White Rose Research Online
(13.411 recursos)
Este es el repositorio institucional de tres universidades del Reino Unido (York, Leeds y Sheffield), creado con el apoyo de SHERPA. Proporciona acceso a los artículos de investigación de las instituciones.
Mostrando recursos 1 - 20 de 6.924
1.
Identity, nature and ground - Katzav, J.
What does the qualitative identity of objects consist in? A standard response is that it consists in the possession of properties and relations. If all of an objects properties and relations are specified, all there is to be specified about its qualitative as opposed to its numerical identity will have been specified. Another response adds that kinds, conceived of as an irreducible category of entity, also play a part in fixing the qualitative identities of objects. In what follows, two arguments are offered according to which these views are insufficient. Both lead to the conclusion that the qualitative identities of...
3.
Gaussian-based techniques for quantum propagation from the time-dependent variational principle: Formulation in terms of trajectories of coupled classical and quantum variables - Shalashilin, D.V.; Burghardt, I.
In this article, two coherent-state based methods of quantum propagation, namely, coupled coherent states (CCS) and Gaussian-based multiconfiguration time-dependent Hartree (G-MCTDH), are put on the same formal footing, using a derivation from a variational principle in Lagrangian form. By this approach, oscillations of the classical-like Gaussian parameters and oscillations of the quantum amplitudes are formally treated in an identical fashion. We also suggest a new approach denoted here as coupled coherent states trajectories (CCST), which completes the family of Gaussian-based methods. Using the same formalism for all related techniques allows their systematization and a straightforward comparison of their mathematical structure...
4.
Arbuscular mycorrhizal fungi influence decomposition of, but not plant nutrient capture from, glycine patches in soil - Hodge, A.
The contribution of different arbuscular mycorrhizal fungi (AMF) to nutrient capture from an organic patch, and the subsequent impact on root proliferation was investigated.
Organic patches were created with glycine labelled with 15N and 13C. This allowed decomposition (as 13CO2 release) and uptake of nutrients (as 13C and 15N enrichments in the plant tissues) to be followed. Changes in root responses were followed in situ by the use of minirhizotrons and compared to responses in control (H2O) patches.
Although there were differences in internal colonization and external mycelium production among the three AMF tested, none of the fungi responded to the presence...
5.
The craft consumer: culture, craft and consumption in a postmodern society - Campbell, C.
This article proposes that social scientists should explicitly recognize the existence of consumers who engage in ‘craft consumption’ and, hence, of an additional image of the consumer to set alongside those of ‘the dupe’,‘the rational hero’ and the ‘postmodern identity-seeker’. The term ‘craft’ is used to refer to consumption activity in which the ‘product’ concerned is essentially both ‘made and designed by the same person’ and to which the consumer typically brings skill, knowledge, judgement and passion while being motivated by a desire for self-expression. Such genuine craft consumption is then distinguished from such closely associated practices as ‘personalization’ and...
6.
A New ecotoxicological model to simulate survival of aquatic invertebrates after exposure to fluctuating and sequential pulses of pesticides - Ashauer, R.; Boxall, A.B.A.; Brown, C.D.
Aquatic nontarget organisms are exposed to fluctuating concentrations or sequential pulses of contaminants, so we need to predict effects resulting from such patterns of exposure. We present a process-based model, the Threshold Damage Model (TDM), that links exposure with effects and demonstrate how to simulate the survival of the aquatic invertebrate Gammarus pulex. Based on survival experiments of up to 28 days duration with three patterns of repeated exposure pulses and fluctuating concentrations of two pesticides with contrasting modes of action (pentachlorophenol and chlorpyrifos) we evaluate the new model and compare it to two approaches based on time-weighted averages. Two...
7.
Consumption externalities, production externalities, and efficient capital accumulation under time non-separable preferences. - Turnovsky, S.J.; Monteiro, G.
The effects of consumption and production externalities on economic performance under time non-separable preferences are examined both theoretically and numerically. We show that a consumption externality alone has long-run distortionary effects if and only if labor is supplied elastically. With fixed labor supply, it has only transitional distortionary effects. Production externalities always generate long-run distortions, irrespective of labor supply. The optimal tax structure to correct for the distortions is characterized. We compare the implications of this model with those obtained when the consumption externality is contemporaneous. While some of the long-run effects are robust, there are also important qualitative and...
8.
Population growth in space and time: spatial logistic equations - Law, R.; Murrell, D.J.; Dieckmann, U.
How great an effect does self-generated spatial structure have on logistic population growth? Results are described from an individual-based model (IBM) with spatially localized dispersal and competition, and from a deterministic approximation to the IBM describing the dynamics of the first and second spatial moments. The dynamical system incorporates a novel closure that gives a close approximation to the IBM in the presence of strong spatial structure. Population growth given by the spatial logistic model can differ greatly from that of the nonspatial logistic equation. Numerical simulations show that populations may grow more slowly or more rapidly than would be...
9.
Optimal deterrence with legal defense expenditure - Gravelle, H.; Garoupa, N.
Legal defence expenditure by those accused of a crime reduces their probability of punishment (whether innocent and guilty). We show that there could be more or less crime in a system which permits such expenditure. Because accused may choose a level of defence expenditure which bankrupts them if found guilty, deterrence can decrease when the fine is increased. The unregulated expenditure of innocent and guilty defendants is inefficient. We show that the optimal fine will never bankrupt the dishonest accused but that the honest accused can be bankrupt or left with positive wealth if convicted. We examine policies to regulate...
10.
Very-low-energy electron microscopy of doped semiconductors - El-Gomati, M.M.; Wells, T.C.R.
Imaging of As- and B-doped silicon regions has been performed in a scanning electron microscope operated in the cathode lens mode, with incident electron energies (EP) as low as 15 eV. The doped regions of n+ (As, 2.5×1020 cm–3) and p+ (B, 8×1019 cm–3) on n-type silicon (~1015 cm–3) show distinct contrast with electron energies of about 3 keV. The brightest region is n+ followed by p+, then the n-type substrate. The highest contrast for the p+ and n+ type regions is reached at about EP = 300 and 15 eV, respectively. The contrast mechanisms are explained in terms of...
11.
The equiaxed-banded microstructural transition during low pressure plasma spraying - Baik, K.H.; Grant, P.S.; Cantor, B.
The microstructure of low pressure plasma spray deposited Al–12%Si has been investigated as a function of temperature during spray deposition, concentrating on deposit homogeneity, porosity, microstructure and microhardness. The deposit microstructure was determined by the temperature during spray deposition. Low temperatures promoted inhomogeneous banded microstructures, incorporating partially solidified and unmelted particles, with high levels of intersplat porosity, extended Si solubility in the α-Al matrix, amorphous and nano-sized Si precipitates and relatively high microhardness. High temperatures promoted homogeneous equiaxed microstructures, with low porosity levels, low Si solubility in the α-Al matrix, micro-sized Si precipitates, and relatively low microhardness. The measured critical...
12.
Adoption reform: Managing diversity and delay - Bell, M.; Wilson, K.; Crawshaw, M.
While many aspects of current government policy on adoption are welcome, there is concern that some key issues in the adoption process are not adequately addressed in the Adoption and Children Bill, 2001, and that the use of quantitative targets will not necessarily support the good practice identified. In this article Margaret Bell , Kate Wilson and Marilyn Crawshaw consider, in particular, two areas of difficulty in the selection and preparation process: managing diversity and delay. Their study highlights the need for practitioners to be flexible and open in their approach to shared assessments, and for agencies to have robust...
13.
More questions than answers: the reflections of Maggie Kohime, a virtual librarian in Second Life - Parker, Lyn
Librarians are already in Second Life in considerable numbers; providing reference services, offering tours, building libraries, linking to digital collections and web pages and sharing information. Are these activities
different to our library services in the real world? This paper gives a brief introduction to Second Life, an outline of how one academic librarian has got involved with using it and reviews the issues that have arisen
from a library perspective.
14.
Forms of collaboration & project delivery in Chinese construction markets: the probable emergence of strategic alliances & design-build - Xu, T.J.; Bower, D.; Smith, N.J.
The regulation that allows foreign contractors to qualify as wholly foreign owned 'construction enterprises' has come into effect since Sep 2002, as one of the steps of the Chinese government to honor its World Trade Organization (WTO) commitments. Strategic planning decides project deliveries of a foreign contractor, whereas emerging market of project deliveries may have significant impact on the strategic planning. Based on an electronic-survey covering foreign contractors, clients (foreign investors), and design institutes, design-build delivery has been found prevalent in foreign contractors projects in China. A SWOT analysis of foreign contractors has been conducted. Collaboration with design institutes is...
15.
Intervalley splitting and intersubband transitions in
n-type Si/SiGe quantum wells: pseudopotential vs. effective mass calculation - Valavanis, A.; Ikonic, Z.; Kelsall, R. W.
Intervalley mixing between conduction band states in low-dimensional Si/SiGe heterostructures induces splitting between nominally degenerate energy levels. The symmetric double-valley effective mass approximation (DVEMA) and the empirical pseudopotential method (EPM) are used to find
the electronic states in different types of quantum wells. A reasonably good agreement between the two methods is found, with the former being much faster computationally. Aside from being an oscillatory function of well width, the splitting is found to be almost independent of in-plane
wave vector, and an increasing function of the magnitude of interface gradient. Whilst the model is defined for symmetric envelope potentials, it is...
16.
Solving transportation bi-level programs with differential
evolution - Koh, Andrew
Bi-level programming problems arise in situations
when the decision maker has to take into account the responses
of the users to his decisions. These problems are recognized as
one of the most difficult and challenging problems in
transportation systems management. Several problems within
the transportation literature can be cast in the bi-level
programming framework. At the same time, significant
advances have been made in the deployment of stochastic
heuristics for function optimization. This paper reports on the
use of Differential Evolution (DE) for solving bi-level
programming problems with applications in the field of
transportation planning. After illustrating our solution
algorithm with some mathematical functions, we then apply
this method to two control problems...
17.
Listening and responding? Children's participation in health care within England - Franklin, Anita; Sloper, Patricia
This article examines recent health policy developments in England in relation to childrens rights under Article 12 and 13 of the United Nations Convention on the Rights of the Child (UNCRC). It draws on practice and research literature to explore evidence regarding: childrens participation both within decisions about their own care and concerning the development of health services, their access to mechanisms that allow them a voice, the provision of and need for accessible information, and factors which prevent or facilitate children's participation. This paper does not explore in detail issues concerning childrens consent or competence to participate, for authoritative...
18.
An early Anglo-Saxon bridle-fitting from South
Leckaway, Forfar, Angus, Scotland - Dickinson, T.M.; Fern, C.; Hall, M.A.
[FIRST PARAGRAPH] In February 2003 the Kinnettles Heritage Group made a quite unexpected
find during field-walking at South Leckaway farm near Forfar, Angus (NGR NO 4379
4810): the most northerly example in Britain by about 150 miles of an Anglo-
Saxon object decorated in Salins Style I. It lay isolated and face down on the surface.
A follow-up field-walk at the end of the month confirmed, partly with the aid of a metal
detector, that there were no readily apparent additional pieces of metalwork, associated
structures or burial evidence. The find was reported under the Scottish Treasure
Trove legislation, duly claimed and allocated in June...
19.
Change, change or be exchanged: The discourse of participation and the manufacture of identity - Musson, G.; Duberley, J.
Promoting participation is an accepted and expected component of managerial activity, reflecting current management ideology and practice. This paper explores how one particular group of supervisors, within the same UK manufacturing organization, experience and make sense of participation practices and the role of identity in that process. Our findings show that whilst supervisors may utilize the managerial discourse in formal settings they also draw upon three alternative responses. Thus contrary to much of the literature they do not represent a homogenous or univocal grouping. Our study highlights the importance of the competing bases of identity formation that supervisors draw from,...
20.
Crossmodal links between audition and touch in covert endogenous spatial attention - Lloyd, D.M.; Merat, N.; McGlone, F.; Spence, C.
We report three experiments designed to investigate the nature of any crossmodal links between audition
and touch in sustained endogenous covert spatial attention, using the orthogonal spatial cuing
paradigm. Participants discriminated the elevation (up vs. down) of auditory and tactile targets presented
to either the left or the right of fixation. In Experiment 1, targets were expected on a particular side in just one modality; the results demonstrated that the participants could spatially shift their attention independently in both audition and touch. Experiment 2 demonstrated that when the participants were informed that targets were more likely to be on one side for both...
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