Gamma-Hadron Separation in Very-High-Energy gamma-ray astronomy using a multivariate analysis method

In recent years, Imaging Atmospheric Cherenkov Telescopes (IACTs) have discovered a rich diversity of very high energy (VHE, > 100 GeV) gamma-ray emitters in the sky. These instruments image Cherenkov light emitted by gamma-ray induced particle cascades in the atmosphere. Background from the much more numerous cosmic-ray cascades is efficiently reduced by considering the shape of the shower images, and the capability to reduce this background is one of the key aspects that determine the sensitivity of a IACT. In this work we apply a tree classification method to data from the High Energy Stereoscopic System (H.E.S.S.). We show the stability of the method and its capabilities to yield an improved background reduction compared to the H.E.S.S. Standard Analysis.Comment: 10 pages, 9 figures, accepted for publication in Astroparticle Physic

Fermi-LAT upper limits on gamma-ray emission from colliding wind binaries

Context: Colliding wind binaries (CWBs) are thought to give rise to a plethora of physical processes including acceleration and interaction of relativistic particles. Observation of synchrotron radiation in the radio band confirms there is a relativistic electron population in CWBs. Accordingly, CWBs have been suspected sources of high-energy gamma-ray emission since the COS-B era. Theoretical models exist that characterize the underlying physical processes leading to particle acceleration and quantitatively predict the non-thermal energy emission observable at Earth. Aims: We strive to find evidence of gamma-ray emission from a sample of seven CWB systems: WR 11, WR 70, WR 125, WR 137, WR 140, WR 146, and WR 147. Theoretical modelling identified these systems as the most favourable candidates for emitting gamma-rays. We make a comparison with existing gamma-ray flux predictions and investigate possible constraints. Methods: We used 24 months of data from the Large Area Telescope (LAT) on-board the Fermi Gamma Ray Space Telescope to perform a dedicated likelihood analysis of CWBs in the LAT energy range. Results: We find no evidence of gamma-ray emission from any of the studied CWB systems and determine corresponding flux upper limits. For some CWBs the interplay of orbital and stellar parameters renders the Fermi-LAT data not sensitive enough to constrain the parameter space of the emission models. In the cases of WR140 and WR147, the Fermi-LAT upper limits appear to rule out some model predictions entirely and constrain theoretical models over a significant parameter space. A comparison of our findings to the CWB eta Car is made.Comment: 9 pages, 3 figure

Application of Deep Learning methods to analysis of Imaging Atmospheric Cherenkov Telescopes data

Ground based gamma-ray observations with Imaging Atmospheric Cherenkov Telescopes (IACTs) play a significant role in the discovery of very high energy (E > 100 GeV) gamma-ray emitters. The analysis of IACT data demands a highly efficient background rejection technique, as well as methods to accurately determine the energy of the recorded gamma-ray and the position of its source in the sky. We present results for background rejection and signal direction reconstruction from first studies of a novel data analysis scheme for IACT measurements. The new analysis is based on a set of Convolutional Neural Networks (CNNs) applied to images from the four H.E.S.S. phase-I telescopes. As the H.E.S.S. cameras pixels are arranged in a hexagonal array, we demonstrate two ways to use such image data to train CNNs: by resampling the images to a square grid and by applying modified convolution kernels that conserve the hexagonal grid properties. The networks were trained on sets of Monte-Carlo simulated events and tested on both simulations and measured data from the H.E.S.S. array. A comparison between the CNN analysis to current state-of-the-art algorithms reveals a clear improvement in background rejection performance. When applied to H.E.S.S. observation data, the CNN direction reconstruction performs at a similar level as traditional methods. These results serve as a proof-of-concept for the application of CNNs to the analysis of events recorded by IACTs

Increased neutrophil-lymphocyte ratio in delirium

Aim: Delirium is a common and severe complication among older hospitalized patients. The pathophysiology is poorly understood, but it has been suggested that inflammation and oxidative stress may play a role. The aim of this pilot study was to investigate levels of the neutrophil-lymphocyte ratio (NLR) - a marker of systemic inflammation and oxidative stress - in patients with and without delirium. Methods: This pilot study was performed within a retrospective chart review study that included acutely ill patients, 65 years and older, who were admitted to the ward of geriatrics of the Erasmus University Medical Center. All patients in whom the differential white blood cell (WBC) counts as well as the C-reactive protein (CRP) level were determined within 24 h after admission were included in the present study. Differences in NLR between patients with and without delirium were investigated using univariate analysis of variance, with adjustments for age, sex, comorbidities, CRP level, and total WBC count. Results: Eighty-six patients were included. Thirteen patients were diagnosed with delirium. In adjusted models, higher mean NLR values were found in patients with, than in those without, delirium (9.10 vs 5.18, P=0.003). Conclusion: In this pilot study, we found increased NLR levels in patients with delirium. This finding might suggest that an inadequate response of the immune system and oxidative stress may play a role in the pathogenesis of delirium. Further studies are needed to confirm the association between NLR and delirium

CCS from industrial sources

The literature concerning the application of CCS to industry is reviewed. Costs are presented for different sectors including ``high purity'' (processes which inherently produce a high concentration of CO2), cement, iron and steel, refinery and biomass. The application of CCS to industry is a field which has had much less attention than its application to the electricity production sector. Costs range from less than $2011 10/tCO 2 up to above$ 2011 100/tCO 2 . In the words of a synthesis report from the United Nations Industrial Development Organisation (UNIDO) ``This area has so far not been the focus of discussions and therefore much attention needs to be paid to the application of CCS to industrial sources if the full potential of CCS is to be unlocked''

Developing a patient measure of safety (PMOS)

Background: Tools that proactively identify factors that contribute to accidents have been developed within high-risk industries. Although patients provide feedback on their experience of care in hospitals, there is no existing measure which asks patients to comment on the factors that contribute to patient safety incidents. The aim of the current study was to determine those contributory factors from the Yorkshire Contributory Factors Framework (YCFF) that patients are able to identify in a hospital setting and to use this information to develop a patient measure of safety (PMOS). Methods: Thirty-three qualitative interviews with a representative sample of patients from six units in a teaching hospital in the north of England were carried out. Patients were asked either to describe their most recent/current hospital experience (unstructured) or were asked to describe their experience in relation to specific contributory factors (structured). Responses were coded using the YCFF. Face validity of the PMOS was tested with 12 patients and 12 health professionals, using a 'think aloud' approach, and appropriate revisions made. The research was supported by two patient representatives. Results: Patients were able to comment on/identify 13 of the 20 contributory factors contained within the YCFF domains. They identified contributory factors relating to communication and individual factors more frequently, and contributory factors relating to team factors, and support from central functions less frequently. In addition, they identified one theme not included in the YCFF: dignity and respect. The draft PMOS showed acceptable face validity. Discussion: Patients are able to identify factors which contribute to the safety of their care. The PMOS provides a way of systematically assessing these and has the potential to help health professionals and healthcare organisations understand and identify, safety concerns from the patients' perspective, and, in doing so, make appropriate service improvements

Мирон Кордуба і Микола Андрусяк: до історії взаємин

У статті проаналізовано взаємини українських істориків М. Кордуби та М. Андрусяка, зокрема висвітлено їхні особисті та творчі контакти. Також подано погляди учених на проблеми розвитку української науки, діяльність НТШ та національне книговидання тощо. Охарактеризовано взаємне листування вчених. У додатку до статті вміщено епістолярій М. Кордуби та М. Андрусяка.В статье проанализированы взаимоотношения украинских историков М. Кордубы и Н. Андрусяка, представлены их взгляды на развитие украинской науки, национальное книгоиздание, деятельность Научного общества имени Шевченко во Львове. Охарактеризовано переписку ученых. В приложении к статье помещены письма М. Кордубы и Н. Андрусяка.The article analyzes relationships of the Ukrainian historians M.Korduba and M.Andrusyak, in particular it highlights their personal and professional contacts. Also, the views of scientists on the problems of the Ukrainian science development, activities of Shevchenko Scientific Society and the national book publishing, etc. are given. The correspondence of two scientists is characterized. Correspondence of M. Korduba and M. Andrusiak is given in the appendix to the article