How safe are the world’s roads?

How safe are the world's roads?

a Department of Violence and Injury Prevention and Disability, World Health Organization, 20 avenue Appia, 1211 Geneva 27, Switzerland. Correspondence to Tami Toroyan (e-mail: [email protected]). Road traffic injuries are a leading public health problem, resulting in over 1.2 million deaths each year.1 They affect all age groups but their impact is most striking among the young: they are the lea...

How Fictional Worlds Are Created

Both adults and children have the ability to not only think about reality but also use their imaginations and create fictional worlds. This article describes the process by which world creation happens, drawing from philosophical and psychological treatments of this issue. First, world creators recognize the need to create a fictional world, as when starting a pretend game or opening a novel. T...

Are we really in safe hands? How safe is safe?

How safe are intraocular lenses?

Hematopoietic (stem) cell development — how divergent are the roads taken?

The development of the hematopoietic system during early embryonic stages occurs in spatially and temporally distinct waves. Hematopoietic stem cells (HSC), the most potent and self-renewing cells of this system, are produced in the final 'definitive' wave of hematopoietic cell generation. In contrast to HSCs in the adult, which differentiate via intermediate progenitor populations to produce f...