941 research outputs found

    Inbetriebnahme und Leistungstest des Fokalreduktors MOSCA fĂŒr das 3,5--Meter--Teleskop auf dem Calar Alto

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    In der vorliegenden Diplomarbeit werden Eigenschaften des Fokalreduktor--Spektrografen MOSCA gemessen und kritisch bewertet. MOSCA wird am 3,5--Meter--Teleskop des Max--Planck--Instituts fĂŒr Astronomie auf dem Calar Alto in Spanien zum Einsatz kommen. Es wird festgestellt, dass der Einfluss der Biegung auf Direktaufnahmen von bis zu einer Stunde mit ( 0,04 bogensekunden) innerhalb der Spezifikation liegt. Fehler im Aperturenschlitten bewirken eine Positionierungsungenauigkeit von bis zu drei Pixel. Das optische Zentrum und der Abbildungsmaßstab werden bestimmt. Der Maßstab von durchschnittlich ( 21,572 bogeneskunden/mm ) Ă€ndert sich ĂŒber das 11,4 bogenminutenmin * 11,4 bogenminuten große Bildfeld um 4%. Deshalb ist eine Verzeichnungsfunktion bestimmt worden, die eine Positionsbestimmung mit bis zu 0,1 bogensekunden Genauigkeit zulĂ€sst. Die volle Halbwertsbreite eines Sternbildes vergrĂ¶ĂŸert sich infolge von Bildfehlern von der Mitte bis zum Rand des Bildfeldes um 0,17 bogensekunden. Wegen des grossen ÖffnungsverhĂ€ltnisses von ( 1 / 2,7 ) macht sich die gemessene Schieflage des CCD--Chips von 0,11 mm in der AbbildungqualitĂ€t bemerkbar. Der Einsatz und die Funktionsweise eines Fokussierprismas zur schnellen und exakten Fokussierung werden beschrieben. Die Transmissionen der eingebauten Standardfilter und des Gesamtsystems werden bestimmt. FĂŒr den Einsatz als Spektrograf wird die Dispersion der eingebauten Grisms gemessen und fĂŒr die WellenlĂ€ngenkalibration die Spektrallinien der Kalibrationseinheit identifiziert, so dass mit MOSCA eine WellenlĂ€ngengenauigkeit von 0,05 bis 0,79 Angstrom bei einer Bogensekunde Spaltbreite erreicht werden kann. Mit Hilfe von Standardsternen wurde die Effizienz des GerĂ€tes fĂŒr die Spektroskopie gemessen; Sie betrĂ€gt 25 - 36 %

    Structural Stability: On the Prerequisites of Nonviolent Conflict Management

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    The concept of “structural stability” has been gaining prominence in development policy circles. In the EU’s and the OECD Development Assistance Committee’s (OECD DAC) understanding, it describes the ability of societies to handle intra-societal conflict without resorting to violence. This study investigates the preconditions of structural stability and tests their mutual interconnections. Seven dimensions are analyzed: (1) long-term economic growth, (2) environmental security, (3) social equality, (4) governmental effectiveness, (5) democracy, (6) rule of law, and (7) inclusion of identity groups. The postulated mutual enhancement of the seven dimensions is plausible but cannot be proven. The most significant positive relationship appears between “democracy” and “rule of law,” respectively, on the one hand and the dependent variable “violence/ human security” on the other hand. This points to the usefulness of the political concept of structural stability to promote development policy agendas in this area at least. Applications that reach beyond these initial findings will, however, require further research.Structural stability, violence, human security, development aid, conflict management, prerequisites of nonviolence

    What does the global mean OH concentration tell us?

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    International audienceThe global mean OH concentration ([OH]GM ) has been used as an indicator of the atmospheric oxidizing efficiency or its changes over time. It is also used for evaluating the performance of atmospheric chemistry models by comparing with other models or with observationally-based reference [OH]GM levels. We contend that the treatment of this quantity in the recent literature renders it problematic for either of these pur-poses. Several different methods have historically been used to compute [OH]GM: weighting by atmospheric mass or volume, or by the reaction with CH4 or CH3CCl3. In addition, these have been applied over different domains to represent the troposphere. While it is clear that this can lead to inconsistent [OH]GM values, to date there has been no careful assessment of the differences expected when [OH]GM is computed using various weightings and domains. Here these differences are considered using four different 3D OH distributions, along with the weightings mentioned above applied over various atmospheric domains. We find that the [OH]GM values computed based on a given distribution but using different domains for the troposphere can result in differences of 10% or more, while different weightings can lead to differences of up to 30%, comparable to the uncertainty which is commonly stated for [OH]GM or its trend. Thus, at present comparing [OH]GM values or trends from different studies does not provide clearly interpretable information about whether the OH amounts are actually similar or not, except in the few cases where the same weighting and domain have been used in both studies. Furthermore, we find that the only direct indicator of the global atmospheric oxidizing efficiency of OH with respect to a particular gas (e.g. CH4 or CH3CCl3 ) is the [OH]GM value weighted by the reaction with that gas; the mass-weighted and volume-weighted [OH]GM values, in contrast, are generally poor indicators of the atmospheric oxidizing efficiency on a global basis (regionally they are better). We recommend that in future studies the [OH]GM value weighted by the reaction with CH4 , along with the CH4 turnover time, be given as the primary indicators of the atmospheric oxidizing efficiency, and that serious evaluations of modeled OH concentrations be done with air mass weighted [OH]GM broken down into atmospheric sub-compartments, especially focusing on the tropics, where the atmospheric oxidizing efficiency is greatest

    The effects of lightning-produced NO<sub>x</sub> and its vertical distribution on atmospheric chemistry: sensitivity simulations with MATCH-MPIC

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    The impact of different assumptions concerning the source magnitude as well as the vertical placement of lightning-produced nitrogen oxides is studied using the global chemistry transport model MATCH-MPIC. The responses of NO<sub>x</sub>, O<sub>3</sub>, OH, HNO<sub>3</sub> and peroxyacetyl-nitrate (PAN) are investigated. A marked sensitivity to both parameters is found. NO<sub>x</sub> burdens globally can be enhanced by up to 100% depending on the vertical placement and source magnitude strength. In all cases, the largest enhancements occur in the tropical upper troposphere, where lifetimes of most trace gases are longer and where they thus become more susceptible to long-range transport by large-scale circulation patterns. Comparison with observations indicate that 0 and 20 Tg(N)/yr production rates of NO<sub>x</sub> from lightning are too low and too high, respectively. However, no single intermediate production rate or vertical distribution can be singled out as best fitting the observations, due to the large scatter in the datasets. This underscores the need for further measurement campaigns in key regions, such as the tropical continents

    The Role of decision-analytic modelling in German health technology assessments

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    BACKGROUND: Decision-analytic modelling (DAM) has become a widespread method in health technology assessments (HTA), but the extent to which modelling is used differs among international HTA institutions. In Germany, the use of DAM is optional within HTAs of the German Institute of Medical Documentation and Information (DIMDI). Our study examines the use of DAM in DIMDI HTA reports and its effect on the quality of information provided for health policies. METHODS: A review of all DIMDI HTA reports (from 1998 to September 2012) incorporating an economic assessment was performed. All included reports were divided into two groups: HTAs with DAM and HTAs without DAM. In both groups, reports were categorized according to the quality of information provided for healthcare decision making. RESULTS: Of the sample of 107 DIMDI HTA reports, 17 (15.9%) used DAM for economic assessment. In the group without DAM, conclusions were limited by the quality of economic information in 51.1% of the reports, whereas we did not find limited conclusions in the group with DAM. Furthermore, 24 reports without DAM (26.7%) stated that using DAM would likely improve the quality of information of the economic assessment. CONCLUSION: The use of DAM techniques can improve the quality of HTAs in Germany. When, after a systematic review of existing literature within a HTA, it is clear that DAM is likely to positively affect the quality of the economic assessment DAM should be used

    Impact of radiofrequency ablation for patients with varicose veins on the budget of the German statutory health insurance system

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    Objectives: In contrast to other countries, surgery still represents the common invasive treatment for varicose veins in Germany. However, radiofrequency ablation, e.g. ClosureFast, becomes more and more popular in other countries due to potential better results and reduced side effects. This treatment option may cause less follow-up costs and is a more convenient procedure for patients, which could justify an introduction in the statutory benefits catalogue. Therefore, we aim at calculating the budget impact of a general reimbursement of ClosureFast in Germany. Methods: To assess the budget impact of including ClosureFast in the German statutory benefits catalogue, we developed a multi-cohort Markov model and compared the costs of a “World with ClosureFast” with a “World without ClosureFast” over a time horizon of five years. To address the uncertainty of input parameters, we conducted three different types of sensitivity analysis (one-way, scenario, probabilistic). Results: In the Base Case scenario, the introduction of the ClosureFast system for the treatment of varicose veins saves costs of about 19.1 Mio. € over a time horizon of five years in Germany. However, the results scatter in the sensitivity analyses due to limited evidence of some key input parameters. Conclusions: Results of the budget impact analysis indicate that a general reimbursement of ClosureFast has the potential to be cost-saving in the German Statutory Health Insurance

    Age- and gender-based comorbidity categories in general practitioner and pulmonology patients with COPD

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    Chronic obstructive pulmonary disease (COPD) is a debilitating medical condition often accompanied by multiple chronic conditions. COPD is more frequent among older adults and affects both genders. The aim of the current cross-sectional survey was to characterize chronic comorbidities stratified by gender and age among patients with COPD under the care of general practitioners (GP) and pulmonologists, using real-world patient data. A total of 7966 COPD patients (women: 45%) with more than 5 years of the observation period in the practice were examined using 60 different Chronic comorbid conditions (CCC) and Elixhauser measures. More than 9 in 10 patients had at least one, and 51.7% had more than three comorbidities. No gender difference was found in the number of comorbidities. However, men had higher Elixhauser-van Walraven index scores than women, and the types of comorbidities differed by gender. An increasing number of comorbidities was seen with aging but the patients in their 30s and 40s also had a high number of comorbidities. Moreover, GP patients had a higher number and a wider array of documented comorbidities than pulmonology patients did. Psychological comorbidities were common in all patients, but particularly among younger patients. These findings around gender- and age-stratified comorbidities under the care of GPs and pulmonologists have implications for the choice of data provenience for decision-making analysis and treatment selection and success

    a multi-centre cross-country comparison of women in management and leadership in academic health centres in the European Union

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    Background Women’s participation in medicine and the need for gender equality in healthcare are increasingly recognised, yet little attention is paid to leadership and management positions in large publicly funded academic health centres. This study illustrates such a need, taking the case of four large European centres: CharitĂ© – UniversitĂ€tsmedizin Berlin (Germany), Karolinska Institutet (Sweden), Medizinische UniversitĂ€t Wien (Austria), and Oxford Academic Health Science Centre (United Kingdom). Case The percentage of female medical students and doctors in all four countries is now well within the 40–60% gender balance zone. Women are less well represented among specialists and remain significantly under-represented among senior doctors and full professors. All four centres have made progress in closing the gender leadership gap on boards and other top-level decision-making bodies, but a gender leadership gap remains relevant. The level of achieved gender balance varies significantly between the centres and largely mirrors country-specific welfare state models, with more equal gender relations in Sweden than in the other countries. Notably, there are also similar trends across countries and centres: gender inequality is stronger within academic enterprises than within hospital enterprises and stronger in middle management than at the top level. These novel findings reveal fissures in the ‘glass ceiling’ effects at top- level management, while the barriers for women shift to middle-level management and remain strong in academic positions. The uneven shifts in the leadership gap are highly relevant and have policy implications. Conclusion Setting gender balance objectives exclusively for top-level decision-making bodies may not effectively promote a wider goal of gender equality. Academic health centres should pay greater attention to gender equality as an issue of organisational performance and good leadership at all levels of management, with particular attention to academic enterprises and newly created management structures. Developing comprehensive gender-sensitive health workforce monitoring systems and comparing progress across academic health centres in Europe could help to identify the gender leadership gap and utilise health human resources more effectively

    Transport and build-up of tropospheric trace gases during the MINOS campaign: comparision of GOME, in situ aircraft measurements and MATCH-MPIC-data

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    The MINOS (Mediterranean INtensive Oxidant Study) campaign was an international, multi-platform field campaign to measure long-range transport of air-pollution and aerosols from South East Asia and Europe towards the Mediterranean basin during August 2001. High pollution events were observed during this campaign. For the Mediterranean region enhanced tropospheric nitrogen dioxide (NO<sub>2</sub>) and formaldehyde (HCHO), which are precursors of tropospheric ozone (O<sub>3</sub>), were detected by the satellite based GOME (Global Ozone Monitoring Experiment) instrument and compared with airborne in situ measurements as well as with the output from the global 3D photochemistry-transport model MATCH-MPIC (Model of Atmospheric Transport and CHemistry - Max Planck Institute for Chemistry). The increase of pollution in that region leads to severe air quality degradation with regional and global implications

    The Luminosity Function Of Field Galaxies And Its Evolution Since z=1

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    We present the B-band luminosity function and comoving space and luminosity densities for a sample of 2779 I-band selected field galaxies based on multi-color data from the CADIS survey. The sample is complete down to I_815 = 22 without correction and with completeness correction extends to I_815=23.0. By means of a new multi-color analysis the objects are classified according to their spectral energy distributions (SEDs) and their redshifts are determined with typical errors of delta z <= 0.03. We have split our sample into four redshift bins between z=0.1 and z=1.04 and into three SED bins E-Sa,Sa-Sc and starbursting (emission line) galaxies. The evolution of the luminosity function is clearly differential with SED. The normalization phi* of luminosity function for the E-Sa galaxies decreases towards higher redshift, and we find evidence that the comoving galaxy space density decreases with redshift as well. In contrast, we find phi* and the comoving space density increasing with redshift for the Sa-Sc galaxies. For the starburst galaxies we find a steepening of the luminosity function at the faint end and their comoving space density increases with redshift.Comment: 15 pages, 14 figures, accepted by Astronomy&Astrophysic
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