Disturbance signature

Alteration is always a cause for concern in geochemical investigations and the best approach will always be to avoid samples with visual or chemical evidence for alteration. The differential fluid mobility of U, Th, Pa and Ra undoubtedly provides the potential for weathering or hydrothermal circulation to disturb the U-series signatures of arc lavas. In a study of lavas from Mt. Pelee on Martinique, Villemant et al. (1996) found that domeforming lavas were in U-Th equilibrium whereas plinian deposits from the same eruptions had small U-excesses which they interpreted to reflect hydrothermal alteration. However, whilst the addition of U could be due to hydrothermal alteration, the plinian deposits were also displaced to lower °Th/ Th ratios which cannot. Instead, the two rock types may just be from separate magma batches. 

The concept of ecological disturbance evaluations (EDEs) is another approach to address causation. EDE is conceptually comparable to TIE and BDF. As with TIE and BDF, which are used to identify chemicals responsible for toxicity in whole effluents and contaminated sediments, an EDE is applied after an impact has been detected in a community. The EDE uses an integrated index (e.g., index of biotic integrity), or other metric, allowing the researcher to extract information that might represent a response signature for the suspected cause of the impact. 

Fore LS. 2003. Biological assessment of mining disturbance on stream invertebrates in mineralized areas of Colorado. In Simon TP, editor. Biological response signatures indicator patterns using aquatic communities. Boca Raton (FL) CRC Press, p 347-370. 

Electrocardiographic Signature of OPs Disturbances in the electrical activity of the heart caused by xenobiotics are readily discernible in a surface electrocardiogram (Yurumez et al, 2008 Dalvi et al, 1986 Chuang et al, 1996 Chhabra et al, 1970). 

Frei, R., Bridgwater, D., Rosing, M. Stecher, O. 1999. Controversial Pb-Pb and Sm-Nd isotope results in the early Archaean Isua (west Greenland) oxide iron formation preservation of primary signatures versus secondary disturbances. Geochimica et Cosmochimica Acta, 63, 473-488. 

These are remarkable stabilizations and the absence of any signatures of charge transfer suggests that the electronic states of the components are only disturbed minimally. 

Equations (5.91) and (5.92) help one to understand the physics of instability. The real part of v is proportional to k (Eq. (5.91)) this is the signature of convective heat transport in the air channel. Air flow induces propagation of disturbance along the channel with the same group and... 

Surface selection rules for SERS are generally different from that for NRS, as the symmetry of the molecular nuclear and/or electron arrangement may be disturbed or even broken at the surface. Thus, the orientation of the molecule relative to the surface normal is important and can be detected flat versus tilted versus perpendicular orientations give rise to distinct SERS signatures since the various vibrational bands of the adsorbed molecule, e.g., bands due to in plane and out of plane modes of an aromatic compound are differently enhanced according to the corresponding components of the tensor ttmoiecuie-... 

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