Search results for "PROB"

Pricing of Forwards and Options in a Multivariate Non-Gaussian Stochastic Volatility Model for Energy Markets

2013

In Benth and Vos (2013) we introduced a multivariate spot price model with stochastic volatility for energy markets which captures characteristic features, such as price spikes, mean reversion, stochastic volatility, and inverse leverage effect as well as dependencies between commodities. In this paper we derive the forward price dynamics based on our multivariate spot price model, providing a very flexible structure for the forward curves, including contango, backwardation, and hump shape. Moreover, a Fourier transform-based method to price options on the forward is described.

Long-term stability of phase-separated half-Heusler compounds

2015

Half-Heusler (HH) compounds have shown high figure of merit up to 1.5. Here, we address the long-term stability of n- and p-type HH materials. For this purpose, we investigated HH materials based on the Ti0.3Zr0.35Hf0.35NiSn-system after 500 cycles (1700 h) from 373 to 873 K. Both compounds exhibit a maximum Seebeck coefficient of |α|≈ 210 μV K(-1) and a phase separation into two HH phases. The dendritic microstructure is temperature resistant and upon cycling the changes in the microstructure are so marginal that the low thermal conductivity values (κ4 W m(-1) K(-1)) could be maintained. Our results emphasize that phase-separated HH compounds are suitable low cost materials and can lead to…

ChemInform Abstract: Relaxation Phenomena of a Triplet Spin Probe in Glassy and Crystalline o-Terphenyl.

2010

The authors used quinoxaline in its photoexcited triplet state as a spin probe in order to measure the spin-lattice relaxation rate in o-terphenyl glass as a function of temperature. They found a power law with an exponent close to 2. Since o-terphenyl can easily be crystallized, they investigated the crystal, too. Below 3.5 K the spin is highly polarized, contrary to the behavior in the glass, where it reaches thermal equilibrium down to the lowest temperatures of their experiment (1.4 K). Around 3.5 K the polarization in the crystal vanishes. Above it appears with opposite sign due to thermal equilibration.

Thermoconvective instability and local thermal non-equilibrium in a porous layer with isoflux-isothermal boundary conditions

2014

The effects of lack of local thermal equilibrium between the solid phase and the fluid phase are taken into account for the convective stability analysis of a horizontal porous layer. The layer is bounded by a pair of plane parallel walls which are impermeable and such that the lower wall is subject to a uniform flux heating, while the upper wall is isothermal. The local thermal non-equilibrium is modelled through a two-temperature formulation of the energy exchange between the phases, resulting in a pair of local energy balance equations: one for each phase. Small-amplitude disturbances of the basic rest state are envisaged to test the stability. Then, the standard normal mode procedure is…

Epistemic and didactic values of the demonstrative process in different cultures: a case study in Geometry with Chinese and Italian students

2011

Thixotropy of Highly Viscous Sodium (Carboxymethyl)cellulose Hydrogels

1997

A general method to quantify the thixotropic behavior of systems with very low thixotropy is proposed. The areas enclosed by the rheograms τ=fγ. must be fitted to functions with well-determined boundary conditions. From these equations the corresponding thixotropic areas are obtained, together with the theoretical area enclosed by the rheogram corresponding to the maximum rheodestruction. The proposed method is applied to high viscosity sodium (carboxymethyl)cellulose gels.

Three solutions for a Neumann boundary value problem involving the p-Laplacian

2005

In this note we prove the existence of an open interval ]λ', λ"[ for each λ of which a Neumann boundary value problem involving the p-Laplacian and depending on λ admits at least three solutions. The result is based on a recent three critical points theorem.

A G468-T AMPD1 mutant allele contributes to the high incidence of myoadenylate deaminase deficiency in the Caucasian population.

2002

Myoadenylate deaminase deficiency is the most common metabolic disorder of skeletal muscle in the Caucasian population, affecting approximately 2% of all individuals. Although most deficient subjects are asymptomatic, some suffer from exercise-induced myalgia suggesting a causal relationship between a lack of enzyme activity and muscle function. In addition, carriers of this derangement in purine nucleotide catabolism may have an adaptive advantage related to clinical outcome in heart disease. The molecular basis of myoadenylate deaminase deficiency in Caucasians has been attributed to a single mutant allele characterized by double C to T transitions at nucleotides +34 and +143 in mRNA enco…

A novel mutation (Thr116IIe) in the presenilin 1 gene in a patient with early-onset Alzheimer's disease

2004

We report a novel presenilin 1 (PSN1) mutation (Thr116Ile) in a woman with early onset Alzheimer's disease (AD). This mutation was not found in 100 healthy controls, indicating that this is not a common polymorphism. The patient presented with forgetfulness at age 45, followed over the next 3 years by a worsening of the memory loss and frequent episodes of confusion and spatial disorientation. Neuroimaging studies were consistent with AD. The analysis of the family's pedigree showed that the proband was apparently the only member affected. Because the early death of several close relatives (i.e. the mother and the grandmother) and the demonstration that the father is not a mutation carrier,…

Methods for evaluating causality in observational studies.

2019

BACKGROUND: In clinical medical research, causality is demonstrated by randomized controlled trials (RCTs). Often, however, an RCT cannot be conducted for ethical reasons, and sometimes for practical reasons as well. In such cases, knowledge can be derived from an observational study instead. In this article, we present two methods that have not been widely used in medical research to date. METHODS: The methods of assessing causal inferences in observational studies are described on the basis of publications retrieved by a selective literature search. RESULTS: Two relatively new approaches—regression-discontinuity methods and interrupted time series—can be used to demonstrate a causal relat…