ORCID Profile
0000-0002-4532-9980
Current Organisation
University of Sydney
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Publisher: Springer Science and Business Media LLC
Date: 21-03-2018
Publisher: Springer Science and Business Media LLC
Date: 24-01-2022
DOI: 10.1038/S41366-022-01068-5
Abstract: To describe trends in overweight/obesity in early childhood for all children and those whose parents are concerned about their weight. To describe parents’ perceptions of their child’s weight and differences by their child’s anthropometric and sociodemographic factors. Analysis of the Kindergarten Health Check, a survey of all children enrolled in their first year of primary education in the Australian Capital Territory. Analysis of detailed data for 2014–2017, including qualitative analysis of parents’ comments on weight, and trends for 2001–2017. 71,963 children participated in the survey between 2001 and 2017 (20,427 between 2014 and 2017). The average age of children (2001–2017) was 5 years and 9.6 months at the time of their physical health check. 2377 children (3.5%) were classified as obese based on measured body mass index (BMI) between 2001 and 2017, and a further 7766 (11.6%) overweight. Similar proportions were seen for 2014–2017. Among children with overweight/obesity in 2014–2017, 86.4% of parents (2479/2868) described their children’s weight as healthy and 13.3% (382/2868) as overweight/obese. Just 11.5% (339/2946) of parents whose children were later measured with overweight/obesity identified having a concern about their child’s weight. Parental comments varied widely and were often incongruent with the known health risks associated with their child’s measured BMI. Comments from parents whose children were measured as obese often were normalising e.g., “ born big, always big. Definitely NOT overweight, just bigger all over” , whilst parents of children in the healthy range expressed concerns about underweight. Parents do not accurately perceive their child’s weight and few document concerns, even among children measuring in the obese BMI category. This lack of concern makes early interventions challenging as parents are in the “pre-contemplative” stage of behaviour change and may see public health c aigns or clinicians’ attempts to address their child’s weight as irrelevant or unhelpful.
Publisher: American Geophysical Union (AGU)
Date: 05-06-2021
DOI: 10.1029/2021GL092570
Abstract: Most of our knowledge of the composition and water content of the cratonic mantle comes from xenoliths found in alkaline magmatic rocks (e.g., kimberlites). However, it is debatable whether such mantle‐xenolith s les are representative of the mantle over larger lateral extents or only represent more local metasomatized conduits. To investigate this, we made 3D deterministic and 1D probabilistic models of magnetotelluric (MT) data from the southwestern Kaapvaal Craton and carried out quantitative interpretations. The results indicate that water content decreases with depth between 100 and 160 km, broadly matching the distribution of metasomatism inferred from garnet‐xenocrysts. Spatially pervasive phlogopite could exist for a colder geotherm (37 mW / m 2 ) whereas it is not required for the more likely geotherm of 40.2 mW / m 2 . Most water contents measured from xenolith s les agree with those calculated from the MT models within error, but the discrepancies between them suggest a local metasomatic control over xenolith water contents.
Publisher: Wiley
Date: 14-09-2021
Publisher: Volcanica
Date: 09-11-2022
DOI: 10.30909/VOL.05.02.349384
Abstract: We present Thermobar, a new open-source Python3 package for calculating pressures, temperatures, and melt compositions from mineral and mineral-melt equilibrium. Thermobar allows users to perform calculations with popular parametrizations involving liquid, olivine-liquid, olivine-spinel, pyroxene only, pyroxene-liquid, two pyroxene, feldspar-liquid, two feldspar, hibole only, hibole-liquid, and garnet equilibria. Thermobar is the first open-source tool which can match up all possible pairs of phases from a given region, and apply various equilibrium tests to identify pairs from which to calculate pressures and temperatures (e.g. pyroxene-liquid, two pyroxene, feldspar-liquid, two feldspar, hibole-liquid). Thermobar also contains functions allowing users to propagate analytical errors using Monte-Carlo methods, convert pressures to depths using different crustal density profiles, plot mineral classification and mineral-melt equilibrium diagrams, calculate liquid viscosities, and convert between oxygen fugacity values, buffer positions and Fe speciation in a silicate melt. Thermobar can be downloaded using pip and extensive documentation is available at thermobar.readthedocs.io/.
Publisher: American Geophysical Union (AGU)
Date: 09-2020
DOI: 10.1029/2020GC009126
Publisher: Elsevier BV
Date: 06-2023
Publisher: Wiley
Date: 09-2021
Publisher: Authorea, Inc.
Date: 17-08-2023
DOI: 10.22541/ESSOAR.169230197.72316079/V1
Abstract: The Northern Tanzanian Divergence in the East Africa Rift is arguably the best place on Earth to study the controls on rifting of thick lithosphere. Here, where the East Africa Rift intersects the Tanzanian Craton and the Mozambique Belt, the relationships between volcanism, faulting, pre-existing structures and lithospheric thickness and composition can be observed. In this work, we carry out the first lithospheric-scale 3D magnetotelluric modelling of the Northern Tanzanian Divergence and combine the results with experimental electrical conductivity and petrology models to calculate mantle composition, which is also inferred in the craton from reanalysis of garnet xenocryst data. Our results show that metasomatic materials exist in the cratonic lithospheric mantle and the relatively undeveloped southern part of the rift zone. However, the lithospheric mantle of the Mozambique Belt and the more developed northern section of the rift is more resistive and does not contain metasomatic phases. Combined with geochemical data from erupted lavas, these results suggest that, in zones that have experienced voluminous Cenozoic magmatism, melting events have destroyed the metasomes and dehydrated the mantle. Since the presence of magma is a primary control of lithospheric strength, rifting may become limited as the lithospheric mantle becomes dehydrated and harder to melt.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Springer Science and Business Media LLC
Date: 15-08-2017
Publisher: American Geophysical Union (AGU)
Date: 03-2022
DOI: 10.1029/2021JB023117
Abstract: The Southern African Magnetotelluric Experiment (SAMTEX) involved the collection of data at over 700 sites in Archean to Proterozoic southern Africa, spanning features including the Kalahari Craton, Bushveld Complex, and voluminous kimberlites. Here, we present the first 3D inversions of the full SAMTEX data set. In this paper, we focus on assessing the robustness of the 3D models by comparing two different inversion codes, jif3D and ModEM , and two different subsets of the data, one containing all acceptable data and the other containing a smaller selection of undistorted, high‐quality data. Results show that the main conductive and resistive features are imaged by all inversions, including deep resistive features in the central Kaapvaal Craton and southern Congo Craton and a lithospheric‐scale conductor beneath the Bushveld Complex. Despite this, differences exist between the jif3D and ModEM inverse models that derive mainly from the differences in regularization between the models, with jif3D producing models that are very smooth laterally and with depth, while ModEM produces models with more discrete conductive and resistive features. Analysis of the differences between these two inversions can provide a good indication of the model resolution. More minor differences are apparent between models run with different subsets of data, with the models containing all acceptable data featuring higher wavelength conductivity variations than those run with fewer stations but also demonstrating poorer data fit.
Publisher: American Geophysical Union (AGU)
Date: 15-09-2022
DOI: 10.1029/2022GL099661
Abstract: Kimberlites are igneous rocks whose formation remains enigmatic due to their severely altered nature, highly variable compositions and rapid ascent through the lithosphere. The spatiotemporal distribution of kimberlites suggests that mantle metasomatism may play an essential role in their emplacement. Since the magnetotelluric (MT) method is sensitive to metasomatic mantle modification in the forms of interconnected minerals and water, we compiled MT models from Australia, Brazil, Botswana, Canada, Namibia, South Africa and the USA, calculated water content variations and compared them to the distribution of kimberlites. Results indicate that kimberlites mostly ascend through hydrated/metasomatized lithosphere and avoid both dry and heavily metasomatized lithosphere. Diamondiferous kimberlites preferentially occur on moderately metasomatized lithosphere, with the diamondiferous rate increasing with the degree of metasomatism in Archean terranes and decreasing in Proterozoic terranes. These results link geophysical observations of mantle metasomatism to kimberlite magmatism and will improve mineral systems models for diamond exploration.
Publisher: American Geophysical Union (AGU)
Date: 03-2022
DOI: 10.1029/2021JB023105
Abstract: The tectonic history of southern Africa includes Archean craton formation, multiple episodes of subduction and rifting and some of the world's most significant magmatic events. These processes left behind a compositional trail that can be observed in xenoliths and measured by geophysical methods. The abundance of kimberlites in southern Africa makes it an ideal place to test and calibrate mantle geophysical interpretations that can then be applied to less well‐constrained regions. Magnetotellurics (MT) is a particularly useful tool for understanding tectonic history because electrical conductivity is sensitive to temperature, bulk composition, accessory minerals, and rock fabric. We produced three‐dimensional MT models of the southern African mantle taken from the SAMTEX MT data set, mapped the properties of ∼36,000 garnet xenocrysts from Group I kimberlites, and compared the results. We found that depleted regions of the mantle are uniformly associated with high electrical resistivities. The conductivity of fertile regions is more complex and depends on the specific tectonic and metasomatic history of the region, including the compositions of metasomatic fluids or melts and the emplacement of metasomatic minerals. The mantle beneath the ∼2.05 Ga Bushveld Complex is highly conductive, probably caused by magmas flowing along a lithospheric weakness zone and precipitating interconnected, conductive accessory minerals such as graphite and sulfides. Kimberlites tend to be emplaced near the edges of the cratons where the mantle below 100 km depth is not highly resistive. Kimberlites avoid strong mantle conductors, suggesting a systematic relationship between their emplacement and mantle composition.
Publisher: American Geophysical Union (AGU)
Date: 07-2019
DOI: 10.1029/2019GC008227
Abstract: Three parameters: temperature, hydrogen content, and the presence of partial melt, are the dominant controls on the rheology of the convecting upper mantle. As such, they determine the dynamics that control plate tectonics and continental evolution. Since hydrogen depresses the peridotite solidus temperature, these parameters are strongly linked petrologically. We have developed a genetic algorithm code to statistically assess the likelihood that a section of upper mantle contains partial melt. This code uses magnetotelluric observations and petrological constraints on composition and solidus temperatures and allows for uncertainties in the geotherm and the electrical conductivity structure. We have applied this code to the convecting upper mantle beneath (1) a stable continent (the Superior Craton) (2) a hot spot (Tristan da Cunha) (3) stable, old oceanic lithosphere (the northwest Pacific Ocean) and (4) young oceanic lithosphere (adjacent to the East Pacific Rise). Results show that the volume of melt in the convecting upper mantle is heterogeneous. The highest melt proportions are beneath the hot spot while little to no melt is required in the other regions. All regions show low water contents (generally wt ppm in olivine) in the shallow convecting upper mantle, making it unlikely that water causes a large or sharp viscosity contrast between the lithosphere and the convecting mantle. Results differ significantly for different experimental olivine hydrogen conductivity models, highlighting the importance of reconciling these experimental constraints.
Publisher: American Association for Cancer Research (AACR)
Date: 31-03-2023
DOI: 10.1158/1078-0432.22479843
Abstract: Supplementary Figure S4. Combination of the BET bromodomain inhibitor I-BET762 and chemotherapy agents, but not proteasome inhibitors, induces cytotoxicity to normal cells.
No related grants have been discovered for Sinan Özaydın.