The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
J. Vaun Mcarthur - One of the best experts on this subject based on the ideXlab platform.
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Trace Element accumulation in lotic dragonfly nymphs: Genus matters.
PloS one, 2017Co-Authors: Dean E. Fletcher, Angela H. Lindell, Garrett K. Stillings, Susan A. Blas, J. Vaun McarthurAbstract:Constituents of coal combustion waste (CCW) expose aquatic organisms to complex mixtures of potentially toxic metals and metalloids. Multi-Element Trace Element analyses were used to distinguish patterns of accumulation among 8 genera of dragonfly nymphs collected from two sites on a CCW contaminated coastal plain stream. Dragonfly nymphs are exceptional for comparing Trace Element accumulation in syntopic macroinvertebrates that are all predators within the same order (Odonata) and suborder (Anisoptera), but differ vastly in habitat use and body form. Sixteen Trace Element (Be, V, Cr, Ni, Cu, Zn, As, Se, Sr, Cd, Sb, Cs, Ba, Hg, Tl, and Pb) were analyzed and trophic position and basal carbon sources assessed with stable isotope analyses (C and N). Trophic positions varied within relatively narrow ranges. Size did not appear to influence trophic position. Trophic position rarely influenced Trace Element accumulation within genera and did not consistently correlate with accumulation among genera. Patterns between δ13C and Trace Element accumulation were generally driven by differences between sites. An increase in Trace Element accumulation was associated with a divergence of carbon sources between sites in two genera. Higher Trace Element concentrations tended to accumulate in nymphs from the upstream site, closer to contaminant sources. Influences of factors such as body form and habitat use appeared more influential on Trace Element accumulation than phylogeny for several Elements (Ni, Ba, Sr, V, Be, Cd, and Cr) as higher concentrations accumulated in sprawler and the climber-sprawler genera, irrespective of family. In contrast, As and Se accumulated variably higher in burrowers, but accumulation in sprawlers differed between sites. Greater variation between genera than within genera suggests genus as an acceptable unit of comparison in dragonfly nymphs. Overall, taxonomic differences in Trace Element accumulation can be substantial, often exceeding variation between sites. Our results underscore the Element and taxa specific nature of Trace Element accumulation, but we provide evidence of accumulation of some Trace Elements differing among dragonflies that differ in body form and utilize different sub-habitats within a stream reach.
T. W. Graham - One of the best experts on this subject based on the ideXlab platform.
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Trace Element deficiencies in cattle.
The Veterinary clinics of North America. Food animal practice, 1991Co-Authors: T. W. GrahamAbstract:Deficiency of cobalt, copper, iron, iodine, manganese, selenium, or zinc can cause a reduction in production. Reduced production occurs most commonly when a deficiency corresponds to the phases of growth, reproduction, or lactation. Because of environmental, nutrient, disease, genetic, and drug interactions, deficiencies of single or multiple Elements can occur even when the levels recommended by the National Research Council for these nutrients are being fed. Additionally, random supplementation of Trace Elements above National Research Council recommendations is not justified because of the negative interaction among nutrients and potential toxicosis. Evaluation of Trace Element status can be difficult because many disease states will alter blood analytes used to evaluate nutrient adequacy. Proper dietary and animal evaluation, as well as response to supplementation, are necessary before diagnosing a Trace Element deficiency.
Pentti Hölttä - One of the best experts on this subject based on the ideXlab platform.
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Trace Element partitioning in the granulite facies
Contributions to Mineralogy and Petrology, 2010Co-Authors: Franziska Nehring, Stephen F. Foley, Pentti HölttäAbstract:Analyses of Trace Elements in the mineral phases of granulites provide important information about the Trace Element distribution in the lower crust. Since granulites are often considered residues of partial melting processes, Trace Element characteristics of their mineral phases may record mineral/melt equilibria thus giving an opportunity to understand the nature and composition of melts in the lower continental crust. This study provides an extensive set of mineral Trace Element data obtained by LA-ICP-MS analyses of mafic and intermediate granulites from Central Finland. Mass balance calculations using the analytical data indicate a pronounced contribution of the accessory minerals apatite for the REE and ilmenite for the HFSE. Coherent mineral/mineral ratios between samples point to a close approach to equilibrium except for minerals intergrown with garnet porphyroblasts. Mineral Trace Element data were used for the formulation of a set of D ^mineral/melt partition coefficients that is applicable for Trace Element modelling under lower crustal conditions. D ^mineral/melt were derived by the application of predictive models and using observed constant mineral/mineral ratios. The comparison of the calculated D ^mineral/melt with experimental data as well as the relationship between mineral Trace Element contents and a leucosome with a composition close to an equilibrium melt provides additional constraints on mineral/melt partitioning. The D values derived in this study are broadly similar to magmatic partition coefficients for intermediate melt compositions. They provide a first coherent set of D values for Sc, V, Cr and Ni between clinopyroxene, amphibole, garnet, orthopyroxene, ilmenite and melt. In addition, they emphasize the strong impact that ilmenite exerts on the distribution of Nb and Ta.
Dean E. Fletcher - One of the best experts on this subject based on the ideXlab platform.
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Trace Element accumulation in lotic dragonfly nymphs: Genus matters.
PloS one, 2017Co-Authors: Dean E. Fletcher, Angela H. Lindell, Garrett K. Stillings, Susan A. Blas, J. Vaun McarthurAbstract:Constituents of coal combustion waste (CCW) expose aquatic organisms to complex mixtures of potentially toxic metals and metalloids. Multi-Element Trace Element analyses were used to distinguish patterns of accumulation among 8 genera of dragonfly nymphs collected from two sites on a CCW contaminated coastal plain stream. Dragonfly nymphs are exceptional for comparing Trace Element accumulation in syntopic macroinvertebrates that are all predators within the same order (Odonata) and suborder (Anisoptera), but differ vastly in habitat use and body form. Sixteen Trace Element (Be, V, Cr, Ni, Cu, Zn, As, Se, Sr, Cd, Sb, Cs, Ba, Hg, Tl, and Pb) were analyzed and trophic position and basal carbon sources assessed with stable isotope analyses (C and N). Trophic positions varied within relatively narrow ranges. Size did not appear to influence trophic position. Trophic position rarely influenced Trace Element accumulation within genera and did not consistently correlate with accumulation among genera. Patterns between δ13C and Trace Element accumulation were generally driven by differences between sites. An increase in Trace Element accumulation was associated with a divergence of carbon sources between sites in two genera. Higher Trace Element concentrations tended to accumulate in nymphs from the upstream site, closer to contaminant sources. Influences of factors such as body form and habitat use appeared more influential on Trace Element accumulation than phylogeny for several Elements (Ni, Ba, Sr, V, Be, Cd, and Cr) as higher concentrations accumulated in sprawler and the climber-sprawler genera, irrespective of family. In contrast, As and Se accumulated variably higher in burrowers, but accumulation in sprawlers differed between sites. Greater variation between genera than within genera suggests genus as an acceptable unit of comparison in dragonfly nymphs. Overall, taxonomic differences in Trace Element accumulation can be substantial, often exceeding variation between sites. Our results underscore the Element and taxa specific nature of Trace Element accumulation, but we provide evidence of accumulation of some Trace Elements differing among dragonflies that differ in body form and utilize different sub-habitats within a stream reach.
Brian A. Wharton - One of the best experts on this subject based on the ideXlab platform.
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Trace Element deficiency in man: classifications and methods of assessment
Food Chemistry, 1992Co-Authors: Brian A. WhartonAbstract:Abstract Trace Element deficiencies may be classified in many ways, for example from the viewpoints of developmental biology, geography, biochemistry and clinical medicine. While the major tool of Trace Element assessment will be analytical biochemistry this will be most effective when used in combination with other disciplines. Microbiology, medical mathematics and behavioural science are given as examples of other disciplines which contribute to our understanding of the pathophysiological, public health, and clinical significance of Trace Element deficiency.
