Signal preservation

The stable carbon isotope signal preserved in benthic foraminiferal carbonate tests reflects global ocean circulation and organic carbon fluxes. It is also subject to local influences, notably gradients in the isotope ratios of sediment pore-waters ( microhabitat effect ), and vital effects possibly related to the incorporation of metabolic carbon into the shell material (McCorkle et al. 1990 Mackensen Bickert 1999 Schmiedl et al. 2004). Mackensen et al. (1993) recogiuzed a ph)4odetritus effect whereby deviations in 8 C... 

Inevitably the molecular and isotopic signals preserved in sedimentary organic matter are biased. They tend to emphasize or overestimate contributions from those organisms that biosynthesize refactory compounds which survive better in the geological record. Thus, assessment of the relative importance of different biota based on quantification of their diagnostic constituents (58) in sediments may not accurately... 

Effect is linked to receptor signal. Thus, complex physiological patterns may be preserved. 

Independent arrays of telescopes have been discussed for decades but have generally not been successful, except for radio telescopes, where interferometry is a key virtue, aided by the fact that the individual telescope signals can be amplihed and combined while preserving phase information. This is not practical in the optical, thus there are significant inefficiencies in sensitivity by coherently combining the light from an array of optical telescopes. Instrumentation for an array of telescopes has also been a cause of difficulty. Perhaps the best known successful array has been the VLT with four 8-m telescopes, each with its own suite of science instruments, and the capacity to combine all telescopes together for Interferometric measurements. 

The preservation of biogenic isotopic signals ( C, N) in fossil bones and teeth is critical in order to interpret paleodiets. Some patterns of variation of these biogenic isotopic signals are characteristic of modern mammals, and their recognition in fossil samples provides a clue for the preservation of biogenic paleodietaiy signals. 

BIOGENIC ISOTOPIC SIGNALS USED TO ASSESS THE PRESERVATION OF ISOTOPIC SIGNALS IN FOSSIL SAMPLES FROM C3 PLANT FOOD WEBS... 

The approach proposed to check the preservation of isotopic signals in fossil vertebrate bones and teeth is appropriate not only for Pleistocene cold and temperate areas, but also during geological periods before the... 

Preservation of Biogenic Carbon Isotopic Signals in Plio-Pleistocene Bone and Tooth Mineral... 

The properties described above have important consequences for the way in which these skeletal tissues are subsequently preserved, and hence their usefulness or otherwise as recorders of dietary signals. Several points from the discussion above are relevant here. It is useful to ask what are the most important mechanisms or routes for change in buried bones and teeth One could divide these processes into those with simple addition of new non-apatitic material (various minerals such as pyrites, silicates and simple carbonates) in pores and spaces (Hassan and Ortner 1977), and those related to change within the apatite crystals, usually in the form of recrystallization and crystal growth. The first kind of process has severe implications for alteration of bone and dentine, partly because they are porous materials with high surface area initially and because the approximately 20-30% by volume occupied by collagen is subsequently lost by hydrolysis and/or consumption by bacteria and the void filled by new minerals. Enamel is much denser and contains no pores or Haversian canals and there is very, little organic material to lose and replace with extraneous material. Cracks are the only interstices available for deposition of material. 

---