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81.
Kirt E. Moody 《Estuaries and Coasts》2003,26(3):759-764
Blue crabsCallinectes sapidus in lower Chesapeake Bay are subject to high rates of predation during the late summer of their first year of growth as they
migrate out of vegetated nursery habitats. Predators, potentially contributing to this pattern, were identified in video-recorded
field observations of tethered juvenile crabs (20–25 mm carapace width). Predators were also tested in large laboratory tanks
containing similarly-sized untethered crabs as prey. Seven different predators attacked tethered crabs in the field. Only
two predators, larger blue crabs and northern puffers,Sphoeroides maculatus, consistently succeeded in preying on crabs in both field and laboratory settings. These results confirm the importance of
cannibalism on juvenile blue crabs and identify puffers as a potentially overlooked source of predation pressure. 相似文献
82.
Bernard Henry Grobéty 《Contributions to Mineralogy and Petrology》1997,127(3):237-247
Anthophyllite crystals found in ultramafic lenses of the Lepontine Alps (Switzerland) contain coherent, submicroscopic intergrowths
of ordered and disordered biopyribole polysomes. The chain width distributions of disordered polysomes were analyzed using
high resolution transmission electron microscopy (HRTEM). Chains wider than triple were interpreted as intermediate products
in the transformation of anthophyllite to the triple chain silicate jimthompsonite. The concentration of individual chain
types is strongly correlated with the reaction progress. Based on observed zipper terminations and the transformation rules
given by Veblen and Buseck (1980) a scheme of possible reaction paths leading from anthophyllite to jimthomp sonite is proposed.
The reaction scheme and a simple kinetic model for elementary reactions allow modeling of the observed chain width distributions.
The model suggests that the complex reaction paths involving steps with increasing and decreasing chain width are more important
in the formation of jimthompsonite than the direct transformation from anthophyllite. The wide chains (>triple) occurring
as intermediate products of the multi-step paths are structurally closer to talc than jimthompsonite. The back-transformation
of these wide chains to triple chains is, therefore, a strong argument that jimthompsonite is a stable phase and not only
a metastable intermediate product in the transformation of anthophyllite to talc.
Received: 8 July 1996 / Accepted: 13 December 1996 相似文献
83.
84.
In the first Kyoto commitment period Russia could be the major supplier for the greenhouse gases (GHG) emissions market. Potential Russian supply depends on the ability of Russia to keep GHG emissions lower than the Kyoto target. In the literature there is no common understanding of the total trading potential of Russia at the international carbon market. In this paper we focus on CO2 emission, which constituted nearly 80%of Russian GHG emission. We compare different projections of Russian CO2emission and analyze the most important factors, which predetermine the CO2emission growth. In a transition economy these factors are: Gross Domestic Product(GDP) dynamic, changes of GDP structure, innovation activity, transformation of export-import flows and response to the market signals. The input-output macroeconomic model with the two different input-output tables representing old and new production technologies has been applied for the analysis to simulate technological innovations and structural changes in the Russian economy during transition period. The Russian supply at the international GHG market without forest sector may be up to 3 billion metric ton of CO2 equivalent. Earlier actions to reduce CO2 emission are critical to insure theRussiansupply at the international carbon market. With regard to the current status of the Russian capital market, the forward trading with OECD countries is only the possibility to raise initial investments to roll no-regret and low-cost GHG reduction. This paper discusses uncertainties of RussianCO2emission dynamics and analyzes the different incentives to lower the emission pathway. 相似文献
85.
Yijun Zhagn Wansheng Dong Yang Zhao Guangshu Zhang Hongfa Zhang Chengpin Chen Tong Zhang 《中国科学D辑(英文版)》2004,47(1):108-114
The comprehensive observations on lightning discharges were conducted in Naqu area of Qinghai-Tibet Plateau in summer of 2002. The electric structures of thunderstorms and the characteristics of lightning discharges at initial stage were analyzed by using the observation data. The results show that most of intracloud (IC) lightning flashes were polarities inverted in thunderstorms with tripole electric charge structure and occurred between negative charge region located in the middle of the thunderstorm and positive charge region located at the bottom of the thunderstorm. The radiation characteristics of discharge processes in cloud with longer lasting time involved in Cloud-to-Ground (CG) lightning flashes were similar to that of IC discharges. A lot of radiation pulses were produced in these discharge processes. Because the IC discharges took place at the bottom of thundercloud and were near the ground, they may produce more serious damage to equipment on the ground therefore should not be neglected in lightning protection. 相似文献
86.
87.
Ninad R. Bondre Raymond A. Duraiswami Gauri Dole 《Journal of Earth System Science》2004,113(4):809-817
The nature and style of emplacement of Continental Flood Basalt (CFB) lava flows has been a matter of great interest as well
as considerable controversy in the recent past. However, even a cursory review of published literature reveals that the Columbia
River Basalt Group (CRBG) and Hawaiian volcanoes provide most of the data relevant to this topic. It is interesting to note,
however, that the CRBG lava flows and their palaeotopographic control is atypical of other CFB provinces in the world. In
this paper, we first present a short overview of important studies pertaining to the emplacement of flood basalt flows. We
then briefly review the morphology of lava flows from the Deccan Volcanic Province (DVP) and the Columbia-Oregon Plateau flood
basalts. The review underscores the existence of significant variations in lava flow morphology between different provinces,
and even within the same province. It is quite likely that there were more than one way of emplacing the voluminous and extensive
CFB lava flows. We argue that the establishment of general models of emplacement must be based on a comprehensive documentation
of lava flow morphology from all CFB provinces. 相似文献
88.
Helen Ruth Aspaas 《GeoJournal》2004,61(3):281-289
Women in many rural areas of the US often engage in small-scale businesses as one of several avenues for contributing to household
incomes. In those geographical areas that contain a significant minority population, many of the women's businesses display
the cultural diversity of the regions in which they live. Likewise, women's roles as economic providers as well as wives and
mothers are reflected in the manner in which they operate their businesses. Candida Brush suggests that women's strategies
for operating their businesses are highly integrative because women's business decisions are intertwined with familial responsibilities,
household economic demands and desires to contribute to their communities. Hispanic and Native American women in the Four
Corners region of southwestern US and African American women in central Virginia participated in interviews in which they
responded to numerous short answer and open-ended questions about their businesses and decision-making strategies. From these
interviews an image emerges of rural minority business women who are operating their businesses at the nexus of family obligations,
economic necessities, cultural ties and with a commitment for serving their communities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
89.
The COUPLEX1 Test case (Bourgeat et al., 2003) is devoted to the comparison of numerical schemes on a convection–diffusion–reaction problem. We first show that the results of the simulation can be mainly predicted by a simple analysis of the data. A finite volume scheme, with three different treatments of the convective term, is then shown to deliver accurate and stable results under a low computational cost. 相似文献
90.
In the Aspe Valley (western Pyrenees), the Europe/Iberia boundary corresponds to a complex fracturing zone, called the ‘Bielle–Accous Wrench-Faulting Corridor’, which represents the classical ‘North-Pyrenean Fault’. Located between the High Primary Range and the North-Pyrenean Zone, the BAWC shows different south-verging sheets mainly composed of Triassic materials. The Bedous ophite, associated with Muschelkalk and Keuper sediments, is also Triassic in age and involved in the same Pyrenean thrusting structures. So, contrary to a recent interpretation, this magmatic rock cannot be related to a supposed Danian plutonism inducing metamorphic processes in the surrounding Mesozoic formations. To cite this article: J. Canérot et al., C. R. Geoscience 336 (2004). 相似文献