نتایج جستجو برای: trace fossil
تعداد نتایج: 91986 فیلتر نتایج به سال:
One of the main current concerns regarding soil quality is the presence of trace metals that constitutes a risk of toxicity for plants and animals [1, 5, 7, 11]. Trace metals in soils can have either a lithogenic origin when they inherit from the lithosphere or an anthropogenic origin when they result from man’s activities (mining, metallurgy of non-ferrous metals, combustion of fossil energy s...
Leaf traces are important structures in higher plants that connect leaves and the stem vascular system. The anatomy and emission pattern of leaf traces are well studied in extant vascular plants, but remain poorly understood in fossil lineages. We quantitatively analysed the leaf traces in the late Permian conifer Ningxiaites specialis from Northwest China based on serial sections through pith,...
1. Basic Concepts 1.1. Air Pollution 1.2. Criteria and Non-Criteria 1.3. Emissions 2. The Epidemiological Model 3. Toxic Trace Elements from Fossil Fuel Combustion 4. Environmental Behavior of Metal Pollutants 4.1. Atmospheric Aerosol Particles 4.2. Aqueous and Marine Environments 4.3. Accumulation of Heavy Metals in Marine Invertebrates 4.4. Heavy Metal ions in Soils 4.5. Methylation of Heavy ...
Ten international laboratories participated in an inter-laboratory comparison of a fossil bone composite with the objective of producing a matrix and structure-matched reference material for studies of the bio-mineralization of ancient fossil bone. We report the major and trace element compositions of the fossil bone composite, using in-situ method as well as various wet chemical digestion tech...
Direct quantification of fossil fuel CO2 (CO2ff) in atmospheric samples can be used to examine several carbon cycle and air quality questions. We collected in situ CO2, CO, and CH4 measurements and flask samples in the boundary layer and free troposphere over Sacramento, California, USA, during two aircraft flights over and downwind of this urban area during spring of 2009. The flask samples we...
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