Luminescence measurements of hyperthermal Xe + O and O + Xe collision systems.

Emission excitation cross sections are recorded for collisions between Xe + O and O + Xe over a collision energy range of approximately 2 to 900 eV in the center-of-mass (E) frame. Emissive products of the O + Xe reaction are examined in the 700-1000 nm optical range and include neutral atomic oxygen emissions and neutral xenon emissions. Atomic emission products of the O + Xe collision appear to have measureable cross sections near E = 14 eV and increase in intensity until about E = 60 eV where they remain approximately constant for the remainder of the measured collision energies.

Providing technical assistance to ministries of health: lessons learned over 30 years.

Pursuing true country ownership for effective programs requires a long-term approach involving persistence, patience, keen understanding of counterparts' perspective, deference, building trust, focus on priorities, technical competence, and sustained optimism.

Shortening of RNA:DNA hybrid in the elongation complex of RNA polymerase is a prerequisite for transcription termination.

Passage of E. coli RNA polymerase through an intrinsic transcription terminator, which encodes an RNA hairpin followed by a stretch of uridine residues, results in quick dissociation of the elongation complex. We show that folding of the hairpin disrupts the three upstream base pairs of the 8 bp RNA:DNA hybrid, a major stability determinant in the complex.