3,002 research outputs found
Carbon in soils
Carbon is the fourth most common element in the galaxy(by mass) but does not even rank in the twelve most abundant elements on Earth. By far the most abundant source of carbon on Earth is in the crust as inorganic rocks such as calcite and limestone in marine and sedimentary deposits. These rocks have taken many millions of years to form. Other major inorganic sources are in the oceans and atmosphere
Nitrogen, soils and environment
The article discusses the risk of damaging the environment brought by nitrogen fertilisers which are used for increasing agricultural productivity. The oxidation of ammonium allows for the formation of nitrate. Troposphere ozone and aerosols are produced through the increase of reactive nitrogen in the atmosphere
Adiabatic connection at negative coupling strengths
The adiabatic connection of density functional theory (DFT) for electronic
systems is generalized here to negative values of the coupling strength
(with {\em attractive} electrons). In the extreme limit
a simple physical solution is presented and its implications
for DFT (as well as its limitations) are discussed. For two-electron systems (a
case in which the present solution can be calculated exactly), we find that an
interpolation between the limit and the opposite limit of
infinitely strong repulsion () yields a rather accurate
estimate of the second-order correlation energy E\cor\glt[\rho] for several
different densities , without using virtual orbitals. The same procedure
is also applied to the Be isoelectronic series, analyzing the effects of
near-degeneracy.Comment: 9 pages, submitted to PR
Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture
The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD haā»Ā¹, with a total annual application of 33 kg haā»Ā¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 Ā± 3 days (mean and standard deviation)
Towards controlled microneedle-mediated intradermal immunization
Traditionally, vaccines are
administered intramuscularly using conventional hypodermic needles, which cause
pain and distress. Microneedles are very short needles (smaller than 1 mm) that are
practically invisible to the naked eye. Microneedles may administer vaccine
into the skin in a pain-free manner. By using the intradermal route for
immunization, a high number of immune cells in the skin are targeted, which may
result in more efficient immunization. In this thesis, several aspects of
intradermal immunization were investigated by using hollow microneedles. As
differently specialized immune cells reside at different depths in skin,
immunization outcomes as function of injection depth in skin were investigated
to determine effects of injection depth. Furthermore, as prolonged antigen
exposure may enhance immune responses, immunization outcomes resulting from
repeated fractional intradermal dosing schedules were compared to those
resulting from bolus dosing schedules. Finally, a layer-by-layer coating
approach was developed for solid microneedle arrays. In the layer-by-layer
coating approach, alternating layers of antigen and polymer are coated onto the
surface of microneedle arrays. This approach enabled coating and intradermal
delivery of a precise amount of antigen. Intradermal immunization using
layer-by-layer coated microneedle arrays resulted in effective immunization. In
conclusion, these studies provide important insights towards controlled
microneedle-mediated intradermal immunization.This study was funded by the Dutch Technology Foundation STW, which is part of the Netherlands Organization for Scientific Research (NWO), and which is partly funded by the Ministry of Economic Affairs (project no. 11259).Drug Delivery Technolog
Duurzaam beheer volgens SBB
De moeite die terreinbeherende organisaties hebben om de achteruitgang van de biodiversiteit in Nederland te stoppen heeft te maken met de verstoring van landschapsecologische processen. Het herstel daarvan is de sleutel tot de instandhouding van natuurwaarden. Op basis van dat uitgangspunt heeft Staatsbosbeheer een afwegingskader voor een duurzaam natuurbeheer in de toekomst ontwikkeld. met dit kader wil de organisatie een bijdrage leveren aan de discussie over de herijking van de EH
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