Seed coating for delayed germination

The diffuse leaching of plant nutrients from agricultural soils is part of the problem of the eutrophication of fresh water systems and coastal sea waters. Among the measures taken to reduce the leaching is keeping the soil with plant cover during autumn and winter. In areas with a predominance of annual crops this can be achieved by the undersowing of catch crops. In the current work it was investigated how the time of undersowing affected the barley (Hordeum distichon L.) crop and the catch crop biomass production. As catch crops Italian ryegrass (Lolium multiflorum L.), perennial ryegrass (Lolium perenne Lam.) and red clover (Trifolium pratense L.) were used. The biomass of the catch crop was markedly reduced with delayed undersowing, but net biomass production in late autumn was generally not affected. On light soil the barley yield was only to a small extent affected by the undersown catch crop, and with delayed undersowing the yield was even less affected. On heavier soil the barley yield was only marginally affected regardless of time of catch crop undersowing. An alternative to the undersowing of catch crops would be relay cropping of two cereal crops, one spring crop and one winter crop. As their initial competitive capacities are similar there is a risk that the winter crop will affect the spring crop yield adversely. To be able to set the competitive relationship between the crops favourably for the relay cropping system to be effective, a means to delay the winter crop germination is needed. Delayed undersowing has the risk of damaging the spring crop by the drilling procedur itself, and this was also noticed in the catch crop field experiments. In a couple of experiments the technique of coating seeds with polymers to achieve delayed germination was explored. The materials used were cellulose lacquer (in one experiment with the addition of lanolin) or an acrylic plastic, a so called primer. Wheat (Triticum aestivum L.) and oil seed rape (Brassica napus L.) were coated in house with several coating levels and germinated under controlled conditions in Petri dishes. In one experiment the coated seeds were germinated under three different temperature levels and three different moisture levels. It was found that delays could be achieved and that with increasing coating level the delays increased. It was also found that at low germination temperature (5.5 °C) for plastic coated seeds there was almost no difference in temperature sum needed from sowing to germination regardless of coating level. At high germination temperature (13.9 °C) there was a marked increase in temperature sum needed to germination and it increased with increasing coating level in comparison with uncoated seed. The resulting germination pattern was hypothetically explained by the dependence of water and oxygen uptake on temperature, in relation to the permeability of the coating materials. The permeability of the materials was probably rather constant over the temperature range. To gain the necessary control of the desired germination delay further investigations are needed, in collaboration with other scientific disciplines

Phenomenology and numerical analysis of the complex singlet extension of the Standard Model

The Standard model of particle physics has been very successful in describing particles and their interactions. In 2012 the last missing piece, the Higgs boson, was discovered at the Large Hadron Collider. However even for all its success the Standard model fails to explain some phenomena of nature. Two of these unexplained phenomena are dark matter and the metastability of the electroweak vacuum. In this thesis we study one of the simplest extensions of the Standard model; the complex singlet scalar extension. In this framework the CP-even component of the singlet mixes with the Standard model like Higgs boson through the portal operator to form new mass eigenstates. The CP-odd component is a pseudo-Goldstone boson which could be a viable dark matter candidate. We analyse parameter space of the model with respect to constraints from particle physics experiments and cosmological observations. The time evolution of dark matter number density is derived to study the process of dark matter freeze-out. The relic density of the Dark Matter candidate is then calculated with the micrOmegas tool. These calculations are then compared to the measured values of dark matter relic density. Moreover, the electroweak vacuum can be stabilised due the contribution of the singlet scalar to the Standard Model Higgs potential. We derive the β-functions of the couplings in order to study the renormalisation group evolution of the parameters of the model. With the contribution of the portal coupling to the β-function of the Higgs coupling we are able to stabilise the electroweak vacuum up to the Planck scale. The two-loop β-functions are calculated using the SARAH tool

Ministry Without Fear

I worry a lot about speaking to you senior seminarians. I feel honored and moved by the occasion. I sense much of the feelings and the fears and the joys and hopes, sometimes together and sometimes in clash, that are present in this room and in your branch of the church. It is the kind of situation in which it is difficult for anyone to speak who doesn\u27t have to pay the price of staying and sweating it out. I will not give a very delightful and happy dinner speech, although, I guess, real humor is not to tell stories but to know that ultimately things are in the hands of God and hence one should not get too serious about oneself, not even about oneself as a theologian or a pastor

The Bankruptcy-Law Safe Harbor for Derivatives: A Path-Dependence Analysis

U.S. bankruptcy law grants special rights and immunities to creditors in derivatives transactions, including virtually unlimited enforcement rights. This article argues that these rights and immunities result from a form of path dependence, a sequence of industry-lobbied legislative steps, each incremental and in turn serving as apparent justification for the next step, without a rigorous and systematic vetting of the consequences. Because the resulting “safe harbor” has not been fully vetted, its significance and utility should not be taken for granted; and thus regulators, legislators, and other policymakers—whether in the United States or abroad—should not automatically assume, based on its existence, that the safe harbor necessarily reflects the most appropriate treatment of derivatives transactions under bankruptcy and insolvency law or the treatment most likely to minimize systemic risk

Phagosome-lysosome fusion is a calcium-independent event in macrophages.

Phagosome-lysosome membrane fusion is a highly regulated event that is essential for intracellular killing of microorganisms. Functionally, it represents a form of polarized regulated secretion, which is classically dependent on increases in intracellular ionized calcium ([Ca2+]i). Indeed, increases in [Ca2+]i are essential for phagosome-granule (lysosome) fusion in neutrophils and for lysosomal fusion events that mediate host cell invasion by Trypanosoma cruzi trypomastigotes. Since several intracellular pathogens survive in macrophage phagosomes that do not fuse with lysosomes, we examined the regulation of phagosome-lysosome fusion in macrophages. Macrophages (M phi) were treated with 12.5 microM bis-(2-amino-S-methylphenoxy) ethane-N,N,N',N',-tetraacetic acid tetraacetoxymethyl ester (MAPT/AM), a cell-permeant calcium chelator which reduced resting cytoplasmic [Ca2+]; from 80 nM to < or = 20 nM and completely blocked increases in [Ca2+]i in response to multiple stimuli, even in the presence of extracellular calcium. Subsequently, M phi phagocytosed serum-opsonized zymosan, staphylococci, or Mycobacterium bovis. Microbes were enumerated by 4',6-diamidino-2-phenylindole, dihydrochloride (DAPI) staining, and phagosome-lysosome fusion was scored using both lysosome-associated membrane protein (LAMP-1) as a membrane marker and rhodamine dextran as a content marker for lysosomes. Confirmation of phagosome-lysosome fusion by electron microscopy validated the fluorescence microscopy findings. We found that phagosome-lysosome fusion in M phi occurs noramlly at very low [Ca2+]i (< or = 20 nM). Kinetic analysis showed that in M phi none of the steps leading from particle binding to eventual phagosome-lysosome fusion are regulated by [Ca2+]i in a rate-limiting way. Furthermore, confocal microscopy revealed no difference in the intensity of LAMP-1 immunofluorescence in phagolysosome membranes in calcium-buffered vs. control macrophages. We conclude that neither membrane recognition nor fusion events in the phagosomal pathway in macrophages are dependent on or regulated by calcium

Soil carbon and nitrogen contents in forest soils are related to soil texture in interaction with pH and metal cations

The aim of this study was to better understand how soil carbon (C) and nitrogen (N) contents and the C:N ratio are related to soil texture, pH, and exchangeable aluminum and calcium in forest soils.For this purpose, we studied 1992 temperate and boreal forest soils located all over Sweden. We measured organic C and N as well exchangeable aluminum, calcium, and pH in the organic layer and three depth increments in the mineral soil (down to 65 cm), and analyzed the relationship between element contents, soil texture, and soil pH as well as their interactions.Soil C concentration and the C:N ratio were negatively related to soil pH. The C concentration was on average 2.6 times higher in very acidic soils (pH 5.0, in the uppermost 10 cm of the mineral soil. In contrast, N varied much less with pH, particularly in the organic layer, but was related to soil texture. The N concentration was 2.3 times higher in clayey and fine silty soils than in sandy soils, while the C concentration was only 1.85 times higher in clayey and fine silty soils than in sandy soils (in the uppermost 10 cm). Differences in C and N concentrations between clayey and fine silty soils compared to sandy soils were largest in the class of soils with pH > 5.0 and smallest in the class of soils with pH <= 4.0. Furthermore, C and N concentrations were both positively correlated with the concentration of exchangeable aluminum in the mineral soil, and these correlations were stronger in coarse-textured than in fine-textured soils. In addition, the C concentration was positively correlated with the concentration of exchangeable calcium in the organic layer.In conclusion, our results show that C concentration varied much more strongly with pH than N concentration, likely due to effects of pH on microbial respiration. The N concentration was more strongly related to soil texture than the C concentration, which is very likely due to the high charge density of organic N, which gives organic N a high affinity to adsorb to mineral surfaces. Furthermore, exchangeable aluminum seems to play an important role in the sorptive stabilization of organic matter in the mineral soil

Carbon, nitrogen, and phosphorus stoichiometry of organic matter in Swedish forest soils and its relationship with climate, tree species, and soil texture

While the carbon (C) content of temperate and boreal forest soils is relatively well studied, much less is known about the ratios of C, nitrogen (N), and phosphorus (P) of the soil organic matter, as well as the abiotic and biotic factors that shape them. Therefore, the aim of this study was to explore carbon, nitrogen, and organic phosphorus (OP) contents and element ratios in temperate and boreal forest soils and their relationships with climate, dominant tree species, and soil texture. For this purpose, we studied 309 forest soils located all over Sweden between 56 and 68 degrees N. The soils are a representative subsample of Swedish forest soils with a stand age > 60 years that were sampled for the Swedish Forest Soil Inventory. We found that the N stock of the organic layer increased by a factor of 7.5 from -2.0 to 7.5 degrees C mean annual temperature (MAT), which is almost twice as much as the increase in the organic layer stock along the MAT gradient. The increase in the N stock went along with an increase in the N : P ratio of the organic layer by a factor of 2.1 from -2.0 to 7.5 degrees C MAT (R-2 = 0.36, p < 0.001). Forests dominated by pine had higher C : N ratios in the organic layer and mineral soil down to a depth of 65 cm than forests dominated by spruce. Further, also the C : P ratio was increased in the pine-dominated forests compared to forests dominated by other tree species in the organic layer, while the C : OP ratio in the mineral soil was not elevated in pine forests. C, N, and OP contents in the mineral soil were higher in fine-textured soils than in coarse-textured soils by a factor of 2.3, 3.5, and 4.6, respectively. Thus, the effect of texture was stronger on OP than on N and C likely because OP adsorbs very rigidly to mineral surfaces. Further, we found that the P and K concentrations of the organic layer were inversely related to the organic layer stock, while the N : P ratio was positively related to the organic layer stock. Taken together, the results show that the N : P ratio of the organic layer was most strongly related to MAT. Further, the C : N ratio was most strongly related to dominant tree species even in the mineral subsoil. In contrast, the C : P ratio was only affected by dominant tree species in the organic layer, but the C : OP ratio in the mineral soil was hardly affected by tree species due to the strong effect of soil texture on the OP concentration

Spatial patterns of nitrogen isotope ratios in forest soils are related to latitude and soil phosphorus concentration

The aim of this study was to identify the parameters that affect the nitrogen (N) isotope ratio (& delta;N-15) in soils of temperate and boreal forests. We measured the & delta;N-15 in 30 soil profiles of temperate and boreal forests in Sweden and analyzed the relationships between & delta;N-15 in the soils and soil chemical properties as well as site characteristics. In addition, we conducted a meta-analyses of & delta;N-15 in the organic layer of European forests. We identified two types of & delta;N-15 patterns; in type D soils, the & delta;N-15 in the mineral soil decreases with depth, whereas in type C soil, the & delta;N-15 in the soil profile is almost constant. Type D soils had a significantly higher & delta;N-15 in the organic layer and upper mineral soil than type C soils, which is likely due to N isotope fractionation by ectomycorrhizal fungi in the topsoil. Type D soils were found in boreal forests, but not in temperate forests. They had a significantly lower atmospheric N deposition rate than type C soils, by a factor of 2.3, and a significantly higher phosphorus (P) concentration of the organic layer than type C soils, by a factor of 1.5. We also found that the & delta;N-15 was negatively correlated with the N:P ratio of the organic layer (R-2 = 0.21, p < 0.001). Across Europe, the & delta;N-15 of the organic layer was positively correlated with latitude (R-2 = 0.58, p < 0.001), and negatively with mean annual temperature (R-2 = 0.52, p < 0.001) and atmospheric N deposition (R-2 = 0.42, p < 0.001). In conclusion, our results show that the & delta;N-15 of the organic layer and microbial N (re-)cycling in forest soils is positively related with latitude and the P concentration of the organic layer