2,900 research outputs found
Prices and volumes of options: A simple theory of risk sharing when markets are incomplete
We present a simple theory of business-cycle movements of option prices and volumes. This theory relies on time-varying heterogeneity between agents in their demand for insurance against aggregate risk. Formally, we build an infinite-horizon model where agents face an aggregate risk, but also different levels of idiosyncratic risk. We manage to characterize analytically a general equilibrium in which positive quantities of derivatives are traded. This allows us to explain the informational content of derivative volumes over the business cycle. We also carry out welfare analysis with respect to the introduction of options, which appears not to be Pareto-improving.Option Pricing, Open Interest, Incomplete Markets.
Incomplete markets, liquidation risk, and the term structure of interest rates
We analyze the term structure of real interest rates in a general equilibrium model with incomplete markets and borrowing constraints. Agents are subject to both aggregate and idiosyncratic income shocks, which latter may force them into early portfolio liquidation in a bad aggregate state. We derive a closed-form equilibrium with limited agent heterogeneity (despite market incompleteness), which allows us to produce analytical expressions for bond prices and returns at any maturity. The attractiveness of bonds as liquidity makes aggregate bond demand downward-sloping, so that greater bond supply raises both the level and the slope of the yield curve. Moreover, time-variations in liquidation risk are shown to help explain the rejection of the Expectations Hypothesis.Incomplete markets; yield curve; borrowing constraints.
Use of Ecogeographical Factors for Sampling a Core Collection of Perennial Ryegrass
In order to set up a core collection of wild populations of pei:ennial ryegra11 {Lolium perenne L.), 3 different criteria have been combined lo make a choice of populations: similarities between populations, geographic location and ecological characteristics of their original sites. Different multivariate analysis and clustering methods, introducing a geographic contiguity CXJnstnint were used to sample, among a set of 550 Prench wild populations, 114 populations 111 representative as po11ible of the whole variability
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Shear-Wave Splitting and Mantle Flow Beneath the Colorado Plateau and its Boundary with the Great Basin
Shear-wave splitting measurements from SKS and SKKS phases show fast polarization azimuths that are subparallel to North American absolute plate motion within the central Rio Grande Rift (RGR) and Colorado Plateau (CP) through to the western rim of the CP, with anisotropy beneath the CP and central RGR showing a remarkably consistent pattern with a mean fast azimuth of 4 degrees +/- degrees 6 E of N. Approaching the rim from the southeast, fast anisotropic directions become north-northeast-south-southwest (NNE-SSW), rotate counter clockwise to north-south in the CP-GB transition, and then to NNW-SSE in the western Great Basin ( GB). This change is coincident with uppermost mantle S-wave velocity perturbations that vary from +4% beneath the western CP and the eastern edge of the Marysvale volcanic field to about -8% beneath the GB. Corresponding delay times average 1.5 sec beneath the central CP, decrease to approximately 0.8 sec near the CP-GB transition, and increase to about 1.2 sec beneath the GB. For the central CP, we suggest anisotropy predominantly controlled by North American plate motion above the asthenosphere. The observed pattern of westward-rotating anisotropy from the western CP through the CP-GB transition may be influenced to asthenospheric flow around a CP lithospheric keel and/or by vertical flow arising from edge-driven small-scale convection. The anisotropic transition from the CP to the GB thus marks a first-order change from absolute plate motion dominated lithosphere-asthenosphere shear to a new regime controlled by regional flow processes. The NNW-SSE anisotropic fast directions of split SKS waves in the eastern GB area are part of a broad circular pattern of seismic anisotropic fast direction in the central GB that has recently been hypothesized to be due to toroidal flow around the sinking Juan de Fuca-Gorda slab.National Science Foundation EAR 9706094, 9707188, 9707190, 0207812Los Alamos National Laboratory Institute of Geophysics and Planetary PhysicsNational Science Foundation Cooperative EAR-000430Department of Energy National Nuclear Security AdministrationGeological Science
The preparation of 1, 1\u27tetramethylene ferrocene
The discovery of ferrocene, bis-cyclopentadienyl iron, in 1951 stimulated further research into a relatively new field of Organic Chemistry, organometallies. Ferrocene is the first of a series of transition metal-organic ring compounds in which the metallic atom is bound covalently to two cyclopentadiene rings (Fig III). The rings are superimposed over one another with the single atom inbetween; thus, they are often referred to as âsandwich compounds.â The following procedure is that which Rinehart (11) used to prepare the acid derivative ÎČ-ferrocenoylpropionic acid (VII). The preparation consists of adding 7.4 g. of ferrocene and 2.0 g. of succinic anhydride in 150 ml. of methylene chloride to 5.8 g. of aluminum chloride in 150 ml. of methylene chloride. The reaction was stirred for two hours at room temperature, then decanted over ice. The crude acid was extracted from methylene chloride with sodium carbonate, filtered through Celite, and reprecipitated with dilute hydrochloric acid. The orange acid was recrystallized from methanol-bensene. Results of elemental analysis for carbon, hydrogen, and iron, and infra-red data supported the proposed structure (VIII)
Evidence of ongoing radial migration in NGC 6754: Azimuthal variations of the gas properties
Understanding the nature of spiral structure in disk galaxies is one of the
main, and still unsolved questions in galactic astronomy. However, theoretical
works are proposing new testable predictions whose detection is becoming
feasible with recent development in instrumentation. In particular, streaming
motions along spiral arms are expected to induce azimuthal variations in the
chemical composition of a galaxy at a given galactic radius. In this letter we
analyse the gas content in NGC 6754 with VLT/MUSE data to characterise its 2D
chemical composition and H line-of-sight velocity distribution. We find
that the trailing (leading) edge of the NGC 6754 spiral arms show signatures of
tangentially-slower, radially-outward (tangentially-faster, radially-inward)
streaming motions of metal-rich (poor) gas over a large range of radii. These
results show direct evidence of gas radial migration for the first time. We
compare our results with the gas behaviour in a -body disk simulation
showing spiral morphological features rotating with a similar speed as the gas
at every radius, in good agreement with the observed trend. This indicates that
the spiral arm features in NGC 6754 may be transient and rotate similarly as
the gas does at a large range of radii.Comment: 8 pages, 4 figures, accepted for publication in ApJL 2016 September
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A simulation system for behaviour evaluation of off-rooad mobile robots
Abstract: This study deals with optimization of planetary rover traversability over challenging outdoor terrains. In this aim, it is necessary to simulate rover behaviour on soft soil with a high degree of realism. The paper describes a simulation system for mobile robots evolving on natural and unstructured surfaces. This simulator integrates the whole dynamics of the multibody systems and complex interactions with soft ground as well as control schemes.
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