449 research outputs found

    The Future of Radio Revisited: Expert Perspectives and Future Scenarios for Radio Media in 2025

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    In 2005-2006 the research group DRACE (Digital Radio Cultures in Europe) performed a study on how 43 people in key positions related to the radio industry in four European countries and Canada viewed the future of radio and which delivery technologies they considered would be most successful. In addition, it analyzed the motives and reasons why certain technologies were seen as more promising than others. Finally, it presented four different future scenarios for radio media. The study was published in the Journal of Radio and Audio Media, May 2008. In 2005 the future of radio was considered much less obvious and clear than it appeared 10 years previously. Instead of a transition from analog to digital audio broad- casting (DAB), there was a selection of alternative technological options for digital audio delivery. When looking back from 2015 and considering the results of expert interviews, the project group about Public Service Media in the HERA project: Transnational Radio Encounters found interesting perspectives in replicating this study – now looking forward to 2025. By using the same questionnaire and interviewing the same experts (or new persons in the same positions) they could both confront the predictions with the present situation, looking for technological, regulatory, policy based, user oriented contexts. Furthermore, they could ask the experts to look ten years forward from now. Besides from the interviews, desk studies were in order to explore the national similarities and differences as background for the analysis of the scenarios for the 2015 and 2025 studies. This comparative study involves Denmark, Finland, Germany, Ireland and the UK

    Efficacy of acute administration of inhaled argon on traumatic brain injury in mice

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    BACKGROUND: Whilst there has been progress in supportive treatment for traumatic brain injury (TBI), specific neuroprotective interventions are lacking. Models of ischaemic heart and brain injury show the therapeutic potential of argon gas, but it is still not known whether inhaled argon (iAr) is protective in TBI. We tested the effects of acute administration of iAr on brain oedema, tissue micro-environmental changes, neurological functions, and structural outcome in a mouse model of TBI. METHODS: Anaesthetised adult C57BL/6J mice were subjected to severe TBI by controlled cortical impact. Ten minutes after TBI, the mice were randomised to 24 h treatments with iAr 70%/O2 30% or air (iCtr). Sensorimotor deficits were evaluated up to 6 weeks post-TBI by three independent tests. Cognitive function was evaluated by Barnes maze test at 4 weeks. MRI was done to examine brain oedema at 3 days and white matter damage at 5 weeks. Microglia/macrophages activation and functional commitment were evaluated at 1 week after TBI by immunohistochemistry. RESULTS: iAr significantly accelerated sensorimotor recovery and improved cognitive deficits 1 month after TBI, with less white matter damage in the ipsilateral fimbria and body of the corpus callosum. Early changes underpinning protection included a reduction of pericontusional vasogenic oedema and of the inflammatory response. iAr significantly reduced microglial activation with increases in ramified cells and the M2-like marker YM1. CONCLUSIONS: iAr accelerates recovery of sensorimotor function and improves cognitive and structural outcome 1 month after severe TBI in adult mice. Early effects include a reduction of brain oedema and neuroinflammation in the contused tissue

    Effects of copper on larvae of the marbled crab Pachygrapsus marmoratus (Decapoda, Grapsidae): toxicity test and biochemical marker responses

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    The importance of trace elements in ecotoxicological investigations is a well-known issue when monitoring polluted areas such as commercial harbors. Copper represents one of the most common metal contaminants, often detected in these areas as it is widely employed in various fields and has many sources of inflow in the marine environment. Pachygrapsus marmoratus is a widespread intertidal crab species that has been extensively studied in ecology, ethology and population genetics. Ecotoxicological studies have also been performed, exclusively on the adult stage. In the present study we investigated the mortality and biochemical (oxidative stress and neurotoxicity) responses of P. marmoratus larvae exposure to environmental relevant concentration of copper. Results showed dose-dependent responses in terms of larval mortality, with a calculated LC50 value of 0.5 mg/L of Cu2+. The LC50 concentration was used as the starting point for subsequent biochemical response evaluation. Results also demonstrated dose-dependent activation of antioxidant systems assuming a compensatory antioxidant activity to prevent higher cellular damage when larvae were exposed to the highest concentrations of copper. Moreover, a significant enhancement of neurotransmitter activities was observed, assuming a possible direct interaction of copper with the enzymes or an increase of free copper ion aliquot into the cells.publishe

    Coronal properties of G-type stars in different evolutionary phases

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    We report on the analysis of XMM-Newton observations of three G-type stars in very different evolutionary phases: the weak-lined T Tauri star HD 283572, the Zero Age Main Sequence star EK Dra and the Hertzsprung-gap giant star 31 Com. They all have high X-ray luminosity (10^31 erg/s for HD 283572 and 31 Com and 10^30 erg/s for EK Dra). We compare the Emission Measure Distributions (EMDs) of these active coronal sources, derived from high-resolution XMM-Newton grating spectra, as well as the pattern of elemental abundances vs. First Ionization Potential (FIP). We also perform time-resolved spectroscopy of a flare detected by XMM from EK Dra. We interpret the observed EMDEMDs as the result of the emission of ensembles of magnetically confined loop-like structures with different apex temperatures. Our analysis indicates that the coronae of HD 283572 and 31 Com are very similar in terms of dominant coronal magnetic structures, in spite of differences in the evolutionary phase, surface gravity and metallicity. In the case of EK Dra the distribution appears to be slightly flatter than in the previous two cases, although the peak temperature is similar.Comment: 15 pages, 13 Postscript figures, to be published in A&

    Differential Emission Measures from the Regularized Inversion of Hinode and SDO data

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    We develop and apply an enhanced regularization algorithm, used in RHESSI X-ray spectral analysis, to constrain the ill-posed inverse problem that is determining the DEM from solar observations. We demonstrate this computationally fast technique applied to a range of DEM models simulating broadband imaging data from SDO/AIA and high resolution line spectra from Hinode/EIS, as well as actual active region observations with Hinode/EIS and XRT. As this regularization method naturally provides both vertical and horizontal (temperature resolution) error bars we are able to test the role of uncertainties in the data and response functions. The regularization method is able to successfully recover the DEM from simulated data of a variety of model DEMs (single Gaussian, multiple Gaussians and CHIANTI DEM models). It is able to do this, at best, to over four orders of magnitude in DEM space but typically over two orders of magnitude from peak emission. The combination of horizontal and vertical error bars and the regularized solution matrix allows us to easily determine the accuracy and robustness of the regularized DEM. We find that the typical range for the horizontal errors is Δ\DeltalogT0.10.5T\approx 0.1 -0.5 and this is dependent on the observed signal to noise, uncertainty in the response functions as well as the source model and temperature. With Hinode/EIS an uncertainty of 20% greatly broadens the regularized DEMs for both Gaussian and CHIANTI models although information about the underlying DEMs is still recoverable. When applied to real active region observations with Hinode/EIS and XRT the regularization method is able to recover a DEM similar to that found via a MCMC method but in considerably less computational time.Comment: 15 pages, 17 figures, accepted for publication in A&

    EIT and TRACE responses to flare plasma

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    Aims: To understand the contribution of active region and flare plasmas to the λ\lambda195 channels of SOHO/EIT (Extreme-ultraviolet Imaging Telescope) and TRACE (Transition Region and Coronal Explorer). Methods: We have analysed an M8 flare simultaneously observed by the Coronal Diagnostic Spectrometer (CDS), EIT, TRACE and RHESSI. We obtained synthetic spectra for the flaring region and an outer region using the differential emission measures (DEM) of emitting plasma based on CDS and RHESSI observations and the CHIANTI atomic database. We then predicted the EIT and TRACE count rates. Results: For the flaring region, both EIT and TRACE images taken through the λ\lambda195 filter are dominated by Fe XXIV{\rm XXIV} (formed at about 20 MK). However, in the outer region, the emission was primarily due to the FeXII{\rm XII}, with substantial contributions from other lines. The average count rate for the outer region was within 25% the observed value for EIT, while for TRACE it was a factor of two higher. For the flare region, the predicted count rate was a factor of two (in case of EIT) and a factor of three (in case of TRACE) higher than the actual count rate. Conclusions: During a solar flare, both TRACE and EIT λ\lambda195 channels are found to be dominated by Fe XXIV{\rm XXIV} emission. Reasonable agreement between predictions and observations is found, however some discrepancies need to be further investigated.Comment: 6 pages, 4 figure

    Challenges in the Diagnosis and Management of Acquired Nontraumatic Urethral Strictures in Boys in Yaoundé, Cameroon

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    Introduction. Urethral strictures in boys denote narrowing of the urethra which can be congenital or acquired. In case of acquired strictures, the etiology is iatrogenic or traumatic and rarely infectious or inflammatory. The aim of this study was to highlight the diagnostic and therapeutic difficulties of acquired nontraumatic urethral strictures in boys in Yaoundé, Cameroon. Methodology. The authors report five cases of nontraumatic urethral strictures managed at the Pediatric Surgery Department of the YGOPH over a two-year period (November 2012–November 2014). In order to confirm the diagnosis of urethral stricture, all patients were assessed with both cystourethrography and urethrocystoscopy. Results. In all the cases the urethra was inflammatory with either a single or multiple strictures. The surgical management included internal urethrotomy (n=1), urethral dilatation (n=1), vesicostomy (n=2), and urethral catheterization (n=3). With a median follow-up of 8.2 months (4–16 months) all patients remained symptoms-free. Conclusion. The authors report the difficulties encountered in the diagnosis and management of nontraumatic urethral strictures in boys at a tertiary hospital in Yaoundé, Cameroon. The existence of an inflammatory etiology of urethral strictures in boys deserves to be considered
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