|In the course of 30 years since the discovery of HIV as the causative agent of AIDS we have made remarkable progress in understanding the biology and pathogenesis of the virus and the field of viral dynamics has been critical for understanding the details of progression of HIV infection to AIDS. A typical primary infection is characterized by high levels of viral titers in plasma with concomitant decrease in the CD4+ T cell numbers. At the end of primary infection stage the viral titers decline due to depletion of CD4+ T cells and partial immune activation. Few months later the virus enters the chronic stage typified by a slow increase in the viral titers and gradual decrease in the CD4+ T cell levels, immune activation, increased cell turnover and destruction of host immune system.
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.