title: Cycloaurated gold(III) complexes with monoanionic thiourea ligands

authors: Smith, Tiffany Sharee

subjects: gold complexes

abstract: Using a simple one-pot procedure, reaction of cycloaurated gold(III) dihalide complexes [LAuCl₂] (L = 2-benzylpyridyl, 2-anilinopyridyl) with trisubstituted thioureas PhNHC(S)NR₂ (R = Me, Cy) and Me3N in methanol, followed by addition of excess NaBPh₄ gave the salts [Lau{SC(-NR₂)NPh}]⁺BPH₄⁻ containing N,S-chelated thiourea monoanion ligands. The compounds were obtained in good yields, and were characterised by ESI MS, elemental microanalysis and in two cases by X-ray structure determinations. The series of complexes was extended by additional microscale reactions of LAuCl₂ complexes (L = 2-benzylpyridyl, 2-anilinopyridyl, 2-benzoylpyridyl or picolinamide) with a wide range of trisubstituted thioureas, with products identified by ESI MS.

text: Cycloaurated gold(III) complexes with monoanionic thiourea ligands Using a simple one-pot procedure, reaction of cycloaurated gold(III) dihalide complexes [LAuCl₂] (L = 2-benzylpyridyl, 2-anilinopyridyl) with trisubstituted thioureas PhNHC(S)NR₂ (R = Me, Cy) and Me3N in methanol, followed by addition of excess NaBPh₄ gave the salts [Lau{SC(-NR₂)NPh}]⁺BPH₄⁻ containing N,S-chelated thiourea monoanion ligands. The compounds were obtained in good yields, and were characterised by ESI MS, elemental microanalysis and in two cases by X-ray structure determinations. The series of complexes was extended by additional microscale reactions of LAuCl₂ complexes (L = 2-benzylpyridyl, 2-anilinopyridyl, 2-benzoylpyridyl or picolinamide) with a wide range of trisubstituted thioureas, with products identified by ESI MS.

year: 2013-11

title: A new attraction-detachment model for explaining flow sliding in clay-rich tephras

authors: Kluger, Max O.

abstract: Altered pyroclastic (tephra) deposits are highly susceptible to landsliding, leading to fatali-ties and property damage every year. Halloysite, a low-activity clay mineral, is commonly associated with landslide-prone layers within altered tephra successions, especially in depos-its with high sensitivity, which describes the post-failure strength loss. However, the precise role of halloysite in the development of sensitivity, and thus in sudden and unpredictable landsliding, is unknown. Here we show that an abundance of mushroom cap–shaped (MCS) spheroidal halloysite governs the development of sensitivity, and hence proneness to landslid-ing, in altered rhyolitic tephras, North Island, New Zealand. We found that a highly sensitive layer, which was involved in a flow slide, has a remarkably high content of aggregated MCS spheroids with substantial openings on one side. We suggest that short-range electrostatic and van der Waals interactions enabled the MCS spheroids to form interconnected aggre-gates by attraction between the edges of numerous paired silanol and aluminol sheets that are exposed in the openings and the convex silanol faces on the exterior surfaces of adjacent MCS spheroids. If these weak attractions are overcome during slope failure, multiple, weakly attracted MCS spheroids can be separated from one another, and the prevailing repulsion between exterior MCS surfaces results in a low remolded shear strength, a high sensitivity, and a high propensity for flow sliding. The evidence indicates that the attraction-detachment model explains the high sensitivity and contributes to an improved understanding of the mechanisms of flow sliding in sensitive, altered tephras rich in spheroidal halloysite.

text: A new attraction-detachment model for explaining flow sliding in clay-rich tephras Altered pyroclastic (tephra) deposits are highly susceptible to landsliding, leading to fatali-ties and property damage every year. Halloysite, a low-activity clay mineral, is commonly associated with landslide-prone layers within altered tephra successions, especially in depos-its with high sensitivity, which describes the post-failure strength loss. However, the precise role of halloysite in the development of sensitivity, and thus in sudden and unpredictable landsliding, is unknown. Here we show that an abundance of mushroom cap–shaped (MCS) spheroidal halloysite governs the development of sensitivity, and hence proneness to landslid-ing, in altered rhyolitic tephras, North Island, New Zealand. We found that a highly sensitive layer, which was involved in a flow slide, has a remarkably high content of aggregated MCS spheroids with substantial openings on one side. We suggest that short-range electrostatic and van der Waals interactions enabled the MCS spheroids to form interconnected aggre-gates by attraction between the edges of numerous paired silanol and aluminol sheets that are exposed in the openings and the convex silanol faces on the exterior surfaces of adjacent MCS spheroids. If these weak attractions are overcome during slope failure, multiple, weakly attracted MCS spheroids can be separated from one another, and the prevailing repulsion between exterior MCS surfaces results in a low remolded shear strength, a high sensitivity, and a high propensity for flow sliding. The evidence indicates that the attraction-detachment model explains the high sensitivity and contributes to an improved understanding of the mechanisms of flow sliding in sensitive, altered tephras rich in spheroidal halloysite.

year: 2017-02-01

title: Whanau Whakapakari: a Māori-centred approach to child rearing and Parent-training programmes

authors: Herbert, Averil May Lloyd

subjects: Whanau Whakapakari

abstract: The goal of this Whanau Whakapakari (Strengthening Families) research was to define critical aspects of Māori experiences and views on child-rearing practices, and to describe whanau (extended family) values and expectations for tamariki (children) and mokopuna (grandchildren).  Furthermore, these Māori views were included in culturally adapted parent-training programmes.  The overall aim was to devise an approach to emphasise client strengths and provide best outcomes for research participants.  Qualitative aspects included discussing the research processes in the Māori community by acknowledging the roles of whanau, hapu (sub-tribal), and iwi (tribal) structures.  I also identified the importance of pan-tribal and urban Māori groups in the current research.  As the project developed, an ongoing consultation and feedback protocol was established to ensure that Māori views on the research and the written outcomes were recognised.  In-depth interviews with kaumatua (elders), and focus groups with Māori service providers and Māori parents were analysed qualitatively to establish Māori values in child rearing and parenting, and the knowledge and skills that contribute to effective parenting and family functioning.  Values identified from these participants confirmed the central role of whanaungatanga (family connections), whakapapa (genealogy), and awhinatanga (support) for Māori. Two culturally adapted parent-training programmes, the Matuatanga (Parenting) Relationships Model and the Matuatanga Values Model programmes, were developed and compared with a Standard Parent Training programme.  The Matuatanga Relationships Model programme emphasised the importance of child, parent and whanau relationships and interactions.  The Matuatanga Values Model programme emphasised Māori values derived from the qualitative data - whanaungatanga, whakapapa and awhinatanga.  A range of pre- and post-training measures were undertaken to identify acceptable and appropriate measures for quantifying parent-training outcomes.  These included questions on support networks, parent expectations of children, parental self-efficacy, parental self-rating, critical-incident scenarios, and programme evaluation.  While 78 participants attended at least one of the research sessions 22 participants provided pre- and post-training measures for the Whanau Whakapakari programmes.  Results showed that there was a medium effect size improvement across all Standard Parent Training and Matuatanga Model programmes and a statistically significant improvement in the Standard Parent Training and Matuatanga Relationship Model programmes.  There were no statistically significant differences between the outcomes of the different programmes but qualitative differences from evaluation and feedback data were considered in identifying specific skills acquisition, general understanding and enjoyment components in the programmes.  Results from the different measures indicated that parent expectations and critical-incident scenario measures provided the most information on post-training changes.  Analysis of the outcome data with the attendance patterns confirmed the value of parent-training programmes per se and indicated that at least in the short term, parent effectiveness scores continued to improve for participants who continued to attend for more than one programme.  Programme follow-ups considered natural whanau supports in the Māori community and issues of social and cultural validity.  Integration of standard parent-training concepts and cultural concepts suggest a multi-dimensional approach which recognises parenting skills acquisition and cultural validation of whanau concepts relevant to parenting for Māori.

text: Whanau Whakapakari: a Māori-centred approach to child rearing and Parent-training programmes The goal of this Whanau Whakapakari (Strengthening Families) research was to define critical aspects of Māori experiences and views on child-rearing practices, and to describe whanau (extended family) values and expectations for tamariki (children) and mokopuna (grandchildren).  Furthermore, these Māori views were included in culturally adapted parent-training programmes.  The overall aim was to devise an approach to emphasise client strengths and provide best outcomes for research participants.  Qualitative aspects included discussing the research processes in the Māori community by acknowledging the roles of whanau, hapu (sub-tribal), and iwi (tribal) structures.  I also identified the importance of pan-tribal and urban Māori groups in the current research.  As the project developed, an ongoing consultation and feedback protocol was established to ensure that Māori views on the research and the written outcomes were recognised.  In-depth interviews with kaumatua (elders), and focus groups with Māori service providers and Māori parents were analysed qualitatively to establish Māori values in child rearing and parenting, and the knowledge and skills that contribute to effective parenting and family functioning.  Values identified from these participants confirmed the central role of whanaungatanga (family connections), whakapapa (genealogy), and awhinatanga (support) for Māori. Two culturally adapted parent-training programmes, the Matuatanga (Parenting) Relationships Model and the Matuatanga Values Model programmes, were developed and compared with a Standard Parent Training programme.  The Matuatanga Relationships Model programme emphasised the importance of child, parent and whanau relationships and interactions.  The Matuatanga Values Model programme emphasised Māori values derived from the qualitative data - whanaungatanga, whakapapa and awhinatanga.  A range of pre- and post-training measures were undertaken to identify acceptable and appropriate measures for quantifying parent-training outcomes.  These included questions on support networks, parent expectations of children, parental self-efficacy, parental self-rating, critical-incident scenarios, and programme evaluation.  While 78 participants attended at least one of the research sessions 22 participants provided pre- and post-training measures for the Whanau Whakapakari programmes.  Results showed that there was a medium effect size improvement across all Standard Parent Training and Matuatanga Model programmes and a statistically significant improvement in the Standard Parent Training and Matuatanga Relationship Model programmes.  There were no statistically significant differences between the outcomes of the different programmes but qualitative differences from evaluation and feedback data were considered in identifying specific skills acquisition, general understanding and enjoyment components in the programmes.  Results from the different measures indicated that parent expectations and critical-incident scenario measures provided the most information on post-training changes.  Analysis of the outcome data with the attendance patterns confirmed the value of parent-training programmes per se and indicated that at least in the short term, parent effectiveness scores continued to improve for participants who continued to attend for more than one programme.  Programme follow-ups considered natural whanau supports in the Māori community and issues of social and cultural validity.  Integration of standard parent-training concepts and cultural concepts suggest a multi-dimensional approach which recognises parenting skills acquisition and cultural validation of whanau concepts relevant to parenting for Māori.

year: 2001