Polynomial chaos for simulating random volatilities

In financial mathematics, the fair price of options can be achieved by solutions of parabolic differential equations. The volatility usually enters the model as a constant parameter. However, since this constant has to be estimated with respect to the underlying market, it makes sense to replace the volatility by an according random variable. Consequently, a differential equation with stochastic input occurs, whose solution determines the fair price in the refined model. Corresponding expected values and variances can be computed approximately via a Monte Carlo method. Alternatively, the generalised polynomial chaos yields an efficient approach for calculating the required data. Based on a parabolic equation modelling the fair price of Asian options, the technique is developed and corresponding numerical simulations are presented.     

Electrodeposited Al–Mn alloys with microcrystalline,nanocrystalline, amorphous and nano-quasicrystalline structures

Al–Mn alloys with Mn content ranging from 0 to 15.8 at.% are prepared by electrodeposition from an ionic liquid at room temperature, and exhibit a remarkably broad range of structures. The alloys are characterized through a combination of techniques, including X-ray diffraction, electron microscopy and calorimetry. For alloys with Mn content up to 7.5 at.%, increasing Mn additions lead to a decrease in grain size of single-phase microcrystalline face-centered cubic (fcc) Al(Mn). Between 8.2 and 12.3 at.% Mn, an amorphous phase appears, accompanied by a dramatic reduction in the size of the coexisting fcc crystallites to the ～2–50 nm level. At higher Mn contents, the structure nominally appears entirely amorphous, but is shown to contain order in the form of pre-existing nuclei of the icosahedral quasicrystalline phase. Additionally, nanoindentation tests reveal that the nanostructured and amorphous specimens have very high hardnesses that exhibit complex trends with Mn content.     

Effects of field-manure applications on stratified 17β-estradiol concentrations

The occurrence of the manure-borne estrogen, 17β-estradiol (E2), was investigated in laboratory and field soils. In the laboratory, E2 was applied to soil to simulate concentrations found in swine (Sus scrofa domestica) manure (5000 ng L⁻¹). The aqueous-extracted E2 dissipated in the soil by 98% within 1 h and was not significantly different from background concentrations (18 ng L⁻¹) for the duration of the experiment (64 h). In the field study, soil cores were taken before and several dates after swine manure application. Equivalent porewater concentrations of water-extractable E2 were determined in 0.15-m increments down to the water table (0.70-2.00 m deep). The average frequency of detection for 168 samples was 38% (average = 40 ng L⁻¹ porewater equivalents). Eleven days after manure application there was no significant effect on E2 detection frequency or concentration. However, E2 concentrations significantly increased by 6 months after manure application, and appeared to be related to precipitation. Concentrations then returned to original levels by 17 months after manure application. Manure did not have an immediate effect on E2 occurrence due to the capacity of the soil to rapidly sorb E2. However, it appears that soil may act as a long-term reservoir for E2 in the environment, which may be periodically released through desorption.     

Threats and benefits of power discrepancies between organisations: a supply chain perspective

The discrepancy of power between organisations has raised concerns over the abuse of power in inter-organisational relationships, especially in the supply chain where parties often have different power positions. In this study, we develop and test a model that explains how the less powerful party may react to different forms of power exercised by the power source. Nowadays, customers are typically more powerful than manufacturers in supply chains. Specifically, based on data from 617 manufacturers representing various organisational sizes and industries, we examine the impact of customer coercive and expert power on the manufacturer’s information sharing behaviours (information systems and content) as well as the performance implications for both the manufacturer and the customer. Structural equation modelling reveals that customer expert power positively predicts the establishment of information systems and the extent to which information is actively shared. In contrast, customer coercive power is negatively associated with the establishment of information systems, while it is positively related to information content. Information systems, in turn, predict the extent to which information is effectively exchanged, which ultimately relates positively to flexibility and delivery performance. Flexibility performance is positively related to financial performance, while delivery performance is not. Taken together, these findings enrich our understanding of inter-organisational power dynamics by offering important insights into differential reactions that the power target may choose to counter power imbalances.     

Universal features of grain boundary networks in FCC materials

Grain boundary character distributions and triple junction distributions have been determined for 70 experimental microstructures, comprising aluminum-, copper-, austenitic iron- and nickel-based alloys in a wide variety of processed states. In these FCC metals, the fraction of coincidence site lattice (CSL) boundaries ranges from about 12% (as for a random Mackenzie distribution) to values as high as 75%. Despite wide variations in composition, processing, and grain size, we find that the grain boundary character distribution and triple junction distributions of these materials have striking similarities, and can be described by just a few parameters. This universality arises due to the highly non-random laws that govern the assembly of the grain boundary network, and due to the kinematic limitation that CSL boundaries arise primarily through twinning.     

Double-resonance Semiconductor Superlattice Parametric Oscillator for Generation of Subterahertz Radiation

We report on a subterahertz superlattice parametric oscillator that operated simultaneously at two different harmonic frequencies of a microwave pump field. A pump field (frequency near 100 GHz) was coupled to a GaAs/AlAs superlattice in a resonator for the third and the fifth harmonic. The pump field produced a third harmonic field and this together with the pump field created a fifth harmonic field. A theoretical analysis indicates that the nonlinearity, which is based on the dynamics of miniband electrons, should allow for the upconversion of pump radiation of higher frequency into the terahertz frequency range.     

Corporate Reputation Effects Across Nations: The Impact of Country Distances and Firm-Specific Resources

CEOs are responsible for the development of a strong corporate reputation, which is increasingly used by multinational corporations as an important differentiation criterion in foreign markets. Because the effects of an often centrally managed but locally perceived reputation are likely to vary between countries, this study analyzes the moderating role of institutional distance and firm-specific resources on reputation effects in the chemical and pharmaceutical industry, two important aspects that have not been considered in consumer-centered corporate reputation research so far. The authors refer to signaling theory—advanced by institutional and resource-based thinking—and use data from 29,987 consumer evaluations of a multinational corporation in 43 countries. The results of the multilevel models indicate that distance between home and host countries weakens reputation effects on both consumer loyalty and trust, whereas firm-specific resources reinforce these effects. In particular, country experience and cultural-cognitive distance are important when managing reputations across nations because they explain high amounts of country-level variance.     

Atomistic basis for the plastic yield criterion of metallic glass

Because of their disordered atomic structure, amorphous metals (termed metallic glasses) have fundamentally different deformation mechanisms compared with polycrystalline metals. These different mechanisms give metallic glasses high strength, but the extent to which they affect other macroscopic deformation properties is uncertain. For example, the nature of the plastic-yield criterion is a point of contention, with some studies reporting yield behaviour roughly in line with that of polycrystalline metals, and others indicating strong fundamental differences. In particular, it is unclear whether pressure- or normal stress-dependence needs to be included in the plastic-yield criterion of metallic glasses, and how such a dependence could arise from their disordered structure. In this work we provide an atomic-level explanation for pressure-dependent yield in amorphous metals, based on an elementary unit of deformation. This simple model compares favourably with new atomistic simulations of metallic glasses, as well as existing experimental data.