Zur Variabilität der Dynamik in der Stratosphäre : eine Untersuchung auf Grundlage der Varianz von chemischen Tracern

In der Stratosphäre finden eine Reihe von dynamischen und chemischen Prozessen statt, die u.a. den Abbau von Ozon beeinflussen. Um die langfristigen Veränderungen in der Stratosphäre untersuchen zu können müssen die Abhängigkeit dieser Prozesse von Raum und Zeit bekannt sein. In dieser Arbeit wird eine Untersuchung zur Variabilität der Stratosphäre auf der Grundlage der Varianz von Tracern, die in Form der „Equivalent Displacement Height“, kurz: EDH, dargestellt wird, vorgestellt. Die EDH ist tue mit Hilfe des lokalen vertikalen Gradienten normierte lokale Standardabweichung des Mischungsverhältnisses eines Tracers und besitzt die Dimension einer Länge. Durch die Normierung kann die Varianz verschiedener Tracer miteinander verglichen werden. Mit dem Konzept ist allerdings nur die Diagnose der Variabilität möglich und keine Quantifizierung der dafür verantwortlichen Prozesse. Für die Fragestellung werden drei Datensätze ausgewertet. Ein Datensatz ist mit Hilfe eines kryogenen Luftprobensammlers entstanden. Die Berechnungen iii dieser Arbeit zeigen, dass die zeitliche und räumliche Abdeckung dieses Datensatzes zu niedrig ist, um mit ihm eine repräsentative Aussage über die Varianz von Spurengasen in der Stratosphäre treffen zu können. Eine bessere zeitliche und räumliche Abdeckung besitzt der Datensatz des Satellitenexperimentes HA-LOE. Dieser wird dazu verwendet die monatlichen Verteilungen der mittleren EDH von CH4 und O3 in einem Höhenbereich zwischen 19 und 50 km für einen Zeitraum von 1993 bis 2000 zu berechnen. Die mittlere EDH von OH4 besitzt über den Hemisphären jeweils einen unterschiedlichen Jahresgang. Die Diskussion zeigt, dass dieser hemisphärische Unterschied auf die verschiedenen dynamischen Bedingung in der Stratosphäre über den Hemisphären zurückgeführt werden kann, vor allem auf die Existenz eines stabileren und langlebigeren Polarwirbels in der Südhemisphäre. Im Gegensatz dazu zeigt die mittlere EDH von O3 über beiden Hemisphären einen vergleichbaren Jahresgang, mit minimalen Werten der Varianz während der Sommermonate, wenn die Ausbreitung planetarer Wellen in die Stratosphäre durch die vorherrschende Ostwindzirkulation behindert wird. Dieser Jahresgang steht in Verbindung mit den chemischen und dynamischen Prozessen bzw. der Kombination, welche die Verteilung und Varianz von O3 in der Stratosphäre kontrollieren. Eine eindeutige Trennung der einzelnen Effekte ist dabei allerdings nicht möglich. Der Datensatz des Simulationsmodell KASIMA enthält die Verteilung von CH4 und O3 mit der höchsten zeitlichen und räumliche Abdeckung aller drei Datensätze. Ein Vergleich zwischen den daraus berechneten Verteilungen der mittleren EDH beider Spurengase mit den HALOE-Daten soll helfen, die Varianz welche durch das Modell simuliert wird, mit der gemessenen zu vergleichen. Für das O3 wird eine gute Übereinstimmung zwischen der modellierten und gemessenen Varianz gefunden. Diese guten Übereinstimmungen ergeben sich für CH4 nicht. Aufgrund der unterschiedlichen chemischen Eigenschaften der beiden Tracer wird aus den Ergebnissen geschlossen, dass das Modell die chemischen Prozesse besser simuliert als den atmosphärischen Transport. Mit Hilfe von drei Fallstudien werden weitere Möglichkeiten aufgezeigt. die mit dem Konzept und den Datensätze von HALOE und KASIMA noch bestehen. In der ersten Fallstudie werden anhand der Verteilungen der EDH von CH4 aus dem März 1996 und 1997 die Auswirkungen vorm zwei unterschiedlichen meteorologischen Situation diskutiert, wobei ein eindeutiger Zusammenhang festgestellt wird. In einer zweiten Fallstudie wird der Frage nachgegangen, ob die Normierung auf den vertikalen Gradienten bei der Berechnung der EDH sinnvoll ist, da horizontale Transportprozesse in der Stratosphäre dominieren. Es wird daher zum Vergleich die „Equivalent Displacement Length (EDL)“ von CH4 berechnet, bei der eine Normierung der Varianz auf den horizontalen Gradienten erfolgt. In der dritten Fallstudie wird die Verteilung der mittleren EDH von N20, welche ebenfalls mit dem Datensatz von KASIMA berechnet worden ist, mit der von CH4 verglichen

Investigation towards an active barrier for structure borne sound using structural intensity

Vibrations of aircraft or vehicle engines, for instance, are often transmitted by structure borne sound, leading to a significant radiation of noise inside passenger cabins. Current active vibration control concepts use either velocity or acceleration as a control source. However, these only lead to a local reduction in vibration and not necessarily to the reduction of the vibration energy flow. This study presents the implementation of current methods for structural intensity measurement with a real-time control. The work investigates one and two-dimensional structures. A reduction of energy flow in a beam structure is shown experimentally, as well as numerically for plates. The measurements are strongly influenced by theoretical simplifications concerning the composition of the structure borne waves and the quality of the sensor arrays used, i.e. the sensor spacing and the positioning accuracy. Though, sufficient accordance between numerically and experimentally estimated structural intensity can be found using methods with smaller sensor arrays. A barrier effect is shown by numerical investigations and is measured on a beam. Therefore, the control of vibration energy flow is a more effective method for a global reduction if vibration downstream the control area

Transmission loss variation of mass constant sandwich plates using geometric honeycomb core variation

Pollutant emissions like CO2 or NOX increased in the last decades. One reason is the increased av-erage distance covered by each person which has grown in a similar proportion. This again leads to the use of vehicles with combustion process more frequently. In order to counteract this trend, the government restricts the pollutant emission of new vehicles. One approach for efficient vehicles is the reduction of the transported mass. Lightweight structures such as sandwich composites offer the possibility of mass reduction with similar stiffness. Unfortunately, this leads to an increased sound radiation at lower frequencies. Therefore, insulating elements are necessary to reduce the sound transmission in the vehicle cabin, but this increases the mass and counteract the benefit of the light-weight structures. The example of sandwich plates will be used to show that the geometrical variation of a honeycomb core can increase the transmission loss. The core mass stays constant during this variation. The cell diameter of these cores varies between 5 cm and 13 cm, while commercially available cores have often diameters in millimeter range. The core variation is done with finite element analysis in the frequency range up to 2000 Hz. The transmission loss of selected sandwich plates is measured in order to confirm the simulation results. If the cell diameter size increases, the transmission loss in-crease can be shifted to lower frequencies. With a cell diameter of 13 cm the averaged increase of the transmission loss is by 3 dB and it starts by approximately 500 Hz. Thus, the design of a mass constant core improves the acoustic properties of a sandwich and it can address critical frequencies. Such acoustically adapted lightweight structures will reduce the number of insulating elements in vehicles. This design approach can contribute to lower the pollutant emissions of future vehicles

Evaluation of grain legume cropping systems for animal fodder potential and impacts on subsequent wheat yield under less favourable soil conditions in organic agriculture in Luxembourg

Körnerleguminosen sind wichtige Kulturen für die Bereit­stellung von Protein in der Tierernährung. Ziel dieser Studie war es: (i) die Eignung verschiedener Körnerleguminosen-Anbausysteme für den Anbau als proteinreiches Futtermittel zu prüfen, (ii) der Vergleich von Sommer- und Winterform von Ackerbohnen und Erbsen, sowie der Erbse in Reinsaat und im Gemenge mit Getreide, und (iii) der Vergleich des Einflusses der Leguminosen als Vorfrüchte auf den nachfolgenden Weizen unter ungünstigen Bodenbedingungen im ökologischen Landbau. In einem Feldversuch auf einem kommerziellen landwirtschaftlichen Betrieb in Luxemburg, wurden acht Körnerleguminosen-Anbausysteme (wie in ii beschrieben plus Sojabohne und Blaue Lupine) und eine nicht Stickstoff fixierende Kontroll-Kultur (Triticale) in zwei aufeinanderfolgenden Jahren, in einem vollständig randomisierten Blockdesign mit vier Wiederholungen, angebaut. Als Folgekultur wurde Weizen angebaut. Alle Anbausysteme, mit Ausnahme der Winter-Erbse in Reinsaat, waren für den Anbau als proteinreiches Futtermittel geeignet. Bei ausreichender Bodenfeuchte stellte die Ackerbohne die beste Wahl dar (Proteinertrag: 961–1193 kg ha–1). Halbblattlose Erbsen erzielten einen signifikant höheren Ertrag in Reinsaat (p ≤ 0.05; 3539–4154 kg ha–1) als im Gemenge mit Getreide (2920–3852 kg ha–1), wobei Voll­blatt-Typen im Gemenge mit Getreide angebaut werden sollten. Es wurden keine signifikante Unterschiede festgestellt zwischen Winter- und Sommer-Ackerbohnen, dage­gen schnitt die Sommerung bei den Erbsen besser ab, dies war wahrscheinlich eher abhängig vom Blatt-Typ als vom Saatzeitpunkt. Der niedrigere Vorfruchtwert von Getreide-Monokultur (Ertrag Jahr 1: 2056 kg ha–1) im Vergleich zu Getreide mit Körnerleguminosen in der Fruchtfolge wurde bestätigt, wobei der Weizen am besten nach Sommer-Erbse in Reinsaat abschnitt (Ertrag Jahr 1: 3661 kg ha–1). Körnerleguminosen-Reinsaaten erzielten einen höheren Vorfruchtwert, als Winter-Triticale oder Körnerleguminosen im Gemenge mit Getreide. Körner­leguminosen sind demnach vielversprechende Kulturen für die Bereitstellung proteinreicher Futtermittel auch unter ungünstigen Bodenbedingungen im ökologischen Landbau in Luxemburg. DOI: 10.5073/JfK.2016.06.02, https://doi.org/10.5073/JfK.2016.06.02Grain legumes are important crops required for protein-rich animal fodder. The aim of this study was to (i) examine the suitability of grain legume cropping systems for cultivation as protein-rich fodder, (ii) compare the performance of winter and spring types of faba beans and peas, as well as to compare the performance of peas sown in pure stand and in mixture with cereals, and (iii) determine the impact of previous legume crop on succeeding wheat under less favorable soil conditions in organic agriculture. In a field trial on a commercial farm in Luxembourg, eight grain legume cropping systems (as given under ii plus soybean and blue lupin) and a non-nitrogen fixing control crop (triticale) were cultivated followed by wheat in two consecutive seasons, employing a randomized complete block design with four replicates. All cropping systems except for winter pea in pure stand, were suitable for cultivation as protein-rich fodder even under less favourable soil conditions. Given sufficient soil moisture, faba beans constituted the best choice (protein yield: 961–1193 kg ha–1). Semi-leafless peas reached a significantly better yield when sown in pure stand (p ≤ 0.05; 3539–4154 kg ha–1) compared with the mixture (2920–3852 kg ha–1), whereas full-leaf types should be cultivated with a cereal partner. Winter vs. spring faba beans did not perform significantly different while for peas, the spring form performed best, likely again depending on leaf type rather than sowing time. The lower previous crop value of mono-cropped cereals (yield first experimental sequence: 2056 kg ha–1) compared with cereals in mixture with grain legumes was confirmed, with best performance of wheat succeeding spring pea in pure stand (first experimental sequence, yield: 3661 kg ha–1). Grain legumes in pure stand exhibited a higher previous crop value than winter triticale or grain legumes grown in mixture. In conclusion, grain legumes were promising candidates for generating protein-rich feedingstuffs, even under less favorable soil conditions in organic agriculture in Luxembourg. DOI: 10.5073/JfK.2016.06.02, https://doi.org/10.5073/JfK.2016.06.0

Impact of the contacting scheme on I-V measurements of metallization-free silicon heterojunction solar cells

I-V measurements are sensitive to the number and positioning of current and voltage sensing contacts. For busbarless solar cells, measurement setups have been developed using current collection wires and separate voltage sense contacts. Placing the latter at a defined position enables a grid resistance neglecting measurement and thus I-V characteristics independent from the contacting system. This technique has been developed for solar cells having a finger grid and good conductivity in the direction of the fingers. The optimal position of the sense contact in case of finger-free silicon heterojunction solar cells has not yet been studied. Here, the lateral charge carrier transport occurs in a transparent conductive oxide layer resulting in a higher lateral resistance. We perform finite difference method simulations of HJT solar cells without front metallization to investigate the impact of high lateral resistances on the I-V measurement of solar cells. We show the high sensitivity on the number of used wires for contacting as well as the position of the sense contact for the voltage measurement. Using the simulations, we are able to explain the high difference of up to 7.5% in fill factor measurements of metal free solar cells with varying TCO sheet resistances between two measurement systems using different contacting setups. We propose a method to compensate for the contacting system to achieve a grid-resistance neglecting measurement with both systems allowing a reduction of the FF difference to below 1.5%

Long-term validation of ESA operational retrieval (version 6.0) of MIPAS Envisat vertical profiles of methane, nitrous oxide, CFC11, and CFC12 using balloon-borne observations and trajectory matching

MIPAS-Envisat is a satellite-borne sensor which measured vertical profiles of a wide range of trace gases from 2002 to 2012 using IR emission spectroscopy. We present geophysical validation of the MIPAS-Envisat operational retrieval (version 6.0) of N$_{2}$O, CH$_{4}$, CFC-12, and CFC-11 by the European Space Agency (ESA). The geophysical validation data are derived from measurements of samples collected by a cryogenic whole air sampler flown to altitudes of up to 34 km by means of large scientific balloons. In order to increase the number of coincidences between the satellite and the balloon observations, we applied a trajectory matching technique. The results are presented for different time periods due to a change in the spectroscopic resolution of MIPAS in early 2005. Retrieval results for N$_{2}$O, CH$_{4}$, and CFC-12 show partly good agreement for some altitude regions, which differs for the periods with different spectroscopic resolution. The more recent low spectroscopic resolution data above 20 km altitude show agreement with the combined uncertainties, while there is a tendency of the earlier high spectral resolution data set to underestimate these species above 25 km. The earlier high spectral resolution data show a significant overestimation of the mixing ratios for N$_{2}$O, CH$_{4}$, and CFC-12 below 20 km. These differences need to be considered when using these data. The CFC-11 results from the operation retrieval version 6.0 cannot be recommended for scientific studies due to a systematic overestimation of the CFC-11 mixing ratios at all altitudes

Система поддержки принятие решений при проведении клинических исследований

Разработка программного обеспечения для проведения клинических исследований. Данное приложение может применяться для обеспечения целостности данных, безопасности субъекта исследования, качества продукта в ходе проведения исследования, что приведет к автоматизации рутинных процессов и будет способствовать повышению скорости и качества проводимых исследований.Development of software for conducting clinical trials. This application can be used to ensure data integrity, security of the research subject, and product quality during the research, which will lead to automation of routine processes and will help to improve the speed and quality of research

German evidence and consensus‐based (S3) guideline: Vaccination recommendations for the prevention of HPV‐associated lesions

Anogenital and oropharyngeal infections with human papilloma viruses (HPV) are common. Clinically manifest disease may significantly impact quality of life; the treatment of HPV-associated lesions is associated with a high rate of recurrence and invasive neoplasms, such as cervical, anal, vulvar, penile, and oropharyngeal cancers, which are characterized by significant morbidity and mortality. Vaccination against HPV is an effective and safe measure for the primary prevention of HPV-associated lesions, but immunization rates are still low in Germany. The present publication is an abridged version of the German evidence and consensus-based guideline "Vaccination recommendations for the prevention of HPV-associated lesions", which is available on the website of the German Association of the Scientific Medical Societies (AWMF). On the basis of a systematic review with meta-analyses, a representative panel developed and agreed upon recommendations for the vaccination of different populations against HPV. In addition, consensus-based recommendations were developed for specific issues relevant to everyday practice. Based on current evidence and a representative expert consensus, these recommendations are intended to provide guidance in a field in which there is often uncertainty and in which both patients and health care providers are sometimes confronted with controversial and emotionally charged points of view

Diagnosis of obstructive coronary artery disease using computed tomography angiography in patients with stable chest pain depending on clinical probability and in clinically important subgroups: meta-analysis of individual patient data

OBJECTIVE: To determine whether coronary computed tomography angiography (CTA) should be performed in patients with any clinical probability of coronary artery disease (CAD), and whether the diagnostic performance differs between subgroups of patients. DESIGN: Prospectively designed meta-analysis of individual patient data from prospective diagnostic accuracy studies. DATA SOURCES: Medline, Embase, and Web of Science for published studies. Unpublished studies were identified via direct contact with participating investigators. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Prospective diagnostic accuracy studies that compared coronary CTA with coronary angiography as the reference standard, using at least a 50% diameter reduction as a cutoff value for obstructive CAD. All patients needed to have a clinical indication for coronary angiography due to suspected CAD, and both tests had to be performed in all patients. Results had to be provided using 2×2 or 3×2 cross tabulations for the comparison of CTA with coronary angiography. Primary outcomes were the positive and negative predictive values of CTA as a function of clinical pretest probability of obstructive CAD, analysed by a generalised linear mixed model; calculations were performed including and excluding non-diagnostic CTA results. The no-treat/treat threshold model was used to determine the range of appropriate pretest probabilities for CTA. The threshold model was based on obtained post-test probabilities of less than 15% in case of negative CTA and above 50% in case of positive CTA. Sex, angina pectoris type, age, and number of computed tomography detector rows were used as clinical variables to analyse the diagnostic performance in relevant subgroups. RESULTS: Individual patient data from 5332 patients from 65 prospective diagnostic accuracy studies were retrieved. For a pretest probability range of 7-67%, the treat threshold of more than 50% and the no-treat threshold of less than 15% post-test probability were obtained using CTA. At a pretest probability of 7%, the positive predictive value of CTA was 50.9% (95% confidence interval 43.3% to 57.7%) and the negative predictive value of CTA was 97.8% (96.4% to 98.7%); corresponding values at a pretest probability of 67% were 82.7% (78.3% to 86.2%) and 85.0% (80.2% to 88.9%), respectively. The overall sensitivity of CTA was 95.2% (92.6% to 96.9%) and the specificity was 79.2% (74.9% to 82.9%). CTA using more than 64 detector rows was associated with a higher empirical sensitivity than CTA using up to 64 rows (93.4% v 86.5%, P=0.002) and specificity (84.4% v 72.6%, P<0.001). The area under the receiver-operating-characteristic curve for CTA was 0.897 (0.889 to 0.906), and the diagnostic performance of CTA was slightly lower in women than in with men (area under the curve 0.874 (0.858 to 0.890) v 0.907 (0.897 to 0.916), P<0.001). The diagnostic performance of CTA was slightly lower in patients older than 75 (0.864 (0.834 to 0.894), P=0.018 v all other age groups) and was not significantly influenced by angina pectoris type (typical angina 0.895 (0.873 to 0.917), atypical angina 0.898 (0.884 to 0.913), non-anginal chest pain 0.884 (0.870 to 0.899), other chest discomfort 0.915 (0.897 to 0.934)). CONCLUSIONS: In a no-treat/treat threshold model, the diagnosis of obstructive CAD using coronary CTA in patients with stable chest pain was most accurate when the clinical pretest probability was between 7% and 67%. Performance of CTA was not influenced by the angina pectoris type and was slightly higher in men and lower in older patients. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42012002780