Sedimentary rocks from the saline formation of the Lopare Basin were investigated. Sediments contain a moderate amount of immature to marginally mature algal organic matter deposited under slightly reducing to anoxic and slightly saline to hypersaline conditions. Almost all of the samples contain β-carotane in a relatively high quantity, and in some, it represents the most abundant compound in the total distribution of hydrocarbons. The objective of the study was to determine the conditions that are favourable to precursors of β-carotene and/or the preservation of the carotenoid hydrocarbon skeleton. Moreover, the dominant transformation pathways of β-carotene under different redox and salinity conditions, which lead to the formation of aromatic carotenoids were defined. 相似文献
Consideration of within-earthquake ground-motion correlation is essential for the estimation of seismic hazards, damage, and loss for spatially distributed systems. In many seismically active regions, the strong motion data of real engineering significance are completely unavailable or very scarce. The absence of necessary data does not allow developing regional empirical correlation models, and the models obtained for other regions should be used with correspondent sensitivity analysis. The level of within-earthquake correlation may vary in broad range; therefore, development of correspondent criteria for selection from available models is important. In this paper, we analyzed the performance of a system of critical elements of electric power network (substations) depending on variations in within-earthquake correlation. The performance is described as probability of different levels of non-functionality, i.e., percentage of area suffering power outage, and probability of expected number of customers without power. We have shown that the proper choice of the within-earthquake correlation model is critical in comprehensive estimations of functionality of substations in electrical power system. Skipping the ground-motion variability and within-earthquake correlation may lead to unreliable results. Relevance of geology-based within-earthquake correlation models has been demonstrated, and a scheme, which allows reducing uncertainty in the choice of realistic correlation, has been proposed. 相似文献
正Salt Lake is one of the lakes in the system,consisting of a huge amount of salt and bitter-salty lakes in Novosibirsk Oblast and Altai Krai.These lakes are unique and highly unstable systems where the parameters of geochemical 相似文献
正1 Introduction Alkaline Lake Khilganta located in a steppe zone of South Siberia(N 50°42'535,E 115°06'086)is unique among adjacent lakes because of a development of a thick(up to 3 cm)cyanobacterial mat dominated by 相似文献
Vertical impacts on the Earth of asteroids 500-3000 km in diameter at 15 km/s have been numerically modelled using the hydrodynamic SOVA code. This code has been modified for the spherical system of coordinates well suited for simulations of very large impacts when the entire Earth is involved in motion. The simulations include cratering process, upward motion of deep mantle layers, fall of ejecta on the Earth, escape of matter to space, and formation of rock vapour atmospheres. The calculations were made for the period preceding disappearance of rock vapour atmospheres caused by radiation several years after the largest impacts. For very large vertical impacts at 15 km/s, escaping masses proved to be negligibly small. Quantities of kinetic, internal, potential, and radiated away energies are obtained as functions of time and space. After the impacts, a global layer of condensed ejecta covers the whole of the Earth's surface and the ejecta energy is sufficient to vaporise an ocean 3 km deep. The mass of rock vapour atmosphere is 10-23% of the impactor mass. This atmosphere has a greater mass than the water atmosphere if impactor is 2000 km in diameter or larger. 相似文献
Drought and water scarcity can significantly impair the sustainable development of groundwater resources, a scenario commonly found in aquifers in the Mediterranean region. Water management measures to address these drivers of groundwater depletion are highly relevant, especially considering the increasing severity of droughts under climate change. This study evaluates the potential of managed aquifer recharge (MAR) to offset the adverse effects of drought and water scarcity on groundwater storage. Los Arenales aquifer (central Spain), which was unsustainably exploited for irrigation in the second half of the twentieth century, is employed as a case study. Two neighbouring zones within this aquifer are contrasted, namely, Los Arenales (LA) and Medina del Campo (MC). The primary difference between them in terms of water resources management is the wide-scale implementation of MAR systems in LA since the early 2000s. Several groundwater statistical methods are used. Groundwater-level trend analysis and average piezometric levels show in LA a faster recovery of aquifer storage and less susceptibility to drought compared to MC. On the other hand, standardised precipitation indexes and standardised groundwater level indexes of detrended groundwater-level time series, which do not include the effects of MAR, show that LA can be more negatively affected by drought and groundwater abstraction. The sharper recovery of piezometric levels in LA when considering MAR, and bigger drought impacts observed when the effects of this measure are removed, demonstrate that MAR can effectively alleviate the impacts of water scarcity and drought, providing an adaptation solution to climate change worldwide.
With 80 % of world trade carried by sea, seaports provide crucial linkages in global supply-chains and are essential for the ability of all countries to access global markets. Seaports are likely to be affected directly and indirectly by climatic changes, with broader implications for international trade and development. Due to their coastal location, seaports are particularly vulnerable to extreme weather events associated with increasing sea levels and tropical storm activity, as illustrated by hurricane “Sandy”. In view of their strategic role as part of the globalized trading system, adapting ports in different parts of the world to the impacts of climate change is of considerable importance. Reflecting the views of a diverse group of stakeholders with expertise in climate science, engineering, economics, policy, and port management, this essay highlights the climate change challenge for ports and suggests a way forward through the adoption of some initial measures. These include both “soft” and “hard” adaptations that may be spearheaded by individual port entities, but will require collaboration and support from a broad range of public and private sector stakeholders and from society at large. In particular, the essay highlights a need to shift to more holistic planning, investment and operation. 相似文献