1,463 research outputs found
A review of landscape rehabilitation frameworks in ecosystem engineering for mine closure
Mining causes changes to the environment and rehabilitation is necessary at mine closure. There is a lack of appropriate frameworks for mine site rehabilitation. In most cases, restoring the mine to previous conditions
is challenging. Alternatively, mining companies can engineer ecosystems to suit new site conditions and aim for a self-sustaining and resilient ecosystem. In ecosystem design there should be consideration of the four key dimensions of any ecosystem; landscape, function, structure and composition (LFSC). Alcoa’s Bauxite mines and Barrick (Cowal) Limited’s Gold Mine have considered LFSC in their rehabilitation practices. From this, a framework based on LFSC is proposed as a means of planning, undertaking and monitoring
mine rehabilitation, which together aim for a self-sustaining and resilient ecosystem. Elements of this framework are being utilised in the industry, and are supported by research. The framework could be used
as an industry standard, utilised by regulatory bodies and potentially used in conjunction with other models and in other rehabilitation environments
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Portfolio of doctorate in health psychology
Introduction - The purpose of the research was to explore coping and relapse strategies used by pregnant and postpartum women to avoid smoking and to investigate the process of lapses and why this leads to relapse with pregnant and postpartum women. The purpose was to evaluate service delivery by interviewing pregnant and postpartum women. Achieving behaviour change in pregnant women and maintaining cessation in postpartum remains a great challenge in the UK. Gaining a deeper understanding of service delivery may contribute to identification of the active component parts and mediators of successful interventions that elicit behavioural change.
Design - Semi-structured interviews were carried out with fourteen female participants. All of the interviews were conducted in the participant’s home. The interviews lasted between twenty and forty minutes. Participants were six pregnant and eight postpartum clients who had access the service and set a quit date and the age range was from twenty- two to forty-one years of age. The clients were recruited as four distinct samples. The first sample (hereafter referred to as Group 4) consisted of postpartum women who had set a quit date during their pregnancy and had maintain cessation during pregnancy and in the postnatal period. Participants from the second sample (hereafter referred to as Group 3) included pregnant women who had maintained cessation for eight to twelve weeks or longer at any stage during their pregnancy. The third sample (hereafter referred to as Group 1) consisted of postpartum women who had managed to stop smoking during pregnancy and had relapsed back to smoking in the postpartum period within two months. Participants from the last sample (hereafter referred to as Group 2) were pregnant women who had set a quit date at any stage of their pregnancy and relapsed back to smoking.
Results - Twenty themes were identified. Some of the important themes included emotional aspects of smoking, identifying coping strategies, addiction, morals, support, being in control, preparation, adjustment period and postnatal period.
Conclusions - This study has shown that interventions designed to promote cessation during pregnancy and continue postpartum are effective. It has shown how interventions are sensitive to the needs of the pregnant smoker and take into account the psychological and social factors involved with smoking. It has given further insight into the psychological change processes underlying the effectiveness of these interventions and those changes that are important in successful giving up smoking. In addition, it has revealed coping strategies that pregnant and postpartum women utilised to maintain cessation and it explored the journey of lapses to becoming a smoker again and participants’ experiences of service delivery
The nonrelativistic limit of the relativistic point coupling model
We relate the relativistic finite range mean-field model (RMF-FR) to the
point-coupling variant and compare the nonlinear density dependence. From this,
the effective Hamiltonian of the nonlinear point-coupling model in the
nonrelativistic limit is derived. Different from the nonrelativistic models,
the nonlinearity in the relativistic models automatically yields contributions
in the form of a weak density dependence not only in the central potential but
also in the spin-orbit potential. The central potential affects the bulk and
surface properties while the spin-orbit potential is crucial for the shell
structure of finite nuclei. A modification in the Skyrme-Hartree-Fock model
with a density-dependent spin-orbit potential inspired by the point-coupling
model is suggested.Comment: 21 pages, latex, 1 eps figure. accepted for publication in annals of
physic
Combining quantum and classical density functional theory for ion-electron mixtures
We combine techniques from quantum and from classical density functional
theory (DFT) to describe electron-ion mixtures. For homogeneous systems, we
show how to calculate ion-ion and ion-electron correlation functions within
Chihara's quantum hypernetted chain approximation, which we derive within a DFT
formulation. We also sketch out how to apply the DFT formulation to
inhomogeneous electron-ion mixtures, and use this to study the electron
distribution at the liquid-solid interface of Al.Comment: to be published in J. Non-Cryst. Solids, LAM 11 special issu
Instability and Degeneracy in the BMN Correspondence
Non-degenerate perturbation theory, which was used to calculate the scale
dimension of operators on the gauge theory side of the correspondence, breaks
down when effects of triple trace operators are included. We interpret this as
an instability of excited single-string states in the dual string theory for
decay into the continuum of degenerate 3-string states. We apply time-dependent
perturbation theory to calculate the decay widths from gauge theory. These
widths are new gauge theory data which can be compared with future calculations
in light cone string field theory.Comment: 23 pages, no figure
Refining human palaeodietary reconstruction using amino acid delta N-15 values of plants, animals and humans.
An established method of estimating the trophic level of an organism is through stable isotope analysis of
its tissues and those of its diet. This method has been used in archaeology to reconstruct past human diet
from the stable nitrogen isotope (d15N) values of human and herbivore bone collagen. However, this
approach, using the 15N-enrichment of human bone collagen d15N values over associated herbivore bone
collagen d15N values to predict the relative importance of animal protein, relies on the assumptions that:
(i) the d15N values of plants consumed by humans and herbivores are identical, and (ii) the 15Nenrichment
between diet and consumer is consistent. Bone collagen amino acid d15N values have the
potential to tackle these uncertainties, as they constrain the factors influencing bone collagen d15N
values. In this study, the d15N values of glutamic acid and phenylalanine in human and herbivore bone
collagen isolates from Neolithic sites in Germany, Greece and Turkey were determined by gas
chromatography-combustion-isotope ratio mass spectrometry. The fraction of animal protein in total
dietary protein consumed by the humans was estimated by: (i) comparing bulk human and herbivore
collagen d15N values, (ii) comparing bulk human and herbivore collagen and ancient charred cereal grain
d15N values, (iii) comparing human bone collagen d15NGlutamic acid and d15NPhenylalanine values, and (iv)
comparing d15NGlutamic acid values of human and herbivore bone collagen and estimated d15NGlutamic acid
values of ancient charred cereal grains. Where determined cereal grain d15N values are higher than
estimated herbivore forage values, estimates of animal protein consumption are significantly lower,
emphasising the importance of the plant nitrogen contribution to human bone collagen. This study also
highlights the need for further investigation into: (i) the D15NConsumer-Diet values of glutamic acid and
phenylalanine in terrestrial ecosystems, and (ii) D15NGlutamic acid-Phenylalanine values of common plant foods
in order to improve the accuracy and more widespread applicability of amino acid-based methods for
palaeodietary reconstruction
Non-perturbative effects in the BMN limit of N=4 supersymmetric Yang-Mills
One-instanton contributions to the correlation functions of two
gauge-invariant single-trace operators in N=4 SU(N) Yang-Mills theory are
studied in semi-classical approximation in the BMN limit. The most
straightforward examples involve operators with four bosonic impurities. The
explicit form for the correlation functions, which determine the anomalous
dimensions, follows after integration over the large number of bosonic and
fermionic moduli. Our results demonstrate that the instanton contributions
scale appropriately in the BMN limit. We find impressive agreement with the
D-instanton contributions to mass matrix elements of the dual plane-wave IIB
superstring theory, obtained in a previous paper. Not only does the dependence
on the scaled coupling constants match, but the dependence on the mode numbers
of the states is also in striking agreement.Comment: 52 pages, no figures, latex; V2: minor change
Stringing Spins and Spinning Strings
We apply recently developed integrable spin chain and dilatation operator
techniques in order to compute the planar one-loop anomalous dimensions for
certain operators containing a large number of scalar fields in N =4 Super
Yang-Mills. The first set of operators, belonging to the SO(6) representations
[J,L-2J,J], interpolate smoothly between the BMN case of two impurities (J=2)
and the extreme case where the number of impurities equals half the total
number of fields (J=L/2). The result for this particular [J,0,J] operator is
smaller than the anomalous dimension derived by Frolov and Tseytlin
[hep-th/0304255] for a semiclassical string configuration which is the dual of
a gauge invariant operator in the same representation. We then identify a
second set of operators which also belong to [J,L-2J,J] representations, but
which do not have a BMN limit. In this case the anomalous dimension of the
[J,0,J] operator does match the Frolov-Tseytlin prediction. We also show that
the fluctuation spectra for this [J,0,J] operator is consistent with the string
prediction.Comment: 27 pages, 4 figures, LaTex; v2 reference added, typos fixe
Two Mathematically Equivalent Versions of Maxwell's Equations
This paper is a review of the canonical proper-time approach to relativistic
mechanics and classical electrodynamics. The purpose is to provide a physically
complete classical background for a new approach to relativistic quantum
theory. Here, we first show that there are two versions of Maxwell's equations.
The new version fixes the clock of the field source for all inertial observers.
However now, the (natural definition of the effective) speed of light is no
longer an invariant for all observers, but depends on the motion of the source.
This approach allows us to account for radiation reaction without the
Lorentz-Dirac equation, self-energy (divergence), advanced potentials or any
assumptions about the structure of the source. The theory provides a new
invariance group which, in general, is a nonlinear and nonlocal representation
of the Lorentz group. This approach also provides a natural (and unique)
definition of simultaneity for all observers. The corresponding particle theory
is independent of particle number, noninvariant under time reversal (arrow of
time), compatible with quantum mechanics and has a corresponding positive
definite canonical Hamiltonian associated with the clock of the source.
We also provide a brief review of our work on the foundational aspects of the
corresponding relativistic quantum theory. Here, we show that the standard
square-root and the Dirac equations are actually two distinct
spin- particle equations.Comment: Appeared: Foundations of Physic
Density-functional embedding using a plane-wave basis
The constrained electron density method of embedding a Kohn-Sham system in a
substrate system (first described by P. Cortona, Phys. Rev. B {\bf 44}, 8454
(1991) and T.A. Wesolowski and A. Warshel, J. Phys. Chem {\bf 97}, 8050 (1993))
is applied with a plane-wave basis and both local and non-local
pseudopotentials. This method divides the electron density of the system into
substrate and embedded electron densities, the sum of which is the electron
density of the system of interest. Coupling between the substrate and embedded
systems is achieved via approximate kinetic energy functionals. Bulk aluminium
is examined as a test case for which there is a strong interaction between the
substrate and embedded systems. A number of approximations to the
kinetic-energy functional, both semi-local and non-local, are investigated. It
is found that Kohn-Sham results can be well reproduced using a non-local
kinetic energy functional, with the total energy accurate to better than 0.1 eV
per atom and good agreement between the electron densities.Comment: 11 pages, 4 figure
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