300 research outputs found

    Biological soil quality as a factor of efficient resource utilization in organic farming systems

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    In 1978 the DOK long-term field experiment was installed at Therwil close to Basel comparing the farming systems „bio-Dynamic“, „bio-Organic“ and „(K)conventional“. In the first years of the trial, crop yield and feasibility of organic farming were investigated. Soils were analysed with respect to long-term effects on fertility and were evaluated in the view of farming effects on the environment. Today the interrelation of diversity and efficiency and the quality of organic products is the research focus. Long-term trials like the DOK-trial offer unique opportunities for this kind of research. The DOK-trial compares the three systems mentioned above on the basis of the same intensity of organic fertilization (i.e. the same number of animals per area), the same crop rotation and the same soil tillage. Fertilization and plant protection are different and done according to the farming system. A minerally fertilized conventional treatment is mimicking stockless farming and unfertilized plots serve as controls. Crop yields of the organic systems averaged over 21 experimental years at 80% of the conventional ones. The fertilizer input, however, was 34 – 51% lower, indicating an efficient production. The organic farming systems used 20 – 56% less energy to produce a crop unit and per land area this difference was 36 – 53%. Maintenance of soil fertility is important for a sustainable land use. In DOK field plots the organically treated soils were biologically more active than conventional, whereas chemical and physical soil parameters differed less significantly. Soil organic matter after 21 years shows substantially higher values in farming systems with manure fertilization and especially in biodynamic field plots fertilized with composted farmyard manure. Organic farming systems are suggested to utilize non-renewable resources more efficiently due to a higher inherent soil fertility

    Mitigation and Adaptation Strategies – Organic Agriculture

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    This psoter presents information on the following - The concept of organic farming in the context of climate change - Carbon sequestration on organic farms - Consequences of an area-wide conversion to organic agricultur

    Immunological reactivity of a human immunodeficiency virus type I derived peptide representing a consensus sequence of the GP120 major neutralizing region V3

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    To reduce the opportunities for human immunodeficiency virus type 1 (HIV-1) to evade vaccine induced immunity, the development of subunit vaccines must focus on the characterization of immunogenic epitopes, which are major targets for the immune system. The most dominant site for elicitation of neutralising immune response is located on the external envelope glycoprotein gp120 within the third variable domain (V3). To overcome virus type specificity of antibodies directed to the V3-domain we designed a 36 amino acids long gp120/V3-consensus peptide (V3-C36) based on published biological data and sequence comparisons of various HIV-1 virus isolates. This peptide contains a conserved core sequence which is suggested to form a surface-exposed beta-turn. This peptide also includes T-cell epitopes defined in mice and humans, an ADCC-epitope and two highly conserved cysteine residues which were oxidized to form a cystine derivate, thus allowing correct peptide folding. In ELISA-tests, this peptide reacts with at least 90% of randomly selected sera of European and African patients infected with HIV-1 and is recognized by three different HIV-1/V3 "type-specific" antisera (MN, RF, IIIB-strain). Using this peptide as immunogen in rabbits, antisera could be raised with highly cross-reactive and HIV-1/IIIB strain neutralizing properties. Moreover, HTLV/HIV-1/IIIB specific cytotoxic T-lymphocytes (CTLs) of BALB/c mice infected with a gp120 recombinant vaccinia virus recognized the central 16- and 12-mer peptides of the V3-C36 consensus peptide in cytolytic assays, indicating perfect compatibility of the consensus peptide with the IIIB-primed CTLs. The DNA-sequence encoding the V3-consensus loop region might be an important component in newly designed recombinant subunit vaccines. In addition, due to its broad serological reactivity, the V3-consensus peptide might play an important role in special diagnostic purposes

    Carbon sequestration and stabilization in a 40-year agronomic long-term experiment

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    Soils contain more carbon (C) in the form of organic matter (soil organic matter = SOM) than the entire atmosphere and global vegetation put together. They are thus a central component of the global C cycle and its largest dynamic reservoir. On the one hand, intelligent agricultural practices are discussed as a way of mitigating climate change because they can increase the amount of SOM and thus actively remove C from the atmosphere. On the other hand, all intensively used soils lose C in the long term. Central questions in this context revolve around the extent and dynamics of storage, the stabilisation mechanisms involved and the impact of agricultural use on the C budget

    Studies on processing, particle formation, and immunogenicity of the HIV-1 gag gene product: a possible component of a HIV vaccine

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    Antigens in a particulate conformation were shown to be highly immunogenic in mammals. For this reason, the particle forming capacity of derivatives of the HIV-1 group specific core antigen p55 gag was assayed and compared dependent on various expression systems: recombinant bacteria, vaccinia- and baculoviruses were established encoding the entire core protein p55 either in its authentic sequence or lacking the myristylation consensus signal. Moreover, p55 gag was expressed in combination with the protease (p55-PR) or with the entire polymerase (p55-pol), respectively. Budding of 100-160 nm p55 core particles, resembling immature HIV-virions, was observed in the eucaryotic expression systems only. In comparison to the vaccinia virus driven expression of p55 in mammalian cells, considerably higher yields of particulate core antigen were obtained by infection of Spodoptera frugiperda (Sf9) insect cells with the recombinant Autographa californica nuclear polyhedrosis (AcMNPV) baculovirus. Mutation of the NH2-terminal myristylation signal sequence prevented budding of the immature core particles. Expression of the HIV p55-PR gene construct by recombinant baculovirus resulted in complete processing of the p55 gag precursor molecule in this system. The introduction of an artificial frameshift near the natural frameshift site resulted in constitutive expression of the viral protease and complete processing of p55, both in Escherichia coli and in vaccinia virus infected cells. Interestingly, significant processing of p55 resembling that of HIV infected H9 cells could also be achieved in the vaccinia system by fusing the entire pol gene to the gag gene. Moreover, processing was not found to be dependent on amino-terminal myristylation of the gag procursor molecule, which is in contrast to observations with type C and type D retrovirus. However, complete processing of p55 into p24, p17, p9 and p6 abolished particle formation. Purified immature HIV-virus like particles were highly immunogenic in rabbits, leading to a strong humoral immune response after immunization. Empty immature p55 gag particles represent a noninfectious and attractive candidate for a basic vaccine component

    The two-fluid model with superfluid entropy

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    The two-fluid model of liquid helium is generalized to the case that the superfluid fraction has a small entropy content. We present theoretical arguments in favour of such a small superfluid entropy. In the generalized two-fluid model various sound modes of He  \;II are investigated. In a superleak carrying a persistent current the superfluid entropy leads to a new sound mode which we call sixth sound. The relation between the sixth sound and the superfluid entropy is discussed in detail.Comment: 22 pages, latex, published in Nuovo Cimento 16 D (1994) 37

    Profiling soil microbial communities influenced by reduced summer precipitation and farming system history

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    Soil bacteria and fungi are the basis of soil food webs and contribute to a wide range of essential soil functions in arable lands. Intense land use and climate change induced reductions in summer precipitation can have varying influences on abundance, composition, and activity of microbial communities with largely unknown consequences for soil functions and plant growth including crop yields. The impact of altered precipitation patterns on soil biodiversity and associated ecosystem functions is on top of the list of eight major research gaps identified by an expert group for the European Commission still, this relationship is rarely studied under field conditions

    Change of biological soil quality in organic and conventional farming systems of the DOK trial

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    The DOK trial has started in the 1970ies, when first reports warned us on the consequences of our actions and the limits to growth. Even though farmers and a huge research community know better, we are still not managing our soils in a sustainable way. It seems inevitable that the mainstream agriculture wants to go beyond natural frontiers. Soils have an enormous buffering capacity, but this ends, when ecosystems are collapsing not only at the local, but also at the global level

    Fungal diversity within organic and conventional farming systems in Central Highlands of Kenya

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    Open Access Article; Published online: 30 June 2020Fungal diversity in agro-ecosystems is influenced by various factors related to soil and crop management practices. However, due to the complexity in fungal cultivation, only a limited number has been extensively studied. In this study, amplicon sequencing of the Internal Transcribed Spacer (ITS) region was used to explore their diversity and composition within long-term farming system comparison trials at Chuka and Thika in Kenya. Sequences were grouped into operational taxonomic units (OTUs) at 97% similarity and taxonomy assigned via BLASTn against UNITE ITS database and a curated database derived from GreenGenes, RDPII and NCBI. Statistical analyses were done using Vegan package in R. A total of 1,002,188 high quality sequences were obtained and assigned to 1,128 OTUs; they were further classified into eight phyla including Ascomycota, Basidiomycota, Chytridiomycota, Glomeromycota, Calcarisporiellomycota, Kickxellomycota, Mortierellomycota and unassigned fungal phyla. Ascomycota was abundant in conventional systems at Chuka site while Basidiomycota and Chytridiomycota were dominant in conventional systems in both sites. Kickxellomycota and Calcarisporiellomycota phyla were present in all organic systems in both sites. Conventional farming systems showed a higher species abundance and diversity compared to organic farming systems due to integration of organic and inorganic inputs

    Nominal or Real? The Impact of Regional Price Levels on Satisfaction with Life

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    According to economic theory, real income, i.e., nominal income adjusted for purchasing power, should be the relevant source of life satisfaction. Previous work, however, has only studied the impact of inflation adjusted nominal income and not taken into account regional differences in purchasing power. Therefore, we use a novel data set to study how regional price levels affect satisfaction with life. The data set comprises about 7 million data points that are used to construct a price level for each of the 428 administrative districts in Germany. We estimate pooled OLS and ordered probit models that include a comprehensive set of individual level, time-varying and time-invariant control variables as well as control variables that capture district heterogeneity other than the price level. Our results show that higher price levels significantly reduce life satisfaction. Furthermore, we find that a higher price level tends to induce a larger loss in life satisfaction than a corresponding decrease in nominal income. A formal test of neutrality of money, however, does not reject neutrality of money. Our results provide an argument in favor of regional indexation of government transfer payments such as social welfare benefits
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