TY - JOUR A1 - Wacker, Alexander A1 - Marzetz, Vanessa A1 - Spijkerman, Elly T1 - Interspecific competition in phytoplankton drives the availability of essential mineral and biochemical nutrients JF - Ecology : a publication of the Ecological Society of America N2 - The underlying mechanisms and consequences of competition and diversity are central themes in ecology. A higher diversity of primary producers often results in higher resource use efficiency in aquatic and terrestrial ecosystems. This may result in more food for consumers on one hand, while, on the other hand, it can also result in a decreased food quality for consumers; higher biomass combined with the same availability of the limiting compound directly reduces the dietary proportion of the limiting compound. Here we tested whether and how interspecific competition in phytoplankton communities leads to changes in resource use efficiency and cellular concentrations of nutrients and fatty acids. The measured particulate carbon : phosphorus ratios (C:P) and fatty acid concentrations in the communities were compared to the theoretically expected ratios and concentrations of measurements on simultaneously running monocultures. With interspecific competition, phytoplankton communities had higher concentrations of the monounsaturated fatty acid oleic acid and also much higher concentrations of the ecologically and physiologically relevant long-chain polyunsaturated fatty acid eicosapentaenoic acid than expected concentrations based on monocultures. Such higher availability of essential fatty acids may contribute to the positive relationship between phytoplankton diversity and zooplankton growth, and may compensate limitations by mineral nutrients in higher trophic levels. KW - biodiversity KW - C:P ratio KW - competition KW - eicosapentaenoic acid KW - elemental composition KW - EPA KW - food quality KW - minerals KW - phosphorus KW - polyunsaturated fatty acids KW - PUFA KW - resource use efficiency Y1 - 2015 U6 - https://doi.org/10.1890/14-1915.1 SN - 0012-9658 SN - 1939-9170 VL - 96 IS - 9 SP - 2467 EP - 2477 PB - Wiley CY - Washington ER - TY - JOUR A1 - Lukas, Marcus A1 - Wacker, Alexander T1 - Constraints by oxygen and food quality on carbon pathway regulation: a co-limitation study with an aquatic key herbivore JF - Ecology : a publication of the Ecological Society of America N2 - In food webs, herbivores are often constrained by low food quality in terms of mineral and biochemical limitations, which in aquatic ecosystems can co-occur with limited oxygen conditions. As low food quality implies that carbon (C) is available in excess, and therefore a regulation to get rid of excess C is crucial for the performance of consumers, we examined the C pathways (ingestion, feces release, excretion, and respiration) of a planktonic key herbivore (Daphnia magna). We tested whether consumer C pathways increase due to mineral (phosphorus, P) or biochemical (cholesterol and fatty acid) limitations and how these regulations vary when in addition oxygen is low. Under such conditions, at least the capability of the upregulation of respiration may be restricted. Furthermore, we discussed the potential role of the oxygen-transporting protein hemoglobin (Hb) in the regulation of C budgets. Different food quality constraints led to certain C regulation patterns to increase the removal of excess dietary C: P-limited D. magna increased excretion and respiration, while cholesterol-limited Daphnia in addition upregulated the release of feces. In contrast, the regulative effort was low and only feces release increased when D. magna was limited by a long-chain polyunsaturated fatty acid (eicosapentaenoic acid, EPA). Co-limiting oxygen did not always impact the discharge of excess C. We found the food-quality-induced upregulation of respiration was still present at low oxygen. In contrast, higher excretion of excess C was diminished at low oxygen supply. Besides the effect that the Hb concentration increased under low oxygen, our results indicate a low food-quality-induced increase in the Hb content of the animals. Overall, C budgeting is phenotypically plastic towards different (co-) limiting scenarios. These trigger specific regulation responses that could be the result of evolutionary adaptations. KW - carbon budget KW - carbon stoichiometry KW - cholesterol KW - co-limitation KW - Daphnia KW - EPA KW - hemoglobin KW - oxygen KW - phosphorus KW - polyunsaturated fatty acid KW - zooplankton Y1 - 2014 SN - 0012-9658 SN - 1939-9170 VL - 95 IS - 11 SP - 3068 EP - 3079 PB - Wiley CY - Washington ER - TY - BOOK A1 - Neuhaus, Christian A1 - Polze, Andreas A1 - Chowdhuryy, Mohammad M. R. T1 - Survey on healthcare IT systems : standards, regulations and security N2 - IT systems for healthcare are a complex and exciting field. One the one hand, there is a vast number of improvements and work alleviations that computers can bring to everyday healthcare. Some ways of treatment, diagnoses and organisational tasks were even made possible by computer usage in the first place. On the other hand, there are many factors that encumber computer usage and make development of IT systems for healthcare a challenging, sometimes even frustrating task. These factors are not solely technology-related, but just as well social or economical conditions. This report describes some of the idiosyncrasies of IT systems in the healthcare domain, with a special focus on legal regulations, standards and security. N2 - IT Systeme für Medizin und Gesundheitswesen sind ein komplexes und spannendes Feld. Auf der einen Seite stehen eine Vielzahl an Verbesserungen und Arbeitserleichterungen, die Computer zum medizinischen Alltag beitragen können. Einige Behandlungen, Diagnoseverfahren und organisatorische Aufgaben wurden durch Computer überhaupt erst möglich. Auf der anderen Seite gibt es eine Vielzahl an Fakturen, die Computerbenutzung im Gesundheitswesen erschweren und ihre Entwicklung zu einer herausfordernden, sogar frustrierenden Aufgabe machen können. Diese Faktoren sind nicht ausschließlich technischer Natur, sondern auch auf soziale und ökonomische Gegebenheiten zurückzuführen. Dieser Report beschreibt einige Besondenderheiten von IT Systemen im Gesundheitswesen, mit speziellem Fokus auf gesetzliche Rahmenbedingungen, Standards und Sicherheit. T3 - Technische Berichte des Hasso-Plattner-Instituts für Digital Engineering an der Universität Potsdam - 45 KW - EPA KW - Elektronische Patientenakte KW - Sicherheit KW - Privacy KW - Standards KW - Gesetze KW - EHR KW - electronic health record KW - security KW - privacy KW - standards KW - law Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-51463 SN - 978-3-86956-128-8 PB - Universitätsverlag Potsdam CY - Potsdam ER -