Probability of impact

Test a substantial number of compounds. VS methods generally offer enrichment, but most ranked hit lists contain a significant proportion of false positives. Hitlists should be scaled to 1-5% of the compounds in the virtual library screened. In many real world situations, the computational chemist is being asked to choose lists of compounds representing 0.1% or less of the compounds screened (e.g., the best 100 of 100,000 compounds). Typically, VS methods have been validated considering 1%, 5%, or 10% of the total number of compounds in the VS collection. By following up on more compounds, one increases the probability of impact from VS. 

Smith, E.P., Lipkovich, L, Ye, K. (2002). Weight of Evidence (WOE) Quantitative Estimation of Probability of Impact. Human and Ecological Risk Assessment, 8, 1585-1596. 

In order to estimate the probability of impact of the moistened part of a particle by surrounded particles in the fluidized bed, a simple model was developed [69], As an assumption that the fluidized bed is in an homogeneous condition, a certain portion of the relative porosity is assigned to each particle, and the shape of air covering the particle is taken to be a cube (Fig. 16.16). The entire bed consists of stacked cubes containing a particle at their center. The amount of air - and in consequence the distance between the particles - becomes larger for example, with the same fluidization mass flow the Archimedes number is decreased. The bed will then expand with a greater fluidization throughput and with a constant Archimedes number hence, the distance between the surrounded particles will increase. 

A probability of impact Pr depends on the path length ap between surrounded particles and the relationship of the total projected surface of the surrounded particles AP,in relation to the surface of the sphere Asv,surrounded with the radius ap. 

The probability of impact of particles with the wetted part of their surfaces is the product of both probabilities... 

Because risk assessments are difficult to quantify, another scale, the Palermo technical scale, is often used by astronomers to complement the Torino scale. The Palermo scale offers a more mathematical calculation utilizing the variables of probability of impact and energy of collision. 

Figure 9.2 Quantification of risk for environmental contaminants using probability density functions. The probability of impacts corresponds to the extent of overlap of the estimated environmental concentration (left curve) and the effective toxic concentration (right curve). The risk can be quantified from the distance between the mean values of the concentrations and the variance in the respective concentrations (due to measurement variability and/or extrapolation errors) represented by the width of the distributions. Reproduced from Nendza, Volmer and Klein (1990) with kind permission from Kluwer Academic Publishers, Dordrecht.

Researchers who work on applied research always think about how their ideas can impact the world, both economically and socially. There is no lack of desire on the part of the researcher to see the impact. The idea has to be directed towards solving a burning problem in the world to have an impact. You cannot mandate innovation. However, bringing the knowledge of what the world needs to the innovator will help the innovator make choices that increase the probability of impact. 

When applying nonequilibrium methods it is important not to increase the probability of impact ionization, i.e., the effective temperature of carriers must not be elevated too much. Nonequilibrium methods are used for relatively weak fields, out of the hot electron range, but near to it. 

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