Rare dental trait provides morphological evidence of archaic introgression in Asian fossil record

The recently described Denisovan hemimandible from Xiahe, China [F. Chen et al., (2019) Nature 569, 409–412], possesses an unusual dental feature: a 3-rooted lower second molar. A survey of the clinical and bioarchaeological literature demonstrates that the 3-rooted lower molar is rare (less than 3.5% occurrence) in non-Asian Homo sapiens. In contrast, its presence in Asian-derived populations can exceed 40% in China and the New World. It has long been thought that the prevalence of 3-rooted lower molars in Asia is a relatively late acquisition occurring well after the origin and dispersal of H. sapiens. However, the presence of a 3-rooted lower second molar in this 160,000-y-old fossil hominin suggests greater antiquity for the trait. Importantly, it also provides morphological evidence of a strong link between archaic and recent Asian H. sapiens populations. This link provides compelling evidence that modern Asian lineages acquired the 3-rooted lower molar via introgression from Denisovans

Unimodular cosmology and the weight of energy

Some models are presented in which the strength of the gravitational coupling of the potential energy relative to the same coupling for the kinetic energy is, in a precise sense, adjustable. The gauge symmetry of these models consists of those coordinate changes with unit jacobian.Comment: LaTeX, 23 pages, conclusions expanded. Two paragraphs and a new reference adde

Experimental and predicted vapour-liquid equilibrium of the binary mixtures n-heptane + chlorobutane isomers

The study of the isothermal vapour-liquid equilibrium (VLE) of the binary mixtures n-heptane plus chlorobutane isomers (1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane or 2-chloro-2-methylpropane) at three different temperatures, T = 288.15, 298.15 and 308.15 K, is presented in this contribution. The experimental results were correlated using Wilson equation and the thermodynamic consistency of the data was checked by the van Ness method. Furthermore, two different methods have been used to predict the phase equilibrium in isothermal conditions: a pure group contribution method (modified-UNIFAC) and a group contribution equation of state (VTPR)

Operation speed of polariton condensate switches gated by excitons

We present a time-resolved photoluminescence (PL) study in real- and momentum-space of a polariton condensate switch in a quasi-1D semiconductor microcavity. The polariton flow across the ridge is gated by excitons inducing a barrier potential due to repulsive interactions. A study of the device operation dependence on the power of the pulsed gate beam obtains a satisfactory compromise for the ON/OFF-signal ratio and -switching time of the order of 0.3 and $\thicksim50$ ps, respectively. The opposite transition is governed by the long-lived gate excitons, consequently the OFF/ON-switching time is $\thicksim200$ ps, limiting the overall operation speed of the device to $\thicksim3$ GHz. The experimental results are compared to numerical simulations based on a generalized Gross-Pitaevskii equation, taking into account incoherent pumping, decay and energy relaxation within the condensate.Comment: 11 pages, 11 figure

Optical control of spin textures in quasi-one-dimensional polariton condensates

We investigate, through polarization-resolved spectroscopy, the spin transport by propagating polariton condensates in a quasi one-dimensional microcavity ridge along macroscopic distances. Under circularly polarized, continuous-wave, non-resonant excitation, a sinusoidal precession of the spin in real space is observed, whose phase depends on the emission energy. The experiments are compared with simulations of the spinor-polariton condensate dynamics based on a generalized Gross-Pitaevskii equation, modified to account for incoherent pumping, decay and energy relaxation within the condensate.Comment: 10 pages, 9 figure

Energy relaxation of exciton-polariton condensates in quasi-1D microcavities

We present a time-resolved study of energy relaxation and trapping dynamics of polariton condensates in a semiconductor microcavity ridge. The combination of two non-resonant, pulsed laser sources in a GaAs ridge-shaped microcavity gives rise to profuse quantum phenomena where the repulsive potentials created by the lasers allow the modulation and control of the polariton flow. We analyze in detail the dependence of the dynamics on the power of both lasers and determine the optimum conditions for realizing an all-optical polariton condensate transistor switch. The experimental results are interpreted in the light of simulations based on a generalized Gross-Pitaevskii equation, including incoherent pumping, decay and energy relaxation within the condensate.Comment: 15 pages, 20 figure

The Key Elements and Drivers of the Defense Acquisition System

Excerpt from the Proceedings of the Nineteenth Annual Acquisition Research SymposiumA systemic diagram (systemigram) was developed to provide a systems view of the key elements and drivers of the complex defense acquisition system in the United States. An iterative process was used to develop the systemigram, after assessing the basic relationships among key actors and organizations within the system. The diagram provides a high-level overview of the Department of Defense ecosystem as it relates to acquisition, addressing the lack of available high-level visual representations of the overall acquisition system elements and their basic interactions within the literature. Using this diagram, individuals unfamiliar with the defense acquisition system can become better acquainted with it, while those familiar with defense acquisition are provided with a useful artifact to stimulate shared understanding, spark conversations about how to improve acquisition outcomes, and focus on the key inputs, processes, and ultimate goal of military capability.Approved for public release; distribution is unlimited

The Key Elements and Drivers of the Defense Acquisition System

Symposium PresentationApproved for public release; distribution is unlimited