title: Explicit correlation and basis set superposition error: The structure and energy of carbon dioxide dimer

authors: McMahon, Jordan D.

subjects: chemistry

abstract: We have investigated the slipped parallel and t-shaped structures of carbon dioxide dimer [(CO₂)₂] using both conventional and explicitly correlated coupled cluster methods, inclusive and exclusive of counterpoise (CP) correction. We have determined the geometry of both structures with conventional coupled cluster singles doubles and perturbative triples theory [CCSD(T)] and explicitly correlated cluster singles doubles and perturbative triples theory [CCSD(T)-F12b] at the complete basis set (CBS) limits using custom optimization routines. Consistent with previous investigations, we find that the slipped parallel structure corresponds to the global minimum and is 1.09 kJ mol⁻¹ lower in energy. For a given cardinal number, the optimized geometries and interaction energies of (CO₂)₂ obtained with the explicitly correlated CCSD(T)-F12b method are closer to the CBS limit than the corresponding conventional CCSD(T) results. Furthermore, the magnitude of basis set superposition error (BSSE) in the CCSD(T)-F12b optimized geometries and interaction energies is appreciably smaller than the magnitude of BSSE in the conventional CCSD(T) results. We decompose the CCSD(T) and CCSD(T)-F12b interaction energies into the constituent HF or HF CABS, CCSD or CCSD-F12b, and (T) contributions. We find that the complementary auxiliary basis set (CABS) singles correction and the F12b approximation significantly reduce the magnitude of BSSE at the HF and CCSD levels of theory, respectively. For a given cardinal number, we find that non-CP corrected, unscaled triples CCSD(T)-F12b/VXZ-F12 interaction energies are in overall best agreement with the CBS limit.

text: Explicit correlation and basis set superposition error: The structure and energy of carbon dioxide dimer We have investigated the slipped parallel and t-shaped structures of carbon dioxide dimer [(CO₂)₂] using both conventional and explicitly correlated coupled cluster methods, inclusive and exclusive of counterpoise (CP) correction. We have determined the geometry of both structures with conventional coupled cluster singles doubles and perturbative triples theory [CCSD(T)] and explicitly correlated cluster singles doubles and perturbative triples theory [CCSD(T)-F12b] at the complete basis set (CBS) limits using custom optimization routines. Consistent with previous investigations, we find that the slipped parallel structure corresponds to the global minimum and is 1.09 kJ mol⁻¹ lower in energy. For a given cardinal number, the optimized geometries and interaction energies of (CO₂)₂ obtained with the explicitly correlated CCSD(T)-F12b method are closer to the CBS limit than the corresponding conventional CCSD(T) results. Furthermore, the magnitude of basis set superposition error (BSSE) in the CCSD(T)-F12b optimized geometries and interaction energies is appreciably smaller than the magnitude of BSSE in the conventional CCSD(T) results. We decompose the CCSD(T) and CCSD(T)-F12b interaction energies into the constituent HF or HF CABS, CCSD or CCSD-F12b, and (T) contributions. We find that the complementary auxiliary basis set (CABS) singles correction and the F12b approximation significantly reduce the magnitude of BSSE at the HF and CCSD levels of theory, respectively. For a given cardinal number, we find that non-CP corrected, unscaled triples CCSD(T)-F12b/VXZ-F12 interaction energies are in overall best agreement with the CBS limit.

year: 2011

title: Commissioning genetic modification: The marginalisation of dissent in the royal commission on genetic modification

authors: Rogers-Hayden, Tee

abstract: The Royal Commission on Genetic Modification (RCGM) appeared to be a 'public debate'. It sought the participation of people from a cross-section of society according to its broad terms of reference, and invited input on 'options' for the nation. The majority of the public and special interest groups voiced their opposition to Genetic Engineering (GE). Despite this, the Commissioners proposed that Aotearoa New Zealand proceed with GE with 'caution'. (The recommendations included recommencing GE field trials and planning for releases of genetically modified organisms.) 
In this research I applied a multidimensional discourse analysis model to the RCGM to investigate if it was pre-determined in its findings. I analysed the social and historical context of the RCGM, its processes, and the consequential narratives in the texts produced by the environmentalists and the bioproponents who made submissions, and the documentation produced by the RCGM. 
I found that Enlightenment rationality, shaped the context of the Commission and, was reflected in the processes for 'Interested Persons' (the interest groups). This made it difficult for groups to articulate objections to GE that were based on non-scientific, holistic and alternative worldviews. Furthermore, I found that the RCGM's findings reflected the contestation of science evident in the debate between the environmental groups and the bioproponents. The creation of a utopian 'sustainability' discourse by the environmentalists, and their construction of this vision into a tenet called the precautionary principle, confronted the bioproponents' utopian vision of Progress guided by experts using neutral science. The bioproponents' response, to reject the precautionary principle and appropriate and redefine sustainability to mean sustaining Progress through GE, was mirrored in the RCGM' s findings. Thus, modernist rationality shaped the processes of the RCGM, restricting public participation and articulation of opposition to GE, ultimately pre-determining the RCGM in favour of GE.

text: Commissioning genetic modification: The marginalisation of dissent in the royal commission on genetic modification The Royal Commission on Genetic Modification (RCGM) appeared to be a 'public debate'. It sought the participation of people from a cross-section of society according to its broad terms of reference, and invited input on 'options' for the nation. The majority of the public and special interest groups voiced their opposition to Genetic Engineering (GE). Despite this, the Commissioners proposed that Aotearoa New Zealand proceed with GE with 'caution'. (The recommendations included recommencing GE field trials and planning for releases of genetically modified organisms.) 
In this research I applied a multidimensional discourse analysis model to the RCGM to investigate if it was pre-determined in its findings. I analysed the social and historical context of the RCGM, its processes, and the consequential narratives in the texts produced by the environmentalists and the bioproponents who made submissions, and the documentation produced by the RCGM. 
I found that Enlightenment rationality, shaped the context of the Commission and, was reflected in the processes for 'Interested Persons' (the interest groups). This made it difficult for groups to articulate objections to GE that were based on non-scientific, holistic and alternative worldviews. Furthermore, I found that the RCGM's findings reflected the contestation of science evident in the debate between the environmental groups and the bioproponents. The creation of a utopian 'sustainability' discourse by the environmentalists, and their construction of this vision into a tenet called the precautionary principle, confronted the bioproponents' utopian vision of Progress guided by experts using neutral science. The bioproponents' response, to reject the precautionary principle and appropriate and redefine sustainability to mean sustaining Progress through GE, was mirrored in the RCGM' s findings. Thus, modernist rationality shaped the processes of the RCGM, restricting public participation and articulation of opposition to GE, ultimately pre-determining the RCGM in favour of GE.

year: 2004

title: Walking into the past to explore the future: Utulizing larval densities to measure the effects of two climate change factors, temperature and salinity on Poorohe (common smelt, Retropinna retropinna) abundance in Te Puuaha o Waikato

authors: Robcke, Sidney

subjects: Common smelt

abstract: Poorohe (common smelt, Retropinna retropinna) are a highly valued kai species in Te Puuaha o Waikato (the lower 66 km of the Waikato River). Fisher whaanau have observed changes in the amount Poorohe that are harvested during annual fish harvests. Since Poorohe are particularly vulnerable to environmental changes, whaanau are particularly concerned about the how climate change might impact Poorohe populations. Climate change vulnerability assessments (CCVA) currently exist for several native New Zealand fish freshwater species; however, one does not yet exist for Poorohe. Previous larval distribution studies in the lower Waikato River only sampled as far downstream as Tuakau bridge (approximately 45km from the river mouth). These studies indicated that important spawning habitats likely existed downstream of Tuakau bridge. Temperature increases and saltwater intrusion have been identified as two climate change factors that will likely impact Poorohe in Te Puuaha o Waikato, because ambient temperatures have increased since the industrial revolution and the proximity of the study area to the ocean. A literature review was used to explore the experiences of fisher whaanau through the past, present and how the experiences will continue to change in a changing climate. The effects of temperature and saltwater intrusion on Poorohe populations were explored through replicating the methods of past research carried out in the 1980s and 2010s. Current river temperatures are in the optimal temperature range (12°C - 18°C) for Poorohe spawning. The saltwater wedge was suppressed by the high river flow during the eight-week sampling period, and it is unclear whether saltwater intrusion has an impact on Poorohe spawning. Larval densities did not significantly increase down river, which suggests large spawning habitat is not found downstream of Tuakau bridge. Furthermore, there were no decreases in larval densities in the two saltwater sites. This study has contributed to the available literature necessary to develop a CCVA for Poorohe and explored the cultural heritage of traditionally significant practices in Te Puuaha o Waikato relating to Poorohe.

text: Walking into the past to explore the future: Utulizing larval densities to measure the effects of two climate change factors, temperature and salinity on Poorohe (common smelt, Retropinna retropinna) abundance in Te Puuaha o Waikato Poorohe (common smelt, Retropinna retropinna) are a highly valued kai species in Te Puuaha o Waikato (the lower 66 km of the Waikato River). Fisher whaanau have observed changes in the amount Poorohe that are harvested during annual fish harvests. Since Poorohe are particularly vulnerable to environmental changes, whaanau are particularly concerned about the how climate change might impact Poorohe populations. Climate change vulnerability assessments (CCVA) currently exist for several native New Zealand fish freshwater species; however, one does not yet exist for Poorohe. Previous larval distribution studies in the lower Waikato River only sampled as far downstream as Tuakau bridge (approximately 45km from the river mouth). These studies indicated that important spawning habitats likely existed downstream of Tuakau bridge. Temperature increases and saltwater intrusion have been identified as two climate change factors that will likely impact Poorohe in Te Puuaha o Waikato, because ambient temperatures have increased since the industrial revolution and the proximity of the study area to the ocean. A literature review was used to explore the experiences of fisher whaanau through the past, present and how the experiences will continue to change in a changing climate. The effects of temperature and saltwater intrusion on Poorohe populations were explored through replicating the methods of past research carried out in the 1980s and 2010s. Current river temperatures are in the optimal temperature range (12°C - 18°C) for Poorohe spawning. The saltwater wedge was suppressed by the high river flow during the eight-week sampling period, and it is unclear whether saltwater intrusion has an impact on Poorohe spawning. Larval densities did not significantly increase down river, which suggests large spawning habitat is not found downstream of Tuakau bridge. Furthermore, there were no decreases in larval densities in the two saltwater sites. This study has contributed to the available literature necessary to develop a CCVA for Poorohe and explored the cultural heritage of traditionally significant practices in Te Puuaha o Waikato relating to Poorohe.

year: 2024-11-23