Evaluating the effectiveness and cost-effectiveness of Dementia Care Mapping™ to enable person-centred care for people with dementia and their carers (DCM-EPIC) in care homes: study protocol for a randomised controlled trial

Background Up to 90 % of people living with dementia in care homes experience one or more behaviours that staff may describe as challenging to support (BSC). Of these agitation is the most common and difficult to manage. The presence of agitation is associated with fewer visits from relatives, poorer quality of life and social isolation. It is recommended that agitation is treated through psychosocial interventions. Dementia Care Mapping™ (DCM™) is an established, widely used observational tool and practice development cycle, for ensuring a systematic approach to providing person-centred care. There is a body of practice-based literature and experience to suggests that DCM™ is potentially effective but limited robust evidence for its effectiveness, and no examination of its cost-effectiveness, as a UK health care intervention. Therefore, a definitive randomised controlled trial (RCT) of DCM™ in the UK is urgently needed. Methods/design A pragmatic, multi-centre, cluster-randomised controlled trial of Dementia Care Mapping (DCM™) plus Usual Care (UC) versus UC alone, where UC is the normal care delivered within the care home following a minimum level of dementia awareness training. The trial will take place in residential, nursing and dementia-specialist care homes across West Yorkshire, Oxfordshire and London, with residents with dementia. A random sample of 50 care homes will be selected within which a minimum of 750 residents will be registered. Care homes will be randomised in an allocation ratio of 3:2 to receive either intervention or control. Outcome measures will be obtained at 6 and 16 months following randomisation. The primary outcome is agitation as measured by the Cohen-Mansfield Agitation Inventory, at 16 months post randomisation. Key secondary outcomes are other BSC and quality of life. There will be an integral cost-effectiveness analysis and a process evaluation. Discussion The protocol was refined following a pilot of trial procedures. Changes include replacement of a questionnaire, whose wording caused some residents distress, to an adapted version specifically designed for use in care homes, a change to the randomisation stratification factors, adaption in how the staff measures are collected to encourage greater compliance, and additional reminders to intervention homes of when mapping cycles are due, via text message. Trial registration Current Controlled Trials ISRCTN82288852. Registered on 16 January 2014. Full protocol version and date: v7.1: 18 December 2015

British Romanticism and the Global Climate

As a result of developments in the meteorological and geological sciences, the Romantic period saw the gradual emergence of attempts to understand the climate as a dynamic global system that could potentially be affected by human activity. This chapter examines textual responses to climate disruption cause by the Laki eruption of 1783 and the Tambora eruption of 1815. During the Laki haze, writers such as Horace Walpole, Gilbert White, and William Cowper found in Milton a powerful way of understanding the entanglements of culture and climate at a time of national and global crisis. Apocalyptic discourse continued to resonate during the Tambora crisis, as is evident in eyewitness accounts of the eruption, in the utopian predictions of John Barrow and Eleanor Anne Porden, and in the grim speculations of Byron’s ‘Darkness’. Romantic writing offers a powerful analogue for thinking about climate change in the Anthropocene

A Fourier Series Based Atmospheric Phase Screen Generator for Simulating Nonisoplanatic Geometries and Temporal Evolution

. A new Fourier Series atmospheric phase screen generator is introduced. A Fourier Series (FS) is used to represent the wavefront phase as a two dimensional periodic function. The period of the function is chosen to be much larger than the outer scale of the turbulence and thus the FS accurately represents the power in the low spatial frequencies of the wavefront. The accuracy of the representation of the high spatial frequencies is determined by the number of terms used in the FS expansion. The FS based screen generator is capable of simulating atmospheric-induced wavefront phase distortions arising from temporal and/or anisoplanatic conditions. Both the spatial and temporal correlations between wavefront phases screens separated by time and/or angle are properly modeled. The conventional approach of simulating temporal evolution by making a large phase screen and then shifting is avoided. The phase screen generator is presented in an extremely compact and simple vector notation that ..

Speckle Imaging Signal-to-Noise Performance as a Function of Frame Integration Time

In the past 10 years astronomical image reconstruction based on a variety of speckle techniques have become popular means of enhancing and improving the resolution of turbulence degraded images. These techniques are based on the Fourier processing of a large number of turbulence degraded "snapshots" or frames of the irradiance in the system's image plane. The number of snapshots needed is largely a function of the signal-to-noise ratio (SNR) of the Fourier components of a single snapshot. Estimating these Fourier components is hampered by the inherent noise induced by the photon detection process and the random effect of the turbulent atmosphere. In most cases the SNR is much less than unity and many frames are averaged to improve the overall SNR. It is well established that if the frames are uncorrelated then the SNR improves over the single frame SNR by a factor of p m where m is the number of frames averaged. This fact implies that the smallest exposure time possible is desirable ..

Design and performance analysis of adaptive optical telescopes using laser guide stars

Atmospheric turbulence severely limits the resolution of ground-based astronomical telescopes. In good seeing conditions at the best observatory sites, resolution at visible wavelengths is typically limited to $\sim$1 sec of arc. During the past 15 years adaptive optical systems using electrically deformable mirrors have been developed to compensate for turbulence effects. Unfortunately, these systems require bright reference sources adjacent to the object of interest and can be used to observe only the brightest stars. Artificial guide stars suitable for controlling an adaptive imaging system can be created in the upper atmosphere by using a laser to excite either Rayleigh backscattering in the stratosphere or resonance backscattering in the mesospheric Na layer. The design requirements of a laser-guided adaptive telescope, as well as the expected imaging performance, are discussed in detail in this thesis.Analytical expressions giving the performance of a class of adaptive optics systems using slope sensors are derived. The unique analysis takes into account the nonideal characteristics of the wavefront sensor and wavefront correction device, as well as the effects of anisoplanatism. Performance measures include the mean-square residual phase error across the aperture of the optical system and the optical transfer function. We show that a two-meter, ground-based, laser-guided telescope can achieve imaging performance levels at visible wavelengths nearly matching those of the Hubble Space Telescope (HST). The laser power requirement for Rayleigh and Na guide stars is on the order of 33 W and 6 W, respectively, for zenith viewing and r\sp{\rm o} = 20 cm. Both systems will achieve near diffraction limited imaging with a Strehl ratio of $\sim$ 0.73 and an angular resolution of approximately 0.07 arcsec for an observation wavelength of 0.5 $\mu$m.In the case of guide stars created in the mesospheric Na layer, saturation effects may significantly reduce the backscattered signal expected for resonance fluorescence lidar systems. The level of saturation is determined by the laser's pulse length, pulse energy, beamwidth and linewidth. Design examples, including lidar systems for atmospheric research and laser-guided telescopes, are studied in detail.U of I OnlyETDs are only available to UIUC Users without author permissio

Signal-to-Noise Comparison of Deconvolution From Wave Front Sensing With Traditional Linear and Speckle Image Reconstruction

It is well known that atmospheric turbulence severely degrades the performance of ground based imaging systems. Techniques to overcome the effects of the atmosphere have been developing at a rapid pace over the last 10 years. These techniques can be grouped into two broad categories: pre-detection and post detection techniques. A recent newcomer to the post detection scene is "deconvolution from wave front sensing" (DWFS). DWFS is a post-detection image reconstruction technique that makes use of one feature of pre-detection techniques. A WFS is used to record the wave front phase distortion in the pupil of the telescope for each short exposure image. The additional information provided by the WFS is used to estimate of the system's point spread function (PSF). The PSF is then used in conjunction with the ensemble of short exposure images to obtain an estimate of the object intensity distribution via deconvolution. With the addition of DWFS into the suite of possible post detection imag..

Tilt estimation in moderate-to-strong scintillation

Adaptive optics systems are being applied in ever more challenging environments, for example, the projection of lasers over long horizontal paths through the atmosphere. These long atmospheric paths corrupt the signal received from the beacon and typically yield highly scintillated received wave fronts. Tilt estimation for controlling the fast steering mirror in these systems is complicated by the presence of branch points in the scintillated received wave fronts. In particular, correlation between the tilt and the projected beam’s centroid error at the target has been observed in horizontal laser beam projection experiments. The presence of this correlation indicates that better tracking performance should be achievable. We compare the performance of four estimation schemes applied to tilt estimation in a horizontal laser projection system. It is demonstrated that all four schemes underestimate the tilt required to return the laser beam to a target in highly scintillated environments. A method of correcting this tilt is presented, and the expected performance improvement is quantified. © 2001 Optical Society of America

Performance analysis of a Hartmann wavefront sensor used for sensing atmospheric turbulence statistics

The ability to measure atmospheric turbulence characteristics such as Fried\u27s coherence diameter, the outer scale of turbulence, and the turbulence power law are critical for the optimized operation of adaptive optical telescopes. One approach for sensing these turbulence parameters is to use a Hartmann wavefront sensor (H-WFS) array to measure the wavefront slope structure function (SSF). The SSF is defined as the second moment of the wavefront slope difference between any two subapertures separated in time and/or space. Accurate knowledge of the SSF allows turbulence parameters to be estimated. The H-WFS slope measurements, composed of a true slope signal corrupted by noise, are used to estimate the SSF by computing a mean square difference of slope signals from different subapertures. This computation is typically performed over a large number of H-WFS measurement frames. The quality of the SSF estimate is quantified by the signal-to-noise ratio (SNR) of the estimator. The quality of the SSF estimate then can in turn be related to the quality of the atmospheric turbulence parameter estimates. This research develops a theoretical SNR expression for the SSF estimator. This SNR is a function of H-WFS geometry, the number of temporal measurement frames, the outer scale of turbulence, the turbulence spectrum power law, and the temporal properties of the turbulence. Results are presented for various H-WFS configurations and atmospheric turbulence properties. ©2005 Copyright SPIE - The International Society for Optical Engineering

Limitations of Gaussian assumptions for the irradiance distribution in digital imagery: Nonstationary image ensemble considerations

Gaussian assumptions for the irradiance probability density in a digital image are often employed but rarely justified. We provide a mathematical justification for these assumptions and indicate the limitations of their use. Beginning with the context-dependent image ensemble considerations introduced by Hunt and Cannon [IEEE Trans. Syst. Man Cybern. SMC-6, 876 (1976)], such an ensemble is found to be accurately modeled as a Gaussian random process with nonstationary mean and nonstationary variance. An ensemble transformation is deduced and confirmed empirically that yields a Gaussian, zero-mean, unit-variance, ergodic random process. This conclusion leads to an image model that predicts that the distribution of image irradiance values after local mean removal is determined only by the distribution of local standard deviation values in the image. An analytic expression is derived for the probability density function of these irradiance values and is validated experimentally. This expression indicates that the distribution of image irradiance values after local mean removal may be assumed to be Gaussian only when the local standard deviation in an image is a nearly stationary quantity. © 1998 Optical Society of America