2,660 research outputs found

    Development of vocabulary sophistication across genres in English children's writing

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    This is the final version. Available on open access from Springer via the DOI in this record.This paper aims to advance our understanding of how children's use of vocabulary in writing changes as they progress through their school careers. It examines the extent to which a model of lexical sophistication as use of low-frequency, register-appropriate words adequately captures development in vocabulary use across the course of compulsory education in England. We find that the received model needs elaborating in a number of important ways. Specifically: 1) The average frequency of words in the repertoire used by older children is no lower than that of younger children. However, younger children's writing is characterized by extensive repetition of high frequency verbs and adjectives and of low frequency nouns (the latter being a product of a focus on entities which are rarely discussed in adult writing). The role of repetition in this finding implies that lexical sophistication is inseparable from lexical diversity, a construct which is usually treated as distinct. 2) Younger children's writing shows a preference for fiction-like vocabulary over academic-like vocabulary. As they mature, children come to make greater use of academic vocabulary in both their literary and non-literary writing, though this increase is greatest in their nonliterary writing. Use of fiction vocabulary remains constant across year groups but decreases sharply in non- literary writing, showing an enhanced sense of register appropriateness. This development of register appropriate word use can be captured by relatively simple frequencybased measures that could readily be employed by teachers and researchers to track writers' development in this aspect of word use.Economic and Social Research Council (ESRC

    Electron localisation in static and time-dependent one-dimensional model systems

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    Electron localization is the tendency of an electron in a many-body system to exclude other electrons from its vicinity. Using a new natural measure of localization based on the exact manyelectron wavefunction, we find that localization can vary considerably between different ground-state systems, and can also be strongly disrupted, as a function of time, when a system is driven by an applied electric field. We use our new measure to assess the well-known electron localization function (ELF), both in its approximate single-particle form (often applied within density-functional theory) and its full many-particle form. The full ELF always gives an excellent description of localization, but the approximate ELF fails in time-dependent situations, even when the exact Kohn-Sham orbitals are employed.Comment: 7 pages, 4 figure

    Extended conjugated microporous polymers for photocatalytic hydrogen evolution from water

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    Conjugated microporous polymers (CMPs) have been used as photocatalysts for hydrogen production from water in the presence of a sacrificial electron donor. The relative importance of the linker geometry, the co-monomer linker length, and the degree of planarisation were studied with respect to the photocatalytic hydrogen evolution rate

    Chemokines and Viral Infections of the CNS

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    The infrastructural conditions of (de-)growth: The case of the internet

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    Infrastructure studies represent a domain that remains significantly uncharted among degrowth scholars. This is paradoxical considering that infrastructures constitute a fundamental prerequisite for the equitable distribution of many aspects of human well-being that degrowth proponents emphasize. Nonetheless, the substantial resource and energy consumption associated with infrastructures cannot be overlooked. The internet offers an instructive case study in this sense, at its best it forges human connections and is productive of considerable societal value. The resource implications of the often-overlooked internet physical layer of data-centres and submarine cables needs to be acknowledged. Furthermore, the ways in which assumptions of perpetual growth are built into this global infrastructure via the logic layer of internet protocols and other governing mechanisms such as finance and network design need to be examined if we are to determine the extent to which such infrastructures are inherently growth dependent. In making these two arguments, we draw upon the work of both Science and Technology Studies (STS) and Large Technological System (LTS) studies on the inherent problems of large infrastructures which have thus far seen little engagement with questions of degrowth. We review the case of the internet and suggest a number of scenarios that illustrate potential roles for such infrastructures in any planned reduction of economic activity

    Planning, ethics and infrastructural time

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    This paper shows how different properties of time and their ethical implications are reflected in the framing of debates around planning and the perceived problem of delay in the delivery of infrastructure. We examine the way in which plans can take the form of ‘time maps’ that are linear projections of a series of events. This can lead to assumptions that desired futures can only be achieved if the actions that constitute events are performed correctly often coupled with a moral imperative to such performances. It also reflects an orientation towards a more closed view of time that emphasises the significance of ordering such events within a series. This contrasts with a second, more open conception that emphasises the changing, flowing experience of time. Alfred Gell describes these interconnected perspectives as the A- and B-series qualities of time both of which are thick with ethical entanglements. Thus, we use these to set out a framework that applies deontological and consequentialist ethics to the A- and B-series and the tension between delivery and deliberation that exists in infrastructure planning policy to show how different perspectives on time raise different ethical questions

    Evaluation of Surface State Mediated Charge Recombination in Anatase and Rutile TiO2

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    In nanostructured thin films, photogenerated charge carriers can access the surface more easily than in dense films and thus react more readily. However, the high surface area of these films has also been associated with enhanced recombination losses via surface states. We herein use transient absorption spectroscopy to compare the ultrafast charge carrier kinetics in dense and nanostructured TiO2 films for its two most widely used polymorphs: anatase and rutile. We find that nanostructuring does not enhance recombination rates on ultrafast timescales, indicating that surface state mediated recombination is not a key loss pathway for either TiO2 polymorph. Rutile shows faster, and less intensity-dependent recombination than anatase, which we assign to its higher doping density. For both polymorphs, we conclude that bulk rather than surface recombination is the primary determinant of charge carrier lifetime

    From Byte to Bench to Bedside: Molecular Dynamics Simulations and Drug Discovery

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    Molecular dynamics (MD) simulations and computer-aided drug design (CADD) have advanced substantially over the past two decades, thanks to continuous computer hardware and software improvements. Given these advancements, MD simulations are poised to become even more powerful tools for investigating the dynamic interactions between potential small-molecule drugs and their target proteins, with significant implications for pharmacological research.Comment: 15 pages including references, 0 figure

    Solar-Cycle Characteristics Examined in Separate Hemispheres: Phase, Gnevyshev Gap, and Length of Minimum

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    Research results from solar-dynamo models show the northern and southern hemispheres may evolve separately throughout the solar cycle. The observed phase lag between the hemispheres provides information regarding the strength of hemispheric coupling. Using hemispheric sunspot-area and sunspot-number data from Cycles 12 - 23, we determine how out of phase the separate hemispheres are during the rising, maximum, and declining period of each solar cycle. Hemispheric phase differences range from 0 - 11, 0 - 14, and 2 - 19 months for the rising, maximum, and declining periods, respectively. The phases appear randomly distributed between zero months (in phase) and half of the rise (or decline) time of the solar cycle. An analysis of the Gnevyshev gap is conducted to determine if the double-peak is caused by the averaging of two hemispheres that are out of phase. We confirm previous findings that the Gnevyshev gap is a phenomenon that occurs in the separate hemispheres and is not due to a superposition of sunspot indices from hemispheres slightly out of phase. Cross hemispheric coupling could be strongest at solar minimum, when there are large quantities of magnetic flux at the Equator. We search for a correlation between the hemispheric phase difference near the end of the solar cycle and the length of solar-cycle minimum, but found none. Because magnetic flux diffusion across the Equator is a mechanism by which the hemispheres couple, we measured the magnetic flux crossing the Equator by examining magnetograms for Solar Cycles 21 - 23. We find, on average, a surplus of northern hemisphere magnetic flux crossing during the mid-declining phase of each solar cycle. However, we find no correlation between magnitude of magnetic flux crossing the Equator, length of solar minima, and phase lag between the hemispheres.Comment: 15 pages, 7 figure
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