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Conditions and dynamics of magma storage in the Snæfellsnes volcanic zone, Western Iceland: insights from the Búðahraun and Berserkjahraun eruptions
No full textEstablishing the conditions and dynamics of pre-eruptive magma storage and transfer within transient transcrustal storage networks is a major focus of quantitative volcanic petrology. In Iceland, the behaviour, conditions and timescales of magmatic processes within on-rift plumbing systems are increasingly well constrained. However, relatively little is known about magma storage and transfer in off-rift zones, despite off-rift volcanoes being able to generate hazardous explosive eruptions after centuries or millennia of dormancy (e.g. 2010 AD Eyjafjallajökull; 1362 AD Öræfajökull; 3.0 ka, 4.2 ka and 1104 AD Hekla). We present a combined geochemical and geothermobarometric study of magma storage and transfer recorded in the products of the postglacial Búðahraun (~5.0-8.0 ka) and Berserkjahraun (~4.0 ka) eruptions within the Snæfellsnes volcanic zone. The eruption products contain diverse and compositionally heterogeneous macrocryst cargoes recording complex petrogenetic histories of crystal evolution and inheritance from different parts of the sub-volcanic plumbing systems. Geothermobarometry indicates two compositionally and thermally heterogeneous magma storage regions located in the lower (20±4 km) and upper-mid (11±3 km) crust. Crystallisation pressure and depth estimates coincide with comparable data from Vatnafell, a small sub-glacial table mountain (tuya) in the centre of the Snæfellsnes volcanic zone, indicating that the nature and conditions of magma storage have remained unchanged since the Upper Pleistocene. Trace element zoning of clinopyroxene macrocrysts indicates that mafic recharge into the upper-mid-crustal storage zone triggered the eruptions of Búðahraun and Berserkjahraun. Evidence for eruption-triggering mafic recharge and basaltic cannibalism involving the transfer and amalgamation of crystals with different evolutionary histories sets the Búðahraun and Berserkjahraun eruptions apart from other studied eruptions in Iceland. We propose that the compositional and textural diversity preserved within the crystal cargoes are a direct consequence of the reduced heat flow beneath the Snæfellsnes volcanic zone, which favours the formation of isolated melt pockets in which compositionally diverse macrocryst populations formed. Periodic flushes of primitive basaltic magma from depth promote widespread mixing with evolved melts, resulting in the assembly of crystals with diverse ancestries from different parts of the sub-volcanic systems. Insights gained from the diverse macrocryst cargoes of Búðahraun and Berserkjahraun and comparisons with recent off-rift volcanism in Iceland are essential for the development of future monitoring efforts and hazard evaluation. Although volcanism within the Snæfellsnes volcanic zone differs fundamentally from that in rift zones where eruptions are controlled by extensional spreading, magma ascent from depth still appears to follow pre-existing tectonic escape routes. This could result in extremely short advance warning times on the order of a few days
Low Latency Broadband Internet Satellite Constellations – Technology, Risks and Global Impact
No full textTo achieve global network coverage and meet the demands for high-speed communications, technological improvements have to be made to the existing terrestrial network infrastructure. Low Earth orbit (LEO) satellite constellations have the potential to enable broadband access anywhere in the world and ensure short round-trip delays. This paper investigates the technology behind communication satellite networks in low Earth orbits and estimates the impact that high-speed and widely accessible broadband can have globally. The analytical design of an optimal LEO satellite configuration for continuous global coverage is presented. The results show that in case the users are separated by the orbital seam where the adjacent orbital planes are counter-rotating and inter-satellite links (ISLs) are not supported, the latency is significantly increased. Therefore, polar orbits are necessary to provide global coverage, but show low performance in terms of latency. The optimal solution would be a hybrid constellation: polar orbits to cover high-latitude regions and inclined orbits to meet the data demands in densely populated areas. The presented analyses are used to explore the technology behind communication satellite networks in LEOs and understand their advantages over the existing terrestrial network infrastructure. The crucial part of this paper is the evaluation of risks that LEO satellite networks raise and how, if at all, they can be mitigated. Two main concerns regarding LEO constellations have been investigated – space debris and the effects on astronomical observations. To better understand the severity of the risks, SpaceX’s measures towards risk mitigation are discussed. In summary, the aforementioned risks cannot be eliminated entirely; with today’s technology and the implementation of artificial intelligence, risk mitigation is promising. Nonetheless, the issue of space debris and effects on astronomical observations should not be trivialized. Satellite technology is currently the only way to provide global connectivity and bridge the digital divide. Taking careful mitigating measures, the benefits of such technology outweigh the risks, and in order to bridge the existent digital gap, those trade-offs areultimately worth making
Towards personalised treatment for prostate cancer biology improves image-based data mining models
No full textAutomation and Expansion of EMMA Assembly for Fast-Tracking Mammalian System Engineering
No full textWith applications from functional genomics to the production of therapeutic biologics, libraries of mammalian expression vectors have become a cornerstone of modern biological investigation and engineering. Multiple modular vector platforms facilitate the rapid design and assembly of vectors. However, such systems approach a technical bottleneck when a library of bespoke vectors is required. Utilising the flexibility and robustness of the Extensible Mammalian Modular Assembly toolkit (EMMA), we present an automated work flow for the library-scale design, assembly and verification of mammalian expression vectors. Vector design is simplified using our EMMA computer-aided design tool (EMMA-CAD), whilst the precision and speed of acoustic droplet ejection technology are applied in vector assembly. Our pipeline facilitates significant reductions in both reagent usage and researcher hands-on time when compared with manual assembly, as shown by system Q-metrics. To demonstrate automated EMMA performance, we compiled a library of 48 distinct plasmid vectors, encoding either CRISPR interference or activation modalities. Characterization of work flow parameters shows that high assembly efficiency is maintained across vectors of various sizes and design complexities. Our system also performs strongly when compared to manual assembly efficiency benchmarks. Alongside our automated pipeline, we present a straightforward strategy for integrating gRNA and Cas9 modules into the EMMA platform, enabling the design and manufacture of valuable genome editing resources
A new class of control structures for heterogeneous reactive distillation processes
No full textThere are only a handful of process control structures applied to the neat operation of both homogeneous and heterogeneous reactive distillation, for two-reactants / two-products one reaction systems. All of these control structures employ inferential temperature control (or concentration analyzers) at some location in the column to balance the reaction stoichiometry. This original study proposes a new class of control structures applicable to heterogeneous reactive distillation. The novel idea, common to all control structures, is based on monitoring the inventory of the reactant involved in the heterogeneous azeotrope. The organic reflux (or the organic reflux / aqueous distillate ratio) is used to detect the excess or deficiency of the reactant, based on which the fresh feed rate is adjusted such that the reaction stoichiometry is balanced. This control philosophy is simple and easy to implement in different ways as illustrated by several case studies. The performance of the proposed control structures depends on the system studied. For some systems, the performance is better, as good or nearly as good as that of the literature control structures. But for other systems, the performance is poor or the structure even fails to control the process, due to the insufficient feedback from inventory measurements. <br/
A Syscall-Level Binary-Compatible Unikernel
No full textUnikernels are minimal single-purpose virtual machines. They are highly popular in the research domain due to the benefits they provide. A barrier to their widespread adoption is the difficulty/impossibility to port existing applications to current unikernels. HermiTux is the first unikernel providing system call-level binary compatibility with Linux applications. It is composed of a hypervisor and a lightweight kernel layer emulating the load- and runtime Linux ABI. HermiTux relieves application developers from the burden of porting software, while providing unikernel benefits such as security through hardware-assisted virtualized isolation, swift boot time, and low disk/memory footprint. Fast system calls and kernel modularity are enabled through binary rewriting and analysis techniques, as well as shared library substitution. HermiTux’s design principles are architecture-independent and we present a prototype on both the x86-64 and ARM aarch64 ISAs, targeting various cloud as well as edge/embedded deployments. We demonstrate HermiTux’s compatibility over a range of native C/C++/Fortran/Python Linux applications. We also show that it offers a similar degree of lightweightness compared to other unikernels, and that it performs similarly to Linux in many cases: its performance overhead averages 3% in memory- and compute-bound scenarios, and its I/O performance is acceptable
Corbino FETs in magnetic field: highly tunable photodetectors
No full textWe study gated field effect transistors (FETs) with an eccentric Corbino-disk geometry, such that the drain spans its circumference while the off-center inner ring acts as a source. An AC THz potential difference is applied between source and gate while a static source-drain voltage, rectified by the nonlinearities of FET electrons, is measured. When a magnetic field is applied perpendicular to the device, a strong resonance appears at the cyclotron frequency. The strength of the resonance can be tuned by changing the eccentricity of the disk. We show that there is an optimum value of the eccentricity that maximizes the responsivity of the FET
Treatment outcomes for small cell carcinoma of the bladder: results from a UK patient retrospective cohort study
No full textBackground: Small cell carcinoma of the bladder (SCCB) is rare, accounting for under 1% of all bladder carcinomas. It is aggressive and outcomes are poor due to early metastatic spread. Owing to its rarity, there are limitations on data to propose standardised management pathways. Patients and methods: We conducted a retrospective analysis of patients presenting with pure or predominant histology SCCB to 26 UK institutions between 2006 and 2016. Data cut-off date was 1/2/2018. We report on patient characteristics, treatment received and subsequent clinical outcomes. Results: 409 eligible patients were included. 306 (74.8%) were male, median age was 71 years (range 35-96) and 189 (46.2%) had pure histology SCCB. At data cut-off, 301 patients (73.6%) have died. Median overall survival (OS) was 15.9 (95% confidence interval (CI) 13.2-18.7) months. 200 patients (48.9%), were confirmed to have bladder confined disease (N0 M0), with a median OS of 28.3 (95% CI 20.9-35.8) months, versus 12.7 (95% CI 10.9-14.6) months for 172 (42.1%) patients with confirmed N1-3 and/or M1 disease (hazard ratio 2.03, 95% CI 1.58-2.60, p=<0.001). 247 patients (61.5%) received primary chemotherapy, with a median OS of 21.6 (95% CI 15.5-27.6) months, versus 9.1 (95% CI 5.4-12.8) months in those who did not (HR 0.46, 95%CI 0.37-0.59, p=<0.001). Choice of chemotherapy agent did not alter outcomes. For those with bladder confined disease, 61 patients (30.5%) had cystectomy and 104/200 (52.0%) had radiotherapy. Survival outcomes were similar despite choice of cystectomy or radiotherapy. Only 6 patients (1.5%) were identified to have brain metastases at any time point. Conclusions: This is the largest retrospective study of all stage SCCB to date. Patients have a poor prognosis overall but with improved survival in those able to receive chemotherapy and with organ confined disease. Brain metastases are rare
Switching Polymorph Stabilities with Impurities Provides A Thermodynamic Route to Benzamide Form III
No full textAlmost 200 years ago, benzamide was reported as polymorphic with two of its forms (II and III) found to be of difficult crystallisation. In a recent study, it was shown that benzamide form I can easily convert into benzamide form III with mechanochemistry in the presence of nicotinamide. Here we show, experimentally and computationally, that this transformation is the result of a thermodynamic switch between these two polymorphic forms driven by the formation of solid solutions with small amounts of nicotinamide. The presence of nicotinamide in the crystallisation environment promotes the robust and exclusive crystallisation of the elusive form III. These results represent a promising route to the synthesis andutilisation of elusive polymorphs of pharmaceutical interest