1,108 research outputs found

    Shifting sands

    Get PDF
    The article presents the proposed changes to the New Zealand Draft Curriculum on the Nature of Science. In July 2006, the draft was released to school and the wider educational community for consultation on the national curriculum policy. It asserts to help science teachers to develop their understanding on nature of scientific knowledge and on how the community can effectively teach such aspects of the curriculum in the classroom setting

    Effects of deposit-feeding bivalve (Macomona liliana) density on intertidal sediment stability

    Get PDF
    Effects of macrofaunal feeding and bioturbation on intertidal sediment stability (u*crit) were investigated by manipulating density (0-3 x ambient) of the facultative deposit-feeding wedge shell (Macomona liliana) on the Tuapiro sandflat in Tauranga Harbour, New Zealand. Sediment stability increased up to 200% with decreasing M. liliana density and this was correlated with greater sediment microalgal biomass and mucilage content. The change in stability occurred despite homogeneity of grain size amongst experimental treatments, highlighting the importance of macrofaunal-microbial relationships in determining estuarine sediment erodibility

    M-theory and the string genus expansion

    Full text link
    The partition function of the membrane is investigated. In particular, the case relevant to perturbative string theory of a membrane with topology S1×ΣS^1 \times \Sigma is examined. The coupling between the string world sheet Euler character and the dilaton is shown to arise from a careful treatment of the membrane partition function measure. This demonstrates that the M-theory origin of the dilaton coupling to the string world sheet is quantum in nature.Comment: 12 pages, late

    Predicting elections from politicians’ faces

    Get PDF
    Prior research found that people’s assessments of relative competence predicted the outcome of Senate and Congressional races. We hypothesized that snap judgments of "facial competence" would provide useful forecasts of the popular vote in presidential primaries before the candidates become well known to the voters. We obtained facial competence ratings of 11 potential candidates for the Democratic Party nomination and of 13 for the Republican Party nomination for the 2008 U.S. Presidential election. To ensure that raters did not recognize the candidates, we relied heavily on young subjects from Australia and New Zealand. We obtained between 139 and 348 usable ratings per candidate between May and August 2007. The top-rated candidates were Clinton and Obama for the Democrats and McCain, Hunter, and Hagel for the Republicans; Giuliani was 9th and Thompson was 10th. At the time, the leading candidates in the Democratic polls were Clinton at 38% and Obama at 20%, while Giuliani was first among the Republicans at 28% followed by Thompson at 22%. McCain trailed at 15%. Voters had already linked Hillary Clinton’s competent appearance with her name, so her high standing in the polls met our expectations. As voters learned the appearance of the other candidates, poll rankings moved towards facial competence rankings. At the time that Obama clinched the nomination, Clinton was ahead in the popular vote in the primaries and McCain had secured the Republican nomination with a popular vote that was twice that of Romney, the next highest vote-getter.accuracy; appearance; forecasting methods; snap judgments

    Derivation of Economic and Social Indicators for a Spatial Decision Support System to Evaluate the Impacts of Urban Development on Water Bodies in New Zealand

    Get PDF
    There is mounting evidence that urban development in New Zealand has contributed to poor water quality and ecological degradation of coastal and fresh water receiving waters. As a consequence, local governments have identified the need for improved methods to guide decision making to achieve improved outcomes for those receiving waters. This paper reports progress on a research programme to develop a catchmentscale spatial decision-support system (SDSS) that will aid evaluation of the impacts of urban development on attributes such as water and sediment quality; ecosystem health; and economic, social and cultural values. The SDSS aims to express indicators of impacts on these values within a sustainability indexing system in order to allow local governments to consider them holistically over planning timeframes of several decades. The SDSS will use a combination of deterministic and probabilistic methods to, firstly, estimate changes to environmental stressors such as contaminant loads from different land use and stormwater management scenarios and, secondly, use these results and information from a range of other sources to generate indicator values. This paper describes the project’s approach to the derivation of indicators of economic and social well being associated with the effects of urban storm water run-off on freshwater and estuarine receiving waters.Environmental Economics and Policy,

    Complement activation and protein adsorption by carbon nanotubes

    Get PDF
    As a first step to validate the use of carbon nanotubes as novel vaccine or drug delivery devices, their interaction with a part of the human immune system, complement, has been explored. Haemolytic assays were conducted to investigate the activation of the human serum complement system via the classical and alternative pathways. Western blot and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques were used to elucidate the mechanism of activation of complement via the classical pathway, and to analyse the interaction of complement and other plasma proteins with carbon nanotubes. We report for the first time that carbon nanotubes activate human complement via both classical and alternative pathways. We conclude that complement activation by nanotubes is consistent with reported adjuvant effects, and might also in various circumstances promote damaging effects of excessive complement activation, such as inflammation and granuloma formation. C1q binds directly to carbon nanotubes. Protein binding to carbon nanotubes is highly selective, since out of the many different proteins in plasma, very few bind to the carbon nanotubes. Fibrinogen and apolipoproteins (AI, AIV and CIII) were the proteins that bound to carbon nanotubes in greatest quantit

    Response Characteristics of a Short Range, High resolution, Digital Sonar Altimeter

    Get PDF
    The Datasonics Model ASA-920 digital sonar altimeter (DSA) is a compact, high frequency (1 MHz), short range (0.5 to 5 m) underwater sonar device originally designed as an altimeter for submersib1es. Wright et al. (1986) have used the DSA successfully to measure changes in relative bed elevation at a point on the shoreface prior to and during a storm. Fixed to a rigid mounting on the seabed, the DSA produces a digital output that is proportional to the transducer elevation above the bed. The purpose of this report is to describe the response characteristics of the DSA

    A quantum mechanical approach to establishing the magnetic field orientation from a maser Zeeman profile

    Full text link
    Recent comparisons of magnetic field directions derived from maser Zeeman splitting with those derived from continuum source rotation measures have prompted new analysis of the propagation of the Zeeman split components, and the inferred field orientation. In order to do this, we first review differing electric field polarization conventions used in past studies. With these clearly and consistently defined, we then show that for a given Zeeman splitting spectrum, the magnetic field direction is fully determined and predictable on theoretical grounds: when a magnetic field is oriented away from the observer, the left-hand circular polarization is observed at higher frequency and the right-hand polarization at lower frequency. This is consistent with classical Lorentzian derivations. The consequent interpretation of recent measurements then raises the possibility of a reversal between the large-scale field (traced by rotation measures) and the small-scale field (traced by maser Zeeman splitting).Comment: 10 pages, 5 Figures, accepted for publication in MNRA

    Low-energy bedload transport by combined wave and current flow on a southern mid-Atlantic bight shoreface

    Get PDF
    The control of the mean flow, wind-wave energy and wind-wave asymmetry on low-energy bedload transport magnitude, direction and divergence on a wave-dominated shoreface was investigated. The objective was to develop a mechanistic basis for postulated fairweather replenishment of the beach sediment prism by sediments derived from offshore. Fairweather currents were measured at 17.5-m and 22-m depth. Periods of competent flow were identified using a combined-flow boundary-layer model. Madsen and Grant\u27s (1976) combined-flow bedload-transport model was used to calculate sediment fluxes after modification of the expression for instantaneous transport rate to include a threshold criterion; this was necessary since sediment is not in motion over the whole wave period in low-energy conditions. The asymmetry thus introduced into the instantaneous transport rate resulted in partial control over transport direction by the wave. When the flow was competent, oscillatory motion contributed &\u3e&80% of the total skin friction. Net transport direction was controlled by: relative orientation of the wave and mean flow; orbital velocity asymmetry; and the threshold criterion. Threshold-induced rotation of the net transport vector was significant on the lower shoreface where the flow was not intense and the wave-orbital velocity not greatly skewed. Bedload-flux divergence associated with each observed event was simulated using a one-dimensional numerical model. Two scenarios were identified: (1) offshore transport seaward of 10-m depth under the dominant influence of the mean flow, and onshore transport at the top of the shoreface under the dominant influence of shoreward-skewed wave-orbital velocities, and (2) onshore transport at every point on the profile. Direct observations of currents and upper-shoreface accretion in 8-m depth (a total of 6 cm in 4.5 days) were consistent with the model simulations, with the mean flow controlling net transport direction. Observations and model calculations were consistent with the concept of fairweather nourishment of the beach sediment prism by sediment transported from offshore, however the mean flow may play a more important role than previously recognized
    corecore