Predicting loneliness in older age using two measures of loneliness

Older people are especially vulnerable to loneliness and this has become a major public health concern for people in later life. In this paper, we propose a machine learning based approach to predict loneliness probability using two gradient boosting algorithms, XGBoost and LightGBM. The predictive models are built using data from a large nationally representative sample from, the English Longitudinal Study of Ageing (ELSA) that had seven successive waves (2002–2015). Two measures of loneliness were applied to investigate the impact of different measure strategies on the prediction of loneliness. The models achieved good performance with a high Area Under Curve (AUC) and a low Logarithmic Loss (LogLoss) on the test data, i.e. AUC (0.88) and LogLoss (0.24) using the single-item direct measure of loneliness, and AUC (0.84) and LogLoss (0.31) using the multi-item indirect measure of loneliness. A wide range of variables were investigated to identify significant risk factors associated with loneliness. Specific categories associated with important variables were also recognized by the models. Such information will further enhance our understanding and knowledge of the causes of loneliness in elderly people

The use of data mining methods for the prediction of dementia : evidence from the English longitudinal study of aging

Dementia in older age is a major health concern with the increase in the aging population. Preventive measures to prevent or delay dementia symptoms are of utmost importance. In this study, a large and wide variety of factors from multiple domains were investigated using a large nationally-representative sample of older people from the English Longitudinal Study of Ageing (ELSA). Seven machine learning algorithms were implemented to build predictive models for performance comparison. A simple model ensemble approach was used to combine the prediction results of individual base models to further improve predictive power. A series of important factors in each domain area were identified. The findings from this study provide new evidence on factors that are associated with the dementia in later life. This information will help our understanding of potential risk factors for dementia and identify warning signs of the early stages of dementia. Longitudinal research is required to establish which factors may be causative and which factors may be a consequence of dementia

Statistical analysis of the primary outcome in acute stroke trials

Common outcome scales in acute stroke trials are ordered categorical or pseudocontinuous in structure but most have been analyzed as binary measures. The use of fixed dichotomous analysis of ordered categorical outcomes after stroke (such as the modified Rankin Scale) is rarely the most statistically efficient approach and usually requires a larger sample size to demonstrate efficacy than other approaches. Preferred statistical approaches include sliding dichotomous, ordinal, or continuous analyses. Because there is no best approach that will work for all acute stroke trials, it is vital that studies are designed with a full understanding of the type of patients to be enrolled (in particular their case mix, which will be critically dependent on their age and severity), the potential mechanism by which the intervention works (ie, will it tend to move all patients somewhat, or some patients a lot, and is a common hazard present), a realistic assessment of the likely effect size, and therefore the necessary sample size, and an understanding of what the intervention will cost if implemented in clinical practice. If these approaches are followed, then the risk of missing useful treatment effects for acute stroke will diminish

Dipyridamole plus aspirin versus aspirin alone in the secondary prevention after TIA or stroke: a meta-analysis by risk

Objectives: Our aim was to study the effect of combination therapy with aspirin and dipyridamole (A+D) over aspirin alone (ASA) in secondary prevention after transient ischemic attack or minor stroke of presumed arterial origin and to perform subgroup analyses to identify patients that might benefit most from secondary prevention with A+D. Data sources: The previously published meta-analysis of individual patient data was updated with data from ESPRIT (N=2,739); trials without data on the comparison of A+D versus ASA were excluded. Review methods: A meta-analysis was performed using Cox regression, including several subgroup analyses and following baseline risk stratification. Results: A total of 7,612 patients (5 trials) were included in the analyses, 3,800 allocated to A+D and 3,812 to ASA alone. The trial-adjusted hazard ratio for the composite event of vascular death, non-fatal myocardial infarction and non-fatal stroke was 0.82 (95% confidence interval 0.72-0.92). Hazard ratios did not differ in subgroup analyses based on age, sex, qualifying event, hypertension, diabetes, previous stroke, ischemic heart disease, aspirin dose, type of vessel disease and dipyridamole formulation, nor across baseline risk strata as assessed with two different risk scores. A+D were also more effective than ASA alone in preventing recurrent stroke, HR 0.78 (95% CI 0.68 – 0.90). Conclusion: The combination of aspirin and dipyridamole is more effective than aspirin alone in patients with TIA or ischemic stroke of presumed arterial origin in the secondary prevention of stroke and other vascular events. This superiority was found in all subgroups and was independent of baseline risk. ---------------------------7dc3521430776 Content-Disposition: form-data; name="c14_creators_1_name_family" Halke

On the Correlated X-ray and Optical Evolution of SS Cygni

We have analyzed the variability and spectral evolution of the prototype dwarf nova system SS Cygni using RXTE data and AAVSO observations. A series of pointed RXTE/PCA observations allow us to trace the evolution of the X-ray spectrum of SS Cygni in unprecedented detail, while 6 years of optical AAVSO and RXTE/ASM light curves show long-term patterns. Employing a technique in which we stack the X-ray flux over multiple outbursts, phased according to the optical light curve, we investigate the outburst morphology. We find that the 3-12 keV X-ray flux is suppressed during optical outbursts, a behavior seen previously, but only in a handful of cycles. The several outbursts of SS Cygni observed with the more sensitive RXTE/PCA also show a depression of the X-rays during optical outburst. We quantify the time lags between the optical and X-ray outbursts, and the timescales of the X-ray recovery from outburst. The optical light curve of SS Cygni exhibits brief anomalous outbursts. During these events the hard X-rays and optical flux increase together. The long-term data suggest that the X-rays decline between outburst. Our results are in general agreement with modified disk instability models (DIM), which invoke a two-component accretion flow consisting of a cool optically thick accretion disk truncated at an inner radius, and a quasi-spherical hot corona-like flow extending to the surface of the white dwarf. We discuss our results in the framework of one such model, involving the evaporation of the inner part of the optically thick accretion disk, proposed by Meyer & Meyer-Hofmeister (1994).Comment: 24 pages, 8 figures, 2 tables, accepted for publication in Ap

The Stationary Phase Method for a Wave Packet in a Semiconductor Layered System. The applicability of the method

Using the formal analysis made by Bohm in his book, {\em "Quantum theory"}, Dover Publications Inc. New York (1979), to calculate approximately the phase time for a transmitted and the reflected wave packets through a potential barrier, we calculate the phase time for a semiconductor system formed by different mesoscopic layers. The transmitted and the reflected wave packets are analyzed and the applicability of this procedure, based on the stationary phase of a wave packet, is considered in different conditions. For the applicability of the stationary phase method an expression is obtained in the case of the transmitted wave depending only on the derivatives of the phase, up to third order. This condition indicates whether the parameters of the system allow to define the wave packet by its leading term. The case of a multiple barrier systems is shown as an illustration of the results. This formalism includes the use of the Transfer Matrix to describe the central stratum, whether it is formed by one layer (the single barrier case), or two barriers and an inner well (the DBRT system), but one can assume that this stratum can be comprise of any number or any kind of semiconductor layers.Comment: 15 pages, 4 figures although figure 4 has 5 graph

ORFEUS II and IUE Spectroscopy of EX Hydrae

Using ORFEUS-SPAS II FUV spectra, IUE UV spectra, and archival EUVE deep survey photometry, we present a detailed picture of the behavior of the magnetic cataclysmic variable EX Hydrae. Like HUT spectra of this source, the FUV and UV spectra reveal broad emission lines of He II, C II-IV, N III and V, O VI, Si III-IV, and Al III superposed on a continuum which is blue in the UV and nearly flat in the FUV. Like ORFEUS spectra of AM Her, the O VI doublet is resolved into broad and narrow emission components. Consistent with its behavior in the optical, the FUV and UV continuum flux densities, the FUV and UV broad emission line fluxes, and the radial velocity of the O VI broad emission component all vary on the spin phase of the white dwarf, with the maximum of the FUV and UV continuum and broad emission line flux light curves coincident with maximum blueshift of the broad O VI emission component. On the binary phase, the broad dip in the EUV light curve is accompanied by strong eclipses of the UV emission lines and by variations in both the flux and radial velocity of the O VI narrow emission component. The available data are consistent with the accretion funnel being the source of the FUV and UV continuum and the O VI broad emission component, and the white dwarf being the source of the O VI narrow emission component.Comment: 21 pages, 10 Postscript figures; LaTeX format, uses aaspp4.sty; table2.tex included separately because it must be printed sideways - see instructions in the file; accepted on 1999 Feb 20 for publication in The Astrophysical Journa

Extreme Variability in the Be-Type, Periodic Recurrent X-Ray Transient A0538 - 66: A Highly Eccentric Interacting Binary

We present optical spectroscopy and photometry and IUE spectroscopy of the counterpart of the extremely powerful LMC recurrent X-ray transient A0538 – 66. During one 16.6 day outburst cycle at the end of 1980 December the optical spectra show steadily increasing Balmer and He I emission (indicative of an expanding envelope) superposed on a B2 III–IV spectrum. There is a substantial optical brightness increase of 2 mag at the peak, accompanied by the sudden turn-on of He IIλ 4686. These and other optical spectra show significant radial velocity changes but we can find no clear correlation with the 16.6 day cycle. Further optical and IUE spectra were obtained at the peak of subsequent outbursts, and these show very strong and broad (∼ 5000 km s−1) emission lines. We interpret the system as a ∼ 1 M⊙ compact object in a highly eccentric (e ∼ 0.7) orbit about the ∼ 12 M⊙ B star with a binary period equal to the flare period. Continuum measurements indicate that the emitting region at outburst is several times the size of the B star thus implying that at periastron passage the envelope of the primary is tidally expanded by the neutron star. Although this is now the best example of a growing group of recurrent X-ray transients, A0538 – 66 is unique in its optical behaviour and peak Lx when compared with other galactic X-ray transients and shell/Be stars

Sharing and empathy in digital spaces: qualitative study of online health forums for breast cancer and motor neuron disease. (Amyotrophic Lateral Sclerosis)

Background: The availability of an increasing number of online health forums has altered the experience of living with a health condition, as more people are now able to connect and support one another. Empathy is an important component of peer-to-peer support, although little is known about how empathy develops and operates within online health forums. Objective: The aim of this paper is to explore how empathy develops and operates within two online health forums for differing health conditions: breast cancer and motor neuron disease (MND), also known as amyotrophic lateral sclerosis. Methods: This qualitative study analyzed data from two sources: interviews with forum users and downloaded forum posts. Data were collected from two online health forums provided by UK charities: Breast Cancer Care and the Motor Neurone Disease Association. We analyzed 84 threads from the breast cancer forum and 52 from the MND forum. Threads were purposively sampled to reflect varied experiences (eg, illness stages, topics of conversation, and user characteristics). Semistructured interviews were conducted with 14 Breast Cancer Care forum users and five users of the MND forum. All datasets were analyzed thematically using Braun and Clarke’s six-phase approach and combined to triangulate the analysis. Results: We found that empathy develops and operates through shared experiences and connections. The development of empathy begins outside the forum with experiences of illness onset and diagnosis, creating emotional and informational needs. Users came to the forum and found their experiences and needs were shared and understood by others, setting the empathetic tone and supportive ethos of the forum. The forum was viewed as both a useful and meaningful space in which they could share experiences, information, and emotions, and receive empathetic support within a supportive and warm atmosphere. Empathy operated through connections formed within this humane space based on similarity, relationships, and shared feelings. Users felt a need to connect to users who they felt were like themselves (eg, people sharing the same specific diagnosis). They formed relationships with other users. They connected based on the emotional understanding of ill health. Within these connections, empathic communication flourished. Conclusions: Empathy develops and operates within shared experiences and connections, enabled by structural possibilities provided by the forums giving users the opportunity and means to interact within public, restricted, and more private spaces, as well as within groups and in one-to-one exchanges. The atmosphere and feeling of both sites and perceived audiences were important facilitators of empathy, with users sharing a perception of virtual communities of caring and supportive people. Our findings are of value to organizations hosting health forums and to health professionals signposting patients to additional sources of support