76 research outputs found
Signature of a non-harmonic potential as revealed from a consistent shape and fluctuation analysis of an adherent membrane
The interaction of fluid membranes with a scaffold, which can be a planar
surface or a more complex structure, is intrinsic to a number of systems - from
artificial supported bilayers and vesicles to cellular membranes. In principle,
these interactions can be either discrete and protein mediated, or continuous.
In the latter case, they emerge from ubiquitous intrinsic surface interaction
potentials as well as nature-designed steric contributions of the fluctuating
membrane or from the polymers of the glycocalyx. Despite the fact that these
nonspecific potentials are omnipresent, their description has been a major
challenge from experimental and theoretical points of view. Here we show that a
full understanding of the implications of the continuous interactions can be
achieved only by expanding the standard superposition models commonly used to
treat these types of systems, beyond the usual harmonic level of description.
Supported by this expanded theoretical framework, we present three independent,
yet mutually consistent, experimental approaches to measure the interaction
potential strength and the membrane tension. Upon explicitly taking into
account the nature of shot noise as well as of finite experimental resolution,
excellent agreement with the augmented theory is obtained, which finally
provides a coherent view of the behavior of the membrane in a vicinity of a
scaffold.Comment: 15 pages, 12 figures, accepted by Physical Review
Probing molecular free energy landscapes by periodic loading
Single molecule pulling experiments provide information about interactions in
biomolecules that cannot be obtained by any other method. However, the
reconstruction of the molecule's free energy profile from the experimental data
is still a challenge, in particular for the unstable barrier regions. We
propose a new method for obtaining the full profile by introducing a periodic
ramp and using Jarzynski's identity for obtaining equilibrium quantities from
non-equilibrium data. Our simulated experiments show that this method delivers
significant more accurate data than previous methods, under the constraint of
equal experimental effort.Comment: 4 pages, 3 figure
Fat-tailed sheep in Indonesia; an essential resource for smallholders
This paper discusses the historical development of fat-tailed sheep in Indonesia, the dynamics of production systems, production and reproduction performances under farmers’ conditions, and roles of sheep in livelihoods. In the eighteenth and nineteenth century, fat-tailed sheep from southwest Asia and Africander sheep from South Africa were introduced. Crossing of fat-tailed sheep with the local thin-tailed sheep produced the Javanese fat-tailed sheep. Main motives for the gradual change-over to fat-tailed sheep have been their potential larger body size and the preference of consumers for their meat. Management systems are changing in response to the intensification of land use. The reproductive performances of fat-tailed sheep are good. Households keep four to six animals, housed close to the family quarters. This results in very high levels of faecal bacteria contamination of drinking water sources. Sheep provide a small income, manure, security and help to accumulate capital. Sheep also play a key role in religious festivities. Farmers hardly profit from the increased demand for the feast of sacrifice; animals are sold mainly when the owners have urgent cash needs. Systematic sheep fattening can contribute to higher economic results, if sufficient family labour and crop residues are available
Sport and physical culture in North Korea: resisting, recognizing and relishing globalization
The politics of sport diplomacy and reunification in divided Korea: one nation, two countries and three flags
North Korean media accounts of the Olympic and Asian Games: the fatherland's friends and foes
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