title: Redating the earliest evidence of the mid-Holocene relative sea-level highstand in Australia and implications for global sea-level rise.

authors: Dougherty, Amy J.

subjects: Antarctic Regions

abstract: Reconstructing past sea levels can help constrain uncertainties surrounding the rate of change, magnitude, and impacts of the projected increase through the 21st century. Of significance is the mid-Holocene relative sea-level highstand in tectonically stable and remote (far-field) locations from major ice sheets. The east coast of Australia provides an excellent arena in which to investigate changes in relative sea level during the Holocene. Considerable debate surrounds both the peak level and timing of the east coast highstand. The southeast Australian site of Bulli Beach provides the earliest evidence for the establishment of a highstand in the Southern Hemisphere, although questions have been raised about the pretreatment and type of material that was radiocarbon dated for the development of the regional sea-level curve. Here we undertake a detailed morpho- and chronostratigraphic study at Bulli Beach to better constrain the timing of the Holocene highstand in eastern Australia. In contrast to wood and charcoal samples that may provide anomalously old ages, probably due to inbuilt age, we find that short-lived terrestrial plant macrofossils provide a robust chronological framework. Bayesian modelling of the ages provide improved dating of the earliest evidence for a highstand at 6,880±50 cal BP, approximately a millennium later than previously reported. Our results from Bulli now closely align with other sea-level reconstructions along the east coast of Australia, and provide evidence for a synchronous relative sea-level highstand that extends from the Gulf of Carpentaria to Tasmania. Our refined age appears to be coincident with major ice mass loss from Northern Hemisphere and Antarctic ice sheets, supporting previous studies that suggest these may have played a role in the relative sea-level highstand. Further work is now needed to investigate the environmental impacts of regional sea levels, and refine the timing of the subsequent sea-level fall in the Holocene and its influence on coastal evolution.

text: Redating the earliest evidence of the mid-Holocene relative sea-level highstand in Australia and implications for global sea-level rise. Reconstructing past sea levels can help constrain uncertainties surrounding the rate of change, magnitude, and impacts of the projected increase through the 21st century. Of significance is the mid-Holocene relative sea-level highstand in tectonically stable and remote (far-field) locations from major ice sheets. The east coast of Australia provides an excellent arena in which to investigate changes in relative sea level during the Holocene. Considerable debate surrounds both the peak level and timing of the east coast highstand. The southeast Australian site of Bulli Beach provides the earliest evidence for the establishment of a highstand in the Southern Hemisphere, although questions have been raised about the pretreatment and type of material that was radiocarbon dated for the development of the regional sea-level curve. Here we undertake a detailed morpho- and chronostratigraphic study at Bulli Beach to better constrain the timing of the Holocene highstand in eastern Australia. In contrast to wood and charcoal samples that may provide anomalously old ages, probably due to inbuilt age, we find that short-lived terrestrial plant macrofossils provide a robust chronological framework. Bayesian modelling of the ages provide improved dating of the earliest evidence for a highstand at 6,880±50 cal BP, approximately a millennium later than previously reported. Our results from Bulli now closely align with other sea-level reconstructions along the east coast of Australia, and provide evidence for a synchronous relative sea-level highstand that extends from the Gulf of Carpentaria to Tasmania. Our refined age appears to be coincident with major ice mass loss from Northern Hemisphere and Antarctic ice sheets, supporting previous studies that suggest these may have played a role in the relative sea-level highstand. Further work is now needed to investigate the environmental impacts of regional sea levels, and refine the timing of the subsequent sea-level fall in the Holocene and its influence on coastal evolution.

year: 2019

title: Optimisation of bovine embryonic stem cell-like line derivation and candidate gene expression analysis

authors: Reddy, Shobana

abstract: The successful derivation of bovine embryonic stem cells (bESCs) has been an area of interest for livestock scientists over the years. These cells possess significant potential for revolutionising livestock breeding by enabling accelerated genetic gain within a single generation. Although robust derivation methods exist for mouse and human ESCs (mESC, hESC), this is not the case for livestock species. Its derivation remains challenging due to the lack of understanding of signalling pathways that maintain pluripotency and regulate early embryo development in livestock species, along with the failure of direct application of mESC and hESC culture conditions. In recent years, studies have reported the development of culture conditions that support bESC derivation, which were adapted in this thesis. This study aims to optimise bESC culture conditions, as well as optimise quantitative PCR methods for gene expression analysis to assess pluripotency. Using cell enrichment treatments, differential plating, colony picking and cell straining, three bESC-like cell lines were derived, which included a wild-type cell line (17), a red fluorescent reporter cell line (R23), and a transgenic β-κ-casein cell line (B2). Although these cell lines were found to express pluripotency markers, both gene and protein expression analysis revealed that the cell lines comprised of a mixed population. Further validation is required to confirm the identity of the derived cells, including using single cell RNA sequencing, karyotyping, in vitro and in vivo differentiation, whole animal generation, and germline contribution assessment.

text: Optimisation of bovine embryonic stem cell-like line derivation and candidate gene expression analysis The successful derivation of bovine embryonic stem cells (bESCs) has been an area of interest for livestock scientists over the years. These cells possess significant potential for revolutionising livestock breeding by enabling accelerated genetic gain within a single generation. Although robust derivation methods exist for mouse and human ESCs (mESC, hESC), this is not the case for livestock species. Its derivation remains challenging due to the lack of understanding of signalling pathways that maintain pluripotency and regulate early embryo development in livestock species, along with the failure of direct application of mESC and hESC culture conditions. In recent years, studies have reported the development of culture conditions that support bESC derivation, which were adapted in this thesis. This study aims to optimise bESC culture conditions, as well as optimise quantitative PCR methods for gene expression analysis to assess pluripotency. Using cell enrichment treatments, differential plating, colony picking and cell straining, three bESC-like cell lines were derived, which included a wild-type cell line (17), a red fluorescent reporter cell line (R23), and a transgenic β-κ-casein cell line (B2). Although these cell lines were found to express pluripotency markers, both gene and protein expression analysis revealed that the cell lines comprised of a mixed population. Further validation is required to confirm the identity of the derived cells, including using single cell RNA sequencing, karyotyping, in vitro and in vivo differentiation, whole animal generation, and germline contribution assessment.

year: 2025

title: Mental health of people of diverse genders and sexualities in Aotearoa/New Zealand: Findings from the New Zealand Mental Health Monitor

authors: Tan, Kyle K. H.

subjects: Science & Technology

abstract: Issues addressed: To examine mental health inequities, and social exclusion and isolation and protective factor differences between people of diverse genders and sexualities (lesbian/gay, bisexual, gender diverse, and takatāpui) and cisgender and heterosexual people in Aotearoa/New Zealand.  Methods: We employed data from the pooled probability sample of 2016 and 2018 New Zealand Mental Health Monitor. The sample comprised of 2,938 people at least 15 years old, of which 93 had diverse gender and sexuality identities. Generalised linear models were used to test for differences in mental health (current and lifetime mental distress, depression, anxiety, self-harm and suicide), social exclusion and isolation, and friend and family support for people of diverse genders and sexualities. We also conducted exploratory linear regression analyses to examine whether mental health difficulties were associated with social exclusion and isolation and friend/family support.  Results: People of diverse genders and sexualities had high rates of mental health difficulties across all variables we examined. For example, people identifying as diverse genders and sexualities had three times the risk of considering self-harm and suicide than their cisgender and heterosexual counterparts (22% vs 5%; RR = 3.12). People of diverse genders and sexualities also scored an average of 6.08 points higher on the 27-point PHQ-9 depression scale when they had experienced social isolation, and 4.01 points higher when they experienced social exclusion. Conclusion: Our results are consistent with current literature on the large mental health inequities faced by people of diverse genders and sexualities.  So what?: Policy makers and healthcare providers in Aotearoa/New Zealand should consider the negative mental health consequences of social exclusion and isolation for people of diverse genders and sexualities.

text: Mental health of people of diverse genders and sexualities in Aotearoa/New Zealand: Findings from the New Zealand Mental Health Monitor Issues addressed: To examine mental health inequities, and social exclusion and isolation and protective factor differences between people of diverse genders and sexualities (lesbian/gay, bisexual, gender diverse, and takatāpui) and cisgender and heterosexual people in Aotearoa/New Zealand.  Methods: We employed data from the pooled probability sample of 2016 and 2018 New Zealand Mental Health Monitor. The sample comprised of 2,938 people at least 15 years old, of which 93 had diverse gender and sexuality identities. Generalised linear models were used to test for differences in mental health (current and lifetime mental distress, depression, anxiety, self-harm and suicide), social exclusion and isolation, and friend and family support for people of diverse genders and sexualities. We also conducted exploratory linear regression analyses to examine whether mental health difficulties were associated with social exclusion and isolation and friend/family support.  Results: People of diverse genders and sexualities had high rates of mental health difficulties across all variables we examined. For example, people identifying as diverse genders and sexualities had three times the risk of considering self-harm and suicide than their cisgender and heterosexual counterparts (22% vs 5%; RR = 3.12). People of diverse genders and sexualities also scored an average of 6.08 points higher on the 27-point PHQ-9 depression scale when they had experienced social isolation, and 4.01 points higher when they experienced social exclusion. Conclusion: Our results are consistent with current literature on the large mental health inequities faced by people of diverse genders and sexualities.  So what?: Policy makers and healthcare providers in Aotearoa/New Zealand should consider the negative mental health consequences of social exclusion and isolation for people of diverse genders and sexualities.

year: 2021-10-03