2,660 research outputs found
Development of vocabulary sophistication across genres in English children's writing
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
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
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
The infrastructural conditions of (de-)growth: The case of the internet
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
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
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
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
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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