Survival threshold value

Bedaux and Kooijman 1994 Kooijman 1996 Newman and McCloskey 1996, 2000 Zhao and Newman 2007). This is not just an academic discussion the 2 theories lead to different time courses of mortality at constant exposure (Kooijman 1996) (see Figure 2.10) and have very different consequences for sequential exposure (Newman and McCloskey 2000 Zhao and Newman 2007). In reality, both sensitivity difference and stochasticity are likely to play a role in mortality. Individuals also differ in sensitivity, especially in field populations, but there is clearly a substantial stochastic component involved in mortality that cannot be ignored. The method to deal with stochastic events in time is survival analysis or time-to-event analysis (see Bedaux and Kooijman 1994 Newman and McCloskey 1996). For industrial practices, this method has a long history as failure time analysis (see, e.g., Muenchow 1986). Bedaux and Kooijman (1994) link survival analysis to a TK model to describe survival as a function of time (i.e., the hazard rate is taken proportional to the concentration above a threshold value). Newman and McCloskey (1996) take an empirical relationship between external concentration and hazard rate. 

The sensitization threshold is at half-wave potential -0.50 V of a sensitizer with displacement E1/2 to more positive region the sensitizing properties of nitroazoles are nonlinearly growing (see Table 3.43) [919], The best sensitizing properties are marked on nitroazoles, reduced in the potentials E1/2 range from -0.2 to -0.35 V. A linear dependence has been found out between one-electron redox potentials of nitroimidazoles and - log 1/R37 values (r=0.96, n=6). Parameter R37 characterizes an activity of a drug (37% of DNA X174 population survival) [919],... 

We observe threshold effects at different temperatures both for the slow decay constants r2 and in the fraction of surviving carbynes after the thermal treatment Rq. This has a value of roughly 29% after the metastable decay at RT, it drops at 15% at lOO C remaining constant up to 150°C. We observe another drop to 8% at 200°C. This suggests the presence of two activated processes with energy barriers situated between 25 and 40meV. 

The rationale for the choice of the annual average guideline value of 10 pg/m for PM2.5 was that it represents the lower end of the range over which significant effects on survival have been observed in the American Cancer Society Study (ACS) (Pope et al. 2002). Further discussion on this can be found in the document (WHO 2005), which also concludes that although adverse effects on health cannot be entirely ruled out even below that level, it is a level achievable in urban areas of developed countries, and therefore attainment to it is expected to effectively reduce the health risks. However, the experts emphasized the need to reduce exposure to non-threshold pollutants such as particulate matter, even where current concentrations are close to or below the proposed guidelines. 

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