1,721,956 research outputs found
An East African record of vegetation and climate as interpreted from the palynology of the terrestrial Late Neogene and Quaternary sediments of the southern part of Lake Albert, Uganda
No full textThe Neogene of East Africa was a time and place of critical importance in hominid evolution, and yet our current understanding of its climatic history is a composite record based on different proxies from a series of stratigraphically (temporally) restricted outcrop sections. Whilst these studies provide an overall picture of progressively increasing aridity with a long-term trend toward more open savannah vegetation, there is as yet no single complete Neogene climatic record from a location in East Africa which epitomises this scenario. This study therefore aims to produce the first long-term vegetation and climatic records for the East African Neogene by undertaking a systematic palynological analysis of the plant communities recorded in two continuous Late Neogene lacustrine borehole sequences from Lake Albert, in the Western Riftof the East African Rift Valley, Uganda. Detailed systematic analysis of borehole cuttings samples has allowed the first comprehensive determination of the botanical affinities of the abundant and well-preserved palynomorphs recovered, permitting the identification of ecologically, climatically and stratigraphically significant taxa. The latter have been used to establish an age framework, which in turn have permitted accurate comparison with outcrops dated by macrofossils and tephrostratigraphy. A Nearest Living Relatives (NLRs) statistical analysis of the climatic “profiles” of the pollen and spores has produced a climatic profile which reveals a fluctuating, but overall gradual trend of decreasing rainfall and temperature through the Neogene. In addition, Principal Components Analysis (PCA), Discriminant Analysis (LDA) and Cluster Analysis reveals a central rift plant community which steadily increased in biodiversity through the Neogene, whereas the rift margin vegetation was less stable, taking considerable time to recover from the sporadic, tectonically controlled development of alluvial fans, which were characterised by much lower diversity plant communities. This palynological analysis of the lacustrine sediments from the Albert Rift has for the first time shown that palynomorphs can provide a long-term and continuous record of vegetation and climatic change in East Africa, providing pollen profiles which illustrate the increased development of savannah, and shifts in the profile which can be related to continent-wide climatic events of intra-Late Pliocene, Early Pleistocene and Mid Pleistocene age
Alien Registration- Shaw, David W. (Portland, Cumberland County)
Full text linkhttps://digitalmaine.com/alien_docs/21968/thumbnail.jp
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
- …
