Rheology of bidisperse non-Brownian suspensions

We study the rheology of bidisperse non-Brownian suspensions using particle-based simulation, mapping the viscosity as a function of the size ratio of the species, their relative abundance, and the overall solid content. The variation of the viscosity with applied stress exhibits paradigmatic shear thickening phenomenology irrespective of composition, though the stress-dependent limiting solids fraction governing the viscosity and its divergence point are non-monotonic in the mixing ratio. Contact force data demonstrate an exchange in dominant stress contribution from large-large to small-small particle contacts as the mixing ratio of the species evolves. Combining a prior model for shear thickening with one for composition-dependent jamming, we obtain a full description of the rheology of bidisperse non-Brownian suspensions capable of predicting effects such as the viscosity reduction observed upon adding small particle fines to a suspension of large particles.Comment: 5 pages, 4 figure

A simulation of the insurance industry: The problem of risk model homogeneity

We develop an agent-based simulation of the catastrophe insurance and reinsurance industry and use it to study the problem of risk model homogeneity. The model simulates the balance sheets of insurance firms, who collect premiums from clients in return for ensuring them against intermittent, heavy-tailed risks. Firms manage their capital and pay dividends to their investors, and use either reinsurance contracts or cat bonds to hedge their tail risk. The model generates plausible time series of profits and losses and recovers stylized facts, such as the insurance cycle and the emergence of asymmetric, long tailed firm size distributions. We use the model to investigate the problem of risk model homogeneity. Under Solvency II, insurance companies are required to use only certified risk models. This has led to a situation in which only a few firms provide risk models, creating a systemic fragility to the errors in these models. We demonstrate that using too few models increases the risk of nonpayment and default while lowering profits for the industry as a whole. The presence of the reinsurance industry ameliorates the problem but does not remove it. Our results suggest that it would be valuable for regulators to incentivize model diversity. The framework we develop here provides a first step toward a simulation model of the insurance industry for testing policies and strategies for better capital management

CAST constraints on the axion-electron coupling

In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axiorecombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling gae and axion-photon interaction strength ga using the CAST phase-I data (vacuum phase). For ma <~ 10 meV/c2 we find ga gae < 8.1 × 10−23 GeV−1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission

Measurement of the Lifetime Difference Between B_s Mass Eigenstates

We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion

Методика обучения иноязычному профессионально-ориентированному общению научно-педагогических работников неязыкового вуза

Настоящее исследование рассматривает проблему формирования иноязычной коммуникативной компетенции взрослых обучающихся на основе использования аутентичных материалов. Для формирования иноязычной коммуникативной компетенции были определены (личностно-ориентированный и компетентностный) подходы обучения. Выявлены теоретико-методологические основы обучения устному иноязычному общению научно-педагогических работников неязыкового вуза. В работе с различных позиций научно обоснованы теоретические положения, раскрывающие специфику процесса обучения устному иноязычному общению взрослых с использованием аутентичных (печатных, аудио и видео) материалов, произведен анализ различных методик и принципов обучения, учитывающих своеобразие и особенности взрослого человека.The present paper researches the problem of foreign-language communicative competence of adult learners on the basis of authentic materials. Learner-centered and competence approaches were determined to form a foreign-language communicative competence.Theoretical and methodological backgrounds of oral foreign language communication of non-linguistic academic staff were formed. Theoretical backgrounds showing oral foreign language communication teaching techniques with the help of authentic materials(printed, audio, video) were proved, different methods and teaching techniques were analyzed taking into account the peculiarities of adult learners. As a result of conducted scientific research the theoretically proved and experimentally tested methodology (set of exercises with the use of aut

Traditional knowledge of wild edible plants used in the northwest of the Iberian Peninsula (Spain and Portugal): a comparative study

<p>Abstract</p> <p>Background</p> <p>We compare traditional knowledge and use of wild edible plants in six rural regions of the northwest of the Iberian Peninsula as follows: Campoo, Picos de Europa, Piloña, Sanabria and Caurel in Spain and Parque Natural de Montesinho in Portugal.</p> <p>Methods</p> <p>Data on the use of 97 species were collected through informed consent semi-structured interviews with local informants. A semi-quantitative approach was used to document the relative importance of each species and to indicate differences in selection criteria for consuming wild food species in the regions studied.</p> <p>Results and discussion</p> <p>The most significant species include many wild berries and nuts (e.g. <it>Castanea sativa, Rubus ulmifolius, Fragaria vesca</it>) and the most popular species in each food-category (e.g. fruits or herbs used to prepare liqueurs such as <it>Prunus spinosa</it>, vegetables such as <it>Rumex acetosa</it>, condiments such as <it>Origanum vulgare</it>, or plants used to prepare herbal teas such as <it>Chamaemelum nobile</it>). The most important species in the study area as a whole are consumed at five or all six of the survey sites.</p> <p>Conclusion</p> <p>Social, economic and cultural factors, such as poor communications, fads and direct contact with nature in everyday life should be taken into account in determining why some wild foods and traditional vegetables have been consumed, but others not. They may be even more important than biological factors such as richness and abundance of wild edible flora. Although most are no longer consumed, demand is growing for those regarded as local specialties that reflect regional identity.</p