3,974 research outputs found

    Testing the relation between ADHD and hyperfocus experiences

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    BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) has been associated with hyperfocus, a transient experience of enhanced attentional focus and diminished awareness of time and the environment. AIMS: This study aims to investigate the association between the frequency, duration and pervasiveness of hyperfocus across different situations in adults with and without ADHD. METHOD AND PROCEDURES: Within a healthy sample (n = 1124), we analysed correlations between scores on the ADHD Rating Scale and self-reports of frequency, duration and pervasiveness of hyperfocus. An ADHD patient group (n = 78) was compared to matched healthy participants on all hyperfocus variables. OUTCOMES AND RESULTS: In healthy adults, the frequency of hyperfocus was positively correlated with ADHD traits; older age and higher education were correlated with fewer hyperfocus occurrences in a smaller number of situations. ADHD patients and matched controls did not differ in the occurrence, frequency, duration and pervasiveness of hyperfocus, but hyperfocus was less likely to occur in educational and social situations in ADHD patients. CONCLUSIONS AND IMPLICATIONS: Hyperfocus experiences are not specific of ADHD patients. The divergent findings might reflect multiple hyperfocus dimensions (situational and motivational) assessed in different studies which need to be addressed in future research

    Enhancing frequency stability by integrating nonconventional power sources through multi-terminal HVDC grid

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    The 2050 targets established by the EU will foster both larger penetration of renewable energy, especially wind power, and more cross–border interconnections. Moreover, this new framework requires the non-conventional power sources and power converter-based systems to be responsible for the duties traditionally carried out by conventional synchronous generators as frequency support. This paper presents how different power-electronic based technologies can provide frequency support individually and in a coordinated manner (with different priority given by the deadbands) ensuring a stable operation. The implemented scenarios push the system to the limits to exploit potential bottlenecks, and demonstrating how joint regulation of the power electronic based technologies enhances the frequency stability of the AC synchronous areas. The different control schemes and their interaction are investigated in Cigre DC grid benchmark adapted for frequency stability studies and implemented in Matlab/Simulink simulation tool. This modified grid includes 5-terminal HVDC grid with two offshore wind farms and three AC networks including battery and onshore wind farms

    Spotting the differences between active and non-active twin galaxies on kpc-scales. A pilot study

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    We present a pilot study aimed to identify large-scale galaxy properties that could play a role in activating a quiescent nucleus. To do so, we compare the properties of two isolated nearby active galaxies and their non-active twins selected from the Calar Alto Legacy Integral Field Area (CALIFA) survey. This pilot sample includes two barred and two unbarred galaxies. We characterise the stellar and ionised gas kinematics and also their stellar content. We obtain simple kinematic models by fitting the full stellar and ionised gas velocity fields and just the approaching/receding sides. We find that the analysed active galaxies present lopsided disks and higher values of the global stellar angular momentum (λR\lambda_{R}) than their non-active twins. This could be indicating that the stellar disks of the AGN gained angular momentum from the inflowing gas that triggered the nuclear activity. The inflow of gas could have been produced by a twisted disk instability in the case of the unbarred AGN, and by the bar in the case of the barred AGN. In addition, we find that the central regions of the studied active galaxies show older stellar populations than their non-active twins. The next step is to statistically explore these galaxy properties in a larger sample of twin galaxies.Comment: 24 pages, 24 figures. Accepted by MNRA

    Morphology of coronary artery lesions assessed by virtual histology intravascular ultrasound tissue characterization and fractional flow reserve

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    Fractional flow reserve (FFR) is an index of the physiological significance of a coronary stenosis. Patients who have lesions with a FFR of >0.80, even optimally treated with medication, have however a MACE rate ranging from 8 to 21%. Coronary plaques at high risk of rupture and clinical events can be also identified by virt

    Stellar Population gradients in galaxy discs from the CALIFA survey

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    While studies of gas-phase metallicity gradients in disc galaxies are common, very little has been done in the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. Contrary to this, the values of both age and metallicity at \sim2.5 scale-lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients in galaxies with without bars. We discuss possible scenarios that can lead to this absence of difference.Comment: 24 pages, 17 figures, accepted for publication in A&

    The Mass-Metallicity relation explored with CALIFA: I. Is there a dependence on the star formation rate?

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    We present the results on the study of the global and local M-Z relation based on the first data available from the CALIFA survey (150 galaxies). This survey provides integral field spectroscopy of the complete optical extent of each galaxy (up to 2-3 effective radii), with enough resolution to separate individual HII regions and/or aggregations. Nearly \sim3000 individual HII regions have been detected. The spectra cover the wavelength range between [OII]3727 and [SII]6731, with a sufficient signal-to-noise to derive the oxygen abundance and star-formation rate associated with each region. In addition, we have computed the integrated and spatially resolved stellar masses (and surface densities), based on SDSS photometric data. We explore the relations between the stellar mass, oxygen abundance and star-formation rate using this dataset. We derive a tight relation between the integrated stellar mass and the gas-phase abundance, with a dispersion smaller than the one already reported in the literature (σΔlog(O/H)=\sigma_{\Delta{\rm log(O/H)}}=0.07 dex). Indeed, this dispersion is only slightly larger than the typical error derived for our oxygen abundances. However, we do not find any secondary relation with the star-formation rate, other than the one induced due to the primary relation of this quantity with the stellar mass. We confirm the result using the \sim3000 individual HII regions, for the corresponding local relations. Our results agree with the scenario in which gas recycling in galaxies, both locally and globally, is much faster than other typical timescales, like that of gas accretion by inflow and/or metal loss due to outflows. In essence, late-type/disk dominated galaxies seem to be in a quasi-steady situation, with a behavior similar to the one expected from an instantaneous recycling/closed-box model.Comment: 19 Pages, 8 figures, Accepted for Publishing in Astronomy and Astrophysics (A&A

    A Feasibility Study of Quantifying Longitudinal Brain Changes in Herpes Simplex Virus (HSV) Encephalitis Using Magnetic Resonance Imaging (MRI) and Stereology.

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    OBJECTIVES: To assess whether it is feasible to quantify acute change in temporal lobe volume and total oedema volumes in herpes simplex virus (HSV) encephalitis as a preliminary to a trial of corticosteroid therapy. METHODS: The study analysed serially acquired magnetic resonance images (MRI), of patients with acute HSV encephalitis who had neuroimaging repeated within four weeks of the first scan. We performed volumetric measurements of the left and right temporal lobes and of cerebral oedema visible on T2 weighted Fluid Attenuated Inversion Recovery (FLAIR) images using stereology in conjunction with point counting. RESULTS: Temporal lobe volumes increased on average by 1.6% (standard deviation (SD 11%) in five patients who had not received corticosteroid therapy and decreased in two patients who had received corticosteroids by 8.5%. FLAIR hyperintensity volumes increased by 9% in patients not receiving treatment with corticosteroids and decreased by 29% in the two patients that had received corticosteroids. CONCLUSIONS: This study has shown it is feasible to quantify acute change in temporal lobe and total oedema volumes in HSV encephalitis and suggests a potential resolution of swelling in response to corticosteroid therapy. These techniques could be used as part of a randomized control trial to investigate the efficacy of corticosteroids for treating HSV encephalitis in conjunction with assessing clinical outcomes and could be of potential value in helping to predict the clinical outcomes of patients with HSV encephalitis

    TOpic: rare and special cases, the real "Strange cases"

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    Introduction: The bladder hernia represents approximately 1-3% of all inguinal hernias, where patients aged more than 50 years have a higher incidence (10%). Many factors contribute to the development of a bladder hernia, including the presence of a urinary outlet obstruction causing chronic bladder distention, the loss of bladder tone, pericystitis, the perivesical bladder fat protrusion and the obesity
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