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Articles 1261 - 1290 of 1481
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Learning The Rules Of The ‘Student Game’: Transforming The ‘Student Habitus’ Through [Im]Mobility, Mark Holton
Learning The Rules Of The ‘Student Game’: Transforming The ‘Student Habitus’ Through [Im]Mobility, Mark Holton
School of Geography, Earth and Environmental Sciences
In recent years, a growing body of literature has emerged concerning the mobilities of students, specifically relating to the interactions between local and non-local students, which can accentuate unequal access to education; social interactions and learner outcomes. Central to much of this literature is a sense that being mobile in institutional choice is the most appropriate and expected approach to successful university life. Conversely, local students, disadvantaged by their age, history, external commitments and immobility, are thought to be unlikely to share the same ‘student experiences’ as their traditional counterparts, leading to feelings of alienation within the student community. This …
Controls On Modern Tributary-Junction Alluvial Fan Occurrence And Morphology: High Atlas Mountains, Morocco, Martin Stokes, Anne E. Mather
Controls On Modern Tributary-Junction Alluvial Fan Occurrence And Morphology: High Atlas Mountains, Morocco, Martin Stokes, Anne E. Mather
School of Geography, Earth and Environmental Sciences
Modern tributary-junction alluvial fans (cone-shaped depositional landforms formed in confined valley settings) were analysed from a 20-km-long reach of the Dades River in the distal part of the fold-thrust belt region in the south-central High Atlas Mountains of Morocco. Here, a deeply dissected network of ephemeral tributary streams and a perennial trunk drainage characterised by an arid mountain desert climate are configured onto a folded and thrust faulted Mesozoic sedimentary sequence. Out of 186 tributary streams, only 29 (16%) generated alluvial fans at their tributary junctions. The fan-generating catchments possess higher relief, longer lengths, lower gradients, and larger areas than …
Exceptional River Gorge Formation From Unexceptional Floods, L. Anton, A. E. Mather, M. Stokes, A. Muñoz-Martin, Vicente G De
Exceptional River Gorge Formation From Unexceptional Floods, L. Anton, A. E. Mather, M. Stokes, A. Muñoz-Martin, Vicente G De
School of Geography, Earth and Environmental Sciences
An understanding of rates and mechanisms of incision and knickpoint retreat in bedrock rivers is fundamental to perceptions of landscape response to external drivers, yet only sparse field data are available. Here we present eye witness accounts and quantitative surveys of rapid, amphitheatre-headed gorge formation in unweathered granite from the overtopping of a rock-cut dam spillway by small-moderate floods (~100–1,500 m3 s−1). The amount of erosion demonstrates no relationship with flood magnitude or bedload availability. Instead, structural pattern of the bedrock through faults and joints appears to be the primary control on landscape change. These discontinuities facilitate rapid erosion ( …
Historical Comparisons Reveal Multiple Drivers Of Decadal Change Of An Ecosystem Engineer At The Range Edge, Lb Firth, N Mieszkowska, Lm Grant, Le Bush, Et Al
Historical Comparisons Reveal Multiple Drivers Of Decadal Change Of An Ecosystem Engineer At The Range Edge, Lb Firth, N Mieszkowska, Lm Grant, Le Bush, Et Al
School of Geography, Earth and Environmental Sciences
Biogenic reefs are important for habitat provision and coastal protection. Long-term datasets on the distribution and abundance of Sabellaria alveolata (L.) are available from Britain. The aim of this study was to combine historical records and contemporary data to (1) describe spatiotemporal variation in winter temperatures, (2) document short-term and long-term changes in the distribution and abundance of S. alveolata and discuss these changes in relation to extreme weather events and recent warming, and (3) assess the potential for artificial coastal defense structures to function as habitat for S. alveolata. A semi-quantitative abundance scale (ACFOR) was used to compare broadscale, …
Book Review: Encountering Affect: Capacities, Apparatuses, Conditions, Paul Simpson
Book Review: Encountering Affect: Capacities, Apparatuses, Conditions, Paul Simpson
School of Geography, Earth and Environmental Sciences
No abstract provided.
Sustainable Deathstyles? The Geography Of Green Burials In Britain, Richard Yarwood, James D. Sidaway, Claire Kelly, Susie Stillwell
Sustainable Deathstyles? The Geography Of Green Burials In Britain, Richard Yarwood, James D. Sidaway, Claire Kelly, Susie Stillwell
School of Geography, Earth and Environmental Sciences
In the context of a wider literature on ‘deathscapes’, we map the emergence of a new mode of burial and remembrance in Britain. Since a ‘green’ burial ground was established in Carlisle in 1993, sites for so-called ‘green, ‘natural’ or ‘woodland’ funerals have proliferated. There are now over 270 such sites in Britain. Drawing on a postal and email survey sent to all managers/owners and visits to 15 green burial grounds (enabling observations and semi-structured interviews with their managers), we chart their growth, establishment and regulation and describe the landscapes associated with them. This requires, and leads to, wider reflections …
Dynamics Of Intraoceanic Subduction Initiation: 1. Oceanic Detachment Fault Inversion And The Formation Of Supra-Subduction Zone Ophiolites, Marco Maffione, Cedric Thieulot, Douwe J.J. Van Hinsbergen, Antony Morris, Oliver Plümper, Wim Spakman
Dynamics Of Intraoceanic Subduction Initiation: 1. Oceanic Detachment Fault Inversion And The Formation Of Supra-Subduction Zone Ophiolites, Marco Maffione, Cedric Thieulot, Douwe J.J. Van Hinsbergen, Antony Morris, Oliver Plümper, Wim Spakman
School of Geography, Earth and Environmental Sciences
Subduction initiation is a critical link in the plate tectonic cycle. Intraoceanic subduction zones can form along transform faults and fracture zones, but how subduction nucleates parallel to mid-ocean ridges, as in e.g., the Neotethys Ocean during the Jurassic, remains a matter of debate. In recent years, extensional detachment faults have been widely documented adjacent to slow-spreading and ultraslowspreading ridges where they cut across the oceanic lithosphere. These structures are extremely weak due to widespread occurrence of serpentine and talc resulting from hydrothermal alteration, and can therefore effectively localize deformation. Here, we show geochemical, tectonic, and paleomagnetic evidence from the …
Dye Tracing To Determine Flow Properties Of Hydrocarbon-Polluted Rabots Glaciär, Kebnekaise, Sweden, Cc Clason, C Coch, J Jarsjö, Et Al
Dye Tracing To Determine Flow Properties Of Hydrocarbon-Polluted Rabots Glaciär, Kebnekaise, Sweden, Cc Clason, C Coch, J Jarsjö, Et Al
School of Geography, Earth and Environmental Sciences
Over 11 000 L of kerosene was deposited on the surface of Rabots glaciär on the Kebnekaise Massif, northern Sweden, following the crash of a Royal Norwegian Air Force aircraft in March 2012. An environmental monitoring programme was subsequently commissioned, including a series of dye tracing experiments during the 2013 melt season, conducted to investigate the transport of pollutants through the glacier hydrological system. This experimental set-up provided a basis from which we could gain new insight into the internal hydrological system of Rabots glaciär. Results of dye tracing experiments reveal a degree of homogeneity in the topology of the …
Did The Kyrenia Range Of Northern Cyprus Rotate With The Troodos-Hatay Microplate During The Tectonic Evolution Of The Eastern Mediterranean?, Antony Morris, Alastair H.F. Robertson, Mark W. Anderson, Emma Hodgson
Did The Kyrenia Range Of Northern Cyprus Rotate With The Troodos-Hatay Microplate During The Tectonic Evolution Of The Eastern Mediterranean?, Antony Morris, Alastair H.F. Robertson, Mark W. Anderson, Emma Hodgson
School of Geography, Earth and Environmental Sciences
No abstract provided.
Beyond A Bottle Of Liquid: Pesticide Dependence In Transitional Rural China, Z Hu, S Rahman
Beyond A Bottle Of Liquid: Pesticide Dependence In Transitional Rural China, Z Hu, S Rahman
School of Geography, Earth and Environmental Sciences
Pesticide dependence is a major threat to food safety and local environment. Although numerous studies have explored different causes of pesticide dependence, few have examined how pesticides are locked into agricultural modernisation and rural transformation. Based on a case study of a Chinese village, this paper demonstrates how agricultural modernisation trajectory and rural changes have perpetuated the use of pesticides as necessities in agriculture as well as for farmers' livelihoods. Modern technologies, such as hybrid rice, conservation tillage, changes in crop structure, and reduction of intercropping all contribute highly towards pesticide dependence. The household responsibility system in China has provided …
Single-Grain And Multi-Grain Osl Dating Of River Terrace Sediments In The Tabernas Basin, Se Spain, M. R. Geach, K. J. Thomsen, J. P. Buylaert, A. S. Murray, A. E. Mather, M. W. Telfer, M. Stokes
Single-Grain And Multi-Grain Osl Dating Of River Terrace Sediments In The Tabernas Basin, Se Spain, M. R. Geach, K. J. Thomsen, J. P. Buylaert, A. S. Murray, A. E. Mather, M. W. Telfer, M. Stokes
School of Geography, Earth and Environmental Sciences
River terraces represent important records of landscape response to e.g. base-level change and tectonic movement. Both these driving forces are important in the southern Iberian Peninsula. In this study, Optically Stimulated Luminescence (OSL) dating was used to date two principal river terraces in the Tabernas Basin, SE Spain. A total of 23 samples was collected from the fluvial terraces for dating using quartz OSL. Sixteen of the samples could not be dated because of low saturation levels (e.g. typical 2xD0 < 50 Gy). The remaining seven samples (5 fossil and 2 modern analogues) were investigated using both multi-grain and single-grain analysis. Single grain results show that: (i) measurements from multi-grain aliquots overestimate ages by up to ∼ 4 ka for modern analogues and young samples (<5 ka), presumably because (ii) the presence of many saturated grains has biased the multi-grain results to older ages. Despite the unfavourable luminescence characteristics we are able to present the first numerical ages for two terrace aggradation stages in the Tabernas Basin, one at ∼16 ka and the other within the last 2 ka.
Technical And Scale Efficiency Of Cassava Production System In Delta State, Nigeria: An Application Of Two-Stage Dea Approach, S Rahman, Bo Awerije
Technical And Scale Efficiency Of Cassava Production System In Delta State, Nigeria: An Application Of Two-Stage Dea Approach, S Rahman, Bo Awerije
School of Geography, Earth and Environmental Sciences
The present study examines the level of pure technical and scale efficiencies of cassava production system including its sub-processes (that is production and processing stages) of 278 cassava farmers/processors from three regions of Delta State, Nigeria by applying Two-Stage Data Envelopment Analysis (DEA) approach. Results reveal that pure technical efficiency (PTE) is significantly lower at the production stage 0.41 vs 0.55 for the processing stage, but scale efficiency (SE) is high at both stages (0.84 and 0.87), implying that productivity can be improved substantially by reallocation of resources and adjusting operation size. The socio-economic determinants exert differential impacts on PTE …
Modelling Impacts Of Seasonal Wastewater Treatment Plant Effluent Permits And Biosolid Substitution For Phosphorus Management In Catchments And River Systems, P. G. Whitehead, M. N. Futter, S. Comber, D. Butterfield, L. Pope, R. Willows, C. Burgess
Modelling Impacts Of Seasonal Wastewater Treatment Plant Effluent Permits And Biosolid Substitution For Phosphorus Management In Catchments And River Systems, P. G. Whitehead, M. N. Futter, S. Comber, D. Butterfield, L. Pope, R. Willows, C. Burgess
School of Geography, Earth and Environmental Sciences
The issues of diffuse and point source phosphorus (P) pollution in river systems are presented using a catchment model to assess nutrient behaviour, seasonal effluent standards and biosolid substitution. A process-based, dynamic water quality model (INCA-P) has been applied to four UK catchments, namely, the Rivers Tywi, Wensum, Lunan and Hampshire Avon, to simulate water fluxes, sediments, total phosphorus and soluble reactive phosphorus (SRP) concentrations. The model has been used to assess impacts of both agricultural runoff and point P sources from wastewater treatment plants (WWTPs) on water quality. With increasing costs for P fertilizer and P reduction at WWTPs, …
Detergent Less Ultrasound-Assisted Extraction Of Trace Elements From Edible Oils Using Lipase As An Extractant, Derya Kara, Andrew Fisher, Steve Hill
Detergent Less Ultrasound-Assisted Extraction Of Trace Elements From Edible Oils Using Lipase As An Extractant, Derya Kara, Andrew Fisher, Steve Hill
School of Geography, Earth and Environmental Sciences
A new method for the extraction and preconcentration of trace elements (Al, Ba, Cd, Cu, Fe, Mn, Mo, Ni, Ti, V and Zn) from edible oils by producing detergentless micro-emulsions via an ultrasound-assisted extraction using a water phase containing Lipase at pH 3 as an extractant was developed. The trace elements in the water phase post-extraction were determined against matrix matched standards using ICP-MS. In the first step of the work, the parameters that affect extraction, such as pH, the volume of 1% lipase in the water phase and the ultrasonic and centrifugation times were optimized. Under the optimal conditions, …
Swirl Flow Bioreactor Coupled With Cu-Alginate Beads: A System For The Eradication Of Coliform And Escherichia Coli From Biological Effluents, S Atkinson, Sf Thomas, P Goddard, Rm Bransgrove, Et Al
Swirl Flow Bioreactor Coupled With Cu-Alginate Beads: A System For The Eradication Of Coliform And Escherichia Coli From Biological Effluents, S Atkinson, Sf Thomas, P Goddard, Rm Bransgrove, Et Al
School of Geography, Earth and Environmental Sciences
It is estimated that approximately 1.1 billion people globally drink unsafe water. We previously reported both a novel copper-alginate bead, which quickly reduces pathogen loading in waste streams and the incorporation of these beads into a novel swirl flow bioreactor (SFB), of low capital and running costs and of simple construction from commercially available plumbing pipes and fittings. The purpose of the present study was to trial this system for pathogen reduction in waste streams from an operating Dewats system in Hinjewadi, Pune, India and in both simulated and real waste streams in Seattle, Washington, USA. The trials in India, …
Knowledge, Agency And Collective Action As Barriers To Energy-Saving Behaviour, Debby Cotton, Wendy Miller, Jennie Winter, Ian Bailey, Stephen Sterling
Knowledge, Agency And Collective Action As Barriers To Energy-Saving Behaviour, Debby Cotton, Wendy Miller, Jennie Winter, Ian Bailey, Stephen Sterling
School of Geography, Earth and Environmental Sciences
Energy saving is becoming a rising priority as a response to climate change and fossil fuel depletion in recent years. However, despite energy-related behaviour change being an important part of many environmental education initiatives, “energy literacy” among citizens remains patchy in both the USA and the UK, with evidence of strong positive attitudes but less consistent knowledge. Whilst it is clear that increasing knowledge does not automatically produce behaviour changes, potential questions must be asked about the logic of focusing solely on behaviour without simultaneously exploring and enhancing understanding of energy issues. This research, undertaken at a higher education institution …
Holocene Coastal Notches In The Mediterranean Region: Indicators Of Palaeoseismic Clustering?, S. J. Boulton, I. S. Stewart
Holocene Coastal Notches In The Mediterranean Region: Indicators Of Palaeoseismic Clustering?, S. J. Boulton, I. S. Stewart
School of Geography, Earth and Environmental Sciences
No abstract provided.
A Paleoclimatic And Paleoatmospheric Record From Peatlands Accumulating During The Cretaceous-Paleogene Boundary Event, Western Interior Basin, Canada, Rhodri M. Jerrett, Gregory D. Price, Stephen T. Grimes, Alex T. Dawson
A Paleoclimatic And Paleoatmospheric Record From Peatlands Accumulating During The Cretaceous-Paleogene Boundary Event, Western Interior Basin, Canada, Rhodri M. Jerrett, Gregory D. Price, Stephen T. Grimes, Alex T. Dawson
School of Geography, Earth and Environmental Sciences
No abstract provided.
Can Polychlorinated Biphenyl (Pcb) Signatures And Enantiomer Fractions Be Used For Source Identification And To Age Date Occupational Exposure?, David Megson, Jean Françios Focant, Donald G. Patterson, Matthew Robson, Maeve C. Lohan, Paul J. Worsfold, Sean Comber, Robert Kalin, Eric Reiner, Gwen O'Sullivan
Can Polychlorinated Biphenyl (Pcb) Signatures And Enantiomer Fractions Be Used For Source Identification And To Age Date Occupational Exposure?, David Megson, Jean Françios Focant, Donald G. Patterson, Matthew Robson, Maeve C. Lohan, Paul J. Worsfold, Sean Comber, Robert Kalin, Eric Reiner, Gwen O'Sullivan
School of Geography, Earth and Environmental Sciences
Detailed polychlorinated biphenyl (PCB) signatures and chiral Enantiomer Fractions (EFs) of CB-95, CB-136 and CB-149 were measured for 30 workers at a transformer dismantling plant. This was undertaken to identify sources of exposure and investigate changes to the PCB signature and EFs over different exposure periods. Approximately 1.5 g of serum was extracted and PCB signatures were created through analysis by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) and EFs calculated following analysis by gas chromatography with high resolution mass spectrometry (GC-HRMS). A total of 84 PCBs were identified in the serum samples with concentrations of the 7 …
Jography: Exploring Meanings, Experiences And Spatialities Of Recreational Road-Running, Simon Cook, Jon Shaw, Paul Simpson
Jography: Exploring Meanings, Experiences And Spatialities Of Recreational Road-Running, Simon Cook, Jon Shaw, Paul Simpson
School of Geography, Earth and Environmental Sciences
No abstract provided.
Determinants Of Modern Technology Adoption In Multiple Food Crops In Nigeria: A Multivariate Probit Approach, S Rahman, Cd Chima
Determinants Of Modern Technology Adoption In Multiple Food Crops In Nigeria: A Multivariate Probit Approach, S Rahman, Cd Chima
School of Geography, Earth and Environmental Sciences
Farmers generally produce multiple crops while selectively adopting modern technologies in them to meet various needs. The present study jointly determines the factors influencing decisions to adopt modern technologies (i.e., HYV seeds and/or fertilizers) in multiple food crops (i.e., rice, yam and cassava) using a survey data of 400 farmers from Nigeria by applying a multivariate probit model. Model diagnostic reveals that the decisions to adopt modern technologies are significantly correlated, implying that univariate analysis of such decisions are biased, thereby, justifying use of multivariate approach. Results reveal that 68% of the farmers grew at least two food crops. Output …
Eocene And Miocene Extension, Meteoric Fluid Infiltration, And Core Complex Formation In The Great Basin (Raft River Mountains, Utah), K Methner, A Mulch, C Teyssier, Ml Wells, Et Al
Eocene And Miocene Extension, Meteoric Fluid Infiltration, And Core Complex Formation In The Great Basin (Raft River Mountains, Utah), K Methner, A Mulch, C Teyssier, Ml Wells, Et Al
School of Geography, Earth and Environmental Sciences
Metamorphic core complexes (MCCs) in the North American Cordillera reflect the effects of lithospheric extension and contribute to crustal adjustments both during and after a protracted subduction history along the Pacific plate margin. While the Miocene-to-recent history of most MCCs in the Great Basin, including the Raft River-Albion-Grouse Creek MCC, is well documented, early Cenozoic tectonic fabrics are commonly severely overprinted. We present stable isotope, geochronological (40Ar/39Ar), and microstructural data from the Raft River detachment shear zone. Hydrogen isotope ratios of syntectonic white mica (δ2Hms) from mylonitic quartzite within the shear zone are very low (-90‰ to -154‰, Vienna SMOW) …
Sticky Stuff: Redefining Bedform Prediction In Modern And Ancient Environments, Robert J. Schindler, Daniel R. Parsons, Leiping Ye, Julie A. Hope, Jaco H. Baas, Jeff Peakall, Andrew J. Manning, Rebecca J. Aspden, Jonathan Malarkey, Steve Simmons, David M. Paterson, Ian D. Lichtman, Alan G. Davies, Peter D. Thorne, Sarah J. Bass
Sticky Stuff: Redefining Bedform Prediction In Modern And Ancient Environments, Robert J. Schindler, Daniel R. Parsons, Leiping Ye, Julie A. Hope, Jaco H. Baas, Jeff Peakall, Andrew J. Manning, Rebecca J. Aspden, Jonathan Malarkey, Steve Simmons, David M. Paterson, Ian D. Lichtman, Alan G. Davies, Peter D. Thorne, Sarah J. Bass
School of Geography, Earth and Environmental Sciences
The dimensions and dynamics of subaqueous bedforms are well known for cohesionless sediments. However, the effect of physical cohesion imparted by cohesive clay within mixed sand-mud substrates has not been examined, despite its recognized influence on sediment stability. Here we present a series of controlled laboratory experiments to establish the influence of substrate clay content on subaqueous bedform dynamics within mixtures of sand and clay exposed to unidirectional flow. The results show that bedform dimensions and steepness decrease linearly with clay content, and comparison with existing predictors of bedform dimensions, established within cohesionless sediments, reveals significant over-prediction of bedform size …
Selectivity Control In Pt-Catalyzed Cinnamaldehyde Hydrogenation, Lee J. Durndell, Christopher M.A. Parlett, Nicole S. Hondow, Mark A. Isaacs, Karen Wilson, Adam F. Lee
Selectivity Control In Pt-Catalyzed Cinnamaldehyde Hydrogenation, Lee J. Durndell, Christopher M.A. Parlett, Nicole S. Hondow, Mark A. Isaacs, Karen Wilson, Adam F. Lee
School of Geography, Earth and Environmental Sciences
AbstractChemoselectivity is a cornerstone of catalysis, permitting the targeted modification of specific functional groups within complex starting materials. Here we elucidate key structural and electronic factors controlling the liquid phase hydrogenation of cinnamaldehyde and related benzylic aldehydes over Pt nanoparticles. Mechanistic insight from kinetic mapping reveals cinnamaldehyde hydrogenation is structure-insensitive over metallic platinum, proceeding with a common Turnover Frequency independent of precursor, particle size or support architecture. In contrast, selectivity to the desired cinnamyl alcohol product is highly structure sensitive, with large nanoparticles and high hydrogen pressures favoring C = O over C = C hydrogenation, attributed to molecular surface …
Source Apportionment Of Trace Contaminants In Urban Sewer Catchments, Sean Comber, Mike Gardner, Vera Jones, Brian Ellor
Source Apportionment Of Trace Contaminants In Urban Sewer Catchments, Sean Comber, Mike Gardner, Vera Jones, Brian Ellor
School of Geography, Earth and Environmental Sciences
No abstract provided.
Creep Cavitation Bands Control Porosity And Fluid Flow In Lower Crustal Shear Zones, L Menegon, F Fusseis, H Stunitz, X Xiao
Creep Cavitation Bands Control Porosity And Fluid Flow In Lower Crustal Shear Zones, L Menegon, F Fusseis, H Stunitz, X Xiao
School of Geography, Earth and Environmental Sciences
Shear zones channelize fluid flow in Earth’s crust. However, little is known about deep crustal fluid migration and how fluids are channelized and distributed in a deforming lower crustal shear zone. This study investigates the deformation mechanisms, fluid-rock interaction, and development of porosity in a monzonite ultramylonite from Lofoten, northern Norway. The rock was deformed and transformed into an ultramylonite under lower crustal conditions (temperature = 700–730 °C, pressure = 0.65–0.8 GPa). The ultramylonite consists of feldspathic layers and domains of amphibole + quartz + calcite, which result from hydration reactions of magmatic clinopyroxene. The average grain size in both …
Determinants Of Crop Diversity In The Regions Of Bangladesh (1990–2008), S Rahman, Mmh Kazal
Determinants Of Crop Diversity In The Regions Of Bangladesh (1990–2008), S Rahman, Mmh Kazal
School of Geography, Earth and Environmental Sciences
The paper measures the level of crop diversity and identifies factors influencing diversification using a panel data of 17 regions of Bangladesh covering a 19 year period (1990–2008). Results revealed the trends that agricultural areas allocated to high-yielding variety rice, spices and vegetables has increased, while areas cultivating traditional rice, minor cereals, oilseeds, pulses, jute and sugarcane has declined at variable rates across regions with significant differences. The level of crop diversity is also significantly different across regions and has decreased in 2008 from its 1990 level in most regions except Faridpur, Khulna and Sylhet. Among the determinants, an increase …
The Role Of Gravitational Instabilities In Deposition Of Volcanic Ash, I Manzella, C Bonadonna, Jc Phillips, H Monnard
The Role Of Gravitational Instabilities In Deposition Of Volcanic Ash, I Manzella, C Bonadonna, Jc Phillips, H Monnard
School of Geography, Earth and Environmental Sciences
Volcanic ash is a significant hazard for areas close to volcanoes and for aviation. Gravitational instabilities forming at the bottom of spreading volcanic clouds have been observed in many explosive eruptions. Here we present the first quantitative description of the dynamics of such instabilities, and correlate this with the characteristics of the fall deposit from observations of the 4 May 2010 Eyjafjallajökull (Iceland) eruption. Gravitational instabilities initially took the form of downward-propagating fingers that formed continuously at the base of the cloud, and appeared to be advected passively at the crosswind speed. Measurements of finger propagation are consistent with initial …
The Pervasive Role Of Biological Cohesion In Bedform Development., Jonathan Malarkey, Jaco H. Baas, Julie A. Hope, Rebecca J. Aspden, Daniel R. Parsons, Jeff Peakall, David M. Paterson, Robert J. Schindler, Leiping Ye, Ian D. Lichtman, Sarah J. Bass, Alan G. Davies, Andrew J. Manning, Peter D. Thorne
The Pervasive Role Of Biological Cohesion In Bedform Development., Jonathan Malarkey, Jaco H. Baas, Julie A. Hope, Rebecca J. Aspden, Daniel R. Parsons, Jeff Peakall, David M. Paterson, Robert J. Schindler, Leiping Ye, Ian D. Lichtman, Sarah J. Bass, Alan G. Davies, Andrew J. Manning, Peter D. Thorne
School of Geography, Earth and Environmental Sciences
Sediment fluxes in aquatic environments are crucially dependent on bedform dynamics. However, sediment-flux predictions rely almost completely on clean-sand studies, despite most environments being composed of mixtures of non-cohesive sands, physically cohesive muds and biologically cohesive extracellular polymeric substances (EPS) generated by microorganisms. EPS associated with surficial biofilms are known to stabilize sediment and increase erosion thresholds. Here we present experimental data showing that the pervasive distribution of low levels of EPS throughout the sediment, rather than the high surficial levels of EPS in biofilms, is the key control on bedform dynamics. The development time for bedforms increases by up …
Bicyclic Naphthenic Acids In Oil Sands Process Water: Identification By Comprehensive Multidimensional Gas Chromatography-Mass Spectrometry., Michael J. Wilde, Charles E. West, Alan G. Scarlett, David Jones, Richard A. Frank, L. Mark Hewitt, Steven J. Rowland
Bicyclic Naphthenic Acids In Oil Sands Process Water: Identification By Comprehensive Multidimensional Gas Chromatography-Mass Spectrometry., Michael J. Wilde, Charles E. West, Alan G. Scarlett, David Jones, Richard A. Frank, L. Mark Hewitt, Steven J. Rowland
School of Geography, Earth and Environmental Sciences
Although bicyclic acids have been reported to be the major naphthenic acids in oil sands process-affected water (OSPW) and a well-accepted screening assay indicated that some bicyclics were the most acutely toxic acids tested, none have yet been identified. Here we show by comprehensive multidimensional gas chromatography-mass spectrometry (GC×GC-MS), that >100 C8-15 bicyclic acids are typically present in OSPW. Synthesis or purchase allowed us to establish the GC×GC retention times of methyl esters of numerous of these and the mass spectra and published spectra of some additional types, allowed us to identify bicyclo[2.2.1]heptane, bicyclo[3.2.1]octane, bicyclo[4.3.0]nonane, bicyclo[3.3.1]nonane and bicyclo[4.4.0]decane acids in …