|The effect of environmental contaminants on health is a major concern because over the last two decades, several studies worldwide have shown how chemicals present in our environment can profoundly affect the etiology of some chronic diseases. Indeed, pesticides toxicity has been clearly demonstrated to alter neurological functions and numerous epidemiological studies have shown a relationship between pesticides exposure and the etiology of Parkinsons disease (PD). However, epidemiological results are inconclusive because there is considerable heterogeneity in results likely due to statistical analysis, methodological differences, study design, control selection, differences in exposure assessment methods and diagnosis of patients.
The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information.The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.