KURVS: The outer rotation curve shapes and dark matter fractions of z∼1.5z \sim 1.5 star-forming galaxies

We present first results from the KMOS Ultra-deep Rotation Velocity Survey (KURVS), aimed at studying the outer rotation curves shape and dark matter content of 22 star-forming galaxies at $z\sim1.5$. These galaxies represent `typical' star-forming discs at $z \sim 1.5$, being located within the star-forming main sequence and stellar mass-size relation with stellar masses $9.5\leqslant$log$(M_{\star}/\mathrm{M_{\odot}})\leqslant11.5$. We extract individual rotation curves out to 4 times the effective radius, on average, or $\sim 10-15$ kpc. Most rotation curves are flat or rising between three- and six-disc scale radii. Only three objects with dispersion-dominated dynamics ($v_{\rm rot}/\sigma_0\sim0.2$) have declining outer rotation curves at more than 5$\sigma$ significance. After accounting for seeing and pressure support, the nine rotation-dominated discs with $v_{\rm rot}/\sigma_0\geqslant1.5$ have average dark matter fractions of $50 \pm 20\%$ at the effective radius, similar to local discs. Together with previous observations of star-forming galaxies at cosmic noon, our measurements suggest a trend of declining dark matter fraction with increasing stellar mass and stellar mass surface density at the effective radius. Simulated EAGLE galaxies are in quantitative agreement with observations up to log$(M_{\star}R_{\rm eff}^{-2}/\mathrm{M_{\odot}kpc^{-2}}) \sim 9.2$, and over-predict the dark matter fraction of galaxies with higher mass surface densities by a factor of $\sim 3$. We conclude that the dynamics of typical rotationally-supported discs at $z \sim 1.5$ is dominated by dark matter from effective radius scales, in broad agreement with cosmological models. The tension with observations at high stellar mass surface density suggests that the prescriptions for baryonic processes occurring in the most massive galaxies (such as bulge growth and quenching) need to be reassessed.Comment: 23 pages, 9 figures. Resubmitted to MNRAS after addressing the referee's comments. Abstract slightly modified to compile with the arXiv formattin

Resistance, Redistribution and Investor-Friendliness

Poor communities sometimes resist private investment and destroy economic surplus even if the government has the willingness and ability to redistribute. We interpret such acts of resistance as demands for redistribution: Destruction contains credible information about how affected groups value surplus, which helps the government in implementing the optimal redistribution policy. Destruction is increasing in the extent of political marginalization of the affected group. While resistance has informational value, it has two distinct costs: it directly reduces surplus and also reduces the investor’s incentives to create surplus. The government uses a tax/subsidy on the investor to maximize weighted social surplus, and we show that the possibility of destruction may force the government to be too soft in its negotiations with the investor. We discuss conditions under which the government should ban resistance or should allow resistance but compensate the investor for its losses incurred in order to enhance social welfare

Augmented Reality for Railroad Operations Using Head-up Displays

693JJ6-18-C-000010A team from MIT\u2019s Human Systems Laboratory designed the locomotive HUD as a wide field of view augmented reality head-up display (AR-HUD). The technical feasibility of an AR-HUD was assessed through literature review and hardware tests. To study human factors issues, an AR-HUD prototype was designed, reviewed by experienced engineers, then implemented in the FRA Cab Technology Integration Laboratory simulator. The engineers\u2019 behavior was not significantly altered and using the AR-HUD reduced the time spent looking away from the forward view. Subjective feedback from the engineers confirmed the acceptability and potential benefit of using HUDs

Evidence for changes in stratospheric transport and mixing over the past three decades based on multiple data sets and tropical leaky pipe analysis

Variability in the strength of the stratospheric Lagrangian mean meridional or Brewer-Dobson circulation and horizontal mixing into the tropics over the past three decades are examined using observations of stratospheric mean age of air and ozone. We use a simple representation of the stratosphere, the tropical leaky pipe (TLP) model, guided by mean meridional circulation and horizontal mixing changes in several reanalyses data sets and chemistry climate model (CCM) simulations, to help elucidate reasons for the observed changes in stratospheric mean age and ozone. We find that the TLP model is able to accurately simulate multiyear variability in ozone following recent major volcanic eruptions and the early 2000s sea surface temperature changes, as well as the lasting impact on mean age of relatively short-term circulation perturbations. We also find that the best quantitative agreement with the observed mean age and ozone trends over the past three decades is found assuming a small strengthening of the mean circulation in the lower stratosphere, a moderate weakening of the mean circulation in the middle and upper stratosphere, and a moderate increase in the horizontal mixing into the tropics. The mean age trends are strongly sensitive to trends in the horizontal mixing into the tropics, and the uncertainty in the mixing trends causes uncertainty in the mean circulation trends. Comparisons of the mean circulation and mixing changes suggested by the measurements with those from a recent suite of CCM runs reveal significant differences that may have important implications on the accurate simulation of future stratospheric climate

Al Tahlil Al Idari Fi Al Munazhamat Al Ammat : Tarikhihi, Mafahimihi, Asalibihi

229 hal.; 24 c

Adoption of grading practices according to ISO 16624:2018 for Bambusa blumeana in the Philippines: a case study

ISO 19624:2018 is the world’s first international bamboo grading standard. It contains few prescriptive clauses and is mostly written as a recipe for a national grading standard. This paper reports the initial phases of the implementation of this standard in the context of a production plant (Kawayan Collective) exploiting Bambusa blumeana harvested in The Philippines. The team undertook the initial evaluation (i.e. characterization) of B. blumeana harvested from six sites. 123 culms were geometrically and mechanically characterised, as required by ISO 19624. Current visual grading rules used at Kawayan Collective have been recorded as well as their associated rejection rates and resulting associated cost of this rejection. Early findings from the initial evaluation are discussed