Static, massive fields and vacuum polarization potential in Rindler space

In Rindler space, we determine in terms of special functions the expression of the static, massive scalar or vector field generated by a point source. We find also an explicit integral expression of the induced electrostatic potential resulting from the vacuum polarization due to an electric charge at rest in the Rindler coordinates. For a weak acceleration, we give then an approximate expression in the Fermi coordinates associated with the uniformly accelerated observer.Comment: 11 pages, latex, no figure

Exploring the COT Briefing Paper on Sustainable Development: reducing carbon without reducing health

The development of efficient and effective service delivery in health and social care, to meet the needs of service users in this changing world. WFOT 2012 has called for occupational therapy practice to incorporate sustainable development.Occupational therapists could re-evaluate practice models and expand clinical reasoning about occupational performance to include global issues.In the UK, Climate Change will bring new challenges to the way occupational therapists work. If action is taken now some of the worst effects of climate change could be mitigated or prevented. There could be also needs to be preparation and planning for the inevitable challenges to come.The occupational therapy profession has an important role to play in sustainable health and social care at all levels and across all domains

Professional judgement and decision-making in social work

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Social Work Practice on 3/04/2018, available online: http://www.tandfonline.com/10.1080/02650533.2018.1462780 Editorial for a special issue on Professional Judgement and Decision Making in Social Wor

Ash grains of the 1991 Mt. Pinatubo eruption as a tracer in Rose Bengal stained deep sea agglutinated foraminifera: How old is Freddy?

The use of volcanic ash particles (including dark-coloured grains) by agglutinated foraminifera that survived the 1991 eruption of Mt Pinatubo volcano provides a useful tracer to help determine growth rates and longevity in the deep sea. In the case of a specimen of Cyclammina pusilla Brady, the rate of chamber addition in this Rose Bengal stained sub-adult individual is three chambers over a timespan of five and one-half years

Estimating the weak-lensing rotation signal in radio cosmic shear surveys

Weak lensing has become an increasingly important tool in cosmology and the use of galaxy shapes to measure cosmic shear has become routine. The weak-lensing distortion tensor contains two other effects in addition to the two components of shear: the convergence and rotation. The rotation mode is not measurable using the standard cosmic shear estimators based on galaxy shapes, as there is no information on the original shapes of the images before they were lensed. Due to this, no estimator has been proposed for the rotation mode in cosmological weak-lensing surveys, and the rotation mode has never been constrained. Here, we derive an estimator for this quantity, which is based on the use of radio polarisation measurements of the intrinsic position angles of galaxies. The rotation mode can be sourced by physics beyond $\Lambda$CDM, and also offers the chance to perform consistency checks of $\Lambda$CDM and of weak-lensing surveys themselves. We present simulations of this estimator and show that, for the pedagogical example of cosmic string spectra, this estimator could detect a signal that is consistent with the constraints from Planck. We examine the connection between the rotation mode and the shear $B$-modes and thus how this estimator could help control systematics in future radio weak-lensing surveys

Comparative evaluation of GHG emissions from the use of Miscanthus for bio-hydrocarbon production via fast pyrolysis and bio-oil upgrading

This study examines the GHG emissions associated with producing bio-hydrocarbons via fast pyrolysis of Miscanthus. The feedstock is then upgraded to bio-oil products via hydroprocessing and zeolite cracking. Inventory data for this study were obtained from current commercial cultivation practices of Miscanthus in the UK and state-of-the-art process models developed in Aspen Plus®. The system boundary considered spans from the cultivation of Miscanthus to conversion of the pyrolysis-derived bio-oil into bio-hydrocarbons up to the refinery gate. The Miscanthus cultivation subsystem considers three scenarios for soil organic carbon (SOC) sequestration rates. These were assumed as follows: (i) excluding (SOC), (ii) low SOC and (iii) high (SOC) for best and worst cases. Overall, Miscanthus cultivation contributed moderate to negative values to GHG emissions, from analysis of excluding SOC to high SOC scenarios. Furthermore, the rate of SOC in the Miscanthus cultivation subsystem has significant effects on total GHG emissions. Where SOC is excluded, the fast pyrolysis subsystem shows the highest positive contribution to GHG emissions, while the credit for exported electricity was the main ‘negative’ GHG emission contributor for both upgrading pathways. Comparison between the bio-hydrocarbons produced from the two upgrading routes and fossil fuels indicates GHG emission savings between 68% and 87%. Sensitivity analysis reveals that bio-hydrocarbon yield and nitrogen gas feed to the fast pyrolysis reactor are the main parameters that influence the total GHG emissions for both pathways

Studies on the auchenorrhyncha (hemoptera – insecta) of Pennine moorland with special reference to the ceropidae

Notes on the autecology of 32 species of Auchenorrhyncha from the Moore House National Nature Reserve are given. Studies were made of the microclimates of the common vegetation types on which these occur and it is shown that the size and function as a temperature regulator of the spittle (produced by nymphs of the cercopidae) is associated with these gradients. Cercopid nymohs are shown to change feeding sites after moulting. The need to change host plants and thus leave protective spittle is thought to result in an increased mortality of nymphs (up to 3 per cent per day). Overall nymphal mortality is not dependent on population density. In two cercopids (Neophilaenus lineatus and Neophilaenus exclamationis), there are marked changes in population density in each year (1961 to 1963) and these are partly attributed to climatic factors. The hatch of cercopidae is delayed, and development is retarded at high altitides. Nymphal mortality rates in a cicadellid (macrosteles sexnotatus) and a delphacid (conomelus anceps) did not differ from those of the ceropidae studied, although they have no protective spittle. It is concluded that cercopid spittke is of some survival value at moore House by enabling the nymph to avoid parasites, if not predators, and unfavourable climatic conditions encountered whilst remaining stationary on the host plant during feeding. These advantages are not sufficient to give the Cercopidae a significantly higher survival rate than other Auchenorrhyncha at Moor House. Non-density dependent factors are thought to be responsible for a major part of the changes in population density. A compensatory mechanism at other stages of the life cycle has not been demonstrated. Local extinction at the edge of the range is a result of climatic factors. The population studied is probably below the density level at which regulating mechanisms may occur

Saddle Points and Stark Ladders: Exact Calculations of Exciton Spectra in Superlattices

A new, exact method for calculating excitonic absorption in superlattices is described. It is used to obtain high resolution spectra showing the saddle point exciton feature near the top of the miniband. The evolution of this feature is followed through a series of structures with increasing miniband width. The Stark ladder of peaks produced by an axial electric field is investigated, and it is shown that for weak fields the line shapes are strongly modified by coupling to continuum states, taking the form of Fano resonances. The calculated spectra, when suitably broadened, are found to be in good agreement with experimental results.Comment: 9 pages Revtex v3.0, followed by 4 uuencoded postscript figures, SISSA-CM-94-00

An Invertible Linearization Map for the Quartic Oscillator

The set of world lines for the non-relativistic quartic oscillator satisfying Newton's equation of motion for all space and time in 1-1 dimensions with no constraints other than the "spring" restoring force is shown to be equivalent (1-1-onto) to the corresponding set for the harmonic oscillator. This is established via an energy preserving invertible linearization map which consists of an explicit nonlinear algebraic deformation of coordinates and a nonlinear deformation of time coordinates involving a quadrature. In the context stated, the map also explicitly solves Newton's equation for the quartic oscillator for arbitrary initial data on the real line. This map is extended to all attractive potentials given by even powers of the space coordinate. It thus provides classes of new solutions to the initial value problem for all these potentials

Coherence properties of the microcavity polariton condensate

A theoretical model is presented which explains the dominant decoherence process in a microcavity polariton condensate. The mechanism which is invoked is the effect of self-phase modulation, whereby interactions transform polariton number fluctuations into random energy variations. The model shows that the phase coherence decay, g1(t), has a Kubo form, which can be Gaussian or exponential, depending on whether the number fluctuations are slow or fast. This fluctuation rate also determines the decay time of the intensity correlation function, g2(t), so it can be directly determined experimentally. The model explains recent experimental measurements of a relatively fast Gaussian decay for g1(t), but also predicts a regime, further above threshold, where the decay is much slower.Comment: 5 pages, 1 figur