Exponentially Small Couplings between Twisted Fields of Orbifold String Theories

We investigate the natural occurence of exponentially small couplings in effective field theories deduced from higher dimensional models. We calculate the coupling between twisted fields of the Z_3 Abelian orbifold compactification of the heterotic string. Due to the propagation of massive Kaluza-Klein modes between the fixed points of the orbifold, the massless twisted fields located at these singular points become weakly coupled. The resulting small couplings have an exponential dependence on the mass of the intermediate states and the distance between the fixed points.Comment: 21 pages, 4 figure

Biosensors and biocatalysis for biorefinery and bioremediation

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Matching secretion capacity via translation control

Inducible gene expression systems commonly employed in microbial hosts are mostly composed of molecular components derived from the lactose (lac), arabinose (ara), rhamnose (rha) and tetracycline (tet) operons. These transcription-level control systems have been widely employed in research and industrial-scale protein production, however they are known to exhibit important limitations. These include; all-or-none (digital) expression profiles, stochastic transcriptional bursting, and heterogeneous expression responses at sub-maximal induction conditions. A new paradigm in genetic regulation emerged with the discovery of genetic regulatory elements within the 5’UTR of bacterial mRNA [1]. Upon binding to a specific metabolite, these so-called riboswitches change conformation, permitting differential gene regulation to occur. To allow us to utilize this alternative mechanism of genetic regulation we developed and characterized a novel recombinant expression system, termed RiboTite [2]. The system operates at both the transcriptional and translational level, using standard inducible promoters and translational-ON riboswitches respectively, collectively providing a multi-layered modular genetic circuit controlling both bacteriophage T7 RNA polymerase and recombinant gene(s) of interest [3]. The precise cellular-level tunable expression control afforded by this system offers a number of potential applications in terms of matching cellular expression rate to host synthetic and processing capacity. Here we will report one such application, where we used the RiboTite system to avoid the overload of secYEG translocon in E. coli, permitting expression/secretion attenuation of recombinant proteins into periplasmic space (Figure 1). Utilizing a library of different signal peptides that target the recombinant protein to secYEG, either via the post-translational (SecB/A) or the co-translational (SRP) pathway, we have demonstrated successful attenuation of recombinant protein reaching the periplasm. Finally under fed-batch fermentation conditions the system has been demonstrated to avoid the overload of the host secretion machinery and produce scFv antibody fragments at industrially relevant titers. Please click Additional Files below to see the full abstract

Resource management, plan quality and governance: A report to Government

This Report contains the main findings from FRST-funded research into planning under the Resource Management Act. It includes five sets of interrelated recommendations. These recommendations identify many actions that are essential if Government is serious about achieving its goal of environmental sustainability. Implementation of the recommendations will require a significant increase in expenditure at all levels of the planning hierarchy, but especially central government

At a Crossroads: American Workers Assess Jobs and Economic Security Amid the Race for President

New national Work Trends study finds high level of concern about job security, economy, and that citizens are divided on candidates' ability to address their concerns

Soil-geosynthetic interaction: interface behaviour

Knowledge of soil vs. geosynthetic and geosynthetic vs. geosynthetic interface shear behaviour is of fundamental importance to designers. This paper considers factors influencing measured behaviour, summarizes methods of measurement including specifications, presents data that quantifies variability, details methods for obtaining characteristic interface shear strength parameters for use in design and defines key questions to be answered by engineers. It is shown that the design of direct shear apparatus is the main reason for observed large variability of measured interface strengths from inter-laboratory comparison testing pro-grams. The need to carry out repeat tests at each normal stress is established. The use of global databases of measured interface strengths to inform selection of strength parameters is discouraged. A recommendation is given to use the results of repeatability testing programs to support calculation of characteristic interface strength parameters. Using the example of landfill lining design, guidance is provided on selection of strength parameters in conjunction with relevant factors of safety, consequences of failure, selection of the controlling interface and minimizing interface displacements

Improving Graduate Futures and Employability Through Embedded Industrial Experience

The financial cost to individuals of higher education is now regularly exceeding £50k before maintenance in the UK; consequently, students are more concerned than ever that their degree should offer value for money when they enter the jobs marketplace. Overshadowed by long-term debt, lack of career options and job offerings with low salary, student numbers in the arts, languages, humanities and philosophy areas have suffered compared to most STEM disciplines (Universities UK, 2018). Computer science, I.T. and computing tend to buck this trend (HESA, 2020), and, with a drive toward reskilling the workforce for a more technology-focussed future, this suits Government strategy. However, graduate employers want to hire individuals who are well rounded and have experience; businesses identify that more general workplace experience is key.The subsequent sections describe a level 7 (Master’s) capstone project module, Commercial Development Practice, dedicated to fulfilling these employer requirements by focussing on project processes rather than project products. The practicalities of running this module and considerations that have been key for the successful application of this technique over the 14 years the module has been running are discussed. The curriculum, pedagogic approaches and assessment methods are presented. The evaluation of this approach, which analyses the impact and student experience and perception of the module using data gathered since 2015, has found that participants gain valuable skills, experience and confidence which leads to more employable graduates

Exponentially Small Couplings and the Hierarchy Problem

We propose a stringy mechanism whereby a large hierarchy between symmetry breaking scales is generated. This mechanism is based upon the existence of a fifth dimension compactified on a segment. We focus on a simple supersymmetric model with one massless Higgs field in the 3 of SU(3) and another one in the $\bar 3$ on each four dimensional end-point of the fifth dimension. Along supersymmetric flat directions the gauge symmetry is broken down to SU(2) due to the vacuum expectation value of the Higgs fields on one of the end points. The remaining massless mode on the other end point acquires a potential due to a massive five dimensional state propagating between the end points. This potential breaks the SU(2) symmetry at an exponentially suppressed scale compared to the SU(3) breaking scale. The suppression factor depends exponentially on the mass M of the massive state and the length $\pi R$ of the fifth dimension. For reasonably large values of the length scale R one can achieve a factor of order M_{W}/M_GUT}.Comment: 8 pages, latex, 2 figure

The United Nations Sustainable Development Goals: a setting for Professional and Research skills

This paper considers the use of the United Nations global goals to provide a framework for the teaching of professional and related skills. The main example and case study considered in this paper is from computing; however, much of the approach and many of the issues are applicable to a wide range of subjects, especially in science. Alongside the specific skills attached to sustainability, the paper also considers the broader development of some of the investigative and analytical skills that underpin university research and reflect the need for a research informed curriculum, and the so-called teaching-research nexus. The paper also considers other aspects of the context for graduate skills, including accreditation requirements and employers' expectations; such expectations of graduates frequently include the requirement that students are able to understand and demonstrate a range of non-technical specific issues, topics and skills and issues. This paper describes the use of global challenges to motivate the delivery and engagement with a case study

Genetically encoded biosensors as tools for the up-cycling of aromatic-based feedstocks

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