3,286 research outputs found

    Uncomfortable images produce non-sparse responses in a model of primary visual cortex

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    The processing of visual information by the nervous system requires significant metabolic resources. To minimise the energy needed, our visual system appears to be optimised to encode typical natural images as efficiently as possible. One consequence of this is that some atypical images will produce inefficient, non-optimal responses.Here, we show that images that are reported to be uncomfortable to view, and that can trigger migraine attacks and epileptic seizures, produce relatively non-sparse responses in a model of the primary visual cortex. In comparison to the responses to typical inputs, responses to aversive images were larger and less sparse. We propose that this difference in the neural population response may be one cause of visual discomfort in the general population, and can produce more extreme responses in clinical populations such as migraine and epilepsy sufferers

    Extended [O II] emission around IC 418 and RX Puppis

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    An optical spectrophotometric survey of abundances in Magellanic Cloud Planetary Nebulae

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    Optical spectroscopic data for 71 Planetary Nebulae (PN) in the Large and Small Magellanic Clouds have been analysed. The line fluxes have been used to determine nebular temperatures, densities, and the abundances of He, N, O, Ne, and Ar, relative to H. In our sample there are 12 nebulae with N/O≽0.5, resembling Peimbert's Type I PN; six low-excitation (LE) objects [1≼I(5007)/I(Hβ)≼4]; and four very-low-excitation (VLE) nebulae [I(Hβ)>I(5007)], similar to the Galactic VLE class. Mean abundances have been calculated for the nebulae not in these special groups. After correction for collisional excitation contributions to the nebular He I lines, PN in the SMC and LMC yield mass fractions of Y=0.249±0.025 and Y=0.258±0.015, respectively. Compared with PN in our own Galaxy, the abundances of Ne and Ar, which are the elements in our sample least affected by nucleosynthesis, are lower by 0.6 and 0.35 dex for the SMC and LMC respectively. The oxygen and neon abundances in the Magellanic Cloud PN are the same as those previously found for H II regions in the LMC and SMC, but the nitrogen in PN is enhanced by 0.9 and 1.0 dex in each galaxy, respectively. This is found to be consistent with the processing of all of the original carbon to nitrogen by the CN cycle, operating in the progenitor stars at the time of the first dredge-up. This process seems to have operated much more efficiently in the metal-poor Magellanic Clouds than in the Milky Way, in agreement with theoretical predictions. Five Wolf–Rayet central stars are detected in the sample (two SMC, three LMC). The frequency of occurrence of these helium-rich central stars in low- and medium-excitation PN (15 per cent) is very similar to that of helium-rich white dwarfs in the solar neighbourhood, suggesting that events at the end of the AGB phase may be reponsible for the observed fractions of helium- and hydrogen-rich white dwarf stars

    Neural Decision Boundaries for Maximal Information Transmission

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    We consider here how to separate multidimensional signals into two categories, such that the binary decision transmits the maximum possible information transmitted about those signals. Our motivation comes from the nervous system, where neurons process multidimensional signals into a binary sequence of responses (spikes). In a small noise limit, we derive a general equation for the decision boundary that locally relates its curvature to the probability distribution of inputs. We show that for Gaussian inputs the optimal boundaries are planar, but for non-Gaussian inputs the curvature is nonzero. As an example, we consider exponentially distributed inputs, which are known to approximate a variety of signals from natural environment.Comment: 5 pages, 3 figure

    Predicting participation in group parenting education in an Australian sample: The role of attitudes, norms, and control factors

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    We examined the theory of planned behavior (TPB) in predicting intentions to participate in group parenting education. One hundred and seventy-six parents (138 mothers and 38 fathers) with a child under 12 years completed TPB items assessing attitude, subjective norms, perceived behavioral control (PBC), and two additional social influence variables (self-identity and group norm). Regression analyses supported the TPB predictors of participation intentions with self-identity and group norm also significantly predicting intentions. These findings offer preliminary support for the TPB, along with additional sources of social influence, as a useful predictive model of participation in parenting education

    Mid-infrared evolution of eta Carinae from 1968 to 2018

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    η Car is one of the most luminous and massive stars in our Galaxy and is the brightest mid-IR source in the sky outside our solar system. Since the late 1990s, the central source has dramatically brightened at UV and optical wavelengths. This might be explained by a decrease in circumstellar dust extinction. We aim to establish the mid-IR flux evolution and further our understanding of the star’s UV and optical brightening. Mid-IR images from 8−20 µm were obtained in 2018 with VISIR at the Very Large Telescope. Archival data from 2003 and 2005 were retrieved from the ESO Science Archive Facility, and historical records were collected from publications. We present mid-IR images of η Car with the highest angular resolution to date at the corresponding wavelengths (≥0.2200). We reconstruct the mid-IR evolution of the spectral energy distribution of the spatially integrated Homunculus nebula from 1968 to 2018 and find no long-term changes. The bolometric luminosity of η Car has been stable over the past five decades. We do not observe a long-term decrease in the mid-IR flux densities that could be associated with the brightening at UV and optical wavelengths, but circumstellar dust must be declining in our line of sight alone. Short-term flux variations within about 25% of the mean levels could be present

    Telecare motivational interviewing for diabetes patient education and support : a randomised controlled trial based in primary care comparing nurse and peer supporter delivery

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    Background: There is increasing interest in developing peer-led and 'expert patient'-type interventions, particularly to meet the support and informational needs of those with long term conditions, leading to improved clinical outcomes, and pressure relief on mainstream health services. There is also increasing interest in telephone support, due to its greater accessibility and potential availability than face to face provided support. The evidence base for peer telephone interventions is relatively weak, although such services are widely available as support lines provided by user groups and other charitable services. Methods/Design: In a 3-arm RCT, participants are allocated to either an intervention group with Telecare service provided by a Diabetes Specialist Nurse (DSN), an intervention group with service provided by a peer supporter (also living with diabetes), or a control group receiving routine care only. All supporters underwent a 2-day training in motivational interviewing, empowerment and active listening skills to provide telephone support over a period of up to 6 months to adults with poorly controlled type 2 diabetes who had been recommended a change in diabetes management (i.e. medication and/or lifestyle changes) by their general practitioner (GP). The primary outcome is self-efficacy; secondary outcomes include HbA1c, total and HDL cholesterol, blood pressure, body mass index, and adherence to treatment. 375 participants (125 in each arm) were sought from GP practices across West Midlands, to detect a difference in self-efficacy scores with an effect size of 0.35, 80% power, and 5% significance level. Adults living with type 2 diabetes, with an HbA1c > 8% and not taking insulin were initially eligible. A protocol change 10 months into the recruitment resulted in a change of eligibility by reducing HbA1c to > 7.4%. Several qualitative studies are being conducted alongside the main RCT to describe patient, telecare supporter and practice nurse experience of the trial. Discussion and implications of the research: With its focus on self-management and telephone peer support, the intervention being trialled has the potential to support improved self-efficacy and patient experience, improved clinical outcomes and a reduction in diabetes-related complications

    Understanding innovators' experiences of barriers and facilitators in implementation and diffusion of healthcare service innovations: A qualitative study

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    This article is made available through the Brunel Open Access Publishing Fund - Copyright @ 2011 Barnett et al.Background: Healthcare service innovations are considered to play a pivotal role in improving organisational efficiency and responding effectively to healthcare needs. Nevertheless, healthcare organisations encounter major difficulties in sustaining and diffusing innovations, especially those which concern the organisation and delivery of healthcare services. The purpose of the present study was to explore how healthcare innovators of process-based initiatives perceived and made sense of factors that either facilitated or obstructed the innovation implementation and diffusion. Methods: A qualitative study was designed. Fifteen primary and secondary healthcare organisations in the UK, which had received health service awards for successfully generating and implementing service innovations, were studied. In-depth, semi structured interviews were conducted with the organisational representatives who conceived and led the development process. The data were recorded, transcribed and thematically analysed. Results: Four main themes were identified in the analysis of the data: the role of evidence, the function of inter-organisational partnerships, the influence of human-based resources, and the impact of contextual factors. "Hard" evidence operated as a proof of effectiveness, a means of dissemination and a pre-requisite for the initiation of innovation. Inter-organisational partnerships and people-based resources, such as champions, were considered an integral part of the process of developing, establishing and diffusing the innovations. Finally, contextual influences, both intra-organisational and extra-organisational were seen as critical in either impeding or facilitating innovators' efforts. Conclusions: A range of factors of different combinations and co-occurrence were pointed out by the innovators as they were reflecting on their experiences of implementing, stabilising and diffusing novel service initiatives. Even though the innovations studied were of various contents and originated from diverse organisational contexts, innovators' accounts converged to the significant role of the evidential base of success, the inter-personal and inter-organisational networks, and the inner and outer context. The innovators, operating themselves as important champions and being often willing to lead constructive efforts of implementation to different contexts, can contribute to the promulgation and spread of the novelties significantly.This research was supported financially by the Multidisciplinary Assessment of Technology Centre for Healthcare (MATCH)

    Far Ultraviolet Spectroscopic Explorer Spectroscopy of the O VI Resonance Doublet in Sand 2 (WO)

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    We present Far Ultraviolet Spectroscopic Explorer spectroscopy of Sand 2, an LMC WO-type Wolf-Rayet star, revealing the O VI resonance P Cygni doublet at 1032-1038 Å. These data are combined with Hubble Space Telescope Faint Object Spectrograph ultraviolet and Mount Stromlo 2.3 m optical spectroscopy and analyzed using a spherical, non-LTE, line-blanketed code. Our study reveals exceptional stellar parameters: T* ~ 150,000 K, v∞ = 4100 km s-1, log(L/L☉) = 5.3, andimg1.gif = 1 × 10-5 M☉ yr-1, if we adopt a volume filling factor of 10%. Elemental abundances of C/He ~ 0.7 ± 0.2 and O/He ~ 0.15img2.gif by number qualitatively support previous recombination line studies. We confirm that Sand 2 is more chemically enriched in carbon than LMC WC stars and that it is expected to undergo a supernova explosion within the next 5 × 104 yr

    Minocycline and the risk of acute psychiatric events in adolescence: A self-controlled case series

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    BACKGROUND: Minocycline has neurological anti-inflammatory properties and has been hypothesised to have antipsychotic effects. AIM: The aim of this study was to investigate, using routinely collected United Kingdom primary health care data, whether adolescent men and women are more or less likely to receive an urgent psychiatric referral during treatment for acne with minocycline compared with periods of non-treatment. METHOD: A self-controlled case series using United Kingdom Clinical Practice Research Datalink to calculate the incidence rate ratio of urgent psychiatric referrals for individuals, comparing periods during which minocycline was prescribed with unexposed periods, adjusted for age. RESULTS: We found 167 individuals who were at the time exposed to minocycline for a mean of 99 days and who received an urgent psychiatric referral. There was no difference in psychiatric referral risk during periods of exposure compared with periods of non-exposure: incidence rate ratio first 6 weeks of exposure 1.96, 95% confidence interval 0.82-4.71, p=0.132; incidence rate ratio remaining exposure period=1.97, 95% confidence interval 0.86-4.47, p=0.107. CONCLUSIONS: We found no evidence in support of a protective effect of minocycline against severe psychiatric symptoms in adolescence
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