2,108 research outputs found
The influence of coastal upwelling on the biodiversity of sandy beaches in South Africa
No full textSandy beaches are often highly allochthonous, depending on external subsidies of carbon and nutrients. Despite this, sandy beach macrofaunal assemblages have received little attention regarding their response to enhanced primary productivity generated from coastal upwelling. This thesis investigates the influence of upwelling on macrofaunal assemblages over a variety of spatial and temporal scales. Spatially, four regions were examined across two biogeographic provinces to remove temperature as a confounding factor, and limit biogeography-specific effects. A nested hierarchical design enabled both large and small scales to be examined and generalities about upwelling effects across multiple areas to be considered. Sampling was conducted in two seasons, and over two years, to test the persistence of any effects. Biogeography and region had the strongest influences on macrofaunal biodiversity. Upwelling influenced macrofaunal assemblages in every region when analyses were conducted at the species level. However, the particular effect, positive or negative, differed among regions depending on local factors, and between the response variables, abundance and biomass. Coarser scales of taxonomy, feeding guild and developmental mode were investigated; however, the influence of upwelling generally became weaker and more varied, and occasionally disappeared. Seasonality was greater on the South Coast but was still important in some analyses on the West Coast. At the small-scale, variation within-beaches was lower than between beaches, assemblage structure remained stable over time, and consistent zonation was not present. The influence of temperature on filtration rate and oxygen consumption of Donax serra was investigated to test a driving mechanism for assemblage responses to upwelling. Feeding ability was significantly reduced at colder temperatures indicating an important factor which may be involved in determining assemblage structure. These results suggest that alterations to upwelling regimes predicted under climate change scenarios will impact sandy beach macrofauna, however the specific outcome will depend on multiple contextual factors
Non-discursive knowledge and the construction of identity. Potters, potting and performance at the bronze age tell of Százhalombatta, Hungary
Full text linkThis article explores the relationship between the making of things and the making of people at the Bronze Age tell at Százhalombatta, Hungary. Focusing on potters and potting, we explore how the performance of non-discursive knowledge was critical to the construction of social categories. Potters literally came into being as potters through repeated bodily enactment of potting skills. Potters also gained their identity in the social sphere through the connection between their potting performance and their audience. We trace degrees of skill in the ceramic record to reveal the material articulation of non-discursive knowledge and consider the ramifications of the differential acquisition of non-discursive knowledge for the expression of different kinds of potter's identities. The creation of potters as a social category was essential to the ongoing creation of specific forms of material culture. We examine the implications of altered potters' performances and the role of non-discursive knowledge in the construction of social models of the Bronze Ag
Structural analysis and parametric study ballasted track in sandy regions
No full textThe sand intrusion in railway tracks in sandy regions can significantly change the mechanical behaviour of tracks and thus threaten the safety of train operation. This paper presents substantial field tests on both sandy and clean railway tracks to study the effect of sand intrusion on the longitudinal resistance of ballast bed and the vibration behaviour of track structures. After that, a 3D multi-scale the discrete element model is developed to study the micro-contact between ballast particles and the vibration behaviour of sandy tracks during train passing in detail. Also, the effect of train speeds and axle loads on the mechanical behaviour of sandy tracks is discussed. The results show that the sand intrusion increases the vibration acceleration amplitude of rail and sleeper by 11.3% and 50.3%, while ballast bed decreases by 44.9%. Besides, the sand intrusion significantly changes the energy distribution in the track, wherein the frequencies of the highest energy of rail and sleeper are increased while that of the ballast bed is decreased. The parametric study shows the high train speed can cause the increase in overall acceleration of the ballast bed and high axle load can cause an increase in the micro-contact forces between ballast particles, diffusion angle of the contact force chain, displacements of ballast particles, acceleration of ballast particles, and sleeper displacements.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Mechanics and Physics of Structure
Crushed rock and clay amelioration of a nutrient decifient, sandy soil of Maputaland
No full textBibliography: leaves 57-62.Various studies have suggested the possibility that food derived through subsistence agriculture in the Mseleni region of Maputaland contributes to malnutrition within the local community, particularfy within the high proportion of the population which suffers from a severe, disabling form of osteoarthritis. This study was conducted to determine if the application of local crushed rock or black clay to these nutrient deficient, sandy soils would increase available nutrient concentrations and improve the growth of plants in the ameliorated soil
Sandy coastlines under threat of erosion
Full text linkSandy beaches occupy more than one-third of the global coastline1 and have high socioeconomic value related to recreation, tourism and ecosystem services2. Beaches are the interface between land and ocean, providing coastal protection from marine storms and cyclones3. However the presence of sandy beaches cannot be taken for granted, as they are under constant change, driven by meteorological4,5, geological6 and anthropogenic factors1,7. A substantial proportion of the world’s sandy coastline is already eroding1,7, a situation that could be exacerbated by climate change8,9. Here, we show that ambient trends in shoreline dynamics, combined with coastal recession driven by sea level rise, could result in the near extinction of almost half of the world’s sandy beaches by the end of the century. Moderate GHG emission mitigation could prevent 40% of shoreline retreat. Projected shoreline dynamics are dominated by sea level rise for the majority of sandy beaches, but in certain regions the erosive trend is counteracted by accretive ambient shoreline changes; for example, in the Amazon, East and Southeast Asia and the north tropical Pacific. A substantial proportion of the threatened sandy shorelines are in densely populated areas, underlining the need for the design and implementation of effective adaptive measures.Accepted Author ManuscriptCoastal Engineerin
Column on author Sandy Phippen, who was born in White Plains, NY, but moved to M
No full textColumn on author Sandy Phippen, who was born in White Plains, NY, but moved to Maine when he was two months old, and a review of his new book, Kitchen Boy
Lloyd (Sandy) H. Ellis Jr. Interview, 2011
No full textThis is an interview with author Lloyd (Sandy) H. Ellis Jr. about his book Sacred Landmarks and his forthcoming book which extends the first work beyond the city limits. In the first part of the interview there is discussion about the first book and how his new book will extend beyond the city limits to look at other sacred landmarks around the city. The next part of the interview Ellis notes the problems with getting access to some institutions and differences between religious groups and the clergy. Throughout the interview unique aspects of these landmarks are noted as well as religious differences. The later part of the interview Ellis notes how the churches have evolved and how parishioners have given insight to these landmarks. At the end of the interview discussion concludes with how the builders deserve credit along with the designers in construction of these landmarks. Ellis also points out how many founding pastors provided the initiative, fund raising, and drive for the construction of these institutions
The Political Economy of the Corporation: Sahil Jai Duta Interviews Sandy Brian Hager
Full text linkPERC’s Sahil Jai Dutta is joined by Dr Sandy Brian Hager (City, University of London) to discuss the political economy of the corporation. He is the author of the book Public Debt, Inequality, and Power: The Making of a Modern Debt State (2016) published by University of California Press. The conversation spans across the topics of ownership and the politics of public debt, the power of large banks in the US, and his most recent work exploring what drives long-term shifts in the stock markets in the ‘advanced’ economies
The Political Economy of the Corporation: Sahil Jai Duta Interviews Sandy Brian Hager
No full textPERC’s Sahil Jai Dutta is joined by Dr Sandy Brian Hager (City, University of London) to discuss the political economy of the corporation. He is the author of the book Public Debt, Inequality, and Power: The Making of a Modern Debt State (2016) published by University of California Press. The conversation spans across the topics of ownership and the politics of public debt, the power of large banks in the US, and his most recent work exploring what drives long-term shifts in the stock markets in the ‘advanced’ economies
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