Purpose
The share of microbially degradable sediment organic matter (SOM) and the degradation rate depend, among others, on the intrinsic properties of SOM as well as on the type and concentration of ...terminal electron acceptors (TEA). Next to its role as TEA, molecular oxygen enhances SOM decay by oxygenase-mediated breakdown of complex organic molecules. This research investigated long-term SOM decay (> 250 days) under aerobic and anaerobic conditions to (1) provide a basis for sediment carbon flux estimates from the River Elbe estuary and (2) assess the potential for carbon burial in relation to redox conditions and dredging interventions.
Methods
Long-term aerobic and anaerobic SOM decay in fluid mud, pre-consolidated and consolidated sediment layers was investigated over three years along a transect of ca. 20 km through the Port of Hamburg, starting at the first hydrodynamically determined hotspot of sedimentation after the weir in Geesthacht. Absolute differences between aerobic and anaerobic cumulative carbon mineralization were calculated, as well as their ratio. Findings were correlated to a suite of solids and pore water properties.
Results
SOM decay followed first order multi-phase exponential decay kinetics. The ratio between C release under aerobic and anaerobic conditions ranged around 4 in the short-term, converging to a value of 2 in the long term. Strong gradients in absolute C release along the upstream–downstream transect did not reflect in a corresponding gradient of the aerobic-anaerobic ratio. C release was most strongly correlated to the water-soluble organic matter, in particular humic acids. Contact of anaerobically stabilized sediment with the oxygenated water phase induced significant release of carbon.
Conclusion
SOM degradability in the study area exhibited strong spatial gradients in relation to the organic matter source gradient but was mainly limited by the high extent of organic matter stabilization. Under these conditions, molecular oxygen as TEA provides little thermodynamic advantage. Carbon-sensitive sediment management, considering SOM reactivity patterns in stratified depositional areas, is a powerful strategy to reduce environmental impacts of dredging measures.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Purpose
Sediment organic matter (SOM) influences settling and thus the rheological behavior of suspended particles by enhancing flocculation or reducing surface charges by forming organo-mineral ...complexes that facilitate particle–particle interactions in consolidating sediments. It was, therefore, assumed that the microbial degradation of SOM and its spatio-temporal variability would affect sediment rheological properties and enhance port maintenance dredging and navigability of ports and waterways.
Methods
To investigate this effect, samples were taken at six locations along a transect of 30 river kilometers through the Port of Hamburg, Germany, during nine sampling campaigns within two years. The collected samples were divided into different layers based on the differences in visual consistency and strength. For analysis of SOM degradability, the samples were incubated in the laboratory for 250 days in glass bottles under aerobic and anaerobic conditions following the evolution of gas composition (CH4, CO2) and pressure in the bottle headspace over time. Yield stress was analyzed before and after the dissolved organic matter (DOM) decay using a rheometer with Couette geometry. Standard properties of solids and pore water were also analyzed.
Results
Shear strength decreased upon SOM decay under both anaerobic and aerobic conditions. Under anaerobic conditions, organic matter decay reduced static and fluidic yield stresses to an average of 74% and 79% of the fresh sample values. Consolidated layers at lower depths showed the highest absolute decrease in fluidic yield stress of up to –110 Pa due to a larger absolute amount of degradable organic matter in these layers in connection to higher bulk density. Pronounced spatial trends with higher changes in yield stress at upstream locations and lower yield stress changes at downstream locations coincided with a decreasing gradient of SOM degradability from upstream to downstream. Seasonal trends indicated that the investigation area is impacted by temporally changing factors.
Conclusion
The availability of easily degradable organic matter significantly affects sediment strength, especially under the anaerobic conditions, even when the mass loss of organic matter mass loss is small. Seasonal variability in yield stress changes upon SOM decay indicate that the site-specific responses were modulated by overarching seasonal effects impacting the entire investigation area. It was assumed that during an anaerobic decay, the formation of gas bubbles added an additional physical component to the effect of biological SOM decay.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Expansion tubes are an important type of test facility for the study of planetary entry flow-fields, being the only type of impulse facility capable of simulating the aerothermodynamics of ...superorbital planetary entry conditions from 10 to 20 km/s. However, the complex flow processes involved in expansion tube operation make it difficult to fully characterise flow conditions, with two-dimensional full facility computational fluid dynamics simulations often requiring tens or hundreds of thousands of computational hours to complete. In an attempt to simplify this problem and provide a rapid flow condition prediction tool, this paper presents a validated and comprehensive analytical framework for the simulation of an expansion tube facility. It identifies central flow processes and models them from state to state through the facility using established compressible and isentropic flow relations, and equilibrium and frozen chemistry. How the model simulates each section of an expansion tube is discussed, as well as how the model can be used to simulate situations where flow conditions diverge from ideal theory. The model is then validated against experimental data from the X2 expansion tube at the University of Queensland.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Context. Determining the source regions of meteorites is one of the major goals of current research in planetary science. Whereas asteroid observations are currently unable to pinpoint the source ...regions of most meteorite classes, observations of meteors with camera networks and the subsequent recovery of the meteorite may help make progress on this question. The main caveat of such an approach, however, is that the recovery rate of meteorite falls is low (<20%), implying that the meteoritic analogues of at least 80% of the observed falls remain unknown. Aims. Spectroscopic observations of incoming bolides may have the potential to mitigate this problem by classifying the incoming meteoritic material. Methods. To probe the use of spectroscopy to determine the meteoritic analogues of incoming bolides, we collected emission spectra in the visible range (320–880 nm) of five meteorite types (H, L, LL, CM, and eucrite) acquired in atmospheric entry-like conditions in a plasma wind tunnel at the Institute of Space Systems (IRS) at the University of Stuttgart (Germany). A detailed spectral analysis including a systematic line identification and mass ratio determinations (Mg/Fe, Na/Fe) was subsequently performed on all spectra. Results. It appears that spectroscopy, via a simple line identification, allows us to distinguish the three main meteorite classes (chondrites, achondrites and irons) but it does not have the potential to distinguish for example an H chondrite from a CM chondrite. Conclusions. The source location within the main belt of the different meteorite classes (H, L, LL, CM, CI, etc.) should continue to be investigated via fireball observation networks. Spectroscopy of incoming bolides only marginally helps precisely classify the incoming material (iron meteorites only). To reach a statistically significant sample of recovered meteorites along with accurate orbits (>100) within a reasonable time frame (10–20 years), the optimal solution may be the spatial extension of existing fireball observation networks.
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FMFMET, NUK, UL, UM, UPUK
The study is devoted to the estimation of sulfur dioxide emissions into the atmosphere based on satellite monitoring data in the area of the Norilsk industrial zone from 2010 to 2018. According to ...the measurements of the Ozone Monitoring Instrument - AURA satellite the NASA database is used. The maximum sulfur dioxide emissions amounted to 95 kt/month in November 2016, and the minimum - 0.185 kt/month in August 2011. The largest share of emissions is in January-May and November (90%). Comparison of the data obtained by the satellite method with the ground method revealed a difference of 30 to 65%, and with the method using aircraft carrier by 14 percent.
OBJECTIVES: Music-related symptoms can already be found among student musicians during their years of university training. The goals of the present study were to ascertain the state and developmental ...course of the student musicians' health and to test the effectiveness of a preventive
curriculum given to student musicians during their first two semesters at university. METHODS: Within a longitudinal, observational study, we assessed students' psychological and physical health during the first 2 years of university training. We compared data from the group of students
who had followed the prevention program (intervention group, IG, n = 144) with data of a comparison group (CG, n = 103) of students who had not followed the program. Using standardized questionnaires, we measured physical and psychological symptoms as well as health behavior in a sequential
plan (duration, 3.5 yrs). RESULTS: Student musicians (n = 247) showed elevated ratings in psychological and physical health in comparison with nonmusicians of the same age. These ratings decreased at the end of the students' second year. The prevention program had a preventive effect
on the students' psychological health: while IG students remained stable in their performance and powers of concentration, CG students got worse in those same areas. However, the prevention program did not reduce physical symptoms. In comparison with their younger colleagues, upper-level
students took more courses in body-oriented methods, relaxation, and mental techniques, which focus on preventive measures for musicians. CONCLUSION: At present, the study offers evidence supporting the use of the prevention curriculum for young musicians. In higher music education, preventive
education has a positive impact on students' performance and their attitude toward health. The preventive curriculum does not have an effect on preexisting physical symptoms, and those symptoms related to the student musicians' activity should rather be treated in an additional
therapeutic setting.
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BFBNIB, NMLJ, NUK, PNG, UL, UM, UPUK
Summary Vocal fold oscillation patterns in vocal register transitions are still unclarified. The vocal fold oscillations and the open quotient were analyzed with high-speed digital imaging (HSDI) and ...electroglottography (EGG) in 18 male untrained subjects singing a glissando from modal to the falsetto register. Results reveal that the open quotient changed with register in both HSDI and EGG. The in-class correlations for different HSDI and EGG determinations of the open quotient were high. However, we found only weak interclass correlations between both methods. In 10 subjects, irregularities of vocal fold vibration occurred during the register transition. Our results confirm previous observations that falsetto register is associated with a higher open quotient compared with modal register. These data suggest furthermore that irregularities typically observed in audio and electroglottographic signals during register transitions are caused by irregularities in vocal fold vibration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The ability of music to create differentiating effects on subjects’
impressions of product endorsers and brands of an advertisement were examined based
on the theory of ‘musical fit’. Subjects (N = ...132)
listened to one of three versions of a radio commercial in which the music varied in
each version. The music selections differed in style, tempo, rhythm, etc., but
matched product and message of the commercial in terms of ‘musical
fit’. After listening to the commercial, subjects rated the
endorser's personality via the external version of a personality inventory.
Impressions of the brand were measured using semantic differentials. The results
concur with previous findings: depending on musical style, music can lead to
significantly different impressions of the endorser as well as the brand without
affecting general evaluations of the product. Based on sex, interesting differences
concerning music perception and its impacts were found. Self-critical annotations
and suggestions for practitioners and future studies are discussed.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
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