Influencing students' construction of personalised concept maps through the use of query expansion (QE) searching of the World Wide Web

Despite the on-going development of search engines, users of the World Wide Web, including school and undergraduate students, still find searching for appropriate information problematic. Keener students may seek relevant information to help them to construct a better understanding of the various concepts within a taught subject. Unfortunately there is no guarantee that the information contained in the located documents is of sufficient educational quality; measured for example in terms of the information's usefulness, accuracy, relevancy, trustworthiness, level of language, completeness and status. In this research it is argued that a domain expert (perhaps in the form of a "web literate" subject tutor) has several major advantages over a school or undergraduate student when it comes to searching for relevant subject-related informatio

The process of serpentinization in dunite from New Caledonia

Dunite from New Caledonia displays three types of serpentine-dominated veins. The earliest, type 1 veins are narrow (50–100 μm wide) and rarely extend across more than a single olivine grain. They are lizardite, contain abundant brucite and never contain magnetite. Type 2 veins are 0.01 to 0.1 mm wide, extend across several olivine grains and cut across the type 1 veins. They are lizardite, contain magnetite, often in vein interiors, and contain less brucite than type 1 veins. Type 3 veins are dominantly chrysotile, cm-scale, have a magnetite-rich core, and extend for meters or more. Analyses of two representative samples indicate that the type 1 veins have relatively Fe-rich serpentine (XMg = 0.92) and brucite (XMg = 0.82). These minerals are less magnesian than those in the type 2 veins; serpentine has XMg = 0.93–0.94 and brucite has XMg = 0.84. In the magnetite-rich core to the type 3 vein both serpentine (XMg = 0.94–0.97) and one of the two brucite populations (XMg = 0.94) are Mg-rich. Opx in harzburgite layers in these samples is cut by serpentine veins that are on the order of 0.05 mm wide. The serpentine veins after Opx lack talc or magnetite and, as with veins cutting olivine, the older veins are more Fe rich (XMg = 0.84) than the younger veins (XMg = 0.90). We conclude that the formation of magnetite was accompanied by the extraction of iron from the early-formed serpentine and brucite.Thermodynamic calculations suggest that the type 1 veins formed in a rock-dominated system where the activities of FeO, MgO, and SiO2 were dictated by the compositions of olivine and orthopyroxene. In contrast the type 2 veins were formed in a more fluid-dominated system where the infiltrating fluid was relatively oxidizing and out of equilibrium with the original brucite–serpentine assemblage. Reduction of this fluid was accompanied by reaction of brucite and serpentine to magnetite and hydrogen. By producing magnetite, this reaction extracted iron from brucite and serpentine, making them both more magnesian. This would drive the brucite–serpentine–magnetite assemblage to higher oxygen fugacity, progressively decreasing the efficiency of the magnetite-forming reactions

Influencing students' construction of personalised concept maps through the use of query expansion (QE) searching of the World Wide Web

Despite the on-going development of search engines, users of the World Wide Web, including school and undergraduate students, still find searching for appropriate information problematic. Keener students may seek relevant information to help them to construct a better understanding of the various concepts within a taught subject. Unfortunately there is no guarantee that the information contained in the located documents is of sufficient educational quality; measured for example in terms of the information's usefulness, accuracy, relevancy, trustworthiness, level of language, completeness and status. In this research it is argued that a domain expert (perhaps in the form of a "web literate" subject tutor) has several major advantages over a school or undergraduate student when it comes to searching for relevant subject-related informatio

PucC and LhaA direct efficient assembly of the light-harvesting complexes in <i>Rhodobacter sphaeroides</i>

The mature architecture of the photosynthetic membrane of the purple phototroph Rhodobacter sphaeroides has been characterised to a level where an atomic-level membrane model is available, but the roles of the putative assembly proteins LhaA and PucC in establishing this architecture are unknown. Here we investigate the assembly of light-harvesting LH2 and reaction centre-light-harvesting1-PufX (RC-LH1-PufX) photosystem complexes using spectroscopy, pull-downs, native gel electrophoresis, quantitative mass spectrometry and fluorescence lifetime microscopy to characterise a series of lhaA and pucC mutants. LhaA and PucC are important for specific assembly of LH1 or LH2 complexes, respectively, but they are not essential; the few LH1 subunits found in ΔlhaA mutants assemble to form normal RC-LH1-PufX core complexes showing that, once initiated, LH1 assembly round the RC is cooperative and proceeds to completion. LhaA and PucC form oligomers at sites of initiation of membrane invagination; LhaA associates with RCs, bacteriochlorophyll synthase (BchG), the protein translocase subunit YajC and the YidC membrane protein insertase. These associations within membrane nanodomains likely maximise interactions between pigments newly arriving from BchG and nascent proteins within the SecYEG-SecDF-YajC-YidC assembly machinery, thereby co-ordinating pigment delivery, the co-translational insertion of LH polypeptides and their folding and assembly to form photosynthetic complexes. LhaA and PucC form oligomers at the sites where invagination of the cytoplasmic membranes is initiated, and they play important roles in photosystem assembly in the purple phototrophic bacterium Rhodobacter sphaeroides. Establishing the architecture of the photosynthetic membrane involves interplay between LhaA, reaction centre complexes, bacteriochlorophyll synthase, the protein translocase subunit YajC, and the YidC membrane protein insertase. These associations likely coordinate the delivery of pigments and the membrane insertion, folding and assembly of photosystem polypeptides

Performing the Anglo-Scottish Border: Cultural Landscapes, Heritage and Borderland Identities

Recent times have seen much reflection on the nature of the Anglo-Scottish border region; its past, present and potential future. Political concerns have rightly absorbed much of the attention, but at the same time important light has been shed on the legacy of cultural engagements and forms of interaction that might be said to perform and produce this border over time and render it particularly distinctive. A soft, internal border, the territory considered in this article is one with an ancient feudal past and a heavily conserved, preserved and, in parts, still militarized present. It is predominantly rural and characterized by large swathes of forestry, agriculture, and moorland, all of which raise issues of aesthetic and environmental, as well as social and economic sustainability. The concern in the case studies presented in this article is how, through the relational and processual perspectives of border studies and cultural landscapes, we might comprehend the over layered and sedimented histories, the nature of identities, heritage and experience of place here. I consider too the ways in which recent forms of creative practice are contributing to a wider investigation of this region and re-conceptualizing the cultural significance of the border

Ecosystem services of temporary streams differ between wet and dry phases in regions with contrasting climates and economies

1. Temporary streams are dynamic ecosystems in which mosaics of flowing, ponded and dry habitats support high biodiversity of both aquatic and terrestrial species. Species interact within habitats to perform or facilitate processes that vary in response to changing habitat availability. A natural capital approach recognizes that, through such processes, the ‘natural assets’ of all ecosystems deliver services that benefit people. 2. The ecosystem services of temporary streams remain largely unexplored, in particular those provided during ponded and dry phases. In addition, recent characterizations have focused on dryland systems, and it remains unclear how service provision varies among different climatic regions, or between developed and developing economies. 3. We use evidence from interdisciplinary literature to examine the ecosystem services delivered by temporary streams, including the regulating, provisioning and cultural services provided across the continuum from flowing to dry conditions. We focus on service provision during dry phases and wet–dry transitions, across regions with contrasting climates and economic development. 4. Provision of individual services in temporary streams may be reduced, enhanced or changed by surface water loss. Services enhanced by dry phases include provision of higher‐quality subsurface drinking water and unique opportunities for recreation. Shifts between dry and wet phases enable groundwater recharge that mitigates water scarcity, and grant dry‐phase access to sediments deposited during flowing phases. However, the accessibility and thus perceived value of these and other services varies considerably among regions. In addition, accessing provisioning services requires careful management to promote sustainable resource use and avoid ecological degradation. 5. We highlight the need for environmental managers to recognize temporary streams as aquatic–terrestrial ecosystems, and to take actions promoting their diversity within functional socio‐ecological systems that deliver unique service bundles characterized by variability and differing availability in space and time