A Central Limit Theorem, Loss Aversion and Multi-Armed Bandits

This paper establishes a central limit theorem under the assumption that conditional variances can vary in a largely unstructured history-dependent way across experiments subject only to the restriction that they lie in a fixed interval. Limits take a novel and tractable form, and are expressed in terms of oscillating Brownian motion. A second contribution is application of this result to a class of multi-armed bandit problems where the decision-maker is loss averse

When Online Reviews Meet Hyperdifferentiation: A Study of the Craft Beer Industry

We analyze how online reviews are used to evaluate the effectiveness of product differentiation strategies based on the theories of hyperdifferentiation and resonance marketing. Hyperdifferentiation says that firms can now produce almost anything that appeals to consumers and they can manage the complexity of the increasingly diverse product portfolios that result. Resonance marketing says that informed consumers will purchase products that they actually truly want. When consumers become more informed, firms that provide highly differentiated products should experience higher growth rates than firms with less differentiated offerings. We construct measures of product positioning based on online ratings and find supportive evidence using sales data from the craft beer industry. In particular, we find that the variance of ratings and the strength of the most positive quartile of reviews play a significant role in determining which new products grow fastest in the market-place. This supports our expectations for resonance marketing

Modelling the Long-Term Impact on Herder Incomes and Environmental Services in an Uncertain World

Environmental, market and political influences affect herders’ livelihoods with the expectation that they maintain biologically and economically resilient systems. To balance these external influences and the trade-offs within a grassland system it involves the consideration of interactions between grassland ecology, technology use, environmental externalities, utilisation by grazing animals for food and fibre production, and the long-term profitability of the farming system. Many of these variables are slow-moving and are trade-offs are most efficiently studied with models. The StageTHREE Sustainable Grasslands Model, which utilizes the core functions and dynamics of more mechanistic tools, has been designed to minimize the skill and data required for parameterisation. It allows the key dynamics of the grassland systems to be incorporated along with the stochasticity of the system, in terms of both the uncertainty of the production and market environment. This enables an investigation into the sustainability and environmental impacts of alternative livestock management practices, so that these can be evaluated in relation to policy options. This paper presents an insight into the integration of herder level bioeconomic modelling for the analysis of grassland policy impacts in Mongolia and China. The research highlights that policy settings that reduce stocking rates can improve the environmental services from grasslands, and in most cases, also improve herder livelihoods and resilience

Management Changes and Strategies to Improve the Environmental Services from Grasslands in Northern China and Mongolia

The grasslands of Mongolia and northern China are part of the vast Eurasian grasslands that extend from east Asia to eastern Europe, with many common problems. Grassland degradation and herder livelihoods in the steppe regions of China and Mongolia are widely acknowledged as major issues that need to be improved. The core problem is too many animals are now grazing grasslands, initially driven by significant policy changes, and decisions that assumed more animals would lift herder incomes. Problems are accentuated by poorly defined property rights over the land. The effectiveness of current Government Programs aimed at reducing grazing pressures has been questioned, especially for their ability to deliver better environmental outcomes without impacting herder livelihoods. This panel session examines ways to understand the opportunities for improvement of grasslands. This first paper outlines some general aspects of the pastoral sectors, and management responses and strategies that can improve the services from grasslands

Fermi Surface and Band Renormalization in (Sr,K)Fe2_2As2_2 Superconductor from Angle-Resolved Photoemission Spectroscopy

High resolution angle-resolved photoemission measurements have been carried out on (Sr,K)Fe$_2$As$_2$ superconductor (Tc=21 K). Three hole-like Fermi surface sheets are clearly resolved for the first time around the Gamma point. The overall electronic structure shows significant difference from the band structure calculations. Qualitative agreement between the measured and calculated band structure is realized by assuming a chemical potential shift of -0.2 eV. The obvious band renormalization suggests the importance of electron correlation in understanding the electronic structure of the Fe-based compounds.Comment: 4 pages, 4 figure

p-Type Co Interstitial Defects in Thermoelectric Skutterudite CoSb_3 Due to the Breakage of Sb_4-Rings

Skutterudite CoSb_3 based thermoelectric devices have high potential for engineering applications because both n- and p-type doped CoSb_3 demonstrate excellent thermoelectric performance. A crucial point concerning the application of CoSb_3 is to understand and control its defect chemistry. To reveal the native conductivity behavior of nonstoichiometric CoSb_3, we investigated the intrinsic point defects in CoSb_3 using density functional theory. We found CoSb_3 is p-type in either Co or Sb rich regions of phase stability. Interstitial Co (Co_i) and interstitial Co-pair (Co_(i-p)) are the dominant point defects in the Co rich region. However, Co_(i-p) will be difficult to form because the formation temperature of Co_(i-p) is much lower than the synthesis temperature of CoSb_3. The unexpected acceptor nature of the Co_i or Co_(i-p) defects is explained by the breakage of multiple Sb_4-rings. Co vacancy (Co_v) is found to be the p-type defect in the Sb rich region. Furthermore, the solubility of excess Co in CoSb_3 is expected to be larger than that of Sb because of the lower formation energy and higher carrier concentration of Co_i compared with those of Co_v

Diabetes impairs wound healing by Dnmt1-dependent dysregulation of hematopoietic stem cells differentiation towards macrophages

People with type 2 diabetes mellitus (T2DM) have a 25-fold higher risk of limb loss than non-diabetics due in large part to impaired wound healing. Here, we show that the impaired wound healing phenotype found in T2D mice is recapitulated in lethally irradiated wild type recipients, whose hematopoiesis is reconstituted with hematopoietic stem cells (HSCs) from T2D mice, indicating an HSC-autonomous mechanism. This impaired wound healing phenotype of T2D mice is due to a Nox-2-dependent increase in HSC oxidant stress that decreases microRNA let-7d-3p, which, in turn, directly upregulates Dnmt1, leading to the hypermethylation of Notch1, PU.1, and Klf4. This HSC-autonomous mechanism reduces the number of wound macrophages and skews their polarization towards M1 macrophages. These findings reveal a novel inflammatory mechanism by which a metabolic disorder induces an epigenetic mechanism in HSCs, which predetermines the gene expression of terminally differentiated inflammatory cells that controls their number and function