1,557 research outputs found

    Biodegradation of phenoxyacetic acid in soil by Pseudomonas putida PP0301(pR0103), a constitutive degrader of 2, 4–dichlorophenoxyacetate

    Full text link
    The efficacy of using genetically engineered microbes (GEMs) to degrade recalcitrant environmental toxicants was demonstrated by the application of Pseudomonas putida PP0301(pR0103) to an Oregon agricultural soil amended with 500 u.g/g of a model xenobiotic, phenoxyacetic acid (PAA). P. putida PP0301(pR0103) is a constitutive degrader of 2, 4–dichlorophenoxyacetate (2, 4–D) and is also active on the non–inducing substrate, PAA. PAA is the parental compound of 2, 4–dichlorophenoxyacetic acid (2, 4–D) and whilst the indigenous soil microbiota degraded 500 ng/g 2, 4–D to less than 10 J–g/g, PAA degradation was insignificant during a 40–day period. No significant degradation of PAA occurred in soil inoculated with the parental strain P. putida PP0301 or the inducible 2, 4–D degrader P. putida PP0301(pR0101). Moreover, co–amendment of soil with 2, 4–D and PAA induced the microbiota to degrade 2, 4–D; PAA was not degraded. P. putida PP0301–(pR0103) mineralized 500–Μg/g PAA to trace levels within 13 days and relieved phytotoxicity of PAA to Raphanus sativus (radish) seeds with 100% germination in the presence of the GEM and 7% germination in its absence. In unamended soil, survival of the plasmid–free parental strain P. putida PP0301 was similar to the survival of the GEM strain P. putida PP0301(pR0103). However, in PAA amended soil, survival of the parent strain was over 10 000–fold lower (< 3 colony forming units per gram of soil) than survival of the GEM strain after 39 days.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75471/1/j.1365-294X.1992.tb00160.x.pd

    Ligand‐induced donor state destabilisation – a new route to panchromatically absorbing cu(I) complexes

    Get PDF
    The intense absorption of light to covering a large part of the visible spectrum is highly desirable for solar energy conversion schemes. To this end, we have developed novel anionic bis(4 H ‐imidazolato)Cu(I) complexes (cuprates), which feature intense, panchromatic light absorption properties throughout the visible spectrum and into the NIR region with extinction coefficients up to 28,000 M −1  cm −1 . Steady‐state absorption, (spectro)electrochemical and theoretical investigations reveal low energy (Vis to NIR) metal‐to‐ligand charge‐transfer absorption bands, which are a consequence of destabilized copper‐based donor states. These high‐lying copper‐based states are induced by the σ‐donation of the chelating anionic ligands, which also feature low energy acceptor states. The optical properties are reflected in very low, copper‐based oxidation potentials and three ligand‐based reduction events. These electronic features reveal a new route to panchromatically absorbing Cu(I) complexes.Cu(I) and two chelating , anionic polymethine‐type ligands form a novel type of photoactive cuprate. The ligands induce the destabilisation of the Cu(I)‐based donor states and act themselves as acceptors. This leads to an unusually broad and intense absorption spectrum with metal‐to‐ligand charge‐transfer transitions from the visible to near‐infrared region. imag

    Ator e/ou animador a serviço da representação

    Get PDF
    Este artigo propÔe-se a identificar o espaço onde o ator e o manipulador se encontram no cumprimento de suas funçÔes ou contribuem e influenciam o trabalho do outro. Esta pesquisa surgiu do estudo de alguns artistas que através de um olhar sobre a expressividade dos bonecos/objetos no Teatro de Bonecos contribuiriam à reflexão da arte do ator. Portanto, pontuo alguns caminhos onde o ator e o animador agem de maneira próxima, procurando identificar características comuns que serviriam à representação no Teatro

    Pufendorf, Samuel

    Get PDF
    During the last two decades, Samuel von Pufendorf’s (1632–1694) natural law philosophy has become the subject of renewed and growing attentiveness among intellectual historians and philosophers (Seidler 2015). In the late-seventeenth century and early eighteenth century, Pufendorf was the most widely-read moral and political philosopher in Europe, whose reputation is most clearly exemplified in the impressive number of translations and editions of his works. Pufendorfian natural law theory offered a shared vocabulary and conceptual possibilities for the discussion of morality, politics and interstate relations for numerous eighteenth-century thinkers, such as Christian Thomasius, the authors of the Scottish Enlightenment and Jean-Jacques Rousseau. Pufendorf spent large parts of his career in princely courts and portrayed the history of states and their natural law foundations in his widely circulated historical works (Seidler 1997). Moreover, he also wrote on the issues of theology and church-state relations (Döring 1992, Zurbuchen 1998).Peer reviewe

    Vortex microavalanches in superconducting Pb thin films

    Full text link
    Local magnetization measurements on 100 nm type-II superconducting Pb thin films show that flux penetration changes qualitatively with temperature. Small flux jumps at the lowest temperatures gradually increase in size, then disappear near T = 0.7Tc. Comparison with other experiments suggests that the avalanches correspond to dendritic flux protrusions. Reproducibility of the first flux jumps in a decreasing magnetic field indicates a role for defect structure in determining avalanches. We also find a temperature-independent final magnetization after flux jumps, analogous to the angle of repose of a sandpile.Comment: 6 pages, 5 figure

    Maximal LpL^p-regularity for stochastic evolution equations

    Full text link
    We prove maximal LpL^p-regularity for the stochastic evolution equation \{{aligned} dU(t) + A U(t)\, dt& = F(t,U(t))\,dt + B(t,U(t))\,dW_H(t), \qquad t\in [0,T], U(0) & = u_0, {aligned}. under the assumption that AA is a sectorial operator with a bounded H∞H^\infty-calculus of angle less than 12π\frac12\pi on a space Lq(O,ÎŒ)L^q(\mathcal{O},\mu). The driving process WHW_H is a cylindrical Brownian motion in an abstract Hilbert space HH. For p∈(2,∞)p\in (2,\infty) and q∈[2,∞)q\in [2,\infty) and initial conditions u0u_0 in the real interpolation space \XAp we prove existence of unique strong solution with trajectories in L^p(0,T;\Dom(A))\cap C([0,T];\XAp), provided the non-linearities F:[0,T]\times \Dom(A)\to L^q(\mathcal{O},\mu) and B:[0,T]\times \Dom(A) \to \g(H,\Dom(A^{\frac12})) are of linear growth and Lipschitz continuous in their second variables with small enough Lipschitz constants. Extensions to the case where AA is an adapted operator-valued process are considered as well. Various applications to stochastic partial differential equations are worked out in detail. These include higher-order and time-dependent parabolic equations and the Navier-Stokes equation on a smooth bounded domain \OO\subseteq \R^d with d≄2d\ge 2. For the latter, the existence of a unique strong local solution with values in (H^{1,q}(\OO))^d is shown.Comment: Accepted for publication in SIAM Journal on Mathematical Analysi

    Greater sexual reproduction contributes to differences in demography of invasive plants and their noninvasive relatives

    Get PDF
    An understanding of the demographic processes contributing to invasions would improve our mechanistic understanding of the invasion process and improve the efficiency of prevention and control efforts. However, field comparisons of the demography of invasive and noninvasive species have not previously been conducted. We compared the in situ demography of 17 introduced plant species in St. Louis, Missouri, USA, to contrast the demographic patterns of invasive species with their less invasive relatives across a broad sample of angiosperms. Using herbarium records to estimate spread rates, we found higher maximum spread rates in the landscape for species classified a priori as invasive than for noninvasive introduced species, suggesting that expert classifications are an accurate reflection of invasion rate. Across 17 species, projected population growth was not significantly greater in invasive than in noninvasive introduced species. Among five taxonomic pairs of close relatives, however, four of the invasive species had higher projected population growth rates compared with their noninvasive relative. A Life Table Response Experiment suggested that the greater projected population growth rate of some invasive species relative to their noninvasive relatives was primarily a result of sexual reproduction. The greater sexual reproduction of invasive species is consistent with invaders having a life history strategy more reliant on fecundity than survival and is consistent with a large role of propagule pressure in invasion. Sexual reproduction is a key demographic correlate of invasiveness, suggesting that local processes influencing sexual reproduction, such as enemy escape, might be of general importance. However, the weak correlation of projected population growth with spread rates in the landscape suggests that regional processes, such as dispersal, may be equally important in determining invasion rate
    • 

    corecore