261 research outputs found
Soil and permafrost distribution, soil characterisation and soil vulnerability to human foot trampling, Wright Valley, Antarctica
Soils and shallow permafrost in Wright Valley, Antarctica were mapped at a scale of 1:50 000 to depict their spatial distribution, and sampled to determine the main drivers for the soil classification.
In the cold desert of Wright Valley the Gelisol order of Soil Taxonomy was used to classify the soils. Soils on younger surfaces, associated with Lower Wright Glacier, Upper Wright Glacier and alpine glaciers, contain massive ice within 100 cm of the soil surface and are classified as Glacic Haplorthels or Glacic Haploturbels where there is field evidence of cryoturbation. As a generalization, at either end of the valley, soil moisture recharge from moist coastal air masses (eastern end) and blowing snow drifts maintain the depth to permafrost in which ice-cement occurs at 70 cm, are classified as Salic or Typic Anhyorthels or, where there is field evidence of cryoturbation, Anhyturbels.
While mapping soils in Wright Valley, the distribution and nature of the shallow permafrost were also investigated. Three classes of permafrost were established to coincide with definitions or conditions within Soil Taxonomy viz: permafrost with ice-cement at 70 cm, and massive ice.
A definition for a petrosalic horizon is proposed based on the properties of a salic horizon and the indurated nature of petrocalcic/petrogypsic horizons. The horizon is likely to occur only in the cold desert climate zones of Antarctica.
A rapid method to determine soil vulnerability to human foot traffic was developed. As vulnerability is the product of disturbance and rehabilitation, the method is based on the disturbance of 10 foot prints at a site multiplied by a soil rehabilitation factor based on the soil weathering stage. Although fine-grained aeolian sands are easily disturbed they also rehabilitate rapidly in the windy conditions of Wright Valley. In contrast, old stable soils have a tight cobbly desert pavement with reddish desert varnish and often show less foot print disturbance. When cobbles are overturned, however, fresh rock with thick salt accumulations and without desert varnish is exposed. It takes much time for the desert varnish to re-establish.
The spatial distribution of Soil Taxonomy soil classes, nature of the permafrost and soil vulnerability to human traffic are presented as three separate maps at 1:50 000 scale and as live GIS files
Thiol-reactive analogues of galanthamine, codeine and morphine as potential probes to interrogate allosteric binding within nAChRs
Alkaloids including galanthamine (1) and codeine (2) are reported to be positive allosteric modulators of nicotinic acetylcholine receptors (nAChRs) but the binding sites responsible for this activity are not known with certainty. Analogues of galanthamine (1), codeine (2) and morphine (3) with reactivity towards cysteine thiols were synthesised including conjugated enone derivatives of the three alkaloids 4-6 and two chloro-alkane derivatives of codeine 7 and 8. The stability of the enones was deemed sufficient for use in buffered aqueous solutions and their reactivity towards thiols was assessed by determining the kinetics of reaction with a cysteine derivative. All three enone derivatives were of sufficient reactivity and stability to be used in covalent trapping, an extension of the substituted cysteine accessibility method (SCAM), to elucidate the allosteric binding sites of galanthamine and codeine at nAChRs
Soils of western Wright Valley, Antarctica
Western Wright Valley, from Wright Upper Glacier to the western end of the Dais, can be divided into three broad geomorphic regions: the elevated Labyrinth, the narrow Dais which is connected to the Labyrinth, and the North and South forks which are bifurcated by the Dais. Soil associations of Typic Haplorthels/Haploturbels with ice-cemented permafrost at 70 cm. They are developed in situ in strongly weathered drift with very low surface boulder frequency and occur on the upper erosion surface of the Labyrinth and on the Dais. Typic Anhyorthels also occur at lower elevation on sinuous and patchy Wright Upper III drift within the forks. Salic Aquorthels exist only in the South Fork marginal to Don Juan Pond, whereas Salic Haplorthels occur in low areas of both South and North forks where any water table is> 50 cm. Most soils within the study area have an alkaline pH dominated by Na+ and Cl- ions. The low salt accumulation within Haplorthels/Haploturbels may be due to limited depth of soil development and possibly leaching
A simple method for the small scale synthesis and solid-phase extraction purification of steroid sulfates
Steroid sulfates are a major class of steroid metabolite that are of growing importance in fields such as anti-doping analysis, the detection of residues in agricultural produce or medicine. Despite this, many steroid sulfate reference materials may have limited or no availability hampering the development of analytical methods. We report simple protocols for the rapid synthesis and purification of steroid sulfates that are suitable for adoption by analytical laboratories. Central to this approach is the use of solid-phase extraction (SPE) for purification, a technique routinely used for sample preparation in analytical laboratories around the world. The sulfate conjugates of sixteen steroid compounds encompassing a wide range of steroid substitution patterns and configurations are prepared, including the previously unreported sulfate conjugates of the designer steroids furazadrol (17β-hydroxyandrostan[2,3-d]isoxazole), isofurazadrol (17β-hydroxyandrostan[3,2-c]isoxazole) and trenazone (17β-hydroxyestra-4,9-dien-3-one). Structural characterization data, together with NMR and mass spectra are reported for all steroid sulfates, often for the first time. The scope of this approach for small scale synthesis is highlighted by the sulfation of 1μg of testosterone (17β-hydroxyandrost-4-en-3-one) as monitored by liquid chromatography-mass spectrometry (LCMS).We thank the Australian Research Council (LP120200444) for
financial support
Diastereoselective Osmium-catalyzed Vicinal Oxyamination of Acyclic Allylic Alcohol Derivatives
The osmium-catalyzed oxyamination of chiral acyclic allylic alcohol derivatives bearing mono- and 1,1-di-substituted double bonds with benzyl N-(4-tosyloxy)carbamate proceeds with high regioselectivity and moderate levels of diastereoselectivity favoring the anti product. The observed stereoselectivity shows a clear and systematic trend with anti:syn ratios increasing in line with the size of substituent at both the allylic stereocenter and double bond alpha-carbon. The stereoinduction is in accord with the sense of diastereoselectivity predicted by Kishi’s empirical rule and a previously reported transition state model for the osmium-catalyzed dihydroxylation of allylic alcohol derivatives. In contrast, allylic alcohol derivatives bearing trisubstituted double bonds show low or no reactivity in the oxyamination reaction affording the syn product in low yield in the cases examined.Directorate General of Higher Education Indonesia (DIKTI
A review of designer anabolic steroids in equine sports
In recent years, the potential for anabolic steroid abuse in equine sports has increased due to the growing availability of designer steroids. These compounds are readily accessible online in 'dietary' or 'nutritional' supplements and contain steroidal compounds which have never been tested or approved as veterinary agents. They typically have unusual structures or substitution and as a result may pass undetected through current anti-doping screening protocols, making them a significant concern for the integrity of the industry. Despite considerable focus in human sports, until recently there has been limited investigation into these compounds in equine systems. To effectively respond to the threat of designer steroids, a detailed understanding of their metabolism is needed to identify markers and metabolites arising from their misuse. A summary of the literature detailing the metabolism of these compounds in equine systems is presented with an aim to identify metabolites suitable for incorporation into screening protocols by anti-doping laboratories. The future of equine anti-doping research is likely to be guided by the incorporation of alternate testing matrices into routine screening, the improvement of in vitro technologies that can mimic in vivo equine metabolism, and the improvement of instrumentation or analytical methods that allow for the development of untargeted screening, and metabolomics approaches for use in anti-doping screening protocols. Copyright © 2016 John Wiley & Sons, Ltd.ARC Linkage Project LP120200444 – Strategies for the detection of designer steroids in racehorse
Use of video shadow for small group interaction awareness on a large interactive display surface
This paper reports work done as part of the Large Interactive Display Surface (LIDS) project at the University of Waikato. One application of the LIDS equipment is distributed meeting support. In this context large display surfaces are used as shared workspaces by people at collaborating sites. A meeting with start with a shared presentation document, typically and agenda document with summary and detail on agenda items as required. During the meeting, annotations with be made on the shared document, and new pages will be added with notes and drawings.
To prevent access collisions and generally mediate use of the shared space, mechanisms to provide awareness of actions of people at other sites are required. In our system a web camera is used to capture a low-resolution image of the person/people near the board on each side. Rather than transmit the image directly we computed a shadow/silhouette. The shadow is displayed behind other screen content. This provides awareness of position and impending write actions and allows intentional pointing to locations of the screen. It also has the advantage of being transmitted with low bandwidth, being relatively insensitive to low frame rates, and minimizing visual interference with substantive data being displayed on the screen
Archived U-Pb (zircon) dates from southern New Brunswick
U-Pb (zircon) ages for eight samples from southern New Brunswick were determined during the early 1990's as part of a regional mapping and correlation program. Although most of the dates have been subsequently quoted in the literature through personal communications, and some preliminary isochron diagrams have been incorporated in papers, the results have not been published in their entirety. The units sampled and best estimates for their ages are the Lobster Brook Formation (554 ± 6 Ma), Leavitts Head Formation (554 ± 3 Ma), Ragged Falls Suite (553 ± 2 Ma), Mosquito Lake Road Formation (514 ± 2 Ma, maximum age), Bayswater Formation (436 ± 3 Ma), Centreton Granite (437 ± 3 Ma), felsic dyke of North Head, Grand Manan Island (396+3/-2 Ma), and Lake George Cupola, Lake George Mine (414 ± 2 Ma).
RÉSUMÉ
Des datations au U-Pb (à partir de zircon) de huit échantillons du Sud du Nouveau-Brunswick avaient été réalisées au début des années 90 dans le cadre d'un programme régional de cartographie et de corrélation. Même si la majorité des dates ont subséquemment été citées dans de la documentation par le biais de communications personnelles et que certains schémas isochrones préliminaires ont été incorporés dans des communications, les résultats n'ont pas été publiés dans leur intégralité. Les unités échantillonnées et leur meilleurs âges estimatifs comprennent la Formation de Lobster Brook (554 ± 6 Ma), la Formation de Leavitts Head (554 ± 3 Ma), le cortège de Ragged Falls (553 ± 2 Ma), la Formation de Mosquito Lake Road (514 ± 2 Ma, âge maximal), la Formation de Bayswater (436 ± 3 Ma), le granite de Centreton (437 ± 3 Ma), le dyke felsique de North Head, dans l'île Grand Manan (396+3/-2 Ma), et la coupole du lac George, à la mine du lac George (414 ± 2 Ma).
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Mafic intrusions on Campobello Island: implications for New Brunswick - Maine correlations
Late Ordovician through Early Devonian units of the Passamaquoddy Bay area are interpreted to represent sequences that evolved in arc and back-arc environments. The main elements of the arc are exposed on Campobello Island and include a predominantly felsic volcanic sequence to the northeast, a sequence of intercalated turbidite and mafic volcanic rocks to the southwest, and matic dyke swarms throughout. Petrographic. geochemical, and 40Ar/39Ar studies of these rocks record episodic deformation and varying degrees of metamorphism up to lower amphibolite facies, and a protracted history of mafic magma injection from a similar source beginning in the Early Silurian. These features, combined with stratigraphic relationships and overall structural patterns, indicate a rapid transition from felsic- to mafic-dominated magmatism accompanied by radical changes in the depositional regime in the arc with time, and exposure of progressively deeper crustal levels towards the northeast within the arc.
Review of the assignment of other units in the Passamaquoddy Bay region to major tectonostratigraphic bells north of Campobello Island clarifies regional correlations and provides possible additional links to Neoproterozoic basement in the area.
RÉSUMÉ
Les unités de l'Ordovicien superieur au Dévonicn inférieur du secteur de la baie Passamaquoddy sont interprétées comme des unités représentatives de séquences ayant évolué dans des environnements d'arc et d'arriére-arc. Les principaux éléments de de l'arc affleurent sur l'ile Campobello et component une séquence principalcment volcanofelsique au nord-est. une sequence volcanomafique/turbiditique intercalée au sud-ouest et des groupes de filons mafiques un peu panout. Des études pétrographiques. géochimiques et 40Ar/39Ar de ces roches rélèvent une déformation épisodique et des degrés divers de métamorphisme jusqu'au faciès amphibolique infèrieur, ainsi que des antécédents prolongés d'injection de magma mafique d'une source similairc à partir du Silurien inferieur. Ces particulierités conjuguécs aux relations stratigraphiques et aux configurations slructurales générates, révèlent une transition rapide d'un magmatisme à prédominance mafique a un magmatisme à prédominance mafique accompagné de changements spectaculaires dans te régime de sédimentation à l'intérieur de l'are avec le temps, ainsi qu'un affleurement de niveaux crustaux progressivement plus profonds vers le nord-est a l'intcrieur de l'are.
L'examen de l'affectation des autres unités dans la region de la baie Passamaquoddy aux principals structures teconostratigraphiques au nord de l'ile Campobello clarifie les correlations régionalcs et foumit des liens supplémentaires possibles avec le socle du Protéroique supérieur du secteur.
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