AVHRR channel selection for land cover classification

Mapping land cover of large regions often requires processing of satellite images collected from several time periods at many spectral wavelength channels. However, manipulating and processing large amounts of image data increases the complexity and time, and hence the cost, that it takes to produce a land cover map. Very few studies have evaluated the importance of individual Advanced Very High Resolution Radiometer (AVHRR) channels for discriminating cover types, especially the thermal channels (channels 3, 4 and 5). Studies rarely perform a multi-year analysis to determine the impact of inter-annual variability on the classification results. We evaluated 5 years of AVHRR data using combinations of the original AVHRR spectral channels (1-5) to determine which channels are most important for cover type discrimination, yet stabilize inter-annual variability. Particular attention was placed on the channels in the thermal portion of the spectrum. Fourteen cover types over the entire state of Colorado were evaluated using a supervised classification approach on all two-, three-, four- and five-channel combinations for seven AVHRR biweekly composite datasets covering the entire growing season for each of 5 years. Results show that all three of the major portions of the electromagnetic spectrum represented by the AVHRR sensor are required to discriminate cover types effectively and stabilize inter-annual variability. Of the two-channel combinations, channels 1 (red visible) and 2 (near-infrared) had, by far, the highest average overall accuracy (72.2%), yet the inter-annual classification accuracies were highly variable. Including a thermal channel (channel 4) significantly increased the average overall classification accuracy by 5.5% and stabilized interannual variability. Each of the thermal channels gave similar classification accuracies; however, because of the problems in consistently interpreting channel 3 data, either channel 4 or 5 was found to be a more appropriate choice. Substituting the thermal channel with a single elevation layer resulted in equivalent classification accuracies and inter-annual variability.     

Electronic structure of Li2O2 {0001} surfaces

The surface properties of the Li₂O₂ discharge phase are expected to impact strongly the capacity, rate capability, and rechargeability of Li-oxygen batteries. Prior calculations have suggested that the presence of half-metallic surface states in Li₂O₂ may mitigate electrical passivation resulting from the growth of Li₂O₂, which is a bulk insulator. Here we revisit the electronic structure of bulk Li₂O₂ and the dominant Li₂O₂ {0001} surface by comparing results obtained with the PBE GGA functional, the HSE06 hybrid functional, and quasiparticle GW methods. Our results suggest that the bulk band gap lies between the value predicted by the G₀W₀ method, 5.15 eV, and the value predicted by the self-consistent quasiparticle GW (scGW) approximation, 6.37 eV. The PBE, HSE06, and scGW methods agree that the most stable surface, an oxygen-rich {0001} termination, is indeed half-metallic. This result supports the notion that the electronic structure of surfaces may play an important role in understanding performance limitations in Li-oxygen batteries.     

Structural and chemical changes of thermally treated bone apatite

The thermal behaviour of the animal by-product meat and bone meal (MBM) has been investigated in order to assess how it is affected structurally and chemically by incineration. Initially composed of intergrown collagen and hydroxyapatite (HAP), combustion of the organic component is complete by 650 °C, with most mass loss (50–55%) occurring by 500 °C. No original proteins were detected in samples heated at 400 °C or above. Combustion of collagen is accompanied by an increase in HAP mean crystallite size at temperatures greater than 400 °C, from 10 nm to a constant value of 120 nm at 800 °C or more. Newly formed crystalline phases appear beyond 400 °C, and include β-tricalcium phosphate, NaCaPO₄, halite (NaCl) and sylvite (KCl). Crystallite thickness as judged by small angle X-ray scattering (SAXS) increases from 2 nm (25–400 °C) to 8–9 nm very rapidly at 550 °C, and then gradually increases to approximately 10 nm. The original texture of HAP within a collagen matrix is progressively lost, producing a porous HAP dominated solid at 700 °C, and a very low porosity sintered HAP product at 900 °C.     

Prediction of environmental stress cracking resistance in linear low density polyethylenes

Recently it has been shown that the strain hardening modulus (G_p) at 80°C can be used to predict the environmental stress cracking (ESC) resistance of polyethylenes. The advantage of using strain hardening to determine ESC resistance is that the data may be obtained relatively easily and quickly using simple tensile test equipment. In this article, the strain hardening modulus has been used to predict the ESC resistance of three grades of linear low‐density polyethylene. Unlike in the previous research, the measurements were conducted at room temperature enabling tests to be performed without the need of a temperature‐controlled oven. This was achieved by reducing the strain rate to increase the sensitivity of the technique and increasing the thickness of the specimens to improve the repeatability. The strain hardening modulus data were found to correlate well with the ESC results obtained from long‐term full notch creep tests and are consistent with the known molecular structure of the polyethylene grades. POLYM. ENG. SCI., 2008. © 2007 Society of Plastics Engineers     

Activity-Based Costing as a Tool for Process Improvement Evaluations

Many corporate processes common to the design and construction of major engineered projects are composed of individual activities that are variable by nature. Additionally, the process itself may have a high degree of variability, meaning that certain activities may or may not actually be performed in a given pass through the process. We may ascribe to such activities a “probability of occurrence.” True modeling of real world processes will often require that we describe the process as having activities with stochastic durations, each linked together in a precedence logic that itself is variable and subject to uncertainty or chance. If corporate resources, such as labor, material, and equipment, are required to perform the individual activities, then an activity-based costing technique must be developed that can accommodate the inherent variability in a process if actual costs are to be accurately predicted. If process cycle time and process cost per cycle can be accurately predicted for complex, highly variable processes, companies are in a much better position to determine how proposed corporate initiatives for process improvement might actually impact overall process performance. This technique has application across a wide number of disciplines including design, construction, and administrative processes.     

The Future of Work — Understanding the Role of Technology

The twentieth century has seen many major changes in the nature of work and its role in people's lives. Organisational change has been driven by dramatic changes in the economic and social climate during this period. This is happening at an increasingly rapid rate as we enter the new century. This paper reviews current trends in the world of work. It will focus on the increasing dispersal of the workforce and how communications technology makes possible working arrangements which were previously unthinkable. BT aims to design future products and services which address the real needs of people working in the future. This is being tackled by building up a fundamental understanding of the issues affecting relationships between individuals and organisations, and the potential impact of computer-mediated communications technology on these relationships. This paper focuses on the work that has been done to understand the issue of trust, a key element of the way that people relate to each other at work. This research has culminated in the definition of a theoretical model of trust which has been used to analyse two particular practical studies — a long-term flexible working trial and a series of trials with innovative desktop conferencing tools.     

Structure–function relationships of fullerene esters in polymer solar cells: unexpected structural effects on lifetime and efficiency

We report both transport measurements and spectroscopic data of polymer/fullerene blend photovoltaics using a small library of fullerene esters to correlate device properties with a range of functionality and structural diversity of the ester substituent. We observe that minor structural changes can lead to significant and surprising differences in device efficiency and lifetime. For example we have found that isomeric R‐groups in the fullerene ester‐based devices we have studied have dramatically different efficiencies. The characteristic lifetimes derived from both transport and spectroscopic measurements are generally comparable; however, some more rapid effects in specific fullerene esters are not observed spectroscopically. It is apparent from our results that each fullerene derivative requires re‐optimization to reveal the best device performance. Furthermore we conclude that a library approach is essential for evaluating the effects of structural differences in the constituent molecules and serves as important device optimization method that is not being currently employed in photovoltaic investigations. Copyright © 2015 John Wiley & Sons, Ltd.     

Advances and Perspectives in Tissue Culture and Genetic Engineering of Cannabis

For a long time, Cannabis sativa has been used for therapeutic and industrial purposes. Due to its increasing demand in medicine, recreation, and industry, there is a dire need to apply new biotechnological tools to introduce new genotypes with desirable traits and enhanced secondary metabolite production. Micropropagation, conservation, cell suspension culture, hairy root culture, polyploidy manipulation, and Agrobacterium-mediated gene transformation have been studied and used in cannabis. However, some obstacles such as the low rate of transgenic plant regeneration and low efficiency of secondary metabolite production in hairy root culture and cell suspension culture have restricted the application of these approaches in cannabis. In the current review, in vitro culture and genetic engineering methods in cannabis along with other promising techniques such as morphogenic genes, new computational approaches, clustered regularly interspaced short palindromic repeats (CRISPR), CRISPR/Cas9-equipped Agrobacterium-mediated genome editing, and hairy root culture, that can help improve gene transformation and plant regeneration, as well as enhance secondary metabolite production, have been highlighted and discussed.     

Targeted Fluorination of a Nonsteroidal Anti‐inflammatory Drug to Prolong Metabolic Half‐Life

In drug design, one way of improving metabolic stability is to introduce fluorine at a metabolically labile site. In the early stages of drug design, identification of such sites is challenging, and a rapid method of assessing the effect of fluorination on a putative drug’s metabolic stability would be of clear benefit. One approach to this is to employ micro‐organisms that are established as models of drug metabolism in parallel with the synthesis of fluorinated drug analogues. In this study, we have used the filamentous fungus Cunninghamella elegans to identify the metabolically labile site of the nonsteroidal anti‐inflammatory drug flurbiprofen, to aid in the design of fluorinated derivatives that were subsequently synthesised. The effect of the additional fluorine substitution on cytochrome P450‐catalysed oxidation was then determined via incubation with the fungus, and demonstrated that fluorine substitution at the 4′‐position rendered the drug inactive to oxidative transformation, whereas substitution of fluorine at either 2′ or 3′ resulted in slower oxidation compared to the original drug. This approach to modulating the metabolic stability of a drug‐like compound is widely applicable and can be used to address metabolic issues of otherwise good lead compounds in drug development.