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1.
Alexandra Sauer 《Systemic Practice and Action Research》2008,21(6):497-515
The participation of non-state actors in implementation processes is often understood as a means to increase compliance efficiency.
But the implementation of spatial policies frequently focuses on pre-established goals, processes and instruments and thus
renders difficult open discourse and shared decision-making. This paper introduces conflict pattern analysis (CPA) as a tool
that supports the analysis of the actual actor constellation in order to define efficient approaches that avoid common problems
of participatory processes. CPA is a semi-formalised method that helps to identify key-actors, their relations and interaction
amongst each other as well as their core beliefs, interests and resources. It aggregates this information to interaction patterns
that can be compared, classified and linked to different participatory methods on a theoretically informed basis. Particularly
on the local and regional level, this could be the first step for successful (participatory) implementation strategies. 相似文献
2.
Tilman Sauer 《Archive for History of Exact Sciences》2005,59(6):577-590
The history of the publication of the gravitational field equations of general relativity in November 1915 by Einstein and
Hilbert is briefly reviewed. An analysis of the internal structure and logic of Hilbert's theory as expounded in extant proofs
and in the published version of his relevant paper is given with respect to the specific question what information would have
been found on a missing piece of Hilbert's proofs. The existing texts suggest that the missing piece contained the explicit
form of the Riemann curvature scalar in terms of the Ricci tensor as a specification of the axiomatically underdetermined
Lagrangian in Hilbert's action integral. An alternative reading that the missing piece of the proofs already may have contained
the Einstein tensor, i.e. an explicit calculation of the gravitational part of Hilbert's Lagrangian is argued to be highly
implausible. 相似文献
3.
lambda Repressor and cro--components of an efficient molecular switch 总被引:48,自引:0,他引:48
In a lysogen, most genes of phage lambda are repressed; in response to a transient induction signal, they are efficiently switched on. The switch, which consists in part of a tripartite operator to which two regulatory proteins bind, depends not only on DNA--protein interactions, but also on effects transmitted from one DNA-bound protein to another. lambda Exemplifies a strategy that facilitates efficient switching between two physiological states in response to a transient signal. 相似文献
4.
Transcriptional control. Scissors and helical forks 总被引:2,自引:0,他引:2
5.
Tilman Sauer 《Archive for History of Exact Sciences》2008,62(1):1-22
Einstein’s early calculations of gravitational lensing, contained in a scratch notebook and dated to the spring of 1912, are
reexamined. A hitherto unknown letter by Einstein suggests that he entertained the idea of explaining the phenomenon of new
stars by gravitational lensing in the fall of 1915 much more seriously than was previously assumed. A reexamination of the
relevant calculations by Einstein shows that, indeed, at least some of them most likely date from early October 1915. But
in support of earlier historical interpretation of Einstein’s notes, it is argued that the appearance of Nova Geminorum 1912
(DN Gem) in March 1912 may, in fact, provide a relevant context and motivation for Einstein’s lensing calculations on the
occasion of his first meeting with Erwin Freundlich during a visit in Berlin in April 1912. We also comment on the significance
of Einstein’s consideration of gravitational lensing in the fall of 1915 for the reconstruction of Einstein’s final steps
in his path towards general relativity. 相似文献
6.
Qualitative theoretical approaches such as graph theory and stoichiometric analyses are beginning to uncover the architecture and systemic functions of complex metabolic reaction networks. At present, however, only a few, largely unproven quantitative concepts propose functional design principles of the global flux distribution. As operational units of function, molecular fluxes determine the systemic cell phenotype by linking genes, proteins and metabolites to higher-level biological functions. In sharp contrast to other 'omics' analyses, 'fluxome' analysis remained tedious. By large-scale quantification of in vivo flux responses, we identified a robust flux distribution in 137 null mutants of Bacillus subtilis. On its preferred substrate, B. subtilis has suboptimal metabolism because regulators of developmental programs maintain a 'standby' mode that invests substantial resources in anticipation of changing environmental conditions at the expense of optimal growth. Network rigidity and robustness are probably universal functional design principles, whereas the standby mode may be more specific. 相似文献
7.
Hexameric ring-shaped ATPases of the AAA + (for ATPases associated with various cellular activities) superfamily power cellular processes in which macromolecular structures and complexes are dismantled or denatured, but the mechanisms used by these machine-like enzymes are poorly understood. By covalently linking active and inactive subunits of the ATPase ClpX to form hexamers, here we show that diverse geometric arrangements can support the enzymatic unfolding of protein substrates and translocation of the denatured polypeptide into the ClpP peptidase for degradation. These studies indicate that the ClpX power stroke is generated by ATP hydrolysis in a single subunit, rule out concerted and strict sequential ATP hydrolysis models, and provide evidence for a probabilistic sequence of nucleotide hydrolysis. This mechanism would allow any ClpX subunit in contact with a translocating polypeptide to hydrolyse ATP to drive substrate spooling into ClpP, and would prevent stalling if one subunit failed to bind or hydrolyse ATP. Energy-dependent machines with highly diverse quaternary architectures and molecular functions could operate by similar asymmetric mechanisms. 相似文献
8.
9.
Mazzali PA Deng J Nomoto K Sauer DN Pian E Tominaga N Tanaka M Maeda K Filippenko AV 《Nature》2006,442(7106):1018-1020
Supernovae connected with long-duration gamma-ray bursts (GRBs) are hyper-energetic explosions resulting from the collapse of very massive stars ( approximately 40 M\circ, where M\circ is the mass of the Sun) stripped of their outer hydrogen and helium envelopes. A very massive progenitor, collapsing to a black hole, was thought to be a requirement for the launch of a GRB. Here we report the results of modelling the spectra and light curve of SN 2006aj (ref. 9), which demonstrate that the supernova had a much smaller explosion energy and ejected much less mass than the other GRB-supernovae, suggesting that it was produced by a star whose initial mass was only approximately 20 M\circ. A star of this mass is expected to form a neutron star rather than a black hole when its core collapses. The smaller explosion energy of SN 2006aj is matched by the weakness and softness of GRB 060218 (an X-ray flash), and the weakness of the radio flux of the supernova. Our results indicate that the supernova-GRB connection extends to a much broader range of stellar masses than previously thought, possibly involving different physical mechanisms: a 'collapsar' (ref. 8) for the more massive stars collapsing to a black hole, and magnetic activity of the nascent neutron star for the less massive stars. 相似文献
10.
Friml J Vieten A Sauer M Weijers D Schwarz H Hamann T Offringa R Jürgens G 《Nature》2003,426(6963):147-153
Axis formation occurs in plants, as in animals, during early embryogenesis. However, the underlying mechanism is not known. Here we show that the first manifestation of the apical-basal axis in plants, the asymmetric division of the zygote, produces a basal cell that transports and an apical cell that responds to the signalling molecule auxin. This apical-basal auxin activity gradient triggers the specification of apical embryo structures and is actively maintained by a novel component of auxin efflux, PIN7, which is located apically in the basal cell. Later, the developmentally regulated reversal of PIN7 and onset of PIN1 polar localization reorganize the auxin gradient for specification of the basal root pole. An analysis of pin quadruple mutants identifies PIN-dependent transport as an essential part of the mechanism for embryo axis formation. Our results indicate how the establishment of cell polarity, polar auxin efflux and local auxin response result in apical-basal axis formation of the embryo, and thus determine the axiality of the adult plant. 相似文献