title: Robust radiocarbon dating of wood samples by high-sensitivity liquid scintillation spectroscopy in the 50–70 kyr age range

authors: Hogg, Alan G.

subjects: liquid scintillation

abstract: Although high-sensitivity liquid scintillation (LS) spectroscopy is theoretically capable of producing finite radiocarbon ages in the 50,000- to 70,000-yr range, there is little evidence in the literature that meaningful dates in this time period have been obtained. The pressing need to undertake calibration beyond 26 kyr has resulted in the regular publication of ¹⁴C results in excess of 50 kyr, yet very little effort has been made to demonstrate their accuracy or precision. There is a paucity of systematic studies of the techniques required to produce reliable dates close to background and the methods needed to assess contamination from either in situ sources or laboratory handling and processing. We have studied the requirements for producing accurate and reliable dates beyond 50 kyr. Laboratory procedures include optimization of LS spectrometers to obtain low and stable non-¹⁴C background count rates, use of low-background counting vials, large benzene volumes, long counting times, and preconditioning of vacuum lines. We also discuss the need for multiple analyses of a suitable material containing no original ¹⁴C (background blank) and the application of an appropriate statistical model to compensate for variability in background contamination beyond counting statistics. Accurate and reproducible finite ages >60 kyr are indeed possible by high-sensitivity LS spectroscopy, but require corroborating background blank data to be defensible.

text: Robust radiocarbon dating of wood samples by high-sensitivity liquid scintillation spectroscopy in the 50–70 kyr age range Although high-sensitivity liquid scintillation (LS) spectroscopy is theoretically capable of producing finite radiocarbon ages in the 50,000- to 70,000-yr range, there is little evidence in the literature that meaningful dates in this time period have been obtained. The pressing need to undertake calibration beyond 26 kyr has resulted in the regular publication of ¹⁴C results in excess of 50 kyr, yet very little effort has been made to demonstrate their accuracy or precision. There is a paucity of systematic studies of the techniques required to produce reliable dates close to background and the methods needed to assess contamination from either in situ sources or laboratory handling and processing. We have studied the requirements for producing accurate and reliable dates beyond 50 kyr. Laboratory procedures include optimization of LS spectrometers to obtain low and stable non-¹⁴C background count rates, use of low-background counting vials, large benzene volumes, long counting times, and preconditioning of vacuum lines. We also discuss the need for multiple analyses of a suitable material containing no original ¹⁴C (background blank) and the application of an appropriate statistical model to compensate for variability in background contamination beyond counting statistics. Accurate and reproducible finite ages >60 kyr are indeed possible by high-sensitivity LS spectroscopy, but require corroborating background blank data to be defensible.

year: 2007

title: D-semigroups and constellations

authors: Stokes, Tim E.

subjects: Science & Technology

abstract: In a result generalising the Ehresmann–Schein–Nambooripad Theorem relating inverse semigroups to inductive groupoids, Lawson has shown that Ehresmann semigroups correspond to certain types of ordered (small) categories he calls Ehresmann categories. An important special case of this is the correspondence between two-sided restriction semigroups and what Lawson calls inductive categories. Gould and Hollings obtained a one-sided version of this last result, by establishing a similar correspondence between left restriction semigroups and certain ordered partial algebras they call inductive constellations (a general constellation is a one-sided generalisation of a category). We put this one-sided correspondence into a rather broader setting, at its most general involving left congruence D-semigroups (which need not satisfy any semiadequacy condition) and what we call co-restriction constellations, a finitely axiomatized class of partial algebras. There are ordered and unordered versions of our results. Two special cases have particular interest. One is that the class of left Ehresmann semigroups (the natural one-sided versions of Lawson’s Ehresmann semigroups) corresponds to the class of co-restriction constellations satisfying a suitable semiadequacy condition. The other is that the class of ordered left Ehresmann semigroups (which generalise left restriction semigroups and for which semigroups of binary relations equipped with domain operation and the inclusion order are important examples) corresponds to a class of ordered constellations defined by a straightforward weakening of the inductive constellation axioms.

text: D-semigroups and constellations In a result generalising the Ehresmann–Schein–Nambooripad Theorem relating inverse semigroups to inductive groupoids, Lawson has shown that Ehresmann semigroups correspond to certain types of ordered (small) categories he calls Ehresmann categories. An important special case of this is the correspondence between two-sided restriction semigroups and what Lawson calls inductive categories. Gould and Hollings obtained a one-sided version of this last result, by establishing a similar correspondence between left restriction semigroups and certain ordered partial algebras they call inductive constellations (a general constellation is a one-sided generalisation of a category). We put this one-sided correspondence into a rather broader setting, at its most general involving left congruence D-semigroups (which need not satisfy any semiadequacy condition) and what we call co-restriction constellations, a finitely axiomatized class of partial algebras. There are ordered and unordered versions of our results. Two special cases have particular interest. One is that the class of left Ehresmann semigroups (the natural one-sided versions of Lawson’s Ehresmann semigroups) corresponds to the class of co-restriction constellations satisfying a suitable semiadequacy condition. The other is that the class of ordered left Ehresmann semigroups (which generalise left restriction semigroups and for which semigroups of binary relations equipped with domain operation and the inclusion order are important examples) corresponds to a class of ordered constellations defined by a straightforward weakening of the inductive constellation axioms.

year: 2017

title: Kūkupa, koro, and kai: The use of Māori vocabulary items in New Zealand English children's picture books

authors: Daly, Nicola

subjects: New Zealand

abstract: When a linguistic form from one language is used in another language, such words are known as borrowings or loan words (Crystal 2003: 56). The English language is renowned for its large capacity for borrowing and it has been suggested that the growth in internationalism in recent times has led to people seeking new words to indicate their local identity (Crystal 1995; Crystal 2003). Certainly this is the case of New Zealand English, the most distinctive aspect of which is borrowings from te reo Maori (Deverson 1991). In 1984 Deverson estimated that most New Zealanders have a passive knowledge of at least 40-50 borrowed Maori loan words (Deverson 1984). This figure has been recently revised by Macalister to 70-80 such words (20,-,63.). A study of the frequency of Maori loan words in New Zealand English in New Zealand School Journals of the 1960s and 1990s showed an incidence of around 6 words per 1,000 (Macalister 1999). Kennedy and Yamazaki (1999) also found borrowed Maori words at a rate of 6 per thousand words. Macalister (2006b) has examined the use of Maori loan words in New Zealand English across a 150 year period from 1850-2000. He examined a corpus of a little under five and a half million words from three sources: Newspapers, parliamentary debates and School Journals. Across the three sources there was an increase from 3.29 words per 1,000 in 1850 to 8.8 per thousand in 2000. Macalister lists the reasons for this change as including urbanisation of the Maori population between 1945 and 1975, which created more contact; the changing status of the Maori language with the kOhanga reo movement; the establishment of the Maori Language Commission (Te Taura Whiri i te Reo Maori) and legislation of Maori as an official language of New Zealand in 1987.

text: Kūkupa, koro, and kai: The use of Māori vocabulary items in New Zealand English children's picture books When a linguistic form from one language is used in another language, such words are known as borrowings or loan words (Crystal 2003: 56). The English language is renowned for its large capacity for borrowing and it has been suggested that the growth in internationalism in recent times has led to people seeking new words to indicate their local identity (Crystal 1995; Crystal 2003). Certainly this is the case of New Zealand English, the most distinctive aspect of which is borrowings from te reo Maori (Deverson 1991). In 1984 Deverson estimated that most New Zealanders have a passive knowledge of at least 40-50 borrowed Maori loan words (Deverson 1984). This figure has been recently revised by Macalister to 70-80 such words (20,-,63.). A study of the frequency of Maori loan words in New Zealand English in New Zealand School Journals of the 1960s and 1990s showed an incidence of around 6 words per 1,000 (Macalister 1999). Kennedy and Yamazaki (1999) also found borrowed Maori words at a rate of 6 per thousand words. Macalister (2006b) has examined the use of Maori loan words in New Zealand English across a 150 year period from 1850-2000. He examined a corpus of a little under five and a half million words from three sources: Newspapers, parliamentary debates and School Journals. Across the three sources there was an increase from 3.29 words per 1,000 in 1850 to 8.8 per thousand in 2000. Macalister lists the reasons for this change as including urbanisation of the Maori population between 1945 and 1975, which created more contact; the changing status of the Maori language with the kOhanga reo movement; the establishment of the Maori Language Commission (Te Taura Whiri i te Reo Maori) and legislation of Maori as an official language of New Zealand in 1987.

year: 2007