A plasma vortex revisited: The importance of including ionospheric conductivity measurements

In an earlier paper [Kosch et al., 1998], simultaneous all-sky TV imager and Scandinavian Twin Auroral Radar Experiment (STARE) observations of an ionospheric plasma vortex located poleward of an auroral arc were presented. The vortex is associated with a sudden brightening of the arc and corresponds to an ionospheric region of diverging horizontal electric fields, which is equivalent to a downward field-aligned current (FAC), i.e., the closure current for the upward current above the arc. This event has been revisited because of the subsequent availability of data from the Scandinavian Magnetometer Array. These data, combined with STARE electric fields, have been used to determine the real ionospheric conductance distribution throughout the field of view. As a result, a more realistic, quantitative picture of the current system associated with the arc is obtained than was possible in an earlier model based on an assumed constant conductance. In particular, a complete macroscopic electrodynamic description of a plasma vortex, composed of ionospheric conductances, true horizontal currents, and FACs, is obtained for the first time. It is shown that the plasma vortex corresponds to an area of decreased conductance, thus broadening the FAC distribution and reducing the current density compared to the earlier results. The study illustrates that horizontal conductance gradients should not be neglected when computing FACs

The distribution of coastal group landhoppers (Crustacea:Amphipoda: Talitridae) related to sea spray at Cox Bight, Tasmania

Terrestrial amphipod crustaceans from two ecological groups, the coastal group and the forest group, were collected along two transects at right angles to the shoreline at Cox Bight, southwestern Tasmania. The transects were placed on either side of Point Eric to ensure that one was more sheltered from seaspray, in order to examine the hypothesis that the distribution of coastal group landhoppers is controlled by the inland penetration of ionic precipitation. Coastal species extended twice as far inland on the exposed transect, and their distribution on both transects correlated strongly with raised levels of sodium in the soil, providing good circumstantial support for the hypothesis. The study highlights the ecological importance of the coastal zone in the World Heritage Area. Further studies should examine the effect of manipulating soil ion levels on the distribution of coastal species

Crowding out the Archivist? Implications of online user participation for archival theory and practice.

This thesis charts a course through an emerging landscape of online user participation in archives, focusing upon user involvement at the point of practice known to professional archivists as archival description. Recent years have seen significant growth in participatory initiatives in the archive sector, and the application of Web 2.0 technologies — augmenting traditions of user engagement and volunteering — has been widely heralded as a new opportunity to ‘democratise’ archival practice. The study considers a spectrum of online initiatives which have sought to benefit from the skills or knowledge of diverse user groups: from mass participation ‘crowdsourcing’ transcription projects, via tagging and commenting functionalities added to traditional archive catalogues, to community engagement programmes which have attempted to build up multiple layers of narrative interpretation. The research was designed around three principal stakeholder groups, professionals, participants, and users, seeking to address three main research questions: • Does online user participation constitute an evolution or a revolution in archival practice and professionalism? • What contexts and circumstances motivate and sustain participation? • Who benefits from user participation in archival description? Two new analytical frameworks are presented as navigation aids for this exploration of participatory archives, taken from the perspective of professional archivists and of participants respectively. The discussion on users is necessarily more speculative, but concludes that realisation of the claims made for the transformative impact of online user participation is dependent upon a redefinition of archival use which is inclusive of both participation and the communication of meaning, in addition to the routine processes of information seeking. Future research directions are identified therefore which lie at the points of intersection between engagement (participation and use combined) and professional theory and practice

Avalanches, climate and glaciers - a reconstruction based on lake sediments from lake Kjøsnesfjorden

To kjerneprøver fra Kjøsnesfjorden, Vestland, har blitt analysert for å undersøke den glasiale historien og massebevegelser i holocen. Tidligere undersøkelser, klimatiske data og et kvartærgeologisk kart ble brukt for å få en dypere forståelse av prosessene i området. En detaljert sedimentologisk analyse, inkludert målinger av magnetisk mottagelighet, glødetap, XRF-kjerneskanning, røntgen CT skanning, og hovedkomponentanalyse (PCA) har blitt gjennomført. En batymetrisk undersøking og CHIRP profiler ble studert for å undersøke geomorfologien i Kjøsnesfjorden. Basert på multi-proksianalyse, litostratigrafien og alder-dybdemodellen har tre avsettende agenser blitt identifisert (snøskred, glasifluviale- og fluviale prosesser) i kjerneprøve 603-21-01PC. Resultatet viser at ni snøskredhendelser, syv under «lille istis» ble oppdaget av et økt antall grove partikler i kjerneprøven. Dette prosjektet sitt andre mål var å undersøke den glasiale historien til Jostedalsbreen og Grovabreen. Etter sediment og XRF-analysen, ble hovedkomponentanalyse (PCA) utført for å skille mellom minerogene og ikke-minerogene enheter i kjerne 603-21-08PC. Resultatet viste at Titan var en god proksi for glasial aktivitet. Undersøkelsen viste en økt glasial aktivitet fra 7800 til 7900 år før nåtid, under «Finse hendelsen». En brå nedgang i aktivitet etter «Finse hendelsen» ble etterfulgt av en gradvis økt aktivitet fra 7000 år før nåtid fram til på 1990-talet, da breene starta å trekke seg tilbake. Det glasiale signalet fra kjerneprøvene undersøkt i dette prosjektet viser lignende utvikling som fra andre studier i området. Forskjellen er at det blir foreslått et tidligere breframrykk ved 7000 år før nåtid, og at det var en liten isbre på Jostedalsbreplatået.Master's Thesis in Earth ScienceGEOV399MAMN-GEO

Electrodynamics of an omega-band as deduced from optical and magnetometer data

We investigate an omega-band event that took place above northern Scandinavia around 02:00–02:30 UT on 9 March 1999. In our analysis we use ground based magnetometer, optical and riometer measurements together with satellite based optical images. The optical and riometer data are used to estimate the ionospheric Hall and Pedersen conductances, while ionospheric equivalent currents are obtained from the magnetometer measurements. These data sets are used as input in a local KRM calculation, which gives the ionospheric potential electric field as output, thus giving us a complete picture of the ionospheric electrodynamic state during the omega-band event. <br><br> The overall structure of the electric field and field-aligned current (FAC) provided by the local KRM method are in good agreement with previous studies. Also the <I><B>E</B></I>&times;<I><B>B</B></I> drift velocity calculated from the local KRM solution is in good qualitative agreement with the plasma velocity measured by the Finnish CUTLASS radar, giving further support for the new local KRM method. The high-resolution conductance estimates allow us to discern the detailed structure of the omega-band current system. The highest Hall and Pedersen conductances, ~50 and ~25 S, respectively, are found at the edges of the bright auroral tongue. Inside the tongue, conductances are somewhat smaller, but still significantly higher than typical background values. The electric field shows a converging pattern around the tongues, and the field strength drops from ~40 mV/m found at optically dark regions to ~10 mV/m inside the areas of enhanced conductivity. Downward FAC flow in the dark regions, while upward currents flow inside the auroral tongue. Additionally, sharp conductance gradients at the edge of an auroral tongue are associated with narrow strips of intense FACs, so that a strip of downward current flows at the eastern (leading) edge and a similar strip of upward current is present at the western (trailing) edge. The Joule heating follows the electric field pattern, so that it is diminished inside the bright auroral tongue

Organisational Culture of Construction Joint Ventures: Case Studies in Hong Kong

CIB W112Includes bibliographical references.Culture can be regarded as a system of shared meanings that organises values into mental programmes which guide the behaviours of people within communities – notably, nations and organisations. Organisational culture involves cognition, affect and behaviour and reflects customary thinking, feeling and acting that are attributed to a particular group of people as they learn to cope with their environment. Largely, behaviours of organisations depend on the decisions and business strategies of top management and are greatly influenced by culture. There is a close relationship between the characteristics of organisational culture in a joint venture (JV) organisation and the parent companies; often, the organisational culture of the (most) powerful parent company dominates. That reflection relates to the top management’s strategy and the allocation of authority among JV partners. The two case studies investigate the organisational culture of international JV projects in Hong Kong that pool resources from parents with different cultural backgrounds. One of the case studies compares the JV organizational culture with the parent companies from UK, Hong Kong and mainland China. The organizational cultures of the parent companies are consistent with their own national cultural characteristics but, in the JV where more than one national culture is involved, the JV organizational culture is highly influenced by the dominant national culture of the management team. In the second case study, the project director is seconded from the dominant parent company. That JV exhibits cultural characteristics which show a synergy of elements from the founding parents but with emphasis on the culture of the dominant partner in the JV

Freshwater invertebrate fauna of the Lake Meston area

Collections of littoral invertebrates were made from 21 freshwater bodies in the Lake Meston area of the western Central Plateau. Seventy-three taxa, including 42 identified as species, were collected. The fauna is similar to that found in other high-altitude lakes in Tasmania. A cluster analysis of sites by the presence or absence of species classified the standing waters into groups which could be explained by size and their species richness, apart from Lake Bill, probably the only lake of non-glacial origin, which did not associate with lakes of similar size. No correlations could be detected between the groupings and topographic descriptors of the lakes derived from maps. The named lakes in order of species richness were Meston (29 species), Adelaide & Louisa (23), Poa (19), Myrtle (IS), Bill (II) and Charles (7). Lake Meston is apparently the only lake in the area to support a substantial trout populatio