941 research outputs found
Inbetriebnahme und Leistungstest des Fokalreduktors MOSCA fĂŒr das 3,5--Meter--Teleskop auf dem Calar Alto
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 AbbildungsmaĂstab werden bestimmt. Der MaĂstab von durchschnittlich ( 21,572 bogeneskunden/mm ) Ă€ndert sich ĂŒber das 11,4 bogenminutenmin * 11,4 bogenminuten groĂe 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 vergröĂert sich infolge von Bildfehlern von der Mitte bis zum Rand des Bildfeldes um 0,17 bogensekunden. Wegen des grossen ĂffnungsverhĂ€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
The concept of âstructural stabilityâ has been gaining prominence in development policy circles. In the EUâs and the OECD Development Assistance Committeeâs (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 âdemocracyâ and ârule of law,â respectively, on the one hand and the dependent variable âviolence/ human securityâ 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?
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
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
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
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 âWorld with ClosureFastâ with a âWorld without ClosureFastâ 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 19.1âMio. ⏠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
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
Background Womenâs 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© â UniversitĂ€tsmedizin Berlin (Germany), Karolinska
Institutet (Sweden), Medizinische UniversitÀt 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
40â60% 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 âglass ceilingâ 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
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
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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