The impact of spin temperature fluctuations on the 21-cm moments

This paper considers the impact of Lyman-alpha coupling and X-ray heating on the 21-cm brightness-temperature one-point statistics (as predicted by semi-numerical simulations). The X-ray production efficiency is varied over four orders of magnitude and the hardness of the X-ray spectrum is varied from that predicted for high-mass X-ray binaries, to the softer spectrum expected from the hot inter-stellar medium. We find peaks in the redshift evolution of both the variance and skewness associated with the efficiency of X-ray production. The amplitude of the variance is also sensitive to the hardness of the X-ray SED. We find that the relative timing of the coupling and heating phases can be inferred from the redshift extent of a plateau that connects a peak in the variance's evolution associated with Lyman-alpha coupling to the heating peak. Importantly, we find that late X-ray heating would seriously hamper our ability to constrain reionization with the variance. Late X-ray heating also qualitatively alters the evolution of the skewness, providing a clean way to constrain such models. If foregrounds can be removed, we find that LOFAR, MWA and PAPER could constrain reionization and late X-ray heating models with the variance. We find that HERA and SKA (phase 1) will be able to constrain both reionization and heating by measuring the variance using foreground-avoidance techniques. If foregrounds can be removed they will also be able to constrain the nature of Lyman-alpha coupling.Comment: 16 pages, 13 figure, 1 table. Accepted for publication in MNRA

Distinguishing models of reionization using future radio observations of 21-cm 1-point statistics

We explore the impact of reionization topology on 21-cm statistics. Four reionization models are presented which emulate large ionized bubbles around over-dense regions (21CMFAST/ global-inside- out), small ionized bubbles in over-dense regions (local-inside-out), large ionized bubbles around under-dense regions (global-outside-in) and small ionized bubbles around under-dense regions (local-outside-in). We show that first-generation instruments might struggle to distinguish global models using the shape of the power spectrum alone. All instruments considered are capable of breaking this degeneracy with the variance, which is higher in outside-in models. Global models can also be distinguished at small scales from a boost in the power spectrum from a positive correlation between the density and neutral-fraction fields in outside-in models. Negative skewness is found to be unique to inside-out models and we find that pre-SKA instruments could detect this feature in maps smoothed to reduce noise errors. The early, mid and late phases of reionization imprint signatures in the brightness-temperature moments, we examine their model dependence and find pre-SKA instruments capable of exploiting these timing constraints in smoothed maps. The dimensional skewness is introduced and is shown to have stronger signatures of the early and mid-phase timing if the inside-out scenario is correct.Comment: 18 pages, 13 figures, updated to agree with published versio

Multi-Cancer Computational Analysis Reveals Metastasis-Associated Variant of Desmoplastic Reaction Involving INHBA and THBS2

Despite extensive research, the details of the metastasis-associated biological mechanisms are largely unknown. Here, we analyze data from multiple cancers using a novel computational method identifying sets of genes whose coordinated overexpression indicates the presence of a particular phenotype. We conclude that there is one shared “core” metastasis-associated gene expression signature corresponding to a specific variant of desmoplastic reaction, present in a large subset of samples that have exceeded a threshold of invasive transition specific to each cancer, indicating that the biological mechanism is triggered at that point. For example this threshold is reached at stage IIIc in ovarian cancer and at stage II in colorectal cancer. It has several features, such as coordinated expression of particular collagens, mainly COL11A1 and other genes, mainly THBS2 and INHBA. The universally prominent presence of INHBA in all cancers strongly suggests a biological mechanism centered on activin A induced TGF-β signaling, because activin A is a member of the TGF-β superfamily consisting of an INHBA homodimer. It is accompanied by the expression of several transcription factors related to epithelial-mesenchymal transition, but not of SNAI1, and expression of E-cadherin is not downregulated. It is reversible, as evidenced by its absence in many matched metastasized samples, but its presence indicates that metastasis has occurred. Therefore, these results can be used for developing high-specificity biomarkers, as well as potential multi-cancer metastasis-inhibiting therapeutics targeting the corresponding biological mechanism

‘Illuminating Colour’ Grosseteste in Glass Part 1

The undertaking of a major exhibition at the National Glass Centre, Sunderland in response to the writings and thinking of Bishop Robert Grosseteste occurred through a collaboration with the Ordered Universe Project and the research interests of Colin Rennie and Dr Cate Watkinson. Several new artworks have been created in response to different texts and concepts that have been drawn out of the manuscripts by the Ordered Universe Project team. These ideas were first explored in the ‘Through a Glass Darkly’ project which generated a series of seminars and meetings between the teams at Durham, Oxford and Sunderland. The intention in making the artworks was to give form to these interactions and discussions, reflecting on interpretations to date and to bring a new perspective and material understanding to Grosseteste’s theories. The creative response started with the premise drawn from Grosseteste’s treatise on colour, De Colore. That is, if colour is light embodied in a diaphanous medium then glass could be used as a metaphor that mediates between light and matter. Through collaborative reading and discussion with the team, the ideas evolved from initial representational approaches to a series of new works that use glass, metal, and digital technologies in tandem to rephrase the ideas in physical form and to open up new dialogues. The resulting works appraise the thinking from individual and collaborative perspectives; a method that Rennie and Watkinson have been successful with in several previous public art projects. The presentation will open up the artistic process and discuss the making of these new artworks through, integration, collaboration and shared knowledge

On Testing the Simulation Theory

Can the theory that reality is a simulation be tested? We investigate this question based on the assumption that if the system performing the simulation is nite (i.e. has limited resources), then to achieve low computational complexity, such a system would, as in a video game, render content (reality) only at the moment that information becomes available for observation by a player and not at the moment of detection by a machine (that would be part of the simulation and whose detection would also be part of the internal computation performed by the Virtual Reality server before rendering content to the player). Guided by this principle we describe conceptual wave/particle duality experiments aimed at testing the simulation theory

Using recorded sounds in the clinical skills lab.

Clinical simulation is embedded in undergraduate nursing education, but does not always reflect real-life situations. As clinical environments are rarely silent, a team of lecturers decided to find out whether background clinical noise could increase authenticity. This article describes how audio recordings were obtained from a variety of settings. Feedback was gathered on the benefits and barriers to widespread implementation.N/

The Ephemeral in Glass Artworks

Transparency and reflection are two fundamental properties of glass and present a wealth of creative potential to the artist and designer. This presentation outlines PhD research that explores these properties, and how they can be manipulated and combined with light to enable ephemeral elements to become an integral part of a glass artwork. These artworks sit predominantly within the field of architectural glass – and are designed to become part of the fabric of a building or urban space. They are created for a particular space, in response to the nature of that space, with the aim of becoming an integral part of an environment, aiding the development of a sense of place for its users. The research explores ways in which architectural glass artworks can combine permanence and physicality with the ephemeral - interacting with transient light and a dynamic environment to embody change and impermanence. Translucent glass acts as a projection screen for shadows, and the reflective glass surface, to a greater or lesser degree, allows the surroundings and people within them to become part of the complex spatial relationships within the artwork. How embodying the ephemeral in artworks can invoke a sense of the ethereal and generate meditative qualities for the viewer also forms part of the research. It will examine the relationships between artwork, environment and the ephemeral in relation to the creation of meditative, spiritual and / or sacred spaces, and wellbeing in general. A survey of new types of glass and coatings on glass being produced for the architectural industry, and in particular how they produce variations in reflectivity and transparency, and the ability to emit light will feed into the research. Documentation of current use of these new types of glass and their application by architects, designers and artists, will place the creation of new artworks in context

Fault systems of the eastern Indonesian triple junction:evaluation of Quaternary activity and implications for seismic hazards

Eastern Indonesia is the site of intense deformation related to convergence between Australia, Eurasia, the Pacific and the Philippine Sea Plate. Analysis of tectonic geomorphology, drainage patterns, exhumed faults and historical seismicity highlights faults that have been active during the Quaternary (Pleistocene to present day), even if instrumental records suggest some are presently inactive. Of twenty-seven largely onshore fault systems studied, eleven show evidence of a maximal tectonic rate, a further five show evidence of rapid tectonic activity. Three faults indicating slow to minimal tectonic rate nonetheless show indications of Quaternary activity, and may simply have long interseismic periods. Although most studied fault systems are highly segmented, many are linked by narrow (<3 km) step-overs to form one or more long, quasi-continuous segments that are capable of producing M >7.5 earthquakes. Sinistral shear across the soft-linked Yapen and Tarera-Aiduna faults and their continuation into the transpressive Seram fold-thrust belt represents perhaps the most active belt of deformation and hence greatest seismic hazard in the region. However, the Palu-Koro Fault, being long, straight and capable of generating supershear ruptures, is considered to represent the greatest seismic risk of all the faults evaluated in this region in view of important strike-slip strands that appear to traverse the thick Quaternary basin fill below Palu city

21-cm signatures of residual HI inside cosmic HII regions during reionization

We investigate the impact of sinks of ionizing radiation on the reionization-era 21-cm signal, focusing on 1-point statistics. We consider sinks in both the intergalactic medium and inside galaxies. At a fixed filling factor of HII regions, sinks will have two main effects on the 21-cm morphology: (i) as inhomogeneous absorbers of ionizing photons they result in smaller and more widespread cosmic HII patches; and (ii) as reservoirs of neutral gas they contribute a non-zero 21-cm signal in otherwise ionized regions. Both effects damp the contrast between neutral and ionized patches during reionization, making detection of the epoch of reionization with 21-cm interferometry more challenging. Here we systematically investigate these effects using the latest semi-numerical simulations. We find that sinks dramatically suppress the peak in the redshift evolution of the variance, corresponding to the midpoint of reionization. As previously predicted, skewness changes sign at midpoint, but the fluctuations in the residual HI suppress a late-time rise. Furthermore, large levels of residual HI dramatically alter the evolution of the variance, skewness and power spectrum from that seen at lower levels. In general, the evolution of the large-scale modes provides a better, cleaner, higher signal-to-noise probe of reionization.Comment: Minor edits to agree with MNRAS published versio

Catalytic and mechanistic studies into the epoxidation of styrenes using manganese complexes of structurally similar polyamine ligands

The synthesis and catalytic activity of manganese(ii) complexes of two polyamine ligands is reported which highlights how a small structural change in the ligand affects the overall catalytic behaviour.</p