A common garden experiment with larval Northeast Arctic and Norwegian coastal cod cohorts in replicated mesocosms

A replicated mesocosm experiment was carried out to evaluate differential effects of feeding conditions for larval Northeast Arctic (NA) cod and Norwegian coastal (NC) cod. The two populations were (1) reared together with a 6-day older NA cohort (mixed) in high (HC) and low prey concentration (LC; 2000 and 200 prey/L initially), and (2) reared separately in HC treatments (non-mixed) to be able to evaluate both the effect of feeding conditions and possible effects of size interaction within mesocosms. The larvae were fed natural zooplankton, and the two stocks were identified in the mixed mesocosms by otolith marking. NA larvae hatched at a larger size, had higher growth rates, and survived better than NC larvae in both mixed and non-mixed mesocosms in the HC treatment. The second cohort clearly survived better in the non-mixed than in the mixed mesocosms, indicating the presence of an interaction effect before cannibalism could occur. We found a significant higher weight-at-length between NC and NA larvae (<12 mm), which was bigger than the effect difference due to feeding conditions. Furthermore, a positive relation between survival and initial growth within mesocosms was found. We suggest that lower growth at early larval stages was accompanied by lower survival, and suggest that this was further enhanced when larvae interacted with older and larger larvae.     

An introduction to ultrahigh-pressure metamorphism

Abstract Ultrahigh-pressure (UHP) metamorphism refers to mineralogical and structural readjustment of supracrustal protoliths and associated mafic-ultramafic rocks at mantle pressures greater than ∼ 25 kbar (80-90 km). Typical products include metapelite, quartzite, marble, granulite, eclogite, paragneiss and orthogneiss; minor mafic and ultramafic rocks occur as eclogitic-ultramafic layers or blocks of various dimensions within the supracrustal rocks. For appropriate bulk compositions, metamorphism at great depths produces coesite, microdiamond and other characteristic UHP minerals with unusual compositions. Thus far, at least seven coesite-bearing eclogitic terranes and three diamond-bearing UHP regions have been documented. All lie within major continental collision belts in Eurasia, have similar supracrustal protoliths and metamorphic assemblages, occur in long, discontinuous belts that may extend several hundred kilometers or more, and typically are associated with contemporaneous high-P blueschist belts. This paper defines the P-T regimes of UHP metamorphism and describes mineralogical, petrological and tectonic characteristics for a few representative UHP terranes including the western gneiss region of Norway, the Dora Maira massif of the western Alps, the Dabie Mountains and the Su-Lu region of east-central China, and the Kokchetav massif of the former USSR. Prograde P-T paths for coesite-bearing eclogites require abnormally low geothermal gradients (approximately 7°C/km) that can be accomplished only by subduction of cold, oceanic crust-capped lithosphere ± pelagic sediments or an old, cold continent. The preservation of coesite inclusions in garnet, zircon, omphacite, kyanite and epidote, and microdiamond inclusions in garnet and zircon during exhumation of an UHP terrane requires either an extraordinarily fast rate of denudation (up to 10 cm/year) or continuous refrigeration in an extensional regime (retreating subduction zone).     

Inland saline lakes with lagoonal biota: some reflections on the concept and nature of athalassic (non-marine), paralic and marine saline waters

First, some inland basins with lagoonal (or paralic) biota are brieffly described. The different kinds of saline aquatic environments are then defined and the composition of their biota are discussed. Finally, the still unknown microbiogeochemical composition of concentrated inland waters is discussed. Under arid and endorheic conditions, it seems that the wider and the more geologically complex a hydrological basin is, the more biogeochemically similar to seawater is the water of its terminal lake. The evolution of the microbiogeochemical complexity of seawater through geological times is considered.This paper has been the subject of considerable discussion among referees. Not all of the views expressed by the author are accepted by them.     

World oil: Hotelling depletion or accelerating use?

In theoretical Hotelling-type models of resource depletion, oil use declines monotonically over time to depletion. However, world oil use has been increasing for several years. Can theory and reality be reconciled? The answer is affirmative, if theory is modified to accommodate outward-shifting demand functions that are rising in response to growth in world population and income. Under this assumption, a Hotelling depletion model projects a 50-year period of increasing world oil use before the decline to exhaustion. This holds for both competitive and monopolistic regimes. Hotelling theory has been criticized by Adelman and others, in part because of the unreality of the theoretical projections. By combining the modified Hotelling theory with U.S. Geological Survey resource estimates, the numerical projections seem congruent with Adelman's near-term expectations. Finally, a backstop technology, such as renewable biomass ethanol, introduces a new dimension. Assuming a $2-per-gallon cost for the ethanol, the modified Hotelling theory projects accelerating use of conventional oil until depletion or substitution. Consequently, it does not seem unreasonable to believe that a finite, limited resource of conventional oil is consistent with growing use for several decades. A projected exhaustion in 100 years is consisten with increasing use for 50 years.     

上海城市功能的转型:从全球生产系统角度的透视

本文首先回顾了价值链与全球生产系统的研究进展，结合跨国公司最新发展趋势对全球生产系统特征进行了总结；其次以改革开放以来上海对外贸易结构的改变，描述了90年代以来上海在全球生产系统分工中的变化，认为出口产品结构的转型并没有真正改变上海在国际劳动分工中处于低端环节的地位；最后就上海建设世界城市的差距与优势进行了总结，提出全球化发展的外部力量和地方化响应的内部力量将是上海发展世界城市的两个重要驱动力。     

全球城市理论与中国的国际城市建设

全球城市是多因素作用的结果,研究范式由20世纪70年代的马克思主义政治经济学向全球与地区相互作用的范式转换。全球城市体系的划分从单一指标向经济与文化结合的多指标方向发展。但如何选取指标,如何进行指标的测量,如何确定各指标的权重分配以及如何采集城市间相互作用的数据与资料,都是全球城市研究要面对的重要问题。中国的全球城市建设要从全球城市体系的等级、位序规律出发,根据社会经济发展的实际,要有步骤、有目标、分阶段,稳步推进,逐步提升城市发展的层次,促进城市国际化的步伐,建设中国的国际城市。     

试论世博会后昆明世博园的可持续发展

’99昆明世博会后，如何实现世博园的可持续发展，成为学术界和世博园管理者不可回避、急需解决的现实问题。文章在论述世博园的性质、现状、面临的问题、影响世博园持续发展的因素的基础上，初步提出出世博园可持续发展的对策。     

On Invisible Trade Relations between Mesopotamian Cities during the Third Millennium B.C.

The idea that the emergence of writing was necessity due to the increase in both the number of economic transactions and political complexity has been recently emphasized by Matthews, who also underlines that writing acted as a feedback in enabling and encouraging the growth of ever more complex modes of exchange. The intertwinement of trade and writing suggests that clay tablets left by the civilizations from the third millennium B.C. in Mesopotamia, where writing was invented, may be considered as traces of trade links and transactions between cities. We estimate a gravity model based on clay tablets, as if they represented trade flows. The parameters lead us to conclude that Mesopotamia formed a strongly integrated market.     

1995年世界气候概况

１９９５年，世界气候普遍偏暖。欧亚大陆大部、北美大陆中部、南美大陆中部、非洲西北部的年平均气温大多偏高１－２℃，其中俄罗斯大部、美国西南部显著偏高，部分地区偏高４℃，北半球中高纬度地区冬暖非常显著。由于北半球中纬度地区，许多测站气温高达３５－４０℃，为近几十年乃至百年一遇。年内，全球许多地区旱涝频繁，诸如年初欧洲的暴风雪与美国加利福尼亚洲的特大洪水及夏季朝鲜、与中南半岛的大水灾、加勒比海的飓风等危