Christian Eschatology and the Physical Universe

The scientific picture of the end of the Universe has undergone dramatic changes since 1998, with its future characterized by accelerated expansion and futility. Yet Christian systematic theology has been largely silent on this, despite the interest in eschatology in popular culture and in theology itself. This thesis argues that Christian theology can learn and contribute in a dialogue with the scientific picture of the future of the Universe. Using a Wesleyan approach to theology, the biblical narratives are explored in conversation with the scientific discoveries. If Christian eschatology is to have a fruitful dialogue, then it must take seriously the relationship between creation and new creation. In particular this relationship, modelled by the resurrection, must be represented by a tension between continuity and discontinuity. In this way the movement to new creation is seen as transformation rather than destruction of this creation. Indeed, there are pointers to this new creation which may be part of a revised natural theology. The action and faithfulness of God are both key elements in this transformation, working both in process and event. Contemporary theologians including Mollmann and Pannenberg either ignore this tension or fail to relate it to the physical Universe. At the same time the 'scientific eschatologies' of Dyson and Tipler, and the eschatoiogical speculations of contemporary fundamentalism are shown to be inadequate scientifically and theologically. This tension leads to the suggestion that space and time are real in creation and new creation, and a multidimensional view of God's relationship with time is proposed. Further, speculation on the transformation of matter in new creation needs to reflect its relationality and context. The consequences for the relationship of Christian eschatology to the biological world, providence, hope, ethics, and Christian apologetics are explored. In particular such a robust Christian eschatology engages constructively with questions of hope in contemporary culture

Molecular hydrogen in galaxies

This study aims to understand the key role played by molecular hydrogen in the evolution of galaxies, with a view to constraining its radial distribution in the Galaxy and the CO→H(_2) conversion factor α(_20).The star formation rate is shown to be correlated with the surface density of H(_2). A correlation between the molecular hydrogen fraction and the metallicity of a region allows the time evolution of H(_2) to be described. This leads to a modified 'Schmidt Law' of the SFR which explains quite naturally the production of galactic metallicity gradients and the constancy of the SFR in the absence of infall. A consistent closed model of the chemical evolution of the Galaxy is proposed to solve the G-dwarf problem, the stellar age-metallicity relation and the metallicity gradient, leading to the prediction of some initial amount of pre-disc processing of gas into visible and dark matter. It is found that a constant yield of metals is more appropriate than a yield proportional to metallicity. Possible time variations of the returned fraction, the dark matter fraction and the SFR are also studied. For consistency, we suggest that dark matter in the solar neighbourhood could be totally baryonic provided the Miller-Scalo IMF is modified at the lower end, that is, the dark matter resides in low mass stars or brown dwarfs. The production of metallicity gradients in spiral galaxies is shown to be a direct consequence of the radial variation of the total surface density of matter and the age of the disc. The role of molecular gas in the evolution of the Oort Cloud of comets is examined. It is shown that comet showers with a mean interval of ̴̱ 30My cannot be produced using perturbations of the Oort Cloud by known stars or molecular clouds. If there is indeed an apparent 30My periodicity in the terrestrial mass extinction and geological records, we argue that astronomically induced processes are unlikely to be the primary cause. Evidence is presented that the lifetime of the molecular gas phase is ≤ 2.lO(_8)y, and arguments, particularly from CO observations of the Virgo galaxy cluster, favouring longer lifetimes are shown to be not well founded. We suggest that the ICM in Virgo reduces the value of α(_20) as compared to isolated galaxies. From the above considerations, the radial distribution of in the Galaxy is derived and shown to agree in the inner Galaxy with that derived from ɤ-ray analysis. In the solar neighbourhood we find α(_20) = 2.5±0.5, and present evidence that α(_20) varies as a function of Galactocentric radius and from galaxy to galaxy

NAD+-dependent DNA ligases of Mycobacterium tuberculosis and Streptomyces coelicolor

Sequencing of the genomes of Mycobacterium tuberculosis H37Rv and Streptomyces coelicolor A3(2) identified putative genes for an NAD+-dependent DNA ligase. We have cloned both open reading frames and overexpressed the protein products in Escherichia coli. In vitro biochemical assays confirm that each of these proteins encodes a functional DNA ligase that uses NAD+ as its cofactor. Expression of either protein is able to complement E. coli GR501, which carries a temperature-sensitive mutation in ligA. Thus, in vitro and in vivo analyses confirm predictions that ligA genes from M. tuberculosis and S. coelicolor are NAD+-dependent DNA ligases

The potential of aerosol eDNA sampling for the characterisation of commercial seed lots

<div><p>Seed shipments, silos and storage houses often contain weed seeds or seeds of restricted crops such as undeclared genetically modified (GM) varieties. Random sub-sampling is the favoured approach to detect unwanted biological materials in seed lots but is prohibitively expensive or else ineffective for the huge volumes of seeds moved in commercial operations. This study uses maize and cowpea seed admixtures as an exemplar to evaluate the feasibility of using aerosol sampling of “seed dust” as an alternative to seed sub-sampling. In an initial calibration phase, qPCR of the <i>rbcL</i> barcode followed by high-resolution melting (HRM) of a DNA titration series revealed a strong linear relationship between mix composition and HRM profiles. However, the relationship became skewed when flour mixes were used to build the titration, implying a DNA extraction bias favouring cowpea. Aerosol samples of seed dust above a titration of mixed seed samples were then collected along vertical and lateral axes. Aerosols were characterised by light microscopy, qPCR-HRM and next-generation DNA sequencing (Illumina MiSeq). Both molecular approaches again showed bias but this time in a reverse direction to flour samples. Microscopic examination of the aerosol sample suggested this divergence could be attributed to differences in abundance of airborne starch particles. Despite the bias, it was nevertheless possible to estimate relative abundance of each species using the abundance of minibarcodes. In light of these results we explore the feasibility of aerosol sampling for commercial seed lot characterisation.</p></div

In Vivo Generation of Engraftable Murine Hematopoietic Stem Cells by Gfi1b, c-Fos, and Gata2 Overexpression within Teratoma.

Generation of hematopoietic stem cells (HSCs) from pluripotent stem cells (PSCs) could potentially provide unlimited HSCs for clinical transplantation, a curative treatment for numerous blood diseases. However, to date, bona fide HSC generation has been largely unsuccessful in vitro. We have previously described proof of concept for in vivo HSC generation from PSCs via teratoma formation. However, our first-generation system was complex and the output low. Here, we further optimize this technology and demonstrate the following: (1) simplified HSC generation using transcription factor overexpression; (2) improved HSC output using c-Kit-deficient host mice, and (3) that teratomas can be transplanted and cryopreserved. We demonstrate that overexpression of Gfi1b, c-Fos, and Gata2, previously reported to transdifferentiate fibroblasts into hematopoietic progenitors in vitro, can induce long-term HSC formation in vivo. Our in vivo system provides a useful platform to investigate new strategies and re-evaluate existing strategies to generate HSCs and study HSC development

Characterization of a temperature-sensitive DNA ligase from Escherichia coli

DNA ligases are essential enzymes in cells due to their ability to join DNA strand breaks formed during DNA replication. Several temperature-sensitive mutant strains of Escherichia coli, including strain GR501, have been described which can be complemented by functional DNA ligases. Here, it is shown that the ligA251 mutation in E. coli GR501 strain is a cytosine to thymine transition at base 43, which results in a substitution of leucine by phenylalanine at residue 15. The protein product of this gene (LigA251) is accumulated to a similar level at permissive and non-permissive temperatures. Compared to wild-type LigA, at 20 °C purified LigA251 has 20-fold lower ligation activity in vitro, and its activity is reduced further at 42 °C, resulting in 60-fold lower ligation activity than wild-type LigA. It is proposed that the mutation in LigA251 affects the structure of the N-terminal region of LigA. The resulting decrease in DNA ligase activity at the non-permissive temperature is likely to occur as the result of a conformational change that reduces the rate of adenylation of the ligase

How do we build sustainable e-learning tools to meet the needs of engineering educators?

There are a range of e-learning tools available to current engineering educators to assist in supporting teaching practice. Many of the tools developed previously have been transitory, only existing for the period in which they were funded or failed to be transferable, only adopted by the host institution. Funded e-learning tools are usually expected to have a sustainability plan to ensure ongoing support and adoption, past the life time of the funding, however in practice this is hard to deliver once funding has ended and staff have left. This paper will look at a number of issues which can affect transferability and sustainability including: why academics pilot such tools in the engineering discipline? what consideration is given to sustainability when adopting a new tool or system ? who are the key stakeholders for these resources and why? what factors can encourage a community of users to develop and stay engaged? how can the community of users assist with ongoing sustainability? Particular attention will be given to the experiences and the lessons learnt by the WebPA team in trying to build a community of users, both academic and support staff, around the tool in the search for a sustainable future. By examining the user groups which have developed around the open source WebPA tool the paper will highlight what does and does not work in developing a sustainable community within engineering academia