Signature extension through space for northern landcover classification: A comparison of radiometric correction methods

Northern landcover mapping for climate change and carbon modeling requires greater detail than what is available from coarse resolution data. Mapping landcover with medium resolution data from Landsat presents challenges due to differences in time and space between scene acquisitions required for full coverage. These differences cause landcover signatures to vary due to haze, solar geometry and phenology, among other factors. One way to circumvent this problem is to have an image interpreter classify each scene independently, however, this is not an optimal solution in the north due to a lack of spatially extensive reference data and resources required to label scenes individually. Another possible approach is to stabilize signatures in space and time so that they may be extracted from one scene and extended to others, thereby reducing the amount of reference data and user input required for mapping large areas. A radiometric normalization approach was developed that exploits the high temporal frequency with which coarse resolution data are acquired and the high spatial frequency of medium resolution data. The current paper compares this radiometric correction methodology with an established absolute calibration methodology for signature extension for landcover classification and explores factors that affect extension performance to recommend how and when signature extension can be applied. Overall, the new normalization method produced better extension and classification results than absolute calibration. Results also showed that extension performance was affected more by geographical distance than by differences in anniversary dates between acquisitions for the range of data examined. Geographical distance in the north-south direction leads to poorer extension performance than distance in the east-west direction due in part to differences in vegetation composition assigned the same class label in the latitudinal direction. While extension performance was somewhat variable and in some cases did not produce a best classification result by itself, it provided an initial best guess of landcover that can subsequently be refined by an expert image interpreter.     

Enhancing the selenium content of bovine milk through alteration of the form and concentration of selenium in the diet of the dairy cow

Since estimated dietary selenium intake in the UK has declined steadily from around 60 µg day^?1 in 1975 to 34 µg day^?1 in 1997, there is a need to increase selenium intake from staple foods such as milk and milk products. An experiment was therefore done to investigate the relationship between dietary source and concentration of selenium and the selenium content of bovine milk. In a 3 × 3 factorial design, 90 mid‐lactation Holstein dairy cows were supplemented over 8 weeks with either sodium selenite (S), a chelated selenium product (Selenium Metasolate?) (C) or a selenium yeast (Sel‐Plex?) (Y) at three different dietary inclusion levels of 0.38 (L), 0.76 (M) and 1.14 (H) mg kg^?1 dry matter (DM). Significant increases in milk selenium concentration were observed for all three sources with increasing inclusion level in the diet, but Y gave a much greater response (up to +65 µg l^?1) than the other two sources of selenium (S and C up to +4 and +6 µg l^?1 respectively). The Y source also resulted in a substantially higher apparent efficiency of transfer of selenium from diet to milk than S or C. Feeding Y at the lowest dietary concentration, and thus within the maximum level permitted under EU regulations, resulted in milk with a selenium concentration of 28 µg l^?1. If the selenium concentration of milk in the UK was increased to this value, it would, at current consumption rates, provide an extra 8.7 µg selenium day^?1, or 11 and 14% of daily recommended national intake for men and women respectively. Copyright © 2004 Society of Chemical Industry     

Hydrothermal Synthesis of Pollucite (CsAlSi2O6) Powders

Pollucite (CsAlSi₂O₆) powders were produced by hydrothermal synthesis from relatively inexpensive precursors. The pollucite powders were comprised of polycrystalline particles with dimensions of hundreds of nanometers consisting of 25-75 nm crystallites. The polycrystalline particles were near stoichiometric composition. The pollucite powders were mixed with a poly(ethylene glycol) binder, pressed into disks, and sintered at temperatures from 1450° to 1550°C for 10 h. The resulting sintered ceramics had densities >80% of theoretical density and, in the best case, >97% of theoretical density.     

Anionic Ring-Opening Polymerization (ROP) of a Phosphorus-Bridged [1]Ferrocenophane Initiated by Living Polystyrene and Polyisoprene: Synthesis of Novel Organic–Poly(ferrocenylphosphine) Block Copolymers

The novel block copolymers, polystyrene-b-poly(ferrocenylphosphine) and polyisoprene-b-poly(ferrocenylphosphine), were synthesized by anionic polymerization, utilizing the living organic anions to initiate the ring-opening polymerization of a phosphorus-bridged [1]ferrocenophane. The resulting block copolymers possess narrow polydispersities and have potentially coordinating phosphorus sites in the polymer backbone. These materials are of interest as precursors to metallized self-assembled nanoscale architectures.     

Action of Extracts of Apiaceae on Feeding Behavior and Neurophysiology of the Field Slug Deroceras reticulatum

A systematic examination was made of the plant family Apiaceae (Umbelliferae) in which extracts of 33 species, representing 32 genera, were screened for antifeedant activity against the field slug Deroceras reticulatum by using an electrophysiological recording assay. In this assay, the olfactory sensory epithelium of the posterior tentacle of the slug was exposed to volatile components of the plant extracts presented in an airstream, and any subsequent activity of the olfactory nerve was recorded. Extracts of 22 species elicited a range of nervous activity in the preparation. A feeding bioassay was used to measure any change in consumption when extracts were added to a standard food. Statistical analysis of data obtained from both electrophysiological traces and the feeding bioassays identified extracts of Petroselinum crispum, Conium maculatum, and Coriandrum sativum as being the most neuroactive as well as the most antifeedant.     

Adhesion to textile fibres and fabrics

The production of textile fibres and the end-uses for textile-based materials continue to expand each year as the globalisation of the textile and clothing industries takes place. There is a wide range of natural and manufactured fibres available, but satisfactory adhesion to fibres, yarns and fabrics depends upon the nature of the fibre surface, the presence of natural or added impurities, and the effects of physical and chemical treatments. For aesthetic reasons, many textile materials are bleached, dyed and/or printed, and chemical finishing treatments are widely used in order to upgrade the fabric performance. Such treatments may modify the fibre surface energy, and the wetting and spreading processes, thereby creating difficulties in obtaining satisfactory adhesion to textile materials that are flexible, and may be moulded, bonded, coated or laminated. This paper will address some of the problem areas in relation to adhesion to fibres and fabrics, with reference also to problems that may be experienced in practice. Satisfactory adhesion to fibres and fabrics may be obtained when the material is dry, but failure of the adhesive joints may occur during aftercare treatments, e.g. washing and dry cleaning treatments.     

Poly(4-vinyltriphenylamine): synthesis and application as a hole transport layer in light-emitting diodes

Summary An efficient synthesis of 4-vinyltriphenylamine has been developed. This monomer has been polymerised using both anionic and free radical initiators to provide polymers suitable for casting films from solution. Light emitting diodes have been fabricated using this polymer as a hole transport layer (HTL). Comparable devices have been fabricated using evaporated triphenylamine or N,N'-diphenyl-N,N'-ditolylbenzidine as the HTL. Devices with the polymeric HTL display a greater brightness than those with the evaporated layers. Received: 24 September 1998/Revised version: 16 December 1998/Accepted: 16 December 1998     

Ultrasonic preparation of mesoporous silica using pyridinium ionic liquid

Mesoporous silica matrices have been prepared via classic acid catalyzed and sono-catalyzed sol-gel routes. Tetramethoxysilan (TMOS) and methyl-trimethoxysilane (MTMS) were used as silica precursors, and N-butyl-3-methylpyridinium tetrafluoroborate ([bmPy][BF₄]) was employed as co-solvent and pore template. The ionic liquid (IL) to silica mole ratio was varied between 0.007 and 0.07. Nitrogen adsorption-desorption and small-angle neutron scattering measurements were used to characterize the obtained materials. The ionic liquid played the role of catalyst that affected the formation of the primary xerogel particles, and changed the porosity of the materials. Ultrasound treatment resulted in microstructure change on the level of the colloid particle aggregates. In comparison with IL containing xerogels, the IL containing sonogels show increased pore diameter, bigger pore volumes and diminished surface areas.