1,354,556 research outputs found
Palaeotectonic and palaeogeographic evolution of the western Tethys and PeriTethyan domain (IGCP Project 369)
No full textProject No. 369 ("Comparative Evolution of PeriTethyan Rift Basins") of the International Geological Correlation Program produced a new palaeotectonic-palaeogeographic atlas of the western PeriTethyan domain. The atlas contains more than two hundred new maps and documents grouped in nine regional sets (Iberia, Polish Trough, Eastern European and Scythian Platforms, Moesian Platform, Levant, Arabian Platform, Northern Africa, NE Africa-NW Arabia, Libya-Pelagian Shelf) plus a set of reconstructions for the whole western Tethys. The area considered in the atlas stretches, from west to east, from the eastern Atlantic shores to the Urals and, from north to south, from the Baltic shield to equatorial Africa; the time span covered extends from the Late Carboniferous to the Present. The dataset, resulting from an extensive cooperation between industrial and academic sources, is accessible interactively on a CD-ROM (Stampfli et al., 2001a) and includes legend, timetable, short explanatory notes, full references and additional supporting data. This dataset provides information on the development of the Tethyan realm in space and time. In particular, the relation between the Variscan and Cimmerian cycles in the Mediterranean realm is illustrated by numerous palaeogeographic and palaeotectonic maps
Soleil de la Conscience, quand les images viatiques donnent à voir la pensée de la relation
No full textAnaïs STAMPFLI, Professeure à l'université des Antilles, explique la forme et le contenu de l'une des oeuvres de Glissant « Soleil de la Conscience ». Celle-ci constitue le premier essai poétique de Glissant, écrit lors de son séjour à Paris dans le cadre de ses études supérieures. L'intervenante propose d'observer comment ce séjour parisien a permis à l'auteur d'entrer en écriture et d'étudier son expérience personnelle de la mise en relation des univers antillais et parisiens, lesquels univers sont au centre de l'essai
Did recent climatic shifts affect productivity of grass-dominated vegetation in southern Switzerland? Evidence from time series of two semi-natural grasslands and a maize field
No full textTime series of crop data from three grass-dominated ecosystems in southern Switzerland were selected for a comparison with climatic variables over the past decades. Standing crop from two permanent species-rich grasslands at Prugiasco and Salorino and the kernel yield of maize planted every year in monoculture at Cadenazzo were measured using standardised methods under controlled conditions in experimental areas over 13 (1988-2000) or 28 (1972-1999) years, respectively. The maize series was corrected for effects of sowing density and genetic variation due to the change of varieties over time. The sensitivity of crop variables to climatic variables, temperature, precipitation, relative humidity and duration of sunshine, recorded at Locarno-Monti, was calculated for 3-month and half-year intervals in 1-yr periods previous to harvest dates. Yields in semi-natural grasslands and in the maize field significantly responded to climatic variables, which were not subject to long-term trends, relative humidity or sunshine, respectively, during the growth period. A series of extremely dry summers negatively affected yields of the maize field and triggered a lagged shift towards a reduced grass-forb ratio in the harvest of the more intensively mown meadow. Dry summers were explained by a lee-effect of upper-level winds blowing from a more northward direction over the Alps in 1989-1991. It is concluded that grass-dominated vegetation in the Southern Alps was more sensitive to changing precipitation patterns than increased temperatures. The vegetation response to climate depended on the methods of human interference
Zoological researches in Liberia. A list of Birds, collected by the Author and Mr. F. X. Stampfli during their last sojourn in Liberia
No full textAs I told in my previous paper on Liberian Ornithology ¹), Mr. Stampfli and I left for Liberia at the end of October 1886, and arrived at Monrovia, after short stays at Hamburg, Madeira, Teneriffa, Gran Canaria and the Senegal, on the 26th of November.
The next day I proceeded in an open sailing boat to Grand Cape Mount to get the servants, which were already hired for me by Mr. Watson, the Liberian Superintendent at Robertsport. From this latter place I visited some of my former stations on the Fisherman Lake, the Japaca Creek and on the Mahfa River.²) Everywhere I was very kindly received by the natives, who had not yet forgotten me and were much enjoyed to see me again. About medio December I returned with three Yey-boys and my old Liberian huntsman Jackson Demery to Monrovia and prepared for my removal to Schieffelinsville on the Junk River, where Mr. Stampfli meanwhile had hired a small Liberian farming house. As our outfit was very voluminous, I went to Schieffelinsville by sea with two sailing boats, entered near Marshall (a small Liberian settlement) the Junk River and reached, along this river, safely the place of my destination
Contributions to automorphisms of affine spaces
No full textWe study aspects of the group G_n of polynomial automorphisms of the affine space A^n, the so-called affine Cremona group. Shafarevich introduced on G_n the structure of an ind-variety, an infinite-dimensional analogon to a (classical) variety. The aim of this thesis is to study G_n within the framework of ind-varieties. The thesis consists of five articles. In the following we summarize them.
1. On the Topologies on ind-Varieties and related Irreducibility Questions.
In the literature there are two ways of endowing an affine ind-variety with a topology. One possibility is due to Shafarevich and the other due to Kambayashi. We specify a large class of affine ind-varieties where these two topologies differ. We give an example of an affine ind-variety that is reducible with respect to Shafarevich’s topology, but irreducible with respect to Kambayashi’s topology. Moreover, we give a counter-example of a supposed irreducibility criterion given by Shafarevich which is different from a counter-example given by Homma. We finish the article with an irreducibility criterion similar to the one given by Shafarevich.
2. On Automorphisms of the Affine Cremona Group (joint with Hanspeter Kraft)
We show that every automorphism of the group G_n is inner up to field automorphisms when restricted to the subgroup TG_n of tame automorphisms. This generalizes a result of Julie Déserti who proved this in dimension n = 2 where all automorphisms are tame, i.e. TG_2 = G_2. The methods are different, based on arguments from algebraic group actions.
3. A Note on Automorphisms of the Affine Cremona Group
Let G be an ind-group and let U be a unipotent ind-subgroup. We prove that an abstract automorphism f: G -> G maps U isomorphically onto a unipotent ind-subgroup of G, provided that f fixes a closed torus T in G that normalizes U and the action of T on U by conjugation fixes only the neutral element. As an application we generalize the main result of the article "On Automorphisms of the Affine Cremona Group" as follows: If an abstract automorphism of G_3 fixes the subgroup of tame automorphisms TG_3, then it also fixes a whole family of non-tame automorphisms (including the Nagata automorphism).
4. Automorphisms of the Plane Preserving a Curve (joint with Jérémy Blanc)
We study the group of automorphisms of the affine plane preserving some given curve, over any field. The group is proven to be algebraic, except in the case where the curve is a bunch of parallel lines. Moreover, a classification of the groups of positive dimension occuring is also given in the case where the curve is geometrically irreducible and the field is perfect.
5. Centralizer of a Unipotent Automorphism in the Affine Cremona Group
Let g be a unipotent element of G_3. We describe the centralizer Cent(g) inside G_3. First, we treat the case when g is a modified translation. In the other case, we describe the subset Cent(g)_u of unipotent elements of Cent(g) and prove that it is a closed normal subgroup of Cent(g). Moreover, we show that Cent(g) is the semi-direct product of Cent(g)_u with a closed algebraic subgroup R of Cent(g). Finally, we prove that the subgroup of Cent(g) consisting of those elements that induce the identity on the algebraic quotient Spec O(A^3)^g form a characteristic subgroup of Cent(g)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Zoological researches in Liberia. A list of Birds, collected by Mr. F. X. Stampfli near Monrovia, on the Messurado River, and on the Junk River with its tributaries
No full textIn my previous paper on Liberian Birds 1) I have already called attention to Mr. Stampfli, whom I enabled to carry on my zoological investigations after my return from Liberia. Mr. Stampfli, from July 1884 to April 1886, on different times had his headquarters at Paynesville and Oldfield, on the banks of the Messurado River about 15 sea-miles above Monrovia, and at Schieffelinsville on the Junk River, about 3 miles (in straight line) from the coast. From this latter place he explored not only the large Junk River, but also some of its tributaries, the Too- and the Du Queah River, which latter is about as large as the Junk River itself. Some of his specimens he collected in the vicinity of Monrovia, during several longer and shorter stays he had in this place. Mr. Stampfli most zealeously braved all the disagreeablenesses of a collectors life in that unhealthy country, until he got weakened in such a degree by repeated heavy attacks of malaria, that he was obliged to return to Europe in order to restore his health. Nevertheless the zoological explorations of that interesting country will not he stopped, as we both are decided to return together to Liberia at the end of October next. For that purpose I have got leave for a half years stay in Liberia, and after my return to Europe Mr. Stampfli will carry on the work alone. To all Zoologists, especially to Ornithologists, I should be thankful for every hint they would kindly give me with regard to the interesting fauna of Liberia, before my departure from Europe. Especially Anatomists would do well to call my attention to every wished for interesting species, which I readily will preserve in spirits as far as they can be obtained.
As our first stay will be on the banks of the Junk River, I after my return shall better be able than now to give a short sketch of that country
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