1,049 research outputs found
The Sudbury Structure (Ontario, Canada) and Vredefort Structure (South Africa): A comparison
Both the Sudbury Structure (SS) and the Witwatersrand Basin surrounding the Vredefort Structure (VS) host some of the most important base and precious metal deposits on earth. In both structures Precambrian igneous, sedimentary and volcanic rocks were affected by the structure forming process, either meteorite impact or endogenic explosion, or as some VS workers propose, by high strain tectonics. Besides these general features there are some geological and geophysical characteristics that are strikingly similar in both structures. There are, however, some obvious differences. Directly related to the structure forming processes are breccias in the footwall rocks of both structures. Pseudotachylite breccias occurring in both structures display great similarities. Chemical and physical characteristics of the pseudotachylites are similar in both structures. Both structures are characterized by overturned collar rocks, not evident everywhere around the SS. The VS is rimmed by an up or overturned collar of sediments and volcanics of the Witwatersrand, Ventersdorp and Transvaal Supergroups. Drilling information proved that the strata of the Witwatersrand Supergroup in the south of the VS are lying horizontally. Shockmetamorphic features such as planar microdeformations in rock forming minerals and shatter cones are present in both structures in the footwall rocks and in the SS also in the breccias of the OF. Both structures have large geophysical anomalies associated with them. In both structures the anomalies were interpreted as being caused by mafic-ultramafic complexes underlying the structures
First verbs : On the way to mini-paradigms
This 18th issue of ZAS-Papers in Linguistics consists of papers on the development of verb acquisition in 9 languages from the very early stages up to the onset of paradigm construction. Each of the 10 papers deals with first-Ianguage developmental processes in one or two children studied via longitudinal data. The languages involved are French, Spanish, Russian, Croatian, Lithuanien, Finnish, English and German. For German two different varieties are examined, one from Berlin and one from Vienna. All papers are based on presentations at the workshop 'Early verbs: On the way to mini-paradigms' held at the ZAS (Berlin) on the 30./31. of September 2000. This workshop brought to a close the first phase of cooperation between two projects on language acquisition which has started in October 1999:
a) the project on "Syntaktische Konsequenzen des Morphologieerwerbs" at the ZAS (Berlin) headed by Juergen Weissenborn and Ewald Lang, and financially supported by the Deutsche Forschungsgemeinschaft, and
b) the international "Crosslinguistic Project on Pre- and Protomorphology in Language Acquisition" coordinated by Wolfgang U. Dressler in behalf of the Austrian Academy of Sciences
The role of E+A and post-starburst galaxies – II. Spectral energy distributions and comparison with observations
‘The definitive version is available at www3.interscience.wiley.com '. Copyright Royal Astronomical Society. DOI: 10.1111/j.1365-2966.2009.15036.xIn a previous paper, we have shown that the classical definition of E+A galaxies excludes a significant number of post-starburst galaxies. We suggested that analysing broad-band spectral energy distributions (SEDs) is a more comprehensive method to select and distinguish post-starburst galaxies than the classical definition of measuring equivalent widths of (Hδ) and [O ii] lines. In this paper, we will carefully investigate this new method and evaluate it by comparing our model grid of post-starburst galaxies to observed E+A galaxies from the MORPHS catalogue. In the first part, we investigate the UV-optical-NIR (near-infrared) SEDs of a large variety in terms of progenitor galaxies, burst strengths and time-scales of post-starburst models and compare them to undisturbed spiral, S0 and E galaxies as well as to galaxies in their starburst phase. In the second part, we compare our post-starburst models with the observed E+A galaxies in terms of Lick indices, luminosities and colours. We then use the new method of comparing the model SEDs with SEDs of the observed E+A galaxies. We find that the post-starburst models can be distinguished from undisturbed spiral, S0 and E galaxies and galaxies in their starburst phase on the basis of their SEDs. It is even possible to distinguish most of the different post-starbursts by their SEDs. From the comparison with observations, we find that all observed E+A galaxies from the MORPHS catalogue can be matched by our models. However, only models with short decline time-scales for the star formation rate are possible scenarios for the observed E+A galaxies in agreement with our results from the first paper.Peer reviewe
On the Typology of Inflection Class Systems
Inflectional classes are a property of the ideal inflecting-fusional language type. Thus strongly inflecting languages have the most complex vertical and horizontal stratification of hierarchical tree structures. Weakly inflecting languages which also approach the ideal isolating type or languages which also approach the agglutinating type have much shallower structures. Such properties follow from principles of Natural Morphology and from the distinction of the descendent hierarchy of macroclasses, classes, subclasses, subsubclasses etc. and homogeneous microclasses. The main languages of illustration are Latin, Lithuanian, Russian, German, French, Finnish, Hungarian and Turkis
Temperature dependence of the primary electron transfer in photosynthetic reaction centers from Rhodobacter sphaeroides
The primary electron transfer (ET) in reaction centers (RC) of Rhodobacter sphaeroides is investigated as a function of temperature with femtosecond time resolution. For temperatures from 300 to 25 K the ET to the bacteriopheophytin is characterized by a biphasic time dependence. The two time constants of τ1=3.5±0.4 ps and τ2=1.2±0.3 ps at T=300 K decrease continously with temperature to values of τ1=1.4±0.3 ps and τ2=0.3±0.15 ps at 25 K. The experimental results indicate that the ET is not thermally activated and that the same ET mechanisms are active at room and low temperatures. All observations are readily rationalized by a two-step ET model with the monomeric bacteriochlorophyll as a real electron carrier
Viewing the efficiency of chaos control
This paper aims to cast some new light on controlling chaos using the OGY-
and the Zero-Spectral-Radius methods. In deriving those methods we use a
generalized procedure differing from the usual ones. This procedure allows us
to conveniently treat maps to be controlled bringing the orbit to both various
saddles and to sources with both real and complex eigenvalues. We demonstrate
the procedure and the subsequent control on a variety of maps. We evaluate the
control by examining the basins of attraction of the relevant controlled
systems graphically and in some cases analytically
Time-resolved spectroscopy of the primary photosynthetic processes of membrane-bound reaction centers from an antenna-deficient mutant of Rhodobacter capsulatus
The primary photosynthetic reactions in whole membranes of the antenna-deficient mutant strain U43 (pTXA6–10) of Rhodobacter capsulatus are studied by transient absorption and emission spectroscopy with subpicosecond time resolution. Extensive similarities between the transient absorption data on whole membranes and on isolated reaction centers support the idea that the primary processes in isolated reaction centers are not modified by the isolation procedure
On the Typology of Inflection Class Systems
Inflectional classes are a property of the ideal inflecting-fusional language type. Thus strongly inflecting languages have the most complex vertical and horizontal stratification of hierarchical tree structures. Weakly inflecting languages which also approach the ideal isolating type or languages which also approach the agglutinating type have much shallower structures. Such properties follow from principles of Natural Morphology and from the distinction of the descendent hierarchy of macroclasses, classes, subclasses, subsubclasses etc. and homogeneous microclasses. The main languages of illustration are Latin, Lithuanian, Russian, German, French, Finnish, Hungarian and Turkish
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