ICEBERG EFFECT

The final phase of the accident sequence and the last link in the chain reaction is costs. All contacts result in some form of loss. Losses could include both direct and indirect costs of the accident. Model 2.7 shows the iceberg effect where the property damage costs could be 60 to 100 times greater than the direct costs. The totally hidden costs of the accident also are losses that are hard to determine, but which exists nevertheless. 

Total cost of ownership rather than price is used here because in most transactions there will be costs other than the purchase price involved. For example, inventory carrying costs, maintenance costs, running costs, disposal costs and so on, In business-to-business markets particularly, as buyers become increasingly sophisticated, the total costs of ownership can be a critical element in the purchase decision. Life-cycle costs , as they are referred to in the military and defence industries, have long been a critical issue in procurement decisions in those markets. Figure 2.1 shows the iceberg effect of total costs of ownership where the immediate purchase price is the only aspect of cost that is visible, whereas below the surface of the water are all the costs that will arise as a result of the purchase decisions. 

It may be assumed, however, that the usual negative study "iceberg effect" applies for every negative finding which surfaces in a published report, a much larger number of unpiibllshed negative results exists. 

The ideas of Frank, Evans and Kauzmann had a profound influence on the way chemists thought about hydrophobic effects in the decades that followed However, after the study of the hydrophobic hydration shell through computer simulations became feasible, the ideas about the hydrophobic hydration gradually changed. It became apparent that the hydrogen bonds in the hydrophobic hydration shell are nof or only to a minor extent, stronger than in normal water which is not compatible with an iceberg character of the hydration shell. 

Fan XT, Toivonen PMA, Rajkowski KT and Sokorai KJB. 2003. Warm water treatment in combination with modified atmosphere packaging reduces undesirable effects of irradiation on the quality of fresh-cut iceberg lettuce. J Agric Food Chem 51(5) 1231—1236. 

The sketched examples represent just the tip of the iceberg called heterogeneous catalysis. An excellent account of the historical development as well as of the current state of the art can for example be found in a recent review by J. M. Thomas. [30] A few of the additional effects for which understanding can also be sought on the basis of file surface science approach will only be briefly listed ... 

Fukumoto, L. R., Toivonen, P. M., and Delaquis, P. J. (2002). Effect of wash water temperature and chlorination on phenolic metabolism and browning of stored iceberg lettuce photosynthetic and vascular tissues. ]. Agric. Food Chem. 50,4503 4511. 

Koseki, S. and Isobe, S. (2006). Effect of ozonated water treatment on microbial control and on browning of iceberg lettuce (Lactuca sativa L.).. Food Prot. 69,154-160. 

Many of the different factors discussed in this section that together make up the observed toxicity of a chemical (e.g. acute versus chronic administration, assays in vitro versus in vivo, the effects of substituents or metabolism) will be illustrated with heterocyclic chemicals in the following section. However, as mentioned in the Introduction, they are but the tip of the iceberg with respect to the structure-toxicity relationships awaiting discovery within this subgroup of organic chemicals. 

Measurement of AH0 and AS0 showed that the former is small and positive and the second is large and positive. This implies that micelle formation is entropy driven and is described in terms of the hydrophobic effect (14). Then hydrophobic chains of the surfactant monomers tend to reduce their contact with water, whereby the latter form icebergs by hydrogen bonding. This results in reduction of the entropy of the whole system. Flowever, when the monomers associate to from micelles, these icebergs tend to melt (hydrogen bonds are broken), and this results in an increase in the entropy of the whole system. 

The discoveries of Csp s and trigger factor may represent the tip of a large iceberg. In view of the pervasive effects of low temperature on the structures of all classes of macromolecules, it is reasonable to conjecture that many more types of proteins will be discovered whose roles are to offset the effects of cold shock on the cell. Some of these molecules may be expressed constitutively and may be part of the normal machinery of the cell. For example, certain ribosomal proteins are thought to function as RNA chaperones, and if present in sufficient amounts, these proteins may allow the cell to cope with the effects of cold shock on the structures of certain classes of RNAs. In yeast, a constitutively expressed ribosomal protein has helicase activity, and mutation in the gene encoding the protein confers on the cells a cold-sensitive phenotype (Schmid and Linder, 1992). Perhaps the apparent absence of cold-induced RNA chaperones in eukaryotic cells is... 

Hydrophobic effect — Effect that nonpolar compounds possess a low solubility in water. The reason for the low solubility is that nonpolar compounds when they dissolve in water destroy the water structure (hydrogen bonds) because of cavity formation, what is accompanied by a loss of entropy, and the water molecules are forced to order around the solute molecule ( iceberg structure), which is a further loss of entropy. These entropy losses are not compensated for by formation of strong bonds between the solute and water, as it happens in case of polar molecules or esp. in case of ions. 

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