title: Investigating subantarctic ¹⁴C ages of different peat components: site and sample selection for developing robust age models in dynamic landscapes

authors: Thomas, Zoë

subjects: Science & Technology

abstract: Precise radiocarbon (¹⁴C) dating of sedimentary sequences is important for developing robust chronologies of environmental change, but sampling of suitable components can be challenging in highly dynamic landscapes. Here we investigate radiocarbon determinations of different peat size fractions from six peat sites, representing a range of geomorphological contexts on the South Atlantic subantarctic islands of the Falklands and South Georgia. To investigate the most suitable fraction for dating, 112 measurements were obtained from three components within selected horizons: a fine fraction <0.2 mm, a coarse fraction >0.2 mm, and bulk material. We find site selection is critical, with locations surrounded by high-ground and/or relatively slowly accumulating sites more susceptible to the translocation of older carbon. Importantly, in locations with reduced potential for redeposition of material, our results show that there is no significant or systematic difference between ages derived from bulk material, fine or coarse (plant macrofossil) material, providing confidence in the resulting age model. Crucially, in areas comprising complex terrain with extreme relief, we recommend dating macrofossils or bulk carbon rather than a fine fraction, or employing comprehensive dating of multiple sedimentary fractions to determine the most reliable fraction(s) for developing a robust chronological framework.

text: Investigating subantarctic ¹⁴C ages of different peat components: site and sample selection for developing robust age models in dynamic landscapes Precise radiocarbon (¹⁴C) dating of sedimentary sequences is important for developing robust chronologies of environmental change, but sampling of suitable components can be challenging in highly dynamic landscapes. Here we investigate radiocarbon determinations of different peat size fractions from six peat sites, representing a range of geomorphological contexts on the South Atlantic subantarctic islands of the Falklands and South Georgia. To investigate the most suitable fraction for dating, 112 measurements were obtained from three components within selected horizons: a fine fraction <0.2 mm, a coarse fraction >0.2 mm, and bulk material. We find site selection is critical, with locations surrounded by high-ground and/or relatively slowly accumulating sites more susceptible to the translocation of older carbon. Importantly, in locations with reduced potential for redeposition of material, our results show that there is no significant or systematic difference between ages derived from bulk material, fine or coarse (plant macrofossil) material, providing confidence in the resulting age model. Crucially, in areas comprising complex terrain with extreme relief, we recommend dating macrofossils or bulk carbon rather than a fine fraction, or employing comprehensive dating of multiple sedimentary fractions to determine the most reliable fraction(s) for developing a robust chronological framework.

year: 2019

title: To post or not to post? Perceptions of the use of a closed Facebook group as a networked public space

authors: Ballantyne, Neil

subjects: Facebook

abstract: Members of a closed Facebook group, established to discuss professional social work issues, were surveyed to explore what they valued about the group, the problems or issues associated with membership, and factors associated with participation or reluctance to participate. A non-probability, self-selection sample (N = 53) completed an online survey during January and February 2016. Survey findings suggest that participants valued feeling connected to a community of practice, the ability to post and share information, and access to news and information. However, participants also expressed concern about online incivility and experienced reluctance to post opinions because of concerns about the critical comments of others.

text: To post or not to post? Perceptions of the use of a closed Facebook group as a networked public space Members of a closed Facebook group, established to discuss professional social work issues, were surveyed to explore what they valued about the group, the problems or issues associated with membership, and factors associated with participation or reluctance to participate. A non-probability, self-selection sample (N = 53) completed an online survey during January and February 2016. Survey findings suggest that participants valued feeling connected to a community of practice, the ability to post and share information, and access to news and information. However, participants also expressed concern about online incivility and experienced reluctance to post opinions because of concerns about the critical comments of others.

year: 2017

title: PIWeCS: enhancing human/machine agency in an interactive composition system

authors: Whalley, Ian

abstract: This paper focuses on the infrastructure and aesthetic approach used in PIWeCS: a Public Space Interactive Web-based Composition System. The concern was to increase the sense of dialogue between human and machine agency in an interactive work by adapting Paine's (2002) notion of a conversational model of interaction as a ‘complex system’. The machine implementation of PIWeCS is achieved through integrating intelligent agent programming with MAX/MSP. Human input is through a web infrastructure. The conversation is initiated and continued by participants through arrangements and composition based on short performed samples of traditional New Zealand Maori instruments. The system allows the extension of a composition through the electroacoustic manipulation of the source material.

text: PIWeCS: enhancing human/machine agency in an interactive composition system This paper focuses on the infrastructure and aesthetic approach used in PIWeCS: a Public Space Interactive Web-based Composition System. The concern was to increase the sense of dialogue between human and machine agency in an interactive work by adapting Paine's (2002) notion of a conversational model of interaction as a ‘complex system’. The machine implementation of PIWeCS is achieved through integrating intelligent agent programming with MAX/MSP. Human input is through a web infrastructure. The conversation is initiated and continued by participants through arrangements and composition based on short performed samples of traditional New Zealand Maori instruments. The system allows the extension of a composition through the electroacoustic manipulation of the source material.

year: 2004