We examine the implications of climate change for fishery governance using seven international fishery case studies in low, mid and high latitudes, including eastern Australia, the western Pacific Ocean, Alaska, west coast United States, Hawaii, west coast Canada and France. Climate change adds uncertainty about fish stock productivity, migratory patterns, trophic interactions and vulnerability of fish populations to fishing pressure. 相似文献
Stimulus to reach the millennium goals of poverty abatement and empowerment, including education and employment, for the large part of the population in the coastal zone can be found in the resources and services of oceans and coasts; the required financial means, given political will and right priorities, can be provided through implementation of the related international conventions, in particular UNCLOS with the EEZ, the Common Heritage of Mankind and other provisions, Agenda 21 [1] of UNCED and the WSSD 2002 Ocean Targets; the motivation is the necessity to address over-exploitation, depletion and destruction of resources, habitats and coastal ecosystem services, global changes, as well as economic transformations and social conditions of poverty, employment and unequity. Achieving adequate management and protection of natural assets as ecosystems and their services, habitats, biodiversity requires that the socio-economic and human security needs of the coastal populations are met. One way to reach the goal is to enable them, representing about 50% of the global population and increasing, to fight poverty and cope with uncertainties and changing conditions of employment, environment and sustainability through proper governance of the coastal and ocean assets. This includes provision of education and knowledge as regards these assets and their proper uses. They include energy, water, food, transportation and trade, communication, coastal developments, tourism, recreation and ecosystem services, as well as the need to properly manage them.The present economic system cannot fully harmonize with the required governance, partly since the ecosystem resources and services are not internalised in the market-oriented system. This calls for a revised education and training system, more comprehensive than the present, taking into account the social, cultural and environmental requirements, and stressing the sustainable development paradigm. In order to achieve ocean governance and comprehensive human security an understanding of the system is needed. This is substantiated through the Decade of Education for Sustainable Development as well as the Millennium Ecosystem Assessment.The aim here is to discuss some of the issues in context of implementation of related ocean conventions and commitments, which include achieving ocean governance, and to elucidate opportunities given by oceans and coasts, also in generating employment and providing for basic human needs. 相似文献
We use an axisymmetric, spherical Earth finite difference algorithm to model SH -wave propagation through cross-sections of laterally varying lower mantle models beneath the Cocos Plate derived from recent data analyses. Synthetic seismograms with dominant periods as short as 4 s are computed for several models: (1) a D" reflector 264 km above the core–mantle boundary with laterally varying S -wave velocity increases of 0.9–2.6 per cent, based on localized structures from a 1-D double-array stacking method; (2) an undulating D" reflector with large topography and uniform velocity increase obtained using a 3-D migration method and (3) cross-sections through the 3-D mantle S -wave velocity tomography model TXBW. We apply double-array stacking to assess model predictions of data. Of the models explored, the S -wave tomography model TXBW displays the best overall agreement with data. The undulating reflector produces a double Scd arrival that may be useful in future studies for distinguishing between D" volumetric heterogeneity and D" discontinuity topography. Synthetics for the laterally varying models show waveform variability not observed in 1-D model predictions. It is challenging to predict 3-D structure based on localized 1-D models when lateral structural variations are on the order of a few wavelengths of the energy used, particularly for the grazing geometry of our data. Iterative approaches of computing synthetic seismograms and adjusting model characteristics by considering path integral effects are necessary to accurately model fine-scale D" structure. 相似文献
The authors have investigated the biochemical events by which marine algal virus infection induces cell cycle arrest. The key G2/M-phase regulatory proteins are analyzed by immunobloting in unicellular Emiliania huxleyi, suggesting that virus induced cell cycle arrest is related with virus''s effect on cyclins and cyclin dependent kinases. E. huxleyi virus (EhV) represses Cdc2/cyclinB complex activity by inhibiting the activity of Cdc2 kinase in a phosphorylation-related manner, blocking host cells G2/M checkpoint. Dephosphorylated/inactive Cdc25C combined with up-regulation of Wee1 expression at early infect period appears to be important mechanisms by which EhV represses Cdc2/cyclinB complex activity that is required for entry into M phase. This study has allowed us to confirm that algal virus infection leads to selective activation or inhibition of certain cell-cycle factors, which may play a significant role in establishing a more efficient environment for viral gene expression and DNA replication. 相似文献
Magnetic flux tubes reaching from the solar convectivezone into the chromosphere have to pass through the relatively cool, and therefore non-ideal (i.e. resistive) photospheric region enclosed between the highly ideal sub-photospheric and chromospheric plasma. It is shown that stationary MHD equilibria of magnetic flux tubes which pass through this region require an inflow of photospheric material into the flux tube and a deviation from iso-rotation along the tube axis. This means that there is a difference in angular velocity of the plasma flow inside the tube below and above the non-ideal region. Both effects increase with decreasing cross section of the tube. Although for characteristic parameters of thick flux tubes the effect is negligible, a scaling law indicates its importance for small-scale structures. The relevance of this `inflow effect' for the expansion of flux tubes above the photosphere is discussed. 相似文献
In connection with the building of a railway tunnel through the City of Oslo, temporary improvement of the soft clay by freezing was considered in order to reinforce the tunnel ceiling in an area where the rock cover was insufficient. The same solution was also considered for another part of the tunnel where the problem was to prevent bottom heave failure in a deep excavation.
As this marine clay deposit has a very high salt content (about 25 g/l pore liquid), it was reasonable to believe that the strength of the frozen clay would be relatively low compared to previously published data concerning fresh clay soils. To investigate the stress—strain properties of frozen Oslo clay, a fairly comprehensive research programme was carried out; including two different temperature levels and using different testing techniques. The clay was tested in compression, tension, bending and shear, respectively. The tests were run very slowly, time to failure was normally 70–100 days.
This paper presents the main test results, which indicate that there exists a fairly well defined critical shear stress level for a given freezing temperature. As long as the stresses do not exceed this stress level, the creep deformations are small and the creep rates are constant or decreasing with time. On the other hand, higher shear stresses lead to very extensive deformations or failure. 相似文献
The Loop meteorite was found in 1962 in Gaines County, Texas, at a location very close to that where the Ashmore chondrite was found in 1969. The two specimens were assumed to be fragments of the same meteorite. The Loop meteorite is a type L6 chondrite composed of olivine (Fo75.4Fa24.6), orthopyroxene (En77.6Wo1.5Fs20.9), clinopyroxene (En47.5Wo45.1Fs7.4), plagioclase (Ab84.3Or5.5An10.2), Fe-Ni metal, troilite, and chromite. Fe-Ni metal is represented by kamacite (5.8-6.4 wt % Ni, 0.88-1.00 wt % Co), taenite (30.0–52.9 wt % Ni, 0.16-0.34 wt % Co), and plessite (16.8–28.5 wt % Ni, 0.38-0.54 wt % Co). Native copper occurs as rare inclusions in Fe-Ni metal. Both chondrules and matrix have similar mineral compositions. The mineral chemistry of the Loop meteorite is quite different from that of the Ashmore, which was classified as an H5 chondrite by Bryan and Kullerud (1975). Therefore, the Ashmore and Loop meteorites are two different chondrites, even though they were recovered from the same geographic location. 相似文献
The subject of commodity cartels has gained the attention of a concerned world since the success of OPEC. The matter is of special importance to both economic and political geographers because of the new spatial patterns that such international groupings appear likely to create. In an effort to satisfy the need for a method of identifying commodities susceptible to cartelization, this paper proposes a graph theoretic model. To illustrate its use, the model is applied here to twelve minerals. The results indicate that the model would have anticipated the success of two existing cartels, the possibilities for a third, and the difficulties attending efforts to create still another. 相似文献