7,268 research outputs found

    A daily representation of Great Britain's energy vectors : Natural gas, electricity and transport fuels

    Get PDF
    In much of Europe there is a strong push to decarbonise energy demands, including the largest single end-use demand – heat. Moving heat demands over to the electrical network poses significant challenges and the use of hybrid energy vector and storage systems (heat and electrical storage) will be a critical component in managing this transition. As an example of these challenges (facing many developed countries), the scale of recently available daily energy flows through the UK’s electrical, gas and transport systems are presented. When this data is expressed graphically it illustrates important differences in the demand characteristics of these different vectors; these include the quantity of energy delivered through the networks on a daily basis, and the scale of variability in the gas demand over multiple timescales (seasonal, weekly and daily). As the UK proceeds to migrate heating demands to the electrical network in its drive to cut carbon emissions, electrical demand will significantly increase. Additionally, the greater variability and uncertainty shown in the gas demand will also migrate to the electrical demand posing significant difficulties for the maintenance of a secure and reliable electrical system in the coming decades. The paper concludes an analysis of the different means of accommodating increasingly volatile electricity demands in future energy networks

    Who’s writing open access (OA) articles? Characteristics of OA authors at Ph.D.-granting institutions in the United States

    Get PDF
    The open access (OA) publication movement aims to present research literature to the public at no cost and with no restrictions. While the democratization of access to scholarly literature is a primary focus of the movement, it remains unclear whether OA has uniformly democratized the corpus of freely available research, or whether authors who choose to publish in OA venues represent a particular subset of scholars—those with access to resources enabling them to afford article processing charges (APCs). We investigated the number of OA articles with article processing charges (APC OA) authored by 182,320 scholars with known demographic and institutional characteristics at American research universities across 11 broad fields of study. The results show, in general, that the likelihood for a scholar to author an APC OA article increases with male gender, employment at a prestigious institution (AAU member universities), association with a STEM discipline, greater federal research funding, and more advanced career stage (i.e., higher professorial rank). Participation in APC OA publishing appears to be skewed toward scholars with greater access to resources and job securit

    The structure of Rph, an exoribonuclease from Bacillus anthracis, at 1.7 angstrom resolution

    Get PDF
    Maturation of tRNA precursors into functional tRNA molecules requires trimming of the primary transcript at both the 5' and 3' ends. Cleavage of nucleotides from the 3' stem of tRNA precursors, releasing nucleotide diphosphates, is accomplished in Bacillus by a phosphate-dependent exoribonuclease, Rph. The crystal structure of this enzyme from B. anthracis has been solved by molecular replacement to a resolution of 1.7 angstrom and refined to an R factor of 19.3%. There is one molecule in the asymmetric unit; the crystal packing reveals the assembly of the protein into a hexamer arranged as a trimer of dimers. The structure shows two sulfate ions bound in the active-site pocket, probably mimicking the phosphate substrate and the phosphate of the 3'-terminal nucleotide of the tRNA precursor. Three other bound sulfate ions point to likely RNA-binding sites

    The effect of isokinetic dynamometer deceleration phase on maximum ankle joint range of motion and plantar flexor mechanical properties tested at different angular velocities

    Get PDF
    During range of motion (max-ROM) tests performed on an isokinetic dynamometer, the mechanical delay between the button press (by the participant to signal their max-ROM) and the stopping of joint rotation resulting from system inertia induces errors in both max-ROM and maximum passive joint moment. The present study aimed to quantify these errors by comparing data when max-ROM was obtained from the joint position data, as usual (max-ROMPOS), to data where max-ROM was defined as the first point of dynamometer arm deceleration (max-ROMACC). Fifteen participants performed isokinetic ankle joint max-ROM tests at 5, 30 and 60°·s-1. Max-ROM, peak passive joint moment, end range musculo-articular (MAC) stiffness and area under the joint moment-position curve were calculated. Greater max-ROM was observed in max-ROMPOS than max-ROMACC (P < 0.01) at 5 (0.2 ± 0.15%), 30 (1.8 ± 1.0%) and 60°·s-1 (5.9 ± 2.3%), with the greatest error at the fastest velocity. Peak passive moment was greater and end-range MAC stiffness lower in max-ROMPOS than in max-ROMACC only at 60°·s-1 (P < 0.01), whilst greater elastic energy storage was found at all velocities. Max-ROM and peak passive moment are affected by the delay between button press and eventual stopping of joint rotation in an angular velocity-dependent manner. This affects other variables calculated from the data. When high data accuracy is required, especially at fast joint rotation velocities (≥30°·s-1), max-ROM (and associated measures calculated from joint moment data) should be taken at the point of first change in acceleration rather than at the dynamometer’s ultimate joint position

    Great Britain's Energy Vectors and Transmission Level Energy Storage

    Get PDF
    As an example of the challenges facing many developed countries, the scale of daily energy flows through Great Britain's electrical, gas and transport systems are presented. When this data is expressed graphically it illustrates important differences in the demand characteristics of these different vectors; these include the scale of energy delivered through the networks on a daily basis, and the scale of variability in the different demands over multiple timescales (seasonal, weekly and daily). The paper discusses energy storage in general; the scale of within day stores of energy available to the gas and electrical transmission networks, and suggests Synthetic Natural Gas as an interesting energy carrier that could use existing natural gas infrastructure

    The Impact of Dual Roles in Mentoring Relationships: A Mixed Research Study

    Get PDF
    In the field of counselor education, mentors often are involved in varying roles with mentees, such as being mentor, dissertation chair, and or chair to the mentee. Due to the various roles, both the mentor and mentee need to recognize how each of these roles impacts the development of the mentee and the overall mentoring relationship. The purpose of our study was to examine the relationship between perceived dual roles of the mentor and the impact on the mentoring relationship. We found that counseling students and faculty who had experienced dual roles in their mentoring relationships had high career-related functions than did their counterparts who had not experienced dual mentoring relationships

    Modelling the continental-scale spread of Schmallenberg virus in Europe: Approaches and challenges

    Get PDF
    Following its emergence in northern Europe in 2011 Schmallenberg virus (SBV), a vector-borne disease transmitted by the bites of Culicoides midges, has spread across much of the continent. Here we develop simple models to describe the spread of SBV at a continental scale and, more specifically, within and between NUTS2 regions in Europe. The model for the transmission of SBV between regions suggests that vector dispersal is the principle mechanism for transmission, even at the continental scale. The within-region model indicates that there is substantial heterogeneity amongst regions in the force of infection for cattle and sheep farms. Moreover, there is considerable under-ascertainment of SBV-affected holdings, though the level of under-ascertainment varies between regions. We contrast the relatively simple approach adopted in this study with the more complex continental-scale micro-simulation models which have been developed for pandemic influenza and discuss the strengths, weaknesses and data requirements of both approaches

    Radiation modeling in the Earth and Mars atmospheres using LRO/CRaTER with the EMMREM Module

    Get PDF
    Abstract We expand upon the efforts of Joyce et al. (2013), who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to expectations and are in good agreement with the nearest available measurements and therefore may be used as reasonable estimates for use in efforts in risk assessment in the planning of future space missions as well as in the study of GCRs. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other solar energetic particles measurements) is an online system designed to provide the scientific community with a comprehensive resource on the radiation environments of the inner heliosphere. The data products shown here will be incorporated into PREDICCS in order to further this effort and daily updates will be made available on the PREDICCS website (http://prediccs.sr.unh.edu). Key Points We model GCR dose and dose equivalent rates in Earth and Mars atmospheres Dose rates are in reasonable agreement with nearby measurements Data products will soon be made available on PREDICCS website

    Processing Satellite Data for Slant Total Electron Content Measurements

    Get PDF
    A method, system, and apparatus provide the ability to estimate ionospheric observables using space-borne observations. Space-borne global positioning system (GPS) data of ionospheric delay are obtained from a satellite. The space-borne GPS data are combined with ground-based GPS observations. The combination is utilized in a model to estimate a global three-dimensional (3D) electron density field
    • …
    corecore