2,686 research outputs found
How does the Introduction of an ETF Market with Liquidity Providers Impact the Liquidity of the Underlying Stocks?.
This article examines how the inception of an ETF market impacts several dimensions of the liquidity of the ETF-underlying-index stocks. In contrast with previous research, our evidence is based on an ETF market where liquidity providers (LPs) act as market makers. We find that: (1) the market for the underlying stocks becomes more liquid after the ETF ntroduction for investors who trade at the best-limit quotes; (2) but the stock market becomes ess deep for larger traders, most probably because some large liquidity traders exit the underlying stocks’ market for the ETF market. Some statistics suggest that those results could be related to the trading activity of ETF LPs.Transaction Costs; Exchange-Traded Fund (ETF); Index Trading;
Nonlinear modal testing performed by pulsed-air jet excitation system
This paper presents a novel approach for testing structural component to nonlinear vibrations. Nowadays, nonlinear testing is mainly carried out by using electromagnetic shakers. These are efficient and powerful excitation systems which transmit the force by a rigid stinger and can be driven by different excitation signals. The rigid connection contributes to create mechanical impedance mismatch between the shaker and the test structure thus reducing the efficiency of the driving force. An alternative solution to shakers is represented by use of a pulsed air jet excitation method, which drives the force by a pulsed air-jets and therefore contactless. This condition eliminates the mechanical impedance mismatch with the test structure and the excitation can be more efficient than the one created by shakers. The pulsed air-jet excitation system is used to study nonlinear vibrations of composites components. These were designed to be mock-ups of fan blades the layup of which was varied for the three types of components used in this work. Tests were carried out by performing forced response and free decay measurements. The free decay type of test revealed interesting results and the novelty of using such an exciter for nonlinear testing. The major novelty consists of interrupting the air flow from a steady state condition and let happen the free decay, all these without experiencing undesired dynamics as experienced by contact excitatio
The evolution of a revolution: re-designing green revolution breeding programs in Asia and Africa to increase rates of genetic gain. [W020]
As rice feeds nearly half of the human population, rice breeding is a critical focal point for achieving the UN Sustainable Development Goal of eliminating hunger and poverty by 2030 and to providing a sufficient quantity of safe and nutritious food to vulnerable populations in the developing world. However, despite dramatic improvements in understanding the genetic basis of complex traits in rice over the last 20 years, annual rates of genetic gain for yield and other important traits in most public rice breeding programs in Asia and Africa are extremely low. Understanding and manipulating the key drivers of genetic gain will be necessary for rice breeding programs to fully meet the expectations of the 21st century. Funded by the Bill and Melinda Gates foundation and in coordination with the CGIAR Excellence in Breeding Platform, the International Rice Research Institute (IRRI) aims to transform rice breeding by aligning IRRI's international breeding efforts together with national public breeding programs (NARs programs) into collaborative regional breeding networks. These CGIAR-NARs breeding networks serve as a platform to deploy an integrated breeding model that combines modern genomic technologies with regional knowledge and testing capabilities to ensure that smallholder rice farmers have access to a steady stream of consistently improved, high yielding, locally adapted, and market-ready rice varieties
Thermodiffusion phenomena.
The aim of this article is to present briefly a summary of the state of art in theoretical, experimental and numerical approaches in thermodiffusion. The concepts and equations giving the mass flux of constituents in binary, ternary and multicomponent mixtures are presented
Thermodynamic analysis of inverted bifurcation
We present a thermodynamic analysis of inverted bifurcation
in binary mixtures heated from below. From this analysis it
follows that an inverted bifurcation is caused by the competition
between a stabilizing effect with a long relaxation time and a
destabilizing effect with a short relaxation time. These
conditions are precisely the same as those that give rise to
overstability. This might explain why overstability and inverted
bifurcation occur in the same systems
Traveling Wave Fronts and Localized Traveling Wave Convection in Binary Fluid Mixtures
Nonlinear fronts between spatially extended traveling wave convection (TW)
and quiescent fluid and spatially localized traveling waves (LTWs) are
investigated in quantitative detail in the bistable regime of binary fluid
mixtures heated from below. A finite-difference method is used to solve the
full hydrodynamic field equations in a vertical cross section of the layer
perpendicular to the convection roll axes. Results are presented for
ethanol-water parameters with several strongly negative separation ratios where
TW solutions bifurcate subcritically. Fronts and LTWs are compared with each
other and similarities and differences are elucidated. Phase propagation out of
the quiescent fluid into the convective structure entails a unique selection of
the latter while fronts and interfaces where the phase moves into the quiescent
state behave differently. Interpretations of various experimental observations
are suggested.Comment: 46 pages, 11 figures. Accepted for publication in Phys. Rev.
Convection in nanofluids with a particle-concentration-dependent thermal conductivity
Thermal convection in nanofluids is investigated by means of a continuum
model for binary-fluid mixtures, with a thermal conductivity depending on the
local concentration of colloidal particles. The applied temperature difference
between the upper and the lower boundary leads via the Soret effect to a
variation of the colloid concentration and therefore to a spatially varying
heat conductivity. An increasing difference between the heat conductivity of
the mixture near the colder and the warmer boundary results in a shift of the
onset of convection to higher values of the Rayleigh number for positive values
of the separation ratio psi>0 and to smaller values in the range psi<0. Beyond
some critical difference of the thermal conductivity between the two
boundaries, we find an oscillatory onset of convection not only for psi<0, but
also within a finite range of psi>0. This range can be extended by increasing
the difference in the thermal conductivity and it is bounded by two
codimension-2 bifurcations.Comment: 13 pages, 11 figures; submitted to Physical Review
Best friends: children use mutual gaze to identify friendships in others
This study examined children’s ability to use mutual eye gaze as a cue to friendships in others. In Experiment 1, following a discussion about friendship, 4-, 5-, and 6-year-olds were shown animations in which three cartoon children looked at one another, and were told that one target character had a best friend. Although all age groups accurately detected the mutual gaze between the target and another character, only 5- and 6-year-olds used this cue to infer friendship. Experiment 2 replicated the effect with 5- and 6-year-olds when the target character was not explicitly identified. Finally, in Experiment 3, where the attribution of friendship could only be based on synchronized mutual gaze, 6-year-olds made this attribution, while 4- and 5-year-olds did not. Children occasionally referred to mutual eye gaze when asked to justify their responses in Experiments 2 and 3, but it was only by the age of 6 that reference to these cues correlated with the use of mutual gaze in judgements of affiliation. Although younger children detected mutual gaze, it was not until 6 years of age that children reliably detected and justified mutual gaze as a cue to friendship
Influence of through-flow on linear pattern formation properties in binary mixture convection
We investigate how a horizontal plane Poiseuille shear flow changes linear
convection properties in binary fluid layers heated from below. The full linear
field equations are solved with a shooting method for realistic top and bottom
boundary conditions. Through-flow induced changes of the bifurcation thresholds
(stability boundaries) for different types of convective solutions are deter-
mined in the control parameter space spanned by Rayleigh number, Soret coupling
(positive as well as negative), and through-flow Reynolds number. We elucidate
the through-flow induced lifting of the Hopf symmetry degeneracy of left and
right traveling waves in mixtures with negative Soret coupling. Finally we
determine with a saddle point analysis of the complex dispersion relation of
the field equations over the complex wave number plane the borders between
absolute and convective instabilities for different types of perturbations in
comparison with the appropriate Ginzburg-Landau amplitude equation
approximation. PACS:47.20.-k,47.20.Bp, 47.15.-x,47.54.+rComment: 19 pages, 15 Postscript figure
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