1,264 research outputs found

    Gravitational Aharonov-Bohm Effect

    Full text link
    We investigate the gravitational Aharonov-Bohm effect, by placing a quantum system in free-fall around a gravitating body {\it e.g.} a satellite orbiting the Earth. Since the system is in free-fall, by the equivalence principle, the quantum system is locally in flat, gravity-free space-time - it is screened from the gravitational field. For a slightly elliptical orbit, the gravitational potential will change with time. This leads to the energy levels of the quantum system developing side bands which is the signature for this version of the Aharonov-Bohm effect. This contrasts with the normal signature of the Aharonov-Bohm effect of shifting of interference fringes

    A design of experiments approach for the rapid formulation of a chemically defined medium for metabolic profiling of industrially important microbes

    Get PDF
    This is the final version. Available on open access from Public Library of Science via the DOI in this recordData Availability: All relevant data are within the manuscript and its Supporting Information files.Geobacillus thermoglucosidans DSM2542 is an industrially important microbe, however the complex nutritional requirements of Geobacilli confound metabolic engineering efforts. Previous studies have utilised semi-defined media recipes that contain complex, undefined, biologically derived nutrients which have unknown ingredients that cannot be quantified during metabolic profiling. This study used design of experiments to investigate how individual nutrients and interactions between these nutrients contribute to growth. A mathematically derived defined medium has been formulated that has been shown to robustly support growth of G. thermoglucosidans in two different environmental conditions (96-well plate and shake flask) and with a variety of lignocellulose-based carbohydrates. This enabled the catabolism of industrially relevant carbohydrates to be investigated.Shell Global Solutions BVUniversity of Exete

    Energy level shift of quantum systems via the electric Aharonov-Bohm effect

    Full text link
    A novel version of the electric Aharonov-Bohm effect is proposed where the quantum system which picks up the Aharonov-Bohm phase is confined to a Faraday cage with a time varying, spatially uniform scalar potential. The electric and magnetic fields in this region are effectively zero for the entire period of the experiment. The observable consequence of this version of the electric Aharonov-Bohmn effect is to shift the energy levels of the quantum system rather than shift the fringes of the 2-slit interference pattern. We show a strong mathematical connection between this version of the scalar electric AB effect and the AC Stark effect.Comment: 14 pages revtex, 4 figures. Added references and changes made to address referee comments. To be published in PR

    Rapid, Heuristic Discovery and Design of Promoter Collections in Non-Model Microbes for Industrial Applications

    Get PDF
    This is the author accepted manusript. The final version is available from American Chemical Society via the DOI in this recordAccession Codes: The sequence data for the four Geobacillus spp. used in this study have been submitted to the NCBI Sequence Read Archive and are available under the accession number PRJNA521450.Well-characterized promoter collections for synthetic biology applications are not always available in industrially relevant hosts. We developed a broadly applicable method for promoter identification in atypical microbial hosts that requires no a priori understanding of cis-regulatory element structure. This novel approach combines bioinformatic filtering with rapid empirical characterization to expand the promoter toolkit and uses machine learning to improve the understanding of the relationship between DNA sequence and function. Here, we apply the method in Geobacillus thermoglucosidasius, a thermophilic organism with high potential as a synthetic biology chassis for industrial applications. Bioinformatic screening of G. kaustophilus, G. stearothermophilus, G. thermodenitrificans, and G. thermoglucosidasius resulted in the identification of 636 100 bp putative promoters, encompassing the genome-wide design space and lacking known transcription factor binding sites. Eighty of these sequences were characterized in vivo, and activities covered a 2-log range of predictable expression levels. Seven sequences were shown to function consistently regardless of the downstream coding sequence. Partition modeling identified sequence positions upstream of the canonical -35 and -10 consensus motifs that were predicted to strongly influence regulatory activity in Geobacillus, and artificial neural network and partial least squares regression models were derived to assess if there were a simple, forward, quantitative method for in silico prediction of promoter function. However, the models were insufficiently general to predict pre hoc promoter activity in vivo, most probably as a result of the relatively small size of the training data set compared to the size of the modeled design space

    Exploring the behavioural drivers of veterinary surgeon antibiotic prescribing: a qualitative study of companion animal veterinary surgeons in the UK

    Get PDF
    Background: Multi-drug resistant bacteria are an increasing concern in both human and veterinary medicine. Inappropriate prescribing and use of antibiotics within veterinary medicine may be a contributory factor to antimicrobial resistance (AMR). The ‘One Health’ Initiative aims to work across species and environments to reduce AMR, however; little is currently known about the factors which influence antibiotic prescribing among veterinary surgeons in companion animal practice. This paper reports on qualitative data analysis of interviews with veterinary surgeons whose practice partially or wholly focuses on companion animals (N = 16). The objective of the research was to explore the drivers of companion animal veterinary surgeons’ antibiotic prescribing behaviours. The veterinary surgeons interviewed were all practising within the UK (England (n = 4), Scotland (n = 11), Northern Ireland (n = 1)). A behavioural thematic analysis of the data was undertaken, which identified barriers and facilitators to specific prescribing-related behaviours. Results: Five components of prescribing behaviours were identified: 1) confirming clinical need for antibiotics; 2) responding to clients; 3) confirming diagnosis; 4) determining dose, duration and type of antibiotic; and 5) preventing infection around surgery (with attendant appropriate and inappropriate antibiotic prescribing behaviours). Barriers to appropriate prescribing identified include: business, diagnostic, fear, habitual practice and pharmaceutical factors. Facilitators include: AMR awareness, infection prevention, professional learning and regulation and government factors. Conclusion: This paper uses a behavioural lens to examine drivers which are an influence on veterinary surgeons’ prescribing behaviours. The paper contributes new understandings about factors which influence antibiotic prescribing behaviours among companion animal veterinary surgeons. This analysis provides evidence to inform future interventions, which are focused on changing prescribing behaviours, in order to address the pressing public health concern of AMR

    Two-body Cabibbo-suppressed Decays of Charmed Baryons into Vector Mesons and into Photons

    Get PDF
    The heavy quark effective theory and the factorization approximation are used to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons, ΛCpρ0,pω\Lambda_C\rightarrow p{\rho^0}, p\omega, ΞC+,0Σ+,0ϕ,Σ+,0ρ0,Σ+,0ω\Xi_C^{+,0}\rightarrow\Sigma^{+,0}\phi, \Sigma^{+,0}{\rho^0}, \Sigma^{+,0}\omega and ΞC0Λϕ,Λρ,Λω\Xi_C^{0}\rightarrow\Lambda\phi, \Lambda\rho, \Lambda\omega. The input from two recent experimental results on ΛC\Lambda_C decays allows the estimation of the branching ratios for these modes, which turn out to be between 10410^{-4} and 10310^{-3}. The long distance contribution of these transitions via vector meson dominance to the radiative weak processes ΛCpγ\Lambda_C\rightarrow p\gamma, ΞCΣγ\Xi_C\rightarrow\Sigma\gamma and ΞC0Λγ\Xi_C^0\rightarrow\Lambda\gamma leads to quite small branching ratios, 10610910^{-6}-10^{-9}; the larger value holds if a sum rule between the coupling constants of the vector mesons is broken.Comment: 11 pages, latex, no figure

    Children and young people's mental health outcome measures in paediatrics

    Get PDF
    Paediatricians are increasingly likely to encounter children and young people with mental health difficulties, either as primary presentations or as comorbidities linked with chronic illnesses. However, paediatricians may have limited training or experience regarding the tools available to identify mental health needs and how to use these tools. The current paper aims to provide a go-to guide for paediatricians when considering the use of mental health and well-being outcome measures, including how to select, administer and interpret measures effectively. It also provides practical guidance on the most common mental health outcome measures used in children and young people's mental health services across the UK and elsewhere, which paediatricians are likely to encounter in their practice. Paediatricians may also find these measures useful in their own practice to screen for potential mental health difficulties, monitor the impact of chronic health conditions on a young person's mental health and well-being, or to provide evidence when referring young people to mental health services

    Of Mice and ‘Convicts’: Origin of the Australian House Mouse, Mus musculus

    Get PDF
    The house mouse, Mus musculus, is one of the most ubiquitous invasive species worldwide and in Australia is particularly common and widespread, but where it originally came from is still unknown. Here we investigated this origin through a phylogeographic analysis of mitochondrial DNA sequences (D-loop) comparing mouse populations from Australia with those from the likely regional source area in Western Europe. Our results agree with human historical associations, showing a strong link between Australia and the British Isles. This outcome is of intrinsic and applied interest and helps to validate the colonization history of mice as a proxy for human settlement history

    The antibacterial, anti-biofilm, anti-inflammatory and virulence inhibition properties of Portuguese honeys

    Get PDF
    In Portugal, beekeeping activity has a significant weight among livestock production. The antimicrobial activities of Portuguese honeys have been reported, but the anti-biofilm formation and anti-virulence abilities have not been investigated. The main goal of this work was to study the impact of three monofloral honeys (citrus, lavender and strawberry tree) honeys on adherence of Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Pseudomonas aeruginosa, as well as the influence of the same honeys on virulence using Galleria mellonella as a model. In addition, the general physico-chemical characterization of these honeys and the microbial quality were also performed. The anti-inflammatory activity was also estimated by analyzing the activity of the enzymes hyaluronidase and lipoxygenase. The tested honeys complied with European legislation and no microbial contamination was observed. Of all the honeys at 12.5 and 25%, w/v the citrus honey caused the highest inhibitory activity against P. aeruginosa. Strawberry tree honey at 25% w/v was able to significantly inhibit the MRSA strains. Anti-biofilm formation and anti-inflammatory activities were observed. The different honeys impaired the virulence of S. aureus and MRSA strains. The Portuguese honeys were capable of combating the tested bacterial pathogens not only by inhibiting their growth but also by affecting important pathogenicity properties, such as adherence and virulence
    corecore