Relationships causal

There should be sufficient dose—response information to allow decisions on causal relationships and relevance. 

The results of the study should allow decisions on whether injury is a direct result of toxicity or secondary to other events. In addition to confirming a causal relationship between exposure to the test material and development of an injury, the study should be reviewed in order to assess whether information is available to determine if the effect is traceable to parent material or metaboUte. 

Relationships Between Objects, Processes, and Events. Relationships can be causal, eg, if there is water in the reactor feed, then an explosion can take place. Relationships can also be stmctural, eg, a distiUation tower is a vessel containing trays that have sieves in them or relationships can be taxonomic, eg, a boiler is a type of heat exchanger. Knowledge in the form of relationships connects facts and descriptions that are already represented in some way in a system. Relational knowledge is also subject to uncertainty, especiaUy in the case of causal relationships. The representation scheme has to be able to express this uncertainty in some way. 

Evidence for chemically mediated disruption of thyroid function in wild reptile populations includes the finding of elevated thyroxine levels in male alligators from Lake Apopka, although a causal relationship with specific chemicals has not been established. ... 

In the future, the preventive tole of toxicology will be emphasized. It will be increasingly important to develop early indicators to monitor longterm subtle exposures that predict deleterious effects that are known to have a causal relationship with occupational exposures. In addition to collection of blood and urine samples, also collection of cells from points of... 

Atmospheric exposure trials, carried out in Cambridge, established the fact that when rusty specimens were painted in the summer, their condition, after some years exposure, was very much better than that of similar specimens painted in the winter It was found that steel weathered in Cambridge carried spots of ferrous sulphate, deeply imbedded in the rust, and that the quantity of ferrous sulphate/unit area was very much greater in the winter than in the summer this seasonal variation was attributed to the increased sulphur dioxide pollution of the atmosphere in the winter, caused by the combustion of coal in open grates. It was concluded that there was a causal relationship between the quantity of ferrous sulphate and the effective life of the paint. It was suggested that these soluble deposits of ferrous sulphate short-circuit the resistance of the paint film and, since paint films are very permeable to water and oxygen, the ferrous sulphate will become oxidised and hydrolysed with the production of voluminous rust, which will rupture the film at numerous points, thus giving rise to the characteristic type of failure seen on painted rusty surfaces. 

For future research in this field, in addition to physiological and biochemical approaches, genetic analysis will be essential in the establishment of causal relationships between the induction of a stress protein and the establishment of tolerance to the stress condition. In most cases it is not difficult to detect the induction of new proteins during stress. However, the induction of new proteins does not necessarily establish stress tolerance it may well be the consequence of damage caused by stress conditions. Thus, genetic mutants will be necessary to test the physiological role of a stress protein. 

Galassi G, Gentilini M et al (1998) Motor neuron disease and HIV-1 infection in a 30-year-old HIV-positive heroin abuser a causal relationship Clin Neuropathol 17(3) 131-135 Gherardi R, Lebargy F et al (1989) Necrotizing vasculitis and HIV replication in peripheral nerves. N Engl J Med 321(10) 685-686... 

Causal relationship Because of the impossibility of isolating factors Avithin a system and its context, it is difficult to draw a rigorous causal relationship between one factor and another. It is therefore not possible to conclude that a particular factor will always lead to the same result in a different country. 

In inverse calibration one models the properties of interest as a function of the predictors, e.g. analyte concentrations as a function of the spectrum. This reverses the causal relationship between spectrum and chemical composition and it is geared towards the future goal of estimating the concentrations from newly measured spectra. Thus, we write... 

Molecular analysis of the interaction between plants, microbes, and soil components may help us understand the causal relationships of events taking plaee in the rhizosphere. Nevertheless, due to the necessity to simplify the experimental approaches, we still do not have the complete picture that takes into ae-count the relative weight of each factor. 

We realize that the information in the book is still largely descriptive and that the interdisciplinary view of the causal relationships in the rhizosphere is still in its infancy. Nevertheless, we do hope that our efforts and the high-quality scientific contributions will stimulate further interest in and work on this fascinating topic. 

These results clearly demonstrate that PCP-like drugs administered centrally produce stereotyped behavior that is mediated by PCP receptors. A causal relationship between binding to PCP receptors and induction of stereotyped behavior is also supported by the ability of metaphit, which specifically acylates PCP receptors in vivo, to antagonize induction of stereotyped behavior. The order of drug potency of PCP analogs and dexoxadrol to induce stereotyped behavior is similar to that seen in other studies on the binding of 3H-PCP (Hampton et al. 1982 Murray and Leid 1984) and... 

Until the discovery of HP, psychological stress was considered one of the primary causes of PUD. Although psychosocial factors such as life stress, baseline personality patterns, and depression may influence PUD prevalence, a clear causal relationship has not been demonstrated. 

The role of antigens derived from dietary intake in the development of IBD is less well defined. There is some speculation that ingestion of large quantities of refined carbohydrates or margarine leads to higher rates of CD. Use of oral contraceptives has been associated with increased development of IBD in some cohort studies, but a strong causal relationship has not been proven.7... 

Over 20 infectious agents have been incriminated as etiologic agents for many the causal relationship has been disproved, and for others there is conflicting evidence. Human herpesvirus 6 (HHV-6) is currently the most likely causative virus. HHV-6 may initiate the autoimmune processes of MS in one of two ways. First, HHV-6 is structurally similar to myelin basic protein. When T cells become sensitive to HHV-6, the cells may attack myelin basic protein. Second, HHV-6 may directly stimulate the complement cascade, activating autoimmune processes.5 Infection with HHV-6 alone cannot fully explain MS, because HHV-6 is found in 75% of all people, but MS is much more rare. 

The risk of gout increases as the serum uric acid concentration increases, and approximately 30% of patients with levels greater than 10 mg/dL (greater than 595 pmol/L) develop symptoms of gout within 5 years. However, most patients with hyperuricemia are asymptomatic. Other risk factors for gout include obesity, ethanol use, and dyslipidemia. Gout is seen frequently in patients with type 2 diabetes mellitus and coronary artery disease, but a causal relationship has not been established. 

Berkowitz RD, Alexander S, McCune JM. Causal relationships between HIV-1 coreceptor utilization, tropism, and pathogenesis in human thymus. AIDS Res Hum Retroviruses 2000 16 1039-1045. 

Any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. 

Ideally, to establish a causal relationship between caffeine and improved athletic performance, evidence would be obtained from epidemiological population studies, followed by careful, double-blind, placebo controlled experimental protocols isolating the purported etiological agent (caffeine), and eventually culminating with strong laboratory findings... 

In addition to the classical stress hormones already reviewed, several other hormones are augmented in response to stress. Stress-induced prolactin release is one of the most frequently studied examples. There is no doubt about the causal relationship between stress and increased pituitary prolactin release, but the biological meaning is much less clear (G2). This phylogenetically old hormone has been shown to have more than 85 different functions in all vertebrate species. However, besides its role in the induction of maternal lactogenesis, the physiological importance of prolactin is at present not fully established. Experimental and clinical evidence supports the view that prolactin is also an immunoregulating hormone (M44, R18). Prolactin receptors are present on human T and B lymphocytes (R18), and T lymphocytes depend on prolactin for maintenance of immunocompetence (B19). In addition, it has been shown that prolactin is able to influence the devel-... 

After Laplace transform, a differential equation of deviation variables can be thought of as an input-output model with transfer functions. The causal relationship of changes can be represented by block diagrams. 

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