title: Punctuated shutdown of Atlantic Meridional Overturning circulation during Greenland Stadial 1

authors: Hogg, Alan G.

abstract: The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runof that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the ‘bipolar seesaw’). Here we exploit sub-fossil New Zealand kauri trees to report the frst securely dated, decadally-resolved atmospheric radiocarbon (¹⁴C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring ¹⁴C records with marine ¹⁴C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric ¹⁴C ofset was close to zero prior to GS-1, before reaching ‘near-modern’ values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but probably due to an equatorward migration of the Polar Front, reducing the advection of southwesterly air masses to high latitudes. Our fndings suggest opposing hemispheric temperature trends were driven by atmospheric teleconnections, rather than AMOC changes.

text: Punctuated shutdown of Atlantic Meridional Overturning circulation during Greenland Stadial 1 The Greenland Stadial 1 (GS-1; ~12.9 to 11.65 kyr cal BP) was a period of North Atlantic cooling, thought to have been initiated by North America fresh water runof that caused a sustained reduction of North Atlantic Meridional Overturning Circulation (AMOC), resulting in an antiphase temperature response between the hemispheres (the ‘bipolar seesaw’). Here we exploit sub-fossil New Zealand kauri trees to report the frst securely dated, decadally-resolved atmospheric radiocarbon (¹⁴C) record spanning GS-1. By precisely aligning Southern and Northern Hemisphere tree-ring ¹⁴C records with marine ¹⁴C sequences we document two relatively short periods of AMOC collapse during the stadial, at ~12,920-12,640 cal BP and 12,050-11,900 cal BP. In addition, our data show that the interhemispheric atmospheric ¹⁴C ofset was close to zero prior to GS-1, before reaching ‘near-modern’ values at ~12,660 cal BP, consistent with synchronous recovery of overturning in both hemispheres and increased Southern Ocean ventilation. Hence, sustained North Atlantic cooling across GS-1 was not driven by a prolonged AMOC reduction but probably due to an equatorward migration of the Polar Front, reducing the advection of southwesterly air masses to high latitudes. Our fndings suggest opposing hemispheric temperature trends were driven by atmospheric teleconnections, rather than AMOC changes.

year: 2016

title: Semantics in Greenstone

authors: Hinze, Annika

subjects: computer science

abstract: This chapter illustrates the impact on a well known digital library system - Greenstone - when it is moved from fixed modules and simple metadatabased structures, to open semantic digital library modules. This change has profound effects on the tools available to end-users to retrieve relevant content from the library, and an equally significant impact on the digital library (DL) architecture. Most current DL systems contain protocols for internal communication that define information exchange solely in terms of searching, browsing, and document retrieval. These communications reflect traditional user interactions in the library. However, this regimented approach results in inflexible systems that are difficult to extend to support other retrieval techniques. Furthermore, simple field-based metadata limits the ability of the DL to connect or disambiguate key items of information, impeding the precision of retrieval.

text: Semantics in Greenstone This chapter illustrates the impact on a well known digital library system - Greenstone - when it is moved from fixed modules and simple metadatabased structures, to open semantic digital library modules. This change has profound effects on the tools available to end-users to retrieve relevant content from the library, and an equally significant impact on the digital library (DL) architecture. Most current DL systems contain protocols for internal communication that define information exchange solely in terms of searching, browsing, and document retrieval. These communications reflect traditional user interactions in the library. However, this regimented approach results in inflexible systems that are difficult to extend to support other retrieval techniques. Furthermore, simple field-based metadata limits the ability of the DL to connect or disambiguate key items of information, impeding the precision of retrieval.

year: 2008

title: He Paiaka Totara: Māori Psychologists Wānanga, report to Ngā Pae o te Māramatanga

authors: Waitoki, Waikaremoana

abstract: Sustainability for the growing number of Māori psychologists depends on a resilient system that reflects the centrality of Māori knowledge, tikanga, kawa and moemoea. Paiaka refers to whakapapa, identity, roots and connectedness. As Māori psychologists how we might use this term with Māori whānau and each other differs according to our own unique skills and abilities - our pūmanawa. (He Paiaka wānanga, August, 29, 2015).

text: He Paiaka Totara: Māori Psychologists Wānanga, report to Ngā Pae o te Māramatanga Sustainability for the growing number of Māori psychologists depends on a resilient system that reflects the centrality of Māori knowledge, tikanga, kawa and moemoea. Paiaka refers to whakapapa, identity, roots and connectedness. As Māori psychologists how we might use this term with Māori whānau and each other differs according to our own unique skills and abilities - our pūmanawa. (He Paiaka wānanga, August, 29, 2015).

year: 2016