scholarly journals The history of introduction of the African baobab ( Adansonia digitata , Malvaceae: Bombacoideae) in the Indian subcontinent

2015 ◽  
Vol 2 (9) ◽  
pp. 150370 ◽  
Author(s):  
Karen L. Bell ◽  
Haripriya Rangan ◽  
Christian A. Kull ◽  
Daniel J. Murphy
Keyword(s):  
West Africa ◽  
Indian Subcontinent ◽  
Central India ◽  
Adansonia Digitata ◽  
Multiple Introductions ◽  
Human Interactions ◽  
Time Period ◽  
History Of ◽  
Genetic Clusters ◽  
Southeast India

To investigate the pathways of introduction of the African baobab, Adansonia digitata , to the Indian subcontinent, we examined 10 microsatellite loci in individuals from Africa, India, the Mascarenes and Malaysia, and matched this with historical evidence of human interactions between source and destination regions. Genetic analysis showed broad congruence of African clusters with biogeographic regions except along the Zambezi (Mozambique) and Kilwa (Tanzania), where populations included a mixture of individuals assigned to at least two different clusters. Individuals from West Africa, the Mascarenes, southeast India and Malaysia shared a cluster. Baobabs from western and central India clustered separately from Africa. Genetic diversity was lower in populations from the Indian subcontinent than in African populations, but the former contained private alleles. Phylogenetic analysis showed Indian populations were closest to those from the Mombasa-Dar es Salaam coast. The genetic results provide evidence of multiple introductions of African baobabs to the Indian subcontinent over a longer time period than previously assumed. Individuals belonging to different genetic clusters in Zambezi and Kilwa may reflect the history of trafficking captives from inland areas to supply the slave trade between the fifteenth and nineteenth centuries. Baobabs in the Mascarenes, southeast India and Malaysia indicate introduction from West Africa through eighteenth and nineteenth century European colonial networks.

scholarly journals Evidence for multiple introductions of an invasive wild bee species currently under rapid range expansion in Europe

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Julia Lanner ◽  
Fabian Gstöttenmayer ◽  
Manuel Curto ◽  
Benoît Geslin ◽  
Katharina Huchler ◽  
...  
Keyword(s):  
Cluster Formation ◽  
Invasion History ◽  
European Continent ◽  
Multiple Introductions ◽  
Wild Bee ◽  
Invasion Stage ◽  
Middle Europe ◽  
History Of ◽  
Genetic Clusters ◽  
Colonization Dynamics

Abstract Background Invasive species are increasingly driving biodiversity decline, and knowledge of colonization dynamics, including both drivers and dispersal modes, are important to prevent future invasions. The bee species Megachile sculpturalis (Hymenoptera: Megachilidae), native to East-Asia, was first recognized in Southeast-France in 2008, and has since spread throughout much of Europe. The spread is very fast, and colonization may result from multiple fronts. Result To track the history of this invasion, codominant markers were genotyped using Illumina sequencing and the invasion history and degree of connectivity between populations across the European invasion axis were investigated. Distinctive genetic clusters were detected with east–west differentiations in Middle-Europe. Conclusion We hypothesize that the observed cluster formation resulted from multiple, independent introductions of the species to the European continent. This study draws a first picture of an early invasion stage of this wild bee and forms a foundation for further investigations, including studies of the species in their native Asian range and in the invaded range in North America.

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

A Very Brief History of Internet Jurisdiction

2017 ◽  
Author(s):  
Dan Jerker B. Svantesson
Keyword(s):  
Academic Community ◽  
Court Decisions ◽  
Time Period ◽  
Technological Developments ◽  
History Of

This chapter provides a brief history of Internet jurisdiction taking account of key court decisions, legislation as well as developments in the academic thinking on the topic. In doing so, it divides the history of Internet jurisdiction into four relatively distinct phases. The discussion in the chapter highlights facts such as that: (1) law has largely been reactive, responding to technological developments; (2) the level of creativity applied in the search for workable solutions was seemingly higher in the earlier stages than in more recent times; and (3) unsurprisingly, the attitudes of courts, legislators, and the academic community have varied considerably over the time period examined.

Detection of Pavement Maintenance Treatments using Deep-Learning Network

2021 ◽  
pp. 036119812110078
Author(s):  
Lu Gao ◽  
Yao Yu ◽  
Yi Hao Ren ◽  
Pan Lu
Keyword(s):  
Deep Learning ◽  
Measurement Errors ◽  
Short Term Memory ◽  
Learning Networks ◽  
Pavement Maintenance ◽  
Time Period ◽  
Learning Techniques ◽  
Maintenance And Rehabilitation ◽  
History Of ◽  
Deep Learning Network

Pavement maintenance and rehabilitation (M&R) records are important as they provide documentation that M&R treatment is being performed and completed appropriately. Moreover, the development of pavement performance models relies heavily on the quality of the condition data collected and on the M&R records. However, the history of pavement M&R activities is often missing or unavailable to highway agencies for many reasons. Without accurate M&R records, it is difficult to determine if a condition change between two consecutive inspections is the result of M&R intervention, deterioration, or measurement errors. In this paper, we employed deep-learning networks of a convolutional neural network (CNN) model, a long short-term memory (LSTM) model, and a CNN-LSTM combination model to automatically detect if an M&R treatment was applied to a pavement section during a given time period. Unlike conventional analysis methods so far followed, deep-learning techniques do not require any feature extraction. The maximum accuracy obtained for test data is 87.5% using CNN-LSTM.

The Yatela gold deposit in Mali, West Africa: The final product of a long-lived history of hydrothermal alteration and weathering

2016 ◽  
Vol 113 ◽  
pp. 73-87 ◽  
Author(s):  
Quentin Masurel ◽  
John Miller ◽  
Kim A.A. Hein ◽  
Eric Hanssen ◽  
Nicolas Thébaud ◽  
...  
Keyword(s):  
West Africa ◽  
Gold Deposit ◽  
Hydrothermal Alteration ◽  
History Of

The Royal African Company of England's West African Correspondence, 1681-1699

1993 ◽  
Vol 20 ◽  
pp. 173-184 ◽  
Author(s):  
Robin Law
Keyword(s):  
West Africa ◽  
Sierra Leone ◽  
West African ◽  
Gold Coast ◽  
Original Form ◽  
Cape Coast ◽  
General Terms ◽  
West African Coast ◽  
African Coast ◽  
History Of

This paper draws attention to an ambitious project in the publication of source material for the precolonial history of West Africa, which has recently been approved for inclusion in the Fontes Historiae Africanae series of the British Academy. In addition to self-promotion, however, I wish also to take the opportunity to air some of the problems of editorial strategy and choice which arise with regard to the editing and presentation of this material, in the hope of provoking some helpful feedback on these issues.The material to be published consists of correspondence of the Royal African Company of England relating to the West African coast in the late seventeenth century. The history of the Royal African Company (hereafter RAC) is in general terms well known, especially through the pioneering (and still not superseded) study by K.G. Davies (1957). The Company was chartered in 1672 with a legal monopoly of English trade with Africa. Its headquarters in West Africa was at Cape Coast (or, in the original form of the name, Cabo Corso) Castle on the Gold Coast, and it maintained forts or factories not only on the Gold Coast itself, but also at the Gambia, in Sierra Leone, and at Offra and Whydah on the Slave Coast. It lost its monopoly of the African trade in 1698, and thereafter went into decline, effectively ceasing to operate as a trading concern in the 1720s, although it continued to manage the English possessions on the coast of West Africa until it was replaced by a regulated company (i.e., one open to all traders), the Company of Merchants Trading to Africa, in 1750.

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