Effect-cause relationship

Both contamination and pollution entail the perturbation of the natural state of the environment by anthropogenic activity. The two terms are distinguishable by the severity of the effect pollution induces the loss of potential resources. Additionally, a clear cause-effect relationship must be established for a substance to be classified as a pollutant towards a particular organism. 

That some enhancement of local temperature is required for explosive initiation on the time scale of shock-wave compression is obvious. Micromechanical considerations are important in establishing detailed cause-effect relationships. Johnson [51] gives an analysis of how thermal conduction and pressure variation also contribute to thermal explosion times. 

Air quality criteria are cause-effect relationships, observed experimentally, epidemiologically, or in the field, of exposure fo various ambient levels of specific pollutants. The relationships between adverse responses to air pollution and the air quality levels at which they occur have been discussed in Chapter 4 and illustrated in Table 4-5 and Fig. 4-10. 

Ultimately physical theories should be expressed in quantitative terms for testing and use, but because of the eomplexity of liquid systems this can only be accomplished by making severe approximations. For example, it is often neeessary to treat the solvent as a continuous homogeneous medium eharaeterized by bulk properties such as dielectric constant and density, whereas we know that the solvent is a molecular assemblage with short-range structure. This is the basis of the current inability of physical theories to account satisfactorily for the full scope of solvent effects on rates, although they certainly can provide valuable insights and they undoubtedly capture some of the essential features and even cause-effect relationships in solution kinetics. Section 8.3 discusses physical theories in more detail. 

The essential weakness of the correlation approach is that it lacks a linkage to molecular events. A correlation is not a cause-effect relationship. Nevertheless, with sufficient weight of evidence it becomes reasonable to seek an underlying... 

The ANN was able to assimilate the cause-effect relationship of the density of the ester, its structure and temperature. The training and testing results are shown in Fig. 10-14 for individual ester series. The network with the proposed training routine converged in less than 100 iterations for all the esters. 

In this approach, connectivity indices were used as the principle descriptor of the topology of the repeat unit of a polymer. The connectivity indices of various polymers were first correlated directly with the experimental data for six different physical properties. The six properties were Van der Waals volume (Vw), molar volume (V), heat capacity (Cp), solubility parameter (5), glass transition temperature Tfj, and cohesive energies ( coh) for the 45 different polymers. Available data were used to establish the dependence of these properties on the topological indices. All the experimental data for these properties were trained simultaneously in the proposed neural network model in order to develop an overall cause-effect relationship for all six properties. 

In evaluating the influence of individual climate controls, we have three major concerns the time frame over which the control operates, the potential magnitude of the control s influence on climate, and whether a strong correlation between some forcing phenomenon and climatic response actually indicates a cause-effect relationship. 

The easiness of the DSS to explore the problem at hand, to derive possible solutions, and discover and analyse the cause-effect relationships... 

Alfuzosin has been linked to two cases of hepatitis.2930 The cause-effect relationship remains to be elucidated. 

It has been known for many years that elevated levels of serum cholesterol are associated with atherosclerosis, although the cause-effect relationship remains unproven. A rather straightforward therapeutic regimen intended for prevention or arrest of the progress of this disease involves lowering levels of serum cholesterol in the high-risk population. 

In summary, models can be classified in general into deterministic, which describe the system as cause/effect relationships and stochastic, which incorporate the concept of risk, probability or other measures of uncertainty. Deterministic and stochastic models may be developed from observation, semi-empirical approaches, and theoretical approaches. In developing a model, scientists attempt to reach an optimal compromise among the above approaches, given the level of detail justified by both the data availability and the study objectives. Deterministic model formulations can be further classified into simulation models which employ a well accepted empirical equation, that is forced via calibration coefficients, to describe a system and analytic models in which the derived equation describes the physics/chemistry of a system. 

The framework around which the cause-effect relationships in CSD have been studied is generally referred to as structural evolution. This name has been used, in part, because structural rearrangement at various length scales typically occurs during the transitions from solution species to the final desired him, as outlined in Fig. 2.1.16... 

Because of the complexities involved in understanding cause-effect relationships, an alternative approach to control the thin film microstructure has been pursued by some investigators—the use of statistically designed experiments to identify key processing parameters.114115 In these approaches, as illustrated in Table 2.6 for a Plackett-Burman screening study,114 limiting values for various experimental parameters are chosen. Films are then prepared from solutions synthesized under these conditions, and resulting film... 

Researchers who have focused more on understanding cause-effect relationships in solution processing have given attention to film drying and pyrolysis behavior, densification processes, and nucleation and growth into the desired crystalline state. Both thermodynamic and kinetic factors associated with the phase transformation from the amorphous state to the crystalline state have been considered.11 119 Control of these factors can lead to improvements in the ability to influence the microstructure. It is noted that in the previous sentence, influence has been carefully chosen, since the ability to manipulate the factors that govern the nature of the phase transformation to the extent that full control of the microstructure is possible remains to be demonstrated. However, trends in characteristics such as film orientation and columnar versus uniaxial grains have certainly already been achieved.120... 

Finally, the pesticide concentrations determined in water and biota, together with the toxicity values of each individual compound, the toxicity data measured in the water samples, and the general physicochemical values were combined and analyzed together to establish potential cause-effect relationships and identify major toxicants or environmental pressures in the area of study. More details can be found in Kock et al. [12],... 

To provide a better understanding of toxic impacts on aquatic ecosystems, cause-effect relationships between changes in biodiversity and the impact of environmental pollution as causative factor as well as the underlying processes. This included the assessment of sub-lethal effects in vitro and in vivo as early warning strategies and of their strength to predict potential hazards to the ecosystem. 

Metabolic and physiological approaches in the detection of cause-effect relationships may be useful in the early assessment of stressors on biofilms. Physiological responses may be much faster and might reflect transient effects on the biofilms, while those that are more persistent may be reflected in the structural components (Fig. 10). 

In view of these complexities, environmental studies that seek to verify proposed cause-effect relationships between contamination and response need to be carefully designed to avoid bias and misunderstanding. Most environmental assessments adopt a multi-tiered approach to testing, in which combinations of biological responses (biomarkers) are measured in tissue samples, body fluids or at the whole organism level to indicate exposure to or adverse effects of contamination.8. Auffret and colleagues60 surveyed Pacific oysters from the Atlantic coast of Brittany after the Erika oil spill between... 

Whether LSD causes dysmorphogenesis is also difficult to evaluate. A third case of multiple ocular abnormalities was reported in a premature infant of a mother who had used LSD sporadically, as well as other drugs, such as cocaine and heroin. No definite cause-effect relationship could be drawn (14). 

Subsequently, three methods indicating safety risks will be evaluated on these nine criteria discussed above whether indirect safety related operational deviations are used, general conclusions can be derived, detailed cause-effect relationships are available, the method is feasible, the results are reliable, only limited resources are needed, the results can be ranked, a clear link between risk reduction and operational benefit is present, and if all (root)cause areas are included. 

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