The role of technological availability for the distributive impacts of climate change mitigation policy

The impacts of the availability of low-carbon technologies on the regional distribution of mitigation costs are analyzed in a global multi-regional integrated assessment model. Three effects on regional consumption losses are distinguished: domestic measures, trade of fossil energy carriers and trade of emission permits. Key results are: (i) GDP losses and a redirection of investments in the energy system towards capital-intensive technologies are major contributions to regional consumption losses. (ii) A devaluation of tradable fossil energy endowments contributes largely to the mitigation costs of fossil fuel exporters. (iii) In case of reduced availability of low-carbon technologies, the permit market volume and associated monetary redistributions increase. The results suggest that the availability of a broad portfolio of low-carbon technologies could facilitate negotiations on the permit allocation scheme in a global cap-and-trade system.     

Solubility Limits of Cholesterol, Lanosterol, Ergosterol, Stigmasterol, and β-Sitosterol in Electroformed Lipid Vesicles

Here we use nuclear magnetic resonance to measure the solubility limit of several biologically relevant sterols in electroformed giant unilamellar vesicle membranes containing phosphatidylcholine (PC) lipids in ratios of 1:1:X DOPC:DPPC:sterol. We find solubility limits of cholesterol, lanosterol, ergosterol, stigmasterol, and β-sitosterol to be 65-70%, ~35%, 30-35%, 20-25%, and ~40%, respectively. The low solubilities of stigmasterol and β-sitosterol, which differ from cholesterol only in their alkyl tails, show that subtle differences in tail structure can strongly affect sterol solubility. Below the solubility limits, the fraction of sterol to PC-lipid in electroformed vesicles linearly reflects the fraction in the original stock solutions used in the electroformation process.     

Effects of relative humidity,temperature, and population density on production of cuticular hydrocarbons in housefly Musca domestica L

The production of cuticular hydrocarbons by both males and females of Musca domestica L. under very wet conditions (90% relative humidity) compared to the production at 50 and 20% relative humidity is delayed up to at least 3 days after emergence from the pupae. Eight days after emergence, however, males contain the same amounts of hydrocarbons at 90, 50, and 20% relative humidity, whereas females at 90% still possess less of these substances than at 50 and 20%. It is suggested that this is due to the fact that males, being more active than females, need more cuticular hydrocarbons to prevent water loss. No indication is found that relative humidity has a different effect on the production of the sex pheromone, muscalure [(Z)-9-tricosene] by females than on the production of the other hydrocarbons. Male and female flies produce more hydrocarbons at 35°C than at 20°C. On females, the relative amounts of nonacosane and methyl- and dimethylnonacosanes are significantly higher at 35°C than at 20°C. Female flies produce some (Z)-9-tricosene after eight generations at low population density in contrast to females at high population density, which did not produce muscalure. We suggest that because of the relatively large contribution to the total population, the properties of a small number of females are likely to be expressed sooner in the next generations of small populations than in those of large populations.     

The UCSC Kestrel parallel processor

The architectural landscape of high-performance computing stretches from superscalar uniprocessor to explicitly parallel systems, to dedicated hardware implementations of algorithms. Single-purpose hardware can achieve the highest performance and uniprocessors can be the most programmable. Between these extremes, programmable and reconfigurable architectures provide a wide range of choice in flexibility, programmability, computational density, and performance. The UCSC Kestrel parallel processor strives to attain single-purpose performance while maintaining user programmability. Kestrel is a single-instruction stream, multiple-data stream (SIMD) parallel processor with a 512-element linear array of 8-bit processing elements. The system design focuses on efficient high-throughput DNA and protein sequence analysis, but its programmability enables high performance on computational chemistry, image processing, machine learning, and other applications. The Kestrel system has had unexpected longevity in its utility due to a careful design and analysis process. Experience with the system leads to the conclusion that programmable SIMD architectures can excel in both programmability and performance. This work presents the architecture, implementation, applications, and observations of the Kestrel project at the University of California at Santa Cruz.     

Electron Paramagnetic Resonance of Tb3+ Ions in YBa2Cu3O6

The first observation of electron paramagnetic resonance (EPR) of Tb³⁺ doped into YBa₂Cu₃O₆ is reported. EPR is used to determine the local symmetry of the rare-earth ion and to study the effect of suppression of high-T _c superconductivity by doping. The distance between the lowest singlets of Tb³⁺ ion 7.1 GHz 0.24 cm^–1 and g-factor g 17.9 have been estimated from measurements. Both these parameters are in a good agreement with the corresponding calculated values. No evidence of Tb⁴⁺ ions was found.     

Influence of the preparation conditions on the synthesis of high surface area SiC for use as a heterogeneous catalyst support

The influence of different parameters (temperature, duration and SiO source) on the synthesis of silicon carbide SiC according to the gas-solid reaction between SiO vapors and activated charcoal was investigated. The material obtained retained the general shape of the activated charcoal, which is an advantage because of the difficulty in post shaping SiC, due to the high strength of the material. High temperature (>1250 °C) and long reaction duration led to a high C^* SiC conversion but with a relatively low surface area (20–25 m² · g^–1) due to sintering via the surface diffusion phenomenon. The combination of a lower reaction temperature (1200 °C), longer reaction duration (15 h) and high (Si + SiO₂)/C^* weight ratio allowed SiC to be obtained with a surface area of around 50 m² · g^–1, which can be used as a support material for heterogeneous catalysis.