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The fisheries sector is currently contending with the hectic development of its own political economy framework being convulsed by the dynamics of decentralisation. This process is enshrouded in an environment of economic globalisation, taking place against the backdrop of the governance approach. With this situation as the starting point, the main goal of this paper is to quantify the effects that the Spanish port devolution process might have on the Spanish fisheries sector through the use of a transfer function model; the volumes of landings at State ports of general interest and their cash value are taken as dependent variables. 相似文献
23.
One of the main concerns of the Common Fisheries Policy (CFP) lies in guaranteeing consistency among the different implemented actions. The main concern is establishing a relationship between the levels of compliance with the Multi-annual Guidance Programme (MAGP), the adoption of total allowable catches (TACs), and the levels of compliance with rules by producers. 相似文献
24.
The roots of the Canadian harp seal hunt can be traced to the 16th Century. But in the mid-20th century, opposition to the commercial hunt became widespread after television images of seal pups being killed with clubs on the pack ice off the coast of Newfoundland were broadcast around the world. International conservation groups, animal welfare groups, animal rights groups, and foreign governments have been calling for the Canadian government to end the commercial seal hunt on the grounds that it is inhumane and that harvest levels are unsustainable. The Canadian government defends the traditional practices of hunting harp seals, argues that seal pelts are an important source of income for sealers, and insists that the killing methods are humane and that harvest levels are sustainable. Emotions run high on both sides of the debate. The purpose of this paper is to evaluate whether or not there is a purely economic argument for ending Canada's commercial seal hunt. The paper finds that the benefits of ending the commercial hunt exceed the costs, but not unequivocally. However, the paper argues there should be a higher criterion—the Pareto criterion—for ending the commercial hunt; that is the hunt should end only if winners compensate the losers. The paper goes on to argue that an effective way to satisfy this criterion is to introduce a system of individual transferable quotas (ITQs) and let the market reveal the value of the commercial seal hunt. In addition to many other advantages such as improving the safety and efficiency of the hunt, the ITQ market could provide a mechanism by which those willing to pay to end the hunt could do so directly to sealers thereby ensuring that the hunt is scaled back or ultimately ended only when it is economically efficient and unambiguously welfare-improving. 相似文献
25.
为了进一步研究唐山地区深部地壳构造与唐山大地震孕育及发生的关系,国家地震局地球物理研究所在石油部物探局的协助下,于1985年1月在唐山震区完成了64km长的深反射剖面野外观测,获得了高分辨率的整个地壳结构的详细资料。分析结果表明,唐山震区内深度500m以上的沉积层十分破碎;结晶基底为前震旦纪地层,埋深2-7km不等,覆盖地层倾斜,且断层发育,其中陡河断裂为正断层,延深至6-7km,推断该断层为1976年唐山发震的重要构造之一。测线上大约21km深处普遍存在一反射层;莫霍面深度在31-32km左右,与该地区折射剖面得到的结果相当一致。 相似文献
26.
27.
We investigate the estimation of interfacial areas, curvatures, and common curve lengths in multiphase porous medium systems. Algorithms are developed to obtain estimates of these quantities based upon a variety of potential data sources and estimation approaches. The accuracy of the derived approximations are evaluated as a function of the data type and resolution of the data. The methods advanced improve upon standard approaches now in use and show excellent accuracy at resolutions on the order of five lattice points per minimum radius of curvature of the object being resolved. Finally, we suggest a promising class of extensions that could lead to further improvements in the accuracy of such methods. 相似文献
28.
铼—锇同位素分析中试样化学预处理方法进展 总被引:4,自引:0,他引:4
评述了用于Re-Os同位素体系分析的化学前处理技术的发展。简要介绍了卡洛斯管熔样法、Os的CCl4提取、溴提取和微蒸馏方法。卡洛斯管封闭熔样方法,有效地防止了Os的挥发损失和保证了Os同位素平衡,是一种很有发展前景的熔样方法。蒸馏法仍是分离和纯化Os的有效方法,溶剂(CCl4)提取和溴提取法在许多实验室里应用,而微蒸馏则是Os的二次纯化的主要方法。Re的化学分离和纯化仍是离子交换和萃取法。引用主要文献29篇。 相似文献
29.
Xiachen Zhi Zicheng Peng Daogong Chen Chunjiang Yu Weidong Sun Laurie Reisberg 《中国科学D辑(英文版)》2001,44(12):1110-1118
The basalt-borne peridotite xenoliths from Jiangsu-Anhui provinces were analyzed for whole rock Os isotopic compositions in
two laboratories of USTC, China and CRPG, France, respectively. The187Os/188Os ratio of the sample set ranges from 0.119 to 0.129 (25 samples, USTC) and from 0.117 to 0.131 (17 samples, CRPG). The Os
isotopic compositions of most samples are less than 0.129 and depleted relatively to the primitive mantle, showing a good
correlation with the major element compositions. With the187Os/188Os-Al2O3 alumichron, the samples yield a model age of 2.5 ± 0.1 Ga (data of USTC) and 1.9 ± 0.1 Ga (data of CRPG), late Archean to
early Pro-terozoic. The two samples with the lowest187Os/188Os ratio (0.119 and 0.117) have the TRD (Re depleted age) of 1.1 Ga (USTC) and 1.4 Ga (CRPG), mid-Proterozoic. The Os isotope model age shows that the peridotite
xenoliths from Cenozoic alkali basalt in Jiangsu-Anhui provinces have an old formation age (early- to mid- Proterozoic). They
are not newly produced mantle after the Phanerozoic replacement of the lithosphere mantle, but residual fractions of Proterozoic
mantle. 相似文献
30.
The ^190Pt-^186Os system should be a unique tracer for mantle processes be-cause both Pt and Os are concentrated in the mantle.The ^190Pt-^186Os system will also be a good supplement to the ^187Re-^187Os system for dating and tracing mantle pro-cesses because the ^190Pt-^186Os system is not so easily contaminated by crustal materials as the ^187Re-^187Os system.In turn,the application of the ^187Re-^187Os system to Pt-enriched materials uncontaminated by crustal materials will indirectly refine the half life of ^190Pt.The ^190Pt is refined.In the coupled ^187Re-^187Os and ^190Pt-^186Os sys-tematics,an ^186Os*/^190Pt-^187Os*/^187Re Concordia diagram similar to the ^206Pb*/^238U-^208Pb*/^232Th Concordia can be constructed.In such a Concordia diagram,a date will be obtained so long as the ^190Pt-^186Os system remains closed even if the ^187Re-^187Os sys -tem is contaminated by crustal materials.In addition ,for the coupled ^190Pt-^186Os and ^187Re-^187Os systematics,the mantle processes and the interactions between the mantle and the crust will be described by two ratios:^186Os/^188Os and ^187Os/^188Os .The coupled ^187Re-^187Os and ^190Pt-^186Os systematics will be a powerful tool in the investigation of the geodynamic history of the Earth because the ^187Re-^187Os system is sensitive to the interactions between the mantle and the crust,while the ^190Pt-^186Os system is a good tracer for mantle processes. 相似文献