2,111 research outputs found
Heavy Metal and Contaminant Loading in the Oder River Floodplains and Consequences for Livestock Management
The predominately pristine lower Oder floodplains have experienced sedimentation and enrichment of heavy metals and contaminants since the start of industrialization in the region. With the creation of the German-Polish National Park, which included the flooded grassland area, intensive milk production has been prohibited. The objective of this research was to estimate the impact of the floodplain heavy metal and contaminant levels on the lower Oder region. Soil and plant content were analyzed for three transects according to accepted DIN methods. High content in soil did not consistently result in high plant contents; however, higher content levels were often observed in hollows. A particular vegetation characteristic of heavy metal soil content was not observed. Exceeded levels in terms of the German fodder ordinance were most frequently detected for Cadmium and Manganese. Extensive pasturing of suckler cows and young or beef cattle is possible with the exception of problem areas
Long Term Results for the Naturalisation of River Valley Grassland in the Lower Floodplains of the River Oder
The flooded grassland area in the lower reaches of the River Oder covers about 10,000 ha, of which 4,000 ha are situated on the German side and the remainder in Poland. In spite of extreme flooding conditions (annual winter flooding from 15 Dec. to 15 April and occasional summer flooding) the area was used very intensively in GDR times. After the political change in 1989, the management of the cross-border GermanPolish National Park, which was situated in this area, was changed abruptly to extensive grassland utilisation. This paper reports on changes in the composition and productivity of the grassland
Scanning rotational Raman lidar at 355 nm for the measurement of tropospheric temperature fields
International audienceFor high-resolution measurements of temperature fields in the atmospheric boundary layer and the lower free troposphere a scanning eye-safe lidar which deploys the rotational Raman technique at 355 nm was developed. To optimize the filters of the receiver for both high nighttime and daytime performance, detailed simulation studies have been performed. The receiver is fiber-coupled to a sequential setup of multicavity interference filters used under small angles of incidence. Examples of nighttime and daytime measurements with the system which has a total power-aperture-efficiency product of 0.006 W m2 are presented. Noontime temperature measurements with a temporal resolution of 60 s result in 1-sigma statistical temperature uncertainty of <1 K up to 1 km height and <2 K up to 2 km height. With an integration time of 60 min and a gliding average of 750 m a 1-sigma statistical temperature uncertainty of <1 K up to 14 km height is achieved during night
The life cycle of starbursting circumnuclear gas discs
High-resolution observations from the sub-mm to the optical wavelength regime
resolve the central few 100pc region of nearby galaxies in great detail. They
reveal a large diversity of features: thick gas and stellar discs, nuclear
starbursts, in- and outflows, central activity, jet interaction, etc.
Concentrating on the role circumnuclear discs play in the life cycles of
galactic nuclei, we employ 3D adaptive mesh refinement hydrodynamical
simulations with the RAMSES code to self-consistently trace the evolution from
a quasi-stable gas disc, undergoing gravitational (Toomre) instability, the
formation of clumps and stars and the disc's subsequent, partial dispersal via
stellar feedback. Our approach builds upon the observational finding that many
nearby Seyfert galaxies have undergone intense nuclear starbursts in their
recent past and in many nearby sources star formation is concentrated in a
handful of clumps on a few 100pc distant from the galactic centre. We show that
such observations can be understood as the result of gravitational
instabilities in dense circumnuclear discs. By comparing these simulations to
available integral field unit observations of a sample of nearby galactic
nuclei, we find consistent gas and stellar masses, kinematics, star formation
and outflow properties. Important ingredients in the simulations are the
self-consistent treatment of star formation and the dynamical evolution of the
stellar distribution as well as the modelling of a delay time distribution for
the supernova feedback. The knowledge of the resulting simulated density
structure and kinematics on pc scale is vital for understanding inflow and
feedback processes towards galactic scales.Comment: accepted by MNRA
Relationships between skin follicle characteristics and fibre properties of Suri and Huacaya alpacas and Peppin Merino sheep
We aimed to quantify the number, type and arrangement of skin follicles in Huacaya and Suri alpaca skin and correlate their follicle characteristics with fibre traits of harvested fibre and compared these relationships with those of Merino sheep. Fibre and skin samples were collected from the mid-side of 12 Huacaya alpacas, 24 Suri alpacas and 10 Merino sheep. The mean fibre diameter (MFD ± s.e.) of the Huacaya and Suri were: 35.5 ± 0.9 and 28.3 ± 1.0 μm, respectively. The follicle groups found for alpacas were very different from the normal trio of primary follicles found in sheep and goats. The follicle group of the alpacas consisted of a single primary follicle surrounded by a variable number of secondary follicles. The mean ± s.e. primary follicle density was 3.1 ± 0.3 and 2.7 ± 0.1 follicles/mm2 for Huacaya and Suri, respectively. The mean ± s.e. secondary follicle density (SFD) was 13.7 ± 1.2 and 17.5 ± 0.6 follicles/mm2 for Huacaya and Suri, respectively. The mean ± s.e. ratio of secondary to primary follicles (S/P ratio) was 5.1 ± 0.5 for the Huacaya and 7.3 ± 0.2 for the Suri alpacas. The sheep had higher S/P ratios and SFD, lower MFD and produced significantly heavier fleeces. The key correlations found between traits in alpacas include a negative correlation between SFD and MFD (r = –0.71, P = 0.001) and a negative correlation between S/P ratio and MFD (r = –0.44, P = 0.003) and a positive correlation between S/P ratio and total follicle density (r = 0.38, P = 0.010). The study revealed that important relationships exist between alpaca skin follicle characteristics and fibre characteristics. It was the number of secondary follicles in a group that imparts density and a corresponding reduced MFD.<br /
Supporting The Modelling In MBSE By Applying Product Generation Engineering Using Electronic Compact Actuators As An Example
The development of a new motor can be a high effort. In this paper, Model-based Systems Engineering (MBSE) is applied to model the second generation of an electronic compact actuator (ECA). This paper focuses on the traceability between model elements from previous product generations. By integrating the approach of the PGE - Product Generation Engineering in MBSE, developers can store more relevant information in the model; they can accomplish automatic calculations of derived factors and build models more efficiently in further product developments
Nutrient Balances of Rewetted Fens – Groundwater Lysimeter Results
With the raising of groundwater levels to protect fens and the climate, there may be a risk of nutrients, such as nitrogen or potassium, leaching into the groundwater. Great amounts of nutrients, which are accumulated largely by peat forming plants like Phragmites australis and Carex spec., are conveyed into rewetted fens through high amounts of introduced water. Nitrogen leaching into the groundwater is very low even at the beginning of flooding and there is no sudden, pronounced leaching. Only a portion of potassium is taken up by plants whereas the rest might be found in the groundwater. Increasing nutrient inputs must be expected as soon as more contaminated water is added contributing to the regeneration of groundwater and increasing the pollution with nutrients at once
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