37 research outputs found
Home birth without skilled attendants despite millennium villages project intervention in Ghana: insight from a survey of women’s perceptions of skilled obstetric care
Lawson criterion for ignition exceeded in an inertial fusion experiment
For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37Â MJ of fusion for 1.92Â MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion
Serotonin acts as a radical scavenger and is oxidized to a dimer during the respiratory burst of human mononuclear and polymorphonuclear phagocytes
Laser spectroscopic characterization of the nuclear-clock isomer Th
The isotope Th is the only nucleus known to possess an excited state
Th in the energy range of a few electron volts, a transition energy
typical for electrons in the valence shell of atoms, but about four orders of
magnitude lower than common nuclear excitation energies. A number of
applications of this unique nuclear system, which is accessible by optical
methods, have been proposed. Most promising among them appears a highly precise
nuclear clock that outperforms existing atomic timekeepers. Here we present the
laser spectroscopic investigation of the hyperfine structure of
Th, yielding values of fundamental nuclear properties, namely
the magnetic dipole and electric quadrupole moments as well as the nuclear
charge radius. After the recent direct detection of this long-searched-for
isomer, our results now provide detailed insight into its nuclear structure and
present a method for its non-destructive optical detection.Comment: 18 page