Acting is the key: new directions for the stimulation of prospective memory in mild cognitive impairment

Background: The fulfillment of delayed intended actions (e.g. taking medication or attending an appointment) is described in the literature as prospective memory (PM), and is often pointed out as a fairly common concern for healthy adults in everyday life constituting a fundamental requirement for independent living across the lifespan. PM may be compromised in the course of healthy aging and may be particularly disrupted very early in the neurodegenerative process, namely at the stage of Mild Cognitive Impairment (MCI), which usually represents an initial phase of Alzheimer’s disease (AD), severely affecting a self-sufficient life-style and causing immense apprehension to caregivers. Methods: We have addressed this issue by investigating whether enactment at encoding could improve PM performance and whether these potential benefits were dependent of the relationship between the retrieval cue and its associated action. We report findings that explored this hypothesis in 64 young adults aged 18-39 years (M ¼ 20.41, SD ¼ 3.553) and 64 educationally matched older adults aged 58-90 years (M ¼ 71.17, SD ¼ 7.204) using a behavioral PM testing paradigm with a 2 X 2 X 2 between-subject factorial design. Results: Older adults’ PM performance (like that of their younger counterparts) benefited from enactment at encoding and from a strong semantic cue-action relation. Furthermore, there were no reliable effects of encoding modality or cue-action relatedness on performance accuracy or speed, despite a generalized slowness associated with age. Importantly, these beneficial effects were maintained across the lifespan, and even under high attentional demands. Figure 1. Mean proportion of PM cues eliciting a correct response at the appropriate moment in each Method of Encoding X Cue-Action Relatedness X Ag

Heterotic - type I superstring duality and low-energy effective actions

We compare order $R^4$ terms in the 10-dimensional effective actions of SO(32) heterotic and type I superstrings from the point of view of duality between the two theories. Some of these terms do not receive higher-loop corrections being related by supersymmetry to `anomaly-cancelling' terms which depend on the antisymmetric 2-tensor. At the same time, the consistency of duality relation implies that the `tree-level' $R^4$ super-invariant (the one which has $\zeta(3)$-coefficient in the sphere part of the action) should appear also at higher orders of loop expansion, i.e. should be multiplied by a non-trivial function of the dilaton.Comment: 16 pages, harvma

Neural correlates of true and false memory in mild cognitive impairment

The goal of this research was to investigate the changes in neural processing in mild cognitive impairment. We measured phase synchrony, amplitudes, and event-related potentials in veridical and false memory to determine whether these differed in participants with mild cognitive impairment compared with typical, age-matched controls. Empirical mode decomposition phase locking analysis was used to assess synchrony, which is the first time this analysis technique has been applied in a complex cognitive task such as memory processing. The technique allowed assessment of changes in frontal and parietal cortex connectivity over time during a memory task, without a priori selection of frequency ranges, which has been shown previously to influence synchrony detection. Phase synchrony differed significantly in its timing and degree between participant groups in the theta and alpha frequency ranges. Timing differences suggested greater dependence on gist memory in the presence of mild cognitive impairment. The group with mild cognitive impairment had significantly more frontal theta phase locking than the controls in the absence of a significant behavioural difference in the task, providing new evidence for compensatory processing in the former group. Both groups showed greater frontal phase locking during false than true memory, suggesting increased searching when no actual memory trace was found. Significant inter-group differences in frontal alpha phase locking provided support for a role for lower and upper alpha oscillations in memory processing. Finally, fronto-parietal interaction was significantly reduced in the group with mild cognitive impairment, supporting the notion that mild cognitive impairment could represent an early stage in Alzheimer’s disease, which has been described as a ‘disconnection syndrome’

The Search for the Dark Matter: WIMPs and MACHOs

Review talk presented at the Texas/PASCOS Symposium, Berkeley, CA, Dec 1992. We review the status of experiments and ideas relevant for the detection of the dark matter which is suspected to be the dominant constituent of the Universe. Great progress is being made and the chances are non-negligible that one of the many currently in-progress experiments will discover the nature of the dark matter. We discuss the main dark matter candidates, and review the experiments relevant to each of them.Comment: 17 pages, tex, figures not include

GNOSIS: the first instrument to use fibre Bragg gratings for OH suppression

GNOSIS is a prototype astrophotonic instrument that utilizes OH suppression fibres consisting of fibre Bragg gratings and photonic lanterns to suppress the 103 brightest atmospheric emission doublets between 1.47-1.7 microns. GNOSIS was commissioned at the 3.9-meter Anglo-Australian Telescope with the IRIS2 spectrograph to demonstrate the potential of OH suppression fibres, but may be potentially used with any telescope and spectrograph combination. Unlike previous atmospheric suppression techniques GNOSIS suppresses the lines before dispersion and in a manner that depends purely on wavelength. We present the instrument design and report the results of laboratory and on-sky tests from commissioning. While these tests demonstrated high throughput and excellent suppression of the skylines by the OH suppression fibres, surprisingly GNOSIS produced no significant reduction in the interline background and the sensitivity of GNOSIS and IRIS2 is about the same as IRIS2. It is unclear whether the lack of reduction in the interline background is due to physical sources or systematic errors as the observations are detector noise-dominated. OH suppression fibres could potentially impact ground-based astronomy at the level of adaptive optics or greater. However, until a clear reduction in the interline background and the corresponding increasing in sensitivity is demonstrated optimized OH suppression fibres paired with a fibre-fed spectrograph will at least provide a real benefits at low resolving powers.Comment: 15 pages, 13 figures, accepted to A

Revealing components of the galaxy population through nonparametric techniques

The distributions of galaxy properties vary with environment, and are often multimodal, suggesting that the galaxy population may be a combination of multiple components. The behaviour of these components versus environment holds details about the processes of galaxy development. To release this information we apply a novel, nonparametric statistical technique, identifying four components present in the distribution of galaxy H$\alpha$ emission-line equivalent-widths. We interpret these components as passive, star-forming, and two varieties of active galactic nuclei. Independent of this interpretation, the properties of each component are remarkably constant as a function of environment. Only their relative proportions display substantial variation. The galaxy population thus appears to comprise distinct components which are individually independent of environment, with galaxies rapidly transitioning between components as they move into denser environments.Comment: 12 pages, 10 figures, accepted for publication in MNRA

Evolution of Galactic Discs: Multiple Patterns, Radial Migration and Disc Outskirts

We investigate the evolution of galactic disks in N-body Tree-SPH simulations. We find that disks, initially truncated at three scale-lengths, can triple their radial extent, solely driven by secular evolution. Both Type I (single exponential) and Type II (down-turning) observed disk surface-brightness profiles can be explained by our findings. We relate these results to the strong angular momentum outward transfer, resulting from torques and radial migration associated with multiple patterns, such as central bars and spiral waves of different multiplicity. We show that even for stars ending up on cold orbits, the changes in angular momentum exhibit complex structure as a function of radius, unlike the expected effect of transient spirals alone. Focussing on one of our models, we find evidence for non-linear coupling among m=1, 2, 3 and 4 density waves, where m is the pattern multiplicity. We suggest that the naturally occurring larger resonance widths at galactic radii beyond four scale-lengths may have profound consequences on the formation and location of breaks in disk density profiles, provided spirals are present at such large distances. We also consider the effect of gas inflow and show that when in-plane smooth gas accretion of ~5 M_sun/yr is included, the outer disks become more unstable, leading to a strong increase in the stellar velocity dispersion. This, in turn, causes the formation of a Type III (up-turning) profile in the old stellar population. We propose that observations of Type III surface brightness profiles, combined with an up-turn in the stellar velocity dispersions beyond the disk break, could be a signature of ongoing gas-accretion. The results of this study suggest that disk outskirts comprised of stars migrated from the inner disk would have relatively large radial velocity dispersions, and significant thickness when seen edge-on. [Abridged]Comment: Replaced with accepted version. New Fig. 5 added, Section 10 decreased in size, old Fig. 17 removed. Conclusions remain the same. High-resolution version can be found at http://www.ivanminchev.co

Foreign language educators’ exposure to research: reported experiences, exposure via citations, and a proposal for action

This article reports on 2 connected studies that provide data about the flow of research to foreign language (FL) educators in majority Anglophone contexts. The first study investigated exposure to research among FL educators in the United Kingdom using 2 surveys (n = 391; n = 183). The data showed (a) some limited exposure to research via professional association publications and events, (b) negligible direct exposure to publications in the Social Science Citation Index (SSCI), (c) barriers to exposure caused by poor physical and conceptual access, despite generally positive perceptions of research, and (d) the importance of university‐based teacher educators for research–practice interfaces. The second study investigated the potential for indirect exposure to research from 7 professional publications over 5 years in Australia, the United Kingdom, and the United States. We systematically reviewed the extent to which these professional publications referenced 29 SSCI journals that aim to publish pedagogy‐relevant research. In our corpus of 8,516 references in 284 articles in professional journals, the mean proportion of references to all 29 SSCI journals, combined, was 12.43% per professional article. The overall mean number of references to each SSCI journal was 0.17 per professional article. The emerging picture is rather bleak, and we propose action from academic journals and researchers to promote a more international, systematic, and sustainable flow of research

Transitions at the end of life for older adults - patient, carer and professional perspectives

BackgroundThe end of life may be a time of high service utilisation for older adults. Transitions between care settings occur frequently, but may produce little improvement in symptom control or quality of life for patients. Ensuring that patients experience co-ordinated care, and moves occur because of individual needs rather than system imperatives, is crucial to patients’ well-being and to containing health-care costs.ObjectiveThe aim of this study was to understand the experiences, influences and consequences of transitions between settings for older adults at the end of life. Three conditions were the focus of study, chosen to represent differing disease trajectories.SettingEngland.ParticipantsThirty patients aged over 75 years, in their last year of life, diagnosed with heart failure, lung cancer and stroke; 118 caregivers of decedents aged 66–98 years, who had died with heart failure, lung cancer, stroke, chronic obstructive pulmonary disease or selected other cancers; and 43 providers and commissioners of services in primary care, hospital, hospice, social care and ambulance services.Design and methodsThis was a mixed-methods study, composed of four parts: (1) in-depth interviews with older adults; (2) qualitative interviews and structured questionnaire with bereaved carers of older adult decedents; (3) telephone interviews with care commissioners and providers using case scenarios derived from the interviews with carers; and (4) analysis of linked Hospital Episode Statistics (HES) and mortality data relating to hospital admissions for heart failure and lung cancer in England 2001–10.ResultsTransitions between care settings in the last year of life were a common component of end-of-life care across all the data sets that made up this study, and many moves were made shortly before death. Patients’ and carers’ experiences of transitions were of a disjointed system in which organisational processes were prioritised over individual needs. In many cases, the family carer was the co-ordinator and provider of care at home, excluded from participation in institutional care but lacking the information and support to extend their role with confidence. The general practitioner (GP) was a valued, central figure in end-of-life care across settings, though other disciplines were critical of GPs’ expertise and adherence to guidelines. Out-of-hours services and care homes were identified by many as contributors to unnecessary transitions. Good relationships and communication between professionals in different settings and sectors was recognised by families as one of the most important influences on transitions but this was rarely acknowledged by staff.ConclusionsDevelopment of a shared understanding of professional and carer roles in end-of-life transitions may be one of the most effective ways of improving patients’ experiences. Patients and carers manage many aspects of end-of-life care for themselves. Identifying ways to extend their skills and strengthen their voices, particularly in hospital settings, would be welcomed and may reduce unnecessary end-of-life transitions. Why the experiences of carers appear to have changed little, despite the implementation of a range of relevant policies, is an important question that has not been answered. Recommendations for future research include the relationship between policy interventions and the experiences of end-of-life carers; identification of ways to harmonise understanding of the carers’ role and strengthen their voice, particularly in hospital settings; identification of ways to reduce the influence of interprofessional tensions in end-of-life care; and development of interventions to enhance patients’ experiences across transitions.FundingThe National Institute for Health Research Health Services and Delivery Research programme