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An alternative to the usual vierbein field in a (3 + 1)-dimensional (euclidean) space-time is proposed such that the internal index takes only three values and the external is a double: ea = −ea. In flat space-time this field reduces to the self-dual generalized Levi-Civita symbol a. Like the vierbein field, our field determines the metric field g uniquely. It can be viewed upon as the 'cube root' of the metric field. In euclidean space the internal symmetry group is SL(3). In Minkowski space, in a sense to be explained, the internal symmetry group is SU(3). The Einstein-Hilbert action takes an elegant form in terms of this new field.
The molecular composition of five brown coals from three different basins (Maestrazgo, Mequinenza and Rubielos) in Spain was investigated by flash pyrolysis-gas chromatography and flash pyrolysis-gas chromatography-mass spectrometry. In these techniques, the macromolecular material is thermally degraded in an inert atmosphere and the compounds formed are on-line separated, identified and quantified. This information provided insight into the macromolecular structure of the coals which was inaccesible by other means. The composition of the pyrolysates is described in detail with emphasis on the distributions and relative abundance of n-alkanes, n-1-alkanes, (alkyl)phenols, sulphur compounds [(alkyl)thiophenes and (alkyl)benzenes and (alkyl)naphthalenes. These compound classes represent the major pyrolysis products of the samples analyse...
It is argued that the so-called holographic principle will obstruct attempts to produce physically realistic models for the unification of general relativity with quantum mechanics, unless determinism in the latter is restored. The notion of time in GR is so different from the usual one in elementary particle physics that we believe that certain versions of hidden variable theories can -- and must -- be revived. A completely natural procedure is proposed, in which the dissipation of information plays an essential role. Unlike earlier attempts, it allows us to use strictly continuous and differentiable classical field theories as a starting point (although discrete variables, leading to fermionic degrees of freedom, are also welcome), and we show how an effective Hilbert space of quantum states naturally emerges when one attempts to des...
This paper connects two research areas: automatic tagging on the web and statistical keyphrase extraction. First, we analyze the quality of tags in a collaboratively created folksonomy using traditional evaluation techniques. Next, we demonstrate how documents can be tagged automatically with a state-of-the-art keyphrase extraction algorithm, and further improve performance in this new domain using a new algorithm, “Maui”, that utilizes semantic information extracted from Wikipedia. Maui outperforms existing approaches and extracts tags that are competitive with those assigned by the best performing human taggers.
This article examines 110 reported incidents from an online survey of 26 women from each of the eight universities in New Zealand. They responded to questions asking them to describe times when work and non-work situations have helped or hindered their advancement in university leadership roles. Five key themes, incorporating a range of factors, emerged as making a difference to advancement as leaders. These themes are: work relationships; university environment; invisible rules; proactivity; and personal circumstances. This research is part of the L-SHIP (Leadership - Supporting Higher Intent & Practice) project and has two main aims. First, to identify factors in universities that help and hinder women’s advancement as leaders, as reported by women; second, to provide useful evidence to underpin the development of programmes supporti...
We study the dynamics of the transition between the low- and high-firing states of the cortical slow oscillation by using intracellular recordings of the membrane potential from cortical neurons of rats. We investigate the evidence for a bistability in assemblies of cortical neurons playing a major role in the maintenance of this oscillation. We show that the trajectory of a typical transition takes an approximately exponential form, equivalent to the response of a resistor–capacitor circuit to a step-change in input. The time constant for the transition is negatively correlated with the membrane potential of the lowfiring state, and values are broadly equivalent to neural time constants measured elsewhere. Overall, the results do not strongly support the hypothesis of a bistability in cortical neurons; rather, they suggest the cortica...
Charles Peirce’s diagrammatic logic - the Existential Graphs - is presented as a tool for illuminating how we know necessity, in answer to Benacerraf’s famous challenge that most “semantics for mathematics” do not “fit an acceptable epistemology”. It is suggested that necessary reasoning is in essence a recognition that a certain structure has the structure that it has. This means that, contra Hume and his contemporary heirs, necessity is observable. One just needs to pay attention, not just to individual things but to how those things are related in larger structures, certain aspects of which force certain others to be a particular way.
Although in situ sediment capping is frequently used to reduce internal loading of contaminants and nutrients, post-application assessment rarely includes the potential undesirable short-term effects on plankton species composition. We hypothesised that a modified zeolite (Z2G1) application as a sediment capping agent in Lake Okaro, New Zealand, could cause significant undesirable shifts in species composition of both zooplankton and phytoplankton due to burial of resting stages or interference with feeding for the zooplankton. Alternatively, we predicted that the capping agent might have no effect due to, for example, the coarse grain size of the material (1–3 mm). We used multidimensional scaling (MDS) and analysis of similarity (ANOSIM) to identify any adverse effects of Z2G1 on zooplankton and phytoplankton species composition (i....
Bradykinin, a nonapeptide with vasodilatory and permeabilizing activity, is generated through the cleavage of high-M(r) ('high-molecular-weight') kininogen by kallikrein, and its generation is facilitated by plasmin. In the ascitic fluid of patients with cirrhosis, there is massive cleavage of high-M(r) kininogen and activation of fibrinolysis, but bradykinin has never been measured directly. In the ascitic fluid of 24 patients with cirrhosis, we measured bradykinin-(1-9)-nonapeptide levels by RIA after liquid-phase and subsequent HPLC extraction, and those of its catabolic product bradykininin-(1-5)-pentapeptide by ELISA after liquid-phase extraction. Cleaved high-M(r) kininogen, activated factor XII and plasmin-antiplasmin complexes were measured in ascitic fluid and plasma. Plasma renin activity (PRA) was also determined. As a contr...
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