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501.
This paper presents an evaluation of the role of marine citizenship in improving marine environmental health and marine governance. Marine citizenship describes the rights and responsibilities of an individual towards the marine environment, which support the achievement of marine policy objectives at the national level. It is argued that marine citizenship requires an enhanced awareness of marine environmental issues, an understanding of the role of personal behaviour in creating and resolving marine environmental issues, and a shift in values to promote marine pro-environmental behavioural choices. It is concluded that the value shift is likely to be produced by the development of an altered relationship between the state and the individual, in which the expectations placed on citizens by the state are extended to include marine pro-environmental behaviour. The paper is intended to stimulate debate and the authors invite and encourage replies to the ideas contained within the paper. 相似文献
502.
Karyn Morrissey Graham Clarke Dimitris Ballas Stephen Hynes Cathal O'Donoghue 《Area》2008,40(3):354-364
This paper analyses the effect accessibility has on General Practitioner (GP) utilisation rates at the sub-national level for Ireland. Specifically, the aim of this paper is to estimate whether there is an urban–rural differential in GP utilisation rates. We do this by simulating micro-level healthcare data. Using this synthetic data, simple logit models are employed to estimate the likelihood that individuals in different jurisdictions will attend a GP surgery. These individual logit estimates are then inputted into a spatial interaction model to highlight areas with low GP accessibility given their health status. The policy implications of these results are discussed in relation to both the healthcare literature and current Irish healthcare policy. 相似文献
503.
Agnieszka?M.?PiechockaEmail authorView authors OrcID profile Courtney?J.?Gregory Jian-Wei?Zi Stephen?Sheppard Michael?T.?D.?Wingate Birger?Rasmussen 《Contributions to Mineralogy and Petrology》2017,172(8):63
Although zircon is the most widely used geochronometer to determine the crystallisation ages of granites, it can be unreliable for low-temperature melts because they may not crystallise new zircon. For leucocratic granites U–Pb zircon dates, therefore, may reflect the ages of the source rocks rather than the igneous crystallisation age. In the Proterozoic Capricorn Orogen of Western Australia, leucocratic granites are associated with several pulses of intracontinental magmatism spanning ~800 million years. In several instances, SHRIMP U–Pb zircon dating of these leucocratic granites either yielded ages that were inconclusive (e.g., multiple concordant ages) or incompatible with other geochronological data. To overcome this we used SHRIMP U–Th–Pb monazite geochronology to obtain igneous crystallisation ages that are consistent with the geological and geochronological framework of the orogen. The U–Th–Pb monazite geochronology has resolved the time interval over which two granitic supersuites were emplaced; a Paleoproterozoic supersuite thought to span ~80 million years was emplaced in less than half that time (1688–1659 Ma) and a small Meso- to Neoproterozoic supersuite considered to have been intruded over ~70 million years was instead assembled over ~130 million years and outlasted associated regional metamorphism by ~100 million years. Both findings have consequences for the duration of associated orogenic events and any estimates for magma generation rates. The monazite geochronology has contributed to a more reliable tectonic history for a complex, long-lived orogen. Our results emphasise the benefit of monazite as a geochronometer for leucocratic granites derived by low-temperature crustal melting and are relevant to other orogens worldwide. 相似文献
504.
505.
Stephen Jay 《Marine pollution bulletin》2010,60(4):493-499
The development of offshore wind energy has started to take place surprisingly quickly, especially in North European waters. This has taken the wind energy industry out of the territory of planning systems that usually govern the siting of wind farms on land, and into the world of departmental, sectoral regulation of marine activities. Although this has favoured the expansion of offshore wind energy in some respects, evidence suggests that the practice and principles of spatial planning can make an important contribution to the proper consideration of proposals for offshore wind arrays. This is especially so when a strategic planning process is put in place for marine areas, in which offshore wind is treated as part of the overall configuration of marine interests, so that adjustments can be made in the interests of wind energy. The current process of marine planning in the Netherlands is described as an illustration of this. 相似文献
506.
507.
We present multi-parameter geophysical measurements of rainfall-induced lahars at Semeru Volcano, East Java, using two observation
sites 510 m apart, 11.5 km from the summit. Our study site in the Curah Lengkong channel is composed of a 30-m wide box-valley,
with a base of gravel and lava bedrock, representing an ideal geometry for high density measurements of active lahars. Instrumentation
included pore-pressure sensors (stage), a broad-band seismograph (arrival times, vibrational energy, and turbulence), video
footage, and direct bucket sampling. A total of 8 rainfall-induced lahars were recorded, with durations of 1–3 h, heights
0.5–2 m, and peak velocities 3–6 m/s. Flow types ranged from dilute to dense hyperconcentrated flows. These recorded flows
were commonly composed of partly coalesced, discrete and unsteady gravity current packets, represented by multiple peaks within
each lahar. These packets most likely originate from multiple lahar sources, and can be traced between instrument sites. Those
with the highest concentrations and greatest wetted areas were often located mid-lahar at our measured reach, accelerating
towards the flow front. As these lahars travel downstream, the individual packets thus coalesce and the flow develops a more
organised structure. Observations of different degrees of coalescence between these discrete flow packets illustrate that
a single mature debris flow may have formed from multiple dynamically independent lahars, each with different origins. 相似文献
508.
Tiffany A. Wilson Aria Amirbahman Stephen A. Norton Mary A. Voytek 《Journal of Paleolimnology》2010,44(1):279-294
Historical phosphorus (P) dynamics were studied using sediment cores from three oligotrophic, acidic lakes in Maine, USA.
Long-term oligotrophy of these lakes is consistent with high sediment aluminum (as Al(OH)3) concentrations, as Al inhibits internal P loading, even under reducing conditions. The role of microbially-mediated reactions
in controlling redox conditions was evaluated by estimating microbial biomass and relative abundance of specific functional
groups. Sediments were fractionated using a sequential chemical extraction technique and all lakes met criteria for P retention
based on threshold sediment concentrations of Al, Fe, and P fractions as determined by (Kopáček et al. (2005) Limnol Oceanogr 52: 1147–1155). Sediment NaOH-extractable molybdate-reactive P (rP) and non-reactive P (nrP) represent P
associated with non-reducible phases, and organic matter-related P, respectively. Total P (TP) does not decrease with sediment
depth, as is typical of eutrophic lake sediments; however, nrP/TP decreases and rP/TP increases for all three lakes, indicating
nrP mineralization without any significant upward diffusion and release into the hypolimnion; i.e. diagenesis of P is conservative
within the sediment. Two diagenetic models were developed based on nrP and rP concentrations as a function of sediment age.
The first model assumes a first-order decay of nrP, the rate coefficient being a function of time, and represents irreversible
nrP mineralization, where the produced PO4 is permanently sequestered by the sediment. The second model assumes a first-order reversible transformation between nrP
and rP, representing biotic mineralization of organic P followed by incorporation of inorganic P into microbial biomass. Both
models reflect preservation of TP with no loss to overlying water. The rate coefficients give us insight into qualities of
the sediment that have affected mineralization and sequestration of phosphorus throughout the 210Pb-dateable history of each lake. Similar models could be constructed for other lakes to help reconstruct their trophic histories.
Paleolimnological reconstruction of the sediment P record in oligotrophic lakes shows mineralization of nrP to rP, but unlike
the case in eutrophic lake sediments, sediment TP is preserved in these sediments. 相似文献
509.
María Luisa Ávila-Jiménez Stephen J. Coulson Torstein Solhøy & Anna Sjöblom 《Polar research》2010,29(1):127-137
There are over 500 species of arthropods recorded from Svalbard. These animals overwinter either within the soil or on the ground surface, and have to tolerate an environment where the ground is frozen for over 9 months each year. Three cold-tolerance strategies have been described from Svalbard invertebrates: freeze avoidance, freeze tolerance and desiccation. Once in a cold-tolerant state the animals can be extremely cold tolerant in terms of both minimum exposure temperature and period of exposure. How the overwintering capabilities of these animals will be affected by climate changes during the next 100 years, as predicted by climate models, is not yet known. Four principle factors with an impact on overwintering of the terrestrial arthropod fauna are outlined here: (1) warmer winter temperatures, with an increased frequency of extreme events such as freeze–thaw cycles and surface icing; (2) changes in snow fall and snow lie; (3) pollutant load; and (4) dispersal of invertebrates to Svalbard. Finally, areas where further research is required are highlighted: including the development of controlled multi-season field experiments; effect of freeze–thaw cycles; changes in thickness and distribution of snow lie, with the subsequent effects on duration of the summer period; chill susceptibility of soil arthropods; assessing potential colonizing species and the likelihood of these species becoming established; assessing the effect of gene flow from surrounding populations; interactions between pollution and cold tolerance; anoxia stress; and the genetics of cold tolerance. 相似文献
510.
The spatial and temporal distribution of snow cover extent (SCE) and snow water equivalent (SWE) play vital roles in the hydrology of northern watersheds. We apply remotely sensed Special Sensor Microwave Imager (SSM/I) data from 1988 to 2007 to explore the relationships between snow distribution and the hydroclimatology of the Mackenzie River Basin (MRB) of Canada and its major sub-basins. The Environment Canada (EC) algorithm is adopted to retrieve the SWE from SSM/I data. Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day maximum snow cover extent products (MOD10A2) are used to estimate the different thresholds of retrieved SWE from SSM/I to classify the land cover as snow or no snow for various sub-basins in the MRB. The sub-basins have varying topography and hence different thresholds that range from 10 mm to 30 mm SWE. The accuracy of snow cover mapping based on the combination of several thresholds for the different sub-basins reaches ≈ 90%. The northern basins are found to have stronger linear relationships between the date on which snow cover fraction (SCF) reaches 50% or when SWE reaches 50% and mean air temperatures, than the southern basins. Correlation coefficients between SCF, SWE, and hydroclimatological variables show the new SCF products from SSM/I perform better than SWE from SSM/I to analyze the relationships with the regional hydroclimatology. Statistical models relating SCF and SWE to runoff indicate that the SCF and SWE from EC algorithms are able to predict the discharge in the early snow ablation seasons in northern watersheds. 相似文献