Exchange Design and Efficiency

Most assets clear independently rather than jointly. This paper presents a model based on the uniform‐price double auction which accommodates arbitrary restrictions on market clearing, including independent clearing across assets (allowed when demand for each asset is contingent only on the price of that asset) and joint market clearing for all assets (required when demand for each asset is contingent on the prices of all assets). Additional trading protocols for traded assets—neutral when the market clears jointly—are generally not redundant innovations, even if all traders participate in all protocols. Multiple trading protocols that clear independently can be designed to be at least as efficient as joint market clearing for all assets. The change in price impact brought by independence in market clearing can overcome the loss of information, and enhance diversification and risk sharing. Except when the market is competitive, market characteristics should guide innovation in trading technology

Ambiguity in dynamic contracts

We study a continuous-time principal-agent model in which the principal is ambiguity averse about the agent's effort cost. The robust contract generates a seemingly excessive pay-performance sensitivity. The worst-case effort cost is high after good performance, but low after bad performance, which leads to overcompensation and undercompensation respectively and provides a new rationale for performance-sensitive debt. We also characterize the agent's incentives when the contract is misspecified, i.e., he is offered the robust contract, but his true effort cost differs from the worst case. Then, termination can induce shirking, the strength of incentives is hump-shaped, and agents close to firing prefer riskier projects, while those close to getting paid prefer safer ones. This feature resembles careers in organizations, most notably risk-shifting and the quiet life

Weakening of the stratospheric polar vortex by Arctic sea-ice loss

Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea-ice, the mechanism that links sea-ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea-ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea-ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhances the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January-February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.open11167174Ysciescopu

Microspore derived embryo formation and doubled haploid plant production in broccoli (Brassica oleracea L. var italica) according to nutritional and environmental conditions

In cell culture, the maintenance of proper growing conditions is a key approach for improving the formation of embryos, and is useful in the production of doubled haploid (DH) plants. Optimal nutritional and environmental conditions for the microspore culture of Brassica oleracea L. var italica were determined in order to reduce time and effort in breeding. The optimal conditions for microspore embryo formation differed depending on genotype. Microspore-derived embryos (MDE) formation was influenced by the strength of the NLN medium, the microelement and sugar concentration, and the heat shock temperature and period. The 0.5XNLN liquid medium was the most favorable for MDE formation. The most efficient formation of MDE was observed in the 0.5X NLN liquid medium, without the addition of microelements. When 13 or 15% sucrose was added to the 0.5X NLN liquid medium, the amount of normal MDE formation increased. The optimum heat shock temperature and period for MDE formation was 32.5°C and 24 h, respectively. A polyploidy test indicated that 30% of the microspore derived plants were diploid throughout the embryogenesis process.Key words: Embryogenesis, heat shock, microelements, NLN medium, polyploidy test

Iron Nanoparticle-induced activation of plasma membrane H+-ATPase Promotes Stomatal Opening in Arabidopsis thaliana

Engineered nanomaterials (ENMs) enable the control and exploration of intermolecular interactions inside microscopic systems, but the potential environmental impacts of their inevitable release remain largely unknown. Plants exposed to ENMs display effects, such as increase in biomass and chlorophyll, distinct from those induced by exposure to their bulk counterparts, but few studies have addressed the mechanisms underlying such physiological results. The current investigation found that exposure of Arabidopsis thaliana to nano zerovalent iron (nZVI) triggered high plasma membrane H+-ATPase activity. The increase in activity caused a decrease in apoplastic pH, an increase in leaf area, and also wider stomatal aperture. Analysis of gene expression indicated that the levels of the H+-ATPase isoform responsible for stomatal opening, AHA2, were 5-fold higher in plants exposed to nZVI than in unexposed control plants. This is the first study to show that nZVI enhances stomatal opening by inducing the activation of plasma membrane H+-ATPase, leading to the possibility of increased CO2 uptake.X112119Ysciescopu

Two-dimensional imaging of edge-localized modes in KSTAR plasmas unperturbed and perturbed by n=1 external magnetic fields

The temporal evolution of edge-localized modes (ELMs) has been studied using a 2-D electron cyclotron emission imaging system in the KSTAR tokamak. The ELMs are observed to evolve in three distinctive stages: the initial linear growth of multiple filamentary structures having a net poloidal rotation, the interim state of regularly spaced saturated filaments, and the final crash through a short transient phase characterized by abrupt changes in the relative amplitudes and distance among filaments. The crash phase, typically consisted of multiple bursts of a single filament, involves a complex dynamics, poloidal elongation of the bursting filament, development of a fingerlike bulge, and fast localized burst through the finger. Substantial alterations of the ELM dynamics, such as mode number, poloidal rotation, and crash time scale, have been observed under external magnetic perturbations with the toroidal mode number n = 1. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3694842]X1125sciescopu

Benefits of greenhouse gas mitigation on the supply, management, and use of water resources in the United States

Climate change impacts on water resources in the United States are likely to be far-reaching and substantial because the water is integral to climate, and the water sector spans many parts of the economy. This paper estimates impacts and damages from five water resource-related models addressing runoff, drought risk, economics of water supply/demand, water stress, and flooding damages. The models differ in the water system assessed, spatial scale, and unit of assessment, but together provide a quantitative and descriptive richness in characterizing water sector effects that no single model can capture. The results, driven by a consistent set of greenhouse gas (GHG) emission and climate scenarios, examine uncertainty from emissions, climate sensitivity, and climate model selection. While calculating the net impact of climate change on the water sector as a whole may be impractical, broad conclusions can be drawn regarding patterns of change and benefits of GHG mitigation. Four key findings emerge: 1) GHG mitigation substantially reduces hydro-climatic impacts on the water sector; 2) GHG mitigation provides substantial national economic benefits in water resources related sectors; 3) the models show a strong signal of wetting for the Eastern US and a strong signal of drying in the Southwest; and 4) unmanaged hydrologic systems impacts show strong correlation with the change in magnitude and direction of precipitation and temperature from climate models, but managed water resource systems and regional economic systems show lower correlation with changes in climate variables due to non-linearities created by water infrastructure and the socio-economic changes in non-climate driven water demand

Intraductal papillary mucinous tumor of bile ducts radiologic and pathologic features: a case report

We report a case of a 67-year-old Caucasian man with right upper quadrant abdominal pain. He underwent radiologic investigations that revealed a solid, focal mass, at the V hepatic segment. Because a definitive diagnosis, based on imaging appearance of the lesion, was impossible in our case, we performed a hystopathological investigation but the biopsies were inconclusive. So, the definitive diagnosis of intraductal papillary mucinous tumor of bile ducts was made on surgical resected material

Highly Conductive Graphene/Ag Hybrid Fibers for Flexible Fiber-Type Transistors

Mechanically robust, flexible, and electrically conductive textiles are highly suitable for use in wearable electronic applications. In this study, highly conductive and flexible graphene/Ag hybrid fibers were prepared and used as electrodes for planar and fiber-type transistors. The graphene/Ag hybrid fibers were fabricated by the wet-spinning/drawing of giant graphene oxide and subsequent functionalization with Ag nanoparticles. The graphene/Ag hybrid fibers exhibited record-high electrical conductivity of up to 15,800 S cm(-1). As the graphene/Ag hybrid fibers can be easily cut and placed onto flexible substrates by simply gluing or stitching, ion gel-gated planar transistors were fabricated by using the hybrid fibers as source, drain, and gate electrodes. Finally, fibertype transistors were constructed by embedding the graphene/Ag hybrid fiber electrodes onto conventional polyurethane monofilaments, which exhibited excellent flexibility (highly bendable and rollable properties), high electrical performance (mu(h) = 15.6 cm(2) V-1 s(-1), I-on/I-off > 10(4)), and outstanding device performance stability (stable after 1,000 cycles of bending tests and being exposed for 30 days to ambient conditions). We believe that our simple methods for the fabrication of graphene/Ag hybrid fiber electrodes for use in fiber-type transistors can potentially be applied to the development all-organic wearable devices.111912Ysciescopu

Seed-layer mediated orientation evolution in dielectric Bi-Zn-Ti-Nb-O thin films

Highly (hhh) -oriented pyrochlore Bi-Zn-Ti-Nb-O (BZTN) thin films were fabricated via metal-organic decomposition using orientation template layers. The preferred orientation was ascribed to the interfacial layer, the lattice parameter of which is similar to BZTN. High-resolution transmission electron microscopy supported that the interfacial layer consists of Bi and Pt. The (hhh) -oriented thin films exhibited a highly insulating nature enabling feasible applications in electronic devices, particularly voltage tunable application. The BZTN thin films did not show any apparent dielectric anisotropy and the slightly enhanced dielectric properties were discussed in connection to the internal stress and the grain boundary effect. © 2007 American Institute of Physics