Atom interferometry at geodetic observatories

Das gravimetrische Atominterferometer (GAIN) ist ein transportables Atominterferometer welches spezifisch für hochpräzise Schweremessungen in der Geodäsie und Geophysik entwickelt wurde. Es basiert auf einer Rubidium Atomfontäne, stimulierten Ramanübergängen und einer 3-Puls Mach-Zehnder Interferometriesequenz. Die vorliegende Arbeit beschäftigt sich mit der Optimierung und Anwendung von GAIN als transportables Gravimeter für Absolutschweremessungen an geodätischen Observatorien welche über den aktuellen Stand der Technik hinaus gehen. Dabei wurden eine Absolutgenauigkiet von 29 nm/s^2, eine Langzeitstabilität von 0.4 nm/s^2 sowie eine Sensitivität von 82 nm/s^2 in einer Sekunde erreicht. Die gemessene Genauigkeit und Langzeitstabilität stellen, nach dem Wissen des Authors, die bis heute besten publizierten Werte für ein transportablen Atominterferometer dar und repräsentieren einen bedeutenden Fortschritt im Bereich der Gravimetrie. Um dies zu erreichen wurden umfangreiche Verbesserungen am Gerät umgesetzt und eine ausführliche Analyse der systematischen Messabweichungen durchgeführt. Unter anderem wurden ein System zur Kompensation von Corioliskräften und Ausrichtungsfehlern, ein verbessertes Schwingungsisolationssystem zur nachträglichen Korrektur von Umgebungsvibrationen und eine magnetische Abschirmung instrumenteller Streufelder implementiert. Darüber hinaus wurden insgesamt vier Messkampagnen in Berlin, sowie an den geodätischen Observatorien in Wettzell, Deutschland und Onsala, Schweden durchgeführt, um GAIN mit anderen hochmodernen Absolut- und Relativgravimetern zu vergleichen. Der direkte Vergleich zwischen GAIN und anderen Gravimetern stellt den prinzipbedingten Vorteil der Atominterferometrie durch die Kombination aus Absolutgenauigkeit, Stabilität und Langzeitbetrieb klar hervor. Dies wurde in der Arbeit durch die um einen Faktor 2-5 verbesserte Kalibrierung des Skalenfaktor von zwei supraleitenden Gravimetern demonstriert.The gravimetric atom interferometer (GAIN) is a transportable setup which was specifically designed to perform high-precision gravity measurements at sites of interest for geodesy or geophysics. It is based on a Rb atomic fountain, stimulated Raman transitions and a three-pulse Mach-Zehnder atom interferometry sequence. The presented work is concerned with the optimization and application of GAIN as a transportable gravimeter in order to perform gravity measurements beyond the state-of-the-art. An absolute accuracy of 29 nm/s^2, long-term stability of 0.4 nm/s^2 and short-term noise level as low as 82 nm/s^2 in one second was achieved. The obtained long-term stability and accuracy values are, to the knowledge of the author, the best published performance of any transportable atom interferometer to date and represent a significant advancement in the field of gravimetry. A comprehensive analysis of the systematic error budget was performed to improve the accuracy and stability of the measured gravity value. Several setup improvements were implemented to this end, including Coriolis force and alignment control systems, an improved vibration isolator with post-correction and magnetic shielding which reduces spurious coupling due to stray fields. Measurement campaigns were conducted in Berlin and at geodetic observatories in Wettzell, Germany, and Onsala, Sweden, in order to compare GAIN to other state-of-the-art absolute and relative gravimeters. The direct comparison of GAIN to other absolute and relative gravimeters shows the general advantage of atom interferometers due to their unique combination of absolute accuracy, stability and robust architecture enabling continuous measurements. This was demonstrated during the presented campaigns by the improvement of the scale factor calibration of two superconducting gravimeters by a factor 2 to 5 using GAIN data

Incumbency, Party Identity and Governmental Lead: Evidence for Heterogeneous Incumbency Effects for Germany

Do incumbents in an election have an advantage, and if so, are these advantages heterogeneous across parties or government and opposition? We first present a theoretical discussion on the possible heterogeneity of incumbency effects in a pure two-party system. Then, we estimate the incumbency effect for the direct district candidates in German federal and state elections using a regression discontinuity design (RDD). When studying the heterogeneity in these effects, we find that incumbents from both large parties, the center-right CDU and the center-left SPD, have an advantage only if the SPD is in government. This effect is robust and shows even in state elections that are unrelated to federal elections - calling into question the findings of average incumbency effects in the literature. Because this effect is stronger in the East than in the West and only shows post reunification, we hypothesise that the emergence of the socialist party "The Left" may be behind this heterogeneity.incumbency advantage, regression discontinuity design, federal elections, state elections

The effect of wavefront aberrations in atom interferometry

Wavefront aberrations are one of the largest uncertainty factors in present atom interferometers. We present a detailed numerical and experimental analysis of this effect based on measured aberrations from optical windows. By placing windows into the Raman beam path of our atomic gravimeter, we verify for the first time the induced bias in very good agreement with theory. Our method can be used to reduce the uncertainty in atomic gravimeters by one order of magnitude resulting in an error of less than $3\times 10^{-10}\,g$ and it is suitable in a wide variety of atom interferometers with thermal or ultra cold atoms. We discuss the limitations of our method, potential improvements and its role in future generation experiments.Comment: Applied Physics B, 201

Public Good Provision, Commuting and Local Employment

This paper assesses the differential impact of the local availability of grammar schools on local employment depending on the openness of a jurisdiction, measured by commuting costs. Commuting costs matter as they influence workers' reservation wage. While the reservation wage depends on public good provision in jurisdictions with high commuting costs, it does not so in jurisdictions with low commuting costs as workers' outside option is to commute and not to move away. We test these predictions using local grammar school closures in East Germany after 2000. In line with the predictions we find that school closures reduced employment only in jurisdictions with high commuting costs. Reassuringly, house prices responded, however, similar in both types of jurisdictions which rules out that differences in preferences are driving our results

Using Distributed Ledger Technologies to Support Complex Supply Chains

The concept of blockchain, as part of distributed ledger technologies, has gained a lot of interest recently, especially in cryptocurrencies. With the addition of other technical capabilities, e.g., smart contracts and oracles, this interest has spread to other areas as well and affects a wide variety of business processes such as supply chain processes. However, in research, the wide variety of processes finds inadequate consideration to date. In this research paper, we provide an overview of the state of the art of distributed ledger technologies in supply chains and point out future research topics. Therefore, we conducted a structured literature review, systematized potential application areas in supply chain processes, and showed that research gaps exist. To address the research gaps, we derived open research questions, whereby conducting design studies to deal with the practical problems in the application areas plays a central role

Prescribing and medical non-adherence after myocardial infarction: qualitative interviews with general practitioners in Germany

Background: An increasing prevalence of having survived a myocardial infarction increases the importance of medical secondary prevention. Although preventive medication reduces mortality, prescribing and adherence are known to be frequently insufficient. General practitioners are the most important prescriber. However, their perspective on prescribing and medical non-adherence following myocardial infarction has not yet been explored. Thus, the aim of this study was to explore the general practitioners' perspective on long-term care after myocardial infarction focussing on medical prevention. Methods: In this qualitative interview study we conducted episodic interviews with sixteen general practitioners from rural and urban surgeries in Germany. Framework analysis with focus on general practitioners' prescribing and patients' non-adherence was performed. Results: Almost all general practitioners reported following guidelines for myocardial infarction aftercare and prescribing the medication that was initiated in the hospital; however, they described deviating from guidelines because of drugs' side effects or patients' intolerances. Some questioned the benefits of medical secondary prevention for the oldest of patients. General practitioners perceived good adherence among their patients who had had an MI while they regarded their methods for assessing medical non-adherence as limited. They perceived diverse reasons for non-adherence, particularly side effects, patients' freedom from symptoms and patients' indifference to health. They attributed mainly negative characteristics, like lack of knowledge and understanding, to non-adherent patients. These characteristics contribute to the difficulty of convincing these patients to take medications as prescribed. General practitioners improved adherence by preventing side effects, explaining the medication's necessity, facilitating intake and involving patients in decision-making. However, about half of the general practitioners reported threatening their patients with negative consequences of non-adherence. Conclusions: General practitioners should be aware that discharge medication can be insufficient and thus, should always check hospital recommendations for accordance with guideline recommendations. Improving physicians' communication skills and informing and motivating patients in an adequate manner, for example in simple language, should be an important goal in the hospital and the general practitioner setting. General practitioners should assess patients' motivations through motivational interviewing, which no general practitioner mentioned during the interviews, and talk with them about adherence and long-term treatment goals regularly

Auswertung einer deutschlandweiten Studie zur Anwendung von Pflanzenschutzmitteln in Obstbaubetrieben

Zusammenfassung Im Jahre 2007 wurde das Netz Vergleichsbetriebe Pflanzenschutz etabliert, in das auch Obstbaubetriebe mit Tafelapfelproduktion einbezogen wurden. Ziel einer speziellen Untersuchung war es, die insgesamt 1.645 Pflanzenschutzmittel-Anwendungen in den 15 Vergleichsbetrieben mit Tafelapfelproduktion umfassend zu analysieren. Im Mittelpunkt standen die Analyse der Häufigkeiten und Intensitäten der Pflanzenschutzmittel-Anwendungen (Behandlungsindex), der Reduzierung der Aufwandmengen und der Kosten für den Pflanzenschutz. Die Reduktionspotentiale bei der Anwendung der Pflanzenschutzmittel wurden identifiziert und ökonomisch determiniert. Die Betriebe gaben für die Pflanzenschutzmittel 1.278 €/ha bzw. für die Pflanzenschutzmaßnahmen 1.706 €/ha, d. h. 28 €/ha für Pflanzenschutzmittel pro Maßnahme bzw. 40 €/ha für eine Pflanzenschutzmaßnahme/ha aus. Erstmalig konnten die Kosten für einen Behandlungsindex von 1,0 (53,33 €) im Apfelanbau ermittelt werden. Schließlich wurde untersucht, ob Beziehungen zwischen dem Pflanzenschutzaufwand und den Erträgen bzw. Erlösen bestanden. Dabei wurde die Hypothese widerlegt, dass höhere Aufwendungen für Pflanzenschutz im Zusammenhang mit einem höheren Ertrag stehen. Stichwörter: Pflanzenschutzmittel, Behandlungsindex, Ökonomie, Tafelapfel   Abstract The Plant Protection Reference Farms Network was established in the year 2007. It also includes farms with apple production. The aim of this study was to analyse 1.645 pesticide applications in 15 reference farms with dessert apple production. In particular the frequency and intensity of pesticide uses (Treatment Frequency Index), the use of reduced dosage and the costs of plant protection measures were investigated. The reduction potential in pesticide use was determined and economically calculated. The farms expended 1.278 €/ha for pesticides and 1.706 €/ha for plant protection which corresponded with 28 €/ha for pesticides per one use and 40 €/ha for one treatment. The costs per Treatment Frequency Index = 1.0 (53,33 €) could be calculated for the first time in apple growing. Finally, relationships between pesticide uses on the one hand and yields and profits on the other hand were investigated. The hypothesis that higher pesticide use correlates with higher yields was negated in this study. Keywords: pesticide, treatment index, economy, dessert appl

Dynamic Up-Regulation of PD-L1 in the Progression of Oral Squamous Cell Carcinoma

The introduction of immune checkpoint inhibition for recurrent and metastatic head and neck cancer has brought a new treatment option for patients suffering from advanced oral cancers without a chance for curation using surgery or radiotherapy. The application of immune checkpoint inhibitors in most cases is based on the expression levels of PD-L1 in the tumor tissue. To date, there is a lack of data on the dynamic regulation of PD-L1 during disease progression. Therefore, this study aimed to evaluate the expression levels of PD-L1 in a large cohort of patients (n = 222) with oral squamous cell carcinoma including primary and recurrent tumors. Semiautomatic digital pathology scoring was used for the assessment of PD-L1 expression levels in primary and recurrent oral squamous cell carcinoma. Survival analysis was performed to evaluate the prognostic significance of the protein expression at different stages of the disease. We found a significant up-regulation of PD-L1 expression from primary disease to recurrent tumors (mean PD-L1 H-scores: primary tumors: 47.1 ± 31.4; recurrent tumors: 103.5 ± 62.8, p < 0.001). In several cases, a shift from low PD-L1 expression in primary tumors to high PD-L1 expression in recurrent tumors was identified. Multivariate Cox regression analysis did not reveal a significantly higher risk of death (p = 0.078) or recurrence (p = 0.926) in patients with higher PD-L1 expression. Our findings indicate that the exclusive analysis of primary tumor tissue prior to the application of checkpoint blockade may lead to the misjudgment of PD-L1 expression in recurrent tumors

Free-Flap Reconstruction in Early-Stage Squamous Cell Carcinoma of the Oral Cavity : A Prospective Monocentric Trial to Evaluate Oncological Outcome and Quality of Life

Surgery is generally accepted as standard treatment in oral cancer, but the reconstructive procedures remain a matter of debate. The aim of this study was to evaluate oncological outcome and quality of life following surgical resection and free-flap reconstruction in patients with early oral squamous cell carcinoma. The presented trial was performed as a prospective, single-center observation study. Inclusion criteria were primary surgery in early-stage oral squamous cell carcinoma with free-flap reconstruction. Endpoints were overall and progression-free survival and quality of life up to 24 months after surgery. Twenty-six patients were included. Overall survival was 100% and progression-free survival was 92.3% in a maximum follow-up time of 21 months. Global quality of life showed no significant alteration after surgery. Patients reported a significant reduction in pain (p = 0.048) and a decreasing impairment of speech one year after surgery (p = 0.021). Free-flap reconstruction is a safe procedure that results in excellent oncological outcome and quality of life. Functional outcome is of high relevance in early-stage tumors of the head and neck and may mostly be affected by reconstructive procedures. Therefore, a prospective evaluation to explore success and the effects of surgical therapy is highly warranted

Mobile quantum gravity sensor with unprecedented stability

Changes of surface gravity on Earth are of great interest in geodesy, earth sciences and natural resource exploration. They are indicative of Earth system's mass redistributions and vertical surface motion, and are usually measured with falling corner-cube- and superconducting gravimeters (FCCG and SCG). Here we report on absolute gravity measurements with a mobile quantum gravimeter based on atom interferometry. The measurements were conducted in Germany and Sweden over periods of several days with simultaneous SCG and FCCG comparisons. They show the best-reported performance of mobile atomic gravimeters to date with an accuracy of 39 nm/s^2, long-term stability of 0,5 nm/s^2 and short-term noise of 96 nm/s^2/(Hz)^1/2. These measurements highlight the unique properties of atomic sensors. The achieved level of performance in a transportable instrument enables new applications in geodesy and related Fields, such as continuous absolute gravity monitoring with a single instrument under rough environmental conditions