HART EFFECT AND EQUILIBRIUM IN INCOMPLETE MARKETS I

In this paper I reconsider the problem of the existence for GEI models. It is well known that existence for this kind of models can fail since there are bad spot prices. Using tools from Algebraic Geometry I show that the set of bad spot prices is tipically empty if the information tree, the number of secruities and the number of tradable goods at each node satisfy a well defined inequality. Even if such inequality is not staisfied I show that the set of bad spot price can be fully characterized and described using an algorithm and I give an universal bound for the cardinality of this set. Moreover, using these results, I prove that the equilibrium always exists for all endowment profiles.

Incomplete markets with no Hart points

We provide a geometric test of whether a general equilibrium incomplete markets (GEI) economy has Hart points---points at which the rank of the securities payoff matrix drops. Condition (H) says that, at each nonterminal node, there is an affine set (of appropriate dimension) that intersects all of a well-specified set of convex polyhedra. If the economy has Hart points, then Condition (H) is satisfied; consequently, if condition (H) fails, the economy has no Hart points. The shapes of the convex polyhedra are determined by the number of physical goods and the dividends of the securities, but are independent of the endowments and preferences of the agents. Condition (H) fails, and thus there are no Hart points, in interesting classes of economies with only short-lived securities, including economies obtained by discretizing an economy with a continuum of states and sufficiently diverse payoffs.Incomplete Markets, GEI model, Hart points

Market Clearing and Derivative Pricing.

We develop a method of assigning unique prices to derivative securities, including options, in the continuous-time finance models developed in Raimondo [45] and Anderson and Raimondo [6]. In contrast with the martingale method of valuing options, which cannot distinguish among infinitely many possible option pricing processes for a given underlying securities price process when markets are dynamically incomplete, our option prices are uniquely determined in equilibrium as a function of the underlying economic data and the underlying securities price process; in the single-agent model, this function is given in closed form.

Towards a Model-Based Field-Frequency Lock for Fast-Field Cycling NMR

Fast-field cycling nuclear magnetic resonance (FFC NMR) relaxometry allows to investigate molecular dynamics of complex materials. FFC relaxometry experiments require the magnetic field to reach different values in few milliseconds and field oscillations to stay within few ppms during signal acquisition. Such specifications require the introduction of a novel field-frequency lock (FFL) system. In fact, control schemes based only on current feedback may not guarantee field stability, while standard FFLs are designed to handle very slow field fluctuations, such as thermal derives, and may be ineffective in rejecting faster ones. The aim of this work is then to propose a methodology for the synthesis of a regulator that guarantees rejection of field fluctuations and short settling time. Experimental trials are performed for both model validation and evaluation of the closed-loop performances. Relaxometry experiments are performed to verify the improvement obtained with the new FFL. The results highlight the reliability of the model and the effectiveness of the overall approach

Effect of Substrates and Thermal Treatments on Metalorganic Chemical Vapor Deposition-Grown Sb2Te3 Thin Films

Antimony telluride (Sb2Te3) thin films were obtained by metalorganic chemical vapor deposition (MOCVD). The films were grown on crystalline Si(100) and Al2O3(0001) and amorphous SiO2 and alpha-Al2O3 substrates. Their structural properties were compared with those of the Sb2Te3/Si(111) heterostructure. In addition to the effect of the substrate, the influence of pre- and post-growth thermal annealing is also presented. The quality of the films is discussed by comparing their morphological properties, such as roughness and granularity, and ascertaining their crystallinity and their in-plane and out-of-plane orientation

UV irradiated graphene-based nanocomposites: Change in the mechanical properties by local harmoniX atomic force microscopy detection

Epoxy based coatings are susceptible to ultra violet (UV) damage and their durability can be significantly reduced in outdoor environments. This paper highlights a relevant property of graphene-based nanoparticles: Graphene Nanoplatelets (GNPs) incorporated in an epoxy-based free-standing film determine a strong decrease of the mechanical damages caused by UV irradiation. The effects of UV light on the morphology and mechanical properties of the solidified nanocharged epoxy films are investigated by Atomic Force Microscopy (AFM), in the acquisition mode "HarmoniX." Nanometric-resolved maps of the mechanical properties of the multi-phase material evidence that the incorporation of low percentages, between 0.1% and 1.0% by weight, of graphene nanoplatelets (GNPs) in the polymeric film causes a relevant enhancement in the mechanical stability of the irradiated films. The beneficial effect progressively increases with increasing GNP percentage. The paper also highlights the potentiality of AFM microscopy, in the acquisition mode "HarmoniX" for studying multiphase polymeric systems

Amplified spontaneous emission in quaterthiophene single crystals

The authors demonstrate amplified spontaneous emission (ASE) from quaterthiophene single crystals and study its behavior at low temperature. The room temperature photoluminescence exhibits line narrowing (spectral width down to 10nm) at 553nm for excitation fluence larger than 1mJcm−2. At low temperature (10K), ASE is observed from two vibronic transitions at 510nm (0-1) and 553nm (0–2), with line narrowing down to 5A, for fluences larger than 100μJcm−2. The stimulated emission cross section is of the order of 10−15cm2, and the ASE is found to be strongly affected by thermally induced dynamic disorder. The emission stability under photopumping is also studied and discussed