Technical University of Berlin

About: Technical University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Quantum dot & Laser. The organization has 27292 authors who have published 59342 publications receiving 1414623 citations. The organization is also known as: Technische Universität Berlin & TU Berlin.

Mapping ecosystem services' values: current practice and future prospects.

Abstract: Mapping of ecosystem services’ (ESS) values means valuing ESS in monetary terms across a relatively large geographical area and assessing how values vary across space. Thereby, mapping of ESS values reveals additional information as compared to traditional site-specific ESS valuation, which is beneficial for designing land use policies for maintaining ESS supply. Since the well-known article by Costanza et al. (1997), who mapped global ESS values, the number of publications mapping ESS values has grown exponentially, with almost 60% being published after 2007. Within this paper, we analyse and review articles that map ESS values. Our findings show that methodologies, in particular how spatial variations of ESS values are estimated, their spatial scope, rational and ESS focus differ widely. Still, most case studies rely on relatively simplistic approaches using land use/cover data as a proxy for ESS supply and its values. However, a tendency exists towards more sophisticated methodologies using the ESS models and value functions, which integrate a variety of spatial variables and which are validated against primary data. Based on our findings, we identify current practices and developments in the mapping of EES values and provide guidelines and recommendations for future applications and research.

Antimycoplasma properties and application in cell culture of surfactin, a lipopeptide antibiotic from Bacillus subtilis.

Abstract: Surfactin, a cyclic lipopeptide antibiotic and biosurfactant produced by Bacillus subtilis, is well-known for its interactions with artificial and biomembrane systems (e.g., bacterial protoplasts or enveloped viruses). To assess the applicability of this antiviral and antibacterial drug, we determined the cytotoxicity of surfactin with a 50% cytotoxic concentration of 30 to 64 microM for a variety of human and animal cell lines in vitro. Concomitantly, we observed an improvement in proliferation rates and changes in the morphology of mycoplasma-contaminated mammalian cells after treatment with this drug. A single treatment over one passage led to complete removal of viable Mycoplasma hyorhinis cells from various adherent cell lines, and Mycoplasma orale was removed from nonadherent human T-lymphoid cell lines by double treatment. This effect was monitored by a DNA fluorescence test, an enzyme-linked immunosorbent assay, and two different PCR methods. Disintegration of the mycoplasma membranes as observed by electron microscopy indicated the mode of action of surfactin. Disintegration is obviously due to a physicochemical interaction of the membrane-active surfactant with the outer part of the lipid membrane bilayer, which causes permeability changes and at higher concentrations leads finally to disintegration of the mycoplasma membrane system by a detergent effect. The low cytotoxicity of surfactin for mammalian cells permits specific inactivation of mycoplasmas without significant deleterious effects on cell metabolism and the proliferation rate in cell culture. These results were used to develop a fast and simple method for complete and permanent inactivation of mycoplasmas in mammalian monolayer and suspension cell cultures.

Determination of Chemical and Physical Soil Properties

Abstract: Objectives. Measures of soil water content and dry mass are needed in practically all types of soil studies, e.g., determination of water holding capacity, plant available water, infiltration, pore size distribution, permeability. With respect to soil microbial processes and biological soil remediation, determination of optimum water content for measurement of microbial parameters and activity, as well as determination of soil permeability for estimation of the success of in situ remediation, is of essential importance. Principle. Soil samples are dried at 105 ± 5 ◦C until mass constancy is reached. The differences in masses before and after drying are a measure for the water content of soils. The water content is calculated on gravimetric (gwater /gsoil) or on volumetric basis (cmwater/cmsoil). The method described below can be used for disturbed and undisturbed (sampling of soil using coring sieves) soil samples. It is a direct laboratory measurement. The procedure described can be used for the determination of dry mass on a mass basis (ISO 11465 1993).

Deterministic single exponential time algorithms for connectivity problems parameterized by treewidth

Abstract: It is well known that many local graph problems, like Vertex Cover?and Dominating Set, can be solved in time 2 O ( tw ) | V | O ( 1 ) for graphs G = ( V , E ) with a given tree decomposition of width tw. However, for nonlocal problems, like the fundamental class of connectivity problems, for a long time we did not know how to do this faster than tw O ( tw ) | V | O ( 1 ) . Recently, Cygan et al.?(FOCS 2011) presented Monte Carlo algorithms for a wide range of connectivity problems running in time c tw | V | O ( 1 ) for a small constant c, e.g., for Hamiltonian Cycle?and Steiner Tree. Naturally, this raises the question whether randomization is necessary to achieve this runtime; furthermore, it is desirable to also solve counting and weighted versions (the latter without incurring a pseudo-polynomial cost in the runtime in terms of the weights).We present two new approaches rooted in linear algebra, based on matrix rank and determinants, which provide deterministic c tw | V | O ( 1 ) time algorithms, also for weighted and counting versions. For example, in this time we can solve Traveling Salesman? or count the number of Hamiltonian cycles. The rank based ideas provide a rather general approach for speeding up even straightforward dynamic programming formulations by identifying "small" sets of representative partial solutions; we focus on the case of expressing connectivity via sets of partitions, but the essential ideas should have further applications. The determinant-based approach uses the Matrix Tree Theorem for deriving closed formulas for counting versions of connectivity problems; we show how to evaluate those formulas via dynamic programming.