1,816 research outputs found
Quantitative analysis of aircraft multispectral-scanner data and mapping of water-quality parameters in the James River in Virginia
Statistical analysis techniques were applied to develop quantitative relationships between in situ river measurements and the remotely sensed data that were obtained over the James River in Virginia on 28 May 1974. The remotely sensed data were collected with a multispectral scanner and with photographs taken from an aircraft platform. Concentration differences among water quality parameters such as suspended sediment, chlorophyll a, and nutrients indicated significant spectral variations. Calibrated equations from the multiple regression analysis were used to develop maps that indicated the quantitative distributions of water quality parameters and the dispersion characteristics of a pollutant plume entering the turbid river system. Results from further analyses that use only three preselected multispectral scanner bands of data indicated that regression coefficients and standard errors of estimate were not appreciably degraded compared with results from the 10-band analysis
Conduction Mechanism in a Molecular Hydrogen Contact
We present first principles calculations for the conductance of a hydrogen
molecule bridging a pair of Pt electrodes. The transmission function has a wide
plateau with T~1 which extends across the Fermi level and indicates the
existence of a single, robust conductance channel with nearly perfect
transmission. Through a detailed Wannier function analysis we show that the H2
bonding state is not involved in the transport and that the plateau forms due
to strong hybridization between the H2 anti-bonding state and states on the
adjacent Pt atoms. The Wannier functions furthermore allow us to derive a
resonant-level model for the system with all parameters determined from the
fully self-consistent Kohn-Sham Hamiltonian.Comment: 5 pages, 4 figure
Isolation and initial characterization of microvascular endothelial cells derived from the retoorbital connective tissue of patients with Graves ophthalmopathy
A Genomic Point Mutation in the Extracellular Domain of the Thyrotropin Receptor in Patients with Graves’ Ophthalmopathy
Orbital and pretibial fibroblasts are targets of autoimmune attack in Graves' ophthalmopathy (GO) and pretibial dermopathy (PTD). The fibroblast autoantigen involved in these peripheral manifestations of Graves' disease and the reason for the association of GO and PTD with hyperthyroidism are unknown. RNA encoding the full-length extracellular domain of the TSH receptor has been demonstrated in orbital and dermal fibroblasts from patients with GO and normal subjects, suggesting a possible antigenic link between fibroblasts and thyrocytes. RNA was isolated from cultured orbital, pretibial, and abdominal fibroblasts obtained from patients with severe GO (n = 22) and normal subjects (n = 5). RNA was reverse transcribed, and the resulting cDNA was amplified by the polymerase chain reaction, using primers spanning overlapping regions of the entire extracellular domain of the TSH receptor. Nucleotide sequence analysis showed an A for C substitution in the first position of codon 52 in 2 of the patients, both of whom had GO, PTD, and acropachy. Genomic DNA isolated from the 2 affected patients, and not from an additional 12 normal subjects, revealed the codon 52 mutation by direct sequencing and AciI restriction enzyme digestions. In conclusion, we have demonstrated the presence of a genomic point mutation, leading to a threonine for proline amino acid shift in the predicted peptide, in the extracellular domain of the TSH receptor in two patients with severe GO, PTD, acropachy, and high thyroid-stimulating immunoglobulin levels. RNA encoding this mutant product was demonstrated in the fibroblasts of these patients. We suggest that the TSH receptor may be an important fibroblast autoantigen in GO and PTD, and that this mutant form of the receptor may have unique immunogenic properties
Sourcing Specialised Skilled Labour in the Global Arena: A Change in the Way We View Work in Australia?
This article presents a newly developed research agenda to explore the increased needs of resource-rich regions in terms of sourcing industry-specific skilled labour. The article begins with a conceptual framework that maps the human resource management issues that are being magnified by the resources boom in Australia. The paper focuses on one of the five key thematic are as encompassed within the framework—labour global mobility. The difficulty in sourcing specialised skilled labour at this time indicates a major paradigm shift that is challenging long-held beliefs and constructs related to the nature of work in Australia with specialised skilled migrant workers actively sourced to fill positions in resources firms. After reviewing the international literature, we explore labour-sourcing practices as a response to dealing with skill shortages in the labour demand and supply of Australia’s resource-rich regions. This is followed by a discussion on how these practices have progressed in regional Queensland and Western Australia
Supply chains and responsibility for OHS management in the Western Australian resources sector
Purpose - The purpose of this paper is to analyse human resource supply chains and the responsibility of occupational health and safety (OHS) management using Australian evidence from two unrelated research studies in the resources sector. Design/methodology/approach - The analysis is based on additional findings from the research projects using qualitative case study methodologies. The paper draws on interviews with the underground mining manager in study 1 and the OHS manager in study 2, together with current literature on supply chains and OHS responsibility in Australia. Findings - The paper uses examples drawn from two research studies conducted in the resources sector in 2011 to present the notion that there has been a shift in responsibility and management of OHS from the top of the supply chain to the bottom. Research limitations/implications - The paper draws on two unrelated studies that investigated different issues in OHS management. There is a need to undertake specific research to confirm the argument that suggests that the OHS management systems are improving for the bottom of the human resources supply chain in the resources sector. Practical implications - Findings suggest that in the middle tier resources sector the bottom of the human resources supply chains have robust OHS management systems and induction training, contrary to the weakening of OHS management in typical supply chains in other sectors. Originality/value - Unlike manufacturing, healthcare, the public sector and transport, there is little research conducted in the resources sector researching supply chains and OHS management. This paper provides limited evidence of a differing picture in the resources sector than other industries; however, it argues that further studies should be conducted
Segregation of acid plume pixels from background water pixels, signatures of background water and dispersed acid plumes, and implications for calculation of iron concentration in dense plumes
Two files of data, obtained with a modular multiband scanner, for an acid waste dump into ocean water, were analyzed intensively. Signatures were derived for background water at different levels of effective sunlight intensity, and for different iron concentrations in the dispersed plume from the dump. The effect of increased sunlight intensity on the calculated iron concentration was found to be relatively important at low iron concentrations and relatively unimportant at high values of iron concentration in dispersed plumes. It was concluded that the basic equation for iron concentration is not applicable to dense plumes, particularly because lower values are indicated at the very core of the plume, than in the surrounding sheath, whereas radiances increase consistently from background water to dispersed plume to inner sheath to innermost core. It was likewise concluded that in the dense plume the iron concentration would probably best be measured by the higher wave length radiances, although the suitable relationship remains unknown
Tissue eosinophilia and eosinophil degranulation in Riedel's invasive fibrous thyroiditis.
The etiology of Riedel's invasive fibrous thyroiditis (IFT) has remained obscure. This rare disorder has been confused in the past with the more common fibrous variant of Hashimoto's disease. The typical histological features of IFT, in particular the presence of an invasive fibrosclerotic process in conjunction with a prominent chronic inflammatory infiltrate, suggest that the release of fibrogenic cytokines and other factors from these cellular infiltrates may play an important role in the pathogenesis of this condition. Our observations in routinely processed tissue sections obtained from patients with documented IFT of striking tissue eosinophilia led us to hypothesize that eosinophils and their products may play a role in the evolution of this disease. Immunofluorescence staining with affinity-purified polyclonal rabbit antibody directed against human eosinophil granule major basic protein revealed marked tissue eosinophilia and abundant extracellular deposition of major basic protein in all specimens from 16 patients with IFT. By contrast, only occasional eosinophils and no extracellular major basic protein were detected in control thyroid tissues obtained from patients with multinodular goiter, Graves' disease, Hashimoto's disease, and normal thyroid tissue. The presence of marked eosinophil infiltration and extracellular major basic protein deposition in IFT and other associated fibrosclerotic conditions suggests a role for eosinophils and their products in propagating the fibrogenesis seen in IFT
Partly Occupied Wannier Functions
We introduce a scheme for constructing partly occupied, maximally localized
Wannier functions (WFs) for both molecular and periodic systems. Compared to
the traditional occupied WFs the partly occupied WFs posses improved symmetry
and localization properties achieved through a bonding-antibonding closing
procedure. We demonstrate the equivalence between bonding-antibonding closure
and the minimization of the average spread of the WFs in the case of a benzene
molecule and a linear chain of Pt atoms. The general applicability of the
method is demonstrated through the calculation of WFs for a metallic system
with an impurity: a Pt wire with a hydrogen molecular bridge.Comment: 5 pages, 4 figure
Analysis of testbed airborne multispectral scanner data from Superflux II
A test bed aircraft multispectral scanner (TBAMS) was flown during the James Shelf, Plume Scan, and Chesapeake Bay missions as part of the Superflux 2 experiment. Excellent correlations were obtained between water sample measurements of chlorophyll and sediment and TBAMS radiance data. The three-band algorithms used were insensitive to aircraft altitude and varying atmospheric conditions. This was particularly fortunate due to the hazy conditions during most of the experiments. A contour map of sediment, and also chlorophyll, was derived for the Chesapeake Bay plume along the southern Virginia-Carolina coastline. A sediment maximum occurs about 5 nautical miles off the Virginia Beach coast with a chlorophyll maximum slightly shoreward of this. During the James Shelf mission, a thermal anomaly (or front) was encountered about 50 miles from the coast. There was a minor variation in chlorophyll and sediment across the boundary. During the Chesapeake Bay mission, the Sun elevation increased from 50 degrees to over 70 degrees, interfering with the generation of data products
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