Applications of analytical electron microscopy to guide the design of boron carbide

Compositional analysis of boron carbide on nanometer length scales to examine or interpret atomic mechanisms, for example, solid-state amorphization or grain-boundary segregation, is challenging. This work reviews advancements in high-resolution microanalysis to characterize multiple generations of boron carbide. First, ζ-factor microanalysis will be introduced as a powerful (scanning) transmission electron microscopy ((S)TEM) analytical framework to accurately characterize boron carbide. Three case studies involving the application of ζ-factor microanalysis will then be presented: (1) accurate stoichiometry determination of B-doped boron carbide using ζ-factor microanalysis and electron energy loss spectroscopy, (2) normalized quantification of silicon grain-boundary segregation in Si-doped boron carbide, and (3) calibration of a scanning electron microscope X-ray energy-dispersive spectroscopy (XEDS) system to measure compositional homogeneity differences of B/Si-doped arc-melted boron carbides in the as-melted and annealed conditions. Overall, the improvement and application of advanced analytical tools have helped better understand processing–microstructure–property relationships and successfully manufacture high-performance ceramics.     

Relay and sequential cropping corn with winter oilseed crops in northern climates

Nutrient Cycling in Agroecosystems - Winter oilseed crops camelina [Camelina sativa (L.) Crantz] and field pennycress (Thlaspi arvense L.) are potential candidates for diversifying the...     

Differences between oculomotor and perceptual artifacts for temporally limited head mounted displays

We used perceptual and oculomotor measures to understand the negative impacts of low (phantom array) and high (motion blur) duty cycles with a high‐speed, AR‐likehead‐mounted display prototype. We observed large intersubject variability for the detection of phantom array artifacts but a highly consistent and systematic effect on saccadic eye movement targeting during low duty cycle presentations. This adverse effect on saccade endpoints was also related to an increased error rate in a perceptual discrimination task, showing a direct effect of display duty cycle on the perceptual quality. For high duty cycles, the probability of detecting motion blur increased during head movements, and this effect was elevated at lower refresh rates. We did not find an impact of the temporal display characteristics on compensatory eye movements during head motion (e.g., VOR). Together, our results allow us to quantify the tradeoff of different negative spatiotemporal impacts of user movements and make subsequent recommendations for optimized temporal HMD parameters.     

Retracted: Analysis of blade fragment risk at a wind energy facility

The above article, published online on 6 April 2018 in Wiley Online Library ( wileyonlinelibrary.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Prof. Simon Watson and John Wiley and Sons Ltd. The retraction has been agreed due to an error in the conclusion, which used the analysis of NREL's wind site for evaluation of wind turbine setbacks in general. The assumptions and results do not apply to commercial wind energy sites, as the conclusion suggests, and are therefore not suitable for setback recommendations in other locations.     

Economic effects of regulating the seismic strengthening of older buildings

The marked increase in the awareness of earthquake risk following the Canterbury earthquakes in New Zealand offered a unique opportunity to investigate the economic effect of disaster-mitigation regulations on the commercial building stock. A difference-in-differences (DD) framework was used to determine whether earthquake risk has been capitalized into the property prices of buildings constructed prior to 1976, as a response to the national policy requiring assessment and strengthening (or demolition) of the existing earthquake-prone building stock. A negative externality is found in the policy announcement on affected (pre-1970s) office and retail buildings which caused office buildings to suffer a 12.5% stigma discount. However, retail properties were less impacted suffering a 2.3% stigma loss. The value of the commercial building stock has been affected by the policy. These findings provide policy-makers with timely evidence as to the economic effects of New Zealand’s earthquake-prone buildings policy. Facing losses in property value and financial responsibility for retrofitting their assets, building owners will be looking for a workable set of regulatory and non-regulatory incentives to encourage disaster risk management and protect the built environment.     

Forest governance and REDD+ in Central Africa: towards a participatory model to increase stakeholder involvement in carbon markets

Forests play a significant role in the global carbon budget, and can help to mitigate climate change impacts. Tropical forests which experience high rates of deforestation and forest degradation are particularly important, as they are the most active in winter. Based on academic research into global environmental policies in Central Africa, this study finds that REDD+ policies can succeed when there is a carbon market mechanism that increases participation by developing countries, with better integration of forest management and community forestry. Incentives should be based on an appropriate baseline, accurate carbon stocks and fluxes estimation, a suitable silvicultural system and regular monitoring.     

低调的绿洲 奥斯汀Carpenter酒店

正美国设计事务所Specht Architects在奥斯汀市中心翻新并扩建了一座20世纪40年代的旧地标建筑,将其改造成一座全新的精品酒店。建筑坐落在一片被精心保护的传统山核桃树林中,它曾是该市Carpenters'Local 1266工会的旧址。故而酒店取名为"Carpenter Hotel",也是为了呼应建筑曾经的历史。在酒店的整体设计中,建筑师摒弃重建历史风格或追逐建筑潮流的方式,而是选择将所有新旧部分融合为一幅更有意义的城市拼贴画。酒店采用混凝土框架结构,以砖和混     

Allele-Specific Inhibition of Histone Demethylases

Histone demethylases play a critical role in mammalian gene expression by removing methyl groups from lysine residues in degree- and site-specific manner. To specifically interrogate members and isoforms of this class of enzymes, we have developed demethylase variants with an expanded active site. The mutant enzymes are capable of performing lysine demethylation with wild-type proficiency, but are sensitive to inhibition by cofactor-competitive molecules embellished with a complementary steric “bump”. The selected inhibitors show more than 20-fold selectivity over the wild-type demethylase, thus overcoming issues typical to pharmacological and genetic approaches. The mutant–inhibitor pairs are shown to act on a physiologically relevant full-length substrate. By engineering a conserved amino acid to achieve member-specific perturbation, this study provides a general approach for studying histone demethylases in diverse cellular processes.