Non-linear temperature dependency of ammonia and methane emissions from a naturally ventilated dairy barn

Ammonia (NH3) and methane (CH4) emissions from naturally ventilated dairy barns affect the environment and the wellbeing of humans and animals. Our study improves the understanding of the dependency of emission rates on climatic conditions with a particular focus on temperature. Previous investigations of the relation between gas emission and temperature mainly rely on linear regression or correlation analysis. We take up a preceding study presenting a multilinear regressionmodel based onNH3 and CH4 concentration and temperaturemeasurements between 2010 and 2012 in a dairy barn for 360 cows inNorthern Germany.We study scatter plots and non-linear regressionmodels for a subset of these data and show that the linear approximation comes to its limits when large temperature ranges are considered. The functional dependency of the emission rates on temperature differs among the gases. For NH3, the exponential dependency assumed in previous studies was proven. For methane, a parabolic relation was found. The emissions show large daily and annual variations and environmental impact factors like wind and humidity superimpose the temperature dependency but the functional shape in general persists. Complementary to the former insight that high temperature increases emissions, we found that in the case of CH4, also temperatures below 10 C lead to an increase in emissions from ruminal fermentation which is likely to be due to a change in animal activity. The improved prediction of emissions by the novel non-linear model may support more accurate economic and ecological assessments of smart barn concepts

What if extreme droughts occur more frequently? – Mechanisms and limits of forest adaptation in pine monocultures and mixed forests in Berlin-Brandenburg, Germany

Forests in Eastern Germany are already experiencing the detrimental effects of droughts, exemplified by the severe conditions of the 2018 drought year. With climate change, such extreme events are expected to become more frequent and severe. Previous work suggests that mixed forests exhibit greater resilience against droughts than monocultures. Our study aims to investigate the impact of increased frequency of extreme droughts, such as those seen in 2018, on biomass, structure and traits of forests in the Eastern German federal states of Berlin and Brandenburg. Utilizing the flexible-trait Dynamic Global Vegetation Model LPJmL-FIT, we simulate the growth and competition of individual trees in both, pine monoculture forest and mixed forest. The trees belong to different plant functional types or in case of pine forest are parametrized as Pinus sylvestris. We create drought scenarios from high resolution climate input data by re-shuffling the contemporary climate with increased frequencies of the extreme drought year 2018. For each scenario, we simulated vegetation dynamics over 800 simulation years which allowed us to analyze shorter-term impacts, in the first decades of the drought scenarios, as well as the long-term adaptation of the two forest types to those new climate normals. We evaluated the resulting long-term changes in biomass, plant functional traits and forest structure to examine the new equilibrium state emerging for each scenario. Our findings revealed nuanced responses to increased drought frequency. In pine monoculture forests, increased drought frequency reduced biomass and increased biomass variance, indicating higher system instability. Conversely, in mixed forests, biomass initially declined in scenarios with increased drought frequency but eventually recovered and even exceeded baseline levels after 100–150 years. We explain recovery and increase of biomass through two forest adaptation mechanisms; first, we saw a shift in the plant community towards broadleaved trees and second, plant traits shifted towards increased average wood density, decreased average tree height and increased average tree age. However, for the most extreme scenario with drought occurring each year, the adaptive capacity of the mixed forest was exceeded and the biomass halved compared to the baseline scenario. In our study, for the first time LPJmL-FIT is used with a resolution as high as 2 by 2 km², which allows us to observe spatial heterogeneity drought impacts within the Berlin-Brandenburg area. Pine monocultures suffered, especially in the warmer urban areas and mixed forests in the central-west of Brandenburg, benefitted in the long term. This study highlights the capacity of natural mixed forests in contrast to pine monocultures to adapt to increasing drought frequency up to a certain limit. The results underscore the importance of considering biodiversity in forest management strategies, especially with regard to more frequent dry periods under climate change

Tracer gas technique, air velocity measurement and natural ventilation method for estimating ventilation rates through naturally ventilated barns

Naturally ventilated barns have the advantage of providing an energy-efficient and low-noise micro-environment for animals.  Such barns are very common, especially for cattle, which are a major source of ammonia and methane emissions as well as other airborne pollutants. Emission fluxes are calculated as the product of the ventilation rate (VR) and the gas concentration.  The VR of naturally ventilated barns are directly influenced by atmospheric conditions.  Therefore, the estimation of VR involves high uncertainties; furthermore, there is no reference method for VR estimation.  For these reasons, three different methods were investigated to estimate VR through naturally ventilated dairy barns: (1) the tracer gas technique, using radioactive isotope Krypton-85 (85Kr), (2) the measurement of the air velocity through the barn openings, and (3) the natural ventilation method.  The investigations were performed in two naturally ventilated dairy barns (each with a volume of 5,670 m3) during mild (T≥17℃) and cold weather (T<17℃) conditions.  The VR ranged between 48,000 and 475,000 m3/h.  There was a significant (p<0.01) correlation between all three methods for barn A (Pearson’s correlation coefficient 0.59-0.86).  For barn B only, the tracer gas and the natural ventilation method showed a significant (p=0.03) correlation (Pearson’s correlation coefficient 0.62).  The season (mild or cold) and the VR estimation method both had a significant (p<0.03) effect on the estimated VR for both barns.  The outside wind speed had a significant (p<0.005) effect on the estimated VR for barn A.  For barn B, this effect was not significant (p=0.052).  The tracer gas technique used has the advantage of measuring the tracer with high resolution in time (1 Hz) and space (18 or more measured points).Keywords: Natural ventilation, tracer gas technique, radioactive isotope 85Kr, air velocity, air exchange rate, dairy barn  &nbsp

O-Verbrückte Angucyclinone, Verfahren zu ihrer Herstellung, sie enthaltende Arzneimittel und deren Verwendung

Es werden das verbrückte Angucyclinon Gephyromycin (1a) und Derivate dieser Verbindung nach der allgemeinen Formel 1 beschrieben sowie ein Verfahren zu ihrer Herstellung. Diese Substanzen erhöhen die intrazelluläre Calciumkonzentration in Neuronen. Weiterhin besitzen sie eine antibiotische Wirkung gegenüber Gram-positiven Bakterien

Debris disc candidates in systems with transiting planets

Debris discs are known to exist around many planet-host stars, but no debris dust has been found so far in systems with transiting planets. Using publicly available catalogues, we searched for infrared excesses in such systems. In the recently published Wide-Field Infrared Survey Explorer (WISE) catalogue, we found 52 stars with transiting planets. Two systems with one transiting "hot Jupiter" each, TrES-2 and XO-5, exhibit small excesses both at 12 and 22 microns at a > 3 sigma level. Provided that one or both of these detections are real, the frequency of warm excesses in systems with transiting planets of 2-4 % is comparable to that around solar-type stars probed at similar wavelengths with Spitzer's MIPS and IRS instruments. Modelling suggests that the observed excesses would stem from dust rings with radii of several AU. The inferred amount of dust is close to the maximum expected theoretically from a collisional cascade in asteroid belt analogues. If confirmed, the presence of debris discs in systems with transiting planets may put important constraints onto formation and migration scenarios of hot Jupiters.Comment: Accepted for publication in MNRAS Letter

Windkanaluntersuchungen an einem frei gelüfteten Milchviehstall

Die Luftdurchströmung von frei gelüfteten Ställen und der sich daraus ergebende Luftwechsel bestimmen das Stallklima und die Emissionsraten von Schadstoffen. In der Praxis sind diese Kenngrößen aufgrund der zeitlichen wie räumlichen Variabilität der vorherrschenden Prozesse nur schwer zu erfassen. Laborexperimente im Windkanal können unter kontrollierten Bedingungen statistisch repräsentative Daten erzeugen und damit Praxismessungen sinnvoll ergänzen. Windkanalmessungen der horizontalen Windgeschwindigkeitskomponenten wurden an einem Modell eines frei gelüfteten Milchviehstalles durchgeführt. Die Messungen erfolgten unter einer turbulenzarmen Anströmung, um den Einfluss der Einbauten im Stallmodell auf die Luftströmung erfassen zu können. Die Ergebnisse zeigen, dass die Einbauten und der Futtertisch die gemessenen Strömungsgrößen beeinflussen.The air exchange rate regulating the climate inside of natural ventilated livestock buildings is hard to determine in the field due to the variability of time and space of the dominant processes. Experiments in a wind tunnel laboratory can produce sound statistical and representative data obtained under controlled boundary conditions to complete data sets from the field. In this study, measurements of the horizontal wind components within a model of a natural ventilated barn were performed in the wind tunnel. The approach flow was chosen with low turbulence in order to gain knowledge on the influence of the installed equipment on the air flow. In fact, the measured profiles were influenced by the installed equipment and the feeding alley

Luftgeschwindigkeit und Hitzebelastung im Milchviehstall - Auswirkungen auf das Tierwohl

Das Stallklima hat einen wesentlichen Einfluss auf das Wohlbefinden und die Leistungsfähigkeit von Milchkühen. In der vorliegenden Untersuchung wurden Stallklimamessungen innerhalb und außerhalb eines frei gelüfteten Milchviehstalls, mit dem Fokus auf der Luftgeschwindigkeit im Fress- und Liegebereich, durchgeführt. Die Ergebnisse zeigten, dass die untersuchten Stallbereiche aufgrund der heterogen auftretenden Luftgeschwindigkeiten unterschiedlich belüftet wurden. Des Weiteren wurden die Stallklimamessungen mit physiologischen Tierparametern korreliert, um sie in Bezug auf das thermische Wohlbefinden der Tiere interpretieren zu können. An heißen Tagen wichen die analysierten Parameter deutlich von den übrigen Tagen ab.The investigation of barn climate and heat stress is important with regard to both welfare of dairy cows and performance. For this reason climate measurements in- and outside of a natural cross ventilated dairy barn have been conducted. Special emphasis was devoted to measurements on air speed within the animal occupied zone of the stable. The air speed was heterogeneously distributed and the results showed areas which were permanently less ventilated than others. However, climate measurements should be correlated to physiological animal parameters in order to interpret the barn conditions in respect of thermal comfort of the animals. On hot days, the parameters analyzed showed clear differences from the other days

The Tandem-L Mission Proposal: Monitoring Earth’s Dynamics with High Resolution SAR Interferometry

Tandem-L is a proposal for an innovative interferometric and polarimetric radar mission that enables the systematic monitoring of dynamic processes on the Earth surface. Important mission objectives are global forest height and biomass inventories, large scale measurements of millimetric displacements due to tectonic shifts, and systematic observations of glacier movements. The innovative mission concept and the high data acquisition capacity of Tandem-L provide a unique data source to observe, analyze and quantify the dynamics of a wide range of mutually interacting processes in the bio-, litho-, hydro- and cryosphere. By this, Tandem-L will be an essential step to advance our understanding of the Earth system and its intricate dynamics. This paper provides an overview of the Tandem-L mission concept and its main application areas. Performance predictions show the great potential of Tandem-L to acquire a wide range of bio- and geophysical parameters with high accuracy on a global scale. Innovative aspects like the employment of advanced digital beamforming techniques to improve performance and coverage are discussed in detail

Mixed Microscopic Eu2+ Occupancies in the Next-Generation Red LED Phosphor Sr[Li2Al2O2N2]:Eu2+ (SALON:Eu2+)

Red-emitting narrow-band phosphors are of utmost importance for next-generation white-light phosphor-converted light-emitting diodes (pc-wLEDs) for improved efficacy and optimized correlated color temperatures. A promising representative crystallizing in an ordered variant of the UCr4C4 structure type is Sr[Li2Al2O2N2]:Eu2+ (SALON:Eu2+) emitting at a desirable wavelength of 614 nm. Despite an expected eightfold coordination of the Eu2+ ions by four N3− and O2− ions, respectively, the exact local coordination symmetry and a 1:1 ratio between the two types of ligands is not straightforwardly proven by X-ray diffraction. Low-temperature luminescence spectroscopy in conjunction with ligand field theory are powerful alternatives to resolve local features of Eu2+ as its excited 4f65d1 configuration reacts sensitively to the polarity of the ligands. The dominant emission at 614 nm shows pronounced vibronic fine structure at 10 K. In addition, weak emission bands can be resolved at 570 and 650 nm even at a low doping concentration of 0.5 mol% and are assigned to Eu2+ ions being eightfold coordinated by N3− and O2− ions in a ratio different from 1:1. Due to the feature of vierer ring-type channels in SALON:Eu2+, those Eu2+ centers are sufficiently close for mutual energy transfer, which is characterized by time-resolved luminescence at 10 K