scholarly journals Did true frogs ‘dispersify’?

2017 ◽  
Vol 13 (8) ◽  
pp. 20170299 ◽  
Author(s):  
Kin Onn Chan ◽  
Rafe M. Brown
Keyword(s):  
Range Expansion ◽  
Large Scale ◽  
Late Eocene ◽  
Fundamental Interest ◽  
Biogeographic History ◽  
Ideal System ◽  
History Of ◽  
Biogeographic Regions ◽  
Geographical Expansion ◽  
The Impact

The interplay between range expansion and concomitant diversification is of fundamental interest to evolutionary biologists, particularly when linked to intercontinental dispersal and/or large scale extinctions. The evolutionary history of true frogs has been characterized by circumglobal range expansion. As a lineage that survived the Eocene–Oligocene extinction event (EOEE), the group provides an ideal system to test the prediction that range expansion triggers increased net diversification. We constructed the most densely sampled, time-calibrated phylogeny to date in order to: (i) characterize tempo and patterns of diversification; (ii) assess the impact of the EOEE; and (iii) test the hypothesis that range expansion was followed by increased net diversification. We show that late Eocene colonization of novel biogeographic regions was not affected by the EOEE and surprisingly, global expansion was not followed by increased net diversification. On the contrary, the diversification rate declined or did not shift following geographical expansion. Thus, the diversification history of true frogs contradicts the prevailing expectation that amphibian net diversification accelerated towards the present or increased following range expansion. Rather, our results demonstrate that despite their dynamic biogeographic history, true frogs diversified at a relatively constantly rate, even as they colonized the major land masses of Earth.

scholarly journals Systematic placement of an enigmatic Southeast Asian taxon Eupetes macrocerus and implications for the biogeography of a main songbird radiation, the Passerida

2007 ◽  
Vol 3 (3) ◽  
pp. 323-326 ◽  
Author(s):  
Knud A Jønsson ◽  
Jon Fjeldså ◽  
Per G.P Ericson ◽  
Martin Irestedt
Keyword(s):  
South African ◽  
Plate Tectonics ◽  
Molecular Data ◽  
Sister Taxon ◽  
Long Distance ◽  
Biogeographic History ◽  
Basal Group ◽  
History Of ◽  
Biogeographic Regions ◽  
Wallace’S Line

Biogeographic connections between Australia and other continents are still poorly understood although the plate tectonics of the Indo-Pacific region is now well described. Eupetes macrocerus is an enigmatic taxon distributed in a small area on the Malay Peninsula and on Sumatra and Borneo. It has generally been associated with Ptilorrhoa in New Guinea on the other side of Wallace's Line, but a relationship with the West African Picathartes has also been suggested. Using three nuclear markers, we demonstrate that Eupetes is the sister taxon of the South African genus Chaetops , and their sister taxon in turn being Picathartes , with a divergence in the Eocene. Thus, this clade is distributed in remote corners of Africa and Asia, which makes the biogeographic history of these birds very intriguing. The most parsimonious explanation would be that they represent a relictual basal group in the Passerida clade established after a long-distance dispersal from the Australo-Papuan region to Africa. Many earlier taxonomic arrangements may have been based on assumptions about relationships with similar-looking forms in the same, or adjacent, biogeographic regions, and revisions with molecular data may uncover such cases of neglect of ancient relictual patterns reflecting past connections between the continents.

scholarly journals The role of Central American barriers in shaping the evolutionary history of the northernmost glassfrog,Hyalinobatrachium fleischmanni(Anura: Centrolenidae)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6115 ◽  
Author(s):  
Angela M. Mendoza ◽  
Wilmar Bolívar-García ◽  
Ella Vázquez-Domínguez ◽  
Roberto Ibáñez ◽  
Gabriela Parra Olea
Keyword(s):  
Genetic Structure ◽  
Central America ◽  
Population Expansion ◽  
Central American ◽  
Fault System ◽  
Mountain Range ◽  
Amphibian Species ◽  
Biogeographic History ◽  
History Of ◽  
The Impact

The complex geological history of Central America has been useful for understanding the processes influencing the distribution and diversity of multiple groups of organisms. Anurans are an excellent choice for such studies because they typically exhibit site fidelity and reduced movement. The objective of this work was to identify the impact of recognized geographic barriers on the genetic structure, phylogeographic patterns and divergence times of a wide-ranging amphibian species,Hyalinobatrachium fleischmanni. We amplified three mitochondrial regions, two coding (COI and ND1) and one ribosomal (16S), in samples collected from the coasts of Veracruz and Guerrero in Mexico to the humid forests of Chocó in Ecuador. We examined the biogeographic history of the species through spatial clustering analyses (Geneland and sPCA), Bayesian and maximum likelihood reconstructions, and spatiotemporal diffusion analysis. Our data suggest a Central American origin ofH. fleischmanniand two posterior independent dispersals towards North and South American regions. The first clade comprises individuals from Colombia, Ecuador, Panama and the sister speciesHyalinobatrachium tatayoi; this clade shows little structure, despite the presence of the Andes mountain range and the long distances between sampling sites. The second clade consists of individuals from Costa Rica, Nicaragua, and eastern Honduras with no apparent structure. The third clade includes individuals from western Honduras, Guatemala, and Mexico and displays deep population structure. Herein, we synthesize the impact of known geographic areas that act as barriers to glassfrog dispersal and demonstrated their effect of differentiatingH. fleischmanniinto three markedly isolated clades. The observed genetic structure is associated with an initial dispersal event from Central America followed by vicariance that likely occurred during the Pliocene. The southern samples are characterized by a very recent population expansion, likely related to sea-level and climatic oscillations during the Pleistocene, whereas the structure of the northern clade has probably been driven by dispersal through the Isthmus of Tehuantepec and isolation by the Motagua–Polochic–Jocotán fault system and the Mexican highlands.

The Concept of Explanatory Adequacy

2016 ◽  
pp. 96-113 ◽  
Author(s):  
Luigi Rizzi
Keyword(s):  
Large Scale ◽  
Generative Grammar ◽  
Language Learner ◽  
Minimalist Program ◽  
Parametric Models ◽  
The Other ◽  
History Of ◽  
Explanatory Adequacy ◽  
The Impact ◽  
Linguistic Phenomenon

This chapter illustrates the technical notion of ‘explanatory adequacy’ in the context of the other forms of empirical adequacy envisaged in the history of generative grammar: an analysis of a linguistic phenomenon is said to meet ‘explanatory adequacy’ when it comes with a reasonable account of how the phenomenon is acquired by the language learner. It discusses the relevance of arguments from the poverty of the stimulus, which bear on the complexity of the task that every language learner successfully accomplishes, and therefore define critical cases for evaluating the explanatory adequacy of a linguistic analysis. After illustrating the impact that parametric models had on the possibility of achieving explanatory adequacy on a large scale, the chapter addresses the role that explanatory adequacy plays in the context of the Minimalist Program, and the interplay that the concept has with the further explanation ‘beyond explanatory adequacy’ that minimalist analysis seeks.

Ivan Kavaleridze`s dramaturgy on the Sumy stage

2021 ◽  
Author(s):  
D.V. Budianskyi
Keyword(s):  
Large Scale ◽  
Musical Comedy ◽  
Historical Figures ◽  
Wide Range ◽  
Socialist Realist ◽  
History Of ◽  
Characteristic Features ◽  
Old Men ◽  
The Impact ◽  
First Time

The characteristic features of I. Kavaleridze’s drama is considered in the article. It is noted that there are signs of the artist’s individuality, attraction to expressionist forms, artistic techniques characteristic for the art of sculpture: symbolism, monumentality, hyperbole. I. Kavaleridze was well versed in the drama laws, understood the specifics of the stage events construction, had a large arsenal of literary means, thanks to which the characters’ monologues and dialogues were extremely expressive and colorful. In his work, he implemented original solutions that were ahead of time. Therefore, many of the artist’s ideas and achievements received due recognition only after his death. I. Kavaleridze’s creative heritage covers a wide range of both purely artistic and general philosophical problems. Among them the formation of the era of modernism and its features in the Ukrainian art of the early XX century, the impact of revolutionary ideas on the work of the 1920s, the role of spiritual leaders of the Ukrainian people T. Shevchenko and G. Skovoroda in the formation of national consciousness, political and ideological pressure on figurative art language and the formation of a socialist-realist canon, etc. The analysis of the productions of I. Kavalerizde’s plays “The First Furrow” and “Gregory and Paraskeva” on the stage of the Mykhailo Shchepkin Sumy Theater of Drama and Musical Comedy in 1970-1972. The article notes that these plays were staged in Sumy for the first time in the history of Ukrainian theater. The premiere of “The First Furrow” (the play was called “Old Men”) took place on March 19, 1970. The figure of the national genius Hryhoriy Skov oroda was als o embodied for the first time on t he stage in Sumy in th e play “Hryhoriy and Paraskeva”. It premiered on October 21, 1972. I. Rybchynsky, Honored Artist of the USSR, performed the production. Creating generalized historical outlines of people’s life, features of life at that time, depicting psychological portraits of people in various, sometimes-dramatic collisions, in the productions of I. Kavaleridze’s plays on the Sumy stage the emphasis was on universal values such as virtue, love. The main character was the Ukrainian people, who nurtured such large-scale historical figures, gave them strength and wisdom for great achievements. Based on publications in periodicals of that time, memoirs of Ukrainian directors, the peculiarities of the director’s interpretation, stenographic and musical design of these plays on the Sumy stage are considered. Considerable attention is paid to the analysis of acting works in I. Kavaleridze’s plays. In particular, the peculiarities of the actor’s embodiment of the image of the national genius Hryhoriy Skovoroda on the stage are presented. It is noted that I. Kavaleridze’s plays, created in a difficult political, social and ideological context, are rightly considered to be highly artistic works of Ukrainian drama. Their staging was carried out on various theatrical stages, including Mykhailo Shchepkin Sumy Theater of Drama and Musical Comedy is an important page of national theatrical art.

scholarly journals The Efficacy of Ethnic Stacking: Military Defection during Uprisings in Africa

2019 ◽  
Vol 5 (4) ◽  
pp. 695-702 ◽  
Author(s):  
Julien Morency-Laflamme ◽  
Theodore McLauchlin
Keyword(s):  
Large Scale ◽  
Armed Forces ◽  
Future Research ◽  
Group Loyalty ◽  
Limited Support ◽  
History Of ◽  
Group Members ◽  
Using Data ◽  
The Cost ◽  
The Impact

Abstract Does ethnic stacking in the armed forces help prevent military defection? Recent research, particularly in Africa and the Middle East, suggests so; by favoring in-groups, regimes can keep in-group soldiers loyal. In-group loyalty comes at the cost of antagonizing members of out-groups, but many regimes gladly run that risk. In this research note, we provide the first large-scale evidence on the impact of ethnic stacking on the incidence of military defection during uprisings from below, using data on fifty-seven popular uprisings in Africa since formal independence. We find clear evidence for the downside: ethnic stacking is associated with more frequent defection if out-group members are still dominant in the armed forces. We find more limited support for the hypothesized payoff. Ethnic stacking may reduce the risk of defection, but only in regimes without a recent history of coup attempts. Future research should therefore trace the solidification of ethnic stacking over time.

Weathering the Soviet Countryside: The Impact of Climate and Agricultural Policies on Russian Grain Yields, 1958–2010

2013 ◽  
Vol 40 (1) ◽  
pp. 115-143 ◽  
Author(s):  
Nikolai M. Dronin ◽  
Andrei P. Kirilenko
Keyword(s):  
Large Scale ◽  
State Level ◽  
Relative Role ◽  
Agricultural Policies ◽  
Production Potential ◽  
Russian Agriculture ◽  
Land Privatization ◽  
History Of ◽  
The Impact

Agriculture in Russia has always had to contend with unfavorable climate. At the same time, large-scale socio-economic experiments have also strained the country’s food production potential throughout the 20th century. The relative role of climate and state agricultural policies in affecting production of cereals was studied for the period of 1958–2010. The study used statistical yield modeling to explain the variations in observed yields with slowly changing progress in technology and management and weather variability. The correlation between the actual and weather-explained yields is moderate to high: measured at the level of the entire country, Pearson’s r is 0.74 and Spearman’s rho is 0.68. Further, we suggest that the residual yield variability can be explained partially with the influence of large-scale changes in agricultural policies at the state level. Between these policies, we consider the following key periods in the history of Russian agriculture: “Virgin Lands” campaign (end of 1950s), Kosygin-Liberman initiatives (late 1960s), Brezhnev’s investment programmes in response of stagnation of agriculture (late 1970s – early 1980s), Gorbachev’s “Perestrojka” (1985–1991), and land privatization and price liberalization (1990s).

scholarly journals RAPID DATA COLLECTION FOR THE AUDIT OF MONUMENTS & MEMORIALS IN SOUTH AFRICA

2021 ◽  
Vol XLVI-M-1-2021 ◽  
pp. 313-320
Author(s):  
C. Jackson ◽  
M. Nkhasi-Lesaoana ◽  
L. Mofutsanyana
Keyword(s):  
South Africa ◽  
Public Space ◽  
Large Scale ◽  
National Audit ◽  
The Public ◽  
Funding Mechanism ◽  
History Of ◽  
Monuments And Memorials ◽  
The Impact ◽  
Roll Out

Abstract. The tradition of memorialising people and events through physical constructions such as statues and monuments like in many countries, has shaped the public space of a modern South Africa. Considering the colonial and apartheid history of South Africa, these physical markers, often uncontextualized, continue to maintain positions of prominence within the modern streetscape.Since the turn of the democratic era in South Africa, a pressing need has existed to assess the impact of the markers on the heritage landscape of the country. An endeavour made more difficult by a lack of a comprehensive inventory of these resources across the country.The National Audit of Monuments and Memorials (NAMM) was designed to address this gap through a full national survey of monuments and memorials, conducted under the auspices of a job creation stimulus package designed to create short term employment in the wake of the economic fallout from the Covid-19 pandemic. Undertaking this project under this funding mechanism required that all phases of the project be undertaken within a six-month period.The compressed timeframes associated with this project required an approach that could support a level of fluidity to address the challenges of undertaking a project of this nature, whilst ensuring that the data collected by field surveyors can be monitored and included in the inventory of the national estate in an effective manner.The aim of this paper is to discuss and showcase the tools and workflows used to roll out and manage the large-scale national audit of monuments and memorials across South Africa.

scholarly journals Reconstructing Squamate Biogeography in Afro-Arabia Reveals the Influence of a Complex and Dynamic Geologic Past

2020 ◽  
Author(s):  
Héctor Tejero-Cicuéndez ◽  
Austin H. Patton ◽  
Daniel S. Caetano ◽  
Jiří Šmíd ◽  
Luke J. Harmon ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Arabian Plate ◽  
Range Contraction ◽  
Biogeographic Patterns ◽  
Biogeographic History ◽  
Novel Approach ◽  
Ideal System ◽  
History Of ◽  
Dispersal Corridor ◽  
External Forces

ABSTRACTThe geographic distribution of biodiversity is central to understanding evolutionary biology. Paleogeographic and paleoclimatic histories often help to explain how biogeographic patterns unfold through time. However, such patterns are also influenced by a variety of other factors, such as lineage diversification, that may affect the probability of certain types of biogeographic events. The complex and well-known geologic and climatic history of Afro-Arabia, together with the extensive research on reptile systematics in the region, makes Afro-Arabian squamate communities an ideal system to investigate biogeographic patterns and their drivers. Here we reconstruct the phylogenetic relationships and the ancestral geographic distributions of several Afro-Arabian reptile clades (totaling 430 species) to estimate the number of dispersal, vicariance and range contraction events. We then compare the observed biogeographic history to a distribution of simulated biogeographic events based on the empirical phylogeny and the best-fit model. This allows us to identify periods in the past where the observed biogeographic history was likely shaped by forces beyond the ones included in the model. We find an increase in vicariance following the Oligocene, most likely caused by the fragmentation of the Afro-Arabian plate. In contrast, we did not find differences between observed and expected dispersal and range contraction levels. This is consistent with diversification enhanced by environmental processes and with the establishment of a dispersal corridor connecting Africa, Arabia and Eurasia since the middle Miocene. Finally, here we show that our novel approach is useful to pinpoint events in the evolutionary history of lineages that might reflect external forces not predicted by the underlying biogeographic model.

scholarly journals Hyainailourine and teratodontine cranial material from the late Eocene of Egypt and the application of parsimony and Bayesian methods to the phylogeny and biogeography of Hyaenodonta (Placentalia, Mammalia)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2639 ◽  
Author(s):  
Matthew R. Borths ◽  
Patricia A. Holroyd ◽  
Erik R. Seiffert
Keyword(s):  
North America ◽  
Bayesian Methods ◽  
Middle Eocene ◽  
Phylogenetic Analyses ◽  
Late Eocene ◽  
Biogeographic History ◽  
Close Relationship ◽  
History Of ◽  
New Material ◽  
Latest Eocene

Hyaenodonta is a diverse, extinct group of carnivorous mammals that included weasel- to rhinoceros-sized species. The oldest-known hyaenodont fossils are from the middle Paleocene of North Africa and the antiquity of the group in Afro-Arabia led to the hypothesis that it originated there and dispersed to Asia, Europe, and North America. Here we describe two new hyaenodont species based on the oldest hyaenodont cranial specimens known from Afro-Arabia. The material was collected from the latest Eocene Locality 41 (L-41, ∼34 Ma) in the Fayum Depression, Egypt.Akhnatenavus nefertiticyonsp. nov. has specialized, hypercarnivorous molars and an elongate cranial vault. InA. nefertiticyonthe tallest, piercing cusp on M1–M2is the paracone.Brychotherium ephalmosgen. et sp. nov. has more generalized molars that retain the metacone and complex talonids. InB. ephalmosthe tallest, piercing cusp on M1–M2is the metacone. We incorporate this new material into a series of phylogenetic analyses using a character-taxon matrix that includes novel dental, cranial, and postcranial characters, and samples extensively from the global record of the group. The phylogenetic analysis includes the first application of Bayesian methods to hyaenodont relationships.B. ephalmosis consistently placed within Teratodontinae, an Afro-Arabian clade with several generalist and hypercarnivorous forms, andAkhnatenavusis consistently recovered in Hyainailourinae as part of an Afro-Arabian radiation. The phylogenetic results suggest that hypercarnivory evolved independently three times within Hyaenodonta: in Teratodontinae, in Hyainailourinae, and in Hyaenodontinae. Teratodontines are consistently placed in a close relationship with Hyainailouridae (Hyainailourinae + Apterodontinae) to the exclusion of “proviverrines,” hyaenodontines, and several North American clades, and we propose that the superfamily Hyainailouroidea be used to describe this relationship. Using the topologies recovered from each phylogenetic method, we reconstructed the biogeographic history of Hyaenodonta using parsimony optimization (PO), likelihood optimization (LO), and Bayesian Binary Markov chain Monte Carlo (MCMC) to examine support for the Afro-Arabian origin of Hyaenodonta. Across all analyses, we found that Hyaenodonta most likely originated in Europe, rather than Afro-Arabia. The clade is estimated by tip-dating analysis to have undergone a rapid radiation in the Late Cretaceous and Paleocene; a radiation currently not documented by fossil evidence. During the Paleocene, lineages are reconstructed as dispersing to Asia, Afro-Arabia, and North America. The place of origin of Hyainailouroidea is likely Afro-Arabia according to the Bayesian topologies but it is ambiguous using parsimony. All topologies support the constituent clades–Hyainailourinae, Apterodontinae, and Teratodontinae–as Afro-Arabian and tip-dating estimates that each clade is established in Afro-Arabia by the middle Eocene.

Evaluating Usability to Improve Efficiency in E-Learning Programs

2009 ◽  
pp. 315-320
Author(s):  
Emilio Lastrucci ◽  
Debora Infante ◽  
Angela Pascale
Keyword(s):  
Large Scale ◽  
Human Factor ◽  
Graphic Interface ◽  
Training Costs ◽  
Usability Problems ◽  
Learning Programs ◽  
Gradual Introduction ◽  
History Of ◽  
E Learning ◽  
The Impact

The history of usability began almost 20 years ago when computers were about to be used outside the designer and programmer environment. Until the 1980s software was mostly produced and used by designers so usability was taken for granted. In 1983, the first computers providing a graphic interface and a mouse were produced by Apple for distribution on a large scale. The gradual introduction of computers to offices and houses began creating usability problems. The development of computers was guided mainly by the technology available at that time. Gradually, the impact of training costs, errors in the interaction between user and computer, and the evolution of studies regarding the “human factor”, carried out by psychologists and ergonomics experts, led to a reflection on the importance of the target users.

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