A Method for Retrieving Stratospheric Aerosol Extinction and Particle Size from Ground-Based Rayleigh-Mie-Raman Lidar Observations

We report on the retrieval of stratospheric aerosol particle size and extinction coefficient profiles from multi-color backscatter measurements with the Rayleigh-Mie-Raman lidar operated at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) in northern Norway. The retrievals are based on a two-step approach. In a first step, the median radius of an assumed monomodal log-normal particle size distribution with fixed width is retrieved based on a color index formed from the measured backscatter ratios at the wavelengths of 1064nm and 532 nm. An intrinsic ambiguity of the retrieved aerosol size information is discussed. In a second step, this particle size information is used to convert the measured lidar backscatter ratio to aerosol extinction coefficients. The retrieval is currently based on monthly-averaged lidar measurements and the results for March 2013 are discussed. A sensitivity study is presented that allows for establishing an error budget for the aerosol retrievals. Assuming a monomodal log-normal aerosol particle size distribution with a geometric width of S = 1.5, median radii on the order of below 100 nm are retrieved. The median radii are found to generally decrease with increasing altitude. The retrieved aerosol extinction profiles are compared to observations with the OSIRIS (Optical Spectrograph and InfraRed Imager System) and the OMPS-LP (Ozone Mapping Profiling Suite Limb Profiler) satellite instruments in the 60° N to 80° N latitude band. The extinction profiles that were retrieved from the lidar measurements show good agreement with the observations of the two satellite instruments when taking the different wavelengths of the instruments into account. © 2020 by the authors

Guidance on Versioning of Digital Assets

Versioning of data and metadata is a crucial - but often overlooked - topic in scientific work. Using the wrong version of a (meta)data set can lead to drastically difference outcomes in interpretation, and lead to substantial, propagating downstream errors. At the same time, past versions of (meta)data sets are valuable records of the research process which should be preserved for transparency and complete reproducibility. Further, the final version of (meta)data sets may actually include errors that previous versions did not. Thus, careful version control is the foundation for trust in and broad reusability of research and operational (meta)data. This document provides an introduction to the principles of versioning, technical recommendations on how to manage version histories, and discusses some pitfalls and possible solutions. In the first part of this document, we present examples of change processes that require proper management and introduce popular versioning schemes. Finally, the document presents recommended practices for researchers as well as for infrastructure developers

An Education Broker Toolset for Web Course Customization

Within an Electronic Education Market an Electronic Education Mall is defined as a virtual service center to support various transaction processes by providing a technological platform with appropriate value-added services and interfaces for suppliers and customers. In this context, an Education Broker service is of central importance because the quality of the learning process is strongly determined by the quality of the available materials and their configuration to an integrated course according to a pedagogical concept and the respective customers' needs. To support these tasks an Education Broker toolset is introduced which allows to select the 'right' elements out of a set of generally suitable learning modules, to adjust and structure the chosen learning modules to an integrated course in a pedagogically and didactically useful way, to add navigational guides, to provide added values and to deliver the integrated course to allow an intuitive application by the student

Learner support in a distributed learning environment:the use of WWW-based teachware packages

Various forms of education and training, based on the classical Computer Based Training (CBT), have become well established within companies and in higher education. With regard to the flexibility in terms of time and location, as well as in terms of incurred cost, they are far superior to traditional forms of instruction. A relatively recent development which has not yet gained widespread acceptance is the use of the World Wide Web (WWW) as a basis and platform for distributed computer assisted teaching and learning. In addition to the advantages outlined with regard to classical CBT, the WWW offers the two advantages of world wide availablity as well as ease of promptly updating courses, but also adds many possibilities of collaborative learning. Using the Java programming language and the ever improving means of online presentation it has become possible to realize sophisticated WWW-based teachware packages which are comparable in terms of appearance and functionality to classical CBT applications created with dedicated authoring systems

CT-guided biopsies of unspecified suspect intrahepatic lesions: pre-procedure Lipiodol-marking improves the biopsy success rate

While computed tomography (CT)-guided liver biopsies are commonly performed using unenhanced images, contrast-enhanced images are beneficial for challenging puncture pathways and lesion locations. This study aimed to evaluate the accuracy of CT-guided biopsies for intrahepatic lesions using unenhanced, intravenous (IV)-enhanced, or intra-arterial Lipiodol-marked CT for lesion marking

Evaluation of two different transarterial chemoembolization protocols using Lipiodol and degradable starch microspheres in therapy of hepatocellular carcinoma: a prospective trial

Background: This prospective randomized trial is designed to compare the performance of conventional transarterial chemoembolization (cTACE) using Lipiodol-only with additional use of degradable starch microspheres (DSM) for hepatocellular carcinoma (HCC) in BCLC-stage-B based on metric tumor response. Methods: Sixty-one patients (44 men; 17 women; range 44–85) with HCC were evaluated in this IRB-approved HIPPA compliant study. The treatment protocol included three TACE-sessions in 4-week intervals, in all cases with Mitomycin C as a chemotherapeutic agent. Multiparametric magnetic resonance imaging (MRI) was performed prior to the first and 4 weeks after the last TACE. Two treatment groups were determined using a randomization sheet: In 30 patients, TACE was performed using Lipiodol only (group 1). In 31 cases Lipiodol was combined with DSMs (group 2). Response according to tumor volume, diameter, mRECIST criteria, and the development of necrotic areas were analyzed and compared using the Mann–Whitney-U, Kruskal–Wallis-H-test, and Spearman-Rho. Survival data were analyzed using the Kaplan–Meier estimator. Results: A mean overall tumor volume reduction of 21.45% (± 62.34%) was observed with an average tumor volume reduction of 19.95% in group 1 vs. 22.95% in group 2 (p = 0.653). Mean diameter reduction was measured with 6.26% (± 34.75%), for group 1 with 11.86% vs. 4.06% in group 2 (p = 0.678). Regarding mRECIST criteria, group 1 versus group 2 showed complete response in 0 versus 3 cases, partial response in 2 versus 7 cases, stable disease in 21 versus 17 cases, and progressive disease in 3 versus 1 cases (p = 0.010). Estimated overall survival was in mean 33.4 months (95% CI 25.5–41.4) for cTACE with Lipiosol plus DSM, and 32.5 months (95% CI 26.6–38.4), for cTACE with Lipiodol-only (p = 0.844), respectively. Conclusions: The additional application of DSM during cTACE showed a significant benefit in tumor response according to mRECIST compared to cTACE with Lipiodol-only. No benefit in survival time was observed