Variables, environmental

While participating in the European Union programme on risk assessment of existing chemicals, Euro Chlor (representing all major European chlorine producers), recognised the need to carry out a detailed risk evaluation on chemicals linked to the production of chlorine. In view of concerns about specific risks of organohalogen compounds to the marine environment as a sink for all watercourses, Euro Chlor focused on this environmental compartment, with emphasis on the North Sea. This sea area has been extensively studied and is controlled by the Oslo and Paris Convention for the Prevention of Marine Pollution (OSPARCOM). For a series of chemicals on lists of concern adopted by the North Sea Conference (1990), risk assessments are being carried out to demonstrate their variable environmental profiles. 

Ca salts differ from one another in terms of the anions and molecules that they are associated with. CCM s characteristic aqueous solubility is directly related to the citrate and malate anions. The in vitro solubility of any Ca salf is essenfially constant under standard conditions (e.g., at neutral pH in water). Once a Ca source is consumed, it encoimters a host of variable environmental factors, such as pH changes, interactions with other food components, and the hormonal milieu, that alter its solubility and/or potential for absorption. It is the net impact of these internal factors, together with the combination of introduced variables, such as the food matrix in which Ca is incorporated and the timing of Ca intake, that contribute to determining just how beneficial to health a Ca source will be. 

Nonlinear interaction causes the redistribution of energy within the spectrum. These processes are described by the source functions Sn. The time and length scales of the variable environmental parameters (wind, depth, current) must be large compared to those of the... 

In the context of enzymes, various mechanisms allow adaptation to fluctuating environmental conditions. Most importantly, mechanisms for transcriptional control and allosteric regulation have evolved to modulate enzyme expression and activities and the consequent fluxes through metabolic pathways in response to environmental perturbations. Another mechanism for adaptation to variable environmental conditions is evolution of isozymes that catalyze a common reaction, but function optimally under different conditions. 

DA Kalman, J Hughes, G van Belle, T Burbacher, D Bolgiano, K Coble, NK Mot-tet, L Polissar. The effect of variable environmental arsenic contamination on urinary concentrations of arsenic species. Environ Health Perspect 89 145-151, 1990. 

During photosynthesis a fine control of enzymes is required for the Calvin cycle to operate at the variable environmental conditions, a plant leaf is exposed to. We have shown earlier that the stromal FBPase is controlled in its activity by its product Fru-6-P (l). This effect is very specific, Sed-7-P has no marked effect on the enzyme. The question arose whether such a feedback control also applies to SBPase. 

A vibration monitoring system can be used for periodic or permanent condition assessment. Whatever the case may be, spontaneous changes of modal properties due to variable environmental conditions (e.g. temperature) have to be taken into account ... 

Human hair is usually categorised ethnically into three major distinct groups Asian, Caucasian and African. Looking from the perspective of biological variability, environmental effects and diversity of fibre texture, it is remarkable how uniformly the amino acid makeup of protein components is across ethnic groups. The amino acid makeup of the protein components was reviewed by Wolfram and is depicted in Fig. 1 [1, 2, 18, 19]. 

Asteatotic irritant eczema Slowly developing Adapted from Chew and Maibach [37] Variable Environmental (winter, dry)... 

Figure 11 shows kinetic curves of adhesion of Aspergillus niger spores to the surface of polyethylene at constant temperature and variable environmental humidity. The constants of adhesion, which were calculated at different humidifies and collected in Table 11, showed remarkable changes in k values as changes were sufficiently small. 

Accumulation of PAHs occurs in all marine organisms however, there is a wide range in tissue concentrations from variable environmental concentrations, level and time of exposure, and species ability to metabolize these compounds. PAHs generally partition into lipid-rich tissues, and their metabolites can be found in most tissues. In fish, liver and bile accumulate... 

B5hme, R, K. Welsch-Pausch, and M.S. McLachlan. 1999. Uptake of airborne semivolatile organic compounds in agricultural plants Field measurements of interspecies variability. Environmental Science <6 Technology, 33 1805-1813. 

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