20 research outputs found
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
Arching the back (lumbar curvature) as a female sexual proceptivity signal: an eye-tracking study
It is common in studies of human mate preference
to have participants judge the attractiveness of photographs in
which models adopt a neutral facial expression or a neutral
body posture. However, it is unlikely that humans adopt neutral
expressions and postures in normal social circumstances.
One way in which posture can vary is in the curvature of the
lower spine. In some non-human animals, a “lordotic” posture
(in which the lower spine is curved towards the belly) is associated
in females with readiness to mate. In humans, this
posture may serve a similar function, attracting heterosexual
men. In this study, participants were presented with computergenerated
images of female bodies in which the back curvature
was systematically manipulated. The result showed that
small changes in lumbar curvature are associated with changes
in the perception of attractiveness. Specifically, the result
showed that there is a relationship between the range of the
back curvatures used in this study and attractiveness, such that
increasing the curvature increased the perception of attractiveness.
Additionally, as the curvature increased, participants
looked longer and fixated more on the hip region of the female
bodies. This paper argues that the attractiveness of women in
lordotic posture is due to a conserved mechanism across the
taxa which signals proceptivity to men.This study was supported by the Portuguese Foundation for Science and Technology and the Portuguese Ministry of Science, Technology and Higher Education through national funds and co-financed by FEDER through COMPETE2020 under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007653). FP receives funding from FCT Portugal through grant SFRH/BD/114366/2016; AM receives funding from FCT Portugal through grants PTDC/DTP-EPI/0412/2012 and PEST-C/FIS/UI607/2011; JA receives funding from FCT Portugal through grant IF/01298/2014.info:eu-repo/semantics/publishedVersio