Velocity-Dependent Forces in Atomic Force Microscopy Imaging of Lipid Films

We have imaged adsorbed fluid lipid bilayers by atomic force microscopy. The patches were formed by rupture of phospholipid vesicles onto magnesium fluoride. We show that the membrane patches are fluid but can be stably imaged at scan rates higher than 6 p d s . At lower scan rates the tip penetrates through the layer. The penetrating tip does not destroy the fluid patches, and the previous image can be restored after increasing the scanning velocity. The dynamic forces that possibly explain the effect are discussed

Stereospecificity of cinnamyl alcohol dehydrogenase and synthesis of stereospecifically labelled coniferyl alcohol

Using horse liver alcohol dehydrogenase, stereospecifically tritiated (R)- and (S)-(γ-3H)-coniferyl alcohol was synthesized. Using both of these substrates it was demonstrated that cinnamyl alcohol dehydrogenase from lignifying Forsythia tissue specifically removes the pro-R-hydrogen atom of coniferyl alcohol in the oxidation to the aldehyde. This also means that in the reverse reaction the A-hydrogen of NADPH is transferred to the Re-site of coniferyl aldehyde

A universal density slope - velocity anisotropy relation

One can solve the Jeans equation analytically for equilibrated dark matter structures, once given two pieces of input from numerical simulations. These inputs are 1) a connection between phase-space density and radius, and 2) a connection between velocity anisotropy and density slope, the \alpha-\beta relation. The first (phase-space density v.s. radius) has been analysed through several different simulations, however the second (\alpha-\beta relation) has not been quantified yet. We perform a large set of numerical experiments in order to quantify the slope and zero-point of the \alpha-\beta relation. When combined with the assumption of phase-space being a power-law in radius this allows us to conclude that equilibrated dark matter structures indeed have zero central velocity anisotropy, central density slope of \alpha_0 = -0.8, and outer anisotropy of approximately \beta_\infinity = 0.5.Comment: 4 pages, 1 figure, to appear in the XXIst IAP Colloquium "Mass Profiles and Shapes of Cosmological Structures", Paris 4-9 July 2005, France, (Eds.) G. Mamon, F. Combes, C. Deffayet, B. Fort, EAS Publications Serie

Environmentally sustainable houshold consumption: From aggregate environmental pressures to indicators for priority fields of action

During the UNCED conference in Rio de Janeiro 1992 unsustainable consumption and production patterns were identified as one of the key driving forces behind theunsustainable development of the world (Agenda 21, chapter 4). These consumption and production patterns are based on the European model of industrialisation, spread around the globe in the age of colonisation and brought toextremes by the upper-class of industrialised societies, in particular in the United States, but also in a number of countries in the South. Therefore, all states of theworld share the task of developing sustainable consumption and productionpatterns, while particular responsibility rests with the industrialised nations of Europe, North America and Japan. They, and the thriving but small rich elite in the transition countries and in the South, form a global consumer society, with shared products, lifestyles and aspirations. As it is essential to support the transition towards sustainable development byproviding the proper information in an operational manner, the UNCED conference has called for the development of suitable means of information, and in particular for the development of sustainability indicators applicable throughout the world (Agenda 21, chapter 40). The UNDESA set of indicators for changingconsumption and production patterns offers helpful advice in this regard but stilllacks the theoretical underpinning needed to consistently complete it by definingthe few still missing indicators.This paper undertakes to suggest such a methodology based on the environmental space concept. It derives a set of science based indicators from this approachwhich are easily applicable in everyday life and analyses the environmentalrelevance of the consumption clusters chosen for analysis as well as the relevanceof the phenomena characterised by the indicators suggested. As households arejust one actor in the field of consumption, a qualitative assessment of influences isperformed and the result depicting the key actors for each environmentallyrelevant consumption cluster is presented as an actor matrix. --

Detecting charge noise with a Josephson junction: A problem of thermal escape in presence of non-Gaussian fluctuations

Motivated by several experimental activities to detect charge noise produced by a mesoscopic conductor with a Josephson junction as on-chip detector, the switching rate out of its zero-voltage state is studied. This process is related to the fundamental problem of thermal escape in presence of non-Gaussian fluctuations. In the relevant case of weak higher than second order cumulants, an effective Fokker-Planck equation is derived, which is then used to obtain an explicit expression for the escape rate. Specific results for the rate asymmetry due to the third moment of current noise allow to analyse experimental data and to optimize detection circuits.Comment: 4 pages, 1 figure; minor typos corrected, some revisions in the tex

Sustainability indicators: A compass on the road towards sustainability

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