Vertical structures induced by embedded moonlets in Saturn's rings: the gap region

We study the vertical extent of propeller structures in Saturn's rings. Our focus lies on the gap region of the propeller and on non-inclined propeller moonlets. In order to describe the vertical structure of propellers we extend the model of Spahn and Sremcevic (2000) to include the vertical direction. We find that the gravitational interaction of ring particles with the non-inclined moonlet does not induce considerable vertical excursions of ring particles, but causes a considerable thermal motion in the ring plane. We expect ring particle collisions to partly convert the lateral induced thermal motion into vertical excursions of ring particles. For the gap region of the propeller, we calculate gap averaged propeller heights on the order of 0.7 Hill radii, which is of the order of the moonlet radius. In our model the propeller height decreases exponentially until viscous heating and collisional cooling balance. We estimate Hill radii of 370m and 615m for the propellers Earhart and Bleriot. Our model predicts about 120km for the azimuthal extent of the Earhart propeller at Saturn's 2009 equinox, being consistent with values determined from Cassini images

Rotational and high-resolution infrared spectrum of HC3_3N: global ro-vibrational analysis and improved line catalogue for astrophysical observations

HC$_3$N is an ubiquitous molecule in interstellar environments, from external galaxies, to Galactic interstellar clouds, star forming regions, and planetary atmospheres. Observations of its rotational and vibrational transitions provide important information on the physical and chemical structure of the above environments. We present the most complete global analysis of the spectroscopic data of HC$_3$N. We have recorded the high-resolution infrared spectrum from 450 to 1350 cm$^{-1}$, a region dominated by the intense $\nu_5$ and $\nu_6$ fundamental bands, located at 660 and 500 cm$^{-1}$, respectively, and their associated hot bands. Pure rotational transitions in the ground and vibrationally excited states have been recorded in the millimetre and sub-millimetre regions in order to extend the frequency range so far considered in previous investigations. All the transitions from the literature and from this work involving energy levels lower than 1000 cm$^{-1}$ have been fitted together to an effective Hamiltonian. Because of the presence of various anharmonic resonances, the Hamiltonian includes a number of interaction constants, in addition to the conventional rotational and vibrational l-type resonance terms. The data set contains about 3400 ro-vibrational lines of 13 bands and some 1500 pure rotational lines belonging to 12 vibrational states. More than 120 spectroscopic constants have been determined directly from the fit, without any assumption deduced from theoretical calculations or comparisons with similar molecules. An extensive list of highly accurate rest frequencies has been produced to assist astronomical searches and data interpretation. These improved data, have enabled a refined analysis of the ALMA observations towards Sgr B2(N2).Comment: 35 pages, 14 figures, accepted for pubblication in ApJ Supplemen

Predicting Survival for Veno-Arterial ECMO Using Conditional Inference Trees-A Multicenter Study

BACKGROUND Despite increasing use and understanding of the process, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy is still associated with considerable mortality. Personalized and quick survival predictions using machine learning methods can assist in clinical decision making before ECMO insertion. METHODS This is a multicenter study to develop and validate an easy-to-use prognostic model to predict in-hospital mortality of VA-ECMO therapy, using unbiased recursive partitioning with conditional inference trees. We compared two sets with different numbers of variables (small and comprehensive), all of which were available just before ECMO initiation. The area under the curve (AUC), the cross-validated Brier score, and the error rate were applied to assess model performance. Data were collected retrospectively between 2007 and 2019. RESULTS 837 patients were eligible for this study; 679 patients in the derivation cohort (median (IQR) age 60 (49 to 69) years; 187 (28%) female patients) and a total of 158 patients in two external validation cohorts (median (IQR) age 57 (49 to 65) and 70 (63 to 76) years). For the small data set, the model showed a cross-validated error rate of 35.79% and an AUC of 0.70 (95% confidence interval from 0.66 to 0.74). In the comprehensive data set, the error rate was the same with a value of 35.35%, with an AUC of 0.71 (95% confidence interval from 0.67 to 0.75). The mean Brier scores of the two models were 0.210 (small data set) and 0.211 (comprehensive data set). External validation showed an error rate of 43% and AUC of 0.60 (95% confidence interval from 0.52 to 0.69) using the small tree and an error rate of 35% with an AUC of 0.63 (95% confidence interval from 0.54 to 0.72) using the comprehensive tree. There were large differences between the two validation sets. CONCLUSIONS Conditional inference trees are able to augment prognostic clinical decision making for patients undergoing ECMO treatment. They may provide a degree of accuracy in mortality prediction and prognostic stratification using readily available variables

Near-infrared (NIR) spectroscopy. A new method for arthroscopic evaluation of low grade degenerated cartilage lesions. Results of a pilot study

<p>Abstract</p> <p>Background</p> <p>Arthroscopy is a highly sensitive method of evaluating high-grade cartilage lesions but the detection of low-grade lesions is often is unreliable. Objective measurements are required. A novel NIRS (near-infrared-spectroscopy) device for detection of low-grade cartilage defects was evaluated in a preliminary clinical study.</p> <p>Methods</p> <p>In 12 patients who had undergone arthroscopy, the cartilage lesions within the medial knee compartment were classified according to the ICRS protocol.</p> <p>With a NIR spectrometer system and an optical probe, similar in design to a hook used for routine arthroscopy, the optical properties of cartilage were measured during arthroscopy.</p> <p>Results</p> <p>The mean ratio of 2 NIR absorption bands of intact cartilage 3.8 (range 2.3 to 8.7).was significantly lower than that of cartilage with grade 1 lesions (12.8, range 4.8 to 19.6) and grade 2 lesions (13.4, range 10.4 to 15.4).</p> <p>No differences were observed between grade 1 and grade 2 lesions.</p> <p>Conclusion</p> <p>NIRS can be used to distinguish between ICRS grade 1 lesions and healthy cartilage during arthroscopic surgeries. The results of this clinical study demonstrate the potential of NIRS to objectify classical arthroscopic grading systems.</p

Untersuchungen der Verhältnisse stabiler Kohlenstoffisotope in atmosphärisch relevanten VOC in Simulations- und Feldexperimenten

Flüchtige organische Verbindungen (VOC) spielen eine wichtige Rolle in der regionalen und globalen Chemie der Atmosphäre. In stark belasteten Gebieten können VOC nicht nur in gesundheitsschädlichen Konzentrationen auftreten, sondern auch bei der Oxidation in Anwesenheit hoher Stickoxid- Konzentrationen Ozon erzeugen, das für den Menschen und seine Umwelt giftig ist. Neben ihrem unmittelbaren Einfluss auf den menschlichen Organismus beeinflussen VOC auch global die Umwelt des Menschen. Durch ihre atmosphärische Oxidation können VOC in eine fast unüberschaubare Zahl anderer Spurengase umgewandelt werden, am Ende auch in klimaschädliche Treibhausgase wie CO$_{2}$. Hinzu kommt, dass VOC den Aerosol-Haushalt der Erde mitbeeinflussen. Sie können zum einen selbst Partikel bilden, zum anderen aber auch die chemischen und physikalischen Eigenschaften bereits bestehender Aerosole beeinflussen. Dadurch haben sie sowohl Einfluss auf die Bildung von Regentropfen als auch auf den Strahlungshaushalt der Erde. Wegen dieser umfassenden Bedeutung ist es wichtig, die Eigenschaften von VOC und deren chemische Prozesse in der Atmosphäre zu verstehen, um so besser deren zukünftige Entwicklung vorhersagen zu können. Diese Arbeit beschäftigt sich mit der Analyse der Verhältnisse stabiler Kohlenstoffisotope ($\delta(^{13}$C)-Analyse) in atmosphärischen VOC. Die $\delta(^{13}$C)-Analyse erlaubt es, durch die Charaktersierung von Emissionsquellen und die Bestimmung des kinetischen Isotopeneffekts (KIE) verschiedener chemischer Reaktionen sowohl den Transport als auch die chemischen Einflüsse von VOC in der Erdatmosphäre besser zu verstehen. Da die $\delta(^{13}$C)-Analyse in der Atmosphärenforschung bisher nur wenig verbreitet ist, gibt diese Arbeit auch einen kurzen Überblick über den momentanen Stand der Technik. In dieser Arbeit wurden $\delta(^{13}$C)-Analysen ausgewählter VOC in Labor- und Feldmessungen vorgenommen. Bei der Untersuchung pflanzlicher Emission an einer Pflanzenkammer wurden erstmals die $\delta(^{13}$C)-Werte verschiedener Monoterpene bestimmt ($\alpha$-Pinen, $\beta$-Pinen, trans-$\beta$-Ocimen, Limonen und [...