gasfluxes - ein R-Package für die Flussberechnung

Treibhausgasmessungen werden immer noch überwiegend mit manuellen Messhauben und anschließender Analyse der genommenen Luftproben am Gaschromatographen durchgeführt. Zur Flussberechnung können lineare oder nicht-lineare Konzentrations-Zeit-Modelle verwendet werden. Um diese reproduzierbar und effizient zu fitten, sind weitgehend automatisierte Verfahren notwendig. Um die Güte der Anpassung beurteilen zu können und die Entscheidung für ein Modell zu unterstützen, sollten dabei diverse statistische Kenngrößen ausgegeben werden. Dies leistet das R-Package gasfluxes, das seit Ende 2016 auch auf dem Comprehensive R Archive Network (CRAN) verfügbar ist (1). Es wird das Konzept des Package sowie der beabsichtigte Workflow vorgestellt. Anregungen zu Verbesserungen und Erweiterungen sind willkommen

BECCS potential in Brazil: Achieving negative emissions in ethanol and electricity production based on sugar cane bagasse and other residues

Stabilization at concentrations consistent with keeping global warming below 2 °C above the pre-industrial level will require drastic cuts in Greenhouse Gas (GHG) emissions during the first half of the century; net negative emissions approaching 2100 are required in the vast majority of current emission scenarios. For negative emissions, the focus has been on bioenergy with carbon capture and storage (BECCS), where carbon-neutral bioenergy would be combined with additional carbon capture thus yielding emissions lower than zero. Different BECCS technologies are considered around the world and one option that deserves special attention applies CCS to ethanol production. It is currently possible to eliminate 27.7 million tonnes (Mt) of CO2 emissions per year through capture and storage of CO2 released during fermentation, which is part of sugar cane-based ethanol production in Brazil. Thus, BECCS could reduce the country’s emissions from energy production by roughly 5%. Such emissions are additional to those due to the substitution of biomass-based electricity for fossil-fueled power plants. This paper assesses the potential and cost effectiveness of negative emissions in the joint production system of ethanol and electricity based on sugar cane, bagasse, and other residues in Brazil. An important benefit is that CO2 can be captured twice along the proposed BECCS supply chain (once during fermentation and once during electricity generation). This study only considers BECCS from fermentation because capturing such CO2 is straightforward, thus potentially representing a cost-effective mitigation option for Brazil compared to other alternatives. The assessment shows that fuel prices would increase by less than 3.5% due to the adoption of BECCS from fermentation, while increasing investors’ revenues are sufficient to compensate for the investment required. With appropriate government subsidies, or by sharing BECCS costs between all car fuels and all electricity supplied by hydro and bioelectricity, the increment in ethanol and electricity prices could be less than 1% for the final consumer. Meanwhile it would supply 77.3% of all cars’ fuel (private cars) and 17.9% of all electricity in Brazil

Large Exchange Bias, High Dielectric Constant, and Outstanding Ionic Conductivity in a Single‐Phase Spin Glass

The multigram synthesis of K2[Fe3S4] starting from K2S and FeS is presented, and its electronic and magnetic properties are investigated. The title compound obtains a defect variant of the K[Fe2Se2] structure type. Dielectric and impedance measurements indicate a dielectric constant of 1120 at 1 kHz and an outstanding ionic conductivity of 24.37 mS cm–1 at 295 K, which is in the range of the highest reported value for potential solid‐state electrolytes for potassium‐ion batteries. The Seebeck coefficient of the n‐type conductor amounts to −60 µV K−1 at 973 K. The mismatch of the measured electrical resistivity and the predicted metal‐like band structure by periodic quantum chemical calculations indicates Mott insulating behavior. Magnetometry demonstrates temperature‐dependent, large exchange bias fields of 35 mT, as a consequence of the coexistence of spin glass and antiferromagnetic orderings due to the iron vacancies in the lattice. In addition, the decreasing training effects of 34% in the exchange bias are identified at temperatures lower than 20 K. These results demonstrate the critical role of iron vacancies in tuning the electronic and magnetic properties and a multifunctional material from abundant and accessible elements

Dem Stickstoff auf der Spur: N2O Prozesse und Nmin Dynamik nach Grünlanderneuerung

Eine weit verbreitete Maßnahme des Grünlandmanagements, die zur Beseitigung von Narbenschäden und zur Steigerung der Futterqualität in unproduktiven Grünländern angewendet wird, ist die Grünlanderneuerung. Die mechanische Bearbeitung von Grünlandböden und die dadurch gesteigerte Mineralisation durch den Abbau organischer Bodensubstanz und der alten Grasnarbe kann zu hohen N-Verlusten in Form des klimarelevanten Treibhausgases Lachgas (N2O) und/oder Nitratauswaschung (NO3-) führen. Bisher gibt es jedoch über die Dauer des beschriebenen Effektes, sowie den Einfluss unterschiedlicher Grünlanderneuerungstechniken nur wenige Informationen. Insbesondere für die nationale Treibhausgasbilanzierung ist es jedoch von Bedeutung, die Prozesse der N2O Umsetzung und ihre Quellen zu kennen und zu erfassen, da sich nur so Maßnahmen zur Emissionsminderung ableiten lassen. Zu diesem Zweck wurde ein Parzellenversuch (2013-2015) auf zwei Standorten (Plaggenesch, Anmoorgley) in der Nähe von Oldenburg (Niedersachsen) mit unterschiedlichen Erneuerungsvarianten etabliert. Als Referenzvarianten dienten: Grünlandumwandlung in Ackerland (Mais) und langjähriges Dauergrünland. Die N2O Flüsse und die Dynamik des mineralischen N (Nmin) wurden über einen Zeitraum von zwei Jahren untersucht. Zusätzlich wurden Nmin Profile (0-90 cm) genutzt, um den N-Verlust über Winter zu quantifizieren und das Risiko einer möglichen NO3- Auswaschung abzuschätzen. Obwohl die N2O Flüsse für einen kurzen Zeitraum (2 Monate) nach der Bearbeitung erhöht waren, konnte kein Jahreseffekt festgestellt werden. Im ersten Winter nach dem Aufbrechen der alten Grasnarbe trat jedoch für den Plaggenesch ein erhöhtes Risiko für NO3- Auswaschung auf. Die Untersuchung der N2O-Produktionswege und der N2O-Reduktion zu N2 (dem Endprodukt der Denitrifikation) erfolgte unter Nutzung stabiler Isotope. Hierzu wurde die 15N-Gasflussmethode im Sommer 2014 angewendet (1). Zusätzlich wurden natürlich vorhandene stabile Isotopensignaturen im bodenbürtigen N2O (δ15NbulkN2O, δ18ON2O und δ15NSPN2O = intramolekulare Verteilung von 15N im N2O Molekül) genutzt, um Quellen der N2O-Bildung im ersten Jahr nach Grünlanderneuerung (2013-2014) zu ermitteln. Auf dem Anmoorgley wurden große N-Verluste durch den Prozess der Denitrifikation bestimmt, wobei N2 die Emissionen dominerte. Für den Plaggenesch konnten generell geringere gasförmige Verluste festgestellt werden

Working conditions and Work-Family Conflict in German hospital physicians: psychosocial and organisational predictors and consequences

<p>Abstract</p> <p>Background</p> <p>Germany currently experiences a situation of major physician attrition. The incompatibility between work and family has been discussed as one of the major reasons for the increasing departure of German physicians for non-clinical occupations or abroad. This study investigates predictors for one particular direction of Work-Family Conflict – namely work interfering with family conflict (WIF) – which are located within the psychosocial work environment or work organisation of hospital physicians. Furthermore, effects of WIF on the individual physicians' physical and mental health were examined. Analyses were performed with an emphasis on gender differences. Comparisons with the general German population were made.</p> <p>Methods</p> <p>Data were collected by questionnaires as part of a study on <it>Psychosocial work hazards and strains of German hospital physicians </it>during April–July 2005. Two hundred and ninety-six hospital physicians (response rate 38.9%) participated in the survey. The Copenhagen Psychosocial Questionnaire (COPSOQ), work interfering with family conflict scale (WIF), and hospital-specific single items on work organisation were used to assess WIF, its predictors, and consequences.</p> <p>Results</p> <p>German hospital physicians reported elevated levels of WIF (mean = 74) compared to the general German population (mean = 45, <it>p </it>< .01). No significant gender difference was found. Predictors for the WIF were lower age, high quantitative demands at work, elevated number of days at work despite own illness, and consequences of short-notice changes in the duty roster. Good sense of community at work was a protective factor. Compared to the general German population, we observed a significant higher level of quantitative work demands among hospital physicians (mean = 73 vs. mean = 57, <it>p </it>< .01). High values of WIF were significantly correlated to higher rates of personal burnout, behavioural and cognitive stress symptoms, and the intention to leave the job. In contrast, low levels of WIF predicted higher job satisfaction, better self-judged general health status, better work ability, and higher satisfaction with life in general. Compared to the German general population, physicians showed significantly higher levels of individual stress and quality of life as well as lower levels for well-being. This has to be judged as an alerting finding regarding the state of physicians' health.</p> <p>Conclusion</p> <p>In our study, work interfering with family conflict (WIF) as part of Work-Family Conflict (WFC) was highly prevalent among German hospital physicians. Factors of work organisation as well as factors of interpersonal relations at work were identified as significant predictors for WIF. Some of these predictors are accessible to alteration by improving work organisation in hospitals.</p

The interplay between total mercury, methylmercury and dissolved organic matter in fluvial systems: A latitudinal study across Europe.

Large-scale studies are needed to identify the drivers of total mercury (THg) and monomethyl-mercury (MeHg) concentrations in aquatic ecosystems. Studies attempting to link dissolved organic matter (DOM) to levels of THg or MeHg are few and geographically constrained. Additionally, stream and river systems have been understudied as compared to lakes. Hence, the aim of this study was to examine the influence of DOM concentration and composition, morphological descriptors, land uses and water chemistry on THg and MeHg concentrations and the percentage of THg as MeHg (%MeHg) in 29 streams across Europe spanning from 41°N to 64 °N. THg concentrations (0.06-2.78 ng L-1) were highest in streams characterized by DOM with a high terrestrial soil signature and low nutrient content. MeHg concentrations (7.8-159 pg L-1) varied non-systematically across systems. Relationships between DOM bulk characteristics and THg and MeHg suggest that while soil derived DOM inputs control THg concentrations, autochthonous DOM (aquatically produced) and the availability of electron acceptors for Hg methylating microorganisms (e.g. sulfate) drive %MeHg and potentially MeHg concentration. Overall, these results highlight the large spatial variability in THg and MeHg concentrations at the European scale, and underscore the importance of DOM composition on mercury cycling in fluvial systems

Diffusion processes of soluble organic substances in soil and their effect on ecological processes.

This thesis investigates diffusion of dissolved organic matter (DOM) and its interaction with other soil processes in the soil ecosystem. Intrinsic diffusion characteristics of DOM were studied as well as diffusion of DOM in the vicinity of microbial and organic matter heterogeneities in soil. It is shown that diffusion properties of different DOM fractions are surprisingly similar and that DOM can at the most contain minor amounts of humic substances due to its mean molecular size. The interaction of degradation and diffusion after addition of litter respectively microbial hot-spots to soil is described. To distinguish carbon fluxes soil was supplemented with 14C-labeled biomass and a 14C-labeled pesticide, respectively