Chemical imbalance models

Colbert, T. (2001). Rape of the soul How the chemical imbalance model of psychiatry has failed its patients. Tustin, CA Kevco. 

Closed chemical imbalance models deal with objects where in the absence of flow chemical equilibrium is not reached. At the basis of such models is the following assumption the flow time At = 0, the relaxation time > 0 and inversely correlates with the reaction velocity. That is why they sometimes are called simply reaction models. 

The pharmaceutical industry employs similar language in its promotional material. An early advertisement for Prozac suggests that Like arthritis or diabetes, depression is a physical illness (Valenstein 1988, reproduced on p. 181). A leaflet produced in 1996 by a consortium called America s Pharmaceutical Research Companies neatly summarises the idea of the chemical imbalance and its relation to a disease-centred model of drug action ... 

The monoamine theory of depression is important because it provides a model for the idea that antidepressant drugs act on the biological basis of depressive symptoms. It forms the basis for the modern idea that depression arises from a chemical imbalance. 

Extensive evidence conclusively demonstrates that another important mechanism of action of adrenotoxicants is the generation of ROS and the imbalance between prooxidants and antioxidants in the cell. The resulting oxidative stress is a mechanism mediating the toxic effects of numerous chemicals in a wide array of cells and organs, in many if not all, animal and plant species. Numerous studies with mammalian models using either in vitro exposures of tissues and cells or whole animal studies,... 

One source of mis-specification is the type of the error process. Homogeneity of variances is typically assumed by standard time series models. However, in the context of chemical production processes e.g. an adjustment of a plant s production rate may lead to an imbalance of the underlying chemical reaction(s). This instability may materialize in fluctuations of the output flow rate(s) which may also affect flow rates in subsequent... 

The preceding chapter deals with methods describing the behaviour of product flows in chemical production plants to model the core components of chemical production networks in detail. The next step in modelling product flows in chemical production networks is to describe product flows between chemical production sites and plants. At a site, intermediate chemicals are produced by some plants and consumed by some other plants whereby raw chemicals are only consumed and final chemicals are only produced. To buffer temporal imbalances of chemical flows, inventories are hold at the sites. Figure 3.1 shows the schematic chemical production network with added inventories symbols and highlighted chemical flows. 

The presence of nonuniform computational tasks whose sizes are not known in advance is often the cause of load imbalance, and quantitative modeling of load imbalance can therefore be difficult to do. However, simulations that involve distribution of nonuniform tasks can sometimes provide empirical data that can be used to model load imbalance. In chapter 7 we will illustrate the use of empirical data to model load imbalance in the computation of the two-electron integrals, which is a required step in many quantum chemical methods. Parallel programs involving uniform computational tasks will experience load imbalance whenever the number of tasks is not a multiple of the number of processes. This kind of load imbalance is easier to include in a performance model because the amount of work assigned to the process... 

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