Refine
Year of publication
Document Type
- Article (31477) (remove)
Language
- English (16082)
- German (13387)
- Portuguese (696)
- French (387)
- Croatian (251)
- Spanish (250)
- Italian (134)
- Turkish (113)
- Multiple languages (36)
- Latin (35)
Has Fulltext
- yes (31477)
Keywords
- Deutsch (503)
- taxonomy (451)
- Literatur (299)
- new species (194)
- Hofmannsthal, Hugo von (185)
- Rezeption (178)
- Übersetzung (163)
- Filmmusik (155)
- Johann Wolfgang von Goethe (131)
- Vormärz (117)
Institute
- Medizin (5409)
- Physik (1959)
- Biowissenschaften (1152)
- Biochemie und Chemie (1113)
- Extern (1108)
- Gesellschaftswissenschaften (803)
- Frankfurt Institute for Advanced Studies (FIAS) (753)
- Geowissenschaften (593)
- Präsidium (453)
- Philosophie (448)
La coupure que l'on constate dans les forêts denses africaines au niveau du Togo et du Bénin soulève de nombreuses questions sur les rapports forêt/savane au cours des derniers millénaires. Le projet Dahomey Gap vise à y répondre, par une approche pluridisciplinaire intégrant botanique et histoire de la végétation dans le Sud-Bénin et le Sud-Ouest du Nigéria. A partir de travaux déjà avancés sur la végétation du Bénin et des premières prospections palynologiques, quelques aspects du projet sont exposés ici: tels la caractérisation des différentes formations forestières du Bénin, les premiers résultats sur l'histoire holocène de la végétation du Sud-Bénin (mangroves, forêts, savanes) enregistrée depuis près de 7000 ans dans les lagunes.
In a previous study which originally tackled the apparent contradiction between oral tradition and linguistic evidence in the Babur-Bura case, we approached the issue through a contrastive analysis of Bura and Kanuri. Since the originstory tends to push the Babur towards the Kanuri, leaving the Bura to stand all alone, it was felt that any linguistic closeness between Kanuri and Babur would confirm the originstory. Unfortunately, the paper did not come up with such evidence. The paper in question summarizes COHEN's (1983) account and interpretation of both the Babur and the Bura versions of their origin. It then presents the loopholes in the various accounts, based not only on the current linguistic classification of the area, but also on the results of an investigation carried out within the framework of the "Borno Surname Project". At both the phonological and syntactic levels, BADEJO (1989) observes that in view of certain fundamental differences between Kanuri on the one hand and Babur-Bura on the other, Babur affiliation with Kanuri is doubtful. Such differences include: the lack of voice distinction between the labiodental fricatives in Kanuri (i.e. /f/ and /v/; the /p/ - /f/ alternation), especially in wordinitial position in Kanuri, and finally, the SOV structure of the Kanuri sentence. The paper, drawing on support from an opinion survey, therefore concludes that "general linguistic and the social linguistic considerations presented ... seem to point to the fact that the Babur and the Bura are, by and large, the same people". The paper, however, recognizes the need for a Babur-Bura contrastive study. The current paper is the first step in that direction.
Le SIG-BF est destiné comme outil pour la visualisation et l’analyse des informations spatiales pour les scientifiques du «SFB 268 – Histoire des cultures et des langues dans l’espace naturel de la Savane Africaine» à l‘Institut Géographie Physique de la Johann Wolfgang Goethe-Universität à Frankfurt am Main et leurs collèges de l’Université de Ouagadougou. En outre, les données peuvent être utilisées par d'autres dans un but scientifique. La copie et la diffusion des données sont permises si la source est clairement mentionnée. L’usage professionnel et le traitement des données du SIG-BF dans un but commercial, soit sous forme imprimée ou sous forme digitale, nécessite la permission écrite de l’Institut Géographie Physique de l’Université Francfort. Les données spatiales qui sont assorties dans le BF-SIG sont basées sur plusieurs sources. En général, il y sont groupées des informations de l’environnement naturel et anthropique à l’échelle nationale de Burkina Faso. En majorité ce sont les données des cartes topographiques et thématiques du pays et quelques données statistiques. La connaissance des paramètres (p. ex. échelle, age, projection) des sources des données est une condition importante pour l'évaluation du degrée d'exactitude des résultats des analyses SIG. Quant à ca, quelques notes importantes sont démontrées dans la 2ième chapitre de ce texte. Les sources indiquées dans la table de matières (3ième chapitre) sous la forme des ‘numéro de la source’ sont précisées dans la 4ième chapitre.
Au nord du Burkina Faso aucune autre époque culturelle, à l'exception des temps modernes, n'a laissé autant de traces sur une aussi grande surface que l’Age de Fer. L'étude de cette période joue alors un rôle important dans la reconstruction de l'histoire culturelle du Sahel. D’après les dates obtenues dans nos fouilles différentes, l’Age de Fer s'étend de la fin du premier millénaire BC jusqu'au milieu du 14e siècle AD. Les recherches du projet multidisciplinaire G4 du SFB 268 visaient les questions suivantes: Quelle est l’apparence physique des collines d’occupation et quelle est leur répartition dans la région ? En quoi consiste la culture matérielle trouvée sur les sites et qu’est-ce qu’elle permet de dire sur la vie quotidienne? Comment l’interaction entre l'homme et l'environnement se présentaitelle à l’époque et quelles étaient les ressources naturelles exploitées? Quelle population occupait les buttes, et quels indices l’étude de l’histoire du peuplement peut fournir comme causes de leur abandon final? Le vaste champs d’études ouvert par ces questions impose une approche multidisciplinaire. Les résultats qui seront présentés cidessous n'ont pu être obtenus qu'en coopération de l'archéologie, l'archéobotanique, l'archéozoologie, l'histoire et la géographie.
In a recent article dealing with the Tangale Peak or Kilang, as it is called in the local Tangale language, Herrmann JUNGRAITHMAYR presents an account narrated by a Tangale elder about the attempted ascent of that characteristic mountain by a British colonial officer and his subsequent death.1 Kilang mountain is a basaltic cone approximately 1300 m high, about 8 km southwest of Kaltungo, one of the principal settlements of the Tangale people, in southern Bauchi State, northeastern Nigeria. During a research stay at the National Archives in Kaduna in November 1993 I was able to consult a file containing various documents relating to this incident in detail.2 In the following note I present an outline of the events based on the evidence in the colonial records. By doing this I not only intend to shed more light on a tragic event from the very early years of the colonial era. The picture of the circumstances emerging from the investigations of the colonial authorities may serve as a background to the narrative by the Tangale elder presented in JUNGRAITHMAYR's publication.
The craggy and hilly Muri Mountains, which are situated to the north of the Benue Lowlands, are an area with a complex pattern of settlement. This roughly 80 km long and 20 km wide mountainous area is inhabited by about 20 ethnic groups belonging to different language families. The present ethnic and linguistic situation is understood as the result of a complex series of migrations and adaptations to the natural environment. This paper will describe actual movements of settlements and consider certain conditions which may have been relevant in the decision to leave a settlement or choose a new one. The most important conditions will be the accessibility of arable land and/or pasture, accessibility of water, and conditions dependent on the historical and political context such as affording of security and possibility of defence. Therefore an interdisciplinary approach seems to be appropriate to evaluate the natural conditions for settlement and cultivation of the various places from a geographer´s point of view, to interrogate into the historical aspects and motifs of the settlement patterns and migrations with a thorough ethnological background, as well as to gain additional information from a linguistic analysis of toponymes and contact phenomena of the languages spoken in the area.
Population structure was estimated in a continuous population of a small land snail (Trochoidea geyeri). Mark-recapture experiments and randomly amplified polymorphic DNA analyses indicate that the population structure can be described by the isolation by distance model of Wright (1946). Estimates of density and dispersal suggest a neighbourhood size of 70-208 individuals on an area of 13-21 m². A principal component analysis of the randomly amplified polymorphic DNA data reveals clinal variation of genetic composition across the population, as predicted by the neighbourhood concept. An analysis of molecular variance indicates substantial genetic structuring. Comparisons of the genetic distances, expressed as euclidean distances among individuals, versus the geographic distance between sampling sites yield a highly significant positive correlation (Mantel test: r = 0.567, p<0.0001). The revealed pattern of populational subdivision on a microgeographic scale seems to be one of the principal processes generating and maintaining genetic diversity within populations of small land gastropods.
Das nachfolgende, so viel bis jezt bekannt, älteste Verzeichniss eines großen Theiles der Tafelgüter, Einkünfte und Rechte eines Erzbischofs von Mainz, und anderer auf die Erhebung und Verwaltung derselben bezüglicher Verhältnisse, war aus dem ehemaligen Kur-Mainzischen Archive, mit den die Stadt Erfurth betreffenden Akten, in das Königliche Provinzial-Archiv zu Magdeburg übergegangen. ...
In the present study the population genetic structure of the terrestrial snail Pomatias elegans was related to habitat structure on a microspatial scale. The genetic variability of 1607 individuals from 51 sampling sites in five different populations in Provence, France, was studied with an allozyme marker using population genetic methods, Mantel tests and spatial autocorrelation techniques were applied to different connectivity networks accounting for the structural features of the landscape. It is suggested that the population structure is, to a large extent, a function of the habitat quality, quantified as population density, and of the spatial arrangement of the habitat in the landscape and not of the geographical distance per se. In fragmented habitats, random genetic drift was the prevailing force for sampling sites separated by a few hundred meters.
Background: Growth rate is central to the development of cells in all organisms. However, little is known about the impact of changing growth rates. We used continuous cultures to control growth rate and studied the transcriptional program of the model eukaryote Saccharomyces cerevisiae, with generation times varying between 2 and 35 hours.
Results: A total of 5930 transcripts were identified at the different growth rates studied. Consensus clustering of these revealed that half of all yeast genes are affected by the specific growth rate, and that the changes are similar to those found when cells are exposed to different types of stress (>80% overlap). Genes with decreased transcript levels in response to faster growth are largely of unknown function (>50%) whereas genes with increased transcript levels are involved in macromolecular biosynthesis such as those that encode ribosomal proteins. This group also covers most targets of the transcriptional activator RAP1, which is also known to be involved in replication. A positive correlation between the location of replication origins and the location of growth-regulated genes suggests a role for replication in growth rate regulation.
Conclusion: Our data show that the cellular growth rate has great influence on transcriptional regulation. This, in turn, implies that one should be cautious when comparing mutants with different growth rates. Our findings also indicate that much of the regulation is coordinated via the chromosomal location of the affected genes, which may be valuable information for the control of heterologous gene expression in metabolic engineering.
The main purpose of the paper is to explain the divergent paths of development of ethno-territorial protest movements in modern democratic political systems. By focusing on the interaction between these movements and the state, the different systems of accommodation between the relevant regional and central elites will be analyzed. The study concentrates on the case studies of Québec (Canada) and Corsica (France). The paper is divided into three parts. The first part describes the traditional systems of accommodation in France and Canada. The second part is focused on the process of socio-economic modernization in the 1950s and 1960s in those countries that threatened the established patterns of elite accommodation. The third part deals with the consequences for the established patterns of elite-accommodation and new concepts of territorial management that the central states tried to establish. By looking at the different degrees of centralization and decentralization in the mentioned political systems, the question of access to the political system by new social and political actors will be discussed in detail.
Length variations of repetitive sequences in different AT-rich loop-coding regions of mitochondrial 16S rDNA in two gastropod species were discovered during intraspecific haplotype surveys. Examination of the discrete length variation of the basic repeat unit in a phylogenetic framework led to the conclusion of a microsatellite-like mutational dynamic. The observations suggest that the presence of a repetitive sequence structure alone is sufficient to trigger this dynamic.
I analysed the importance of shell size, shell shape, habitat preferences and availability, experienced climate, active dispersal and influence of Pleistocene glaciations for the range sizes of 37 Western Palaearctic Helicidae s.l. species for which a phylogeny was available. In both cross-species and phylogenetically controlled analyses, the range sizes were positively correlated to climatic tolerance, shell size, active dispersal and influence of Pleistocene glaciations. In addition, range sizes increased significantly with latitude. Multiple regression suggested that, predominantly, the influence of Pleistocene glaciations, tolerance to large annual temperature ranges and shell size influenced the distributional range sizes. Habitat preference, range and availability, active dispersal and shell shape explained no additional variance. The results suggest that the processes influencing species range size of the Helicidae s.l. are mainly related to the climatic shifts after the Pleistocene.
Alzheimer's disease-related mutations in the presenilin-1 gene (PS1) are leading to an elevated production of neurotoxic beta-amyloid 1-42 and may additionally enhance oxidative stress. Here, we provide in vivo evidence indicating that brains of transgenic mice expressing different human Alzheimer-linked PS1 mutations exhibit a reduced activity of two antioxidant enzymes. For this purpose, mice transgenic for human PS1 and for single and multiple PS1 mutations were generated. Mice with multiple PS1 mutations showed a significantly decreased activity of the antioxidant enzymes Cu/Zn superoxide dismutase and glutathione reductase already at an age of 3-4 months. As expected, this effect was less pronounced for the mice with a single PS1 mutation. By contrast, animals bearing normal human PS1 showed significantly elevated enzyme activities relative to non-transgenic littermate controls.
Background Reliable taxonomic identification at the species level is the basis for many biological disciplines. In order to distinguish species, it is necessary that taxonomic characters allow for the separation of individuals into recognisable, homogeneous groups that differ from other such groups in a consistent way. We compared here the suitability and efficacy of traditionally used shell morphology and DNA-based methods to distinguish among species of the freshwater snail genus Radix (Basommatophora, Pulmonata). Results Morphometric analysis showed that shell shape was unsuitable to define homogeneous, recognisable entities, because the variation was continuous. On the other hand, the Molecularly defined Operational Taxonomic Units (MOTU), inferred from mitochondrial COI sequence variation, proved to be congruent with biological species, inferred from geographic distribution patterns, congruence with nuclear markers and crossing experiments. Moreover, it could be shown that the phenotypically plastic shell variation is mostly determined by the environmental conditions experienced. Conclusion Contrary to DNA-taxonomy, shell morphology was not suitable for delimiting and recognising species in Radix. As the situation encountered here seems to be widespread in invertebrates, we propose DNA-taxonomy as a reliable, comparable, and objective means for species identification in biological research.
Enhanced apoptosis and elevated levels of reactive oxygen species (ROS) play a major role in aging. In addition, several neurodegenerative diseases are associated with increased oxidative stress and apoptosis in neuronal tissue. Antioxidative treatment has neuro-protective effects. The aim of the present study was to evaluate changes of susceptibility to apoptotic cell death by oxidative stress in aging and its inhibition by the antioxidant Ginkgo biloba extract EGb761. We investigated basal and ROS-induced levels of apoptotic lymphocytes derived from the spleen in young (3 months) and old (24 months) mice. ROS were induced by 2-deoxy-D-ribose (dRib) that depletes the intracellular pool of reduced glutathione. Lymphocytes from aged mice accumulate apoptotic cells to a significantly higher extent under basal conditions compared to cells from young mice. Treatment with dRib enhanced this difference, implicating a higher sensitivity to ROS in aging. Apoptosis can be reduced in vitro by treatment with EGb761. In addition, mice were treated daily with 100mg/kg EGb761 per os over a period of two weeks. ROS-induced apoptosis was significantly reduced in the EGb761 group. Interestingly, this effect seemed to be more pronounced in old mice.
Apoptosis seems to be involved in immunosenescence associated with aging. Moreover, in lymphocytes (PBL) of patients with Alzheimer's disease, an increased susceptibility to the apoptotic pathway has been described possibly due to impaired protection of oxidative stress. Accordingly, it seemed to be of particular interest to investigate the contribution of normal aging to the susceptibility from human lymphocytes to programmed cell death. We could show that PBL from elderly individuals (>60 years) accumulate apoptosing cells to a significant higher extent in spontaneous and activation-induced cell death compared to younger controls (<35 years). Treatment with the oxidative stressor 2-deoxy-D-ribose or with agonistic-CD95-antibody pronounced this effect even more implicating a higher sensitivity to reactive oxygen species and a higher functional CD95 expression, respectively. In addition, expression of the activation markers HLA-DR and CD95 was significantly increased in CD3+-cells of aged subjects, while expression of CD25 did not seem to be affected by age. Expression of Bcl-2 was increased in aging and correlated with the number of apoptotic cells.
The relevance of physiological immune aging is of great interest with respect to determining disorders with pathologic immune function in aging individuals. In recent years, the relevance of changes in peripheral lymphocytes in age-associated neurologic diseases has become more evident. Due to the lack of immunological studies, covering more than one event after mitogenic activation, we envisaged a new concept in the present study, aiming to investigate several events, starting from T cell receptor (TCR) ligation up to T cell proliferation. In addition, we addressed the question whether changes are present in the subsets (CD4, CD8) with aging. Phosphorylation of tyrosine residues declines with increasing age in CD4+ cells. Fewer levels of CD69 positive cells after 4 h mitogenic activation, altered expression of cytokines (IL2, IFN-gamma and TNF-alpha; 22 h) and lower proliferation (72 h) were determined in aging. Moreover, it could be shown that CD8+ lymphocytes react more effectively to mitogenic stimulation with reference to CD69 expression and proliferation in both age groups (<35 and >60 years old). These data indicate that T cell activation, mediated by TCR engagement, is significantly impaired in aging and both subsets are affected. However, bypassing the TCR does not fully restore T cell function, indicating that there are more mechanisms involved than impaired signal transduction through TCR only. The results will be discussed in relation to their relevance in neurodegenerative and psychiatric disorders.