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331.
332.
陈宝华 《防灾减灾工程学报》1992,(4)
本文总结了1986年11月15日台湾花莲海域地震及其强余震前电磁辐射的前兆特征。所用的仪器为DDC-2型电子补偿仪、XWX-2042电位差计,记录极距为100m的两埋地电极间所接收到的电磁辐射信息,震前异常波形最大幅度可达187.5mv,为正常背景的十数倍,频谱较宽(0.005—5Hz)。这种特征对认识发生在太平洋板块与亚欧板块上的地震有一定意义。 相似文献
333.
334.
In recent years, churches across the world have become involved in dialogue on the theory and practice of sustainable development. A number of Western churches have expressed their concern about climate change and destructive living patterns, stressing the need for human beings to exercise the care for all creation based on a life of sharing and sacrifice. Some Orthodox churches, however, quite recently included the environmental issues in their agendas. While the Bases of Social Concept, a major doctrine of the Russian Orthodox Church adopted in 2000, for the first time emphasises the Churchs position in overcoming environmental crisis and presents a solid basis on which to build the future environmental strategy of the Church, the Ethiopian Orthodox Church has not yet drawn up a programme document that might serve as a framework for the Churchs current extensive activities in the field of biodiversity conservation and sustainable forestry practices. Hence, despite certain closeness of both institutions, there is the potential for strengthening their roles in promoting sustainable development, based on the Biblical concept that the Earth belongs to the Lord and humans are responsible stewards assigned the duty to work for creation and care for it. This paper seeks to demonstrate by means of comparable analysis between the two Churches, Orthodox in nature but different in rites and religious practices, that traditional, highly conservative faiths may serve as powerful instruments of spreading out the ideas of sustainable development as the basis of spiritual revival in the situation of the two concurrent and interrelated crises – spiritual and ecological.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
335.
Franziska?Pfister Peter?BacciniEmail author 《Environment, Development and Sustainability》2005,7(3):337-361
Food production has to be increased in a sustainable way to meet the future global demand. A key position is attributed to
developing countries. A deepened understanding of their agricultural regions with specific resource endowments and constraints
is therefore crucial. In this study we propose a methodology based on material flux analysis (MFA) to assess the resource
potentials and limitations of a Nicaraguan agricultural region. We focus on current regional and farm resource management
and explore them under two scenarios. Indicators are nitrogen and the degrees of self-sufficiency (DSS) for energy, and the
staples maize and beans. As data is scarce, most information is based on interviews with farmers of four categories and key
persons, and on literature.
The results show that nitrogen management does not differ considerably among categories. Nitrogen is mined mostly from staple
plots. Self-sufficiency for beans is given in an average year. Yet, landless and small farmers neither produce enough maize
for autoconsumption, nor are they self-sufficient for firewood. Energy supply is also the core problem of the region, since
the DSS is 70%. Soil nitrogen
stocks last at most for three more generations. Analyses with the scenario technique show that: (a) Unlimited population growth
has serious consequences in the near future e.g. severe shortage of energy and food. (b) Alternative farming systems are possible,
but they require reducing the population by a factor 2, and thus the creation of jobs in a Hinterland.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
336.
S.?G.?WilsonEmail author M.?E.?Lutcavage R.?W.?Brill M.?P.?Genovese A.?B.?Cooper A.?W.?Everly 《Marine Biology》2005,146(2):409-423
Pop-up satellite archival tags were implanted into 68 Atlantic bluefin tuna (Thunnus thynnus Linnaeus), ranging in size from 91 to 295 kg, in the southern Gulf of Maine (n=67) and off the coast of North Carolina (n=1) between July 2002 and January 2003. Individuals tagged in the Gulf of Maine left that area in late fall and overwintered in northern shelf waters, off the coasts of Virginia and North Carolina, or in offshore waters of the northwestern Atlantic Ocean. In spring, the fish moved either northwards towards the Gulf of Maine or offshore. None of the fish crossed the 45°W management line (separating eastern and western management units) and none traveled towards the Gulf of Mexico or the Straits of Florida (known western Atlantic spawning grounds). The greatest depth recorded was 672 m and the fish experienced temperatures ranging from 3.4 to 28.7°C. Swimming depth was significantly correlated with location, season, size class, time of day, and moon phase. There was also evidence of synchronous vertical behavior and changes in depth distribution in relation to oceanographic features.Communicated by J.P. Grassle, New Brunswick 相似文献
337.
Sébastien?JaquemetEmail author Matthieu?Le Corre Francis?Marsac Michel?Potier Henri?Weimerskirch 《Marine Biology》2005,147(3):573-582
We investigated the foraging habitats of the winter breeding community of tropical seabirds from Europa Island (Mozambique Channel) in September 2003. We focused our study on the dominant species of this austral community, the sooty tern (Sterna fuscata), the red-footed booby (Sula sula), and the frigatebirds, including the great (Fregata minor) and the lesser frigatebirds (F. ariel). We considered the at-sea distribution and abundance of these species in relation to chlorophyll concentration, sea-surface temperatures, sea-surface height anomalies, depth of the thermocline, distance to the colony, and presence of surface marine predators, flying fishes and other seabirds. Although the marine environment where seabirds foraged was oligotrophic, it presents the best feeding opportunities for seabirds for the area in winter. Our study demonstrates that the winter-breeding seabird species of Europa Island tend to forage in productive waters in association with other marine predators when possible. Sooty terns and frigatebirds were widely distributed in the whole study area, whereas red-footed boobies were not found farther than 160 km from their colonies and were associated with relatively productive waters. Sooty terns and red-footed boobies were aggregated where flying fishes were abundant. The presence of other marine predators was associated with larger multispecies feeding flocks than when no association occurred. Sooty terns, which are numerically dominant at Europa and adopted network foraging, seem to be catalysts of feeding events, and represented a good target for the other foraging species, especially frigatebirds. However, when possible, frigatebirds favour association with flocks of red-footed boobies.Communicated by S.A. Poulet, Roscoff 相似文献
338.
The feeding activity rhythm of Palaemonetes varians (Leach 1814) was studied by collecting stomachs over a 24-h cycle in four different seasons of 1996 and spring–summer of 1997 to assess a regulation of this behaviur dependent upon seasonal variations in photoperiod length. A total of 6,692 stomachs were collected from a population reared in an extensive earthen pond located in the Guadalquivir Estuary salt marshes (Spain). Stomach fullness (f) classification was performed with a stereomicroscope by means of a four-point visual qualitative scale. Results showed that a high proportion of stomachs were empty in all seasons considered and a great variability in the data occurred irrespective of the time of the day. The number of full stomachs at each catch were represented over 24-h for each sampling season. Time series showed the occurrence of a feeding activity rhythm phased at day–night transitions. The sunset peak occurred in all months of sampling, while the sunrise one occurred in summer. Results are discussed in relation to available data on behavior, moulting, and reproduction of this and other species of the same genus. 相似文献
339.
The morphological expressions of imposex in gastropods have been classified into seven stages (S0–S6) with three types (a, b and c). This typical imposex scheme, however, fails to cover some new findings such as specimens with the proximal vas deferens section passing by the vaginal opening (VDSP) and aborted egg capsules. In the present study, Cantharus cecillei was sampled from the coastal waters of China from May to November in 2003. This species showed all the morphological expressions in the typical imposex scheme with the exception of S1b and S2b. In addition, specimens with VDSP occurred in all stages other than stage 4, and were documented for the first time with scanning electron micrographs or in histological sections. Besides VDSP, which was observed exteriorly, excrescent tissue, e.g. the vas deferens, also originated in the ventral channel or the inner wall of the pallial oviduct was extruded. Based on these new findings, the typical imposex scheme was modified to obtain one valid for C. cecillei. Types a*, b* and c* were added as new types corresponding to types a, b and c, respectively. S4* was also rearranged to correspond to S4; S4*, thus, no longer represented the end of imposex development. The updated scheme was not only valid for describing diverse expressions of imposex development in C. cecillei and Nassarius reticulatus, but could also be generalized to define various forms of VDSP in other species. Histological observation indicated that egg capsules would be blocked by the tissues of the vas deferens section or the extrusion of the pallial oviduct wall. This new mechanism, leading to the sterilization of imposex-affected females, was first conclusively revealed and described in the present scheme.Communicated by T. Ikeda, Hakodate 相似文献
340.
Judith-Anne?MarshallEmail author Tom?Ross Stephen?Pyecroft Gustaaf?Hallegraeff 《Marine Biology》2005,147(2):541-549
This study investigated the possible roles of superoxide produced by raphidophyte and prymnesiophyte microalgae as an ichthyotoxic agent to damselfish and an allelopathic agent to bacteria. We found that the rate of superoxide production varied with algal cell density, with cell densities of the raphidophyte Chattonella marina >10,000 cells ml–1 producing less environmental levels of superoxide per cell (94±14 chemiluminescence units) than cell densities <10,000 cells=">10,000>–1 (390±54 units per cell). Microalgal cells have the capacity to change their superoxide production rate over a period of 1 h, dependent on cell density and metabolic activity. We also examined the effect of superoxide on suppression of bioluminescence of the marine bacterium Vibrio fischeri as a model for bacterial alleopathy and found that both superoxide and free fatty acids such as eicosapentaenoic acid (EPA; 20:53) present in raphidophyte microalgal cells cause suppression of bacterial bioluminescence. The combination of superoxide in the presence of EPA further enhanced bioluminescence suppression. Superoxide was also found to enhance the toxicity of free fatty acid EPA to damselfish (Acanthochromis polycanthus) at concentrations as low as 0.2 mg l–1. In conclusion, consideration should be given to density dependent and/or metabolic variations of toxicity when publishing minimum alert levels for superoxide producing ichthyotoxic microalgal species. A secondary role of superoxide production may be to enhance the toxicity of algal exudates or serve as an allelopathic agent against bacterial fouling. 相似文献