus on other environmental variables such as temperature and resource availability that could influence growth. Primary producers (ulvoid and fucoid macroalgae) and suspension feeders (oysters and barnacles) were transplanted on three beaches in each of three regions and assessed for individual-level growth, carbon and nitrogen ratios, and stable isotopes. In most transplants, δ13C and C/N showed no regional variation but δ15N was enriched up-estuary. Among environmental variables, chlorophyll a, total suspended solids, and particulate organic matter had small and/or inconsistent regional variation, but temperature was higher up-estuary. For the most intensively studied species (Pacific oyster, Crassostrea gigas) transplanted four times over 2 years, seasonal and regional variation in growth were best predicted by temperature rather than resource availability. Growth rates continued to increase into Totten Inlet, a shallow finger inlet at the head of Puget Sound. As indicators of environmental conditions, the growth and tissue chemistry of intertidal study taxa affirm that sources and amounts of resources show no strong gradients along this estuarine fjord, and they also support temperature as a key factor for performance, with species-specific responses. Higher temperatures may also have community-level impacts, given prior evidence linking beach temperatures to reduced intertidal diversity and biomass into Puget Sound. 相似文献
19.
Helen J. Boon 《Natural Hazards》2014,71(1):683-701
This paper reports exploratory research conducted in a flood-impacted rural Australian town to identify the factors which residents perceived as supporting community resilience to disaster. There is a gap in this research area centred in the Australian disaster context. Since Australia is predicted to be highly impacted by the effects of climate change in the form of an increased incidence of flooding, an urgent need exists to examine the factors that confer resilience to disaster-impacted localities to inform suitable disaster mitigation and adaptation policies for the future. Because of the complexity of community resilience and its interrelationship with individual resilience, a multi-method approach was used: a demographic study to assess community stability and functioning before and after the flood disaster, focus group interviews to obtain from community members their views on what supported them and their community resilience and a survey to generalise the interview findings. Our operating hypothesis was that individuals remaining in the town post-flood were likely to be resilient to the flood disaster. The demographic study results pointed to a resilient community after the floods as they reflected stability in population numbers and socio-economic indicators. The interviews and survey showed that individual resilience was promoted by social connectedness and a sense of place, a factor that was also negatively linked to the desire to relocate from the community. The use of structural equation modelling of our results provided verification of prior research findings about the role of sense of place in supporting individuals’ resilience. Results are discussed in the context of future climate change adaptation policy. 相似文献
20.