Detection of radiation pressure acting on 2009 BD

We report the direct detection of radiation pressure on the asteroid 2009 BD, one of the smallest multi-opposition near-Earth objects currently known, with H ~ 28.4. Under the purely gravitational model of NEODyS the object is currently considered a possible future impactor, with impact solutions starting in 2071. The detection of a radiation-related acceleration allows us to estimate an Area to Mass Ratio (AMR) for the object, that can be converted (under some assumptions) into a range of possible values for its average density. Our result AMR = (2.97 \pm 0.33) x 10^(-4) m^2 kg^(-1) is compatible with the object being of natural origin, and it is narrow enough to exclude a man-made nature. The possible origin of this object, its future observability, and the importance of radiation pressure in the impact monitoring process, are also discussed.Comment: To be submitted for refereed publication. Preliminary analysis based on the 2009-2010 data, published on arXiv because of the current observability window of the targe

Consequences of a Distant Massive Planet on the Large Semi-major Axis Trans-Neptunian Objects

We explore the distant giant planet hypothesis by integrating the large semi-major axis, large pericenter Trans-Neptunian Objects (TNOs) in the presence of the giant planets and an external perturber whose orbit is consistent with the proposed distant, eccentric, and inclined giant planet, so called planet 9. We find that TNOs with semi-major axes greater than 250 au experience some longitude of perihelion shepherding, but that a generic outcome of such evolutions is that the TNOs evolve to larger pericenter orbits, and commonly get raised to retrograde inclinations. This pericenter and inclination evolution requires a massive disk of TNOs (tens of M_\Earth) in order to explain the detection of the known sample today. Some of the highly inclined orbits produced by the examined perturbers will be inside of the orbital parameter space probed by prior surveys, implying a missing signature of the 9th planet scenario. The distant giant planet scenarios explored in this work do not reproduce the observed signal of simultaneous clustering in argument of pericenter, longitude of the ascending node, and longitude of perihelion in the region of the known TNOs

The treatment of hypertension in people with dementia: a multi-centre prospective observational cohort study

ObjectivesTo describe the treatment of hypertension in people with dementia and collate evidence on adverse health events whilst on treatment.DesignA multicenter prospective observational cohort study.Setting and participantsPeople with documented diagnoses of hypertension and dementia were recruited through memory clinics and general practice from 8 sites in the United Kingdom.MethodsThe cohort was recruited between July 2013 and October 2014. Participants underwent face-to-face, standardized assessment of blood pressure (BP), activities of daily living, cognitive function, and medication use. Follow-up was by monthly telephone interview for 6 months to collate data on adverse health events.Results181 participants were recruited and 177 followed up; 126 (70%) were female, mean age was 82 [standard deviation (SD) 6.3] years, median Mini-Mental State Examination score was 23 [interquartile range (IQR) 18-26] and mean BP was 141/78 (SD 22/12) mmHg. Antihypertensive drugs were prescribed in 157 (87%). Participants were prescribed a median of 1 (IQR 1-2) antihypertensive medication. Angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers were the most frequently prescribed antihypertensives in 63% of participants. Target BP was achieved in 58% (95% confidence interval 49%-64%). Increasing number of antihypertensives was not associated with lower systolic or diastolic BP, or with a higher proportion of patients attaining target BP. Participants had 214 falls, 3 had a fracture, 3 developed symptomatic heart failure, 4 had cerebrovascular events, and 8 died.Conclusions/ImplicationsIn this population of people with mild dementia, participants were treated with standard antihypertensive medications in a similar proportion to the general population, with a similar proportion achieving target BP. The rate of adverse health events was higher than in randomized controlled trials of antihypertensives and raises reservations about the assumptions underpinning antihypertensive treatment in people with dementia. These findings may help inform clinical decision making

Are we teaching our students what they need to know about ageing? Results from the National Survey of Undergraduate Teaching in Ageing and Geriatric Medicine

Introduction - Learning about ageing and the appropriate management of older patients is important for all doctors. This survey set out to evaluate what medical undergraduates in the UK are taught about ageing and geriatric medicine and how this teaching is delivered. Methods – An electronic questionnaire was developed and sent to the 28/31 UK medical schools which agreed to participate. Results – Full responses were received from 17 schools. 8/21 learning objectives were recorded as taught, and none were examined, across every school surveyed. Elder abuse and terminology and classification of health were taught in only 8/17 and 2/17 schools respectively. Pressure ulcers were taught about in 14/17 schools but taught formally in only 7 of these and examined in only 9. With regard to bio- and socio- gerontology, only 9/17 schools reported teaching in social ageing, 7/17 in cellular ageing and 9/17 in the physiology of ageing. Discussion – Even allowing for the suboptimal response rate, this study presents significant cause for concern with UK undergraduate education related to ageing. The failure to teach comprehensively on elder abuse and pressure sores, in particular, may be significantly to the detriment of older patients

The Kuiper Belt Luminosity Function from m(R)=21 to 26

We have performed an ecliptic imaging survey of the Kuiper belt with our deepest and widest field achieving a limiting flux of m(g') = 26.4, with a sky coverage of 3.0 square-degrees. This is the largest coverage of any other Kuiper belt survey to this depth. We detect 72 objects, two of which have been previously observed. We have improved the Bayesian maximum likelihood fitting technique presented in Gladman et al. (1998) to account for calibration and sky density variations and have used this to determine the luminosity function of the Kuiper belt. Combining our detections with previous surveys, we find the luminosity function is well represented by a single power-law with slope alpha = 0.65 +/- 0.05 and an on ecliptic sky density of 1 object per square-degree brighter than m(R)=23.42 +/- 0.13. Assuming constant albedos, this slope suggests a differential size-distribution slope of 4.25 +/- 0.25, which is steeper than the Dohnanyi slope of 3.5 expected if the belt is in a state of collisional equilibrium. We find no evidence for a roll-over or knee in the luminosity function and reject such models brightward of m(R) ~ 24.6.Comment: 50 Pages, 8 Figure

Effective health care for older people resident in care homes: the optimal study protocol for realist review

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Care homes in the UK rely on general practice for access to specialist medical and nursing care as well as referral to therapists and secondary care. Service delivery to care homes is highly variable in both quantity and quality. This variability is also evident in the commissioning and organisation of care home-specific services that range from the payment of incentives to general practitioners (GPs) to visit care homes, to the creation of care home specialist teams and outreach services run by geriatricians. No primary studies or systematic reviews have robustly evaluated the impact of these different approaches on organisation and resident-level outcomes. Our aim is to identify factors which may explain the perceived or demonstrated effectiveness of programmes to improve health-related outcomes in older people living in care homes. Methods/Design: A realist review approach will be used to develop a theoretical understanding of what works when, why and in what circumstances. Elements of service models of interest include those that focus on assessment and management of residents’ health, those that use strategies to encourage closer working between visiting health care providers and care home staff, and those that address system-wide issues about access to assessment and treatment. These will include studies on continence, dignity, and speech and language assessment as well as interventions to promote person centred dementia care, improve strength and mobility, and nutrition. The impact of these interventions and their different mechanisms will be considered in relation to five key outcomes: residents’ medication use, use of out of hours’ services, hospital admissions (including use of Accident and Emergency) and length of hospital stay, costs and user satisfaction. An iterative three-stage approach will be undertaken that is stakeholder-driven and optimises the knowledge and networks of the research team. Discussion: This realist review will explore why and for whom different approaches to providing health care to residents in care homes improves access to health care in the five areas of interest. It will inform commissioning decisions and be the basis for further research. This systematic review protocol is registered on the PROSPERO database reference number: CRD42014009112NIHR Health Services & Delivery Research Programme. Project number 11/1021/0

Application of the MEGNO technique to the dynamics of Jovian irregular satellites

We apply the MEGNO (Mean Exponential Growth of Nearby Orbits) technique to the dynamics of Jovian irregular satellites. We demonstrate the efficiency of applying the MEGNO indicator to generate a mapping of relevant phase-space regions occupied by observed jovian irregular satellites. The construction of MEGNO maps of the Jovian phase-space region within its Hill-sphere is addressed and the obtained results are compared with previous studies regarding the dynamical stability of irregular satellites. Since this is the first time the MEGNO technique is applied to study the dynamics of irregular satellites we provide a review of the MEGNO theory. We consider the elliptic restricted three-body problem in which Jupiter is orbited by a massless test satellite subject to solar gravitational perturbations. The equations of motion of the system are integrated numerically and the MEGNO indicator computed from the systems variational equations. An unprecedented large set of initial conditions are studied to generate the MEGNO maps. The chaotic nature of initial conditions are demonstrated by studying a quasi-periodic orbit and a chaotic orbit. As a result we establish the existence of several high-order mean-motion resonances detected for retrograde orbits along with other interesting dynamical features. The computed MEGNO maps allows to qualitatively differentiate between chaotic and quasi-periodic regions of the irregular satellite phase-space given only a relatively short integration time. By comparing with previous published results we can establish a correlation between chaotic regions and corresponding regions of orbital instability.Comment: 15 pages, 13 figures, 2 tables, submitted to MNRA