1,376 research outputs found

    The H.E.S.S. central data acquisition system

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    The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric Cherenkov Telescopes (IACTs) located in the Khomas Highland in Namibia. It measures cosmic gamma rays of very high energies (VHE; >100 GeV) using the Earth's atmosphere as a calorimeter. The H.E.S.S. Array entered Phase II in September 2012 with the inauguration of a fifth telescope that is larger and more complex than the other four. This paper will give an overview of the current H.E.S.S. central data acquisition (DAQ) system with particular emphasis on the upgrades made to integrate the fifth telescope into the array. At first, the various requirements for the central DAQ are discussed then the general design principles employed to fulfil these requirements are described. Finally, the performance, stability and reliability of the H.E.S.S. central DAQ are presented. One of the major accomplishments is that less than 0.8% of observation time has been lost due to central DAQ problems since 2009.Comment: 17 pages, 8 figures, published in Astroparticle Physic

    Zur Sterblichkeitsdifferenz von Männern im Ost-West-Vergleich

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    Die Untersuchung der Sterblichkeit der sozialversicherungspflichtigen Beschäftigten des Jahres 2004 deckt die Gründe für die Unterschiede der Lebenserwartung bei Männern im Ost-West-Vergleich auf. Es wird gezeigt, dass die bestehenden strukturellen Unterschiede des Arbeitsmarktes in Ost- und Westdeutschland die Lebenserwartungsdifferenz bei Männern im Alter bis 65 Jahre erklären können. Die multivariate Analyse von Individualdaten der 20 Millionen "Aktiv Versicherten" (Datensätze des Forschungsdatenzentrum der Rentenversicherung (FDZ-RV)) zeigt, dass die Berücksichtigung der Merkmale Beschäftigung, Arbeitslosigkeit, Selbstständigkeit, Versicherungsart und Staatsbürgerschaft geeignet sind, eine bis zu 30 % erhöhte Sterblichkeit der ostdeutschen Männer im Altersbereich von 35 bis 55 Jahre zu erklären. Die Differenzen sind ein Ergebnis der unterschiedlichen Arbeitsmarktlage und der damit verbundenen kumulativen Migration in den letzten 30 Jahren.Germany, Germany (Alte Bundesländer), Germany (Neue Bundesländer), life expectancy, male mortality, unemployment, working-age population

    Electrostatic colloid-membrane complexation

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    We investigate numerically and on the scaling level the adsorption of a charged colloid on an oppositely charged flexible membrane. We show that the long ranged character of the electrostatic interaction leads to a wrapping reentrance of the complex as the salt concentration is varied. The membrane wrapping depends on the size of the colloid and on the salt concentration and only for intermediate salt concentration and colloid sizes we find full wrapping. From the scaling model we derive simple relations for the phase boundaries between the different states of the complex, which agree well with the numerical minimization of the free energy.Comment: 7 page, 11 figure

    Role of a Transbilayer pH Gradient in the Membrane Fusion Activity of the Influenza Virus Hemagglutinin: Use of the R18 Assay to Monitor Membrane Merging

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    It had been suggested that influenza virus-mediated membrane fusion might be dependent on a pH gradient across a target membrane. We have designed experiments in which this issue could be addressed. Two populations of liposomes were prepared, both simulating the plasma membrane of target cells, but with the pH of the internal aqueous medium buffered either at pH 7.4 (physiological cytosol pH) or at pH 5.0 (endosomal pH at which influenza virus displays maximal fusion activity). By monitoring fusion using the R18 assay, we found that the internal pH of the target liposomes did not influence membrane merging as mediated by the influenza virus hemagglutinin, thus demonstrating that a transmembrane pH gradient is not required in this fusion process

    S-COL: A Copernican turn for the development of flexibly reusable collaboration scripts

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    Collaboration scripts are usually implemented as parts of a particular collaborative-learning platform. Therefore, scripts of demonstrated effectiveness are hardly used with learning platforms at other sites, and replication studies are rare. The approach of a platform-independent description language for scripts that allows for easy implementation of the same script on different platforms has not succeeded yet in making the transfer of scripts feasible. We present an alternative solution that treats the problem as a special case of providing support on top of diverse Web pages: In this case, the challenge is to trigger support based on the recognition of a Web page as belonging to a specific type of functionally equivalent pages such as the search query form or the results page of a search engine. The solution suggested has been implemented by means of a tool called S-COL (Scripting for Collaborative Online Learning) and allows for the sustainable development of scripts and scaffolds that can be used with a broad variety of content and platforms. The tool’s functions are described. In order to demonstrate the feasibility and ease of script reuse with S-COL, we describe the flexible re-implementation of a collaboration script for argumentation in S-COL and its adaptation to different learning platforms. To demonstrate that a collaboration script implemented in S-COL can actually foster learning, an empirical study about the effects of a specific script for collaborative online search on learning activities is presented. The further potentials and the limitations of the S-COL approach are discussed

    Field anaesthesia of the African elephant (Loxodonta africana)

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    Immobilisation and anaesthesia of elephants may be required for various reasons, such as the capture, transport and clinical examination of captive animals, e.g. at a zoological park, or for minor surgical procedures. General anaesthesia is required for wound treatment, i.e trunk lacerations and dental surgery, or population control, i.e. laparoscopic vasectomy.http://www.sajaa.co.za/index.php/sajaaam2014mn201

    Hospital postdischarge intervention trialled with family caregivers of older people in Western Australia: potential translation into practice

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    There is lack of a suitable assessment tool that can be used routinely and systematically by hospital staff to address family caregivers' (FCs') support needs. This paper describes a novel approach to identifying and addressing FCs' needs following hospital discharge of the older person receiving care. SETTING AND PARTICIPANTS: FC recruitment occurred on the patient's discharge from a tertiary hospital in Western Australia; 64 completed the study; 80% were female; mean age 63.2 years. INTERVENTION: The Further Enabling Care at Home (FECH) programme was delivered over the telephone by a specially trained nurse and included: support to facilitate understanding of the patient's discharge letter; caregiver support needs assessment and prioritisation of urgent needs; and collaborative guidance, from the nurse, regarding accessing supports. RESULTS: Sixty-four FCs completed the FECH programme. The top three support needs identified by the FCs were: knowing what to expect in the future (52%), knowing who to contact if they were concerned (52%) and practical help in the home (36%). The telephone-based outreach service worked well and was convenient for the nurse and the FCs, and saved on transport, time and money. Most of the FCs appreciated the systematic approach to identify and articulate their needs and were satisfied with the support they received, mainly navigation through the systems, problem solving, self-care strategies, explanation of illness, symptoms and medication and access to after-hours services. CONCLUSIONS: In order to guide services which may consider adopting this systematic approach to supporting FCs and integrating it into their routine practice, this evaluation of the FECH programme has described the processes implemented and highlighted the factors that hindered or facilitated these processes to engage caregivers with appropriate services in a timely manner. Positive feedback indicated that the programme was a useful addition to hospital discharge planning. TRIAL REGISTRATION NUMBER: ACTRN12614001174673; Results

    Spatially resolved X-ray spectroscopy and modeling of the nonthermal emission of the PWN in G0.9+0.1

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    We performed a spatially resolved spectral X-ray study of the pulsar wind nebula (PWN) in the supernova remnant G0.9+0.1. Furthermore we modeled its nonthermal emission in the X-ray and very high energy (VHE, E > 100 GeV) gamma-ray regime. Using Chandra ACIS-S3 data, we investigated the east-west dependence of the spectral properties of G0.9+0.1 by calculating hardness ratios. We analyzed the EPIC-MOS and EPIC-pn data of two on-axis observations of the XMM-Newton telescope and extracted spectra of four annulus-shaped regions, centered on the region of brightest emission of the source. A radially symmetric leptonic model was applied in order to reproduce the observed X-ray emission of the inner part of the PWN. Using the optimized model parameter values obtained from the X-ray analysis, we then compared the modeled inverse Compton (IC) radiation with the published H.E.S.S. gamma-ray data. The spectral index within the four annuli increases with growing distance to the pulsar, whereas the surface brightness drops. With the adopted model we are able to reproduce the characteristics of the X-ray spectra. The model results for the VHE gamma radiation, however, strongly deviate from the H.E.S.S. data.Comment: 8 pages, 7 figures, accepted for publication in Astronomy & Astrophysic
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