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Hydrogeology Journal - 相似文献
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Kristof Plankensteiner Bernd M. Rode Tomas Mikoviny Armin Hansel Georg Fischer Helmut O. Rucker 《Icarus》2007,187(2):616-619
Saturn's moon Titan has been considered as one of the few places in our Solar System, where atmospheric and surface conditions could have produced organic compounds essential as precursors for an evolution of life. The Cassini-Huygens mission has provided new data on Titan's atmosphere and surface, which enabled us to simulate the chemical processes occurring under these conditions. Possible lightning events on Titan cannot only produce higher hydrocarbons, but also allow surface water ice to participate in the reaction scenario, resulting in CHO, CHN, and CHON compounds including several molecules relevant for the formation of amino acids and nucleic acids. 相似文献
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This article takes its point of departure in the assumption that values shape planning practices and that alternatively one can reconstruct such values from the way planning interventions are argued and evaluated. We contend that planners’ discourses involve implicit value commitments that are observable in their representations of public space and implicated in the results of public-space planning. The paper builds an empirical case from representations of public space elaborated in planning documents developed by planners in four medium-sized Nordic cities. We show how these planning representations form four thematic value clusters concerning urban public space, namely leisure-play, identity-unity, power-organization and unruliness-change. Together these clusters constitute a value framework which reveals a number of central tensions relating to the way that planners seek to balance order and spontaneity in public space. The paper concludes by outlining and discussing these values and the tensions they represent. 相似文献
25.
Lisbeth Lolk Johannsen Nives Zambon Peter Strauss Tomas Dostal Martin Neumann David Zumr 《水文科学杂志》2020,65(4):524-535
ABSTRACTOptical disdrometers can be used to estimate rainfall erosivity; however, the relative accuracy of different disdrometers is unclear. This study compared three types of optical laser-based disdrometers to quantify differences in measured rainfall characteristics and to develop correction factors for kinetic energy (KE). Two identical PWS100 (Campbell Scientific), one Laser Precipitation Monitor (Thies Clima) and a first-generation Parsivel (OTT) were collocated with a weighing rain gauge (OTT Pluvio2) at a site in Austria. All disdrometers underestimated total rainfall compared to the rain gauge with relative biases from 2% to 29%. Differences in drop size distribution and velocity resulted in different KE estimates. By applying a linear regression to the KE–intensity relationship of each disdrometer, a correction factor for KE between the disdrometers was developed. This factor ranged from 1.15 to 1.36 and allowed comparison of KE between different disdrometer types despite differences in measured drop size and velocity. 相似文献
26.
Estelle Turpin Christa Fittschen Alexandre Tomas Pascal Devolder 《Journal of Atmospheric Chemistry》2003,46(1):1-13
We have determined the 2-oxo-propyl CH3C(O)CH2 (sometimes called 1-methylvinoxy or acetonyl) radical yield for the reaction of acetone with OH radical relative to the 2-oxo-propyl yields for the reactions of F- and Cl atoms with acetone using the Discharge Flow technique. The 2-oxo-propyl radical has been monitored by Laser Induced Fluorescence LIF at short reaction times in the systems: OH + acetone (R1), F + acetone (R2), and Cl + acetone (R3). From these measurements we have deduced the branching ratio for the 2-oxo-propyl radical formation in the title reaction to be in the range 0.8 R 1. 相似文献
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The diet and egg production rate ofAcartia tonsa were measured during the thermally stable period between June and October 1995 at four locations in inner and outer Florida Bay. We sought to characterize the role ofA. tonsa in the bay’s pelagic food web, which has been changing since 1987, when the dominant submerged vegetation began shifting from benthic seagrasses to planktonic algae. At Rankin Lake, a shallow basin on the north side of the inner bay, where extensive seagrass mortality and persistent cyanobacteria blooms have occurred, microplankton biomass was relatively high and dominated by heterotrophic protists and dinoflagellates. Nanoplankton at Rankin, Lake, while numerically abundant, usually contributed only a small portion of the biomass. The ingestion rate ofA. tonsa in Florida Bay varied independently of food concentration (i.e., total microplankton biomass), but rates were higher (mean±SD =3.88 ± 0.73 μg C copepod?1 d?1) on the north side of the bay than on the south side (0.78 ±0.11 μg C copepod?1 d?1). Microzooplankton and dinoflagellates were important dietary constituents, especially in the vicinity of Rankin Lake. Egg production in this region (mean ± SD = 14.2 ± 7.7 eggs female?1 d?1) was considerably high than the baywide mean (5.8±0.81 eggs female?1d?1), and principal components analysis revealed associations between egg production and both dietary microzooplankton and dinoflagellate biomass. However, although grazing rates were relatively high in the inner bay,A. tonsa removed only 1–6% of the primary production from the water column during the summer and its egg production rates were low relative to typical rates for the species. 相似文献
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In this paper, benefits from increasing cross-border cooperation under future CO2 commitments in the Nordic countries are examined and evaluated. Four cooperative strategies are analyzed and valued separately: cross-border electricity trade, cross-border emission-permit trade, the introduction of a trans-Nordic natural gas transmission grid, and, finally, utilization of all these three strategies simultaneously. The valuation is done under varying CO2 commitments and under three different scenarios for future energy demand and technological development. In conducting this analysis, the energy-systems model-generator MARKAL (MARKet ALlocation) was used to model the Nordic energy system. It is shown that all cooperative strategies do lower the abatement costs considerably, especially if the strategy including full cooperation is utilized. In this case, additional costs from meeting CO2 targets may be at least halved for commitments less than 10% reduction until 2050 based on emissions in 1995. No significant difference between low and high CO2 commitments could be observed in the size of the benefits from cooperation, expressed in billions (109) of Swedish crowns. Benefits from cooperation are generally larger for scenarios including relatively higher future energy demand. 相似文献
30.
Application of geochemical and stable isotopic tracers to investigate groundwater salinity in the Ochi-Narkwa Basin,Ghana 总被引:1,自引:1,他引:0
Samuel Y. Ganyaglo Shiloh Osae Tetteh Akiti Thomas Armah Laurence Gourcy Tomas Vitvar 《水文科学杂志》2017,62(8):1301-1316
Rainwater, groundwater and soil-water samples were analysed to assess groundwater geochemistry and the origin of salinity in the Ochi-Narkwa basin of the Central Region of Ghana. The samples were measured for major ions and stable isotopes (δ18O, δ2H and δ13C). The Cl? content in rainwater decreased with distance from the coast. The major hydrochemical facies were Na-Cl for the shallow groundwaters and Ca-Mg-HCO3, Na-Cl and Ca-Mg-Cl-SO4 for the deep groundwaters. Groundwater salinization is caused largely by halite dissolution and to a minor extent by silicate weathering and seawater intrusion. Stable isotope composition of the groundwaters followed a slope of 3.44, suggesting a mixing line. Chloride profiles in the soil zone revealed the existence of salt crusts, which support halite dissolution in the study area. A conceptual flow model developed to explain the mechanism of salinization showed principal groundwater flow in the NW–SE direction.
EDITOR D. KoutsoyiannisASSOCIATE EDITOR K. Heal 相似文献