Lake Area Variability Across a Climatic and Vegetational Transect in Southeastern Alberta

Areas of 34 small lakes forming a transect across the southern margin of the Boreal Forest into the Grassland in southern Alberta were obtained from 326 aerial photographs, with at least six photographs for each lake in different months and different years from 1949 to 1992. Standard deviations of standardised lake areas (used as an index of lake area sensitivity to short term climate fluctuations) were plotted against a climatic moisture index; the resulting scatter of points is constrained by a function relating lake sensitivity to long-term regional climatic moisture. The lakes show high sensitivity in the Grassland where potential évapotranspiration exceeds precipitation, a steep drop in sensitivity over a small range of climatic moisture values in the Aspen Parkland, and very low sensitivity in the Boreal Forest where precipitation exceeds potential évapotranspiration.Les superficies de 34 petits lacs constituant un transect à partir de la limite méridionale de la forêt boréale jusqu'à la prairie, dans le sud de l'Alberta. ont été calculées grâce à l'étude de 326 photographies aériennes. Chacun des lacs comptaient au moins six photographies prises à différents mois et échelonnées de 1949 à 1992. Les écarts types de la superficie standardisée des lacs (employés comme indice de la sensibilité de la superficie des lacs aux fluctuations climatiques à court terme) ont été reportés par rapport à l'indice d'humidité. Le nuage de points qui en résulte est commandé par la fonction reliant la sensibilité des lacs à l'humidité du climat régional. Les lacs démontrent une grande sensibilité en prairie où l'évapotranspiration potentielle excède les précipitations, une très forte baisse de sensibilité dans la tremblaie-parc et une très faible sensibilité dans la forêt boréale où les précipitations excèdent l'évapotranspiration potentielle.Die Ausdehnungen von 34 kleinen Seen, welche ein Transect von der sùdlichen Grenze des nôrdlichen Waldgùrtels bis zur Prârie bilden, wurden mittels 326 Luftaufnahmen berechnet; dabei hat man mindestens sechs Aufnahmen fur jeden See gemacht, in verschiedenen Monaten und verschiedenen Jahren von 1949 bis 1992. Die Standardabweichungen von den standardisierten Seen-Oberflàchen (welche als Gradmesser fur die Sensibilitàt der Seen-Oberflâchen auf kurzfristige klimatische Schwankungen benutzt wurden) hat man in Bezug auf den klimatischen Feuchtigkeitsindex ubertragen: die hierdurch erzielte Streuung von Punkten ist durch die Funktion bestimmt, welche die Seen-Sensibilitât mit langzeitiger regionaler klimatischer Feuchtigkeit verbindet. Die Seen weisen eine hohe Sensibilitàt in der Prârie auf, wo die potentielle Evapotranspiration die Niederschlàge ùbertrifft, eine jâhe Abnahme der Sensibilitàt ùber einer kleinen Reihe von klimatischen Feuchtig-keitswerten im Aspen Parkland, und sehr niedrige Sensibilitàt im nôrdlichen WaIdgùrtel, wo die Niederschlàge hoher als die potentielle Evapotranspiration sind

Weathering the storm: developments in the acoustic sensing of wind and rain

An Acoustic Rain Gauge (ARG) analyses the underwater sound levels across a wide frequency range, classifies the observed spectrum according to likely source and then determines the local wind speed or rain rate as appropriate. Thispaper covers a trial on the Scotian Shelf off Canada, comparing the geophysical information derived from the acoustic signals with those obtained from other sources

Adding product value through additive manufacturing

The term additive manufacturing (AM) refers to layer-based material addition technologies that have extended the approach of rapid prototyping (RP) technologies to end-use products and components. The application of AM technologies for this purpose is still rather limited at present but there are a few widely publicised examples. The authors believe that the wider use of AM is being inhibited by the inability of most designers to fully appreciate the contribution that AM can make to E3 (economic, ecological and experience) product value. Research at (removed for anonymity) has indicated that AM can contribute in each of these areas. This paper defines E3 value and then gives some examples of AM products that demonstrate different means of improving value. The conclusions drawn are that AM has an important role to play in adding E3 value to many products but that designers must be better informed as to how to integrate this added value into their designs

Bed-load effects on hydrodynamics of rough-bed open-channel flows

Peer reviewedPublisher PD

Platinum-group element geochemistry of the Forest Reef Volcanics, southeastern Australia: Implications for porphyry Au-Cu mineralisation

Platinum-group element concentrations in felsic to intermediate rocks from the Forest Reef Volcanics, Cadia-Neville region, southeastern Australia have been analysed by the Ni-S fire assay-isotope dilution method. The Forest Reef Volcanics are shoshonitic to calc-alkaline in composition and fractionated to produce a wide range of compositions, with MgO varying between 9.7 and 1.8 wt.%. The interest in this suite is that it is coeval with Au-Cu porphyry-style mineralisation in the Cadia mineral district. This study uses PGE geochemistry to determine the timing of sulfide saturation, relative to volatile (ore-fluid) saturation, in the magma that gave rise to the Forest Reef Volcanics and, in turn, to assess how this timing affected the mineralisation potential of the evolving magmatic system. The Forest Reef Volcanics can be subdivided, on the basis of their contrasting PGE geochemistry, into high-Mg (>6.8 wt.% MgO) and low-Mg suites (≤6.8 wt.% MgO). Platinum, Pd and Re concentrations increase in the high-Mg samples, whereas Ir and Ru decrease and Rh concentrations remain steady, with decreasing MgO. The coupled Ir, Ru and Rh depletion is attributed to the partitioning of these elements into magnetite. The rate of Pt and Pd enrichment is not possible by closed-system fractional crystallisation alone, which suggests that the parent magma was replenished by a Pt-Pd-rich melt. In contrast, the PGE concentrations in the low-Mg samples decrease with decreasing MgO indicating the onset of sulfide saturation at 6.8 wt.% MgO, which is confirmed by the presence of spheroidal sulfide inclusions in liquidus crystals (i.e. clinopyroxene, plagioclase, magnetite). The rate of Pd depletion is appreciably less than for any other sulfide saturated felsic system for which data are available. This requires either that the amount of sulfide melt to have precipitated was unusually low, or that the rate of Pd depletion was limited by the mass of silicate melt the sulfide melt reached equilibrium with, or both. In any event, the fraction of sulfide melt that precipitated was too small to have had a significant effect on the Cu and Au content of the magma so that both Cu and Au were available to enter the ore-forming fluid when the magma became volatile saturated at, or shortly after, it reached ca. 2.9 wt.% MgO.This research was funded by a Newcrest Mining LTD Grant to Ian Campbell

Modeling the near-UV band of GK stars, Paper II: NLTE models

We present a grid of atmospheric models and synthetic spectral energy distributions (SEDs) for late-type dwarfs and giants of solar and 1/3 solar metallicity with many opacity sources computed in self-consistent Non-Local Thermodynamic Equilibrium (NLTE), and compare them to the LTE grid of Short & Hauschildt (2010) (Paper I). We describe, for the first time, how the NLTE treatment affects the thermal equilibrium of the atmospheric structure (T(tau) relation) and the SED as a finely sampled function of Teff, log g, and [A/H] among solar metallicity and mildly metal poor red giants. We compare the computed SEDs to the library of observed spectrophotometry described in Paper I across the entire visible band, and in the blue and red regions of the spectrum separately. We find that for the giants of both metallicities, the NLTE models yield best fit Teff values that are ~30 to 90 K lower than those provided by LTE models, while providing greater consistency between \log g values, and, for Arcturus, Teff values, fitted separately to the blue and red spectral regions. There is marginal evidence that NLTE models give more consistent best fit Teff values between the red and blue bands for earlier spectral classes among the solar metallicity GK giants than they do for the later classes, but no model fits the blue band spectrum well for any class. For the two dwarf spectral classes that we are able to study, the effect of NLTE on derived parameters is less significant.Comment: Submitted to The Astrophysical Journal. Observed spectrophotometric library, and grids of NLTE and LTE) synthetic spectra for GK stars available at http://www.ap.smu.ca/~ishort/PHOENI

Clinical stakeholders' opinions on the use of selective decontamination of the digestive tract in critically ill patients in intensive care units : an international Delphi study

Peer reviewedPublisher PD

Leading at the Coal-face: The World as Experienced by Subject Coordinators in Australian Higher Education

This article is based on nationally funded research into the role, capabilities, challenges and professional development needs of subject coordinators in Australian higher education. The second of three data collection phases involved a multi-institutional survey of staff in the role of subject coordinator with the aim of understanding the role through the experiences of those who undertake it. In particular the conceptualization of this lowest level in academe as one of ‘leadership’, and as being the first rung on the academic leadership ladder, formed the underpinning logic for data collection. Results allow for a contemporary picture of leadership responsibilities to be drawn and also highlights some of the challenges which confront staff in this role. The vast majority of staff consider themselves as demonstrating leadership, although they have varying views about how others higher in the management hierarchy understand and appreciate their role. Most see themselves as performing effectively with the key challenges they face highlighted in the article. Outcomes suggest the need to undertake substantial capacity building of leadership for new and incumbent subject coordinators in response to the ever-changing nature of the higher education environment

Ga and Ce ion-doped phosphate glass fibres with antibacterial properties and their composite for wound healing applications

© 2019 The Royal Society of Chemistry. Novel gallium/cerium-doped phosphate glass fibres (PGF) were successfully manufactured by the melt-quenching and melt-spinning process. The amorphous character of the materials produced was confirmed using X-ray powder diffraction (XRD), and the elemental composition was investigated with X-ray fluorescence confirming the presence of 2 mol% of Ga2O3 or CeO2. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of Q1 and Q2 structural phosphate species. Mechanical properties of the PGFs revealed tensile strength values of 428 ± 94 MPa and 379 ± 80 MPa, with elastic modulus values of 45 ± 4 GPa and 54 ± 9 GPa for Ce-PGF (diameter 25 μm) and Ga-PGF (diameter 18 μm), respectively. The influence of both dopants on the glass degradation properties was evaluated by tests in deionised water, which revealed a decreased dissolution rate for gallium-doped PGF in comparison to cerium-doped PGF. Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) measurements were used to explore ion release in cell culture medium, while ICP-mass spectrometry (ICP-MS) was used to measure ion release in deionised water. These techniques showed controlled release of therapeutic and antibacterial ions from the PGF. Antibacterial properties of Ce-PGF and Ga-PGF, based on turbidity measurements, were confirmed against Gram-positive bacteria. Moreover, Ce-doped phosphate glass fibres did not disturb the proliferation of human epidermal keratinocyte (HaCaT) cells or the mobility of mice embryonic fibroblasts (MEF). Applying an in vitro scratch assay showed full wound closure after 24 h of indirect incubation with Ga-PGF. Due to their superior processability as compared with Ga-PGFs, a fully degradable mesh based on Ce-PGF was designed and found to achieve high water uptake (up to 800%), suggesting its suitability for wound healing applications