Kinetic discrimination in T-cell activation.

We propose a quantitative model for T-cell activation in which the rate of dissociation of ligand from T-cell receptors determines the agonist and antagonist properties of the ligand. The ligands are molecular complexes between antigenic peptides and proteins of the major histocompatibility complex on the surfaces of antigen-presenting cells. Binding of ligand to receptor triggers a series of biochemical reactions in the T cell. If the ligand dissociates after these reactions are complete, the T cell receives a positive activation signal. However, dissociation of ligand after completion of the first reaction but prior to generation of the final products results in partial T-cell activation, which acts to suppress a positive response. Such a negative signal is brought about by T-cell ligands containing the variants of antigenic peptides referred to as T-cell receptor antagonists. Results of recent experiments with altered peptide ligands compare favorably with T-cell responses predicted by this model.

Attitudes towards disability in education through the SSCI (2000-2011): a topical and bibliometric analysis

Introduction. The purpose of this study is to describe and characterize the international sci-entific output relating to “attitudes towards disability in education”, using a battery of bibliometric indicators that make it possible to analyze and monitor international scientific activity. Method. This ex post facto retrospective study analyzed 925 papers published in the Social Sciences Citation Index (SSCI) database during the period 2000-2011. Results. The number of publications increased steadily between 2006 and 2010. The results reported here include the most productive authors, the journals that deal with this topic, and the articles cited most often. An analysis of research types showed a tendency toward empiri-cal studies. A total of 18 categories were identified when considering article content, and the distribution of the research studies across stages of education was found to be uneven. Discussion and Conclusion. The results reveal a topic that is highly current in today’s scien-tific community, and offer us a view of the traits that have characterized research on "attitudes towards disability in education" for the last eleven years.