270 research outputs found
Grassland biodiversity can pay
No full textThe biodiversity–ecosystem functioning (BEF) literature provides strong evidence of the biophysical basis for the potential profitability of greater diversity but does not address questions of optimal management. BEF studies typically focus on the ecosystem outputs produced by randomly assembled communities that only differ in their biodiversity levels, measured by indices such as species richness. Landholders, however, do not randomly select species to plant; they choose particular species that collectively maximize profits. As such, their interest is not in comparing the average performance of randomly assembled communities at each level of biodiversity but rather comparing the best-performing communities at each diversity level. Assessing the best-performing mixture requires detailed accounting of species’ identities and relative abundances. It also requires accounting for the financial cost of individual species’ seeds, and the economic value of changes in the quality, quantity, and variability of the species’ collective output—something that existing multifunctionality indices fail to do. This study presents an assessment approach that integrates the relevant factors into a single, coherent framework. It uses ecological production functions to inform an economic model consistent with the utility-maximizing decisions of a potentially risk-averse private landowner. We demonstrate the salience and applicability of the framework using data from an experimental grassland to estimate production relationships for hay and carbon storage. For that case, our results suggest that even a risk-neutral, profit-maximizing landowner would favor a highly diverse mix of species, with optimal species richness falling between the low levels currently found in commercial grasslands and the high levels found in natural grasslands
Efficient Evaluation Method of System Concepts for Preliminary ECLSS Design Studies
No full textThe 44th International Conference on Environmental Systems was held in Tuscon, Arizona, USA on 13 July 2014 through 17 July 2014.Tilman Binder, Institute of Space Systems, GermanyEmil Nathanson, Institute of Space Systems, GermanyStefan Belz, Institute of Space Systems, GermanyStefanos Fasoulas, Institute of Space Systems, GermanyThe concept trade-off is a crucial step in the conceptual design of environmental control and life support systems (ECLSS). For this purpose, a computer program is developed by which a large number of options can be evaluated efficiently using parameter variation. The tool enables an automatic preliminary design of a complete ECLSS for time-averaged operation, and has proven to be a good supplement to discrete-time simulations. It is divided into two calculation parts. The first calculation balances mass flow rates of individual ECLSS components for time-averaged operation and is realized in a Microsoft Excel® spreadsheet file. The second calculation performs an iterative parameter variation in MATLAB®. Additionally to the variation of different component configurations, further parameters are optimized in terms of minimizing the equivalent system mass (ESM). These parameters include the amount of oxygen produced by water electrolysis and the operating levels of waste water regeneration and carbon dioxide reduction components. The algorithm is based on nested loops for the variation of the individual parameters and checking on linear dependencies or, alternatively, the bisection method for ESM optimization. The tool is demonstrated for an innovative free flyer concept in cis-lunar space. For the considered station, 160 different physicochemical configurations are evaluated
Wem gehören Autor-Leser-Texte?:Das geistige Eigentum, netzliterarische Standards, die Twitteratur von @tiny_tales und das Online-Schreibprojekt <i>morgen-mehr.de</i> von Tilman Rammstedt
No full textIn the ‘Gutenberg-Galaxy’, a strong divide between the author as a creator andthe reader as a subordinated figure helped to construct and protect authors’intellectual property rights. Net literature fundamentally suspends this strongdivide, and the protection of author’s works here restricts literary productivity.The analysis of author-reader-texts as produced in the twitterature by @tiny_tales and in the online-writing-project morgen-mehr.de by Tilman Rammstedtproves the necessity to develop standards of digital literary communication andopen data
Nemipterus randalli Russell 1986
No full textNemipterus randalli Russell, 1986 Material examined. No voucher specimens have been preserved for this species; unpreserved specimens examined by fourth author (29: 11.2–20.5 cm).Published as part of Bogorodsky, Sergey V., Alpermann, Tilman J., Mal, Ahmad O. & Gabr, Mohamed H., 2014, Survey of demersal fishes from southern Saudi Arabia, with five new records for the Red Sea, pp. 401-437 in Zootaxa 3852 (4) on page 426, DOI: 10.11646/zootaxa.3852.4.1, http://zenodo.org/record/22536
Tilman Nagels „,Authentizität‘ in der Leben-Mohammed-Forschung“. Eine Antwort
No full textThis contribution is a response to Tilman Nagel's essay “ ‘Authentizität’ in der Leben-Mohammed-Forschung” [‘Authenticity’ in the research on the Life of Mohammed] in which the author again presents the main theses argued in his monograph Mohammed. Leben und Legende and responds to criticism. Whereas his critics agree with Nagel that complete ‘authenticity’ is unattainable in principle, yet an asymptotic approximation of Mohammed as a figure is indeed possible, the way to attain such an approximation remains a matter of dispute. Contrary to Nagel, the proponents of the so-called isnad-cum-matn analysis hold this method, which offers the possibility to date ḥadīṯs (traditions) and reconstruct texts in circulation in the 1st cent. H., for one of the most successful towards achieving this goal. Another successful procedure of proven value is the evaluation and appraisal of the corpus of traditions traced back to ʿUrwa b. az-Zubayr (d. c. 712), one of the earliest and most important collectors of historical material in Islam. Proponents of both of these procedures do not apply the term ‘authentic’, as asserted by Nagel, in the sense of ‘what exactly happened’, but rather use this term if the transmitters of a tradition are historical figures and when the process of transmission is proven to have ensued as indicated in the chain of transmission
Tilman Nagels " ‚Authentizität‘ in der Leben-Mohammed-Forschung". Eine Antwort
No full textThis contribution is a response to Tilman Nagel's essay " ‘Authentizität' in der Leben-Mohammed-Forschung” [‘Authenticity' in the research on the Life of Mohammed] in which the author again presents the main theses argued in his monograph Mohammed. Leben und Legende and responds to criticism. Whereas his critics agree with Nagel that complete ‘authenticity' is unattainable in principle, yet an asymptotic approximation of Mohammed as a figure is indeed possible, the way to attain such an approximation remains a matter of dispute. Contrary to Nagel, the proponents of the so-called isnad-cum-matn analysis hold this method, which offers the possibility to date ḥadīṯs (traditions) and reconstruct texts in circulation in the 1st cent. H., for one of the most successful towards achieving this goal. Another successful procedure of proven value is the evaluation and appraisal of the corpus of traditions traced back to ʿUrwa b. az-Zubayr (d. c. 712), one of the earliest and most important collectors of historical material in Islam. Proponents of both of these procedures do not apply the term ‘authentic', as asserted by Nagel, in the sense of ‘what exactly happened', but rather use this term if the transmitters of a tradition are historical figures and when the process of transmission is proven to have ensued as indicated in the chain of transmissio
Identification of low molecular weight peptides targeting EpCAM and CD44v6
No full textDas Ribosomne Display ist eine etablierte Methode zur Identifizierung neuer Binder an bestimmte Zielstrukturen. Bei der Entwicklung neuer Pharmaka lag der Fokus in den letzten Jahrzenten vor allem bei der Entwicklung von spezifischen Antikörpern. In den letzten Jahren konnte allerdings ein Trendwandel in diesem Bereich beobachtet werden: Mittlerweile wird die Entwicklung von auf Peptiden basierenden Arzneimitteln immer weiter vorangetrieben. Dieser Wandel hat unter anderem mit den zahlreichen Vorteilen von Peptiden gegenüber Antikörpern zu tun: Peptide zeigen hohe Bindungsaffinitäten, treten besser ins Gewebe ein und haben eine geringe Immunogenität, wodurch sie weniger Nebenwirkungen auslösen. Zudem sind sie einfacher zu synthetisieren. Aufgrund dessen gewinnen Peptide auch im Bereich der Krebstherapie mehr und mehr an Bedeutung.Bei EpCAM und CD44v6 handelt es sich um zwei Krebs-assoziierte Proteine die in verschiedenen Tumoren überexprimiert werden und sich dadurch als mögliche Zielstrukturen zur Krebstherapie oder Diagnose eignen.Das Ziel der vorliegenden Doktorarbeit war es, spezifische Peptid-Binder gegen diese beiden Proteine zu identifizieren. Hierfür wurde die Methode des Ribosomen Displays gewählt. Im ersten Schritt musste zunächst das Ribosomen Display als kompletter Prozess im Labor etabliert werden. Dies beinhaltete auch die Etablierung von post translationalen Modifikationen und die Herstellung der Zielproteine EpCAM und CD44v6. Nach dem Screening wurde die Bindung aller verblieben Peptide mittels sogenanntem „crude extract“ ELISA analysiert. Hierbei konnten nur Binder gegen EpCAM identifiziert werden. Weitere Experimente umfassten die Spezifität und quantitative Analysen der bindenden Peptide. Hierbei konnten vier Peptide mit einer Bindungsaffinität von mindestens 200 nM beobachtet werden. Einer dieser Binder zeigte sogar bei einer Konzentration von 100 nM noch gute Bindungseigenschaften. Letztendlich war es leider nicht möglich diese in vitro basierten Ergebnisse auf Zellbasis zu reproduzieren. Keines der gefundenen Peptide zeigte eine Bindung zum nativen EpCAM Protein, welches auf der Zelloberfläche verschiedener Zelllinien exprimiert wurde. Die Ergebnisse zeigen die spezifische und strukturelle Bindung der selektierten Binder an Epitope, welche auf dem aufgereinigten EpCAM Protein vorhanden sind und beim nativen Protein wahrscheinlich maskiert werden
Weiterentwicklung und Anwendung von PICLas für die kombinierte Optik-Plume-Simulation von Ionenantrieben
No full textElectric propulsion systems are an efficient option for altitude/attitude control and orbit transfers of spacecraft. One example is the gridded ion thruster which ionizes the propellant and accelerates the ions of the generated plasma by a high-voltage grid system. This work deals with the numerical simulation of the plasma flow starting near the grid system in the ionization chamber and leaving the thruster with high velocity. These simulations give direct insight into the modeled, physical interrelationships and can be used to investigate questions arising in the industrial development process of ion propulsion systems. The required simulation method is challenging due to the high degree of flow rarefaction and the plasma state itself, including freely moving ions and electrons. Applicable simulation methods belong to a particle-based, gas-kinetic approach, such as Particle-In-Cell (PIC) for the simulation of electromagnetic interaction and the Direct Simulation Monte Carlo (DSMC) for inter-particle collisions. The effects resulting from the finite size of a real system can only be investigated by simulating the complete, three-dimensional thruster geometry which requires a large and complex simulation domain. Acceptable simulation times are realized by expanding and using the framework of the coupled PIC-DSMC code PICLas in combination with high performance computing systems
Nemipterus japonicus Bloch 1791
No full textNemipterus japonicus (Bloch, 1791) Material examined. SMF 35048 (7: 8.3–14.4 cm); SMF 35049 (3: 7.6–11.2 cm); KAUMM 98 (7: 8.1–12.9 cm); KAUMM 99 (4: 7.9–12.1 cm); unpreserved material examined by fourth author (504: 8.9–24.2 cm).Published as part of Bogorodsky, Sergey V., Alpermann, Tilman J., Mal, Ahmad O. & Gabr, Mohamed H., 2014, Survey of demersal fishes from southern Saudi Arabia, with five new records for the Red Sea, pp. 401-437 in Zootaxa 3852 (4) on page 426, DOI: 10.11646/zootaxa.3852.4.1, http://zenodo.org/record/22536
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