Characterisations of finite egglike inversive planes

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An estimate of the stratospheric contribution to springtime tropospheric ozone maxima using TOPSE measurements and beryllium-7 simulations

Measurements of tropospheric ozone (O3) between 30°N and 70°N show springtime maxima at remote locations. The contribution of seasonal changes in stratosphere–troposphere exchange (STE) to these maxima was investigated using measurements from the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) campaign and the beryllium-7 (7Be) distribution from a calculation driven by fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS). Comparison with TOPSE measurements revealed that upper tropospheric model-calculated 7Be mixing ratios were reasonable (a change from previous calculations) but that lower tropospheric mixing ratios were too low most likely due to an overestimation of scavenging. Temporal fluctuations were well captured although their amplitudes were often underestimated. Analysis of O3measurements indicated that O3 mixing ratios increased by 5–10% month−1 for θ \u3c 300 K (the underworld) and by 10–15% month−1 for θ \u3e 300 K (the tropospheric middleworld). 7Be mixing ratios decreased with time for θ \u3c 290 K and increased with time for θ \u3e 300 K. Model-calculated middleworld increases of 7Be were a factor of 2 less than measured increases. 7Be with a stratospheric source (strat-7Be) increased by 4.6–8.8% month−1 along TOPSE flight paths within the tropospheric middleworld. Increases in strat-7Be were not seen along TOPSE flight paths in the underworld. Assuming changes in tropospheric O3 with a stratospheric source are the same as changes in strat-7Be and that 50% of O3 in the region of interest is produced in the stratosphere, changes in STE explain 20–60% of O3 increases in the tropospheric middleworld and less than 33% of O3 increases in the underworld

Developmentally regulated alterations in Polycomb repressive complex 1 proteins on the inactive X chromosome

Polycomb group (PcG) proteins belonging to the polycomb (Pc) repressive complexes 1 and 2 (PRC1 and PRC2) maintain homeotic gene silencing. In Drosophila, PRC2 methylates histone H3 on lysine 27, and this epigenetic mark facilitates recruitment of PRC1. Mouse PRC2 (mPRC2) has been implicated in X inactivation, as mPRC2 proteins transiently accumulate on the inactive X chromosome (Xi) at the onset of X inactivation to methylate histone H3 lysine 27 (H3-K27). In this study, we demonstrate that mPRC1 proteins localize to the Xi, and that different mPRC1 proteins accumulate on the Xi during initiation and maintenance of X inactivation in embryonic cells. The Xi accumulation of mPRC1 proteins requires Xist RNA and is not solely regulated by the presence of H3-K27 methylation, as not all cells that exhibit this epigenetic mark on the Xi show Xi enrichment of mPRC1 proteins. Our results implicate mPRC1 in X inactivation and suggest that the regulated assembly of PcG protein complexes on the Xi contributes to this multistep process

Traditional Owners of the Great Barrier Reef: the next generation of Reef 2050 actions

In short, this Report: Confirms that there are two options for progressing the integration of Traditional Owner interests in the Reef 2050 Plan. Option 1 (Business As Usual) represents a continuation of the current approach of Government-based review and refinement of the (now 23) Traditional Owner actions in the Reef 2050 Plan. Option 2 (Towards Genuine Co-governance) represents Government taking a far more negotiated approach at the GBR-wide level (and subsequently down to local scales) that applies the principles of Free Prior and Informed Consent. Based on extensive engagement concerning the aspirations of Traditional Owners and their support organisations across the GBR, the overwhelming stated desire and demand is for genuine partnership in the overarching governance of the Reef and far deeper ownership of, and participation in, its active day to day management (Option 2). There is an unambiguous view that the foundations set in the Reef 2050 Plan (Option 1), while a step in the right direction, simply reflect Traditional Owner aspirations in someone else’s planning. Meanwhile, a consistent message from Traditional Owners, fuelled by their existing and emerging rights in sea country, is that this more passive form of involvement cannot continue into the future; that a genuine form of agreement making and active implementation (from GBR to local scales) must emerge

Strong peoples - strong country: Indigenous heritage monitoring framework summary report

The report titled 'Monitoring Indigenous Heritage within the Reef 2050 Integrated Monitoring and Reporting Program: Final report of the Indigenous Heritage Expert Group' can be viewed through this repository at http://hdl.handle.net/11017/3535This is a summary report of the Strong peoples – Strong country framework, which details information on the framework. The methodology and processes of the expert group are found in, Monitoring Indigenous Heritage within the Reef 2050 Integrated Monitoring and Reporting Program: Final report of the Indigenous Heritage Expert Group (Jarvis, Hill, Buissereth et al. 2019). This summary presents the key elements of the Indigenous heritage monitoring framework for the Great Barrier Reef: Strong peoples – Strong country. It's been extracted from the Indigenous Heritage Expert Group report, which outlines a proposed design for monitoring of the Indigenous heritage theme under the Reef 2050 Integrated Monitoring and Reporting Program

Monitoring the Indigenous heritage within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the Indigenous Heritage Expert Group

An accessible copy of this report is not yet available from this repository, please contact [email protected] for more information

Scaling relations of metallicity, stellar mass, and star formation rate in metal-poor starbursts: II. Theoretical models

Scaling relations of metallicity (O/H), star formation rate (SFR), and stellar mass give important insight on galaxy evolution. They are obeyed by most galaxies in the Local Universe and also at high redshift. In a companion paper, we compiled a sample of ~1100 galaxies from redshift 0 to ~3, spanning almost two orders of magnitude in metal abundance, a factor of $\sim10^6$ in SFR, and of ~10^5 in stellar mass. We have characterized empirically the star-formation "main sequence" (SFMS) and the mass-metallicity relation (MZR) for this sample, and also identified a class of low-metallicity starbursts, rare locally but more common in the distant universe. These galaxies deviate significantly from the main scaling relations, with high SFR and low metal content for a given M*. In this paper, we model the scaling relations and explain these deviations from them with a set of multi-phase chemical evolution models based on the idea that, independently of redshift, initial physical conditions in a galaxy's evolutionary history can dictate its location in the scaling relations. Our models are able to successfully reproduce the O/H, M*, and SFR scaling relations up to z~3, and also successfully predict the molecular cloud fraction as a function of stellar mass. These results suggest that the scaling relations are defined by different modes of star formation: an "active" starburst mode, more common at high redshift, and a quiescent "passive" mode that is predominant locally and governs the main trends.Comment: 17 pages, 7 figures, accepted for publication by MNRA

Dust Formation In Early Galaxies

We investigate the sources and amount of dust in early galaxies. We discuss dust nucleation in stellar atmospheres using published extended atmosphere models, stellar evolution tracks and nucleation conditions and conclude that the (TPAGB) phase of intermediate mass stars is likely to be the most promising site for dust formation in stellar winds. The implications of chemical evolution models for high redshift galaxies are investigated and we show there is no difficulty in producing dusty galaxies at redshifts above 5 if supernovae are a dominant source of interstellar dust. If dust does not condense efficiently in SNe then significant dust masses can only be generated at by galaxies with a high star formation efficiency. We find the visual optical depth for individual star forming clouds can reach values greater than 1 at very low metallicity (1/100 solar) provided that the mass-radius exponent of molecular clouds is less than two. Most of the radiation from star formation will emerge at IR wavelengths in the early universe provided that dust is present. The (patchy) visual optical depth through a typical early galaxy will however, remain less than 1 on average until a metallicity of 1/10 solar is reached.Comment: in press MNRAS, 17 pages with 19 figs, corrected typo