title: ¹⁴C marine reservoir variability in herbivores and deposit-feeding gastropods from an open coastline, Papua New Guinea

authors: Petchey, Fiona

subjects: delta-r values

abstract: Herbivorous and deposit-feeding gastropods are a major component of archaeological shell middens worldwide. They provide a wealth of information about subsistence, economy, environment, and climate, but are generally considered to be less than ideal for radiocarbon dating because they can ingest sediment while they graze, inadvertently consuming terrestrial carbon in the process. However, few studies of C-14 activity in herbivores or deposit-feeding gastropods have been conducted into this diverse range of animals that inhabit many environmental niches. Here, we present results investigating ¹⁴C variability in shells belonging to the families Strombidae and Potamididae from the Bogi 1 archaeological site, Caution Bay, southern coastal Papua New Guinea (PNG). These shells make up 39.3% of the shell MNI8 in the excavation units studied and some of these species are the most common taxa of neighboring sites. It would therefore be advantageous to establish if there are any ¹⁴C offsets associated with such animals, and identify those that can give reliable calendar ages. Our methodology combines a high-resolution excavation protocol, selection of short-lived samples identified to species level, and a tri-isotope approach using ¹⁴C, δ¹³C, and delta ¹⁸O to evaluate the source of variability in shells. Our results indicate that considerable variation exists between different species of Strombidae with some inhabiting muddier environments that act as sinks for limestone-derived sediments with depleted ¹⁴C content. The magnitude of variation is, however, overshadowed by that measured in the mudwhelk, Cerithidea largillierti, which has the largest spread in ¹⁴C of any shellfish studied so far at Caution Bay. This animal ingests sediment within the estuary that contains ¹⁴C derived from both enriched and depleted sources.

text: ¹⁴C marine reservoir variability in herbivores and deposit-feeding gastropods from an open coastline, Papua New Guinea Herbivorous and deposit-feeding gastropods are a major component of archaeological shell middens worldwide. They provide a wealth of information about subsistence, economy, environment, and climate, but are generally considered to be less than ideal for radiocarbon dating because they can ingest sediment while they graze, inadvertently consuming terrestrial carbon in the process. However, few studies of C-14 activity in herbivores or deposit-feeding gastropods have been conducted into this diverse range of animals that inhabit many environmental niches. Here, we present results investigating ¹⁴C variability in shells belonging to the families Strombidae and Potamididae from the Bogi 1 archaeological site, Caution Bay, southern coastal Papua New Guinea (PNG). These shells make up 39.3% of the shell MNI8 in the excavation units studied and some of these species are the most common taxa of neighboring sites. It would therefore be advantageous to establish if there are any ¹⁴C offsets associated with such animals, and identify those that can give reliable calendar ages. Our methodology combines a high-resolution excavation protocol, selection of short-lived samples identified to species level, and a tri-isotope approach using ¹⁴C, δ¹³C, and delta ¹⁸O to evaluate the source of variability in shells. Our results indicate that considerable variation exists between different species of Strombidae with some inhabiting muddier environments that act as sinks for limestone-derived sediments with depleted ¹⁴C content. The magnitude of variation is, however, overshadowed by that measured in the mudwhelk, Cerithidea largillierti, which has the largest spread in ¹⁴C of any shellfish studied so far at Caution Bay. This animal ingests sediment within the estuary that contains ¹⁴C derived from both enriched and depleted sources.

year: 2012

title: Melody transcription for interactive applications

authors: McNab, Rodger J.

subjects: computer science

abstract: A melody transcription system has been developed to support interactive music applications. The system accepts monophonic voice input ranging from F2 (87 HZ) to G5 (784 HZ) and tracks the frequency, displaying the result in common music notation. Notes are segmented using adaptive thresholds operating on the signal's amplitude; users are required to separate notes using a stop consonant. The frequency resolution of the system is ±4 cents. Frequencies are internally represented by their distance in cents above MIDI note 0 (8.176 Hz); this allows accurate musical pitch labeling when a note is slightly sharp or flat, and supports a simple method of dynamically adapting the system's tuning to the user's singing. The system was evaluated by transcribing 100 recorded melodies-10 tunes, each sung by 5 male and 5 female singers-comprising approximately 5000 notes. The test data was transcribed in 2.8% of recorded time. Transcription error was 11.4%, with incorrect note segmentation accounting for virtually all errors. Error rate was highly dependent on the singer, with one group of four singers having error rates ranging from 3% to 5%, error over the remaining 6 singers ranged from 11% to 23%.

text: Melody transcription for interactive applications A melody transcription system has been developed to support interactive music applications. The system accepts monophonic voice input ranging from F2 (87 HZ) to G5 (784 HZ) and tracks the frequency, displaying the result in common music notation. Notes are segmented using adaptive thresholds operating on the signal's amplitude; users are required to separate notes using a stop consonant. The frequency resolution of the system is ±4 cents. Frequencies are internally represented by their distance in cents above MIDI note 0 (8.176 Hz); this allows accurate musical pitch labeling when a note is slightly sharp or flat, and supports a simple method of dynamically adapting the system's tuning to the user's singing. The system was evaluated by transcribing 100 recorded melodies-10 tunes, each sung by 5 male and 5 female singers-comprising approximately 5000 notes. The test data was transcribed in 2.8% of recorded time. Transcription error was 11.4%, with incorrect note segmentation accounting for virtually all errors. Error rate was highly dependent on the singer, with one group of four singers having error rates ranging from 3% to 5%, error over the remaining 6 singers ranged from 11% to 23%.

year: 1996-12

title: Weaving kaupapa Māori and e-Learning

authors: Neal, Terry

subjects: New Zealand

abstract: This paper describes the creation and design of an online professional development course that aims to help educators in New Zealand to weave kaupapa Māori and e-Learning approaches together. The team sought to model weaving of kaupapa Māori and e-Learning approaches in how they worked together and the educational design for the material. The authors propose that educators with these skills are crucial if we are to effectively meet the needs of Māori learners, more than that, of all New Zealand learners, in the 21st century.

text: Weaving kaupapa Māori and e-Learning This paper describes the creation and design of an online professional development course that aims to help educators in New Zealand to weave kaupapa Māori and e-Learning approaches together. The team sought to model weaving of kaupapa Māori and e-Learning approaches in how they worked together and the educational design for the material. The authors propose that educators with these skills are crucial if we are to effectively meet the needs of Māori learners, more than that, of all New Zealand learners, in the 21st century.

year: 2006-09