Econometric Measurement of Earth\u27s Transient Climate Sensitivity

How sensitive is Earth’s climate to a given increase in atmospheric greenhouse gas (GHG) concentrations? This long-standing and fundamental question in climate science was recently analyzed by dynamic panel data methods using extensive spatiotemporal data of global surface temperatures, solar radiation, and GHG concentrations over the last half century to 2010 (Storelvmo et al, 2016). These methods revealed that atmospheric aerosol effects masked approximately one-third of the continental warming due to increasing GHG concentrations over this period, thereby implying greater climate sensitivity to GHGs than previously thought. The present study provides asymptotic theory justifying the use of these methods when there are stochastic process trends in both the global forcing variables, such as GHGs, and station-level trend effects from such sources as local aerosol pollutants. These asymptotics validate con dence interval construction for econometric measures of Earth’s transient climate sensitivity. The methods are applied to observational data and to data generated from three leading global climate models (GCMs) that are sampled spatio-temporally in the same way as the empirical observations. The fi ndings indicate that estimates of transient climate sensitivity produced by these GCMs lie within empirically determined con dence limits but that the GCMs uniformly underestimate the effects of aerosol induced dimming. The analysis shows the potential of econometric methods to calibrate GCM performance against observational data and to reveal the respective sensitivity parameters (GHG and non-GHG related) governing GCM temperature trends

Error in Airspeed Measurement Due to Static-Pressure Field Ahead of the Wing Tip of a Swept-Wing Airplane Model at Transonic Speeds

As part of a study of means of airspeed measurement at transonic speeds the use of static orifices located ahead of the wing tip has been investigated for possible application to service or research airspeed installations. The local static pressure and local Mach number have been measured at a distance of 1 tip chord ahead of the wing tip of a model of a swept-wing fighter airplane at true Mach numbers between 0.7 and 1.08 by the NACA wing-flow method. All measurements were made at or near zero lift. The local Mach number was found to be essentially equal to the true Mach numbers less than about 0.90. The local Mach number was found to be about 0.97 at a true Mach number of 0.95, and to be about 1.04 at a true Mach number of 1.08. The local Mach number provided a reasonable sensitive measure of true Mach number except for a restricted region near a true Mach number of 1.0 where the local Mach number did not change appreciably with true Mach number. The linear theory was found to predict qualitatively the effect of the fuselage on the static pressure ahead of the wing time but gave a reasonable prediction of the effect of the wing on the static pressure only at Mach numbers below 0.95

Allostery without conformation change: modelling protein dynamics at multiple scales

The original ideas of Cooper and Dryden, that allosteric signalling can be induced between distant binding sites on proteins without any change in mean structural conformation, has proved to be a remarkably prescient insight into the rich structure of protein dynamics. It represents an alternative to the celebrated Monod–Wyman–Changeux mechanism and proposes that modulation of the amplitude of thermal fluctuations around a mean structure, rather than shifts in the structure itself, give rise to allostery in ligand binding. In a complementary approach to experiments on real proteins, here we take a theoretical route to identify the necessary structural components of this mechanism. By reviewing and extending an approach that moves from very coarse-grained to more detailed models, we show that, a fundamental requirement for a body supporting fluctuation-induced allostery is a strongly inhomogeneous elastic modulus. This requirement is reflected in many real proteins, where a good approximation of the elastic structure maps strongly coherent domains onto rigid blocks connected by more flexible interface regions

Heat transfer measurement in aluminium oxide nanofluid using rectangular Thermosyphon loop

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Nanofluids are generally found to exhibit better thermophysical properties and heat transfer capabilities than the corresponding base fluids. Experimental and theoretical investigations on the forced and free convection behavior have reported superior heat transfer capability of nanofluids, except in a few cases. Studies on natural/free convective heat transfer in nanofluids have shown negative impacts when investigations were performed on a vertical column of the fluid. The absence of a pumping system makes natural circulation loops silent and also saves the energy for pumping the fluid. Since the thermosyphon loop resembles a forced circulation loop except for the absence of a pump, a nanofluid can be expected to yield enhanced heat transfer, compared to the base fluid. The present work captures the heat transfer performance of oxide nanofluids in a rectangular thermosyphon loop. The density gradient created by the temperature gradient between the heating and cooling sections, assisted by gravity, constitute the driving force in the loop. The temperature of the fluid at the inlet and exit of the heating sections and, on the pipe surface along the heating section is measured. The effect of the external heat input, concentration of nanofluids and average temperature of the cooling section on the heat transfer are investigated. The results have shown that the Al2O3 nanofluids have enhanced heat transfer characteristics as compared to water in rectangular thermosyphon loops.dc201

Morphology, phenology and agronomic traits of two wild Mexican common bean (Phaseolus vulgaris L.) populations under cultivation

The objective of this research was to characterise two populations of wild bean grown simultaneously in an experimental field site in Chapingo, Mexico. For comparative purposes, two cultivars of common bean were included. Only seven of 24 phenological and morphological traits (e.g. number of days to emergence, expansion of primary leaves and third trifoliolate leaf, number of branches per plant, diameter of stem, number of flower buds per plant and nodes per branch) investigated were statistically similar between and within wild samples due largely to differences in growth habit. The number of inflorescences, leaves, pods and seeds per wild plant fluctuated between 72 and 145, 109 and 206, 68 and 284 and 180 and 513, respectively. In contrast, each cultivar was highly homogeneous. Principal component analyses supported the conclusion that these morphological and agronomic characteristics of wild common bean populations primarily depend on the predominant growth habit type and that under different environments, the expression of these traits may change

Temperature dependence of the ``0.7'' 2(e^2)/h quasi plateau in strongly confined quantum point contacts

We present new results of the ``0.7'' 2(e^2)/h structure or quasi plateau in some of the most strongly confined point contacts so far reported. This strong confinement is obtained by a combination of shallow etching and metal gate deposition on modulation doped GaAs/GaAlAs heterostructures. The resulting subband separations are up to 20 meV, and as a consequence the quantized conductance can be followed at temperatures up to 30 K, an order of magnitude higher than in conventional split gate devices. We observe pronounced quasi plateaus at several of the lowest conductance steps all the way from their formation around 1 K to 30 K, where the entire conductance quantization is smeared out thermally. We study the deviation of the conductance from ideal integer quantization as a function of temperature, and we find an activated behavior, exp(-T_a/T), with a density dependent activation temperature T_a of the order of 2 K. We analyze our results in terms of a simple theoretical model involving scattering against plasmons in the constriction.Comment: RevTex (4 pages) including 2 postscript figures. To appear in Physica B, 199

Production of Ξ−\Xi^--hypernuclei via the (K−,K+K^-,K^+) reaction in a quark-meson coupling model

We study the production of $\Xi^-$-hypernuclei, $^{12}_{\Xi^{-}}$Be and $^{28}_{\Xi^{-}}$Mg, via the ($K^-,K^+$) reaction within a covariant effective Lagrangian model, employing the bound $\Xi^-$ and proton spinors calculated by the latest quark-meson coupling model. The present treatment yields the $0^\circ$ differential cross sections for the formation of simple s-state $\Xi^-$ particle-hole states peak at a beam momentum around 1.0 GeV/c with a value in excess of 1 $\mu$b.Comment: Accepted version with miner changes, 4 pages, 2 figures, Presented at the 20th International IUPAP Conference on Few-Body Problems in Physics, 20 - 25 August, 2012, Fukuoka, Japa

Fiber optic sensing of magnetic fields utilizing femtosecond laser sculpted microslots and long period gratings coated with Terfenol-D

Fiber optic sensors are fabricated for detecting static magnetic fields. The sensors consist of a UV inscribed long period grating with two 50 micron long microslots. The microslots are fabricated using the femtosecond laser based inscribe and etch technique. The microslots and the fiber surface are coated with a magnetostrictive material Terfenol-D. A spectral sensitivity of 1.15 pm/mT was measured in transmission with a working resolution of ±0.2 mT for a static magnetic field strength below 10 mT. These devices also present a different response when the spatial orientation of the fiber was adjusted relative to the magnetic field lines