Causality


The result is (causality dictates the upper limit of time integration to t)  [c.718]

Contrary to what appears at a first sight, the integral relations in Eqs. (9) and (10) are not based on causality. However, they can be related to another principle [39]. This approach of expressing a general principle by mathematical formulas can be traced to von Neumann [242] and leads in the present instance to an equation of restriction, to be derived below. According to von Neumann complete description of physical systems must contain  [c.111]

A set of properties of states (causality, resh ictions on the spectra of self-energies, existence or absence of certain isolated energy bands, etc.).  [c.111]

The equation of restriction can embody causality, lower boundedness of energies in the spectrum, positive wavenumber in the outgoing wave (all these in nonrelativistic physics) and interactions inside the light cone only, conditions of mass speciality, and so on in relativistic physics. In the case of interest in this  [c.111]

If possible, there should be measurement of the toxic effect in order quantitatively to relate the observations made to the degree of exposure (exposure dose). Ideally, there is a need to determine quantitatively the toxic response to several differing exposure doses, in order to determine the relationship, if any, between exposure dose and the nature and magnitude of any effect. Such dose—response relationship studies are of considerable value in determining whether an effect is causally related to the exposure material, in assessing the possible practical (in-use) relevance of the exposure conditions, and to allow the most reasonable estimates of hazard.  [c.226]

The relationship set out in Eq. (9-115) can also be viewed via a different chain of causality with (DCFRR) as a given parameter, (PBP) as the independent variable, and n as the variable whose value is being sought. Such an approach is the basis for the lines in Fig. 9-31, each of which shows the number of years of projec t life required to achieve an effective interest rate or a (DCFRR) of 20 percent by projects having various payback periods. The three hues differ from each other with respec t to the matter of inflation.  [c.834]

Although, as previously noted, interest in phytoestrogens arose from the detection of adverse effects in a number of domestic and other species, there is a lack of evidence of obvious adverse effects in human populations that have traditionally consumed diets high in fruits or vegetables (e.g. the Asian countries). There are only isolated reports of adverse oestrogen-related effects, for example menstrual disorders in Dutch women who apparently consumed large quantities of tulip bulbs during the Second World War. ° However, even here the effects have not been established as being causally related to phytoestrogens. The human experimental and epidemiological evidence is generally supportive of the beneficial nature of a diet rich in foodstuffs containing phytoestrogens. Thus, it might at first sight be surprising that concerns have been expressed over the potential for phytoestrogens to cause adverse effects.  [c.129]

In a cross-sectional study, exposure and effect are studied simultaneously. This approach contains an inherent problem because exposure must precede the effect. However, it can he used to investigate acute effects and also mild chronic effects (which do not force people to leave their jobs) if exposure has remained rather stable for a long time. When the prevalence of the effects studied are compared with the prevalence in other worker groups (controls or references) which correspond otherwise with the study group but are not exposed to the agent investigated, indicative evidence of possible causality may be obtained. For example, cross-sectional studies have been applied successfully to reveal the associations between mild neurotoxic effects and exposure to organic solvents.  [c.242]

We have seen, for instance, how worker experience can compensate for increasing age. Management factors such as commitment to safety can also affect the way that workers wiU trade-off productivity and safety and thus make use of safety procedures and work permits. Other examples can be drawn from the interaction of control panel design and procedures or training. Grouping of process information, for instance, is related to the type of strategy that is adopted, which in turn is dependent on the type of procedures and training provided. The indicators of the same pressure valve on two different reactors are, in one sense, highly similar. Yet, in another sense, their similarity is low when compared to the similarity between the valve indicator and the pressure indicator on the input side of a reactor. The latter indicators, belonging to a single system, are more likely to be causally related in a failure and thus belong to the same fault cluster. The optimum way of structuring control  [c.148]

In previous sections of this chapter, the required characteristics of effective causally based data collection systems to reduce human errors and accidents have been described. In this final section, the stages of setting up such a system in a plant will be described.  [c.289]

Rasmussen, J. (1990). Human Error and the Problem of Causality in Analysis of Accidents. In D. E. Broadbent, J. Reason, A. Baddeley (Eds.). Human Factors in Hazardous Situations. Oxford, U.K. Clarendon Press.  [c.374]

Energy theorists of cultural evolution are concerned with the whole sweep of cultural evolution, from prehistoric hunters and gatherers to modern industrial societies. This global, secular perspective is useful in assessing the relevance of ideas advanced to account for short periods of time in the histoi y of particular societies. Those who propose an energy theoi-y of cultural evolution emphasize the problem of causality-whether or not the amount of energy a  [c.309]

For all times t > Tr, the initial and final states of the system will be causally disconnected.  [c.175]

Because of the assumed (temporal depth of two) nature of the reversibility of the underlying universal CA, causality takes on a decidedly non intuitive character the state of a given site is completely determined by the states of its nearest neighbors in space-time. Letting ag t represent the state of the site at x and time t,  [c.667]

The result is that while there is, in DM, something that might be called an information cone centered at each site, it is not really what we usually think of as a relativistic, light cone, for wliidi we can point to interior points and definitely say they arc causally related and know for sure that points outside of each other s light cones are completely independent. In DM it is simply false to say that only those events inside the information cone of the past can influence a present event the information cone can well consist of lights cones stretching into all directions, forward and back in time.  [c.668]

In the same section, we also see that the source of the appropriate analytic behavior of the wave function is outside its defining equation (the Schibdinger equation), and is in general the consequence of either some very basic consideration or of the way that experiments are conducted. The analytic behavior in question can be in the frequency or in the time domain and leads in either case to a Kramers-Kronig type of reciprocal relations. We propose that behind these relations there may be an equation of restriction, but while in the former case (where the variable is the frequency) the equation of resh iction expresses causality (no effect before cause), for the latter case (when the variable is the time), the restriction is in several instances the basic requirement of lower boundedness of energies in (no-relativistic) spectra [39,40]. In a previous work, it has been shown that analyticity plays further roles in these reciprocal relations, in that it ensures that time causality is not violated in the conjugate relations and that (ordinary) gauge invariance is observed [40].  [c.97]

M. Floissart, in Dispersion Relations and their Connection with Causality, E. P. Wiguer, ed., Academie Press, New York, 1964, p, 1.  [c.173]

Dose—response relationships are useful for many purposes in particular, the following if a positive dose—response relationship exists, then this is good evidence that exposure to the material under test is causally related to the response the quantitative information obtained gives an indication of the spread of sensitivity of the population at risk, and hence influences ha2ard evaluation the data may allow assessments of no effects and minimum effects doses, and hence may be valuable in assessing ha2ard and by appropriate considerations of the dose—response data, it is possible to make quantitative comparisons and contrasts between materials or between species.  [c.232]

Declines in seal populations occurred in the Baltic Sea and the western-most part of the Wadden Sea (north of the Netherlands) between 1950 and 1975 numbers fell from more than 3000 to less than 500. This was accompanied by a sharp decline in pup production. Tissue levels of organochlorine compounds in female grey and ringed seals in the Baltic have been associated with reproductive problems, with higher levels of PCB and DDT metabolites being detected in the tissues of non-reprodiictive females than in the tissue of pregnant females. Associated damage to the endocrine, genital and urinary systems, adrenocortical hyperplasia, uterine stenoses and occlusions were also observed. Again it is not known whether or not these observations are causally linked.  [c.65]

S Greenland. Probability logic and probability induction. Epidemiology 9 322-332, 1998. GM Petersen, G Parmigiam, D Thomas. Missense mutations in disease genes A Bayesian approach to evaluate causality. Am J Hum Genet. 62 1516-1524, 1998.  [c.345]

Howard T. Odum (1971), an ecologist, is the most diligent in his attempts to reduce all-or nearly all-cultural phenomena to the currency of energy. On first examination his approach to causality is strikingly reminiscent of White. On closer examination, it seems that Odum holds a possibilistic position on causality, similar to that of Cottrell. In a section on theories of history, he comments apropos of the rise  [c.309]


See pages that mention the term Causality : [c.99]    [c.2]    [c.30]    [c.336]    [c.309]    [c.311]    [c.610]    [c.667]    [c.668]    [c.838]   
See chapters in:

Cellular automata  -> Causality